Diaphragm NSP

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The NSP pumps are used for high precision services that will meter linearly from 0-100% of their rated capacity with errors of less than 1%.

The NSP pumps may be used to measure or control flow.

As a final control element, the NSP pump may be remotely, electrically or pneumatically, controlled by remote process control instruments.

Projected to operate in a large variety of chemical processes, the NSP may be used to handle the most severe products such as chemical slurries, viscous liquids, high temperatures fluids, corrosive and toxic liquids and others.



How the NSP pump works

A combination between a plunger pump and a diaphragm pump, the NSP is a positive displacement pump in which a high precision piston in an alternating movement displaces a determined quantity of oil and in turn, this oil hydraulically moves the diaphragm, which has the function of separating the liquids, in the same alternating movement. The diaphragm on the opposite side displaces the process liquid through the inlet and outlet check valves. (please check figures 1 and 1a)

The hydraulic system is automatic. Any loss in hydraulic oil is compensated on the suction stroke by the vacuum compensating valve that draws in oil from the main pump reserve in the pump housing.

The NSP pump has an incorporated pressure relief valve responsible for eliminating the excessive pressure in the pumping chamber, on the diaphragm or in the discharge piping also eliminating the need for relief valves in the discharge piping of the pumped liquid.



  • Main details as to maximum pressure and maximum capacity for the NSP pumps, may be consulted in the charts below1; and
  • Pumps with plastic heads will give the same capacities; however, the maximum pressure is limited to 10kg/cm².


  • The viscosity of the fluid and the circuit of the piping will influence the correct pulsation rate to be adopted.
  • Low pulsation rates should be used in pumping (i) high viscosity liquids; (ii) when the vapor pressure of the pumped fluid is high; (iii) in long pipelines; (iv) low NPSHr.
  • The pulsation rate may be varied by several means, such as (a) different reduction ratios in the pump, (b) additional speed reducers between motor and pump or (c) use of variable speed drives.
  • Various pumps may be mounted in parallel to obtain higher capacities


  • Pumping heads: manufactured in stainless steel 304 or 316, HASTELLOY B or HASTELLOY C, ALLOY-20, MONEL, SS 304L or 316L, and plastic materials such as PVC, PTFE, Polypropylene, epoxy resins, and other, subject to future consultation.
  • Diaphragms: manufactured in PTFE, stainless steel, and in the case of tubular diaphragms rubbers such as neoprene, BUNA-N, Viton, and other, subject to future consultation.
  • Check valves: manufactured stainless steel 304 or 316, HASTELLOY B or HASTELLOY C, Alloy-20, MONEL, SS 304L or 316L or plastic materials such as PVC, PTFE, polypropylene, epoxy resins and other, subject to future consultation.
  • Valve balls: manufactured in stainless steel 316, HASTELLOY B or HASTELLOY C, ALLOY-20, ceramic, saffire, PTFE and other, subject to future consultation.


The NSP pumps may be used in chemical, petrochemical, food, water and waste water and nuclear plants, among others. The products to be pumped may be corrosive, toxic and radioactive liquids, subject to future consultation for further information.

Application characteristics

  • Single diaphragm heads: attend all simple applications.

  • Triple diaphragm heads: destined to handle highly dangerous liquids, inflammables, toxic and that require an extra protection.

  • Tubular diaphragm heads: applied to liquids with fine solids in suspension due to their abrasive nature.

  • Remote pumping heads: used for applications such as high or low temperatures, radioactive liquids (that need to be isolated or confined in a separate room or cell. In this arrangement, only the pumping head is within the enclosure and the rest of the pump is maintained out of the cell and separated from the hydraulic extension).


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