KF32RF1 KF40RF1 KF63RF1 KRACHT Gear Pump 25 bar 3000 rpm

Product Overview

The KF25, KF32, KF40, KF50, KF63, KF80, KF112 series gear pumps and KF32RF1, KF40RF1, KF63RF1 models with integral relief valves originate from the German KRACHT KF Series helical external gear pump platform. KRACHT is a family-owned enterprise founded in 1911, headquartered in Werdohl, Germany, and is a world-renowned specialist in fluid control. The KF Series is KRACHT’s classic medium-low pressure transfer pump product line, renowned for its helical gear construction, low pulsation, low noise, and modular design.

This series features helical external gear pumps (often referred to in the field as internal gear pumps), with displacements covering 2.5 – 3150 cm³/rev, standard operating pressure 25 bar, and peak pressure 40 bar. Pump housings are manufactured from grey cast iron or ductile cast iron, with gear components made from surface-hardened high-strength steel, positioned and secured by special composite plain bearing bushes. All pumps incorporate helical gear meshing and special tooth profile design, delivering the advantages of noise reduction and low pressure pulsation.

Key Interchangeability Advantage: Our KF series gear pumps are manufactured to strict German KRACHT original design specifications, ensuring 100% direct interchangeability with original units. All mounting interfaces, flange dimensions, shaft configurations, and port positions are identical to the original product—no modifications required. Every pump undergoes 100% factory performance testing under simulated operating conditions (covering rated pressure, peak pressure, and full speed range performance curves), guaranteeing plug-and-play reliability with zero performance deviation.

Model Code Breakdown (based on KRACHT KF Series designation rules):

• KF = Series: Helical External Gear Pump

• 25 / 32 / 40 / 50 / 63 / 80 / 112 = Nominal displacement (cm³/rev)

• RF1 = Mounting type and port configuration (flange mounting, SAE standard)

• D15 = Integral relief valve (optional)

Technical Specifications 

KF Series – General Specifications

• Product Series: KF Series Helical External Gear Pump (Medium-Low Pressure Transfer Pump)

• Brand: KRACHT (Germany)

• Displacement Range: 2.5 – 3150 cm³/rev

• Standard Operating Pressure: 25 bar

• Peak Pressure: 40 bar

• Speed Range: 200 – 3000 rpm

• Operating Temperature Range: -40℃ to +200℃

• Media Viscosity Range: 1.5 – 20,000 mPa·s

• Gear Type: Helical external gear, special tooth profile

• Housing Material: Grey cast iron EN-GJL-250 (GG 25) / Ductile cast iron EN-GJS-400-15 (GGG 40)

• Gear Material: 16 Mn Cr 5 case-hardened steel

• Bearing Type: Multi-component plain bearings

• Seal Type: Rotary shaft lip seal (NBR / FKM / EPDM / HNBR)

• Mounting: Flange mounting (DIN ISO 3019)

• Port Connections: KF 4…25: Whitworth pipe thread / KF 32…80: SAE flange

• Direction of Rotation: Clockwise or counter-clockwise (fixed)

• Mounting Position: Optional

KF25 Series

• Displacement: 25 cm³/rev

• Pressure: 25 bar (standard) / 40 bar (peak)

KF32 Series (including KF32RF1 / KF32RF1-D15) 

• Displacement: 32 cm³/rev

• Pressure: 25 bar (standard) / 40 bar (peak)

• Port Connections: SAE flange

• RF1: Flange mounting, SAE standard port configuration

• D15: Integral relief valve (overload protection)

KF40 Series (including KF40RF1 / KF40RF1-D15) 

• Displacement: 40 cm³/rev

• Pressure: 25 bar (standard) / 40 bar (peak)

• Flow Rate (@1500 rpm): Approx. 60 L/min

• Port Connections: SAE flange

KF50 Series

• Displacement: 50 cm³/rev

• Pressure: 25 bar (standard) / 40 bar (peak)

KF63 Series (including KF63RF1 / KF63RF1-D15) 

• Displacement: 63 cm³/rev

• Pressure: 25 bar (standard) / 40 bar (peak)

• Flow Rate (@1500 rpm): Approx. 94.5 L/min

• Port Connections: SAE flange

KF80 Series

• Displacement: 80 cm³/rev

• Pressure: 25 bar (standard) / 40 bar (peak)

KF112 Series

• Displacement: 112 cm³/rev

• Pressure: 25 bar (standard) / 40 bar (peak)

Important Note: KF Series Pressure Grade Distinction

⚠️ The KRACHT KF Series includes both low-pressure transfer pumps and high-pressure gear pumps:

• Low-Pressure Transfer Pump: Standard operating pressure 25 bar, peak 40 bar – corresponding to standard models KF25, KF32, KF40, KF50, KF63, KF80, KF112

• High-Pressure Gear Pump: Continuous operating pressure up to 250 bar, peak 300 bar – corresponding to models with specific suffixes such as KF2.5RF1-D15, KF4RF1-D15, KF5RF1-D15

The KF25–KF112 standard models and KF32RF1/KF40RF1/KF63RF1 queried by the user belong to the low-pressure transfer pump series, suitable for lubrication, transfer, circulation, and other low-pressure applications.

