Process for the production of tubular heat exchangers with tubes grouped together in nests
Document Number
GB Patent 606933
Publication Date
1948-08-23
Link
Inventors
not available
Abstract
Abstract of
GB606933
606,933. Making heat-exchangers. AKT.- GES. FUR TECHNISCHE STUDIEN. Jan. 22, 1946, No. 2099. Convention date, Jan. 30, 1945. [Classes 83 (ii) and 83 (iv)] Uniting by fusion.-In making tubular heatexchangers with tubes grouped together in nests and firmly connected at their ends to end walls, one end of a nest of tubes 4 is inserted loosely into the single opening of a frame 1 and the tubes are then welded at their ends to each other and to the framing into a block. The frame is provided with a groove 2 separating the welds from the main mass of the frame so as to facilitate welding. The tubes, after insertion into the frame may be widened quadrangularly or hexagonally at their ends by a hammer or pieces of wire 7 may be inserted between the parts and also welded to the ends of circular tubes and to the frame. A number of frames 5 and tube nest ends welded up into blocks are finally welded to the widened-out end of a common funnel-shaped member 8 which acts as a distributor or feeder, the narrow end being fixed in an end plate of the heatexchanger. The frame may be cut off from a square steel tube. Distance pieces may be provided between the tubes at the required distance from the frames.
Applicant: SCHMITZ & BRILL GMBH & CO KG (DE); BAYERISCHE MOTOREN WERKE AG (DE)
EC:B23K1/00S; B23K26/20
IPC: B23K26/00; B23K1/00; B23K1/18(+12)
Publication info: GB2308822 - 1997-07-09
2
Pipe joint and seal therefor
Inventor: EMMONS KURRY BRIAN (US); ZHANG JANE (US); (+2)
Applicant: METEX CORP (US)
EC:F01N7/18B1; F16L27/053; (+1)
IPC: F01N7/08; F01N7/18; F16L23/00(+7)
Publication info: US5683119 - 1997-11-04
3
Heat exchanger
Inventor: HAIGHT HOWARD N
Applicant: BRAUN & CO C F
EC:F28D7/06; F28F9/02A
IPC: F28D7/06; F28F9/02;F28D7/00(+1)
Publication info: US2919906 - 1960-01-05
Claims
claim is:-
1. Process for the production of tubular heat exchangers with tubes grouped together in nests, which are to be firmly connected at their ends to end walls, characterised by the fact that the tubes are inserted at each end of the nest loosely into the single opening of a frame and then welded at their ends to each other and to the frame into a block.
2. Process according to claim 1, characterised by the fact that the opening in the frame is of such dimensions that the tubes of the nest loosely inserted therein bear against each other and that the marginal tubes bear also against the inside of the frame.
3. Process according to claims 1 and 2, characterised by the fact that after the tubes have been inserted in the frame their ends are widened out quadrangularly and afterwards welded up in the 35 form of a honeycomb.
4. Process according to claims 1 and 2, characterised by the fact that after the tubes have been inserted in the frame their ends are widened out hexagonally 40 and afterwards welded up in the form of a honeycomb.
5. Process according to claim 1, characterised by the fact that the spaces left between the several tubes and those left 45 between said tubes and the inside of the frame are each filled up with a piece of welding wire and this latter then welded to the ends of the tubes and to the frame.
6. Process according to claim 1, characterised by the fact that frames cut oft from square steel tubes are used.
7. Process according to claim 1, characterised by the fact that a groove is formed in the frame encircling the opening thereof, so as to facilitate the welding of the marginal tubes of the nest to the frame.
Dated this 22nd day of January. 1946.
For the Applicants, LLOYD WISE & CO., 10, New Court, Lincoln's Inn, London, W.C.2, Chartered Patent Agents.
Leatnington Spa: Printed for His Majesty's Stationery Office, by the Courier Press.-1948.
