Vacuum Valve Research Articles

Remote-Steering Launchers for the ECRH system on the Stellarator W7-X

For electron cyclotron resonance heating of the stellarator W7-X at IPP Greifswald, a 140 GHz/10 MW cw millimeter wave system is in construction. Two out of 12 launchers will employ a remote-steering design. This paper describes the overall design of the two launchers, and design issues like input coupling structures, manufacturing of corrugated waveguides, optimization of the steering range, integration of vacuum windows, mitrebends and vacuum valves into the launchers, as well as tests of prototype parts.

Selection of Appropriate Equipment for Designing Effective Vacuum System

Vacuum systems are designed for a variety of research activities and industrial performs for different vacuum ranges depending upon the process prerequisite. It is very essential that these systems should be designed by selecting the vacuum equipment for proper vacuum generation, precise vacuum measurement and particular vacuum control for immense contribution to the process effectiveness, operational ease, working efficiency and quality product. In this paper effort has been made to clarify the physical concepts to use variety of vacuum pumps, gauges and valves to design different vacuum systems with diverse vacuum ranges for their up to mark effectiveness.

Analysis of the Response of CVD Diamond Detectors for UV and sX-Ray Plasma Diagnostics Installed at JET

Diamond detectors are very promising candidates for plasma diagnostics in a harsh environment. In fact, they have several proprieties which make them suitable for magnetic fusion devices: radiation hardness, high thermal conductivity, high resistivity, high carrier mobility and a large bandgap (5.5eV). The latter makes them insensitive to visible radiation and allows low noise measurements without any cooling. In 2008 two CVD (Chemical Vapour Deposition) single crystal diamond (SCD) detectors were installed at the JET tokamak as extreme UV and soft X-Ray diagnostics [1]. In this work the neutron background in these detectors was measured shielding the UV and soft X-Ray radiation by closing a local vacuum valve. The UV detector was found to be insensitive to the neutron flux, while the soft X Ray detector signal exhibited spikes during the highest neutron rate pulse (neutron rate 1016n/s, which corresponds to a flux of φn ∼105n/cm2s in the detector location). These spikes were found to be due to the (n,p) reaction within the plastic filter in front of the soft X-Ray detector. The UV SCD was also used to perform time of flight (ToF) measurements in laser ablation experiments. ToFs were found to be an order of magnitude higher than expected if only the drift velocity is considered. This discrepancy could be due to a delay between the arrival time of the impurities in the plasma and their emission in an energy range which SCD is sensitive to (Eph >5.5eV). The delay is found to be comparable with the expected ionization times for edge plasma conditions.

A Pipe Heat Insulation Device Featuring Vacuum Valve Box Structure

In order to solve the problem of heat insulation lifetime of low-temperature and vacuum pipes used by cryogenic liquefied natural gas (LNG) filing station, based on the theories of cryovacuum thermal insulation materials at home and abroad, through focusing on exploring such aspects as heat conduction of gas, heat insulating layer design and vacuum degree, Qingdao Luke Auto Gas Development Co., Ltd has developed one new type of pipe heat insulation device. The device is featured by the functions of unloading, pressure regulating and liquid adding, with prolonged life-cycle for vacuum insulation and better operability.

Supervisory control and data acquisition system development for superconducting current feeder system of SST-1

The Current Feeders System (CFS) is essentially an optimized bridge between the power supply at room temperature and Super Conducting Magnet System (SCMS) of the SST- 1 machine at 4.5 K.CFS is a complex electrical and cryogenic network which consists of ten pairs of 10 KA rating helium Vapor cooled Conventional Current Leads (VCCLs), superconducting (SC) current feeder and associated components. For the safe and reliable operation of CFS, it is equipped with different physical process parameters measuring instruments like flow, pressure, temperature, level, vacuum, voltage taps and final control element like control valves, heaters, vacuum pumps etc. PLC program is developed in ladder language for acquiring and controlling the process parameters. Independent SCADA applications developed in Wonderware Intouch software for data communication from PLC, front-end Graphical User Interface (GUI), auto-manual interface, real time trends, history trends, events and alarm pages. Time synchronized communication established between CFS control system and Industrial SQL server (InSQL) Historian for centralized storage of CFS process parameters which intern provides the CFS process data to SST-1 central control room. SCADA based data acquisition and data retrieval system is found to be satisfactory during the recent SST-1 cool down experiment. This paper describes the SCADA and PLC application development and their communication to InSQL server.

