US3296823A

US3296823A - Absorption refrigerating system having pump means circulating absorbent and refrigerant

Info

Publication number: US3296823A
Application number: US464359A
Authority: US
Inventors: Robert P Novak; James M Porter
Original assignee: Trane Co
Current assignee: Trane US Inc
Priority date: 1965-06-16
Filing date: 1965-06-16
Publication date: 1967-01-10
Anticipated expiration: 1984-01-10
Also published as: CH513375A; DE1501151A1; GB1084663A

Description

Jan. 10, 1967 R. P. NOVAK ETAL ABSORPTION REFRIGERATING SYSTEM HAVING PUMP MEANS CIRCULATING ABSORBENT AND REFRIGERANT Filed June 16, 1965 5 Sheets-Sheet l ATTORNEYS Jan. 10, 1967 ov ETAL 3,296,823

ABSORPTION REFRIGERATING SYSTEM HAVING PUMP MEANS GIRCULATING ABSORBENT AND REFRIGERANT Filed June 16, 1965 5 Sheets-Sheet 2 FIGS 1N VEN'IURS ROBERT P. NOVAK JAMES M. PORTER AT TOR NEYS Jan. 10, 1967 R. P. NOVAK ETAL 3,296,823

ABSORPTION REFRIGERATING SYSTEM HAVING PUMP MEANS CIRCULATING ABSORBENT AND REFRIGERANT Filed June 16, 1965 5 Sheets-Sheet s I N V EN '1 0R8 ROBERT P. NOVAK JAMES M. PORTER 7 m? v QMM ATTORNEYS States Patent @flice 3,296,823 Patented Jan. 10, 1967 3,296,823 ABSORPTION REFRIGERATENG SYSTEM HAVllN G PUMP MEANS CHRCULATTNG ABSORBENT AND REFRIGERANT Robert P. Novak, Mindoro, and James M. Porter, La Crosse, Wis, assignors to The Trane Company, La Crosse, Wis, a corporation of Wisconsin Filed June 16, 1965, Scr. No. 464,359 8 Claims. (Cl. 62-476) This invention relates to absorption refrigerating systems and more particularly to an absorption refrigerating system including pump means for circulating fluids in the system. In general, systems of this type have interior spaces which are less than atmospheric pressure during operation. It is desirable to avoid the use of running seals between the interior of the pump and the atmosphere, because such seals often permit air to enter the system in spite of attempts to design seals to prevent leakage. The presence of air in the system results in reduced efliciency and the air must be removed by a purge system.

The use in an absorption refrigerating system of hermetically sealed pumps has been shown in US. Patent No. 2,983,117 issued to P. Edberg et al. However in such systems, there is some danger of overheating the solution pump motors in the event of failure of the evaporator pump which supplies refrigerant for lubricating and cooling these motors.

It is therefore an object of this invention to provide a pump for pumping a plurality of fluids in which the pump is driven by a single motor.

It is another object of this invention to provide a motor driven pump for pumping a plurality of fluids in which one of the fluids pumped is circulated to cool and lubricate the motor and the pump.

It is another object of the invention to provide a pump and a driving motor secured in hermetically sealed relationship with each other.

It is another object of this invention to provide a pump having a rotating seal between the pump and the motor to permit removal of the motor without opening the pump or the absorption system to the atmosphere.

It is another object of the invention to provide a pump having solution impellers in back-to-back relationship at one end and a refrigerant impeller at the other end with a driving motor at the end having the refrigerant impeller so that if there is leakage into the motor the fluid leaked will berefrigerant and not absorbent solution which could cause corrosion in the motor.

It is another object of the invention to reduce the thrust forces of the pump shaft by mounting the solution pumps in back-to-back relationship and providing a balancing piston eifect on the evaporator pump so that there is a reduced thrust of the pump shaft on the motor shaft.

It is another object of the invention to provide a thrust bearing on the motor shaft to absorb the combined thrust of the pump shaft and the motor shaft.

