US2677944A

US2677944A - Plural stage refrigeration apparatus

Info

Publication number: US2677944A
Application number: US198602A
Authority: US
Inventors: Alonzo W Ruff
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-12-01
Filing date: 1950-12-01
Publication date: 1954-05-11
Anticipated expiration: 1971-05-11

Description

May 11, 1954 w U 2,677,944

PLURAL STAGE REFRIGERATION APPARATUS Filed Dec. 1, 1950 3 Sheets-Sheet l I l l I L EI APOZAZ'ORS 25 V 25 J2 INVENTOR 4/0020 Ruff ATTORNEY May 11, 1954 w, RUFF 2,677,944

PLURAL STAGE REFRIGERATION APPARATUS 3 Sheets-Sheet 2 Filed Dec. 1, 1950 II II.' I

INVENTOR 6/ V I /4/ 0/720 M fluff ATTORNEY y 11, 1954 A. w. RUFF 2,677,944

PLURAL STAGE REFRIGERATION APPARATUS 3 Sheets-Sheet 3 2%. 5.

Filed Dec. 1, 1950 INVENTOR 4/0/720 W Ruff ATTORNEY Patented May 11, 1954 PLURAL STAGE REFRIGERATION APPARATUS Alonzo W. Ruff, York, Pa. Application December 1, 1950, Serial No. 198,602

Claims.

This invention relates to refrigeration systems and more particularly to a booster compressor stage, and improvements in the cooling and sealing of booster compressors.

In mechanical refrigeration systems of the compressor-condenser-expander circuit type, it is ofte desirable to increase the refrigeration capacity of the system. Increased capacity may be necessary in order to permit the handling of deep frozen food products now in wide use, or topermit research laboratory tests at relatively low temperatures. The improved compressor disclosed herein has been found well suited for addition to existing refrigeration systems to greatly increase refrigeration capacity by making it possible to lower the effective evaporator temperature.

It is an object of this invention to provide an efiicient booster compressor for initially compressing a gaseous refrigerant medium.

It is another object of this invention to provide a refrigerant compressor having improved cooling and sealing means.

It is another object of this invention to provide a refrigerant compressor which is relatively small in size and easily installed in existing refrigeration systems.

It is a still further object of this invention to provide a booster compressor, together with cooling and sealing circuits, which is eflicient in operation and relatively low in cost.

Other objects, advantages and features of the present invention will become readily apparent from the following description of the embodiment illustrated in the accompanying drawings where- 1n:

Figure 1 is a diagrammatic illustration of a refrigeration system including a booster comprescor stage.

Figure 2 is a horizontal sectional view of a preferred form of compressor and taken on line 22 of Figure 3.

Figure 3 is a vertical sectional view taken on line 3-4 of Figure 2.

Figure 4 is a diagrammatic illustration of a preferred arrangement of cooling and sealing circuits for the compressor shown in Figures 1, 2 and. 3.

Figure 5 is a diagrammatic illustration of a modified arrangement of cooling and sealing circuits.

Referring to the drawings, the exemplary embodiment of the invention is shown applied to a closed refrigeration system including evaporators I l and I 2 supplied with liquified gaseous refrigerant from a receiver I3 by line It. The gaseous refrigerant from the evaporators H and I2 is conducted to compressors l5 and It by line I! and passes to the condensers I8 through line l9, and liquified refrigerant from the condensers is collected in the receiver 13. Conventional details such as evaporator, compressor and receiver controls, and condenser cooling means are not shown in the diagrammatic illustration. The compressor booster stage includes a compressor connected in the line I! between the evapo rators and the conventional compressors I5 and It. A duplicate compressor may be connected in parallel with the compressor 20 where required. An intercooler 2! may also be connected in the gas line I! between the booster 2i! and the compressors l5 and I5. Suitable valves are provided in connection with line I? for connecting-in or by-passing the booster 20 and the intercooler 2|. The booster compressor 20 is provided with a cooling jacket described hereinafter, and the liquid cooling medium utilized in said jacket may be passed through a heat dissipating coil 22 located, for example, in the floor of a room or chamber containing the evaporators H and I2 to prevent freezing and buckling of such floors.