Published at The Patent Office, 25, Southampton Buildings, London, W.C.2, from which copies, price Is. Od. each (inland) is. Id. (abroad) may be obtained.
Description
PATENT SPECIFICATION
M M D Convention Date (Switzerland): Jan. 30, 1945.
Application Date (in United Kingdom): Jan. 22, 1946.
Complete Specification Accepted: Aug. 23, 1948.
606,933 No. 2099/46.
Index at acceptance -. -Classes 83(ii), A 158: and 83(iv), T6.
COMPLElTE SPECIFICATION
Process for the Production of Tubular Heat Exchangers with Tubes Grouped Together in Nests We, AlSTIBNGISELLSCHAFT FUR TECHISOH1 'STIDIEN, of 319 Hardstrasse, Zurich, Switzerland, a body corporate organised under the laws of Switzerland, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:-
1t This invention relates to a process for the production of tubular heat exchangers 'with tubes grouped together in nests.
In heat exchangers of this kind a large number of tubes (as many as 40,000 and more) which, in proportion to their diameter, (6 mm. for example), are thin (0.7 mm.) and long (14 m.) have sometimes to be connected at the ends by connectors, so-called tube plates. In such case a difference of pressure of many atmospheres (20 atmospheres for example) may exist between the pressures prevailing inside the tubes and on the outsides of them and furthermore, the temperatures of the heat exchanging media may amount to several hundred degrees. It is therefore imperative that the connections between the tube plates and the ends of the tubes keep absolutely tight and that the construction is reliable in use, as subsequent repairs to single connecting points or tubes are practically impossible to carry out.
Heat exchangers with tubes of dimensions such as herein mentioned are used in thermal power plants for example in which a gaseous working medium, preferably air, continuously describes a circuit under a pressure greater than atmospheric, and wherein a part of such working medium, heated by a supply of heat derived from an external source is allowed to expand while giving up power and is afterwards re-compressed, the expanded part of the current of working medium giving up heat in a heat exchanger to that part of the current of workino medium which has been re-compressed but not yet heated by heat front an 50 external source.
The drilling of the holes for the large number of tubes in the plate like connectors which are usually comparatively thick, and the tfiting of the long and 65 thin tubes into the holes in the plates (threading in) and also the fixing of the ends of the tubes tightly into the said plates constitute working operations which take up much time and are expensive. For this reason it is already known to fix the tubes in nests to the widened or flared end of distributors or headers and to fix the narrower ends of these headers, of which there is a considerably 65 smaller number, in their turn in the coordinated plates of the heat exchanger.
The attachment of the various tubes to the distributors or headers and the fitting of these latter into the plate like connectors is however still an operation which takes up mmliob time and is therefore expensive.
In connection with coolers having small tubes of light metal in which 75 neither high pressures nor high temperatures occur, it has been found possible to dispense with the special end plates for connecting the tubes together by expanding the said tubes at their ends by means 80 of a mandrel and uniting them into a block by brazing them to one another. To enable them to be brazed however the tubes must be arranged vertically, which, in the case of tubes 14 m. long for 85 example, necessitates the construction of a special frame for the brazing chamber or else the provision of a deep pit.
Furthermore ample space accommodation is also necessary. If the brazing has to 90 be carried out in an atmosphere of hydrogen, the brazing chamber must also be very carefully sealed, firstly owing to the danger of the formation of electrolytic ( 07A ga;to aid secon(dlv because even if only smnall quantities of oxygen are present at the point which is being brazed brazing will not take place at all.
The above mentioned disadvantages which have to be put up with when brazing. is employed can be avoided if -the small tubes are welded into the end walls.
Certain difficulties are however connected with this method also. Thus experiments have shown that butt welding of the tubes to hollow projections on a previously drilled plate results in inequalities due to welding waste so that the various tubes in' a nest become of different lengths, some being stretched tig'htlv while others sag--. The various welding points in the interior of the tubes have also to be trimmed, and as the space between the tubes may amount to only 2.5 to 3 mill. welding tools of a complicated form are also rendered necessary.
