US2232235A - Refrigerating apparatus of the compression type, and particularly to an improved evaporator therefor - Google Patents

Description

Feb. 18, 1941. HINTZE REFRIGEHATING APPARATUS OF'THE COMPRESSION TYPE, AND PARTICULARLY TO AN IMPROVED EVAPORATOR THEREFOR Filed Dec. 12, 1938 /v fl //7/ /QUDOLF #fix/72.5.

IN VENTOR.

ATTOENEYS.

Patented Feb. 18,' 1941 REFRIGERATING APPARATUS OF THE COM- PRESSION TYPE. AND PARTICULARLY TO AN IMPROVED EVAPORATOR THEREFOR Rudolf Hintze, Berlin-Charlottenbrg, Germany, assignor to Patentverwertungs-Gesellsclaft mit beschrnkter Haftung "Hermes" Berlin, Germany, a. corporation of Germany Application December 12, 1938, Serial No. %5,160 In Germany December 13, 1937 2 Claims.

The invention relates to improvements in refrigerating apparatus of the compression type, and particularly to an improved evaporator therefor.

In evaporators for refrigerating apparatus of the compression type a great number of parallel-connected conduits are often employed, which are flooded by the refrigerant. In this case the outer surface of the individual parallelconnected conduits is in direct heat exchange with the air in the cooling chamber so that the liquid refrigerant evaporates in the parallel-connected conduits and thence -passes into one or more collecting tanks or headers which are connected With a suction conduit leading to the compressor. such a flooded evaporator system does not ensure that all of the parallel-connected conduits operate as desired. The evaporation in some of them may be partly or fully prevented, for instance, as a result of a clogging with particles of the lubricant which reach the evaporator. It therefore is diflicult to attain or maintain the desired refrigerating capacity. These difliculties cannot occur in refrigerating apparatus whose evaporator is constructed accordng to the so-called dry system. Such an evaporator consists substantially of a continuous coil without branches, so that the refrigerant follows only one path in the evaporator and, consequently, the lubricant passing into the evaporator may be collected in a collecting tank communicating With one end of the evaporator coil.

The invention concerns itself with refrigerating apparatus of the compression type in which the supply of the liquid refrigerant to the evaporator is regulated by a float-controlled valve arranged at the high-pressure side exteriorly of the cooling chamber. According to the invention a single branchless conduit is employed as an evaporator and is so arranged that it communicates with the fioat-controlled valve and with the bottom of a collecting container or header to which is connected a suction conduit at such a height that the vaporous refrigerant and the lubricant entrained into the evapo- (CI. (iz-115) off to the compressor owing to the particular arrangement of the suction conduit. The connection of the evaporator coil with the lowest point of the collectingheader is particularly advantageous, since in this manner the evaporator 5 coil may always be supplied with a suflicient reserve of liquid refrigerant from the header. The evaporator system according to the invention thus represents a hybrid of the above-mentioned dry and fiooded systems and has the advantages of both without incurring their disadvantages.

The collecting container communicating with the evaporator coil is preferably designed in the form of a horizontal cylindrical tank. It is par- 'ticularly advantageous if the suction conduit connected with this tank does not extend directly to the compressor but if a second container intercepting the conduit is arranged in the cooling chamber. This second container represents an additional evaporator. If, namely, liquid refrigerant is entrained with the lubricant from the first collecting container, this liquid refrigerant is caused in the second container to evaporate. and to take up heat from the cooling chamber. This function of the two collecting containers requires that their cross sections be considerably -larger than those of the conduits connected therewith.