Referring to Figures 2 and 3, the booster compressor 20 is preferably of the rotary vane type having a casing 25 with a cylindrical bore. The casing 25 is provided with an inlet 26 and with an outlet 2'! for gaseous refrigerant. The casing 25 is provided with a head 28 at one end having an oif-center bearing 29 for the cylindrical rotor 30. The head 28 is closed by a plate 3|. The other end of the casing 25 is provided with a head 32 also containing an off-center bearing 33 for the drive shaft 3% extending outward from the rotor 30. Sliding vanes 35, radially disposed, are arranged in slots in the rotor and are urged outward into contact with the inner surface of the casing 25 when the rotor is driven by the shaft 34. A shaft seal casing 36 is secured to the head 32 and includes spaced packing members 31 and 3B engaging the drive shaft 34. A flap-type check valve 39 may be provided in the compressor outlet 2.1, and a lubricant inlet 40 may be provided in the inlet 26. The compressor shaft 34 may be driven by any suitable means such as the direct drive motor 4! illustrated in Figure 4. The motor li may be in line with the compressor shaft 34 and be coupled thereto by a suitable coupling 52, or the motor may be mounted above the compressor 20 to conserve space, in which event a belt and pulley, chain, or gear drive may be used.

The compressor casing Figure 5, is provided with passages 45 forming a cooling jacket surrounding the rotor 35. An inlet and an outlet d5 are connected to the cooling jacket passages 45. The head 23 is also provided with passages 38 communicating with the passages d5 to permit cooling of the shaft bearing 29. The head 32 has similar passages 49 communicating with the passages 45 for cooling the bearing 33. The shaft seal casing 36 is provided with passages 56 connected with the coolant outlet 45 by the line 55 and with the coolant inlet by line 5? for cooling the shaft seals 8? and 38. Casing 36 also has an inlet 51 and an outlet 52, Figure 2, for the chamber 53 between the seals 3": and 38 so that liquid under sufficient pressure may be provided in said chamber to prevent any leakage of air into the compressor and to prevent any leakage of refrigerant gas outward through the seal 31.

The cooling and sealing circuits illustrated in Figure 4 will now be described. The compressor 28 is cooled by an anti-freeze liquid, such as oil, circulated through the

jacket passages

45, 48, 4S, and 56, by means of pump 65. Hot liquid from the compressor jackets may, for example, be circulated through the

lines

54 and 62 to a coil 22 embedded in the floor of a low temperature refrigerated space to prevent floor buckling, or it may be circulated through the cooler 6|, the latter being a conventional heat exchanger including coils through which cold water may be circulated. The cooled liquid is then pumped into the jacket inlet fill and into line 5! to the seal jacket 5%. Cooling liquid may be added to this circuit at an expansion tank 63. The circulated cooling liquid cools the

compressor bearings

29 and 33 as well as the

shaft seals

31 and 38.

Liquid, such as oil, is supplied to the shaft seal chamber 53 through inlet 5!! and may be circu lated by pump ti; connected to the outlet 52, as shown in Figure 4. The sealing oil is pumped by pump 68 through a strainer 6'! and thence through line 68 to a seal oil pct 89. The closed oil pct 69 may be provided with a cooling coil 18 through which water is circulated and may have a filler cap ii to permit the addition of oil to the sealing oil circuit. Sealing oil flows from the pct 69 through

lines

22 and 13 back to the seal housing inlet 5!. The sealing oil may be passed through a coil is wrapped around the compressor gas inlet pipe "i5, if desired, for cooling the seal oil. The compressed gas outlet 21 is provided with a cut off valve St in the line 8|. A pipe 82 conducts compressor outlet pressure through a two-way check valve unit 83 to the seal oil line E2. The check valve unit 83 comprises two check valves 8d and 85. The check valves may be spring loaded ball type check valves, as shown in Figure 5, and valve 84 is effective to communicate the compressor outlet pressure in line Si or in compressor outlet 21 to the sealing liquid in line 72. Valve 85 is effective to vent excessive pressures in the sealing liquid line ll! to the compressor outlet line. The check valve unit 8 5 may be connected directly to the compressor outlet line 2'! as shown by the line 86 in Figure 5. This alternative connection 86 is also shown in dotted lines in Figure 4. Other forms of pressure equalizing devices, such as diaphragms, bellows, pistons, or the like, may be used in place of the double check valve unit 83.

