Precautions for use of 4WEH16 electro-hydraulic reversing valve

4WEH16 electro-hydraulic reversing valve is a key control element widely used in hydraulic systems. It is used to switch the flow direction of hydraulic oil, thereby controlling the movement direction of the actuators (such as hydraulic cylinders, hydraulic motors). Its use needs to be combined with the characteristics of the hydraulic system, electrical control logic and environmental conditions. The following are detailed precautions for use, covering five major links: installation, commissioning, operation, maintenance and troubleshooting:

1. Check and prepare before installation

1. Confirmation of environmental adaptability

• Temperature range: Ensure that the working environment temperature is between -20℃ and +80℃ (if it exceeds the high-temperature or low-temperature resistant model, such as adding a heater or cooling device).

• Humidity control: Avoid long-term use in humid environments with humidity >85%, and prevent short circuit or corrosion of electrical components (such as solenoid coils).

• Dust protection requirements: The installation position should be kept away from dust sources, or a dust cover should be installed (protection level is recommended to be IP65 or above) to prevent valve core from being stuck or seal wear.

2. Hydraulic system matching verification

• Pressure level: Make sure that the maximum working pressure of the system does not exceed the rated pressure of the valve (4WEH16 is usually 31.5MPa). If it is overpressure, an overflow valve or pressure reducing valve must be installed.

• Flow matching: Select the pump displacement according to the nominal flow rate of the valve (such as 160L/min) to avoid valve port impact or noise due to excessive flow (allowed flow fluctuations ≤±10%).

• Oil cleanliness: Hydraulic oil must reach NAS1638 Level 7 or ISO 4406 18/16 standards. Before installation, use a precision oil filter (filtration accuracy ≤5μm) to filter the oil.

3. Valve body and accessories inspection

• Appearance damage: Check the valve body, solenoid, and bottom plate for cracks, deformation or oil stains, and pay special attention to the processing accuracy of the valve core hole and sealing groove (surface roughness Ra≤0.8μm).

• Model check: Confirm that the valve model (such as 4WEH16J5X/6EG24NETZ5L) is consistent with the system requirements, including parameters such as diameter (16mm), control method (electro-hydraulic), voltage level (24V DC).

• Accessories integrity: Check whether the matching O-rings, dust rings, electromagnet plugs, etc. are complete, and confirm that the material is compatible with oil (such as nitrile rubber is suitable for mineral oil).

2. Installation and wiring specifications

1. Key points for mechanical installation

• The oil inlet (P) is connected to the pump outlet, the oil return port (T) is connected to the oil tank, and the working oil outlet (A/B) is connected to the actuator.

• The pipe bending radius is ≥5 times the pipe diameter, avoiding oil impact or pressure loss due to sharp bends (local pressure loss ≤0.5MPa).

• Seal the connection with an O-ring to avoid excessive force when tightening the joints.

• Installation direction: The valve body should be installed horizontally (the solenoid is vertically upward) to avoid deviation of the valve core due to its own weight (the allowable inclination angle is ≤5°).

• Fixing method: Use M12 bolts to fix the valve on the bottom plate or integrated block, and the tightening torque is 80-100N·m (a torque wrench is required) to prevent loosening caused by vibration.

• Pipe connection:

2. Electrical wiring specifications

• The outer diameter of the cable is ≥φ6mm, and the length is ≤5m (too long, relays need to be installed to extend the signal transmission distance).

• The terminals are wrapped with an insulating sleeve to avoid short circuit or leakage (insulation resistance ≥1MΩ).

• The solenoid plug needs to be tightened and fixed with a locking nut to prevent vibration from falling off.

• Voltage matching: Make sure that the power supply voltage is consistent with the rated voltage of the solenoid (such as 24V DC), and the voltage fluctuation range is ≤±10% (otherwise, a voltage regulator needs to be installed).

• Correct polarity: DC electromagnets need to strictly distinguish between positive and negative poles, and inverse connection will cause the coil to burn (a multimeter can be used to detect the coil resistance, usually several tens of ohms).

• Wiring protection:

3. Debugging and operation monitoring

1. Initial debugging steps

• Start the pump and slowly increase the pressure to 50% of the system pressure to observe whether there is any leakage in the valve body (oil leakage amount ≤1 drop/min).

• Gradually increase the pressure to the rated pressure, check whether the movement direction of the actuator (such as the hydraulic cylinder) is consistent with the control signal and whether the speed is stable.

• Power on the solenoid (24V DC) and use an oscilloscope to detect the coil current waveform (rise time ≤10ms, no oscillation or overshoot).

• Observe the valve core operating time (usually 20-50ms). If it is too long, check the solenoid suction force or spring preload force.

• Manual operation test: When the power is off, manually push the valve core with a special tool to confirm that the valve core is moved flexibly (resistance ≤10N), without jamming or abnormal noise.

• Electrical signal test:

• Hydraulic system linkage test:

2. Monitoring parameters during operation

• The oil temperature is controlled between 40-60℃ (too high will accelerate the aging of the seal, too low will lead to excessive oil viscosity).

• If the oil temperature exceeds 80℃, the cooler efficiency or the pump volume efficiency must be checked.

