US2346437A - Moisture control system - Google Patents

Description

April 11, 1944; R 2,346,437 v MOISTURE CONTROL SYSTEM Filed Aug. 10, 1939 5 Sheets-Sheet 1 FIG. I.

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\NVENTOR ANKER E. KROGH ATTORN EY April 11, 1944. E, KROGH 2,346,437

' MOISTURE CONTROL SYSTEM Filed Aug. 10, 1939 5 Sheets-Sheet 2 93 INVENTOR ANKER E. KROGH ATTORNEY April 11, 1944.

A. E. KROGH MOISTURE CONTROL SYSTEM Filed Aug. 10, 1939 5 Sheets-Sheet 3 INVENTOR ANKER E. KROGH ATTORNEY April 11, 1944. E KR GH 2,346,437

MOISTURE CONTROL SYSTEM Filed Aug. 10, 1939 5 Sheets-Sheet 4 FIG. 7.

INVENTOR ANKER E. KROGH BYM ATTO R N EY April 11, 1944. E KROGH 2,346,437

MOI STURE CONTROL SYSTEM Filed Aug. 10. 1939 5 Sheets-Sheet 5 INVENTOR ANKER E.KROGH WW ATTORNEY Patented Apr. 11, 1944 MOISTURE CONTROL SYSTEM Anker E. Krogh, Mount Airy, Pa., assignor to The Brown Instrument Company, Philadelphia, Pa., a corporation of Pennsylvania Application August 10, 1939, Serial No. 289,404

43 Claims.

The present invention relates to apparatus for controlling the moisture content of various materials, and more particularly to the preparation of'yarn in a slasher as it is wound on a loom beam preparatory to the insertion of the latter into a loom in which the yarn is incorporated into a woven fabric.

The so-called slashing machines used for sizing and drying the yarn as it is wound on a loom beam consist, in general, of supports for the warp and loom beams, a pan or trough for containing the sizing material and squeezing rolls between which the yarn passes afte it has been size'd, steam heated drying rolls or drums over which the yarn passes after being sized and before it is wound on'the loom roll, and some means to drive the drums. Quite often a slasher is also supplied with a so-called spider fan which forces air past the dried yarn and a hood over the drying drums through which the moisture driven irom the yarn is exhausted. Each of these component parts of a slasher has its own effect on the moisture content of the yarn as it is wound on the loom beam.

For the attainment of the best results in the weaving process it is essential that the yarn have the proper moisture content. This content is expressed in percentage and may vary over a narrow range, the range changing with the type of yarn. It is a general object of the present invention to control the operation of the various component parts of a slasher so that the optimum value oi moisture content oi the yarn may be obtained.

It has been the custom to control the pressure or temperature of the steam in the drying drums in an attempt'to control the moisture content 01' the yam' on a slasher. This has not, however, been satisfactory since the steam pressure along with other variables such as size box level and temperature, atmospheric temperature, fan speed and yarn tension are at best mere stabilizing conditions. In order to deliver yarn at uniform moisture, an ideal control system must compensate for all variables, some of which cannot be stabi- H2611. The control of my system compensates for all of the variables by measuring the actual moisture content of the yarn and varying the speed or the slasher to keep it at a maximum safe operating value at all times.

In the operation of the system a very small current flows through the yarn and is detected by a modified bridge circuit, which is continually kept n balance by a motor driven slide-wire withinthe instrument. In the instrument are also a pair of motor driven contacts which in turn control the speed of the slasher.

At all times there is considerable yarn on the slasher drying drums which will not feel the full effect of a speed change. Only that yarn which enters the size box after the speed change has been made will feel the complete effect of it, hence, it is important following, a speed change that no further changes he made during the time the moisture measuring instrument is actually measuring the yarn that has ielt the full effect. For this purpose an electrical interrupter is at-- tached to the slasher and is so constructed that the circuit to the transmission control motor is completed at intervals sumcient to permit the slasher to be completely stripped of yarn before another change is made. If the moisture measuring instrument shows that the change was insuficlent an additional speed change is produced. By driving the interrupter from the measuring roller on the slasher, this system adapts itself to various yarns regardless of the required speed.

Since it is not desirable to change the normal slasher speed due to stopping or slow motion of the drums a switch is operated by the slasher shifter handle which operates to disconnect the control system. When the slasher switch is returned to its running position the control again starts to function but in order to permit the baked yarn on the slasher to he removed before speed changes are instituted a time interval elapses bei'ore a timing unit operated by the switch, closes its contacts and full control is re sumed.

It is an object of this invention to provide a highly accurate means to control the speed of the drying drums of a slasher in response to the moisture content of the yarn being wound on a loom beam so that the yarn may remain for a longer or shorter time in contact with the drums. A measurement of the yarn's moisture content is made and the speed oi the drums controlled intermittently in response to this measurement.

It is a further object of my invention to reduce the pressure of the steam supplied to the drums when the slasher is stopped to prevent overdrying of the yarn that is at that time in engagement with the drums. It is a further object of my invent on to control other variables in the slashing process such as the speed of the spider fan, the spee i of the exhaust fan in the hood, and the tem perature of the size in combination with the speed control of the drying drums.

The various features of novelty which eharac terlze my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects obtained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:

Fig. 1 is a diagrammatic side view, partly in section, of the control system of my invention;

Fig. 2 is a top view, partly in section, of Fig. 1, with certain of the parts omitted:

Fig. 3 is a wiring diagram of my control system;

Fig. 4 is a wiring diagram of a less elaborate y Fig. 5 is a view of the slasher driven interrupter;

Fig. 6 is a diagrammatic view or the system as used when more than one slasher unit is driven from the same power supply;

Fig. 'I is a view of my control system combining speed and exhaust fan control; 7

Fig. 8 shows another type of exhaust control;

Fig. 9 is a view of my invention combining speed and steam pressure control;

Fig. 10 is a view of my invention combining speed and a difierent type of steam pressure control;

Fig. 11 is a view of my invention combining speed and spider fan control; and

Fig. 12 is a view of my invention combining speed and size temperature control.

Referring to Fig. 1 yarn is led from the right from a warp beam (not shown) around the rollers 2 in a size tank 3, over drying drum d and 5, guide rollers B and l and past a guide roller 8 to be wound on a loom beam (not shown). 00- operating with the guide roller 6 is a measuring roller 9 which is electrically connected to 9. moisture measining instrument M; the details of which will be described below.

Size is admitted to the tank- 8 through a line it) that has a valve in it which may be operated automatically, if desired, by any suitable means to maintain the size level constant. The temperature of the size is kept constant at some predetermined value by means of a temperature controller i i in order that the viscosity and penetratin power of the size may remain the same. The instrument ii, shown as a Brown air-operated controller, is responsive to size temperature by means of a temperature responsive bulb 12 in the tank 3 and a connecting capillary i3. Air under a suitably constant pressure is supplied through a pipe 84 and is .varied by the instrument ii to apply difierent pressures on the diaphragm of an air operated valve 95 to thereby vary the opening of that valve and accordingly change the admission rate of heating steam to the size tank.

