Background and Solution
In a smart tandem pumping system, a pneumatically actuated 3-way ball valve is used to divert material into the process as the pumps crossover at the empty signal produced by the pneumatic crossover. One particular customer was using this ball valve under the control of the PLC. The ball valve was triggered via a solenoid through the PLC which was activated by an electric trip switch on the ram. This was not accurate enough, as the valve would actuate long before the pump would reach the pneumatic switch used to activate the pump crossover.

To ensure a smooth transition, the airline form the active ram was split to send an air signal directly to the actuator, with eliminated the need for a solenoid valve. As the actuator came equipped with a spring return, only one side of the actuator needed air to function.

The customer can now use their 3-way ball valve, properly timed with the pump’s A-to-B transition on the tandem set of pumps.