Flow Rate vs. Pressure Drop Testing

As the name implies, the flow rate vs. pressure drop test measures the oil flow resistance (pressure drop) as oil passes through the filter.

[Test Circuit]

By utilizing the above test circuit configuration, we compare the pressure rating as liquid enters the test filter (P1) and again when it exits the filter (P2). Through this testing we are able to determine the drop in pressure: (△P=P1-P2).

Element Flow Rate vs. Pressure Drop Test Results

[Establishment of Test Flow Rate]
When determining the flow rate to be used for testing a given filter, we basically test the sample from 0 liters per minute to at least 1.2 times the filter’s specified flow rate specification determined by the filter’s application within the hydraulic circuit.

Particularly, in the case of return filter elements, flow rate requirements can be nearly twice those of a filter situated near the hydraulic pump. Therefore, it is important to consider the application of any filter before determining the test flow rate to be used.

Element Flow Rate vs. Pressure Drop Test Results

[Filter Housing Assembly Testing]
When testing a filter housing assembly, we test both the housing by itself (without filter element) and the housing with the element installed. By subtracting the pressure drop rating of the filter housing from the pressure drop rating of the housing with the element installed, we can determine the pressure drop for the element.

Yamashin Filter Manufacturing Corporation
Hydraulic Filter Group