BURKERT 325395 (Type 2103) is a pneumatically operated 2/2-way diaphragm valve configured for decentralised automation in hygienic, sterile, and demanding industrial fluid applications. Assembled as a complete valve unit under article number 325395, this configuration features a forged stainless steel valve body with DN 10 weld ends conforming to DIN 11850 Series 1 (12 mm outer diameter, 10 mm inner diameter, 1.0 mm wall thickness) and a body nominal size of 8 mm (diaphragm size 8). The valve is actuated by a pneumatic piston drive with a polyphenylene sulphide (PPS) core protected by a 1.4561 (316Ti) stainless steel outer casing in actuator size 50 mm (D). Operating in Control Function A (normally closed by spring force), the valve controls line pressure from 0 bar to 10 bar using a pilot pressure range of 5.5 bar to 7.0 bar applied via a 6 mm ELEMENT interface push-in connection.

Sealing is performed by a high-temperature EPDM diaphragm rated for continuous medium temperatures from -10 °C to +143 °C, with steam sterilisation tolerance up to +150 °C for 60 minutes. The valve has a flow coefficient Kv of 1.0 m³/h for water and meets nominal pressure rating PN 16 (Class 150). With low dead volume, gap-free seals, and smooth exterior contours, the valve satisfies CIP and SIP requirements. The factory package includes a manufacturer inspection certificate 3.1 and a factory certification 2.1 for the membrane.

Technical Specifications

Specification Parameter	Value / Range
Article Number	325395
Product Type	Type 2103 ELEMENT
Construction Status	Valve complete
Switching Positions	2/2-way
Control Function	CF A (normally closed by spring force, NC)
Valve Piloting	Pneumatic
Nominal Diameter (Port Size)	DN 10
Port 1 Connection Type	Weld end (DIN 11850 series 1 / R1)
Tube Dimensions	Inner Ø 10 mm, outer Ø 12 mm, wall thickness 1.0 mm
Diaphragm Size (Body Nominal Size)	8 mm (Diaphragm size 8)
Flow Capacity Kv (Water)	1.0 m³/h
Nominal Pressure Range	0.00 bar to 10.00 bar
Pressure Rating Standards	PN 16 (DIN EN 1333) / Class 150 (DIN EN 1759)
Control / Pilot Pressure Range	5.5 bar to 7.0 bar
Medium Temperature Range	-10 °C to +143 °C (steam sterilisation to +150 °C for 60 min)
Ambient Temperature Range	-10 °C to +55 °C (PPS actuator with push-in connector)
Valve Body Material	Forged stainless steel 1.4435 (BN2 / 316L)
Diaphragm Material	High-temperature EPDM (material code AD / E04)
Actuator Size	Ø 50 mm (D)
Actuator Housing Material	Polyphenylene sulphide (PPS)
Actuator Envelope / Casing	Stainless steel 1.4561 (316Ti)
Control Air Connection	ELEMENT interface, push-in fitting Ø 6 mm
Position Indicator	Without
Manual Override	No
Cleaning Capabilities	CIP capable, SIP capable
Quality Certifications	Test certificate 3.1, Membrane certification 2.1

Valve Construction and Materials

Type 2103 consists of a pneumatic piston actuator, an elastomer diaphragm, and a 2-way valve body. The piston mechanism transfers spring force or pneumatic thrust through a spindle to the compressor, pressing the diaphragm against the weir within the body.

Item No.	Component	Material
1	Ground terminal	Stainless steel 1.4301 / 1.4305 (ATEX/IECEx variant)
2	Transparent visual cap	Polysulfone (PSU)
3	Pilot air ports	Push-in connector PP (standard Ø 6 mm), G 1/8 stainless steel optional
4	Actuator core	Polyphenylene sulphide (PPS)
5	Actuator cover	Stainless steel 1.4561 (316Ti)
6	Piston seal	Fluoroelastomer (FKM)
7	Interface adapter	Polyphenylene sulphide (PPS standard), stainless steel 1.4308 optional
8	Diaphragm	EPDM high-temperature (AD)
9	Valve body	Forged stainless steel 1.4435 (BN2 / 316L)

Food and Pharmaceutical Compliance

Diaphragms manufactured from EPDM (AD) comply with the United States FDA 21 CFR regulations, pass USP Class VI biological tests, and meet European Regulation (EC) No 1935/2004 for materials contacting food and beverages. Optional configurations conform to 3-A Sanitary Standards (code PE05) and TA-Luft air quality directives (code PM01).

