US2686280A - Electromagnetic piston pump - Google Patents

Description

1954 H, w. STRONG ETAL 2,686,280 ELECTROMAGNETIC PISTON PUMP Filed Oct. 25, 1949 3 Sheets-Sheet 1 INVENTORS WILLIAM CTRETH EWEY, JOHN B KLINGEL AND BYHERBERT W. STRONG.

Aug. 10, 1954 w. STRONG ETAL 2,686,280

ELECTROMAGNETIC PISTON PUMP Filed Oct. 25, 1949 3 Sheets-Sheet 2 INVENTORS. WILLIAM QTRETH EW EY.

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8" 10, 1954 H. w. STRONG ETAL 2,686,280

ELECTROMAGNETIC PISTON PUMP Filed Oct. 25, 1949 3 Sheets-Sheet 3 23 21 22 2 INVENTORS.

WILLIAM CTRETH EWEY,

Patented Aug. 10, 1954 ELECTROMAGNETIC PISTON PUMP Herbert W. Strong, Cleveland Heights, William C. 'lrethewey,

Cleveland,

Garfield Heights, Ohio Application October 25, 1949,'Serial No. 123,416 Claims. (01. 318-125) This invention relatesto pumps, and more particularly to an electromagnetic piston pump especially adapted for the circulation of fluids (liquid or gaseous) which are corrosive or otherwise difiicultto handle.

In order to illustrate the principles-and the advantages of the invention, they may be considered in connection with the problem of pumping corrosive fluids such as acids and the like, extremely poisonous or highly inflammable fluids, and fluids difiicult to contain, such as heat transfer liquids.

.By the nature of these fluids, conventional pumps, either of the piston type or of the centrifugal type, are unsatisfactory and dangerous because the pump chamber must be provided with a gland for a piston rod, drive shaft, .or the like, thus presenting a problem of leakage. Moreover, by the nature of such conventional pumps they are not well adapted to .manufacturefrom chemically inert materials such as glass, rubber, and phenolic condensation products.

The most nearly satisfactory pumps for such conditions have heretofore been of the diaphragm type. These, however, are far from satisfactory because of their low capacity relative to the size of the pump and the danger of failure of the diaphragm in service.

Since the pump of the invention requires no external motor and .may easily be made of waterproof construction, it is also suited for sump installations where the pump is submerged.

This invention provides a solution to the problems outlined above byproviding a pump in which there are no parts which flex during operation, in which the parts exposed to the fluid may be of material of any desired chemical characteristics for resistance to corrosion, and in which no moving part enters or leaves the confined fluid. More specifically, the invention involves a pump in which a floating piston is reciprocated electromagnetically. The invention .also involves novel electrical systems by which the movement of the piston is effected.

In its preferred form, .the invention embodies but one moving part, other than the valves, which may be simple check Or flapper valves such as have previously been employed and present no problem. This moving part is a piston freely reciprocating in a pump cylinder, electromagnetically coupled with solenoids disposed around the cylinder energized so as to reciprocate the piston, which constitutes an armature for the solenoids. The solenoids are coupled to a power circuit for alternate energization, .the power circuit being controlled by means sensitive to the position of and John B. Klingel,

the piston so that as it reaches each end of its stroke the appropriate solenoid is energized to draw it to the other end of the stroke. This sensitive means is preferably a coil at each end of the cylinder which is inductively coupled to the driving coils by the piston, thus providing energy, which, through an appropriate relay system, controls the flow of power to the motor coils. The pump of the invention is in some respectssimilar to those disclosed in Van Depoele Patents 458,473 and 461,295, but differs greatly therefrom in the means for energizing the solenoids and in adaptability to corrosive fluids.

The nature of the invention and the objects and advantages thereof may be more clearly understood by reference to the following description of the preferred embodiment thereof, and to the drawings in which Fig. 1 is a. longitudinal section of a pump in accordance with the invention; Fig. 2 is a diagram of one form of relay or control circuit for the ump; and Fig. 3 is .a diagram of a second form of control circuit.

