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.
SolutionTo 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.
Results
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.