US2192629A - Control for fuel burning apparatus - Google Patents

Description

V. O. BEAM GONTROL FOR FUEL' BURNING APPARA'I'US March .5, 1940.

Filed June 20, '1936 2 Sheets-Sheet 1 INVENTOR.

ATTORNEYS ..4 ...i i-ICU March 5, 1940. v. o. BEAM CONTROL FOR FUEL BURNING APPARATUS 2 sheets-sheet 2 Filed June 20, 1936 ATTORNEYS.'

Patented Mar. 5, 1940 PATENT OFFICE CONTROL FOR, FUEL BURNING APPARATUS Vilynn 0. Beam, Cleveland Heights, Ohio, assignor to-The Bryant Heater Company, Cleveland, Ohio, a corporation of Ohio Application June 20,

6 Claims.

This invention relates to a new and improved thermal device and has particular reference to a thermal device for use in connection with the pilot burner of fluid fuel-consuming systems,

I such as gas-fired furnaces, boilers, and the like. The principal object of the invention is to provide a novel form and construction of thermal device which is speedy in action; which is selfcompensating as regards ambient temperature; which in its functioning, does not necessarily involve any flexure or bending of any member or l part thereof; and which is so constructed that itl may be used for directly or indirectly controlling the flow of fuel without requiring mechansm to multiply the movement generated or produced in the thermal device itself.

The invention may be briey summarized as consisting in certain novel combinations and arrangements of parts which will be described in the specification and set forth in the appended claims. A

In the accompanying sheets of drawings, Fig. 1 is a view -partly in elevation and partly in section showing the gas control -unit including the pilot burner, the thermal device, a pilot igniting coil, and a double-throw switch which is directly actuated by the thermal device, a portion of the main burner being shown adjacent the pilot burner, this view showing the parts of the thermal device in the position which they occupy when the pilot is extinguished and the device is cold, and the corresponding position of the parts of the double-throw switch;

Fig. 2 is a transverse sectional view on an enlarged scale substantially along the line -2-2 of Fig. 1; A

Fig. 3 is a vertical sectional view substantially along the line 3-3 of Fig. 2; I

Fig. 4 is a vertical sectional view substantially along the line 4 4 of Fig. 3;

- Fig. 5 is a view showing a portion of the equipment illustrated in Fig. 1 but with the thermal device. and the double-throw switch operated thereby in substantially the position which these 45 parts. occupy when thethermal device is heated.

Referring now to the drawings, I0 represents the main burner to which gas will be supplied' from the usual supply pipe. I wish it to be understood however that the presentv invention,` although useful in connection -with gas-fired boilers, furnaces, heaters, and the like, is not necessarily confined thereto. In igniting relation to the main burner is a pilot II which, as well as the thermal device to be referred to presently, forms a part of a unit having 4a 1936, Serial No. 86,381

y tubular casing I2 which may be rectangularly or otherwise shaped in cross-section, this casing having a horizontal main portion and at its inner end an upright or vertical portion I2a. Gas is supplied to the pilot II by a pipe I3 extending 5 through the horizontal portion of the casing, the pipe I3 being connected to the pilot II in a manner such that there will be supplied to the latter a suitable mixture of air and gas. The pilot II extends up from the horizontal portion of the casing I2 in front of the upright portion I2a.l thereof and is steadied by the ange of a bracket I 4 secured to the upper part 'of the vertical portion I2a of the casing. If a main valve of the diaphragm type is utilized, a bleed pipe is employed to carry the gas from the upper chamber of the valve when the latter is to be opened by gas pressure beneath the diaphragm, and-in that case the bleed pipe here indicated at I5 may also extend through the casing I2 alongside the 20 pilot pipe -I3 and it may have a vertical extension alongside the pilot II but will terminate short of the upper end thereof, as indicated in Fig. 4. However, this bleed pipe forms no part of the present invention and will not be further referred to.

