US2638121A

US2638121A - Control device

Info

Publication number: US2638121A
Authority: US
Inventors: Earnest J Dillman
Original assignee: Detroit Controls Corp
Current assignee: Detroit Controls Corp
Priority date: 1948-05-11
Filing date: 1948-05-11
Publication date: 1953-05-12
Anticipated expiration: 1970-05-12

Description

y 1953 E. J. DILLMAN 2,638,121

CONTROL DEVICE Filed May 11, 1948 4 Sheets-Sheet l MKM 4L1 ATTORNEY May 12, 1953 E. J. DILLMAN 2,638,121

CONTROL DEVICE Filed May 11, 1948 4 Sheets-Sheet 5 IN VEN TOR.

Mi M

I 2 W (M FIG 5 AL ATTORNEY y 53 E. J. DILLMAN 2,638,121

CONTROL DEVICE Filed y 11, 8 4 Sheets-Sheet 4 IN V EN TOR.

Mg. bimam,

M ATTORNEY Patented May 12, 1953 CONTROL DEVICE Earnest J., Dillrnan, Detroit, Mich, assignor to Detroit Controls Corporation, a corporation of Michigan Application May 11, 1948, Serial No. 26,429

8 Claims.

This invention relates to new and useful immovements in liquid fuel burner systems and m re p rticularly to control devices therefor,

One of the objects of this invention is to provide a control system having a plurality of liquid .fuel burners having a. common supply of fuel.

An th r o j t is to provide a control d v ce for selectively directing the new of iquid f el o each of a plurality of l qu d fuel burners.

Another object is to provide a. liquid flow controlling device having a pressure determining means therein and h ving a means f r lead ng fuel back to the source of supply at p es ur s below that determined by the pressure determining means.

Another object is to provide a control device having a means for selectively directing the flow of fuel to two burners and for transferring control between two control systems which control the operation 01' said burners.

Another object is to provide a novel valve and switch combination in a liquid fuel burner control device,

Another object is to provide a control device for a two burner control system by which the fuel 'supply is discontinued to one burner before the control valve switches the supply from that burner to the other.

Another object is to provide a novel means of adjustment for an operating lever in a control device.

Another object is to provide a control device having a novel means for inducing a snap or quick action of an operating member.

Other objects will become apparent from time to time throughout the specification and claims as hereinafter related.

This invention consists of the new and im.. proved control system and control device therefor and of the combination and cooperation of the partsthereof which will be described more fully hereinafter and the novelty of which will be particularly pointed ,out and distinctly claimed.

In the accompanying drawings to be taken as part of the specification, there is clearly and fully illustrated one preferred embodiment of this invention in which drawings:

Figure 1 is a view in front elevation of a con trol device embodying this invention,

Fig. 2 is a op Plan view of this control device,

Fig. 8 is a sectional view taken on the section line 3-.--3 of Fig, 2 of this control device and which shows the construction and relation of the control valves to the various outlet passageways,

Fig, 4 is a sectional view taken on the section line "4 of Fig. 2, and which shows the thermostatic means for operating this device.

Fi 5 is a sectional view taken on the line 5-5 of Fig. 4 and which shows the liquid inlet to the control device and the actuating lever therefor,

Fi 6. is a sectional vi w ak o the se t n li e 6* f g! ig. 7 is a plan view of this control device with the cover member removed an shown n Partia section to show the means for adjusting the Sn il acting device,

Fig. 8 is a bottom plan view of the cover member of this device when removed, and

Fig, 9 is a diagrammatic view of this control device installed in a control system for controlling a pair of liquid fuel burners.

Referring to the drawings by characters of reference, there is a control device I comprising a liquid fuel receiving casing 2 having an inlet passageway 3 and a p ir f outlet passag s. 5- he cas ng 2 has a cover m er 6 of aneleetric insulating material which is secured to and seals the open top of the casin the cover membe 5 being secured to the casing 2 On. a f ange 1 Whiflh extends around t e o en top f the casing- "Ihe e is a va e e n memb 8 h ch is secured t the c er mem r .6 alone one nd n9 ion th r f. Th va ve casin 8 has a pai o pr e porti s 9, 10 w h e d, through a pa r f ap rtu s n the c er em er 5. The projecting portions 9, 1.0 are externally screwthreaded and are secured to the cover member 8 by a, pair of nuts I I, I2. The projecting portions 9, ill have bores I3, [4 therein which open into smaller bores I5, l6 forming valve ports and cooperating with the bores 13, I4 to form valve seats. There are a pair of valve members ll, [8 which fit slidably in the bores l3, l4 and which function to control how of liquid fuel therethrough. The valve members ll, 18 are of polygonal cross-section to permit flow of fuel to the valve ports l5, It. The valve casing 8 has a pair of cylindrical cavities at each end thereof in which are screw-threadedly secured a pair of