Steam is supplied to the valve iii and tank 3 through a line is which also supplies the heating steam to the drying drums and b. In order to maintain the pressure of the steam in the drying drums constant an air operated valve ll of the spring closed type is used. The air pressure supplied to the diaphragm of this valve is regulated by an air control pressure controller iii that is normally supplied with air through a line 99 having a pressure regulator is in it. As the galue of the pressure in the drying drums changes the pressure applied to the diaphragm of valve ll through line at is altered by the controller is to vary the opening of valve ill. A second air line asaaesv 22 supplying air to controller iii is in parallel with the line it and is provided with a pressure regulator 23 that is set at a much. lower value than the regulator 2@. At times during the operation of the system a solenoid valve 26 in the line It is closed, thus supplying air to controller is through line 22 at a lower pressure. The result of this is that the spring of valve ll will tend to close that valve and reduce the steam pressure in drums 4i and 5. The manner in which the valve 26 is operated'will be described below in the operation of the system.

During the slashing process the efilciency of the slasher is increased appreciably if the moisture driven from the yarn is removed. In order to accomplish this a hood 25 is located over the drying drums and the size box and is provided with an exhaust duct 2t having an exhaust fan 27 located in the duct, driven by a motor 28.

A spider fan 29 driven at a suitably constant, but variable, speed by the motor its is located so that its blast passes over the yarn after it has left the drying drums and before the yarn is engaged by measuring roller 9. This fan 29 may have some small drying function, but its value lies chiefly in removing loose particles of size and lint from the yarn before it is wound upon the loom beam.

The drying drums 4i and 5 are driven at various speeds depending upon the moisture content oi the yarn passing under roller 9 by means of a motor Eli and a variable speed transmission 3d of the Reeves type. Fast and loose pulleys 35 on the shaft of the motor 38 transmit its power through a belt 32 to the pulley 33 of the driving shaft 35 of the transmission. A variable speed transmission of this type consists of driving and driven shafts fill and Bil, respectively, each having an expansible conical pulley and 38 upon it. These pulleys are connected by a belt 3Q so that shaft 36 is driven by shaft ill at a speed dependent upon the relative sizes or pulleys ill and 88. The sizes oi the pulleys, and thereby the speed of shaft 36 may be changed by pivoting rods to, which are connected to the pulleys, around their center points. This is accomplished by having the outer ends of the rod it in threaded engagement with right and aft hand threads of a screw shaft 4H that is rotated by reversible motor 63. The motor as is controlled from instrument M. The transmission drives the drying drums d and 5 from the shat 36 by means of gears 42 connecting that shaft and the shafts of the drums.

The belt 32 may be shifted from the fast to the loose pulley ill by means of a manually operated shipper rod it which is provided with a projection 65 that'is adapted to adjust the position of a switch as during its movement.

0n the shaft :3 of the drum 3 there is another pulley 67 which, through a belt 38 drives a shaft 69 of an interrupter so to periodically open and close the circuit from the measuring instrimient to the motor 68 in a manner to be described in detail below. The interrupter serves the function of and may be called a speed responsive element since the closing or the switch thereof is in response to the speed of the slasher by which it is driven.

The slasher driven interrupter E563 is illustrated more in detail in Fig. 5. The shaft 69, through suitable gearing 5i, drives shafts E52 and E33, at rates depending upon the slasher speed. Mounted on shaft 52 are two cams sea and ME which when taken together, form a single cam 6d whose low portion may be varied in extent by placing a pin 55 in an opening in cam 54B and one of a series of openings in the cam 54A. On shaft 53 is a cam 55 that, because of the gearing BI, i rotated at a much slower speed than is the cam 55. Below and between the cams is a shaft 51 upon which is mounted a bell-crank 58 that is normally biased in a clockwise direction by spring 59. The lever 58 is provided on each of its arms with a cam following roller, one. for each of the cams 54 and 56, and is provideo below its pivot with a bracket 50 adjustably i'astened thereto and supporting a mercury switch 6|. The arrangement i such that as the cams rotate their respective low portions will periodically come under the cam following rollers to Permit lever 58 to move clockwise and close switch The cam 55 is driven by the gearing from the slasher at such a speed that its low portion comes under its roller once for approximately every twenty yards of yarn that move over the drying drums. The cam 54 is so adjusted that the switch BI is permitted to stay closed for some predetermined length of time. The switch BI controls the time of operation of the speed adjusting motor 43 in a manner.

presently to be described. a

The particular type of moisture measuring instrument disclosed herein forms no part of my invention except in combination with the rest of the measuring and controlling system. Referring now to Fig. 3 there is shown a wiring diagram in connection with which will be explained the operation of the system.

An electric measuring and amplifying circuit by which the moisture content of the yarn I may be measured in order to control the energization of motor 43 and the speed of the slasher comprises a first balanced Wheatstone bridge arrangement, two adjacent arms of which include similar electronic valves 62 and 53, respectively, which may be heater type triodes whose heating elements 62a and 83a may be energized from any suitable source. The other two bridge arms include resistances 64 and 85. The opposed normally equal terminals 66 and 81 of the bridge are connected by conductors to the terminals of a center-zero galvanometer B8. The other two opposed junctions 69 and 10 of the bridge circuit are connected to a suitable source of direct current which is diagrammatically shown by the plus and minus marks.

A second Wheatstone bridge electrically connected to the first includes the web moisture measuring connections which comprise the roller 9 that is spring-biased into engagement with the yarn I by a spring II. The resistance of the yarn I between the roller 9 and the roller 8, which is shown as being connected to the bridge, is variable and responsive to the moisture content of the web I. The normally equipotential junctions I2 and I3 of the second bridge are connected to the grids 62b and 63b of the triode elements 52 and 53, respectively. The othe two junctions 14 and of the second bridge are connected to the junctions 69 and III, respectively, of the first bridge, the junction 15 being connected directly and the junction 14 being connected through a biasing resistance I5. The points 13 and 14 and 13 and 15 are connected. respectively, by fixed resistors 11 and I8, while the points I2 and 14 are connected by a variable resistance I! which is adjusted to rebalance the bridge when it is unbalanced by a change in the resistance 01' yarn I. Both of the bridges 'line, the resistance iii beii have a ground connection on the positive side at 80.

The bridge junction 69 is connected through the resistance 716 to the net tive side of the of such value that each or the grids 62b 6% has notch-= tial which is negative with respect to the potential of the corresponding cathodes 62c and 880, respectively.

