Research On Key Technology Of Self Protective Ultra High Pressure Vessel With Tooth-Locked Quick-Actuating Closure Used In Seafood Processing

Ultra High Pressure (UHP) technology is widely applied in various modern industrial fields, such as petrochemical industry, isopressing and liquid jet, etc. The use of UHP for seafood processing, which has been developed extensively, potentionly addresses requirements of modern consumers who prefer minimally processed seafoods. One advantage of UHP technology is that it does not use heat, which causes the sensory and nutritional attributes of seafood products remain virtually unaffected. By this way, quality of seafood products is improved compared to those processed with traditional thermal methods. This technology has a promising future.Ultra High Pressure Vessel (UHPV) is one of core equipments of UHP technology. UHPV employed in seafood process particularly specializes in quick-actuating end closure, ultra high working pressure and long fatigue life, and its safety is of great importance. Financed jointly by Fundamental Project of Zhejiang Science & Technology Bureau, the Excellent Talent of New Century of Education Ministry and the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20010335032), a series of research has been carried out on some key technologies of UHPV:(1) UHPV Structure with self-shielding and quick-actuating device. Based on some advantages of flat steel ribbon-wound pressure vessel and requirements of essential safety and quick-actuating on UHPV, a novel structure of UHPV was put forward, which can shield vessel with protective Flat Steel Ribbons (FSR) and achieve quick-actuating with meshing gear. A new type of Tooth-Locked Quick-Actuating (TLQA) end closure was also put forth, in which detachable seal plug and end head were employed.(2) Shielding capability of helically winding FSR layer. Based on energy deposited in UHPV, the formula of ultimate load-bearing capability as well as energyabsorbed before fracture of FSR were derived. The shielding function and capability of FSR to vessel was analyzed quantificationally in detail, and 2 design criterions on FSR were put forward.(3) Design criterion on Prestressed Collar (PC). The force state and protective function of PC were analyzed in detail, and a method was given to determine some key parameters on prestressed collar, and a design criterion on PC was also achived.(4) Mechanical analysis on sealing process of delta-ring. According to force state features of delta-ring, two simplified mechanical model, that is, rectangular ring model and line model, were proposed. Based on elastic-plastic theory and principle of sealing process of delta-ring, the contact pressure between delta-ring and vessel shell, as well as the stress and the strain of delta-ring are analyzed, and the formulation of the residual contact pressure vs. the working pressure, the material properties and geometric parameters were obtained. The formulation can be applied to the delta back-up ring, but also to the carriers of in dual "O" ring seal.(5) Numerical simulation on strength of UHPV and structural optimization on its key components. A 3-D FE whole model was established to simulate peak stress in TLQA end closure of UHPV, and a 2-D FE whole axisymmetric model was also established to simulate buttress thread end closure. Optimized structures of this two kind end closure of UHPV were achieved, and fatigue life of vessel was extended.(6) Experiment on the self-shielding and quick-actuating UHPV. An experiment was carried out to investigate the strengths of seafood UHPV, and the sealing properties and quick-actuating efficiency were verified. Burst experimental results of 6 model vessels proved that the derived formulations on ultimate load-bearing capability and energy absorption of FSR layer are reasonable.