US3635040A

US3635040A - Ingredient water chiller apparatus

Info

Publication number: US3635040A
Application number: US19416A
Authority: US
Inventors: William F Morris Jr
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-03-13
Filing date: 1970-03-13
Publication date: 1972-01-18
Anticipated expiration: 1989-01-18

Abstract

A cooler unit for cooling ingredient water or other liquids, wherein the liquid may be used in processing foods by direct contact with the foods or edible liquids may be cooled. The cooler unit includes a generally cylindrical tank of shell-andtube construction having an array of 3-inch diameter stainless steel tubes and end chambers partitioned by baffles connecting the tubes in series circuit relation, all surfaces exposed to the ingredient liquid being stainless steel. Liquid refrigerant is supplied to the interior of the shell above the tube array to discharge in droplets over the outer tubes surfaces along their whole length.

Description

lies WT ilit orris, Jr.

[451 .lenwm INGREDIENT WATER CLER APPARATUS 22 Filed: Mnr. 13,11970 21 App1.No.: 19,416

2,324,615 7/1943 Damrow 165/117 X 2,123,021 7/1938 Phillips ..62/118 2,225,491 12/1940 Voorhees et al 62/512 X 2,016,056 10/1935 Small ..62/498 P 2,462,329 2/ 1949 Mojonnier ..62/512 X Primary Examiner-William F. ODea Assistant Examiner-P. D. Ferguson Attorney-Mason, Fenwick & Lawrence [57] ABSCT A cooler unit for cooling ingredient water or other liquids, wherein the liquid may be used in processing foods by direct contact with the foods or edible liquids may be cooled. The cooler unit includes a generally cylindrical tank of shell-andtube construction having an array of 3-inch diameter stainless steel tubes and end chambers partitioned by baffles connecting the tubes in series circuit relation, all surfaces exposed to the ingredient liquid being stainless steel. Liquid refrigerant is supplied to the interior of the shell above the tube array to discharge in droplets over the outer tubes surfaces along their whole length.

SHEET 1 [1F 4 PATENTED JAM 8 m2 IN VENTOR ATTORNEYS WILL\AM F. Morzmsflfiz. msiigr'mgi PATENTEB JMH 8 m2 SHEET 4 BF 4 IN VENTOR Q ATTORNEYS WILLJAM F. Moams, 3aw lm' wf INGREDIENT WATER CI-IILLEIR APPARATUS BACKGROUND AND OBJECTS OF THE INVENTION The present invention relates in general to ingredient water chillers, and more particularly to flooded shell-and-tube water chillers wherein ingredient water for cooling food items, such as poultry and the like, is circulated through a stainless steel circuit and refrigerant liquid is recirculated from overhead distributors downwardly over plural tubes carrying the water.

Coolers wherein refrigerant is sprayed on the outside of water carrying tubes which are within a closed shell have been previously provided. However, maintenance of adequate cooling with a minimum refrigerant charge, minimizing cost of stainless steel required for the ingredient water circuit, providing optimum strength, minimizing flooding or slugging into the refrigerant compressor, accomplishing oil return, elimination of mechanical pumps and similar considerations have been recognized problems in the design of ingredient water chillers.

An object of the present invention is the provision of an ingredient water chiller which minimizes the cost of stainless steel required for an all-stainlesssteel ingredient circuit.

Another object of the present invention is the provision of such an ingredient water chiller wherein the components are constructed in such a way as to increase strength and minimize the possibility of leaks.

A further object of the present invention is the provision of an ingredient water chiller wherein full refrigerant coverage uniformly over the tube surfaces is assured, refrigerant is distributed more uniformly over the tubes, and suctiori is applied from a location giving maximum control over liquid droplets getting into suction vapor to minimize slugging or flooding into the compressor suction and assure uniform superheat in suction gas.

Another object of the present invention is the provision of a novel ingredient water chiller design which minimizes the possibility of freezeups and if some freezing does occur, the resulting insulating effect on the evaporator surface will reduce the refrigeration load and consequently the liquid refrigerant flow to the refrigerant recirculating circuit in the evaporator until pumping action will stop, and thus the system cuts off.

Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a side elevation view of an ingredient water chiller embodying the present invention;

FIG. 2 is an end elevation thereof;

FIG. 3 is a vertical longitudinal section view taken along the line 3-3 of FIG. 2;

FIGS. 4 and 5 are vertical transverse section views showing the baffle plate patterns of the end assemblies taken along the

lines

44 and 55 of FIG, 3 respectively;

FIG. 6 is a vertical section view through the evaporator tank at one of the vertical refrigerant recirculating pipes, taken along the line 66 of FIG. 3;

FIG. 7 is a horizontal section view taken along the line 7-7 ofFIG. 3;

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, wherein like reference characters designate corresponding parts throughout the several figures, there is shown an ingredient water chiller generally indicated by the reference character 10, comprising a generally cylindrical evaporator shell or tank llll having a cylindrical wall 12 and

opposite end assemblies

13 and 14. The evaporator tank 11 is carried by vertical support plates 15 on a skid or supporting base 16. Surmounted on the tank 11 are most of the other necessary refrigeration system components, including the refrigeration motor-compressor unit 17, a water-cooled condenser 18, a combination heat exchanger and suction accumulator l9 and an electrical control panel 20. Other conventional devices may be incorporated in the refrigeration system, including such elements as a liquid line oil separator 21, a liquid line filter 22 and the like.

Within the tank are arranged a plurality of stainless steel tubes, preferably 3 inches in diameter, to carry the ingredient water, the tubes being indicated by the reference character 24 and being arranged in a plurality of horizontal rows and vertical columns along parallel horizontal axes, as indicated in FIGS. 4-6, in the preferred embodiment, with the end of each tube welded in accurately sized openings therefore in stainless steel vertical tube-supporting

plates

25, 25A whose circular peripheries are in turn welded to the cylindrical wall 12 of the evaporator tank 1 l at points spaced slightly inwardly from the ends thereof.

One of the end assemblies 13 has a warm-water inlet pipe 26 and a cool-water outlet pipe 27 fixed therein and passing therethrough to provide for the inlet and outlet of the ingredient water. A suitable arrangement of baffle plates 28 abut the vertical end plate 29 of end assembly 13 and are welded to the adjacent plate 25, and baffle plates 30 abut end plate 31 of end assembly 14 and are welded to the plate 25A, in patterns for example as illustrated in FIGS. 4 and 5, to provide communication between the ends of adjacent pairs of the tubes 24 so as to route the ingredient water in series circuit relation through the plurality of tubes 24 within the evaporator tank 11. As shown in FIGS. 4 and 5, the

baffle plates

28 and 30 are made up of horizontal baffle plates sections 28A, 30A and vertical baffle plates sections 288 and 30B, extending in planes perpendicular to the vertical planes of the

end plates

29 and 31, and are welded to the tube-supporting plates 25 in zones between the slightly protruding ends of tubes 24, as shown. The tube-supporting

plates

25, 25A and the

baffle plates

28 and 30 are all of stainless steel, and the

end plates

29 and 31 are each formed, for example, of outer mild steel plate which is inwardly lined with a stainless steel liner indicated at 29A and 31A and a stainless steel liner is provided in the inner surface of the portions of the shell which project beyond the

plates

25, 25A, so that all surfaces exposed to the ingredient water are stainless steel. The opposite ends of the cylindrical wall portion 12 of the evaporator tank 11 are provided with radially outwardly projecting circular mounting flanges, with which the circular peripheries of the

end plates

29 and 31 register and to which the end plates are bolted to secure the end assemblies on the cylindrical wall of the evaporator tank 11.

The lower center region of the cylindrical wall 12 of the evaporator tank is provided with a downwardly extending refrigerant sump 33 having a threaded coupling 33A at the lowermost part thereof and a drain line fitting 33B immediately adjacent thereto.

A U-shaped conduit section 35 of the suction conduit portion of the refrigeration system has the lower U" or bend portion 35A thereof located within the chamber defined by the refrigerant sump 33 and has a first vertical leg 36 forming the intake leg providing an open upper end 36A in the pace above the uppermost row of tubes 24 and the top of the cylindrical wall 12. A second vertical leg 37 of the conduit section 35 extends upwardly through the top of the cylindrical wall 12 and connects to the combination heat exchanger and suction accumulator 19 for withdrawal of vaporized refrigerant from the uppermost region of the evaporator tank 11 into the accumulator 19 and eventual return of the vaporized refrigerant through the suction line 19A to the compressor. An oil return orifice 35A is provided in the bottom of the U-bend 35A for the return of any oil in the conduit section 35 to the liquid in the sump 33.

