Designing And Optimizing Of The Oil-water Balance System Of 3500 Ton Hydrostatic Testing Machine

At present,China is the second largest energy producer and consumer in the world. But the structure of energy is not reasonable and coal consumption share is too large.During the 12th Five Year Plan Period,the state has formulated an important policy that the consumption of petroleum and natural gas is able to be gradually increased in the primary energy consumption in future, At the same time,it also contributes to the rapid development of many other industries, including welded pipe.API standards and national standards stipulate:each pipe must be carried out hydrostatic test and also needs to keep the pressure for a certain period of time. Its purpose is to test whether the steel pipe is qualified and to eliminate the residual stress of steel tube in the welding process.Residual stress easily leads to fatigue defects or stress corrosion in steel pipe, simultaneously to accelerate the expansion of cold cracking, to reduce the low temperature toughness of material, so the water pressure test is very necessary.This paper takes the oil-water balance system of a set of 3500 ton hydraulic press as the research object, first to find the point and reason of instability of axial sealing hydraulic pressure testing by mechanica calculations,we can determine steel pipe hydraulic pressure testing the minimum pressure difference is 0.23MPa according to the provisions of the minimum standard steel pipe,force center allows offset is 20mm,and propose design idea of system by mechanical model.Hydrostatic testing is necessary step of steel pipe production finish line,the work state is determined by the host of production speed,according to the pre precision welding unit’s speed of 10m/min,the time required for the production of each pipe is 7.5min,so we can determine the total time limit is 60s in oil-water-balance system according to this time.then design system according to the time distribution of each working procedure.For a long process of filling water and testing,we need to shorten the working hours without affecting the stability of test curve.The working pressure of system is 12-15MPa.we take full account of reliability of the system and exchange of components in the type selection design.After most designs have been completed,we can see that the hydraulic pressure testing machine can meet the requirements of the pressure time control in 60s according the producting of several types pipe,and this testing machine could test pressure steady and fast for several types pipe.The test curve of this hydrostatic testing machine is more stable,this machine is more stable than old hydrostatic testing system.