plug members

19, 20. The bores or ducts l5, 16 open respectively into passages 2! 22 which communicate at one end thereof through bleed orifices 23, 24 into a bleed or auxiliary outlet passageway 25. The other ends of the passages 2t, 22 communicate with annular cavities 26, 2'! respectively which are closed by resilient elastic diaphragms 28, 29 respectively of a pair of diaphragm type check valves. The plug members It, 20 in the valve casing 8 are each hollow and have hollow operating pistons 30, 3t therein which are held compressively against the diaphragms 28, 29 by

helical springs

32, 33. lhe diaphragms 28, 29 which are clamped in position by the

plug memhere

19, 2 respectively, are held compressively closing a pair of passages 34, 35 which open into the outlet passages 4, 5. Secured to the under surface of the cover member 6 is a bracket 36 which supports the fulcrum pin 31 of an operating lever 38 which controls the opening and closing movement of the valves ll, 18, The operating lever 38 fits at its opposite ends into lostmotion slots 39, 40 in the valves |'i, I8. The operating lever 38 is adjustably secured to a lever supporting member 4| which is formed of sheet metal having a plane central portion and downturned projections or ears 42 at each end through which extends the pivot pin 37. There is a supporting member 43 of an electric insulating material which is secured to and carried by the lever supporting member 4|. The operating lever 33 has a grooved central portion which rides on the pivot pin and has a pair of apertures on opposite sides of the fulcrum pin 31 through which extend a pair of bolts 44, 45 which are adjustably secured in the supporting members 4|, 43. There is a helical spring 46 surrounding each of the bolts 44, 45 which is positioned between the lever supporting member 4| and the lever 33 and hich holds the lever 38 compressively against the heads of the bolts 44, 45. It is obvious then that the lever 38 can be rotatably adjusted relative to the supporting member 4| by proper inward and outward adjustment of the bolts 44, 45 thereby permitting adjustment of the amount of opening of the control valves I1, I 8.

The cover member 5 of the casing 2 carries four pairs of electrical contact terminals or binding posts 41 which are connected to fixed contacts 48 of an electr c switch. There are four pairs of movable switch contacts 49 which are carried by the supporting member 43 on the lever supporting member 4| and which are connected thereto by resilient arms 50. It is seen then that upon rocking movement of the lever in one direction one of the valves is opened and one closed and two pairs of movable contacts are closed against their respective fixed contacts while two pairs of movable contacts are opened. The lever supporting member 4| has a downturned and bifurcated projectin portion 5| at the end opposite the valves. There is a lever 52 which is pivoted on a bracket 53 and which extends between the prongs of the bifurcated projection 5|. The lever 52 when moved engages one or the other of the prongs of the bifurcated projection 5| and causes the lever and electric contacts to be rocked. Positioned between flames on the lever 52 there is a pivoted member 54 which has a pair of annular shoulders out into the op osite faces thereof. The casing 2 has a pair of apertures 55, 55 which are oppositely alined in line with the pivoted annular member 54. There is a plug member 5'! which is screw-threadedly secured in the aperture 55 and which has an adjustment screw 53 extending lon itudinally there through into the chamber enclosed by the easing 2. The adjustment screw 58 is enclosed by a cover member 59 which is screw-threadedly secured to the exterior of the plug member 51.