Considering next the thermal device constituting the principal feature of the present invention, it will be observed that this device I6 is composed of two members I6a and I6b which 30 are, pivotally connected by cross-pins I6c to the upper part of the vertical portion I2a of the casing I2 and project outwardly and upwardly therefrom. At their upper ends these members are pivotally connected together by a pivot pin I6d. The member Ilia is next to the pilot II and this member which when compared with the member IIib is relatively short, may be termed the hot member of the thermal device. The other member I 6b of the vthermal device is rela- 40 tively remote from and shielded from the pilot flame by the hot member Ilia and may be termed the cold member of the device. This latter member is relatively long and is in the form of a lever which extends down beyond its pivot pin I 6c 45 and at its lower end is connected to the gas controlling element which it is to operate. From their pivot pins |6c to the upper common pivot pin IBd the two members Ilia and I6b are normally of equal length, the axes of the three pivot pins forming the corners of an acute isosceles triangle when the element is cold; Though the major portion ofthe member I6a and the major portion of the upper part of the member I Sb are `parallel or ,substantially parallel,` their upper 55 ends are in this instance curved inwardly and placed in overlapping relation so that they can be conveniently connected together by the pivot pin I6d. As will appear presently, the heat differential between the member IBa and the upper portion of the member I6b causes the member Ilia to expand linearly and the two fixed pivot points I6c together with the fact that the members are pivotally coupled together at their ends compel the relatively hot member to rock on its pivot I6c (to the right as the same is viewed in Fig. l), thus imparting a similar rocking movement to the member I6b which thus acts as a lever to transmit' at its lower end to the part to be actuated a movement the extent of which can be made anything desired within reasonable limits by the appropriate selection of the ratio of the lengths of the two lever arms above and 'below the pivot I6c.

In Fig. 5 I have illustrated the manner in which the thermal element functions by showing in full lines the position of the parts of the thermal element when the same is heated and by dotted lines their positions when the element is cold. In this same figure I have shown how the movement of the lower end of the member` I6b of the element shifts the middle contact I8d of the switch I8 from the position shown in Fig. 1 to the position wherein the middle contact engages the upper contact I 8e.

Reverting to the thermal device I6, it is to be observed that neither the hot member IBa nor the cold member I6b thereof is designed to be flexed by the action of the pilot flame, in fact they are especially shaped to avoid flexure and to that end they are made quite stiff and rigid by being made channel-shaped; as will best be seen by reference to Fig. 2, but the channel-shape, in addition to its strength-imparting function, aids ln the quick cooling and heating of the members andparticularly the hot member Ilia. Additionally, the channel of the hot member I6a faces the pilot flame or that part thereof which heats it and serves as a trough to receive and guide the flame and prevents its impinging upon the cold member IIib. The hot and cold members I6a and |611` of the device may be formed of precisely the same metal or alloy so as to have the same thermal expansion, and while they have generally the same or substantially the same expansion coefiicient, so that the element will be unaffected by ambient temperatures, under some circumstances one of the members, preferably the hot member, may have a somewhat higher thermal expansion than the other, depending upon the surrounding temperature in which the element is designed to work. 'I'hey are formed of a material or materials having good load carrying characteristics so as to resist without bending or distortion the stresses set up during the functioning of the element and will have high thermal expansion. Nickel-chrome steel has been found quite satisfactory, and if one member is to have a somewhat different thermal expansion than the other, this can be accomplished by varying the proportions of the ingredients of the alloy.

By reference to Figs. 1, 2, 3 and 4, it will be seen that the pilot has a lower orifice I Ia for the emission of gas to produce the flame F (shown by dotted lines in Fig. 1) which heats the adjacent member Ilia of the thermal element and an upper orifice IIb for the emission of gas for the flame F', also shown by dotted lines in Fig. 1, for t igniting the .main burner or burners, these two orices being connected by a spiral slot I Ic so that when the gas is ignited at the lower orifice Ila it will travel up the slot and ignite the gas at the upper orifice IIb.

It is desirable that the pilot be lit by a suitable' igniter generally-electrically actuated, and while different forms vof igniters may be employed, I prefer to use an igniter-of the hot wire type generally in the form of a coil which on the passage of current therethrough becomes incandescent and therefore sufficiently hot to ignite the gas surrounding it.

On top of the vertical portion I2aof the casing l2 at the side of the two members of the thermal device I mount a block I9 of heat-resisting material havinga channel I9a extending horizontally therethrough, this channel being located alongside and facing the members of the thermal element and projecting-inwardly beyond the same toward the pilot II, the inner end of the channel being located adjacent the lower orifice Ila of the pilot I I. In this channel is placed the igniter coil 20 held in place by terminal screws 20a to v which current supplying conductors may be -connected.

This device functions as follows: The parts are so related that the gas emerging from the lower orifice Ila of the pilot envelops the coil 2U, and when current is passed through the coil and the latter becomes incandescent, it ignites this gas and therefore starts ames at the pilot orifices,

but as soon as the flame F is established it is caused by convection to curl upwardly into the channel of the hot member ISa of the thermal' fuel consuming apparatus, the gas to the pilot is turned on and the coil 20 is caused to be energized, after which the pilot will be ignited. As soon as this occurs the ame F rises and instantly after the ignition occurs the flame is out of contact with the igniter coil.

