US3537678A - Thermal motor actuated valves - Google Patents

Description

N v. 3, 1970 1 K. SHMUELI ETAL 3,537,618

THERMAL MOTOR ACTUATED VALVES Filed Aug. 19, 1968 -2 Sheets-Sheet 2 v nvvn: 'rmcs gum/v h (/50 oaserl' corr United States Patent O1 fice 3,537,678 Patented Nov. 3, 1970 3,537,678 THERMAL MOTOR ACTUATED VALVES Kalman Shmueli, Upper Montclair, and Robert T. Scott,

Boonton Township, Morris County, N.J., assignors to International Controls Corp., Fairfield, N.J., a corporation of Florida Filed Aug. 19, 1968, Ser. No. 753,359 Int. Cl. F03g 7/06; F16k 31/02 US. Cl. 251-11 7 Claims ABSTRACT OF THE DISCLOSURE Valves are actuated by thermal motors. The valve assembly includes a valve housing which carries a thermal motor means. The thermal motor means includes an outer cylinder member and a piston member axially slidable through the outer cylinder member. The piston member has elongated portions of diiferent diameters respectively extending fluid-tightly through end walls of the cylinder member and defining between themselves in the interior of this cylinder member an annular working surface to be acted upon by the pressure of an expandable material within the cylinder member, the expandable ma terial expanding when heated. The valve housing carries an annular valve seat defining an opening through which the fluid flows when the valve assembly is open, and a valve closure coacts with the valve seat to engage the latter for closing the valve assembly and for opening the valve assembly when displaced from the valve seat. One of the above members of the thermal motor means coacts with the valve closure for displacing the latter from the valve seat when the temperature of the material within the thermal motor means increases.

BACKGROUND OF THE INVENTION The present invention relates to valves.

In particular, the present invention relates to valves which are actuated by thermal motors. The type of thermal motors herein employed constitute the subject matter of our copending application Ser. No. 702,920 filed on Feb. 5, 1968.

While it is in general known to actuate valves with thermal motors, the known structures suffer from several drawbacks. Thus, the thermal motors do not operate in a precise manner and are incapable of providing an adequate opening of a valve in response to a relatively small increase in the temperature of the expandable medium within the thermal motor. The piston and cylindner of conventional thermal motors used in such assemblies tend to wobble one with respect to the other so that a precise axial movement of structure which displaces a valve closure from its closed to its open position cannot be achieved with the known structures. Also, it is essential with the known structures to provide the thermal motors with cooling fins and the like at their exteriors, so that undesirable complications are involved in mounting such thermal motors in the valve assemblies in such a way that the thermal motors themselves will be adequately cooled.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a valve assembly which will avoid the above drawbacks.

In particular it is an object of the present invention to provide a valve assembly with a construction where the structure which actuates the valve closure moves in a very precise manner free of any possible wobble or the like.

Also, it is an object of the invention to provide for a valve assembly of a type of construction which makes it possible to achieve an adequate opening of the valve assembly in response to a relatively small increase in the temperature of the expandable medium of the thermal motor.

Also, it is an object of the present invention to provide a construction where no cooling fins or the like are required for the thermal motor, so that an exceedingly simple structure can accommodate the thermal motor in the valve assembly of the invention.

In addition, it is an object of the present invention to provide a thermal motor structure which can be used interchangeably with diiferent types of valves, so that only one type of thermal motor construction will suffice for a number of different types of valves.