In operation with the normal balanced condition of the bridges, the grids and 585 are similarly negative relative to respective cathodes 62c and @530, the similar triodes (3E and 63 are equally conductive, current flows through the bridge arm and are equal and the bridge junction points 38 and iii! are therefore at the same potential, and pointer 68a of the galvanometer will be in its neutral position. On a decrease in the moisture content of the yarn i in; contact with roller 9, the crease in the value of the resi 'ance between rollers 8 and 9 results in an incr potential drop in that leg of the bridge, and time ncreases the extent to which the grid 62b is negative rein tive to cathode 620. This diminishes the conductivity of the triocle (B2 and makes the potential of the bridge junction 536 higher than the potential of junction 6?. Furtherr ore, the po tential difference between the b e junctions B5 and 51, due to the increa oi otial drop between junctions l2 and b amplified since the decrease in the current v through the triode 62 decreases the current now through the resistance l6, and increases the potential of the grid 6% in a no this direction relative to the potential of the corrod to make the triode 83 more conductive. The re sultant increase through the resistance lowers the potential of junction 6?. @onversely, an increase in the moisture content of the I and the resultant reduction resistance increases the potential of the junction point and decreases the potential of ions point The pointer 68a of the galvano er will deflect In one direction or the titer from its neutral position as the potential. of bridge junction 86 rises above or falls below the potential of junction 51, and the deflect? to position of this pointer is relied upon to mechanism which will indicate and record the of the moisture content of the yarn i. For this purpose, the end of pointer 38a is provided with a contact that, upon deflection of the salve-nometer. will engage one of contacts Gin or 8th to energize one field or the other of a reversible motor 8| that is used to rebelance the bridge and move a pen and indicator.

A contact 719a has attached to for movement with it a combined pen and indicating element 19b that is moved, respectively, along the resistance 79, the chart 82 and scale 83 the motor BI in response to unbalance of the bridge circuits as a result of a change in the moisture content of the yarn l. The rotor till is energized by a deflection or" the galvanometer pointer 68a in a direction to move the contact lilo to rebalance the bridges. Attached for movement with, but insulated from, the is a cow tact 84 which is adapted to brought into engagement with one of a pair of contacts 85a or 8517 mounted on a block The reversible motor 43 that is used to adjust the transmission 3d is energized for rotation in one direction or the other as the contact O l is mov d in ment with one of the contacts 'r i this manner, as the bridge circuits are unbalanced as a result of a change in moisture content of the web t, the motor M will be energized to rebalance the bridge and move a pen and indicator across a chart and scale, respectively to record and indicate the value thereof. This movement is also used to adjust the transmission 34 by means of motor $3 in an amount and direction to change the speed of the drums d and 5 so that they will return the web to its normal moisture content.

The block 85 to which contacts 850. and 85b are attached is mounted on a screw threaded mem ber 85 so that these contacts can be shifted with respect to contact M in order to change the control point of the instrument, or to change the moisture content which the instrument will tend to keep in the web.

In order that the speed of the slasher is intermittently adjusted in accordance with the length of yarn that passes the drying drums suitable interrupters are provided in the circuit from the contact as and contacts the and 85b and the motor 63. This is done so that the eiiect of each speed change may be measured by the instrument M before'succeeding speed changes are made.

Ihe motor 63 is supplied with current from a suitable A. C. line through a transformer 81. One side of the transformer 87 is connected directly to the motor 43 by line 88 and the other side is connected through line 89, slow push button 90, fast push button 9i, interrupter switch 6!, stop switch illl and line 92 to contact ed. The contact 85b is connected directly to the field dab of motor 43, which field is used to slow down the slasher speed, by line 93. Contact 85a is connected by line 9 3, normally closed switch 95 and line as to field lieu; of motor 33, which field is used to rotate the motor in a direction to speed up the slasher.

In the normal operation of the instrument the moisture content of the yarn is continually measured and recorded. As the moisture varies the contact 86 will engage either contact 85a or 852) to cause rotation of the motor 423 in the proper direction to adjust the variable speed transmission in order to change the speed of the slasher to compensate for these variations. The interrupter switch Bl, operated by the slasher, is periodically opened so that after each speed change the yarn then on the drying drums will have been removed so that the full efiect of the speed change may be known before another change is made. Since switch 6i is driven from the slasher roll it will always be operated in synchronism therewith to insure that the proper amount of yarn has passed.

When, in order to stop or slow down the slasher for any reason, the shipper rod id is moved to shift belt 32 to the loose pulley, its projection 35 will operate switch iii? to move it from the position shown in Fig. 3 into engagement with the lines 91!. This movement performs two operations. First, the bridging of lines 9? shunts out part of resistance it in the bridge circuit so that the bridge will become unbalanced and motor 8i will move the pen down scale. As the pen moves down scale a projection 98 on the pen carriage engages switch support 99 to tilt it against the bias of its spring to open switch ltd and deenergize the solenoid valve 2d thus closing on air line it to the pressure controller is. Low pressure air through line 22 is then supplied to the controller and valve ii to permit that valve asi es? to close under its spring pressure and reduce the steam to the drying drums. In this manner the temperature of the rolls is reduced to prevent undue baking of the yarn while the slasher is at rest or running slowly.

Secondly, the moving of switch 38 to its upper position of Fig. 3 deenergizes relay HM so that its switch member lilla may drop to its low position. This first opens line M2 to deenergize relay W3 so that switch $35 may open and disconnect the fast neld 43a oi motor 53 from the instrument. This is necessary because when the drum temperatures are reduced and the slasher is stopped the yarn will be wet. Therefore it is necessary that the setting of the igansmission is not altered in a direction to speed up the slasher as yam will not be dry enough before the slasher speed can be reduced as the slasher is started.

In order to further insure that the transmission setting will be at a sufficiently low value when the slasher is again started provision is made upon the deenergization of relay Bill to reduce the setting of the transmission by ener gizing the slow field 53b of motor 43 for a short while. This is accomplished by energizing a time delay relay it through the line we when the upper bar of the switch member iilla closes that line. A circuit from the transformer through line 88, field 432), lines tilt, till, switch ltd, line W9, push buttons 9i, 9d and line tit bacls to the transformer is then completed. Motor #38 then runs in a direction to reduce the transmission setting until a bimetallic element it lc forming part of relay 584, is heated sumciently for its upper end to move to the right enough to open the switch Hi8. c

Upon restarting the slasher the shipper bar B6 is shifted to place belt 32 on the fast pulley 3i.

This moves switch :36 back. to its position of Fig.

3 to energize the relay lfli, and replace the full value of the resistance it in the bridge circuit. Current builds up slowly in the relay lili so that before the switch member this has moved to its upper position to close the circuit to relay M3 the yarn that has been on the drying drums during the time the slasher was stopped has been removed. Thereafter the speed oi the slasher is controlled in accord nice with the reelsture content of the yarn as the interrupter switch ti is closed.

