MIX SCALE – SCALE OF AGITATION
Mix Scale is used to quantify the mixing intensity needed for a given process as well as provide a frame of reference for mixing scale-up.
This 1-to-10 agitation scale is based on the impeller pumping capacity divided by the tank cross-sectional area, resulting in a bulk fluid velocity. This velocity, in feet/minute (ft/min.), then is divided by 6 to obtain the scale of agitation. This simple 1-to-10 scale has been used for decades as a valuable tool for quickly describing mixing intensity.
| TYPE | DESCRIPTION | MIXSCALE | TYPICAL APPLICATION |
|---|---|---|---|
MILD |
LITTLE SURFACE MOTION, NO SPLASH, MILD RIPPLE | 1 | MOST STORAGE APPLICATIONS.LOW VISCOSITY BLENDING OF LIQUIDS WITH MINIMAL DIFFERENCE IN SPG'S & VISCOSITY. VISCOSITY IN THE RANGE OF 100 CPS AND BELOW. LIGHT SOLIDS MOVING ON TANK BOTTOM, NO SUSPENSION. |
| 2 | |||
| 3 | |||
MODERATE |
SLOW ROLLING LIQUID SURFACE OCCASIONAL WAVE WITH LITTLE SPLASH | 4 | LOW TO MEDIUM VISCOSITY BLENDING WITH SP.G. DIFFERENCE LESS THAN 0.6 WITH VISCOSITIES GENERALLY BELOW 5000 CPS. SOLIDS MOVING OFF BOTTOM BUT NOT SUSPENDED ANYMORE THAN 20% THROUGHOUT TANK. EASY HEAT TRANSFER. |
| 5 | |||
| 6 | |||
VIGOROUS |
SOME SPLASH WITH BOILING ACTION AT SURFACE, OCCASIONAL VORTEX | 7 | MEDIUM VISCOSITY LIQUID/LIQUID BLENDING. SP.G. DIFFERENCE LESS THAN .85 WITH VISCOSITY LESS THAN 10,000 CPS. MODERATELY SUSPENDED SOLIDS THROUGHOUT 75% ON TANK. GOOD HEAT TRANSFER. |
| 8 | |||
VIOLENT |
SPLASHING AND LARGE WAVE FORMATIONS, ERRATIC VORTEXING | 9 | LIQUIDS WITH VISCOSITIES LESS THAN 25,000 CPS WITH SP.G. DIFFERENCE OF 1.0. SOLIDS SUSPENDED TO COMPLETE UNIFORMITY. |
| 10 |