The adjustment screw 58 has a small project ng portion 6|! which pro ects into a cylindrical cavity in a spring supporting member 6|. The supporting member 6| has an annular flan e 82 thereon against hich bears one end of a helical spring 53, the other end of which bears a ainst one annular shoulder of the pivoted member 54. At the opposite side of the casin 2 t ere is a plug member 64 which is screw-threade lly secured in the aperture 55. The lu member 64 has a bore 65 extendin substantially along the lon itudinal axis thereof, w ich bore is of reduced size in t e inner end portion thereof. There is a piston member 6 w ich sli ably fi s the reduced end portion of the bore 65 and which extends into the chamber enclosed by the casing 2 and which has an annular shoulder upon which seats a spring supporting member 5? having a flange 58. There is a helical spring 69 which is compressively positioned between the flange portion 58 of the member 57 and the other annular shoulder of the pivoted member 54, the

springs

69, 53 being oppositely alined. Positioned in the enlarged portion of the bore 55 and extending partially into the reduced portion is an elastic plug member of a resiliently elastic material such as a rubber or synthetic rubber. The bore 65 at its enlarged end opens into a cylindrical recess or cavity H which is closed by a cover member I2. The enlarged open end of the bore 65 is closed off from the cavity H by a flexible diaphragm l3 of a resiliently elastic material such as rubber or synthetic rubber, The diaphragm I3- is secured against vthe end wall of the recess H by the cover member 12 and abuts the plug member 10, the cover member |2 being held rigidly in position by an inturned annular flange M. The cover member 72 has .an aperture therein opening into the cavity H and in which is sealed a tube or conduit 15 which leads to a thermostatic element 15. The bulb element 16 contains an expansible fluid vwhich is responsive to temperature and operable to transmit an expansive force to the cavity (I which is expanded thereby and its force transmitted through the diaphragm i3 and plug 70 to move the piston 65. The aforementioned movement of the piston 55 is transmitted through the spring 69 to the lever 52 for operating the control lever 38. The lever 52 has a projecting portion 11 at its free end portion which extends into a cylindrical recess iii in the bottom wall of the casing 2, the walls of the cylindrical recess !8 functionins as limit stops for the lever 52. There is another lever 75 which is pivoted on a bracket on the side wall of the casing 2 and which has an adjustment screw or bolt 8| at its free end port on. There is a threaded member 82 screwthreadedly secured on the bolt 8| and to which is secured one end of a helical spring 83. The other end of the spring 83 is secured to a screw threaded member 84 on an adjustment bolt 85 which extends through an aperture 86 in the end wall of the casing 2, the aperture 86 having an enlarged outer end portion which is closed by a bolt-like closure member 81. The lever 52 has an inturned flange portion 88 on its free'end against which is pivoted one end of a pivoted mem er 89, the other end of which is pivoted against the midortion of the lever 19. The pivoted member 89 is compressively held by'the force of the spring 83 between the lever 19 and the flan e portion 88 of the lever 52 and is operable to transmit a biasing thrust therebetween. In operation this control device functions as follows:

