US2348965A - Thermostatically operative valve - Google Patents

Description

May 16, 1944.

kR. J. DOUGHERTY THERMOST'PI CALLY OPERAT IVE VALVE Filed Dec; l0 1940 NN NN .N NbN //V Vf /V TOP.' foefeTJ 000s/merg;

Llatented May 16, 1944 'TnERMosTA'ricALLY OPERATIVE VAL-va Robert J. Dougherty, Ambler, Pa., assignor to John Wood Manufacturing Company, Inc.,

Conshohocken, Pa., a corporation of Delaware Application December 10, 1940,` Serial No.1369,455

1 Claim.

My invention relates to valves of the general class disclosed in Letters Patent of the United States No. 1,974,646 andNo. 1,963,043 which may be advantageously employed in controlling the :flow of gas to a burner which is part of a water heater. members of the thermostatic couple are formed of respectively diierent material, viz., a copper tube which has a highA coefiicient of expansion, and a rod of the ferrous alloy known as invar; the coeillcient of expansion of the latter being negligible within the range of temperatures to which the couple is subjected. On the contrary, in accordance with my present invention the members of the thermostatic couple are vformed oi' the same material, preferably of non-corrosive steel. Consequently, relative movements of the members ofv the couple are efl'ected solely by the degrees of temperature to which the members of the couple are repectively subjected, without anyv differential due to diil'erences oi coefilcients of expansion.

l(Cl. 158-1171) In each of the patented structures, the

valve down to theport 6 in the needle valve casing 'l from which gas is delivered through the orifice 8 into the main burner 9 undercontrol of the manually adjustable vneedle valve II. Said needle valve has `the slotted head I2 to veii'eci its adj ustmentand it isnormally secluded in the fitting 2 b y the removable screw plug I2.

The thermostatic couple comprising the rod member I extending within and shielded by the other coupling -'member I5 which is a tube, is

supported in horizontal position by connection with the snap spring casing Il which also sup- 'Ihe principal advantage of my invention is that full opening or vclosure of the valve is .lnstantaneously effected with snap action and with considerably less difference in the time for opening and closing than in said structures of the prior art. For example, in my improved structure the valve will close in slightly more than thirty seconds upon extinguishment of the gas llames oi' the pilot burner, as compared with a `five-minute time interval required by most of the prior art devices.

My invention includes the various novel features of construction, arrangement, and method of operation hereinafter more definitely specied. f

In said drawing; Fig. I is a fragmentary vertical sectional view of a gas fired water heater conveniently embodying my invention,

Fig. IIis a vertical sectional view taken on' the lines II, n in Fig. I and showing a face view of the casing in which is mounted the snap spring and needle valve for controlling the pilot burner.

Referring to Fig. I;4 the gas inlet I in the ilttlng 2 may be connected to any convenient source of gas supply, conveniently by the pipe 3. 'I'he manually operative shut-otr valve 4 controls the ilow of gas to another thermostatically operative valve, for exam'ple such as shown in Letters Patent No. 1,974,646, conveniently located in the upper portion of the water container of the heater, which functions to prevent heating the water beyond a predetermined limit for which that valve is set. The pipe 5 extends from that ports the pilot .burner tube I8 parallel therewith. Said pilot tube I8 is connected by suitable piping 4in the to the gas supply pipe, so that gas is supplied continuously to said pilot tube I8. Said pilot burner I8 has the flame jet orice I9 at its left hand end beneath said tubular member I8 of the thermostatic couple and the inner end of said tube I6 is shielded by the sleeve 20 overhanging the flame orifice I 9 of .the pilot burner. The supply of gas `to'thepilot burner may be precisely regulated and controlled vby the needle valve 2i which may be turned bythe knob 23 shown in Fig. II.

The right hand end of the rod I5 shown in" Fig. I is seated in the thrust disk 25 which bears upon the supporting plate 28 which engages the perimeter of the snap spring 2l which. when the` device is cold, is in the in Fig. I. The adjusting plunger 29 is continually concave position shown screw 28 carried by the stressed toward the rod by the spring 30 in said casing I'I but, when cold,

the valve 3i is closed.

When heat is applied by the flame oi' the pilot burner, at orifice I 9, the tube I8 expands; pressure on the rod I5 is lessened and when the temperature difference between the tube and the rod has' reached a certain will snap to the reverse position, opening the valve 3i. Gas is then permitted to pass through the shut-off valve l and back through the pipe 5, when the valve I is opened, and the pilot burner I8 will light the main burner 8 if the thermostat is calling for heat.

should the name atthe punt burner orifice n be extinguished; the tube I8 will begin to cool rst, but the rod i5 will retain whatever temperature it has reached for a longer period. hastening the closure of the safety shut-off valve 8i. 'I'here can be no critical danger point because the rod I5 remains slightly warmer than the tube I6 during the entire cooling on' period.

'Ihe sleeve 20 at the inner end of said tube I5 well known manner directlyy point the snap spring 2l shields it from thedirect pilot iiame; thereby preventing the heat from reaching the plug 32 l and transferring heat to the rod I5. Said sleeve also carries the heat directly to the main expanding portion of the tube IB.

I do not desire to limit myself to the precise details of construction, arrangement or method of operation herein set forth,v as it is obvious that various modifications may be made therein without departing from the essential features of my invention as dened in the appended claim.

I claim:

In thermostatically operative valves for heat ing means including a maingas burner; the combination of a valve controlling .the supply of gas to said main burner; aspring tending to move said valve to closed position; a pilot burner, having a flame orice, for said main burner; a thermostatic couple composed entirely of the same material in operating relation to said valve and said pilot burner; one member of said couple being a rod and the other member of said couple being a 'tube completely 'enclosing said rod; a sleeve mounted at oneend of said tubulaimember and interposed between said tubular member and the flame orice of said pilot burner; said sleeve being fastened at one end to said tube and opened at its opposite end; and a snap spring between said rod of said thermostatic couple and said valve, and in operating relation to both said valve and said rod of said thermostatic couple; whereby movement of said rod in a direction away from said valve caused by expansion of the tube of said thermostatic couple when said pilot burner is lighted will permit said snap action spring to snap to convex position to move said valve to open position; and

movement of vsaid rod in a direction toward said valve caused by contraction of the tube of said thermostatic couple when said pilot burner is extinguished will cause said snap spring to snap to concave position away from said valve and permit said valve to be -moved tov closed-position by its spring. t

ROBERT J. DOUGHERTY.

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