That when the concrete pump pumping reverse pressure instability or zero suddenly, what should I do? The following a few action take a look at!

The fault phenomenon
1. The reversing pressure suddenly drops to zero;
2. Directional pressure step-down eventually fall to zero;
3. The pressure is not stable, high and low.
4. After reversing pressure does not rise to the set pressure, and stopped at a certain pressure, after the second commutation, pressure continues to decline, sometimes pressure is zero; Or continue to rise, sometimes pressure can reach 19 mpa.

System analysis
Distribution system by a concrete pump accessories constant pressure pump (power element), two concrete pump parts swinging cylinder (actuators), intermediate control valve group (control element), of the rest of the accessories.

The working principle of
Concrete pump parts for the system to provide constant pressure pump pressure oil, to promote concrete pump accessories swinging cylinder movement, the intermediate control valve group control the distribution of oil cylinder action sequence. Because the distribution of S rapidly reversing valve requirements, in S valve commutation instant concrete pump accessories constant pressure pump flow is insufficient, system joined a concrete pump accessories accumulator to complement S valve commutation instant flow. Commutation instant and constant pressure pump displacement, accumulator release energy, system pressure; When reversing after the completion of the action, constant pressure pump accumulator punch, when reach the set pressure value, constant pressure pump variable institutions regulating constant-pressure pump swash plate to zero.

troubleshooting
If you meet the above phenomenon, the first to check the system with and without overflow, see if system can overflow from the following aspects

1. Check the system whether the oil temperature rise, under normal circumstances the overflow components or even the entire system high oil temperature rise;
2. Check whether there is overflow, overflow generally make a sound;
Check pressure gauge pressure, in the case of stop immediately, observe whether the reversing pressure drop is too fast.
More than 3. If there is no phenomenon judgment for concrete pump accessories constant pressure pump problems. Constant pressure pump is variable pump, S output maximum flow when reversing valve, the oil pump of the inclined plate tilt to the maximum level, after the set pressure oil pump output flow approximate to zero, which is oil pump inclined plate back to zero, every reversing concrete pump accessories constant pressure pump will repeat the action, action frequency is closed hydraulic system of concrete pump parts of main oil pump twice, so the concrete pump parts servo mechanism of constant pressure pump, oil distribution disc and pressure cut-off valve parts prone to wear.

Constant pressure pump when reversing swash plate cannot be pushed to the largest position or early pressure cut off, cause pressure instability. You can return to normal after the change