Submerged appurtenances and pipelines: An assessment of water levels and contaminant occurrence

Submerged air vacuum valves and pipe leaks are potential entry points of contaminated water into drinking water distribution systems under low‐pressure conditions. Water levels in 20 valve vaults and 17 groundwater wells were monitored weekly for 8 months. The assembled data set indicated that water mains and air vacuum valves were commonly submerged in the investigated system. Urban runoff was found to be the dominant source of flooding in 11 of the 16 vaults containing water. A subset of 14 vaults and 10 piezometers were sampled for microbial and chemical parameters. Concentrations of chemical contaminants generally did not exceed drinking water standards. However, high counts of microbial fecal indicators were detected in numerous vaults. Runoff volumes of up to 255 L/mm of rainfall were found to enter a tested vault, and runoff water was identified as the main source of pesticides, personal care products, microbial fecal indicators, and hydrocarbons in vaults.

Analysis of the wake field effects in the PEP-II storage rings with extremely high currents

We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high-current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves, shielded bellows, BPM buttons and ceramic tiles; vacuum spikes, vacuum instabilities and high detector background; and beam longitudinal and transverse instabilities. We also discuss the methods used to eliminate these effects. Results of this analysis and the PEP-II experience may be very useful in the design of new storage rings and light sources.

Study on Vacuum Control System of Large Laser Facility in ICF

In large and high power laser facility, Vacuum system is an important subsystem of laser facility. It provides reliable, stable and clean vacuum environment for physical experiments. Because of its huge scale, vacuum system stands on a spread and broad district. The vacuum system is composed of some independent subsystems, and every subsystem is composed of PLC control system. So, distribution network control mode is just adopted for the vacuum control system. Each sub PLC system and main PLC system compose large laser facility vacuum control system. Main control system uses monitor computer to control each subsystem and communicates with upper control system through Ethernet. Field equipments drive the vacuum preparation equipments by switch or data format. Through main PLC, field control PLC and equipments obtain, it can gather accurate vacuum gauge pressure data and control all vacuum pumps and valves no mistake.

Preparation and investigation of amorphous silicon thin films and p-i-n structures on their base

A laboratory setup for fabrication of amorphous silicon thin films and structures on their basis by chemical vapor deposition (CVD) has been developed and assembled. All the operating processes were automated by software in LabVIEW media. Special programs and subprograms were created to maintain the corresponding temperature with a necessary accuracy, to control the gas flow controller, as well as to control the vacuum valves. Hydrogenated amorphous silicon thin films of n-, p- and i-types, as well as a test p-i-n structures with different thicknesses were made. Transmission and photoconductivity spectra of the obtained samples were investigated.

Modeling and validation of a boost pressure actuation system, for a series sequentially turbocharged SI engine

An actuation system for flexible control of an advanced turbocharging system is studied. It incorporates a vacuum pump and tank that are connected to pulse width modulation controlled vacuum valves. A methodology for modeling the entire boost pressure actuation system is developed. Emphasis is placed on developing component models that are easily identified from measured data, without the need for expensive measurements.The models have physical interpretations that enable handling of varying surrounding conditions.The component models and integrated system are evaluated on a two stage series sequential turbo system with three actuators having different characteristics.Several applications of the developed system model are presented, including a nonlinear compensator for voltage disturbance rejection where the performance of the compensator is demonstrated on an engine in a test cell. The applicability of the complete system model for control and diagnosis of the vacuum system is also discussed.

Study and Theoretical Calculation on New Type of Adsorption Chiller

One of improving refrigeration performance of adsorption chiller methods is optimizing adsorption chiller structure. A new type of adsorption chiller was proposed in this paper, which obtained two adsorbers, evaporator, condenser and vapor valves between adsorber and evaporator and between adsorber and condenser. The vapor valve was the very important component of the adsorption chiller, which was controlled by pressure difference of both sides of vapor valve. Compared with normal adsorption chiller, the vapor valve replaced the tubes and vacuum valves between adsorber and evaporator and between adsorber and condenser. It can reduce the total equipment size, and decrease the pressure loss of refrigerant flowing in the refrigeration system. Working mechanism of vapor valve and working process of adsorption chiller were investigated, and the theoretical calculation of adsorption chiller was carried out. These works were important foundation for design of adsorption chiller.

K-130 Cyclotron vacuum system

The vacuum system for K-130 cyclotron has been operational since 1977. It consists of two sub-systems, main vacuum system and beam line vacuum system. The main vacuum system is designed to achieve and maintain vacuum of about 1 × 10−6 mbar inside the 23 m3 volume of acceleration chamber comprising the Resonator tank and the Dee tank. The beam line vacuum system is required for transporting the extracted beam with minimum loss. These vacuum systems consist of diffusion pumps backed by mechanical pumps like roots and rotary pumps. The large vacuum pumps and valves of the cyclotron vacuum system were operational for more than twenty five years. In recent times, problems of frequent failures and maintenance were occurring due to aging and lack of appropriate spares. Hence, modernisation of the vacuum systems was taken up in order to ensure a stable high voltage for radio frequency system and the extraction system. This is required for efficient acceleration and transportation of high intensity ion beam. The vacuum systems have been upgraded by replacing several pumps, valves, gauges and freon units. The relay based control system for main vacuum system has also been replaced by PLC based state of the art control system. The upgraded control system enables inclusion of additional operational logics and safety interlocks into the system. The paper presents the details of the vacuum system and describes the modifications carried out for improving the performance and reliability of the vacuum system.

