Oil mist separation efficiency test bench

The Oil Mist Separation Efficiency Test Bench is a modular, high-performance testing system designed for precise evaluation of oil separators, coalescing filters, inertial separators, and electrostatic filtration systems. It enables reliable characterization of separation efficiency, loading and holding time, pressure loss, and fractional efficiency under real operating conditions.

Equipped with a heated light-scattering spectrometer, heated dilution system, and heated aerosol generator, the test bench supports isothermal measurements up to 120°C, ensuring stable, reproducible, and internationally comparable results.

Application

The system is suitable for a wide range of industrial, automotive, and laboratory applications, including:

Quality assurance of oil separators

Development of coalescing, cyclone, and inertial separation units

Evaluation of separator performance for:

– Leaked aerosols in combustion engines

– Oil mist downstream of compressors

– Machine tool cooling lubricants

– Minimum-quantity lubrication aerosols

In-situ particle sampling and field testing on engines

Research on oil mist behavior under varying temperature and flow conditions

Standards

This system is designed with reference to relevant international and Chinese standards, including:

GB/T 6165-2021 – Test method for high-efficiency air filters

General guidelines for aerosol separation and fractional efficiency measurement

Commonly used international particle measurement practices

Features

Modular construction, allowing components to be removed and used independently

Isothermal and isobaric measurement up to 120°C

High-resolution light scattering spectrometer for simultaneous particle size and number measurement

Fast, reproducible, and operator-independent measurements

Heated aerosol generation, dilution, sampling, and measurement pathways

Automatic system control with FTControl software

Automatic measurement of fractional efficiency and pressure-loss curves

High reproducibility and internationally comparable results

Easy to operate; minimal training required

Low maintenance costs and short setup time

Customer-initiated cleaning and calibration

Mobile platform for flexible field use

Technical parameters

Advantages

Grading and Separation Efficiency and Feed Measurement and Evaluation

Isothermal and Isobaric Measurements

All Components Can Be Heated to 120°C

High Reproducibility of Test Methods

Internationally Comparable Measurement Results Due to the Widely Used Measurement System

Customer-Initiated Cleaning and Calibration

Easy to Operate; Even Untrained Personnel Can Quickly Use the Equipment

Modular Layout Offers Greater Flexibility

Validate the Functionality of Individual Components and the Entire System During Pre-Delivery Acceptance Testing and Upon Delivery**

Reliable Operation

Short Setup Time and Extremely Low Maintenance Costs

The Equipment Will Reduce Your Operating Costs

Figure 1: Advantages of Optical Particle Measurement over Pure Gravimetric Analysis:

Traditional quantitative gravimetric analysis is often not fast or sensitive enough and cannot provide information about particle size distribution. Due to the excellent correlation between quantitative distribution measurement and gravimetric analysis, very rapid and volume-dependent testing of oil separators can be ensured. The concentration of clean gas can be determined in 1 minute using the system.

Why Use Isothermal Measurement?

The viscosity of oil – and therefore the size and concentration of particles in the oil mist – varies as a function of engine temperature. Therefore, oil separators must be tested at different temperatures, for example, with different particle sizes (up to approximately 5-8 µm) and particle concentrations (approximately 10⁵-10⁷ particles/cm³), as well as different volumetric flow rates, in order to clearly characterize their separation capabilities. Variations in separator separation characteristics, such as due to changes in volumetric flow rate, temperature, filter load, etc., must be clearly determined through reliable online or field measurements. To avoid condensation and the effects of evaporation on the HMT 1000. the entire aerosol conduit (including the preparation, sampling, and measurement volumes) can be heated to 120°C. This allows for isothermal measurements of fractionation efficiency. Isothermal in-situ measurements, such as on an engine, are also possible.

The HMT 1000 testing system is mobile and features a modular layout. Therefore, individual components can also be used for other tests and particle measurements, such as in-situ measurements on an engine.

Figure 2: Isothermal particle sampling and field measurement using FTControl software for automated measurement data acquisition.

The software has been tested and validated with particles and enables fully automated characterization of oil mist separators. This means results are independent of the operator of the test bench (see the "Software" product group: FTControl). Test Bench Control:

• Automatic control of volumetric flow rate

• Automatic activation of the aerosol generator

• Automatic switching between feed gas/clean gas measurement points

• Automatic temperature control

• Evaluation and recording of measurement signals such as Dp, relative humidity, temperature, volumetric flow rate, absolute pressure, etc.

Automatic Measurement Process:

• Automatic evaluation of pressure loss curves

• Automatic measurement of fractionation efficiency

• Automatic evaluation of pressure loss curves under different feed conditions, including fractionation efficiency measurement

Figure 3: Comparison of Different Oil Separators

Test Procedures

System Preparation

Heat the aerosol conduit, dilution system, spectrometer, and generator to the required test temperature (up to 120°C).

Aerosol Generation

Activate the heated aerosol generator and allow it to reach stable concentration.

Flow Setting

Automatically set the volumetric flow according to test requirements.

Measurement Sequence

• Automatic switching between feed gas and clean gas measurement points

• Real-time acquisition of particle size distribution and concentration

• Measurement of pressure loss and fractional efficiency

Data Analysis

FTControl software automatically evaluates:

– Fractional separation efficiency

– Pressure-loss curves

– System temperature, humidity, and pressure data

– Loading and holding performance

Reporting

Test bench generates complete data sets and graphical outputs for quality control or R&D documentation.

Maintenance Information

Clean and inspect the aerosol generator and sampling lines regularly to avoid oil accumulation.

Perform calibration of sensors and spectrometer according to manufacturer guidelines.

Check heating components, seals, and insulation to ensure stable isothermal operation.

Inspect flow controllers, pressure sensors, and valves periodically for wear.

Keep the software updated and back up measurement data routinely.

Ensure compressed air supply is dry and clean to protect internal components.

Before long-term shutdown, remove residual oil and purge the system.