HK1072803B - Plate heat exchanger with double-walled heat exchanger plates - Google Patents

Description

The invention relates to plate heat transfer devices.

In this type of plate heat exchanger, the double-walled plate heat exchanger plates of the stack are permanently connected to each other, in particular by soldering, and each has two plate elements with a central heat transfer section and a peripheral section raised to the level of the central heat transfer section. Between the double-walled plate heat exchanger plates, separate flow spaces are formed for at least two heat exchanger fluids. The separate flow gear passes through at least two heat exchanger plates to pass through different heat transfer elements, each located on a steady side of the central heat transfer section. The two central heat exchanger plates are connected to each other in a narrow and highly efficient area.

The double-walled formation of the heat transfer plates ensures an increased safety standard, since even if a leak occurs in one of the two plate elements of a heat transfer plate, the mixing of at least two heat exchanger fluids is prevented, provided that the second plate element of the heat transfer plate does not leak at all.

In order to make the damage visible to monitoring and operating personnel outside the plate heat exchanger in the event of a leak in one of the plate elements, the two plate elements of a double-walled heat exchanger plate shall be placed in the area of the central heat transfer section and the raised edge of the system so that heat exchanger fluid, which, due to the leak in one of the plate elements between the two plate elements, reaches the raised edge sections, can be carried through an opening between the raised edge sections, thus leaking heat exchanger air which escapes through the leak, is carried outwards in the area of the heating plate edge, visible.

The outer edges of the two plate elements of each plate are arranged close together, whereas the outer edges of adjacent plate elements belonging to two heat transfer plates placed close together in the stack are spaced apart. This type of edge design is intended to help to prevent the welding of the two plate elements of the double-walled heat transfer plate, which are placed close together in the stack, by preventing the transfer of heat from the liquid liquid between the two plate elements, which could otherwise be held in the outer edge of the stack, and to prevent the heat from flowing through the different elements of the stack, which would otherwise be placed in the outer edge of the stack, which would otherwise be in the opposite direction of the heat transfer plate.

Document GB647 678 A shows a heat exchanger which is formed by a stack of several heat exchanger plates arranged one above the other, the heat exchanger plates arranged so that between them there are first and second flow spaces.

Document DE 36 00 656 also reveals a heat exchanger made of several heat exchanger plates, in which the heat exchanger surface of each heat exchanger plate is washed on one side with one heat exchanger and on the other side with another heat exchanger.

Document US-B1-6 478 081 describes a heat exchanger consisting of a stack of heat exchanger plates separating first flow spaces for a first heat exchanger fluid and second flow spaces for a second heat exchanger fluid.

The purpose of the invention is to specify an improved plate heat exchanger with a stack of double-walled heat exchanger plates, which facilitates leak detection. The invention includes the idea of a plate heat exchanger with a stack of double-walled heat exchanger plates, permanently connected to each other and each having two plate elements with a central heat transfer section and a peripheral section raised to the level of the central heat transfer section, separated by flow spaces for at least two heat exchanger plate meta-fluids between the double-walled heat exchanger plates, the two central heat exchanger plates being connected in such a way that the central heat exchanger element is at least partially connected to the central heat exchanger and the peripheral elements are at least partially connected, but the heat exchanger plates are not connected, so that the heat exchanger plates are at least partially connected in the high-voltage area between the central heat exchanger and the peripheral heat exchanger, which is at least one-half of the height of the heat exchanger.The outer edges of the two plate elements of the double-walled heat transfer plates are spaced apart, so that the heat exchanger fluid which, as a result of a leak in one of the two plates of a double-walled heat transfer plate, passes between the two plate elements is already visible when a leakage control of the plate heat transfer plate is performed in an outlet area in which the raised edge sections of the two plate elements are close together.when, as a result of the leakage between the plate elements of the heat transfer plate, the heat exchanger fluid only enters a small area which does not lead to the escape of the heat exchanger fluid in the area of the outer edges, which makes it possible to detect already minor leaks from the outside when monitoring the plate heat transfer plate.

The invention may be designed in such a way that the outer edges of adjacent plate elements of two double-walled heat transfer plates placed in a stack side by side are arranged close together, thus facilitating the stack-like storage of several double-walled heat transfer plates at a given distance from each other.