Liquid fuel is supplied to the chamber enclosed by the casing 2 through the inlet 3 under press re by a pump 90 (shown diagrammatically in Fi 9). This fuel is discharged through the open val e M under pressure and through the passages Ni, 2.2 to the annular cavity 21 which is closed by the diaphragm check valve 29. The check valve 29 is set to open at a predetermined pressure of say 60 p. s. i. at which pressure the dia hra m 29 forces the piston 23 into the cylindrical cavity in the plug member 24 against the sprint, .As the diaphragm 29 is moved, the o ening to the passage 35 is opened to permit flow t rough that passage into the outlet passage 5, which leads to one of the burners controlled by this device. When the heat output in the one burner has reached a sufiicient amount the thermostatic bulb 16 which is responsiveto said heat output will transmit fluid expansion to the chamber H and an expansive force through the diaphragm and plug member as heretofore described to the piston 66 which acts through the sprin 69 to move the lever 52 against the force of the spring 63, The amount of force required to move the lever 52 may be adjusted by the adjustment screw 58 which determines the compressive force exerted by the spring 63 which adjustment will determined the temperature of the bulb element 16 which is required to cause the lever 52 to be moved. As the lever 52 is moved, the pivoted member 89 pivots therewith and causes the lever 19 to move outward thus tensioning the spring 83. When the lever 52 has moved to an over-center position the spring 83 acting through the lever!!! and the pivoted member 89 will cause the lever 52 to move through the remainder of its travel with a snap action. The movement of the lever 52 with a snap action will cause it to engage one of the prongs of the bifurcated projection 5| and to rock the lever 38 and electrical. contact arms with a snap action. There is a fraction spring 9| which is positioned between the end portion 51 of the lever supporting structure ll and the supporting bracket 35 which functions to hold the lever supporting member 4] in any predetermined position when cracking force is not being applied thereto. This spring bears against two raised or embossed portions of the projecting port on 5] and will hold the lever supporting member 4! at one of the two extremes of movement with the valve tacts. The lever 38 which operates the valves H, 18 extends into the slotted end portions .35, ll of these'valves and is operable to provide a lost motion in the opening of these valves. When the lever begins its movement it must move from one side of'one of the slots 39 or 4D to the other side of the slot before the valve can begin to open. The-oil pressure at which the burner is operated is normally about 90 p. s. i. and: this pressure is sufiicient to resist opening of the valve which is closed until the operating pressure drops to a small value of say, p. s. i. The lost motion feature in the valves and the pressure 'which holds the valve I! closed is operable-to .hold the valve closed while permitting the switch ,contacts to open. With the switch contacts open the pump is deenergized and when the pressure in the valve casing drops to the lower pressure (10 p. s. i.) the valves and switch contacts are permitted to move through the remainder of their travel to re-establish the pump and burner circuit and to open and close the respective valves as required. The switch contacts which are fopened and closed in sequential synchronization with the opening and closing of the valves are operable to switch between two sets of control circuits which control the operation of the pump 90 which'supplies fuel to the open one of the valves. The central outlet passageway 25 or bleed passageway communicates through reduced -o pen'mg or orifices 13, 24 with the passages 2|,

22 leading from the outlet l5, Hi from thevalvo I1, 18. During periods when only one of the burners supplied by this control device is in operation the switching of the valve and switch contacts will deenergize the pump but the inertia of the pump will cause a fuel pressure to continue for a short time and fuel could be supplied through the open valve to the inactive burner. With the bleed outlet and lost motion valve opening described, this shore supply of fuel through the inactive burner valve portwould be so reduced in pressure as to be insufficient to open the check valve and would bebled through the orifices and discharged through the bleed outlet 25 and a connecting conduit back to-the source of fuel supply..

In Fig. 9 the control device heretofore described is shown installed in a control system for controlling flow of fuel to a household heating burner and a domestic water heating burner. In this system there is a fuel sump 92 for supplying fuel to a conduit 93 leading to the pump 90, the pump supplying fuel through the conduit 94 to the inlet 3 of the control device. From the control device 1 one conduit 95 leads to a house heating burner 96 and another conduit 91 leads to a domestic water heating burner 98. The

burners

95, 93 are supplied with air by a common motor driven fan 83 by which motor the pump 96 is driven. There is an air duct I00 leading from the fan 58 to the burner 96 and a branch duct I 0! leading to the burner 98. The stack I82 from the burner 98 is connected to the stack H33 of the house heating burner 96. The thermostatic bulb element 15 is responsive to'the temperature of the water supply and is inserted in the water heating jacket 04 surrounding the burner 88. The electric control systemfor the control of the

burners

96, 98 is as follows:

