Dirt Loading
The percent by weight of particulate contaminant in the liquid stream to be filtered, or the particulate matter, in slurry form, from which the moisture is to be removed.

Flow Rate
The volume of liquid, measured in gallons per minute (GPM), to be filtered.

Viscosity
The inherent resistance to flow of the liquid to be filtered, measured in centipoise.The more viscous a fluid, the less easily it will flow. The lower the viscosity, the faster the fluid will flow.

Particle Size
The mean diameter of the smallest particles to be removed measured in microns or standard US mesh sizes.This should also include the type of particulate (hard, gelatinous) encountered.

Service Temperature
This should include both the service and design temperatures. It is also important to determine the viscosity of a fluid at its operating temperature. (Liquid viscosity generally decreases as the temperature increases.) If the fluid is extremely viscous, it is advisable to preheat the fluid and install a heating jacket on the strainer housing.

Service Pressure
This should include both the service and design pressure.

Differential Pressure Drop
Resistance to flow through a clean strainer is the sum of the resistance due to the strainer medium, strainer hardware, and the strainer housing. For a fluid of a given viscosity, the smaller the diameter of the pores/slots within the straining medium, the greater the resistance to flow, that is pressure drop.

Life Cycle Cost
The capital and operating costs spread over the expected life of the unit.One may lean towards buying a strainer because of its low initial cost.However, other features such as frequency of basket cleaning and replacement, and associated labor, disposal and production downtime costs will need to be considered and should impact the final selection.

Lower Maintenance Costs
These also vary widely. It is important to know how relatively high or low they are for each type of straining system.

Limited Downtime
Certain straining systems by their nature, require significantly more downtime in their operation,while others have been designed to minimize downtime. Whether your operation or batch is continuous is another selection factor.

Compatibility
It is also essential to determine if the fluid is acid, alkali, aqueous, oil or solvent based, and if it has additives present that affect compatibility. The chemical composition and the thermal range of the liquids you wish to strain will determine what metals and media are suitable for use. All materials that come in contact with the process fluid at operating temperature (baskets, screens, hardware, housing material, gasketing),must be compatible with the fluid.