GB1572777A

GB1572777A - Tube bundle heat exchanger

Info

Publication number: GB1572777A
Application number: GB742978A
Authority: GB
Original assignee: Carl Zeiss AG
Current assignee: Carl Zeiss AG
Priority date: 1977-03-02
Filing date: 1978-02-24
Publication date: 1980-08-06
Also published as: FR2382668A1; DE2709027B2; DE2709027C3; DE2709027A1; FR2382668B1

Description

(54) TUBE BUNDLE HEAT EXCHANGER (71) We, CARL-ZEISS-STIFTUNG trading as JENAER GLASWERK SCHOTT & GEN., a Foundation organised and existing under the Federal Laws of Germany, of Hattenbergstrasse 10, 6500 Mainz, West Germany, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to tube bundle heat exchangers having tube bundles of glass or similar material with two tube plates on either side.The tube bundle heat exchanger according to the invention is designed in such a manner that, in the event of leakages, both from the jacket- and the hood-side (productand service- side) between tubes in the tube bundle and the tube plates, none of these leakages may reach the space reserved for the other medium in the tube plate, but enters the space between the two tubeplates.

The principle of the double plate on either side is already well known and is often used in the design of metal tube bundle heatexchangers. In this case the tubes are rolled into the tube plate, then welded, soldered or sealed by means of individual glands.

Tube bundle heat exchangers have been known for some time, in which the tubes consist of glass or a similar material, the face-places being made of plastic and the tubes being sealed in position with a sealing compound (see German Utility Model No.

7404616). In the event of leakages through these tube seals, the leaking medium reaches the medium on the other side of the faceplate. This mixing of media is particularly undesirable where deterioration or damage to the media or a chemical or physical reaction between the media may occur, or when dangerous toxic-inflamable-, healthinjurious- materials may reach the wrong ducting circuit. This leakage of the medium into the space reserved for the other medium is prevented with complete safety by means of double end plates.

The designs manufactured from metallic materials cannot be used in the case where brittle materials are used for the heat exchanger tubes since, in spite of accurate manufacture of the tube plates and alignment, there are still slight axial deviations at the ends of individual tubes which, on fitting and sealing with radial sealing components lead to stressing or even eventual fracture.

According to the present invention, there is provided a tube bundle heat exchange comprising a jacket, end caps for the jacket, a tube bundle mounted within the jacket, a double tube plate assembly disposed at each end of the tube bundle, and seals between the individual tubes and each assembly, wherein the seal between each tube and the tube plate which faces the interior of the jacket acts radially on the tube whereas the seal between each tube and the tube plate facing the respective end cap acts axially on the tube.

In the accompanying drawings: Fig. 1 is a side elevation of one embodiment of tube bundle heat exchanger according to the present invention, Fig. 2 is an axial section through part of the heat exchanger of Fig. 1, and Fig. 3 is a view similar to Fig. 2 of an alternative construction.

Referring now to Figs. 1 and 2, the tube bundle heat exchanger comprises a composite jacket 1 provided with inlet and outlet spigots 2 for passage of one medium through the jacket 1. The heat exchanger further comprises two end caps 3 provided with spigots 4. A tube bundle consisting of a multiplicity of individual tubes 12 is disposed in the jacket 1 and sealed therein by means of two double tube plates 5 so that the interiors of the tubes 12 communicate with the spaces within the end caps 3, the tubes 12 being sealed with respect to the tube plates 5. Each tube plate 5 comprises a plate 6 facing the jacket, a plate 7 facing the respective end cap 3 and a spacer 8 fixed to the plate 7 in this embodiment. In an alternative embodiment, the spacer 8 may be clamped removably between the two plates 6 and 7.The double plate 5 is clamped in a manner known per se between the jacket 1 and the respective end cap 3 by means of a flange connection including clamping bolts 9 and is sealed by seals 10 and 11. The tubes 12 of the tube bundle are radially sealed in the tube plate 6 by means of glands 13 and packing cord 17. Flexible sealing rings 14 are mounted on the ends of the tubes 12. In the embodiment illustrated here, the sealing rings 14 each have an annular recess therein to receive the end of the respective tube 12. Internally screw threaded holes are provided in the plate 7 in alignment with the tube receiving holes in the plate 6.

Externally screw threaded bushes 15 are engaged in the screw threaded holes in the tube 7 and are sealed therewith by means of permanently flexible sealing material. The end face 16 of each threaded bush 15 which faces the plate 6 abuts against the respective sealing ring 14 to compress the latter and thereby produce the necessary axial sealing force.

The following advantages are achieved with the above described design: The end or frontal sealing of the tubes relative to the plate 7 produces no radially directed forces at the ends and thus avoids bending stresses which would otherwise lead to fractures.

Normal commercial tubing 12 having diameter tolerances in accordance with standard specifications may be used for the tube bundles since diameter variations have no effect upon the pressure tightness as a result of the use of the packing cord seal 17 and seal 14.

The longitudinal tolerances for the tubes 12 are compensated for by the adjustability of the bushes 15 in the axial direction relative to the tube 12.

Any unavoidable variations in the alignment between the respective holes through the plate 6 and 7 is compensated for because of the sealing of the ring 14 with the end face 16 of the respective bush 15 so that slight mis-alignment between the axis of the bush 15 and the axis of the sealing ring 14 will not destroy the seal between these two parts.