Development of a high vacuum sample preparation system for helium mass spectrometer

A high vacuum sample preparation system for the 3He/4He ratio mass spectrometer (Helix SFT) has been developed to remove all the gaseous constituents excluding helium from the field gases. The sample preparation system comprises of turbo molecular pump, ion pump, zirconium getter, pipettes and vacuum gauges with controller. All these are fitted with cylindrical SS chamber using all metal valves. The field samples are initially treated with activated charcoal trap immersed in liquid nitrogen to cutoff major impurities and moisture present in the sample gas. A sample of 5 ml is collected out of this stage at a pressure of 10−2 mbar. This sample is subsequently purified at a reduced pressure of 10−7 mbar before it is injected into the ion source of the mass spectrometer. The sample pressure was maintained below 10−7 mbar with turbo molecular vacuum pumps and ion pumps. The sample gas passes through several getter elements and a cold finger with the help of manual high vacuum valves before it is fed to the mass spectrometer. Thus the high vacuum sample preparation system introduces completely clean, dry and refined helium sample to the mass spectrometer for best possible analysis of isotopic ratio of helium.

SPME-Adapter : un prélèvement rapide pour l'analyse de traces de COV dans l'air

To simplify grab VOCs sampling in air, the SPME-Adapter was developed. This interface allows combining vacuum sampling in an evacuated vial with SPME pre-concentration. Vials are similar to canisters but cheaper and easier to implement. The vacuum valve of the SPME-Adapter is simply open to let in the air. Then the fiber is introduced to perform in-vial extraction. A 30 min sampling time allows detecting and quantifying μg · m–3 levels with 12 % reproducibility.

The Water Sump Cleaning Machine by Vacuum Suction

This article describes a vacuum water sump cleaning machine which is used to clean up coal mine water sump. Cleaning machine is composed of mechanical structure and electrical control devices. The parts of machine are made up of Walk the flatbed, storage mud tank, vacuum pumps, suction pipe, mud tubes, swing devices, control valves, suction pipe and pressure tracheal. When working, under the function of vacuum pumping, cleaning machine pulls out the vacuum from storage mud tank through the vacuum air feeder. As the vacuum level in the tank is increasing, under the function of atmospheric pressure outside world, the mud flows into the reservoir along the suction tube. When storage mud tank is full, vacuum pump automatically shut down. Turning off the vacuum valve and opening the pressure valve, the slime in the tank under the function of compressed air comes into the mine car through the row mud tube. The layout of this cleaning machine is reasonable, what is more, it is flexible and convenient to operate, so that it reduces the labor intensity significantly and improves the work efficiency of the clearance.

Study of a novel solar adsorption cooling system and a solar absorption cooling system with new CPC collectors

One two-phase thermo-syphon silica gel-water solar adsorption chiller and LiBr-H 2 O absorption chiller with new medium CPC (Compound Parabolic Concentrator) solar collectors were investigated. The reliability of adsorption chiller can be improved, because there is only one vacuum valve in this innovative design. Medium temperature evacuated-tube CPC solar collectors were firstly utilized in the LiBr-H 2 O air conditioning system. The former system was applied in north of China at Latitude 37.45° (Dezhou city, China), the latter system was applied at Latitude 36.65° (Jinan city, China). Experimental results showed that the adsorption chiller can be powered by 55 °C of hot water. The adsorption chiller can provide 15 °C of chilled water from 9:30 to 17:00, the average solar COP (COPs) of the system is 0.16. In the absorption cooling system, the efficiency of the medium temperature evacuated-tube CPC solar collector can reach 0.5 when the hot water temperature is 125 °C. The absorption chiller can provide 15 °C of chilled water from 11:00 to 15:30, and the average solar COPs of absorption system is 0.19. ► Two-phase thermo-syphon adsorption chiller is designed. ► The adsorption chiller can be powered by hot water of 55 °C. ► New CPC solar collectors are used in LiBr-H 2 O absorption cooling system. ► Solar collector efficiency can reach 0.5 when the hot water temperature is 125 °C.

