US2245834A

US2245834A - Safety control device

Info

Publication number: US2245834A
Application number: US261392A
Authority: US
Inventors: Hubert T Sparrow
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1939-03-11
Filing date: 1939-03-11
Publication date: 1941-06-17
Anticipated expiration: 1958-06-17

Description

June 17, 1941. H. T. SPARROW SAFETY CONTROL DEVICE Fileci March 11, 1959 iinvefitor Huber T. Sparrow- B flee- A! attorney F 3 .m a: 5 8 a N Mrm v m:

Patented June 17, 1941 SAFETY CONTROL DEVICE Hubert '1. Sparrow, Minneapolis, Minn assignor to Minneapolis-Honeywell Regulator Minneapolis, Minn., a corporation oi Company, Delaware Application March 11, 1939, Serial No. 261,392 I 6 (llaims. (Cl. 137-139) The present invention relates to a safetycontrol device and more particularly to a gas valve for shutting oif the flow of gas in the event of the pilot burner becoming extinguished.

In gas burning systems, it is desirable to provide some means for interrupting the flow of gas to the main burner whenever the pilot burner is extinguished. This means may take the form of either a valve in the main gas line or a switch which is in the controlling circuit of an electrically controlled valve in the main as line. One common form of such a device is an electromagnetically controlled valve, the electromagnet of which is energized by a thermocouple exposed to the pilot burner flame. The device is so arranged that upon the pilot iiame being extinguished to cool the thermo-couple, the electromagnet is deenergized which permits the valve to move to closed position. The valve cannot be reopened until the device has been manually reset. The danger arises with such a device that in the resetting operation gas will be admitted to the main burner and if the pilot burner is .not cause an explosion upon thesubsequentlighting of the pilot burner. It has accordingly been proposed'to provide means for insuring that the armature is not moved into engagement with the electromagnet upon the actuation of the reset member until the electromagnet actually holds the armature. The present invention is concerned with an improved form of such a device.

An object of the present invention is to provide' an arrangement wherein there is a control device movable between a safe and an active position and an electromagnet for holding the device in the safe position with a strain release connection between the electromagnet armature and the controhdevice and resetting means for extending this strain release connection to move the armature into engagement with the electromagnet without moving the control device from its safe position the armature and the reset means is moved back in the direction of. its original position.

.A further object of the present invention is to provide such an arrangement wherein the already lit, this gas may untilthe electromagnet holds armature'bears against a movable. member connected to the control device and (wherein the reset means is moved between the armature and the movable member to spread the armature and movable member apart.

A further object of the present invention is to provide such an arrangement wherein the control device is a valve..

A further object of the present invention is to provide an arrangement of the type set forth in the above objects in which cam means are employed to extend the strain release connection between the armature and the control device.

Other objects of the present invention will be apparent from a consideration of the accompanying specification, claims and drawing, of which Figure 1 is a schematic view of a gas burner control system employing my improved control device in the form of a valve and with the valve in closed position, and

Figure 2 is a view of the control device during the resetting operation.

Referring to the drawing for a more detailed understanding of the invention, the gas burner is designated by the reference numeral ID. This gas burner is connected by means of a pipe H to a mixing chamber I2. 'This mixing chamber is of conventional form and is utilized for mixing air with the gas going to the burner. The mixing chamber I2 is connected with a pipe l3 to the outlet of my improved control valve. The inlet of the valve'is connected by a pipe 14 with the outlet of a motorized valve IS. The inlet of the motorized valve I5 .is in turn connected to a gas supply pipe l6 leading to any suitable source of gas (not shown). The motorized valve is controlled in any suitable manner and may, if desired, be controlled by a thermostatic switch.

Located adjacent to the main burner it is a pilot burner 18. The pilot burner i8 is connected by means of a pipe l8 to the gas supply pipe l6. It will be noted that the flow of gas through pipe IE to pilot burner I8 is independent of both of the valves so that the pilot burner I8 is normally constantly burning. It is obviously very desirable that, when valve I5 is open, no gas flows to the main burner unless the pilot burner 18 is burning. The present invention is concerned with means for interrupting the flow of gas if the pilot burner is extinguished at any time.

' The improved control device of the present I invention comprises a valve body 25 having an inlet connection 26 and an outlet connection 21. Within the valve body 25 between the inlet and outlet connections is a valve seat 28 upon which a gas valve 29 seats. Secured to the valve body 25 is a cylindrical housing member 30. The

' valve body 25 and the housing member 30 are provided with aligned apertures 32 and 33. A

diaphragm 34 is located between the valve body and the housing member 30 and servesto prevent passage of gas through the apertures 32 and 33. It is to be understood that the housing member 36 is secured to the valve body 25 by a suitable fastening means (not shown).

The bell-crank lever 35 is pivotally mounted at 36 to the housing member 36. The lever 35 has a downwardly extending arm 31 which extends through the diaphragm 34 being secured thereto by a .gas tight connecting means 39. Such connecting means may take the form of clamping nuts disposed on opposite sides of the diaphragm. The arm 31 is pivotally connected to the valve 29 at 46. A biasing spring 4| is connected at one end to the arm 31 and at its other end to an ear 42 projecting from the valve body 25. The biasing spring 4| tends to rotate the bell-crank lever 35 in a clockwise direction to move the valve 29 ofi of the seat 26.

