US2122210A - Cooling apparatus - Google Patents

Description

E. F. MILLER COOLING APPARATUS Filed May 22, 1934 'INVENTOR ERNEST F2 MILLER Patented lune 28, I938 A UNITED ST Ernest F. er, Prospect Park, Pa, assior Westinghouse Electric & Manufact m PAS to Company, East Pittsburglnlfa, a con-potion of Pennsylvania Application 1d illaims.

My invention relates to control mechanism, more particularly to control mechanism for vapor jet refrigerating apparatus, and it has for its object to provide improved control mechanism.

A further object is to provide mechanism for controlling the various operating devices of the refrigerating apparatus to provide automatic refrigerating action.

Another object is to provide vapor jet refrigerating apparatus for cooling air and means for shutting off circulation of air over the cooling element in the event that the jet in the ejector fails and causes heating of the cooling element.

A further object is to provide control mechanism, for vapor jet refrigerating apparatus, including automatic means for intermittently initiating and terminating cooling operation of the apparatus, a main switch for rendering the mechanism operable or inoperable, and means for establishing vacuum in the condenser as soon as the main switch renders the apparatus operable and independently of the action of the automatic means.

In accordance with my invention, I provide control mechanism including a main switch whereby the refrigerating apparatus may be either shut down or rendered operable. When this switch is positioned to render the apparatus operable, the control mechanism effects con-= tinuous operation of the pump for removingcondensate from the condenser, and also of the pump for efi'ecting circulation of chilled water through the evaporator when such pump is used. Thermostatic means responsive to refrigeration demand effects intermittent operation of the ejector and of the cooling fluid circulating means for the condenser. The thermostatic means is operable only when the main switch is positioned to render the apparatus operable.

I also provide means which operates, in case there is not sufiicient liquid in the apparatus for cooling action when the main switch renders the apparatus operable, to provide the necessary liquid Ly condensing motive fluid supplied to the ejector. e

I also provide means responsive to a high tem perature of the liquid in the evaporator for terminating circulation 'of air over the cooling element, thereby preventing the delivery of heated air.

These and other objects are effected by my invention, as will be apparent from the following description and claims, taken in connection with v the accompanying drawing forming a part of this application, in which:

Fig. l is a diagrammatic view, in elevation, of apparatus embodying my invention;

circuits; and,

' wardly.

22, 1934, semi No. 126,939

(on. em)

Fig. 3 is a diagrammatic view of a modified air circulating arrangement.

Referring to the drawing in detail, I show an evaporator It, which also serves, in this case, to cool air directly. The evaporator includes a cas- 5 ing ll, upper and lower headers l2 and i3, and cross finned tubes l4 extending between said headers and providing free communication therebetween.- The interior of the headers and the tubes constitutes the evaporating chamber. The casing H is formed with an inlet I5 through which air to be cooled is conveyed to the evaporator and into contact with the outer surfaces of the tubes M. The evaporator is also formed with an outlet l6, connected to a duct l'l, through which the cooled. air is delivered to an enclosure it.

i A fan l9, driven by an electric motor 2 l, is provided to efiect said'circulation of air. The enclosure lt may be any enclosed space which is to be provided with cooled air; for example, it may be a space occupied by people, such as, the interior or passenger space of a railway passenger car.

. Suitable spray means, such as a manifold 22 25 and a plurality of spray nozzles 23 mounted thereon, are provided in the upper header l2 and arranged to direct a spray of refrigerant liquid particles into the upper ends of the tubes it. The refrigerant is usually water, which liquid will be referred to hereinafter without restricting the invention thereto. An ejector or thermal compressor 2% is provided to effect a reduced pressure within the evaporating chamber by removing 'vapor therefrom, and has its suction inlet 25 connected, in the illustrated embodiment, to the lower header it through a conduit 26. Vapor for motivating'the ejector, usually steam, is supplied to the ejector through a conduit 27!. A

valve it, operated by a solenoid 8B, is provided 40 to control the supply of steam through the conduit 2i.

