US2598351A - Thermostatic valve - Google Patents

Description

y 1952 F. Y. CARTER 2,598,351

THERMOSTATIC VALVE Filed April so, 1948 I80 I90 200 2|O 220 TEMP F INVENTOR. FIG.3 3W

ATTORNEY Patented May 27, 1952 THERBIOSTATIC VALVE Franklyn Y. Carter, Dearborn, Mich., assignor to Detroit Lubricator Company, Detroit, Mich a corporation of Michigan Application April 30, 1948, Serial No. 24,189

7 Claims.

This invention relates to new and useful improvements in thermostatic valves and more particularly to valves for relieving dangerously high pressures resulting from high temperatures in fluid containers such as receivers. in refrigeration systems or for draining excess hot water from a domestic hot water tank.

One of the objects of this invention is to provide a new and improved thermostatically operated valve.

Another object is to provide a thermostatically operated safety valve which will open very slowly until a predetermined temperature is reached and then will open rapidly upon rise in temperature within a predetermined range and will close rapidly upon fall of temperature within said range.

Another object. is to provide an improved valve for relieving excessive pressure in a refrigerant receiver resulting from excessive temperature.

Another object is to provide an improved valve for automatically draining water from a domestic not water tank upon excessive rise in temperature therein...

Another object is to provide a thermostatically operated mechanism which will not have operative movement until a predetermined temperature is reached and then will move through its entire range of operative movement rapidly and with n. asmall predetermined range of temperature.

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

This invention comprises the. new and improved construction and combination of parts, to 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 a part of this. ecificat the e r c rl a d ful y llustr ted two Pref rr d m odime s of this invention, in which drawings:

Figure. 1 is a view in vertical'cross-section of a valve, embodying. this invention and particularly adapted for relief of excessive pressure in a refrigerant receiver,

g. 2 is a view v tical. crosst on of a valve em o y ng t is i vention and. p rticular y dapted. for draining. excess. hot. water from a domestic water. heating tank. and

Fig... is a. graph illustrating. the change. in, ex p n n f th t rmouesponsi cmat ri l. used in. the power-element with change oi temperature.

Referring to the drawings by. characters of reference, there is shown in Fig. 1 a segment of a casing l of a liquid refrigerant receiver and having an internally screw-threaded fitting 2 thereon. Screw-threadedly secured in the fitting 2 there is a plus member 3 v n a n r l passageway 4 extending longitudinally therethrough and having an internal partition 5 dividing the passageway 4 into two sections 6 and I. There is an aperture 3 in the partition 5 which provides a valve port. A valve member 9 which is positioned externallyof the port 8 is cooperable therewith to control fluid f ow through the passageway 4 The valve member 9 is carried by a valve stem I!) which extends through the valve port 8 into the passageway portion 1 and is adjustably screwthreade dly secured in an actuating piston H. There is a power element structure I2 comprising a tubular guide member having a cup-shaped member l3 screw-threadedly secured in the passageway portion 1 and having a hollow cylindrical projecting portion l4 extending from the base thereof. There are provided in the base of the cup-shaped member l3 one or more apertures 15 which permit fluid flow to the valve port 8. The cylindrical projecting portion M has an annular flange l6 around its end portion and is provided with a passageway or bore extending longitudinally therethrough. There is a cup-shaped power element I! which is secured the piston .120".

' to. the flange it by an inturned flange portion [8 and which closes the bore of the projecting portion Hi. There is a flexible resilient diaphragm I9. which extends across the open end of the power element l1 and which is secured at its edge portion between the power element l7 and the flange portion l8. Enclosed between the power element H and the diaphragm [9 there is a th'ermo-expansive material 20 which has a low rate of expansion at temperaturesboth below and above a. predetermined temperature range and has a. high rate of expansion within the predetermined temperature range. This material is preferably a wax or mixture of. waxes (or other organic solids); having a high rate of expansion when passing througha change of; state and containing a high percentage (around 75-8Q% of a finely divided heat transfer material such as powdered copper held in suspension. by a viscous binder material such as polyisobutylene (Vistanex). The use of thermostatic material of this t pe is taught in Patent 2259 846, to Vernet.

