Bürkert Type 2105 is an externally controlled diaphragm valve consisting of a pneumatically operated piston actuator, a diaphragm, and a tank bottom valve body. The proven and robust actuator with a stainless steel or PPS housing ensures reliable use in hygienic or aggressive ambient conditions. The flow-efficient valve bodies feature minimal dead space, enabling high flow rates and a wide range of applications in the food, beverage, biotechnology, and pharmaceutical industries.

The actuator features a compact, autoclavable design with gap-free seals. The integration of automation units (Type ELEMENT) is possible in all configuration levels, and a fieldbus interface can also be integrated. The system is highly integrated, featuring internal pilot air ducts that prevent the intake of ambient air.

General Technical Data

Feature	Specification
Block body material	Stainless steel block material 1.4435 (DIN EN 10088) / 316L (ASTM A479)
Diaphragm material	EPDM (AD), PTFE/EPDM (EA), Advanced PTFE/EPDM (EU), GYLON®/EPDM (ER)
Actuator material	DN 08...65: PPS DN 65...100: Stainless steel 1.4308
Standard surface quality	Internally electrically polished: Ra ≤ 0.38 μm (ASME BPE SF4) Internally mechanically polished: Ra ≤ 0.5 μm (ASME BPE SF1)
Maximum pilot pressure	10 bar (7 bar for actuator sizes 130, 225)
Operating medium	Neutral gases and liquids, highly purified, sterile, aggressive or abrasive media
Ambient temperature	-10 °C to +60 °C (autoclavable)

Control Functions

• Control function A (CF A): Pneumatically operated tank bottom valve, normally closed by spring force.
• Control function B (CF B): Pneumatically operated tank bottom valve, normally opened by spring force.
• Control function I (CF I): Pneumatically operated tank bottom valve on either side, switching position dependent on external control.

Approvals and Conformities

• Explosion Protection: ATEX (II 2G Ex h IIC T4…T2 Gb / II 2D Ex h IIIC T135 °C…T300 °C Db) and IECEx approved variants available.
• Hygiene & Food: Complies with 3-A Sanitary Standards, FDA Code of Federal Regulations, USP Class VI, and EC Regulation 1935/2004.

Material Specifications

No.	Element	Material
1	Valve body	Stainless steel
2	Diaphragm	EPDM, PTFE/EPDM, Advanced PTFE/EPDM, GYLON®/EPDM
3	Piston seal	FKM
4	Cover	Stainless steel 1.4561 (316Ti)
5	Actuator	Polyphenylene sulphide (PPS)
6	Transparent cap	Polysulfone (PSU)

Dimensions

Installation and Welding Instructions

Welding Precautions

Damage to the diaphragm or the actuator can occur when welding the valve body into the container base or the pipeline. In the case of devices with a welded connection, remove the actuator and diaphragm from the valve body before installation.

1. Weld the tank bottom valve body to the container base before the container is assembled. Weld the valve body in the middle of the container base so that the container can be optimally drained.
2. Weld the tank bottom valve body into the pipeline.
3. After welding the surface of the valve body, smooth by sanding if necessary and clean the valve body carefully.
4. Reinstall the actuator on the valve body following the specified tightening torques.

Explosion Hazard (ATEX/IECEx)

For devices used in potentially explosive atmospheres (Zones 1/21 and 2/22), ensure proper grounding of the actuator and valve body to prevent electrostatic discharge. Do not use media with a conductivity ≤100 pS/m if the flow velocity exceeds 1 m/s unless the pipeline is monitored to prevent running dry.