BURKERT 20099875 Type 2961 is a manually operated 2-way globe control valve designed for excellent control accuracy under demanding operating conditions. It consists of a robust manual actuator and a high-quality stainless steel globe valve body with exchangeable seats. The precise spindle guide enables reliable control, while the PEEK seal guarantees tight shut-off even at high temperatures up to 230 °C. The actuator is made of high-quality plastic, features a visual position indicator, and is suitable for use in demanding environments.

This specific model features a DN 50 flange connection, a 110 mm handwheel, and is ATEX/IECEx certified for use in potentially explosive atmospheres.

Product Features

• Excellent control accuracy: Achieved through an equal percentage flow characteristic and precise spindle guidance.
• Exchangeable valve seats: Enables perfect coordination under the most demanding operating conditions.
• Robust actuator: Made of Polyphenylene sulphide (PPS) with a visual position indicator and reproducible stroke scale.
• High-temperature capability: The PEEK seat seal allows for medium temperatures up to 230 °C.
• Explosion protection: Certified as a category 2 device suitable for zone 1/21 and zone 2/22.

Function and Operation

By manually overriding the handwheel, the force is transmitted via a spindle and the valve is opened or closed. Turning the handwheel anticlockwise opens the valve, turning it clockwise closes it.

Position Indicator

When turning the handwheel anticlockwise, the reproducible stroke scale becomes visible between the position indicator and the handwheel.

INFO

The scale on the handwheel determines the rotation position of the handwheel (50 positions). The reproducible stroke scale shows, depending on the bottom edge of the handwheel, the relative position of the valve (valve opening) and acts as a fixation point for determining the rotation position.

Flow Direction

The valve seat is always closed against the medium flow. The flow direction should therefore be set such that the valve reaches the flow beneath the valve seat.

Flow Characteristic

The Type 2961 utilizes a cone of equal percentage. The theoretical rangeability (Kvs/Kvo) is 50:1.

Materials

No.	Element	Material
1	Cover	Polyamide (PA)
2	Screw	Stainless steel 1.4301
3	Locking device	Stainless steel 1.4305
4	Handwheel	Polyphenylene sulphide (PPS)
5	Visual position indicator with scale	Polyamide (PA)
6	Packing gland	PTFE V-rings (filled), with spring compensation
7	Stem	Stainless steel 1.4401 or 1.4404
8	Spindle guide	Stainless steel 1.4404 (316L), PTFE filled
9	Housing seal	Graphite
10	Control cone	1.4571 (optionally hardened)
11	Seat seal	PEEK
12	Valve seat with O-ring	Stainless steel 1.4571, EPDM
13	Valve body	Stainless steel 316L/CF3M

Dimensions

Body with Flange Connection (DN 50)

Dimensions in mm, unless otherwise stated.

DN	Ø DF	LF	Ø BF	AF	Ø D	A x α	Ø MF
50	165	230	125	20	18	4 × 90°	56.3

Performance Specifications

Fluidic Data (DN 50)

• Seat size: 50 mm
• Handwheel diameter: 110 mm (M)
• Operating pressure max: 20 bar (Seat leakage class VI)
• Theoretical rangeability: 50:1
• Kvs value: 37.0 m³/h

Kv value at stroke [m³/h]:

5%	10%	20%	30%	40%	50%	60%	70%	80%	90%	100%
0.90	1.1	1.9	2.9	4.5	6.8	10.5	15.5	22.0	29.5	37.0

Installation and Adjustments

WARNING

Risk of injury due to high pressure and escaping medium. Switch off the pressure before working on the device or system. Vent or drain the lines.

Set Stroke Limit

Setting the minimum and maximum stroke limit is possible as an option using an adjusting sleeve.

1. By turning the handwheel clockwise, the valve is moved to the closed position.
2. Loosen the screw on the handwheel and remove it.
3. Screw adjusting sleeve clockwise until it comes to a stop to set the minimum stroke.
4. Mount handwheel, move the valve to the desired maximally open position, and remove the handwheel again.
5. Pull adjusting sleeve upwards and at the same time, screw anticlockwise until it comes to a stop to set the maximum stroke.

Lock Handwheel

It is an option to lock the handwheel to prevent unintentional or unauthorised operation of the valve. Handwheel size M can be locked in 13 locking positions per revolution.

The locking pin has a bore (Ø 3.8) and can be secured against unauthorised use with a padlock.

Explosion Protection (ATEX / IECEx)

For devices used in potentially explosive atmospheres (Zone 1/21 and Zone 2/22), strict adherence to safety guidelines is required.

DANGER

Risk of explosion due to electrostatic charge! If a statically charged device or person discharges suddenly, there is an explosion risk in the Ex area.

• Take appropriate measures to ensure that no electrostatic charge can build up in the Ex area.
• Only clean the device surface by wiping it gently with a damp or antistatic cloth.
• Ground the actuator and the valve body.

Device Grounding:

1. Ground the valve body. To establish potential equalization, ground the valve body to the pipeline system using a conductive connection.
2. Ground the conductive components of the device. Conductive components must be grounded separately using a grounding strap clip or grounding terminal.