BURKERT 20121061 (Type 2104) is an externally controlled diaphragm T-valve consisting of a pneumatically operated piston actuator, a diaphragm, and a T-valve body. The specific model 20121061 features a 2-inch (DN 50) weld end connection, a stainless steel body, a PTFE diaphragm with EPDM backing, and a PPS actuator. It operates as a 3/2-way valve with Control Function A (normally closed by spring force).

The proven and robust actuator with a stainless steel housing ensures reliable use in hygienic or aggressive ambient conditions. The flow-efficient valve bodies with minimal dead space enable high flow rates and a wide range of possible uses. The actuator has a compact, autoclavable design with gap-free seals, making it ideal for decentralised automation in the food, beverage, biotechnology, and pharmaceutical industries.

Technical Data

Property	Value
Nominal Diameter	DN 50 (2 inch)
Port Connection	Weld end (ASME BPE / DIN 11866 Series C)
Control Function	A - normally closed (NC)
Nominal Pressure	0 - 10 bar
Control Pressure	5 - 10 bar
Medium Temperature	-10 °C to +130 °C (Steam sterilisation max. +140 °C for 60 min)
Ambient Temperature	-10 °C to +60 °C (autoclavable)
Operating Medium	Neutral gases and liquids, highly purified, sterile, aggressive or abrasive mediums
Control Medium	Neutral gases, air

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	Diaphragm	PTFE with EPDM backing membrane
8	Valve body	Stainless steel

Approvals and Conformities

• FDA: The PTFE/EPDM diaphragm complies with the Code of Federal Regulations published by the FDA.
• USP: The PTFE/EPDM diaphragm is tested according to USP Class VI.
• EC Regulation 1935/2004: Suitable for use with food and beverages.
• 3-A Sanitary Standards: Complies with 3-A SSI (valid for variable code PE05).
• Explosion Protection: ATEX/IECEx variants available (II 2G Ex h IIC T4…T2 Gb / II 2D Ex h IIIC T135 °C…T300 °C Db).

Dimensions

Actuator

T-Body with Welded Connection

ASME BPE / DIN 11866 Series C (Selected Sizes)

Diaphragm size	Port 1 - Port 2 DN	∅D1	s1	∅D2	s2	A	B	C	E	F	G	H	I
50	50...50	50.80	1.65	50.80	1.65	188.0	115.8	145.0	30.0	71.0	42.0	6.5	30.0
50	65...50	63.50	1.65	50.80	1.65	188.0	122.1	157.0	30.0	85.0	50.0	14.5	30.0
50	80...50	76.20	1.65	50.80	1.65	188.0	128.5	169.0	30.0	98.0	56.0	20.5	30.0

(Note: Dimensions in mm. See full datasheet for all available sizes and configurations).

Installation

NOTICE: Damage to the diaphragm or the actuator

The diaphragm and actuator can be damaged when welding the valve body into the pipeline. In the case of devices with a welded connection, remove the actuator and diaphragm from the valve body before installation.

Installing the Actuator on the Valve Body (Control Function A)

1. Ensure the correct position of the compressor.
2. Pressurise the pilot air port 1 with compressed air (value as indicated on the type label): valve opens.
3. Place the actuator together with the diaphragm on the valve body.
4. Slightly tighten the body screws crosswise until the diaphragm rests between the valve body and the actuator. Do not fully tighten the screws yet.
5. Actuate the valve twice to position the diaphragm correctly.
6. Switch off the pilot pressure.
7. Without applying pressure, tighten the body screws in three stages (approx. 1/3, then 2/3 and then full tightening torque), in each case crosswise.

Tightening Torques for Body Connection

Diaphragm size	Tightening torques [Nm] (PTFE, advanced PTFE, GYLON®)
8	2.5
15	4
20	4.5
25	6
40	10
50	15
65	30
80	40
100	50

Networking and Combination

The Type 2104 valve can be combined with various Bürkert control units for decentralised automation, including:

• Type 8691 / 8695: Control heads for decentralised automation.
• Type 8690 / 8697: Pneumatic control units / position feedback.
• Type 8692 / 8694 / 8696: Digital electropneumatic positioners.
• Type 8693: Digital electropneumatic process controller.