VDN-1B-2A3-U-11WC37 NACHI Variable Vane Pump

Product Overview

The VDN-1B-2A3-U-11WC37 belongs to the NACHI-FUJIKOSHI VDN-1B variable vane pump platform.

NACHI’s official hydraulic documentation identifies VDN-1B as the pump size used in the UVN Series Variable Volume Vane Uni-pump. NACHI’s official hydraulic catalog also lists VDS, VDR, VDC and UVN as part of its variable-displacement vane pump portfolio.

The official UVN documentation confirms that the VDN-1B platform can be configured as a variable-volume vane pump with different pressure-adjustment ranges and flow configurations. Depending on the complete UVN configuration, the documented maximum no-load flow at 1800 min⁻¹ can reach 29 L/min or 46 L/min, while pressure adjustment ranges include 1.5–4.0 MPa, 3.5–6.0 MPa and 5.5–8.0 MPa.

However, these UVN specifications should not be presented as the direct specifications of the old VDN-1B-2A3-U-11WC37 model. The exact legacy model number has been found in industrial-market records, but a current NACHI official technical page providing its complete standalone displacement, pressure, speed and mass data was not located during verification.

For this reason, unsupported numerical specifications are deliberately excluded. For retrofit applications, the complete original model, mounting dimensions, shaft geometry, port arrangement and control configuration should be verified before replacement. Replacement units can be subjected to 100% simulated operating-condition testing before shipment.

Technical Specifications

Primary Model: VDN-1B-2A3-U-11WC37

• Brand: NACHI / NACHI-FUJIKOSHI
• Model: VDN-1B-2A3-U-11WC37
• Product Type: Variable Volume Vane Pump
• Pump Size: VDN-1B
• Pump Architecture: Variable-displacement vane pump
• Series Association: VDN-1B is officially identified as the pump size used in the NACHI UVN Uni-pump platform.
• Control Principle: Variable displacement; the exact control mechanism for this legacy model should be verified from the original technical documentation
• Geometric Displacement: Not stated for this exact legacy model in the NACHI official sources located for this review
• Rated Pressure: Not directly verified for the complete VDN-1B-2A3-U-11WC37 model
• Peak Pressure: Not directly verified
• Maximum Speed: Not directly verified for this complete legacy model
• No-Load Flow: Should not be borrowed from the current UVN-1B data without confirming the actual model configuration
• Weight: Not directly verified
• Design / Version Code: 11WC37; a complete character-by-character interpretation was not found in current NACHI public English documentation and is therefore not asserted
• Housing Material: Not independently verified for the exact legacy model
• Rotation: Not independently verified
• Mounting: Not independently verified
• Hydraulic Fluid: Must follow the original machine specification and NACHI documentation applicable to the actual pump

Officially Confirmed VDN-1B / UVN Reference Data

NACHI’s official UVN documentation confirms:

• Pump Size 1 = VDN-1B
• Pump Type = Variable Volume Vane Pump
• The documented UVN configurations include pressure adjustment ranges of 1.5–4.0 MPa, 3.5–6.0 MPa and 5.5–8.0 MPa
• Certain UVN-1B configurations specify up to 29 L/min at 1800 min⁻¹
• Larger UVN-1B configurations specify up to 46 L/min at 1800 min⁻¹.

These are official UVN-1B platform reference values, not guaranteed direct ratings for VDN-1B-2A3-U-11WC37.

Key Technical Advantages

1. Variable-Displacement Vane Pump Architecture

VDN-1B belongs to NACHI’s variable-volume vane pump technology. Compared with fixed-displacement vane pumps, variable-volume architecture allows pump output to be adjusted according to system requirements, helping reduce unnecessary hydraulic flow under partial-load conditions.

NACHI officially uses VDN-1B as the pump size for the UVN Series Variable Volume Vane Uni-pump.

2. Adjustable Pressure and Flow Characteristics

NACHI’s official UVN documentation provides several pressure-adjustment ranges, including:

• 1.5–4.0 MPa
• 3.5–6.0 MPa
• 5.5–8.0 MPa

This demonstrates the flexibility of the VDN-1B platform for industrial systems requiring controlled pressure and flow behavior.

