Burkert Type 2935 (SKU 20075522) manually operated diaphragm valve consists of a manually operated actuator, a diaphragm, and a tank bottom valve body. The manual actuator with a plastic 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.

Technical Data

Product Properties	Description
Block body (VH/VI)	Stainless steel block material 1.4435 according to DIN EN 10088 and 316L according to ASME BPE (Table MM-2.1.1, Ed. 2024)
Diaphragm	EPDM (AD), PTFE/EPDM (EA), advanced PTFE/EPDM (EU), laminate of GYLON® and EPDM (ER)
Actuator	Stainless steel/PPS, PPS/PPS, stainless steel/stainless steel
Standard surface quality	Internally electrically polished: Ra ≤ 0.38 μm (ASME BPE SF4/DIN HE4) (externally: Ra ≤ 1.6 μm)
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

Material Specifications

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

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 suitable for zone 1/21 and zone 2/22.
• 3-A Sanitary Standards: The products comply with 3-A Sanitary Standards Inc (3-A SSI).
• FDA: Diaphragms comply with the Code of Federal Regulations published by the FDA.
• USP: Diaphragms are tested according to USP Class VI.
• EC 1935/2004: Diaphragms are suitable for use with food and beverages.

Explosion Hazard due to Electrostatic Discharge

If statically charged devices or persons discharge suddenly, there is an explosion risk in the potentially explosive area.

• Take appropriate measures to ensure that no electrostatic charge can build up in the potentially explosive area.
• Only clean the device surface by wiping it gently with a damp or anti-static cloth.
• Ground the actuator and valve body.

Dimensions

Manual Actuator with Tank Bottom Body

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

(Dimensions in mm, unless otherwise stated)

Installation

Welding Tank Bottom Body

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.

Recommendations for welding:

1. Weld the tank bottom body to the container base before the container is assembled. It is possible to weld onto a ready-assembled container but it is more difficult. 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.

Preparation

The actuator and diaphragm must be dismantled before welding or bonding the valve body to prevent damage.

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 10⁵ 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. Rotate the handwheel counterclockwise until it comes to a stop (OPEN position).
7. Align the diaphragm. Identification tab is at a 90-degree angle to the flow direction.
8. Place the actuator together with diaphragm on the valve body.
9. 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.