If reference be had to Fig.3,'it is seen that in the 10 range of temperature from 205 F. to 215. B. there is an expansion sufiicient to move The rate of expansion with temperature may be varied according to the composition of material used in the power element and such compositions are disclosed and taught in the aforementioned patent to Vernet. The piston l I which is adjustably secured to the valve stem 10 is slidably positioned in the bore of the projecting portion Hi. There is provided within the bore of the projecting member 14 and abutting the diaphragm IS a compressible and elastic plug member 2! which is operable to transmit movement from the diaphragm l9. Also within the bore of the member 14 there is an operating piston 22 having a projection 23 extending toward and normally having a clearance from the piston H. The pistons II and 22 together comprise a plunger or thrust member. There is a helical lost-motion spring 24 which surrounds the projection 23 and which is compressed between the pistons H and 22. The piston H has a flange 25 about its outer end portion and there is provided a spring 26 which is compressibly positioned between the flange 25 and the partition 5.

In operation this valve functions as follows: The spring 26 normally urges the valve memher 9 toward closed position and is of suficient The clearance between the piston projection 23 and the piston ll corresponds to the amount of expansion of the material 20 at lower temperatures. This motion of the piston 22 is taken up by the lost-motion spring 24 so that there is no movement of the piston H until the temperature is reached at which the material 2%) begins to go through its change of state. When a predetermined temperature is reached, for example, at the point which the thermo-expansive material 20 begins to go through a change of state the piston projection 23 has engaged the piston I l and the increased rate of expansion will cause the pistons I l and 22 to be moved rapidly within a small range of temperature thus moving the valve to a full open position to permit escape of hot gases from the refrigerant receiver l. Correspondingly, when the power element I1 is cooled the material 28 will begin to solidify and shrink in volume. As the material 20 shrinks in volume, the spring 25 will move the pistons H and 22 inward thus closing the valve 9 against its port. When the valve 8 is closed, further inward movement of the piston l l is prevented but the lostmotion spring 24 will cause the piston 22 and plug member 2! to be moved further inward with further shrinkage of the material 29 upon cooling and solidification so that voids will not be formed in the solidified material 29. To accomplish the foregoing described operation the spring 24 must be sufificiently strong to compress the thermostatic material 28 back into the power element l1 upon cooling but must be weaker than the spring 26 so that the piston 22 may have its initial movement without moving the valve 9 away from its seat.

One of the principal advantages of a valve of this type is that the valve will not begin to open until a certain predetermined temperature is reached and the valve will then open rapidly to full open position within a small range of temperature. correspondingly, the valve will close rapidly upon fall of temperature within a narrow temperature range thus preventing loss of fluid through the valve by bleeding as in conventional thermostatically operated valves when they begin to open.

In Fig. 2 there is shown a valve similar to that described which is adapted for use in automatically draining hot water tanks upon excessive rise in temperature. In domestic hot water heaters which are provided with a heating coil within the furnace, there is no means to control the amount of hot water produced with the result that in very cold weather when the furnace is operated to produce large quantities of heat, there will be produced an excess of hot water which may reach a dangerous condition. To remedy this situation it is customary in cold weather to draw oii quantities of hot water to prevent overheating of the domestic water supply.

