US2291503A - Control - Google Patents

Description

y 28, 1942- L. M. PERsoNs 1,503

Filed Sept. 14, 1938 CONDENSER MODULAT/NG 4r roRA/EK Patented July 28, 1942 UNITED STAT CONTROL Lawrence M. Persons, St. Louis County, Mo., as.-

signer to Automatic Control Corporation, St. Louis, Mo., a corporation of Delaware Application September 14, 1938, Serial No. 229,838

1 Claim.

The present invention relates generally to controls and to control methods, and more particularly to amethod of operating a cooling unit, air

conditioner, or the like, andto a control therefor.

The conventional cooling unit or air conditioner in use today includes a compressor which alternately compresses the cooling medium and stands idle. Hence, there are alternate periods of noise and of quiet. At the present time, cooling units are used in bedroomsduring the summer for the purpose of maintaining the-temperature substantially uniformly comfortable. The sleeper, therefore, is subjected to the continuous starting and stopping of the compressor which, i

even though mufiled, comprises a positive disturbance. It has been ascertained through tests, however, that a compressor which runs continuously during the night does not materialh disturb a sleeper.

Therefore, an object of the present invention is to provide a control for cooling units, air conditioners, and the like, which is adapted to maintain the temperature within a selected range and which permits continuous operation of the compressor. Another object is to provide a method of operating a cooling unit, or the like, whereby the compressor runs continuously.

Another object is to provide a method of operating a cooling unit, or the like, wherein the compressor runs continuously and the amount of cooling medium passed to the compressor is determined by a valve disposed in the cooling medium line upflow thereof.

Another object is to provide a control for cooling units, and the like, which includes a thermally actuated modulating valve.

Another object is to provide a control for cooling units, and the like, whereby the compressor and expansionvalve of the cooling unit are at all times operative and in which the amount of cooling medium passed directly to the compressor is determined by a valve in the cooling medium line which is controlled by a solid-charge thermostat.

Another object is to provide an eflicient control system for cooling units, and the like, whereby the compressor runs continuously, even though at times it may not be compressing the cooling medium.

Another object is to provide a control system for cooling units,and the like, which is eflicient and positive in operation.

Other objects and advantages will be apparent from the following description, taken in conjunction with the accompanying drawing, in which: I

Fig. 1 is a diagrammatic view of a cooling unit including an embodiment of the present invention disposed in operative relation therewith; and

Fig. 2 is a central longitudinal section through a valve and its associated operating mechanism which regulates the flow of cooling medium to the compressor of the cooling unit.

Referring to the drawing more particularly by reference numerals, there is shown in Fig. 1 diagrammatically the several elements of a cooling unit generally'designated ID. The cooling unit l includes a compresspr II, a condenser I2, a receiver I3, an expansion valve M, an evaporator l5, and cooling medium line segments l6, l1, l8, I9, 20 and 2|.

In the conventional type of cooling unit N1, the expansion valve is pressure and temperature controlled through suitable mechanism, whereby the compressor is alternately started and stopped. However, in the present invention, a control valve mechanism generally designated 25 is located in the system between the evaporator l5 and the.

compressor II at the juncture of the cooling line segments and 2|.

The control valve mechanism includes a casing 26 of the configuration shown inthe drawing. The casing 26 comprises a lower por tion 21 and an upper portion 28 which are main tained in assembled relation by screws 29 (Fig. 1) and which portions are sealed by members 24.

The lower portion 21 of the casing 26 includes vertically spaced horizontal bores 30 and 3| which are connected by a passageway 32, a vertical bore 33, and a chamber 34. The several bores 30, 3| and 33 and the chamber 34 are in communication as is evident from an inspection of Fig. 2.

The bore 33 and the chamber are separated by a wall 35 through which is a circular aperture 36 aligned with the bore'3l.

A double-ended valve 40 is disposed across the bore 33 with, fins 4| disposed within the bore 3| and fins 42 within the aperture 36. The fins 4| extend from a valve head 43 adapted to close the bore 3| in one position thereof while the fins 42 extend froma valve head 44 adapted to close the aperture 36 in one position thereof. The valve heads 43 and 44 are adapted to be in closing positions simultaneously. A stem 45 connects the valve heads 43 and 44 and extends beyond the valve head 44 to form a projection 46v The valve 4|! is biased to the right (Fig. 2) by a helical spring 48 which is disposed between the ends of end of the bore II. A stop it limits the movement of the .valve II to the right.

Within the upper portion 28 is a cup 53 and an associated nestled diaphragm 54 of a fluid actuated thermostat 55. The cup 53 includes a skirt II which extends between the upper portion 29 and the lower portion 21 of the casing "in a manner to maintain the thermostat II in its operative position. A fluid tube 51 is connected to the cup 53 at 59 and communicates between the cup I: and the diaphragm 54. A fluid bulb 59 is connected to the tube 51. The bulb 89 is disposed in the intake air stream of the evaporator I! in a manner shown by Fig. l. A stub shaft." is fixed to the diaphragm II.

