NXQ-type bladder accumulator as an example to illustrate the accumulator failure phenomena and troubleshooting methods, other types of accumulators can be referred to carry out.

(1) The skin bag type accumulator pressure drop is serious, often need to replenish the skin bag type accumulator, the skin bag of the inflatable valve for the form of a one-way valve, relying on the sealing cone seal (see Figure 5-8).

When the accumulator is subjected to vibration during operation, it is possible for the spool to loosen, so that the sealing cone 1 does not fit tightly, resulting in air leakage. Valve spool taper surface pulled groove, or taper surface with dirt, may lead to air leakage. At this time in the inflatable valve sealing cover 4 into the thick 3mm or so of hard rubber gasket 5, as well as to take the sealing cone grinding to make it close and other measures to solve the problem.

In addition, if the upper end of the spool nut 3 loose, or spring 2 broken or leakage of the case, it is possible to make the capsule nitrogen gas instantaneous discharge.

(2) Short service life of the leather bag

The factors affecting the quality of the bladder, the use of the working medium and the compatibility of the bladder material; or dirt mixing; selection of the nominal capacity of the accumulator is not appropriate (oil flow rate can not be more than 7m/s); the oil temperature is too high or too low; for energy storage, the reciprocating frequency of whether or not more than 1 / 10s, more than the life of the beginning of the decline, if more than 1 / 3s, then the life of a sharp decline; whether the installation is good, piping Whether the design is reasonable. In addition, in order to ensure that the accumulator can work reliably at the minimum working pressure, and to avoid the skin capsule in the process of work often with the accumulator bacteria valve collision, to extend the service life of the skin capsule, po generally should be in the range of 0.75 ~ 0.91 selected; to avoid the contraction and expansion of the skin capsule in the process of work and the amplitude of the impact of the service life of the capsule is too large, to let po>25%p₂, that is, the requirements of the p ₁> 33% p ₂.

(3) Accumulator not working

The main reason for this is that the valve leakage is serious, there is no nitrogen in the bladder, as well as the bladder is broken into the oil. In addition, when p0>p₂, that is, the maximum working pressure is too low, the accumulator completely lost the energy storage function (no energy can be stored).

(4) Poor absorption of pressure pulsations

In order to better play the role of the accumulator on the absorption of pulsating pressure, the accumulator and the main line branch point of the connecting pipeline should be short, the diameter should be appropriately large, and should be installed in a position close to the source of pulsation. Otherwise, it eliminates the pressure pulsation effect is poor, and sometimes even exacerbate the pressure pulsation.

(5) Poor stability of the flow released from the accumulator

The instantaneous flow rate of the accumulator charging and discharging fluid is a variable, especially in large capacity and △p=p₂-p1

The range is large in the system, if you want to get a more constant and larger instantaneous flow rate, the following measures can be used: ① between the accumulator and the actuator to join the flow control;

② Use several smaller capacity accumulators in parallel, instead of a large-capacity accumulators, and several smaller capacity accumulators using different block filling pressure;

③ Minimize the working pressure range △ p, can also be used to appropriately increase the accumulator structure volume (nominal volume) of the method;

④ in a work cycle to arrange a good enough time to fill the liquid, reduce the filling of liquid during the internal leakage of other parts of the system, so that when filling the liquid to ensure that the pressure of the accumulator quickly rise to p ₂, and then release the energy.

Table 5-1 for domestic NXQ-L type skin bladder accumulator allowable charging and discharging flow rate

(6) Phenomenon of oil tank spraying

In practice, sometimes also encountered the phenomenon of oil tank spraying, this is due to the accumulator airbag pressure broken, a large number of bubbles into the oil, so that the compressibility of the oil increased, due to the oil from the high pressure suddenly dropped to low pressure, flow back to the tank of oil in the case of rapid expansion, the pressure in the tank is higher than the atmospheric pressure, so that the oil mixed with the air from the vent together, thus appearing the phenomenon of oil spraying.

Suspected accumulator failure, should first check the accumulator nitrogen pressure.

In addition, if the nitrogen pressure is too high, there will also be anomalies, because the accumulator stored oil is too small to meet the amount of cylinders, can not work properly.