Installation Considerations

For protection of pipeline equipment under relatively clean service conditions where there is little debris loading for both vapor (natural gas, air, steam etc.) and liquid service, a y-strainer is generally the strainer of choice.  In liquid service applications however, where the debris loading is higher and collection of solids is required, basket strainers should be considered.  This is because basket strainers, both simplex and duplex, have more gross strainer basket area than a y-strainer has gross screen area, and the ratio of free area to pipe area for basket strainers is greater than for a similar size y-strainer.

Y-strainers can be installed in either a horizontal or vertical pipeline, whereas basket type strainer are designed for installation in horizontal lines.  The flow must always be into the inlet – into the screen or basket (s) – for satisfactory operation.  If y-strainers are installed in a vertical line, the flow must be from top to bottom (downward).  The blow down (drain) may be angled 45 degrees maximum.

The following items should all be considered in selecting the proper strainer of an application:

• The material of construction.
• The design and working pressures.
• The design and working temperatures.
• The service (liquid or vapor).
• The flow rate and viscosity (if a liquid).
• The particle size to be retained.
• The debris loading.
• The seal material (o-ring or gasket).
• Whether the line flow can be interrupted or not for basket/screen cleaning.
• The clean start up pressure.
• The location of the strainer.

Cast iron and carbon steel construction basket strainers are generally acceptable for fresh/city water, and lube oil services.  Bronze and stainless steel are generally acceptable for brackish/salt water use.  Carbon steel is generally acceptable for straining fuel oils.  Stainless steel is generally acceptable for most chemical applications.

Y-strainers constructed of cast iron, bronze, carbon and stainless steel are generally acceptable for steam, air, natural gas or liquids.

Don’t overstrain, the opening in the basket or screen should never be smaller than one-half the size of the largest particle whose presence in the system is considered harmful.