The Bürkert 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
• Exchangeable valve seats enable perfect coordination under the most demanding operating conditions
• Robust actuator with optional stroke limitation and locking
• Stainless steel valve body with flange, socket, clamp or welded connection

Technical Data

Product properties	Description
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 (DIN EN 60534-4)	Leakage class II (metal), Leakage class VI for PTFE and PEEK
Kv value	0.1 m³/h...140 m³/h
Operating characteristic	Equal percentage
Operating medium	Steam, water, neutral gases, alcohols, oils, fuels, hydraulic fluids, salt solutions, alkalis, organic solvents
Medium temperature	-40 °C...+ 230 °C
Viscosity	Max. 600 mm²/s
Ambient temperature	-10 °C...+ 60 °C
Installation position	As required, preferably with actuator upright

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
Spindle guide	Stainless steel 1.4404 (316L), PTFE filled
Control cone	1.4571 (optionally hardened)
Seat seal (optional)	PTFE or PEEK
Valve body	Stainless steel 316L/CF3M

Approvals and Conformities

• Pressure Equipment Directive: 2014/68/EU
• Explosion Protection (Optional): ATEX / IECEx (Category 2 device suitable for zone 1/21 and zone 2/22). Ex h IIC T4...T2 Gb / Ex h IIIC T135 °C...T300 °C Db.
• Drinking Water: Suitable for use in drinking water applications (TrinkwasserV). PF39 variant suitable for hot water up to 85 °C.
• Foods and Beverages/Hygiene: FDA (Code of Federal Regulations), USP (United States Pharmacopeial Convention), EC Regulation 1935/2004, China food GB Standards.

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.

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

• Cone of equal percent for valve seat sizes 8 to 100
• Flow characteristic as per DIN EN 60534-2-4
• Theoretical rangeability (Kvs/Kvo): 50:1 for valve seat size 8 to 100

Stroke Limitation (Optional)

Both the minimum and the maximum position of the valve can be adjusted via an adjustment sleeve. The handwheel can be removed for this purpose.

Interlock / Lock Handwheel (Optional)

The valve can be secured against unintentional or unauthorized operation. For this purpose, a securing pin can be pressed down and turned. The locking pin has a hole (∅ 3.8) and can be secured with a padlock.

WARNING

The leakage class specified in the technical data cannot be guaranteed when the valve is locked in the closed position, depending on the operating and application conditions.

Operating Limits for Optional Variants

• High-temperature variant: Thanks to an adaption of the packing gland, this variant is 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. It is recommended for water temperatures starting at +85 °C.
• Drinking water variant: Wetted materials are tested in contact with the medium for suitability with drinking water up to +85 °C.
• Low-temperature variant: Suitable for minimum medium temperatures down to -40 °C.