Created on:2021-07-24 09:19

Maintenance of mine equipment hoist_ Improvement of hydraulic station

Maintenance of mine equipment hoist_ Improvement of hydraulic station

(1) Introduction

The hydraulic station of mine hoist is an important safety and control component in the hoisting system, which is one of the most critical links to ensure the operation of the hoist. It is combined with hydraulic brake (disc brake) to form a complete braking system, which provides adjustable pressure oil for the disc brake, so that the hoist can obtain different braking torque, meet the safe and normal operation of the hoist, make the hoist work braking or safety braking, and ensure the safety of the hoisting system. However, no matter how advanced the hoist control system is and how perfect the detection means are, in order to make the hoist brake safely and reliably, the hydraulic braking system is the final choice, so the reliability of the hydraulic station is particularly important.

The hydraulic station of an old mine hoist in a mining area is basically a hydraulic station with cross spring electro-hydraulic pressure regulating device. This kind of electro-hydraulic pressure regulating device has large volume, poor reliability, complex control circuit, difficult adjustment, easy drift of operating conditions and poor stability of working pressure. In view of the above problems, according to the actual production, the hydraulic station of the cross spring electro-hydraulic pressure regulating device is improved by using the more advanced electromagnetic proportional valve instead of the cross spring electro-hydraulic pressure regulating device. Through the production and use, the effect is very good.

(2) Problems and improvement of hydraulic station

The hydraulic station of cross spring electro-hydraulic pressure regulating device has been used in domestic hoists for decades. Its control principle is simple, solid and durable. However, from the actual use effect, there are the following problems

① The cross spring electro-hydraulic pressure regulating device is bulky and bulky;

② The connection with the hydraulic station box is complex, and the maintenance and replacement are difficult;

③ Cross spring and KT coil, the key components of voltage regulation, have low assembly accuracy and poor linearity;

④ In the process of adjusting the brake oil pressure, the cross spring is prone to resonance, which makes the brake oil pressure unstable in a certain area and has adverse effects on the speed closed-loop control;

⑤ It is difficult to adjust, the residual pressure of brake oil exceeds the regulation, and the adjustment is cumbersome. It depends on the experience of maintenance personnel, and there is no rule to follow;

⑥ The protection grade of cross spring and KT coil is low, and they are easy to be impacted by external force, resulting in brake oil pressure out of control.

Bymd type electromagnetic proportional valve is used to transform the hydraulic station. The electromagnetic proportional valve converts the given electric signal into proportional electromagnetic force by proportional electromagnet to realize the proportional control of the output hydraulic signal. The change of oil pressure is realized by adjusting the given voltage of the electro-hydraulic proportional valve, so as to achieve the purpose of adjusting the braking torque and ensure the reliability of the hydraulic station.

The hydraulic station has the following characteristics after transformation

① YMD type electromagnetic proportional valve is small in volume, light in weight and easy to install and replace;

② The valve body of the electromagnetic proportional valve is integrated with an overpressure protection unloading valve, which can effectively resist the damage of the pressure oil peak to the electromagnetic proportional valve;

③ The adjustment of electromagnetic proportional valve is simple and convenient, only need to adjust the overflow value of overpressure protection and the maximum working pressure. The oil pressure of the solenoid proportional valve is fixed (0.2 ~ 0.3MPa) and does not need to be adjusted;

④ The installation, maintenance and replacement are convenient. Generally, the electromagnetic proportional valve can be adjusted in advance and packed for standby. Once maintenance and replacement are needed, it can be completed in a short time;

⑤ The electromagnetic proportional valve is an integral valve, which is anti-interference and stable;

⑥ The driving board of the solenoid proportional valve adopts DC power supply and built-in current negative feedback, which can avoid the resistance value change caused by the coil temperature change of the solenoid proportional valve, and then cause the output current change. The control voltage oil pressure characteristic curve is stable with good linearity;

⑦ The electromagnetic proportional valve drive board can be easily connected with the electronic control system.

(3) Summary

After several years of use, the hydraulic station is safe, reliable and stable. The transformation cost is small, only the purchase of electromagnetic proportional valve; The transformation time is short and daily maintenance is used, which does not affect the normal operation of the mine hoisting system. It improves the safety and reliability of the lifting system, provides a strong guarantee for the safe operation of the lifting system, and has promotional significance for the transformation of the hydraulic station which is using the cross spring electro-hydraulic pressure regulating device.

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