BURKERT 321073 (Type 2103) is an externally controlled 2/2-way diaphragm valve consisting of a pneumatically operated PPS piston actuator, an EPDM high-temperature diaphragm, and a stainless steel cast valve body. The flow-efficient valve body with little dead space enables high flow rates and a wide range of possible uses. It features a DN 25 weld end connection and operates as normally closed (Control Function A). The actuator has a compact design with gap-free seals, ensuring reliable use in demanding ambient conditions.

No.	Element	Description
1	Transparent cap with position	-
2	Pilot air port 1	For CF A, CF B and CF I
3	Pilot air port 2	For CF I, exhaust port for CF A and CF B
4	Actuator cover	-
5	Actuator housing	-
6	Diaphragm bonnet	-
7	Diaphragm	-
8	Body screw	-
9	Valve body	-
10	Port connection	-

Materials

No.	Element	Material
1	Ground terminal	Stainless steel 1.4301/1.4305 (only for ATEX/IECEx variant)
2	Transparent cap	Polysulfone PSU
3	Pilot air ports	Push-in connector PP (standard), Thread G 1/8" stainless steel 1.4305
4	Actuator	Polyphenylene sulphide PPS
5	Cover	Stainless steel 1.4561 (316Ti)
6	Piston seal	FKM
7	Interface	Polyphenylene sulphide PPS (standard)
8	Diaphragm	EPDM (AD)
9	Valve body	Stainless steel precision casting 1.4435 / 316L

Dimensions

Cast Valve Body (VG) with Welded Connection(Dimensions in mm, unless otherwise stated)

Diaphragm size	Port connection DN	∅ D1	s	L	h	H
25	25	29	1.5	129	20	39

Note: Dimensions correspond to DIN 11850-2 / DIN 11866 series A / DIN EN 10357 series A.

Performance Specifications

Flow CharacteristicsKv value [m³/h]: Measurement with water according to DIN EN 60534-2-4

Diaphragm size	Port connection DN	Actuator size ∅	Diaphragm material	Kvs value [m³/h]
25	25	70 (M), 90 (N)	EPDM	14.6

Installation & Safety

Danger due to escaping medium

If the diaphragm is worn, medium can escape and seriously injure people. The relief bore must be regularly inspected for any medium leakages. If medium is leaking from the relief bore, replace the diaphragm.

Welding the valve body into the pipeline

The diaphragm and actuator can be damaged when welding the valve body into the pipeline. Remove the actuator and diaphragm from the valve body before installation. After welding the surface of the valve body, smooth by sanding if necessary and clean carefully before reinstalling the actuator.