Single-Shaft Eccentric Screw Pump

Abstract

A double/triple-thread single-shaft eccentric screw pump is provided. The rotor of the pump overhangs little in comparison with the flange type connecting structure. The whole length of the pump is short, and the pump casing of the pump is short and small in diameter, so that the pump is small in size and light in weight. One end of a flexible rod is tapered and has a tapped hole formed at its axis. One end of the rotor has a tapered bore formed at its axis, into which the tapered end of the flexible rod is fitted. The rotor has a through bore formed at its axis, through which a tension bolt extends from the other end of the rotor. The tension bolt has a front threaded end, which is screwed into and fastened to the tapped hole of the flexible rod.

1 . A single-shaft eccentric screw pump comprising a pump body, a pump casing, and a flexible rod, the pump body including an externally double-threaded rotor elliptic in section and a stator having an internally triple-threaded bore in the shape of a substantially equilateral triangle in aperture section, the rotor being in engagement with the stator bore, the flexible rod coupling the rotor and a drive shaft together, the drive shaft being connected to a drive unit, the single-shaft eccentric screw pump being characterized by:
 the flexible rod being tapered at least one end thereof, the tapered end having a tapped hole formed at an axis thereof;   the rotor or the drive shaft having a tapered bore formed at an axis thereof, the tapered end being fitted into the tapered bore;   the rotor or the drive shaft further having a through bore formed at the axis thereof;   a tension bolt extending through the through bore from the other end of the rotor; and   the tension bolt having a front threaded end, the threaded end being screwed into and fastened to the tapped hole in the tapered end of the flexible rod so as to connect the rod and the rotor or the drive shaft together.   
   
   
       2 . The single-shaft eccentric screw pump as claimed in  claim 1 , further characterized by:
 the flexible rod being tapered at both ends thereof, each of the tapered ends having a tapped hole formed at the axis thereof;   each of the rotor and the drive shaft having a tapered bore formed at the axis thereof, one of the tapered ends being fitted into the tapered bore;   each of the rotor and the drive shaft further having a through bore formed at an axis thereof;   a first tension bolt extending through the through bore of the rotor from the other end of the rotor;   a second tension bolt extending through the through bore of the drive shaft from the other end of the rotor; and   each of the tension bolts having a front threaded end, the threaded end being screwed into and fastened to the tapped hole in one of the tapered ends of the flexible rod so as to connect the rod to the rotor and the drive shaft.   
   
   
       3 . The single-shaft eccentric screw pump as claimed in  claim 1 , further characterized by:
 the first tension bolt further having a rear threaded end;   a nut engaging with the rear threaded end;   a cover fitted to the end of the rotor which is away from the flexible rod; and   the cover covering the nut.   
   
   
       4 . The single-shaft eccentric screw pump as claimed in  claim 1 , further characterized in that one end of the flexible rod is connected to a central portion of the rotor or a central portion of the drive shaft at any point between both ends of the rotor or any point between both ends of the drive shaft. 
   
   
       5 . The single-shaft eccentric screw pump as claimed in  claim 2 , further characterized by:
 the first tension bolt further having a rear threaded end;   a nut engaging with the rear threaded end;   a cover fitted to the end of the rotor which is away from the flexible rod; and   the cover covering the nut.   
   
   
       6 . The single-shaft eccentric screw pump as claimed in  claim 2 , further characterized in that one end of the flexible rod is connected to a central portion of the rotor or a central portion of the drive shaft at any point between both ends of the rotor or any point between both ends of the drive shaft.