|Due to the risks of inhalation and splash /
irritation, all processes using methylene chloride are carried out within the confines of a fume cupboard. However, this does not entirely eliminate hazards, as human error can lead to fume cupboard doors being left open.
The team at the Halecombe Quarry laboratory has developed a cheap and simple adaptation for fume cupboards which further reduces hazards – by creating an automatic “shut off” when the doors to the fume cupboard are opened.
The use of isolation switches on the cupboard doors enables the air supply to the pressure filter to be cut, and the pressure in the filter released whenever the cupboard doors are opened – preventing splash and inhalation hazards. Isolator switches are fitted to the fume cupboard door, which allow the air supply unit to function only when the cupboard doors are shut. When the doors are shut, the electric circuit is complete and the valve can be opened, allowing air to pass into the pressure filter. When the doors are open, the valve closes, allowing the air to drain from the filter and release the pressure.
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Safer fume cupboards