Manual operation of the speed changing motor 53 may be performed at any time by pressing button to slow down the speed of the slasher and by pressing button ti to speed. it up. If it is desired to entirely remove the automatic control of the slasher speed the switch Mil in series with the interrupter 66 may be manually opened. thus breaking the common lead iii? to the control instrument M.

A short summary of the operation oi the system will now be given. When the slasher is at rest the switch member 416 will be bridging lines 91 and the pen carriage ltd wiil be at the dry end of the instrument holding switch tilt open so that steam under low pressure is admitted to the drying drums. The relay i166 has been energized long enough so that switch tilt is open and relay iii-3 is deenerglzed so that switch 95 is open. Therefore, the set ing oi the transmission M can only be changed manually by push buttons at and 95.

Upon moving the shipper rod l t to start the slasher the switch member is moved to its position of Fig. 3 and the instrument ivi immediately starts to measure the moisture content of assess? the yarn. By the time the yarn that was on the slasher drums during the stopping period has been removed current has built up in relay m sufficiently to move contact member lflla to its position of Fig. 3 to energize relay I03 and close switch 85. Thereafter the instrument controls the slasher speed and moisture content of the yarn by energizing the motor 43 for rotation in the proper direction.

Upon stopping of the slasher, switch 46 shunts out part of resistance 18 oi. the measuring circuit and deenergizes the relay NH. The effect of the latter is to immediately deenergize relay I03 to open switch 95 and to close a circuit through field 43b of motor 43 to run that motor in a direction to reduce the setting of the transmission. Simultaneously with the last operation the coil of relay I04 starts heating up and in a few seconds causes bimetallic strip iMa. to open switch I08 and stop motor43. The system is now again in its original condition.

The wiring diagram shown in Fig. 4 is similar in most respects to that shown in Fig. 3. Current is supplied from the line through a switch III, that when opened shuts down the entire system. Connected across the line is the switch 48 and the coil of a time delay relay H2, that is designed to open quickly and close a predetermined time after its coil is energized. Upon opening of switch 46 as the slasher is stopped the lines 81 are bridged, as was done in the embodiment of Fig. 3, to force the pen to move down scale and open switch Hill to reduce the steam pressure in the drying drums.

The interrupter switch 6| is also in this embodiment operated by the slasher so that the interrupting periods will be based upon the speed of the slasher rather than upon an arbitrary time. This has the obvious advantage that control impulses may be given the transmission speed control motor 43 more or less frequently according to the requirements of the process so that the instrument M can detect the full effect of a speed change before a subsequent change is made.

In this embodiment the fields of the motor 48 are shown provided with limit switches H3 and H4 that may beset at a point to limit the maximum and minimum'speeds oi the slasher. It is noted that the motor ofFlg. 3 may also be provided with similar switches if desired.

In the operation of this embodiment the switch ill is closed and the shipper rod is moved to a position to close switch 46 and start driving the slasher. A short time, depending upon the amount of yarn on drums 6 and 5, after the slasher is started relay H2 will close its contacts H5. Thereafter as the moisture content oi the yarn differs from that for which the instrument is set to maintain the fields 63a or 311 of motor 43 will be energized to change the setting of the transmission. After each control period the interrupter switch ti will be opened for a length of time depending upon the speed of the slasher so that the iull effect of the speed change may be determined before a subsequent change is made. The motor it may be rotated in either direction at any time by the manual operation of switches at or 99.

In the embodiment of the invention just described it was assumed that the slasher was driven from its individual driving motor 36. In some textile mills, however, it is customary to drive several slashers from a single motor by means of a common shaft. When this is done there will be a variation in speed of the remainlog slashers due to the load change when one of them is taken oft or the line. ouch a speed change of the driving shaft of the transmissions will cause a change in the speed of the slasher driving drums and 'therctor t the mele ture content of the yarn in order to overcome this obviously undesirable condition 1 have provided a means to compensate the speed of driven shaft 38 0! the transmissions for variations in speed of the driving shaft Referring to Fig. a, there is shown one com pensating unit in detail. to be understood that a similar unit may be use tor each of the slasher control systems, or a single unit, with proper connections, may be used for all of the slashers driven by the same shaft. in that figure there is shown a shaft Mtthat is driven by any suitable means, which shaft serves to drive the transmission units of plurality of slashers. Attached to the shaft is a hovel gear iiti that through a similar gear drives the shaft ill of a fiy-ball governor. Fixed to the lower end of shaft H1 is a collar lid and slidably mounted near its upper end is a collar Mil that is normally forced upward by a, spring ltd and is moved downwardly by the halls tilt as the shaft Ill increases in speed. Five-tally attached to the collar H9 is a lever 1122 whose opposite end is pivoted on a collar [123 that is adjustably secured in position on a support i12 extends parallel to the shaft ill. As the lever G22 moves clockwise and counter-clockwise around its point of attachment to the collar i253 due to slowing down or speeding up of the shaft iii a result of a change in load thereon, a three-armed lever 02$, pivoted at W, is moved accordingly due to a connection between on the lever i126 and a slot l22a in the lever Control of the transmission adjusting motor 43 from movement of the lever is obtained by means of a contact M8 on one of the lever I25 and contacts i225 B35) are supported on a movable bloct: ifii. "lice blocl: is mounted for sliding movement in the stationary bearings I32 and is provided on. one of its faces with a rack that is by a pinion is driven through a .c clutch comprising driving disc lilla and driver also which take the form of elec' cmagnetic from the motor 43 as it rotates. The third arm of lever H5 is formed as a pointer that cooperates with a scale Ht which may" he provided with calibra= tilosn marks corresponding to the creed of shait In the operation shait l is dllV- ing all of the slashers that connected When one of the slashers stopped the load on the shaft will be reduced so will tend to speed up. This will cause E'JGVGi'XlOi balls tilt to move further apart and move collar M9 down wardlyi to rotate lever H82 C'Olll'iliGE- ClGCYKV/lSG around its pivot on collar 623, which movement will rotate lever 625 counties-clockwise to bring contact I28 into with contact 68%. The contact is connected to one side of the line by a. condiictor includes the winding oi the magnet in clutch c b, and contact tilt) is connected to the lin 2;; from the in strument M to the slow v of the motor G3, so that upon engagement oi contacts the motor 43 is energized for rota on in. a direction to slow down the shaft 536 oi the transmission. Motor 43 will continue run until the hiccl; lill has been moved downwardly enough by the pinion m, driven by the clutch from motor t3,

to open the contacts F28 and At this time the shaft 36 of the transmission is running at the same speed that it was prior to the time the slasher was disconnected from shaft M5.

