Bürkert 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 valve body and the diaphragms are available in all common materials and variants. The actuator has a compact, autoclavable design and is compatible with all other Bürkert diaphragm valves. An explosion-proof ATEX/IECEx device variant is available. The manual actuator possesses a visual position indicator with a reproducible stroke scale. The actuator also possesses an adjustable minimum and maximum stroke limitation and/or locking.

Key Features

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

General Technical Data

Product properties	Description
Forged steel valve body (VS)	Forged stainless steel 1.4435 in accordance with BN2 DIN EN 10222-5, F316L in accordance with ASTM A182/A182M and 316L in accordance with ASME BPE
Tube valve body (VP)	Stainless steel tube 1.4435-BN2 / UNS S31603 (316L) according to DIN 11866, ASTM A269 / A270, DIN EN 10217-7 / 10216-5
Cast valve body (VG)	Stainless steel precision casting 1.4435 / 316L
Plastic valve body	PVC-C, PVC-U, PP, PVDF
Diaphragm	EPDM (AD), PTFE/EPDM (EA), Advanced PTFE/EPDM (EU), laminate of GYLON® and EPDM (ER)
Actuator	Stainless steel/PPS
Diaphragm size	15...50
Nominal diameter	DN 08...DN 65 (1/4"...2 1/2")
Ambient temperature	-10...+130 °C (short-term up to +150 °C), autoclavable

Approvals and Conformities

• FDA: The diaphragms made of EPDM, PTFE/EPDM, Advanced PTFE/EPDM and laminate of GYLON® and EPDM comply with the Code of Federal Regulations published by the FDA.
• USP: The diaphragms are tested according to USP Class VI.
• EC Regulation 1935/2004: Suitable for use with food and beverages.
• Explosion Protection (Optional): EPS 18 ATEX 2 008 X II 2G Ex h IIC T4…T2 Gb / II 2D Ex h IIIC T135 °C…T300 °C Db. 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, PTFE/EPDM, Advanced PTFE/EPDM, Laminate of GYLON® and EPDM

INFO

Your product variant may differ from this illustration depending on the body and interface options.

Performance Specifications

Maximum Static Operating Pressure

Diaphragm size	Maximum static operating pressure [bar]	Tightening torque EPDM, FKM [Nm]	Tightening torque PTFE/EPDM, GYLON® [Nm]
15	10	0.8	1.7
20	10	0.9	3
25	10	1.2	3.5
32	10	2.5	4
40	10	4.5	7
50	10	6	11

WARNING

The tightening torques refer to the static media pressures specified above. Excessive torque can shorten the service life of the diaphragm. A tolerance of +10% applies to the tightening torques specified.

Pressure Temperature Diagram for Plastic Body

TIP

This information is important for material selection. Observe the permissible operating pressure depending on the medium temperature.

Installation and Operation

Setting Minimum and Maximum Stroke Limits

A minimum and maximum stroke limit can be set for Type 2973 (diaphragm sizes 15…50). The stroke limit is available as an option and is not integrated as standard. 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 (hexagon socket, width across flats 2) 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. The square on the spindle and the hexagon head of the adjusting sleeve must be correctly aligned.
5. Move the valve to the desired maximally open position.
6. Loosen the screw on the handwheel and remove the handwheel.
7. Pull the adjusting sleeve upwards and at the same time, screw anticlockwise until it comes to a stop. Maximum stroke is set.
8. Mount the handwheel on the actuator and tighten the screw with 0.9 Nm.

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 against unauthorized use with a padlock.

1. Push the locking pin down and rotate by 180° (either clockwise or anticlockwise). It may be necessary to turn the handwheel slightly so that the locking pin reaches its end position.
2. Insert a padlock through the bore in the locking pin and secure it.