US2570979A - Compound system for liquid refrigerant return - Google Patents

Description

Oct. 9, 1951 H; A. PHILLIPS 2,570,979

coMPoUND SYSTEM FOR LIQUID REFRIGERANT RETURN Filed June 25, 1949 Patented ct. 9, 1951 UNITED STATES PATENT oFrlcE coMPoUND SYSTEM FOR LIQUID REFRIGERANT RETURN Harry' A. Phillips, Chicago, Ill.

Application June 2.3-, 1949, Serial No. 100,875

for returning liquid refrigerant accumulating inA the suction line andwhich embodiesV an accumu- 1ator, a liquid trap, and valve structurer whereby the high pressure gas from the discharge side of' the compressor is utilized to pump the liquid refrigerant collected from the suction line and deliver the same to' the high side of the system. The samebasicprinciple is employed in the presentinvention which, however,V constitutes an improvement since a compound systemr is provided 6 Claims-.- (Cl. 62-115) 2V figure is a perspective view of apparatus illustrati` ing a refrigerating system embodying the multi'- stage device ofv theY invention for returning liquid refrigerant so as to by-pass the compressor. Referring to the drawing, itA will bev seen that the suction line I forreturning the evaporated refrigerant from Vthe evaporatorsnot Shown, has;v TheY connection at il ywith the compressor l2- said compressor is conventional in` construction for pumping the liquid refrigerant from its point Aof accumulation to the high side of the System in two or more stages and which will be automatic in' operation and economical in the refrigerant gasY used.

Another object of the invention is to provide liquid vrefrigerant return apparatus embodying two substantially identical units which operate in sequence to elevate the liquid refrigerant from a firstliquid trap to a second trap and then from the second trap to the liquid receiver, whereby the returning liquid refrigerant is supplied to the high pressure side of the system in a manner to bypass the compressor. Y

Another' object is toY provide apparatus of the typ'e described which Will pump the liquid refrigerant accumulating in the suction return line to a level above the receiver, and which apparatus will utilize the pressure of the refrigerant gas for this purpose. The apparatus of the invenf tion has intermittent operation, which is automatic, however, since iioat valves are provided for initiating the operation when the level ofthe liquid reaches a maximum and for terminating the' operation when the liquid level reaches a minimum.

With these and various other objects in View, the' invention may consist of certain novel features of construction and operation,l as will be more fully described and particularly pointed out inthe specification,A drawings and claims appended hereto.

' In the drawing which illustrates anA embodi-` ment of the device and wherein like reference characters are used to designate like parts the and in operation, being driven by the electric motor i3 by means of van endless belt as shown. The compressorat its inlet end HY receives thelow pressure gaseous refrigerant which has been evaporated in the evaporators and by operation of the compressor the pressureof this gaseous refrigerant is increased-with a corresponding, ingv crease in temperature. The high presslll dsf' charge side of the compressor has connection at I-i with the highepressureggaseous refrigerant line I5, said line having interposedY therein theY check valve It" and which connects with the re` ceiver Il for delivering the high pressure refrig erant gas thereto'.

The cylinder forms a combination receiver and condenser so that the high pressure gaseous refrigerant from the discharge line lisLcon-` densed to a liquid'form andstofred in the receiver' until ready for use, for which purpose the re ceiver is provided with the liquid refrigerant line I connecting with the receiver at thev bottom thereof and which is provided with the hand valve I9. frigerant to the evaporators of the refrigerating system and following evaporation of the refrig'v erant, to produce'the desired cooling effect, the same is returned to the compressor through the suction line i8, thereby completing the cycle.

' Ihe invention provides an improved compound system for returning liquid refrigerant from its point of accumulation in the suction line to the,

l of liquid. refrigerant with any degree of success.

