JPH0128317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a plurality of plates that are housed in a shell and are placed in contact with each other so that alternating passages for a heat transfer medium and a heat transfer medium are formed between the plates. This relates to a plate heat exchanger. More specifically, improvements to the sealing element which is interposed between the shell inner wall and the plate stack in the so-called plate-and-shell type heat exchanger described above to prevent fluid from passing through the plate stack. It is related to.

In this type of plate heat exchanger, gaps are likely to form between the shell and the plate due to imperfections in the seal. When such a gap occurs, the flow of the fluid supplied into the shell will be different from the normal flow through the fluid passage formed between the plates to the outlet provided in the shell, and the flow between the plate and the shell. The flow passes through the gap between the two and is divided into a flow that passes toward the discharge port and a short pass. Furthermore, if this fluid is steam in the condenser, the short-passed steam passes through the steam passage and reaches the bottom.
In other words, since the pressure is naturally higher than that of the steam that has undergone the condensation process, it tends to flow back into the steam passage through the lower opening of the steam passage. As a result, the flow of steam in the steam passage is obstructed and heat transfer efficiency is significantly reduced.

Conventionally, the sealing element in the problematic area was constructed of an elastic gasket, but if the compressive repulsion force of this gasket was increased in order to eliminate the gap, it was necessary to increase the thickness of the shell for strength reasons. In addition, it was necessary to constantly retighten the gasket in consideration of permanent deformation.

In view of the above-mentioned circumstances, the present invention aims to provide a plate heat exchanger equipped with a sealing element that ensures more reliable sealing.

In this invention, a shell element interposed between a plate and a shell to prevent a fluid from passing through the shell is constructed of a hollow elastic member, and the internal pressure of the hollow elastic member can be adjusted.

Reference will now be made in detail to embodiments of the invention, which are illustrated by way of example only in the accompanying drawings. Although the present invention will be described in the case where it is applied to a condenser, the present invention is applicable not only to condensers but also to a wide range of plate heat exchangers.

In FIGS. 1 to 3, a shell 1 has a steam supply port 2 at the top and a condensate discharge port 3 at the bottom, and accommodates a stacked body 4A of plates 4 therein. The plate 4 has a cooling liquid inlet 5 and an outlet 6 and is suspended within the shell 1 by suitable means (not shown). The plate stack 4A is tightened together with gaskets between the plates, thereby forming alternate fluid passages A and B for both heat exchange media in the gaps between the plates. The coolant inlets and outlets 5 and 6 are aligned and extend perpendicularly to the plane of the drawing, with a supply port 7 and a discharge port 8 provided in the shell 1 at their ends.
A coolant supply passage and a discharge passage leading to the cooling liquid are constructed.

As shown in Fig. 2, the steam passage A is open to the inner space of the shell, but there is a cooling liquid inlet/outlet 5,
6 by gaskets 9 and 10. As shown in FIG. 3, the coolant passage B is closed to the inner space of the shell due to the presence of the gasket 11, and communicates with the coolant inlets and outlets 5 and 6.

When steam is supplied from the steam supply port 2 and cooling liquid is supplied from the coolant supply port 7, these fluids flow as follows. The steam that has entered the shell 1 from the steam supply port 2 flows evenly into each steam passage A from the opening of each steam passage A of the plate stack 4A, and condenses as it flows along the heat transfer surface. However, the resulting condensate flows down into the inner space of the shell 1, and from there passes through the condensate outlet 3 and reaches the outside of the vessel. On the other hand, coolant supply port 7
The coolant supplied from the coolant flows into the coolant passage B from each coolant inlet 5, and flows along the heat transfer surface to the coolant outlet 6.
As the steam passes through the steam passage A, it absorbs heat from the steam in the adjacent steam passage A, and then flows from the outlet 6 to the outside of the vessel via the coolant discharge port 8.

A sealing element interposed between the plate and the shell to prevent shot passage of fluid through the portion is indicated at 12. As can be clearly seen from FIGS. 4 and 5, the sealing element 12 consists of a hollow elastic member 13 having a cavity 14 inside, and the inner wall facing the opening of the steam passage A of the plate stack 4A of the shell 1. It is accommodated in a channel member 15 disposed on the side. The channel member 15 is a member having a U-shaped cross section and opening inward, and the inner surface of the sealing element 12 fitted into the channel member 15 is elastically pressed against the plate 4 and the gasket 11 between the plates, and the shell 1 and the plate laminate 4A are completely sealed so that there is no gap.

Such a complete seal is made possible by, on the one hand, maintaining the pressure within the cavity 14 of the hollow elastic member 13 constituting the sealing element 12 at a suitable level. For example, compressed air can be used as the pressure source. Of course, the internal pressure can be kept constant at all times, but by making it adjustable, it is possible to easily "retighten" the sealing element in response to aging of the elastic member 13, for example. There is no need to increase the thickness of the shell 1 so much.

As explained above, the plate heat exchanger of the present invention is a plate heat exchanger in which a plate laminate consisting of a plurality of plates facing each other is housed in a shell, in which steam from the shell and the plate laminate is heated. A channel member that opens inward is provided on the shell side wall at an intermediate portion in the fluid flow direction between the opening side of the passage and a hollow elastic member whose internal pressure can be adjusted. A sealing element is fitted to prevent the shot passage of liquid, and the inner surface of the sealing element is brought into elastic contact with the opening side of the steam passage of the plate stack, thereby preventing fluid from flowing between the shell and the plate. Not only can short passes be prevented more reliably, it can be easily retightened in response to changes over time, and the shell plate thickness is relatively thin, making it economical, among other benefits. It is something.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of a plate heat exchanger according to the present invention, and FIG. 2 is a schematic cross-sectional view taken along the line --- in FIG. 1, showing a steam passage. 3 is a schematic cross-sectional view similar to FIG. 2 showing a cooling water passage, FIG. 4 is an enlarged cross-sectional view taken along the line --- in FIG. 3, and FIG. 5 is a cross-sectional perspective view of the seal element. 1... Shell, 4... Plate, 12... Seal element.

Claims (1)

[Scope of Claims] 1. In a plate heat exchanger in which a plate stack consisting of a plurality of mutually facing plates is accommodated in a shell, between the shell and the opening side of the steam passage of the plate stack and a channel member opening inward is provided on the side wall of the shell at an intermediate portion in the fluid flow direction, and within the channel member is a hollow elastic member whose internal pressure can be adjusted to prevent the shot path of the fluid. A plate heat exchanger characterized in that a sealing element is inserted and the inner surface of the sealing element is brought into elastic contact with an opening side of a steam passage of a plate laminate.