The BURKERT 348055 (Type 2031) is an externally controlled 2/2-way diaphragm valve consisting of a pneumatically operated piston actuator, a diaphragm, and a stainless steel valve body. The proven and robust PA (Polyamide) actuator ensures reliable operation in hygienic or aggressive environments. The flow-optimised valve body with minimal dead space enables high volume flow rates and a wide range of possible applications. This specific model features a weld end connection (DN 15), a PTFE diaphragm with an EPDM backing membrane, and operates with Control Function A (normally closed by spring force). It is designed to handle medium temperatures from -10 °C to 100 °C and operating pressures up to 10 bar.

Product Overview

Item	Description	Item	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

Technical Data

Permissible Temperatures

Ambient Temperature

Actuator housing material	Actuator size	Permissible ambient temperature [°C]
PA	≤125 (H)	-10...+60
PA	≥175 (K)	-10...+50

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. The functional properties and, in particular, the service life of the diaphragm can deteriorate as the medium temperature rises. Do not use the diaphragms as a steam shut-off element.

Diaphragm material	Medium temperature [°C]	Comments
PTFE (EA)	-10...+130	Steam sterilisation max. +140°C for 60 min

Risk of bursting due to overpressure

If the device bursts, escaping media may cause injuries, burns or scalds. Do not exceed the maximum permissible pilot pressure or maximum permissible operating pressure. Observe the permissible ambient temperature and medium temperature.

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: The inclination angle is determined by the installer or operator. 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 (diaphragm size) and the inner diameter of the port connection (nominal diameter). 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

Damage to the diaphragm or the actuator

The diaphragm and actuator can be damaged when welding or bonding the valve body into the pipeline. 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. After welding, smooth the surface by sanding if necessary and clean the valve body carefully.
3. Install the actuator on the valve body.

Compressor Alignment

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.

Repair and Maintenance

Replacing the Diaphragm (Control Function A)

Risk of injury from sudden discharge of pressure and escaping medium

Disassembling a pressurised device can cause medium to escape unexpectedly or a sudden discharge of pressure. Before disassembly, shut off the pressure and vent all lines. Completely drain the lines.

1. Clamp the valve body in a holding device (only for devices which have not yet been installed).
2. Pressurise the lower pilot air port with compressed air (value as indicated on the type label): valve opens.
3. Loosen the body screws crosswise and remove the actuator and diaphragm from the valve body.
4. Unbutton or unscrew the old diaphragm. When fastening with a bayonet catch, loosen the diaphragm by rotating it 90°.
5. Ensure the correct position of the compressor.
6. Attach the new diaphragm to the compressor according to the fastening type. The identification tab must be perpendicular to the flow direction.
7. Place the actuator together with the diaphragm on the valve body.
8. Slightly tighten the body screws crosswise until the diaphragm rests between the valve body and the actuator. Do not fully tighten the screws yet.
9. Actuate the valve twice to position the diaphragm correctly.
10. Switch off the pilot pressure.
11. 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.

Changing the Seal Set

Item	Description	Item	Description
1	O-Ring	15	Lip seal
6	Piston seal	17	O-Ring
22	O-Ring

Risk of injury when unscrewing the transparent cap

If the transparent cap is pressurised when it is unscrewed, it can cause serious injuries due to high force and speed and an uncontrolled trajectory. Before unscrewing the transparent cap, ensure that the upper piston chamber is depressurised.