The 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 reliable use in hygienic or aggressive ambient conditions. The flow-optimized tank bottom valve body features minimum dead space, enabling 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.

General Technical Data

Product Properties	Description
Block body material	Stainless steel block material 1.4435 according to DIN EN 10088 and 316L according to ASME BPE
Diaphragm material	PTFE with EPDM backing membrane (SKU 20142411); EPDM, advanced PTFE/EPDM, GYLON®/EPDM also available
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)
Medium temperature	-10...+130 °C (PTFE/EPDM); steam sterilisation +140 °C for 60 min
Ambient temperature	-10...+130 °C (short-term up to +150 °C), autoclavable

Approvals and Conformities

• Food and Beverage / Hygiene: FDA (Code of Federal Regulations), USP Class VI, EC Regulation 1935/2004, 3-A Sanitary Standards Inc.
• Explosion Protection: ATEX / IECEx (Category 2 device suitable for zone 1/21 and zone 2/22).

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	PTFE/EPDM (EA), EPDM (AD), 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 (mm)	C3 (mm)
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. Refer to the full datasheet for comprehensive size charts across all standards including DIN EN ISO 1127, ASME BPE, and SMS 3008).

Tank Bottom Body with Clamp Connection

INFO

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:

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 and properly supported.

WARNING

To prevent damage, dismantle the actuator and diaphragm before welding the valve body. Only use welding materials which are suitable for the tank bottom body.

Self-Draining Installation

It is the responsibility of the installer and the operator to ensure self-draining. The self-draining angle (α) depends on the valve body size and the inner diameter of the port connection. The marking on the port connection of the valve body serves as an orientation aid and must point upwards.

Tightening Torques

When installing the device, 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 all around the actuator and valve body.

Diaphragm size	Tightening torque for PTFE / advanced PTFE / GYLON® (Nm)
15	4
25	6
40	10
50	15
65	30
80	40

(A tolerance of +10 % of the respective tightening torque applies to all values).

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

The diaphragm is attached via a bayonet catch (sizes 15-100 for PTFE) or a threaded connection (sizes 25-100 for EPDM/FKM).

TIP

For diaphragms with threaded connection: First screw on the diaphragm hand-tight, then loosen it by one-half turn anticlockwise to prevent damage due to an energised pin.

WARNING

For diaphragms with a bayonet catch: If the insert is not removed when switching from EPDM to PTFE, a diaphragm with a bayonet catch can still be fitted, which can severely damage the diaphragm and valve body.