There is a main power source I05 from-which a pair of conductors IE5, I07 run to 'the'terminals I08, I09 of an electric primary control device H0. From the terminal III on the control device no a conductor H2runs to the terminal N3 of the motor of the fan 99 which is'connected to the main power source H35 by a'c'onductor H4 leading from the other fan motorterniinal H5. The terminals H38, I 69 of the control device H8 are connected to the primary H6 of a transformer i H. The transformer i I! has a secondary coil 1 l B which has three terminal connections thereon. From one of the secondary terminals H9 a conductor i20 runs to a thermostatio-warp switch Hi, the contacts |22,'l-23 of which are normally closed. From the fixed contact l23 of the warp switch I21 a conductor I24 leads to a terminal of the control device Hi3. From the terminal I26 of the transformer secondary i 18 a conductor runs to a heater coil I21 for the thermal warp switch 12!, the heater coil i2! being connected by a conductor I28 to a terminal 12!! on the control device! Hl. From the terminal of the transformer secondary I18 a conductor l3! leads to a movable contact 32 of a bicole relay switch [33. The fixed contact 134 of the relay switch 133 is connected to the relay coil which is in turn connected by condoctor 13%; to the terminal I31 of the control olevice H8. The fixed relay contact 134 is also connected by a conductor I38 to a terminal 1390f the control device Hit and by conductors H0, 14! and the closed. contacts 142, .143 of a thermostatic stack switch I44 to the control device terminal 145. There is a iumper H5 which'leads from the transformer primary H6 to a second movable contact I41 cooperable with a fixed cons tact I48 of the relay switch I33. The fixed contact I46 0f the relay switch I33 is connected by a conductor I49 to the terminal III. On the control device -I there are a plurality of pairs of fixed switch contacts I53 and I5I, I52 and I53, I54 and I55, I56 and I51 with which cooperate the movable pairs of contacts 49. There is a conductor I58 running from the terminal I25 of the control device III) to the fixed contact I52 of the control device I. The terminal I31 of the control device H is connected by a conductor I59 to the contact I53, which contact is connected by a conductor I60 to the terminal I6I of a room thermostat I62. The thermostat terminal I6I is connected to a bimetal element I63 which carries a movable contact I64 and is also connected to a compensating heater coil I65 which is in turn connected by a conductor I66 to the contact I55 of the control device I. The fixed contact I61 which cooperates with the movable contact I64 is connected by a conductor I68 to the contact I51 of the control device I. There is a jumper wire I69 connecting the contacts I52 and I56 of the control device I and a similar jumper I19 connecting the contacts II, I55. From the contact -I5I a conductor I1I leads to the terminal I29 of the control device H0 and a conductor I12 similarly connects the contact I 54 to the terminal I45. From the terminal I50 a conductor I13 leads to the fixed contact I14 of a thermostatic stack switch I15, the other contact of which (I16) is normally closed thereagainst. From the movable contact I16 of the thermostatic stack switch I a conductor I11 leads to the terminal I 39 of the control device I III.

In operation this control system functions as follows:

The control device I is shown diagrammatically and corresponds to the position shown in the various views of the device itself. In the position shown, the hot water tank I64 has cooled and the movable pairs of contacts 49 have closed against the fixed pairs of contacts I50 and I5I, I52 and I53 to complete a control circuit for supplying fuel to the hot water heater. In this position (see Fig. 3) the valve I8 of the control device is open and operable to permit passage of fuel to the hot water heater 98 through conduit 91-. A circuit is completed from the main power source I05 to conductors I06, I61 to the primary H6 of the transformer II1. With the transformer II1 energized a circuit is completed from the transformersecondary terminal H9 by way of conductor I20, closed contacts I22, I23 of the warp switch I2I and conductor I24 to the control device terminal I25. From the terminal I25 the circuit runs through conductor I53 to the contact I 52 of the control device I, through the closed switch contacts to the contact I53 and thence by conductor I59 to the terminal I31 of the control device -I I 0. From the terminal I31 the circuit runs by conductor I3 6 to the coil I35 of the relay I33 and thence by conductor I 38 to the terminal I 39. From the terminal I39 the circuit runs by conductor I11 through the closed contacts I14, I16

