In cooperation with Ehrler Prüftechnik Engineering, Palas^® has designed a unique test rig for compressed air filters which makes use of the energy-efficient circulation concept for the Institute of Energy and Environmental Technology (IUTA) in Duisburg, making testing of filters at a volume flow rate of 3,000 m³/h and an absolute pressure of 8 bar possible.

Large-scale compressed air filters are used in many sectors, including hospitals, the automotive, food, and pharmaceutical industries, paint shops, and the electrical industry. Before that, the IUTA could only test smaller filters with up to 50 m³/h volume flow rates. Conclusions by analogy had to be used to deduce the performance of large filters with volume flow rates up to 60 times greater than that. The new test rig allowed the institute to precisely measure these filters’ performance.

The circulation concept increases energy efficiency

The circulation concept is a significant feature of the test rig. The circulation is pumped up to 8 bar and uses other inline blower fans to ensure the pre-compressed air is fed into the circular flow. This dramatically reduces energy requirements. The test rig uses thewelas ^® digital 1000 P aerosol spectrometer and the aerosol generators PLG 3000 for the fractional separation efficiency and AGF 3000 for the charge concentration. The aerosol generators charge the compressed air filters with droplets of compressor oil, thus simulating the contamination of the compressed air. The welas ^® digital 1000 P determines the filters’ fractional separation efficiency. This enables the measurement directly at 8 bar absolute. This also makes it possible to measure relatively high particle concentrations.

The software automatically calculates the fractional separation efficiency and indicates factors such as particle size distribution and mass concentrations, which can be calculated based on. The long-term data storage function is also essential for tests lasting 70 to 80 hours.

Complex airlock system

The test rig allows gravimetric determinations to be conducted simultaneously with the particle measurement. To accomplish this, Palas® built and supplied a complex and complicated airlock system. It is used to emit a partial current to an absolute filter automatically. This absolute filter can be removed for analysis without completely shutting down the test rig.

Our solution for you: DFP 3000

Based on the insights gained from the joint project, Palas^®went on to develop the DFP 3000.

The DFP 3000 also delivers fully-automated measurements of fraction separation efficiency for compressed air filters under overpressure up to 7 bar, offering better results than ISO 12500. The fraction separation efficiency is measured with the aerosol spectrometer Promo ^® 3000 P.

The DFP 3000 can be equipped with three different aerosol generators:

• For measurement of the fraction separation efficiency with oil: PLG 3000
• For burden tests, short burdening times with oil: AGF 3000
• For tests with solid particles up to 3 bar: RBG 1000 D

The DFP 3000 offers a precise determination of the particle size and concentration directly under overpressure up to 10 bar, as well as an automatic adjustment of the sampling volume flow in the event of pressure changes. All air volume flows, and the overpressure in the system are automatically monitored and adjusted. The results are presented in detailed form in tables and diagrams and analyzed.
Test rigs by Palas^®enable internationally comparable measurement results and high reproducibility of the testing method.