Filter Assembly Sizing Guidelines

Effective filter sizing requires consideration of flow rate, viscosity (operating and cold start), fluid type and degree of filtration. When properly sized, bypass during cold start can be avoided/minimized and optimum element efficiency and life achieved. The filter assembly differential pressure values provided for sizing differ for each media code, and assume 32 cSt (150 SUS) viscosity and 0.86 fluid specific gravity. Use the following steps to calculate clean element assembly pressure drop.

Sizing recommendations to optimize performance and permit future flexibility

• To avoid or minimize bypass during cold start the actualassembly clean ΔP calculation should be repeatedfor start-up conditions if cold starts are frequent.
• Actual assembly clean ΔP should not exceed 10% of bypassΔP gauge/indicator set point at normal operating viscosity.
• If suitable assembly size is approaching the upper limitof the recommended flow rate at the desired degreeof filtration consider increasing the assembly to thenext larger size if a finer degree of filtration mightbe preferred in the future. This practice allows thefuture flexibility to enhance fluid cleanliness withoutcompromising clean ΔP or filter element life.
• Once a suitable filter assembly size is determined considerincreasing the assembly to the next larger size to optimizefilter element life and avoid bypass during cold start.
• When using water glycol or other specified synthetics, werecommend increasing the filter assembly by 1~2 sizes.