In order to design the separate flow spaces for the at least two heat exchanger fluids appropriately, a preferred embodiment of the invention is to have adjacent double-walled heat transfer plates fluid-tightly connected together along adjacent elevated peripheral sections.

The invention is explained in more detail below by means of illustrations showing: Figure 1 a schematic representation of several plate heat exchangers;Figures 2a and 2a a plate heat exchanger in front and side view respectively; andFigure 3 an intersection of a peripheral area of the plate heat exchanger along a line AA' in Figure 2a.

Figure 1 shows a schematic representation of several successive heat transfer plates 1, 2, 3, 4 each with passageways 5, 6, 7, 8. The heat transfer plates 1-4 are each constructed as a double-walled heat transfer plate with two plate elements coming close together at least in a central heat transfer unit 9 to ensure efficient heat transfer between at least two heat exchanger fluids, the interconnection of the passageways at least 5-8 separate flow spaces in a base of the upper multiple-walled heat transfer plates 1-4 with the help of heat transfer plates. The two plate plates are arranged so that the two main heat transfer plates are connected by means of a radial connection and are arranged in a way that the two heat transfer plates are connected by means of a radial connection. The two heat transfer plates 1-4 can be arranged in two different ways according to Figure 1-10 in order to provide a 180° transition. The two heat transfer plates are arranged in such a way that the two heat transfer plates are connected by means of two radial connections.

Figures 2a and 2b show a schematic representation of a plate heat exchanger 20 with several stacked double-walled plate heat exchanger of the type shown in Figure 1 in a front and side view respectively.

Figure 3 shows a cross section of the plate heat exchanger 20 in Figure 2a along a line AA. Of the several double-walled plate heat exchanger 20 examples are shown in Figure 3 the plate heat exchanger 30 and 31, each with two plate elements 33, 34 The two plate elements 33, 34 are joined in a central heat exchanger 35 which continues in a central central heat exchanger 35 to the level of the central heat exchanger 35 in a region of the respective elevated peripheral section 36.

In contrast, between the outer rows 33a, 34a of the heat transfer plate 30, 31 and 32 respectively, an interval 37 has already been formed so that the outer edges 33a, 34a are separated, so that a capillary-breaking image is obtained. This is a method of operation for heat transfer between the two heat transfer plates 33, 34 and 31, which is achieved by a heat transfer element operating in a zone between the two heat transfer plates 31, 33, 34 and 32.

In the case of heat transfer plates 30, 31, 32 adjacent heat transfer plates 30 and 31 and 31 and 32 respectively are welded together in the area of the respective raised edge sections 36 by soldering material 39; the soldering material 39 can be soldered by capillary action to a terminal section 40 between the outer edges 33a, 34a.

The design described in the outer edge area 33a, 34a may be provided for all or part of the double-walled heat transfer plates of a plate heat transfer unit.

Claims (3)

1. A plate-type heat exchanger comprising a stack of double-walled heat exchanger plates (30 - 32) which are permanently interconnected and each include two plate members (33, 34) having a central heat transfer portion (35) and an edge portion (36) bent upwardly with respect to the plane of the central heat transfer portion (35), separate flow passage spaces for at least two heat exchange fluids being defined between the double-walled heat exchanger plates (30 - 32), the two plate members (33, 34) entering into close mutual engagement at least partly in the area of the central heat transfer portion (35) and the upwardly bent edge portion (36) yet permitting heat exchange fluid between the plate members which gets to the upwardly bent edge portions (36) to exit through an aperture between the upwardly bent edge portions (36), the upwardly bent edge portions (36) being formed respectively with an outer edge (33a, 34a), characterized in that the respective outer edges (33a, 34a) of the two plate members (33, 34) of the double-walled heat exchanger plates (30 - 32) are spaced from each other.
2. The plate-type heat exchanger as claimed in claim 1, characterized in that outer edges (33a, 34a) of adjacent plate members (33, 34) of two neighboring double-walled heat exchanger plates (30, 31; 31, 32) in the stack are disposed in close mutual engagement.
3. The plate-type heat exchanger as claimed in claim 1 or 2, characterized in that neighboring double-walled heat exchanger plates (30, 31; 31, 32) are interconnected in fluid-tight fashion along adjacent upwardly bent edge portions (36).