Bürkert 20120990 (Type 2961) is a manually operated 2-way globe control valve designed for excellent control accuracy. It consists of a manual actuator and a globe valve body with exchangeable seats made of high-quality stainless steel. The precise spindle guide enables reliable control even under demanding operating conditions. A soft PTFE seal guarantees reliable sealing, and the actuator is made of high-quality plastic suitable for use in demanding environments. It features a visual position indicator and is equipped with a DN 40 flange connection.

Product Features

• Excellent control accuracy: Achieved through precise spindle guiding and parabolic cones.
• Exchangeable valve seats: Enables perfect coordination under the most demanding operating conditions.
• Robust actuator: Made of high-quality plastic (PPS) with a visual position indicator.
• Stainless steel valve body: High-quality 316L/CF3M stainless steel with flange connection.
• Packing gland: Uses tried-and-tested V-seals with spring compensation, eliminating the need for manual retightening.

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	PTFE
12	Valve seat with O-ring	Stainless steel 1.4571, EPDM
13	Valve body	Stainless steel 316L/CF3M

Dimensions

Body with Flange Connection (DN 40)

INFO

Dimensions in mm, unless otherwise stated. Nominal diameter DIN EN 1092-1 PN 25 FTF 1 according to DIN EN 558-1.

DN	∅ DF	LF	∅ BF	AF	∅ D	A x α	∅ MF
40	150	200	110	18	18	4 × 90°	44.3

Performance Specifications

Flow Characteristics

• Flow characteristic according to DIN EN 60534-2-4.
• Theoretical rangeability (Kvs / Kvo): 50:1 for valve seat sizes 8 to 100.

Fluidic Data (DN 40)

Nominal diameter	Seat size	Handwheel ∅	Max. Operating Pressure	Kvs value
DN 40	40 mm	110 (M)	25 bar	24.0 m³/h

Operating Limits

In addition to the maximum operating pressures, the operating range of Bürkert process valves is limited by the nominal pressure according to the relevant standard.

Tight sealing required	Leakage class (DIN EN 60534-4)	Medium temperature	Seat seal
Yes	VI (soft seals)	-40 °C...+130 °C	PTFE

Product Design and Assembly

Position Indicator

When turning the handwheel counterclockwise, the reproducible stroke scale becomes visible between the attachment and the handwheel. The scale on the handwheel, together with the stroke scale, enables reproducible adjustment of the flow rate.

TIP

The scale on the handwheel determines the rotation position of the handwheel (50 positions). The reproducible stroke scale shows 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.

Installation and Safety

DANGER

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.

WARNING

Risk of crushing by mechanically powered parts Do not reach into the openings of the valve body. The upwards and downwards movement of the device means there is a risk of crushing.

Explosion Protection (ATEX / IECEx)

This device is approved for use in potentially explosive atmospheres (Zone 1/21 and Zone 2/22) as a Category 2 device (Ex h IIC T4...T2 Gb / Ex h IIIC T135°C...T300°C Db).

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 surfaces gently with a damp or anti-static cloth.
• Ground the actuator and the valve body.

Device Grounding: Conductive parts must be grounded independently. Install a grounding strap clip or grounding terminal as shown below and connect it to the grounding point to establish potential equalization.