PAHF 20

Summary

Product Identification

The Danfoss PAHF series are high-pressure axial piston pumps designed for the high-pressure water mist fire extinguishing industry, suitable for both land and marine applications. They are water-lubricated and feature a compact design.

• Pump Types: PAHF 20, PAHF 25, PAHF 32, PAHF 40
• Geometric Displacement:
  • PAHF 20: 20 cm³/rev
  • PAHF 25: 25 cm³/rev
  • PAHF 32: 32 cm³/rev
  • PAHF 40: 40 cm³/rev
• Overall Flow Range: 14 to 115 l/min (3.7 to 30.3 gpm)
• Material: All parts made of noncorrosive material. Weight (stainless): 15.6 kg (34.4 lbs) for all models.
• Maintenance: Maintenance-free over their entire service life, with no preventive maintenance required (e.g., no periodic lubricant or wear part changes). A service life of 500 hours is noted in the features.
• Associated Valves: The pumps are designed for direct mounting of dedicated valves:
  • Relief valve (type VRHF)
  • Relief/bypass valve (type VPHF)
  • Check valve (type VCH)

Pump Code Numbers

• PAHF 20: 180B0092
• PAHF 25: 180B0093
• PAHF 32: 180B0094
• PAHF 40: 180B0095

Operating Limits

• Max. Continuous Outlet Pressure: 160 bar (2320 psi)
• Short-term Outlet Pressure Peaks: Up to 200 bar (2900 psi) (e.g., with valve closing)
• Fluid Temperature:
  • Min. +3°C, max. 50°C at max. continuous pressure
  • Min. +3°C, max. 60°C at max. 100 bar
• Ambient Temperature: Min. 0°C to max. 50°C
• Storage Temperature: Min. -40°C to max. 70°C
• Max. Speed (Boosted Supply):
  • PAHF 20, 25, 32: 3600 rpm
  • PAHF 40: 3000 rpm
• Max. Speed (Tank Supply): 1800 rpm (all models)
• Min. Speed: 700 rpm (all models)
• Minimum Flow Consumption (for temperature control): For PAHF 40 at 3000 rpm, 105 bar, a minimum of 24 l/min is recommended to prevent overheating when water is recirculated.

Feed Water

• Water Quality: Drinking water quality, conforming to EEC directive 98/83/EC. Must be clean and free from sediments.
• Filtration: Must be filtered through a 10 µ absolute, β₁₀ value > 5000 filter.
• Inlet Pressure (Boost Pressure):
  • Recommended normal boost pressure: 1-6 bar (14.5-87 psi) (2-7 bar (43.5-101.5 psi) absolute)
  • Short-term inlet pressure peaks: Must not exceed 30 bar (435 psi)
  • Max. during static standstill: 10 bar (145 psi)
  • The inlet pressure must never exceed the outlet pressure.
• Antifreeze Protection: If exposed to freezing temperatures, the pump must be protected. Danfoss recommends DOWCAL N or CHILLSAFE (biologically degradable Mono Propylene Glycol) with a minimum 30% mixture ratio.
• Corrosion Protection: If decommissioned for more than 4 weeks or in transportation, the pump must be preserved against corrosion. Do not simply drain the pump.

Electrical

Typical Motor Sizes (at max. pressure)

VPHF 100 Bypass Valve Coils (Ordered Separately)

• 10 W a.c. with terminal box:
  • 24V 50Hz (Code: 018F7920)
  • 220V 50Hz (Code: 018F7921)
  • 240V 50Hz (Code: 018F7924)
  • 24V 60Hz (Code: 018F7922)
  • 110V 50/60Hz (Code: 018F7923)
• 18 W d.c. with terminal box:
  • 12V DC (Code: 018F7913)
  • 24V DC (Code: 018F7914)
  • 24V 50Hz (Code: 018F7928)

