Figure 1-1. Product batch cuts
(a) Interface head cut -made at the front end of the interface at the last gravity of pure product.
(b) Interface midpoint or center cut -- the approximate midpoint gravity between the two adjacent
EXAMPLE: (JP-4 being pushed by MOGAS). Last API gravity of JP-4 corrected to 60 degrees is 53.8, with
pure MOGAS corrected to 56.4 degrees. The midpoint between the observed API gravity is 2.6 degrees.
To determine the midpoint cut, divide 2.6 by 2 then add the results to 53.8 (for example, 2.6 / 2 = 1.3);
53.8 + 1.3 = 55.1. The midpoint cut is 55.1 degrees API between JP4 and MOGAS.
(c) Interface tail cut -Made at the last of the interface mixture before pure product.
(d) Heart cut -Pure product cut made before or after the interface.