It will-be obvious that when the slasher that was stopped is again started the increased load will tend to slow the shaft H5 down. This will initiate an operation opposite to that just described to bring contacts 828 and 529 into engagement to energize field 53m of motor 63. When the speed of shaft 36 has been corrected to compensate for the change of speed of shaft M5 the contacts 828 and 62?} will be separated by upward movement of the block 53d. The initial aiustment of the collar 823 along support i2 5 may be changed as desired so that the apparatus may be adjusted for different normal speeds of the shaft M5. The normal speed of shaft H5 may be varied in any suitable manner to take care of diflerent types of yarn on the slashers.

As the motor 63 is energized by the instrument M the position of contact carrying block. I35 will not be altered since the clutch liif'ia, i331; is energized only when a circuit is closed through contact H8 and one of contacts 625! or 93d As has previously been stated various other factors besides the speed of the drying drums enter into the drying of the yarn, and at times it may be desirable to control others of these factors in addition to or'in conjunction with the speed of the drums.

In th operation of a slasher considerable steam rises from the size boxes and the yarn and the amount of drying obtained depends in part upon the amount of dry air pulled past the yarn by means or the hood 2b and the exhaust fan 2'6. By controlling the speed of this fan the drying efiect on the yarn by the drums l and ii can be varied. Such an arrangement is shown in Fig. 7 in which a variable speed motor 28a is used to drive the exhaust fan 27!. The speed of the motor 28a may be varied by moving a contact i236 along a resistance M35 in the motor circuit. This contact is moved by a reversible motor 536 that is in parallel with and energized simultaneously with the energization of transmission adjusting motor 63 as contact 86 in the instrument M engages either of contacts tile or set.

In this embodiment the arrangement is such that ii the instrument M indicates that the yarn is too dry the motor 33 will be rotated in a direction to speed up the drums d and i5 and the motor i135 will at the same time be rotated in a direction to shift th 'contact H36 to the right along the resistance i235 and slow down the fan motor 28a. In this manner a double effect is applied to the drying operation and it may not be necessary to vary the speed of the drums as much as when the latter is alone used to control the drying. This embodiment also has the added advantage, as do other embodiments to be described below that the slasher may be run more nearly at its full speed at all times.

In Fig. 3 there is shown another means for accomplishing the same result. Instead of varying the speed of the fan 2?! a damper Hill in the exhaust duct is opened or closed to vary the volume of exhaust air. The damper till is formed on one side of its lower end as a rack that meshes with a pinion its driven by a reversible motor M39. The motor 089 is also energized by the instrument M along with the motor 53. The arrangement is such that as the motor 33 is enerized tor rotation in a direction to slow down assess? the drums the motor 339 will be rotated in a direction to lower the damper i3? and permit more air to be drawn past the yarn. In this manner the drying process is increased in response to a measurement showing that the yarn was too moist.

As is well known, the drying efiect of a cylinder depends upon its temperature, which i in turn dependent upon the steam pressure within the drying drums. While it is generally desirable to maintain the temperature of the drying drums constant and vary their speed as has been above described, there are times when it may be of advantage to vary the steam pressure in the drums in conjunction with their speed. Such an arrangement is diagrammatically shown in Fig. 9. The recording pressure controller 98, which has been described above is used to regulate the valve ill and thereby the pressure in the drums (l and E5, may well have the control provisions described and claimed in Patent 2,125,081 issued to C. B. Moore and is now in extensive commercial use. An instrument of that type has provisions for adjusting the pressure which is to be maintained to different values, and while such an adjustment may be made manually it is, for purposes of this invention, more convenient to make by means of a small reversibl electric motor that is energized by the instrument M when motor 63 is energized.

In the operation of an interlock system of this type as the moisture content of the yarn is, for example, low the instrument M will energize motor 33 for rotation in a direction to speed up the drying drum and will simultaneously energize the control setting motor in the instrument iii in a direction to lower the controlpoint thereof and reduce the steam pressure in the drying drums. Because of the fact that both the speed of the drums and the steam pressure therein are varied it is necessary to maize only small adjustments of each in order to obtain the necessary correction in the moisture content of the yarn.

' Instead of varying the steam pressure in the drying drums along with their speed said pressure variations may be used only after the speed change mechanism has reached the limit of its movement. In this manner the range oithe system may be extended appreciably. An arrange-- ment for doing this is shown. in Fig. 10 wherein the motor driven valve Mb is used to control the pressure in the drums instead 01 the valve ill previously described. The opening of valve 869 is adjusted by means oi a segmental rack ili and a pinion its that are driven by a reversible motor MB. This motor is supplied from one side or the line through an interrupter E 365, through switches M5 or M6 to the other side of the line and is so arranged that when switch M35 is closed the valve will be moved in a closing direction and when switch is closed the valve will be moved in an opening direction. The interruptor Hill may be operated to close the circuit at equal intervals or time, but is preferably driven from the shaft li along with the interrupter 59. If desired the support so of the interrupter 50 may have a second switch attached to it, which second switch. forms the interruptor MG.

In the operation or: this embodiment as the speed control motor 33 is adjusted a lever id? is moved thereby in such a manner that as the motor reaches its maximum or minimum positions,.respectively, the switches llll or MS will be closed to energize motor M3 to adjust the aerate? opening of valve i ili. If, for example, the yarn is unduly moist as it passes the measuring roller a the instrument M will cause motor $3 to be energized in a direction to slow down the speed oi the drums 4i and 5, at the same time moving lever Nil clockwise. After the motor 433 has been run to adjust the transmission M to its minimum speed limit, the lever Ml will close switch M5 to energize the motor M3 for rotation in a directionto open the valve Mil. The motor, due to the interrupter HM will be run in steps to increase the steam to the drums only after a measurement has been made to show the effect oi a previous adjustment on the yarn. If an adjustment of the valve Md was such that the yarn is dried too much the motor li-i will be energized to slow down the transmission and the drums and at the same time will move lever i l'l counterclockwise to open switch Mil. Thereafter until the motor 43 has reached one or the other of its limits the steam pressure in the drying drums will be maintained at its new limit. In a like manner if the yarn is unduly dry the lever Hl'i on motor 43 will be moved counter-clockwise until switch I45 is closed. At that time motor M3 will be intermittently operated to reduce steam pressure in the drying drums,

Another method of controlling the moisture content of the yarn on a slasher is by simultaneously adjusting the speed of the drying drums and the speed of the spider fan 29. The air entering the fan to be blown over the yarn is usually heated by radiation from the larger drum 4 and, therefore, has an influence on the moisture remaining in the yarn, although such influence is generally less than that of the exhaust fan 2?. As shown in Fig. 11 the spider fan 29 is driven by a variable speed motor 2% that is supplied with current through a variable resistance M8 whose value can be changed by movement of the contact M9 therealong. This contact is moved in one direction or the other by a reversible motor 559 which is energized from the instrument 1M? dong with motor M3.

in operation if the yarn is too dry the motor &3 will be energized for rotation in a direction to speed up the drums and at the same time the motor idd will be energized for rotation in a direction to shift contact M9 to the right along resistance M8 and slow down the motor 2%. In like manner if the yarn is too wet the drying drums will be slowed down and motor iiitl will be energized in a direction to shift contact M9 to the left and speed up the motor 2% so that fan 29 will force more warm air over the yarn.