Mechanical / Hydraulic

• Shaft Load: The pump must not be exposed to axial or radial loads. A flexible coupling is recommended for connection to the motor.
• Direction of Rotation: CCW (counter clockwise) or CW (clockwise), indicated by an arrow at the inlet side.
• Mounting Orientation: Can be mounted in any horizontal position or vertically with the shaft upwards. Cannot be vertically mounted with the shaft facing downwards.
• Connections:
  • Outlet (O): Use PAHF adaptor or VRHF100 Relief valve (thread size 3/4" BSPP). Max tighten torque: 150 Nm (133 lb(f) ft).
  • Inlet (I): 1 1/4” BSPP with 20mm long thread. Max tighten torque: 150 Nm (133 lb(f) ft).
  • Bleeding (C): M6 (width across flat = 5mm). Max tighten torque: 4 Nm (3 lb(f) ft).
  • Gauge Port Inlet (XI): 1/4” BSPP with 15mm long thread. Max tighten torque: 15 Nm (11 lb(f) ft).
  • Gauge Port Outlet (XO): 1/4” BSPP with 15mm long thread. Max tighten torque: 15 Nm (11 lb(f) ft).
  • Parallel Key: 8 × 7 × 32 DIN 6885.

Flow Calculation Formulas

• Theoretical Flow (Qth): Q (th) [l/min] = pump displacement in cm³ × rpm/1000
• Flow at any pressure (Qeff): Q eff = Q (th) – [(Q (th) – Q (p max)) × ( p / pmax )]
  • Where Q (p max) is flow at max. pressure, p is current pressure, pmax is max. pressure.

Power and Torque Calculation Formulas

• Required Motor Power (P): P [in kW] = (Speed [in rpm] × displacement per rev [in ccm] × pressure [in bar]) / (600,000 × η mech)
• Required Torque (M): M [in Nm] = (Displacement [in ccm] × pressure [in bar]) / (62.8 × η mech)
• Mechanical Efficiency (η mech): 0.9 for PAHF 20, 25, 32, 40.

Associated Valves

VRHF 100 Relief Valve

• Code Number: 180G0011
• Mounting: Directly mounts on PAHF 20-40 pumps using 4 M8 screws, adding a 3/4" thread.
• Function: Protects system components from overload due to pressure peaks and controls/limits system pressure by draining surplus water.
• Technical Data:
  • Pressure setting range: 80-140 bar
  • Setting screw travel: 6.2 mm
  • Max. flow: 100 l/min
  • Max. fluid temperature: 50°C
  • Max. ambient temperature: 50°C
  • Internal leakage (20% below max. setting pressure): up to 1.0 l/min
  • Filtration: 10 µ abs. β₁₀ >5000
  • Weight: 2.8 kg
• Connections:
  • Outlet (O): 3/4" BSPP, 150 Nm
  • Return (XR): 3/4" BSPP, 150 Nm
  • XO / XR: 1/4" BSPP, 15 Nm
  • XRT: 1/2" BSPP, 15 Nm

VPHF 100 Relief/Bypass Valve

• Code Number: 180G0010
• Mounting: Directly mounts on PAHF 20-40 pumps using 4 M8 screws, adding a 3/4" thread.
• Function: Combines relief valve functionality (as VRHF 100) with a bypass valve for unloaded pump start.
• Relief Valve Technical Data: (Same as VRHF 100)
  • Pressure setting range: 80-140 bar
  • Setting screw travel: 6.2 mm
  • Max. flow: 100 l/min
  • Max. fluid temperature: 50°C
  • Max. ambient temperature: 50°C
  • Internal leakage (20% below max. setting pressure): up to 1.0 l/min
  • Filtration: 10 µ abs. β₁₀ >5000
  • Weight: 7 kg
• Bypass Valve:
  • Type: Normally Closed (NC) 2/2 way, pilot operated On/Off – seat valve, electrically activated by a coil.
  • Max. pressure loss: 10 bar at max. flow.
  • Closing time: approx. 1000 ms.
• Connections: (Same as VRHF 100)
  • Outlet (O): 3/4" BSPP, 150 Nm
  • Return (XR): 3/4" BSPP, 150 Nm
  • XO / XR: 1/4" BSPP, 15 Nm
  • XRT: 1/2" BSPP, 15 Nm

VCH Check Valve

• Code Number: 180H0117
• Flow Capacity: Up to 150 l/min.
• Port Sizes: 3/4" in and out.
• Pressure Loss: Max. 2 bar.

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Disclaimer: This summary is based on extracted text and may not include all figures, footnotes, or the latest revisions from the official OEM PDF datasheet. Contractual data must always match the specific OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror