US2636358A

US2636358A - Plural expansion refrigeration system

Info

Publication number: US2636358A
Application number: US115684A
Authority: US
Inventors: Homer T Chappelle
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-09-14
Filing date: 1949-09-14
Publication date: 1953-04-28
Anticipated expiration: 1970-04-28

Description

April 28, 1953 H. T. CHAPPELLE PLURAL EXPANSION REFRIGERATION SYSTEM FIG. 3

Filed Sept. lfl, 1949 INVENTOR. H. T. CHAPPELLE ilVilllill AT TORNEY Patented Apr. 28, 195 3 UNITED STATES PATENT OFFICE PLURAL EXPANSION REFRIGERATION SYSTEM This invention relates to refrigeration and more particularly to an improved system including a novel evaporator or heat absorbing means by the use of which improved efificiency may be obtained.

It is an object of the present invention to provide a refrigeration system having improved operating characteristics in which the evaporator is of novel construction by means of which improved efilciency may be obtained.

A further object of the invention is to provide an improved refrigeration system employing novel operating characteristics and improved evaporator construction in which a refrigerant i used which is particularly designed for use with the system embodying the present invention.

These and other objects of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a diagrammatic layout of one embodiment of the invention;

Fig. 2, a section on the line 2-2 of Fig. 1; and

Fig. 3, a section on the line 3-3 of Fig. 2.

Referring to the drawings the system includes a compressor ID for delivering compressed refrigerant into a discharge line II to be received in a condenser I2. From the condenser the liquid refrigerant passes through line I3 into a receiver l4. From the receiver the refrigerant passes through line l5 having a control valve [6 to an expansion valve I! just before entry into an evaporator 18. From the evaporator a suction line 32 leads back to the compressor 10.

The evaporator consists of a plurality of pairs of tubes I9, 20, I9, 20, etc., two pairs being shown for convenience. It is understood, however, that the invention contemplates the use of a multiplicity of pairs depending upon the capacity of the particular unit. The tubes are connected in series so that the refrigerant fiows through each of the tubes individually.

From the expansion valve I! the refrigerant flows into the tube l9, through the tube, and out itsopposite end into the elbow 22 which feeds into a header tube 23. The header tube is disposed transversely of and adjacent the ends of the next pair of tubes I9, 20. From the other end of the header tube an elbow 24 is connected substantially axiallyof the tube ,20 to a small orifice nozzle 25 positioned within the tube 20. Therefrig'erant then flow through nozzle 25 into the tube 20 and at its far end out through a tube p 26 and into the tube [9' through a small orifice nozzle 21 positioned axially of the tube.

At the opposite end of the tube IS the refrigerant is discharged through the elbow 28 into a header 28 from whence it passes through an elbow 38 into the tube 20 by means of a small orifice nozzle 3|. At the far end of the tube 20 the refrigerant is discharged into the suction line 32 to the compressor.

The ends of the tubes are provided with jackets 35 and 3B which extend for a small distance from each end of the tube and include the connections at the ends of the tubes. The joints between the jackets and the tubes and the connections are sealed in order that the jackets may be evacuated. Suitable insulation may be provided, if desired,

to reduce the transfer of heat from the jacket to the tubes by conduction. For the purposes of evacuation of the jacket, lines 3! and 38 are connected to the

jackets

35 and 36 respectively and are joined at a T 39 to a connection 40 provided with a check valve 4| which is placed in the suction line 32. It will be apparent that during the operation of the compressor the

jackets

35 and 36 will be under a vacuum corresponding approximately to the suction pressure of the compressor.

Although other refrigerants may be employed, a mixture consisting of carbon tetrachloride, anhydrous methylalcohol, and ethylene dichloride in the proportion of 20, 60, and 20 by volume respectively is preferred. This mixture is resistant to fire and has a boiling point of approximately 117 F. at atmospheric pressure.

In the operation of the device, the compressor discharges compressed refrigerant to the condenser at a relatively low pressure, which may be on the order of about zero gage. From the condenser the liquid refrigerant drains to the receiver and thence through the line It to the expansion valve ll. After passing through the expansion valve the refrigerant goes into the tube 20.

In passing through the expansion valve the pressure is reduced to about 12 Hg vacuum under normal operating conditions, the refrigerant being partially gasified in going through the tube 19. At the end of the tube the mixture of gas and liquid refrigerant passes out of the tube through the elbow 22.

The ends of the tubes i9, 26, i9 and 20, etc, the elbow connections and the

header tubes

23 and 24 are confined within the jacket 36.

