US 3785170 A
An absorption cooling unit including a heat exchanger consisting of a plurality of telescoping tubes that comprises an inner tube which is adapted to feed a rich solution therethrough and that extends straight. An outer tube has an inner wall and the latter is engaged at least partly by the inner tubes. The inner tube has over its straight length a uniformly extending flat shape, to include flat walls. The outer tube has ribs on opposite sides which ribs are spaced apart from each other. The ribs extend up to the flat walls of the inner tube, and on one side in between relative to the ribs on the opposite side.
Description (OCR text may contain errors)
Umterl States Patent 1191 3,785,170 Beranek Jan. 15, 1974 ABSORPTION TYPE COOLING UNIT 2,259,433 10/1941 Kim) 138/113 x 2,634,108 4/1953 Rohman  Beranek Donberg' 2,691,874 10 1954 Martin 62/489 Germany A g rm Varwerk & 4 Primary Examiner-William F. ODea l k 'tl K Assistant Examiner-Peter D. Ferguson W pp r m G y Att0rney-Ernest G. Montague  Filed: July 7, 1972  Appl. No.: 269,745  ABSTRACT An absorption cooling unit including a heat exchanger  Foreign Application P i rit D t consisting of a plurality of telescoping tubes that com- July 9 1972 Germany P 21 34 278.9 prises inner tube which is adapted to feed a rich lution therethrough and that extends straight. An 52 US. Cl 62/489, 62/490 138/114 Outer tube has an inner Wall and the latter is engaged 165/154: at least partly by the inner tubes. The inner tube has 51 1m. 01. F25b 15/10 its Straight length extending flat  Field of Search 62/490 491 492 Shape, include flat Walls- The Outer tube has ribs 62/493 489 138/113 3 opposite sides which ribs are spaced apart from each other. The ribs extend up to the flat walls of the inner  References Cited tube, and on one side in between relative to the ribs UNITED STATES PATENTS the (mom l 787,904 1/1931 Heyward 165/154 1 Claim, 4 Drawing Figures PAIENIED JAN 1 51974 SHE-U1 or 2 ABSORPTION TYPE COOLING UNIT The present invention relates to an absorption type cooling unit with heat exchangers consisting of telescoping tubes, in which the straight extending inner tube, feeding the rich solution, due to deviation from the throughout round cross-sectional shape engages at some points the inner wall of an outer tube.
It is known to improve in water pipes for vessels, feedheaters, condensers or the like, the heat exchange capacity of such pipes by variation of the direction and the passage cross-section of the liquid.
A generic liquid-heat exchanger is formed as a rule of two concentrically disposed tubes. They are bent to a screw coil. This coil must be bent very carefully, i.e. without essential cross-sectional variations, and placed with a sufficient pitch. This is necessary, because dissolved carrier gas is present in the rich solution, which carrier gas gets free by the raised solubility during the passage through the changer and can obstruct the flow of the rich solution. Proposals have been made already, to place the liquid-heat-exchanger in a straight tube. In view of the required heat exchange faces, the tube dimensions get then, however, large to a great extent. This leads to the fact, that the liquid volume present in the exchanger is very large and in addition local noncontrollable circulations are experienced, which worsen the heat exchange.
It is one object of the present invention to provide an absorption type cooling unit which is straight, which avoids the above stated drawbacks'and which has with realization of a favorable hydraulic diameter large heat exchange faces with a small liquid volume. A corresponding structure is supposed to be simple concerning its production and is supposed to make possible an easy placing in the unit.
It is another object of the present invention to pro vide an absorption type cooling unit, wherein an inner tube is pressed along its straight portion into a uniformly passing flat shape and an outer tube has embossed ribs pressed-in on opposite sides and arranged spaced apart from each other, which embossed ribs extend up to the flat walls of the inner tube and are arranged such, that the embossed ribs of one side are placed spaced relative to the embossed ribs of the opposite side.