A condenser ii is connected to the outlet of the ejector for condensing the vapor discharged therefrom, including the vapor withdrawn from the evaporator chamber and the expended motive fluid. The condenser includes headers 32 and 33, and tubes 34! extending therebetween. The headers and tubes contain the vapor to be condensed, the header 32 being connected to the ejector outlet. An auxiliary ejector 35 has its suction inlet connected to the header 33 for removing air and non-condensable gases from the condensing space of the condenser. The cooling fluid, which is preferably air, is circulated in contact with the outer surfaces of the tubes. by a fan 36 driven by an electric motor 31. With the apparatus arranged as shown in Fig. 1, the fan 36 effects flow of air either forwardly or rear- The condenser is provided with a pressure relief valve 38, shown as connected to the header 32, and arranged to discharge steam through a conduit 39 to outdoors in the event that the pressure in the condenser assumes a dangerously high pressure, as by failure of the air removal means.

To increase the cooling eflfect, I provide evaporative cooling of thecondenser tubes. Nozzles ll, carried by upper and lower manifolds 52, are provided to spray water into the circulating air stream and onto the outer surfaces of the tubes. The Water'is evaporated by the circulating air, thereby augmenting the cooling effect available for condensing vapor within the tubes.

The water circulating system provides circulation of water through the evaporator l0, a supply of condensate from the condenser iii to the evaporator to 'relace evaporated water, and delivery under pressure to the condenser spray nozzles 5| of the remaining condensate and of unevaporated condenser spray water. The lower header it of the evaporator I0 is formed with a drain outlet 43 connected, through a conduit M, to the inlet of a water circulating pump 65. The outlet of said pump is connected through a conduit dB to the nozzle manifold 22. The conduit 36 is provided with a strainer 51. It may also be formed with a branch conduit 68 communicating with a pressure relief valve 69 disposed in the evaporating chamber, for example, in the lower header l3 of the evaporator. In the event of clogging of a number of nozzles 23 or of the strainer 35a suflicient to build up pressure within the conduit 56 to an undesirable point, the pressure relief valve 59 opens and discharges water into the lower header l3, thereby avoiding possible damage to the pump 85.

The condensate formed in the condenser 3| collects in the headers 52 and 33 which are connected to a drain'conduit 5|, through which the condensate flows downwardly by gravity. The conduit 5| is connected to the conduit 35, through parts presently described, for the purpose of supplying make-up water to the evaporator; that is, water for replacing that evaporated in the evaporator. The conduit 5| has a branch 52 which is connected to a float chamber 58. A float valve 54, actuated by a float member 55 within said chamber, controls the flow of liquid from the branch conduit 52 into the float chamber. The latter is connected through a conduit 56 with the conduit 36 for supplying liquid thereto. The float valve 54 serves to control the flow of condensate to the conduit 54 to maintain a predetermined level of liquid within the float chamber 55, the valve decreasing the flow of condensate as said level tends to rise and increasing said flow as the level tends to drop. The upper part of the float chamber 53 is connected to the evaporator, at any suitable point, such as, the header l2, through a vent pipe 51. The same level of liquid is maintained, therefore, within the conduit 55 and the float chamber 53.

The conduit 5| is also connected, through a connecting portion 58, to a conduit 59, which conveys the remaining condensate to the inlet of a circulating pump 5|. The pumps $5 and Si may be gear pumps, as shown, and are preferably driven by a common sourbe of power, such as an electric motor 63. The pump 6| discharges water under pressure to a conduit 52, which conveys the same to the nozzle manifolds M. portion of water sprayed onto the condenser tubes at one time is evaporated so that it is necessary to recirculate the unevaporated water. This water is collected by a drip pan 6 3 having a sump Only a small 65, from which it flows through a conduit 66, a float chamber 61, a conduit 68, a float chamber 69, and a conduit H, to the conduit 59, in which it is added to the condensate flowing to the pump iii.

The conduit 62 is provided with'a strainer I2. It is also provided with a branch conduit 13, located ahead of the strainer 12 and communicating with apressure relief valve 14, which is arranged .to discharge water onto the drip pan 6d. The purpose of the pressure relief valve M is to prevent the building up of an undesirably high pressure, in the event of clogging of a number of nozzles 5| or of the strainer 12, which might damage the pump 6|.

