US2593238A

US2593238A - Thermally responsive device

Info

Publication number: US2593238A
Application number: US55797A
Authority: US
Inventors: John C Albright
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-10-21
Filing date: 1948-10-21
Publication date: 1952-04-15
Anticipated expiration: 1969-04-15

Description

April 15, 1952 J. c. ALBRIGHT THERMALLY RESPONSIVE DEVICE 2 SHEETSSHEET 1 Filed Oct. 21, 1948 mam-mnwm all!!! s v E N R 0 T T A IN V ENTOR.

H W e E v 5 W L O l W W Y O B d April 15, 1952 J. c. ALBRIGHT THERMALLY RESPONSIVE DEVICE Filed 001.. 21, 1948 2 SHEETSSHEET 2 INVENTOR.

A 7- TOR/YE Y5 I atented Apr. 15, 1952 THERMALLY RESPONSIVE DEVICE John C. Albright, Chicago, Ill., assignor of onehalf to William J. Adams, Chicago, Ill.

Application October 21,1948, Serial N 0. 55,7 97

This invention relates to a thermally responsive device.

The invention is concerned particularly with the type of thermostat in which the pressure of a substantial body of thermally expansible material is concentrated on a plunger of relatively small cross sectional area to produce a relatively large axial response of the plunger commensurate with the relatively larger mass of the body which is developing pressure. A device of this general type is disclosed in Patent 432,182 of July 15, 1890. The pressure developed by the expansible body and communicated to the plunger may be used for any desired purpose, as to open or close a switch'or valve, or to actuate any other part.

It is the purpose of the present invention to preclude leakage of the expansible material outwardly along the bearing surface of the plunger while, at the same time, avoiding the destruction which usually follows when a diaphragm is bent. The ordinary diaphragm subject to the pressure of a large mass of material on one face and en-,

gaged on its opposite face only by the plunger would obviously be required, in effecting plunger movement, to become attenuated and cupped to enter the plunger bore in propelling the plunger outwardly therein. According to the present invention, the expansible material is wholly confined by a diaphragm in which motion'is effected by deformation rather than by flexing of the diaphragm. The material of the diaphragm is soft enough so that it actually flows and the form of the chamber is such that it tapers curvilinearly at the point where the diaphragm is confined therein, thus avoiding any sharp corners across which the diaphragm may be bent or cut.

More specifically, it is an object of the present invention to provide a deformable diaphragm which is one piece with a liner for the chamber which contains the thermally responsive material, the said liner being extended over the mar gin of the chamber remote from the diaphragm portion of the liner and anchored to the chamber by a closure cap at the end thereof.

. A further important object of the present invention is the provision of a construction in which the diaphragm or deformable portion of the liner is upwardly crowned, and the change in crosssectional area of the chamber in which the diaphragm is confined is effected gradually, the liner conforming to the interior shape of the chamber and preferably, though not necessarily, remaining without material change in wall thickness until it reaches the diaphragm or deformable plug portion which caps thetopof the chamber.

18 Claims. (01. 297-43) Other objects of the invention will be more apparent from the following disclosure thereof:

In the drawings:

Fig. lis a vertical axial section through a device embodying the invention.

Fig.2 is a view in transverse cross section taken on the line 22 of Fig. 1.

Fig. 3 and Fig. 4 are fragmentary detail views showing in axial section slightly modified embodiments of the closure of the device of Fig. 1.

Fig. 5 is a side elevation showing a preferred embodiment of the invention.

Fig. 6 is a View on an enlarged scale taken in section axially through the device of Fig. 5.

Fig. '7 is a view taken in section diagrammatically illustrating the manner in which the rubber insert shown in Fig. 6 is molded directly in the chamber in which it is tooperate.

Fig. 8 is a view diagrammatically illustrating the molding into the form of a pellet of the thermostatically responsive material to be inserted.

Fig. 9 is a view showing the insertion of the pellet into the pre-molded skirt.

The container 3 has the interior form of a bottle, comprising a relatively large chamber at 4 and a gradually tapering throat at 5 leading to the cylinder portion 6 in which the power transmitting plunger 1 is reciprocable under the bias of spring 8. The sleeve shown at 9 is merely a conventional illustration of any suitable spring seat.

