ROUTINE REPAIR PROCEDURES.

 

  • Introduction

The following is a description of the routine repair procedures, engineering. test and inspection specifications used to insure that each valve repaired conforms to the high standards of quality that our customers demand.

 

  • Disassembly-Cleaning-Inspection

Every valve is initially dismantled and thoroughly cleaned by shot blasting. Each part is then thoroughly inspected for adequate wall thickness, pitting, worn or corroded parts according to the Quality Standard for Steel Castings--visual method MSS SP55.

 

  • Machining

After disassembly and cleaning the Range faces or bun well ends are remachined to conform to the appropriate standard. The Range on iron valves are remachined to conform to the American National Cast Iron Flange Standard (ANSI 816.1) and refaced to conform to MSS SP-6. Steel valve Ranges up to 24" are remachined to conform to the American National Steel Flange Standard (ANSI 816.5) and refaced to conform to MSS SP-6. Steel valves over 24' are remachined to the MSS SP44 Steel Pipeline Flange Standard. The butt weld ends for cast steel valves are remachined to comply to ANSI 816.25. Any steel valves with ring type joint Ranges are remachined to ANSI 816.20 Standards.
The seating surface of each type of valve is then inspected for integrity and proper alignment before being polished to insure a tight seal.

 

  • Assembly

As the components of each valve are reassembled, new packing and gaskets are selected according to customer specification if given or according to the pressure and temperature requirements of the valve otherwise. The chart in Figure 3 gives technical data on some of the more common valve stem packings and their applications.
Bolting is inspected and replaced (if necessary) according to ASTM A193 and ANSI 81.1, 2A fit, for steel valves and  Alloy valves. Nuts are furnished when needed according to ASTM 194 and ANSI Bl.l, 28 fit, for steel valves. Nuts for Alloy valves conform to ASTM A193 B7, or B16 for ferritic Alloys and B8 or B8M for austenitic Alloys. All nuts replaced conform to ANSI 818.2.2 hexagon dimensions.

 

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