Burkert 350272 (Type 2031) is an externally controlled 2/2-way diaphragm valve with a pneumatic piston actuator, an EPDM diaphragm, and a forged stainless steel valve body. Designed for ultra-pure, sterile, and aggressive media, it operates in control function A (normally closed by spring force) across an operating pressure range of 0 to 10 bar. The unit features an ASME BPE / DIN 11866 Series C weld connection in size 3/8 inch (DN 10, pipe dimensions 9.53 x 0.89 mm) and provides a water flow factor (Kv value) of 1.6 m³/h.

Manufactured with a polyphenylene sulphide (PPS) actuator housing in size 40 mm (actuator code C), Burkert 350272 is autoclavable and withstands ambient temperatures up to +140 °C. The flow-optimized forged body (type VS) has minimal dead space and meets strict hygienic requirements, featuring full CIP and SIP cleanability with steam sterilization resistance up to +150 °C for 60 minutes.

Valve Construction and Operating Principle

Burkert 350272 uses control function A (CF A). In the de-energized rest position, integrated compression springs generate the closing force on the piston actuator. A spindle transmits this closing force directly to the compressor, pressing the elastomeric diaphragm tightly against the weir in the valve body to shut off fluid flow in both directions.

Applying pilot pressure (5.0 to 7.0 bar) to the lower pilot air port compresses the spring pack, lifting the piston, spindle, compressor, and diaphragm away from the weir to open the flow path. When the pilot port is vented, spring force returns the diaphragm to its closed position.

Position	Component	Description
1	Transparent cap	Visual position indicator cap made of polysulfone (PSU)
2	Actuator cover	Polyphenylene sulphide (PPS) housing cover
3	Upper pilot air port	G 1/8 port (used for CF B and CF I)
4	Lower pilot air port	G 1/8 port for CF A (applies pilot pressure to open the valve)
5	Diaphragm bonnet	Intermediate housing interface
6	Diaphragm	High-temperature EPDM sealing diaphragm (size 8)
7	Body screws	Fasteners securing actuator assembly to valve body
8	Port connection	ASME BPE 3/8" weld ends
9	Valve body	Forged stainless steel weir body (1.4435 / 316L)

Technical Specifications

Parameter	Specification
Burkert Article Number	350272
Valve Type	2031 CLASSIC
Configuration	2/2-way on/off valve
Control Function	CF A: Normally closed by spring force
Actuator Size	Ø 40 mm (Actuator C)
Actuator Housing Material	Polyphenylene sulphide (PPS)
Body Construction	Forged valve body (VS)
Body Material	Stainless steel 1.4435 (BN2 / 316L)
Diaphragm Size (DS)	8 mm
Diaphragm Material	EPDM high-temperature (Code AD / E04)
Piston Seal Material	Fluor rubber (FKM)
Connection Standard	ASME BPE / DIN 11866 Series C (Port Code SA91)
Connection Size	DN 10 (3/8")
Pipe Dimensions	Outer Ø 9.53 mm, Inner Ø 7.75 mm, Wall thickness 0.89 mm (0.035")
Flow Rate (Kv water at +20 °C)	1.6 m³/h
Operating Pressure Range	0 to 10 bar (static / dynamic)
Pilot Pressure Range	5.0 to 7.0 bar
Nominal Pressure Class	PN 16 / Class 150
Medium Temperature	-10 °C to +143 °C (steam sterilization up to +150 °C for 60 min)
Ambient Temperature	+5 °C to +140 °C
Pilot Air Connection	G 1/8 internal thread
Pilot Control Medium	Neutral gases, filtered compressed air
Cleaning Capabilities	CIP capable, SIP capable
Standard Compliance	Manufacturer test certificate 3.1, Membrane factory certification 2.1, FDA, USP Class VI, EC 1935/2004

Materials of Construction

Item	Element	Material
1	Transparent cap	Polysulfone (PSU)
2	Cover	Polyphenylene sulphide (PPS)
3	Pilot air ports	Stainless steel 1.4305
4	Piston seal	Fluor rubber (FKM)
5	Socket	Sintered metal
6	Interface / Bonnet	Polyphenylene sulphide (PPS)
7	Diaphragm	EPDM (AD) high-temperature
8	Valve body	Forged stainless steel 1.4435 (BN2 / 316L)

Dimensions and ASME BPE Connection

Actuator Dimensions (Size 40 / Code C)

• Diameter Ø A: 53 mm
• Bonnet clearance C: 34 mm
• Pilot connection K: G 1/8"
• Total actuator height H: 89 mm (113 mm when equipped with MT85 block interface; 185 mm with Type 8697 control head)

Forged Body (VS) Weld End Dimensions (ASME BPE / DIN 11866 Series C)

Diaphragm Size	Port Connection DN	Outer Ø D1 [mm]	Wall Thickness s [mm]	Body Length L [mm]	Height h [mm]	Body Height H [mm]	Product Key
6	1/4"	6.35	0.89	78	5.7	15.2	SA90
6	3/8"	9.53	0.89	89	5.7	15.2	SA91
6	1/2"	12.70	1.65	89	9.3	18.8	SA92
8 (Model 350272)	1/4"	6.35	0.89	78	5.7	15.2	SA90
8 (Model 350272)	3/8"	9.53	0.89	89	5.7	15.2	SA91
8 (Model 350272)	1/2"	12.70	1.65	89	9.3	18.8	SA92
15	1/2"	12.70	1.65	108	8.15	19.85	SA92
15	3/4"	19.05	1.65	108	12.05	23.75	SA93
20	3/4"	19.05	1.65	117	16.0	30.3	SA93
25	1"	25.40	1.65	127	19.0	37.0	SODF

Flow Rate Characteristics

Flow rate values correspond to Kv water flow in m³/h measured at +20 °C with 4 bar valve inlet pressure and 3 bar valve outlet pressure for elastomeric diaphragms.

