Technologies

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Ebara Engineering Review No.184

Visualization of Pump Internal Flows using Multi-color Oil-film Technique

by Tatsuyoshi KATSUMATA, & Akira GOTO

A multi-color, oil-film flow visualization technique, featuring the use of a tri-primary, color fluorescent powder as a pigment, was proposed and applied for the flow visualization of pump internal flow fields. The flow patterns obtained by the tri-primary and intermediate colors were found to be useful in determining the interaction between various secondary flows, as well as the source of secondary flows. This new technique was used for a diffuser pump (specific speed: 280m3/min, m, min-1) to determine the impeller internal flow at different flow rates, typical flow patterns before and after occurrences of impeller inlet recirculation, and flow separation on the diffuser hub surface. Results obtained assured the adequacy and applicability of this technique.

Keywords
Multi-color oil-film technique, Fluorescent powder, Pump, Inlet recirculation, Flow separation, Reverse flow, Vortex, Secondary flow

Development of a High-Speed Circulating Shallow-Water Channel

by Kazuya HIRATA, Masanori GOTO, & Masanori AOKI

Computational analysis and model tests were done for the development of a circulating water channel. This circulating water channel was designed to have an open channel where it was possible to carry out regatta training. Conventional such channels feature a slow velocity, subcritical flow, and a high water level. The open water channel of the present circulating shallow-water channel features an average velocity equal to rowing speed and a shallow depth. Measures were taken to solve problems such as the occurrence of bubbles at the pump suction and hydraulic jumps due to a supercritical flow being maintained at the open channel.

Keywords
Circulating water channel, Supercritical flow, Subcritical flow, Hydraulic jump, Multi-hole plate, Specific energy, Specific force, Froude number

Servo Control of a Water Hydraulic Axial Piston Motor

by Yoshihiro MOCHIZUKI, & Chishiro YAMASHINA

A study was made on the servo control of a water hydraulic, axial piston, swash plate motor. Tests were done on the speed control and position control, based on the inertial load resulting from driving the motor. Although the friction loss characteristics of the water hydraulic motor were found to slightly differ from those of a conventional oil hydraulic motor, favorable speed control was enabled by the developed servovalve. The precision of the positioning by continuous path control was favorable when the set value was relatively large, but showed deterioration when it was small. This indicated that the dependence of positioning precision on the target value was due to the resistance of the water hydraulic motor at startup, that the positioning precision could be improved by controlling the jerking along the target path.

Keywords
Water hydraulic, Servo control, Servovalve, Axial piston motor, Speed control, Positioning, Environmental impact, Friction

Modern Technology applied for the Development of a Hydraulic Turbine

by Mitsutoshi HAGINO

Since 1992 EBARA is applying 3D viscous flow analysis for the development of hydraulic turbines. Such analysis greatly shortens the development time and cost. The following introduces a case where the development of a hydraulic turbine was done in about 1/4 of the time it takes that by conventional means. Improvement in turbine efficiency and cavitation performance are also discussed.

Keywords
Hydraulic turbines, Hydraulic power plant, Model test, Computational fluid dynamics, Hydraulic performance, Viscous flow, Cavitation performance, Specific speed, Secondary flow, Vapor pressure

Elimination of Viable Particles by UV/Photoelectron Method - Sterilization of Airborne Bacteria -

by Toshiaki FUJII, Masahito AOKI, Shoji YAMAZAKI, & Hidetomo SUZUKI

A new UV/Photoelectron system has been developed for the removal of airborne viable particles in confined space. This system is capable of removing non-viable fine particles as well as viable particles, making it practical as an air cleaning system in mini-environments. Neither filters, ozone, or high-voltage electric fields are used. Bacteria captured and collected by this system undergo sterilization by UV irradiation. This system is ideal for use in pass boxes, food display cases, bioclean rooms and booths.

