The Burkert Type 2961 control valve consists of a manual actuator and a globe valve body with exchangeable seats made of high-quality stainless steel. Each globe valve body can be equipped with up to 8 valve seat sizes and reaches the desired flow characteristic curve in interaction with parabolic cones. The precise spindle guide enables control, even under demanding operating conditions.

A soft PTFE or PEEK seal guarantees reliable sealing. The actuator is made of high-quality plastic and is suitable for use in demanding environments. It possesses a visual position indicator and can be optionally equipped with stroke limitation and locking. The packing gland uses tried-and-tested V-seals and possesses spring compensation, which means that it does not need to be pulled back manually.

Product Features

• Excellent control accuracy: Achieved through precise spindle guidance and parabolic cones.
• Exchangeable valve seats: Enable perfect coordination under the most demanding operating conditions.
• Robust actuator: Features optional stroke limitation and locking.
• Stainless steel valve body: Available with flange, threaded, clamp, or welded connections.

Technical Data

Property	Value
Design	Globe control valve
Nominal diameter	DN 10...DN 100, NPS 3/8...NPS 4
Flow direction	Flow to open (below seat)
Operating pressure	0 bar(g)...25 bar(g)
Nominal pressure	PN 25 (DIN EN 1333), Class 150 (DIN EN 1759)
Seat leakage	Leakage class II (metal), Leakage class VI for PTFE and PEEK (DIN EN 60534-4)
Kv value	0.1 m³/h...140 m³/h
Operating characteristic	Equal percentage (50:1 theoretical rangeability)
Medium temperature	-40 °C...+ 230 °C
Ambient temperature	-10 °C...+ 60 °C
Viscosity	Max. 600 mm²/s

Approvals and Conformities

• Explosion Protection: ATEX / IECEx (Category 2 device suitable for zone 1/21 and zone 2/22).
• Drinking Water: Suitable for use in drinking water applications (UBA).
• Foods and Beverages/Hygiene: FDA, USP, EC Regulation 1935/2004, China food GB Standards.

Materials

Element	Material
Cover	Polyamide (PA)
Handwheel	Polyphenylene sulphide (PPS)
Visual position indicator	Polyamide (PA)
Packing gland	PTFE V-rings (filled), with spring compensation
Stem	Stainless steel 1.4401 or 1.4404
Control cone	1.4571 (optionally hardened)
Seat seal (optional)	PTFE or PEEK
Valve body	Stainless steel 316L/CF3M

Operating Limits

Operating limits for seat seal

Tight sealing required	Leakage class	Medium temperature	Seat seal
No	II (metal seals)	-40 °C...+230 °C	Stainless steel
Yes	VI (soft seals)	-40 °C...+130 °C (recommended for ≤ +130 °C)	PTFE
Yes	VI (soft seals)	-10 °C...+230 °C (recommended for > +130 °C)	PEEK

Optional Variants

• High-temperature variant: Suitable for applications with steam, neutral gases and other heat transfer mediums up to +230 °C.
• Water variant: For applications with water up to +200 °C, a special configuration of the packing gland increases service life significantly.
• Low-temperature variant: Suitable for minimum medium temperatures down to -40 °C.

Pressure and Temperature Restriction (Derating)

Derating as per DIN EN 12516-1/PN25:

Temperature [°C]	Operating pressure [bar]
-10...+50	25
100	24.5
150	22.4
200	20.3
230	19

Function and Operation

Position Indicator

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

Note

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 and Characteristic

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.

Installation and Maintenance

Safety Instructions

• Risk of injury due to high pressure: Switch off the pressure before working on the device or system. Vent or drain the lines.
• Risk of crushing: Do not reach into the openings of the valve body.

Set Stroke Limit (Optional)

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. Move the valve to the desired maximally open position.
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 (Optional)

It is also an option to lock the handwheel to prevent unintentional or unauthorised operation of the valve. The locking pin has a bore (Ø 3.8) and can be secured against unauthorised use with a padlock.

Explosion Protection (ATEX) Guidelines

Explosion Hazard due to Electrostatic Charge

If a statically charged device or person suddenly discharges, there is a risk of explosion in potentially explosive areas.

• Take appropriate measures to ensure that static charge cannot build up in the Ex area.
• Only wipe the surface of the device gently with a damp or anti-static cloth.
• Ground the actuator and the valve body.

For media with varying conductivities, specific flow rate limits and grounding procedures must be strictly followed according to IEC 60079-32-1 to prevent electrostatic hazards.