Valve Rod Research Articles

Research on the operation mechanism and stability of marine textured directional valve

Based on the vibration force analysis of the marine electromagnetic directional valve and Newton’s Second Law, the mathematical model of the displacement of the valve rod under vibration excitation state is established. The influence of vibration parameters and viscous damping coefficient on its operation stability is calculated and analyzed. Results show that the vibration stability can be improved by increasing the clearance viscous damping of the directional valve, and the textured surface affecting on the viscous force and flow resistance characteristics. All of these provide a basis for stability optimization. The on-board experiment of marine electromagnetic directional valve in real-time working condition is operated, the performance difference between the textured and untextured valve is analyzed. The results show that the pressure adjustment time and vibration impact amplitude of two kinds of directional valves decrease with the increase of oil supply pressure, and increase with the increase of navigation speed. The standard deviation of flow fluctuation of untextured directional valve increases with the increase of oil supply pressure, while the flow fluctuation of micro-textured directional valve first decreases and then increases. The unique interface characteristics of the micro-textured directional valve make the pressure adjustment time, the standard deviation of flow pulsation, and the vibration impact amplitude of the micro-textured valve smaller than that of the untextured one.

Development of auto loading device in bearing positioning lip stamping

With the continuous development of our economy, the types and quantity of engine bearing are increasing. In order to prevent the bearing moving in the bearing pedestal, one or both ends of the bearing need to make positioning lip for axial positioning. In order to meet the needs of mass bearing production, an auto loading device for positioning lip of bearing is proposed in this paper. The horizontal conveyor belt and loading guide are used to make the blank turn to the required angle, and then the double cylinder valve and push rod motor are used to realize the time-sharing conveying and continuous loading of the blank. During the loading process, there are inclined slideway and blocking plate to avoid the collision between blanks and ensure the reliable loading bearings. Through the actual production verification, the developed device has the advantages of simple structure, low cost, fine working stability, and made great improving in the efficiency and safety for production of bearing.

Water Flow Control Valve

A water flow control valve is very important tool as per mechanical industry. Present invention in general relates to the field of mechanical engineering and more specifically to water flow control valve, which comprises of Y shape pipe and on/off circle ring. Controlling the water flow is not easy task it is time consuming and simultaneously required more labor which is both slow and exhausting task. Also in simple "Y" shape pipe (two different directions), one cannot control the flow or direction in that shape. Thus there is an urgent need to design and develop am improved system or device for controlling the flow of water. Many attempts are made for the same and few of them are discussed below. CN104373661A discloses power-off protection type water flow control valve. A magnet is fixed to a valve rod, a coil can drive the valve rod, which is driven by the magnet, to move vertically in a reciprocating mode, and a control circuit makes the valve be opened or closed through control over the current direction of the coil. Compared with the prior art, the power-off protection type water flow control valve has the advantages of being capable of effectively lowering the using cost of a user, long in service life, capable of performing water flow protection in case of power-off and providing a manual opening and closing function so that using can be not affected for the user even under the power-off condition, reliable in performance, capable of being assembled or manufactured in an integrated mode and convenient to produce; the opening or closing state can be kept without current, and energy consumption is low.

