Use CasesReducing chemical consumption by revising the pump

Liquid Type
Process Type


Local government (sewage treatment plant)

Customer's Needs and Problems

At a sewage treatment plant, the disinfectant sodium hypochlorite is injected into the treated water before it is discharged.
The equipment was deteriorating, so we were considering updating it.
The following problems were posed by the diaphragm pump that was conventionally used.

  • If operation is performed with a reduced stroke length when the amount of treated water is small, the gas generated from the sodium hypochlorite is retained in the pump head, causing the “gas lock phenomenon,” in which the pump operates with no liquid, to occur.
  • When a gas lock occurs, defective injection occurs until the air is released, so, in anticipation of the insufficiency during this period of time, the amount of injected sodium hypochlorite was set to a value larger than the rated volume.

TACMINA's Solutions

The customer learned of TACMINA’s Smoothflow Pumps at an exhibition and contacted us.
The customer checked the operation with the demo machine that our salesperson brought, confirming the high performance of this pump. This led to the customer switching to a Smoothflow Pump.

  • Each Smoothflow Pump uses an inverter to control the number of rotations, so the stroke length is always 100% even at low flow rates, which makes it difficult for the gas lock phenomenon to occur.
  • By reviewing the set injection amount and reducing the surplus injection, the customer was able to reduce the chemical consumption by 10%.
  • It was also possible to reduce the man-hours spend performing air release work.
  • The structure of the liquid end part is the same as that of a conventional diaphragm pump, so it was possible to smoothly transition to the new pump without requiring on-site maintenance training.