The Burkert 20081992 Type 2935 manually operated diaphragm valve consists of a manually operated actuator, a diaphragm, and a tank bottom valve body. The manual actuator with a plastic (PPS) or stainless steel handwheel is available with a diaphragm bonnet made of stainless steel or plastic, ensuring reliable use in hygienic or aggressive ambient conditions. The flow-optimised valve body with minimum dead space enables high flow values and a wide range of possible applications.

The actuator has a compact, autoclavable design and is equipped with an integrated visual position indicator, a reproducible stroke scale, and an adjustable closing limiter. The 20081992 variant features a DN 150 flange connection, an EPDM high-temperature diaphragm, and a stainless steel block material body (1.4435/316L), making it CIP and SIP capable for demanding sanitary processes.

Product Structure and Variants

By manually overriding the handwheel, the force is transmitted via a spindle and the valve is opened or closed. Turning the handwheel anticlockwise opens the valve, turning it clockwise closes it. To protect the actuator, it is recommended not to close the actuator with more force than is required to close the valve tightly.

General Technical Data

Product Properties	Description
Block body material	Stainless steel block material 1.4435 according to DIN EN 10088 and 316L according to ASTM A479 / A479M
Diaphragm material	EPDM (AD), PTFE/EPDM (EA), advanced PTFE/EPDM (EU), laminate of GYLON® and EPDM (ER)
Actuator material	Stainless steel/PPS, PPS/PPS, stainless steel/stainless steel
Standard surface quality	Internally electrically polished: Ra ≤ 0.38 μm (ASME BPE SF4/DIN HE4); Internally mechanically polished: Ra ≤ 0.5 μm (ASME BPE SF1)
Operating medium	Neutral gases and liquids, highly purified, sterile, aggressive or abrasive mediums
Medium temperature (EPDM)	-10...+143 °C (steam sterilisation + 150 °C for 60 min)
Ambient temperature	-10...+130 °C (short-term up to + 150 °C), autoclavable

Approvals and Conformities

• Foods and Beverages/Hygiene:
  • 3-A Sanitary Standards Inc.: The products comply with 3-A Sanitary Standards Inc (3-A SSI).
  • FDA: The diaphragms comply with the Code of Federal Regulations published by the FDA.
  • USP: The diaphragms are tested according to USP Class VI.
  • EC Regulation 1935/2004: Suitable for use with food and beverages.

Materials

No.	Element	Material
1	Handwheel	Polyphenylene sulphide (PPS), stainless steel 1.4308
2	Visual position indicator	Polyamide (PA), stainless steel 1.4305
3	Valve spindle	Stainless steel 1.4305
4	Diaphragm bonnet	Stainless steel 1.4308, polyphenylene sulphide (PPS)
5	Diaphragm	EPDM (AD), PTFE/EPDM (EA), advanced PTFE/EPDM (EU), laminate of GYLON® and EPDM (ER)
6	Valve body	Stainless steel block material

Dimensions

Manual Actuator with Tank Bottom Body

Note: Dimensions in mm, unless otherwise stated.

Diaphragm size	C2	C3
8	69	71
15	103	101
20	116	115
25	127	129
40	182	201
50	203	217
65	265	305
80	336	278
100	300	370

Installation

DANGER

Risk of injury due to high pressure and escaping medium. Switch off the pressure before working on the device or system. Vent or empty the lines.

Welding Tank Bottom Body

Observe the following sequence:

1. Weld the tank bottom body to the container base before the container is assembled. Note: weld the tank bottom body in the middle of the container base so that the container can be optimally drained.
2. Weld the tank bottom body into the pipeline. Ensure that pipelines are in alignment. Support and align pipelines. To ensure that the pipeline is self-draining, we recommend the inclination angles according to the valid ASME BPE.

TIP

Recommendations For information on containers and instructions for welding, refer to the ASME VIII Division I standard. Check the batch number indicated on the manufacturer’s certificate 3.1 supplied before starting welding work.

WARNING

Before welding, note the following:

• Only use welding materials which are suitable for the tank bottom body.
• The tank bottom valve must not collide with any other installation part. The actuator must be easy to install and remove.
• Dismantle the actuator and diaphragm before welding or bonding the valve body to prevent damage.

Explosion Protection (ATEX/IECEx)

For devices with the PX51 code (EPS 18 ATEX 2008 X / IECEx EPS 18.0007 X), the valve actuator is suitable for use as category 2 equipment in Zones 1/21 and 2/22.

DANGER

Explosion risk due to electrostatic discharge! If statically charged equipment or personnel suddenly discharge, there is a risk of explosion in potentially explosive atmospheres.

• Take appropriate measures to ensure that static electricity does not accumulate.
• Only wipe the surface of the device gently with a damp or anti-static cloth.
• Ground the actuator and valve body.

Maintenance

When used in accordance with the operating instructions, the actuator of the diaphragm valve is maintenance-free.

Inspection intervals:

• After the first steam sterilisation, or when required, retighten the fastening screws crosswise.
• After a maximum of 10^5 switching cycles check the diaphragm for wear. Muddy and abrasive media require correspondingly shorter inspection intervals.

Replacing the diaphragm:

1. Rotate the handwheel counterclockwise until it comes to a stop (OPEN position).
2. Loosen the fastening screws crosswise and remove the actuator with diaphragm from the valve body.
3. Rotate the handwheel clockwise until it comes to a stop (CLOSED position).
4. Unbutton or unscrew the old diaphragm. When fastening with a bayonet catch, loosen the diaphragm by rotating it 90°.
5. Install a new diaphragm in the actuator.
6. Tighten each fastening screw in 3 stages (approx. 1/3, approx. 2/3, 3/3 of the tightening torque) crosswise. The diaphragm should be positioned and pressed evenly around the actuator and valve body.