The preferred form of pump, illustrated in Fig. 1, comprises a cylindrical body I! of plastic formed with a central bore or cylinder l 2 within which a piston or plunger 13 reciprocates freely. The piston is formed of a bundle of soft iron wires 14 imbedded in and coated over the entire exterior surface by a plastic material [5. This material may be poured over a bundle of the wires in a fluid condition, thus filling the interstices between the wires serving as a binder. The plastic material also covers the entire outer surfaces of the piston, which result may be obtained by pouring the material into a mold which is removed after it has solidified, or by spraying the outer surface of the piston. The piston thereafter may be turned or otherwise finished. Magnetic material in other forms than wire may be used. Preferably, the diameter of the wires is less than that shown in the drawings, the size being exaggerated for clarity of the drawings. The circumferential layer of non-magnetic material should be as thin as practicable to reduce the air gap between the iron core and the propelling or motor coils. These coils 2i and 22 are enclosed within the plastic body I l which body comprises a cylinder wall it. The body also encloses pick-up or control coils 23 and 2% adjacent the end thereof. As will be noted, all the coils are concentric with the cylinder. They may be preformed and then impregnated with the plastic in this condition, or, if desired, the coils may be wound in place and the outer shell I], which encloses thecoils and is desirable from the standpoint of protection of the coils may be added, or other assembly methods may be used. The plastic body and plastic shell for the piston are desirable for elimination of exposed metallic parts which would be harmed by the fluid acted upon by the pump; however, it will be apparent that from the structura1 standpoint other materials could be used. The cylinder wall It should be of a non-magnetic material and one not subject to corrosion by the fluid. The remainder of the body 2!, if protected from the fluid, may be of a material which is not corrosionresistant.

Annular disks 23 of magnetic material serve to shield the control coils from the adjacent motor coils and thus prevent excessive coupling between these coils when the piston is not within the control coils.

It will be noted the piston 13 is of somewhat greater length axially of the cylinder than the.

motor coils 2i and 22, and, if either coil is energized, it will exert a force on the piston tending to center it in the field of force of the coil and thus pull it toward the end of the cylinder. Thus, if the coils 2i and 22 are energized alternatively, the piston will be reciprocated.

The pump also comprises suitable valves of the check valve type to control fluid flow into and out of the chambers H9 at each end of the cylinder. These valves are shown schematically, since the invention does not depend upon the specific type or location of these valves. As illustrated, the pump comprises an intake 50 which divides into branches 5! and 52 coupled to intake valves 53 and 54. These valves are coupled to conduits 55 and 56, respectively, provided with branches 51 and 58 for connection to the chambers I9. The conduits 5t and 51 also communicate with outlet valves 59 and 60 which discharge through conduits 6! and 62 into the pump outlet 64.

Suitable means must be provided to couple the conduits 51 and 58 to the pump, and the preferred arrangement comprises flanges 63 secured to the ends of the body by cap screws 61 and constituting heads for the cylinder. The flanges are provided with openings 68 within which a conduit may be secured in any appropriate manner; A gasket 10 is provided between each flange and the body and may extend within the cylinder so as to provide a buffer for the piston. The flanges 68 may be threaded or otherwise adapted for securing the conduits 51 and 58 to the flanges.

It will be apparent that the valves and conduits coupling them to the cylinder and to the inlet and outlet could be within the body of the pump, but the specific arrangement is not regarded as material to the invention, and it is preferable in some respects to mount the valves outside the coil housing or body I I.

It will be noted that each end of the cylinder with its valves constitutes a complete pump, and could operate alone. The double-ended arrangement is preferable, however, in that it eliminates the necessity for piston rings or packing and eliminates leakage, balances the load on the two piston strokes, and provides greater capacity for agiven size of pump at a given speed of operation.

A preferred form of control for the pump of the invention is illustrated in Fig. 2, in which the motor coils 2! and 22 and the control coils 23 and 24 are illustrated in aligned relation as in the pump. One line 25 of an A. C. power source is connected to a common junction of the two motor coils and the other line 26 of the A. C.

