Flowserve 50165 Nordstrom Figure - Manual (Page 20)

Nordstrom Figure 50165 and 50169 Dynamic Balance Iron Plug Valve FCD NVENIM2006-00 – 09/05
20
When You Call or Write...
Be sure you provide the correct information and/or part numbers for your Dynamic Balance plug valve.
Over the years there have been design changes due to our continuing effort make a great valve even
better. It is very important that we are provided the information necessary to correctly identify your
valve.
The following information, located on the valve Nameplate, is required to ensure the correct information
and/or parts are provided for your valve:
1. The valve Size and Figure Number (including any prefixes or suffixes).
2. The Bill of Material Number.
Introduction
The maintenance procedures outlined in this manual are designed to help you reestablish quick and
easy operation, drop-tight shutoff, and a long service life of your Dynamic Balance plug valves.
Some procedures listed in this manual can be performed with the valve in-line and under pressure while
others require that the valve be removed from line pressure. Those procedures that require the valve to
be removed from line pressure will be so noted.
Pressure can become trapped in the valve body cavity even after line pressure has been removed.
Before removing pressure-retaining parts, be sure to:
• Cycle the valve once line pressure has been removed, and
• Stand away from the valve when removing the Gland and Cover.
A number of procedures in this manual may cause flying debris that may cause eye injuries. Safety
glasses should be worn at all times while repairing and maintaining Dynamic Balance valves.
The procedures described in this manual are intended only for Dynamic Balance Plug Valves. Do not
follow these procedures for any other brand or type of valve.
Basic Construction Principles
So that you may develop a plan of proper maintenance, it is best to understand the basic principles
involved in Dynamic Balance iron plug valves.
The lubricated plug valve was invented by Sven Nordstrom in 1914, and basically represented an
application of Pascal’s Law of Hydraulics to the dry plug cock. Mr. Nordstrom created a valve sealant
system to prevent taper lock in plug valves and enable the valve closure member to be operated easily.
Over the years, as valve services became more severe and as technology improved, several design