Fume bench- and hood controllers
Fume Hood Control FHC
Fume hood control system
Description
The fume hood control unit, FHC, which is based on a micro processor, has two analogue outputs (volt/mA), one for velocity and one for control of the damper actuator.
The alarm function of the FHC fume hood controller has two voltage free relays which can be programmed for high or low flow for each mode of operation and with programmable time delay. The alarm function can also be used for electric interlock for example of heating in the fume hood so that the heating is stopped at a low velocity. If the flow is too low, a built-in buzzer will sound after set time delay. After a set time delay, the relay operates and the heating will be stopped. Resetting of the alarm before the relay responds prevents the electric interlock. The velocity can be set from a distance to be high or low.
Functions
The fume hood control unit, FHC, has a built in sensor. The sensor is used for measuring the velocity of the fume hood sash opening.
The sensor consists of a bi-directional mass flow sensor with very small pressure range, 0...4 Pa, corresponding to » 0...2,0 m/s. The pressure difference is measured between the fume hood and the laboratory.
The time constant for the sensor is less than 3 msec. The sensor has an excellent long time stability.
The connection of the sensor to the fume hood is made through a self-averaging pressure connection. Zero setting and calibration is made through the operator fume hood monitor, FHM.
Relevant documents
MicaFlex Fume Hood Control
Declaration of conformity
Installation manual
Programming instruction
Operator instruction