IPH-24A NACHI Double Internal Gear Pump 6.5/25 cc/rev

Product Overview

The NACHI IPH-24A, IPH-34B, IPH-36B and IPH-36A Double IP Pump Series is a high-pressure fixed-displacement internal gear pump family designed for hydraulic systems requiring stable flow, low pulsation and reliable operation.

The IPH design uses a modified involute short-tooth internal gear arrangement to reduce pulsation and operating noise. NACHI also employs an axial and radial pressure-loading system intended to maintain high efficiency under demanding pressure conditions. The manufacturer specifies rated pressure up to 21 MPa and maximum pressure up to 30 MPa for the applicable IPH series configurations.

The double-pump architecture combines two independently sized pumping sections within one assembly, allowing different displacement combinations to be selected for two hydraulic circuits while maintaining a common drive arrangement. NACHI states that the individual pump performance corresponds to the respective single-pump characteristics.

For replacement applications, our IPH-series replacement pumps can be engineered around the original model code, displacement combination, mounting interface, shaft configuration, rotation direction and inlet-port arrangement, followed by 100% simulated operating-condition testing before shipment.

Technical Specifications

IPH-24A-6.5-25-T-11

• Brand: NACHI
• Series: IPH
• Pump Type: Double fixed-displacement internal gear pump
• Head-side displacement: 6.5 cm³/rev
• Shaft-side displacement: 25 cm³/rev
• Mounting method: A, foot mounting
• Auxiliary symbol: T, screw-in flange kit for shared IN port
• Design number: 11
• Rated pressure: 21 MPa
• Maximum pressure: 30 MPa
• Minimum speed: 600 min⁻¹
• Maximum speed: 2000 min⁻¹
• Control: Fixed displacement
• Exact OEM weight for this T-configured model: not separately confirmed in the retrieved official source

NACHI’s official IPH-24A listings confirm the double-pump format and displacement combinations around this configuration, including 5/25 and 8/20 cm³/rev variants.

IPH-34B-10-25-10

• Brand: NACHI
• Series: IPH
• Pump Type: Double fixed-displacement internal gear pump
• Head-side displacement: 10 cm³/rev
• Shaft-side displacement: 25 cm³/rev
• Mounting method: B, flange mounting
• Design number: 10D
• Current NACHI design reference: 11D / -11
• Rated pressure: 21 MPa
• Maximum pressure: 30 MPa
• Minimum speed: 600 min⁻¹
• Maximum speed: 2000 min⁻¹
• Control: Fixed displacement
• Exact 10D configuration weight: not separately confirmed in the retrieved OEM source

NACHI’s current IPH-34B documentation lists 10/25 cm³/rev as a standard displacement combination, while the current design documentation uses the 11D generation.

IPH-36B-13-80-11

• Brand: NACHI
• Series: IPH
• Pump Type: Double fixed-displacement internal gear pump
• Head-side displacement: 13.3 cm³/rev
• Shaft-side displacement: 81.3 cm³/rev
• Mounting method: B, flange mounting
• Rotation: Clockwise in the standard configuration
• Design number: 11
• Rated pressure: 21 MPa
• Maximum pressure: 30 MPa
• Minimum speed: 600 min⁻¹
• Maximum speed: 2000 min⁻¹
• Control: Fixed displacement
• Official catalog weight: approximately 48.0 kg / 106 lb

The official NACHI documentation specifically identifies the 13.3/81.3 cm³/rev configuration and provides its weight and installation dimensions.

IPH-36A-13-80-TT-11

• Brand: NACHI
• Series: IPH
• Pump Type: Double fixed-displacement internal gear pump
• Head-side displacement: 13 cm³/rev
• Shaft-side displacement: 80 cm³/rev
• Mounting method: A, foot mounting
• Auxiliary symbol: TT, screw-in flange kit for individual IN port
• Design number: 11
• Rated pressure: 21 MPa
• Maximum pressure: 30 MPa
• Minimum speed: 600 min⁻¹
• Maximum speed: 2000 min⁻¹
• Control: Fixed displacement
• Base-model official weight for IPH-36A-13-80-11: 70 kg / 154.4 lb
• Final TT configuration weight: not separately stated in the retrieved OEM listing

NACHI America lists the IPH-36A-13-80-11 with a 13 cm³/rev head pump, an 80 cm³/rev shaft pump, A-type mounting and a 70 kg base-model weight.

