2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 201525aD-1
September 25th (Fri.), <10:00-12:00>
Room 2Development of the Static Measuring Equipment underVacuum Environments.
〇Tomoko NAKAYAMA, Teppei HOTOHARA, Tomofumi MOGAMI, Yoshiya
MIYABAYASHI and Nobuo NOMURAKASUGA DENKI, INC

Abstract:
Chemical compositions of the ions generated by atmospheric pressure
helium plasma were investigated using an atmospheric pressure ionization mass
spectrometry (API-MS).
The plasma generator used in this experiment was composed by aunion-tee, a quartz glass tube and a stainless steel rod. In the negative ion massspectrum with a distance between the glass tube tip and the sampling orificebeing 5 mm, several ion species were observed. The observed ions include O－,
OH－, O2－, O3－, CO3－, HCO3－ andHCO4－. Most of these ions formed hydrated cluster ions and the ions ofO2－(H2O)n were the most abundant in the spectrum. The spectrum changed
significantly by changing the distance between the glass tube tip and thesampling orifice to 10 mm. The peak of CO3－ became the most intense peak
and the ions of O2－and HCO4－ decline, which was probably due to theion-molecule reactions with surrounding molecules.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

25aD-2September 25th (Fri.), <10:00-12:00>
Room 2

Charge neutralisation from the side surface of an insulatingplate -- Use of grounded planes to control ion flows
A. OhsawaJNIOSH

Abstract:
This paper presents the effect of the placement of grounded planes tocontrol ion flows on charge neutralisation from the side surface of an insulatingplate. We investigated the phenomena of this charge neutralisation using 2-D
electrohydrodynamic simulations with an insulating plate with 1 cm or 1 mm thick
and with different initial charge distributions at 1 µC/m^2. Consequently, we
found that the grounded planes can modify the charge neutralisation; however, it
is not easy to neutralise the surface charges uniformly, so that charge
neutralisation from the side surface of an insulating plate is improper for practicalapplications; as concluded previously, we can suggest again that simultaneous
charge neutralisation from both larger surfaces would be proper.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

25aD-3September 25th (Fri.), <10:00-12:00>
Room 2

Minimisation of offset voltage for pulse-DC corona ionisers
A. OhsawaJNIOSH

Abstract:
We present an experimental demonstration of a prospective idea
obtained from 2-D electrohydrodynamic simulations of positive and negativeions where continuously emission of quasi-neutralised positive and negativeions from corona ionisers can yield zero offset voltage. We developed acontinuous balanced pulse-DC ioniser using FET push-pull circuits anddemonstrated this theory.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

25aD-4September 25th (Fri.), <10:00-12:00>
Room 2

Discharge Current from two-terminal devices measured by
the discharge-current probe
Yutaka Soda
Probetek

Abstract:
Contact discharge from two-terminal devices was investigated using thedischarge-current probe, which was newly developed current-probe formeasuring the contact discharge. A contact-pin and a discharge-resistance canbe connected by SMA-connector. A single stripe applied 20V on a bakelite-stage
discharged with 60mA peak-current, whereas that on a metal-stage increased to100mA. The capacitance estimated by integrating the current-waveform
increased with the material of the stage rather than the size of the pattern. Twoterminal devices of a resistance, an inductance and a capacitance weremeasured the discharge-current. The peak-values were almost equivalent,however the decay-waveforms were different as the current delayed across theelement.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

25aD-5September 25th (Fri.), <10:00-12:00>
Room 2

Investigation of a Fire that Occurred while Transferring
Gasoline from a Drum to a Tank of a Fixed Oiling Equipment
Hiroyuki TAMURA
National Research Institute of Fire and Disaster

Abstract:
At a fixed oiling equipment in a plant, ignition happened whiletransferring gasoline from a drum to a tank of a fixed oiling equipment, andworker's protective wear was damaged by a fire. The possibility of the ignition bystatic discharge was examined as a fire cause. Because antistatic measures
were not taken, it seemed that the worker was electrified. The induction charging
happened in an aspirator pipe when the electrified worker gripped the aspirator
pipe. It has been understood that the electrical discharge by the electrification
has energy that exceeds the minimum ignition energy of gasoline.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

25aD-6
September 25th (Fri.), <10:00-12:00>
Room 2

Electric Field Strength at the Surface of a GroundedElectrode by a Charged Particle Cloud Simulated by Linecharges and Condition for Discharge Inception〇Yoshio HIGASHIYAMA, Masaaki ENDO and Toshiyuki SUGIMOTO
Graduate School of Science and Engineering, Yamagata UniversityAbstract:
To cause a large scale electrical discharge from a space charge cloud, acharged particle cloud was formed by ejecting from a corona charger consistingof a wire to cylinder electrode. The potential distribution around the cloud andthe electric field strength for streamer discharge inception from a grounded
sphere electrode was investigated by field calculation using a charge simulation
method. Based on the experimental data, a model of charged particle cloud wasconstructed. The space charge of the cloud was simulated by line charge with acharge density of around 8uC/m estimated from a discharge current. The
potential in the center of the cloud reached at 350kV/m for a 4 m long and 1 m
diameter cloud. Although the electric field strength at the surface of a sphericalelectrode with a smaller diameter becomes higher for the same charged cloud,under the condition when a brush discharge was observed, the electric fieldstrength was almost the same value regardless of diameter and location of asphere electrode. Furthermore, the ionization disatnce obtained by calculation
was consistent with a length of a streamer discharge extending from a groundedelectrode.

2015 Annual Meeting of The Institute of Electrostatics JapanTokyo Metropolitan University
September 24-25, 2015

25aD-7
September 25th (Fri.), <10:00-12:00>
Room 2

Dust-proof performance of bi-polar electrostatic ionizer
Naoto Nogera1,Teruo Suzuki1,Kwangseok Choi2,Mizuki Yamaguma2
Kasuga Denki Inc.1,National Institute of Occupational Safety and Health,Japan2

Abstract:
In this paper, we investigated the dust-proof performance of the bi-polarelectrostatic ionizer experimentally. Circulating type dust testing apparatus andtalcum powders 6 µm were used in this study. Compressed air supplied to thebi-polar electrostatic ionizer was in the range of 0.01 - 0.05 MPa. Each test timewas 1800 s. As the result, in the inner parts of the ionizer, talcum powders did
not enter under all test conditions. It was also confirmed that the ion generating
ability was the same before and after the dust-proof testing.