By this arrangement, a liquid heat exchanger for absorption-cooling-units of high efficiency is created. The production is simple and its mounting can easily be performed. The exchanger can assume substantiallly a straight arrangement. Its inner tube has a uniformly passing flat shape. The outer tube, equipped with embossed beads, which form corresponding embossed ribs, which extend to the flatly pressed wall sections, fixes the inner tube. A favorable hydraulic diameter is realized. Due to the fact, that the embossed ribs of one side sit in between relative to the embossed ribs of the opposite side, the poor solution flows in a kind of a wave like with obtaining amplitude. The returning poor solution is forced to flow in a cross stream to the inner tube. By the flat pressing of the inner tube, the inner volume of this tube is reduced. This is accomplished with the realization of a large heat-exchange-face. By sufficient cross-sections and a relatively short length, the danger of blocking by hydrogen bubbles does 'not exist, nevertheless. For this reason the pitch angle can be held also small. The realization of a small crosssection in the inner tube avoids a local circulation impairing the efficiency.
With these and other objects in view, which will become apparent in the following detailed description, the present invention, which is shown by example only, will be clearly understood in connection with the accompanying drawings, in which:
FIG. 1 is an elevation of the absorption unit designed in accordance with the present invention and disclosing the liquid-heat-exchanger;
FIG. 2 is an elevation of the liquid-heat-exchanger indicating the outer tube in section for the purpose of a better demonstration;
FIG. 3 is a section along the lines IIIIII of FIG. 2; and
FIG. 4 is a section along the lines IV-IV of FIG. 2.
Referring now to the drawings and in particular to FIG. 1, the absorption cooling unit comprises a carrier 1 consisting of two cap portions l and II which are welded together along the cross-plane x-x.
An outer tube 5 emerges from the cap portion 1 through a bottom opening 3 of the latter. The outer tube 5 is welded to the cap portion 1 at 6 and enters at a coaxially opposite point as a gas heat exchanger-inner tube 5 into a gas heat exchanger-outer tube 7 which emerges from the other cap portion. II. The gas-heat exchanger-outer tube 7 is secured by means of a welding seam 8 to the carrier 1 or the cap portion II, respectively. For this purpose, a passage opening 4 is provided in the latter.
The heat exchanger-outer tube 7 and the gas heat exchanger inner tube 5 are adjusted relative to each other concerning their cross-sections, such, that a sufficiently large annular chamber remains between the inner wall of the gas heat exchanger-outer tube 7 and the outer wall of the gas heat exchanger-inner tube 5. For the improvement of the heat exchange, deformations 5"" can be provided on the gas heat exchanger. The upper part of the gas heat exchanger forms the evaporator of the cooling unit.
The outer tube 5, which emerges from the cap portion I and which passes through the carrier 1, extends throughout the liquid heat interaction path 9, the boiler path 9', the rectification path 10, the boiler ascending tube path 11 and the dephlegmator path 12 up to the condenser 13. The outer tube 5 surrounds thereby the inner tube 14 separately terminating into the carrier 1 and extending to the boiler ascending tube path 11.
This inner tube 14 and the outer tube 5 are chosen as to their diameters, also such, that between the inner wall of the outer tube 5 and the outer wall of the inner tube 14 likewise the required annular gap is assured.
The inner tube 14 is pressed flat within the range of its small angular rise (compare FIG. 1, liquid heat interaction path 9) with obtaining of .a reduction of the cross-section. This innertube l4 feeds the rich solution to the carrier 1.