The modified seal oil system shown in Figure 5 is similar to that shown in Figure 4 except that the seal oil is not circulated by a pump and 2.5, as shown best in not cooled other than by the cooling jacket passages 50 in the seal casing 36. In the Figure 5 system the passage 50 is provided with an inlet 5| but has not outlet connection. The inlet 5| is connected to an oil pot 88 which may have a visual sight gauge 89 to indicate the level of seal oil in the oil pot 88. The top of the oil pct 68 is provided with a filler cap 90 and is connected by line 12 to the double check valve unit 83 described hereinbefore. The unit 83 may be connected to the compressor outlet 21 by line 86 for the pur pose of maintaining compressor outlet pressure on the seal oil in chamber 53.

The operation of the systems disclosed will now be described. Low pressure gaseous refrigerant from the evaporators II and I2 is compressed in compressors [5 or 16, cooled in condenser i8, and the liquid refrigerant collected in receiver l3 from which it is circulated back to the evaporators II or [2. In order to boost the refrigeration capacity of this closed system, the rotary vane type compressor 20 is connected in the gaseous refrigerant line between the evaporator l2 and the compressor l5. The booster compressor 20, in a typical installation, may compress the gaseous refrigerant, such as ammonia gas, to pressures of the order of thirty-five pounds per square inch and the high stage compressors l5 and It increase this intermediate pressure to a pressure of the order of one hundred and eighty-five pounds per square inch. The compressed gaseous refrigerant from the booster compressor 20 may be cooled by the intercooler 2| before it reaches the high stage compressors l5 and IS. The rotary vane compressor 20 is cooled by the circulation of a suitable anti-freeze liquid, such as oil, through the

jacket passages

45, 48, 49, and 50, by means of pump 60. The heat in the cooling liquid flowing from the compressor jackets may be dissipated in the coil 22 located in the floor of the evaporator chamber or refrigerated space; or, it may b dissipated in the cooler 6|. The cooling liquid from outlet 46 then passes back to the jacket inlet 41 by

lines

62 and 64, an expansion tank 63 being connected in the line. In the Figure 5 modification, the cooling liquid from outlet 45 passes through line 56 to the sealing cooling jacket 50 and then through line 51 to the cooler 6 l pump 68, and inlet 41. The double seal 31-38 on the drive shaft 34 of the booster compressor 20 is cooled by the cooling liquid in the passage 59. A sealing liquid such as oil is supplied to the space 53 between the

seals

31 and 38 and is maintained at a pressure about equal to the compressor outlet pressure to prevent air from leaking into the compressor during operation and to prevent refrigerant gas from leaking out through the seal 31 during stand-by. The sealing liquid pressure is maintained by the equalizing check valve unit 83, and where the sealing liquid is externally cooled it is circulated by pump 66 for cooling in the oil pct 69 or by the coil 14 on the compressor inlet line 15. Both the cooling liquid circuit and the sealing liquid circuit are closed circuits, and these circuits are independent of each other. The pressure in the sealing liquid circuit is automatically controlled by the pressure existing in the compressor outlet, and may be held at a limited positive pressure during compressor operation as well as during standby. The maintenance of positive pressure on the sealing liquid during standby is particularly important when two or more rotary compressors 20 are operated in parallel and one is shut down, because a vacuum condition could exist throughout a compressor and air might leak through the sealinto the refrigerant in the compressor except as the oil pressure seal is maintained. The circulation of coolingjacket liquid through coils in the floor of a low temperature storag room, thus protecting the earth under the floor from freezing and buckling the floor, is an advantageous economy since the need for cooling water is avoided and the need for a separate source of heat to warm floor piping is also avoided.

The present invention contemplates the use of various forms of rotary compressors, pumps, heat exchangers, valves, automatic controls, etc, as it will be readily apparent to the skilled refrigeration engineer that many such variations are possible within the scope of the following claims.

I claim:

1. A system for cooling and sealing a rotary type refrigerant gas compressor in which a liquid coolant is circulated in a closed circuit which includes a jacket surrounding the compressor and a jacket which surrounds the sealing means for the driven end of the compressor shaft, comprising: pump means for circulating the liquid coolant in both of said jackets; housing means for containing a liquid sealing medium in confined contact with the driven end of the compressor shaft; and pressure communicating means connected with the compressor outlet for maintaining pressure equal to compressor outlet pressure on th said sealing medium.

2. A system for cooling and sealing a rotary type refrigerant gas compressor in which a liquid coolant is circulated in a closed circuit which includes a jacket surrounding the compressor and a jacket which surrounds the sealing means for the driven end of the compressor shaft, comprising: means for circulating the coolant in both of said jackets, said means including a circulating pump and a heat exchanger for dissipating heat from said coolant; housing means for containing a liquid sealing medium in confined contact with the driven end of the compressor shaft; and pressure communicating means connected with the compressor outlet for maintaining compressor outlet pressure on the said sealing medium.

