US2186782A - Refrigeration apparatus - Google Patents

Description

Jan. 9, 1940. F. R. ERBACH 2,186,782

REFRIGERATION APPARATUS Filed Aug. 27, 1930 2 Sheets-Sheen 1 1e 5% .U IN VENTOR.

Fame/0:2. EEBHCH Patented Jan. 9, 1940 UNITED STATES REFRIGERATION APPARATUS Frederick R. Erbach, Detroit, Mich., assignor, by

mesne assignments, to Nash-Kelvinator Corporation, Maryland Detroit, Mich.,

a corporation of Application August 27, 1930, Serial No. 478,172

16 Claims.

This invention relates to refrigerating apparatus employed for liquid cooler purposes and more particularly relates to automatic suction cut oif valves for employment in such mecha- A nism. I

The object of this invention is to provide a suction cut off valve to be used with a flooded refrigerant evaporator which will automatically close the suction lines associated with the evap- W orator when the interior of the evaporator reaches a predetermined low temperature.

Difficulty has been experienced heretofore in cooling liquids to a comparatively low temperature without occasionally freezing the liquid with m resulting damage to the refrigerating apparatus.

This occasional freezing-up has been found to take place due toa setting of the control switch for operation of the system at low temperatures when there are numerous demands for drinking 20 water at comparatively short intervals, such, for example, as in schools, oifices or steel mills and the like. In practice, it has been found that the control switch may be set to operate the system so that the refrigerant in the evaporator 26 is at a temperature about or below freezing when there are numerous demands at short intervals without the possibility of freezing the water to be cooled owing to the heat of the incoming water which prevents such freezing. Under such 30 conditions, the switch is likely to be purposely set too low or misadjusted when attempting to take care of the peak demands. However, in schools, oflices or steel mills which operate but five or six days a week, it has been found that over the weak-ends or holidays when there is no demand for water, the system cycles by heat leakage through the insulation into the cooler which warms up the system sufficiently to start the compressor operating. In the event the 40 switch is misadjusted and no incoming warm water is had the temperature of the refrigerant in a flooded evaporator is at an abnormal or undesired low value which during the on-phase of the refrigerating cycle causes some ice to be frozen on the outer wall of the evaporator. Also, when the switch is set to operate the system below freezing during such demands, the system will operate at undesired low temperatures when there is no demand for drinking water. During ,0 the off-phase of the refrigerating cycle, with such switch setting, it has been found that all of the ice does not melt, thus resulting in some of the ice remaining on the outer wall of the. evaporator. Under these conditions, there is a cumulative freezing on the outer surface of the take care of the peak demands and over a week- 5 end or a holiday, the switch sticks or becomes otherwise faulty in operation, the temperature of the refrigerant in the evaporator would fall to an abnormal low value, resulting in freezing-up of the system. In addition, the switch may be set 1 to operate the system so that the refrigerant in the evaporator is below freezing during a peak demand, and if the switch should become faulty in operation, the temperature of the refrigerant may reach an abnormally low value which is sufl5 flciently low enough to cause a freeze-up of the cooler even though there are numerous demands for drinking water at short intervals. Thus, it is an inherent characteristic of a water cooler, for different reasons, to freeze up occasionally when 20 attempting to cool large quantities of water to the desired temperature, unless some provisions are made to prevent such conditions.

This invention provides a suction out off valve which, when used with a refrigerating apparatus 25 employing a flooded evaporator and a low side pressure controller, will automatically lower the pressure in the suction line to such an extent as to cause the pressure controller to shut off the refrigerant compressor before the liquid which is being cooled is frozen.

In the drawings:

Figure I is a vertical cross sectional view of a flooded refrigerant evaporator showing a suction cut off valve embodying this invention in an a opening therein communicating with the suction line.

Figure II is an end view in elevation of the evaporator shown in Figure I.

Figure III is an enlarged side elevational view at of a suction cut off valve embodying this invention.

Figure IV is across sectional view of the suction cut ofi valve shown in Figure III.

The suction out off valve embodying this inven- 45 tion isemployed in the present instance with a refrigerant evaporator l3 consisting of two cylindrical shells l4 and I5 one disposed within the other in spaced relation thereto, and having their adjacent ends sealed together as at 8. The 50 inner shell I4 is spirally corrugated forming a circulatory passageway between it and the outer shell I5 through which the liquid to be cooled is circulated.

Liquid enters this passageway through an opena ing I6 and is withdrawn through an opening IT. The openings l6 and H are threaded to receive similarly threaded conduits. The inner shell is provided with a sealed closure 1 at one end and at the other with an annular shoulder member 6 secured in fluid tight contact therewith and carrying threaded openings to receive bolts 5 which secure a head I2 in position.

