How to Measure a Propeller or Impeller Diameter

We are often asked how to measure a propeller diameter.  The diameter of a circle is the distance from any point on the circle straight across the center to the opposite side of the circle.  In measuring a 2-bladed or 4-bladed impeller, simply measure the point from the outer most tip of the blade across the bore, or center hole, to the outer most tip of the opposite blade.

The confusion lies when measuring a 3-bladed impeller.  In measuring a 3-bladed propeller or impeller, you do not have a blade exactly opposite across the hub’s bore.  The trick is to measure the radius and multiply it by 2 to get the diameter.  Measure the outer most tip of the blade to the center of the bore to obtain the radius.  Therefore, a propeller or impeller that measures a radius of 3” from the tip of the blade to the center of the bore will have a diameter of 6”.  (A 3” radius multiplied x 2 equals a 6” diameter.)

For additional information regarding the styles of mixing impellers or the hand of rotation, please contact INDCO’s sales department at 800-682-1660.

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We have been in business for over 30 years serving the processing mixing requirements of thousands of companies. Our specialty is small and medium size mixers for batch sizes up to 5000 gallons. We keep a large stock of component parts, and as a result can fill 95% of orders within 2 working days. Along with our full line of industrial mixing products, we can engineer fully custom modified mixing systems that meet your full specifications.

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