BURKERT 20082562 (Type 2961) is a manually operated 2-way globe control valve engineered for precise continuous flow control of liquids, steam, and neutral gases under demanding process conditions. Configured under article number 20082562, this assembly integrates a PPS manual actuator with an optical stroke scale and a 316L/CF3M stainless steel globe body featuring DN 10 (NPS 3/8) welded ends according to DIN EN ISO 1127, ISO 4200, and DIN 11866 Series B (pipe dimensions 17.2 x 1.6 mm). The valve is fitted with an exchangeable 6 mm stainless steel seat and an equal percentage parabolic control cone providing a theoretical rangeability of 50:1, rated for a nominal flow coefficient Kvs of 1.25 m³/h (Cv 1.5 gpm) and leakage class VI per DIN EN 60534-4 via a soft PTFE seat seal.

Type 2961 features a spindle guide made of PTFE-filled 316L stainless steel and a self-adjusting packing gland with filled PTFE V-rings and spring compensation, eliminating the need for manual gland retightening. The valve closes against the medium flow (flow below seat) and operates across an operating pressure range of 0 to 25 bar(g) with a medium temperature capability of -10 °C to +130 °C for the PTFE seat variant.

Technical Data Summary

Parameter	Technical Specification (Article 20082562)
Valve Type	Type 2961 2-way globe control valve
Article Number	20082562
Port Nominal Size	DN 10 (NPS 3/8)
Port Connection Type	Welded ends
Connection Standard	DIN EN ISO 1127 / ISO 4200 / DIN 11866 Series B
Pipe Outer Diameter x Wall Thickness	17.2 x 1.6 mm
Valve Body Material	Stainless steel 316L / CF3M
Actuator Material	Polyphenylene sulphide (PPS)
Seat Diameter	6 mm (1/4")
Seat Seal Material	PTFE (Polytetrafluoroethylene)
Flow Direction	Below seat (flow to open)
Flow Characteristic	Equal percentage parabolic cone (50:1)
Rated Flow Coefficient Kvs	1.25 m³/h (Cv = 1.5 gpm)
Seat Leakage Class	Class VI according to DIN EN 60534-4:2006
Nominal Pressure Class	PN 25 (DIN EN 1333), Class 150 (DIN EN 1759)
Operating Pressure Range	0 to 25 bar(g)
Medium Temperature Range	-10 °C to +130 °C
Ambient Temperature Range	-10 °C to +60 °C
Maximum Medium Viscosity	600 mm²/s
Handwheel Size / Diameter	Size S / 45 mm
Handwheel Travel Pitch	1.25 mm per revolution
Actuator Interface	Spindle D10
Body Screwing Tightening Torque	45 Nm (±3 Nm)

Material Specifications and Cross-Sectional Design

The mechanical construction of Type 2961 uses materials selected for chemical resistance and mechanical stability under high pressure and thermal cycling:

Item 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	Stainless steel 1.4571 (optionally hardened)
11	Seat seal	PTFE (or optional PEEK)
12	Valve seat with O-ring	Stainless steel 1.4571, EPDM
13	Valve body	Stainless steel 316L / CF3M

Fluidic Data and Flow Characteristics

Type 2961 control valves conform to DIN EN 60534-2-4 flow characteristics. The parabolic plug geometry generates an equal percentage characteristic with a theoretical rangeability (Kvs/Kv0) of 50:1. For seat diameters up to 10 mm, the KvR value is defined at 10% of stroke, representing the smallest Kv value at which the tilt tolerance according to DIN EN 60534-2-4 is maintained.

