Analysis Of Releasing Law For High Pressure Chamber And Design Of Rapid Non-impact Pressure Relief Valve

After the pressing stroke accomplish and before the cylinder return, a great hydraulic energy is accumulated in the cylinder and part of the system pipelines due to the oil compressibility for large tonnage and high-speed hydraulic press, which has large cylinder and high working pressure. Besides, a part of energy which is caused by the deformation of the press is stored. These energy should be released by some kind of reasonable way, or else tremendous hydraulic shock and violent frame vibration will take place. It threatens to the safety of workers and does harm to the device. At present, the research of releasing law for high pressure chamber is not enough, it lacks of convincing theory evidence to guide the pressure releasing process. This directly results in that the impact and vibration phenomenon during the pressure releasing process can’t be solved radically. In order to release pressure rapidly under the smooth precondition, it is imperative to study the releasing law thoroughly for high pressure chamber.Impact is the response of system to the momentum change. The primary cause of impact and vibration during the pressure release process of high pressure chamber is unsuitable controlling of the momentum and its variable quantity of the discharged oil. If the oil in the high pressure chamber is discharged with its fastest speed all the time under the condition of less impact and less vibration, the smoothness and rapidity will get a better unification during the pressure release process. Therefore, a pressure relief method was proposed with which the high pressure hydraulic fluid was discharged with maximum momentum variable quantity in less impact, less vibration and non-cavitation. Based on the model of variable orifice, by theoretical analysis and formula derivation, it came to the conclusion that the product of throttle area of pressure relief valve and pressure of chamber is a constant value at any time during the pressure release process. The relationships among the pressure of chamber, the throttle area of pressure relief valve, the oil flow rate of pressure relief valve, the pressure relief time were obtained. We have a further recognition to the releasing law of high pressure chamber.Based on the further study of the releasing law for high pressure and the load-sensing theory, the thought about a new rapid non-impact pressure relief valve was proposed. The concrete structure and working principle of the valve were designed and explained, especially the main valve core. The valve could automatically change the throttle area of variable orifice according to the pressure of chamber. Oil in the high pressure chamber is discharged with its fastest speed at all time under the condition of less impact and less vibration. It basically meets the requirement of smoothness and rapidity during the process.The test scheme of new rapid non-impact pressure relief valve was designed in this paper. Collect relative dates, analyze and process them, compare with the results which were gotten by previous theoretical analysis, it could prove the feasibility and advancement of this pressure relief method, meanwhile, it could provide theoretical basis for the further optimization and improvement of the valve detailed structure and function.