Within the float chamber 61 is a float valve 15 I having a float member l5 controlled by the level of liquid in the float chamber. The purpose of the float valve 15 is to prevent the admission of air from the atmosphere to the condenser through the water-circulating conduits in the event that the quantity ofunevaporated spray water in the float chamber 61 is insuflicient to immerse the end of the conduit 58. As the water level in the float chamber 61 drops, due to any the admission of unevaporated condenser spray water to the condenser 3| to an amount which) together with the condensate flowing thereto from the condenser, does not exceed the capacity of the pump 6|, thereby assuring that all con-' densate will be removed from the condenser. The

float valve 18 includes a float member 19 responsive to the level of liquid in the float chamber 69, a

will be apparent that condensate formed in the condenser SI and not supplied to the conduit M may flow unrestricted to the pump 6|. Any increase in the quantity of condensate will tend to raise the level of the liquid in the float chamber G9 and restrict the admission of unevaporated condenser spray water.

The operation of the refrigerating apparatus is as follows: The water sprayed from the nozzles 23 in the evaporator l0 flows downwardly through the interior of the tubes, a portion of said water being evaporated by the heat extracted from the air circulated over the tubes. The vapor is withdrawn from the evaporator by the ejector 24 and discharged, together with the expended motive fluid, into the condenser 3|. The action of the ejector maintains a low absolute pressure in the evaporating chamber, thereby effecting cooling by evaporation of water. The unevaporated water collecting in the lower header l3 flows by gravity through the conduit M to the pump 45, by which it is circulated through the conduit 46 to the nozzles 23. The valve 56 is operated in response to the water level in the float chamber 53 to dmit a quantity of condensate from the condenser 31! which is sufiicient to maintain said water level substantially constant and which replaces the water evaporated within the tubes l4.

The remainder of the condensate from the condenser flows unrestricted through the conduits H and 59 to the pump 6!, by which it is circulated through the conduit 62 to the spray nozzles 46. From the latter, it is directed onto the exterior surfaces of the condenser tubes 34 to provide evaporative cooling of said tubes. The valve i8 is operated responsive to..the level of water in the float chamber 69 to admit such quantity of unevaporated spray water as is required to maintain substantially a constant level, thereby providing the required amount of water to be circulated by the pump 6!. When the supply of unevaporated spray water or other supply of additional liquid is less than the capacity of the pump 6!, the valve 15 serves to prevent the entrance of air into the conduit 68, by closing in response to drop in level of water in the float chamber $1.

To the above described refrigerating apparatus, I supply the following control mechanism. Line conductors L1 and L2 provide a supply of electrical energy. A switch 82, preferably manually operated, is adapted to close a circuit 83 extending through the motor 2! which drives the ventilating fan l9. There is also interposed in the circuit 83 the contacts 8d of a thermostat 85, which is re- U sponsive to the termperature of water in the evaporator header I 3, and which is constructed to open the contacts 84 when the temperature within the evaporator increasesto a point where the air supplied to the enclosure l8 would be heated instead of cooled, which condition might occur if the ejector failed to establish ejecting action and permitted steam to flow into the evaporator. As will be apparent from the drawing, the circuit 83 extends from the line conductor L2 through the switch 82, the contacts 84 and the motor 28 to the line conductor L1.

There is also provided a two-pole main switch fit. This switch is adapted to render the refrigerating mechanism operable as long as it is closed and to render the apparatus inoperable when it is opened. It is also adapted to effect operation of the ventilating fan 89 as long as it is closed except when an excessively high temperature exists in the evaporator it. allel with the switch 82 and is thereby adapted to eflect operation of the ventilating fan i a whenever the switch 86 is closed. The other pole of the switch 86 connects the line conductor L2 to a conductor 811, through which current is supplied to the refrigerating apparatus. One terminal of the motor 63 is connected to the conductor 8'4! and the other terminal to the line conductor L1 so that the motor 63 drives the pumps til and We as long as the main switch 86 is closed. The solenoid 88 which operates the valve 28 to supply steam to the ejector 1'6 and the motor 3! which drives the fan 36 for circulating-air over the condenser are intended to be operated primarilyin response to demand for refrigeration, in this case in response to a predetermined maximum temperature in the enclosure l8. Accordingly, a thermostat 89 is subjected to the temperature of the air in the enclosure, as by locating the thermostat at a point at which the temperature is representative of the average temperaturein the enclosure. The thermostat is provided with contacts 9|, which are adapted to be closed when the temperature reaches a predetermined maximum temperature indicating a demand for cooling ac- One pole of this switch is in partion. Obviously, the thermostat 89 may be of any suitable type known in the art and may be adjustable to operate at different temperatures. There is also provided in parallel with the contacts 9! a set of contacts 193 actuated by a pressure-responsive element H16 in response to pressure in the conduit 62, the arrangement being such that the contacts 93 are opened when there is pressure in said conduit and closed in the absence ofv pressure therein. The purpose of this device is to admit steam to the ejector and condense the same in the condenser in order to provide the water necessary for operation of the apparatus, when there is not sufficient water, as will be further described here-- I may provide a relay 9% having contacts 91 in the circuit to the solenoid 83 and arranged to be closed by a solenoid 98 in the circuit to the motor 3? only when current is flowing to said motor.

