共查询到20条相似文献，搜索用时 15 毫秒
1.
张庭祥 《山西广播电视大学学报》2013,(2):57-60
压力控制阀是液压系统中重要的 控制元件,作为压力控制阀的三种主要元件：溢流阀、减压阀、顺序阀,从其正作原理、性能结构、外形差异、不同的功能以及在工程实际中的选择和调节等方面分析归纳。对三种压力阀的异同之处进行研究辨析。为学生学习本课程和以后在实际工作中提供重要的参考依据。 相似文献
2.
In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied increasingly in the water network, and in order to reflect the network operational condition more accurately, a new water network macroscopic model is developed by taking the auto-control adjusting valve opening state into consideration. Then for highly correlated or collinear independent variables in the model, the partial least squares （PLS） regression method provides a model solution which can distinguish between the system information and the noisy data. Finally. a hypothetical water network is introduced for validating the model. The simulation results show that the relative error is less than 5.2%. indicating that the model is efficient and feasible, and has better generalization performance. 相似文献
3.
INTRODUCTIONTheinternalcombustionengineisthemostwidelyusedpowermachineryinmodernsociety ,butisalsooneofthebiggestenvironmentalpol lutantsources.Tomeetmoreandmorestringentemissionrequirements,manyadvancedtech niques,suchastheleanburntechnique ,multi valvet… 相似文献
4.
为提高重介质管路平板闸阀的使用寿命,针对重介质管路的特点,改进了平板闸阀的结构,并利用ANSYS有限元分析软件,建立了阀体和闸板的流体动力学分析和结构应力分析三维模型,数值模拟分析它们的受力状况及边界条件,并对结构改进前后的受力进行了对比分析,验证了设计的可靠性。 相似文献
5.
溢流阀、减压阀和顺序阀在许多方面很相似,容易混淆。本文从工作原理,压力判定和用途等方面作一些阐述,力求使三者之间更易区别。 相似文献
6.
周晓波 《洛阳工业高等专科学校学报》2011,21(2)
利用一种新型的智能电液阀门驱动装置、工业控制计算机,结合CAN总线技术,从软、硬件两方面设计了船舶阀门遥控系统,实现了对船上各个阀门的远程控制及对其状态的实时显示。该方案的实现可以提高船舶机舱自动化水平。 相似文献
7.
压力报警传感器校验后的设计 总被引：2，自引：0，他引：2
压力报警传感校验台利用气压系统来实现零件的装卸,压力的校验和报警以及模拟汽车行驶时的振动。为了达到准确控制系统压力值的目的,校验部分的手动阀为自制阀;为了保护精密压力表,系统采用了改装减压阀。 相似文献
8.
9.
单向阀结构简单，性能稳定，被广泛地用于液压系统中，起着其他控制阀不可替代的作用。单向阀还可与其他控制阀组成复合阀，也被广泛地用于液压系统中。 相似文献
10.
The poppet valve is a fundamental component in fluid power systems. Under particular conditions, annoying “squeal” noises may be generated in hydraulic poppet valves. In the present study, the frequency spectrum of the squeal noise is obtained by analyzing the sampling data from the accelerometer mounted on the valve body. It is found that the flow velocity, pressure, and structural parameters have crucial effects on the properties of squeal noise, especially frequency. Larger valve chamber volume or lower backpressure leads to lower fundamental frequency of the squeal noise. An explanation for the squeal noise, as a result of Helmholtz resonance, is suggested and proved by experimental results. 相似文献
11.
吴百中 《温州职业技术学院学报》2011,11(2):56-59
氟塑料衬里阀门是国内广泛应用的耐腐阀门,但其衬里采用的是模压烧结成型工艺,存在较多缺陷。阀门防腐衬里采用注塑成型工艺可解决这一问题。该工艺可大大缩短成型加工周期,降低能耗,减轻劳动强度,提高成品率和防腐性能。 相似文献
12.
分析了液压阀汽蚀产生的原因以及给液压阀带来的影响;给出了防止汽蚀破坏液压阀的方法,以延长液压阀的使用寿命,保证液压阀的可靠性. 相似文献
13.
Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system 总被引：2，自引：0，他引：2
Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using
advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The
working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model.
Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as
poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was
conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera.
The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good
agreement with the numerical result.
Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for
Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097) 相似文献
14.
网络化课程为教育走向社会、走向生活提供了有力的支持和保障,使教育的社会化功能进一步凸显,同时也使学习者的学习呈现生活化、个性化,因此探究网络平台下课程建设具有非常重要的意义,拟对网络平台下高校经济类课程建设进行探究。 相似文献
15.