In accordance with the invention, the valve assembly has a housing within which the thermal motor means is located, this thermal motor means including a cylinder member and a piston member axially slidable one with respect to the other. The piston member has elongated portions of different diameters respectively extending fluidtightly through end walls of the cylinder member, and within the latter there is an expandable medium which responds to an increase in temperature in order to displace one of these members with respect to the other. A heating means also forms part of the thermal motor means for heating the medium therein so as to displace one of the members of the motor with respect to the other. The housing of the valve assembly is provided with an annular valve seat through which the fiuid flows when the valve assembly is in an open position, and a valve closure is moveable toward and away from the valve seat to engage the latter for closing the valve assembly and to open the valve assembly when the valve closure is displaced from the valve seat. One of the above members of the thermal motor means coacts with the valve closure for displacing the latter from its closed to its open position when the temperature of the expandable medium within the cylinder member increases, so that in this way opening and closing the valve assembly is controlled according to the temperature of the expandable medium within the cylinder member. Because the piston member is guided at both of the end walls of the cylinder member a very precise control of the valve assembly is achieved, and in addition the formation of an annular working surface within the cylinder member where the piston member portions of ditferent diameters intersect each other provides a relatively large displacement for the valve closure in response to a relatively small increase in the temperature of the expandable medium.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated, by way of example, in the accompanying drawings which form part of this application and in which:

FIG. 1 is a schematic illustration of the thermal motor means;

FIG. 2 is a sectional elevation of one embodiment of the valve assembly of the invention;

FIG. 3 is a sectional elevation of another embodiment of a valve assembly of the invention;

FIG. 4 is a plan view taken along line 44 of FIG. 3 in the direction of the arrows;

FIG. 5 is a sectional elevation of a third embodiment of a valve assembly of the invention; and

FIG. 6 is a sectional elevation of another embodiment of a valve assembly of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown therein a thermal motor means 10 of the invention which is capable of being used in all of the dilferent valve assemblies described below. This thermal motor means includes an outer cylinder member 12 and a piston member 14 one of which is axially slidable with respect to the other. This piston member 14 has elongated portions 16 and 18 of different diameters extending fluid-tightly through opposed end walls of this cylinder member 12, as schematically indicated in FIG. 1, and these different diameter portions 16 and 18 intersect at an annular shoulder 20 which forms a working surface within the hollow interior of the cylinder member 12. This hollow interior of cylinder member 12 is filled with an expandable medium, such as a suitable wax well known in the art and having the property of expanding when it increases in temperature. The wax may be a natural wax or a synthetic wax. Moreover, the ex pandable medium may be any thermally expansive material for which there is a reversible cycle of expansion and contraction.

In order to increase the temperature of the wax, a heating means 22 is situated within the cylinder member 12, as schematically shown in FIG. 1. The particular heating means 22 illustrated herein by way of example is energized by means of leads 24 which extend fluid-tightly through an end wall of the cylinder member 12 to the exterior thereof where the leads 24 are connected into a circuit Which includes a source of power 26 and a thermostat, timer or other suitable control T which closes the circuit automatically, as when a certain temperature is reached or when a certain time is reached. In response to closing of this circuit the heating means 22 will be energized so as to expand the medium within the cylinder member 12, and the pressure medium acts on the working surface 20 so as to displace the cylinder member 12 and the piston member 14 axially one with respect to the other. It is to be understood that any other heating means may be employed, such as one in the form of means circulating a heated fluid or induction heating means. Because the working surface 20 is formed by the annular shoulder between the pair of portions 16 and 18 of different diameters, a relatively small increase in the temperature within the cylinder member will result in a relatively large axial displacement. Because the piston member 14 is guided by both of the opposed end walls of the cylinder member 12, a very precise, wobble-free guiding of the displaceable member of the thermal motor means is achieved.

Referring to FIG. 2, the valve assembly 30 illustrated therein includes the valve housing 32 which is provided in its interior with a valve seat 34. A valve closure 36 is urged toward the valve seat by a spring 38 so as to tend to maintain the valve assembly 30 in its closed position.