of the stack switch I15 and by conductor I13 to contact I of the control device I. From contact I50 the circuit is completed through the closed contacts 49 to contact I5I and thence by conductor I1I to terminal I29 of the control device IIO. From the terminal I29 the circuit is completed by conductor I28 and the heater coil I21 to the terminal I26 on the transformer sec-- 'ondary I I8. It is thus seen that a circuit is com- 8 pleted through the coilof the relay switch I33 to the closed contacts of the timer warp switch I2 5 and through the closed contacts of the stack switch I15. When the relay switch I33 is energized the. movable contacts I32, I41 are closed against the fixed contacts I 34, I48. When the contacts I41, I48 are closed the circuit is completed from the main power source by conductor I06 and conductor I46, the closed contacts I41, I48 and conductor M9 to the terminal III of the control device III]. From the control terminal I I I the circuit runs by conductor I I2 to the motor of the fan 99 and by conductor H4 back to the main power source. It is then seen that upon energization of the relay switch I33 the circuit is completed through the fan motor for operation of the fan- 99 and for operation of the pump which supplies fuel through the open valve I8 and outlet 5 in the control device I to the hot water burner 96 through the conduit 91. Simultaneous with the establishment of the circuit for energization of the fan and pump a circuit is completed through the closed contacts I32, I34 of the relay switch from the terminal I30 of the transformer secondary H8. This circuit is a holding circuit which runs from the terminal I I8 by conductori3i, closed contacts I32, I34, the relay coil I35, conductor I36 to the terminal I31 of the control device III). From the terminal I31 the circuit runs by conductor I59, contacts I52, I53, conductor I59, terminal I25, conductor I24, the closed contacts I23, I22 of the warp switch I2I and conductor I20 back to the terminal II9 of the transformer secondary II6. Since the initial energizing circuit for the relay switch I33 was established through the heater I21 for the warp switch I2I and the stack switch I15, it will be obvious that unless the initial circuit is opened Within a short predetermined time the heater I21 will cause the contacts I22, I23 of the warp switch I2I to open thus deenergizing the relay I33 and stopping the fan and pump. The stack switch I15 has a thermostatic element positioned in the stack from the hot water burner and upon occurrence of flame in the hot water burner the therswitch I15 thus breaking the circuit through the heater coil I21 of the warp switch I2I and deenergizing the initial circuit for energizing the relay I33. The burner 98 will then continue to heat until the domestic hot water supply is heated to the desired temperature at which time the thermostatic power element bulb 1 6 will have been heated sufficiently to transmit power to. the control device I and cause the levers to move thus closing the valve I8 and opening the valve I1 and opening and closing the corresponding switch contacts. As was described heretofore the lost motion in the opening of the valve I1 is such that the circuit through the switch contacts across the terminals I59 and I5I, I52 and I53 in the control device I are broken and the pump 90 ole-energized prior to the opening of the valve I1 so that fuel will not be ejected through the valve I1 should the household burner 96 not require heat. With the valve I1 open and the switch contacts I54 and I55, I 56 and I51 closed which occurs sequentially to the opening of contacts I50 and I5I, I52 and I53 the control device I is now in position to supply fuel to the household burner 96 as required. As described before, the transformer II1 of the control device H0 is en ergized at all times from the main power source I95. With the switch contacts moved-as described in the control device i a new circuit will now be completed from the terminal H9 of the transformer secondary IIB through the contacts I22, I23 of the warp switch I2i and by terminal I25 and conductor I58 to the contact I52 of the control device I. From the contact I52 the circuit runs by the jumper 569 to and through the closed contacts 56, I51 and by conductor I68 to the fixed contact Isl of the room thermostat H52. If the room thermostat I52 is demanding heat and the contact IE4 is closed against the contact It? the circuit will be completed through the bimetal I53 I60 to contact I53 of the control device 1. From the contact 553 conductors I59, 136 run to the coil I35 of the relay switch I33. From the relay coil I53 a circuit runs by conductor I49 to the closed contacts I42, 143 of the household burner stack switch I 35 and by conductors I4I, I12 to the contact I54 of the control device I. From thevcontact I55 the circuit runs through contact I55, the conductor N55 to the compensating heater 355 on the room thermostat H52. A branch cir-v cult runs from a contact I55 by jumper to contact i5l which is connected by conductor ill to a. terminal 29 on the control device I I0. The circuit is then completed from. the terminal IZQ by conductor I28 and the warp switch heater l2! to the terminal I26 on the transformer secondary IIS. From this circuit it is seen that the circuit is completed through the room thermostat H52 as heat is called for and through the closed contacts of the stack switch I at, the relay coil I35, and through the contacts of the warp switch heater I21. When the relay switch I33 is energized and the contacts I41 and I48 closed, the circuit is completed as previously described through the fan motor for energizing the fan 99 and the pump 90 for supplying of fuel to the household burner through the open valve I! and outlet 4 by conduit 95. Upon closing of the contacts I32, 13s of the relay switch I33, a circuit is established from the transformer secondary terminal i150 through the closed. contacts F32, I 34, the relay coil 35,.

conductors

136, 59, ISO to the room thermostat 152. From. the room thermostat i 32 the circuit runs by conductor i i-8, contacts I56, 151, jumper Ills, conductors I58, ill, the closed contacts I22, 123 of the warp switch. I21 and conductor I20 leading back to the transformer secondary terminal I19. As was described before, the initial circuit for the energizetion oi the relay coil 135 runs through the closed contacts of both the stack switch 544-: and the warp switch 12!, and the warp switch heater I21;