In the throat 5 and extending substantially to the beginning of the cylindrical portion 6 is a deformable diaphragm or plug H) which is molded to provide integrally a liner or sleeve I ll extending downwardly along the inner wall of the throat portion 5 and the chamber portion 4 of receptacle 3. The wall thickness of the skirt or liner II is substantially uniform until it merges with the diaphragm or plug II], at which the inner surface is preferably upwardly concave as indicated at 2, diverging sharply from the outer surface of the plug or diaphragm which is molded to fit and conform to the inner surface of the receptacle where the tapered throat merges with the cylinder 6.

It will be observed that the portion of the rubber body In which is adjacent plunger 1 constitutes an elastically deformable plug which, when distorted, tends to resume its shape. That portion of the body of rubber shown at II] which is nearest to the filling 20 hereinafter described constitutes a diaphragm. Its operation is distinctly different from that of a conventional diaphragm since there are no margins 3 anchored at this end of the chamber where, due to repeated flexion and tension, they would tend either to tear or pull free. Instead, the diaphragm is anchored at the remote end of the chamber, as will now be described.

At its end remote from the diaphragm or plug, the receptacle is outwardly flanged at I3. The liner II has an outwardly flanged portion I4 and is preferably provided with a peripheral channel at l5 completely enclosing the flange l3 of the receptacle. The channel is, however, non-essential, since the flange It forms an adequate seal when the closure IB is applied and anchored by spinning its flange portion I! over the flange 13 of the receptacle, with or without the intervening channel l5. The closure It must be substantially non-yielding in response to pressures developed within the receptacle, and accordingly, it is desirably reenforceol in some manner, as by convexing it upwardly at its center at l8.

The space within the liner and the closure i8 is completely filled with a body 25 of any thermally expansible material, an example being the material disclosed in U. S. Patent No. 432,182 of July 15, 1890. Other examples include beeswax alone or in different compositions, and paste mixtures of resin or wax with crystalline materials. Among many suitable formulae are the following:

60 CsI-I4CL2' (paradichlorobenzene) 6.5% raw cocoanut oil 6.5% raw castor oil 27% commercial beeswax 3 grams beta napthol .3 gram ester gum resin (No'rE.The figures given will make one pellet of thermally responsive material .375 inch in diameter and .437 inch long. Operating within a skirt of comparable dimensions to move a piston having a diameter of .156 inch, this particular material will respond at 200 F. to produce a piston travel of .048 inch against a load of 150 pounds per square inch.)

When the device is subjected to an increase in temperature, the rate of expansion of the filler 26 being greater than the rate of expansion of the receptacle 3, pressure is exerted on the receptacle and its liner in all directions.

The bottom closure [6 will not yield appreciably, but the pressure thereon will increase the binding engagement of its flange I! with the portion of liner channel which is confined against body flange [3. The only direction in which appreciable yielding can occur is in the direction in which the deformable plug or diaphragm [0 can expand into the cylinder 6, displacing the plunger 1 against the compression of spring 8. Since the relatively small lineal movement in the relatively larger cross section of chamber 4 is communicated into a cylinder of ,very much smaller cross section, the lineal movement will be multiplied and is capable of operating a switch or other part in response to the change in temperature. If the temperature is subsequently reduced, the material will shrink, and the parts will resume their original position, due not only to the compression of any spring used at 8, but due also to the tension developed in the liner H and the plug it) during the expansion. The expansion of material 2i} deforms the plug by forcing it into a throat of progressively restricted cross section from which the plug tends to escape as it elastically resumes its original form. Tension is also distributed over substantially the entire liner ll, movement of the plug into the throat causing a slight attenuation of the liner which is resisted by its inherent elasticity, the liner being desirably made of natural or synthetic rubber, or a silicone or the like.

The distribution of the stress throughout the entire liner precludes any possibility of developing excessive strain at any one point. Leakage is also precluded, since the liner itself provides the gasket between the closure and the receptacle.

The fact that the seal is effected at the remote end of the chamber is a great advantage in a small unit because the operating end thereof can be of much smaller. over-all diameter.

If desired, I may use a liner at 2| for the closure l6 as shown in Fig. 3. .The material used at 2! may, if desired, be the same as that usedto make up the liner II and plug 10. It takes the form of a disk, the margins 22 of which are included. within the flange H of closure [6 when such flange. is spun. around the flange 13 of the receptacle 3. Alternatively, the liner 23 may be of smaller diameter so that its margins, preferably skived as indicated at 24 in Fig. 4, will terminate beneath the lower marign of receptacle 3, without being carried about the flange l3 thereof. The liners 2| or 23 will ordinarily be used when it is desirable to protect the closure l5 from the expansible material 26 used within the device. However, the disks 2| and 23 may contribute to the effective seal of such material.

