US2632504A - Burner control valve - Google Patents

Description

R E NEWELL, JR

BURNER CONTROL VALVE Filed Aug 5, 1949 III I 1 March 24, 1953 INVENTOR. 203527 E. NEWELL,JR. BYZ Z 21/ w l a HTTOPNE Patented Mar. 24, 1953 UNITED STATES PATENT OFFICE BURNER CONTROL VALVE Robert E. Newell, Jr., Irwin, Pa.

Application August 5, 1949, Serial No. 108,683

6 Claims.

My invention relates to thermally-actuated control devices that are especially suitable for use with the-safety pilots of gas burners.

One object of the invention is to provide a flame-responsive assembly for such safety pilots, that will be cheaper to manufacture; that will be stable at a given setting, and which may be operated by a small pilot flame having a single jet or wide flame adapted to contact the thermal device and to ignite the main burner, simultaneously.

A further object is to provide in said thermal device or assembly an external thermal element near to the main heating burner and contacted by the pilot flame, with means for communicating its movement to an internal operating lever, extending to a point within a valve chamber, remote from the burner, without the use of sliding parts, gland pins, packing, etc.

Although my thermal device may be used to operate various types of valved mechanism, either gradual or snap-acting, I shall, for the purpose of this application, describe a manually reset valve of the style shown in Robert E. Newell application Serial No. 639,965, filed January 9, 1946 (Patent 2,499,253).

In the accompanying drawing: Figure l is a sectional view of my control device, showing its relationship to a gas valve and a burner; Fig. 2 is a face view of the bracket member at the forward end of the structure of Fig. 1; Fig. 3 is valve body or housing 7 that contains a valve 8 for controlling flow of gas through the valve body to a main burner 9, it being understood that a suitable piping connection will be pro-' vided between the valve body and the burner. The valve 8 is carried by a valve stem It and is yieldably held on its seat II by a compression spring l2. s 4

A burner tip I 3 which may suitably be of stainless steel has a hole or port M of generally circular form and is also provided with a relatively narrow slot I5 that extends back-wardly from the port l4. pipe it supported upon the valve body and communicating with a port I"! through which gas may be supplied from any desired source to the pilot burner-tip l3.

A supporting tube [8 is carried by the valve body 1 and it may suitably be of cadmium-plated The tip I3 is carried by a" carbon steel. A bracket 19 is welded to the forward end of the tube l8. This bracket is of a metal having low co-eflicient of expansion, such as a nickel steel alloy. An operating lever 20 which can suitably be of chrome-nickel alloy extends through and has drive fit with the bracket 19, to prevent leakage of gas from the tube l8. At its rear end, this lever has a stem 2| which, when the apparatus is in a normal state of operation, has abutting engagement with the forward end of the valve stem II], to hold the valve 8 in its open position, for supply of gas to the main burner 9. The lever and its extension thus function as a latch.

A thermal strip or plate 22 is welded at its upper edge to the bracket [9 and near its lower edge is welded to the lever 20. Thiselement 22 is of metal such as a chrome-nickel alloy, has a high co-eihcient of expansion relative to the metal of bracket I9.

So long as a supply of gas is maintained to the pilot tip, the lever 20 will be held in the position shown in Fig. 1 and the gas valve 8 thereby held open. If the pilot flame becomes extinguished for any reason, the consequent cooling of thermal element 22 will result in tilting of the lever 20 to its dotted line position, to'release the valve stem IS and permit the valve to be closed by its spring l2. Upon relighting the pilot tip the flame through the slot 15 will reheat the thermal strip 22 and restore the lever to its valve-holding position, so that when the valve 8 is'pulled open its stem l9 and the lever stem 2| will againbecome interengaged.

Should the burner tip become clogged, the slot IE will become clogged before the port I4 becomes clogged. This will result in cooling of the strip 22 and consequent closing of the valve 8 while the flame or ignition jet at I4 is still burning. A similar safety result will occur in case of an extreme drop in gas pressure, since the sheet of flame that issues from the narrow slot l5 will be extinguished before failure of the jet at the larger port It.

In some types of pilot flame controls there has been a tendency for the'pilot flame to be cut off unnecessarily, owing to drafts, over-firing of the heater, defective or over baffled flues, etc.

This objection is overcome by my present invention, owing to the fact that a considerable period of time is required for the thermal strip to become cooled to a point at which it will operate the control lever 20, and to the fact that the thermal heating and the ignition flames are compact and located close to the main burner where,

in the average combustion chamber, fresh secondary air keeps the pilot flame supplied with oxygen.

