Trouble shooting of accumulator

Shanghai Siken Industries Inc.

Web: www.siken-inc.com

When the pressure holding time is short or compensation fails, the usual causes are insufficient pre-charge pressure around the accumulator or a maximum working pressure that is set too low. Rapid injection or expansion failures are typically caused by excessively high dynamic pressure combined with a low maximum working pressure of the accumulator. In practice, most of these problems occur when the first two factors appear together.

If the accumulator fails to reduce hydraulic shock or absorb pressure pulsations, the primary reason is usually that the pre-charge (recovery) pressure is too low.

Recommended Troubleshooting Approach

1. Immediate pressure restoration First, restore the correct nitrogen pre-charge pressure in the accumulator and top up the hydraulic fluid if necessary.

2. Identify the root cause Once basic pressure is restored, determine the exact source of the fault so that it can be corrected properly.

Possible Causes of Abnormal Pressure

• Low pressure may result from:

• Pre-charge pressure set too low

• Insufficient gas charge

• System leakage

• High pressure may result from:

• Pre-charge pressure set too high

• Incorrect system pressure settings

• Environmental or temperature effects

When the maximum working pressure of the accumulator is abnormal:

• First restore the correct maximum working pressure.

• If the pressure remains too low, check the hydraulic pump for faults, cavitation, or incorrect pressure regulation.

• Inspect pressure relief valves and related control valves for improper adjustment or malfunction.

• Verify that the overall system pressure and the accumulator’s maximum working pressure are properly matched. A large mismatch can cause the accumulator pressure to become either too high or too low.

Checking for Component Leakage

If internal leakage of hydraulic components is suspected, focus on the main components connected to the accumulator circuit:

• Control valves

• Directional valves

• Hydraulic cylinders

Common leakage points include:

• Poor sealing between valve spool and seat

• Stuck or worn valve spools

• Damaged seals creating excessive clearance

Systematically isolate and monitor each component to locate the leak. Once identified, disassemble, inspect, and repair or replace the faulty part.

Priority of Fault Sources

For less common issues related to emergency pressure or abnormal maximum working pressure, the possible causes can be ranked as follows:

1. Incorrect pre-charge or maximum working pressure of the accumulator (easiest to check and correct)

2. External or internal leakage of neighboring components

3. Component leakage that is difficult to locate and repair (these cases are also the most critical because uncontrolled leakage can be hazardous)

Correct diagnosis and timely correction of the pre-charge pressure and system settings usually resolve the majority of accumulator-related faults.