Still another interlock system that may be used to control the moisture content of yarn is shown in Fig. 12 in which the speed or the drying drums is controlled in conjunction with thetemperature of the size box. The temperature of the size has an influence on the amount of moisture remaining in the yarn by the time it reaches the drying drum 6. This is because a high temperature naturally induces more evaporation. As is shown in Fig. 12 the size box 3 is heated by an electn'c heater i5! whose heating effect is varied by moving the contact i522 along the resistance E53. The contact is adapted to be moved in the proper direction by means of a reversible electric motor I54 that is energized for rotation along with the motor it by the instrument M.

If the yarn is too dry the motor 53 is energized for rotation in a direction to speed up the drying drums and at the same time motor led rotated in a direction to move contact 652 upwardly along resistance iti to thereby reduce the temperature of the size. In a like manner it the yarn is too moist the drums Li and ii are slowed down and the size temperature is raised.

While I have described the regulation 01. the size temperature by the adjustment of an electric heater it will be obvious that a controller of the type shown at i i in Fig. 1 may be used if desired.

If that is the case the control point of the con-' troller it will be adjusted by an electric motor as was the control point of the controller III in Fig. 9.

In the above detailed description various means have been disclosed for controlling the drying process or yarn in a slasher. It will be understood that the various control instrumentalities may be used singly or with each other in other combinations than those disclosed if necessaryor desirable. It will be obvious that the addition of a control for one or more of the variables in the slashing process to any of the other controls in order to obtain a better product may be accomplished within the scope of my invention. Each of the variables in the process that is controlled cooperates with the others to produce a more uniform product, and those variablesthat are controlled together may be selected in accordance with the type of yarn being handled, the percentage of moisture that is to be kept therein and various atmospheric and plant conditions that afiect the process and cannot be controlled.

The term yarn that is used herein and in the appended claims is meant to include both natural and artificial threads such as cotton, wool, rayon etc.

Attention is also calleolto the fact that while the control system is described for use in connection with a slasher for drying yarn that the same system is equally adaptable for use with systems for drying any type of wet material in which the speed of the material passing the drying means may be changed.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form or" the apparatus disclosed without departing from the spirit or" my invention as set forth in the appended claims, and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by letters Patent is:

1. In a slasher control system wherein the slasher is provided with heated drying drums over which the yarn to be dryed passes and is provided with a variable speed driving mean for the drums, the combination of means to measure the moisture content of yarn passing the drying drums, means to adjust the variable speed driving means controlled by said measuring means, and means actuated in response to variations in the speed of the drums to interrupt the operation of said means to adjust the variable speed driving means.

2. In a slasher a rotatable drying drum, means to supply a heating medium to said drum. variable speed drive means for said drum, means to measure the moisture content of yarn passed over said drum, means controlled by said measurlng mean to adjust said speed varying means, means actuated in response to variations in the speed of the drum to render said adjustment intermittent means to stop said drum and means operated by said stopping means to adjust said supp means to reduce the heating medium in aid drum.

3. In a slasher provided with a drying drum, driving means and a supply of a heating medium therefor, means to vary the speed of said drum, means to stop and start said drmn and means controlled by said stopping and starting means to prevent operation of said speed varying means until a predetermined period aiter the starting of said drum.

4. In a web drying system, a heated drum over which the web is led, means to measure the moisture content of the web after it ha been dried, means to vary the speed or said drum controlled by said measuring means and means actuated in response to variations in the speed of the drum to operate said speed varying means intermittently for periods of time depending upon the speed of the drum.

5. In a slasher control system wherein the slasher is provided with a drying drum over which the yarn to be dryed is passed and with a variable speed mechanism to drive the drum, the combination of means to measure the moisture content of the web after it has passed over the drum, means responsive to said measuring means to adjust the variable speed mechanism, and means actuated in response to variations in the speed of the drums to interrupt the operation of said means to adjust the variable speed mechanism.

6. In a control system drying means for a web, drive means for said drying means, means to' vary the speed of said driving means and therefore the speed with which the web passes said drying means, means to measure the moisture content of the web, means to adjust said speed varying means in response to said measuring means and automatic means actuated in response to variations in the speed oi the drum to interrupt the operation of said adjusting means so that the speed of the web i changed in steps.

7. A slasher control system for drying a web comprising in combination with a slasher having drying drums, a supply of heating medium therefor, variable speed driving means for said drums, means to stop said driving means and means operated thereby to reduce the speed setting of said driving means regardless of the moisture content of the web.

8. The method of controlling a slasher havinga drive means which comprises the steps of measuring the moisture content'oi yarn that has been dried by the slasher, controlling the speed or" said drive means for said slasher in response to said measurements, and interrupting the speed controlling operation in timed relation to the speed of the slasher.

9. In a control system for a drying machine having a drying drum and variable speed means to drive the drum and in which there is a manually movable means to disconnect the variable speed means from it source of power, the combination of mechanism operated by the manually movable means when the variable speed means is disconnected from its source of power to positively prevent an increased speed setting of the variable speed means, and means to delay any change in the setting of the variable speed means when it is again connected to its source of power.

iii. In a drying system for drying yarn having is access? a drying drum and an exhaust hood positioned above the drum and wherein there is provided a variable speed means to drive the drum and an adjustable means to control the exhaust from the hood, the combination of means to measure the moisture content of the yarn being dried, i and means controlled by said measuring means to change the speed of the drive means and to adjust the adjustable means in a sense to correct variations in the moisture content of the yarn.

11. In a web drying machine having a drying portion, means to move the web therethrough and means to exhaust moisture laden air from adjacent thereto, moisture determining means responsive to the moisture content of the web leaving said drying portion, means controlled by said moisture determining means to vary the effectiveness of the exhausting means and the speed with which the web is moved past said drying portion, and means actuated in accordance with the speed of the web to intermittently interrupt said controlled means.

12. In a drying machin a. drum over which material to be dried is moved, a fan to force air over said material as it leaves the drum, variable speed means to drive said drum and variable speed means to drive said fan, means operated in response to variations in the moisture content of the material being dried to simultaneously vary both said driving means to compensate for changes in the moisture content of the material.

13. In a drying machine, a drum over which material to be dried is passed, means to supply a heating medium to said drum and means to drive said drum, moisture determining means responsive to the moisture content of the material being dried, means actuated by said moisture determining mean to vary the speed of said drum and to vary the supply of the heating medium therefor, means to detect variations in speed of the drum and means operated by said last mentioned means to operate said means actuated by said moisture determining means intermittently for periods depending upon the variations in speed of the drum.