A lever 85 of the configuration shown in Fig. 2 is pivoted to the cup 59 on a shaft 96. The lever .65 includes a J-shaped portion 91 and ears it which are pivotally connected to the shaft 66. The long leg of the J-shaped portion 61' terminates adjacent the projection 46 of the valve 40. A helical spring has one end disposed about the short leg of the 'J-shaped portion 91 and the other end against the bight II of a U-shaped member I2 and around a screw 13 which extends through the bight II. The U- shaped member 12 is fixed within the housing 28 in any preferred manner. The lever 65, therefore, is biased by the spring Hi towards clockwise movement.

An adjusting device 15 comprises a shaft 76, which threadedly engages the upper portion 28, and contacts the outer face of the cup 53. A knob 11 is fixed to the shaft I6 by a set screw 18. A stop 19, fixed to the upper portion 28 by a screw 80, limits the downward movement of the shaft 18. I

Referring to Fig. 2, the cooling medium flows into the control valve mechanism from the inlet pipe whence it flows both through the bore 30, the passageway 32, the bore 3|, around the fins 4| into the bore 33 and out the exit pipe 2| and through the bore 30, the chamber 34, around the fins 42 into the Here 33 and out the exit pipe 2|. The balanced valve 40 permits and requires this manner of flow of the cooling medium.

Operation -ed by the cooling unit iii. In instances where small units are used for regulating the temperature of bedrooms, and the like, of course, the whole mechanism will be within the room. In all, installations the bulb 59 is exposed in a manner to prevent bias from the heat of the compressor ll, so that it may function in accordance with the actual temperature of the room. Assume that the selected temperature for the room is 75 F., that the valve 40 will be fully closed to stop flow of the cooling medium when the temperature of the room drops to 70 F., and that it will be fully opened when the temperature of the room rises to 80 F. Were there no interfering conditions, the temperature of the room would be maintained constantly at the selected 75 F. and hence the valve 40 would be maintained in one specified position relative to its valve seat. However, ideal operating conditions seldom exist, since unexpected and unusual inflows of hot air, and the like, make demands upon the cooling unit, necessitating the passage to the compressor' ll of a greater amount of cooling medium. Similarly, certain conditions give rise to an excess of cool air, necessitating a diminution of the cooling medium passing to the compressor ll.

When the temperature within the room is 75 F., the elements of the valve mechanism will be disposed in an initial relationship. Should I the temperature of the room rise to 77 F., then the thermally sensitive fluid within the bulb 59 expands in accordance therewith to move the stub shaft downwardly (Fig. 2), thereby pivoting the lever 65 counterclockwise against the force of the spring 10 to permit the balanced valve 40 to be moved to the right by the force of the spring 49. Movement of the valve 40 to the right allows more cooling medium to pass to the compressor I l and subsequently to the evaporator l5, thereby supplying more means for removing the heat from the air passed through the evaporator l5. When sufllcient heat has been removed from the atmosphere of the room, the temperature falls to the selected temperature of 75 F., thereby causing a reversal of the movement train Just described, which restores the valve 49 to its initial position.

Should the temperature of the room drop below 75 F., the thermally sensitive fluid within the bulb 59 contracts to allow the stub shaft 60 to be moved upwardly, thereby permitting the lever 65 to pivot clockwise through the force of the spring 10 to move the valve 40 to the left, thereby shutting down on the flow of cooling medium passing the valve 40. This closing movement of the valve 40, of course, cuts downon the amount of cooling medium passing to the compressor H and to the evaporator 15. Hence, the amount of heat taken from the atmosphere of the room is reduced, which permits the temperature to return to the selected temperature of 75 F. As the selected temperature of 75 is regained, expansion.of the thermally responsive fluid within the bulb 59 effects a reversal of the movement train just described and restores the valve 40 to its initial position.

The adjusting mechanism 15 provides a means for selecting the temperature to be maintained by the cooling unit. The shaft 16 is moved by means of the knob I1 upwardly or downwardly to increase or to decrease the space between the cup 53 and the diaphragm 54. Since this space is connected by means of the tube 51 with the bulb 59 this movement of the knob 11 lowers or raises the temperature range through which the valve 49 acts. In other words, by means of theadjusting mechanism I5, the valve 40 can be set to maintain the temperature of the room at any selected temperature. i

It is apparentthat the lever -65 is of a configuration and is located relative to the stub shaft 60 and the valve 40 to effect a movement of the valve 40 which is a multiple of the movement of the stub shaft 60. The ratio of movement is determined by the distances of the stub shaft 60 and the valve 40 from the pivot shaft 66. This ratio is, of course, predetermined for an instant assemblage.

It is to be understood that the present invention contemplates the use of specific constructrol valve mechanism may be disposed elsewhere in the system than as shown.

It is to be understood further that the foregc ing description'and accompanying drawing have been given by way of illustration and example and not for purposes of limitation, the invention being limited only by the claim which follows.

What is claimed is:

A control valve comprising a housing, means for introducing a fluid into said housing, means for exiting a fluid from said housing, two passages for fluid between said means, a balanced valve disposed in said housing adapted to close both passages in one position and to open both passages in another position, a bellcranklever pivoted in said housing having one arm contiguous to the balanced valve, thermostatic means for positively pivoting said lever to move said arm away from said valve, spring means disposed in one passage acting on said valve to force said valve to follow the contiguous lever arm, and

Images