Diaphragm Size	Port DN [mm]	Port DN [inch]	DIN EN ISO 1127 (Series B)	DIN 11850-2 (Series A)	ASME BPE (Series C)	BS 4825
6	8	1/4"	2.2	-	0.7	-
6	10	3/8"	-	2.0	1.6	-
8	8	1/4"	1.5	-	0.7	0.5
8 (Model 350272)	10	3/8"	1.5	1.5	1.6	1.4
8	15	1/2"	-	-	1.9	-
15	15	1/2"	6.5	6.5	3.1	3.7
20	20	3/4"	12.5	12.4	8.4	8.9
25	25	1"	18.0	20.0	15.5	15.5

Installation and Self-Draining Guidelines

Burkert 350272 can be mounted in any orientation, but positioning the pneumatic actuator upright is recommended. For complete hygienic gravity draining, the installation must adhere to specific alignment angles:

• Pipeline inclination angle (β): maintain a continuous line slope between 1° and 5°.
• Valve self-draining angle (α): set with a dedicated angle meter according to the body dimensions. The cast or etched laser alignment marking on the port connection must face upwards.

Self-Draining Angle for SA91

For forged valve bodies with ASME BPE / DIN 11866 Series C weld ends, port code SA91 (DN 10 / 3/8", pipe dimensions 9.53 x 0.89 mm, diaphragm size 8), the determined self-draining angle α is exactly 39°.

Welding Precaution

Before welding the forged body into the pipeline, the pneumatic actuator and diaphragm must be completely removed from the body. Thermal exposure during welding will permanently destroy the EPDM diaphragm and internal actuator seals. Reinstall the actuator assembly only after the weld seams have cooled down and the piping has been flushed.

Tightening Torques and Assembly

Fastening body screws requires crosswise, stepped tightening to ensure uniform perimeter compression of the EPDM diaphragm.

Diaphragm Size	Forged Body (VS), Cast (VG), Plastic [Nm] (EPDM / FKM)	Forged Body (VS), Cast (VG), Plastic [Nm] (PTFE / GYLON®)	Tube Body (VP) [Nm] (EPDM / FKM)	Tube Body (VP) [Nm] (PTFE / GYLON®)
6	1.1	1.1	-	-
8 (Model 350272)	2.0	2.5	2.0	2.5
15	3.5	4.0	3.5	4.0
20	4.0	4.5	4.0	4.5
25	5.0	6.0	7.0	8.0
32	6.0	8.0	8.0	10.0
40	8.0	10.0	12.0	15.0
50	12.0	15.0	15.0	20.0
65	20.0	30.0	20.0	30.0

All specified tightening torque values have an engineering tolerance of +10%.

Installation Procedure for Control Function A

1. Connect compressed air (5.0 to 7.0 bar) to the lower pilot air port to retract the spindle and open the valve mechanism.
2. Place the actuator with the attached diaphragm onto the valve body.
3. Finger-tighten the body screws crosswise until the diaphragm rests evenly between the bonnet and body.
4. Cycle the valve twice using pilot pressure to seat the diaphragm correctly.
5. Disconnect the pilot pressure.
6. Tighten the body screws in three crosswise stages (1/3 torque, 2/3 torque, and full 2.0 Nm torque) without pilot pressure applied.

Maintenance, Diaphragm Replacement, and Spare Parts

The pneumatic actuator is maintenance-free under normal operating conditions. Regular maintenance focuses on inspection of wearing parts (seals and diaphragm):

• Check the bonnet relief bore regularly for medium leakage. Any leakage indicates diaphragm wear.
• Retighten the body screws crosswise after the initial steam sterilization cycle.
• Inspect the diaphragm for mechanical or chemical wear after a maximum of 100,000 switching cycles.

Diaphragm Replacement for Diaphragm Size 8

Diaphragm size 8 uses a buttoned fastening mechanism. To replace the diaphragm on CF A valves:

1. Apply pilot pressure to the lower pilot connection to separate the diaphragm from the body seat without tearing.
2. Loosen the body screws crosswise and lift the actuator off the body.
3. Pull the old EPDM diaphragm off the compressor pin.
4. Button the new EPDM diaphragm onto the compressor with a slight twist until fully seated. Align the diaphragm tab perpendicular to the pipe flow direction.
5. Reassemble the actuator to the body and torque screws crosswise in three stages to 2.0 Nm.

Spare Parts and Accessories Ordering Data

Item	Description	Actuator / DS	Order Number
Seal set	Complete internal actuator seal set (FKM / NBR)	PPS Actuator 40 (C) / DS 8	011465
Replacement diaphragm	EPDM high-temperature diaphragm (AD / material code E04)	Diaphragm size 8	688421
Actuator wrench	Service wrench for actuator housing cover	Actuator size 40 (C)	639175