Intermediate Kv Values Across Stroke (DN 10, Seat Size 6 mm)

For article 20082562 with DN 10 port connection and 6 mm seat orifice, flow rates measured with water per DIN EN 60534-2-4 across opening stroke increments are structured as follows:

Stroke (%)	Kv Value [m³/h]	Rangeability	Max Operating Pressure [bar(g)]	Seat Leakage Class
5%	0.005	50:1	25	Class VI (PTFE)
10%	0.007	50:1	25	Class VI (PTFE)
20%	0.011	50:1	25	Class VI (PTFE)
30%	0.045	50:1	25	Class VI (PTFE)
40%	0.085	50:1	25	Class VI (PTFE)
50%	0.16	50:1	25	Class VI (PTFE)
60%	0.26	50:1	25	Class VI (PTFE)
70%	0.41	50:1	25	Class VI (PTFE)
80%	0.65	50:1	25	Class VI (PTFE)
90%	1.10	50:1	25	Class VI (PTFE)
100%	1.25	50:1	25	Class VI (PTFE)
Kvs	1.25	50:1	25	Class VI (PTFE)

Seat Seal Operating Limits

Tight Sealing Required	Leakage Class (DIN EN 60534-4)	Medium Temperature Range	Seat Seal Material
No (Additional shut-off valve recommended)	Class II (0.5% nominal flow permissible)	-40 °C to +230 °C	Stainless steel (metallic seal)
Yes (Tight shut-off achieved)	Class VI (soft seal)	-40 °C to +130 °C (recommended for ≤ +130 °C)	PTFE (Fitted in 20082562)
Yes (Tight shut-off achieved)	Class VI (soft seal)	-10 °C to +230 °C (recommended for > +130 °C)	PEEK

Flow Direction and Seating

The valve must be installed with flow entering beneath the seat (flow to open). Closing the valve moves the parabolic plug downward against the oncoming medium flow, ensuring stable positioning without flutter.

Pressure and Temperature Operating Limits

Maximum allowable working pressures are governed by temperature derating curves in accordance with DIN EN 12516-1 (PN25), ASME B16.34 (Class 150), and JIS B 2220 (10K).

Pressure Derating According to DIN EN 12516-1 (PN 25)

Temperature [°C]	Maximum Permissible Operating Pressure [bar]
-10 to +50	25.0
+100	24.5
+150	22.4
+200	20.3
+230	19.0

Application-Specific Variants Supported by Type 2961

• High-temperature variant: Adapted packing gland configuration suitable for steam, neutral gases, and thermal media up to +230 °C.
• Water variant: Special packing gland configuration enhancing service life for water applications up to +200 °C; recommended starting at +85 °C.
• Drinking water variant: Wetted materials evaluated according to UBA assessment principles (TrinkwasserV) for hot water up to +85 °C (PF39).
• Low-temperature variant: Engineered for minimum medium temperatures down to -40 °C.

Dimensions and Mechanical Specifications

Welded Body Dimensions (DIN EN ISO 1127 / ISO 4200 / DIN 11866 Series B)

Nominal Diameter DN	External Pipe Diameter (∅ DS) [mm]	Wall Thickness (WS) [mm]	Body Face-to-Face Length (LS) [mm]	Weld End Extension (ES) [mm]
10 (Article 20082562)	17.2	1.6	90	20
15	21.3	1.6	90	20
20	26.9	1.6	100	20
25	33.7	2.0	130	26

Manual Actuator Dimensions

Handwheel Size	Handwheel Diameter ∅ [mm]	Height H1 [mm]	Height H2 (with Lock) [mm]	Slope per Revolution [mm]	Applicable Pipe Sizes
S (Small)	45	217	224	1.25	DN 10 to DN 25
M (Medium)	110	296 to 307	303 to 313	1.75	DN 32 to DN 50
L (Large)	160	361 to 379	368 to 385	2.00	DN 65 to DN 100

Actuator Operation, Stroke Limiting, and Interlock

Turning the handwheel counterclockwise lifts the spindle and opens the valve port, while clockwise rotation closes it. The manual actuator integrates two visual indication elements:

1. A circumferential 50-division scale on the handwheel indicating rotational position.
2. A vertical reproducible stroke scale positioned between the actuator housing and the bottom edge of the handwheel.

