NXQ-AB-63/31.5-L-Y 63L 31.5MPa Bladder Accumulator

Product Overview

The NXQ-AB-63/31.5-L-Y is a 63-liter national-standard bladder accumulator designed for high-pressure hydraulic systems.

This model belongs to the NXQ series defined within the Chinese pressure-vessel standard framework. According to GB/T 20663-2006, NXQ bladder accumulators are classified by structure, nominal volume, design pressure, connection type and working medium. The standard includes nominal volumes from 0.4 L to 250 L and design-pressure classes including 31.5 MPa.

The model code can be interpreted as:

• NXQ — bladder accumulator
• AB — large-opening structure
• 63 — 63 L nominal volume
• 31.5 — 31.5 MPa nominal pressure
• L — threaded hydraulic connection
• Y — hydraulic oil

Public NXQ technical documentation confirms the A/AB structural distinction and lists the NXQ-AB-63/31.5-L-Y configuration among standard products.

This is not a proprietary Parker, HYDAC, Rexroth or Danfoss model. Because several Chinese manufacturers produce NXQ accumulators according to the same national-standard designation, the complete model code, manufacturer, connection dimensions and actual vessel nameplate must be verified before direct replacement.

Our replacement units are manufactured around the applicable NXQ standard requirements and the customer’s original accumulator configuration, with 100% simulated operating-condition testing covering pressure integrity, sealing, bladder performance and charge/discharge behavior.

Technical Specifications

NXQ-AB-63/31.5-L-Y

• Product Type: National Standard Bladder Accumulator
• Model: NXQ-AB-63/31.5-L-Y
• Series: NXQ
• Structure: AB Type / Large Opening
• Nominal Volume: 63 L
• Nominal Pressure: 31.5 MPa
• Pressure Equivalent: 315 bar
• Hydraulic Connection: Threaded
• Connection Code: L
• Working Medium: Hydraulic Oil
• Gas Medium: Nitrogen
• Accumulator Type: Bladder / Gas-Liquid Separation
• Applicable Standard: GB/T 20663-2006
• Design Pressure Class: 31.5 MPa
• Displacement: Not applicable
• Rotational Speed: Not applicable

Public technical documentation also lists the 31.5 MPa NXQ family in 63 L and larger capacities, with threaded and flanged connection options.

Engineering Interpretation of the Model Code

NXQ

Identifies the standard bladder-accumulator product family.

AB

Identifies the large-opening configuration.

• A = Small opening
• AB = Large opening

This structural distinction is important when matching hydraulic flow requirements and replacement parts.

63

Indicates a 63-liter nominal accumulator volume.

Nominal volume is the geometric gas/fluid vessel capacity; the usable hydraulic volume during operation is determined by the pressure ratio and nitrogen pre-charge.

31.5

Indicates a 31.5 MPa nominal pressure class.

L

Indicates a threaded hydraulic connection.

Y

Indicates hydraulic oil as the working medium.

Therefore:

NXQ-AB-63/31.5-L-Y = 63 L / 31.5 MPa / AB structure / threaded connection / hydraulic oil.

Key Technical Advantages

31.5 MPa High-Pressure Design

The 31.5 MPa pressure class provides a high-pressure storage solution for demanding industrial hydraulic circuits. GB/T 20663 explicitly defines 31.5 MPa as one of its standard design-pressure classes.

63 L Energy Storage Capacity

The 63-liter configuration is intended for larger hydraulic energy-storage and transient-flow requirements than compact accumulator sizes.

Actual usable oil volume depends on:

• Minimum operating pressure
• Maximum operating pressure
• Nitrogen pre-charge
• Temperature
• Gas compression process
• Required hydraulic cycle

AB Large-Opening Architecture

The AB configuration uses the large-opening structure defined by the NXQ model system. It should not automatically be substituted with an A-type accumulator simply because the volume and pressure ratings appear identical.

Gas-Liquid Separation

The bladder separates nitrogen from hydraulic fluid. Hydraulic pressure compresses the nitrogen during charging, while gas expansion returns stored hydraulic fluid to the circuit when system pressure or flow demand changes.

Multi-Function Hydraulic Energy Management

NXQ accumulators can be used for:

• Energy storage
• Shock absorption
• Pulsation damping
• Leakage compensation
• Emergency energy supply
• Pressure maintenance
• Flow peak support

These functions are documented in public NXQ accumulator technical literature.

Standardized Engineering Selection

GB/T 20663 standardizes the basic NXQ model-code structure, pressure classes, nominal volumes and connection categories. This provides a systematic approach to selecting and identifying replacement accumulators.

Application Areas

• Large Hydraulic Power Units
• Hydraulic Presses
• Steel Processing Equipment
• Metal Forming Machinery
• Mining Equipment
• Construction Machinery
• Oilfield Equipment
• Petroleum Machinery
• Large Machine Tools
• Industrial Hydraulic Systems
• Hydraulic Test Systems
• Emergency Hydraulic Power Circuits
• Pressure Pulsation Damping Systems

Expert Maintenance Tips

Calculate Nitrogen Pre-Charge Correctly

The 31.5 MPa rating is not the nitrogen pre-charge pressure.

Pre-charge must be calculated according to the accumulator function and system operating range. Public NXQ technical guidance indicates that, for energy-storage applications, pre-charge should remain below approximately 90% of the minimum operating pressure, with final selection based on the actual pressure cycle.

Use Nitrogen Only

Use N₂ nitrogen for charging the gas side.

Do not use:

• Oxygen
• Compressed air
• Flammable gas

NXQ technical guidance explicitly prohibits these alternatives.

Provide Independent Mechanical Support

A 63 L high-pressure accumulator should be mechanically secured using suitable clamps and brackets rather than relying on connected hydraulic piping for support.

Depressurize Before Service

Before maintenance:

Isolate → Depressurize → Verify Zero Pressure → Service

An accumulator may retain substantial stored hydraulic energy even after the hydraulic pump has stopped.

Inspect the Bladder

Inspect the bladder and gas-side components when:

• Pre-charge pressure falls unexpectedly
• Pressure pulsation increases
• Stored-energy performance decreases
• Hydraulic temperature rises
• Charge/discharge response changes
• Gas leakage is detected

Do Not Mix A and AB Configurations

An NXQ-AB-63/31.5-L-Y should not be replaced by an A-type unit without verifying the hydraulic opening, connection and flow requirements. The A and AB configurations represent different structural designs.

Perform Full Replacement Testing

For a replacement 31.5 MPa accumulator, recommended verification includes:

• Pressure-vessel inspection
• Hydraulic pressure testing
• Leakage testing
• Gas-valve sealing
• Bladder integrity
• Nitrogen pre-charge verification
• Connection dimensional inspection
• Charge/discharge simulation
• Final safety inspection

Our replacement units can undergo 100% simulated operating-condition testing before shipment to verify pressure integrity, sealing performance and dynamic accumulator behavior.