New Methods to Reset the Secondary Valve Rod of LW6 Breaker Hydraulic Mechanism

New Methods to Reset the Secondary Valve Rod of LW6 Breaker Hydraulic Mechanism

Control measuring and information system of the experimental stand

Modern trends in the development of technology are based on the need for experimental studies of the equipment being developed in laboratory conditions with the maximum approximation of the operating modes to real ones. Such studies are impossible without the development of specialized stands with test automation systems. Automation of processes involves the organization of measuring channels as part of a stand using analog-to-digital conversion (ADC), digital-to-analog conversion (DAC), digital-todigital conversion (DDC) and the development of a hardware-software complex (HSC) based on high-speed computing devices. As part of the project to create new high-tech equipment, the specialists of FSBEI HE “KSPEU” and JSC “ChEAZ” developed and created an experimental stand designed to verify and confirm the correctness of the selected structural and circuit solutions used in the design of a synchronous valve electric motor (SVEM) and rod control station borehole pumping unit (RC SBPU). The object of experimental research was the prototype and prototype electric drives of oil pumping units, as well as their components: SVEM and RC SBPU. The article discusses the ways of organizing the measuring and control channels of the measuring and information system of the experimental bench, which allows to study samples of synchronous valve motors and control stations of the sucker rod pump unit in the regimes that are as close as possible to real field conditions simulating the operation of the oil pumping unit of the sucker rod pump unit. Thus, in the experimental stand, analog, discrete and digital control and control channels are implemented.

A Dynamic Model of Small Modular Reactor Based Nuclear Plant for Power System Studies

Small modular reactors (SMRs), an emerging nuclear power plant technology, are suitable for large grids as well as remote load centers and offer load following and frequency response capabilities. While the SMRs have expectedly higher response rates, detailed dynamic models including reactor dynamics are necessary for power system dynamic studies. This paper presents a dynamic model of an integral pressurized water reactor (iPWR)-type SMR, modeled in Siemens PTI PSS/E, to assess the contribution of the reactor to the power system dynamics. The proposed SMR model mimics the heat generation process and subsequent heat transfer process with the inclusion of the reactor core based on point kinetics, primary coolant based on natural circulation, and a simplified three lump representation of the steam generator. Controllers are designed to operate the turbine valve and reactor control rod in closed loops. The SMR model is integrated with the modified turbine-governor system and a power system study is conducted. Results show the power system and internal reactor responses when subjected to electrical demand variations of 20 ${\%}$ rated electrical output (REO) with a valve rate limit of $\pm \text{80}{\%}$ REO/min.

Analysis of Causes of Valve Rod Fracture of Steam Turbine High Pressure Main Steam Valve

A 300MW sub-critical coal-fired thermal power plant steam turbine generator set # 1 high pressure steam valve stem is fractured. The turbine unit has been running 46000 hours before the crack happened. The chemical component was examined which was in the standard range. they observed the metallographic structure of the broken stem to find the nitriding treatment of fine grain martensite structure at surface area and lath martensite at central section, healthy structure condition. they also found the existing of circumferential oxidized cracks with white corrosion production. According to that, they believe it was caused by residual stress when grinding. Finally, SEM was used to observe the fracture to further confirm our ideas.

Influence of Coolant Pressure Size on Surface Roughness when Stainless Steel Machining

The paper is focused on the influence of the coolant pressure on the surface roughness of the workpiece when machining stainless steels. The components were machined on a STAR SR-32J dual spindle machining center and an external cooling unit HYTEK CHAV 160/150-AF-F-OL was used for cooling. Two stainless steel components were investigated, namely the gas control valve rod and the high-pressure control valve housing, which require low roughness Ra after machining (less than 0.375 and 0.25 micrometers respectively). The first component was tested at 8 different pressures in the range of 150 bar - 10 bar and the second component at 4 different pressures in the range of 120 bar - 10 bar. The roughness parameters were measured by the contact method using the MITUTOYO Surftest SJ-410 Roughness Tester and the Alicona InfiniteFocus optical microscope. Based on these sample input parameters, it was evaluated howmuch the pressure affects the surface quality or suggested its reduction due to the high cost of operation of the external high-pressure equipment.

In-vechicle control method based on null-space for wheel load imbalance of railway vehicle by using pneumatically controllable leveling valve rod

In-vechicle control method based on null-space for wheel load imbalance of railway vehicle by using pneumatically controllable leveling valve rod

