US2242334A - Refrigerating system - Google Patents

Description

May, 20, 1941. D. D. WILE 2,242,334

REFRIGERATING SYSTEM Filed March :50, 1958 M ATTORNEY Patented May 20, 1941 UNITED STATES PATENT OFFICE REFRIGEBATING SYSTEM Daniel D. Wile, Utica, N. Y., assignor to Detroit Lubricator Company, Detroit, Mich, a corporation of Michigan Application March 30,19 8, Serial No. 198,926

14 Claims. (Cl. 62-2) My invention relates generally to refrigerating systems and more particularly to those using a thermostatic expansion valve. K

An object of my invention is to provide means for controlling the flow of a refrigerating medium I refrigerating mechanism.

Another object is to furnish means to alleviate the difliculties caused by the warmingof the flow controlling responsive means relative to the evaporator. V r

The invention consists in the improved construction and combinationlof parts, to be-inore fully described hereinafter and the novelty of which will beparticularly pointed out and distlnctly claimed. a

In the accompanying drawing, to be taken as a part of this specification, I have fully and clearly illustrated my invention, in which drawing Figure 1 shows a schematic illustration of a refrigerating system having an air cooling coil or evaporator within an air duct and embodying my invention;

Fig. 2 is a view similar to Fig. 1 but showing a will be in heat exchange relation with the evaporator l. The evaporator I has an outlet conduit or suction line 9 leading to a compressor III which is connected by means of a conduit II to the condenser 4 to form a complete refrigerating system, within which system therefrigerant or performing means is confined.

Leading from the power element lZ of the thermostatic expansion valve I there is a fluid pressure bonve' ng conduit l3 having one end communicative y connected to the power element l2. The opposite end of the conduit H, which is located within the air duct 8 adjacent the evaporator I, has an actuating means or chambered feeler bulb l4 communicatively connected thereto. A second fluid pressure conveying conduit l5 has one end communicatively connected to the power element l2 and has at its opposite end an actuating means or chambered feeler bulb l6 operatively connected thereto. A sealed, closed,

interconnected control system is thereby formed different means for controlling the refrigerant medium flow, and

Fig. 3 shows schematically one form of my invention as used in connection with a brine tank cooler.

Referring to the drawing by characters of reference the numeral l designates generally a controlling means which in this case is shown as' a thermostatic expansion valve having its inlet or liquid port 2 connected by means of a conduit 3 to a condenser 4. The outlet or low pressure side 5 of the expansion valve l is connected by means of a conduit 6 to an evaporator or low side element I, preferably of the coil type and located within a cooling chamber which is an air duct 8 so that the air or controllable means which flows therethrough and discharges into the space or room I 51. e. flow from left to right facing Fig. 1,

of the members I2 to IE each inclusive, and is charged with a predetermined amount of a tem: perature sensitive, volatile fluid of a quantity and of such proportions that the entire fluid in a liquid state may be contained in either of the two feeler bulbs It or 16. This allows the fluid pressure in the control system to be controlled solely by the bulb which is at the lower temperature. The feeler bulb I4 is positioned within the air duct 8 with the tube l3 leading from its upper end, and is preferably in the untempered air stream, 1. e. on the inlet side of evaporator l, in good heat exchange relation with the air. The

' feeler bulb i6 is secured in good heat exchange relation to the outlet conduit 9 adjacent the evaporator so that the bulb l6 will be accurately responsive to the temperature of the refrigerant adjacent the evaporator outlet, but the bulb is preferably external of the duct 8 so that it can be removed without extensive alterations to the duct.

In Fig. 2 parts defined with respect to Fig. 1 and similar thereto are designated by like numerals. communicatively connected to the power element I 2 there is one end of a fiuid pressure conveying conduit 20 having its other end connected to one end of a feeler bulb 2i. The feeler 'bulb 2| is secured in good heat exchange relation to the suction or return line 9 adjacent to the outlet of evaporator l but external of the air duct conveying conduit 22. The other or opposite end of the conduit 22 is communicatively connected to a feeler bulb 22-which is located in the inlet air stream to the evaporator I within the air duct 8. The members [2, 20, 2|, 22 and 23 in this modification form a sealed control system which is charged with a temperature sensitive, volatile fluid in a manner similar to that of Fig. 1.