It is another object of the invention to provide means for lubricating and cooling the pump and the motor from a fluid source separate from the absorption machine.

Other objects and advantages of this invention will become apparent as the specification proceeds to describe the invention with reference to the accompanying drawing in which:

FIGURE 1 is a diagrammatic sectional view of the absorption refrigerating system including the fluid circulating system;

FIGURE 2 is an end view of the pump;

FIGURE 3 is a sectional view taken on line 3--3 of FIGURE 2; and

FIGURE 4 is a longitudinal sectional view of the motor taken on line 3-3 of FIGURE 2.

Referring now to FIGURE 1, the absorption system shown is of the type having a single shell 10, a partition 11 separating a high pressure chamber containing a condenser 12 and a generator 14 from a low pressure chamber containing an evaporator 16 and an absorber 18. It should be understood that other arrangements might be used; for instance, the generator 14 and the condenser 12 might be in one shell and the absorber 18 and the evaporator 16 might be in a second shell with conduits therebetween for conducting fluids.

Various combinations of refrigerant and absorbent may be used. A solution of lithium bromide and water has been found to be highly satisfactorily for use.

The absorber 18 has a coil 20 supplied with cooling fluid from a source 22 to remove the heat from the absorber. This cooling fluid is conducted by a conduit 24 to a cooling coil 26 in the condenser 12 and the cooling fluid leaves the machine through a conduit 28. The cooling coil 26 in the condenser 12 removes the heat from and condenses the refrigerant vapor in the condenser.

The generator 14 has a heating coil 3t supplied with heating fluid from a source 32. The heating fluid is discharged from the coil 3th through a conduit 34. The coil 3i heats the absorbent solution in the generator 14 causing it to boil and force refrigerant vapor into the condenser 12. The condensed refrigerant in the condenser 12 flows through an opening 36 into the evaporator 16. The absorbent solution in the absorber 18 reduces the pressure in the absorber i8 and in the evaporator 16 by the absorption of refrigerant vapor, thus causing the refrigerant in the evaporator 16 to boil. A low temperature is thus maintained in the evaporator 16.

Evaporator 16 has a coil 37. Fluid from a refrigerating load such as an air conditioning system enters coil 37 through a conduit 38. This fluid is reduced in temperature in the coil 37 and returns to the refrigerating load through conduit 39.

The liquid refrigerant in the evaporator 16 flows through a conduit 40 to a sump 41 and thence through conduit 42 to a pump indicated generally by numeral 43. Pump 43 is driven by a motor indicated generally by numeral 44. The liquid refrigerant is discharged by pump 43 through conduit 45 from which it flows through nozzles 46 into the evaporator 16.

Dilute solution flows from absorber 18 through conduit 48 to pump 43. The dilute solution is discharged by pump 43 through conduit 50 which conducts the dilute solution to heat exchanger 52 from which it flows through conduit 54 to the generator 14.

Concentrated solution flows from the generator 14 through conduit 56 and thence through heat exchanger 52 from which it flows through conduit 58 to conduit 60.

Dilute solution flows from absorber 18 through conduit 62 and thence into conduit 60 to form, with the solution from conduit 58, a solution of intermediate concentration which enters the pump 43 and is discharged thereby through conduit 62 which discharges the intermediate solution into the absorber through nozzles 63.

Pump 43 has a pump body 64. A hearing housing 65 having a bearing 66 is mounted on the body 64 at one end and a bearing housing 67 having a bearing 68 is mounted on the pump body 64 at its other end. Bearings 66 and 68 have helical grooves 69 and '70 respectively for conducting the liquid which lubricates and cools the bearings. A shaft 72 is rotatably mounted in the bearings 66 and 68.