3. Focus on Efficient and Quiet Operation

NACHI’s official variable vane pump documentation emphasizes mechanisms designed to reduce power losses and operating noise. Its VDS literature, for example, describes reduced loss power, improved port geometry and bearing arrangements intended to provide quieter operation with reduced vibration in higher-pressure operation.

These characteristics should be regarded as design-family information rather than as a guaranteed performance rating for the specific legacy VDN model.

4. Compact Industrial Hydraulic Platform

NACHI uses VDN-1B as the pump size for its UVN Uni-pump platform and combines the pump with a dedicated drive motor in a compact package.

This architecture is useful in industrial machines where hydraulic power must be integrated into a limited installation space.

5. Complete Model Identification for Retrofit

The complete VDN-1B-2A3-U-11WC37 designation contains substantially more identification information than the basic VDN-1B frame size.

For retrofit work, the correct engineering approach is to verify:

VDN-1B + 2A3 + U + 11WC37

together with the original shaft, mounting and port configuration.

6. Practical for Legacy Replacement Engineering

Legacy NACHI hydraulic equipment may no longer be easily searchable through current product databases. In these cases, interchangeability depends on:

Mounting geometry + shaft dimensions + displacement + pressure response + port layout + control architecture.

A properly engineered replacement should therefore be based on physical verification and functional testing rather than external appearance alone.

Application Areas

Based on NACHI’s variable vane pump and UVN product positioning, VDN-1B platform pumps are associated with industrial hydraulic applications such as:

• Machine tools
• Metalworking equipment
• Hydraulic power units
• Automated production machinery
• Injection and forming equipment
• Press machinery
• Hydraulic clamping systems
• Precision industrial machinery
• General industrial hydraulic systems

NACHI includes variable vane pump families within its standard industrial hydraulic equipment portfolio and specifically identifies VDN-1B as the pump size used for the UVN Uni-pump.

Expert Maintenance Tips

1. Verify the Complete Model Number

For:

VDN-1B-2A3-U-11WC37

the complete designation should be retained during replacement. Ordering only by “VDN-1B” is insufficient.

The exact model has been documented in industrial-market records, but third-party listings should not replace the original NACHI engineering documentation for critical specifications.

2. Do Not Transfer UVN Ratings Directly to the Legacy VDN Model

This is an important engineering distinction.

NACHI officially confirms:

UVN Pump Size 1 = VDN-1B

but this does not mean:

UVN-1A-2A3 = VDN-1B-2A3-U-11WC37

The two designations belong to different product-identification levels, so pressure, flow and motor specifications must be verified separately.

3. Inspect the Variable Control Mechanism

For symptoms such as:

• unstable flow
• abnormal pressure rise
• excessive unloaded flow
• failure to reduce flow at pressure

inspect the displacement-control mechanism, adjustment spring and associated hydraulic control passages rather than replacing vane components alone.

4. Protect the Suction Circuit

Variable vane pumps are sensitive to poor inlet conditions. Keep suction piping short and low-restriction and prevent air ingress.

NACHI’s official UVN installation guidance specifies suction-line velocity below 2 m/s and defines a specified suction-pressure range at the pump inlet.

5. Install with a Rigid, Horizontal Shaft Arrangement

NACHI’s official UVN installation instructions require a sufficiently rigid mounting base and installation with the pump shaft horizontal.

This requirement should also be respected when replacing legacy VDN pumps.

6. Control Hydraulic Contamination

Inspect:

• Hydraulic-fluid cleanliness
• Filter condition
• Fluid viscosity
• Oil temperature
• Air entrainment
• Rotary-group wear

Contamination or unsuitable fluid conditions can negatively affect vane-pump clearances and flow stability.

7. Commission Gradually

After replacement, progressively check:

No-Load Flow → Pressure Build-Up → Pressure Stability → Variable Response → Full-Load Operation

Persistent abnormal noise, unstable flow or failure to achieve the expected pressure response should be investigated before full-load operation.