US 3919859 A
A recirculating refrigeration system. The system includes a receiver tank separated into an upper chamber and a sump chamber by a bulkhead. Liquid refrigerant from a condensor is delivered to said receiver tank above said bulkhead and accumulates thereon to a predetermined level. Excess liquid flows into said sump chamber from where it is delivered to an evaporator. Vaporized refrigerant is returned to the upper chamber of the receiver tank below the liquid level to cool it before it is returned to a compressor and from there, in liquid form, back to the condenser.
Description (OCR text may contain errors)
United States Patent 1191 Ross 1 1 Nov. 18, 1975 REFRIGERATING SYSTEM Primary Errzminer-William F. ODea 75 Inventor. R bert R wh t i L Assistant Examiner-Ronald C. Capossela I 1 0 ea on Attorney, Agent, or FirnzHume. Clement, Brinks,  Assignee: H. A. Phillips & (30., St. Charles, lll. Willi Olds, & Cook, Ltd.
 Filed: Nov. 18, 1974  Appl. No.: 524,779  ABSTRACT A recirculating refrigeration system. The system in- U-S- cludes a receiver tank separated into an upper Chum-  Int. Cl: F25B 43/00 ber and a Sump Chamber by a bu|khead Liquid f i  F'eld of Search 62/503 509, erant from a condensor is delivered to said receiver 62/174 M9 tank above said bulkhead and accumulates thereon to a predetermined level. Excess liquid flows into said  References C'ted sump chamber from where it is delivered to an evapo- UNITED STATES PATENTS rator. Vaporized refrigerant is returned to the upper 2,581,044 1/1952 Ratcliff 62/149 Chamber Of the receiver tank below the liquid level to 2,641,] 13 6/1953 Schumacher cool it before it is returned to a compressor and from 2,667,756 2/1954 Atchison there, in liquid form, back to the condenser. 2,79l,l0l 5/1957 Zearfoss, Jr. 62/509 X 4 Claims, 1 Drawing Figure ,21 32 25 29 5 Condenser I I 2? I i I Z J 28 6 e01. W i 70 3O 58 i 15 Accumulator l 1 l I Condenser US. Patent NOV. 18, 1975 3,919,859
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PO 1 a ZPK REFRIGERATING SYSTEM FIELD OF THE INVENTION This invention is in the field of refrigeration. It relates more particularly to refrigeration systems of the large, industrial type.
BACKGROUND OF THE INVENTION H. A. Phillips & Co. of Chicago, Illinois, assignee of this application, has long been a leader in the design, development and installation of industrial type refrigeration systems. A pioneer in recirculating systems, its engineers have constantly sought new and improved refrigeration systems and equipment. Systems and components for refrigeration which have been developed at Phillips include those disclosed in Phillips U.S. Pat. No. 2,570,979; Phillips U.S. Pat. No. 2,589,859; Phillips U.S. Pat. No. 2,641,281;Richards U.S. Pat. No. 2,841,962; Richards et al. U.S. Pat. No. 2,871,673, and Ross U.S. Pat. No. 2,966,043. Of course, research and development continues toward more efficient and less expensive systems.
SUMMARY OF THE INVENTION It is an object of the invention to provide an improved recirculating refrigeration system. It is another object to provide a recirculating refrigeration system employing a new and improved combination intercooler and receiver. It is still another object to provide a system receiver of this type which cools returning refrigerant gas in refrigerant liquid from the condenser without passing the gas through sub-cooled liquid being forced to the evaporators.
BRIEF DESCRIPTION OF THE DRAWING The system embodying features of the invention, including its method of operation, together with additional objects and advantages thereof, is illustrated in the single schematic drawing FIGURE of the system.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing FIGURE, a refrigeration system embodying features of the present invention is illustrated schematically at 10. The system is designed to provide highly efficient refrigeration in an industrial plant, for example, through the medium of an evaporator unit or units 1 1 which receive liquid ammonia refrigerant. In this light, the system 10 is adapted for the use of liquid ammonia refrigerant, but other refrigerants might also be used in systems embodying features of the present invention, including halogen compounds or methanes, for example.
