PROBLEM TO BE SOLVED: To discharge residual water within a water circuit in a dental treatment unit in a short time.SOLUTION: A suction circuit 15 for discharging the residual water is provided at the water circuit 1 of the dental treatment unit. The suction circuit 15 is formed of the solenoid valve 16 connected to the water circuit 1, a suction unit 18 for sucking the residual water in the water circuit 1 along with air, and an air-liquid separator 17 for separating the sucked air and the residual water. When the residual water is discharged, the on-off valve 3 on the side of a water pressure source 2 for supplying water to the water circuit 1 of the dental treatment unit is closed while all of the control valves 5, 7, 11, and 16 provided within the water circuit 1 are opened simultaneously with the operation of the suction circuit 15 to suck air from the respective terminals of the water circuit 1 and a check valve 14 while sucking the residual water in the water circuit 1 to introduce it into an air-liquid separator 17 to separate air and water by the air-liquid separator 17. The separated water is discharged through the water discharge pipe 21 of a piston 20 and the separated air is discharged to the atmosphere.COPYRIGHT: (C)2010,JPO&INPIT【課題】歯科診療ユニットにおける水回路内の残留水を簡単かつ短時間に排出する。【解決手段】歯科診療ユニットの水回路1に、残留水を排出する吸引回路15を設ける。吸引回路15は水回路1に接続する電磁弁16と、水回路1内の残留水を空気と共に吸引する吸引手段18と、吸引した空気と残留水とを分離する気液分離器17とからなる。残留水を排出するに際して、歯科診療ユニットの水回路1に水を供給する水圧源2側開閉弁3を閉止し、該吸引回路15の作動と同時に水回路1中に設けられた全ての制御弁5、7、11、16を開放し、水回路1の各端末および逆止弁14から空気を吸入し、空気と共に水回路1中の残留水を吸引して気液分離器17に導入し、気液分離器17にて水と空気に分離する。分離された水はスピットン20の水排出管21を経て排出し、分離された空気は大気中に放出する。【選択図】図1
