US1919500A - Apparatus for controlling the flow of refrigerant in refrigerating apparatus - Google Patents

Description

July 25, 1933- T. E. CARPENTER LQEQGQ APPARATUS FOR CONTROLLING THE FLO OF REFRIGERANT IN REFRIGERATING APPARATUS Filed July 9, 1926 cavnewaeze Con/Wm INVENTOR. momasz Carpenter ATTORNEY.

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"Patented July 25, 1933 THOKASE. CARPENTER OF DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS,

OF TWO-THIRIDSTO ISAAC L. RICE, JR.,

0]? NEW YORK, N. Y., AND ONE-THIRD TO:

STUART C. BARNES, 0F DETROIT, MICHIGAN APPARATI IS FOR CONTROLLING THE FLOW OF REFRIGER ANT APIABATP'S' Application filed July 9,1926. Serial No, 121,301.

This invention relates to a method of and apparatus for controlling the flow of refrigerant in refrigerating apparatus. It has to do particularly with the'feeding and the control of the flow of the refrigerant into the cooling device of a mechanical refrigerating system.

It is an object of the present invention to provide means positioned between the condensing or liquefying apparatus and the cooling unit for restricting and accurately controlling thefceding of the refrigerant to such unit will be of a predetermined rate corresponding to the capacity of the refrigerating apparatus. This novel device not only restricts and controls the flow of refrigerant.

but so restricts the flow in such a novel man-' ner that only a simple, compact device is necessary which entirely does away with' ordinary expansion valves and float valves such as have been used in the past.

A further object of this invention contemplates the provision of a device which not only predetermines the flow of the liquid in accordance with the capacity of the unit, but which also positively feeds the refrigerant to the cooling device in such a manner as to prevent any back flow of the refrigerant either in a liquefied or a gaseous condition. A further object of the invention relates to the manner of restricting and feeding the refrigerant in order to obtain a high'pressure of such refrigerant and obtainin V a uniform flow of the refrigerant wit out the necessity of using a very small orifice of short length or, in other words, obtaining uniform predetermined restricted flow with a minimum ossibility of clogging or stopping of the re rigerant.

Fig. 1 is a fragmentary front elevation partially diagrammatic illustratingthe na ture of, and manner of embodying, my novel device in combination with an automatic re- Fig. 2 is an enlarged detail view partly in section, of my novel capillary tube for restricting and controlling the flow of refrigerant and also showing one manner of connecting the same to the inlet of a cooling unit.

Heretofore, in the refrigerating art, in

regulating and controlling the flow of refrigerant to the cooling device, it has been customary to use some form of an'expansion valve or some form of a float valve for maintaining theflow or level of the refrigerant to and in the; cooling unit. These various types of valves have been more or less efficient when operating ideally, but on the other hand, these various valves by reason of their complicated structure have been-the source of a large amount of service trouble'in commercial domestic mechanical refrigerating units,

The present device obviates all types of valve structures for controlling the transmission of the refrigerant to the cooling unit. It is positive in its action and is extremely compact and simple. Attempts have .been made in the past to control the flow of refrigerant to the cooling unit and to do away with the use of float valves and expansion valves by flowing the refrigerant through 11v QREFRIGERATING a very small orifice and thus restricting the flowof refrigerant to a predetermined degree. This form of restriction has not proven successful for many reasons, one of which is a tendency of such an orifice to eas-' ily clog up and thus make it necessary to stop the entire system until the orifice can be removed and cleaned. The present invention relates in a measure to the idea of restricting the flowlof the refrigerant to control its transmission to the cooling chamber, but instead of merely providing the plain restricting orifice, I have discovered that by inserting a capillary tube between the condenser supply tube and the cooling unit, that the capillary action of the refrigerant passing through this tube will create the required amount of back pressure and resistance to predetermine the rate of flow.

