Bronkhorst CORI-FLOW - Manual (Page 9)

BRONKHORST CORI-TECH B.V.
Valves for gases
C0I / C1I valve
Direct operating valve for gases
metal sealed
C0I valve = normally closed
C1I valve = normally open
F-004AI valve
Direct operating valve for gases
and liquids. (bellow)
F-004AI valve =Normally closed.
C5I valve
Direct operating valve for gases
metal sealed
C5I valve = normally close d
1.2 Sensor principles
1.2.1 CORI-FLOW sensor
CORI-FLOW mass flow meters/controllers operate according to the Coriolis principle.
The instrument can be used to simultaneously measure the mass flow and temperature.
Measuring Principle
When a fluid flows through a vibrating tube, Coriolis forces are generated which bend or twist the tube.
The extremely small tube displacements are detected by optimally positioned sensors and evaluated
electronically.
Since the measured phase shift of the sensor signals is proportional to the mass flow, the CORI-FLOW
measures the mass flow directly. The measurement principle is independent of the density, temperature,
viscosity, pressure or conductivity. The tubes always vibrate at their natural frequency, which is a function
not only of the tube geometry and the tube material properties but also the mass of the fluid in the vibrating
tubes.
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.
Flow control
valve
9.17.031 page 9