Air turbine handpiece

Abstract

An air turbine handpiece having: a head portion with built-in free turbine blade, a neck portion installed consecutively with the head portion and grasped by an operator, a grip portion installed consecutively with the neck portion, an air supply duct for driving the turbine blade, and an exhaust duct for exhausting the air. The exhaust duct is provided with a reflux duct, open at one end to the exhaust duct, and open at the other end to the turbine room as the exhaust exit, a value in which an aperture at the reflux exit of the reflux duct is divided by an aperture in the air supply port of the air supply duct, becomes one or less, and the reflux exit of the reflux duct is opened to the turbine room near the air supply port between the air supply port and the exhaust exit.

1 . Air turbine handpiece comprising a head portion forming therein a turbine room, in which a rotatable turbine blade is provided; a neck portion installed consecutively with the head portion and grasped by an operator; a grip portion installed consecutively with the neck portion behind thereof; an air supply duct for charging air from an air supply port to drive the turbine blade; and an exhaust duct for exhausting the air from the exhaust vent after rotating the turbine blade by the charged air; wherein the exhaust duct is provided with a reflux duct for the exhausting, one end of the reflux dust is opened to the exhaust dust as an reflux entry, and the other end of the reflux dust is opened to the turbine dust as the exhaust exit. 
     
     
         2 . The air turbine handpiece as claimed in  claim 1 , wherein the reflux duct is constituted in such a manner that a value in which an aperture at the reflux exit of the reflux duct is divided by an aperture in the air supply port of the air supply duct, becomes one or less, and the reflux exit of the reflux duct is opened to the turbine room near the air supply port between the air supply port and the exhaust exit. 
     
     
         3 . The air turbine handpiece as claimed in  claim 1 , wherein the reflux duct is constituted in such a manner that when the aperture in the air supply port of the air supply duct is assumed to be D0, and the aperture at the reflux exit is assumed to be D1, the aperture at the reflux exit of the reflux duct is set as D0:D1=1:0.62 to 0.92, and the reflux exit of the reflux duct is opened to the turbine room near the air supply port between the air supply port and the exhaust exit. 
     
     
         4 . The air turbine handpiece as claimed in  claim 3 , wherein the reflux duct is constituted in such a manner that when the aperture in the air supply port of the air supply duct is assumed to be D0, and the aperture at the reflux exit is assumed to be D1, the aperture at the reflux exit of the reflux duct is set as D0:D1=1:0.77, and the reflux exit of the reflux duct is opened to the turbine room near the air supply port between the air supply port and the exhaust exit. 
     
     
         5 . The air turbine handpiece as claimed in  claim 1 , wherein the reflux duct is installed consecutively with another reflux duct through the reflux entrance for exhausting opened to the exhaust tube, and the reflux exit of the reflux duct is opened to the turbine room of the air supply port near in the tip of the nozzle installed consecutively to the exit side of the air supply duct. 
     
     
         6 . An air turbine handpiece comprising a head portion forming therein a turbine room, in which a rotatable turbine blade is provided; a neck portion installed consecutively with the head portion and grasped by an operator; a grip portion installed consecutively with the neck portion behind thereof; an air supply duct for charging air from an air supply port to drive the turbine blade; and an exhaust duct for exhausting the air from the exhaust port after rotating the turbine blade by the charged air; wherein the air supply duct is installed consecutively with a nozzle, and the exhaust duct is provided with a reflux duct, one end of the reflux duct is opened to the exhaust duct as an reflux entry, and the other end of the reflux duct is opened to near the air supply port of the nozzle as an exhaust exit.