A refrigerant impeller 73 is mounted on shaft 72 to rotate therewith. Pump 43 has an inlet passageway '74 in fluid flow communication with conduit 42 and impeller 73. A discharge passageway 75 is in fluid flow communication with impeller 73 and conduit 45. Impeller 73 has holes 76 which conduct refrigerant from a chamber 71 at 3 the back side of the impeller to provide a balancing piston effect and reduce the thrust of impeller 73 during operation.

An impeller 77 is mounted on shaft 72 to rotate therewith. Pump 43 has an inlet passageway 78 in fluid flow communication with conduit 60 and impeller 77. A discharge passageway 79 is in fiuid flow communication with impeller 77 and conduit 62.

An impeller 80 is mounted on shaft 72 to rotate therewith. Pump 43 has an inlet passageway 82 in fluid flow communication with conduit 48 and impeller 80. A discharge passageway 83 is in fluid flow communication with impeller 80 and conduit 50.

A rotating seal 84 is mounted on shaft 72 to prevent leakage between bearing housing 65 and inlet passageway 78.

A rotating seal 86 is mounted on shaft 72 to prevent leakage between chamber 71 and inlet passageway 82.

A rotating seal 88 is mounted on shaft 72 to prevent leakage between bearing housing 67 and inlet passageway 74.

The motor 44 has a frame comprising casing 89 and

bearing housings

90 and 93. Bearing housing 90 has a bearing 92 and bearing housing 93 has a bearing 94, A shaft 95 is rotatably mounted in

bearings

92 and 94. A drive coupling 91 is secured to pump shaft 72 and is in splined engagement with motor shaft 95. A thrust hearing member 96 is mounted on shaft 95 and is supported by the bearing housing 93. The thrust bearing 96 is of the well known Kingsbury type having pivoted shoes. A motor rotor 97 is mounted on shaft 95 within a motor stator 98.

For conducting refrigerant liquid to the pump 43 and motor 44 for cooling and lubricating these parts, a conduit 99 extends from the discharge passageway 75. The refrigerant liquid flows through conduit 101 to motor 44. The refrigerant liquid then flows through a helical groove 102 in bearing 94, thence through thrust bearing 96 and then through the gap 103 between rotor 97 and stator 98. From the gap 103 the fluid flows through a helical groove 104 in bearing 92 and into the space 105 between bearing housings 67 and 90. Some refrigerant liquid flows through helical groove 70 in bearing 68. From space 105 the refrigerant liquid flows through

conduits

106 and 107 to the inlet chamber 74 and of the pump 43.

Refrigerant liquid from conduit 99 also'flows through conduit 108 to conduit 109 and thence to the helical groove 69 of bearing 66. From bearing 66 the liquid flows through conduit 110 and thence through conduit 111 to conduit 107 from which it flows to inlet chamber 74 of pump 43.

There may be times when there is insufiicient refrigerant for lubricating and cooling pump 43 and motor 44. For this reason, provision is made for using an external source of water such as city water for cooling and lubricating the pumps. In order to accomplish this, we provide a valve 112 in conduit 99 and a valve 113 in conduit 107 to shut off the flow in these conduits. Valve 114 is connected to a pressurized source of water external to the system and valve 115 controls the return flow to the source or to waste.

When it is desired to operate the machine using an external source of water for lubricating and cooling the pump 43 and the motor 44, valves 112 and 113 are closed and

valves

114 and 115 are opened. The flow is then as indicated by the dash line arrows. From valve 114 a portion of the flow is through conduit 109 to hearing 66 and then through conduit 110 and valve 115. The other portion of the flow from valve 114 is successively through

conduits

108, 101, motor 44, conduits 106, 111 and valve 115.

The uppermost portions of

discharge chambers

79 and 83 are provided with hand valves 116 and 117 respectively. During operation of the system these valves are in closed position. However when it is desired to open pump 43 to service the interior parts, valves 116 and 117 may be opened to allow air to enter the pump and displace absorbent solution in the pump.

