Jet pump sensing line T-bolt clamp electrode discharge machining tool

• US 6,233,301 B1
• Filed: 09/25/1998
• Issued: 05/15/2001
• Est. Priority Date: 09/25/1998
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Robergeau, Merlene
• Primary Examiner(s): Carone, Michael J.
• Assistant Examiner(s): KEITH, JACK W
• Application Number:
  US09/160,564
• Time in Patent Office: 963 Days
• Field of Search: 376/260, 376/302-304, 376/372, 376/461, 376/463, 219/69.15, 219/69.11, 219/69.17, 219/70
• US Class Current: 376/302
• CPC Class Codes: B23H 9/00 Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects heat treatment by cathodic discharge C21D1/38
• CPC Class Codes: B23H 9/14 Making holes
• CPC Class Codes: G21C 15/25 using jet pumps
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

An electrode discharge machining (EDM) apparatus for machining slots in a jet pump diffuser in a nuclear reactor pressure vessel is described. The apparatus is configured to machine a plurality of slots in the diffuser at positions behind the diffuser sensing line within the plane formed by the center of the diffuser and the sensing line. The apparatus includes a housing, a plurality of clamp assemblies, a hook assembly configured to engage the sensing line standoff so that the apparatus is positioned at an angle from a plane formed by the center of the diffuser and the sensing line, and a plurality of electrode assemblies. The EDM apparatus can be configured to be installed clockwise or counter-clockwise around the sensing line depending on the spacing available around given diffusers. The EDM apparatus is capable of burning a plurality of slots at the same time, thereby saving time and money.

Claims

1. An electrode discharge machining apparatus for machining slots in a jet pump diffuser in a nuclear reactor pressure vessel at positions within a plane formed by a center of the diffuser and a sensing line, the jet pump diffuser having a center, a diffuser sensing line, and a sensing line standoff coupling the sensing line to the diffuser, said apparatus comprising:

a housing;

a plurality of clamp assemblies coupled to said housing;

a hook assembly coupled to said housing and configured to engage a jet pump diffuser sensing line standoff so that said apparatus is positioned at an angle from a plane formed by the center of the diffuser and the sensing line; and

a plurality of electrode assemblies coupled to said housing.

2. An apparatus in accordance with claim 1 comprising two clamp assemblies.

3. An apparatus in accordance with claim 1 comprising two electrode assemblies.

4. An apparatus in accordance with claim 1 wherein said hook assembly is configured to engage the sensing line standoff so that said apparatus is positioned at an angle of 21°

from the plane formed by the center of the diffuser and the sensing line.

5. An apparatus in accordance with claim 4 wherein said hook assembly comprises a flat hook shaped member and a cylindrically shaped member depending from said hook shaped member, said hook shaped member configured to engage the sensing line standoff.

6. An apparatus in accordance with claim 2 wherein each said clamp assembly comprises a clamping arm and an actuation cylinder coupled to said clamping arm by a movable shaft, said clamping arm configured to engage the sensing line.

7. An apparatus in accordance with claim 3 wherein each said electrode assembly comprises an electrode holder movably coupled to said housing and an electrode coupled to said electrode holder, said electrode configured to form a slot in the diffuser.

8. An electrode discharge machining apparatus for machining slots in a jet pump diffuser in a nuclear reactor pressure vessel at positions within a plane formed by a center of the diffuser and a sensing line, the jet pump diffuser having a center, a diffuser sensing line, and a sensing line standoff coupling the sensing line to the diffuser, said apparatus comprising:

a housing;

two clamp assemblies coupled to said housing;

a hook assembly coupled to said housing and configured to engage a jet pump diffuser sensing line standoff so that said apparatus is positioned at an angle from a plane formed by the center of the diffuser and the sensing line; and

two electrode assemblies coupled to said housing.

9. An apparatus in accordance with claim 8 wherein said hook assembly is configured to engage the sensing line standoff so that said apparatus is positioned at an angle of 21°

from the plane formed by the center of the diffuser and the sensing line.

10. An apparatus in accordance with claim 9 wherein said hook assembly comprises a flat hook shaped member and a cylindrically shaped member depending from said hook shaped member, said hook shaped member configured to engage the sensing line standoff.

11. An apparatus in accordance with claim 8 wherein each said clamp assembly comprises a clamping arm and an actuation cylinder coupled to said clamping arm by a movable shaft, said clamping arm configured to engage the sensing line.

12. An apparatus in accordance with claim 8 wherein each said electrode assembly comprises an electrode holder movably coupled to said housing and an electrode configured to be coupled to said electrode holder and to form a slot in the diffuser.