More particularly, the presentapparatus utilizesv the high pressure refrigerant gas in. twoor more stagesas a pumping medium to convey the liquid. refrigerant from they suction line tothe receiver,

As shown in thev drawing, anaccumulator. drum designated byl numeral `2t) is interposed. in the suction line I0 at a point conveniently in advance of. the compressor so. that they returning liquid refrigerant inthe suction-line is collected by the accumulator Adrumin armannerwhich,n

however, permits the refrigerant gas to continue The line [8' conducts the liquid re-Y its ow through the suction line to the compressor. The accumulator is provided with a conventional drain 2l, the same including a hand operatedvalve. not shown. by means of Which oil may be drained from the drum. The liquid refrigerant drain pipe 23 has connection with the accumulator drum at a point adjacent the bottom, the pipe including the hand valve 24 and a check valve 25. The depending end of pipe 23 connects with the top of a container or trap 26 which initially receives the liquid refrigerant from the accumulator drum 23. The present invention provides a second container or liquid trap designated in its entirety by numeral 28 and the structure for pumping the liquid refrigerant from the trap 26 to the elevated trap 28 will now be described.

The liquid refrigerant from the drum 28 naturally drains to the trap 26, it being underg stood that hand valve 24 is open to permit such drainage. Also the check valve 25 is constructed to allow the liquid refrigerant to drain downwardly into the trap 26, the check valve closing only upon pressure developing in the trap so that the pressure can be maintained in the trap and leakage to the drum prevented. The traps 26 and 28 are connected by conduit means in the form of the pipe 30, the same havingconnection with the bottom of trap 26 and with the top of trap 28. there being interposed in said pipe a check valve 3|. High pressure gaseous refrigerant is admitted to the top of trap 2t by means of the inlet pipe 32 which has connection with the three-way valve 33. The threeway valve employed for the trap 26 and likewise for trap 28 is disclosed and claimed in the copending application Serial No. 59,694, filed November 12, 1948, and whichY is characterized by an inlet for high pressure gaseous refrigerant comprising the pipe 34 and an outlet for venting the trap 26 comprising pipe 35. Referring again to pipe 34, it will be seen that the same is pro-v vided with a hand valve 36 and that the pipeen ters the high pressure gaseous refrigerant line l5 having its terminal end bent at 31 in a direction toward the flow of the gaseous refrigerant in said line l5. In a similar manner the vent pipe 35 is provided with a hand operated valve 38 and the terminal end of the same enters the suction line l0 as at 39, the said end being bent in a direction downstream with respect to the ow of the gaseous refrigerant in the suction line.

The three-way valve 33 is accordingly provided with an inlet for high pressure uid, a vent leading to the low pressure suction line, and a third connection, namely, 32, which in certain positions of the valve will deliver the high pressure fluid to the trap 26, and in other positions will connect the trap to the vent pipe 35. Control of the three-way valve is effected by means of a solenoid valve 40 having location in the by-pass conduit 4| connecting with the respective ends of the three-way valve. means of the electric terminals 42 the solenoid valve 4D is connected to a source of electric current and to the oat switches 43 and 44 associated with the trap 26, the float switch 43 controlling the solenoid in accordance with the low level of the liquid within the trap and the oat switch 44 controlling the solenoid in accordance with the high level of the liquid in said trap.

With the solenoid valve 4B open it will be seen that the high pressure gaseous refrigerant from line I5 will be permitted to ow through the inlet pipe 34 and .upon reaching the valve the action of the gaseous refrigerant is such as to close off the vent pipe 35 so that the high pressure gas flows through line 32 to the top of the trap 26. The action of the high pressure gas on check valve 25 is such as to close the Valve, with the result that pressure is applied to the liquid refrigerant in the trap causing the same to iiow through the conduit means 36 into the second trap 28, which is located above trap 26. Whenl the level of the liquid refrigerant in trap 26 reaches the low limit controlled by the switch 43 the said switch is actuated to cause de-energization of the solenoid valve 46 with the result that the valve is caused to close. As a result the action of the three-way valve is such as to close the inlet pipe 34 and to open the vent pipe 35, thus permitting the gas in trap 26 to escape to the low pressure suction line I0. The bent terminal end 39 as a result of its downstream direction within suction line if! produces a siphoning effect, drawing off the gas from the trap. As pressure within trap 26 is reduced check valve 25 automatically opens to allow liquid refrigerant from the accumulator 26 to drain by gravity into said trap 26 and when the level of the liquid within the trap reaches the maximum position controlled by float switch 44 the same is actuated to energize solenoid 46 and the cycle is repeated.

