Filter Flow Resistance Tester

The Filter Flow Resistance Tester operates by circulating a test fluid (such as hydraulic oil, lubrication oil, fuel, water, or air, depending on the filter's intended application) through the filter element or complete filter assembly under test. A variable speed pump or flow control valve is used to establish and control a range of flow rates through the filter. Pressure sensors or transducers are strategically placed immediately upstream and downstream of the filter to measure the pressure on both sides. The difference between these two pressure readings is the pressure drop across the filter at that specific flow rate. The tester systematically measures the pressure drop at multiple flow rates across the filter's operating range.

Applications

Determining the clean filter pressure drop versus flow rate characteristics of filter elements and assemblies.

Comparing the flow resistance of different filter designs, media, and manufacturers.

Selecting filters based on acceptable pressure drop limits for a given system flow rate.

Validating filter specifications provided by manufacturers.

Optimizing hydraulic or lubrication system design to minimize energy losses due to filtration.

Quality control during filter production to ensure consistent flow characteristics.

Research and development of new filter media and designs with lower flow resistance.

Standards

ISO 3968:2009：Hydraulic fluid power — Filters — Determination of pressure drop versus flow rate characteristics

SAE J806:2019：Filter Elements, Hydraulic, for Mobile Equipment

Features

Based on typical Filter Flow Resistance Testers:

Test fluid reservoir.

Variable flow rate pump or flow control system capable of generating and maintaining stable flow rates through the filter over a specified range.

Filter housing or fixture designed to securely hold the filter element or complete filter assembly under test, with connections for upstream and downstream pressure measurement.

Pressure transducers or sensors located upstream and downstream of the filter to measure pressures.

Differential pressure transducer (often included) to directly measure the pressure drop across the filter.

Flow meter to accurately measure the test fluid flow rate.

Temperature control system for the test fluid to ensure testing is performed at a consistent and relevant temperature, as viscosity affects pressure drop.

Technical Parameters

Accessoriess

1. Core Test Accessories

Filter clamps compatible with different specifications: Used to fix filter elements/complete filter assemblies, ensuring a leak-free seal during testing.

Pressure sensors/transmitters: Installed in pairs upstream and downstream of the filter to accurately measure pressure values on both sides.

Variable speed pumps/flow control valves: Adjust and control the flow range through the filter to match test requirements.

2. Functional Auxiliary Accessories

Test fluid containers: Store test media such as hydraulic oil and lubricating oil, adaptable to different filter application scenarios.

Flow monitoring module: Synchronously records the real-time flow through the filter and generates characteristic curves in conjunction with pressure data.

Control system host: Integrates an operating interface for setting flow parameters and acquiring/analyzing pressure-flow data.

3. Consumables and Auxiliary Components

Sealing components (e.g., O-rings): Ensure the sealing effect between the clamps, filter, and pipeline, preventing media leakage from affecting test accuracy.

Compatible pipelines: Transmit test fluids; materials must be compatible with different types of test media (oil, water, air, etc.).

Test Procedures

1. Preparation Stage

Equipment and Sample Installation: Secure the filter under test (filter element/assembly) in the dedicated fixture, connect the upstream and downstream pipelines, and ensure a seal; add the corresponding medium (e.g., hydraulic oil) to the test fluid container.

Component Inspection: Confirm that the pressure sensor, variable speed pump, flow valve, and other components are properly connected, and initiate the equipment self-test.

2. Parameter Setting

Select the test standard (e.g., ISO 3968) through the control system host, and set the target flow range (covering the filter's operating range).

Set the data acquisition interval (pressure drop needs to be measured at multiple flow points).

3. Test Operation

Start the variable speed pump and gradually adjust the flow rate through the filter according to the set flow gradient.

The pressure sensor collects the pressure values upstream and downstream of the filter in real time. The system automatically calculates the pressure drop (pressure difference between upstream and downstream) and records the corresponding flow rate simultaneously.

Complete the pressure drop measurement at all set flow points sequentially, generating a "pressure drop - flow rate" characteristic curve.

4. Post-processing Stage

Stop the equipment, drain the test medium, disassemble the filter under test, and clean the fixture and pipelines.

Export test data, analyze the pressure drop characteristics of the filter, and complete the test report (which can be used to compare different filters or verify manufacturer specifications).