KF8 KF25 KF32 KF40 KF50 KF63 KF80 KF112 KF125 KF200 KRACHT Gear Pump 25 bar

Product Overview

The KF8, KF25, KF32, KF40, KF50, KF63, KF80, KF112, KF125, and KF200 series gear pumps 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.

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

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

• Gear Type: Helical external gear, special tooth profile

• Housing Material: Grey cast iron / Ductile cast iron

• Gear Material: Surface-hardened high-strength steel

• Bearing Type: Special composite plain bearings

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

• Optional Configurations: Type D integral relief valve, magnetic coupling seal, ATEX explosion-proof version

• Mounting: Flange mounting (ISO or SAE standard)

KF8 Series

• Displacement: 8 cm³/rev

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

KF25 Series

• Displacement: 25 cm³/rev

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

KF32 Series

• Displacement: 32 cm³/rev

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

KF40 Series

• Displacement: 40 cm³/rev

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

KF50 Series

• Displacement: 50 cm³/rev

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

KF63 Series

• Displacement: 63 cm³/rev

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

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)

KF125 Series

• Displacement: 125 cm³/rev

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

KF200 Series

• Displacement: 200 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 KF8, KF25, KF32, KF40, KF50, KF63, KF80, KF112, KF125, KF200

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

The KF8–KF200 standard models 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 (Z=14) 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 surface-hardened high-strength steel, positioned and secured by special 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. 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 KF8 to KF200 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: Fluid transfer and circulation

• 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, 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℃.

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.