While I have referred to a plunger and to a cylinder portion of the receptacle, it will be observed that the cylinder and plunger are nonessential to the operation of the device, since any part engaged by the plug or diaphragm will be actuated thereby, the plunger being merely a preferred means of receiving and communicating motion.

While the forms of the invention heretofore disclosed are entirely satisfactory, I prefer the embodiment now to be described, with the details of the method used in its manufacture.

The receptacle 30 provides an interior chamber 40 which is closely comparable to that shown in Fig. 1, being provided with a throat 50 tapering to the cylinder 60 in which the power transmitting piston or plunger 10 is operable. As above indicated, no spring is required and none is here shown, the elasticity of the rubber plug I00 being relied upon to restore the thermostatic pellet 2m] to its. original form as the device is cooled after operation.

The skirt portion H0 extending along the wall of chamber 40 from plug N10 is attached to the remote end of receptacle by means of cement 3| applied as hereinafter described. The closure I takes the form of a cap having an outwardly projecting stud at l8! and an inwardly projecting boss at I82 against which the thermostatically responsive material 200 seats. The channel I83 between the boss I82 and the flange I84 compresses and conforms the reversely bent thermal portions III of the liner sleeve H0. Solder or brazing or the like is used at I85 to connect the flange I84 of the closure cap I80 to the wall of the receptacle 30. a

amazes A preferred method of manufacture is as follows:

The receptacle 30 may be made in a screw machine or otherwise to the form indicated in Figs. 6, 7 and 9, the outer periphery of its open end being cut away to form an annular groove at 32. With the plunger 10 closely fitting into the cylincler 60, the receptacle is placed in a die 34 which has a cavity at 35 to receive it. The upper end of the die is preferably flush with the open end of the receptacle.

The interior of chamber 40 of the receptacle is coated with any soap, the soap constituting a lubricant which prevents the rubber from adhering thereto. Similar lubrication may be provided for the wall and throat of the chamber 4 in the constructions previously described, although it is not as much needed in those devices. Adjacent its open end, however, the wall of the chamber 40 is coated with cement 3| which preferably extends about the open end and covers the surfaces of the groove 32. Any rubber cement is usable, but it is preferred to employ the product known commercially as a nitrate dope primer, this being a synthetic latex.

Into the chamber 40 is now dropped a small ball of a rubber which is suitable. to use a synthetic rubber of 30 denier which is made by mixing 80% by weight of hycar with 20% by weight of neoprene. For the particular device shown, in which the interior of the sleeve H is to have a diameter of .375, and a length of .437, the finished rubber plug and sleeve will include approximately one gram of rubber, but the ball 36 initially inserted will desirably contain some excess, for example, one and threetenths grams.

The receptacle 30 is preferably preheated to 300 F. before being inserted in the mold 34, which may also be heated by resistance element 340. The ball of rubber is now subjected to a pressure of 800 pounds to the square inch by means of a ram 31 as shown in Fig. 7, the shape of which determines the interior shape of plug I00 and sleeve liner H0. The ram is shouldered at 30. The excess rubber escapes as flash as indicated in dotted lines at H2. The rubber is held in the die under pressure of about 800 pounds until cured and vulcanized to the receptacle at the primed open end thereof. After the cure is completed, the rubber will stand 500 F. without deterioration.

In order to make sure that the thermo-responsive filler shown at 200 fills the lined chamber to capacity, it is preferred that the paste or other material to be used be preliminarily molded into a pellet as shown in Fig. 8. If desired, the thermally responsive material may be mixed with an inert powder to give it body. A mold 20| is provided, the mold desirably having an ejection plunger 202 with projecting rod 203. The thermally responsive material 200 is placed into the cavity of the mold and compressed by a ram 204 which desirably uses 8,000 pounds to the square inch. The resulting pellet 200 is form-sustaining and may, as shown in Fig. 9, be forced into the lining sleeve I [0. As shown in Fig. 6, in the ultimate position of the pellet 200, the boss I 82 of the closure cap I80 slightly enters and compresses the rubber at the open end of the receptacle. The device is again placed in a press and subjected to any desired degree of high pressure suflicient not only to assure the elemination of all voids, but to overcome any tendency of the pellet 200 to expand during the soldering of It is preferred the flange I84 to the external wall of the receptacle, which is now accomplished to complete the unit.