The parts heretofore defined in connection with Figs. 1 and 2 are designated by like numerals in Fig. 3. The outlet of the thermostatic expansion valve l is connected by means of the conduit 6 to an expansion coil 40 located within a liquid receptacle. such as a brine tank or cooling chamber generally designated at ll. The outlet of the coil 40 is connected to the outlet conduit 9 which leads to the compressor l0, and the inlet 2 to valve! is connected to the condenser l by conduit 3, as in Figs. 1 and 2. The temperature responsive bulb 2|, connected by conduit to the expansion valve power element I2, is fastened to the suction line conduit 9 adjacent its outlet from tank ll and in good heat exchange relation thereto. The bulb 23. in communication with bulb 2| by conduit 22, is inserted into the brine tank 4|, as for example by means of a sealed tubular member or well 42, and is in good heat exchange relation with the liquid or brine .42 within the brine tank 4|.

The operation of the apparatus of Fig. 1 is as follows: High pressure liquid refrigerant flows from the condenser 4 through the liquid line 3 and into the thermostatic expansion valvel by means of the inlet 2. The refrigerant is me- .tered by the valve l and the metered refrigerant, which is substantiallv a liquid, leaves the valve through outlet 5 and passes through conduit 6 into the evaporators 'I where it is completely vaporized by the heat extracted from the air which flows through the air duct 8. The gaseous refrigerant then passes through the outlet or suction line conduit 9 to the compressor II which maintains a redetermined pressure in the suction line 9. The gaseous refrigerant is compressed by the compressor III to raise the temperature of the heat contained in the low pressure vapor, and the high pressure vapor is exhausted through conduit ll into the condenser 4. Heat is dissipated by the condenser l to liquify the refrigerant.

The operation of the valve I will be controlled by the bulb M or the bulb lflwhichever has the lower temperature. and this is possible by predetermining the capacity of and the quantity of volatile liquid charge in the feeler bulb or control system such that all of the temperature sensitive or responsive fluid therein, which is in the liquid stage. may be at all times contained within one or the other of the feeler bulbs or elements. The pressure within the control system will be determined by the bulb having the lower temperature since there is no volatile liquid in the other bulb. and the bulb of lower temperature will assume control over the thermostatic expansion valve I. The feeler bulb l6, located in h at exchange relation with the' suc-- tion line 9, governs the quantity of refrigerant supplied by the expansion valve l to the evaporator I during the time that the condensing unit is running and the evaporator is cooling the air flowing through the duct 8. The quantity of refrigerant supplied iscontrolled in such a manner by the bulb it that no liquid. refrigerant escapes throueh the suction line 9 to the compressor I0. When the air within the air duct 8 becomes colder than the temperature for which the evaporator is set to operate, ancithe comevaporator below duct air temperature.

pressor Ill is no longer operating, the bulb It will warm up above the temperature of the bulb l4 and the bulb ll will therefore assume control and will close the expansion valve to further flow of refrigerant. The valve I in operation tends to maintain constant the relationship of the liquid refrigerant temperature in the evaporator to the temperature of the controlling bulb which is maintained slightly warmer than the refrigerant. when the air entering the evaporator l is as cold or colder than the temperature at which the evaporator is set to operate, the compressor I will not need to' be run so as to cool theevaporator, thereby to cool theair passing through it. The bulb I6 which is located outside of the duct 8 and in a warmer place than bulb ll, will tend to warm up due to the temperature of the surrounding medium. The bulb 14 within the duct 8 will be maintained at the duct air temperature, and the liquid portion of the charge which was in bulb It will distill over to bulb I4 because of its lower temperature. The pressure in the control system will then be controlled by the temperature at this bulb ll. As the evaporator, and consequently the refrigerant therein, will be at the temperature of bulb I. there will be no difference of temperature between the bulb l4 and the refrigerant so that the back pressure of the refrigerant will hold the valve closed to further flow of refrigerant. When the duct air temperature warms up, and the compressor is again started, then the vaporizing refrigerant will cool the The suction line Sand bulb IE will be cooled below duct air temperature by the flow of cool refrigerant vapor through the line 9 and the control will be transferred from bulb I4 to bulb I6 for normal operation.

The operation of the apparatus of Fig. 2 is substantially the same as that of Fig. 1, but the bulbs' here designated 2| and 23 are arranged in series and have only one conduit leading to the power element l2 of the expansion valve I so that when bulb 2| is the warmer, it serves merely as a part of the pressure conveying conduit for bulb 23. Thepressure in this control system is likewise .controlled by whichever of the bulbs is at the lower temperature, and either may contain all of the fluid which is in the liquid phase at any one time. The construction of this control system eliminates separate pressure conveying tubes or conduits leading from the valve power element and consequently is less expensive and requires in the majority of cases less length of tubing and is more convenient in installation.

