US 2079687 A
Description (OCR text may contain errors)
vPatented May Il; 1937 A Wilfred Fournesl, Oakland, Calif., alslgnorfby mesne assignments, to Fonrness Development Corporation, Ltd.
Application april A4. 1932'. serial no. ceases This invention relates to a refrigerating system, and especially to one employing a refrigerant circulating in a closed-circulatory path. Such systems in general are well known, and usually employ such mediums as sulfur dioxide or its equivalent.
I'he medium is placed in a liquid stage, 4and then permitted to evaporate or "expand in a closed space, such as a coil or chamber. The process of evaporation into a gas or'vapor form entails absorption of heat, producing the desired refrigerating effect at and adjacent the expansion coils. After evaporation, the gas is led to a compressor where it is compressed, and then it is passed to a condenser where it is recon"- densed. There it is. allowed to pass as needed pens that the condenser exhibits a Vtendency to retain some of the condensed liquid, thereby causing a higher discharge pressure between the` compressor and the condenser, than if the condenser were completely purged of the liquid. It is one of the objects of my invention to make it possible to purge the condenser completely, thereby ensuring favorable operating conditions for the condenser; and especially by providing an intermediate receiver to which the condenser discharges, and in which the pressure is lower than in the condenser. This lowering of pressure is preferably accomplished by the aid of aI cooling means in or near this receiver, such as a water cooling coil, or a small expansion coil through which the refrigerant must pass.
It is also sometimes desirable to operate a number of compressors in parallel for a single retrigerating system. In such installations, two or more compressors are driven either by a common source of power or by independent sources, and the vaporized or gaseous refrigerant from the expansion coil is led to the intakes of all the compressors. Each compressor has its own con-f denser, and then the condensedrefrigerant from all of the condensers is fed to a common control valve to the expansion space.
Under such circumstances, the division of the load between the compressors is apt to be very unequal. This may be due to slight dinerences between the respective intake pressures, or the respective discharge pressures, which may initiate a condition that progresses toward extremelyv heavy load conditions for some or one of the 1n (c1. ia-11s) units, and extremely light load conditions-for other units.
It is another object of my invention to ensure substantially equal load division between compressor units.
This I accomplish by using a common intermediate receiver into which all of the condensers discharge. This intermediate receiver is so'arranged that it completely purges all of the condensers, as by cooling itin the manner hereinabove described.
My invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of my invention. For this purpose -Ihave shown a few forms in the drawing accompanying and forming part of the present speciiication. I shall now proceed to describe these forms in detail, which illustratethe general principles of my invention; but it is'to be understood that this detailed description is not to be taken in a hunting sense, since the scope of my invention is best definedl by the appended claims.
Referring .to the drawing:
Figure 1 is a diagram'of a system utilizing a l single compressor, in which my invention is incorporated; and
Fig. 2` is a. similar diagram of a system utilizing a number of compressors.
In Fig.'l the closed cycle for the refrigerant includes an expansion or evaporation space Ii, usually in the form of a collof tubing. It is in this space that the liquid refrigerant absorbs heat. From the space Il the refrigerant isv led as by a conduit I2, to the inlet of a compressor I3. The discharge from this compressor connects to a condenser il, where the compressed gas is condensed. Y
With my invention, there is provided a receiver Ii into which the .condenser discharges, and which retains the liquid refrigerant until it is passed to the space Il. This intermediate receiver is maintained at a temperature less than that of condenser Il, as by artificial cooling, and in a 'manner that will be described shortly. In this way. there-is an assurance that the pressure in receiver I5 is less than in the condenser Il, and therefore the condenser Il will be completely purged of the condensed rei frigerant.
The refrigerant then proceeds as by conduit or pipe I6, to a valve l1, such as an expansion valve, for automatically feeding the refrigerant to the space Il, intermittently as required. But
` the before the refrigerant reaches -this space. it is caused to travel through a cooling coil Il in-or near receiver I! for cooling it. To effect this result, a pipe I9 leads from valve I'I to coil I8, and from there. a pipe 20 conducts the refrigerant 4to the space II. In coil I8, a slight evaporation is permitted to absorb heat from the refrigerant collected in receiver I5. This causes a slight temperature differential between the receiver I5 l0 and the condenser Il, of the order of a few degrees. The refrigerant, after expanding in space II, then repeats the cycle.