On top of the cylindrical housing member 36 an inverted cup shaped housing member 65 is mounted. The two housing members 36 and '35 are connected together by means of a screw .thimble 46. Secured to the housing member 45 by any suitable means is a U-shaped core 48 of magnetic material. low resistance windings 49 and 56 which are electrically connected in series by conductors A thermo-couple 52 is located in the pilot burner iiame and is connected bysuitable low resistance conductors 53 and 54 to the coils 49 and 56.

Associated with the electromagnet constituted by the core 48 and the windings 49 and 56 is an" armature 56. The armature 56 like the core 88 is of magnetic material of relatively high permeability. The armature 56 is provided atv its righthand end with spaced tongues 51 which straddle a pivot pin 58 secured to the housing member 36. The armature 56 is thus pivotally mounted to the housing member 36. By reason of the loose pivotal connection affordedby the tongues 51 and the pin 58, it is possible to move the armature 56 into very close engagement with the core 48. A spring 66 is connected to the left-hand end of armature 56. The other end of spring 66 is secured to the cylindrical housing member 36. The spring 66, like spring 4|, is a tension spring and serves to bias the armature 56 downwardly.

The bell-crank lever 35 is provided with a curved horizontal arm 62. When the armature 56 is released by the electromagnet, the spring 66 urges the armature 56 into engagement with arm 62 of the bell-crank lever 35. The spring 66 is sufficiently strong that it is able to rotate the bell-crank lever 35 against theaction of spring 4| so as to move valve 29 against-its seat 28. Thus, whenever the electromagnet constituted by core 68 and windings 69 and 56 is deenergized, the valve is moved to closed position through the biasing action of spring 66 acting through armature 56 and bell-crank lever 35.

As is well known, a thermo-couple is capable of generating only a very limited amount of electromotive force. Consequently, in spite of the high permeability of the core 66 and the armature 56 and in spite of the relatively high conductivity of the conductors associated with the thermo-couple, the electromagnet is incapable of exerting a sufiicient pull upon armature 56 to I move the same against the action of biasing spring 66. Consequently, it is necessary to provide some means for reengaging the armature and electromagnet when the same are separated as a result of the pilot burner becoming extinguished. This means takes the form of a plunger Located on this core arev 66 which extends through the wall of the cylina button 61 at the outer end thereof and interposed between the wall of chamber 36 and the button 61 is aspring 68. This spring 68 is a compression spring and serves to urge the plungv er outwardly. The outward movement is limited by a pin 16 secured to plunger 66. At its inner end, the plunger 66. carries a cylindrical disc 1|. This disc is slotted at 12 and into this slot extends a member 13 of rectangular crosssection secured to plunger 66. are provided for preventing a transverse movement of the disc 1|. By reason of the square cross-section of member 13 the disc 1| cannot rotate. By reason of the slot 12, however, the disc 1| is free to slide up and down on the member. 13 for a purpose to be subsequently described.

Let it be assumed that the elements are in position shown in Figure 1. Upon button 61 being pushed inwardly to move the plunger 66 inwardly, disc 1| moves inwardly separating the armature 56 and the arm 62 of lever 35. The arm 62 and member 1|, in effect, constitute two cooperating cam surfaces so that as member 1| is moved to the right it rides on the curvedsurface of arm 62, sliding upwardly on member 13 to move armature 56 against the electromagnet.

When the armature engages the electromagnet, the various elements are in the position indicated in Figure 2. It will be noted that during this process, the valve 29 has remained in engagement with the seat 26 so that no gas is permitted to flow. The operation which has takenplace in shifting the apparatus from the position shown in Figure l to that shown in Figure 2 in effect constitutes an extension of the strain release connection between valve 29 and armature 56. This strain release connection is constituted by the spring 4| and the lever 62 which bears against the armature 56 so that upon-any upward movement of armature 56, valve 29 is normally similarly moved. Thus the valve .29 is normally connected to the armature 56 so as to always assume a position corresponding to the armature. When the plunger 66 is moved inwardly, however, this normal relation between the armature 56 and the valve 29 is interrupted and the connection between them is extended so that in spite of the armature 56 being moved into engagement with the core 68, the valve 29 remains in engagement with the seat 28.

If the pilot burner is not properly lighted when shown in Figure 2, the disc 1| will merely retrace the path followed during the inward movement of plunger 66 so that the parts will again assume the position shown in Figure 1 without the valve 29 being opened at any time. Let it be assumed, however, that the pilot burner is ign ted and that the thermo-couple 52 is suificiently hot to energize windings 69 and 56. Under these conditions, when the plunger 66 is released to permit its return by the biasing spring 66, the armature 56 remains in engagement with the electromagnet. As the disc 1| moves to the right, the spring 6| is free to rotate theibell-crank lever 35 until the left-hand end of arm 62 engages or substantially engages the armature 56.