The valve shown in Fig. 2 is provided to automatically drain water from a domestic hot water tank upon excessive 'rise of temperature. The parts in Fig. 2 which are common to those in Fig. 1 are given similar reference characters. There is shown in Fig. 2 a fragmentary section of a hot water tank 21 which has a screw-' threaded fitting 2 thereon in which is screwthreadedly secured a plug member 3. The plug member 3 has a large bore 28 at one end and has a bore 29 extending longitudinally through the body portion thereof. There is a tubular guide member having a cup-shaped member 13 which is screw-threadedly secured in the bore 28 of the plug member 3 and which has a cylindrical projecting portion [4 extending from the base portion thereof. The projecting portion M has a passageway or bore extending longitudinally therethrough and provides a valve port 29 opening into the cup-shaped portion 13. There are provided one or more apertures 32 in the wall of the cylindrical projecting portion [4 to permit flow of liquid to the valve port 29 There is a valve member 3! which has a valve stem 32 extending into the bore of the cylindrical projecting portion l4 and adjustably screwthreadedly secured in an actuating piston 33. The pistons 33 and 22 comprise a plunger or thrust member similar to the arrangement shown in Fig. l. The valve member 3! is cooperable With the valve port 29 and operable to control flow of liquid through the valve port 29 The valve member 3! has a cylindrical projecting portion or flange 34 extending longitudinally therefrom providing a cup-shaped portion. There is provided a spring 23 which seats at one end against the end wall 35 of the large bore 28 and at its other end within the cylindrical flange portion 34 of the valve member 28 and which is operable-to urge the valve member 3! toward closed position. The power element and thermoexpansive material is substantially identical in structure to that shown in Fig. 1.

The operation of this valve is substantially identical'to that for Fig. 1. The essential advantages of this valve as previously described are that the valve will not begin to open until a predetermined temperature is reached and then it will openrapidly to full open position within a very small predeterminedrange of temperature.

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

1. A thermostatic valve comprising a plug closure member for a threaded aperture and havenlarged internally. threaded portion, said closure member having an externally screw-threaded portion, a tubularguide member extending from. saidclosure member concentric with said threaded portions, said guide member having anenlarged end portion threadedly secured in said threaded passageway portion and forming there.- with a chamber andhaving apertures for flow through said passageway, valve means having a piston reciprocally guided in said guide member and'having a valve member, a valve seat having a valve port open to said passageway and reeeixn ing said valve member-for controlling flow therethrough, a coil spring in said chamber and heldunderco npression against said valve means to urge said valve member against said seat, a thermostatic power element carried by said uide member and containing a thermostatic material having a low rate of; expansion both below and above t p determine temp a u ange, a ee nd mot on. transmittin vi n r nge o be o o ei b aid ower el me nd be si m. an eo el eeble. w h e s s -n m p ston oon rede m ne e a si a heroiostat o mat rial. and a eeo nd p ing e b e w th aid. seeond. ston. e o ra l t e rn h some to. ni a osi n eoeoe m i re named. ist n up n o i oiion. Q saidv rm static. mate al- 2. A rmoe at o. va e comprising a. blue member av n p ssa ewa he e ro eb. an h vi a po ti n ilo ine a al o t a val e member. cooperable with said valve port and operable to control flow through said passageway,

a valve m. or sai va ve m m er a t ermostatic p wer e ement hav n a. movab e piston sp c o s id al e stem nd. eneee eble therewithv pon predete ned se in te no atu e to move'said valve m mber t ward. o en p i i e power elemen a n n a b rio9= responsive material having a low rate of expan- Sion both. el w and above. ermine iein: n r range ndear n t h te o i e pansion within said pr range, a st rin t r o eo etw n s piston and said valve step}, a. second spring positioned hin. said og. me b and o berab e h s alve, member nd operable o. resi movement of said valve member toward open position, said first r g being compressible to the t ntoi'eifie eeio ii m eooo material at temper pres below said predeter mined range to permit engagement of said piston and said valve s'tem, said sec ondspring being oi? sufiicient strength to prevent said valve member from being movedtoward open position by said power element priortoengagement of said piston and said valve stem, and said first spring being of sufficient strength to return said piston to its initial position spaoed; from said valve stem upon .te n n d. mp ratur contraction of said thermo-responsive material.

in its. base. for pas a e. o fluid to said. va ve port.