Operating Conditions and Pressure Ratings

Operating pressure ratings are determined by diaphragm material, body material, actuator size, and piloting pressure.

• Static tightness: The valve is closed with the diaphragm seated against the valve weir while maximum line pressure (up to 10 bar) is applied to one side of the seat. Zero leakage occurs across the weir.
• Dynamic tightness: Medium flows through the open valve with downstream line resistance creating pressure on both sides of the weir. The valve closes and establishes tight shut-off at line pressures up to 10 bar.

Diaphragm Size	Actuator Size	Pilot Pressure	Body Material	Max Static Pressure (EPDM)	Max Dynamic Pressure (EPDM)
8	50 (D)	3.7 to 10 bar (nom. 5.5–7.0 bar)	All materials	10 bar	10 bar

Permissible ambient temperature for the PPS actuator housing with push-in pneumatic connections is -10 °C to +55 °C (up to +60 °C depending on pneumatic piping type). Media temperatures must remain between -10 °C and +143 °C under standard operating conditions, with a temporary limit of +150 °C during clean-in-place steam sterilisation cycles of up to 60 minutes.

Dimensional Data

Actuator Dimensions

For diaphragm size 8 paired with actuator size 50 (D):

Diaphragm Size	Actuator Size Ø	Actuator Cover Outer Ø A	Height H	Height H+M
8	50 (D)	65 mm	119 mm	141 mm

Forged Body (VS) Welded Connection Dimensions

For diaphragm size 8, port connection DIN 11850 series 1 (tube dimensions 12.0 mm x 1.0 mm, port code SF40) and adjacent standards:

Diaphragm Size	Port DN	Pipe Standard	Outer Ø D1	Wall Thickness s	Length L	Dimension h	Dimension H	Product Key
8	10	DIN 11850 Series 1	12.0 mm	1.0 mm	90 mm	9.3 mm	18.8 mm	SF40
8	8	DIN 11850 Series 0	10.0 mm	1.0 mm	90 mm	5.7 mm	15.2 mm	SC42
8	10	DIN 11850 Series 2	13.0 mm	1.5 mm	90 mm	9.3 mm	18.8 mm	SD40
8	8	DIN EN ISO 1127	13.5 mm	1.6 mm	90 mm	9.3 mm	18.8 mm	SA40
8	10	DIN EN ISO 1127	17.2 mm	1.6 mm	90 mm	9.3 mm	18.8 mm	SA41

Installation and Self-Draining Guidelines

The valve may be installed in any orientation, preferably with the actuator facing upwards. When process piping requires complete emptying without pooling, the valve must be positioned according to specific self-draining criteria.

To establish self-draining performance:

1. The pipeline must maintain an inclination angle (β) matching plant piping design standards (such as ASME BPE).
2. The valve body must be rotated along its horizontal pipe axis by the specific self-draining angle (α).
3. The self-draining indicator marking stamped on the port connection must point upwards, and the angle must be verified using an angle gauge.
4. One of the relief bores in the diaphragm bonnet must point downwards at the lowest position to enable early leakage detection.

Port Connection Standard	Port Code	DN	Diaphragm Size	Pipe Dimension	Self-Draining Angle (α)
DIN 11850 Series 1	SF40	10	8	12.0 x 1.0 mm	24°
DIN 11850 Series 2	SD40	10	8	13.0 x 1.5 mm	24°
DIN 11850 Series 0	SC42	8	8	10.0 x 1.0 mm	39°
DIN EN ISO 1127	SA41	10	8	17.2 x 1.6 mm	13°

Actuator Assembly and Tightening Torques

Welding Precautions

Direct welding heat damages elastomer diaphragms and polymer actuator parts. For valves with welded port connections, the actuator and diaphragm must be unbolted and removed from the valve body before the body is welded into the pipe run.

