DRAINAGE PUMP AND OPERATIONAL METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide a drainage pump and an operational method therefor for restricting consumption of pump power under air lock condition and attaining high reliability in operation and an easiness in its maintenance.SOLUTION: This invention comprises: an impeller 2 fixed to a main shaft 20 extending in a vertical direction; an underfloor pipe 3 having the main shaft 20 and the impeller 2 inserted and passed therein and that is installed below a pump installation floor 30; an over-floor pipe 7 connected to a downstream side of the underfloor pipe 3 and installed on the upper side of the pump installation floor 30; a drain communication pipe 5 installed at a downstream side of the impeller 2 to communicate with an outside part of the pump; an on-off valve 6 for opening or closing the communication part; a check valve 8 installed at the over-floor pipe 7; a detection device 9A for detecting the opening or closing operation of the check valve 8; and a control device 10A for opening the on-off valve 6 when the closing operation of the check valve 8 is detected by the detection device 9A.SELECTED DRAWING: Figure 1 【課題】エアロック状態でのポンプ動力の浪費を抑制するとともに、高い信頼性とメンテナンスの容易性を備えた排水ポンプおよびその運転方法を提供する。【解決手段】鉛直方向に沿う主軸２０に取り付けられる羽根車２、主軸２０および羽根車２が挿通され、ポンプ設置床３０の下側に配置される床下管３と、床下管３の下流側に接続され、ポンプ設置床３０の上側に配置される床上管７と、羽根車２よりも下流側に設けられ、ポンプ外部と連通する水抜き用連通管５と、前記連通部を開閉する開閉弁６と、床上管７に設けられる逆止弁８と、逆止弁８の開閉動作を検知する検知装置９Ａと、検知装置９Ａにより逆止弁８の閉動作を検知したときに開閉弁６を開弁する制御装置１０Ａと、を備える。【選択図】図１