Stroke Limitation Adjustment

Both minimum and maximum valve openings can be mechanically bounded via the internal adjustment sleeve:

1. Rotate handwheel clockwise to fully close the valve.
2. Loosen the handwheel fastening screw (AF 2 hexagon socket) and remove the handwheel.
3. Screw the adjusting sleeve clockwise until it stops against its seat to set the minimum stroke limit.
4. Reinstall handwheel, aligning the square stem profile and hexagon sleeve head with the handwheel hub.
5. Rotate handwheel counterclockwise to the desired maximum travel position.
6. Remove handwheel again, pull adjusting sleeve upward, and rotate counterclockwise until it stops to set the maximum stroke limit.
7. Reinstall handwheel and torque the fastening screw to 0.9 Nm.

Handwheel Lock Mechanism

The handwheel locking device secures the valve against accidental or unauthorized operation:

• Handwheel size S features 12 locking detents per revolution (every 30° of turn, corresponding to 0.10 mm of stroke travel).
• The locking pin is engaged by pushing down and rotating 180° until fully seated.
• A through-hole (3.8 mm diameter) in the locking pin accommodates a padlock (available under accessory article 93719475).

Tight Sealing under Interlock

Leakage class VI tightness cannot be guaranteed when the valve is locked in the closed position using the interlock pin, due to variations in thermal expansion and operational seated pressure.

Installation, Welding, and Maintenance Procedures

Welded Body Installation

For valves with welded ends, the actuator must be disassembled from the body before welding into the pipeline to prevent thermal damage to internal PTFE components and actuator plastics.

Disassembly and Reassembly for Welding

1. Rotate the handwheel counterclockwise approximately two full turns to lift the plug off the seat.
2. Engage an open-end wrench on the body connection wrench flats and unscrew the actuator from the valve body.
3. Weld or orbitally join the 316L valve body into the pipeline system.
4. Verify pipeline cleanliness and flush out weld spatter, slag, and debris.
5. Inspect the graphite housing seal (Item 9) and replace if damaged.
6. Lubricate the external threads of the body connection with an approved lubricant (such as Klüberpaste UH1 96-402).
7. Screw the actuator back into the body and tighten to 45 Nm (±3 Nm) for DN 10.

Inspection and Troubleshooting

Under normal operation according to manual specifications, the PPS actuator is maintenance-free. Annual visual inspection is recommended, including checking the actuator relief bore for fluid discharge indicative of packing gland wear.

Fault	Possible Cause	Corrective Action
Valve does not seal tightly	Particulate entrapment between seat and plug	Install upstream strainer or dirt trap
	Valve seat seal worn or damaged	Replace seat / closure member
	Reverse flow orientation	Reorient valve so flow enters below seat
	Operating pressure exceeds limit	Verify line pressure against type label limits
Fluid escaping through relief bore	Packing gland V-rings worn	Replace packing gland seal kit

Standards, Approvals, and Safety Options

Type 2961 conforms to the European Pressure Equipment Directive 2014/68/EU. Wetted materials are available with FDA compliance (Code of Federal Regulations, variable codes PL02/PL03), USP Class VI biocompatibility (variable code PL04), Regulation (EC) No 1935/2004 (codes PL01/PL02), and China food GB standards (variable code PL10).

Supplementary Ex Protection Requirements (PX51)

When ordered with variable code PX51, Type 2961 valves comply with ATEX and IECEx mechanical explosion protection directives:

• ATEX: 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: IECEx EPS 18.0007X (Ex h IIC T4...T2 Gb / Ex h IIIC T135 °C...T300 °C Db)
• Temperature classes: T4 (max surface 135 °C, medium up to 125 °C), T3 (max surface 200 °C, medium up to 185 °C), T2 (max surface 300 °C, medium up to 285 °C).
• Equipotential bonding: Valve body and conductive metal parts must be grounded to the pipeline system using grounding straps or earthing terminals.