Checking heat exchanger tubes with an eddy-current integrity test

• US 5,883,512 A
• Filed: 10/25/1996
• Issued: 03/16/1999
• Est. Priority Date: 12/14/1995
• Status: Expired due to Term

• Current Assignee: Areva NP GmbH (AES Corporation)
• Original Assignee: Siemens AG
• Inventors: Streit, Klaus, Ammann, Franz
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US08/740,255
• Time in Patent Office: 872 Days
• Field of Search: 324/220, 324/225, 324/228, 324/262, 324/219, 324/234, 324/238
• US Class Current: 324/220
• CPC Class Codes: F26B 5/04 by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum F26B11/049 and F26B17/128 take precedence
• CPC Class Codes: G01N 1/286 involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising microtomes G01N1/06; pulverising in general B02C; mixing in general B01F
• CPC Class Codes: G01N 27/9006 Details, e.g. in the structure or functioning of sensors

Abstract

A method for checking heat exchanger tubes of metallic material includes drying inner surfaces of the heat exchanger tubes. A compressed air-abrasive mixture is then led through the heat exchanger tubes. An eddy-current integrity test of the heat exchanger tubes is then performed.

Claims

1. A method for checking heat exchanger tubes of metallic material, which comprises:

drying inner surfaces of heat exchanger tubes;

then leading a compressed air-abrasive mixture through the heat exchanger tubes; and

then performing an eddy-current integrity test of the heat exchanger tubes.

2. The method according to claim 1, which comprises carrying out the step of drying the inner surfaces of the heat exchanger tubes by at least one of evacuation and circulation of dried air.

3. The method according to claim 1, which comprises leading the compressed air-abrasive mixture through the heat exchanger tubes for a period of between 1 minute and 10 minutes.

4. The method according to claim 1, which comprises adjusting a pressure of the compressed air in the compressed air-abrasive mixture when entering the heat exchanger tubes to be between 0.1 MPa (1 bar) and 1 MPa (10 bar).

5. The method according to claim 1, which comprises forming the abrasive in the compressed air-abrasive mixture of particles having a shape selected from the group consisting of granular, spherical, cubic and parallelepipedal.

6. The method according to claim 1, which comprises forming the abrasive in the compressed air-abrasive mixture of a substance selected from the group consisting of glass, corundum, high-grade steel, ceramic and material of the heat exchanger tubes.

7. The method according to claim 1, which comprises forming the abrasive in the compressed air-abrasive mixture of particles having a diameter between 100 μ

m and 1000 μ

m.

8. The method according to claim 1, which comprises forming the abrasive in the compressed air-abrasive mixture of particles having a diameter between 150 μ

m and 300 μ

m.