Papers by Keyword: Relief Valve

Abstract: This paper mainly introduces three types of hydraulic energy-dissipation dampers, which adopts the damping hole, relief valve, and relief throttle valve, and the structures, operation principles and energy dissipation mechanisms in detail. Using AMESim to analyze the performance parameters comparatively, it can be concluded that the hydraulic damper adopting relief valve has strong capability of energy consumption and effectively ensures the safety of engineering structures.

Abstract: After data preprocessing,the autoregressive(AR) bispectrum diagonal slices were figured and fractal box dimensions were calculated. The results show that the box dimensions are different in evidence under different conditions. So the fault pattern recognitions of the relief valve are effective by the method of using fractal box dimension of AR bispectrum diagonal slices, it provides a simple and accurate method for fault diagnosis of the relief valve.

Abstract: Based on the fuzzy method, a PC-based precision force control scheme is proposed for the electro-hydraulic servo press system. The main feature of proposed scheme is to develop a composite control of relief valve and flow servo valve. With the feedback of force sensor, the fuzzy-based control system is realized by LabVIEW for achieving the precision force control of hydraulic cylinder. In the experiments, a practical platform of hydraulic servo press system is used to demonstrate the effectiveness of proposed scheme. The testing results indicate the accurate output responses.

Abstract: Based on mechanical phenomena between two fixed magnetic, when the distance is short, the electromagnetic force are linear,therefore,we can make full use of the characters and make it to be permanent magnetic spring replacing the mechanical spring in hydraulic relief valves. Through the use of the Rare-earth magnetic springs in relief valves, we find it is more sensitive to load. Besides these, the rare-earth magnetic springs have a long life and high temperature resistance without failure by fatigue. So the study and design of permanent magnetic spring type relief valve have large application and research value.

Abstract: Relief valves used in the coal liquefaction equipment are running in an extremely harsh environment with extraordinarily high temperature, high pressure differential, high fluid velocity as well as the intensely slurry flow erosion. The lifetime of relief valves is critically important to the reliability and running cost of the coal liquefaction equipment. Diamond film is potentially used as wear-resistant and protective coating for the relief valve components in coal liquefaction equipment due to its outstanding mechanical and tribological properties. In present study, a layer of high-quality diamond films are deposited on the working surface of conventional WC-Co cemented carbide relief valve components, using the hot filament chemical vapor deposition (HFCVD) technique. Two different types of hot filament arrangements are respectively adopted for depositing diamond films on the interior surface of valve seat and outer surface of valve spool. The fabricated CVD diamond coated relief valve components are characterized using Scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), and Raman spectroscopy. The results exhibit that working surfaces of both valve seat and spool are covered by a layer of continuous, homogeneous diamond films on which well-faceted diamond grains with grain size of ~2-3 μm distribute. Furthermore, the fabricated relief valve components are equipped on a coal liquefaction facility and their performance is evaluated in real production. The results present that the working lifetime is largely elongated up to ~1200 hours, as more than three times as that of conventional tungsten carbide valve components.