9 Types Of Causes And Treatment Methods For Hydraulic System Failures

Introduction to Hydraulic Systems in Mining Operations

Hydraulic systems serve as the core power transmission system that drives and controls mining equipment. These sophisticated systems enable precise, stable, and efficient operation under extreme load conditions for heavy machinery like excavators, crushers, hoists, and hydraulic supports.

As these systems work relentlessly in harsh mining environments, they’re particularly prone to various failure modes. Understanding these potential issues is crucial for maintaining operational efficiency and preventing costly downtime.

 

Hydraulic System Core Components Overview

Before examining common failures, let’s review the five critical components that make up a typical mining hydraulic system:

1. Power Components: Hydraulic pumps (piston/gear types) that convert mechanical energy into hydraulic energy
2. Actuators: Hydraulic cylinders and motors that transform hydraulic energy into mechanical motion
3. Control Components: Valves (directional, pressure, flow) that regulate system parameters
4. Auxiliary Components: Tanks, filters, coolers, and seals that maintain system integrity
5. Working Medium: Hydraulic oil that transmits energy and provides lubrication

Now that we understand the key components, let’s examine the nine most common failure modes in mining hydraulic systems and their solutions.

 

1. System Running With Loud Noise

• The main noise in the hydraulic system is from the hydraulic pump. Its pressure fluctuation and structural vibration cause the noise of the machine and equipment, such as the phenomenon of suction, the oil suction filter will be blocked locally, and the suction pipe is away from the oil surface. If it is relatively close, this will cause a loud noise from the pump. When this problem occurs, you may need to add enough oil according to the regulations, clean the oil filter, and tighten the connecting screws.
• Valve springs, valve reversal, and poor pressure valves can also cause loud noises. The failure manifests itself in the form of pressure changes. Air entering the hydraulic cylinder will cause system noise and resonance. If cavitation occurs, check whether the oil level and sealing device are normal, and remove the air from the pump.
• In some situations, when one end of the hydraulic system is a valve, and the other end is a large container, it is easy to produce pressure shocks. At this time, the instantaneous pressure peak is many times higher than the normal value, which will cause the vibration of the actuator, normal operation will be affected, and noise will be generated. Such actions often cause wrong actions in some components.

 

2. System Temperature Running Too High

Another common fault of mining machinery hydraulic systems is that the temperature is running too high. Generally speaking, it is normal for the temperature of the machine to increase after a period of time. However, if the high temperature is not controlled, the machine will be damaged, even causing mechanical spontaneous combustion, with serious consequences.

When the system is overheated, check whether there is oil leakage inside and whether the pump is worn. And if there is oil leakage, it should be replaced in time. Also, check whether the pressure setting value of the safety valve is faulty, and set the value in time. When the pump is installed too tightly, it can also overheat the system.

 

3. The System Pressure is Abnormal

Here are some common reasons that may cause abnormal pressure in the system.

• The oil level in the fuel tank is too low, the system pressure is under normal operation, and the component does not move, or the component moves slowly when the actuator is working.
• The opening of the relief valve is damaged, and the setting value of the pressure-reducing valve is low, resulting in insufficient system pressure. If the oil viscosity is too high or too low, the control pressure of the valve is not enough, and the orifice in the valve is blocked.
• The oil temperature is too high, the joint or seal is leaking, the cylinder or motor is severely worn, or the main pump or motor is leaking too much.
• The pump is turning incorrectly, the amplifier is malfunctioning, or the amplifier is tuned incorrectly.
• Motor failure, overflow valve setting value is low, or the pump is blocked or damaged, and the valve fails.

Maintenance Tips

• Calibrate pressure sensors quarterly
• Replace pressure filters every 500 hours
• Monitor the accumulator precharge monthly

While pressure issues affect system performance, unstable operation presents more immediate operational challenges.

 

4. Unstable Operation of The Hydraulic System

When the hydraulic system is unstable, it will slow down or suddenly speed up. In order to prevent this situation from happening, the lubrication conditions should be improved to reduce friction and clean up the stolen goods in time. 