Referring now to Fig. 3, the double tube arrangement illustrated therein has a plate 18 which replaces the plate 7 previously described. The plate 18 is pierced with holes and fitted with sealing washers 19 sunk in recesses around the holes. The end faces of the respective tubes 12 engage against the sealing washers 19. In this embodiment, however, it will be appreciated that the tubes 12 must be accurately cut to length.

In both of the above-described embodi ments, both the tubes 12 and the jacket 1 are formed of glass.

It is also within the scope of the present invention to provide the following constructions: 1. A heat exchange which is provided at both ends with the plate 7 with threaded bushes 15, 2. A heat exchanger provided at one end with the plate 7 and threaded bushes 15 and at the other end with the plate 18 with inset sealing rings 19 and 3. A heat exchange provided at both ends with plates 18 within said sealing rings 19.

WHAT WE CLAIM IS: 1. A tube bundle heat exchanger comprising a jacket, end caps for the jacket, a tube bundle mounted within the jacket, a double tube plate assembly disposed at each end of the tube bundle, and seals between the individual tubes and each assembly, wherein the seal between each tube and the tube plate which faces the interior of the jacket acts radially on the tube whereas the seal between each tube and the tube plate facing the respective end cap acts axially on the tube.

2. A heat exchanger as claimed in claim 1, wherein the axial tube seal for at least one of the assemblies is effected through the intermediary of a respective threaded bush which is axially displaceable relative to the respective tube.

3. A heat exchanger as claimed in claim 2, wherein each threaded bush has a smooth end face so that sealing can be effected in the event where there is an axial mis-alignment between the tube and the respective threaded bush.

4. A heat exchanger as claimed in claim 2 or 3, wherein both of the plates facing the respective end caps are provided with the threaded bushes.

5. A heat exchanger as claimed in claim 2 or 3, wherein only the tube plate which faces one of the end caps is provided with the threaded bushes and the tube plate facing the other end cap is provided with inset sealing rings which act axially against the respective ends of the tubes.

6. A heat exchanger as claimed in claim 1, wherein both of the tube plates facing the respective end caps are provided with inset sealing rings which seal axially against the respective tube ends.

7. A tube bundle heat exchanger substantially as hereinbefore described with reference to Figs. 1 and 2 or Fig. 3 of the accompanying drawings. -.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tube plate 5 comprises a plate 6 facing the jacket, a plate 7 facing the respective end cap 3 and a spacer 8 fixed to the plate 7 in this embodiment. In an alternative embodiment, the spacer 8 may be clamped removably between the two plates 6 and 7. The double plate 5 is clamped in a manner known per se between the jacket 1 and the respective end cap 3 by means of a flange connection including clamping bolts 9 and is sealed by seals 10 and 11. The tubes 12 of the tube bundle are radially sealed in the tube plate 6 by means of glands 13 and packing cord 17. Flexible sealing rings 14 are mounted on the ends of the tubes 12. In the embodiment illustrated here, the sealing rings 14 each have an annular recess therein to receive the end of the respective tube 12.Internally screw threaded holes are provided in the plate 7 in alignment with the tube receiving holes in the plate 6. Externally screw threaded bushes 15 are engaged in the screw threaded holes in the tube 7 and are sealed therewith by means of permanently flexible sealing material. The end face 16 of each threaded bush 15 which faces the plate 6 abuts against the respective sealing ring 14 to compress the latter and thereby produce the necessary axial sealing force. The following advantages are achieved with the above described design: The end or frontal sealing of the tubes relative to the plate 7 produces no radially directed forces at the ends and thus avoids bending stresses which would otherwise lead to fractures. Normal commercial tubing 12 having diameter tolerances in accordance with standard specifications may be used for the tube bundles since diameter variations have no effect upon the pressure tightness as a result of the use of the packing cord seal 17 and seal 14. The longitudinal tolerances for the tubes 12 are compensated for by the adjustability of the bushes 15 in the axial direction relative to the tube 12. Any unavoidable variations in the alignment between the respective holes through the plate 6 and 7 is compensated for because of the sealing of the ring 14 with the end face 16 of the respective bush 15 so that slight mis-alignment between the axis of the bush 15 and the axis of the sealing ring 14 will not destroy the seal between these two parts. Referring now to Fig. 3, the double tube arrangement illustrated therein has a plate 18 which replaces the plate 7 previously described. The plate 18 is pierced with holes and fitted with sealing washers 19 sunk in recesses around the holes. The end faces of the respective tubes 12 engage against the sealing washers 19. In this embodiment, however, it will be appreciated that the tubes 12 must be accurately cut to length. In both of the above-described embodi ments, both the tubes 12 and the jacket 1 are formed of glass. It is also within the scope of the present invention to provide the following constructions: 1. A heat exchange which is provided at both ends with the plate 7 with threaded bushes 15, 2. A heat exchanger provided at one end with the plate 7 and threaded bushes 15 and at the other end with the plate 18 with inset sealing rings 19 and 3. A heat exchange provided at both ends with plates 18 within said sealing rings 19. WHAT WE CLAIM IS:

1. A tube bundle heat exchanger comprising a jacket, end caps for the jacket, a tube bundle mounted within the jacket, a double tube plate assembly disposed at each end of the tube bundle, and seals between the individual tubes and each assembly, wherein the seal between each tube and the tube plate which faces the interior of the jacket acts radially on the tube whereas the seal between each tube and the tube plate facing the respective end cap acts axially on the tube.