The circuit for controlling operation of the condenser circulating fan includes the line conductor L2, one pole of the switch 86, the conductors 81 and 99, the contacts 95, the conductor l t l, the contacts 96 and 93 in parallel, a conductor nor, the solenoid 98, a conductor M3, the motor 3i, and the line conductor L1. The circuit for the solenoid 88 extends in common with the circuit for the motor 37 as far as the conductor E02,

then through the contacts 97!, a conductor BM, the solenoid 88, and a conductor W5 to the line conductor L1.

I prefer to control the air ejector in 'response to pressure within the conduit 62, for the reason that air leakage into the condensing space may take place through the pump 6i when the latter is not in operation. Accordingly, I arrange the pressure responsive element 5% to operate a valve Hill in the steam pipe 008 which supplies steam to the air ejector 35, said element being arranged to open said valve in response to pressure in the conduit 62 and to close said valve in the absence of pressure.

The operation of the above described apparatus is as follows: the fan l9 may be operated for ventilation of the closure it, without any cooling, by closing the switch 82, which closes the circuit Bate energize the motor 26. g

If cooling action is desired, the switch at is closed, which also closes the circuit 83 to energize the motor 28. Thus, the fan it operates to circulate air through the evaporator and to the enclosure [It during the full period that the switch 86 is closed to render the refrigerating apparatus operable, with the exception referred to when the temperature in the evaporator becomes too high, in which: case the thermostat opens its contacts 8 5 to terminate circulation of culated through the evaporator 10 by the pump" andspray water issupplied to -the condenserin the apparatus, the pump 6i fails to build up by the pump 6 I. As soon as pressure is developed in the conduit 62 by the pump 6i, the pressure responsive device I06 opens the valve 801 to supply steam to the air ejector 35, whereupon vacuum is established in the condensing space of the condenser. As soon as the necessary vacuum is established, the apparatus is ready for cooling action. At the moment that the switch 86 is closed, the contacts 93 will also be closed due to the absence of pressure in the conduit 62. Accordingly, the condenser fan 36 will be operated and steam will be momentarily admitted to the ejector 2 3. However, the pressure in the conduit 62 will be promptly established, whereupon the contacts 93 will be opened to discontinue operation of the fan 36 and admission of steam to the ejector 2 3, unless the thermostat 89 is. calling for cooling. 7

The apparatus now operates in response to demand for cooling within the enclosure 9. When the temperature in the enclosure is above a predetermined temperature, fthe thermostat t9 closes its contacts to 'eifect admission of steam to the ejector 26 and operation of the fan 35, whereupon the refrigerating apparatus operates in the manner above described to cool the air circulated over the tubes M by the fan 59. When the temperature in the enclosure has been brought to a sufiiciently low temperature, the thermostat '89 opens its contacts 9% to discontinue cooling action. Circulation of water through the evaporator and the supply of water perature of the water in the evaporator increases to a temperature above 40 F. I

Inasmuch as the present apparatus is adapted particularly to the cooling of railway passenger cars, the water may be drained from the apparatus when the car is subjected to cold weather, in order to prevent the possibility of freezing of the water and damage to the apparatus. The present apparatus is adapted to operate automatically to provide the necessary quantity of water upon the'switoh at being closed. As described, as soon as the switch 86 is closed, the pressure responsive device I06 closes the contacts 98 to eifect admission of steam to the ejector and operation of the fan 38- to efiect condensation of steam. If there is insufiicient water sufflcient pressure in the conduit 62, so that the pressure responsive element I06 maintains the contacts 93 closed. Consequently, admission of steam to the ejector and condensation thereof in the-condenser continues until there is sumcient water, at which time pressure will be built up in the conduit 62. The pressure-responsive element then opens the contacts 93, whereupon further condensation ceases unless the thermostat 89 is calling for cooling. The ejector 35 is also started to establish vacuum in the condenser, as already described.