Since the holding. circuit for the relay coil 35 through the closed contacts L32, [34 also runs through the closed contacts of the warp switch l2I it is necessary that the initial relay cofl energizing circuit be broken within a short predetermined time or the opening of the warp switch'contacts I22, $23 will tie-energize both the initial and. the holding, circuits of the relay I33 and will stop the fan and pump. As was described for the control system of the water heater, the staclr switch I'M performs a similar function to the stack switch I in that it is responsiveto the occurrence of flame in. the household burner Upon occurrence of flame in the household burner 96 the stack switch contacts [42, M3 will open thus tie-energizing the circuit through the warp switch heater I21 and leaving the holding circuit to the relay coil I35 in control of theoperation of the fan and pump. As was described heretofore the holding circuit and terminal IGI, by conductor for the relay coil I includes the switch contacts of the control device I and the contacts I64, I67 of the thermostat I62 so that if the room thermostat should be satisfied the relay coil will be ale-energized or if the househould water supply should cool a sufiicient amount that the switches of the control device I are moved the household heating circuit would similarly be broken. It should be noted that the check valves cs, 29' and the bleed outlet 25 as described heretoforepermit the bleeding of fuel back to the sump d2 by a conduit 93 This bleed arrangement together with the delayed opening of the valve as pre viously described prevents fuel from being discharged into the household burner 96 when the control device 6 switches over from the water heating burner if the room thermostat Hi2 is not calling for heat and causes fuel pressure created by the inertia of the pump to be relieved through the bleed outlet 25 back to the sump 92 From the description heretofore given it is seen that there is provided a pair of circuit networks for controlling a two burner system whfleby the demand of heat by the domestic water heating system will switch the control device I to a posi-' tion for supplying fuel to the water heating burner 98 and switch to a control system for the burner 98. Similarly, when the water supply is adequately heated the control devieewill switch fuel back to the house heating burner 95 and place its control system in control.

Having thus described the invention, what is claimed and is desired to be secured by Letters Patent of the United States is:

l. A control device comprising a casing having a fluid. inlet and a pair of fluid outlets, a pair of valves for controlling ii'uid flow through said outlets, means for opening and closing said valves,- ineans positioned in each of said outlets and operable to determine the pressure of fluid discharging therethrough, an auxiliary outlet from said casing, and means for bleeding fluid from said first-named outlets to saidauxiliary outlet at points between said valves and said pressure determining means.

2. A control device comprising a casing having a fluid inlet and a pair of. fluid outlets, a pair of valves for controlling fluid now through said outlets, means for opening and closing said valves, means positioned in each'of said outlets and operable to determine the pressure of fluid discharging therethrough, an auxiliary outlet' from said casing, and a pair of fixed and cont-inually open orifices opening from. said firstnamed outlets into said auxiliary outlet and open able to bleed fluid from said first-named outlets to said. auxiliary outlet at points between said valves and said pressure determining means.

3. A control device comprising a casing enclos ing a chamber, a fluid inlet passageway to said chamber, a pair of outlet passageways and a bleed passageway in said casing, a pair of ducts leading from. said chamber to said outlet passage" ways a pair of valves for controlling fluid flow through said ducts, a roclrable lever operatively connected to said valves and operable upon rock-j ing movement to open one of said valves and to close the other of said valves, means to move said. lever, a pair of check. valves positioned in said. ducts and operable to determinethe pres-'' sure of fluid discharging therethrough, a pair oi bleed orifices opening from. said ducts into said: bleed. passageway, and said bleed orifices being operable to permit discharge of fluid at pressures below that at which said check valves are opened.

4. A control device comprising a casing enclosing a chamber, a fluid inlet passageway to said chamber, a pair of outlet passageways and a bleed passageway in said casing, a pair of ducts leading from said chamber to said outlet passageways, a pair of valves for controlling fluid flow through said ducts, a rockable lever operatively connected to said valves and operable upon rocking movement to open one of said valves and to close the other of said valves, means operable upon predetermined movement to move said lever with a snap action, means to hold said lever at its limit of movement until said operating means has moved through substantially said predetermined movement, a pair of check valves positioned in said ducts and operable to determine the pressure of fluid discharging therethrough, a pair of bleed orifices opening from said ducts into said bleed passageway and said bleed orifices being operable to permit discharge of fluid at pressures below that at which said check valves are opened.