A ring 40 is fixed to the top of the housing 32, by way of bolts 42, and a suitable sealing ring 44 is situated between the housing and the ring 40. Within the ring 40 is an elongated tubular sleeve 46 which is threaded into ring 40, as shown in FIG. 2, and which also has a sealed engagement with the sealing ring 44. This sleeve 46 accommodates the cylinder member 12 in its interior, while the larger diameter portion 16 of the piston member 14 is directed toward and situated adjacent to valve closure 36. Adjacent its top end the cylinder member 12 is formed with a groove which receives a sealing ring 48 which engages the inner surface of the sleeve 46. The top threaded end of the sleeve 46 has a cap 50 mounted thereon, and this cap 50 threadedly carries a tubular member 52 through which the leads 24 extend.

Thus, with this construction when the expandable medium within the cylinder member 12 has its temperature increased by energizing of the heating means 22, the piston 14 will be displaced downwardly to engage the closure 36 and displace it in opposition to the spring 38 to its open position opening the valve so that the fluid can flow therethrough from the inlet chamber 54 to the outlet chamber 56, these chambers being connected to any suitable inlet and outlet conduits. The entire ring 50 can be turned so as to adjust the angular position of the sleeve 46, and this sleeve 46 carries at its right lower end, as viewed in 4 FIG. 2, a throttling control 58, so that by adjusting the angular position of the sleeve 46 the position of the throttling control 58 can be regulated at the downstream side of the valve seat 34.

In addition, the tubular member 52 can be threaded to a greater or lesser extent along the axis of the cylinder 12 so as to control the distance through which the piston 14 moves to displace the closure member 36, and in this way the stroke of the thermal motor means which controls the valve assembly can be regulated. Of course, the pressure of the expanding fluid within the cylinder member 12 urges the cylinder member 12 upwardly while urging the piston member 14 downwardly, but since the upward movement of the cylinder member 12 is blocked by the tubular member 52, only the piston member will be displaced to open the valve. When the temperature of the medium within the cylinder member 12 drops the spring 38 expands to close the valve and return the piston member 14 to its starting position.

While the structure of the invention is shown in FIG. 2 in connection with a valve where the fluid flows through the valve without changing its direction, the embodiment of the invention which is shown in FIGS. 3 and 4 provides a valve assembly where the fluid changes its direction of flow by 90. The valve assembly 60 of FIG. 3 includes a valve housing 62 having a lower inlet 64 and an upper outlet 66, and the valve housing carries a valve seat assembly 68 described in greater detail below. With this embodiment the valve housing has a tubular enclosure 70 threaded into the top end thereof with a suitable sealing ring 72 situated between a flange of the tubular member 70 and the housing 62. The top end of the assembly 70 is provided with an opening for the leads 24 and it also has a vent opening which can be closed by a plug 74. The interior of the tubular enclosure 70 receives the top end of the cylinder member 12 which in this case also is formed near its top end with an annular groove accommodating the sealing ring 76 which engages the inner surface of the tubular enclosure 70. A spring 78 is situated within the enclosure 70 and urges the cylinder member 12 downwardly. The bottom end of the cylinder member 12 itself forms the closure member of this valve assembly, and for this purpose the bottom end may be provided with an outwardly directed flange or may fixedly carry an additional valve-closing plate 80 which forms the valve closure, the plate or flange 80 fixedly carrying a sealing ring 88.

As may be seen from FIG. 4, as well as FIG. 3, the valve seat assembly 68 includes a cylindrical member 82 having at its top end an outwardly directed flange 84 fixedly carrying a sealing ring 86 at its lower surface and engaging the sealing ring '88 at its upper surface. The cylindrical member 82 is open at both of its ends and at its lower end it fixedly carries a transverse supporting bar 90 formed with a central opening 17 which receives a projection 93 at the bottom end of the larger diameter portion 16 of the piston member 14. The cylinder member 82 is formed with a pair of large diametrically opposed notches 92 as illustrated or other suitable openings for the passage of fluid.