In the accompanying drawing is shown an embodiment of the invention in diagrammatic form. I denotes the motor-compressor set consisting of a sealed unit and supported by coil springs 2| on the ,top of the heat-insulating enclosure 22 of the cooling chamber 1. A pressure conduit 2 extends from the compressor to the air-cooled condenser 3. The liquefied refrigerant flows through a conduit 4 into a container 5 arranged exteriorly of the cooling chamber and enclosing a hoat-controlled valve 20. 0 An evaporator conduit 8 consisting of a coil formed of a single, branchlessconduit is arranged within the cooling chamber 'I and, through an extension 6, communicates with the float valve 20. The coil 8 is connected with the bottom of a container 9. This container consists of a horizontal, cylindric vessel and serves as a collecting tank for the liquid refrigerant as well as for the lubricant entrained into the evaporator. The lubricant lo which is speciflcally lighter than the liquid refrigerant collects on the surface of the refrigerant contained in the tank 9. From the interior of the tank 9 extends a connecting conduit ll to a second container |2 of similar shape and arrangement serving also as an evaporator. A suction conduit II communicating with the second container I: extends to the compressor. The motor-compressor seti and the condenser I are cooled by a fan M driven by an electric motor II mounted on the casing i of the hoat-controlled valve 20. The tan draws the cooling air over the heat-exchange ribs IS of the condenser and the cooling ribs l'l o! the motor-compressor set in the direction as indicated by the arrows.

The liquid rei'rigerant flowing from the condenser 3 through the :dost-controlled valve 20 fills up the evaporator coil t and also the collecting container 9 to a certain extent. The refrigerant evaporated in the coil 8 collects in the tank 9, whence it is drawn oi! by the conduits ll and [3. The liquid refrigerant filling the tank 8, for instance up to the level shown, constitutes a useful refrigerant reserve so that suflicient quantities of liquid refrigerant are always available in the evaporator coil also in cases where great cooling efiects are required in the cooling chamber. The retrigerant entrained with the lubricant through the conduit ll first passes into the container I! where the liquid refrigerant entrained along with the lubricant is evaporated owing to the heat exchange of this container withthe air of the cooling chamber. In this manner unevaporated refrigerant is prevented from being drawn back into the compressor I.

Instead of employing an evaporator conduit 8 eonsisting of a pipe as shown in the drawing, the evaporator system may also be constructed in any other suitable manner, for instance, !rom two sheet metal plates placed flat against each other and having registering indentations or depressions forming a continuous refrigerant conduit.

What is claimed is:

1. In a refrigerator of the compression type having a cooling chamber and a motor-driven compressor, a condenser and a float-controlled valve series-connected by refrigerant conduits and arranged outside of said cooling chamber, the combination of a collecting container arranged in said cooling chamber, a single branchless evsporator conduit also arranged in said chamber, said evaporator conduit having one end communicating with said valve and the other end connected with the bottom of said collecting container so as to ireely communicate with said 6 container, a second container arranged in said cooling chamber, a connecting conduit disposed between said nrst and said second container so as to establish a tree communication between said containers, said connecting conduit having o one end opening into the upper portion of said second container and the opening of its other end above the bottom of said ilrst container so as to draw the vaporous retrigerant and the entrained lubricant from said first to said second 15 container, and a suction conduit extending to said compressor and having its opening in said second container disposed below that of said connecting conduit, the transverse cross sections of said containers being larger than those o! 20 said connecting conduit and said suction conduit.

2. In a refrigerator o! the compression type having a cooling chamber and a motor-driven compressor, a condenser and a float-controlled valve series-connected by refrigerant conduits 25 and arranged outside or said cooling chamber, the combination of two containers of elongated shape arranged horizontally within said chamber, a single vaporator coil arranged below said containers and having one end communicating with said valve and the other end connected with the bottom of the first one of said containers, a connecting conduit orming a free communication between the upper portlons of said containers and having a cross section smaller than those of said containers, said connecting conduit having its opening in said first container arranged at such height above the bottom of said first container as to lead ofl 'vaporous refrigerant and entrained lubricant, and a suction conduit extending totsaid compressor and. having its opening in said second container disposed below that oi said connecting conduit, said suction conduit having a cross section smaller than those oi' said containers.

RUDOLF HINTZE.

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