Rotary SolenoidsChlorine gas used for water purification and manufacturing processes is stored in heavy steel bottles. In water purification plants, the bottles of chlorine gas are generally stored in their own room for safety reasons. The bottles being used are hooked to tubing which delivers the chlorine gas to its point of consumption.

Each bottle contains a valve which must be operated manually to start or stop the flow of chlorine gas from the bottle. Since there are connections to the tubing and seals around the valve stems, there are possibilities of the chlorine gas leaking out into the room. As chlorine gas is very poisonous, it would be unsafe for anyone to enter a room containing a leaking chlorine system.

Since there are detectors which indicate the presence of chlorine gas, a warning system can be put in place to warn anyone who may need to enter the chlorine gas storage area. The warning system would allow ventilating of the room if chlorine gas is present. As a further safety measure, it is desirable to close off the flow of chlorine gas from each bottle before entering the storage room. This means that the valves on the bottles must be remotely operated.

An automatic, electrical valve control mechanism required the following unique features:

  • It must electrically operate in one direction only.
  • It must turn 180°.
  • It must not interfere with the manual operation of the valve.

Although an electric motor was considered as an operator for the valve, it was rejected due to the fact that there is a possibility that the wiring could be changed so that the motor could be made to inadvertently run backwards. This would allow the motor to open the valve as well as to close it.A Saia-Burgess rotary solenoid with engaging ratchets was selected as the ideal valve control. By pulsing the solenoid, it can step through 180°. There is no way of rewiring it to cause it to turn in the opposite direction. The valve mechanism is always disconnected from the solenoid when there is no electrical power to the solenoid coil. The rotary solenoid was implemented as the ideal mechanism for this safety application.