Thus, with this construction when the temperature of the medium within the cylinder member 12 increases, the force will act to displace the cylinder member 12 upwardly, in opposition to the spring 78, with respect to the piston member 14 which remains stationary at its connection with the valve assembly 68, so that in this way the closure 80 will be displaced away from the valve seat to open the valve, and of course, when the temperature of the medium within the cylinder member 12 decreases, the spring 78 will expand to return the valve to its closed position. The piston member 14 is provided with an axial bore 14a extending entirely therethrough. The bore 14a serves as pressure balancing means. Specifically, a quantity of the fluid being controlled by the valve flows through the bore in the direction away from the valve seat as the valve is closed and in the direction toward the valve seat as the valve is opened. It is also noted that the bore 14a may be employed as a conduit for heating or cooling fluid.

The embodiment of the invention which is shown in FIG. shows a thermal motor means similar to that of FIG. 3 forming part of a valve assembly where the fluid flows through the assembly without changing its direction, as was the case with the embodiment of FIG. 2. The valve seat assembly fiS' is the same as that of FIGS. 3 and 4, the flange 84' engaging the sealing ring 88 carried by the flange or plate 80'. For pressure balancing purposes in conjunction with the axial bore 14a through the piston 14, an adapter 110, provided with an annular groove retaining a sealing ring 111, is fitted onto the cylinder member 12, the sealing ring 111 thus providing a sliding seal as was provided by the sealing ring 76 and the sealing ring 76 now providing a static seal. It is thus apparent that with this embodiment when the expandable medium in the cylinder member 12 expands the cylinder member 12 will. be displaced upwardly, in opposition to the spring 78, away from the valve seat flange 84' to open the valve and the fluid will now flow through the valve from the inlet 94 to the outlet 96 of the valve assembly.

FIG. 5 further illustrates how the tubular enclosure 70 of this embodiment can be provided with a depending throttle control member 98, and for this purpose the enclosure 70' is threadedly carried by the ring 40 which is fixed to valve housing 100 by the bolts 42, as described above in connection with FIG. 2. It thus becomes possible to adjust the angular position of the throttle control 98 which in this case is also situated on the downstream side of the valve seat assembly.

In FIG. 6, in a valve housing 62 having a lower inlet 64 and an upper outlet 66, as in FIG. 3, there is provided another valve assembly according to the invention. The bottom end of the cylinder member 12 itself forms the closure member of the valve assembly and for this purpose the bottom end is formed with an annular shoulder accommodating a sealing ring 110. The valve housing 62 is provided with a tubular enclosure 170 threaded into the top end thereof with a sealing ring 72 situated between the enclosure 170 and the housing 62. The top end of the enclosure 170 is sealed by means of a plug 171 which is supported by an annular shoulder 172 on the internal wall of the enclosure 17 0. To retain the plug 171 firmly in place, the upper edge 173 of the enclosure 170 is bent over against the plug 171. To further render the construction fluid-tight, an annular groove is provided in the plug 171 in which groove is retained a sealing ring 174. An opening through the plug 171 is provided for passage therethrough of leads 24. Elongated portion 18 of the piston is retained in a bore 175 in the plug 171 and restrained against significant axial movement by a bushing 176 fixed on the elongated portion 18 and a snap ring 177 retained in an annular groove in the bore 175. A spring 78 is situated within the enclosure 170, the upper end of the spring 78 being biased against the plug 171 and the lower end of the spring 78 urging the cylinder member 12 downwardly.

With this construction when the temperature of the medium within the cylinder member 12 increases, the force acts to displace the cylinder member 12 upwardly, 1n opposition to the spring 78 whereby the valve s opened. Conversely, when the temperature of the medium wlthin the cylinder member 12 decreases, the sprmg 78 expands to return the cylinder member 12 to the position closing the valve. As in the other embodiments, the piston member 14 is provided with an axial bore 14a extending entlrely therethrough for pressure balancing.

A key 180 fixed in the enclosure 170 and WhlCh engages a longitudinal slot provided in the cylinder 12 prevents rotation of the cylinder 12; like provision can be made m other embodiments employing axial movement of the cylinder.