Experimental Research of Valve Tightness at Different Closure Forces

Power valves are installed on almost all the pipelines of nuclear power plants performing the functions of regulation and shutting off the flow, so its failure often leads to emergencies. A particularly large number of failures is observed in motor-operated valves. Incorrect setting of the limiting clutch leads either to incomplete closure of the valve or to rod failure. Therefore, the valves are equipment of a nuclear power plant, which often falls into repair shops. Failures leading to an increase of valve leakage are especially dangerous for nuclear power plants. In this case, leakage of high-pressure valves leads to erosion of the sealing surfaces, which only increases the leakage. Thus, it is very important to determine the optimum rotational value when the valve is closed. The lack of conditions for closure force in the standards for valve leakage complicates the issue.
 A bench that allows working in the air with a pressure up to 3.5 MPa was developed on valve rod to study dependence of valve leakage on the rotational moment. Four independent parameters were measured: air pressure in front of the valve under study, closure force of the valve, volume of air loss through the valve and leakage time. A standard stop valve with a nominal diameter of 15 mm and a nominal pressure of 64 atm was used for the study.
 The determined dependence of the leakage on torque value allows recommending a gentler mode of valve closure without significantly reducing its tightness. As a result of experimental data processing, a criterial equation is obtained linking a leakage rate, pressure drop on the valve and a rotational moment value. The received criterial equation will allow defining the compromise between valve closure force and permissible leak level according to regulatory requirements. The analysis of the “leakage/rotational moment” diagram showed the possibility to reveal the damaged valves. This possibility may be used during the incoming inspection of the valves supplied to NPP, which should significantly improve the reliability of their operation.

ANALYSIS OF CAVITATION CHARACTERISTICS IN THROTTLE VALVE WITH DIFFERENT STRUCTURE PARAMETERS

The pressure and cavitation characteristics of fluid through throttle valves with different structure parameters were investigated numerically using computational fluid dynamics. The mass flow rate, pressure drop, and the volume fraction of the vapor in the single and two-step throttle valve were computed. The cavitation regions were mainly distributed on the top of the valve rod and the corner of the valve seat in both of the different throttle valves. The size of cavitation region at the corner of the channel grows firstly, and then decrease with the decreasing opening degree. Furthermore, the lowest pressure region, as well as the area and strength of cavitation region, in the two-step throttle valve were smaller than a single one at the same opening degree. The formula for equivalent orifice area of throttle valve was derived, in order to explain the effect of opening degree. The results indicated that the two-step throttle has high anti-cavitation capability.

BIOFLUID FLOW THROUGH A THROTTLE VALVE: A COMPUTATIONAL FLUID DYNAMICS STUDY OF CAVITATION

Biofluid flow through a throttle valve is investigated numerically and experimentally in our paper. Numerical studies are performed in order to obtain the mass flow rate through the valve under different operating conditions. Pressure drop behind the throttle valve and formation of the vortex flow downstream has been evaluated. The vortices were mainly distributed on top of the valve rod, the corner of the channel and the corner of the valve seat. When valve opening increases, the vortices grow and cause higher pressure drop. In other words, more energy is lost due to these growing vortices and high viscosity of biofluid. Furthermore, experimental flow visualization is conducted to capture cavitation images near the orifice using high-speed camera. The initial position of cavitation occurred near throttle orifice while cavitation zone downstream is caused by circulating bubbles clusters. As the opening of the valve is decreased, the area and strength of vortices in the corner of the channel grow and cause higher pressure drop firstly, then decrease. In addition, there are a lot of bubble clusters on top of the valve rod and the corner of the valve seat, which flowed downstream and collapsed, then filled the entire channel. In general, the valve opening plays very important role in the performance of a throttle valve. The results would help to observe, understand and manage the cavitation phenomenon in a throttle valve, and improve the performance of throttle valves.

Fracture Analysis of Pneumatic Control Valve Rod Used for Nuclear Power Plants

The fracture of a carbon steel pneumatic control valve rod used for Nuclear Power Plants was analyzed in terms of the microstructure, inclusions and fractogragh by means of tensile test, charpy V-Notch impact test, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. The results indicated that the fracture of the rod is induced by the unqualified chemical composition: a large number of inclusions which distribute in grain boundaries reduce the material plasticity and toughness, and eventually cause fracture.

