Double-walled plate heat exchanger

Abstract

A double-walled plate heat exchanger and method of managing the same includes a first plate including a first skin, a second skin, at least two port holes, and a leakage escape path between the first and second skins for allowing leaked fluid to exit the double-walled plate heat exchanger, the leakage escape path being in contact with a leakage orifice in one of the skins, and an outer edge of the double-walled plate heat exchanger, the first plate further including a second plate in contact with the second skin.

Description

FIELD OF THE INVENTION[0001]The present invention relates to double-walled plate heat exchangers.BACKGROUND OF THE INVENTION[0002]Plate heat exchangers are used in many process fields where a fluid in a liquid or gas form is heated or cooled to a suitable temperature during continuous flow through the plate heat exchanger. When a fluid is to be heated, it is caused to flow through a small passage in the plate heat exchanger, the passage having a large thermal contact face exposed to a heat-emitting fluid which preferably passes through the plate heat exchanger in counterflow to the fluid for heating. When a fluid is to be cooled, the other fluid in the heat exchanger is heat-absorbing.[0003]FIG. 1 is a schematic of a conventional single-walled plate heat exchanger 1. FIG. 1 shows five rectangular plates 10a-10e, generally referred to as plate 10, which is typically just a small part of the total number of plates of the plate heat exchanger 1. Each of the plates 10 has four port hole...

AI Technical Summary

Benefits of technology

[0018]Embodiments of the present invention advantageously provide a plate heat exchanger with multi-layered plates which provides drainage of fluid that accumulates between plates, prevents cross-contamination of fluids, and allows inspection of the heat exchanger for leaks.

Problems solved by technology

One problem that may arise with respect to one of the above-described designs, is one of these inner plates, 10b-10d can develop an unintended perforation, e.g., a hole or a crack, in the zone transferring heat from the hot medium to the cold medium.

The aforementioned perforation may allow the higher-pressure medium to pass through the perforation into the lower-pressure medium, which is not desirable.

For example, the higher pressure medium may be glycol and the lower pressure medium may be potable water, resulting in the contamination of the potable water with the toxic glycol.

If there is an unintended perforation in the heat transfer area, the medium in that area penetrates the perforation and enters the space between the two skins and leaks out to the atmosphere.

The drawback with the above is that the two skins have been joined permanently, so that the space between the skins cannot be inspected.

This drawback is significant for most applications and rather serious for fluid foods.

However, because the two skins are in close contact, any leakage into the space between the skins does not easily reach the external edge of the plate heat exchanger 1 for easy observation by the process operator, which means the process operator may not be properly alerted to a problem.

This has significant drawbacks, as one sealing potion envelopes the other.

In such a scenario, a gasket leak across the port hole gasket 24 can cause cross contamination.

Secondly, because of the compressive loads exercised by port hole gaskets 24, the location of the peripheral sealing gasket-carrying grooves is inappropriate, as it is not possible to properly inspect the plate heat exchanger 1 for leaks, or to know which plate 10 has a leak.

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