[Dust exposure and control in micro-grinding operations].

نویسنده

  • Jun Ojima
چکیده

実験では,軽作業台(W60 cm×D45 cm×H70 cm) 上に浦和工業(株)製マイクロ・グラインダ,ユーホビ ー標準セットUC100,HB1(使用電源電圧100 V,最高 回転速度 25,000 rpm(実験時は 15,000 rpmに設定), 5 mmφカーボランダム砥石GC-12,P2005装着)を設置 し,ここにアクリル製回転架台軸上に固定した円筒状被 削材(φ 8.5mm,63mmの焼成粘土管)がバネ張力によ り常に一定の力(150 gw)で押し当たるよう配置し, さらにそこへ上半身人体模型(等身大トルソー)を向き 合わせて研磨作業者の再現とした.1回の研磨時間は連 続3分間とし,研磨時間中の吸入性粉じん(PM4)の質 量濃度を柴田科学(株)製慣性衝突式個人サンプラー NWPS-254,ミニポンプ MP-Σ300(吸引流量 2.50 L/ min)およびガラス繊維ろ紙T60A20φ 25mm(最小秤 量表示0.01mgの電子天秤で秤量)によってダミー作業 者の呼吸域において測定し,マイクロ・グラインダ作業 に伴う粉じん曝露の実態を模擬的に求めた.なお,この 際の 3分間の採取における質量濃度の検出下限は 1.33mg/mであった.また,実験時の呼吸域と研磨 部位との距離間隔は10 cmとし,両者の作業台机上面か らの高さはともに30 cmとした(Fig. 2).次に,同グラ インダ作業における粉じん対策に関する実験を行い,こ れに際しては以下の三種の局所排気装置を用意した. ̧ )フード開口面サイズ 20 cm× 35 cm,フランジ幅 15 cmの一般的な外付け式フード;対面設置(Fig. 3-1) )グラインダ作業用に試作した,フード開口面サイズ 11 cm×13 cmの小型の箱型外付け式フード;下方 設置(Fig. 3-2) ̋ )開口面サイズ60 cm× 55 cm,奥行き50 cmの囲い 式フード;形状および機能が「研磨ボックス」等の商 品名で市販されているフードに近似したもの(Fig. 3-3) これらのフードの吸引風速および排気風量の測定には 日本カノマックス(株)製熱線式風速計クリモマスター Model 6511およびウエットマスタ (ー株)製風量センサ エアロQシステムを用い,それぞれのフードで排気を 行った際のダミー作業者呼吸域における粉じん濃度を測 定して,各排気フードにおける粉じん曝露抑制に必要な 排風量を比較した. 2006年11月21日受付;2007年3月2日受理 連絡先:小嶋 純 〒 214–8585 神奈川県川崎市多摩区長尾 6–21–1 独立行政法人労働安全衛生総合研究所.Correspondence to: J. Ojima, Japan National Institute of Occupational Safety and Health, 6–21–1 Nagao, Tama-ku, Kawasaki 214-8585, Japan (e-mail:[email protected]) 産衛誌2007; 49: 100–102 100

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عنوان ژورنال:
  • Sangyo eiseigaku zasshi = Journal of occupational health

دوره 49 3  شماره 

صفحات  -

تاریخ انتشار 2007