Adjustable height magnetic stirrer

Claim 1

An improved magnetic stirring apparatus comprising: a vessel having walls, a bottom and an opening; a stirrer having a shaft and an attached magnetic impeller; a means for rotating the magnetic impeller; and a closure wherein the improvement is characterized by: (a) a closure having an opening; (b) a hollow adjustment support member dimensioned and configured to surround the opening in the closure: (i) is connected to the closure about the opening; (ii) upwardly projects from the closure; and (iii) is at least partially threaded on the interior; (c) a hollow sleeve being dimensioned and configured: (i) with corresponding threads to screw into the adjustment support; and (ii) with an interior diameter that can receive the shaft; (d) an annular lower bearing surface: (i) attached to the interior of the sleeve; and (ii) having an opening dimensioned and configured to receive the shaft; (e) a rotating upper bearing surface: (i) having larger diameter than the opening in the lower bearing surface; and (ii) which downwardly engages the lower bearing surface; (f) the shaft: (i) being connected to the upper bearing surface; and (ii) projecting downwardly, through the lower bearing surface and the sleeve, into the vessel; (g) an adjustment means having: (i) an upper portion dimensioned and configured to engage a portion of the sleeve and permit the upper bearing to rotate; (ii) a lower portion dimensioned and configured to slide over the exterior of the support; and whereby when the means is placed over the support and engages the sleeve, the impeller height can be adjusted by turning the means.