The liquid trap 28 is substantially the samev as 26 in construction and in operation, the same having intermittent operation and which alternates with 26 for discharging under pressure the liquid refrigerant to the receiver I1 located in the high side of the refrigerating system. The trap 28 is connected by the drain 45 with the receiver I1, the said drain including the check valve 46 andthe hand operated .valve 41. Thepipe 48 connects the top of trap 28 with the three-way valve 58 which is similar in all respects to valve 33. connects with the inlet pipe 5| having the hand operated valve 52 and which enters the high pressure gaseous refrigerant line I5, the said terminal end 53 of the pipe being bent up-stream against the direction of flow of the gaseous refrigerant within pipe I5. The other side of the three-way valve connects with the `vent pipe 54 having the hand operated valve 55 and which enters the suction line I6, the terminal end 56 of which is bent downstream as regards the ow of the gaseous refrigerant in said line i0. The solenoid valve 51 is located in the by-pass conduit connecting the respective ends of the three-way valve 56. terminals 58 the solenoid valve 51 is connected with a source of current and with the float switches 66 andl associated with the trap 28. Float switch 6@ controls solenoid valve 51 in accordance with the low level of the liquid in the trap, whereas, the float switch 6l controls the solenoid valve in accordance with the high from trap 26 to trap 28 it will be seen that the high level ofthe liquid in the latter trap will influence float switch 6| which will energize the solenoid valve 51, opening the valve and thus,

One side of the valveV By means of the electric' to the gavetta' forces the liquid refrigerant within vthe trap. to

flow through drain 45 into receiverr I'ir the liquid reaches a predetermined. 10W Ievel the ducedvvhich faciiitates the drawing ofv the gas from the trap and` its discharge into the low pressure suction line l0.' l

In the apparatus of the invention for returning liquid. refrigerant so as to Aby-pass the compressor, the refrigerant is subjected to two or more pumping operations,l the rst one elevating the refrigerant to a trap above the receiver and. thesecond. pumping operation discharging the refrigerant to the receiver. Substantially equivalent structure including the liquid traps 26 and 2,3 and associated valves is provided for respective pumping operations which take place in an alternate manner as regards the traps and wherein each trap has operation intermittently. Also both pumping operations employ the high pressure gaseous' refrigerant'and which is admitted to the topf-,of the liquidi trap to: effect discharge of the liquid refrigerant from the bottomthereof, with the start and', termi"- nation of each pumping operation beingautomatic as the same is controlled? by the maxiand; minimum level float switches. The invention is not. to be' vlimited to orr` detaiis of construction of the particular embodiment thereof illustrated by the drawings as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

I. In a refrigerating system including the conventional compressor having a suction line for returning evaporated refrigerant to the compressor and having a high pressure refrigerant line, an accumulator drum interposed in the suction line for collecting liquid refrigerant to prevent delivery of the same to the compressor, a liquid trap located below the accumulator drum and having connection with the drum for receiving liquid refrigerant therefrom by gravity flow, a second liquid trap having anl elevated position with respect to the first mentioned trap, conduit means joining said traps, means supplying high pressure gaseous refrigerant from said high pressure refrigerant line to the first mentioned trap to effect a iloW of the liquid refrigerant therein through said conduit means to the second trap, a connection from the second trap to the high pressure refrigerant line, and other means supplying high pressure gaseous refrigerant from said line to the second trap to effect flow of the liquid refrigerant in the suction trap through said connection to the high pressure side of the system.

2. In a refrigerating system, in combination, a suction line for delivering evaporated refrigerant to the compressor of the system, a high pressure refrigerant line connecting with the discharge side of the compressor, a container adapted to receive liquid refrigerant from the suction line, a second container having an elevated position With respect to the first mentioned container, conduit means joining said containers, means supplying high pressure gaseous refrigerant'froin said' high pressure refrigerant. une f'ojf the first.- mentioned container to effect a flow of the liquid refrigerant through said' conduit means to the second container, said means having operation to vent the said rst mentioned container to the suction line during the period' When thesupply of said gaseous refrigerant is stopped, a connection from the second container to the high pressure refrigerant line, other means sup"- plying high pressure gaseous refrigerant froiiiv said line to the second container to euect flow.

of Vthe liquid refrigerant through said connection to the. high pressure side of the system, and

said otherV means having operation to vent theik second container to the suction line during the' period when the supply of gaseous refrigerant stopped.