Liquid refrigerant from a refrigerant compressor condenser structure by conduit 4| is admitted to the evaporator through an opening l8 in the head l2. Its admission is controlled by a needle valve l9 which is operated by a float 20 carried on one end of a bell crank lever 2| to which the needle valve is pivotally connected and which is itself pivotally connected to the extremity of an interiorally projecting arm 9 carried on the interior surface of the head 12.

A suction cut off valve III is threaded into one side of an opening I l in the head l2, to the other side of which is connected a suction line 42 leading to the refrigerant compressor condenser structure 40. The suction cut off valve II] is provided with a port 22 which is in open communication with the suction line 42 when the valve is in an open position. Evaporated refrigerant fluiid when withdrawn from the evaporator I3 passes through the port 22 in the suction cut off valve l0 into the opening II and through the suction line associated therewith to the compressor 44.

The suction cut off valve I0 consists of cylindrical shell 23 constructed of highly conductive metal, having a port 22 formed therein and provided with a shoulder 24 having surfaces adapted to be engaged by a tool for revolving the shell. Beyond the shoulder 24 the shell 23 is provided with a reduced portion 25 threaded for engagement with similar threads on the inner side of the opening II in the evaporator l3. An opening 26 through the reduced portion 25 leading into theinterior of the shell 23 is provided at its inner extremity with a valve seat 21 adapted to receive a valve 28. A valve stem 29 carried by the valve 28 is rigidly secured to a closure 36 for one end of an expansible bellows 30. The opposite end of the bellows is provided with a closure 31 having an opening 3| therein which also forms a closure for an opening 38 in the shell 23. The interior surface of the closure 31 is made concave as at 33.

A short length of pliable tubing 32 is fitted into the opening 3! and secured in fluid tight contact therewith. A liquid having an ascertained freezing point and cubical expansion upon freezing is introduced into the bellows 30 through the tubing 32 filling the bellows completely. The convex surfaces 33 of closure 31 make possible the expulsion of all air when the bellows 30 is filled with liquid. After the bellows has been filled with liquid, the tubing 32 is pinched off as at 34 sealing the liquid within the bellows. With the bellows full of liquid the valve 28 assumes the position shown in Figure IV. When the contents of the bellows freezes and expands, the valve 28 engages the valve seat 21.

A spiral spring 35 is positioned between the bellows closure member 36 and the interior wall of the shell 23 adjacent to the valve seat 2'! to collapse the bellows 30 when its contents are in a liquid state and cause the valve 28 to be withdrawn from its seat 21.-

It will be apparent that when the suction out off valve I0 is installed in an evaporator l3, as above described, and the evaporated refrigerant fluid surrounding the shell 23 and passing therethrough is at a temperature which will freeze the,

contents of the bellows 30, the valve 28 will close the opening 26 and reduce the pressure in the suction line leading to the low side of a refrigerant compressor condenser structure 40 and cause a low side pressure controller 48 associated therewith to throw a switch cutting off the power which operates the compressor. It will also be apparent that when the temperature of the gaseous refrigerant surrounding the shell 23 rises enough to melt the contents of the bellows 30, the spring 35 will collapse the bellows and cause the valve 28 to be withdrawn from its seat permitting the flow of refrigerant through the opening 26 into the suction line. The bellows 30 may be filled with any liquid having a freezing point the same as or higher than that of the liquid to be cooled by the evaporator. Heat will be transferred from the contents of the bellows to the refrigerant within the evaporator l3 at a more rapid rate than from the liquid in the passageway between the shells l4 and I5 due to the excellent conductivity of the shell 23 and the fact that the refrigerant within the evaporator completely surrounds the shell 23 and the bellows 30. It is therefore possible to use a liquid within the bellows having the same freezing point as the liquid to be cooled, as the contents of the bellows 30 will become solidified and cause the refrigerant compressor 44 to shut off through the closing of the valve 28 before the liquid circulating between the shells and I5 is frozen.

It will be apparent to those skilled in the art that the structure disclosed herein is merely illustrative of the invention and that many modifications and changes may be made in such structure without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. In a refrigerating system of the flooded type, the combination with an evaporator of a. suction cut-01f valve disposed within said evaporator, and means responsive to abnormally low temperature changes in the evaporator for closing said valve.

2. A valve structure comprising an expansible bellows containing a freezable liquid sealed therein, a shell of highly conductive material surrounding the bellows, a refrigerant inlet port and outlet port in said shell, the movement of said bellows being primarily influenced by changes in temperature of said shell, and means operatively associated with the bellows for closing the outlet port.