The autogenous welding olf tubes inserted in a drilled tube plate is likewise expensive, and furthermore in such a case the pitch of the tubes, if the desired cross sections are to be adhered to and sufficient space shall be available for the grooves to be milled into the plate for the welding. must not fall below a certain Ilnargin.
In order also to be able to do without tube plates which require to be drilled with a large number of holes in the case of tubular heat exchangers with long, thin tubes of small diameter, and to be able to provi(le as small tube pitches as possible in the tube field the tubes according to the present invention are introd(lnced at the end of each nest loosely into the single opening of a frame and then welded at their ends to each other and to the frame into a block. This method of working can be carried out under workshop conditions easily, satisfactorily and cheaply. When this method is employed the necessarv thickness of the welding bead to be applied can be continuously supervised.
Various constructional forms of the tube nests produced according to the invention are shown by way of example in the accompanying drawing in which:
Fig. 1 is a longitudinal section on the line I-I of Fig. 2 through part of a tube nest.
Fig. 2 shows this tube nest in plan. the welded beads being omitted for the sake of clearness.
Fig. 3 show.s in the left hand half a section on the line III-III of Fig. 4 and in the right hand half the elevation of a tube nest block which is built up of four nests rigidly welded to a coinlliol.
flnnel-shapedi member and Fig. 4 shows in the lower part of the left hand half a plan view of parts which are situated below the line II-II in Fig.
3 (the welded seams being omitted) and in the top part of this left half a section 70 on the line v-V of Fig.:3, and onl the right hand half a plan view of a part of tile tube nest block.
In Figs. 1 and 2 of the drawing, 1 denotes it rectangular frame, which has 75 a single rectangular opening:3 in it. At a certain distance front the opening:3 cgrooves 2 are milled in the frame 1 encircling the opening:3. so that a rim is formed. Into the opening:3 are loosely 8() inserted the ends of circular tubes 4 of a tube nest. Said tubes 4 after they have been inserted in the opening:3 of the frame 1, are widened quadrangularlv at their ends in the manner shown in Fig. 2 85 bv a light blow with a hammer. The opening 3 in the frame 1 is of such dimensions that the tubes 4 of the nest which are loosely inserted therein bear against each other and the marginal 90 tubes of this nest in addition bear against the inside of the frame 1. The tubes are finally welded to each other at their ends in the shape of a honeycomb and also to the frame 1 into a block. The grooves 2 95 provide for the necessary separation between the welded beads and the main mass of the frame 1, that is to say they facilitate the welding of the marginal tubes of the nest to the frame. 100 Several blocks produced in the manner described, and in which conse(fuently the ends of the tubes of a tube nest are held firmly and tightly in a frame, may also le welded in eaeh case to an end wall. 105 Figs. 3 and 4 show a construction in which four tube nest blocks are grouped together. Each tube nest has a frame,r) allotted to it. The ends of the tubes (i of each nest are again welded to each 11,( other at the ends and to the associated frame 5 also. In this construction the ends of the tubes are not widened out prior to welding, but the intermediate spaces which are left between the tubes 115 6 in the frames 5 and between them and the inside of the frame are filled up with pieces of welding wire 7. These pieces of wire i are also welded to the ends of the tubes 6 and to the frame 5. The frames 120 and tube nest ends welded up into blocks are finally welded to the widened out end of a cominion, funnel-shaped member 8.
whichl, if need be, can act as a distributor or header. The narrower end of 125 this member 8 is fixed in well known wav in an end plate (not shown) of the lbea<t exchanger.
After they have been inserted into the framie thie en(ls of the tubes mavy be also 130 (i(jj;Jt:s widened out hexagonally and afterwards welded together in the form of a honeycomb. The frames may be cut off from square steel tubes for example.
At a certain distance from the frames intermediate spaces of any desired size may also be maintained between the tubes of the nest by distance pieces, guide plates and the like.
Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we