• Pressure monitoring: Use a pressure gauge to detect the pressure of port P and port A/B to ensure that the pressure fluctuates ≤±5% of the rated pressure (such as the 31.5MPa system fluctuations ≤±1.575MPa).

• Temperature control:

• Noise analysis: During normal operation, noise is ≤75dB (measured 1m from the valve). If the noise suddenly rises, it may cause valve core wear or cavitation.

3. Load adaptability adjustment

• Light load start: When the system starts, run at no-load or low load for 5-10 minutes first, and wait until the oil is fully lubricated before loading to the rated value.

• Impact load treatment: If the actuator frequently starts and stops or bears impact load, an accumulator must be installed at the A/B port of the valve (the precharge pressure is 60%-80% of the system pressure) to absorb pressure shock.

• Overload protection: Install an overflow valve at the pump outlet (the set pressure is 5%-10% higher than the maximum pressure of the system) to prevent damage to the valve body due to overpressure.

4. Maintenance and maintenance points

1. Daily inspection items

• Leak inspection: Observe oil stains at each connection of the valve body and the bonding surface of the solenoid and valve body every day. If leakage is found, tighten the joint or replace the seal.

• Oil status: Observe the oil color through the oil detection window (normally light yellow, black or emulsified, and need to be replaced immediately).

• Temperature record: Record the oil temperature change trend. If the oil temperature exceeds 65℃ for 3 consecutive days, the efficiency of the cooling system or pump needs to be checked.

2. Regular maintenance content

• Clean the surface of the solenoid with oil stains (wipe it with a non-woven fabric dipped in a small amount of hydraulic oil).

• Detect the coil insulation resistance (≥1MΩ), and if it is lower than the standard value, it needs to be dried (dried in an oven with 60℃ for 4 hours).

• Seal replacement: Replace O-ring and dust-proof ring every 2000 hours of operation (recommended to use fluoroelastic material, with a temperature resistance range of -40℃ to +200℃).

• Valve spool cleaning: Disassemble the valve body every 5,000 hours of operation, clean the valve spool and valve sleeve with hydraulic oil (gas or alcohol is prohibited), and check the fitting gap (standard value 0.01-0.03mm).

• Electromagnet maintenance:

3. Long-term disabling protection

• Anti-rust treatment: Flush the inside of the valve body with hydraulic oil before discontinuing, and apply anti-rust oil (such as WD-40) into the valve core hole.

• Electrical protection: Disconnect the solenoid power supply, wrap the valve body with a dust cover, and store it in a dry and ventilated place (relative humidity ≤60%).

• Regular start: If the deactivation time exceeds 3 months, power must be turned on once a month (10 minutes each time) to prevent the valve core from getting stuck.

5. Common faults and solutions

1. The valve core does not move

• Check the electrical circuit (use a multimeter to detect the coil resistance, if it is ∞, the coil will be opened).

• Disassemble the valve body and clean the valve core with hydraulic oil (if the valve core is severely stuck, you need to replace it).

• Replace the spring (the spring preload must meet the design value, usually 20-30N).

• Possible reasons: the solenoid is not energized, the coil is burned, the valve core is stuck, and the spring is broken.

• How to deal with it:

2. Serious leak

• Replace the seal (note the installation direction, the O-ring cutout must be facing the hydraulic side).

• If the valve body is cracked, it needs to be returned to the factory for repair or replaced with a new valve.

• Retighten the connection bolts (torque values ​​refer to installation specifications).

• Possible causes: ageing seals, cracks in the valve body, loose connecting bolts.

• How to deal with it:

3. Slow movements

• Replace low viscosity hydraulic oil (such as 46# anti-wear hydraulic oil).

• Repair or replace the valve core (surface roughness must reach Ra≤0.4μm).

• Detect the suction force of the electromagnet (need to ≥90% of the design value, otherwise the electromagnet needs to be replaced).

• Possible reasons: excessive oil viscosity, wear of valve core, insufficient suction of the solenoid.

• How to deal with it:

4. Too much noise

• Check whether the oil suction port of the pump is leaking (the oil suction height is ≤500mm).

• Install a filter at the P port of the valve (filtration accuracy ≤10μm).

• Clean the inside of the valve body and replace the contaminated hydraulic oil.

• Possible causes: cavitation, valve core vibration, oil contamination.

• How to deal with it:

Summarize

The reliable operation of 4WEH16 electro-hydraulic reversing valve must strictly follow the principles of 'installation specifications, fine debugging, strict monitoring, and timely maintenance'. By controlling environmental conditions (temperature, humidity, cleanliness), matching system parameters (pressure, flow, oil), standardizing installation of wiring (direction, fixing, protection), strengthening operation monitoring (pressure, temperature, noise) and regular maintenance (seals, valve cores, solenoids), the failure rate can be significantly reduced (target ≤1%) and extended service life (usually up to 8-10 years), while ensuring efficient and stable operation of the hydraulic system (system efficiency ≥85%). It is recommended to formulate a personalized maintenance plan in combination with the maintenance manual provided by the equipment manufacturer, and train operators to master basic fault diagnosis skills (such as judging the valve body status through pressure gauge and noise) to achieve the full life cycle management of the equipment.