Industrial Strainers & Screens

How to Select a Strainer

Four parameters decide the model, and they are interdependent — a change in one usually moves the others. Quoting a strainer without all four produces a unit that fits the pipe but not the duty.

Line size and connection standard

Nominal bore plus the flange standard — ASME B16.5, EN 1092-1 or JIS. A strainer drilled to the wrong standard cannot be installed regardless of its pressure rating.

Pressure class and design code

The rating has to cover the design pressure, not the operating pressure. Specify whether the vessel is designed to ASME VIII or PED, because the calculation and the documentation differ.

Mesh or perforation size

Set by the smallest particle the downstream equipment can tolerate, not by habit. An oversized basket passes the debris it was bought to stop; an undersized one blinds and costs pressure drop.

Body and trim material

Carbon steel, 304 or 316L, duplex, or an exotic alloy. The fluid, not the budget, should decide — and the gasket and screen material have to be named separately.

Documentation Supplied With Every Unit

For a pressure-retaining item the paperwork is part of the product. These are issued against the serial number on the nameplate, not against the catalogue entry.

• Material certificates. EN 10204 3.1 mill certificates for the body and the screen, traceable to the heat number.
• Pressure test record. Hydrostatic or pneumatic test at 1.5× design pressure, with the hold time and the result recorded.
• Dimensional and NDE reports. Weld maps with the NDE method and acceptance criteria where the code requires it.
• Installation and maintenance data. Flow direction, basket removal clearance and the torque figures for the cover bolts.