Multistage pressure cylinder and pressurization usage method and depressurization usage method thereof

Abstract

The invention relates to a multistage pressure cylinder. According to the multistage pressure cylinder, an ordinary pressure cylinder cavity B is divided into a cavity body B and a cavity body C through adding of a back rod of a piston and a secondary pressure cylinder, multiple pressure ratios which are convertible are provided, one of the cavity body B and the cavity body C, which is provided with the larger effective area, serves as a cavity body D, and the other one of the cavity body B and the cavity body C, which is provided with the smaller effective area, serves as a cavity body E. The pressurization process comprises two steps, firstly, pressure oil is input into the cavity body D, and a cavity body A outputs hydraulic oil with the pressure ratio to be D / A (an area ratio); and then the pressure oil is input into the cavity body D and the cavity body E simultaneously, and the cavity body A outputs the hydraulic oil with the pressure ratio to be (D+E) / A (an area ratio) to complete the pressurization process. During depressurization, firstly, a main hydraulic cylinder is communicated with the cavity body A of the multistage pressure cylinder, the cavity body D is communicated with an energy accumulator group, a liquid is charged into the energy accumulator group after the depressurization with the pressure reducing ratio of A / D (an area ratio) is achieved, and then the depressurization is conducted step by step. The multistage pressure cylinder is used in a hydraulic system of a hydraulic machine to achieve graded pressurization during pressurization, graded energy recovery is achieved stably through conversion of pressure ratios during depressurization, and hydraulic shocks are reduced.

Description

technical field [0001] The invention relates to a hydraulic booster cylinder, in particular to a multi-stage booster cylinder and its pressurization and pressure release methods. Background technique [0002] In order to improve the efficiency of pressing and reduce the pressure level of hydraulic system pipelines and valves during the pressing process of hydraulic presses, booster cylinders are usually used, such as figure 1 The typical structure of the booster cylinder is composed of front cylinder head 1, piston 2, cylinder barrel 3 and rear cylinder head 4. 3. The rear cylinder head 4 forms a rodless chamber B. The effective area of ​​cavity A is smaller than that of cavity B, and the effective area ratio is usually about 1:2.0-2.5. During pressurization, under the control of the hydraulic system, the system pressure oil is input into chamber B, and the hydraulic oil in chamber A boosted by the effective area ratio is output to the main hydraulic cylinder of the hydrau...

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Problems solved by technology

[0003] The system pressure oil of the hydraulic press is generally 15-17MPa, and the maximum pressure can reach 30-35MPa after boosting. Since the main hydraulic cylinder of the hydraulic press has a large volume, the pressurization of the main hydraulic cylinder from the system pressure to the boost pressure is a gradual increase in pressure. In the initial stage of supercharging, the pressure difference between the pressure of the main hydraulic cylinder and the working pressure of the supercharging cylinder is close to 20MPa. Can be converted into heat or noise, wasting energy

[0004] After the pressing is completed, the main hydraulic cylinder stores a considerable amount of hydraulic energy. The general method of pressure relief and recovery of pressure energy is to directly release the high-pressure oil in the upper chamber of the main hydraulic cylinder to the accumulator group. However, due to the large pressure difference, there is Hydraulic shock, have to use accumulators with high pressure resistance, and the energy recovery rate is low

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