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GUIDE TO MEASUREMENT OF ROTATING EQUIPMENT

Mechanical seals are never sold separately; they are always part of a larger rotating machinery assembly. Obviously, if the seal is to work properly, the design of the seal installation must be based on correct dimensions and information encompassing all aspects of the spinning equipment that affect the seal. In many cases, this information may be obtained reliably from drawings, but in some cases, taking measurements of the actual equipment in the field is the only option. 

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Because rotating equipment is so different in design, it is impossible to create a document guide that covers all of the designs that may be encountered in the field. Rather, this document addresses standard measurements for a typical centrifugal pump, but it also mentions other types of equipment in passing.

The shaft of the equipment determines the position of all the spinning components of the seal assembly, either through a close clearance shaft sleeve or directly to a retainer/collar, for example. It is also a component of a static or dynamic seal (for example, a sleeve o-ring / trapped gasket / secondary seal, etc.).

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For stepped shafts, all important diameters in the seal chamber area, both inboard and outboard of the seal, must be measured. When designing a hooked sleeve, take note of the position of the hooked step, the minor diameter, and the keyway. The shaft's primary diameter should have a sufficient lead-in chamfer (usually 1.5mm long X 20o) to allow the sleeve / sleeve o-ring / secondary seal to be readily placed onto the shaft during seal installation. If this is not available, the end-user should be asked to change the shaft.

CONTENTS IN GUIDE TO MEASUREMENT OF ROTATING EQUIPMENT

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1.0 INTRODUCTION 

2.0 SOURCES OF EQUIPMENT DIMENSIONS 

3.0 WHERE TO TAKE DIMENSIONS 

4.0 RECORDING DATA 

5.0 MEASURING EQUIPMENT & ACCURACY 

6.0 MEASUREMENTS & CHECKS 

7.0 RETROFITS - REUSING EXISTING SEAL PARTS 

8.0 UPGRADES FROM GLAND PACKING 

9.0 DOUBLE SEALS 

10.0 PRE-COMMISSIONING EQUIPMENT CHECKS 

11.0 OTHER EQUIPMENT

12.0 STUFFING BOX & SLEEVE DATA SHEET 

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