The flame now plays on the hot member Ilia of the thermal device, and while the cold member Ib remains relatively cool, the hot member expands and lengthens, changing the distance between its pivotIBc andthe upper pivot I6d which pivotally connects the upper ends of the thermal members. As the hot member I6a gradually lengthens, it transmits lateral thrust to the upper end of the cold member'lb, causingthe pivot pin IBd to move in a clockwise direction as the shame is viewed. in Fig. 1 to a position about as shown in full lines in Fig. 5 so that both members rock in a clockwise direction about their respective pivots ISC and move the switch actuating rod I1 to the left. The movement imparted directly by the long arm or member of the thermal device to the switch member I8b is sufiicient to move the middle contact Id from the position shown in Fig. 1, i. e., in engagement with the lower contact Isc, into engagement with the upper contact I8e, as shown in Fig. 5. It might be stated at this point that the time element of this part of the cycle can be varied'by adjusting the positions of the two contacts I8e and I8c with reference to the middle contact I8d. This can be done by means of an adjusting screw 18h which extends through the top of the switch box |8a and engages the'upper contact I8e. This contact is connected with the lower contact l8c extinguished and the thermal members are cool or reach equal temperature, the parts are restored to their former positions shown in Fig. 1

the spring Ila assisting this action.

When the thermal element is actuated by the pilot ame in the manner just explained so as to bring the middlecontact Id into engagement with the upper vcontact I8e of the switch I8,

a circuit may be completed through electric apparatus (not shown) for turning on the gas to main burner I0. At the same time the circuit for ig-` niter coil 20, which includes the middle contact Id and the lower contactv 8c of switch I8 is broken.

Various -parts of the apparatus disclosed but not claimed herein are claimed in two applications l led as divisions of this application, namely, ap-

plication Serial No. 145,087, led May 27, 1937,

for Burner control system, and application Serial No. 145,088, led May 27, 1937, for Fuel burning equipment.

While I have shown somewhat in detail the preferred embodiment of the present invention, I do not desire to b confined to the details or specic members described above as the principle of the invention maybe otherwise utilized, and I therefore aim in my claims to cover Aall modiiications which do not involve a departure from the spirit and scope of the invention in its broadest aspects. Having thus described my invention, I claim:

l. In a pilot ame responsive device, a pair:

of elongated members arranged alongside each other having separate pivotal mounting connections at closely adjacent locations and connected together remotely from said connections, one of said members having a longitudinal groove adapted to receive and guide a pilotl flame and extend it along a substantial length of said member and thereby take maximum heat from the flame.

2. In a pilot ame responsive device, a pair of elongated members arranged alongside each other having separate pivotal mounting connections at closely adjacent locations and connected together remotely from said connections, one of said members having a longitudinal groove facing from the other member adapted to receive and'guide a pilot flame and extend it along 'a substantial length of said member'and thereby take maximum heat from the ame substantially to the exclusion of the other member.

3. In a thermally responsive device for use in connection with the pilot burner of a fuel burningsystem, a support, a pair of pivots on said support spaced apart horizontally a slight distance, two upright elongated members each mounted on one of said pivots, said members being connected together at a point remote from said pivots, one of said members having a longitudinal groove therein on its side remote from the other member, whereby the pilot flame may be caused-to enter said groove .and travel upwardly therealong for the heating of the'grooved member independently of the other member.

4. In a thermally responsive device' for use in connection with the pilot burner of a fuel burning system, a support, a pair v ofe pivots on s'aid support spaced apart slightly, two elongated members each mounted on one of said pivots, said members being connected together at a point remote from said pivots, one of said members having an extension beyond its pivot point on the side thereof remote .from the point of connection between the members, to which extension a control connection may be attached, and means for subjecting one of said members between its pivot and its connection with the other member to the action of the pilot flame independently of the other member.

, 5. In a thermally responsive device for use in connection with the pilot burner of a fuel burning system, a support, a pair of pivots on said support spaced apart slightly, and two elongated channel members arranged back to back each mounted upon one of said pivots, saidl members being connected together at a point remote from said pivots, whereby the pilot iiame may be projected into the channel of one of said members yond the end of the tube, an elongated-cold member mounted intermediate its endson the other of said pivots and connected with the projecting end of the hot member, a portion of one of said members extending toward the other end of the tubular support interiorly of the same, and means associatedwith the Atubular support adjacent the free extremity of said extending portion -adapted to be actuated by the latter upon the heating ofl the hot member independently of the cold member.

VILYNN O.

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