3. A system for cooling and sealing a rotary type refrigerant gas compressor in which a coolant is circulated in a closed circuit which includes a jacket a jacket which surrounds the sealing means for the driven end of the compressor shaft, comprising: means for circulating the coolant in both of said jackets, said means including a circulating pump and a heat dissipating coil associated with the floor of a refrigerated chamber; housing means for containing a liquid sealing medium in confined contact with the driven end of the compressor shaft; and means connected with the compressor outlet for maintaining compressor outlet pressure on the said sealing medium.

4. A system for cooling and sealing a rotary type refrigerant gas compressor in which a liquid coolant is circulated in a closed circuit which includes a jacket surrounding the compressor and a jacket which surrounds the sealing means for the driven end of the compressor shaft, comprisingz means for circulating the coolant through both of said jackets; a closed sealing medium circuit for circulating a liquid sealing medium into contact with the driven end of the compressor shaft, said circuit including a circulating pump, a heat exchanger, and a pressure communicating connection with the compressor outlet for maintaining a pressure on the sealing surrounding the compressor and r lit medium in contact with said compressor shaft as high as the normal outlet pressure of said compressor.

5. A system for cooling and sealing a rotary type refrigerant gas compressor in which a liquid coolant is circulated in a closed circuit which ineludes a jacket surrounding the compressor and a jacket which surrounds the sealing means for the driven end of the compressor shaft, comprising: a closed coolant circuit including a circulating pump and a heat exchanger connected for circulating the coolant in both of said jackets; a closed sealing medium circuit including a circulating pump and a heat exchanger connected for circulating a sealing liquid in confined contact with the driven end of said compressor shaft; and a pressure communicating connection between said sealing medium circuit and the outlet of said compressor for maintaining a pressure on the sealing medium in contact with said shaft at least as high as the compressor outlet pressure.

6. A cooling and sealing system as recited in claim 5 in which said pressure communicating connection includes a check valve.

7. A cooling and sealing system as recited in claim 5 in which said connection includes two valves maintaining compressor outlet pressure on said sealing medium, the other of said valves relieving excess pressure on said sealing valve into said compressor outlet.

8. A booster compressor stage for a closed refrigeration system, said stage comprising a refrigerant gas compressor in which a liquid coolant is circulated in a closed circuit which includes a jacket surrounding the compressor and a jacket which surrounds sealing means for the driven end of the compressor shaft, means for circulating the coolant in both of said jackets, housing means for containing a liquid sealing medium in confined contact with the driven end of the compressor shaft, and means connected with the compressor outlet for maintaining pressure on said sealing medium.

9. A booster compressor stage for a closed refrigeration system, said stage comprising a rotary refrigerant gas compressor in which a liquid coolant is circulated in a closed circuit which includes a. jacket surrounding the compressor and a jacket which surrounds sealing means for the driven end of the compressor shaft, said circuit including a circulating pump and a heat exchanger for dissipating heat from said coolant, housing means for containing a liquid sealing medium in confined contact with the driven end of said compressor shaft, and pressure communicating means including a check valve connected with the compressor outlet for maintaining a pressure on said sealing medium.

10. A booster compressor stage for refrigeration systems, said stage comprising: a rotary vane-type compressor for gaseous refrigerant, said compressor having a suction line and a discharge line connected thereto and adapted to be connected in a refrigeration system, said compressor having a surrounding jacket for coolant circulation; a rotary drive shaft projecting from said compressor; a pair of packing members spaced apart on said shaft; a casing secured to said compressor surrounding said packing members and said drive shaft and having a surrounding jacket; a closed coolant circuit including a circulating pump and a heat exchanger connected to circulate a coolant through both of said jackets; a closed sealing medium circuit including a circulating pump and a heat exchanger connected to circulate a sealing medium through said casing between said packing members; and a pressure communicating connection between said compressor discharge line and said sealing medium circuit for maintaining a pressure on said sealing medium substantially equal to said compressor outlet pressure.

References Cited in the file of this patent UNITED STATES PATENTS Number Number Number Name Date Heim et al Apr. 6, 1897 Carrey Jan. 4, 1921 Cuthbert Oct. 15, 1929 Steiner Apr. 25, 1933 Baumenn Nov. 6, 1934 FOREIGN PATENTS Country Date Germany Sept. 26, 1940