The characteristic curves of the pumps are usually at height - feet or meters - and a conversion to pressure scales commonly used in pressure gauge - such as psi or bar - may be necessary.
Converting head to pressure
Converting the head into feet for pressure in psi
The characteristic curves of the pumps in feet of manometric height can be converted to pressure - psi - By the expression:
p = 0,433 h SG (1)
Where
p = pressure (psi)
H = Head (ft)
SG = specific fluid gravity
Converting the head into metros for pressure in bar
The characteristic curves of the pumps in metros of manometric height can be converted to pressure - bar - By the expression:
p = 0,0981 h SG (2)
Where
H = Head (m)
p = pressure (bar)
Converting the load to metros for pressure in kg/cm 2
The characteristic curves of the pumps in metros of manometric height can be converted to pressure - kg/cm 2 - By the expression:
p = 0,1 h SG (2b)
Where
H = Head (m)
P = pressure ( kg/ cm2 )
Converting pressure to head
As the gauge is usually calibrated in pressure - PSI or bar - A conversion to the heads commonly used in bombs may be required - such as feet or meters.
Converting pressure to psi head feet
h = 2,31 p / SG (3)
Where
H = Head (ft)
p = pressure (psi)
Converting pressure to bar head metro
h = p 10,197 / SG (4)
Where
H = Head (m)
p = pressure (bar)
Pressure conversion to kg/cm 2 for height in metros
h = P 10 / SG (4b)
Where
H = Head (m)
p = pressure (kg/cm 2 )
Example - pump head conversion - feet - In pressure - psi
The pressure - psi – of a bomba water operating with a head of 120 feet It can be calculated with Eq. 1 How:
p = 0.433 (120 pumps) (1)
= 52psi _
Example - Pressure Conversion - psi – pump head - feet
The load in feet water column can be calculated from the pressure of 100 psi with Eq. 3 as:
H = 2,31 (100 PSI) / (1)
= 231 Feet
Where specific gravity of water = 1 .
Water feet from the head in psi
| Head (ft) |
Pressure (psi) |
|---|---|
| 1 | 0,43 |
| 2 | 0,87 |
| 3 | 1,30 |
| 4 | 1,73 |
| 5 | 2.17 |
| 6 | 2,60 |
| 7 | 3,03 |
| 8 | 3,46 |
| 9 | 3,90 |
| 10 | 4,33 |
| 20 | 8,66 |
| 30 | 13,0 |
| 40 | 17,3 |
| 50 | 21,7 |
| 60 | 26,0 |
| 70 | 30,3 |
| 80 | 34,7 |
| 90 | 39,0 |
| 100 | 43,3 |
| 120 | 52,0 |
| 140 | 60,6 |
| 160 | 69,3 |
| 180 | 78,0 |
| 200 | 86,6 |
| 250 | 108 |
| 300 | 130 |
| 350 | 152 |
| 400 | 173 |
| 500 | 217 |
| 600 | 260 |
| 700 | 303 |
| 800 | 346 |
| 900 | 390 |
| 1000 | 433 |
Source: https://www.engineeringtoolbox.com/pump-head-pressure-d_663.html
