GB2167175A

GB2167175A - Heat exchanger

Info

Publication number: GB2167175A
Application number: GB08431098A
Authority: GB
Inventors: Donald Andrew Cross
Original assignee: APV International Ltd
Current assignee: APV International Ltd
Priority date: 1984-11-21
Filing date: 1984-12-10
Publication date: 1986-05-21
Also published as: GB8429359D0; GB8431098D0

Abstract

A heat exchanger is made up by the formation of sub-assemblies of plate (1,2,3) and spacer (1a,1b,2a,2b,3a,3b) and building up a pack of such sub-assemblies by successively welding through the plate to secure the plate (2,3) to the spacer (1a,1b,2a,2b) of the preceding sub-assembly. For this purpose, it is necessary for the peripheral spacers (1b,2b,3b) to be successively offset from each other for access to be obtained for through-the-plate welding. in accordance with the present invention, the successive peripheral spacers (1b,2b,3b) overlap, leading to increased strength of the pack and also to an economy in plate size for a required area of the heat exchange zone. <IMAGE>

Description

SPECIFICATION Heat exchanger This invention relates to heat exchangers, and more particularly to a method of manufacturing a plate type heat exchanger with the plates welded together to form a permanently assembled pack of plates.

Our co-pending application 8225498, which was published under No. 2126703, describes and claims a method of manufacturing a heat exchanger comprising a pack of plates welded into a pack in spaced face-to-face relationship to define flow spaces between adjacent plates, the plates having aligned apertures forming supply and discharge ducts for heat exchange media, in which two types of plates and spacer sub-assembly are formed by sealingly securing spacers to one side of the plate by welding through the plate, the sub-assemblies of a first type having a peripheral spacer extending on a line around the flow space and outside all of the duct-forming apertures and aperture-sealing spacers surround one pair of the apertures to isolate those apertures from the flow space bounded bgy the peripheral spacer, the sub-assemblies of the second type having a peripheral spacer passing outside the apertures aligned with the said one pair of apertures in the sub-assemblies of the first type to allow these to communicate with the flow space, and a pair of aperture-sealing spacers around the other pair of apertures to isolate them from the flow space, the lines of the peripheral spacers being such that, when a sub-assembly of one type is assembled next to a sub-assembly of the other type with the aperture aligned and only one set of spacers between the plates, the lines of the peripheral spacers do not intersect, and building up a stack of sub-assemblies by adding sub-assemblies of the different types alternately and welding through the plate to the spacers of the preceding sub-assembly to form continuous and sealing welds. It also claims heat exchangers manufactured by such a method.

It has now been found that the peripheral spacers may in fact overlap, provided that there is sufficient offset between the spacers to make a weld through the plate to the spacers of the preceding sub-assembly. By overlapping the spacers, the amount of space occupied by the peripheral spacers may be reduced, thus reducing the width of the plates and reducing cost.

Accordingly the present invention consists in a method of manufacturing a heat exchanger comprising a pack of plates welded into a pack in spaced face-to-face relationship to define flow spaces beween adjacent plates, the plates having aligned apertures forming supply and discharge ducts for heat exchange media, in which two types of plate and spacer sub-assembly are formed by sealingly securing spacers to one side of the plate by welding through the plate, the sub-assemblies of a first type having a peripheral spacer extending on a line around the flow space and outside all of the duct-forming apertures and aperturesealing spacers surround one pair of the apertures to isolate those apertures from the flow space bounded by the peripheral spacer, the sub-assemblies of the second type having a peripheral spacer passing outside the apertures aligned with the said one pair of apertures in the sub-assemblies of the first type to allow these to communicate with the flow space, and a pair of aperture-sealing spacers around the other pair of apertures to isolate them from the flow space, the lines of the peripheral spacers being offset such that, when a sub-assembly of one type is assembled next to a sub-assembly of the other type with the apertures aligned and only one set of spacers between the plates, the lines of the peripheral spacers in adjacent sub-assemblies are sufficiently offset that a weld can be made through the plate to the spacer of the preceding sub-assembly, and building up a stack of sub-assemblies by adding sub-assemblies of the different types alternately and welding through the plate to the spacers of the preceding sub-assembly to form continuous and sealing welds, wherein the spacers in the successive sub-assemblies overlap.

The invention also consists in a heat exchanger when made by a method in accordance with the invention as set forth above.

The invention will be further described with reference to the accompanying drawing, of which the single figure is a sectional view similar to part of Fig. 3 of the co-pending application 8225498 (Serial No 2126703) showing a modification in accordance with the present invention, and showing the plates somewhat separated.

For a fuller understanding of the method of which the present invention is a modification, reference should be made to that co-pending application 8225498, and the contents of the specification of that application are imported hereinto by reference.

The accompanying drawing shows parts of three successive sub-assemblies of plates 1, 2 and 3 respectively, with their aperture-sealing and peripheral spaces 1a and 1b, 2a and 2b, and 3a and 3b respectively welded to the correspondingly numbered plates to form sub-assemblies as described in the said co-pending application. The apertures are illustrated by the reference numerals 4 and 5 for surrounded and non-surrounded apertures respectively.

In accordance with the teachings of the said co-pending application, the successive sub-assemblies are each welded to the preceding sub-assembly by welding through the plate to the peripheral and aperture-sealing spacers thereof. The weld positions for this are indicated by dotted lines 6 in the drawing. How ever, the plates of successive sub-assemblies do not normally have aligned surrounded apertures 4 with their aperture-sealing spacers, so there is no problem in obtaining access for through-the-plate welding to these. In order to obtain access for through-the-plate welding to the peripheral spacers, the said co-pending application showed the peripheral spacers as being offset by more than their widths.

It will be seen that in the present construction, the peripheral spacers 1 b, 2b and 3b, which are shown in section only, in successive sub-assemblies overlap, but they are offset to such an extent that the plate 2 may be welded successfully by a through-the-plate technique to the peripheral spacer 1 b, without damage to the spacer 2b. Similarly the offset is sufficient to allow through-the-plate welding of the plate 3 to the peripheral spacer 2b, and so forth.

This arrangement is more economical of space, and thus enables the overall width of the plate to be redjced for a given width of flow space.

While one particular amount of overlap has been described and shown, it will be appreciated that different relative proportions between the widths of the spacers and the amount of overlap may be used.

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

Claims

1. A method of manufacturing a heat exchanger comprising a pack of plates welded into a pack in spaced face-to-face relationship to define flow spaces between adjacent plates, the plates having aligned apertures forming supply and discharge ducts for heat exchange media, in which two types of plate and spacer sub-assembly are formed by sealing securing spacers to one side of the plate by welding through the plate, the sub-assemblies of a first type having a peripheral spacer extending on a line around the flow space and outside all of the duct-forming apertures and aperture-sealing spacers surround one pair of the apertures to isolate those apertures from the flow space bounded by the peripheral spacer, the sub-assemblies of the second type having a peripheral spacer passing outside the apertures aligned with the said one pair of apertures in the sub-assemblies of the first type to allow these to communicate with the flow space, and a pair of aperture-sealing spacers around the other pair of apertures to isolate them from the flow space, the lines of the peripheral spacers being offset such that, when a sub-assembly of one type is assembled next to a sub-assembly of the other type with the apertures aligned and only one set of spacers between the plates, the lines of the peripheral spacers in adjacent sub-assemblies are sufficiently offset that a weld can be made through the plate to the spacer of the preceding sub-assembly, and building up a stack of sub-assemblies by adding sub-assemblies of the different types alternately and welding through the plate to the spacers of the preceding sub-assembly to form continuous and sealing welds, wherein the spacers in the successive sub-assemblies overlap.

2. A heat exchanger when made by a method as claimed in claim 1.