US2402802A - Refrigerating apparatus - Google Patents

Description

June 25,1946. I F, Y, CARTER 2,402,802

REFRIGERATING APPARATUS Filed' Feb 17, 1944 FIG. l

INVENTOR M A4 M Y A ATTORNEY Patented June 25, 1946 UNITED STATES 2,402,802 REFRIGERATING APPARATUS Franklyn Y. Carter, Detroit, Mich., asslgnor to Detroit Lubricator Company, Detroit, Mich., a corporation of Michigan Application February 1'1, 1944, Serial No. 522,741

1 Claim. 1

This invention relates to new and useful improvements in refrigerating apparatus and more particularly to means for supplying refrigerant medium to a multiple evaporator.

In order that a plurality of evaporating elements or a multi-pass evaporator, supplied with refrigerant medium from a single condenser in a refrigerating system, may be supplied with equal quantities of refrigerant medium, a header or distributor member for dividing the flow of the refrigerant medium must be employed. The'volatilization or vaporization of the refrigerant medium on the outlet side of the expansion valve.

normally results in the gasifying of the refrigerv ant medium on the inlet side of the distributing member and, accordingly, various kinds of distributingdevices have been employed for equalizing the flow of liquid refrigerant medium through the distributing member. Such devices have either failed to provide equal flow of refrigerant medium liquid per unit of time or have been so ineflicient in distributing the liquid that there has been non-uniformity in the work done by the various evaporator elements or passes of a multi-pass evaporator.

Accordingly, it is an object of this invention to provide an apparatus in which each of the evaporator elements of a multiple system are supplied with equal quantities of liquid refrigerant medium per unit of time for equal heat exchange evaporator elements or with quantities proportional to the heat exchange surface of the elementa.

Other objects and advantages of the invention will be apparent from the following specification and the novelty of the invention will be particularly pointed out and distinctly claimed.

In the accompanying drawing to be taken as a part of this specification there are fully and clearly illustrated several preferred embodiments of the invention, in which drawing:

Figure l is a diagrammatic view of a refrigerating apparatus or system showing one form or arrangement for accomplishing the invention;

Fig. 2 is a detail view in perspective of a distributing member forming part of the invention; Fig. 3 is a diagrammatic view of part of a refrigerating apparatus or system showing another form of apparatus for accomplishing the invention, and

Fig. 4 is a diagrammatic view of part of a refrlgerati'ng apparatus or system showing another arrangement for accomplishing the invention.

Referring to the drawing, Fig. 1, by characters of reference, the numeral I. designates a compressor driven by any motive power means, such as an electric motor (not shown) and which may be controlled in any of the usual ways as by a return or suction line pressure switch. The high pressure side of the compressor is, connected to and discharges into a conduit or pipe 2 which feeds into a condenser 3 which is connected by a pipe or conduit 4 to the usual receiver 5. The

refrigerant medium high side liquid line or coni s duit 6 connects from the receiver below the liquid level therein and leads to the inlet I of a thermostatically controlled refrigerant expansion valve 8 which may be of the type and construction disclosed in my copending application Serial No. 510,328 filed November 15, 1943 for Refrigerant distributing means. The outlet 8 of the expansion valve is connected to a distributing member H), see Fig. 2, which is clamped to the expansion valve body by an annular clamping member H which seats against the flange l2 on the member II). The outlet passage of the expansion valve opens into a pressure chamber IS in the member Hi. The chamber I! has a plurality of restricted outlet ports or passageways 2 ll, equal in number of the number of passes or evaporator elements to be supplied with refrigerant medium. The passageways H are connected by conduits l5 of restricted internal bore and preferably all of the same length and internal bore, one to each of the evaporator elements or passes it which are provided with common or interconductlng heat exchange fins or plates i1 connecting the tubes or passes of the evaporator. The tubes or elements it connect into a suction medium return or suction line I 9 connects into the suction or inlet side of the compressor I.

