Burkert Type 2973 manually operated diaphragm valve consists of a manually operated actuator, a diaphragm, and a 2-way body. The manual actuator with a plastic handwheel ensures 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.

Key Features

• Valve body and diaphragm are available in different materials and variants.
• Wetted surfaces from Ra ≤ 0.38 µm to ≤ 1.6 µm (optionally electropolished).
• Available in all common connection sizes and variants.
• Integrated locking.
• Minimum and maximum stroke limitation.

Approvals and Conformities

• FDA: The diaphragms made of EPDM, PTFE/EPDM, Advanced PTFE/EPDM, and GYLON/EPDM comply with the Code of Federal Regulations.
• USP: Tested according to USP Class VI.
• EC Regulation 1935/2004: Suitable for use with food and beverages.
• Explosion Protection (ATEX/IECEx): Optional category 2 device suitable for zone 1/21 and zone 2/22 (EPS 18 ATEX 2 008 X / IECEx EPS 18.0007X).

Material Specifications

No.	Element	Material
1	Lock pin	Stainless steel 1.4305
2	Screw	Stainless steel A2
3	Handwheel cover	Polyamide (PA)
4	Handwheel	Polyphenylene sulphide (PPS)
5	Visual position indicator	Polyamide (PA)
6	Valve spindle	Stainless steel 1.4305
7	Diaphragm socket	Stainless steel 1.4308
8	Diaphragm	EPDM (AD), PTFE/EPDM (EA), Advanced PTFE/EPDM (EU), Laminate of GYLON and EPDM (ER)

Performance Specifications

Maximum Permitted Medium Pressure

Diaphragm size	EPDM/FKM (bar)	PTFE/Advanced PTFE/GYLON (bar)
8 to 40	10	10
50	7 / 10	7 / 10
65 to 80	10	10
100	6	6

Self-Draining Installation

To ensure self-draining, the installation position should be carefully aligned. The self-draining angle (α) depends on the valve body size and the inner diameter of the port connection (DN). The marking on the port connection of the valve body serves as an orientation aid and must point upwards.

Operation and Adjustments

Setting Stroke Limit

A minimum and maximum stroke limit can be set for Type 2973 (diaphragm sizes 15…50). An adjusting sleeve is used for this purpose.

1. By turning the handwheel clockwise, the valve is moved to the closed position.
2. Loosen the screw on the handwheel and remove the handwheel.
3. Screw the adjusting sleeve clockwise until it comes to a stop to set the minimum stroke.
4. Pull the adjusting sleeve upwards and screw anticlockwise to set the maximum stroke.

Locking the Handwheel

A locking mechanism is available as an option to prevent accidental or unauthorized operation. The locking pin has a bore (Ø 3.8) and can be secured with a padlock. Push the locking pin down and rotate by 180° to lock.