GB2049905A

GB2049905A - Evaporator units of absorption refrigeration systems

Info

Publication number: GB2049905A
Application number: GB8014602A
Authority: GB
Original assignee: Tadiran Israel Electronics Industries Ltd
Current assignee: Tadiran Israel Electronics Industries Ltd
Priority date: 1979-05-16
Filing date: 1980-05-02
Publication date: 1980-12-31
Also published as: IL57306A0; DE3018503A1; IL57306A; IT1130424B; DE3018503C2; JPS55155149A; IT8022101A0; GB2049905B

Abstract

The present invention relates to an absorption refrigeration system of the type using water as refrigerant and aqueous lithium bromide and/or a similar compound as absorbant, wherein in addition to the conventional tubes of the evaporator there are provided tubes out of reach of the spray coming from the spray nozzles, said "dry" tubes being adapted to diminish carry-over of droplets to the absorber. A specific embodiment comprises a baffle substantially restricting the spray of water droplets in the evaporator to the conventional tubes. <IMAGE>

Description

SPECIFICATION Evaporators The present invention relates to an improvement in evaporators. in chillers of the type using water as refrigerant and aqueous lithium bromide as absorbantfor water vapor.

Water is sprayed as refrigerant in the evaporator, and water vapor is passed from the evaporator into the absorber. The entry of water droplets from the evaporator into the absorber is undesirable, and various means have been suggested to suppress such entry. One of the common means used is a mist eliminator but this involves both undesirable pressure drop and high cost. Another possibility is to resort to quite low flow velocities of the water vapor moving from the evaporator to the absorber, but this results in excessive dimensions of the evaporator. The present invention overcomes these drawbacks to a large extent.

According to the present invention baffle means are provided in the upper part of the evaporator where the tubes are located in the vicinity of which the liquid refrigerant is introduced, said baffles being adapted to prevent carry-over of water droplets to the absorber, confining the spray to a large extent to the evaporator tubes. Furthermore, according to the present invention there is provided one or more rows of "dry" tubes as outer rows. This arrangement prevents droplets blown off the evaporator tubes from being carried to the absorber. Drops blown off the evaporator tubes have to pass through the row of the dry tubes, where they are intercepted and a large proportion of these wiil be evaporated.

The invention is illustrated with reference to the accompanying schematical drawing, which is not according to scale, and in which the Figure is an elevational schematical cross-sectional view through a housing of a chiller wherein both the absorber and the evaporator are located.

The housing 11 is subdivided by wall 12 into two sections 13 and 14, and housing the absorber, the other the evaporator, which communicate with each other at the upper part.

Water is sprayed by nozzles 1 5 onto the "wet" evaporator tubes 1 6. There is provided a baffle 1 7 which prevents spray droplets coming from the nozzles 15, being carried into the absorber section 1 3. Most of the droplets of water are evaporated by means of the liquid circuiating in the tubes 16, but some are not completely evaporated, and these tend to be carried to the evaporator. This is prevented to a large extent by the provision of "dry" tubes 18, which are located at the boundary of the "wet" tubes 16, adjacent partition 12 and preferably also at the other boundary of the "wet" tubes, as shown at the right hand side of the drawing.

Droplets blown off tubes 1 6 are intercepted by tubes 1 8 and a large part of these are either completely evaporated or agglomerated at the surface of the "dry" tubes 1 8. Thus practically only water vapor enters the absorber 13. Thus the problem of carry-over of droplets of water is largely overcome without any undue expense as regards equipment or impaired performance due to pressure drop.

1. A chiller of the type using water as refrigerant and aqueous lithium bromide and/or a similar compound as absorbant, wherein in addition to the conventional tubes of the evaporator there are provided tubes out of reach of the spray coming from the spray nozzles, said "dry" tubes adapted to diminish carry-over of droplets to the absorber.

2. A chiller according to claim 1, wherein the "dry" tubes are provided as additional row of tubes at the end of the region of tubes adjacent a partition between the evaporator and the absorber.

3. A chiller according to claim 1 or 2, wherein a baffle is provided substantially restricting the spray of water droplets in the evaporator to the conventional tubes.

4. A chiller of the type defined in claim 1, substantially as hereinbefore described and with reference to the drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Evaporators The present invention relates to an improvement in evaporators. in chillers of the type using water as refrigerant and aqueous lithium bromide as absorbantfor water vapor. Water is sprayed as refrigerant in the evaporator, and water vapor is passed from the evaporator into the absorber. The entry of water droplets from the evaporator into the absorber is undesirable, and various means have been suggested to suppress such entry. One of the common means used is a mist eliminator but this involves both undesirable pressure drop and high cost. Another possibility is to resort to quite low flow velocities of the water vapor moving from the evaporator to the absorber, but this results in excessive dimensions of the evaporator. The present invention overcomes these drawbacks to a large extent. According to the present invention baffle means are provided in the upper part of the evaporator where the tubes are located in the vicinity of which the liquid refrigerant is introduced, said baffles being adapted to prevent carry-over of water droplets to the absorber, confining the spray to a large extent to the evaporator tubes. Furthermore, according to the present invention there is provided one or more rows of "dry" tubes as outer rows. This arrangement prevents droplets blown off the evaporator tubes from being carried to the absorber. Drops blown off the evaporator tubes have to pass through the row of the dry tubes, where they are intercepted and a large proportion of these wiil be evaporated. The invention is illustrated with reference to the accompanying schematical drawing, which is not according to scale, and in which the Figure is an elevational schematical cross-sectional view through a housing of a chiller wherein both the absorber and the evaporator are located. The housing 11 is subdivided by wall 12 into two sections 13 and 14, and housing the absorber, the other the evaporator, which communicate with each other at the upper part. Water is sprayed by nozzles 1 5 onto the "wet" evaporator tubes 1 6. There is provided a baffle 1 7 which prevents spray droplets coming from the nozzles 15, being carried into the absorber section 1 3. Most of the droplets of water are evaporated by means of the liquid circuiating in the tubes 16, but some are not completely evaporated, and these tend to be carried to the evaporator. This is prevented to a large extent by the provision of "dry" tubes 18, which are located at the boundary of the "wet" tubes 16, adjacent partition 12 and preferably also at the other boundary of the "wet" tubes, as shown at the right hand side of the drawing. Droplets blown off tubes 1 6 are intercepted by tubes 1 8 and a large part of these are either completely evaporated or agglomerated at the surface of the "dry" tubes 1 8. Thus practically only water vapor enters the absorber 13. Thus the problem of carry-over of droplets of water is largely overcome without any undue expense as regards equipment or impaired performance due to pressure drop. CLAIMS