32 In a refrigerating system including. the coiiventional compressor havingv a suction line for returning evaporated refrigerant to the coinpressor'and havingV a high pressure refrigerant` line, an accumulator in the suction line for col'- lecting liquid refrigerant to prevent delivery of the same to the compressor, conduit means providing a passageway connecting the accumulatorv with a receiver in the high` pressure refrigerant line, said conduit means including first and sec- 0ndvalved containers with the. second containerl having a position above the first container', andY means supplying high pressure gaseous refrigerant from said high pressure refrigerant line to the containers in an` intermittent and alternatemanner,` whereby to pum-py the liquid 'refrigerant in the first container to the second container and then from the second container to the receiver.

4. In a refrigerating system including the conventional compressor having a suction line for returning evaporated refrigerant to the compressor and having a high pressure refrigerant line, an accumulator in the suction line for collecting liquid refrigerant to prevent delivery of the same to the compressor, means connecting the accumulator with the high pressure refrigerant line including a first and a second container With the second container having a position above the first container, means supplying high pressure gaseous refrigerant from said high pressure refrigerant line to the rst container for discharging liquid refrigerant from the first container to the second container, other means supplying high pressure gaseous refrigerant from said line tothe second container for discharging liquid refrigerant from said second container to the high pressure refrigerant line, said means and said other means each including a three-way Valve having tvvo operative positions, in one position each valve being operative to connect the high pressure refrigerant line to its respective container and in the second position each valve being operative to connect its respective container to the suction line.

5. In a refrigeratng system, in combination, a suction line for delivering evaporated refrigerant to a compressor of the system, a high pressure refrigerant line connecting with the discharge side of the compressor, a container adapted to receive liquid refrigerant from the suction line, a second container having an elevated position with respect to the first mentioned container, conduit means joining said containers, means supplying high pressure gaseous refrigerant from said high pressure line to the first mentioned container to effect a flow of the liquid refrigerant therein through said conduit means to the second container, said means having operation to vent the said rst mentioned container to the suction line during the period when the supply of said gaseous refrigerant is stopped, a connection from the second container to the high pressure refrigerant line, other means supplying high pressure gaseous refrigerant to the second container to eiect' ow of the liquid refrigerant through said connection to the system, said other:

means having operation to vent the second con-` tainer to the suction line during the period when the supply of gaseous refrigerant is stopped, the means supplying high pressure gaseous refrigerantto the rst mentioned container and the other means supplying high pressure gaseous 're` frigerant to the second container each including a three-Way valve, and electric means associated with each valve for controlling the opera'- tion thereof in accordance With the level 'of the liquid in its respective container.

6. In a refrigerating system including the con-` ventional compressor and having a high pressure refrigerant line, the combination of an ac-A and the first container, said check valves permitting flow of the liquid refrigerant in one d1- rection only from the drum to the line, means tapping the high pressure refrigerant line and connecting with the containers respectively adjacent the top thereof for supplying high pressure gaseous refrigerant thereto, whereby to effeet-flow under pressure of the liquid refrigerant in 'ai two-stage operation from the rst to the second container and then from the second con--V tainer to the line, valve members associated with said high pressurerefrigerant supplying means for controlling respectively the supply of said gaseous refrigerant to the containers, and said valve members each operating to vent its re-V spective container to the suction line during the time gaseous refrigerant is not supplied to the container.

HARRY A. PHILLIPS.

Y REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,106,244 Schleimann Aug. 4, 1914 1,106,287 Doelling Aug. 4, 1914 2,032,286 Kitzmiller Feb. 25, 1936 2,123,021 Phillips July 5, 1938 2,156,426 Brown May 2, 1939 2,164,081 Phillips 1 June 27, 1939 2,193,261 Thomson Mar. 12, 1940 2,267,152 Gygax Dec. 23, 1941

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