Bronkhorst LIQUI-FLOW L30 - Manual (Page 8)

BRONKHORST HIGH-TECH B.V.
page 8 9.17.044
1.3 Valve principles
Control valves are not designed to provide positive shut-off, although some models have excellent
capabilities for this purpose.
It is recommended to install a separate shut-off valve in the line if required. Also pressure surges, as may
occur during system pressurisation must be avoided. The following models can be distinguished:
1.3.1 Solenoid valve
This is considered to be the standard (direct operated) control valve. In
general it is a normally closed solenoid valve. The plunger is lifted by the
force of the magnetic field of the coil. The orifice under the plunger is
removable for optimising the orifice diameter. Also a normally opened
solenoid valve is available.
1.3.2 Bellow valve
This valve type is a direct driven, low power, solenoid operated control valve. A special design, incorporating
a metal bellow allows for a relatively large orifice opening to be controlled. The design is suited for low
pressure or vacuum applications.
Flow control
valve