Tips on SGB Proportioning Accuracy

By adopting gravimetric technology, SGB series is able to weigh materials one by one then fulfill proportioning with weight values of each batch. This technique can not only obtain a large proportion capacity, but reach high proportioning accuracy.

Proportioning accuracy of SGB refers to the percentage of deviation between material actual proportion value and theoretical value.

Proportioning accuracy is an important parameter in SGB to affect whether it were quality goods or not. Normally standard proportion accuracy of Shini SGB is: ±0.3% (without auger discharge valve or other micro discharge valves) and ±0.1% (with auger discharge valve or other micro discharge valves). To know the exact meaning of two figures above is quite important.

Maximum accuracy of SGB is the error accuracy relative to batch weight. Below we offer two examples with respect to batch weight and material to explain what does maximum accuracy of SGB mean. (Default conditions from hopper 1 to hopper 4 are virgin material, reclaim, masterbatch and additives)

• Under the calculation for batch weight, we assume each weighing for SGB is 1000g and the proportion of four kinds of material is 55%, 40%, 3.5% and 1.5%. Accordingly, the weight of each material can be listed: 1000*55%=550g, 1000*40%=400g, 1000*3.5%=35g and 1000*1.5%=15g. Based on SGB original proportion accuracy, the range of each material proportion weight is shown as below:

(550-1000*0.3%=547g)~(550+1000*0.3%=553g)
(400-1000*0.3%=397g)~(400+1000*0.3%=403g)
(35-1000*0.1%=34g）~（35+1000*0.1%=36g)
(15-1000*0.1%=14g）~（15+1000*0.1%=16g)

• Under the calculation for material, we assume each weighing for SGB is 1000g and the proportion of four kinds of material is 55%, 40%, 3.5% and 1.5%. Accordingly, the weight of each material can be listed: 1000*55%=550g, 1000*40%=400g, 1000*55%*3.5%=19.25g and 1000*1.5%=15g. Based on SGB original proportion accuracy, the range of each material proportion weight is shown as below:

(550-1000*0.3%=547g)~(550+1000*0.3%=553g)
(400-1000*0.3%=397g)~(400+1000*0.3%=403g)
(19.25-1000*0.1%=18.25g）~（19.25+1000*0.1%=20.25g)
(15-1000*0.1%=14g）~（15+1000*0.1%=16g)

According to values above, error value of SGB actual discharge amount is only related to theoretical batch weight, having nothing to do with theoretical discharge amount of each material.