More specifically, my invention relates to the rovision of a capillary tube which, in its p're erred form,,is coiled so as to present a helical or spiral passageway for the refrigerant. Such a capillary tube is illustrated in Fig.- 2 and may be designated 1. It is preferably positioned adjacent to the cooling unit vand may be connected to the cooling unit intake by means of a suitable union 2 such as illustrated in Fig. 2. The intakes 3 for conare preferably somewhat larger in. diameter than the diameter of the capillary tube coils,

whereby the refrigerant is caused to expand as it enters the cooling unit. In the drawing, I have diagrammatically illustrated a refrig crating system wherein: designates a suitable compressor for withdrawing the evaporated or expanded refrigerant gases from a cooling unit 5. A condenser 6 is adapted to receive the compressed refrigerant from the compressor, and to either liquefy or maintain the liquefication of the compressed refrigerant. The' condensed refrigerant in flowing under pressure from the condenser to the cooling unit passes through the capillary tube 1 and thus its entrance into the cooling unit is restricted aiml controlled in a predetermined manner in accordance with the diameter and length of the coiled capillary tube.

By embodying capillary, action in restricting and feeding the refrigerant to the cooling unit, it is possible to use a. relatively large 7 diameter capillary tube corresponding to the,

extremely small orifice as has heretofore been necessary in using a plain restricting orifice. The length of the capillary action and the capillary tube compensates for and makes up for the relatively large diameter of the tube. In other words, the capillary tube permits of a reasonably larger hole and its resistance is created by its length. I e

I have foundthat in a refrigerating unit having a compressor operating under average pressures and a cooling unit of average capacityfa. coiled capillary tube, approximately 36 inches long and .037 inches in; diameter, satisfactorily(controls the flow 0 refrigerant and maintains the level of refrigerant in the coolin unit.

The coiled capil ary tube, by reason of .the adds additional resistance to the how of the refrigerant, and by the capillary action prevents any back flow of the refrigerant. Each helical coil acts as a little hydraulic trap and thus aitcts the positive feeding of the refrigerant towards the cooling unit. It will be understood that this capillary c o1l may be varied inlength in accordance w th the capacity of the pfiticular unit in which it is embodied, and in conformity with the predetermined rate of flow of refrigerant desired. With a certain head pressure or a certain back ppessure and with a predetermined R. P. M. of the compressor, it will be I possible to accurately regulate and predetermine the rate of flow of refrigerant to the cooling unit by utilizing the capillary coil of a, length in accordance with such predetermined head pressure and R. P. of the coin pressor. A 4

It will thus be obvious that I have provided an extremely simple, positive acting andelficient device for regulating and accurately controlling admission of refrigerant to the cooling unit of a refrigeratingsystem whereby the level ofthe refrigerant is in such unit may be maintained approximately constant due to this predetermined restriction of the refrigerant by the capillary tube.

It will be understood that where I have referred to the particular ap lication of my invention to mechanical re rigerating sys-' tems, that the word mechanical has reference to the use of refrigerating systems having a compression system operated by means of a pulsating piston type compressor.

What I claim is: a

1. In a mechanical refrigerating system of the mechanical compression expansion flooded type-the combination of a pulsating piston type compressor, a condenser, a cooling unit, and a single helical coil capillary tube positioned between the condenser and compressor, condenser and cooling unit as to restrict the flow of refrigerant and maintain the transmission to the cooling. unit at a predetermined-rate,- said capillary tube connecting with thecooling unit and condenser.

2. In a refrigerating machine of the mechanical compression, flooded type, the combination ofa compressor, a condenser and an evaporator, pipe connections between the evaporator, compressor and condenser, in the order named and a single capillary tube be tween the condenser and the evaporator of such length and diameter as will maintain a predetermined ratio. between the ressures in the condenser and evaporator during the operation of the compressorwhereby a mass .of liquid is maintained within substantially predetermined limits at all timesin said evaporator durin normal operation.

. 3..In a re rigerating machine of the me"- chanicalcompressor floodedtype, the combi nation'of a compressor,a condenser and an evaporator, pipe connections between the evaporator,condenser and compressor in the order named, and .a single capillary tube,- said tube being located between the condenser and the evaporator and of such length and diameter as will maintain a predeterminedratio between the pressures in the condenser and evaporator during theoperation of the compressor and minimize any tendency of the tube to clog, the said parts of the refrigcrating machine and the refrigerant charge being so co-ordinated that the single capillary tube is adapted to function as the regulating device of the flow between the condenser and the evaporator and by reason ofthe said co-ordination the liquid'level in the evaporator is maintained between narrow limits. g

THOMAS E. CARPENTER.

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