BURKERT 344543 is a Type 2000 CLASSIC 2/2-way pneumatically operated angle seat valve designed for on/off fluid isolation in industrial processes. Featuring a cast stainless steel CF3M (316L) body and welded pipe ends conforming to ISO 4200, DIN EN ISO 1127, and DIN 11866 Series B (DN 25, outer diameter 33.7 mm, wall thickness 2.0 mm), the valve pairs a polyamide (PA) piston actuator with a self-adjusting PTFE V-ring packing gland.

Configured in Control Function A (normally closed by spring force) with fluid flow introduced below the valve seat, article 344543 delivers a flow coefficient Kv of 19 m³/h and maintains bubble-tight shut-off across operating pressures from 0 to 25 bar(g). The flow-below-seat design prevents liquid water hammer when cycling liquid and steam media. The unit requires 5.0 to 10.0 bar(g) pilot pressure, carries an IP67 enclosure rating, and supports Clean-in-Place (CIP) and Sterilization-in-Place (SIP) operations across medium temperatures from -10 °C to +185 °C.

Product Structure and Operating Principle

BURKERT 344543 consists of an angle seat valve body and a pneumatic piston actuator. The actuator housing is manufactured from glass-fiber-reinforced polyamide (PA), with a transparent polycarbonate cover that integrates a visual position indicator. The linear thrust generated by internal springs or pilot air transmits through a stainless steel spindle (1.4401/1.4404) to a swivel plate fitted with a PTFE seat seal disc.

Item	Component Description	Item	Component Description
1	Transparent cover with position indicator	7	Valve body (CF3M stainless steel)
2	Actuator cover	8	Body connection with wrench flats
3	Actuator housing (PA)	9	Spindle assembly
4	Relief / overflow bore	10	Lower pilot air port (G 1/4)
5	Welded pipe port (DN 25)	11	Upper pilot air port (G 1/4, plugged for CFA)
6	Flow direction marking

Control Function A and Flow Below Seat

Under Control Function A (SFA / CFA), internal preloaded springs press the spindle downward, keeping the PTFE seal seated against the orifice in the unpressurized rest position. When pilot air enters the lower control port (Port 10), the pneumatic piston compresses the spring stack and lifts the seal disc away from the seat.

Fluid flows under the seat (closing against the medium flow). Upstream process pressure acts against the underside of the swivel plate, which assists valve opening and eliminates the pressure surges associated with flow-over-seat shut-off in liquid systems.

Technical Data and Operating Limits

Parameter	Technical Specification
Valve Type	2000 CLASSIC
Article Number (MPN)	344543
Port Size (DN / NPS)	DN 25 / NPS 1
Connection Standard	ISO 4200 / DIN EN ISO 1127 / DIN 11866 Series B
Pipe Outer Diameter (OD) x Wall Thickness (WT)	33.7 mm x 2.0 mm (Inner Diameter: 29.7 mm)
Control Function	A (normally closed, NC)
Flow Direction	Below valve seat (flow to open)
Flow Factor Kv (Water at +20 °C, Δp = 1 bar)	19 m³/h
Seat Orifice Diameter	25 mm
Seat Leakage Rate	Leakage Rate A (DIN EN 12266-1, test medium air)
Working Medium Pressure	0 to 25 bar(g)
Nominal Pressure Class	PN 25 (DIN EN 1333) / Class 150 (DIN EN 1759)
Pilot Air Pressure	5.0 to 10.0 bar(g)
Pilot Air Connection	G 1/4 internal thread
Medium Temperature	-10 °C to +185 °C
Ambient Temperature	-10 °C to +60 °C
Storage Temperature	-20 °C to +65 °C
Permissible Fluid Viscosity	Max. 600 mm²/s
Enclosure Rating	IP67 (EN 60529 / IEC 60529)
Operating Media	Steam, water, neutral gases, alcohols, oils, fuels, hydraulic fluids, saline solutions, lyes, organic solvents
Control Medium	Neutral gases, instrument air

Pressure Derating by Medium Temperature

The maximum permissible working pressure decreases with rising medium temperature in accordance with international pressure vessel and valve body design standards.