nd havin a ho low evlindrioal: projection. xtending from the-central p rtion. ofits ba e. aid projection. having an. annular flan e at; its en portion. a oubsshaped power element secured; to said' fl e and closing the hol ow penin rom said: projection, a flexible diaphra m. extendin across said: powerelement. and secured etwe n said power element. and said flan e, a thermoresponsive material nclo ed by sai power element. and said diaphra m. sa d; h mQ-responr sive mat r al havi a low rate expansion both below and above a prede erm ned tempe atu e rang andhavine a. high rate o expans n with n said. temperature. ran a. ompres le las c b e positioned within said; hollow projectio v and abutting s id. diaphra m, lost motion mea s DQ tioned. within said proieot on. and a utt n said elastic. plus, a. piston n. said hollow pr ject n abutting said lesbmotmn mea s and ndin into. thepassageway orti n s d by said cuphabed member. said p ston av n a ann lar flangearound its. endgrorti n and having a entral passage in. which. is seoured said valve stem, a helical sprin posit nedetwe n i p s o flan e and Sai 198 .1: .tion and operable to urge said valve toward losed position, and said spring and said: lostrmotion means. bein op ra l to revent. sa d valve from. bein ope ed: by d powerelement at temperatures. below said predetermined temperature ran e- 4. A thermostatic, valve compris a plu member externally screw-threaded at one end portion for insertion in. the wall of a fluid onaine a plug member'having a lar e bore a the other end portion thereof and having a small bore extending longitudinally therethrough, a. up-s aped member having its open end por i n screwethreadedly secured in said large bore and having a cylindrical project on extending fr m its base, a cylindrical pass geway extending from said cupeshaped memberthro h Said d iem pr je tion and formin a valve port at said cupshapedinember, at least one aperture in the wall of said cylindrieal; projection for passage of fluid tosai valveporb a valve mem er positioned e nallv of sa dro zt and a in a lve t m exten in in o. said pa ag way; sa d valv m m her having a. ho ow cylindrica fl n p n xending; l n i udinall tbereirom. a sp i n tionedi a ainst said va ve mem er w t n sa d ylinor oa flange: portion. nd a a n t aid pl s member at the end wall of Sa d l r e bor sai sp in b in opera le. to ur e said. v l member towardolo ed posi on. a pi ton l d bly n s neo n sa d: p eseeeway and. orewhread o iy ecured to. said: valve. stem). sa d c in a br J'eo on avingan annularfian e. aro n its nd portion. a hollowcup-shaped power element having a dense portion seouringitto said projection flange. and closing said; passa eway, a fl xi l d aphragm. olosine the open. end of a d pow element. and secured at. its. edge portion between said power elementond sa d; Pr j ction flan e, a merino-responsive mater N l enclosed. by said power element and. said diaphra m, said material having a low rate of. expansion both. below and above a predetermin d temperat range and having a hieo rate o expansion. w t sa d. temperature. ran e, an; elas ic. mpr ssibl pl member pos ti ned in said: passa ew y tw n a d d phra m; nd ai p ston. com ssible lost-motion. means po itioned in s id pa eway between said b ue. mem r and said. piston and compressible to the exte vt. of: expansion. of sa d thermo-responsive material at temperatures below said predetermined range, and said spring and said lost-motion means being operable to prevent opening movement of said valve member by temperature response of said power element at temperatures below said predetermined range.

5. A thermostatic actuating device comprising a tubular member, a cup-shaped power element casing closing one end of said tubular member, a thermostatic material within said casing, said material having a high rate of expansion within a predetermined temperature range, a flexible diaphragm separating said casing from the bore of said tubular member and movable in response to the expansion of said thermostatic material, an elastic plug member positioned in the bore of said tubular member and movable by said diaphragm, an actuating piston slidably positioned in the bore of said tubular member and operable to be moved by said plug member, an operating piston engaging said plug member and spaced a predetermined distance from said actuating piston, a lost-motion spring positioned between said pistons and operable to permit lost-motion between said pistons at temperatures below said predetermined temperature range, said operating piston being operable upon movement by said plug member first to compress said 10st motion spring and second to engage and move said actuating piston, a second spring engaging said actuating piston and restraining movement of the same during the lost motion movement of said operating piston, and said lost motion spring being operable to move said operating piston to its initial position spaced from said actuating 3 piston upon contraction of said thermostatic material.

