CENTRIFUGE TUBES
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Technical Information
Nomogram for Computing Relative Centrifugal Force
One of the questions asked most frequently in the field of centrifugation is how does one relate revolutions per minute (R.P.M.) to relative centrifugal force (R.C.F.)? The following nomograph may be used directly or the R.C.F. may be calculated from the formula. Equation for Calculating R.C.F. R.C.F. = .00001118 x r x N 2 (R.C.F. = relative centrifugal force (gravities); r = rotating radius; N = rotating speed) Sample Calculation The relative centrifugal force (R.C.F.) at a radial distance of 8 cm from the center of centrifuge spindle when operating at a speed of 2500 R.P.M., may be determined by placing a straight edge on the nomogram connecting the 8 cm point on the Radius from Center Spindle Scale (A), with the 2500 R.P.M. point on the Speed Scale (B). The point of intersection on the Relative Centrifugal Force Scale (C), or 550 g is the relative centrifugal force (550 x 32 =17600 psi). If the desired R.C.F. is known, the speed of rotation for a given radius may be found by connecting the two points and reading the Speed Scale at intersection.
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