The valve 8 is thermostatically controlled by a thermostatic actuator 20 having the usual pressure responsive movable wall member operable to move the valve member toward open position in accordance with a desired superheat setting of the valve and in response to the temperature of a volatile liquid in the bulb element 2| clamped n in heat exchange relation to the return line I! and connected by the usual capillary tube 22 to the expansible chamber of the actuator 2|. The valve 8 is also controlled by the back pressure of the refrigerant medium, as is well understood in the art, by means of an equalizer tube or connection 23 connected at one end into the chamber of a pressure responsive member in the valve tending on pressure increase to move the valve member toward closed position, the tube 23 being connected at its other end into the system low side and, for example, into one of the liquid refrigerant medium feeding tubes II. The heat exchange fins or plates I1 are preferably pro vided'with extended portions 24 which are apertured to receive a portion 25 of the liquid refrigerant feed line or conduit 8 which is intimately bonded to and for heat exchange relation with the tin portions 24. Accordingly, the liquid refrigerant medium supplied to the valve I will be cooled in the conduit portion 25 and the exor return line header l8 from which a refrigerant Monaco -within or in intimate heat exchange relation with the suction line header I. so that the liquid medium fed to the expansion valve, then it will be impossible to prevent flashing or vaporizing of the refrigerant medium in the distributing member chamber It. For example, if the refrigerant medium supplied to the valve is say at a temperature of 100 F. which, for Freon, would -mean a gas pressure of 117 lbs. per square inch, then,'because of the necessity to have a pressure drop in order to have refrigerant medium through the valve 0, the pressure of the refrigerant medium in the chamber I! would have to be lower than 117 lbs. per squareinch and, accordingly, the refrigerant medium in the chamber It would be at a temperature above it saturation temperature and accordingly gasify or vaporize, with the result of unequal feeding of the liquid portion of the refrigerant medium through the ports It to the evaporator passes. Therefore, by this invention the refrigerant medium is cooled in the liquid line portion 25 to a temperature inlow that which will correspond to the intermediate pressurein the chamber I3 and, accordingly, there will be no flash gas or vaporization of the refrigerant medium which would upset the equal feeding of liquid through the ports It. For example. and solely by way of illustration, if there is a head pressure of say 117 lbs. per square inch with a compressor creating a suction pressure of 40 lbs. per square inch, and it is desired to have. a. pressure drop through the distributor member ports or passageways H and the tubes II at a pressure drop across the valve 8 of say q 47 lbs. per square inch in order to have feeding of the necessary quantity of liquid refrigerant medium to provide the desired evaporator capacity, then there will be a pressure in the chamher I! of 70 lbs. per square inch; Accordingly,

since the temperature of the refrigerant medium in the chamber it at which boiling will occur will be for Freon at 70 lbs. per square inch, a temperature of 70 F., then the heat abstracted from the liquid refrigerant medium in theline portion 25 must be sufficient to cool the liquid refrigerant medium to a temperature below the saturation temperature in the chamber it, say for example to a temperature of 65 F. as a margin of safety. The number and extent of the fin portions 25 in heat exchange relation to the port 24 and the number of passes of the portion 2! through the fin portions will of course vary in accordance with the temperature of the high side liquid refrigerant medium in the conduit 6, the temperature of the evaporator, and the saturation temperature in the distributing member chamber it, but can be readily ascertained when these variables are known.

Referring to Fig. 3, the reference characters applied to Fig; l, but with the suffix a, designate like parts in this Fig. 3. Instead of having the heat exchange fins or plates ll' extended to provide the portions 2!, the high side liquid refrigerant line I is provided with a heat exchange coil or conduit portion II which i positioned refrigerant medium in the liquid line i is cooled by the refrigerant medium at the outlet end D tion of the evaporator. This system or apparatus functions in the same manner as that of Fig. 1 and the illustrations above set forth ar equally applicable here, it being apparent that the extent of the tubing or c011 ll must be sufficient to cool the liquid refrigerant medium below the saturation temperature which obtains in the distributing member chamber II.

Referring to Fig. 4, the reference characters applied to Fig. 1 but with the suffix b designate .like parts'in this figure and therefore the description of the same will be apparent from the description of Fig. 1. In this Fig. 4, the high side liquid refrigerant line or conduit I" has a coil or heat exchange portion 40 which is in intimate heat exchange relation with an evaporator ll which may be of tubular form to surround the liquid line portion 40 passing longitudinally therethroush. The evaporator ll ma be supplied with refrigerant medium .by a pipe or conduit 42 connected into the liquid line or conduit 8" and having intercalated therein for controlling flow of refrigerant therethrough to the evaporator II a thermostatic expansion valve ll controlled by back pressure and by temperature from a bulb element 44 similarly to the control of the valve 8* to control the flow of refrigerant medium. A suction or return line pipe or conduit 45 leads from the'evaporator 4| and connects into a suction line or conduit I! on the outlet side of ,the bulb element 2| of the main evaporator controlling. expansion valve i". The operation of the apparatus of this Fig. 4 will be apparent from the foregoing description of Fig. l but has the advantage that the subcooling of the liquid refrigerant medium to be supplied to the valve 8 can be regulated or controlled without necessitating change in the construction and extent of heat exchange surface as would be necessary in Figs. 1 and 3.

Having thus described my invention, what i claimed and is desired to be secured by Letters Patent of the United States is:

A refrigerating apparatus comprising a multipass evaporator, a refrigerant medium distributing member having a chamber and a plurality of restricted outlet passageways leading therefrom, a plurality of distributing conduit members for connecting the passageways to the evaporator passes and connected one to each of said passageways and passes, an expansion valve controlling the supply of refrigerant medium to said distributing member chamber, said outlet passageways being o restricted as to create in said chamber a predetermined refrigerant medium pressure. a liquid refrigerant medium conduit spaced from said evaporator passes and leading to the inlet of said expansion valve, and a plurality of heat exchange fins projecting from said liquid conduit and having apertures tightly receiving said evaporator passes so as to cool the refrigerant medium to be supplied to said chamber to a temperature such that the refrigerant medium will not vaporize at the predetermined pressure'in said chamber.

I -FRANKLYN Y. CARTER.

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