Pall HNP022 Series Oil Purifier

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Pall HNP Vacuum Dehydrators

Pall HNP022 Series Oil Purifier

The Pall HNP022 Series Oil Purifier is designed for use with small to medium oil systems, particularly where high viscosity fluids are employed, and can effectively remove 70 litres of water per day from the oil.

Water in hydraulic, lubrication, power transmission and insulating fluids adversely effects fluid performance and is a threat to system reliability. This often invisible contamination promotes oil oxidation, the formation of acids, bacterial growth, and can lead to a reduction in lube film thickness. In time, this results in corrosion, increased wear and expensive system failure. When free water contamination interacts with system fluids the consequences are increased operating costs from reduced oil life and increased fluid replacement and
disposal costs.

Benefits of the Pall HNP022 Series Oil Purifier

  • High performance water, gas and particulate removal
  • Extension of fluid life
  • Minimised corrosion within systems
  • Reduced fluid disposal
  • Reduced operating costs
  • Increased equipment reliability
  • Simple automated operation


The Pall HNP fluid conditioning purifier uses vacuum dehydration to remove 100 % free water and as much as 80 % of dissolved water. It will also remove 100 % of free and entrained gases and up to 80 % dissolved gases. Vacuum dehydration is the most effective method of water removal at minimum cost and ease of use. Unlike other methods it removes both free and dissolved water and cannot burn or otherwise significantly alter the properties of the oil. Particulate contaminant removal is achieved using high performance rated (ß3(C) >1000) Ultipleat® SRT filter elements. In addition, a WS10 Series water sensor measures water content and temperature at purifier inlet, allowing the purifier to operate only when the water content rises above a pre-determined level.
Pall HNP022 Series Oil Purifier

Removing Free Water is never enough!


  • Initial water content is above saturation (free water).
  • Maximum water removal capability of “free water removal” devices (coalescers, centrifuges, etc.) is to the oil’s saturation point.
  • Water content achieved with mass transfer dehydration us significantly below the oil’s saturation point.
  • Water content achieved with mass transfer dehydration remains below the oil’s saturation point even after the oil is cooled by the system heat exchanger. This prevents the formation of harmful free water.
  • If only free water is removed at initial temperature, when oil is cooled the amount of harmful free water in the oil can increase significantly.


Pall HNP022 Series Oil Purifier

1342 mm x 578 mm x 1504 mm
Dry mass
250 kg (551 lb)
Inlet/Outlet connections
See table 4 below
Max. Recirculation Flow rate
25 L/min (6.6 US gpm)
Water removal rate*
70 L/day (18.5 US gpm)
Inlet pressure
1.5 barg (21.8 psig) maximum
System back pressure
4.6 barg (66.7 psig) maximum
Fluid temperature
+10 ºC (50 °F) to +70 ºC (158 °F)
Fluid viscosity
700 cSt maximum
Operating vacuum
-0.6 barg (18″ Hg) to-0.9 barg (27″ Hg) (adjustable)
Power supply
See Table 1
Total Motor power
2.22 kW maximum

Materials of Construction

Base frame
Carbon Steel, painted
304 Stainless steel
Hydraulic fittings
Zinc plated carbon steel
Control box
Carbon steel, painted
Hydraulic hoses & seals


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