BURKERT Type 2935 (SKU 20089832) is a manually operated diaphragm valve consisting of a manual actuator, a PTFE/EPDM diaphragm, and a stainless steel tank bottom valve body. The manual actuator features a PPS (Polyphenylene sulphide) handwheel and bonnet, ensuring reliable use in hygienic or aggressive ambient conditions. The flow-optimized tank bottom body with minimum dead space enables high flow values and is ideal for highly purified, sterile, or aggressive media. The actuator has a compact, autoclavable design and is equipped with an integrated visual position indicator, a reproducible stroke scale, and a single min-stroke limiter (closing limiter).

This specific model features a DN 65 Bürkert-tank bottom flange for the primary connection and a 19.05 x 1.65 (Cl: 25.0) secondary port connection, utilizing a size 15 diaphragm. It is fully CIP and SIP capable, making it suitable for pharmaceutical and food & beverage applications.

Approvals and Conformities

The Type 2935 valve is designed to meet stringent industry standards:

• Explosion Protection: ATEX II 2 G Ex h IIC T4...T2 Gb / II 2 D Ex h IIIC T135°C...T300°C Db, and IECEx Ex h IIC T4...T2 Gb / Ex h IIIC T135°C...T300°C Db.
• Hygiene and Food: FDA-compliant, USP Class VI-compliant, and EC Regulation 1935/2004 compliant.
• Certifications: Includes Manufacturer's test certificate 3.1 and Factory certification 2.1 for the membrane.

Materials

Element	Material
Handwheel	Polyphenylene sulphide (PPS)
Visual position indicator	Polyamide (PA), stainless steel 1.4305
Valve spindle	Stainless steel 1.4305
Diaphragm bonnet	Polyphenylene sulphide (PPS)
Diaphragm	PTFE with EPDM backing membrane
Valve body	Stainless steel block material 1.4435 (DIN EN 10088) and 316L (ASME BPE)

Function and Position Indicator

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.

Turning the handwheel counterclockwise reveals the yellow position indicator and the scale marked on it as the valve opens further. The scale on the handwheel determines the rotation position of the handwheel (30 positions for Type 293x). The stroke scale shows the relative position of the valve and serves as a fixation point for determining the rotation position.

WARNING

To protect the actuator, do not close the actuator with more force than is required to close the valve tightly. The visibility of the yellow mark is not directly correlated with the closed position of the valve.

Dimensions

Manual Actuator with Tank Bottom Body

Diaphragm size	C2 [mm]	C3 [mm]
15	103	101

Tank Bottom Body with Welded Connection

(Note: Dimensions vary based on the specific pipe standard. Refer to the full datasheet for comprehensive welded connection tables across DIN, ISO, and ASME BPE standards.)

Tank Bottom Body with Clamp Connection

(Note: Clamp dimensions must be added to the welded connection dimensions.)

Installation: Welding Tank Bottom Body

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.

Recommendations for welding 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

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.

Preparatory Work: The actuator and diaphragm must be dismantled before welding or bonding the valve body.

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. Weld the valve body into the pipeline/tank.
4. After welding, smooth the body surface (if necessary) by sanding and clean the valve body thoroughly.

Setting 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.
5. Tighten the screw on the handwheel with 0.9 Nm.

WARNING

Damage to the device by incorrectly positioning the hexagon nut. Do not screw the hexagon nut in the area of the square. Only use minimum stroke limit in the 0…25 % opening stroke range.

Maintenance and Diaphragm Replacement

The actuator of the diaphragm valve is maintenance-free when used in accordance with the operating instructions. However, the diaphragm is a wear part.

• 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 (Size 15 - Bayonet Catch):

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. Loosen the PTFE diaphragm bayonet by rotating it 90° and remove it.
5. Insert the new PTFE diaphragm and fix it by turning it 90°.
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 tightening torque for Size 15 with PTFE diaphragm on a stainless steel body is 4 Nm.