US2275340A - Resetting means for safety shutoff devices - Google Patents

Description

March 3, 1942. P. L. BETZ 2,275,340

RESETTING MEANS FOR SAFETY SHUTOFF DEVICES Filed Jan. 31, 1940 Patented Mar. 3, 1942 RESETTING MEANS FOR SAFETY SHUTOFF DEVICES Paul L. Betz, BaltimoreQMd, assignor to Consolidated Gas Electric Light and Power Company Baltimore, Md., a corporation of Maryland Application January 31, 1940, Serial No. 316,676

7 Claims.

l'his invention relates to resetting means for shut-off devices, and more particularly to re setting means for shut-off devices that are elec tromagnetieally controlled.

In automatic systems for the operation of gas burners, it is necessary to have a pilot or ignition flame at or adjacent to the gas burner to insure only. In this case. gas for the pilot or ignition flame is supplied by a connection ahead of the shut-off device. .Another method of installing the shut-ofi device is to make the gas connection for the pilot or ignition flame to the supply line after the shut-off, whereby closure of the shutciI device prevents the flow of gas to the pilot burner as well as to the main burner. This latter system is known as a complete shut-Off I system.

It is an object of this invention to provide a resetting means for shut-off devices so that when the shut-oil valve has closed, resetting'can be accomplished only if a proper ignition flame exists at the pilot burner.

A further object of the invention is to provide resetting means which permits the use of a shutoff device for complete shut-01f of the burner system, and includes means for supplying gas to the pilot burner from the inlet side of the shutoiI device during the resetting operation and from the outlet side of the shut-01f device after the shut-off valve is open.

A further object of the invention is to provide a visual indication or means for operating an electric circuitincluding signaling means when the shut-off device operates.

Another'object of the invention is to provide resetting means that is certain in operation, simple in construction and durable.

Other objects will appear as the description of the invention proceeds.

The invention is capable of receiving a variety of mechanical expressions one of which is illus-' trated on the accompanying drawing,'but it is to be expressly understood that the drawing is for purposes of illustration only, and is not intended as a definition of the invention, reference being had to the appended claims for that purpose.

Referring in detail to the accompanying drawing wherein the same reference characters are employed to designate corresponding parts in th several figures: I

Fig. l is a diagrammatic elevation to illustrate an embodiment of the invention;

Fig. 2 is a vertical axial section of this embodiment on a larger scale;

Fig. 3 is-a top plan view of the structure of Fig. 2; and

Fig. 4: is a cross-section on the line Q- of Fig. 2.

Referring to Fig. l, the main gas burner is indicated at I, and the conduit 2 is the fuel supply conduit therefor. For purposes of illustration, a shut-off device in the form of a valve of the thermoelectric type is indicated at 3', and is here shown as installed in conduit 2 between the gas supply and main burner I. Associated with main burner l is a pilot or ignition burner 4 having a fuel supply conduit 5. A thermocouple is shown at 6 and is heated by the pilot or ignition flame from burner 4 to energize an electromagnet winding diagrammatically indicated at "i (see Fig. 2) The arrangement shown in l is for complete shut-0E and upon extinction of the flame at pilot burner 4 and subsequent closure of the valve or shut-oii device 3. all gas flow is thereby interrupted.

Referring now to Fig. 2, the details of construction of a preferred embodiment of the in vention are illustrated. The shut-off device is indicated at 3, having inlet and outlet chambers ii and respectively. Valve port it is interposed between chambers 8 and 9 so that the flow or" gas may be interrupted upon closure of valve mem ber A spring [2 is shown in 2 as biasing valve member Ii toits closed position. A valve stem it) extends from said valve member and is attached to the armature M of an electromagnet, so that when armature I4 is in the raised position indicated in Fig. 2, valve H is open and gas may flow between inlet and outlet chambers 8 and 9. Said electromagnet includes a U-shaped magnetizable element l5 having pole pieces cooperating with the armature l4. Electromagnet winding 7 may be connected to any suitable source of electromotive force, in the illustrated embodiment to a thermocouple 6 subjected to the pilot flame. The electromagnet winding 7 surrounds at least one leg of U-shaped element l and is stationarily mounted in any suitable way, while said U-shaped element 5 is freely movable with respect thereto in the direction ofthe axis of the winding. As shown in Fig. 2, U- shaped element |5 is mounted on or has attached thereto a cross member H; which is urged upward, as viewed in the figure, by one or more springs H which together are stronger than spring |2. Stem i8 is attached to cross member l6 and passes through the casing of the shut-off device, and is provided with suitable packing to prevent the leakage of gas.