The coupling 33A of the refrigerant sump 33 is connected to a T fitting and thence to oppositely directed branch pipe 38A, 383 to junction fittings 39A, 398, respectively, from which extend vertical

refrigerant recirculation pipes

40A, 408 which pass through the cylindrical wall 12 at the bottom thereof and terminate in open ends near the top of the tank 11 immediately above the bottom of a liquid distributing pan 41. Spaced slightly above the upper outlet end of the vertical

refrigerant recirculation pipes

40A and 408 on risers welded to the bottom of the liquid distribution pan 41 are deflector cones 42 having a flat top wall and depending frustoconical sidewalls to deflect the refrigerant discharging from the

pipes

40A and 408 in the directions indicated by the arrows in FIG. 3.

The liquid distribution pan 41 has a length to span the major portion of the axial length of tubes 24, as will be apparent from FIG. 3 and has a width to span the total transverse width of the array of tubes 24 and comprises, for example, integral bottom, side and end walls and inwardly extending.shallow flanges of about z-inch width formed of sheet metal. The bottom 41A has four rows of longitudinally spaced holes 43, for example, %-inch diameter holes spaced about 4 inches apart, aligned vertically with the axes of the four columns of pipes 24. The pan 41 is in turn supported on transverse rods 44, for example of A-inch mild steel, welded to the upper surface of the pan bottom 41A and which bear on and are welded to the upper edges of four angle irons 45 for example l 9% inch by l 9; inch angle irons turned 45 upright and provided with VB- inch diameter holes 45A on 1 inch centers through the bottom corner or apex of each angle. Short rod sections 46, which also may be of fir-rod, are welded to the bottom corners of the angle irons 45 and to a flat metal bar 47 for example, at Va by %-inch bar which longitudinally spans the distance between the tube-supporting

plates

25, 25A. Each of the tubes 24 are externally helically wrapped with 16 gauge galvanized wire 48 on /e-inch centers to enhance thermal transfer between the refrigerant on the exterior of the tubes 24 and the ingredient water flowing therethrough. The flat metal bars 47 sit directly against the helical wires 48 on the respective associated uppermost tubes 24. The bottom of the pan 41 is covered with screen mesh wire 41B spanning the space between the inturned flanges at the top of the side and end walls of the pan 41.

Phillips refrigeration injector-type recirculators 50 are provided in the junction fittings 39A and 398. These

fittings

39A, 39B are also connected to high pressure smaller diameter supply lines 51A, 51B having a T fitting at their center coupled to a single supply line 52 which is coupled to the helical pipe in the combination heat exchanger and accumulator 19 in turn connected to a source of warm high-pressure liquid refrigerant from the condenser by its inlet pipe 52A. A Phillips float valve 53 is coupled to the refrigerant well or sump 33, and together with the injectors 50 comprise a low pressure float and injector-type liquid recirculation system of the type marketed by H. A. Phillips & Company, 11]., and which is the subject of papers published by H. A. Phillips in the June 1945 and Dec. 1939 issues of Refrigeration Engineering.

Hot gaseous refrigerant is conveyed from the compressor 17 in the usual manner through discharge line 55 and oil separator 21 to the condenser-receiver 18, and the liquid refrigerant then courses through liquid line 52A to the helical pipe in the combination heat exchanger and suction accumulator 19 for conveyance to the supply line 52 as previously described. The suction line 19A seen in both FIGS. 2 and 3 provide for return of vapor phase low-pressure refrigerant to the compressor 17 to complete the refrigerant loop.

The refrigeration system may also include either the usual evaporator pressure regulator or the suction pressure control and a thermostate which extends into the shell to meter the temperature of the chilled water, for example at a location such as that indicated by thermostat 55 mounted in the end assembly 13 as indicated in FIG. 3, these control elements together with the Phillips float and injector type liquid recirculation system giving close control of refrigeration over a wide range. In accordance with the usual Phillips systems, a makeup line 53A extending from a T-fltting in the supply line 52 and controlled by a solenoid valve or other electrically controlled valve indicated at 53V is provided between the float valve 53 unit sensing the level of refrigerant in the sump 33 and the supply line 52 to supply additional refrigerant to the sump when the refrigerant level in the sump 33 drops below a selected level.