Keywords
UV/Photoelectron, Ultraviolet rays, Viable particle, Hazard Analysis Critical Control Point, Sterilization, Airborne bacteria, Mini-environment, UV/Photoelectron-unit, Cleanliness, Food display case

Suppression of Water Bloom Growth by a Water Fountain

by Kazuo YAMAGISHI, & Yasushi TAKAHASHI

Tests were conducted to study the effects of a water fountain system on the suppression of water bloom growth. A part of a water reservoir was subdivided into three sections, constituting a test section, a control section, and an out-of-system section. The water quality of each section, segregated by fencing, was analyzed and the data compared. The temperature of the upper water layer in the control section rose and a propagation of water bloom was confirmed. In contrast, there was no significant propagation of water bloom in the test section, due to the effects of water mixing and circulation induced by the fountain. Consequently, it was determined that a water fountain is effective for suppressing the growth of water bloom in a pond or other similar water bodies.

Keywords
Phyto plankton, Aoko water bloom, Water fountain system

A study on the Recovery of Useful Rare Metals from Seawater

by Junichi KANNO, Satoshi KONISHI, & Takashi KAWAKAMI

A study was made on the recovery of useful rare metals such as uranium and vanadium from seawater. Fibrous amidoxime resins, produced by radiation-induced graft polymerization and effective for selective adsorption of rare metals, were used as adsorbents. The study concentrated on large-scale synthesis of fibrous amidoxime resin and the elution of rare metals. Tests were conducted both experimentally using a pilot-scale system and at an actual offshore site. The total uranium recovery in the eluent was found to be about 10.5 g.

Keywords
Radiation-induced graft polymerization, Fibrous amidoxime resin, Monomer-impregnated grafting, Liquid-phase grafting, Adsorbent, Elution, Rare metals, Uranium

Development of Model Predictive Control and Fuzzy Control Systems for Fluidized-bed Incinerators

by Kenichi SUEMATSU, Shunsuke NAKAI, Yoichi KOBAYASHI, & Hisashi OKADA

Two control systems for municipal refuse, fluidized-bed incinerators have been developed as add-ons to the EFOC (EBARA Fluidized-bed Operation Control) system. One is a model predictive control system for stabilizing steam pressure and flow rate at boiler outlets, both of which periodically fluctuate due to refuse input to the hopper. The control is done based on an ARX model of the corresponding plant and existing control system, made using a system identification method. The other is a fuzzy control system for automatically controlling daily amounts of incinerated refuse. Four indexes, relative to the amount of incinerated refuse and exhaust gas concentration, are implemented to constitute a concise inference system. Both control systems have been operated at an actual incineration plant and excellent performance results were obtained.

Keywords
Fluidized-bed incinerator, Waste heat boiler, Model predictive control, Fuzzy control, ARX model

Vibration Analysis on Large-scale Drainage Pumping Station

by Hideaki ANZAI, Tetsuo TAKABE, Shijie GUO, Masato TANO, Hideki KANNO, & Hiroyuki KUBOTA

An FEM model was established for analyzing the vibratory propagation characteristics of large scale pumping stations, whose structures are in the majority of cases made of concrete. Vibration analysis of a station, which was 98 meters in length, 40 meters in width and 34 meters in height, was carried out in a frequency range of 0--100Hz. Analysis results were compared with those of measurements and they showed good agreement. Furthermore, factors affecting the accuracy of analysis were investigated and the results are as the following: (1) Vibration responses at locations nearby the excitation source could be estimated by analyzing neighboring portions of the structure, (2) Spring constants of the ground had influence only on a low frequency range, and (3) Damping ratios were frequency dependent, having great influence on responses at locations away from the excitation source.

Keywords
Vibration analysis, Pump station, Drainage pump station, Finite element method, Vibration accelerator, Vibratory transmission

Diagnostic Software for Estimating the Energy-saving of Pumps equipped with Inverters

by Yoshio MIYAKE, & Katsuji IIJIMA

The use of inverters can enhance pump performance and achieve a saving in energy consumption. This has been proven by the use of a barreled motor pump, Hzfree, in EBARA's Fujisawa Plant Eco-factory Project where an average energy saving under load of 36% is being achieved. However, the energy saving effect by the use of inverters varies depending on site and equipment used. EBARA has developed a software which enables estimation on energy saving of pumps which use inverters. Data obtained by this userfriendly software can be used effectively in proposals to clients, made according to their specific needs and requirements.

