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Ebara Engineering Review No.245

Development of a Sliding Bearing Lubricated in Ultra-pure Water

by Kenichi SUGIYAMA

SiC ceramics, which have excellent properties for frictional wear in water lubrication, are used for sliding bearings lubricated in water; however, abnormal wear may occur in ultra-pure water lubrication. In this study, we manufactured specimens with a diamond layer coated on the surface of SiC ceramics by vapor phase synthesis, and evaluated their tribology and erosion corrosion characteristics in water. For the tribology characteristics in tap water and ultra-pure water, no big difference was observed between the SiC ceramics and diamond layer. On the other hand, for the erosion corrosion characteristics in ultra-pure water, the SiC ceramics were significantly eroded while the diamond layer had little erosion, showing its excellent resistance property. Therefore, we conclude that the diamond layer is suitable for sliding bearings lubricated in ultra-pure water.

SiC, Diamond layer, Ultra-pure water, Erosion corrosion, Sliding bearing, Tribology

Energy-saving New Model F3100 Packaged Pump System with Top Runner Motors

by Kazuhiro KANEDA, Yosuke HARADA, & Nobuhiro HIGAKI

The model F3100, a long-selling water-supply package for use in commercial and residential buildings, was remodeled in October 2013. The new product, by adopting top runner motors to meet the efficiency control standard due to be effective from fiscal year 2015, and by running in the newly-developed E-mode operation, has evolved into a model with a higher degree of energy efficiency. The first “Save Energy Pump series” water supply product to hit the market, it also features enhanced ease of operation and installation as well as an improved backup function in the event of equipment failure.

Energy-saving, Top runner motors, Packaged pump system, E-mode operation, Estimated constant end-pressure control, Backup function, Energy efficiency regulations for motors, Inverter, Simple operation, Simple construction

[ARRoWS®] Discharged Aseptic Rinser Recovery System for Beverage Bottling Facility

by Yohei TAKAHASHI, Maina HOSHI, & Masazumi OBA

Aseptic filling systems used at beverage factories discharge a large volume of water used for washing plastic bottles. Chemicals from the disinfectant for bottles need to be eliminated to recover the discharged water. For this purpose, Swing Corporation has developed ARRoWS® discharged aseptic rinser recovery system that applies a combination of a reduction tower in a unique structure, anion exchange tower, and RO flow. Benefits of ARRoWS® include the following.
1) It inhibits the growth of microbes in the recovery equipment.
2) It eliminates the tiny quantities of organic constituents from plastic bottles or disinfectant.
3) It increases the rate of recovery of wastewater.
4) It prevents generation of highly corrosive wastewater.
5) It is space-saving.

Aseptic filling system, Beverage bottling, Bottle rinser, Waste-water recovery, Reduction tower, Anion exchange tower, Rinser waste water, Peracetic acid, Hydrogen peroxide, Sterilized water

Basic Knowledge about Pump Cavitation Phenomenon [Part 1]

by Motohiko NOHMI

This paper presents basic information about the pump cavitation phenomenon. Firstly, the reason why the cavitation occurs is explained using the saturated vapor pressure curve of water. Water vaporizes vigorously when the water pressure drops to the saturated vapor pressure determined by its temperature. This is the principle of cavitation occurrence. In a fluid pipe line, water increases speed at a contraction section, lowering the static pressure at the same time. Then, when the pressure drops to the saturated vapor pressure, cavitation occurs. In the case of pumps, cavitation which occurs at the suction side of a blade because of the pressure drop is typical example. In addition, in transient phenomena, caused by sudden closing of a valve or pump trip, water column separation that is a kind of cavitation occures. One of the problems caused by pump cavitation is pump head drop which makes non-attainment of a desired pressure. In relation to this, suction performance curve, NPSHA, and NPSHR are explained in this paper.

Cavitation, Boiling, Saturated vapor pressure, Suction surface, Water column separation, Net positive suction head (NPSH), Suction performance curve

Water Supply Equipment: Introduction of Product Technologies
− Part 1: Characteristics of Various Water Supply Systems −

by Ryotaro KARAKI

We have since the mid-1970s manufactured and sold water supply equipment (packaged pump systems) to supply water to facilities such as collective housing and office buildings. In this article, we describe characteristics of various water supply systems, including transition of our products. Then, we will follow this up by technical information on water supply equipment to be introduced to you in several articles in a series, providing the installation method of water supply devices, details of different water supply methods, their maintenance and inspection, and the related standards.

Water supply system, Direct connecting system, Reception tank system, Direct water supply system, Direct connecting booster pump system, Elevated water tank system, Direct supply system, Large pressure tank system, Small pressure tank system, Variable frequency control system