It is thus seen that when valve member H is in its closed position, armature I4 is normally separated from the pole pieces of U-shaped element i5 due to the combined action of springs l2 and H. In order to open the valve and maintain the valve member in open position, it is first necessary to establish the pilot flame at burner i to supply heat to thermocouple 6 and thereby energize electromagnet winding 1. Manual movement of stem is downward as viewed in Fig. 2 causes U-shaped element ii to be moved toward armature 54 until contact is established between the pole faces and the armature, in doing which springs are compressed, and if electromagnet winding i is now receiving sufficient energy from thermocouple B, armature it will be held to the pole faces of element i5, and upon release of stem 68 the spri gs ll will move element i5, armature i4, valve stem l3 and valve member i| upward against the force exerted by spring i2, thereby opening the art it between chambers 8 and 9. In doing this, valve spring i2 is compressed so that upon cooling of thermocouple 6 and deenergization of winding 1, armature it will be moved away from the pole faces of element 55, thereby permitting valve Ii to close.

Jfhe description given so far of Fig. 2 covers a resetting means suitable for a safety shut-cit device when used where interruption of the gas flow to the main burner only is required. In this case, the conduit 5 to pilot burner 4 may be connected to conduit 2 on the inlet side of the safety shut-off device, or may be tapped directly into casing 3 into chamber 8.

Where complete shut-off is required, the resetting means described so far is necessary together with a valving arrangement interlocked with the operation of stem iii. For this function,

any suitable valving arrangement may be employed, but for the purposes of exemplification, a 3-way plug cock is illustrated. This 3-Way plug cock comprises a movable plug 23 which fits a stationary housing member provided with three port connections, 20, 22 and 2|. Plug 23 is provided with two passages one of which is indicated at 2|a and the other of which is indicated at 2|b (Fig. 4). Passage 2|a provides a path for the flow of gas from port 2| to port 22, and when plug 23 is moved away from the position shown in the drawing, this path for the gas is interrupted and another path is estab. lished from port 20 to port 22 by means of the passage 2|b. Port 2|, designated To outlet," communicates with a conduit 21 leading to the outlet side 9 of valve 3. Port 20, designated To inlet, communicates with a conduit 21a leading to the inlet side 8 of valve 3. Port 22, designated To pilot" is connected to the fuel supply conduit 5 leading to pilot burner 4. Thus said plug cock provides, in one position of plug 23, for the flow of gas from the inlet sideof valve 3 through conduit 27a, port 20, passage 2|b to port 22, conduit 5 and pilot burner 4, and in the other position of plug 23 for the how of gas from the outlet side of valve 3 through conduit 21, port 2|, passage 2|a to port 22, conduit 5 and pilot burner 4.

Referring to Fig. 2, movement of plug 23 is accomplished by means of a lever 24 which is suitably attached to the extremities of tapered plug 23, as by screws 25, and which has an extension 26 which projects over the outer extremity of stem |8. When valve H is closed, lever 24 may be depressed manually and extension 26 engages stem 8 to move the pole pieces of U- shaped element l5 into contact with armature $4. This movement of lever 24 causes plug 23 to establish the flow of gas from the inlet side 8 of valve 3 throughport 20 to port 22, conduit 5 and pilot burner l. While still holding lever 24 in this depressed position, it is now possible to light the pilot flame at burner 4, which causes thermocouple t to be heated. When thermocouple 6 is h d sufficiently, electromagnet Winding i will ergized and will cause armature t to ad tothe pole pieces or" element i5. Upon i c g lever 26,'plug 23 may move to the positio n in Fig. 2 under the action gs (not shown), and springs ve m mber ii, armature i4 element i5 t" ore upwardly as viewed in the figure, spring being compressed, and stem H: ass r en at of lever 24 to its position ior utlet side 8 of the shut-oif device .er. The movement of tapered manually maintained position steady running position shown the flow of gas to burner i of the shut-oif device by way tablishes the flow of gas to pilot burner 4 from the outlet side 9 of the shut-oft device by me of conduit 21, port 2|, passage 2|a, port 22 and conduit 5 to pilot burner 4.

Should the flame at burner 4 be extinguished, thermocouple 5 will cool and electro magnet winding will be deenergized. U-shaped magnetizable element l5 can then no longer hold armature H by magnetic attraction against the action of spring l2, and these members will separate causing valve member H to close port i0, Inasmuch as the gas flow from port 22 to pilot burner 4 comes from the outlet side 9 of shutoif device 3, closure of valve interrupts the flow of gas to both the main burner and the pilot burner 4.

Considering Fig. 2, it will be seen that in the steady running position there shown, the action of springs ii is upward and opposite to that of spring i2, and when armature I4 is released from the pole pieces of element |5, upon deenergizing electromagnet winding 1, the opposing effect of spring I2 is reduced and springs may then produce an additional outward movement of stem |8. Thus closure of valve member may be indicated visually outside the valve casing by a change in position of stem IE, or if desired, the additional movement of stem I8 upon its release and closure of valve I may be utilized to operate electrical contacts in any suitable circuit to operate signal or other devices therein. as; indicated diagrammatically by the leads 28. or the movement of stem |8 may be used to operate any suitable switch or contact device, as for example a mercury tube type switch.