The mode of operation of the system is apparent from the foregoing. The condenser I4 is l purged from all its refrigerant and compressor I3 can operate at its best eiciency.
The use of an intermediate receiver is especially beneficial where there are a plurality of compressors operating in parallel as in Fig. 2. Here the compressors 2I, 22 have their inlets connected by way of the common pipe 23 to the outlet of expansion space II. Each compressor however discharges to its own condenser 24 or 25; but both condensers discharge into the comc mon intermediate receiver I5, as by the aid of the branched pipe 26. Thence the refrigerant proceeds as before through the valve I1, pipe I9, cooling Acoil I8 in receiver I5, and pipe 20 to space II. Due to the use of the common receiver I5, which is kept by cooling it, at a lower pressure than condensers 2l, 25, these condensers arev kept purged of refrigerant. Accordingly the division of the load between the `compressors is 3J stabilized, beth inlet and outlet pressures being maintained substantially uniform for all of the compressors. I
I claim: 1. In' a refrigerating system utilizing a re- 40 frigerant that is cyclically liquefied, evaporated, and compressed by' the aid of a compressor, the process which comprises condensing the refrigerant after it is compressed, passing the refrigerant after it is condensed, to a region at a temperature slightly below that of the space where the liquid is condensed, and retaining the refrigerant in that region until it is passed to an evaporating space.
2. In a refrigerating system utilizing a refrigerant that is cyclically liquefied, evaporated, and compressed by the aid of a compressor and a condenser into which the compressor discharges, the process which comprises passing the liquid refrigerant from the condenser into an intermediate receiver, and cooling said receiver so that there is a slight temperature differential between the' receiver and the condenser by expansion of therefrigerant in its passage to the evaporation space. 3. In a refrigerating system utilizing a vaporizable refrigerant, a compressor, a condenser, an intermediate receiver to which the condenser discharges, and where the refrigerant is retained and means for maintaining said receiver at a slightly lower temperature than the condenser,
comprising a cooling coil in the receiver.
4. In a refrigerating system utilizing a vaporizable refrigerant. a plurality of compressors operating in parallel. and means ensuring against substantial load inequality between the .compressors comprising condensers connected with the compressors, an intermediate receiver for drawingl condensed refrigerant frorneach condenser, and means forming a lcommonexpansion space connected to the intermediate receiver. 5L In a refrigerating system utilizing a vaporizable refrigerant, a plurality` of compressors operating in parallel, a condenser for each comy pressor,` an intermediate receiver into which all of -the condensers discharge. and where. the liquid refrigerant is retained until it is passed to an evaporating space, and means for maintaining, said receiver at a temperature below that in'the condensers.
6. In a refrigerating system utilizing a vaporizable refrigerant, a plurality of compressors` operating in parallel, 'a condenser for each compressor, an intermediate receiver into which all of the condensers discharge, and where the liquid refrigerant is retained'until it is passed to a common evaporating space, and means for cooling said receiver to a temperature below that in the condensers.
7. In a refrigerating system utilizing a vaporizable refrigerant, a plurality of compressors operating in parallel, a condenser system connected to the compressors, means forming a common expansion space discharging to the compressors and an intermediate receiver into which the condenser system discharges, and where the refrigerant'liquid is retained until it is passed to an evaporating space.
8. In a refrigerating system utilizing a vaporizable refrigerant, a plurality of compressors operating in parallel, a condenser system connected to the compressors, an intermediate receiver into which the condensers discharge, and
'where the liquid refrigerant is retained until it is passed to the evaporating space, and means for cooling said receiver below the temperature of the condenser system.
9. In a refrigerating system in which a vaporizable refrigerant is used, a compressor. a condenser, an intermediate receiver in which said refrigerant is retained, aconduit connecting thel condenser and the intermediate receiver, and means forming a circuit from the intermediate receiver back to the intake of the compressor, said circuit including an expansion space and a path in series with said space and in heat exchange relation with the interior of the receiver for causing a slight temperature differential to exist between the interior of the receiver and the interior of the condenser.
10. In a refrigerating system in which a vaporizable refrigerant is pressors, a condenser system into which the compressors discharge; an intermediate receiver into which the condenser system discharges, and means forming a circuitI from the intermediate receiver to the intake of the compressors, said circuit including an expansion space and a path in series with said space and in heat exchanging relation with the interior of the receiver to reduce the temperature of said interior.
used, a plurality of com-