Corrugated Plate Interceptor – allows the separation in the oily water treatment of the suspended solids and of the oil globules from water by gravity separation principle that is based on the difference of specific gravity between the phases (oil, solid, water). CPI is often used for a preliminary water treatment in order to process the waste water  before the flotators.

  • High efficiency suspended solids removal with Bulk Density greater than 1 Kg/l
  • Low water content in removed oil
  • Atmospheric and Pressure construction type
  • Anticorrosive coating both internal and external
  • Compact design
  • Low maintenance costs – No moving parts
  • Internals material: Glass fiber, plastic or steel material (Stainless Steel and Duplex construction)
  • Construction code: ASME VIII Div.1, PED
  • Continuous operation
  • Special Execution with U-Stamp and High Thickness Corrosion Allowance
  • Oil separation from process water
  • Oil separation from refinery waste water
  • Oil separation from ballast water
  • Oil separation from vegetable oil plant produced water
  • Solid separation from paper production plants water
  • Fats separation from slaughterhouses water
  • Many other possible applications

The fluid to be treated enters the CPI from the inlet nozzle then flows between the corrugated plates and reach the outlet nozzle, in laminar flow.

The inclination of the plates, usually of 45°, at the inlet part of the CPI allows a first separation of the suspended solids which are settled on the bottom. When, in the water to be treated, a large quantities of suspended solids are involved the inclination of the plates can increase up to 60°.

The fluid flows inside the plates where it occurs a thinner separation. The solids with high density settle at the bottom of the CPI while the oil drops float countercurrent to the surface, as per the Stokes’ law.

The plate pack minimizes the distance and the corrugated shape allow to the oil droplets to aggregate together (coalesce) forming larger droplets on the undersides of the plates and increasing rising velocity and efficiency.


Inlet oil content: 500 – 2000 ppm
Outlet oil content: 100 – 200 ppm
Inlet TSS content: 500 – 1000 ppm
Outlet TSS content: 100 – 250 ppm

The CPI can be supplied as package unit complete with instrumentation, ancillaries and automation (“plug-in” philosophy). Process data and fluid properties are considered in the design phase for sizing the equipment and for the choice of the materials (Glass Fiber,Plastic, Stainless Steel and Duplex construction).

CPI – Corrugated Plate Interceptors

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