From the foregoing description, it will be apparent that the valve is opened only after the pilot burner has been relighted and cannot be reopened until such time. I have'thus provided Suitable means the in nature and which insures that the control device will not be moved to its active position in the presence of a condition which would make the movement of the control device to its active position undesirable. 7

While I have shown .a specific embodiment of the invention, it is to be understood that this is for purposes of illustration-onlyand that the invention is limited only by the scope of the appended claims. 7

I claim as my invention:

1. In combination, a control device, an elongated casing therefor, said control device being movable longitudinally of said casing-between a safe. position and an active position and being biased to said active position, a control housing secured to said casing, an electromagnet within said control housing, an armature supported for movement into and out of engagement with'said electromagnet, said armature when engaged with said eleetromagnet extending substantially parallel to said casing, a movable member connected armature to move said control device to its safe position when said armature moves to its released position, said movable. member having a surface inclined with respect to a cooperating surface of said armature, and resetting means including a device reciprocable longitudinally of and between said armature and easing, said re-' to said control device and positioned by said 3 for movement into and out of engagement with said electromagnet, said armature when engaged with said electromagnet extending substantially parallel to said casing, a movable member connected to said valve and positioned by said armature to move said valve to closed position when said armature moves to its released position, said movable member having a surface inclined with respect to a cooperating surface of said armature, and resetting means including a device reciprocable longitudinally of and between said 7 armature and valve casing, said reciprocable device being operable when moved inwardly of said. control housing to enter between said cooperatingsurface of the armature and the inclined surface of said movable member to force them apart so as to move the armature into engagement with the electromagnet while holding said valve closed until said armature has been held by said magnet and said reciprocable device has been moved back in the direction of its original position.

4. In combinationfa valve biased to open po- I sition, a casing therefor, said valve .being pivotally mounted and movable within said casing between open and closed positions, acontrol housing secured to said casing, an electromagnet within said control housing, an armature supported for pivotal movement into and out of ciprocable device being operable when moved inwardly of said control housing to enter between said cooperating surface of thecarmature and the inclinedsuriace of said movable member to force them apart so as to move the armature into engagement with the electromagnet while holding said control device in said safe position until said armature has been held by said magnet and saidreciprocable device has been moved-back to. said control device and positioned by said" armature to'mo ve said control device to its safe position when said armature moves to its released position, and resetting means including a device reciprocable longitudinally of and between said armature and easing, said movable member and said reciprocable device being formed to provide cooperating cam surfaces such that said reciprocable device is operable when moved inwardly of. said control housing so as to enter between said armature and said movable member to force them apart so as to move the armature into engagement with the electromagnet while holdingsaid control device in said safe position until said armature has been held by said magnet and said reciprocable device has been moved back in the direction of its original position.

3. In-combination, a valve, an elongated casing therefor, said valve being movable-longitudinally or said casing between open and closed positions and being biased to open position, a control hous-I ing secured to said casing, an electromagnet with engagement with said electromagnet, said armature when engaged with said electromagnet extending substantially parallel to the path of movement of said valve and when not so engaged.

extending at an angle to the path of movement of the valve, a movable member connected to said valve and positioned by said armature to move said valve to closed position when said armature moves to its released position, said armature and movable member extending at an angle to each other when said armature is out of engagement with said electromagnet, and resetting means including a device reciprocable longitudinally of and between said armature and valve casing, said reciprocable device being operable when moved inwardly of said controlhousing to enter between said armature'and said movable member to force them apart so as to move the armature into engagement with the electromagnet while holdingsaid valve closed until said armature has been held by said magnet and said reciprocable device has been moved back in the direction of its original position.

5. In combination, a valve biased to open position, a casing therefor, a control housing seenter between said armature and the curved arm of saidv lever to force them apart so as to move in said control housing, an armature. supported cured to said casing, an electromagnet within.

said control housing, an armature supported for pivotal movementinto and out of engagement with said electromagnet, a pivotally mounted bell crank lever having means connected to said valve to move the same over a path substantially parallel to the armature when the latter is engaged with said electromagnet, said lever having an arm within said housing curved towards said armature and positioned by said armature to move said valve to closed position when said armature moves to its released position, and resetting means includinga device extending into said control housing and reciprocable longitudi-' nally, of and between said armature and valve casing, said'reciprocable device being operable when moved inwardly oii said control housing to the armature into engagement with the electromagnet while holding said valve closed until said armature has been held by said magnet and said reciprocable device has been moved back in the direction of its original position.

' 6. In combination, a valve biased to open position, an elongated casing therefor, a control housing secured to said casing, a pivotaily mounted bell crank lever having one arm connected to said valve :to move the same longitudinally of said valve casing and the other arm projecting into said control housing, a member pivotally mounted at a point within said control housing spaced from the pivot point of said lever and biased into engagement with said other arm of said lever" to move said valve to closed position against its bias, holding means in said control housing for said member, and resetting means inal position.

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including a device reciproca/ble longitudinally of and between said pivoted member and said other arm of the bell crank lever, said reciprocable de-- HIIJ'BERT T SPARROW.