Hydraulic oil purification and filtration tester

Hydraulic oil purification and filtration testers are essential tools for characterizing the performance of fluid cleaning technologies. A common type of tester, particularly for evaluating filter elements, utilizes the multi-pass test principle (standardized by ISO 16889). In this method, contaminated hydraulic oil is continuously circulated from a reservoir, passed through the filter element under test, and returned to the reservoir. As the test progresses, solid particles are continuously injected into the reservoir, and fluid samples are taken from both upstream and downstream of the filter. An automatic particle counter analyzes these samples to determine the number and size distribution of particles. By comparing the upstream and downstream particle counts at different sizes, the filter's Beta ratio (a measure of efficiency) and dirt holding capacity (the amount of contaminant a filter can retain before reaching a specified differential pressure) are determined.

For evaluating purification systems (such as those for removing water or dissolved gases), testers may involve circulating oil through the purification unit and measuring the contaminant levels (water content via Karl Fischer titration or sensors, dissolved gases via gas chromatography or sensors) before and after the process. These testers provide crucial data for selecting appropriate filtration and purification solutions, monitoring their performance, and ensuring that hydraulic fluids meet required cleanliness standards (e.g., as specified by ISO 4406 cleanliness codes).

Applications

Suitable for hydraulic and lubrication systems in industries such as power generation, steel, shipbuilding, chemical, mining, and construction machinery, and ideal for various industrial customers requiring efficient oil purification.

Standards

ISO 16889:2022：Hydraulic fluid power — Filters — Multi-pass method for evaluating filtration performance of a filter element

ISO 4406:2021：Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles

ASTM D7619-22：Standard Test Method for Sizing and Counting Particles in Light and Middle Distillate Fuels, by Automatic Particle Counter

ISO 11500:2022：Hydraulic fluid power — Determination of the particulate contamination level of a liquid sample by automatic particle counting using the light-extinction principle

Features

Provides objective, quantitative data on filter performance (Beta ratio, dirt holding capacity).

Evaluates the effectiveness of purification methods in removing water and gases.

Essential for maintaining desired hydraulic fluid cleanliness levels.

Standard compliant test methods, particularly the widely recognized ISO 16889 for filter performance.

Helps predict the lifespan and effectiveness of filters and purification systems in real-world applications.

Crucial for ensuring the reliability and longevity of hydraulic components and systems by controlling contamination.

Facilitates informed decision-making in selecting appropriate fluid cleaning technologies.

Supports quality control and research and development efforts in fluid power and filtration industries.

Technical Parameters

Accessoriess

1. Particle Counter. Directly displays NAS 1638 or ISO 4406 ratings, allowing customers to easily assess oil usage online;

2. Temperature Sensor. Displays system oil temperature in real-time online;

3. Ultra-High Efficiency Filter. Ultra-high efficiency filters offer higher filtration efficiency and longer service life than ordinary filters.

Test Procedures

1. Preparation Stage

Equipment & Sample Setup

Connect the tester to a stable power supply, and ensure the hydraulic oil reservoir is filled with the target test oil (match the hydraulic system’s oil type).

Install the filter element to be tested into the designated position of the tester, and check the tightness of the pipeline connections.

Prepare contamination particles (conforming to ISO 16889 requirements) for injection into the oil circuit.

Parameter Configuration

Turn on the instrument, select the test standard (e.g., ISO 16889) via the control panel.

Set test parameters:

Oil flow rate (simulate actual hydraulic system flow);

Target contamination level (reference ISO 4406);

Differential pressure threshold (for determining the filter’s dirt holding capacity).

2. Multi-Pass Filtration Performance Test (for Filter Elements)

Circulation & Contamination Injection

Start the oil circulation system, and continuously inject solid particles into the reservoir to maintain the set contamination level.

Let the oil pass through the test filter element and return to the reservoir (forming a closed loop).

Particle Counting & Data Collection

Use the built-in automatic particle counter (compatible with ISO 11500) to take upstream and downstream oil samples at set intervals.

Record data: particle size distribution, count, and system differential pressure.

Performance Calculation

Calculate the filter’s Beta ratio (efficiency) by comparing upstream/downstream particle counts.

Continue the test until the differential pressure reaches the set threshold, then record the dirt holding capacity (total contaminants retained).

3. Purification System Performance Test (for Water/Gas Removal)

Water/Gas Injection

Inject water (or dissolved gas) into the test oil to reach the initial content (monitor via Karl Fischer sensor or gas chromatography).

Purification Process

Start the purification system (e.g., dehydration module), and circulate the oil through the system.

Content Monitoring

Test the oil’s water/gas content before and after purification (reference ASTM D7619 for fuel-related particle testing, if applicable), and record the removal efficiency.

4. Post-Test Process

Stop the circulation system, drain the test oil, and clean the reservoir/pipelines.

Remove the test filter element, and clean the instrument components.

Export the test data (Beta ratio, dirt holding capacity, purification efficiency) and generate a report.