Created on:2021-06-30 14:18

Improvement of hydraulic system for maintenance of ceramic pipe extruding machine

Improvement of hydraulic system for maintenance of ceramic pipe extruding machine

(1) Existing problems

The hydraulic system is used to control the main extrusion cylinder, preloading cylinder and barrel lifting hydraulic cylinder of a tubular and rod electrical ceramic pipe extruder. The working pressure of the main extrusion cylinder is 20MPa, which belongs to medium and high pressure; The working pressure of preloading cylinder and barrel lifting hydraulic cylinder is 5MPa and 3.5Mpa respectively, which is low pressure. In the original design, the dual pump oil supply system is used to realize high and low pressure control. The main pump adopts 25SCY14-1B manual variable displacement high-pressure piston pump (rated pressure is 31.5Mpa, flow rate is 25L / min, driving power is 11kw), which provides high-pressure oil for main extrusion cylinder. The low-pressure oil for the preloading cylinder and the barrel lifting hydraulic cylinder is supplied by the low-pressure gear pump. High and low pressure pumps supply oil at the same time. The total power is 13.2kw.

There are two problems in the original design system: one is the poor matching between pump selection and load, and the power consumption is too large; Second, the speed is unstable, which directly affects the product quality.

(2) Improvement measures

The extrusion time of this machine is 5 / 6 and the fast backward time is 1 / 6-1 / 7. The extrusion is of high pressure and low speed, and the required flow rate is only 6L / min. therefore, a small displacement hydraulic pump can replace the original high pressure pump, and an accumulator is set as an auxiliary energy to help push the master cylinder back quickly.

The improved hydraulic system is shown in Figure a. When fast forward, the directional valve 2 is in the right position, and the two pumps are in the same position

When it reaches the extrusion point, pressure relay 4 sends a signal, 3DT is powered on, valve 6 and valve 7 are in the lower position, the main cylinder is extruded by high-pressure small flow pump 1, while low-pressure pump 8 accumulates energy for accumulator 5; When the stop on the piston rod touches the travel switch 9, the reversing valve 2 is in the left position, turns to fast backward, the signal of relay 4 disappears, and the valves 6 and 7 reset. At this time, the two pumps and the accumulator supply oil to the lower chamber of the master cylinder at the same time, realizing the fast backward of the piston; When the piston rod touches the travel switch 10, the reversing valve 2 resets and completes a cycle.

(3) Summary

Here, t6c-003 side plate pin vane pump with flow rate of 6.4l/min is selected for main pump 1, and nxq-10 bladder accumulator is used for accumulator, so that the driving power of main pump is reduced from 11kw to 3KW. Because the vane pump is used, the flow pulsation is greatly reduced, the smoothness of extrusion speed is improved, and the quality of ceramic parts is improved.

In this case, the accumulator is used as auxiliary energy to meet the needs of short-term and large flow of the system, so as to reduce the displacement and driving power of the hydraulic pump and achieve the purpose of energy saving. The method is worthy of reference in similar occasions.

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