Water Flow Switches

Lesker Water Flow Switches

The Kurt J. Lesker recommend installing a visual flow indicator on every water circuit to give the operator confirmation, usually by a simple spinning rotor, that water is flowing. Use flow indicators without switches when an interrupted supply will not cause damage or when the component has its own coolant alarm. For water-cooled components critical to the vacuum (diffusion pump, turbo pump) or those possibly damaged by flow failure (e-beam source, sputter gun) use a water switch with the indicator. The switch should connect to an alarm or process 'kill' button.

In a flow switch, a rotating magnet induces a current in an external coil. The current is sensed and compared to a variable set-point value. If the water flow decreases to a value below the set-point, a relay is de-energized. This arrangement ensures that a stuck rotor carrying the magnet cannot give a false positive flow indication.

Lesker Water Flow Switches