In Fig. 3, I show a modified arrangement for preventing the circulation of heated air in the event of entry of motive fluid into the evaporator. This construction is shown as applied to a railof the aisaaio way passenger car. The evaporator it], which is connected to an ejector and constructed similarly to the first embodiment, is disposed-in a duct or passage Hi9 through which air is circulated by a fan I it. Air returned from the conditioned enclosure is admitted to the passage through an opening ii 2 and fresh air is admitted through an opening Ht into the left-hand end of the passage to be cooled by the evaporator It. An opening lid is also provided to admit air returned from the conditioned enclosure to the passage I09 between the evaporator an and the fan Mil. A damper H5, which may comprise a series of louvers or vanes, is provided in the passage I09 between the evaporator it and the opening Ht. This damper is adapted to be closed by a solenoid lit disposed in a circuit 88'. The circuit 83' is controlled by the contacts 84 of a thermostat 85, which is responsive to temperature in the evaporator it, similarly to the first embodiment.

In normal operation, the damper H is open, and return and fresh air is conveyed over the tubes of the evaporator iii to be cooled and then conveyed by the fan M0 to the space to be air conditioned. Additional air from the enclosure may also be admitted through the opening [it to provide the desired amount of ventilation. In the event that motive fluid for the ejector enters the evaporator it, the thermostat at closes the closed when the damper H6 is open, and vice versa. The advantage of the embodiment of Fig. 3 is that ventilation of the air conditioned space is maintained while the circulation of heated air is prevented.

From the above description, it will be seen that I have provided apparatus whereby circulation of air over the evaporator and to the enclosure to be cooled is discontinued in the event that relatively hot motive fluid enters the evaporator l0; wherein operation of theair removalmeans for the condenser'is normally initiated promptly after closing of the main switch; wherein the mechanism operates automatically to providethe nec-, essary water in case, the apparatus has been drained; and wherein the refrigerating action is discontinued temporarily in case of excessively cold temperature of the water in the evaporator.

While I have shownmy invention in several forms, it will be obvious to those skilled in the art that it is not'so limited, but is'susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be imposed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In vapor jet cooling apparatus, the combination of an evaporator, an ejector having nozzles adapted to be connected to a source of condensable motive fluid, a condenser for said ejector for condensing fluid discharged by said ejector, means for supplying the liquid required in the apparatus from the condensate from said condenser, and means operating automatically in response to deflciency of liquid in the apparatus for eflecting admission of motive fluid to said nozzles, notaraaaro withstanding absence of sufilcient vacuum in the condenser for cooling action, in order to provide the liquid required in the apparatus to initi= ate cooling action thereof,

2. In vapor jet cooling apparatus, the combination of an evaporator, an ejector having nozzles adapted to be connected to a source of condensable motive fluid, a condenser for condensing fluid discharged by said ejector, means for supplying the liquid required in the apparatus from the condensate from said condenser, control means for rendering the "apparatus operable or inoperable, and means effective, whenever said control means renders the apparatus operable and the quantity of liquid in the apparatus is insuficient for cooling action, and notwithstanding absence of sufllcient vacuum in the condenser for cooling action, to provide the required amount of liquid by condensing fluid from said motive fluid source.

3. In air cooling apparatus, the combination of a cooling element, means for circulating air in direct contact with said cooling element, and

means responsive to a predetermined maximum temperature of said cooling element to prevent operation of said air-circulating means.

