Water-Oil-Trap with extra fine particle filter

model WT 30.5 E in a stainless steel housing

- With Dual-Membrane-System® to stop of water, acid, alkali, liquid hydrocarbons and extra fine dust

- Bypass integrated

- Minimum gas volume of just 2 ml

- Especially für gas-chromatographsn

- “Easy Change System” of the inner diaphragm After removing the cover screws, the diaphragm can be replaced quickly and effortlessly. It is not necessary to remove the screw connections

-All gas connections on the lower part of the housing

- Made in Germany  

- Certificates: 3.1 material quality certificate, ATEX 2014/34/EU, Helium leakage tested







Functional description:

The Water-Oil-Trap is used as a protection of gas analysers from liquids (Water, acid, alkali, liquid hydrocarbons)and particles. A bypass connection is integrated.

The Water-Oil-Trap is installed directly in front of the gas analyser in the tubing. If the upstream gas processing (cooler, peristaltic pump, dust filter and the like) fails, the Water-Oil-Trap uses its semi-permeable membrane with SUN-C Dual Membrane System® to protect the gas analyser. The membrane separates gases from condensate and extra fine dust. The Water-Oil-Trap is designed as a bypass filter. The main gas flow can be discharged again via the bypass; a partial current (1:2 to 1:20) will be provided to the analyser. This results in quick response times of the analyser. Condensate carried along is also discharged via the bypass. The aligned incoming flow of the membrane has another additional self-cleaning effect. An alarm is indicated via the upstream variable area flowmeter with monitoring (customer side).

The Water-Oil-Trap is also known as a “Police filter”.


Schematic representation:


Technical specifications:

Scope of delivery: Housing complete with membrane, filter and, wall assembly bracket
Water pressure membrane: 0 - 2,0 bar with DMS (Dual-Membrane-System®)
Oil pressure (10W40) membrane: 0 – 0,3 bar with DMS (Dual-Membrane-System®­)
Gasoline (ROZ 95) Membrane: 0 – 0,2 bar with DMS (Dual-Membrane-System®)
The Dual-Membrane-System® of the Water-Oil-Traps is a novel membrane system. Condensates such as water, acid, alkali and liquid hydrocarbons, for example, oils and gasolines in refinery process gases are retained.
The design is subject to a legal protection of registered designs (registered number 20 2016 100 476)
Operating pressure for gas: 0 - 50 bar (higher pressures on request)
Gas flow: 0 - 60 l air/h
Pressure drop at 15 l air/h: approx. 30 mbar
Pressure drop at 30 l air/h: approx. 60 mbar
Pressure drop at 60 l air/h: approx. 130 mbar
Diaphragm pore size: < 0,1μm
Operating temperature: - 20°C - +190°C
Effective filter area: 12 cm2
Housing volume: 2 ml
Materials used: Stainless steel type 1.4571, FKM (Viton), PTFE
Wall mounting bracket (option): Stainless steel type 1.4301
Housing dimensions: Diameter 60 mm, height 60 mm, Depth 100 mm (incl. mounting bracket)
Gas connections: GAS-IN 1/8“ NPT inside thread
BYPASS 1/8“ NPT inside thread
GAS-OUT 1/8“ NPT inside thread
Assembly: Wall mounting with assembly bracket (included in scope of delivery)
Assembly advice: Installation of the bypass is recommended. Consider the max.membrane pressures if no bypass is possible
Gas explosion proof ATEX: EX II 2G Ex h IIC Gb   -20°C ≤ Ta ≤ +190°C attestation EPS 19 ATEX 2 178 U
Dust explosion proof ATEX: EX II 2D Ex h IIC Gb   -20°C ≤ Ta ≤ +190°C attestation EPS 19 ATEX 2 178 U
Helium leakage test: 2 x 10-7 mbar I/s
Language operating instructions: German and English (included in the scope of delivery)
  Spanish, Italian, French, Russian upon request
Certificates/attestations: 3.1 material quality certificate, NACE-MR0175-98, ATEX 2014/34/EU, Helium leakage test attestation


For operation in potentially explosive ambience:

The products can be used in explosive ambience of Zone 1, Zone 2, Zone 21 und 22.
Allowed the explosion classes IIA, IIB und IIC.
The products have no self-heating during intended operation and can be used in dependency of the maximum
permissible media temperature for gases of the temperature class T6.

Helium leakage test:

The product line has been subjected to a helium leak test. Single attestation on request


Oil and grease-free products for applications with 100% oxygen (on request)

protection of utility patents DE 20 2016 100 476

Article numbers:

Article Item number
Water-Oil-Trap WT 30.5 E Material stainless steel 1.4571 (316 Ti), as per technical specifications. O-rings FKM (standard) WT305E
Water-Oil-Trap WT 30.5 E Material stainless steel 1.4571 (316 Ti), as per technical specifications. O-rings PTFE WT305EORPTFE
Water-Oil-Trap WT 30.5 E Material stainless steel 1.4571 (316 Ti), as per technical specifications. O-rings FFKM WT305EORFFKM
1 unit of assembly adapter for front panel assembly, Material plastic (PTFE) ADAPFROP305

Spare parts:

Spare membrane, including white membrane, grey membrane and indicator plate MEM305
Set of O-rings FKM Viton (standard) color green OR305FKM
Set of O-rings PTFE, color white OR305PTFE
Set of O-rings FFKM, color black OR305FFKM
Supporting sieve STUESI305
Spare parts kit 1, including:
1 x MEM305, 1 x OR305FKM, 1 x STUESI305


-The standard product is equipped with FKM O-rings. For additional information about O-rings, refer to “Informations”.
-PTFE O-rings for single use only

Sample application for flue gas analysis with bypass:

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