6. A thermostatic valve comprising a plug member externally screw-threaded at one end for insertion in the wall of a fluid container, a passageway extending longitudinally through said plug member, a partition in said passageway and having an aperture forming a valve port, a valve positioned on the outer side of said partition and cooperable with said valve port to control flow therethrough, a valve stem secured to said valve and extending through said valve port, a cup-shaped member screw-threadedly secured in said passageway inward from said partition, said cup-shaped member having at least one aperture in its base for passage of fluid to said valve port and having a hollow cylindrical projection extending from the central portion, of its base, said projection having an annular flange at its end portion, a cup-shaped power element secured to said flange and closing the hollow opening from said projection, a flexible diaphragm extending across said power element and secured between said power element and said flange, a thermoresponsive material enclosed by said power element and said diaphragm, said thermo-responsive material having a low rate of expansion both below and above a predetermined temperature range and having a high rate of expansion within said temperature range, a compressible elastic plug positioned within said hollow projection and abutting said diaphragm, a first piston positioned within said projection and abutting said elastic plug, a second piston in said hollow projection and extending into the passageway portion closed by said cup-shaped member, said pistons being normally separated by a distance equal to the amount of expansion of said thermostatic material at temperatures below said predetermined temperature range, a lost-motion spring compressively positioned between said pistons, said second piston having an annular flange around its end portion and having a central passage in which is secured said valve stem, a helical spring positioned between said piston flange and said par tition and operable to urge said valve toward closed position, and said springs being operable to prevent said valve from being opened by said power element at temperatures below said predetermined temperature range.

'7. A thermostatic valve comprising a plug member externally screw-threaded at one end portion for insertion in the wall of a fluid container, said plug member having a large bore at the other end portion thereof and having a small bore extending longitudinally therethrough, a cup-shaped member having its open end portion screw-threadedly secured in said large bore and having a cylindrical projection extending from its base, a cylindrical passageway extending from said cup-shaped member through said cylindrical projection and forming a valve port at said cupshaped member, at least one aperture in the wall of said cylindrical projection for passage of fluid to said valve port, a valve member positioned externally of said port and having a valve stem extending into said passageway, said valve member having a hollow cylindrical flange portion extending longitudinally therefrom, a spring positioned against said valve member within said cylindrical flange portion and against said plug member at the end wall of said large bore, said spring being operable to urge said valve member toward closed position, a piston slidably positioned in said passageway and screw-threadedly secured to said valve stem, said cylindrical projection having an annular flange around its end portion, a hollow cup-shaped power element having a flange portion securing it to said projection flange and closing said passageway, a flexible diaphragm closing the open end of said power element and secured at its edge portion between said power element and said projection flange, a thermo-responsive material enclosed by said power element and said diaphragm, said material having a low rate of expansion both below and above a predetermined temperature range and having a high rate of expansion within said temperature range, an elastic compressible plug member positioned in said passageway between said diaphragm and said piston, a second piston in said passageway and abutting said plug member, said second piston having a projection extending toward and spaced from said first-named piston, a lost-motion spring compressively positioned between said pistons, and said springs being operable to prevent opening movement of said valve member by temperature response of said power element at temperatures below said predetermined range.

FRANICLYN Y. CARTER.

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

UNITED STATES PATENTS Number Name Date 853,503 Eddy May 14, 1907 1,099,568 Neville June 9, 1914 1,491,189 Birtch Apr. 22, 1924 1,920,505 Henney et al. Aug. 1, 1933 2,031,558 Clifford Feb. 18, 1936 2,439,336 Dillman Apr. 6, 1946

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