Such a device has the important advantage that its operating end is very small in diameter and may be used in closely confined quarters. It is completely sealed and has long life since, as above noted, there are no bending strains imposed on the diaphragm, its deformation being a matter of compression and its anchorage being effected through the elongated lining sleeve H0, whereby such tension as is developed. is widely distributed.

I claim:

1. In a pressure responsive device, a chamber having a side wall defining a pressure compartment and a pressure delivering throat providing a progressively narrowing wall surface leading smoothly from said side wall, together with an integral elastic diaphragm and plug in said throat having a liner extending from said diaphragm along the wall of said chamber, said diaphragm and plug being deformable to fiow out- ,Wardly and inwardly along said throat, means connected with said liner for the anchorage thereof, and a body of material having a higher coefficient of thermal expansion than the chamber and confined therein within said liner and diaphragm in all positions of deformation thereof. I

2. In a pressure responsive device, a chamber having a pressure compartment of relatively large diameter and a cylinder compartment of materially smaller diameter and a tapered throat providing a wall surface which includes the side and end of the pressure compartment and the side of the cylinder compartment, said surface gradually changing direction between said compartments, together with a diaphragm spanning the pressure compartment and having a liner extending along the wall of said pressure compartment and provided with marginal anchorage thereto as a complete closure between said cornpartments, a deformable body within said throat integral with said diaphragm and substantially filling the space between the diaphragm and said throat and adapted to fiow toward the cylinder compartment in response to increase of relative pressure in the pressure compartment and a body of material having a higher coefficient of thermal expansion than the chamber and confined therein within said liner and diaphragm and effecting the flow of said deformable body along said throat.

3. The device of claim 2 in which the anchorage is eifected by cement.

4. The device of claim 2 in which the anchorage is effected by mechanical pressure interlock, the said chamber having a closure cap and said sleeve having a flange confined between the closure cap and the chamber.

5. In a device of the character described, a bottle-shaped receptacle having a chamber for thermally expansible material and provided beyond said chamber with a gradually tapering throat and a cylindrical neck, a plunger reciprocable in said neck, an elastically deformable plug in said throat and engaging said plunger, said plug having a depending skirt extending from said plug along the interior surface of said chamber and confined between said body and said receptacle, the said receptacle and skirt being flanged outwardly at a point remote from said throat and provided with a closure for which the outward flange of the skirt provides a gasket.

has achannel-shaped portion. completely enclosing the outward flange of the receptacleand.

substantially completely embraced. in a channelled flange of the closure.

71. A device of the character described com.- prising: a receptacle having a chamber portion for thermally expansible material. opening to one end of the receptacle and a cylinder communicating'with. said chamber portion and opening at. the one end thereof, a combination plug diaphragm and lining. sleeve in the chamber portion, said sleeve extending. to the open end thereof, the receptacle at such end being provided with a groove about its perimeter at which the wall thickness of the receptacle is reduced, the lining sleeve extending over the end of the receptacle and into said groove, a thermally expansible material completely filling the lining sleeve, and a closure confining such material under pressure and in pressure engagement over the end of said receptacle with the lining sleeve portion turned thereover, and means connecting said closure with the receptacle whereby to maintain such pressure engagement.

8. The device of claim '7 in which the interior of said receptacle is lubricated to promote free movement of the sleeve, diaphragm and plug except adjacent the open end of the receptacle, the receptacle being provided interiorly adjacent its open end with cement connecting said sleeve with the receptacle solely at such end.

9. The method of making a thermostat of the character described which comprises prefabricating an open-ended thermostat receptacle having an extension comprising a throat and cylinder, closing a portion of the cylinder against communication of the receptacle therewith, introducing a body of raw rubber into the receptacle, molding such rubber as in a die under heat and pressure directly in the receptacle in position for use as a one-piece diaphragm and elastically attenuable liner for the receptacle, said diaphragm constituting a partition between the cylinder and the said receptacle.

10. The method of making a thermostat of the character described which comprises prefabricating an open-ended receptacle having a throat and cylinder, introducing a body of raw rubber into the receptacle, molding such rubber as in a die under heat and pressure directly in the receptacle to constitute a one-piece diaphragm and liner for the receptacle, said diaphragm separating the cylinder from the rest of said receptacle, vulcanizing the liner to the receptacle at a point remote from said cylinder while leaving it free of the receptacle elsewhere, pressing into the lined receptacle a preformed pellet of thermally expansible material and sealing the receptacle across the liner behind said pellet.

