BURKERT 348208 Type 2031 is an externally controlled 2/2-way diaphragm valve with a pneumatic piston actuator and diaphragm seal. It uses neutral gases or air to control the flow of media. The proven and robust PA (Polyamide) actuator combined with a flow-optimised stainless steel valve body ensures reliable operation in hygienic or aggressive environments. This specific model features a DN 20 weld end connection, an EPDM high-temperature diaphragm, and operates with Control Function A (normally closed by spring force).

Product Design

Component	Description
1	Transparent cap with position indicator
2	Actuator cover
3	Upper pilot air port for CF A and CF I
4	Lower pilot air port for CF A and CF I
5	Diaphragm bonnet
6	Diaphragm
7	Body screw
8	Port connection
9	Valve body

Control Functions

Depending on the control function, spring force (CF A) or pneumatic pilot pressure (CF B, CF I) generates the closing force. A spindle connected to the actuator piston transfers the force to the compressor, which presses the diaphragm against the weir in the valve body.

• Control function A (CF A): Pneumatically operated 2/2-way on/off valve. Bidirectional. Closed by spring force in rest position.
• Control function B (CF B): Pneumatically operated 2/2-way on/off valve. Bidirectional. Opened by spring force in rest position.
• Control function I (CF I): Pneumatically operated 2/2-way on/off valve on both sides. Bidirectional. Switching position dependent on external control unit.

Technical Data

Permissible Temperatures

Ambient Temperature:

• PA Actuator (≤125 H): -10 °C to +60 °C
• PA Actuator (≥175 K): -10 °C to +50 °C

Medium Temperature for Diaphragms: The specified medium temperatures only apply to media that do not attack the diaphragm materials or cause it to swell up. Do not use the diaphragms as a steam shut-off element.

• EPDM (AD): -10 °C to +143 °C (Steam sterilisation max. +150 °C for 60 min)
• FKM (FF): 0 °C to +130 °C (No steam, dry heat max +150 °C for 60 min)
• PTFE (EA): -10 °C to +130 °C (Steam sterilisation max. +140 °C for 60 min)

Operating Pressure

Maximum permissible operating pressure for control function A (Stainless Steel Body):

Diaphragm size	Actuator size	Pilot pressure [bar]	Max. Dynamic Pressure (EPDM) [bar]	Max. Static Pressure (EPDM) [bar]
15	50 (D)	5.0–7	8.5	10
15	63 (E)	5.0–7	10	10
20	63 (E)	5.5–7	10	10
20	80 (F)	5.0–7	10	10
25	80 (F)	5.5–7	10	10
32	100 (G)	5.5–7	10	10

Installation

Ensuring Self-Draining

The installer and the operator are responsible for ensuring self-draining. The following points must be observed for optimum self-draining:

1. Inclination angle of the pipeline: It should correspond to the inclination angle of the pipeline. For pipelines, the inclination angles specified in the valid ASME BPE standard are recommended.
2. Self-draining angle for valve body: The self-draining angle (α) depends on the size of the valve body and the inner diameter of the port connection. The marking for self-draining angles on the port connection serves as a guide and must point upwards.

Welding the Valve Body into the Pipeline

CAUTION: Damage to the diaphragm or the actuator

The diaphragm and actuator can be damaged when welding or bonding 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.

1. Remove the actuator from the valve body.
2. Weld the valve body into the pipeline.
3. After welding the surface of the valve body, smooth by sanding if necessary and clean carefully.
4. Install the actuator on the valve body.

Compressor Alignment

WARNING: Risk of crushing

If the compressor is not positioned correctly and the actuator is actuated, this may result in injuries and damage to the device. ▶ Before actuating the actuator, ensure that the compressor is in the correct position.

Maintenance

The device actuator is maintenance-free if the instructions in the operating manual are followed. Components which are subject to natural wear are seals and the diaphragm. If leaks occur, replace the affected wearing parts with suitable spare parts. The relief bore must be inspected at regular intervals for any medium leakages.