GB2151347A

GB2151347A - Plate heat exchangers

Info

Publication number: GB2151347A
Application number: GB8332883A
Authority: GB
Inventors: Aubrey Derek Barker
Original assignee: APV International Ltd
Current assignee: APV International Ltd
Priority date: 1983-12-09
Filing date: 1983-12-09
Publication date: 1985-07-17
Also published as: GB8332883D0

Abstract

A pack of plates 3 of the plate heat exchanger is enclosed between a base 4 and a closure member 6 separated by side walls integral with the base 4. The deflections due to internal pressure of a box section are less than those with the conventional slab section head and follower and the provision of two side walls also restrains the plates against lateral movement and partially encloses the heat exchanger. As illustrated in Fig. 4, the pack of plates 3 may be compressed by means of a moveable follower 11 using tightening screws reacting against the enclosure 6. Other embodiments are illustrated. <IMAGE>

Description

SPECIFICATION Plate heat exchanger and support therefor This invention relates to plate heat exchangers and to supports for plate heat exchangers.

A plate heat exchanger comprises a pack of metal plates, usually corrugated to improve their strength and the heat transfer characteristics, defining fluid flow spaces between adjacent plates. The boundaries of the flow spaces are defined by gaskets arranged at the edges of the plates and further gasketing controls communication between the flow spaces and supply and discharge ducts for heat exchange media. Such ducts are normally formed by holes in the plates aligned through the pack.

It is conventional for the pack of plates to be mounted and compressed in a frame comprising a fixed head and end member and top and bottom rails extending between the head and end member. The plates are suspended from the top rail and the pack of plates is compressed between the fixed head and a moveable follower, also mounted on the top rail. Connections to the ducts are normally through the head and sometimes, particularly for multi-pass operation, through the follower as well. In order to obtain and maintain compression of the pack of plates, resort is frequently made to the use of tiebars extending between the head and follower. With modern technology, the pressures involved are high and the head and follower have to be massive slabs of metal which are expensive to fabricate and difficult to handle during installation and maintenance of the heat exchanger.

Despite this, the plate heat exchanger is in wide commercial use.

It is an object of the present invention to provide an improved form of support for a plate heat exchanger and a plate heat exchanger incorporating such a support. In accordance with a first aspect of the present invention, there is provided a plate heat exchanger comprising a compressed or compressible pack of heat exchanger plates, the pack of plates being mounted in an enclosing support comprising a base, integral side walls and a closure member extending between the side walls and opposed to the base, and pack of plates being held compressed, in use, between the base and closure member of the enclosing support.

The closure member may be integral with the side walls so as to form a box section enclosing support. In an alternative, the closure member is such that the base and side walls form a channel section and the closure member is a moveable follower adapted to be secured in position to hold the pack compressed.

In the box section arrangement, standard box sections may be used, thereby significantly reducing the overall cost of the plate heat exchanger. Also, non-standard sections could be used, for instance having the long sides, forming the base and closure member, somewhat thicker than the short sides forming the side walls.

It will be appreciated that the deflections arising from internal pressures in the box section are considerably less than those arising in the head and follower of a conventional plate heat exchanger, thus resulting in a requirement for reduced thicknesses of metal.

The thinner sections thus arising improve the economics of the use of materials such as stainless steel for the box or channel sections rather than the conventional clad mild steel as is used for the head follower in most cases.

The use of side walls to contain the plates results in improved lateral location so that the conventional arrangement of hanging eyes and top bars become unnecessary. Further, if the ends of the box section are sealed, the whole heat exchanger may be enclosed so that leakage of hazardous fluids can be more readily contained, thus resulting in improved safety in operation.

The invention will be further described with reference to the accompanying drawings, which show various embodiments of the invention, and in which: Figure 1 is a prospective end view showing part of a box section enclosing support with a pack of plates shown schematically therein: Figure 2 is a similar view showing a channel section support with a movable closure member; Figures 3 (a), 3 (b), and 3 (c), are each sections showing respective stages in compression of the plate pack according to one mode of procedure; Figure 4 is a sectionai view showing an alternative mode of compressing the plate pack with a box section; and Figure 5 shows an arrangement for compressing the plates using a channel section with moveable closure.