It is apparent, therefore, that in all of the embodiments of the invention it is possible to use substantially the same thermal motor means which can be arranged either so that the piston member thereof actuates the valve closure or so that the cylinder member thereof actuates the valve closure and indeed can have an end forming the valve closure itself. 'In addition it is clear that the assembly of the invention can use the same thermal motor means with Widely different types of valves and that a throttle control can be incorporated at the downstream side of the valve seat.

It is particularly to be noted that the cylinder member 12 has an outer smooth cylindrical surface which need not be provided with any cooling fins or the like because the desired stroke is achieved with a relatively small increase in temperature of the expandable medium with this construction, so that the structure of the invention is not unnecessarily complicated by the requirements of cooling the thermal motor means. While there is no necessity for fins on the cylinder member 12, if for a particular application the desirability of a greater cooling rate or other engineering considerations would dictate in favor of the use of fins, they could, of course, be employed. Moreover, the piston member 14 may also or alternatively be provided with fins for improving heat transfer.

It is also noted that the upper end of the piston member 14 may be operatively connected to an electrical slide wire or other suitable electrical or mechanical position sensing means and this sensing can be utilized for servo control of the valve.

In view of the features herein described, it should be appreciated that conventional valves may be readily converted to embody the present invention by removal of the conventional actuation means and incorporation of thermal motor actuation means of the type herein described.

This invention has been described in detail by refer ence to certain specific embodiments only for illustrative purposes and accordingly, it is intended that the scope of the invention, as defined by the appended claims, encompass not only that which is explicitly disclosed herein but also all obvious modifications and variations thereof.

What is claimed is:

1. In a valve assembly of the type including a thermal motor having a cylindrical member enclosing a thermally expandable material, and a piston extending axially from one end of said cylinder whereby the relative displacement of said cylindrical member and piston is a function of the temperature of said material; the improvement wherein said assembly further comprises a valve body having an inlet, an outlet, and a fiuid passage means including a valve seat between said inlet and outlet, and wherein said valve body further comprises an inner cylinder axially aligned with said valve seat, said cylindrical member being slidably positioned within said cylinder and having a valve closing member on one end thereof adapted to engage said valve seat, means for fixedly holding said piston within said valve body, and sealing means for slidably sealing said cylindrical member within said cylinder.

2. The valve assembly of claim 1 further comprising spring means in said cylinder positioned to urge said valve closing member against said valve seat, and said thermal motor is arranged to urge said valve closing member away from said valve seat upon heating of said thermally expandable material.

3. The valve assembly of claim 2 wherein said means for holding said piston comprises means within said cylinder for holding said piston on the side of said cylindrical member away from said valve seat.

4. The valve assembly of claim 1 wherein said cylindrical member has an external axially extending slot, further comprising key means in said inner cylinder and engaging said slot for inhibiting rotation of said cylindrical member.

5. The valve assembly of claim 3 in which said thermal motor is of the type having an electrical resistive heater within said cylindrical member, comprising electrical leads connected to said resistive heater extending through the end of said cylindrical member away from said valve seat, and sealingly extending through said sealed end of said cylinder.

6. The valve assembly of claim 1 wherein said means for holding said piston comprises means connected to said valve body adjacent said valve seat for holding said piston.

7. The valve assembly of claim 1 wherein said inlet and outlet extend through said valve body on a common axis transverse of the axis of said valve seat and cylinder, and said valve body comprises a first chamber on one side of said valve seat connected to one of said inlet and outlet, and a second chamber on the other side of said valve seat into which the other of said inlet and outlet extend, and into which said cylinder and said cylindrical member extend.

References Cited UNITED STATES PATENTS 7/1929 Johnson 60-23 4/1960 Dillman 60-23 X 3/1965 Schutmaat 25111 X 8/ 1967 Sherwood 2511 1 8/1968 Barnett 60-23 US. Cl. X.R.

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