14. In a system to dry a web in which there is provided a drying means for a web, a means to move the web, a means to vary the speed of the moving means and means to stop and start the speed varying means, the combination of moisture measuring apparatus to adjust the speed varying means in response to the moisture content of the web that has passed the drying means, and means to withholdoperation of said measuring apparatus until a predetermined period after the speed varying means has started.

15. In a drying machine a rotatable drying drum, means to drive said drum and means to vary the speed thereof, means to top the rots.- tion of said drum, means to reduce the setting of the speed varying means responsive to operation of said stopping means and means to prevent operation of the speed varying means for a predetermined time after the drum has been started.

16. In a slasher having a drying drum and a. hood extending thereover, an exhaust duct for said hood, a variable speed fan to draw air from over said drum through said duct, variable speed means to drive said drum, variable speed drive mean for said fan, means to measure the moisture content of yarn passing over said drum, and means to adjust said variable speed drive means to speed up the drum and slow down said fan controlled by said measuring means in response [to a measurement indicating that the yarn is too 17. In a slasher control system in which a slasher is provided with a rotatable drum over which yarn to be dryed is passed and having drive means for the drum whose speed may be varied between given speed limits and having an adjustable means to supply a heating fluid to the drum, the combination of meansto measure the moisture .content of the yarn, mechanism responsive to said last mentioned means to vary the speed of the drive means for the drum' between its given speed limits, and ineaiis controlled by said mechanism-and operate upon the reaching of one ofthe speed ,limits of the drum to adjust the means to supplythe heating fluid to the drum.

18. Apparatusof the type set forth in claim 17 in which means is provided to render the opera- ,tion of said supply means discontinuoua 19. In a slasher control system having rotatin; drying drums and a supply of steam there- !or, variable speed means to drive said drums, measuring means responsive to the moisture content-of the material dried to vary the speed of said drums between given speed limits, means operated by said variable speed drive means to operate said speed varying means intermittently, means controlled by aid variable speed drive means and operated in response to the reaching a speed limit of,.said drum to regulate said supply of steam, and means to operate said regulating means intermittently.

10. In a system of slasher control, common means at times varying in speed to drive a plurality of slashers, a variable speed driving means individual to each slasher interposed between said common means and the Slashers, means respousive to said common means when it changes in speed to adjust said variable speed, means whereby the speed of the slashers is not altered as the speed of the common means changes, means to measure the moisture content of yarn being dried and other means controlled by the in speed to compensate for the variations in drying eil'ect of each dryer due to said speed changes, and means responsive to the moisture content of the material being dryed to also adjust the individual drying effect of each dryer.

22. Ifhe combination of claim 21 including means to render the operation of the last means intermittent.

23. In a control system having a drying machine with drying rolls for drying a web passing thereover, driving means for the rolls, an electric motor to vary the speed of the driving means and circuit connections between the electric motor and a source of energizing current, the combination of means responsive to a condition of the web which is indicative of the moisture content thereof, and an interrupter driven by the driving means for controlling the circultconnections jointly with said means responsive to the condition of the web.

24. In a system of slasher control, common means at times varying in speed to drive a .plu-

rality of slashers, individual means to drive each slasher from said common means, mechanism responsive to changes in speed of said common means, mechanism responsive to changes in moisture content of the material being .acted upon by said slashers and means jointly operated by each of said mechanisms to vary the drying eil'ect of said slashers to maintain the moisture content of the material being acted upon constant.

25. In a system of drier control the combination of means to support and dry material, drive means for said supporting and drying means, measuring means to measure the value of a condition of the material which is indicative of the moisture content thereof and which varies as means to stop the drums, and means operated.

the material passe through the drier and which is proportional to the treatment received, means actuated by said measuring means to vary the speed of said drive means, and means controlled bysaid drive means and actuated in response to variations in the speed of the drying means to interrupt the operation of said speed varying means.

26. In a dryer control system wherein there is a dryer having a plurality of drying drums that are driven by a variable speed driving means and means to vary the speed thereof, and wherein th drying drums are supplied with a heating medium through a regulating means, the combination of means to measure the moisture content of the web, means controlled by the driving means to adjust the speed varying means in steps proportional to the speed of the drums, and means controlled by said last mentioned means and operated upon stopping of the drying drums to adjust the regulating means in a direction to reduce the supply of heating medlum.

27. In a web drying machine, a plurality of drying drums, variable speed driving means, for said drums, means to adjust said driving means, mean to measure the moisture content of a web passing over said drums and operative to adjust said adjusting means in accordance with the moisture content of the web, means controlled by said driving means to render the adjustment tlon. means to synchronize the operation of the adjusting means with the speed of the drums,

by, said last mentioned means to reduce the drying effect of the drums while they are stopped.

28. In a control system for a drying machine having a plurality of drums that have a primary drying eilect on a web to be dried that is passed over them, a means to drive the drums and a means to vary their speed to vary the time the webis in contact with the drums and accordingly vary the primary drying effect of the drums on the web and wherein there is a means to provide a secondary drying sheet on the web and a means to vary the effectiveness of the secondary drying effect, the combination of means to measure the moisture content of the web, and

varying in speed to drive a plurality of slashers,

a variable speed driving means individual to each slasher interposed between the common means and each slasher, means responsive to said common means when it change; in speed to adjust said variable speed means whereby the speed of the lashers is not altered as the speed of the common means changes, means to provide a drying eflect on the web secondary to that of the drying drums, means to measure a condition of the web that i'sindicative of the moisture content of the web, and means operated by said last mentioned means to also adjust said variable speed means and to simultaneously adjust said mean which provides the secondary drying eiiect,

30. In a system of slasher control in which each slasher has a plurality of drying drums over I which a web to be dryed passes, the combination comprising common means at times varying in speed to drive a plurality of slashers, a variable speed driving means individual to each slasher interposed between the common means and each slasher, means responsive to said common means when it changes in speed to adjust said variable speed means whereby the speed of the slashers is not altered as the speed of the common means changes, a fan operative to produce a drying effect on the web secondary to that produced by the drying drums, means operative to vary the drying eflect produced by said fan, means to measure the moisture content of the web, and means operated by said last mentioned means to also adjust said variable speed means and to simultaneously adjust said means operative to vary the drying effect of the fan.

31. Ina system of slasher control in which each slasher has a plurality of drying drums over which a web to be dryed passes, the combination comprising common means at times varying in speed to drive a plurality of slashers, a variable speed driving means individual to each slasher interposed between the common means and each slasher, means responsive to said common means when it changes in speed to adjust said variable speed means whereby the speed of the slashers is not altered as the speed of the common means changes, a hood located over said drying drums, an exhaust duct for said hood, a variable speed fan to draw air from over said drums through said duct, variable speed drive means for said fan, means to measure the moisture content of the web passing over said drum, and means to speed up the drum and slow down said fan controlled by said measuring means in response to a measurement indicating that the web is too dry.

