# US 8,782,888 B2 · Method for repairing plate heat exchangers

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- Number: US 8,782,888 B2
- Document ID: US8782888B2
- Status: Granted
- Kind: B2
- Application number: 12/989,674
- Filed: 2009-04-08
- Published: 2011-10-27
- Granted: 2014-07-22
- Earliest claimed: 2008-04-28
- Assignees: L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
- Applicants: Bernard Saulnier; Jean-Pierre Tranier; François Fuentes; Sophie Deschodt
- Inventors: Bernard Saulnier; Jean-Pierre Tranier; François Fuentes; Sophie Deschodt
- Web page: https://patentgrep.com/patent/US8782888B2

## CPC

- F28D 9/0062: {the conduits for one heat-exchange medium being formed by spaced plates with inserted elements (F28D9/0012, F28D9/0025, F28D9/0081, F28D9/04 take precedence)}
- F28F 11/00: Arrangements for sealing leaky tubes and conduits (stopping flow from or in pipes in general F16L55/10)
- F28D 2021/0033: {for cryogenic applications}
- Y10T 29/49352: Repairing, converting, servicing or salvaging
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method for repairing a plate heat exchanger of the type comprising a plurality of plates which, together with side bars arranged on the plates, define fluid flow paths is presented.

## Claims

### Claim 1

A method for repairing a plate heat exchanger of the type comprising a plurality of plates which, together with side bars arranged on the plates, define fluid flow paths, one of which paths has a leak to an adjacent path, the method comprising at least the following successive steps:
isolating the two adjacent paths; and
injecting an injection fluid at a pressure of between 0.5 bar and 1.5 bar into the two adjacent paths,
wherein the two adjacent paths are isolated from the remainder of the heat exchanger such that the injection fluid is within only the two adjacent paths during operation.

### Claim 2 (depends on 1)

The method of claim 1, wherein after having isolated the two adjacent paths, a header is arranged on the side bars of the two adjacent paths, thus allowing the injection fluid to be injected into said adjacent paths.

### Claim 3 (depends on 1)

The method of claim 1, wherein the injection fluid injected into the two adjacent paths is an inert gas.

### Claim 4 (depends on 1)

The method of claim 1, wherein the injection fluid injected into the two adjacent paths is nitrogen gas.

### Claim 5 (depends on 1)

The method of claim 1, wherein the heat exchanger is an evaporator-condenser of an air separation unit.

### Claim 6 (depends on 1)

The method of claim 1, wherein the injection fluid does not condense within the two adjacent paths during operation.

### Claim 7 (depends on 1)

The method of claim 1, wherein the injection fluid does not react with other fluids flowing through the heat exchanger during operation.