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Caution for Selection  
How to Specify and Order the Correct Valves
This is to assist you in choosing the correct valve for a vast number of piping conditions. The Welco product line makes available to you a very broad choice of valves. These valves are described in this website.
Care should be taken to select the most suitable valves for your service(s). Exact specification of each valve should be made to avoid possible ambiguity. When requesting quotations and/or ordering the product a fully adequate description should be made.
Selecting the Valve Size
Nominal size of the pipeline into which the valve will be placed must be determined.
Valve Material
The following factors should be considered in determining the correct valve material:

  • the medium or media which will be controlled
  • the temperature range of the line medium (media)
  • the pressure range to which the valve will be subjected
  • possible atmospheric conditions which may affect the valve
  • possible extraordinary stresses to which the valve will be subjected
  • safety standards and/or piping codes which must be met
  • Type of Valve
    What is the control function of the valve? Each valve configuration has been developed to perform certain control functions. Do not expect one type of valve to perform all the valving jobs in a system.
    Pressure-Temperature Ratings
    Please pay careful attention that the pressure-temperature ratings of a particular valve are in keeping with the requirements of the service. Pay especially careful attention to the packing and gasket materials as this may limit the rating as is the case with PTFE used as the standard in weIco valves. Specify alternative packing and/or gasket materials as necessary to meet or exceed your service requirements.
    Valve and Connections
    Considerations as to pipeline integrity, future maintenance, corrosion factors, field assembly, weight and safety should be given in determining the method of connecting the valve in the pipeline.
    Method of Operation
    The means by which the valve is operated as supplied are shown for the valves in this website. Many optional operating devices are regularly supplied by welco.

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