Keywords
Energy-saving, Real duty point, Running-cost, Life-cycle-cost, Gain versus investment, Installation near the pumps, Electric power consumption, Circulation pump, Inverter

Fire-fighting Pump Units - Models MDFU & MDFP -

by Susumu SHIMIZU

Two new fire-fighting pump units, models MDFU and MDFP were released into the market. These models were developed in response to Standards on Pressurized Water Supply, Notice No. 8 by the Fire-defense Agency. They feature compactness and high performance, and the technology used is usable for existing fire-fighting pump units. The units comprise 50 L priming tanks, 50 L pressure tanks, and models MDPA and MDP pumps (stainless-steel, multi-stage).

Keywords
Fire fighting pump unit, Priming tank, Pressure tank, Electronic control panel, Multi-stage stainless-steel pump, Flowmeter, Compactness

Wind Turbine Generating System

by Atsushi HIRAYAMA, & Kenji YAMASAKI

EBARA has concluded a domestic distributorship contract with NEG MICON A/S of Denmark to use NEG MICON A/S wind turbine power generators in EBARA's systems. NEG MICON A/S holds the world's top share in wind turbine power generators. At present 17 large-scale systems (225-600 kW per unit) have already been or are in the process of being installed at 8 locations in Japan. Wind turbine power generation is cost effective in that equipment investment cost can be recovered within 10 years, provided a system is installed in a location with an average wind velocity exceeding 6 meters per second. Generated power can be supplied to local facilities and excess power can be sold to electric companies. The following introduces EBARA's wind turbine power generation systems which feature NEG MICON A/S wind turbine power generators.

Keywords
Wind turbine generating system, Wind turbine generator, Clean energy, New energy, Rotor, Blade, Nacelle, Tower

A New Electric De-ionization GDI Unit

by Masaji AKAHORI

EBARA has developed a new electric de-ionization unit, named the GDI (Graft De-Ionization) unit, for producing pure water. Both conventional electrodialysis and radiation-induced graft polymerization are featured in this unit. Product water output from this unit is highly pure (up to 18 MΩ/cm), with low TOC and low silica concentration. This unit is capable of continuous operation, with no need of highly acidic/alkali regeneration agents for ionization or neutralizing agents for wastewater. It is compact and cost-efficient, needing only electrical power to operate. Moreover, it is fully capable of treating highly ionized water.

Keywords
GDI, Electrodialysis, Radiation induced graft polymerization, Ultra pure water, De-ionization

LS16A/WIN-A Data Logging & Distributed Control System

by Hiromasa KAIHATSU, & Kohsuke SUZUKI

EBARA has developed a personal computer DCS, named LS16A/WIN, to be used as a standard system for controlling overall plant operations. Features of this system include the use of a backup personal computer, multiple CPUs, Windows NT, Ethernet, WAN or regular telephone lines, backup power supplies, multi media, among others. This leading edge system is ideal for monitoring and control, as well as for other various computational user needs.

Keywords
Computer, Distributed control system (DCS), Single type model, Dual type model, Windows NT, Ethernet, Wide area network (WAN)

Current Trends in Dioxin Analysis

by Hiroshi OHBA, Sayaka OZAWA, & Tadashi OHBO

Current trends in the dioxin analysis have been studied and compiled. The following includes data on GC/MS measurement, quantitative analysis, sampling, extraction, clean up, and precision control.

Keywords
Dioxins, Measurement, Analysis, Precision control

Engineering Seminar on Fluid Acoustics Lecture 4: Fluid Dynamic Noise of Turbomachinery Systems

by Yoshiyuki MARUTA

This is fourth of a series of lectures for an engineering seminar on fluid acoustics which focuses on control and utilization of noise generated from unsteady flows. This fourth lecture discusses generation mechanisms and control techniques of both tubomachinery noise and self-excited oscillating flow tones. Also discussed are blade passing tones, interference tones between rotor blades and stator blades, as well as between blades and tongue ports, pump pulsation noise, cavitation noise, pipe system noise, and self-flow noise of silencers. Cavity and slit-flow tones are discussed as self-excited oscillating flow tones. It is explained that self-excited oscillating flow tones are induced by both a closed loop which forms between turbulence shedding and sound waves which are generated in a shear flow. It is also explained that acoustic resonance affects the frequency of self-excited osillating.

Keywords
Fluid acoustics, Turbomachinery, Fan, Pump, Piping system, Silencer, Cavity tone, Self-excited osillating tone, Shear flow, Flow induced vibration