11. The combination with a receptacle comprising a chamber portion for thermally expansible material uniformaly converging at one end and lining the wall of said chamber portion and being free for attenuation in the movement of said plug, and the thermally expansible material being confined within. the wall of said liner.

12.. The combination With. a. receptacle comprising a chamber portion for a thermally ex-..

pansible material, a throat of reduced cross: section communicating with said chamber portion,

an elastic deformable plug in. said throat provided with a skirt-like linerconforming to the wall of. said chamber portion and constituting aiming therefor,. means anchoring; said liner to said receptacle at a point axially remote from said throat, said liner being elastic and. free for attenuation in the movement of, said. plug, and a. closure. for said receptacle having-a1 lining. constituting; a closure for said. liner, thereby completely closing the: space within said liner.

13.. In a. device of. the character described, the combination. with a receptacle comprising a chamber for a thermally expansible material,.the wall. of. said chamber uniformly converging into a throat of decreased cross" sectional. area, an elastic. deformable plug mounted within said throat, said plug having an elastic attenuable skirt-like. liner extending therefrom along the Wall of said chamber and forming a liner there.- for, the body of. the thermally expansible. material being contained within saidv skirt and entirely filling the space therein, means at the opposite end. of said. receptacle. from. said plug anchoring said skirt: to said receptacle and allowing fre'e attenuation of. said skirt intermediate said anchoring means. and plug; and closure means closing the end. of said receptacle adjacent the region of anchorageof said liner thereto.

14. The combination set. forth in claim 13; in.

tween the end of the chamber and closure and.

comprises a gasket.

15. In a receptacle, a bodyof thermally expansible material confined therein, a pressureresponsivemember contained within said receptacle and engaged at one side thereof with. said body and acted upon by said body upon expansion. thereof, an. extensible flexible liner extending from the margin of said pressure. responsive member along the wall of said receptacle and about said body of thermally expansible material, the inner end. of said" liner being closed. by said pressure-responsive member and the outer end' of said liner being open and secured to the end of said receptacle remote from said pressureresponsive member, and a closure member for the. open end of said liner and associated end of said receptacle and reacted against by said body of thermally expansible material, whereby pressure thereagainst by expansion of said body atten-tuates said sleeve and. effects the flowing of said pressure-responsive member along said receptacle.

16;. In a. receptacle. a body of thermally expansible material confined therein, a pressureresponsive member contained within. said receptacle and engaged at. one side thereof w-ith said body and acted; upon by said body upon expansion thereof, an extensible flexible liner extending from the margin of said pressure-responsive member along. the. wall of said receptacle and about said. body of thermally expansible material, the inner end of said liner being closed by said pressure-responsive member and the outer end of said liner being open and secured to the end of said receptacle remote from said pressure-responsive member, a closure member for the open end of saidliner and associated end of said receptacle and reacted against by said body of thermally expansible material, whereby pressure thereagainst by expansion of said body attentuates said sleeve and effects the flowing of said pressure-responsive member along said receptacle, and the connection between the end of said sleeve and said receptacle being a cemented connection.

17. A receptacle having a chamber portion for a thermally expansible material and having a cylindrical portion for a plunger opening therefrom, a diaphragm separating said cylindical portion from said chamber and a skirt-like liner extending therefrom and lining the wall of said chamber, the said receptacle terminating in a flange having an external shoulder, and said liner extending over said flange, and a closure member clamping against said flange and a portion of said liner extending thereabout and having a boss wedged against said liner and within said flange.

18. A receptacle comprising a chamber portion for a thermally expansible material and having a cylindrical portion for a plunger opening therefrom, a diaphragm separating said cylindrical portion from said chamber and having a skirtlike liner extending therefrom and lining the wall of said chamber, the said receptacle terminating in a flange having an external shoulder, the said liner extending over said flange, and a JOHN C. ALBRIGHT.

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

UNITED STATES PATENTS 15 Number Name Date 1,399,780 MacDonald Dec. 13, 1921 1,475,463 Weida Nov. 27, 1923 1,850,683 Merrill Mar. 22, 1932 2,259,846 Vernet Oct. 21, 1941 2 2,310,519 Eskin Feb. 9, 1943 2,368,181 Vernet Jan. 30, 1945 2,456,615 Berglund Dec. 21, 1948 FOREIGN PATENTS Number Country Date 345,050 France Sept. 28, 1904 531,280 Great Britain Jan. 1, 1941 702,868 France Jan. 27, 1931