Created on:2021-07-15 14:03

Maintenance of Shearer_ Application of pressure stabilizing and vibration reducing accumulator

Maintenance of Shearer_ Application of pressure stabilizing and vibration reducing accumulator

(1) Raising of the problem

For a long time, the hydraulic system of high-grade common (blasting) mining face often uses many liquid injection guns at the same time, resulting in insufficient liquid supply, and the initial support force of single pillar can not meet the requirements at one time, which causes certain unsafe factors for roof management; Or because the safety valve of the hydraulic pump is not sensitive, the pressure is occasionally too high and the hydraulic oil pipe bursts, which affects the normal production of the working face. In addition, the hydraulic pump can not provide the same pressure of hydraulic oil in time when many liquid injection guns are used. The pressure in the high-pressure steel pipe fluctuates, causing frequent and violent vibration of the high-pressure steel pipe, producing high-frequency noise, making people irritable and affecting the physical and mental health of workers. At the same time, the O-ring of the steel pipe joint is often damaged, resulting in liquid leakage of the system, which wastes materials, It also affects the normal production of the working face and causes great losses to the economic benefits of the coal mine. Therefore, to provide a stable hydraulic system for coal mining face is the requirement of coal mine safety production and improving economic benefits.

(2) Characteristics and application of new type bladder accumulator

Compared with other types of accumulator, the new type of accumulator has the characteristics of oil and gas isolation, sensitive response, small size, light weight, no pollution, no pollution, convenient transportation and easy installation. In the hydraulic system, it can store energy, stabilize pressure, reduce power consumption of hydraulic pump, compensate leakage, absorb impact force and pulsating pressure.

(3) Structure of new type bladder accumulator

The new bladder accumulator is composed of shell, capsule, filling chamber, charging valve, inlet and outlet valve, and its structure is shown in Figure I.

① Generally, the design pressure is 31.5Mpa; The shell diameter is about 0.3m; The volume is about 30L.

② Working principle: the capsule accumulator is composed of a capsule and a shell. The accumulator is divided into two chambers: gas and liquid. The capsule is filled with nitrogen (the precharge pressure must reach 10-12mpa). The chamber composed of the capsule and the shell is filled with hydraulic oil (normal emulsion is generally used). When the hydraulic oil enters the accumulator shell (the pressure of the hydraulic pump is generally 18Mpa), the volume of the gas in the capsule decreases with the increase of the pressure (the pressure in the airbag increases with the decrease of the volume ≠ until it is equal to the pressure of the hydraulic oil), so that the hydraulic oil can be stored. If the pressure of the hydraulic system decreases and the hydraulic oil needs to be increased, the accumulator will discharge the emulsified oil to supplement under the push of the gas expansion pressure in the air bag, so as to stabilize the pressure and make up the leakage. When the pressure of the hydraulic system increases, the high-pressure oil will enter the filling chamber again, so as to always maintain the pressure balance inside and outside the air bag.

③ The accumulator is generally installed above the water tank of the hydraulic pump and connected to the main high-pressure steel pipe through the high-pressure hose, so as to play the role of energy storage, pressure stabilization, pulse absorption, vibration reduction, noise elimination, etc. The connection between the new accumulator and pipeline is shown in Fig. J.

(4) Application effect

① The noise is eliminated and the violent vibration of high pressure steel pipe disappears. In the past, as long as the oil gun was used in the working face, the sound of "Pa, Pa" from the steel pipe vibration hitting the shaping shed would be heard all the time, which would make people upset, unable to carry out normal work and communication, and the workers could not concentrate on their work. Now this annoying phenomenon is gone.

② The O-ring of high pressure steel pipe joint is rarely damaged. In the past, due to the severe vibration of high pressure steel pipe, the O-ring of steel pipe joint was often damaged, and it had to be replaced more than 5 times per shift. Now this phenomenon has disappeared, ensuring the integrity of the system, reducing the loss of energy, greatly improving the utilization rate of working hours, and improving the economic benefits.

③ The energy supply is fast, and the pressure of the hydraulic system is relatively stable. When several oil guns are used in the working face at the same time, the liquid supply of the hydraulic pump can not meet the needs for a moment, the pressure of the main pipe suddenly decreases, the working face can not get high pressure, and the initial support force of the prop can not be guaranteed. At this time, the high-pressure oil in the accumulator will immediately squeeze the high-pressure emulsified oil in the filling chamber to the main high-pressure oil pipe for supplement due to the high-pressure expansion effect in the air bag, so as to supplement the high-pressure energy of the main system and ensure the stability of the whole system pressure (when the liquid supply pressure of the pump station increases, the high-pressure emulsified oil will be automatically added to the filling chamber of the accumulator, Until the pressure is balanced with the main system). Now, even if several oil guns are used at the same time, the pressure input to the working face can ensure that the initial support force of single pillar is about 12MPa.

④ The larger the accumulator volume is, the better the effect of pressure stabilization and vibration reduction is.

(5) Inspection and maintenance

After the accumulator is put into operation, the inflation pressure in the capsule should be checked regularly. If any leakage is found, the gas should be replenished in time. If the leakage is serious, the causes should be found out (capsule damage, lax seal of inflation valve or lax seal of inflation valve seat, etc.) and repaired or replaced in time.

(6) Economic benefits

① Save at least 10 O-rings per day.

② Every time the seal ring is replaced, it takes at least 10 minutes from finding to replacing. If the seal ring is replaced 10 times a day, the time is used for coal production. If the coal production is 50t per day, the annual coal production will be 18000 tons more.

③ The initial support force of single pillar is guaranteed, which is immeasurable economic benefit for roof management and safety management of working face.

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