Citation

Choi K, Choi M, Yanagida K, Shiramatsu K. J. Japan Soc. Safety Eng. 2021; 60(2): 85-92.

Vernacular Title

可燃性液体塗料用静電塗装ガンの着火性評価方法に関する実験的研究

Copyright

(Copyright © 2021, Japan Society for Safety Engineering)

DOI

10.18943/safety.60.2_85

PMID

unavailable

Abstract

In this study, a novel explosion test equipment along with a testing methodology were introduced to evaluate the ignitability of electrostatic coating guns for ignitable liquid coating materials. The explosion test equipment consisted of an explosion chamber, an electrostatic coating gun, a grounded metal ball electrode with 25 mm in diameter, a small sized robot, a gas concentration meter, and a personal computer to control the robot. The explosion chamber was filled with air containing approximately 5.25 vol ％ propane. Three kinds of electrostatic coating guns （S1 to S3） were used for ignition tests. The results showed that the safety function device effectively prevented ignitions for all the electrostatic coating guns. However, an ignition was detected on the S2 electrostatic coating gun when the safety function device was off. The ignition was attributed to a non-grounded metal paint spray part existing near the needle electrode. The results obtained by employing the explosion test equipment and method introduced in this study were confirmed to be valid and reproducible．

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本研究では液体用静電塗装ガンの着火性評価の試験方法として，爆発容器に試験用プロパンガスを充填し，3 品目（S1 ～S3）の静電塗装ガンに異常放電を発生させて着火の有無を判断しながら，その妥当性および着火の原因を調べた．爆発実験装置は主に爆発容器，静電塗装ガン，接地鋼球電極，小型ロボット，試験用ガス，ガス濃度計，制御用ノートパソコン等から構成されている．結果によると，いずれの静電塗装ガンにおいても安全機能装置が着火爆発防止に有効であり，着火・爆発は起こらなかった．しかし，安全機能装置を停止させた状態の実験では，一部の静電塗装ガン（S2）で着火・爆発が起きた．これは針電極の近傍にある接地されていない金属製の塗料噴霧部が原因であることが明らかになった．なお，本研究で製作した爆発容器と方法を用いて，安全性を確保しながら再現性に優れた結果が得られ，その妥当性が確認できた．

Language: ja

Keywords

electrostatic discharges; Electrostatic spraying gun; ignition; liquid; safety; 安全; 液体; 着火; 静電塗装; 静電気放電