Precautions during the installation and startup of the hydraulic system

Precautions during the installation and startup of the hydraulic system

With the continuous development of hydraulic technology and the continuous improvement of the reliability of hydraulic components, hydraulic transmission technology has been widely applied, and its installation and start-up have also received increasing attention. Taking the road roller system as an example, here are a few points to note regarding the installation and startup of the hydraulic system:

I. Installation and connection of the System

Before installing the system, carefully inspect the pump and motor as well as all system components, including: oil tank, pipelines, valves, joints, radiators, etc., to ensure that all components are undamaged and free from contamination. There should be corresponding measures to maintain the connection oil ports. When installing, attention should be paid to the installation rules of each component, such as the directionality of pumps, motors, valves, etc. When connecting rubber hoses, a certain tensile allowance should be left, and the rubber hoses should not be subjected to torsional forces, etc. All the connections of the system pipelines must be sealed reliably without any leakage. The tightening torque at the oil port end of the threaded connection should comply with the recommended standard. If it is too tight, the rubber sealing ring may be damaged; if it is insufficient, the sealing ring may not be able to fit the end face tightly, both of which may cause leakage. Flange assemblies should be used in combination. Flange pressure plates of different groups are prone to cause the O-rings to not fit tightly, which may lead to leakage.

More than 70% of the faults in the hydraulic system are caused by oil contamination. During the installation process, after the original sealing end covers of each component are opened, the pipelines should be directly connected. If there is a special need to disconnect, all exposed oil ports should be sealed to prevent foreign objects from entering the components and causing contamination.

2. The quality and cleanliness of the oil and the addition of the oil

Since using oil that does not meet the requirements will cause damage to components and systems, it is essential to use hydraulic oil with performance parameters that conform to the recommended values, especially not using hydraulic oil that has already been used. One more point to note is that newly filled barrel oil does not meet the system's cleanliness requirements and cannot be directly added to the system. When new hydraulic oil is added to the hydraulic system, it needs to be filtered through an oil filter or a filter trolley to meet the cleanliness requirements for system startup. Before starting, hydraulic components such as pumps and motors should be filled with as clean hydraulic oil as possible. Do not rely on the oil to fill in by yourself. Add as much clean hydraulic oil as possible to the hydraulic oil tank. If it is a connected split oil tank, install oil filling ports with air filters on both sides of the tank or install an oil filling port on one side of the tank and a vent plug on the other to ensure smooth oil filling.

Iii. Initial Startup Requirements of the System

Before starting the commissioning, install a pressure gauge of an appropriate range at the oil replenishment pressure measurement port to detect the oil replenishment pressure during the start-up commissioning process.

When starting the commissioning, first disconnect the input control signals of the pump (mechanical connecting rods, hydraulic control circuits, electrical control plugs, etc.) to ensure that the pump is in the neutral position. Take necessary measures to remove the system load (lift the main unit to lift the drive wheels off the ground, disconnect the motor load connection, etc.). Start the engine at the lowest possible speed until the fuel pressure is established. The air in the system can be discharged through the pressure gauge hole on the motor valve block. After the fuel replenishment pressure is established, increase the engine to the rated speed and then measure the fuel replenishment pressure value. If the fuel replenishment pressure does not meet the requirements, the engine should be turned off immediately, the cause identified and resolved. If the fuel replenishment pressure is normal, turn off the engine, connect the control signal of the pump, and then restart the engine to check whether the neutral state of the pump is good. After the above steps are completed, the engine is increased to the rated speed, and control signals are input to the pump to make the system start working as slowly as possible. Check the forward and reverse working conditions of the system. In a typical system configuration, when the system is out of the neutral position and operates in both forward and reverse directions, the fuel replenishment pressure value will slightly decrease. Let the system alternate between forward and reverse directions continuously and slowly for at least five minutes. Then turn off the engine, remove the pressure gauge and tighten the pressure measurement joint cap.

During the system startup process, some oil will remain in the pipelines and the casing. At this time, check the oil level in the oil tank. If necessary, add oil to the specified value. If there are many bubbles in the oil, wait for them to disappear and then start the engine again. Let the system alternate between forward and reverse operation for a few minutes, and then turn off the engine. If necessary, this process should be repeated many times until the bubbles completely disappear. Finally, inspect all the pipelines and joints to ensure there is no leakage or looseness, and make sure that no water or other impurities enter the fuel tank.

The above steps can effectively ensure the reliability of the hydraulic system during the installation and start-up process, enabling the entire machine to enter the commissioning in a good state.