3. A valve structure comprising a cylindrical shell having a valve port in one end and a refrigerant inlet port in one side, a bellows sealed with a freezable liquid disposed within said shell, a valve and valve stem operatively associated with said bellows for closing said valve port.

4. A valve structure, comprising: an expansible bellows containing a freezable liquid sealed therein, a shell of highly conductive material surrounding the bellows, a refrigerant inlet port and outlet port in said shell, the movement of said bellows being influenced by changes in temperature of said shell together with changes in temoutlet port when the liquid in the bellows changes to a liquid state.

5. In a refrigerating system, the combination with an evaporator having a refrigerant outlet port, and expansible means within the evaporator and containing a freezable fluid arranged for' entirely closing said port when said fluid is in a frozencondition and for entirely opening said port when said fluid is in an unfrozen condition.

6. In a refrigerating system, the combination with an evaporator having a refrigerant outlet port, a valve member co-operating with said port, and means. within said evaporator responsive to a predetermined low temperature for causing said valve to entirely close said port, said valve remaining in a stationary position until said evaporator attains said predetermined low temperature.

'1. In a refrigerating system, the combination with an evaporator having a header adapted to contain a quantity of liquid refrigerant, of means providing an outlet port in said header, and means in said header responsive only to abnormally low changes in temperature of the refrilgterant in the header for controlling said outlet p 8. In a refrigerating system, the combination with an evaporator having a header adapted to contain a quantity of liquid refrigerant, of means providing an outlet port in said header, and means in said header including an expansible element containing a freezable fluid in said header responsive to changes in temperature of the refrigerant in said header for opening and closing said outlet port.

9. In a refrigerating system, the combination with an evaporator of the flooded type having a header adapted to contain a quantity of liquid refrigerant, said header having an inlet port for the admission of liquid refrigerant and an outlet port for vaporized refrigerant, arid means within said header responsive to abnormally low changes of temperature therein for closing said outlet port.

10. A water cooler comprising a flooded evaporator, means conducting water to be cooled in thermal contact with the refrigerant in said evaporator; means to prevent freezing the water in said means comprising a thermostat controlled valve in the outlet for refrigerant gas from said evaporator, said valve including an expansible element containing a freezing fluid in the evaporator responsive to changes in temperature in said evaporator.

11. Refrigerating apparatus comprising an evaporator of the flooded type, a refrigerant condensing element associated with said evaporator, means for controlling the operation of said condensing element in response to changes in temperatures in said evaporator for normally maintaining a desired temperature, and additional control apparatus including an element in intimate metallic contact with the refrigerant in the evaporator and being arranged to modify the operation of said first named control means in the event the temperature in the evaporator reaches an abnormally low value to render the condensing element inoperative.

12. In a refrigerating system, in combination, an evaporator, means for supplying refrigerant to said evaporator, a suction line leading from said evaporator, a valve in said suction-line for controlling the flow of refrigerant therethrough,

and thermally responsive means actuated by a freezing solution contained therein for closing said. valve at a predetermined low temperature in said suction line.

13. In a refrigerating system, in combination, an evaporator, means for supplying refrigerant to said evaporator, a suction passage leading from said evaporator, a valve in said passage for controlling the flow of refrigerant therethrough, and an element in said passage containing a freezing solution for closing said valve when the temperature in said passage is maintained at or below a predetermined low value for an appreciable length of time.

14. In a refrigerating system, in combination, an evaporator, means for supplying refrigerant to said evaporator, a suction line leading from said evaporator, a valve in said suction line, and expansible and contractible means in said suction line and actuated by a freezing solution contained therein for moving said valve to control the flow of refrigerant through said line.

15. In a refrigerating system, in combination, an evaporator, means for supplying refrigerant to said evaporator including a compressor, a suction line leading from said evaporator, pressure actuated means connected with said suction line for controlling the operation of said compressor,- a valve in said suction line between said pressure actuated means and said evaporator, and a delayed action temperature actuated means in said suction line for controlling said valve, the last mentioned means comprising an expansible member enclosing a normally liquid material adapted to freeze and to expand after the extraction therefrom of the sensible heat contained therein to close said valve.

16. In a refrigerating system, in combination, an evaporator, means for supplying refrigerant to said evaporator, a suction line leading from said evaporator, a valve in said suction line for controlling the flow of refrigerant therethrough, and freezable liquid in the suction line for operating the valve, whereby said valve is affected by said liquid only after the absorption therefrom of the sensible heat contained therein.

FREDERICK R. ERBACH.

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