The present thermal device is cheaper to manufacture due to the smaller amount of expensive alloys required. Because of the high amplification of movement of the operating lever 3, a very small thermal strip is required (being in actual practice only about long), in order to obtain a movement of .040 to .060 at the free end of the operating lever.

Due to the small size and lightness of the thermal element, and the fact that it is not secured to the large mass of the main burner, no compensation is needed to reduce the operating time.

It will be understood that the-thermal device can be used also to operate electrical switches, or other control devices.

I claim as my invention:

1. A thermally-operated control device comprising a housing, a gas valve that is mounted in the housing and has a stem that is movable to open and close the valve, a tube connected to the housing and open at its rear end, for access to the valve stem, a bracket rigidly secured to the forward end of the tube, a latch lever supported intermediate its ends by the bracket and extending through the bracket and disposed within the tube into position to eiTec't engagement with the valve stem and releasably hold the valve off the valve seat, a thermal strip having a high coefiicient of expansion relative to the bracket secured at one end to the bracket and secured near its other end to the forward end of the latch lever and extending transversely thereof, and a pilot flame tip positioned to ignite a gas burner and to heat the thermal strip, whereby heating and cooling or" the strip will efiect rocking of the latch lever on the bracket, to move the inner end of the lever into and out of latching position relative to the valve stem.

2. A thermally-operated device as recited in the preceding claim, wherein the tip has a jet opening for igniting the burner and a slot for producing a thin, wide flame for heating the thermal strip.

3. A thermally-operated device comprising a tubular support adapted for connection at its rear end to apparatus to be controlled, and open at its rear end, a bracket extending'across the forward end of the support and having a wall portion deflected into the support for a substantial distance, an operating lever extending through and pivoted on the said wall portion and extending through the tubular support, and a thermally-responsive element secured to an edge portion of the bracket and to the adjacent end of the lever, whereby upon heating of the element by a flame the lever will be rocked relative to the tubular support.

- 4. A thermally-operated device comprising a tubular support adapted for connection at its rear end to apparatus to be controlled, and open 4 at its rear end, a bracket extending across the forward end of the support and having a wall portion deflected into the support for a substantial distance, an operating lever extending through and pivoted on the said wall portion and extending through the tubular support, a thermally-responsive element secured to an edge portion of the bracket and to the adjacent end of the lever, whereby upon heating of the element by a fiarne the lever will be rocked relative to the tubular support, and a gas pilot burner carried by the said bracket, in position to heat the thermal element, the burner having an opening which directs asheet of flame against the said element and a jet flame in a direction away therefrom.

5. A thermally-operated device comprising a gas valve chamber, a gas valve therein, for controlling flow of gas through the chamber, a spring normally urging the valve to its closed position, a stem on the valve and having one of its ends protruding through a wall of the chamber, a tube having one end tightly connected to the said wall, in circumferential relationship to the protruding end of the stem, a bracket plate extending across the forward end of the tube and snugly connected thereto, the plate being provided with a central perforation, a latch lever arranged in generally end-to-end relation with the projecting extremity of the valve stem and extending through said perforation, with a snug fit, and a thermal strip rigidly secured at one end to the forward end of the tube and extending transversely or the lever and rigidly secured to the extremity of the lever, adjacent to the other end of the strip, whereby heating and cooling of the strip wiil rock the lever on the plate.

6. A thermally-operated device comprising a tubular support adapted for connection at its rear end to apparatus to be controlled, and open at its rear end, a bracket secured across the forward end of the support and having a hole therethrough, the bracket serving as an end wall for the tubular support, an operating lever extending through the hole and pivoted on the bracket,

- and extending lengthwise through the tubular support, and a thermally-responsive element rigidly secured to the bracket and extending from one edge thereof and rigidly secured to the adjacent end of the lever, whereby upon heating of the thermally-responsive element by a flame, the lever will be rocked relative to the tubular support.

ROBERT 'E. NEWELL, JR.

REFERENCES CITED The following references are of, record in the file of this patent:

UNITED STATES PATENTS 60 Number Name Date 1,966,735 Sackett July 17, 1934 1,980,129 Walker et a1. l Nov. 6, 1934 2,015,318 Schnepp et al Sept. 24, 1935 2,068,429 Mustee Jan. 19, 1937

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