The operation of the apparatus of Fig. 3 is similar to that of Figs. 1 and 2 in that the flow of refrigerant through the expansion valve. l is controlled by the bulb having the lower temperature. During the "off period of the compressor, which controls the refrigerating effect of the air cooling system, the suction line 9 will tend to warm up more rapidly than the brine 43 and evaporator coil 4. within the brine tank 4|, due to the larger mass of the brine. If the OH period of the compressor is sufllciently long, the bulb '2l will become warmer than the bulb 23 and transfer the control of the expansion valve to the bulb 23 which will close-on the expansion valve to' further flow of refrigerant and prevent the coil ll from becoming filled with liquid re- Patent of the United States is:

1. In a refrigerating system including a cooling chamber having a refrigerant evaporator with a refrigerant return line, a valve for controlling the supply of refrigerant to the evaporator, power means for actuating said valve, and a pair of temperature responsive elements communicatively connected to said power means, one of said elements being subject to the temperature of the refrigerant return line, the other of said elements being subject to temperature in the cooling chamber, said elements and said means being charged with a predetermined quantity of condensible temperature responsive fluid which is volumetrically condensible for complete reception in one or the other of said elements so that the element at the lower temperature will have exclusive control of said valve.

2. In a refrigerating system including a cooling chamber having a refrigerant evaporator with a refrigerant return line, a valve for controlling the supply of refrigerant to the evaporator, power means for actuating said valve, a temperature responsive element, and a second temperature responsive element, said first-named responsive element being communicatively connected through said second-named responsive element to said power means, one of said elements being subject to the temperature of the refrigerant return line adjacent the evaporator, the other of said elements being subject to temperature in the cooling chamber, said elements and said means being charged with a predetermined quantity of condensible temperature responsive fluid which is volumetrically condensible for complete reception in one or the other of said elements so that the element at the. lower temperature will haveexclusive control of said valve. 3. In a refrigerating system including a cooling chamber having a refrigerant evaporator with a refrigerant return line, a valve for controlling the supply of refrigerant to the evaporator, power means for actuating said valve, a temperature responsive element, conduit means connecting said responsive element to said power means, a second temperature responsive element, and a second conduit means connecting said second-named responsive element to said power means, one of said elements being subject to the temperature of the refrigerant return line, the other of said elements being subject to temperature in the cooling chamber, said elements and said means being charged with a predetermined quantity of condensible temperature responsive fluid which is volumetrically condensible for complete reception in one or the other of said elements so that the element at the lower temperature will have exclusive control of said valve. 4. In a refrigerating system including an air supply duct having a refrigerated air cooling coil with a refrigerant flow controlling means, power means operable to control said flow controlling means, conduit means connecting said controlling means to the cooling coil so that refrigerant can flow from said controlling means to the cooling means, an outlet conduit from the cooling means, v temperature responsive means subject to the temperature of said outlet conduit, means connecting said responsive means and said power means in operative relation, temperature responsive means subject to the temperature of the air in the supply duct, conduit means connecting said second-named responsive means and said power means, said responsive means, said conduit means and said power means defining a closed system, and a condensible temperature responsive fluid in said system and in such proportions that said fluid in the liquid phase can be at all times contained in either of said responsive means so that the responsive means which is at the lower temperature will assume absolute control over said power means.

5. A cooling system comprising a cooling coil for a liquifiable refrigerant medium, means to supply refrigerant medium to said coil, a valve controlling admission of the refrigerant medium to said coil, temperature responsive means regulating the operation of said valve, and means operable solely when the temperature of a medium to be cooled by said coil is below-the temperature of said temperature responsive means to deprive said, responsive means of any effect to influence the operation of said valve.

6. A cooling system comprising a cooling coil for a liquifiable refrigerant medium, means to supply refrigerant medium to said coil, a valve controlling admission of the refrigerant medium to said coil, an outlet conduit leading from said coil, temperature responsive means acting in accordance with the temperature of the refrigerant medium in said conduit and regulating the operation of said valve, and automatically acting temperature responsive means operable solely when the temperature of a medium to be cooled by said coil is below the temperature of said temperature responsive means to deprive said responsive means of any eifect to influence the operation of said valve.

'7. A cooling system comprising acoolin coil for a liquifiable refrigerant medium, means to supply refrigerant medium to said coil, a valve controlling admission of the refrigerant medium to said coil, temperature responsive volatile liquid containing means regulating the operation of said valve, and a chambered element communicating with and having a volumetric capacity sufllcient to receive the liquid in said responsive means so that said responsive means is deprived of control of said valve when the temperature of a medium to be'cooled by said coil is below the temperature of said temperature responsive means.