The flattened wall sections of the inner tube 14 are identified by the sections 14'. They extend horizontally and in particular symmetrically to the center axis Y-Y (FIG. 4). The outer tube 5 extending concentrically about the inner tube 14 has beads 30 aligned cross-wise to the tube. The beads 30 are obtained by embossing, so that ribs 31 are obtained which correspond with the shape of the beads and extend into the inside of the outer tube 5. The ribs 31 approach engagingly the flat wall sections 14' of the inner tube 14. The ribs 31 are of equal height and are arranged such, that the ribs 31 of one side sit in between relative to the ribs 31 of the opposite side. The tube wall thus projecting reciprocally in form of the ribs 31 leads to the result, that the poor solution flows in a cross-stream to the inner tube. With a small liquid volume ocurring also here, a large heat exchange face is realized. There the pitch angle of the liquid heat exchanger can also be kept low. No local circulations occur, which worsen the efficiency. Also the engagement points between the end faces of the ribs and the flattened wall sections favor the heat exchange. During the embossing of the ribs, the adjacent tube wall sections 32 of the outer tube bulge beyond the normal tube cross-section. (FIG. 4). The end of the inner tube 14, extending after the finished assembly into the inner space 1' of the carrier 1, is there radially curved outwardly. The curved section is shown in FIG. 1. The end face of the tube 14 has an end-sided curvature corresponding with the wall configuration and is connected by means of a welding connection on the bore wall of equal configuration of the bore 17, which provides the flow communication of the inner tube 14 with the inner space 1 of the carrier 1. Prior to coordination of the inner tube 14 to the outer tube 5, the latter is connected with the pump tube 18 of the unit. The pump tube 18 extends, again with the provision of an annular split inside of the inner tube 14. It reaches beyond the rectification insert 20 disposed therein and in a telescoping state up to in front of the dephlegmator path 12. The latter has a typical formation by sectional, angularly set-off flattening of the particular section of the passing-through outer tube 5. The corresponding grooves created thereby are identified by the grooves 12'.
The condenser 13 following this section is equipped with ribs 22. Within the range of the condenser 13, the outer tube is equipped with a displacing tube 13 which is centrally inserted, closed on both sides and smaller in diameter, in order to increase in this range the vapor speed and thereby to improve the heat exchange as well as to prevent the innert gas stream. Following the condenser 13 the passing through outer tube 5 (section 5") falls. It transforms into the ammonia tube 23 of smaller cross-section. The tubes are connected together by a welding 24. The ammonia tube 23 extends then, after curving in opposite direction parallel to the gas heat exchanger-outer-tube 7, which is connected at one end, as stated above, with the cap portion II of the carrier 1 and is closed at the other end. The ammonia tube 23 enters prior to the closed end 7' into the outer tube 7 of the gas heat exchanger. The end section has at a corresponding connection point a passage opening, which connects the ammonia tube 23 with the annular chamber between the inner wall of the outer tube 7 of the gas heat exchanger and the outer wall 5 extending therein and operating as an inner tube 5 of the gas heat exchanger.
The upper part of the outer tube 7 of the gas heat exchanger constitutes the evaporator of the cooling unit. Following merely still a connection tube 25 between the other end section 5" of the outer tube and the outer tube 7 of the gas heat exchanger is to be provided. Furthermore still a serpentine 26 is provided. The latter emerges in the vicinity of the bottom 2 of the cap portion II and is connected with its other end with the inner tube 5 of the gas heat exchanger while passing through the outer tube 7 of the gas heat exchanger, which inner tube 5' passes also in the bottom 2 of the same cap portion II of the carrier 1. The absorption cooling unit has finally a cartridge heater 27. The latter is disposed within the range of the boiler 9' below the restriction insert 20.
While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting one.
1. In an absorption cooling unit having a generator, a condenser, an evaporator, an absorber, and a collector operatively connected by conduit means and including a heat exchanger operatively connected between said collector and said generator consisting of a plurality of telescoping tubes, comprising an inner tube adapted to feed a rich solution therethrough and extending straight,
an outer tube having an inner wall and said inner wall being engaged at least partly by said inner tube, said inner tube having over its straight length a uniformly extending flat shape, to include flat walls, said outer tube having on opposite sides, ribs spaced apart from each other,
said ribs extending up to said flat walls of said inner tube, and
said ribs on one side being off-set relative to said ribs on the opposite side.