An analytical investigation on the workpiece roundness generation and its perfection strategies in centreless grinding

Continuous improvement of the component roundness accuracy through computer numerical control centreless grinding in high productivity is one of the most important issues particularly for modern automotive and bearings manufacturing. For instance, the process is towards 0.1–0.3 µm roundness accuracy in grinding the engine valve rod because of the increasingly stringent energy efficiency requirement in automotive engines. The characteristics of the computer numerical control centreless grinding process make it challenging, that is, how to assure the workpiece roundness generation in a predictable, producible, highly productive and scientific manner. In this article, a simulation-based industrial feasible approach is presented to model and control the workpiece roundness generation and its perfection strategies in computer numerical control centreless grinding. The kinematics of the workpiece in the process is presented according to the workpiece profile and its geometric configurations. Taking into account the workpiece geometric movements, contact and loss effect and grinding restrictions, a time-domain dynamic model is developed to provide the dynamics description of the workpiece, the grinding wheel and the control wheel in the process. The roundness generation of the workpiece is further predicted using this model. The effects of multiple factors on the workpiece rounding process are discussed and the influences on final roundness errors are investigated.

Research into the Characteristics of Slewing Hydraulic System on Truck Crane

The domestic 25-ton truck crane has the problems of high system pressure during steady slewing and great hydraulic impact when slewing motion starts and brakes. So the simulation model of the slewing hydraulic system and the core hydraulic components was constructed by AMESim. The flow areas of throttling grooves on the valve rod of the directional control valve were calculated by Matlab and converted into text files, which were imported into the simulation model. To get the load parameters of slewing system in different work conditions, an experiment on real truck crane was performed. Then the problem work conditions recurred in the simulation, which showed the veracity of the simulation model. Based on the simulation model an improving method was presented and simulated and the simulation results showed that through the improving method, the system pressure and the hydraulic impact could be efficiently reduced.

Dewatering Unconventional Gas Resources With Sucker-Rod-Pumping Equipment

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 104547, "New Methods and Equipment for Dewatering Unconventional Gas Resources Using Sucker-Rod- Pumping Equipment," by Mark W. Mahoney, SPE, and Randy DeWerff, SPE, Harbison-Fischer, prepared for the 2006 SPE Eastern Regional Meeting, Canton, Ohio, 11–13 October. Dewatering coalbed-methane and low-pressure gas wells is a challenge. Compared to electrical-submersible and progressing-cavity pumps, sucker-rod pumps are very forgiving, and wells can be pumped at very low pump-intake pressure without damaging the pumping equipment. New designs in sucker-rod-pumping equipment and rod-pumping systems for high gas/liquid ratios (GLRs), coal fines, and solids have changed the approach to dewatering unconventional gas resources. Introduction Understanding gas wells and how they affect the sucker-rod pump is needed to apply sucker-rod pumps under mild-, medium-, and high-GLR conditions. Gas lock, gas interference, compression, and decompression often are misunderstood and lead to use of the wrong equipment. Gas Separation Downhole gas separation in front of pump intake can solve gas problems with sucker-rod pumps. The term gas lock often is used to describe any gas problem in a sucker-rod pump. Surface-valve checks and dynamometer-card analysis cannot distinguish between various gas problems. True gas lock exists when the hydrostatic pressure above the traveling-valve ball is greater than the pressure in the pump chamber at the bottom of the downstroke. On the upstroke, the gas expands in the pump chamber but the pressure in the chamber remains greater than the pump-intake pressure; therefore, the standing valve does not open. With true gas lock, the valves stay closed and the same column of fluid is raised and lowered with each cycle, with no fluid being pumped. Compression and decompression must be avoided. A better description of gas lock is "the pump has pumped down to its pump-chamber decompression limit." The ideal-gas law gives the relationship between volume, pressure, and temperature. In simple terms, if the temperature is near constant, then pressure and volume are inversely proportional. On the upstroke, the pump chamber starts with an uncompressible volume according to the design constraints of the traveling and standing valves. As the plunger moves upward, the volume increases and the pressure decreases. When the pump-chamber pressure drops below the pump-intake pressure, the standing valve opens. Pumps contain a certain volume that does not contribute to the pumped volume. This nonpumping volume includes the standing-valve section with the valve ball, ball-guide portion, and the upper-fluid-port portion. Another nonpumping volume is the traveling valve, with its seat, seat retainer, and cage, that functions inside the pump barrel. Pumps are assembled such that the traveling valve does not touch the standing valve when the valve rod bushing is seated in the clutch of the valve rod guide. Space out, when the well is put on pump, can be too far off bot-tom, which increases the nonpumping volume.

