Diaphragm Valve Manufacturer in Germany

Diaphragm valves isolate or regulate fluid by moving a flexible diaphragm toward or away from the valve body’s sealing surface. The diaphragm separates the operating mechanism from the process medium, reducing the number of wetted moving components and making the valve suitable for corrosive, abrasive, viscous and solids containing fluids.

Fluid Isolation Using a Flexible Diaphragm

• The diaphragm is connected to a compressor or stem mechanism located above the flow passage.
• During closing, the compressor moves downward and presses the diaphragm against the body weir or sealing surface.
• During opening, the compressor retracts and allows the diaphragm to lift away from the flow path.
• Because the operating stem does not pass directly through the process boundary, conventional stem packing is not required in the same manner as many gate, globe or ball valve designs.
• The diaphragm also isolates the bonnet and actuator components from direct contact with the process medium.

This makes the design useful for fluids that are:

• Corrosive
• Abrasive
• Viscous
• Contaminated with suspended solids

provided the diaphragm and body materials are compatible.

Weir Type and Straight Through Designs

Weir-Type Diaphragm Valve

• Raised weir with short diaphragm travel
• Good throttling and reliable shut-off
• Reduced diaphragm flexing
• Used in chemical, water-treatment and process systems

Straight-Through Diaphragm Valve

• Open flow path without a raised weir
• Lower flow resistance
• Suitable for viscous, slurry and fibrous media
• Reduced solids accumulation
• Requires greater diaphragm travel

Body and Compressor Construction

Current standard configurations can use cast iron or ductile iron bodies.

Cast Iron

Suitable for moderate-pressure water, effluent and compatible general process applications.

Ductile Iron

Provides higher mechanical strength and impact resistance and is commonly used for water, wastewater and selected slurry systems.

The compressor distributes stem force across the diaphragm during closing.

Internal operating components are normally located outside the process medium, helping reduce corrosion exposure of the stem and actuator mechanism.

For corrosive applications, the body can be protected with a suitable lining or coating where required by the actual design.

Technical Specifications

Parameter	Typical Specification
Nominal Size	DN15–DN300
Pressure Rating	PN10, PN16, PN25 / Class 150 depending on design
Body Designs	Weir Type, Straight Through
Body Materials	Cast Iron, Ductile Iron
Diaphragm Materials	EPDM, NBR, FKM, PTFE-Faced
Lining Options	Rubber, Ebonite, PTFE/PFA where offered
End Connections	Flanged, Threaded; other configurations design-dependent
Actuation	Handwheel, Pneumatic, Electric
Typical Temperature	Approximately -10°C to +150°C depending primarily on diaphragm material
Flow Direction	Generally bidirectional, subject to specific design
Diaphragm Valve Standard	EN 13397 for applicable metallic diaphragm valves
Face to Face	EN 558 / applicable manufacturer dimensions
Flange Standards	EN 1092 / ASME B16.5 according to body and project requirements
Testing	EN 13397 / EN 12266-1 or applicable project requirements

Manual and Automated Operation

Handwheel Operation

Manual diaphragm valves use a handwheel and threaded stem to move the compressor toward or away from the diaphragm.

This configuration is suitable where:

• Operation is infrequent
• Local control is acceptable
• Automation is not required

Pneumatic Actuation

A pneumatic actuator uses compressed air to move the compressor.

Pneumatic operation is suitable for:

• Frequent cycling
• Remote isolation
• Automated process control
• Fail-open or fail-closed configurations where applicable

Electric Actuation

Electric actuators provide motor-driven operation and can be integrated with PLC, DCS or local control panels.

On/off or modulating operation may be provided where the selected valve and actuator are suitable for control duty.

Actuator thrust must be matched to valve size, pressure and diaphragm closing force.

Media Compatibility and Temperature Limits

Diaphragm valve suitability is often determined more by the diaphragm and lining materials than by the metallic body.

Selection should consider:

• Chemical composition
• pH
• Solids concentration
• Fluid viscosity
• Operating temperature
• Pressure
• Abrasiveness
• Cleaning chemicals
• Frequency of operation

A body material may remain suitable at a temperature where the diaphragm is already above its practical operating limit.

Likewise, a PTFE-faced diaphragm can provide strong chemical resistance but may have different pressure and flex life characteristics than an elastomeric diaphragm.

Pressure temperature limits should therefore be based on the complete valve construction.

Corrosive and Abrasive Fluid Applications

Diaphragm valves are used in systems where keeping the operating mechanism separated from the process fluid provides an advantage.

Typical applications include:

• Water treatment
• Wastewater and effluent
• Chemical dosing
• Corrosive chemical transfer
• Mining and mineral processing
• Slurry pipelines
• Pulp and paper
• Power plant auxiliary systems
• Industrial process water
• Viscous fluid handling

Weir type designs are well suited to isolation and throttling of clean or corrosive fluids, while straight through valves provide a more open passage for slurry, fibrous or viscous media.