The above described water chiller evaporator provides a highly desirable unit of shell and tube type construction with a continuous pass all stainless steel water circuit formed of 3- inch diameter tubes for passage of the ingredient water in thermal exchange relation with the refrigerant. The evaporator shell or tank has

removable end heads

13 and 14, to facilitate full inspection and cleaning of all surfaces which come in contact with the ingredient water. The helical wires 48 on the 3-inch tubes 24, together with the distribution of the liquid refrigerant provided by the deflector cones 42, and the liquid distribution pan associated with the angleiron troughs 45 and the hole patterns provided therein, assure a highly efficient chilling of the ingredient water by the refrigerant gravity discharged through the holes in the distributing pan 41 and angle irons 45, the unit being especially designed to chill F. incoming water down to 32+ F. for use in food applications.

Freezeup hazards are minimized because of the physical arrangement of the tubes 24 since the 3-inch tubes would have to build up a one-and-a-half inch ice thickness therein before the pipes froze. The operating thermostat 55 in the above system would normally cut the system off, or the pressure in the evaporator would drop and the low-pressure control on the compressor would normally cut off the compressor before this occurred. Even if by some unpredictable set of circumstances freezing should occur, the resulting insulating effect on the evaporator surface will reduce the refrigerant load and consequently the liquid flow to the injectors until pumping action would stop. At this point all refrigerant load would disappear and the system would pump down and cut off. When the system cuts off, the pressure from the condenser equalizes through the injectors to build up pressure in the evaporator and actually warm up the evaporator surface by high-pressure, high-temperature vapor condensing on the evaporator surfaces.

The combination of the float feed together with the Phillips injectors maintains the liquid level in the evaporator sump 33 high enough to flood the injectors and low enough to be below the bottom of the main vessel, in order to minimize refrigerant charge and to assure high enough velocity of liquid refrigerant in the sump to keep oil in suspension. The gravity pan-type distribution system with the v-troughs formed by the angle irons 45 assures full refrigerant coverage uniformly over all of the surfaces of tubes 24 with minimum GPM circulation.

The fundamental structural features of the evaporator tank previously described, which in one embodiment is used with a 40-horsepower compressor may be carried forward into higher capacity units, for example using an 80 horsepower compressor or a -horsepower compressor. One need merely elongate the evaporator tank and the tubes 24 therein, and increase the refrigerant recirculating and suction conduit components. For example, for an 80-horsepower unit, the tank may have a length of about 14 feet, as compared with a 7- foot length for the 40-horsepower unit, and may have 4 vertical refrigerant recirculating pipes like the

pipes

40A, 40B of the 40-horsepower unit, with a corresponding increase in the number of deflecting cones and the Phillips injectors feeding the bottoms of the recirculating pipes, an providing two U- shaped suction return conduits sections like the section 35 of the 40 horsepower model, with the bottoms of the bends located at staggered vertical levels in the sump 33. Likewise, for a 125 horsepower unit, 6 vertical recirculating pipes like the

pipes

40A, 40B may be provided together with their associated deflector cones and injector units, and a third U- shaped suction conduit section like the section 35 may be used. In the 125-horsepower unit, the evaporator tank may have a length of 22 feet.

It will be apparent that other baffle arrangement than those illustrated may be provided, to establish parallel circuits or multiple series circuits for flow of ingredient liquid through a single shell. Also, liquid chemicals or edible liquids may be circulated through the tubes, instead of ingredient water, to effect cooling of the liquid being circulated. The deflector cones 42 may, of course, be omitted, if desired, and the suction conduit or conduits 35 may be relocated in other portions of the shell than that illustrated. The evaporator tank 11 may be remote from the other refrigeration system components, if desired, and each injector associated with the recirculation pipes may be supplied with solenoid valves in the liquid refrigerant supply line to the injectors to be cut off as desired and allow operation of the system when the compressor is in capacity reduction.

