US2293867A - Valve mechanism - Google Patents

Description

Aug. 25, 1942. P C TEMPLE l2,293,867

VALVEl MECHANISM Filed June 29, 1939 .PA UL C. TEMPLE' Patented Aug. 25, 1942 UNITED STATES PATENT OFFICE VALVE MECHANISM Paul C'. Temple, Decatur, Ill., assignor to A. W. Cash Company, Decatur, Ill., a corporation of Delaware This invention relates to valve mechanisms, and more particularly to valve mechanisms of the type adapted to control the flow of iluid in accordance with pressure variations as well as changes in liquid level.

In certain apparatus for the manufacture of ice it has been proposed to employ a vessel forming a heat exchanger arranged to effect a transfer of heat from water, through intervening metal Walls, to a suitable refrigerant in liquid form. As soon as the water has been frozen, refrigerant in gaseous form is introduced at a higher pressure to force the liquid refrigerant out of the vessel and into an elevated storage tank or accumulator. The ice is thenA discharged and the liquid is drained back into the vessel for a repetition of the cycle. The vessel and tank are connected by a conduit provided with a valve which must be open at the proper time to allow transfer of the liquid to the tank and closed promptly when the transfer has been effected. Furthermore, the valve must be opened again to allow the return of the liquid to the vessel. So far as I am aware, no valve mechanism suitable for this purpose has been disclosed heretofore.

It is accordingly one object of the invention to provide a simple, inexpensive and reliable valve mechanism particularly suitable for controlling the iiow of liquid refrigerant from a heat exchanger to a storage tank and return.

It is a further object of the invention to provide a valve mechanism arranged to close automatically upon a predetermined reduction in liquid level, and to open automatically upon a predetermined reduction in pressure irrespective of the reduced liquid level.

It is a further object of the invention to provide a valve mechanism particularly adapted to control the flow of liquid back and forth between a vessel and storage tank, this mechanism being so constructed and arranged as to permit flow from the vessel to the tank when the pressure in the Vessel is increased, to close when the liquid in the vessel has dropped to a predetermined level, and to open when the pressure is reduced irrespective of the reduction in liquid level.

With these and other objects in View, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specication and covered by the claims appended hereto.

Referring to the drawing illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. 1 is a Vertical longitudinal section through a valve mechanism;

Fig. 2 is an enlarged sectional view of the pilot valve shown in Fig. 1;

Fig. 3 is an enlarged section on the line 3-3 of Fig. 2; and

Fig. 4 is an elevation showing the valve mechanism connected to other apparatus.

The embodiment illustrated comprises a hollow valve body lil dividedf internally by a U- shaped partition II into an inlet chamber I2 and an outlet chamber III. The partition II isV provided with two aligned ports I5 through which fluid may iiow under the control of a vertically reciprocable seating-type main valve I6. This valve is biased upwardly toward its open position by a coiled compression spring I8 located beneath the'valve and supported by a cap I9 secured to the bottom of the body It). This cap is shaped to provide a guideway 2i) for a vertical stem 2l which extends downwardly from -the valve I6.

A bonnet 23 is secured to the top of the body I0, this bonnet being shaped to provide a vertical cylinder 24 directly above the Valve I6, with the lower end ofthe cylinder in communication with the outlet chamber I4. A piston 25 isslidably mounted in the cylinder 24 and connected to the valve I6 by a vertical rod or stem 26. This piston provides a huid-pressure actuated device which will, under certain conditions, close the Valve IE in opposition to the force of itsrbiasing spring I8.

The fluid pressure effective on the piston 25 is controlled Vby a pilot valve which in turn is actuated in accordance with variations in the level of a liquid. For this purpose the bonnet- 23 is dividedinternally by suitable partitions to provide two chambers 28 and V29, with an intermediate chamber 30 between them. The chamber 28- is connected by a pipe 32 to the outlet chamber I4 in the body I0, .and the intermediate chamber 3E) opens directly into the upper end of the cylinder 24. the interior of a hollow casing 34 which-is secured to the bonnet 23 at one side thereof.v This Y casing 34 has'a screw-threaded opening v36 in itsV upper portion, and its lower portion` is connected to the inlet chamber I2 in the body I0 by means of a pipe 3l provided with a manually adjustableY needle valve 38 which is partially cpenginjthe normal operation of theapparatus.V vComfnunil cation between theintermediate chamber A3|) and thechambers 28 and `29 located on opposite sides The chamber 29 communicates directly with i thereof is controlled by a suitable three-way pilot valve mechanism.

The preferred construction for this pilot valve mechanism is shown in detail in Fig. 2 and comprises a cage 48, formed in two parts for convenience in assembly, and screw-threaded externally to facilitate its mounting within the bonnet 23. This cage is shaped to provide a central recess 42 from which ports 44 lead laterally to the intermediate chamber 30. In addition an outlet port 45 connects the recess 42 with the chamber 28, and an inlet port 46 connects the recess 42 with the chamber 29. A horizontally reciprocable pilot valve 48 is mounted within the recess 42, this valve having a stem'49 extending therefrom through the port 45 and a stem 50 extending therefrom through the port 46. These valve stems are smaller in diameter than the ports and they are provided with radial ribs I (Fig. 3) which slidably engage the walls of the ports to guide the valve in its horizontal travel. The valve stem 49 engages a small piston 53 which is slidably mounted in a cap 54 secured to the bonnet 23, this piston being urged against the end of the valve stem by means of a small coiled compression spring 55. By this construction the valve 48 is biased toward the port 46.

