C.M.O. POMPE s.n.c.

- Model PS/PST Series - Single Screw Pump


The CMO pumps with worm feed screw belong to the rotating positive-displacement pump category. With simple construction, the pumps are intended above all for pumping dense and/or viscous fluids.


The capacity varies depending on the rotor step. The PS series covers a capacity range from 50 to 4000 l/min. The pressure varies with the length of the stator from 0 to 30 bar.

The parts in contact with the liquid are constructed in various materials, depending on the fluid to be pumped. The rotating parts are normally in casehardening or chromium-plated steel or in stainless steel 304 or 316. The stators are constructed in natural or synthetic rubber in different mixes (Viton, Silicon, Perbunan, etc.). Specific materials can be used on request.


The applications for this type of pump are virtually infinite, due its special construction, the materials used, the technical measures adopted and the singular working mechanism guarantee maximum performance whether pumping brackish water, stall waste, unicellular cement, marble sludge, lime putty, synthetic resins, foundry sludge, etc. When pumping fluids with density and/or abrasion characteristics different to those of water, it is recommended never to reach the pressure limit and capacity values expressed in the table.

For correct function of the pump, it is recommended to check that air is not being suctioned and that the supply of fluid to be pumped is constant to avoid the pump turning dry.

The values featured in the table refer to tests performed with fluids with characteristics similar to those of water.


The worm screw CMO pump belongs to the rotating positive-displacement pump category. Its main components are:

  • Rotor normally in chromium-plated steel or stainless steel.
  • Stator composed of a steel container inside which a seat in rubber (or other material depending on requirements or working conditions) is vulcanised and suitably treated with an antacid material that can be wiped.

The stator-rotor unit is delimited by a sealing ring that, during the rotation movement, prevents air from entering, thereby guaranteeing the positive-displacement suction capability.

The CMO pump features an extremely simple and precise construction, qualities which guarantee correct function of the pump. The conductor shaft is supported by two ball bearings and is sealed at the pump body by an efficient sealing system that the Client can choose as an optional.
The rotating movement of the conductor shaft is transmitted to the rotor by means of a homokinetic drive system, safeguarded by strong rubber protections.
In order to assist use of our pumps, we have installed the suction tubing attachment on three sides of the pump body to be used as required.

The CMO pump is used to resolve multiple application pumping problems.
For example:

  • In the AGRICULTURAL sector for removing stall waste, diluted droppings, for irrigation, etc.
  • In the CHEMICAL sector for pumping products such as: synthetic resins, magnesia, lye, pastes, varnish, paint, acid, wax, fungicides, petrol, oil, printing inks, etc.
  • In the BUILDING sector for pumping unicellular cement, lime putty, etc.
  • In MARBLE SAWMILLS for eliminating marble sludges.
  • In TANNERIES, for removing water with tanning residues, oils, tannin, etc.
  • In DEPURATION PLANTS for feeding centrifugal systems and filters, for conveying various sludges.
  • In the FOOD INDUSTRY for conveying flour soaked with water, preserves, jams, sugar solutions, fruit juice, chocolate mixtures, glucose, honey, cream, milk, melted cheese, butter, dehumidified wines, bunches of grapes.
  • In the PHARMACEUTICAL AND COSMETIC INDUSTRY for pumping various creams, toothpaste, soap, detergents, shampoo, hand soaps, etc.

The CMO pumps function thanks to a tested mechanism composed of a chromium-plated or stainless steel worm screw and by a stator covered on the inside in plastic. Rotation of the worm inside the stator creates a series of hermetic gaps that are moved along the suction-delivery axis thereby creating the pumping action (see diagram at right).

This type of pump can be used for an infinite number of applications due its special construction, the materials used, the technical measures adopted and the singular working mechanism that guarantees maximum performance whether pumping must or milk, chocolate, synthetic resins, bitumen or foundry sludge.

The SINGLE SCREW series of pumps are:

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