BURKERT Type 2973 is a manually operated 2/2-way diaphragm valve consisting of an actuator, a diaphragm, and a 2-way valve body. The manual actuator with a plastic handwheel allows for use in hygienic or aggressive environments. The flow-optimised and zero dead volume valve body enables high flow rates and versatile applications. The Type 2973 is equipped with a minimum and maximum stroke limiter and a locking mechanism. The actuator features a compact, autoclavable design and is compatible with all other Bürkert diaphragm valves.

Technical Data

Materials

Component	Material
Valve body	Forged stainless steel 316L/1.4435 BN2, Precision-cast stainless steel, Stainless steel tube, PVC-C, PVC-U, PP, PVDF
Actuator	Handwheel and diaphragm bonnet: PPS; Handwheel: PPS and diaphragm bonnet: stainless steel
Diaphragm	EPDM, PTFE/EPDM, advanced PTFE/EPDM, laminate made from GYLON® and EPDM, FKM

Operating Conditions

• Ambient temperature for actuators: -10 to +130 °C (up to +150 °C for short periods), autoclavable.
• Medium temperature (Stainless steel body): -10 to +150 °C.
• Medium temperature (Diaphragms):
  • EPDM: -10 to +143 °C (Steam sterilisation up to +150 °C for 60 min)
  • PTFE/EPDM: -10 to +130 °C (Steam sterilisation up to +140 °C for 60 min)

INFO

When using plastic cover caps for hexagon nuts and hexagon bolts, the maximum ambient temperature is limited to 60 °C (temporarily: 80 °C).

Permitted Medium Pressure

Diaphragm size	Maximum permitted medium pressure (EPDM/FKM)	Maximum permitted medium pressure (PTFE/advanced PTFE/GYLON®)
8 to 40	10 bar	10 bar
50	7 / 10 bar	7 / 10 bar
65 to 80	10 bar	10 bar
100	6 bar	6 bar

Installation

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.

Information for the Correct Installation Position

Installation position is any, preferably with the actuator facing up. It is the responsibility of the installer and the operator to ensure self-draining.

Observe the rules for self-draining during installation:

1. Inclination angle of the pipeline: The angle of inclination should correspond to the angle of inclination of the pipeline. We recommend the inclination angles according to the valid ASME BPE.
2. Self-draining angle for valve body: The self-draining angle 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.

Devices with Welded or Adhesive Connection

WARNING

To prevent damage, dismantle the actuator and diaphragm 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 or bond the valve body into the pipeline.
4. Clean the valve body thoroughly and place the actuator together with diaphragm on the valve body.
5. Tighten each fastening screw in 3 stages (approx. 1/3, approx. 2/3, 3/3 of the tightening torque) crosswise.

Operation and Settings

Setting Minimum and Maximum Stroke Limits (Type 297x)

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. Minimum stroke is set.
4. Mount the handwheel on the actuator and move the valve to the desired maximally open position.
5. Loosen the screw on the handwheel and remove the handwheel.
6. Pull the adjusting sleeve upwards and at the same time, screw anticlockwise until it comes to a stop. Maximum stroke is set.
7. Mount the handwheel on the actuator and tighten the screw with 0.9 Nm.

Locking the Handwheel

For Type 2973 (diaphragm size 15…50), a locking mechanism is available as an option to prevent accidental or unauthorised operation. The locking pin has a bore (Ø 3.8) and can be secured against unauthorised use with a padlock.

Maintenance

TIP

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.

The following factors influence the service life of the diaphragm: diaphragm material, medium, medium pressure, medium temperature, and closing force. Replace the diaphragm if there are leaks and conduct regular inspections of the relief bore.