The evaporator 1 1 receives refrigerant liquid through line from a combination intercooler and receiver tank 16. The tank 16, in turn, receives liquid refrigerant from the condenser through a line 21 in which a high side or liquid level control unit 22 is interposed.
The condenser 20 has received ammonia gas under a pressure of approximately 185 psi from the systems compressor through a high pressure gas line 32. The conventional condenser 20 liquifies the hot gas by removing a substantial portion of its heat while the gas is under pressure. Liquified ammonia leaves the condenser 20 through the line 21 hereinbefore referred to.
The flow of refrigerant liquid to the combination intercooler and receiver tank 16 is regulated by the high side" control unit 22. The control unit 22 is effective to regulate flow of liquid to the tank 16 depending upon the level of liquid in the line 21. As long as the level of liquid in the line 21 is above a predetermined level, the unit 22 is effective to open line 21 to the passage of liquid, permitting liquid to flow to the tank 16. A pressure drop occurs across the control unit 22 and, as a result, the pressure in the tank 16 is approximately twenty-five to forty (25-40) psi. If the liquid level in the line 21 drops below a predetermined point, the unit 22 closes the line 21 until additional liquid builds up therein.
The combination intercooler and receiver tank 16 is, according to the invention, separated into an upper chamber 25 and a lower chamber 26 by a horizontal bulkhead 27. The bulkhead 27 is fluid tight, except for a liquid level maintenance pipe 28 which extends vertically through it. As illustrated, the upper end 29 of the pipe 28 extends a predetermined distance above the bulkhead 27. This distance determines the depth to which liquid will accumulate on the bulkhead 27.
Liquid refrigerant from the condenser 20 is introduced to the tank 16 through the line 21 above the bulkhead 27. It accumulates on the bulkhead 27 up to the level of the upper end 29 of the pipe section 28. The liquid refrigerant then pours down through the pipe section 28 into the lower chamber 26 of the tank 16, which acts as a liquid refrigerant sump. The liquid in this sump chamber 26 is, at this point, sub-cooled and under a gas pressure of approximately 30 psi.
Liquid refrigerant from the sump chamber 26 of the tank 16 is forced to the evaporator l 1 when it performs its refrigerating function, as has been pointed out, in an industrial freezer, for example. A combination of liquid and gas departs the evaporator 11 through the return line 40 to a low temperature accumulator 41. The accumulator 41 returns the liquid refrigerant to the combination intercooler and receiver tank 16 in a manner hereinafter discussed, through the return line 42 connected by a branch line 43 to a dump tank 44. Check valve 46 in the line 42 prevents backflow of liquid refrigerant from the sump chamber 26 of the tank 16 to the dump tank 44, while check valve 48 prevents backflow of liquid from the dump tank 44 to the accumulator 41.
The vaporized refrigerant; i.e., gas, in the accumulator 41, flows through the return line 50 to the upper chamber 25 of the tank 16. A booster compressor 51 in the line 50 raises the gas pressure to approximately 30 psi before this gas reaches the chamber 25. In the chamber 25, the line 50 terminates in a free end 53 which is below the level of the upper end 29 of the pipe section 28. Accordingly, gas from the line 50 at approximately 30 psi is emitted below the level of liquid on the bulkhead 27. This superheated gas is cooled by the refrigerant liquid.
The combination intercooler and receiver tank 16 is constantly receiving refrigerant vapor or gas in the aforedescribed manner. Flash gas is also being produced in the tank 16 in a well-known manner. This gas finds its way down through the pipe section 28 into the sump chamber 26 of the tank 16, where it is drawn out of the tank 16 through the gas return line 58. The gas return line 58 returns gas at a pressure of approximately 30 psi to the compressor 30. The compressor 30 functions in a manner hcreinbefore described to recompress the gas to approximately 185 psi, and the cycle is then repeated.
Tapped into the high pressure output line 32 is a high pressure branch line 60H. The line 60H is connected to a three-way dump valve 61 which is, in turn, connected through a low pressure brance line 60L back to the accumulator 41.
The three-way dump valve 61 also is connected, through a high pressure branch line 70, to the dump tank 44. Normally, the outlet of the valve 61 to the line 70 is closed while liquid refrigerant arriving in the accumulator 41 flows by gravity through the lines 42 and 43 into the dump tank 44.
