Filter and strainer symbols
Filters, strainers and cyclones remove solids or liquids from a stream. They are drawn in the line, usually upstream of the equipment they protect, such as a pump or a control valve.
- FilterA filter removes particles from a liquid or gas with a filter element.
- Y-strainerA Y-strainer catches debris in a mesh screen held in a branch set at an angle to the line.
- Basket strainerA basket strainer holds a removable mesh basket in a pot below the line.
- CycloneA cyclone separates solids or droplets from a gas or liquid by spinning the flow, which throws the heavier material to the wall and down to the outlet.
Filters and strainers in ISO 10628-2
About ISO 10628-2Filters often carry a tag starting with F or S. A differential pressure gauge or transmitter across a filter (PDI or PDT) shows when it needs cleaning.
The cards at the top use the forms of US legend sheets (PIP PIC001 practice). The grids below them show the same symbols as ISO 10628-2 or IEC 62424 draw them. See ISA vs ISO P&ID symbols for the differences.
Frequently asked questions
What are filter and strainer symbols on a P&ID?
Filters, strainers and cyclones remove solids or liquids from a stream. They are drawn in the line, usually upstream of the equipment they protect, such as a pump or a control valve.
How many filter and strainer symbols are there?
This legend covers the 4 most common ones: filter, Y-strainer, basket strainer, cyclone. Project legends may add company-specific variants.
Can I download these symbols?
Yes. Each symbol page has a free SVG and PNG, and the whole legend is available as a printable PDF chart on the P&ID symbols page.