Turning first to Fig. 1, there is shown a box section enclosing support 1, which is shown inverted to illustrate the provision of apertures 2 connected with supply and discharge ducts in the pack of plates 3. The apertures 2 are provided in the base 4 of the box shaped section and the section also includes side walls 5 integral with the base 4 and an opposed closure 6 also integral. As illustrated, the box section is shown as having a common wall thickness for all four sides of the section, but it is feasible for the side walls 5 to be somewhat thinner than the base 4 and closure 6.

Fig. 2 shows an alternative arrangement in which a base 4 and side walls 5 form a channel section and in which the plates 3 are compressed by a moveable closure 7 of slab form.

Turning now to Figs. 3(a), 3(b), and 3(c), the Fig. 3(a) shows a box section support of the Fig. 1 type with the pack of plates 3 in an uncompressed on partially compressed state.

Fig. 3 (b) shows how by introduction of a wedge member 8 and rigid packing material 9, the plates can be compressed by driving the wedge member 8 between the plates 3 and the closure 6, until the position of Fig. 3 (c) is reached in which the packing 9 is fully introduced between the plates and the closure 6. The wedge is separate from the packing and is removed for re-use once this stage is reached.

In an alternative arrangement as shown in Fig. 4, the closure 6, which is integral with the box section is used rather in the manner of a conventional end member of a heat exchanger frame and the actual compression of the pack of plates 3 is achieved by means of a moveable follower 11 which is used to compress the plates by means of tightening screws 1 2 or other tightening means reacting against the closure 6.

Where the closure 7 is moveable as in Fig.

2, then it needs to be secured to the channel section formed by the base 4 and side walls 5. This may for instance be achieved by compressing the plates and then subsequently welding the closure 7 in position. In an alternative, the closure may be held in the compressed position by bearing directly upon retaining bars which are welded in position across the channel behind the closure 7. In the method illustrated in Fig. 5, retaining bars 1 3 are welded across the top of the channel section at intervals along its length, and these retaining bars 1 3 carry tightening screws 1 4 which may be used to compress and hold the closure member 7 against the plates 3.

Various modifications may be made within the scope of the invention.

Claims

1. A plate heat exchanger comprising a compressed or compressible pack of heat exchange plates, the pack of plates being mounted in an enclosing support comprising a base, integral side walls and a closure member extending between the side walls and opposed to the base, the pack of plates being held compressed, in use, between the base and closure member of the enclosing support.

2. A plate heat exchanger as claimed in claim 1, in which the closure member is integral with the side walls to form a box section enclosing support.

3. A plate heat exchanger as claimed in claim 2, in which packing is inserted between the closure member and the pack of plates to maintain compression of the pack.

4. A plate heat exchanger as claimed in claim 3, in which the packing is inserted behind a wedge member which acts to compress the pack of plates.

5. A plate heat exchanger as claimed in claim 2, in which a moveable follower is mounted in the box section and is pressed on to the plates by tightening means reacting against the closure member.

6. A plate heat exchanger as claimed in claim 1, in which the base and integral side walls form a channel section and the closure member is in the form of a moveable follower which is secured in position to hold the pack compressed.

7. A plate heat exchanger as claimed in claim 6, in which the moveable follower is secured by restraining bars welded across the channel section behind the follower.

8. A plate heat exchanger as claimed in claim 7, in which tightening screws act between the restraining bars and the follower.

9. A plate heat exchanger as hereinbefore described with reference to the accompanying drawings.

10. A support for a plate heat exchanger comprising a base and integral side walls, the base having connections therethrough for communication with supply and discharge ducts in a pack of plates mounted in the support, the support also comprising a closure member extending between the side walls and opposed to the base in order to hold the back plate compressed between the closure member and the base.

11. A support as claimed in claim 10 in which the closure member is integral with the side walls to form a box section enclosing support.

1 2. A support as claimed in claim 11, comprising a moveable follower mounted in the box section and arranged to be pressed on to the pack of plates by tightening screws reacting against the closure member.

1 3. A support as claimed in claim 10, in which the base and integral side walls form a channel section, and the closure member is in the form of a moveable follower which is secured in position to hold the pack compressed.

14. A support as claimed in claim 1 3, in which the moveable follower is adapted to be secured by restraining bars welded across the channel section behind the follower.

15. A support as claimed in claim 14, in which tightening screws are arranged between the restraining bars and the follower.

1 6. A support for a plate heat exchanger, substantially as hereinbefore described with reference to the accompanying drawings.