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VAS - Vertical acid pump

The VAS pumps is a vertical acid pump offering high corrosion resistance


Vertical acid single stage pump with closed impeller - Vertical construction for clear and corrosive liquids

The VAS pump is special ly designed and manufactured to provide key product features for sulfuric acid pumping applications. Its proven reliable design offers both high corrosion resistance and mechanical performance.

General design :

Vertical turbine pump with discharge through column

Hydraulics :

  • Impeller : mixed flow hydraulic with diffuser
  • Absence of radial loads on colum bearing thanks to the concentric discharge bowl
  • Axial loads fully balanced by front and rear casing wear rings
  • Multistage design available upon request

Bearing :

  • Grease-lubricated bal l bearings

Lineshaft and shaft sealing :

  • Simple shaft sealing by throttle bush with liquid back to the tank
  • Auxiliary packing rings to prevent acid vapors (for safety and maintenance)
  • Mating surfaces are protected against acid corrosion for improved maintenance
  • Threads protected by cap nuts and O-rings
  • Return of the pumped fluid to the tank : Acids leaks are collected and returned to tank.
    Thus avoiding contact with suspension pipes and consequently potential corosion.


- Capacity : up to 2500 m³/h (10,000 US gpm)
- Total head : up to 45 m (148 ft)
- Maximum operating pressure : 20 bar (290 PSI)
- Operating temperature range : up to 140° C (291° F) (special model for high temperatures : heat recovery system service at 230° C (450° F))
- Higher capacities and heads upon request

Standard Materials

Concentration range : 90 to 99,5%

Temperature range : up to 140° C (291° F) :

- Pump casing in acid-proof cast iron or special stainless steel
- Sulfem© and special stainless steel for impeller, wear rings and shaft sleeves
- Sleeve bearings in ferro-silicium or special alloy
- Shaft made of duplex stainless steel , with FEP lining

Industrial Applications

• H2SO4 production plants :

- Absorption
- Drying

• Engineered design for Heat Recovery System application

Additional Models

VAS Pump for Heat Recovery System

Our engineered pump design for the Heat Recovery System applications offers the most reliable and safest pumping solutions for acids with high temperature up to 230° C and for the environment protection.


Key features of the VAS pumps for Heat Recovery System

Sealing System :

Thanks our experience in severe oil and gas applications, Ensival Moret recommends two systems. Both systems ensure no contact between the pumped acid and the sealing system :

  • The safest solution with a double dry air pressurized mechanical seals
    This technology comes from compressors applications and provides maximum safety and reliability.
    The flow and the pressure are controlled in permanent way thanks to a monitoring panel.

  • Alternative solution with a cartridge mounted single mechanical seal with dry air pressurized lubrication
    For safety reasons, the minimum required system by Ensival Moret is a cartridge mounted single mechanical seal for easy maintenance and designed for a dry air pressurized lubrication as per API 32.

Bearing :

  • Oil lubricated bearing

  • Air forced cooling system in order to avoid risks of overheating.
    The bearing is designed with efficient airfins and bearing fan to reduce temperature.
    In addition to a higly securised sealing system, the absence of water cooling set the VAS pump as the safest solutions for pumping acid with high temperatures.

Materials of construction :

  • Main parts in 310SS

  • Sleeve bearings in high corrosion resistant materials