PL99281B1

PL99281B1 - MASK AND TUBE HEAT EXCHANGER

Info

Publication number: PL99281B1
Application number: PL17691974A
Authority: PL
Priority date: 1974-12-28
Filing date: 1974-12-28
Publication date: 1978-06-30

Description

Przedmiotem wynalazku jest wymiennik ciepla plaszczowo-rurowy poziomy zwlaszcza desorber do absorpcyjnych urzadzen chlodniczych.Znane sa desorbery plaszczowo-rurowe poziome, w których ogrzewana goraca para wiazka rur jest zraszana roztworem wodno-amoniakalnym, którego temperatura jest nizsza od temperatury pary. Rury wiazki rur posiadaja uklad poziomy, praktycznie jednak wystepuje zwis, poglebiany w eksploatacji zjawiskiem dylatacji wywolanym róznica tempera¬ tur goracych rur i mniej nagrzanego plaszcza de- sorbera. Zwis ten jest przyczyna gromadzenia sie kondensatu pary w rurach, przez co znaczna czesc powierzchni rur nie bierze udzialu w procesie wy¬ miany ciepla i eksploatacyjna wydajnosc desorbera ulega obnizeniu.Istota wynalazku jest wymiennik ciepla, którego rury osadzone w dnach sitowych sa wygiete do gó¬ ry. Wygiecie to posiada najkorzystniej ksztalt lu¬ ku na calym odcinku pomiedzy dnami sitowymi z jednym punktem przegiecia w polowie dlugosci te¬ go odcinka. Wygiete rury wiazki rur sa podparte w pozycji najmniejszego wygiecia, jakie musi byc zachowane dla zagwarantowania splywu kondensa¬ tu i unikniecia jego gromadzenia sie w rurach.Podparcie rur wiazki rur stanowi co najmniej jedna sitowa plyta podporowa oparta o dolna czesc plaszcza wymiennika. Rury wiazki rur przechodza przez otwory plyty podporowej, która jest ponad¬ to przesuwna w kierunku do góry w prowadnicach.Wygiecie rur do góry wyeliminowalo zjawisko gro¬ madzenia sie kondensatu w rurach, poniewaz kon¬ densat ten splywa grawitacyjnie po pochylosciach rur. Wygiecie rur zwieksza sie w warunkach eks¬ ploatacyjnych w wyniku naprezen dylatacyjnych wywolanych róznica temperatur goracych rur i chlodniejszego plaszcza wymiennika. Punkty prze¬ giecia krzywizny rur przemieszczaja sie wówczas wraz z plyta podporowa do góry, dzieki czemu wa¬ runki splywu kondensatu z rur ulegaja dalszej po¬ prawie.Przedmiot wynalazku pokazany jest w przykla¬ dzie wykonania na rysunkach, na których fig. 1 przedstawia desorber plaszczowo-rurowy poziomy w przekroju osiowym podluznym, zas fig 2 przed¬ stawia ten sam desorber w przekroju poprzecznym wzdluz osi A-A na fig. 1.W dnach sitowych 1 i 2 polaczonych z plaszczem 3 desorbera osadzone sa rury 4 wygiete w luk w kierunku do góry. Kazda rura 4 wiazki rur jest wygieta w punkcie przegiecia o wielkosc równa strzalce f, okreslajacej wielkosc wygiecia minimal¬ nego. W tym polozeniu rury 4 sa podparte sitowa plyta podporowa 5, oparta o dolna czesc plaszcza 3 oraz przesuwna w prowadnicach 6 w kierunku do góry. Plyta podporowa 5 jest usytuowana poprze¬ cznie do rur 4 w srodku dlugosci pomiedzy dnami sitowymi 1 i 2 w plaszczyznie utworzonej przez punkty przegiecia poszczególnych rur 4. Rury 4 przechodza przez otwory w plycie podporowej 5. 9928199281 4 czesc plaszcza 3. Powrót plyty podporowej 5 do polozenia oparcia o dolna czesc plaszcza 3 moze nastapic po zaniknieciu róznicy temperatur pomie¬ dzy plaszczem 3, a rurami 4, na przyklad po od¬ cieciu doplywu goracej pary i roztworu amoniaku do desorbera. PLThe subject of the invention is a horizontal shell-and-tube heat exchanger, especially a desorber for cooling absorption devices. Horizontal shell-and-tube desorbers are known, in which the heated hot steam of a bundle of tubes is sprayed with a water-ammonia solution whose temperature is lower than the temperature of the steam. The pipes of the pipe bundle have a horizontal arrangement, but in practice there is an overhang, deepened in operation by the dilatation phenomenon caused by the difference in temperature of hot pipes and a less heated de-sorber jacket. This overhang is the reason for the accumulation of steam condensate in the pipes, so that a significant part of the pipe surface is not involved in the heat exchange process and the operational efficiency of the desorber is reduced. The essence of the invention is a heat exchanger, the pipes of which are bent upwards in the tube sheets. ry. This bend preferably has the shape of an arc over the entire length between the tube sheets with one inflection point halfway along the length. The bent pipes of the pipe bundle are supported in the position of the smallest bend that must be maintained to guarantee the run-off of condensate and to avoid its accumulation in the pipes. The pipe bundle pipe is supported by at least one screen support plate resting on the bottom of the exchanger shell. The pipes of the pipe bundle pass through the openings of the support plate, which is moreover slidable upwards in the guides. The upward fit of the pipes has eliminated the phenomenon of condensation build-up in the pipes, since this condensate flows by gravity on the slopes of the pipes. The bending of the pipes is increased under operating conditions as a result of the expansion stresses caused by the temperature difference of the hot pipes and the cooler exchanger shell. The bending points of the curvature of the pipes then move with the support plate upwards, so that the conditions for drainage of the condensate from the pipes are further improved. The subject of the invention is shown in the embodiment example in the drawings, in which Fig. 1 shows the desorber. the tubular horizontal in the axial longitudinal section, while Fig. 2 shows the same desorber in cross-section along the axis AA in Fig. 1. In the tube sheets 1 and 2 connected to the mantle 3 of the desorber, pipes 4 bent in a gap towards mountains. Each tube 4 of the tube bundle is bent at the inflection point by a size equal to the arrow f, which determines the amount of the minimum bend. In this position, the tubes 4 are supported by a supporting tube 5, which rests against the lower part of the mantle 3 and is slidable in the guides 6 upwards. The support plate 5 is located crosswise to the pipes 4 in the middle of the length between the tube sheets 1 and 2 in a plane formed by the bending points of the individual pipes 4. The pipes 4 pass through the openings in the supporting plate 5. 9928199281 4 shell part 3. Support plate 5 return to rest against the lower part of the mantle 3 may occur after the temperature difference between the mantle 3 and the pipes 4 has disappeared, for example after cutting off the flow of hot steam and ammonia solution to the desorber. PL

