Cherry Electrical Products has released an application note giving details of its miniature switches and sensors for operating automated valves in inaccessible or remote locations or when the use of manual handwheels presents practical difficulties. Valves are often operated by a manual handwheel, but there are many circumstances when this is impossible – for example, when the size or differential of a valve means the handwheel pull is beyond manual limits, or when remote operation is specified. The solution is to mount a bezel gear onto the valve, driven by electric motor operators. Cherry’s mechanical SPDT switches are suitable for use in these applications, as they are low-cost and extremely reliable. Their small size means they can be assimilated easily into any design.
ry’s switches transmit the valve position through a signal line wired through the switch to the equipment or computer being signalled. They eliminate potential driven device damage due to over-torque conditions in either direction of operation. Another advantage offered by Cherry’s miniature switches is their high amp rating (from 0.05A to 25A) which enables the switch to control a relay or other plant devices, such as pumps or motors, in addition to transmitting valve position.
Valve applications often require the inclusion of sensors and here again, Cherry’s range of reed and solid state sensors offers the advantage of being sealed for protection and extended life in corrosive environments. In hazardous or remote locations, Cherry’s new DS hall sensor can be mounted in the same locations as a miniature switch and works in environments that must be contact-less. Actuated by a magnetic field, it meets the non-incendiary requirements for Division 2 hazardous locations.