Key Technical Advantages

1. Helical Gear Construction for Ultra-Low Noise and Low Pulsation

The KF Series features helical gear meshing with special tooth profile design, combined with high tooth counts and trapped oil zone relief grooves, effectively reducing displacement fluctuation and pressure pulsation, significantly lowering pump and overall system noise. The helical gear design delivers smooth operation with minimal vibration, suitable for long-term continuous operation.

2. Modular Design for Flexible Configuration and Expansion

The KF Series employs standardized modular design, with displacement, flange, shaft end, rotation direction, and seal materials all customizable for easy upgrades and expansion. Optional Type D integral relief valve provides overload protection and simplifies external piping; optional magnetic coupling seal delivers zero external leakage; optional ATEX explosion-proof version adapts to chemical, marine, and other special applications.

3. High-Strength Materials and Composite Plain Bearings for Long Service Life

Pump housings are manufactured from grey cast iron or ductile cast iron, with gear components made from 16 Mn Cr 5 case-hardened steel, positioned and secured by multi-component composite plain bearing bushes. The combination of hardened high-strength gears and composite plain bearings delivers excellent wear resistance, rugged construction, and impact resistance.

4. Wide Media and Temperature Adaptability

The KF Series is suitable for pumping various liquids, compatible with mineral hydraulic oils, synthetic hydraulic oils, lubricating oils, fuel oils, thermal oils, and other self-lubricating media. Operating temperature range covers -40℃ to +200℃ with broad viscosity adaptability (1.5 – 20,000 mPa·s). Multiple sealing options (lip seals, mechanical seals, magnetic coupling) are available to meet diverse media requirements.

5. Excellent Self-Priming Performance and Wide Displacement Coverage

The KF Series offers excellent self-priming performance with displacement coverage from 2.5 to 3150 cm³/rev. Standard models from KF25 to KF112 meet various low-pressure transfer, lubrication, and circulation flow requirements, with tandem pump configurations also available.

Application Areas

• Equipment Forced Lubrication: Lubricating oil supply for fans, gearboxes, turbines, generator sets, wind turbine gearboxes

• Hydraulic System Charge Pumps: Charge pumps for closed-circuit hydraulic systems, low-pressure supply for small hydraulic power units

• Oil Circulation and Transfer: Cooling circuits, filtration system transfer pumps, thermal oil circulation

• Marine Industry: Marine gearbox lubrication, fuel transfer pumps

• Industrial Equipment: Air compressors, machine tools, compressor lubrication supply units

• Wind Power: Wind turbine gearbox lubrication systems

• Chemical and Plastics Industry: Polyurethane raw material transfer (isocyanate, polyol)

• General Industrial Fluid Transfer: Lubrication technology, fuel transfer

Expert Maintenance Tips

1. Rotation Direction Confirmation

KF Series pumps have a fixed rotation direction – verify pump rotation matches system drive direction before installation. Reverse rotation is strictly prohibited and will directly damage the shaft seal.

2. Media and Filtration Requirements

Media must have lubricating properties and must not contain solid particles. Recommended filtration precision ≤ 25 μm to prevent gear and bearing wear.

3. Integral Relief Valve Usage Notes

If equipped with Type D integral relief valve (e.g., KF32RF1-D15), the valve is for overload protection only – do not operate in continuous relief mode, as the pump will rapidly overheat and become damaged. For continuous pressure regulation, an external relief valve should be installed separately.

4. First Start-Up and Oil Priming

Prime the pump housing with clean media before first start-up; ensure suction lines are fully filled – never run dry. Maintain operating temperature within -40℃ to +200℃. Speed range: 200 – 3000 rpm.

5. Complete Model Confirmation

Complete order model should include: displacement size, rotation direction, relief valve option, shaft type, seal material. Within the same KF Series, low-pressure transfer pumps (25 bar) and high-pressure gear pumps (250 bar) have different suffixes – verify pressure grade carefully during selection.