Check whether the oil level is too low and the seal is intact. When the pressure pulse or the system pressure is too low or too large, it is not enough to overcome the external resistance. Check whether the setting value of the overflow valve meets the requirements. If it does not meet the requirements, it should be adjusted in time.

 

5. The Hydraulic System can’t Supply Oil Normally

During the movement of the hydraulic cylinder, when it is braked or reaches the endpoint, the movement of the hydraulic cylinder has large inertia and momentum, which will cause a greater impact when it is suddenly braked or collides. The pressure increases, and then impacts, which increase the hydraulic impact of the system.

When the direction is changed, the program is turned off or turned on instantly, which causes the potential energy to be converted into kinetic energy, and when the kinetic energy is converted into potential energy, an impact occurs.

Solution

Check whether the oil level of the fuel tank is too low and whether there is a leak. If a leak is found, add the oil to the normal position. Check whether the suction pipe and the oil filter are blocked. If the viscosity of the oil is too high, the oil tank can be drained and replaced with a lower viscosity oil. If a one-way pump is used in the hydraulic system, there may be a problem with the steering of the pump. At this time, you can correct the wiring and then change the direction.

 

6. Leakage of The Hydraulic System

Leakage of the hydraulic systems is one of the common faults of hydraulic systems. The surface geometric accuracy of the valve should be checked in time, and whether the concentricity of the valve is sufficient. If the casting parts have pores or cracks, the parts should be replaced, such as due to aging, or if the seal is not tight, the seal should be replaced. Check whether the oil pipe joints are loose. If they are loose, they should be tightened in time, and attention should be paid to check whether they are broken.

 

7. Small System Traction

When the hydraulic system has a small traction failure, it is generally necessary to re-check the safety valve of the system and make timely adjustments to the incorrect places; check whether the fuel tank is leaking, repair it, and fill it up in time. In addition, the cooling water volume and water pressure need to be adjusted to reach the rated value.

 

8. The Working Structure is Unstable

The working structure of the hydraulic system is a relatively complicated process. Therefore, when it is unstable, it should be inspected and repaired in time to avoid unnecessary losses. The main manifestations when the working structure of the hydraulic system is unstable are sudden acceleration or gradual slowing down, abnormal beating, and other phenomena.

• The lubrication effect is not good, and the resistance is increased. When this situation occurs, the lubricant should be added in time to remove debris to ensure the normal operation of the work.
• During work, the oil pump sucks oil, and the air enters the working system. It is necessary to check the oil level and tightness in time to ensure that the oil level reaches the standard level.
• The system has no pressure and can not restrain the resistance.

 

9. Other Common Faults

• If the motor shaft does not rotate when the circuit or power supply is disconnected, and if the component fails, the motor will turn incorrectly, causing the pump to reverse.
• The internal assembly quality of the hydraulic pump is poor, and the plunger head is prone to getting stuck. The oil temperature is too high, causing some parts to overheat and deform.
• When the oil level of the fuel tank is too low, the pump will not suck oil.
• At the oil passage, there is a blockage, and the oil is dirty.
• Due to the inside of the pump, the sliding parts are severely worn, and the amount of oil pumped out is obviously insufficient.

The construction principle of liquid equipment is different from other equipment, and it is relatively more complicated, so the diagnosis and treatment of its faults are difficult. When dealing with the problem, we must first systematically understand the failure phenomenon, list the possible causes, and try to solve the problem as soon as possible, and resume production according to the principle of easy first and difficult.

 

Conclusion: Building a Comprehensive Maintenance Strategy

Effective hydraulic system management requires:

1. Proactive Monitoring:
   • Implement condition-based maintenance
   • Establish baseline performance metrics
2. Systematic Troubleshooting:
   • Develop a fault tree analysis for common issues
   • Create quick-reference diagnostic flowcharts
3. Continuous Improvement:
   • Document all failures and solutions
   • Analyze failure trends quarterly
4. Training Investment:
   • Certify maintenance staff in hydraulic diagnostics
   • Conduct annual refresher courses