It is to be noted that impellers 77 and have equal outside diameters at the inlet and the discharge. This simplifies the machining of the housing and it makes it possible to remove these impellers 77 and 80 from the housing by removing the bearing housing 65. The impellers 77 and 80 may be removed without removing the shaft 72.

Impeller 73 is similarly constructed, and it can be removed by first removing the motor 44 and the bearing housing 67,

Although we have described specific embodiments of our invention, we contemplate that various modifications may be made without departing from the scope or spirit of our invention and we desire to be limited only by the claims.

We claim:

1. In an absorption refrigerating system having a refrigerant and an absorbent, the combination of an absorber, an evaporator, a generator, a condenser and a pump to circulate refrigerant and absorbent in said system, said pump having a shaft rotatably mounted therein, a motor drivingly connected to said shaft, a first impeller mounted on said shaft, conduit for conducting absorbent from said absorber to the inlet of said first impeller, conduit for conducting absorbent from the outlet of said first impeller to said generator, a second impeller mounted on said shaft in adjacent back-to-back relationship with said first impeller, conduit for conducting absorbent from a first portion of said absorber to the inlet of said second impeller, conduit for conducting absorbent from the outlet of said second impeller to a second portion of the absorber, a third impeller mounted on said shaft, conduit for conducting refrigerant from a first portion of the evaporator to the inlet of said third impeller and conduit for conducting refrigerant from the outlet of said third impeller to a second portion of the evaporator.

2. In an absorption refrigerating system having a refrigerant and an absorbent, the combination of an absorber, an evaporator, a generator, a condenser, and a pump to circulate refrigerant and absorbent in said system, said pump having a shaft rotatably mounted therein, a motor drivingly connected to said shaft, a first impeller mounted on said shaft, conduit for conducting absorbent from said absorber to the inlet of said first impeller, conduit for conducting absorbent from the outlet of said first impeller to said generator, a second impeller mounted on said shaft in adjacent back-to-back relationship with said first impeller, conduit for conducting absorbent from a first portion of said absorber to the inlet of said second impeller, conduit for conducting absorbent from the outlet of said second impeller to a second portion of the absorber, a third impeller mounted on said shaft, conduit for conducting refrigerant from a first portion of the evaporator to the inlet of said third impeller, and conduit for conducting refrigerant from the outlet of said third impeller to a second portion of said evaporator, said third impeller having means for conducting refrigerant from the back of said third impeller to the inlet of said third impeller to reduce the thrust of said third impeller.

3. In an absorption refrigerating system having a refrigerant and an absorbent, the combination of an absorber, an evaporator, a generator, a condenser and a pump to circulate refrigerant and absorbent in said system, said pump comprising an elongated body, a pump shaft, bearings in said body adjacent opposite ends thereof for rotatably supporting said pump shaft in said body, a first centrifugal impeller mounted on said shaft adjacent one end of said body, conduit for conducting absorbent from said absorber to the inlet of said first impeller, conduit for conducting absorbent from the outlet of said first impeller to said generator, a second centrifugal impeller mounted on said pump shaft in adjacent back-to-back relationship with said first impeller, conduit for conducting absorbent from a first portion of said absorber to the inlet of said second impeller, conduit for conducting absorbent from the outlet of said second impeller to a second portion of said absorber, a third impeller mounted on said shaft adjacent the other end of said body from said first end, conduit for conducting refrigerant from a first portion of said evaporator to the inlet of said third impeller and conduit for conducting refrigerant from the outlet of said third impeller to a second portion of said evaporator, a motor frame secured to said other end of said pump body, a motor shaft, means rotatably mounting said motor shaft on said motor frame, a thrust bearing on said motor frame for axially supporting said motor shaft, means coupling said pump shaft to said motor shaft for driving said pump shaft from said motor shaft and means on said pump shaft and said motor shaft for transferring the thrust of said pump shaft to said motor shaft.

