With the extension of the use time of the hydraulic valve in concrete pumps, failures are inevitable. The failure of the hydraulic valve in the pump is mainly referred to too large clearance and hydraulic valve leakage due to wear, gas erosion and other factors. And also refers to the abnormal action or stuck of the hydraulic valve mainly caused by the deposition of hydraulic oil pollutants.

When the hydraulic valve and other components fail, we should ask professionals to repair and replace the damaged parts if necessary to ensure normal operation of the equipment If the filtration accuracy of the hydraulic oil filter is low, or the oil filter is damaged, clean the hydraulic system and replace the clean hydraulic oil and high precision oil filter.

Common Fault of the Hydraulic Valve

Fault of overflow valve
1.System pressure fluctuation
Reason: the hydraulic oil is not clean, the screw is loose, the valve movement is not smooth.
Elimination method: clean the oil tank regularly and tighten the screws.

2. System pressure can not be added at all
Reason: valve core damping hole blocked, poor assembly quality, spring damaged, valve core does not reset.
Elimination method: clean the damping hole and replace the spring.

3. System pressure rise is not high
Reason: Core wear, leakage.
Exclusion method: replace the valve spool.

4. Sudden increase or drop in pressure
Reason: the valve core action is not sensitive, the valve core damping hole is blocked.
Elimination method: clean the valve body and the damping hole.

Varying valve fault
1. The valve spool cannot be moved
cause:
1) The core surface is scratched and the core is blocked.
2) The gap between the internal holes of the valve core and the valve body is improper: the gap is too large, so the valve core is easy to skew, the valve core is stuck; the gap is too small, the valve core is with large resistance, so the valve core can not move.
3) The spring is too soft to push forward the valve core; the spring is too hard to push the valve core in place.
4) The electromagnet is damaged.

Elimination method: return the valve core or replace the valve core; check the clearance; replace the spring.

2. The electromagnetic iron coil is burnt out
Cause: electromagnet damaged; oil viscosity is too large; outer coil exposed, short circuit burned; voltage too high.
Elimination method: replace the electromagnet, filter oil or replace the hydraulic oil; bandage the external coil, replace the electromagnetic coil; adjust the voltage.

3. Exterior leakage
Cause: The sealing ring is damaged; screw loose.
Exclusion method: Replace the sealing ring; tighten the screws.

Hydraulic valve repairment

The significance of hydraulic valve maintenance is not only to save the purchase cost of the components. When the failed hydraulic valve has no spare parts or the order takes a long time, the equipment may temporarily maintain the operation of the equipment through maintenance and the whole production line and its economic benefit is considerable. In the hydraulic valve maintenance practice, the common cleaning processes include:

1)Removing. Although the parts of the hydraulic valve are mostly bolted, the hydraulic valve design is oriented to non-disassembly, If there is no special equipment or professional technology, forced disassembly is likely to cause damage to the hydraulic valve. Therefore, before disassembly, we should master the structure of the hydraulic valve and the connection mode between the parts, and record the position relationship between each part when disassembly.

2)Check and clean-up. Check the dirt deposition of the valve body, valve core and other parts, and remove the concentrated dirt with cotton yarn, hair brush and non-metal scraper without damaging the working surface.

3)Rough washing. Place the valve body, valve core and other parts on the tray of the cleaning box, heat and soak. The compressed air is passed into the bottom of the cleaning tank, and the residual dirt is cleaned away through the stirring of the bubbles. If possible, ultrasonic cleaning can be used.

4)Fine washing. Clean with the cleaning liquid for high-pressure positioning, and finally dry with hot air. Conditional enterprises can use the existing cleaning agent, individual occasions can also use organic cleaning agent such as diesel, gasoline.

5) Assembly. According to the assembly diagram of the hydraulic valve or the assembly relationship recorded during disassembly, be careful not to touch the parts. The original sealing material is easy to damage in disassembly and should be replaced during assembly.

The mixing tank stops rotating under the loading of concrete. If the hydraulic motor and reducer driving the mixing bucket are in good condition, the emergency tubing can be used to unload the concrete. The use method of the emergency tubing is:
First, connect the emergency tubing;
Then, start the engine of the rescue vehicle;
At last, the operating handle of the rescue vehicle is pushed to the "discharge" position to make the vehicle from the concrete.