Applications and Maintenance Guidelines of Bladder Accumulator NXQA-6.3/31.5-L-Y

2026-08-21

Structure and Operating Principle The interior of the accumulator NXQA-6.3/31.5-L-Y is divided into two chambers by a bladder: the inside of the bladder is filled with high-pressure nitrogen, while the outside connects to the hydraulic oil circuit.

System Pressure Increases: Hydraulic oil enters the outer chamber of the accumulator, compressing the bladder and nitrogen gas to store energy.
System Pressure Decreases: The nitrogen gas expands, releasing stored fluid back into the hydraulic circuit to replenish oil, maintain pressure, absorb shocks, and compensate for leakage.
Type A Structure: Features a small port design with a relatively narrow fluid port diameter. It is ideal for pressure maintenance, leakage compensation, and pressure pulsation absorption, but unsuitable for high-flow, rapid-discharge conditions.

Applications

Power Plant Equipment: Used in coal mill hydraulic stations, steam turbine governing oil systems, and adjustable-blade axial fan actuator circuits for maintaining pressure and compensating for internal leakage, preventing control valve disturbances caused by pressure loss.
Metallurgical Heavy Hydraulic Systems: Used in pressure-holding clamping circuits and for short-term emergency oil supply.
Construction Machinery: Used to cushion mechanical shocks and absorb pressure pulsations.
General Hydraulic Stations: Used to compensate for valve block leakage, reducing the frequency of oil pump start-stops.

Key Installation and Maintenance Points

Installation: Install vertically with the oil port facing downward; mounting with the oil port facing upward is strictly prohibited. Secure using clamp supports. Welding, drilling, or machining the shell is strictly forbidden, as it compromises the safety performance of the pressure vessel.
Gas Medium: Only high-purity nitrogen is permitted. Using oxygen or compressed air is strictly prohibited due to explosion risks.
Pre-charge Pressure: Pre-charge pressure must be inspected and adjusted only when the accumulator is fully depressurized (oil chamber pressure at zero).
Inspection Anomalies: Frequent oil pump start-stops, sluggish actuator movement, or shortened system pressure-holding times typically indicate nitrogen leakage. Large amounts of air bubbles in the oil reservoir indicate bladder damage, requiring immediate shutdown and replacement of the bladder assembly.
Maintenance Cycle: Check nitrogen pre-charge pressure every 6–12 months. Bladders should generally be replaced every 1–2 years depending on operating conditions.
Safety Provision: The system must be equipped with a relief valve, with the set pressure not exceeding the accumulator’s nominal pressure of 31.5 MPa.