Burkert 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 or stainless steel handwheel is available with a diaphragm bonnet made of stainless steel or plastic, ensuring suitability for hygienic or aggressive ambient conditions. The flow-optimized 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 compatible with all other Bürkert diaphragm valves. An explosion-proof ATEX/IECEx device variant is available. The manual actuator is equipped with an integrated visual position indicator, a reproducible stroke scale, and an adjustable closing limiter.

General Technical Data

Product properties	Description
Block body (VH/VI)	Stainless steel block material 1.4435 according to DIN EN 10088 and 316L according to ASTM A479 / A479M / ASME BPE
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
Diaphragm size	8...100
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) (externally: Ra ≤ 1.6 μm)
Operating medium	Neutral gases and liquids, highly purified, sterile, aggressive or abrasive mediums
Nominal diameter	DN 06...DN 100 (1/8"...4")
Ambient temperature	-10...+130 °C (short-term up to + 150 °C), autoclavable

Medium Temperature

Material	Temperature Range
EPDM (AD)	-10...+143 °C (steam sterilisation + 150 °C for 60 min)
PTFE/EPDM (EA)	-10...+130 °C (steam sterilisation + 140 °C for 60 min)
Advanced PTFE/EPDM (EU)	-5...+143 °C (steam sterilisation + 150 °C for 60 min)
Laminate of GYLON® and EPDM (ER)	-5...+130 °C (steam sterilisation + 140 °C for 60 min)

Approvals and Conformities

• Explosion protection: ATEX / IECEx (Category 2 device suitable for zone 1/21 and zone 2/22).
• 3-A Sanitary Standards Inc.: 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 Regulation 1935/2004: Diaphragms are 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

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

Tank Bottom Body with Welded Connection

(Dimensions in mm, unless otherwise stated. Refer to the full datasheet for comprehensive dimensional tables covering DIN EN ISO 1127, DIN 11850, ASME BPE, and SMS 3008 standards.)

Tank Bottom Body with Clamp Connection

INFO

Clamp dimensions must be added to the welded connection dimensions.

Performance Specifications

Maximum Permitted Medium Pressure

Diaphragm size	Maximum static operating pressure [bar]	Tightening torque EPDM, FKM [Nm]	Tightening torque PTFE/EPDM, advanced PTFE/EPDM, GYLON® [Nm]
8	10	0.6	1.1
15	10	0.8	1.7
20	10	0.9	3
25	10	1.2	3.5
32	10	2.5	4
40	10	4.5	7
50	10	6	11
65	10	8	21
80	10	12	23
100	10	13	24

WARNING

The tightening torques refer to the static media pressures specified above. Excessive torque can shorten the service life of the diaphragm. A tolerance of + 10 % applies to the tightening torques specified.

Installation and Welding

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. 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.

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.
• The actuator and diaphragm must be dismantled before welding or bonding the 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 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.