The compact valves use two different drive and valve concepts, depending on the orifice size: the first is based on linear drive seat valves for orifices DN2 to DN6 (Type 3270: shut-off valve, Type 3280: proportional valve). The larger orifices, DN8 to DN25, rely on rotary drive disc valves. They are also available as shut-off (Type 3275) and proportional valves (Type 3285).
In the seat valves, the direction of flow against the seat is from below and feature high leak tightness and short closure times. In the disc valves the direction of flow against the seat is from above, these are claimed to have high pressure insensitivity. The valves are housed in a standard body with dimensions of 137 x 55 x 64mm in brass or stainless steel. For Types 3275 and 3285 there are three sizes due to the differing orifice sizes.
The valves offer an alternative to solenoid valves in less dynamic applications which do not require response times in the millisecond range. Bürkert says the motor actuated valves feature closure times of 2.5s, or 4s for disc valves. They are also claimed to achieve a higher flow coefficient in comparison to solenoid valves with the same orifice.
The valves can be used with combustible gases at pressures from 0 to 3bar, with neutral gases and liquids up to 6bar. The valves are designed for an ambient temperature from -10 to 60°C and fluid temperatures from 0 to 70°C.