What is claimed is l. A liquid chiller unit for cooling liquids of the types including ingredient water to be supplied to a food item processing chamber to cool the food items by direct contact therewith and edible liquids to be conveyed directly through the unit, comprising a generally cylindrical elongated evaporator tank having a cylindrical outer shell, a plurality of elongated straight cylindrical tubes of about 3-inch diameter arranged in an array of vertical columns and horizontal rows within the shell with each tube extending the length of the shell, a pair of tube-supporting plates fixed in the respective opposite end portions of the shell havingapertures accommodating the end portions of the tubes and secured to the tubes to support the latter, a pair of end plates removably secured to the opposite end portions of the shell, inlet and outlet water connections passing through one of said end plates for communication of ingredient water to and from a respective pair of the tubes, means located between the end plates and adjacent tube-supporting plates defining fluid connecting passages between ends of selected pairs of tubes to connect all of the tubes in a single continuous series circuit for flow of the ingredient water therethrough, liquid-refrigerant distributing means above the uppermost tubes for gravity discharging refrigerant in droplet form downwardly on the uppermost tubes of the array substantially uniformly along the axial length thereof, refrigeration means for supplying liquid refrigerant to said refrigerant distributing means, said tank including a downwardly extending well forming a liquidrefrigerant sump depending from the bottom of said shell substantially at the longitudinal center thereof to receive the liquid refrigerant which discharges from said tubes, and means for maintaining the level of liquid refrigerant in said tank at a selected'position in said sump whereby all of said tubes are spaced above the liquid refrigerant level.

2. A liquid chiller unit as defined in claim 1, including a pair of refrigerant recirculating vertical pipes spaced toward the opposite end plates from said longitudinal center and extending from below the shell through the tube array to an open upper end for discharge of refrigerant above the array and onto the tubes, recirculation conduits connecting the sump with the lower ends of said vertical pipes, said refrigeration means including a compressor and a supply conduit system and injectors at the junction of said vertical pipes and recirculation conduits to deliver liquid refrigerant under pressure to said vertical pipes and pump liquid refrigerant from said sump therewith through the upper end of said vertical pipes for discharge onto the tubes, and a U-shaped suction conduit section including lower U-shaped bend portion submerged in the liquid refrigerant in the sump connecting an intake vertical leg rising therefrom terminating in an open upper end in the space above said tubes for intake of vapor phase refrigerant and a second vertical leg extending through the shell for external connection to a heat exchanger and suction accumulator device and compressor, the U-shaped bend portion having an orifice in the bottom thereof for selected passage of oil therethrough.

3. A liquid chiller unit as defined in claim 1, wherein said tubes, said shell, said tube-supporting plates, and the confronting surfaces of said end plates which collectively form the surfaces of the evaporator tank exposed to direct contact with ingredientwater are of stainless steel.

4. A liquid chiller unit as defined in claim 2, wherein said tubes, said shell, said tube-supporting plates, said plate segments, and the confronting surfaces of said end plates which collectively form the surfaces of the evaporator tank exposed to direct contact with the ingredient water are of stainless steel.

5. A liquid chiller unit as defined in claim 1, including a refrigerant distributing pan laterally spanning and extending over the major axial length of said tubes, said pan including a Hat bottom having plural rows of longitudinally spaced holes therein arranged substantially in the vertical planes of the axes of the tubes, and an upwardly opening V-shaped trough un derlying each of the respective rows of holes and having spaced holes in the lower apex thereof to collectively distribute the refrigerant from the pan along the axial length of the tubes.

6. A liquid chiller unit as defined in claim 2, including a refrigerant distributing pan laterally spanning and extending over the major axial length of said tubes, said pan including a flat bottom having plural rows of longitudinally spaced holes therein arranged substantially in the vertical planes of the axes of the tubes, and an upwardly opening V-shaped trough underlying each of the respective rows of holes and having spaced holes in the lower apex thereof to collectively distribute the refrigerant from the pan along the axial length of the tubes.

7. A liquid chiller unit as defined in claim 1, including a refrigerant distributing pan laterally spanning and extending over the major axial length of said tubes, said pan including a flat bottom having plural rows of longitudinally space holes therein arranged substantially in the vertical planes of the axes of the tubes, a upwardly opening V-shaped trough underlying each of the respective rows of holes and having spaced holes in the lower apex thereof to collectively distribute the refrigerant from the pan along the axial length of the tubes, and each of said tubes having a helical projection formed around the exterior thereof along its length between the tubesupporting plates to assist in distributing along the tubes liquid refrigerant discharged thereon from the holes in the troughs.