power source is connected through ignitron tubes 21 in back-to-back connection to a line 3| leading to the motor coil 2|. The A. C. line 26 is also coupled through ignitron tubes 28 to energize the line 32 leading to the motor coil 22. The line 26 is connected to the cathode 33 of one ignitron tube of each set, and to the anode or plate 34 of the other tube of the set, lines 3| and 32 being likewise connected to one anode and one cathode. The igniter 35 of each tube is con.- nected to the cathode through an individual secondary winding 35 of a saturable transformer 31 controlling tubes 21, or 33 controlling tubes 23. The transformers 31 and 38 include primary windings 29 connected in parallel to the A. C. power line. These transformers are of a wellknown type in which the transformer core may be saturated by passing direct current through a winding of the transformer, and, when the winding is thus saturated, the transformer action is reduced from its normal value to a relatively small fraction thereof. When the transformers are not saturated, the voltage induced in the windings 3c is sufficient to ignite the tubes 21 and 28, each tube thus conducting current during one half-cycle of the alternating current so that the motor coil 2! is continuously energized when the transformer 31 is unsaturated and the motor coil 22, likewise, when the transformer 38 is unsaturated. The saturating winding 39 of the transformer 31 may be energized by the current induced in the control coil 23, which is coupled to the saturating winding 29 through a fullwave rectifier M of the dry disk type or any other suitable rectifier. The saturating winding 40 in the transformer 38 is similarly energized by the pick-up coil 24 through the rectifier 42. The saturating coil 40 may also be energized from a secondary winding 43 of the transformer 31 through a full-wave rectifier and the saturating winding 39 from a secondary winding 44 of the transformer 38 through a rectifier 46.

The operation of this system may be described, assuming that the motor coil 2! is energized and is drawing the piston into the coil 23. Voltage induced by transformer action between the coils 2! and 23 passes through the rectifier 4|, energizing the saturating coil 39. The saturation of the core of the transformer 31 greatly reduces the voltage of the coil 36 so that the tubes 21 and 29 will no longer fire and cease to conduct current at the end of the half cycle, thus deenergizing the coil 2|.

While the transformer 31 is unsaturated, the saturating winding 40 of the opposing transformer is energized by the winding 43 through the rectifier 45, and thus tubes 28 are non-conducting and motor coil 22 deenergized. The saturation of the transformer 31 substantially deenergizes the coil 43, increasing the voltage on the igniters of tubes 28 and energizing the coil 22. The piston I3 is thus pulled to the right to ward the center of the coil 22 and couples it electromagnetically with the coil 24. E. M. F. induced in coil 24 rectified at 42 energizes the winding 40 and saturates the transformer 38, thereby rendering the tubes 28 non-conducting and deenergizing coil 22. It also deenergizes winding 44, and the transformer 31 is no longer saturated by this coil. The coil 2! then becomes energized, and the piston is shuttled to the left, completing the cycle.

The form of control just described is believed to be highly suitable, but it will be apparent to ho e Skilled in the art that many other forms of control having the same general characteristics may be employed in substitution to that described.

Fig. 3 illustrates a control system in which electron-is circuits are eliminated, the relay function being performed by saturable transformers and saturable reactors. in Figs. 2 and 3 are assigned the same reference numbers. saturable transformers I31 and I38 are similar to those of Fig. 2 except that a single output winding I36 is present instead of the two output windings 36 of the transformers of Fig. -2.

The transformers I31 and I38 are saturated by coils 3'9 and 40 energized from the control coils through rectifiers H and '42, and each trans former has a secondary winding 43 or 44 which energizes a saturating winding of the other transformer through a rectifier 45 or 46, as previously described. The A. C. line 25 is connected to both motor coils as before. The control of power between the line 28 and the lines 3| and 32 leading to the individual motor coils is effected in this instance by saturable reactors instead of ignitrons. The saturable reactor 8| is provided with a coil 83 in series with the motor coil 2I and the saturable reactor 82 is provided with a coil 84 in series with the motor coil 22. The saturating windings 85 and 86 of the reactors BI and 82 are energized by the secondary windings I36 of the saturable transformers I31 and I38, respectively.

saturable reactors of the type employed in this circuit are well known. When no current flows in the saturating winding 85 or 86, the reactor acts as a simple reactive impedance or choke, offering a relatively high resistance to passage of alternating current through the winding 83 or 84. By energizing the saturating winding, the core may be substantially saturated so that the impedance of the winding 83 or 84 is greatly reduced.

In view of the previous extended description of the operation of the circuit of Fig. 2, it is believed that no such extended description will be necessary for Fig. 3. In the device of Fig. 2, when the secondary windings 36 are energized the ignitrons coupled to them conduct current. Under the same conditions of non-saturation of the transformers I31 and I38, current induced in the windings I36 saturates the reactor 8| or 82,

thus, permitting an increase in current of the motor coil from an insignificant value to full energization. The parallel between the operation of the two circuits is so clear that further description is believed unnecessary.

