Selection of Mesh Size for Y-Type Strainer Screens & Engineering Recommendations for Different Working Conditions
Y-type strainers are common and vital protective fittings in industrial piping systems including water supply and drainage, steam, oil & gas, and circulating water systems. They are normally installed upstream of equipment and instruments such as pressure reducing valves, flow meters, transfer pumps and regulating valves to intercept impurities like rust, welding slag and sediment, so as to avoid clogging, abrasion or malfunction of downstream equipment.
Core Logic for Model Selection
Many people struggle most with one question during selection: what mesh size should be chosen for the filter screen? The core principle of Y-type strainer selection is to strike a balance between filtration precision and operating pressure drop. A properly selected strainer achieves equilibrium between filtering accuracy and flow capacity. Excessively high mesh numbers lead to frequent clogging and elevated pressure differential, raising maintenance costs. Conversely, overly low mesh sizes fail to trap contaminants effectively, resulting in inadequate equipment protection.
The following is a detailed selection guide formulated based on chemical industry standards and engineering experience：
Model Selection by Different Working Conditions
- Water Supply, Drainage and Industrial Circulating Water Systems
Generally, 20 to 40 mesh is selected. Working conditions of this type mainly intercept silt, biological slime and other contaminants, with greater emphasis on flow capacity and stable operation; an excessively high mesh number will instead lead to frequent clogging.
- Steam Systems
40 to 80 mesh is normally selected. It can effectively filter fine impurities such as scale and welding slag to protect equipment including pressure reducing valves.
- Fuel oil, gas, lubricating oil, etc.
60 to 100 mesh is generally adopted. Oil and gas equipment are more sensitive to contaminants, requiring higher filtration precision.
- Instrument Air & Precision Equipment
Mesh sizes above 100 mesh are mostly adopted. Used as pre-filtration matched with precision filters at the downstream side, it delivers finer filtration performance. Regular cleaning is required to prevent clogging from disrupting system operation.
- Fuel oils, gas, lubricating oils, etc.
40 mesh is adopted by default for pump and valve protection if there are no special requirements. If the medium is relatively clean, 20 mesh can be selected to reduce flow resistance.
How to Determine Whether the Strainer Needs Cleaning
- Refer to equipment manuals: First confirm the particulate requirement (μm) of downstream precision equipment (e.g., mass flow meters, metering pumps), and derive the required mesh size accordingly.
- Viscosity verification: For high-viscosity media (μ > 100 cP), the pressure drop may multiply with every 20-mesh increase; initial pressure drop calculation shall be performed when necessary.
- Material matching: 304SS or 316SS is commonly adopted as strainer screen material for chemical service. 316L or special alloys shall be considered for chloride-containing or strongly acidic media to prevent screen corrosion and rupture.
- Area margin: The effective filtering area of the Y-type strainer shall be 3 to 4 times larger than the cross-sectional area of the pipeline to reduce flow velocity and clogging risk.
