Using Performance Curves to Find Head

A system-head curve can be superimposed on the headcapacity curve of a Discflo pump. The point of intersection will give you the operating point of the specific pump with the specific system.

EXAMPLE 1A: (in US units) Determine the total dynamic head for a 806 pump with the following handling characteristics. Fig 1.7 shows a system-head curve superimposed on the head-capacity curve for this disc pump:
Discflo Performance Curves to Find Head
Flow rate: 500 GPM
Specific gravity: 1.15
Viscosity: 500 cPs
Solid size: 0.25"
Solids concentration: 20%

The total dynamic head is as follows:

Total length of pipe = 150 ft
Vertical height = 50 ft
New steel pipe of diameter = 6"
Pipe fittings:
(4) elbows = 7.5 ft (equivalent length of straight pipe)
(2) gate valves = 1.6 ft (equivalent length of straight pipe)
(1) swing check valve = 7.6 ft (equivalent length of straight pipe)
Total = 16.7 ft (equivalent length of straight pipe)
Total dynamic head at 500 GPM = 16.7 ft + 50 ft height
````````````````````````````````````````````= 67 ft,

as shown at the intersection of the system-head and the capacity-head curves in Fig 1.7.