Temperature [°C]	DIN EN 12516-1 PN25 Max Pressure [bar(g)]	ASME B16.34 Class 150 Max Pressure [bar(g)]
-10 to +38 / +50	25.0	19.0
100	24.5	16.2
150	22.4	14.8
185 (Max for PA/PTFE)	21.0	14.0
200	20.3	13.7
230	19.0	12.7

Ambient Temperature Limits

For Type 2000 valves equipped with polyamide (PA) actuators, continuous operation at the maximum medium temperature of +185 °C requires maintaining the ambient temperature within the rated limit of -10 °C to +60 °C.

Materials of Construction

Part Number	Component	Standard Material Specification
1	Transparent Cover	Polycarbonate (PC)
2	Pilot Air Ports	Stainless steel 1.4305
3	Actuator Housing	Polyamide (PA)
4	Piston Seal	NBR
5	Packing Gland Seal	PTFE V-rings (filled), spring compensated
6	Actuator Springs	Stainless steel 1.4310
7	Internal Tube	Stainless steel CF3M
8	Wiper Ring	PTFE (filled) / PEEK
9	Body Seal	Graphite (PTFE optional)
10	Valve Spindle	Stainless steel 1.4401 / 1.4404
11	Retaining Pin	Stainless steel 1.4401 / 1.4404
12	Seat Seal Disc	PTFE
13	Valve Body	Cast stainless steel CF3M (316L)
14	Swivel Plate (Disc Holder)	Stainless steel CF3M / 1.4404 / 1.4401

Dimensions and Pipe Standards

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

DN (Port Size)	ES [mm]	CS [mm]	LS [mm]	Ø DS [mm]	WS [mm]	Inner Diameter [mm]
DN 15	19	34	100	21.3	1.6	18.1
DN 20	20	39	115	26.9	1.6	23.7
DN 25 (344543)	26	43	130	33.7	2.0	29.7
DN 32	26	45	145	42.4	2.0	38.4
DN 40	26	49	160	48.3	2.0	44.3
DN 50	26	50	175	60.3	2.0	56.3

Actuator Dimensions for DN25 Angle Seat Body

Actuator Size	Ø A [mm]	B / H [mm]	K / M [mm]	P (Pilot Port)	BS / HS Overall Height [mm]
63 (E)	80	178	159	G 1/4	242
80 (F) (344543)	101	195	171	G 1/4	259

Actuator Dimension Tolerance

Dimensions B, H, K, M, HS, and BS represent maximum outer dimensions and can decrease by up to 6 mm depending on manufacturing tolerance and specific pipe standard.

Piping Installation and Actuator Handling

Mandatory Actuator Removal for Welded Housings

Prior to welding the valve body into the pipeline, the pneumatic actuator must be completely removed from the body. Welding heat conducted through the stainless steel casting will destroy the PTFE seat seal, spindle packing gland, and actuator piston seals.

Actuator Removal Procedure

1. Clamp the CF3M valve body firmly in a protective holding fixture.
2. Pressurize the pilot port: For Control Function A, apply 5.0 bar compressed air to the lower pilot air port (Port 10). This lifts the PTFE seat seal off the valve seat and prevents mechanical shearing of the seal disc during unscrewing.
3. Position an open-end wrench across the wrench flats on the body connection hexagon (never use a pipe wrench).
4. Unscrew the actuator assembly from the valve body.

Welding and Reassembly

1. Align the pipe connections stress-free and weld the CF3M body into the process line. Purge and clean pipes thoroughly of slag, swarf, and welding residue.
2. Inspect the graphite body gasket; replace if damaged.
3. Apply a thin coating of lubricating paste (Klüberpaste UH1 96-402) to the threads of the body connection.
4. Apply 5.0 bar compressed air to the lower pilot port to hold the seal disc in the retracted position.
5. Screw the actuator back into the body. Tighten to the specified torque:
   • DN 25 Tightening Torque: 60 Nm (+10 / -5 Nm).

Stepless 360° Actuator Orientation

To align the pilot air port with site pneumatic tubing, rotate the actuator relative to the body.