It will be noted that reactors 8i and 82 are illustrated as saturated by alternating current. Reactors so saturable are available and may be used where the use of alternating current for saturation is desired. It will be apparent that the output of coils I36 could be rectified if it were desired to use reactors saturated by direct current.

It is also possible to control the pump by an electromagnetic relay system, but we believe that make-and-break contact devices are not capable of fully satisfactory operation.

We believe it preferable to control the power system by a device such as coils 23 and 24 or other means responsive to the piston at each end of the cylinder. It will be apparent, however, that control may be effected by a single responsive device at one end of the cylinder. For example, in Fig. 2, coil 24 and rectifier 42 could be omitted. Excitation of coil 23 would deenergize coil 40 and Parts which are the same energize coil 22 as described above. This would withdraw the piston from coil 23, deenergizing coil 39 and. energizing coil 40. Coil 22 would be deenergized and coil 2| would be energized, effecting the return stroke and completing the cycle.

We claim:

1. In a pump, a cylinder, two motor solenoids spaced longitudinally of the cylinder, a magnetic free piston reciprocable in the cylinder constituting an armature for and coupled with both solenoids, and means responsive to movement of the piston to either end of the cylinder for energizing the more remote solenoid more strong- 1y than the nearer solenoid to eiTect reciprocation of the piston, the last-named means comprising relay means coupled between each solenoid and a source of power, a saturable reactor transformer for energizing each relay means, a saturating winding on each transformer, a secondary coil on each transformer connected to energize the saturating winding of the other transformer, a control coil at each end of the cylinder coupled to the solenoids by the piston when it enters the respective end of the cylinder, and energizing connections from each coil to the saturating winding of the transformer controlling the relay means coupled to the nearer solenoid.

2. A system for the electrical control of movement of a member comprising, in combination. first and second motor solenoids, the said solenoids being adapted to be connected to a source of alternating current, an armature member adapted to be moved with respect to the solenoids, a control coil positioned adjacent each solenoid and remote from the remaining solenoid, the armature including magnetic material for increasing the coupling between the motor solenoid and the associated control coil when the armature is disposed adjacent the solenoid and one coil, a variable impedance element connected in series with each motor solenoid, the impedance element including a voltage responsive element for varying the impedance of the element, means connected between each control coil and the voltage responsive elements of the variable impedance elements for increasing the impedance of the element connected in series with the associated motor solenoid and for reducing the impedance of the remaining impedance element upon excitation of either control coil by increase of coupling with the associated motor solenoid caused by the armature.

3. A system for the electrical control of movement of a member comprising, in combination, first and second motor solenoids, the said solenoids being adapted to be connected to a source of alternating current, an armature member adapted to be moved with respect to the solenoids, a control coil positioned adjacent each solenoid and remote from the remaining solenoid, the armature including magnetic material for increasing the coupling between the motor sole noid and the associated control coil when the armature is disposed adjacent the solenoid and one coil, a variable impedance element connected in series with each motor solenoid, the impedance element including a voltage responsive element for varying the impedance of the element, transformer means associated with each motor solenoid including a primary winding adapted to be connected to a source of alternating current, a secondary winding connected to the voltage responsive element of an associated variable impedance element connected to the said motor solenoid and adapted to be connected to the source of alternating current, and third and fourth windings, and rectifying means connected between the third winding of each transformer and. the fourth winding of the remaining transformer and rectifying means connected between each control coil and the fourth winding of the associated transformer for de-energizing each motor solenoid and energizing the remaining solenoid upon excitation of a control coil.

4. The invention in accordance with claim 3, said variable impedance element comprising a gaseous conduction device having a control electrode as a voltage responsive control element.

5. The invention in accordance with claim 3, 15

said variable impedance element comprising a saturable reactor having a saturating winding as a voltage responsive control element.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 494,956 Johnson, et al Apr. 4, 1893 10 1,647,147 Roller Nov. 1, 1927 1,974,262 Cobe Sept. 18, 1934 2,177,795 Von Delden Oct. 31, 1939 2,182,014 Clark Dec. 5,- 1939 2,443,344

Ekleberry June 15, 1948

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