Created on:2021-07-24 09:19

Maintenance of mine equipment hoist_ Application of accumulator

Maintenance of mine equipment hoist_ Application of accumulator

(1) Existing problems

Hydraulic station is an important safety and control component of mine hoist, which is used to provide high-pressure control oil for disc brake of hoist. Gkt1.6 is used in a coal mine × The hydraulic station of 1.5-20 type hoist is t414 type. In actual use, there are often faults such as no oil pressure or not reaching the required pressure value. The hydraulic system is very complex, so it is difficult and time-consuming to find the fault, which seriously affects the mine safety and production.

(2) Improvement measures

In order to improve the reliability of hoist braking, the hydraulic system is improved in several aspects.

① In order to improve the reliability of working braking and the performance of pressure regulation, the nozzle flapper type pressure regulator controlled by cross spring is replaced by the electro-hydraulic proportional relief valve. The electro-hydraulic proportional relief valve is composed of proportional electromagnet, pressure pilot valve, main valve and safety valve. The proportional electromagnet generates a force proportional to the input current and acts on the spool of the pressure pilot valve to change the size of its orifice, so as to control the pressure at the inlet of the pressure valve. The device has the advantages of compact structure, stable voltage regulation, good linearity, strong following ability and excellent dynamic performance.

② An accumulator is added in the hydraulic system. After the accumulator is added, part of the pressure oil enters into the A and B oil channels when the system is working. Open the actuator of the hoist, and the hoist can be started; Another part of the pressure oil enters the accumulator through the sequence valve to reserve pressure energy for the safety braking and play the role of oil supplement. Add pressure relay (or electric contact pressure gauge) for residual pressure protection. If the residual pressure of the system exceeds the set pressure value when the hoist stops, the safe braking can be implemented, so as to improve the reliability of working braking.

③ To simplify the hydraulic system, on the basis of meeting the system functions, the hydraulic system and components can be simplified, such as using integrated valve block to connect the hydraulic components to reduce the number of pipelines; The two position two-way solenoid valve with the simplest structure is selected to reduce the probability of component failure; Set the fault monitoring function of the solenoid valve, and use the non-contact sensor to monitor the action of the solenoid valve spool. When the action of the solenoid valve fails, it can implement the safe braking, and provide the alarm signal to display the failed solenoid valve. This not only improves the reliability of components, but also brings great convenience to the maintenance of hydraulic station. The improved hydraulic system is shown in Figure W.

W.jpg

④ The electric control part is controlled by PLC, and the electric control part of the hydraulic system is controlled by PLC instead of the original relay contact control system. At the same time, the programming of PLC is used to set the fault display functions of solenoid valve fault, high residual pressure, high differential pressure of oil filter and high hydraulic oil viscosity, It not only brings convenience to the maintenance of the hydraulic station, but also improves the reliability of the electronic control system.

(3) Effectiveness of improvement

The improved hydraulic system not only greatly improves the reliability of working braking system, safety braking system, components and electric control system, but also greatly improves the overall reliability of the hydraulic system due to the addition of some protection functions and monitoring functions.

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