Experimental Validation of a Common-Rail Injector Model in the Whole Operation Field

Abstract The present study deals with the definition of an accurate mathematical model of a production common-rail-type injector for automotive diesel engines. The mathematical model defined in a previous work was refined, accounting for a broader range of effects on injector performance, thus allowing a more strict validation of the model predictions against experimental data. The geometry of the control-valve holes, crucial in determining the actual discharge coefficient, was accurately evaluated by means of silicone molds. The moving mechanical components of the injector, such as control valve, needle, and pressure rod were modeled using the mass–spring–damper scheme. The axial deformation under pressure of needle, pressure rod, nozzle and injector body was modeled. This effect was found to also affect the control valve device operation, and was properly accounted for. The model obtained was implemented in Simulink; the ordinary differential equations were solved by means of the numerical differentiation formulas implicit scheme of second-order accuracy, while the partial differential equations were integrated using the finite-difference Lax–Friedrichs method. In order to obtain sufficient data for validating the model in its entire operation field, two separate sets of tests were carried out. In the first analysis, a constant reference pressure was imposed in the rail, and the injector energizing time was progressively increased from values relative to small pilot injections to values characteristic of large main injections. The injected volume per stroke was measured by means of a mean delivery meter (EMI) device. During the second set of tests, the injector was mounted on a flow rate meter (EVI) device so as to measure the injection law. Electric current flowing through the injector solenoid, oil pressure in the common rail, and at the injector inlet, needle, and control valve lift were also gauged and recorded. The good agreement between numerical and experimental results allowed the use of the model to gain greater insight into the mechanisms and phenomena that regulate injector behavior. The nozzle hole discharge coefficient dependence upon time and needle lift was discussed, and the trends were presented in several working conditions. The flow in the control volume holes was studied, in order to determine whether cavitation occurs or not, giving an answer to a long disputed topic. Finally, the effects of injector deformation caused by fuel pressure on performance were investigated.

Failure of a valve rod caused by improper heat treatment and metallurgy

Fractography analysis was used to investigate a structural component which failed during its normal service life. It has been found that imperfections in the metallurgy and heat treatment were the major causes of failure. Some detrimental impurities were found in the material. A number of cracks were initiated at the interface between the impurities and the base material. These cracks were the main reason for the failure. Also several kinds of metallography defects contributing to crack initiation have been found. The metallographic structure of the material is bainite+ferrite; the amount of ferrite increases gradually from the outside to the inside of the part. This was the wrong metallographic structure for this kind of material; it should be sorbite. Cracks initiated and propagated under a relatively low stress level by stress corrosion cracking.

Valve rod for a filter casing with a cover lid

Valve rod for a filter casing with a cover lid

A physical model of high-pressure disruption of bakers' yeast cells

A model is presented for the disruption of microbial cells in a high-pressure homogeniser. It assumes that cell deformation and breakage due to elongational stresses occur in the high-stress zones close to the surfaces of the valve rod and the impact ring of the homogeniser. The equation based on the proposed model predicts an inverse cube-root dependency of the maximum diameter of cells that remain unbroken upon the pressure drop across the valve, and suggests that the maximum whole cell diameter will increase with an increase in the mechanical integrity of the cell walls. Experimental data are provided for the disruption of batch and continuously grown cells of Saccharomyces cerevisiae. The results from these experiments support, and are interpreted in terms of the predictions from, the proposed model.