
The static filter unit for low dust loading up to 5 mg/m³.

The static filter system
HETstatic is the supply air or exhaust air filtration system for clean rooms. The system can be designed in any number of filter stages to clean the air in several steps. Technologies such as SafeChange and Wash-in-Place (WIP) allow the filter cells to be changed safely and enable containment up to level OEB 5. Thanks to their robust design, the modules are suitable for use in almost all areas.
HETstatic
Advantages
- HEPA HEPA filtration for the highest purity in the air
- Safe containment up to OEB 5
- Suitable for low dust concentrations < 5 mg/m³
- Plant in dust-tight or gas-tight design
- Conductive equipment
- Safe-change system for filter change
- Small size
- Use as a duct filter
- Especially Robust due to high sheet thickness
Features

Filter housing
The welded filter housing is made of S235JR and powder coated in RAL 7035.
The bolted filter housing is made of S235JR and powder coated in RAL 7035. The welded filter housing is made of stainless steel 1.4301 (AISI 304). The welded filter housing is made of stainless steel 1.4404 (AISI 316). The welded filter housing is made of stainless steel 1.4571 (AISI 316Ti). All welds are pickled and passivated.
To obtain a uniform surface appearance, the filter housing is glass bead blasted. The filter housing is completely ground. (The micrograph has a vertical / horizontal arrangement. All weld seams are, if possible, ground to a flat surface. Special features of the filter housing:
- Viewing window for a functional check of the cleaning and for monitoring the filter gap
- Raw gas funnel with steep slope angles
- Pneumatic double acting raw gas dampers, make EBRO
- Delivery as prefabricated and functionally tested plant
- Pneumatic clean gas flaps for each post-filter chamber
- Manual clean gas flaps for each post-filter chamber
Robust construction

Highest containment level due to safe filter replacement
Circumferential double groove profiles on the filter openings for filter change using Safe Change technology. (bag-in-bag-out)
The filter bags are designed as foil bags made of polyethylene with gridded black strips consisting of polyethylene and carbon powder. This gives the filter bag dissipative properties and makes it suitable for combustible dusts and gases.
In addition, the foil bag is provided with welded-in side pockets to facilitate handling during filter change and to shorten the process time.
The rubber rings for fastening the bag in the double groove profile are designed as hollow cord rings, which ensures that the bag sits firmly and securely in the groove profile of the change frame. A tab on the rubber ring ensures easier handling during filter change.
Highest containment level due to safe filter replacement

Highest explosion protection
Ex100
The filter system is electrically conductive and does not generate its own ignition sources.
Ex200
Due to its explosion pressure shock resistant design, the filter system offers constructive explosion protection based on the principle of partial filling. The explosion pressure is relieved internally via the filter cells, which also serve as an effective flame arrester.
Dusts with a specific pmax of 10 bar can be handled, as the pressure surge is reduced internally to 1 bar. Due to this internal pressure relief, the system does not suffer any permanent damage even in the event of an explosion.
The offered filter unit is designed according to ATEX Directive 2014/34/EU and approved and certified by FSA Mannheim, notified body 0558.
In the event of an explosion, no permanent deformation occurs according to the explosion test, even with dusts up to a Kst value of 590 bar*m/s.
From a Kst value of 300 bar*m/s, a blocking slide valve for the primary filter cell and a flap monitoring system must be provided for this purpose.
After internal cleaning, filter replacement and functional testing, the filter system can continue to be operated without any further measures.
In the event of an explosion, no permanent deformation occurs according to the explosion test, even with dusts up to a Kst value of 590 bar*m/s.
From a Kst value of 300 bar*m/s, a blocking slide valve for the primary filter cell and a flap monitoring system must be provided for this purpose.
After internal cleaning, filter replacement and functional testing, the filter system can continue to be operated without any further measures.
Special Features:
- In the event of a dust explosion, the filter housing is not damaged
- The special arrangement of the filter cells acts as an effective flame arrester to prevent ignition on the clean gas side
- Explosion pressure and heat are dissipated via the filter cells.
No external pressure relief or explosion suppression measures are required, which is a huge cost advantage.
Highest explosion protection
Technische Information | |
---|---|
Filterklasse | H13/H14 nach DIN EN 1822 |
Volumenstrom | ab 250 m³/h |
Betriebsmodus | diskontinuierlich |
Rohgasstaubbeladung | < 5 mg/m³ |
Reingasstaubgehalt | < 0,0001 mg/m³ |
Staubarten | alle Staubarten |
Containment | bis OEB 5 |
Options
GMP compliant construction
The system housing is designed to be GMP-compliant. Protrusions and undercuts were avoided where technically feasible.
Raw gas hoppers, dust discharge and maintenance doors are enclosed, providing easy-to-clean surfaces. Furthermore, the back of the plant with raw gas duct and WIP system is also clad.
Filter qualification
The filter system is equipped with DEHS lances for qualifying the separation efficiency of the first and second filter stages:
- Test medium application in the raw gas channel
- Measuring lance for raw gas concentration determination in the hopper
- Measuring lances (3 pieces) after the primary filter stage for qualification
- Ring line for uniform feeding of the raw gas concentration upstream of the secondary filter stage
- Measuring lance for raw gas concentration determination
- Measuring lances (5 pieces) after the safety filter stage for qualification
The secondary filter stage is designed with the so-called tightness test. A test overpressure is applied to the test groove covered by the filter seal. The correct seating of the filter cell is validated by measuring the leakage flow (<16 l/h).
Qualified DEHS measurement
HETperformance stands for various options for checking the filter system in terms of design, functionality and safety.
These criteria are also important in the pharmaceutical industry:
- Is the plant and its components built safely?
- Can it be used in explosive atmospheres?
- Is the plant tight?
- Can it be used in clean rooms?
- Do any hazards emanate from the plant?
- Can it be used under containment conditions?
- Does the system serve its purpose?
- Can it filter the hazardous substances out of the air reliably and efficiently?
At the core of HETperformance are measurements and validations of the filter system for both optimization and protection of employees and the environment.
Through the wall
Through the Wall: The filter housing is enclosed by a circumferential stainless steel frame (L-profile), which allows flush integration into a cleanroom wall, for example.
Technologies


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Containment

Explosion protection
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