流量报警器FA Application
The patented forked light-barrier FA-.., bi is
used in gas and water analysis for flow-monitoring
in flowmeters with measuring tubes
made of transparent material, e.g. Duran glass.
Thanks to optical scanning, very low flow
quantities can be detected even in flowmeters
with non-metallic or very small (1 mm)
floating balls.
Description
The patented M&C forked light-barrier FA-..,
bi consists of a compact aluminium body
with a fixed, open prism and a pressure
screw. This makes positioning of the sensor
FA-.., bi on the flowmeter’s measuring glass
very easy; it is not necessary to disassemble
the measuring glass. Three basic versions
cover a measuring glass diameter range of
5 - 55 mm.
Within the sensor’s body, a mechanically protected,
high-intensity LED is mounted on the
left side as a light source and two phototransistors
are mounted on the opposite side
as receivers.
The standard 3-meter long connection cable
exits on the left side adjacent to the pressure
screw. The LED emitters’ light beam is incident
on the photo-transistors through the flow
measuring glass. As soon as a floating ball
breaks the light beam, one or both of the
photo-transistors are blanked out.
The necessary FA-1.. electronic controllers
analyse this status changes accordingly. The
bi-stable operation of the FA-1.. electronic
controllers ensure identification of the set
flow rated value in the event of measured
values falling below or exceeding this pre-set
value with the sensor in any position. The
mono-stable operation of the FA-1.. electronic
controller indicates only whether the float is
located in the light beam of the light-barrier,
above or below it.
A special sensor head FA2-H is supplied for
temperatures up to +180 °C. Here, a fibreoptic
light guide is located in the sensor head.
Via this light guide the incident and
emergent light is conducted by the
transmitter/receiver located externally in a
separate adapter in the “cold area“.