Common Series Operating Data

• Rated pressure: 21 MPa
• Maximum pressure: 30 MPa
• Minimum speed: 600 min⁻¹
• Maximum speed: 2000 min⁻¹
• Permitted suction pressure: approximately -0.02 to +0.03 MPa
• Pump type: Fixed-displacement double internal gear pump
• Dual-pump output: Two separate displacement sections within one pump assembly
• Important pressure condition: when pressure is simultaneously applied to the head and shaft sides, the applicable pressure limit must be evaluated according to the rated-pressure condition rather than assuming the two pump pressures can be added together.

Key Technical Advantages

1. Axial and Radial Pressure Loading

The IPH series incorporates a patented axial and radial pressure-loading system designed to maintain hydraulic sealing and efficiency as pressure increases. NACHI identifies this design as a key factor behind the series’ high-efficiency operation and pressure capability up to 30 MPa.

2. Modified Involute Short-Tooth Internal Gear Design

The modified involute short-tooth gear profile reduces the pulsation associated with internal gear meshing and contributes to quieter hydraulic operation. This architecture is particularly valuable in machine-tool, industrial automation and other applications where hydraulic noise is a major design concern.

3. Flexible Dual-Displacement Configuration

The double-pump architecture permits different head-side and shaft-side displacement combinations. For example, IPH-24A-6.5-25-T-11 combines 6.5 and 25 cm³/rev, while IPH-36B-13-80-11 combines approximately 13 and 80 cm³/rev. This configuration supports multiple hydraulic circuits without requiring two separate pump drive assemblies.

4. Simple Mechanical Construction

NACHI describes the IPH structure as simple, which helps simplify inspection and maintenance. Compared with more complex variable-displacement architectures, the fixed-displacement internal gear design provides a straightforward mechanical solution where fixed flow characteristics are appropriate.

5. 10D-to-11D Installation Continuity

For service replacement, NACHI states that the newer 11D design is installation-compatible with the previous 10D design. This is particularly important for legacy configurations such as IPH-34B-10-25-10. However, NACHI also specifies that some seal components between IPH-3 and IPH-4 sizes are not fully interchangeable, so complete model verification remains essential.

6. Engineering-Tested Replacement Supply

For replacement units supplied by our engineering team, the pump can be matched against the original model code and tested under simulated operating conditions. The recommended verification points include pressure stability, displacement consistency, leakage performance, noise level, shaft operation and high-speed running behavior.

Application Areas

• Industrial hydraulic power units
• Injection molding and plastic processing machinery
• Hydraulic presses and forming equipment
• CNC machine tools
• Industrial automation hydraulic circuits
• Hydraulic test and power systems
• Mobile machinery auxiliary hydraulic circuits
• Systems requiring two different fixed flow rates from one drive source

Final model selection should always be based on actual required flow, pressure, speed, shaft configuration, port arrangement and mounting dimensions.

Expert Maintenance Tips

1. Maintain Proper Shaft Alignment

The pump should be mounted on a sufficiently rigid base, and the drive alignment should be checked carefully. Excessive eccentricity or angular misalignment can increase bearing and shaft loading and shorten service life.

2. Prime and Bleed the Pump Before Full-Load Operation

Before initial startup, fill the pump with clean hydraulic oil and use low-speed inching or an appropriate air-bleeding procedure to remove trapped air from the pump and hydraulic lines.

3. Avoid Poor Suction-Port Orientation

NACHI specifically warns against installing the suction port toward the bottom of the pump. Correct suction-port orientation helps reduce the risk of inadequate inlet conditions during startup.

4. Review Inlet Piping Above 1800 rpm

When operating above 1800 min⁻¹, NACHI recommends considering separate inlet piping for the head-side and shaft-side pump sections to protect the inlet conditions of the dual-pump system.

5. Verify Legacy 10D Models Carefully

For IPH-34B-10-25-10, do not select a replacement only by external appearance. Verify the full model number, mounting method, displacement combination, shaft, rotation, seal configuration and inlet arrangement. The 11D series is installation-compatible with 10D, but this does not mean every internal component is automatically interchangeable.

Engineering Verification Note

The above specifications are based primarily on NACHI/NACHI America technical catalogs and official product documentation. Where the exact supplied configuration’s mass was not separately published by the OEM, the value has deliberately been marked as not confirmed rather than estimated.

For the four requested models, the most important procurement identifiers are:

• IPH-24A-6.5-25-T-11
• IPH-34B-10-25-10
• IPH-36B-13-80-11
• IPH-36A-13-80-TT-11

The 10 suffix in IPH-34B-10-25-10 should be treated as a legacy design reference and checked against the customer’s existing nameplate before ordering a current -11 replacement