Claims

Claim 1. Horizontal shell-tube heat exchanger with two tube sheets, especially a desorber for cooling absorption devices, characterized by the fact that it has tubes (4) of tube bundles embedded in tube tubes (1, 2) bent upwards .

2. Heat exchanger according to ordinance. The pipe bundle according to claim 1, characterized in that the pipes (4) are bent in the form of an arc over the entire length between the tube sheets (1,2) and have one inflection point, most preferably half the length of this section.

3. Heat exchanger according to claim 1 allbo 2, characterized in that the bent pipes (4) of the pipe bundles are supported in the position of the smallest bend (f). 4. Heat exchanger according to claim 3. The pipe bundle according to claim 3, characterized in that the pipe bundle (4) is supported by at least one tube supporting plate (5) situated transversely to the pipes (4), resting against the lower part of the exchanger shell (3), through which the pipes (4) pass through the openings. tube bundles, the support plate (5) being slid upwards in guides (6) attached to the shell (3) of the heat exchanger. Ffg.2 Price PLN 45 GWP Druk, Zaro. 1688-78-105 3 These openings are shifted upwards in relation to the identically spaced openings in the sieve bottoms 1 and 2 with an arrow of minimum pipe bend f

4. The operation of the desorber is as follows. Hot steam is supplied to the interior of the pipes 4 of the pipe bundle, and from the side of the inter-pipe space, the walls of these pipes 4 are washed with an aqueous solution of ammonia at a temperature lower than the temperature of the steam. Through the walls of the tubes 4, a heat exchange takes place between the steam and the ammonia solution, as a result of which the steam condenses. The condensed steam flows by gravity along the arched slopes of the pipes 4 and, being unable to accumulate in the pipes 4, does not cause the exclusion of a part of the surface of the pipes 4 from the heat exchange process. The temperature of the mantle 3 of the heat exchanger is kept between the temperature of the ammonia-water solution and the ambient temperature of the exchanger and is lower than the temperature of the tubes 4 of the tube bundle. As a result of this temperature difference, the expansion stresses 20 in the jacket 3 and the pipes 4 cause an increase in the curvature of the pipes 4, and thus the bending points of the pipes 4 shift upwards with the support plate 5, which is movable in this direction in guides 6 attached to the shell 3 of the exchanger. Increasing the bend of the pipes 4 results in better conditions for the condensate drainage. The support plate 5, when enlarged as a result of expansion stresses, the bends of the pipes 4 do not rest against the lower 3 ° PL