4. In vapor jet refrigerating apparatus, the combination of means including an evaporating chamber for cooling air, means for circulating air in direct contact with said air-cooling means, an ejector for removing vapor from said evaporating chamber to effect cooling therein, and means responsive to a predetermined maximum temperature in said evaporating chamber for terminating operation of said air circulating means. I

5. In air cooling apparatus, the combination of a cooling element, means providing circulation of air in direct contact with said cooling element, and means responsive to a predetermined maximum temperature of said cooling element to'discontinue circulation of air in heat-exchanging relation with said cooling element.

6. In air cooling apparatus for an enclosure,

the combination of a cooling element, means for termined maximum temperature of said cooling element to discontinue circulation of air in heatexchanging relation with said cooling element while permitting circulation of air through said enclosure to continue.

7. In vapor jet cooling apparatus, the combination of an evaporator, an ejector having nozzles adapted to be connected to a source of condensablemotive fluid, a condenser for said ejector for condensing fluid discharged by said ejector, means for supplying the liquid required in the apparatus fromthe condensate from said condenser, and means operating automatically in response to deficiency of liquid in the system for efiecting admission of motive fluid to said nozzles in order to provide the liquid required in the apparatus to initiate cooling action thereof.

8. In vapor jet refrigerating apparatus, the combination of an evaporator, an ejcctorfor withdrawing vapor from the evaporator, a condenser for the ejector, cooling fluid circulating means for the condenser, a condensate removal pump for the condenser, a switch adapted in a first position to render the refrigerating apparatus operable and to effect continuous operation of the condensate removal pump and in a second position to render the refrigerating apparatus and condensate removal pumpinoperable, automatic means operable in response to cooling requirements, when said switch is in said first position and renders the apparatus operable, to effect admission of motive fluid to the ejector and to eiiect operation of said cooling fluid circulating means, and means operable automatically to efiect admission of motive fluid to the ejector and to effect operation of said cooling fluid circulating means in response to a predetermined minimum pressure of fluid developed by said condensate removal pump andindependently of the action of said automatic means, when said switch is in said first position to render the apparatus operable.

9. In vapor jet refrigerating apparatus, the combination of an evaporator, an ejector, a condenser, air removal means for the condenser, other means for removing condensate from the condenser, and means operable automatically upon effectiveness of the condensate removal means for efiecting operation of the air removal means.

10. In vapor jet refrigerating apparatus, the combination of an evaporator, an ejector, a condenser, a mechanical condensate removal pump having its inlet connected to the condensing space of the condenser for receiving condensate therefrom, and means responsive to pressure developed by said pump for automatically efi'ecting operation of said air removal means.

11. In vapor jet refrigerating apparatus, the combination of an evaporator, an ejector, a condenser, an ejector for removing air from the condenser, a mechanical condensate removal pump having its inlet connected to the condensing space of the condenser for receiving condensate therefrom, and means responsive to pressure developed by said pump for automatically control ling the supply of motivating fluid to said air removal ejector.

12. In air cooling apparatus, the combination of a refrigerant evaporator, means for removing vapor from said evaporator to efiect cooling by vaporization of liquid therein, means providing circulation of air in direct contact with said evaporator, and means responsive to a predetermined maximum temperature of said evaporator to discontinue circulation of air in contact with said evaporator.

13. In air cooling apparatus, the combination of an evaporator, a vapor motivated ejector for temperature of said evaporator to discontinue" circulation of air in contact with said evaporator.

14. In vapor jet refrigerating apparatus, the combination of an evaporator, a vapor motivated ejector connected thereto, a condenser for condensing the fluid exhausted from said ejector, a pump having its inlet connected to said condenser for removing condensate therefrom, control means for rendering said ejector operable or inoperable and for efiecting operation of said pump simultaneously with rendering said ejector operable, and means operable automatically in. response to a predetermined minimum pressure developed by said pump for effecting admission of motive fluid to said ejector to provide liquid by condensation of motive fluid in said condenser.

ERNEST F. MILLER.

DISCLAIMER 2,122,210.Ernest F. Miller, Prospect Park, Pa. COOLING APPARATUS. Patent dated June 28, 1938. Disclaimer filed August 3, 1939, by the assignee,

Westinghouse Electric ct Manufacturing Company. Hereby enters this disclaimer to claims 3, 5, and 12 in said specification.

[Ofiicial Gazette August 22, 1.939.]

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