5. A control device comprising a casing enclosing a chamber, a fluid inlet passageway to said chamber, a pair of outlet passageways and a bleed passageway in said casing, a pair of ducts leading from said chamber to said outlet passageways, a pair of valves for controlling fluid flow through said ducts, a rockable lever operatively connected to said valves and operable upon rocking movement to open one of said valves and to close the other of said valves, means operable upon pre determined movement to move said lever with a snap action, a friction spring operable to hold said lever at its limit of movement until said operating means has moved through substantially said predetermined movement, a pair of check valves positioned in said ducts and operable to determine the pressure of fluid discharging there through, a pair of bleed orifices opening from said ducts into said bleed passageway and said bleed orifices being operable to permit discharge of fluid at pressures below that at which said check valves are opened.

6. A control device comprising a casing enclosing a chamber, a fluid inlet passageway to said chamber, a pair of outlet passageways and a bleed passageway in said casing, a pair of ducts leading from said chamber to said outlet passageways, a pair of valves for controlling fluid flow through said ducts, a rockable lever operatively connected to said valves and operable upon rocking movement to open one of said valves and to close the other of said valves, a bifurcated projection extending laterally from said lever in a plane substantially normal to the axis of the levers fulcrum, a second lever movabl between and en gageable with the prongs of said bifurcated projection and operable to rock said first-named lever, means operable upon predetermined movement of said second lever to cause th same to move with a snap action thereby to rock said first-named lever with a snap action, a friction spring operable to hold said first-named lever at its limit of movementuntil said second lever has moved the distance between the prongs of said bifurcated projection, a pair of check valves positioned in said ducts and operable to determine the pressure of fluid discharging therethrough, a pair of bleed orifices opening from said ducts into said bleed passageway and said bleed orifices being operable to permit discharge of fluid at pressures below that at which said check valves are opened.

7. A control device comprising a casing enclos ing a chamber, a fluid inlet passageway to said chamber, a pair of outlet passageways and a bleed passageway in said casing, a pair of ducts leadin from said chamber to said outlet passageways, a pair of valves for controlling fluid flow through said ducts, a rockable lever operatively connected to said valves and operable upon rocking movement to open one of said valves and to close the other of said valves, a bifurcated projection extending laterally from said lever in a plane substantially normal to the axis of the levers fulcrum, a second lever movable between and engageable with the prongs of said bifurcated projection and operable to rock said first-named lever; a third lever, a member pivoted between said second and third levers, a spring operatively connected to said third lever, said pivoted member being held compressively biased between said secondand third levers and operable to transmit a biasing thrust to said second lever; said spring,

said third lever, and said pivoted member being operable upon movement of said second lever to an overcenter position to move said second lever through the remainder of its movement with a snap action thereby to rock said first-named lever with a snap action, a friction spring operable to. hold said first-named lever at its limit of move-- ment until said second lever has moved the distance between the prongs of said bifurcated projection, a pair of check valves positioned in said ducts and operable to determine the pressure of fluid discharging therethrough, a pair of bleed orifices opening from said ducts into said bleed passageway and said bleed orifices being operable to permit discharge of fluid at pressures below that at which said check valves are opened.

8. A control device comprising a casing enclosng a liquid receiving chamber and having an inlet and an outlet, a valve for controlling liquid flow through said outlet, means to open and close said valve, an auxiliary bleed passageway in said casing; a diaphragm type check valve comprising a cylindrical cavity and a sliding piston theren, a flexible resilient diaphragm closing said cavity, aspring urging said piston against said diaphragm, an annular cavity on the side of said diaphragm opposite said piston, a transverse passageway opening at one end into said annular cavity and at the other having a restricted openmg into said bleed passageway and having in its central portion an opening communicating with said outlet, an outlet passageway, a second transverse passageway opening into said outlet passageway at one end and through the central portion of said annulus against said dipahragm at the other end, and said check valve being operable to determine the pressure of liquid discharging from said outlet.

EARNEST J. DILLMAN.

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