8. A coolingsystem comprising a cooling coil for a liquifiable refrigerant medium, means to supply refrigerant medium to said coil, a valve controlling admission of the refrigerant mediumto-said coil, temperature responsive means regulating said valve thereby to control the admission of. refrigerant to said coil, and means operable solely when the temperature of a medium to be cooled by said coil is below the temperature of said temperature responsive means to deprive said responsive means of any effect to influence the admission of refrigerant to said coil.

9. A cooling system comprising a cooling coil for a liquifiable refrigerant medium, means to supply refrigerant medium to said coil, a valve controlling admission of the refrigerant medium to said coil, temperature responsive volatile liquid containing means regulating the operation of said coil, and a chambered element communicating with and having a volumetric capacity sufllcient to receive the liquid in said responsive means so that said responsive means is deprived of-control of said valve when the temperature of a medium to be cooled by said coil is below the temperature of said temperature responsive means.

10. In a refrigerating system includin a cooling chamber having a refrigerant evaporator with a refrigerant return line, a valve for controlling the supply of refrigerant to the evaporator, power means for controlling said valve thereby to regu. late the admission of refrigerant to the evaporator, a temperature responsive element, and a second temperature responsive element, said firstnamed responsive element being communicatively connected with said second-named responsive element and operable to control said power means, one of said elements being subject to the temperature of the refrigerant in the return line, the other of said elements being subject to temperature in the cooling chamber, said elements and said means being charged with a predetermined quantity of condensible temperature. responsive fluid which is volumetrically condensible for complete reception in one or the other of said elements so that the element at the lower temperature will have exclusive control of said valve.

11. In a refrigerating system for an enclosed space having duct means for supplying air thereto, evaporating means within the duct means and positioned in the air stream, means to convey refrigerant to said evaporating means, means for conveying the refrigerant from said evaporating means, a refrigerant controlling means in said first-named conveying means to control the flow of the refrigerant to said evaporating means, temperature responsive means secured to and responsive to the temperature of said secondnamed conveying means, and a second temperature responsive means responsive to the temperature of the air in the duct means, said firstnamed and said second-named responsive means being so interrelated that when said secondnamed responsive means is at a lower tempera ture than said first-named means said secondnamed responsive means will assume complete perature of the inlet air to said evaporating means. said first-named and said second-named responsive means being so interrelated that when said second-named responsive means is at a lower temperature than said first-named means said second-named responsive mean. will asume complete control of said controlling means to prevent excess refrigerant from entering said evaporating means.

13. In a refrigerating system, an air supplying duct having an inlet and an outlet, evaporating means in said duct intermediate said inlet and said outlet, and a. thermostatically operated valve comprising a first and a second temperature sensitive element, a power element and conduit means interconnecting said elements to form a sealed system, said valve being positioned external of said duct and operatively connected to said evaporating means and operable to control the flow of refrigerant to said evaporating means, said evaporating means having an. outlet conduit means for conveying the refrigerant therefrom, said conduit means having a portion external of said duct, said first temperature sensitive element being secured to and in heat exchange relation with said portion, said second temperature sensitive element being positioned control of said controlling means to prevent excess refrigerant from entering said evaporating means.

12. In a refrigerating system for an enclosed space having duct means for supplying air thereto, evaporating means within the duct means and positioned in and transversely to the air stream, means to convey refrigerantto said evaporating means, means for conveying the refrigerant from said evaporating means, a refrigerant controlling means in said first-named conveying means to control the flow of the refrigerant to said evaporating means, temperature responsive means secured toand responsive to the temperature of -said second-named conveying means, and a second temperature responsive means positioned within the duct means and responsive to the temwithin said duct and sensitive to the temperature either of said sensitive elements so that the sen-v sitive element which is at the lower temperature willassume control of thepressure in said system.

14. In a heat transfer apparatus utilizing a heat transfer fluid for modifying the temperature of an air stream which is supplied to a tempered space, a controlling means for regulating the flow of the transfer fluid, an actuating means responsive to the temperature of the transfer fluid and operable to control said controlling means, an actuating means responsive to the temperature of the air stream and operable to control said controlling means, conduit means, connecting said first-named actuating means said second-named actuating means and said controlling means into .an interconnected system, said system containing a volatile temperature responsive fluid in such proportions relative to the volumetric capacity of said system that the quantity of fluid which is in the liquid phase can at all times be contained in either of said actuating means so that the one of said actuating means which is at the lower temperature will assume control over said controlling means.

DANIEL D. WILE.

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