Inspection and elimination of hydraulic system faults

When a hydraulic system malfunctions, it is not easy to identify the cause and it is difficult to troubleshoot. Here, some experiences and methods accumulated in the work are summarized for reference.

Five basic methods for troubleshooting hydraulic systems:

Look, smell, touch, cut and sniff

I. Look: What to see.

Check if the system configuration is normal, including: pumps, valves, actuating elements, working oil, oil filters, radiators, etc.

2. Check the speed (flow rate) : Observe whether there are any abnormal phenomena in the movement speed of the actuator;

3. Check the pressure: Observe the magnitude and fluctuation of the pressure values at each pressure measurement point in the hydraulic system.

4. Check the oil: Observe whether the oil volume is appropriate, whether it is clean, whether it has deteriorated, and whether there are bubbles in the oil, etc.

5. Check for leakage: Inspect whether there is any seepage, dripping or oil sludge at the joints of the hydraulic pipelines, the junctions of the valve plates, the end covers of the hydraulic cylinders, and the extensions of the hydraulic pump shafts.

Two. Smell: What to hear.

1. Listen to the noise: Determine whether the sound heard is noise, where the source of the noise is, and whether it is a hydraulic component such as a hydraulic pump, motor, or valve, or the system's pipelines or the working mechanism connected to the components.

2. Listen to the impact sound: Listen to whether the impact sound of the system is normal.

The duration of the impact sound: When the hydraulic valve changes direction, there is an impact or an inexplicable sound.

The regularity of impact sounds: rhythmic or irregular.

3. Listen for leakage sounds: Check if there are any faint, continuous sounds in the oil circuit.

4. Listen for knocking sounds: Check if there are knocking sounds when the hydraulic components are in operation.

5. Listen to the reports from relevant personnel.

Iii. Touch: Feel what.

1. Feel the temperature rise: Touch the surface of the moving parts with your hand to check if they are hot.

2. Feel the vibration: Check if there is any vibration phenomenon.

3. Crawling: Feel if there is any "crawling" phenomenon on the moving parts.

4. Feel the tightness: Check the tightness of the threaded connection.

5. Check the airtightness: For areas that are not visible, inspect for any oil leakage.

Four. Cut: Use a pressure gauge for judgment.

1. Whether the pressure values at all locations are normal: the oil suction and discharge of the pump, the oil intake and discharge of the motor, the oil pressure in both chambers of the cylinder, the working pressure and control pressure of the valve, etc.

2. Whether there are fluctuations in pressure and whether the fluctuations are within the design range.

V. Judge by smell.

Smell the oil to see if it has gone bad or smelly.

Old cars: After long-term use, the oil components will deteriorate and develop strange odors such as stench.

New car: Check if the refueling operation is correct to prevent adding the wrong fuel.

2. Smell the entire system to see if there is any strange odor and where it comes from.