8. A liquid chiller unit as defined in claim 2, including a refrigerant distributing pan laterally spanning and extending over the major axial length of said tubes, said pan including a Hat bottom having plural rows of longitudinally spaced holes therein arranged substantially in the vertical planes of the axes of the tubes, a upwardly opening V-shaped trough underlying each of the respective rows of holes and having spaced holes in the lower apex thereof to collectively distribute the refrigerant from the pan along the axial length of the tubes, and each of said tubes having a helical wire wrapped around the exterior thereof along its length between the tube-supporting plates to assist in distributing along the tubes liquid refrigerant discharged thereon from the holes in the troughs.

Claims

1. A liquid chiller unit for cooling liquids of the types including ingredient water to be supplied to a food item processing chamber to cool the food items by direct contact therewith and edible liquids to be conveyed directly through the unit, comprising a generally cylindrical elongated evaporator tank having a cylindrical outer shell, a plurality of elongated straight cylindrical tubes of about 3-inch diameter arranged in an array of vertical columns and horizontal rows within the shell with each tube extending the length of the shell, a pair of tubesupporting plates fixed in the respective opposite end portions of the shell having apertures accommodating the end portions of the tubes and secured to the tubes to support the latter, a pair of end plates removably secured to the opposite end portions of the shell, inlet and outlet water connections passing through one of said end plates for communication of ingredient water to and from a respective pair of the tubes, means located between the end plates and adjacent tube-supporting plates defining fluid connecting passages between ends of selected pairs of tubes to connect all of the tubes in a single continuous series circuit for flow of the ingredient water therethrough, liquid-refrigerant distributing means above the uppermost tubes for gravity discharging refrigerant in droplet form downwardly on the uppermost tubes of the array substantially uniformly along the axial length thereof, refrigeration means for supplying liquid refrigerant to said refrigerant distributing means, said tank including a downwardly extending well forming a liquidrefrigerant sump depending from the bottom of said shell substantially at the longitudinal center thereof to receive the liquid refrigerant which discharges from said tubes, and means for maintaining the level of liquid refrigerant in said tank at a selected position in said sump whereby all of said tubes are spaced above the liquid refrigerant level.

3. A liquid chiller unit as defined in claim 1, wherein said tubes, said shell, said tube-supporting plates, and the confronting surfaces of said end plates which collectively form the surfaces of the evaporator tank exposed to direct contact with ingredient water are of stainless steel.

5. A liquid chiller unit as defined in claim 1, including a refrigerant distributing pan laterally spanning and extending over the major axial length of said tubes, said pan including a flat bottom having plural rows of longitudinally spaced holes therein arranged substantially in the vertical planes of the axes of the tubes, and an upwardly opening V-shaped trough underlying each of the respective rows of holes and having spaced holes in the lower apex thereof to collectively distribute the refrigerant from the pan along the axial length of the tubes.

7. A liquid chiller unit as defined in claim 1, including a refrigerant distributing pan laterally spanning and extending over the major axial length of said tubes, said pan including a flat bottom having plural rows of longitudinally space holes therein arranged substantially in the vertical planes of the axes of the tubes, a upwardly opening V-shaped trough underlying each of the respective rows of holes and having spaced holes in the lower apex thereof to collectively distribute the refrigerant from the pan along the axial length of the tubes, and each of said tubes having a helical projection formed around the exterior thereof along its length between the tube-supporting plates to assist in distributing along the tubes liquid refrigerant discharged thereon from the holes in the troughs.

8. A liquid chiller unit as defined in claim 2, including a refrigerant distributing pan laterally spanning and extending over the major axial length of said tubes, said pan including a flat bottom having plural rows of longitudinally spaced holes therein arranged substantially in the vertical planes of the axes of the tubes, a upwardly opening V-shaped trough underlying each of the respective rows of holes and having spaced holes in the lower apex thereof to collectively distribute the refrigerant from the pan along the axial length of the tubes, and each of said tubes having a helical wire wrapped around the exterior thereof along its length between the tube-supporting plates to assist in distributing along the tubes liquid refrigerant discharged thereon from the holes in the troughs.