As the mixture of liquid and'gaseous refrigerant passes from the endof the tube through the elbow 22 it drains into the header 23 which collects the mixture prior to its passage into the next tube. The header may be disposed adjacent or in contact with the next pair of tubes, and

subjected to the temperature prevailing in those tubes. Inasmuch as the refrigerant entering each tube passes through a pressure-reducing nozzle, it follows that correspondingly lower temperatures are attained in the succeeding cylinders comprising the evaporator. It is apparent therefore that heat exchange may take place under these circumstances between the refrigerant passing through a given header and that in the next succeeding pair of cylinders.

From the header the mixture fiows upwardly into the elbow 24 and into the nozzle 25 where it is expanded into the tube 26. As a result of the expansion the mixture undergoes a drop in pressure and passes through the tube 28 absorbing heat as it goes.

The refrigerant then passes through the remaining tubes and their nozzles and out of the last tube 2d into the suction line 32. In order that the system operate efiiciently the suction in the line 32 should be on the order of approximately 19 Hg vacuum but this may be varied to conform to the characteristics or the particular refrigerant employed.

By reason of the novel construction and arrangement of the evaporator, including the tubes having their ends confined in the jacket under vacuum, the arrangement of the headers, the refrigerant employed, and the order of vacuum under which the system operates, an improved efiiciency is attained so that a greater output per unit of input is obtainable than with conventional systems. Furthermore, the jackets are provided With efiective insulation at low cost due to the utilization of the compressor for the production of the vacuum therein.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawings and described in the specification but only as indicated in the appended claims.

What is claimed is:

1. An evaporator for a refrigeration system comprising a plurality of pairs of elongated cy1- inders including a last pair, one end of each cylinder providing an intake and the other end a discharge for the particular cylinder, the discharge end of the first cylinder of each pair except said last pair being connected to a cylindrical header disposed transversely of and adjacent the ends of the next pair of cylinders, a connection extending from the header to a nozzle disposed substantially axially of and extending into the intake end of the second cylinder of the pair, a connection from the discharge end of the second cylinder of the pair to a nozzle extending into the intake end of the first cylinder of the next pair, the connection from the discharge end of the second cylinder of the last pair being provided for connection to a compressor suction line, and a connection from the discharge end of the first cylinder of the last pair to a nozzle disposed substantially axially of and extending into the intake end of the second cylinder of the pair.

2. In a refrigeration system, a compressor having a suction line, an evaporator comprising a plurality of pairs of elongated cylinders connected in series, a first cylinder of each pair being connected by means of an elbow extending from the lower portion of its discharge end to a cylindrical header disposed transversely of and adjacent the extremities of the cylinders, an elbow extending from the header to a nozzle disposed substantially axially of and extending into the second cylinder in the pair, connections being provided to connect the second cylinder of a pair to the first cylinder of the next pair, a jacket housing the ends of the connections at the ends of the cylinders, and means for evacuating substantially all of the air from the jackets in order to produce a substantial vacuum therein.

3. In a refrigeration system, a compressor having a suction line, an evaporator comprising a plurality of pairs of elongated cylinders connected in series, a first cylinder of each pair being connected to a cylindrical header disposed transversely of and adjacent the extremities of the cylinders, means connecting the header to a nozzle extending into the second cylinder in the pair, connections being provided to connect the second cylinder of a pair to the first cylinder of the next pair, a, jacket housing the ends of the connections at the ends or the cylinders, and means for evacuating substantially all of the air from the jackets in order to produce a substantial vacuum therein.

a. The structure of claim 3, the last means comprising connections to the suction line of the compressor.

5. A low pressure refrigeration system comprising pump means capable of producing a high order of vacuum; a condenser connected to the pump means; a receiver connected to the condenser; an expansion valve connected to the receiver; an evaporator connected to the expansion valve, the evaporator comprising a plurality of pairs of elongated cylindrical tubes arranged in parallel, connections at the ends of the tubes providing for series flow through the tubes, the connections for a preceding pair being in proximity to a succeeding pair,-pressure reducing means being provided for each tube; and a sealed jacket housing the ends of the evaporator tubes and their connections, the jackets having lines'extending to the pump means whereby the jackets may be evacuated.

6. In a refrigeration system having compressor means, the compressor means having suction means, an evaporator comprising a plurality of elongated cylindrical tubes connected in series for the passage of refrigerant, each tube having intake means, expansion means in the intake means of each tube for causing a pressuredrop in the refrigerant as it enters each of the tubes, sealed jacket means housing the ends of the tubes, and means connecting said jacket means to the suction means for maintaining the jacket means under evacuation by the compressor.

HOMER T. CHAPPELLE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,039,796 Hiller May 5,1935 2,081,883 Philipp May 25, 1937 2,137,373 Williams Nov. 22, 1933 2,428,386 I-lubaclrer l July'l, 1947