4. In an absorption refrigerating system according to claim 3 in which the outlet of said third impeller is arranged longitudinally of said body between the inlet of said third impeller and the outlet of said second impeller, means for conducting refrigerant from the back of said third impeller to the inlet of said third impeller to reduce the thrust of said third impeller.

5. In an absorption refrigerating system having a refrigerant and an absorbent, the combination of an absorber, an evaporator, a generator, a condenser and a pump to circulate refrigerant and absorbent in said system, said pump comprising an elongated body, a pump shaft, a first shaft bearing adjacent one end of said body for rotatably supporting said pump shaft in said body, a first centrifugal impeller mounted on said shaft adjacent said first shaft bearing, a second impeller mounted on said shaft adjacent said first impeller, first conduit for conducting absorbent from said absorber to the inlet of one of said first and second impellers and from the outlet of said one of said first and second impellers to said generator, second conduit for conducting absorbent from a first portion of said absorber to the inlet of the second of said first and second impellers, and from the outlet of said second of said first and second impellers to a second portion of said absorber, a third centrifugal impeller mounted on said shaft, third conduit for conducting refrigerant from a first portion of the evaporator to the inlet of said third impeller, and fourth conduit for conducting refrigerant from the outlet of said third centrifugal impeller to a second portion of said evaporator, a second shaft bearing adjacent the other end of said body, a motor frame secured to said other end of said body, a motor shaft, motor bearings rotatably mounting said motor shaft on said motor frame, a thrust bearing on said motor frame for axially supporting said motor shaft, means coupling said pump shaft to said motor shaft for driving said pump shaft from said motor shaft, means on said pump shaft and said motor shaft for transferring the thrust of said pump shaft to said motor shaft, and a rotating seal on said pump shaft between the third conduit and said second shaft bearing.

6. In an absorption refrigeration system having a refrigerant and absorbents, the combination of an absorber, an evaporator, a condenser, a generator and a pump in a closed system, said pump comprising an elongated body, a pump shaft, a first shaft bearing adjacent one end of said body for rotatably supporting said pump shaft in said body, said body having adjacent said one end of a first inlet passageway and a first discharge passageway, a first centrifugal impeller mounted on said pump shaft in fluid communication with said first inlet passageway and said first discharge passageway for circulating a first absorbent, said body having a second inlet passageway and a second discharge passageway, a second centrifugal impeller mounted on said pump shaft in fluid communication with said second inlet passageway and said second discharge passageway for circulating a second absorbent, said body having at the other end from said one end a third inlet passageway and a third discharge passageway for refrigerant, a third centrifugal impeller mounted on said pump shaft in fluid communication with said third inlet passageway and said third discharge passageway for circulating refrigerant, a second shaft bearing adjacent said other end of said body, a motor frame secured to said other end of said pump body, a motor shaft, motor bearings rotatably mounting said motor shaft on said motor frame, a thrust bearing on said motor frame for axially supporting said motor shaft, means coupling said pump shaft to said motor shaft for driving said pump shaft from said motor shaft, means on said pump shaft and said motor shaft for transferring the thrust of said pump shaft to said motor shaft, means for conducting water from a source exterior to said system over said motor bearings, said thrust bearing and said first and second bearings to cool and lubricate the same.

7. In an absorption refrigeration system having a refrigerant and absorbents, the combination of an absorber, an evaporator, a condenser, a generator and a pump in a closed system, said pump comprising an elongated body, a pump shaft, pump shaft bearing means for rotatably supporting said pump shaft in said body, said body having a first inlet passageway and a first discharge passageway, a first centrifugal impeller mounted on said pump shaft in fluid communication with said first inlet passageway and said first discharge passageway for circulating a first absorbent, said body having a second inlet passageway and a second discharge passageway, a second centrifugal impeller mounted on said pump shaft in fluid communication with said second inlet passageway and said second discharge passageway for circulating a second absorbent, said body having a third inlet passageway and a third discharge passageway, a third centrifugal impeller mounted on said pump shaft in fluid communication with said third inlet passageway and said third discharge passageway for circulating refrigerant, a motor frame secured to said pump body, a motor shaft, motor bearing means rotatably mounting said motor shaft on said motor frame, means drivingly connecting said pump shaft to said motor shaft for driving said pump shaft from said motor shaft and means for conducting refrigerant over said pump shaft bearing means and said motor bearing means to cool and lubricate the same.