When the liquid level in the dump tank 44 rises to a predetermined point, the port in the dump valve 61 which is connected to the line 70 opens so that high pressure gas flows through the line 70 into the dump tank 44. Pressure build-up in the dump tank 44 forces liquid refrigerant in the tank 44 through the lines 43 and 42 and past the check valve 46 into the combination intercooler and receiver tank 16.
When the dump tank 44 has been emptied, as indicated by a level sensor, or after a predetermined timedelay period calculated to empty the tank, the high pressure outlet port of the three-way dump valve 61 closes and the low pressure outlet port to the line 60L opens. Pressure in the dump tank 44 and the accumulator 41 is equalized. Dumping stops and liquid refrigerant again is permitted to flow by the force of gravity through the lines 42 and 43 from the accumulator 41 to the dump tank 44.
According to the invention, the construction and arrangement of the combination intercooler and receiver tank 16 in the system permits gas from the accumulator 41 to be passed through liquid refrigerant in the tank without disturbing the sub-cooled liquid in the sump chamber 26 of the tank. This gas is introduced through refrigerant liquid above the bulkhead 27.
While the embodiment described herein is at present considered to be preferred, it is understood that various modifications and improvements may be made therein, and it is intended to cover in the appended claims all such modifications and improvements as fall within the true spirit and scope of the invention.
What is desired to be claimed and secured by Letters Patent of the United States is:
1. A recirculating refrigeration system, comprising:
a. compressor means for compressing vaporized refrigerant,
b. condenser means for receiving compressed refrigerant gas from said compressor means and removing heat from said compressed gas to liquify all of a substantial portion of it,
0. receiver tank means for receiving liquified refrigerant from said means,
d. said receiver tank means including an upper chamber and a lower chamber separated by a bulkhead,
c. said upper chamber being connected to said condenser means for receiving said liquified refrigerant from said condenser means,
f. liquid level control means in said upper chamber for permitting a predetermined level of liquid refrigerant to accumulate on said bulkhead while causing any additional amount ofliquid refrigerant to flow into said lower chamber and accumulate in a sump therein,
g. evaporator means,
h. liquid refrigerant from said sump being forced from said lower chamber to and through said evaporator means,
i. at least a substantial portion of said vaporized refrigerant from said evaporator means being returned to said upper chamber of said receiver tank means and introduced to said upper chamber below the level of liquid refrigerant on said bulkhead so as to cool said vaporized refrigerant,
j. means for permitting said cooled, vaporized refrigerant to return from said upper chamber to said lower chamber above said sump, and
k. means for returning said cooled, vaporized refrigerant from said lower chamber to said compressor means.
2. The refrigeration system of claim 1 further characterized in that:
a. said liquid level control means comprises pipe means extending vertically through said bulkhead,
b. the height of an open upper end on said pipe means establishing the liquid level in said upper chamber,
0. overflow liquid flowing down through said pipe means into said lower chamber sump,
d. cooled, vaporized refrigerant also passing into said lower chamber from said upper chamber through said pipe means. I
3. The refrigeration system of claim 1 further characterized by and including:
a. an accumulator tank for receiving vaporized refrigerant and liquid refrigerant entrained therein from said evaporator means,
b. vaporized refrigerant in said accumulator tank being first compressed and then returned to said upper chamber of said receiver tank means,
c. and means for returning accumulated liquid refrigerant in said accumulator tank means to said lower chamber sump in said receiver tank means.
4. The refrigeration system of claim 3 further characterized in that:
a. said means for returning liquid refrigerant from said accumulator tank to said lower chamber sump of said receiver tank means including a dump tank and dump tank valve connecting said dump tank to a source of compressed refrigerant gas,
b. actuation of said dump tank valve being effective to permit compressed refrigerant gas to force accumulated liquid refrigerant in said dump tank into said lower chamber sump.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,919,859 Dated November 18, 1975 Inventor(s) ROBERT R. ROSS It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 3, line 53, "of" should be --or-,
Line 55, after "said" insert "condenser-n Signed and Scaled this twenty-fourth of February 1976 [SEAL] A ttes t:
RUTIIC. MESON c. MARSHALL DANN- Am'stmg ()jjicer ('mnnu'ssiuner oj'larenrs and Trademarks