'Ihe pilot valve 48 is controlled by means responsive to the level of liquid in the casing 34, and for this purpose I prefer to utilize a hollow spherical float 51 which is mounted on one end of a horizontal lever 58. 'Ihe other end of the lever engages the end of the valve stem 5D and is supported by a block 59 which is fulcrumed on a pin 68 supported by the bonnet 231. yThese parts are so constructed and arranged that if the float 51 moves upwardly the spring 55 will move the pilot valve 48 to the left and close the port 46, whereas if the float moves downwardly the lever 58 will move the pilot valve to th'e right and close the port 45.

The valve mechanism described above is particularly adapted to control the flow of liquid refrigerant. As indicated in Fig. 4, the inlet chamber I2 in the valve body I0 may be connected by a pipe 62 to a vessel 63, and the outlet chamber I4 may be connected by a pipe 64 to an elevated tank 66. The opening 36 in the top of the casing 34 is connected by a pipe 61 to the vessel 63. This vessel 63 is a heat exchanger of known construction arranged to form ice by transferring heat from water to a refrigerant in liquid form.

The operation of th'e invention will now be described. During the freezing cycle in vessel 63 this vessel will be lled with a suitable liquid refrigerant, such as ammonia, to a comparatively high level, the pressure being maintained at a predetermined pressure of say 30 pounds per square inch. Because of the high liquid level the iloat 51 will be held in its raised position, and the port 46 will be closed by the pilot valve 48. The upper end of the cylinder 24 will be in communication with' the lower end thereof through the chamber 30, ports 44, recess 42, port 45, chamber 28, pipe 32 and chamber I4. Consequently the uid pressures on opposite sides of the piston 25 will vbe equal, and the spring I8 will hold the main valve I6 upwardly in its open position. However, no flow will take place through the ports I5, since the fluid pressure in the chamber I4 caused by the hydrostatic head of liquid in the pipe 64 will be equal to th'at in the chamber I2. When the freezing cycle has been completed, ammonia in gaseous form will be admitted to the vessel 63 at a substantially higher pressure of say pounds per square inch, and this pressure will overcome the above-mentioned hydrostatic head and force the liquid ammonia out of the vessel 'and through the pipes 62 and 64 to the elevated tank 66. When the liquid level in the vessel 63 h'as fallen suiiiciently the float 51 will descend and the pilot valve 48 will be moved to the right, opening the port 46 and closing the port 45. This will admit the high pressure fluid through the port 46 to the upper end of the cylinder 24, and since the pressure in th'e chamber I4 is appreciably less than the pressure in the vessel 63, because of the pressure drop through the pipe 62 and the ports I5, the piston 25 will be forced downwardly in opposition to the spring I8, closing the main valve I6. As soon as the ice has been discharged from the vessel 63, the pressure in this vessel will be restored to 30 pounds, and because of the reduced pressure on the top of the piston 25 th'e spring I8 will move the main valve I 6 upwardly to its open position. Thereupon the liquid ammonia will flow back by gravity from the tank 66 to the vessel 63, and the cycle will be repeated. During the operation of the valve mechanism the needle valve 38 will remain in a partially open position to throttle the flow of the liquid through the pipe 31 as th'e liquid level changes, thus preventing the oat 51 from moving too suddenly.

It will now be apparent that the invention provides a valve mechanism of a simple and reliable construction adapted to control the flow of a liquid in accordance with both the pressure and the level of the liquid. The main valve will close automatically when th'e liquid level has dropped sufficiently, and it will open automatically when the pressure is decreased, despite the lowered level. While this mechanism is particularly suitable for use in the control of liquid refrigerants, various other uses will occur to those skilled in the art.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In combination with a vessel arranged to be filled with liquid refrigerant at a predetermined pressure, a tank, a conduit connecting the lower portion of the vessel to the lower portion of th'e tank, the tank being elevated so that there will be suficient hydrostatic head of liquid in the conduit to prevent flow into the tank while the refrigerant in the vessel is at the said predetermined pressure, a valve to control the flow in the conduit, a iloat immersed in the liquid and movable vertically between an upper and a lower position in response to changes in the level of th'e liquid in the vessel, valve opening means arranged to maintain the valve in its open position when the fioat is in its upper position, and valve closing means arranged to respond to the pressure of the refrigerant in the vessel and to close the valve when the pressure of the refrigerant in the vessel has been increased materially above the said predetermined pressure to force the liquid from the vessel into the tank and the float has reached its lower position, the valve opening means opposing the valve closing means with suiiicient force to overcome the effect of the said predetermined pressure on the valve closing means but with insucient force to overcome the effect of the materially increased pressure thereon, whereby the Avalve will return to its open position when the pressure of the refrigerant in the vessel is restored to th'e said predetermined pressure to therebyallow the liquid refrigerant to return by gravity from the tank to the vessel. Y

2. In combination with a vessel arranged tobe lled with liquid refrigerant at a predetermined pressure, a tank, a conduit connecting the lower portion of the vessel to the lower portion of the tank, the tank being elevated so that there will be suicient hydrostatic head of liquid in the conduit to prevent flow into th'e tank while the refrigerant in the vessel is at the said predetermined pressure, a main valve to control the flow in the conduit, a fluid pressure actuated device connected to the valve to close the same, a pilot valve arranged to control the ow of refrigerant from the vessel to the device, a float immersed in the liquid and movable vertically between an upper and a lower position in response to changes in the level of the liquid in the vessel, connections between the float and the pilot valve to open the pilot valve when the float is in its lower position and to close the pilot valve when the float is in its upper position, and means biasing the main valve toward its open position with a force sufficient to overcome the effect of the said predetermined pressure on the fluid pressure actuated device but insuicient to overcome the effect of a materially higher pressure thereon, whereby the liquid may be transferred from the vessel to the tank and vice versa by merely varying the pressure in the vessel and yet the main valve will close to prevent discharge of the liquid from the vessel below a predetermined height,

PAUL C. TEMPLE.

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