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 polyphenylene sulphide (PPS) 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 possesses a visual position indicator with a reproducible stroke scale. The actuator also features an adjustable minimum and maximum stroke limitation and a locking mechanism.

Approvals and Conformities

The device complies with the following approvals and conformities (depending on the variant):

• Explosion Protection: ATEX/IECEx Category 2 device suitable for zone 1/21 and zone 2/22 (EPS 18 ATEX 2 008 X / IECEx EPS 18.0007X).
• Foods and Beverages/Hygiene: FDA (Code of Federal Regulations), USP Class VI, and EC Regulation 1935/2004 for EPDM, PTFE/EPDM, Advanced PTFE/EPDM, and GYLON/EPDM diaphragms.
• Others: TA Luft (Technical instruction on air quality control).

Materials

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)
9	Valve body	Forged steel, Tube, Cast, or Plastic (PVC-C, PVC-U, PP, PVDF)

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 counterclockwise opens the valve, revealing the yellow position indicator and the scale marked on it as the valve opens further.

Performance Specifications

Medium Pressure

The maximum permitted medium pressure depends on the diaphragm size and material.

Diaphragm size	Maximum static operating pressure [bar]
8 to 40	10
50	7 (for PPS handwheel) / 10

Pressure-Temperature Diagram for Plastic Body

Observe the permissible operating pressure depending on the medium temperature for plastic valve bodies.

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.

Installation Position for Self-Draining

The installation position can be any, but preferably with the actuator facing up. It is the responsibility of the installer and the operator to ensure self-draining.

• The angle of inclination should correspond to the angle of inclination of the pipeline (recommended according to ASME BPE).
• 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 must point upwards.

Setting Stroke Limit

A minimum and maximum stroke limit can be set for Type 2973 (diaphragm sizes 15 to 50) using an adjusting sleeve.

1. Turn the handwheel clockwise to move the valve to the closed position.
2. Loosen the screw on the handwheel and remove it.
3. Screw the adjusting sleeve clockwise until it comes to a stop to set the minimum stroke.
4. Move the valve to the desired maximally open position, remove the handwheel, and pull the adjusting sleeve upwards while screwing counterclockwise to set the maximum stroke.

Locking the Handwheel

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