32. In a system of slasher control in which each slasher has a plurality of drying drums over which a web to be dryed passes, the combination comprising common means at times varyingin speedto drive a plurality of slashers, a variable speed driving means individual to each slasher interposed between the common means and each slasher, means responsive to said common mean when it changes in speed to adjust said variable speed means whereby the speed of the slashers is not altered as the speed of the common means changes, means to measure the moisture content 0! the web, mechanism responsive thereto to adjust said variable speed driving means between given limits, adjustable means to supply a heating fluid to said drum, and means operated in response to the reaching of one of the limits oi is said variable speed driving means to adjust said supply means.

33. In a system of slasher control in which each slasher has a plurality of drying drums over which a web to be dryed passes, the com.- bination comprising common means at times varying in speed to drive a plurality of slashers, a variable speed driving means individual to each slasher interposed between the common means and each slasher, means responsive to said common means when it changes in speed to adjust said variable speed means whereby the speed of the slashers is not altered as the speed of the common means changes, a fan to force air over the web as it leaves the drum, variable speedmeans to drive the fan, means operated in response to variation in the moisture content of the web to simultaneously vary both said variable speed driving means and variable speed means to drive 7 the fan to compensate for changes in the moisture content of the material.

34. In a system of slasher control in which each slasher has a plurality of drying drums over which a web to be dryed passes, the combination comprising common means at times varying in speed to drive a plurality of slashers, a variable speed driving means individual to each slasher interposed between the common means and each slasher, means responsive to said common means when it changes in speed to adjust said variable speed means whereby the speed of the slashers is not altered as the speed of the common means changes, means to measure the dryness of the web after it has passed over the drums, means responsive to said measuring means to vary the speed of said driving means, and means actuated in response to variations in the speed of the drums to interrupt the operation of said speed varying means.

35. In a drying machine, the combination of a drying drum, an exhaust hood over said drum, variable speed driving means for said drum, adjustable means to control the exhaust from said hood, means to measure the moisture content of the web that has been dryed, means operated by said measuring means to adjust said variable speed driving means and said adjustable means to compensate for variations in moisture in said web, a manually movable means to disconnect said variable 'speed driving means from its source of power, mechanism operated in response to the disconnecting of said variable speed means from its source of power to positively prevent an increased speed setting of said variable speed drive means, and means to delay temporarily any change in the setting of the variable speed means upon the connection thereof to its source of power,

36. In a slasher comprising a rotatable drum over which yarn is passed, the combination of means to measure the moisture content ofsaid yarn, variable speed driving means for said drum that is operable between given speed limits. adjustable means to supply a heating fluid to said drum, means controlled by said driving means and 0 rated in response to the reaching of one of the speed limit of said variable speed driving means to adjust said supply means, means to render the adjustment of said variable speed driving means discontinuous, means to stop said variable speed driving means, and means operated by said stopping means to reduce the speed setting of said driving means re-' gardless oi the moisture content of the yarn.

which material to be dried is moved, the co bination comprising a fan to force air over said material as it leaves the drum, variable speed means to drive said drum and variabl speed means to drive said fan, means operated in response to variations in the moisture content of the material being dried to simultaneously vary both said driving means to compensate for changes in the moisture content of the material, means controlled by said variable speed means and actuated in response to variations in the speed of the drum to interrupt the operation of the variable speed means driving said drum, means to stop said variable speed driving means for said drum, and means operated by said last mentioned means to reduce the speed setting of said driving means regardless of the moisture content of the web.

38. In a system of slasher control in which each slasher has a plurality of drying drums over which a web to be dryed passes, the combination comprising common means at times varying in speed to drive a plurality of slashers, a variable speed driving means individual to each slasher interposed between the common means and each slasher, means responsive to said common means when it changes in speed to adjust said variable speed means whereby the speed of the slashers is not altered as the speed of the common means changes, means to provide a drying effect on the web secondary to that of the drying drums, means to measure a condition of the web that is indicative of the moisture content of the web, means operated by said last mentioned means to also adjust said variable speed means and to simultaneously adjust said means which provides the secondary drying effect, and means actuated in response to variations in the speed of the drums to interrupt the operation of said variable speed driving means. 39. A web drying machine having a plurality of drying drums over which a web to be dryedis passed, said drums having a primary drying eil'ect, means to drive said drums, means to vary the speed of said driving means to thereby vary the time said web is in contact with the drums and accordingly to vary the primary drying effect of said drums on said web, means to provide a secondary drying effect on said web, means to vary the eilectiveness of said last mentioned means, means to measure the moisture content of said web, means actuated by said measuring means to adjust said speed varying means to vary the primary drying effect and to adjust said means varying the eirectiveness oi the means for providing the secondary drying eil'ect, and mean actuated in response to variations in the speed of the drums to interrupt the operation of said speed varying means.

40. In a drying machine including a drum over which a web of material is to be passed, the combination comprising means to drive said drum, means including a supply line for a heating medium for said drum, a valve in said supply line, means to measure the moisture content of the web being dryed, mechanism responsive to said measuring means to vary the speed of said driving means between given speed limits, means controlled by said mechanism and operated in response to reaching one of said speed limits to adjust said valve in a direction so that the eil'ect of the heating medium will add to that of the drive means to return the moisture context of the web toward a given value.

41. In a slasher comprising a rotatabl drum over which yarn is passed, the combination 0 means to vary the speed a; said drum, means to measure the moistur content of said yarn, mechanism responsive thereto to vary the speed of said drum between given speed limits, a pipe through which steam to heat said drum is passed, a valve in said pipe, means to operate said valve, means operated by said mechanism and operated in response to the reaching of one 01' the speed limits of said speed changing means to adjust the opening of said valve, and means to render the operation of said valve discontinuous.

42. In a slasher, the combination comprising a drying drum, means to drive said drum, means to vary the speed of said driving means, means to measure the moisture content of yarn passing said drum, means to adjust said speed varying means controlled by said measuring means, and means connected to said driving means for interrupting the operation oi said speed varying means.

43. A slasher control system wherein there is provided a drying drum with variable speed means to drive the drum and means to disconnect the variable speed means from its source of power and a supply of heating fluid for the drum, the combination of measuring means responsive to the moisture content of the yarn that has passed over the drum, an indicating member operated by said measuring means, means operated by the disconnecting means upon disconnection of the driving means from its source of power for controlling said measuring means to move said indicating member, and mechanism operated by said indicating member at a predetermined point in its path to reduce the supply of heating fluid to the drum.

ANmR E. KROGH.

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