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 use in 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. The manual actuator is equipped with an integrated visual position indicator, a reproducible stroke scale, and an adjustable closing limiter.

Approvals and Conformities

The Type 2935 diaphragm valve meets stringent industry standards for hygienic and potentially explosive environments.

Conformity / Approval	Description
ATEX / IECEx	Category 2 device suitable for zone 1/21 and zone 2/22. Ex h IIC T4...T2 Gb / Ex h IIIC T135 °C...T300 °C Db.
3-A Sanitary Standards	Products comply with 3-A Sanitary Standards Inc (3-A SSI).
FDA	Diaphragms made of EPDM, PTFE/EPDM, advanced PTFE/EPDM, and GYLON®/EPDM comply with the Code of Federal Regulations published by the FDA.
USP Class VI	Diaphragms are tested according to United States Pharmacopeial Convention (USP) Class VI.
EC 1935/2004	Diaphragms are suitable for use with food and beverages according to EC Regulation 1935/2004/EC.
TA Luft	Technical instruction on air quality control.

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 1.4435 according to DIN EN 10088 and 316L according to ASTM A479 / A479M

Dimensions

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

WARNING

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

1. Weld the tank bottom body to the container base before the container is assembled. 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

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.

Setting Minimum Stroke Limit

A minimum stroke limit can be set for Type 2935. This setting also serves as a closing limiter to protect the diaphragm. A hexagon nut is used to do this.

1. By turning the handwheel clockwise, the valve is moved to the closed position.
2. Loosen the screw on the handwheel (hexagon socket, width across flats 2) and remove the handwheel.
3. Screw the hexagon nut as far as it will go. Minimum stroke is set.
4. Mount the handwheel on the actuator. The square on the spindle and the hexagon head of the nut must be correctly aligned to the geometry of the handwheel so that they fit into each other.
5. Tighten the screw on the handwheel with 0.9 Nm. If necessary, bond the screw to ensure a permanent hold.

Maintenance

Replacing the Diaphragm

1. Clamp the valve body in a collet (only for valves which have not yet been installed).
2. Rotate the handwheel counterclockwise until it comes to a stop (OPEN position).
3. Loosen the fastening screws crosswise and remove the actuator with diaphragm from the valve body.
4. Rotate the handwheel clockwise until it comes to a stop (CLOSED position).
5. Unbutton or unscrew the old diaphragm. When fastening with a bayonet catch, loosen the diaphragm by rotating it 90°.
6. Install a new diaphragm in the actuator.
7. Rotate the handwheel counterclockwise until it comes to a stop (OPEN position).
8. Align the diaphragm. Identification tab is at a 90-degree angle to the flow direction.
9. Place the actuator together with diaphragm on the valve body.
10. Slightly tighten the fastening screws crosswise.
11. Close and open the diaphragm valve twice to position the diaphragm correctly.
12. Close the diaphragm valve again and open by about 20%.
13. 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.