The weighing system designed for large structure object is mainly composed of three parts. The part of hydraulic system is made up of hydraulic cylinders, high pressure hydraulic hoses and electric pumps; the part of computer controlling system comprises pressure sensors, displacement sensors, data acquisitions, RS 485 network and the computer controlling model; the part of loading system is composed of the fulcrum structure and the concrete girder. The measurement principle and composition of the weighing system are discussed in this paper. Credibility and security of the weighing system are fully considered during the design phase. The hydraulic system is controlled by pilot operated check valves in case of the sudden loss of system pressure. The states of all gauges and RS485 network are monitored by computer controlling system functioning in different modules. When the system is running incorrectly, it will be switched to manual mode and give alarm. The finite element method is employed to analyze fulcrum structure so that the system has enough intensity to be lifted. Hence the reliability of the whole system is enhanced. 相似文献
16.
The power of hydraulic piston engines is much affected by the on-off valves which control the fuel injection of the piston assembly. Therefore, the opening time of the seat valve used as the on-off valve is optimized by minimizing the axial flow forces on the spool. A damping sleeve with orifices is proposed to change the valve internal geometry. Experimental and numerical investigations of the flow forces acting on the spool with and without the proposed damping sleeve are carried out to identify the differences in the flow field and to minimize the forces’ effect. The simulated results fit the experimental results well. Both results show that the proposed damping sleeve affects the pressure distribution along the spool cone surface and the jet stream direction significantly. The effects of the orifice’s width, height, and relative sleeve installation positions on the flow field and cavitation are assessed using simulation methods. As a result of the flow field changing, the damping sleeve can reduce the flow forces significantly and even reverse the forces’ direction at the cost of a little flow loss. The opening time of the seat valve can be reduced by 31% to 0.67 ms by using the proposed damping sleeve. 相似文献
17.
With the analysis on regulating system in 200 MW steam turbine, the necessity of appending the fast-opening function to the original system is set forth and a new type of fast-opening mechanism is devised. The mathematical model of system is built up. With the use of AMESIM software, the displacement curve of the piston, the force curve of the cartridge valve spool, the pressure curve and the flux curve in the regulation process are obtained based on simulation. The performances of three fast-opening systems composed of cartridge valves with different diameters are compared. Based on the analysis on factors that affect the execution time of fast-opening, the dead zone of the fast-opening system is put forward. To overcome the defect, different operation modes are adopted for different zones. The result shows that with the increase of the valve diameter, the regulating time in the dead zone significantly exceeds the fast-opening time in the whole journey. Accordingly, the optimization operation tactic in the dead zone and the qualification conditions are brought forward. The fast-opening system composed of 32 mm cartridge valves is taken as an example with use of the tactic. The simulation result shows that the maximum regulating time is shortened by 509 ms. 相似文献
18.
This paper has introduced the developments of water hydraulic axial piston equipments.According to the effects of physicochemical properties of water on water hydraulic components,a novel valve plate for water hydraulic axial motor has been put forward,whose moment exerted by the fluid field between valve plate and bearing plate is balanced entirely.The material screening experiment of valve plate is done on the test rig.Through numerical simulation the effects of some geometry parameters on the performance of water hydraulic motor have been studied.The silencing grooves on the valve plate in water hydraulic motor can reduce the pressure shock and the occurrence of cavitation effectively.It is evident that the appropriate structure should change the wear status between matching paris and reduces the wear and specific pressure of the matching pairs.The specimen with the new type valve plate is used in a tool system. 相似文献
19.
《天津大学学报(英文版)》2017,(5)
Based on information entropy theory, the definition of relative entropy, and the relative entropy minimum principle, this study establishes a multi-objective optimization model for a key valve opening of an urban water distribution network(WDN). Each node pressure is taken as the main research object to reduce pipeline leakage. Moreover, genetic algorithm is applied in the proposed model to solve the key valve opening of the actual WDN in a city in southern China. Using the proposed model, the relevant decision variables of a WDN can be optimized to provide a new manner of network dispatching. 相似文献
20.
李鹏清 《石家庄职业技术学院学报》2013,(6):16-18
正确选用阀门是保证管道系统正常运行的必要条件.介绍了在管道工程安装中阀门选用的步骤.从阀门的构成部件、边界范围、压力-温度等级、口径、尺寸、连接形式、主要材质、开度指示及锁紧装置、检验试验、运输包装及标识等方面,对阀门选用的技术条件进行了说明. 相似文献