Burkert 20050334 (Type 2933) is a manually operated diaphragm valve actuator designed for hygienic or aggressive ambient conditions. This specific model features a diaphragm size of 25, a 45 mm PPS (Polyphenylene sulphide) handwheel, and a stainless steel bonnet. It is supplied without a valve body or diaphragm seal, allowing for flexible integration into existing systems or as a replacement actuator. The actuator has a compact, autoclavable design and is equipped with an optical position indicator with a scale and a single minimum stroke limiter (closing limiter).

Material Specifications

Element	Material
Handwheel	Polyphenylene sulphide (PPS), stainless steel 1.4308
Visual position indicator	Polyamide (PA), Stainless steel 1.4305
Valve spindle	Stainless steel 1.4305
Diaphragm bonnet	Stainless steel 1.4308, polyphenylene sulphide (PPS)

Actuator Dimensions

Note: Dimensions in mm, unless otherwise stated.

Diaphragm size	H1	H2	∅ B
8	54	49	35
15	84	78	45
20	95	86	45
25	101	90	45

Function and Position Indicator

By manually overriding the handwheel, the force is transmitted via a spindle and the valve is opened or closed. Turning the handwheel anticlockwise opens the valve, turning it clockwise closes it. To protect the actuator, we recommend not closing the actuator with more force than is required to close the valve tightly.

Turning the handwheel counterclockwise reveals the yellow position indicator and the scale marked on it as the valve opens further. The scale on the handwheel determines the rotation position of the handwheel (30 positions for Type 2933). The stroke scale shows the relative position of the valve and serves as a fixation point for determining the rotation position.

INFO

The visibility of the yellow mark is not directly correlated with the closed position of the valve. Depending on the structure of the valve, the marking may not be visible when the valve is open, or be visible when the valve is closed.

Setting Minimum Stroke Limit

A minimum stroke limit can be set for Type 2933. This setting also serves as a closing limiter to protect the diaphragm. A hexagon nut is used to do this.

1. By turning the handwheel clockwise, the valve is moved to the closed position.
2. Loosen the screw on the handwheel (hexagon socket, width across flats 2) and remove the handwheel.
3. Screw the hexagon nut as far as it will go. Minimum stroke is set.
4. Mount the handwheel on the actuator. The square on the spindle and the hexagon head of the nut must be correctly aligned to the geometry of the handwheel so that they fit into each other.
5. Tighten the screw on the handwheel with 0.9 Nm. If necessary, bond the screw to ensure a permanent hold.

WARNING

Damage to the device by incorrectly positioning the hexagon nut.

• Do not screw the hexagon nut in the area of the square.
• Only use minimum stroke limit in the 0…25 % opening stroke range.