Potter-Elvehjem Tissue Grinders, PTFE Pestle and Unground Glass Tube

Tissue grinders produce homogenates by a combination of shearing and compression actions. The tissue sample is progressively ground (sheared) into smaller pieces at the rounded and of the pestle as the spinning pestle is lowered into the tube. As the pestle is forced lower into the tube, the sample is displaced and forced between the straight outside wall of the pestle and the inside wall of the tube, compressing the tissue cells untill they rupture. When the tube is pulled away from the pestle, a slight vacuum is created that pulls the sample back past the compression area, resulting in an additional homogenization stroke.

The degree of homogenization is controlled by the clearance between the pestle's and tube's cyclindrical section (radial distance usually 0.002 to 0.003 inches), the rotational speed of the pestle and the number of compression strokes made.

• Sizes 21 to 24 have radial serrations on the lower portion of the pestle to deliver the homogenate into the cylindrical portion of the tube
• Clearance between pestles and tubes is 0.004 to 0.006 in.
• Replacement components are available and completely interchangeable
• The lower portion of the pestle is round shaped
• Ground glass pestle versions are suited for connective tissues
• PTFE pestle versions are used with softer tissues