Rotation Direction Restriction

Apply 5.0 bar compressed air to the lower pilot port before turning the actuator. Hold the body connection hexagon with an open-end wrench and turn only the actuator hex part in the direction indicated on the illustration. Rotating in the opposite direction can unscrew the body joint and cause external fluid leakage.

Pneumatic Connection and Commissioning

• Connect pilot air line (G 1/4) to the lower pilot connection (Port 10).
• Feed only dry, clean, oil-free compressed air or neutral gas; avoid contaminated exhaust air.
• In aggressive or humid ambient atmospheres, run a pneumatic vent line from the upper exhaust port to a neutral zone.
• Controlled Startup Sequence: To avoid pressure shocks, establish pneumatic pilot supply first, cycle the valve open and closed once, and then slowly introduce the line fluid pressure.

Water Hammer Hazard with Liquid Media

Article 344543 is configured exclusively for flow below the valve seat. Never reverse installation flow direction over the seat when handling liquid media; rapid closing with fluid above the seat creates severe hydraulic shock waves (water hammer) that can rupture piping and valve bodies.

Maintenance, Visual Inspection, and Troubleshooting

Type 2000 actuators are maintenance-free under normal operating conditions. Regular preventive maintenance focuses on visual leak inspection across four critical points.

Inspection Point	Observed Fault	Remedial Action
1. Pipe Connection	External fluid leak at welded seam	Reseal or reweld pipe connection
2. Overflow / Relief Bore	Medium dripping from actuator base bore	Spindle packing gland worn; replace packing gland set
3. Valve Seat	Continuous flow when valve is de-energized	Seat seal worn or particulates trapped; flush line or replace valve set
4. Body Joint	External leakage between body and actuator	Replace graphite body seal and torque connection to 60 Nm

Troubleshooting Guide

Symptom	Probable Cause	Corrective Action
Actuator fails to switch	Pilot air pressure below 5.0 bar	Increase pilot pressure to 5.0–10.0 bar range
	Pilot air line connected to upper port	Reconnect pilot line to lower port (Port 10)
	Working medium pressure exceeds 25 bar	Verify line pressure against rating plate limits
Internal seat leakage	Debris or swarf trapped under seat	Disassemble and install upstream strainer (mesh < 1 mm)
	PTFE seat seal eroded or mechanically scored	Install new swivel plate / seal disc set
Fluid leaks at relief bore	Spindle V-ring pack worn	Replace packing gland seal assembly using dedicated tools

Service Kits, Assembly Tools, and Modular Accessories

Spare Part Kits and Maintenance Tools

• Process Valve Seal Set: Swivel plate with PTFE seal disc, retaining pin, and graphite body gasket.
• Packing Gland Kit: Pre-assembled PTFE V-rings with Belleville spring washer pack and wiper seal.
• Actuator Cover Assembly Wrench: For actuator size 80 mm (F) — Order no. 639171.
• Spindle Socket Wrench: WAF 21 mm for spindle disassembly — Order no. 683223.
• Packing Gland Installation Sleeve: For 10 mm spindle (Actuator 80 F, Dimension D = 8 mm) — Order no. 639168.
• Lubricating Paste: Klüberpaste UH1 96-402 (food-grade).

Modular Automation Add-ons

• Type 8697 Pneumatic Control Unit: Integrates direct mounting on CLASSIC actuators with mechanical or inductive position feedback switches, LED position display, IP65/IP67 ingress rating, and optional ATEX/IECEx intrinsic safety.
• Direct-Mount 3/2-Way Pilot Solenoid Valves: Banjo bolt mount directly onto G 1/4 pilot port.
  • Type 6014 (banjo G 1/4, 24 V DC: Order no. 334870; 230 V AC: Order no. 389550; cable plug Type 2518: Order no. 314812).
  • Type 7012 (banjo G 1/4, 24 V DC: Order no. 20077514; 230 V AC: Order no. 20077519).
• Type 2XXX Stroke Limiter: Restricts maximum or minimum stroke; available with top-mounted visual indicator.
• Complete Valve Systems: Can be combined with feedback units as Type 8801-YA CLASSIC automated process shut-off systems.