From the above, it is seen that the present invention provides a resetting means for safety shut-off devices where the devices are used for either the complete or the partial shut-off of in Fig. 2 i i from e i of port and the gas supply. In addition, visual indication is given, or electrical means may be operated, upon closure of the valve of the shut-off device. The

above description has been given for a thermoelectrically operated shut-off device, but as will be obvious to those skilled in the art this is for purposes of illustration only, as any other suitable type of 'energization of the electromagnet may be employed and similar results will be obtained. Other forms of safety control devices may be used, and changes may also be made in the form of the valve I I or the plug cock, as well as in other details of construction, arrangement, proportion, etc., of parts without departing from the spirit of the invention. Reference is therefore to be had to the appended claims for a definition of the invention.

, What is claimed is:

1. In a safety control device of the type employing an electromagnet for holding the device in open position and requiring manual resetting to open position, the combination of an armature connected to a controlling member, resilient means for biasing said armature and controlling member to closed position, a movable U-shaped magnetizable element having pole pieces cooperating with said. armature, a stationary electromagnet winding surrounding at least one leg of said element and arranged to permit the free movement of said element therethrough, said winding being adapted when energized to cause said element to hold the armature and the controlling member in open position, resilient means stronger than said first-named resilient means for biasing said U-shaped element iygether with said armature to open position, said secondnamed resilient means acting in opposition to said first-named resilient means and operating to hold said first-named resilient means under compression when said armature is holding the controlling member in open position, and resetting means for manually moving said pole pieces into engagement with said armature when said armature is in the closed position of said controlling member against the action of said lastnamed resilient means, whereby upon resetting said pole pieces may be moved manually into engagement with said armature and upon the manual release of said resetting means said U-shaped element, armature and controlling member may be moved to open position by said iastmained resilient means provided said winding is properly energized.

2. In safety control device for gas valves of the type employing an electromagnet for holding the valve in open position and requiring manual resetting to return the valve to open position, the combination of an armature connected to the valve, a movable U-shaped magnetizable element having pole pieces cooperating with said armature, a stationary electromagnet winding surrounding at least one leg of said element and arranged to permit the free movement of said element therethrough, said winding when energized being adapted to hold said armature and element in engagement and said valve open, resilient means for closing said valve upon deenergization of said winding, a manual resetting device for resetting said valve to open position, said resetting device comprising resilient means stronger than said first-named resilient means and acting in opposition thereto for biasing said il-siiaped element together with its armature against the tension of said first-named resilient means to the open position of the valve, means for manually moving said U-shaped element into contact with said armature when the armature and the valve associated therewith are in the armature when the valve is closed, said secondnamed resilient means, upon movement of said armature and U-shaped element to the open position of said valve, cooperating with said flowcontrolling device to assure that said pilot burner is connected :to the outlet side of said valve.

3. In a safety control device of the type employing an electromagnet for holding the device in open position and requiring manual resetting to open position, the combination of an armature connected to a controlling member, a. stationary electromagnetic winding, a m'agnetizable element associated with said winding to provide the poles of an electromagnet and cooperating with said armature, said element being adapted to move with respect to said winding in the direction of the axis thereof, said winding being adapted when energized to cause said element to hold said armature in contact therewith, resilientthe valve in open position and requiring manual resetting to return the valve to open position, the combination of an armature operatively conneced to the valve, a stationary electromagnetic winding, a magnetizable element associated with said winding to provide an electromagnet and cooperating with said armature, said element being adapted to move with respect to said winding in the direction of the axis thereof, resilient means for moving said valve to closed position when said armature is released from said element, and a second and stronger resilient means cooperating with said element for moving said element in the opposite direction to move said armature and valve therewith to open position and compress said first-named resilient means when said winding is energized.

5. A device according to claim 4 which also includes a valve for controlling the flow of gas to said pilot burner from either the inlet or the outlet side of said first-named valve, and said second-named resilient means cooperating with said last-named valve for holding said lastnamed valve in its position for admitting gas to said pilot burner from only the outlet side of said main valve.

6. A device according to claim 4 which also includes a valve for controlling the flow of gas to said pilot burner from either the inlet or the outlet side of said first-named valve, and manually operable means associated with said lastnamed valve and cooperating with said element for moving said element into contact with said armature, said last-named means establishing communication between said pilot burner and the inlet side of said, first-named valve only when said element is being manually held against the tension of said stronger resilient means.

7. A device according to claim 4 which also includes a valve for controlling the flow of gas to said pilot burner from either the inlet or the outlet side of said first-named valve, means -associated with said element and with said second-named valve whereby said second-named valve is in one or the other of its positions depending upon whether said element is moved into engagement with said armature against the said first named valve is closed.

v PAUL L. BETZ.

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