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

- 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 and 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/oil carried along is also discharged via the bypass. The aligned incoming flow of the diaphragm has another additional self-cleaning effect. An alarm is indicated via the upstream variable area flowmeter with monitoring (refer to sample applications).

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


Schematic representation:


Technical specifications:

Scope of delivery: Housing complete with membrane, filter and, 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
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
Housing dimensions: Diameter 60 mm, height 30 mm, with assembly bracket 100 mm
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   -10°C ≤ Ta ≤ +80°C attestation EPS 19 ATEX 2 178 U
Dust explosion proof ATEX: EX II 2D Ex h IIC Gb   -10°C ≤ Ta ≤ +80°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

Order numbers:

protection of utility patents DE 20 2016 100 476

Item 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) green OR305FKM
Set of O-rings PTFE white OR305PTFE
Set of O-rings FFKM black OR305FFKM
Supporting sieve STUESI305
Spare parts kit 1, including:
1 x MEM305, 1 x OR305FKM, 1 x STUESI305


Note: The standard product is equipped with FKM O-rings.

Sample application for flue gas analysis with bypass:

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