| 摘要 |
A pump for a reverse circulation rotary drilling rig is described which is designed to prevent drilling fluid from coming into contact with the pump bearing. A generally cylindrical-shaped housing is secured to the lower end of the Kelly bar and is in fluid communication with the interior thereof. The housing defines first and second spaced-apart compartment areas having a fluid passageway extending therebetween at one side of the housing. A rotatable shaft extends downwardly through the Kelly bar, through the first compartment area, through the space between the compartment areas and into the second compartment area. An impeller is mounted in the second compartment area and is designed, upon rotation of the shaft, to pump drilling fluid upwardly through the pipe string, outwardly through the second compartment area, through the fluid passageway and the first compartment area upwardly through the Kelly bar. A bearing is operatively secured to the housing within the first compartment area for rotatably supporting the shaft. A tube extends downwardly through the Kelly bar around the shaft and has its lower end extending around the bearing to isolate the bearing and the shaft from the drilling fluid which could cause damage to the bearing if the fluid came into contact with same.
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