Sensitivity analysis of some critical factors affecting simulated intrusion volumes during a low pressure transient event in a full-scale water distribution system

Intrusion events caused by transient low pressures may result in the contamination of a water distribution system (DS). This work aims at estimating the range of potential intrusion volumes that could result from a real downsurge event caused by a momentary pump shutdown. A model calibrated with transient low pressure recordings was used to simulate total intrusion volumes through leakage orifices and submerged air vacuum valves (AVVs). Four critical factors influencing intrusion volumes were varied: the external head of (untreated) water on leakage orifices, the external head of (untreated) water on submerged air vacuum valves, the leakage rate, and the diameter of AVVs' outlet orifice (represented by a multiplicative factor). Leakage orifices' head and AVVs' orifice head levels were assessed through fieldwork. Two sets of runs were generated as part of two statistically designed experiments. A first set of 81 runs was based on a complete factorial design in which each factor was varied over 3 levels. A second set of 40 runs was based on a latin hypercube design, better suited for experimental runs on a computer model. The simulations were conducted using commercially available transient analysis software. Responses, measured by total intrusion volumes, ranged from 10 to 366 L. A second degree polynomial was used to analyze the total intrusion volumes. Sensitivity analyses of both designs revealed that the relationship between the total intrusion volume and the four contributing factors is not monotonic, with the AVVs' orifice head being the most influential factor. When intrusion through both pathways occurs concurrently, interactions between the intrusion flows through leakage orifices and submerged AVVs influence intrusion volumes. When only intrusion through leakage orifices is considered, the total intrusion volume is more largely influenced by the leakage rate than by the leakage orifices' head. The latter mainly impacts the extent of the area affected by intrusion.

디스플레이공정 진공시스템 밸브응용에 따른 진공특성 전산모사

Abstract Effect of valve conductance on performance of vacuum system was simulated for optimum design of vacuum system. In this investigation, the feasibility of modeling mechanism for VacSimMulti simulator was proposed. Application specific design of vacuum system is required to meet the particular process conditions for various industrial implementations of vacuum equipments. Geometry and length, diameter of vacuum valve were modeled as simulation modeling variables for conductance effects. Series vacuum system was modeled and simulated with varied dimensions and structures of exhaust valves. Variation of valve diameter showed the more significant effects on vacuum characteristics than that of pipeline length variations. It was also observed that the aperture structure of valve had the superior vacuum characteristics among the modeled systems. Key Words : vacuum valve, vacuum characteristics, vacuum system, simulation * 정회원, 인천대학교 신소재공학과접수일자 2012년 3월 20일, 수정완료 2012년 4월 10일게재확정일자 2012년 4월 13일Received: 20 March 2012 / Revised: 10 April 2012 /Accepted: 13 April 2012

The European Supplied Components of the ITER Vacuum Pumping Systems

The ITER Vacuum Pumping systems are designed to pump hydrogen isotopes, including tritium, helium and impurities. The EU is responsible for the in-kind supply of 8 torus-, 2 cryostat-, 3 Heating Neutral Beam-(HNB) and 1 Diagnostic Neutral Beam-(DNB) cryopumps, their 14 Cold Valve Boxes (CVBs) and the cryolines between them as well as the Leak Detection and Localization (LD&L) systems. The design of these systems has progressed well in the past with the exception of LD&L, where the results of a significant R&D program are required to define the design. The torus and cryostat cryopumps incorporate an inlet vacuum valve capable of controlling the pumping speed and require to be sufficiently instrumented for performance and inventory control. In order to fully define the related Procurement Arrangements (PA) and minimize any technological, programmatic or cost risks, a 1:1 Pre-Production cryopump (PPC) has been planned to be built and tested as well as a series of necessary R&D activities will need to be performed. These activities will address all technological challenges, specify the instrumentation needs of these Vacuum Pumping systems and analyze their performance, incorporating also all safety provisions and remote handling requirements.

Optimizing Crankcase Ventilation System of Gasoline Engine

Based on the design goals of the gasoline engine crankcase ventilation system, the features and the layout were described on the gasoline engine crankcase ventilation system, the working model was established on the gasoline engine crankcase ventilation system; using the fluid properties and the mathematical calculation method, the optimizing strategy was proposed on the piston gas leakage, the influencing factors were analyzed on the gasoline engine crankcase vacuum, the design strategy of the flow characteristics was developed on the PCV valve. Using analog control test platform of the gasoline engine, the tests were made on the piston gas leakage, the crankcase vacuum and PCV valve flow characteristics of the gasoline engine crankcase ventilation system. The test result showed that the optimized maximum piston leakage flow was 14L/min; the increasing rates of the optimized intake pipe and crankcase vacuum average were according 5.6% and 8.0%. This could indicate that the working model on the gasoline engine crankcase ventilation system was correct; the proposed strategies on the piston gas leakage, the crankcase vacuum and PCV valve flow characteristics were feasible in the gasoline engine crankcase ventilation system.