8. In an absorption refrigeration system having a refrigerant and absorbents, the combination of an absorber, an evaporator, a condenser, a generator and a pump in a closed system, said pump comprising an elongated body, a pump shaft, a first shaft bearing adjacent one end of said body for rotatably supporting said pump shaft in said body, said body having adjacent said one end a first inlet passageway and a first discharge passageway, a first centrifugal impeller mounted on said pump shaft in fluid communication with said first inlet passageway and said first discharge passageway for circulating a first absorbent, said body having a second inlet passageway and a second discharge passageway, a second centrifugal impeller mounted on said pump shaft in fluid communication with said second inlet passageway and said second discharge passageway for circulating a second absorbent, said body having at the other end from said one end a third inlet passageway and a third discharge passageway for refrigerant, a third centrifugal impeller mounted on said pump shaft in fluid communication with said third inlet passageway and said third discharge passageway for circulating refrigerant, a second shaft bearing adjacent said other end of said body, a motor frame secured to said other end of said pump body, a motor shaft, motor bearing means rotatably mounting said motor shaft on said motor frame, a thrust bearing on said motor frame for axially supporting said motor shaft, means coupling said pump shaft to said motor shaft for driving said pump shaft from said motor shaft, means on said pump shaft and said motor shaft for transferring the thrust of said pump shaft to said motor shaft, means for conducting refrigerant from said third impeller over said motor bearing means, said thrust bearing and said first and second bearings and back to said third inlet passageway to cool and lubricate said motor bearing means, said thrust bear ing, and said first and second bearings.

References Cited by the Examiner UNITED STATES PATENTS LLOYD L. KING, Primary Examiner.

Claims

1. IN AN ABSORPTION REFRIGERATING SYSTEM HAVING A REFRIGERANT AND AN ABSORBENT, THE COMBINATION OF AN ABSORBER, AN EVAPORATOR, A GENERATOR, A CONDENSER AND A PUMP TO CIRCULATE REFRIGERANT AND ABSORBENT IN SAID SYSTEM, SAID PUMP HAVING A SHAFT ROTATABLY MOUNTED THEREIN, A MOTOR DRIVINGLY CONNECTED TO SAIDSHAFT, A FIRST IMPELLER MOUNTED ON SAID SHAFT, CONDUIT FOR CONDUCTING ABSORBENT FROM SAID ABSORBER TO THE INLET OF SAID FIRST IMPELLER, CONDUIT FOR CONDUCTING ABSORBENT FROM THE OUTLET OF SAID FIRST IMPELLER TO SAID GENERATOR, A SECOND IMPELLER MOUNTED ON SAID SHAFT IN ADJACENT BACK-TO-BACK RELATIONSHIP WITH SAID FIRST IMPELLER, CONDUIT FOR CONDUCTING ABSORBENT FROM A FIRST PORTION OF SAID ABSORBER TO THE INLET OF SAID SECOND IMPELLER, CONDUIT FOR CONDUCTING ABSORBENT FROM THE OUTLET OF SAID SECOND IMPELLER TO A SECOND PORTION OF THE ABSORBER, A THIRD IMPELLER MOUNTED ON SAID SHAFT, CONDUIT FOR CONDUCTING REFRIGERANT FROM A FIRST PORTION OF THE EVAPORATOR TO THE INLET OF SAID THIRD IMPELLER AND CONDUIT FOR CONDUCTING REFRIGERANT FROM THE OUTLET OF SAID THIRD IMPELLER TO A SECOND PORTION OF THE EVAPORATOR.