Actuator Removal Procedure

1. For Control Function A, apply pilot pressure to pilot air port 1 (value per type label, 5.5 to 7.0 bar) to lift the diaphragm off the valve seat.
2. Loosen the body fasteners crosswise.
3. Lift the actuator assembly and diaphragm away from the valve body.
4. Weld the valve body into the pipeline, allow the joint to cool, and thoroughly clean weld residues.

Actuator Installation and Fastener Torques

1. Confirm the diaphragm is attached to the compressor. Diaphragm size 8 uses a push-in button fastening system; rotate slightly to seat the button.
2. Pressurise pilot air port 1 with compressed air (5.5 to 7.0 bar) to retract the spindle and compressor (valve opens).
3. Place the actuator with the diaphragm onto the valve body.
4. Screw in the body screws hand-tight crosswise until the diaphragm is seated evenly.
5. Actuate the valve twice using pilot air to seat the elastomer.
6. Vent the pilot pressure.
7. In a depressurised state, tighten the body screws crosswise in three progressive stages (approx. 1/3, 2/3, and full torque) to the specified values.

Diaphragm Size	Forged Body Torque: EPDM, FKM	Forged Body Torque: PTFE, GYLON®	Tube Body Torque: EPDM, FKM	Tube Body Torque: PTFE, GYLON®
8	2.0 Nm (+10%)	2.5 Nm (+10%)	2.0 Nm (+10%)	2.5 Nm (+10%)
15	3.5 Nm (+10%)	4.0 Nm (+10%)	3.5 Nm (+10%)	4.0 Nm (+10%)
20	4.0 Nm (+10%)	4.5 Nm (+10%)	4.0 Nm (+10%)	4.5 Nm (+10%)
25	5.0 Nm (+10%)	6.0 Nm (+10%)	7.0 Nm (+10%)	8.0 Nm (+10%)

Automation and Decentralised Control Options

Article 325395 is supplied without an electrical position indicator. The modular ELEMENT actuator interface permits direct retrofitting of decentralized Bürkert automation units:

• Type 8695 Control Head: Designed for actuator size 50 mm (D), featuring contact-free inductive position sensing, teach-in end position adjustment, integrated pilot valve with manual override, high-visibility colored status LEDs, and communication options via AS-Interface, IO-Link, or büS.
• Type 8697 Pneumatic Control Unit: Designed for actuator size 50 mm (D), incorporating mechanical or inductive proximity switches for discrete limit detection and an optical position indicator.
• Type 8696 Electropneumatic Positioner: Digital compact positioner engineered for integrated attachment to actuator size 50 mm (D) for continuous modulating service.

All ELEMENT control units mount without external tubing, routing pilot air internally to prevent environmental ingress and maintain IP65/67 protection.

Maintenance, Inspection, and Spare Parts

The pneumatic actuator mechanism is maintenance-free under recommended operating parameters. Regular inspection is limited to seals and the diaphragm.

• Retightening: Body screws must be checked and retightened crosswise to the specified torque (2.0 Nm) after the first steam sterilisation cycle.
• Inspection Interval: Inspect the diaphragm for physical wear, swelling, or deformation at least every 100,000 switching cycles. More frequent checks are required with abrasive media.
• Leakage Monitoring: The relief bore on the diaphragm bonnet must be visually checked periodically. Any fluid discharge indicates diaphragm failure and requires immediate replacement.

Diaphragm Size	Diaphragm Material	Material Code	Spare Part Order Number
8	EPDM	E04	688421
8	FKM	F01	677684
8	PTFE / EPDM	L11	20093068
8	Advanced PTFE	L12	20093078
8	GYLON® / EPDM	L08	693175

Storage Recommendations

Elastomer spare parts should be stored in airtight packaging at temperatures between +5 °C and +25 °C, shielded from direct sunlight, ozone sources, and relative humidity exceeding 65%. Under these conditions, the maximum storage shelf life for EPDM diaphragms is 7 years with an anticipated operational service life of up to 3 years.