FINAL DESIGN

The 90deg bends and tube arrived:




By comparing the diameter of the 90deg bends I have sourced with those used in Bruce Simpson's design, I have calculated a scale factor of 73.1/76 (ratios of inside diameters) that each measurement can be multiplied by to create the design I am going to follow. Effectively mine is slightly smaller than the original design.

I imputed Bruce Simpson's design into AutoCAD and applied the scale factor; this is easier than doing all the calculations by hand and also provides me with a digital copy of the design.

(3)

From using the dimensions describing the 90.deg bends in the table above provided by the manufacturer and comparing it to Bruce Simpson's design, the difference in U-bend length is (73.1/76 *190pi/2 - 160pi/2 =) 35.7mm. As the 90deg. bends have a small straight section at each end that will need cutting off, I can just leave 35.7mm on on of the bends to fill this gap.

Bruce Simpson's design:

(19)

Here is the design I will follow with labels showing how I refer to the pieces throughout this project: