Refrigeration – Refrigeration producer – Sorbent type
Reexamination Certificate
2000-07-18
2001-05-22
McDermott, Corrine (Department: 3744)
Refrigeration
Refrigeration producer
Sorbent type
C062S335000, C062S141000
Reexamination Certificate
active
06233968
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an absorption refrigerating machine, and more particularly, to an absorption refrigerating machine having a large pumping-up temperature difference and an absorption refrigerating machine suitable for low temperature generation of not more than 0° C.
An example of an absorption refrigerating machine having a large pumping-up temperature difference and an absorption refrigerating machine capable of producing a low temperature under 0° C., is disclosed in JP-A-7-139844. In this prior art, evaporators and absorbers are arranged in a two-stage manner so that the pumping-up temperature difference from the low temperature side to the high temperature side can be made large. And besides, an absorbent is mixed into a refrigerant to lower the solidifying point of the refrigerant. With this construction, the evaporation of the refrigerant becomes possible also in the temperature under 0° C. and low temperature generation becomes possible.
In the construction disclosed in this prior art publication, since two sets of evaporators and absorbers are used, evaporation heat-transfer surface and absorption heat-transfer surface respectively become double. Therefore, the number of heat-transfer pipes or the number of heat-transfer plates increase, which leads to a disadvantage that the cost increases.
The above prior art publication also discloses an example in which one evaporator comprises a flash evaporator, and refrigerant, cooled by this evaporator, cools an absorber, and with this construction the number of heat-transfer pipes is reduced. In this case, however, the power of a refrigerant pump is increased.
And besides, although the concentration of mixed refrigerant is varied in accordance with the generating temperature, liquid refrigerant is caused to flow to a solution side without being evaporated, and therefore the refrigerant is used inefficiently. This leads to a disadvantage that the overall efficiency is lowered.
SUMMARY OF THE INVENTION
It is an object of the present invention to achieve a low-cost design by reducing the heat-transfer surfaces and the number of pumps in an absorption refrigerating machine in which a pumping-up temperature difference is large and a low temperature can be produced.
Another object of the present invention is to achieve high efficiency by reducing an amount (proportion) of flowing of liquid refrigerant to solution side so as to eliminate the inefficient use of the refrigerant when adjusting the concentration of mixed refrigerant in an absorption refrigerating machine in which a pumping-up temperature difference is large and a low temperature can be produced.
A first characteristic feature of the present invention to achieve the above objects resides in an absorption refrigerating machine comprising a low-temperature evaporator and a high-temperature evaporator which are arranged in a two-stage manner; and a low-temperature absorber and a high-temperature absorber which are arranged in a two-stage manner; wherein the low-temperature absorber comprises a spray absorber, and a solution, raised in temperature by absorbing a refrigerant in the low-temperature absorber, is fed to the high-temperature evaporator to be cooled, and the cooled solution is sprayed in the low-temperature absorber.
A second characteristic feature of the present invention to achieve the above objects resides in an absorption refrigerating machine comprising a regenerator for heating an absorption solution; a condenser for condensing the refrigerant fed from the regenerator; a first evaporator for vaporizing the refrigerant condensed by the condenser, the first evaporator having a heat-transfer pipe provided therein, through which pipe a fluid to be cooled flows; a second evaporator having a heat-transfer pipe through which chilled water or brine flows; a first absorber for causing the refrigerant, vaporized in the first evaporator, to be absorbed by a solution, the first absorber having a first solution pump; and a second absorber which has a second solution pump and a spray device, and causes the refrigerant, vaporized in the second evaporator, to be absorbed by the absorption solution, and supplies the absorption solution, having absorbed the refrigerant, to the spray device by the use of the second solution pump; wherein there is provided a pipe for feeding the absorption solution in the second absorber to the heat-transfer pipe in the first evaporator.
Preferably, the first evaporator comprises a refrigerant sprinkling device for sprinkling the liquid refrigerant, and refrigerant-collecting means provided at a lower portion thereof for collecting that portion of the sprinkled refrigerant which has not vaporized, and the second evaporator comprises a refrigerant tank provided at a lower portion thereof for storing the refrigerant, and the refrigerant-collecting means of the first evaporator is communicated with the refrigerant tank of the second evaporator.
Preferably, the refrigerant tank of the second evaporator is disposed at a level below the refrigerant-collecting means of the first evaporator.
It is desirable that the condenser has a liquid refrigerant-collecting portion provided at a lower portion thereof, and the liquid refrigerant-collecting portion is communicated with the refrigerant sprinkling device of the first evaporator, and there is provided solution mixing means for supplying the absorption solution in the second absorber to the refrigerant in the second evaporator.
Preferably, there is provided solution mixing means for supplying the absorption solution in the first absorber or the second absorber to the refrigerant in the second evaporator. Alternatively, it is preferable to provide refrigerant outflow means for feeding the liquid refrigerant in the second evaporator to the second absorber or a suction side of the second solution pump.
Further, it is preferable to provide (a) refrigerant outflow means, which comprises a pipe, communicating the refrigerant tank of the second evaporator with the second absorber or the suction side of the second solution pump, and a first control valve provided in the pipe, (b) second sprinkling means for sprinkling the mixed solution in the second evaporator, (c) concentration detection means for detecting the concentration of the mixed solution supplied to the second sprinkling means by the second refrigerant pump, and (d) a control device for controlling an amount of at least refrigerant and solution flowing in or flowing out from the second evaporator; and the solution mixing means comprises an absorption solution pipe for feeding the absorption solution in the second absorber to the second evaporator and a second control valve provided in the absorption solution pipe, and the control device controls the first and second control valves in accordance with a concentration signal detected by the concentration detection means.
Further, it is preferable that the first evaporator comprises refrigerant sprinkling means for sprinkling the liquid refrigerant, refrigerant-collecting means provided at a lower portion thereof for collecting that portion of the sprinkled refrigerant which has not vaporized and a first refrigerant pump for feeding the refrigerant in the refrigerant-collecting means to the refrigerant sprinkling means, and the second evaporator comprises a refrigerant tank provided at a lower portion thereof for storing the refrigerant, and there are provided (a) solution mixing means for supplying the absorption solution in the first absorber or the second absorber to the second evaporator, (b) a refrigerant pipe for supplying the liquid refrigerant from the condenser to the first evaporator, (c) a connection pipe connecting a discharge side of the first refrigerant pump to the second refrigerant tank, (d) a third control valve provided in the connection pipe, (e) second sprinkling means for sprinkling the mixed solution in the second evaporator, (f) concentration detection means for detecting the concentration of the mixed solution fed to the second sprinkli
Aizawa Michihiko
Nishiguchi Akira
Ohuchi Tomihisa
Sakiyama Ryoko
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Jiang Chen-Wen
McDermott Corrine
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