In short, a booster (hydrophore) set is an assembly of equipment that pressurizes water and delivers it to the required point in situations where mains pressure is insufficient. Booster sets are widely used today in almost all residences, high-rise buildings and even industrial facilities.
A booster set consists of equipment such as pump-motor units (one, or more depending on pressure requirements), a control panel, valves, pressure gauges and an expansion tank. In other words, a booster set is not a single pump-motor unit but a system in which many pieces of equipment work together.
KSB Booster Set
Vertical-shaft centrifugal pumps are generally used in booster sets. However, due to their design, these pumps are not suited to continually starting and stopping, or to operating at very low flow rates. For this reason, the main task of the pumps in a booster set is to charge the membrane located inside the expansion tank. Although there are different types of booster sets, the most commonly used type is the one with a membrane expansion tank. The structure of these expansion tanks is as follows.
The expansion tank consists of two sections separated by a membrane. Compressed air is on one side and water on the other. A pressure drop in the system is detected by a sensor, and the line opens, sending water — compressed by the pressurized air — into the system. However, as the amount of water in the tank decreases, the volume of gas increases, so the pressure inside the tank drops. When this pressure reaches a predetermined level, the pump starts and pumps water into the tank. As the water increases, the gas begins to compress again, so the pressure inside the tank rises, and when it again reaches the predetermined level, the pump stops. This way, the pump does not run for small flow demands, and the needs of the system are still met.
HOW TO SELECT A BOOSTER SET
As with pump selection, determining flow rate and pressure is required when selecting a booster set. If we take a residential apartment building as an example, the flow calculation is as follows.
Q = A x T x B x f (litres/hour)
Q: Flow rate (litres/hour)
A: Number of families or number of apartments: A
T: Daily water consumption per person: T = 100 – 150 litres / day
B: Average number of people per family: B = 4 – 5
f: Simultaneous water usage factor
The simultaneous water usage factor is used to plan how many people will need water at the same time. The table below can be used as a basis for the calculation.
|
Simultaneous water usage factor (f) |
|
|
Up to 4 apartments |
0.66 |
|
Up to 10 apartments |
0.45 |
|
Up to 20 apartments |
0.40 |
|
Up to 50 apartments |
0.35 |
|
Up to 100 apartments |
0.30 |
|
More than 100 apartments |
0.25 |
For the discharge (delivery) head, on the other hand,
Hm = (A x B x C) + HSPECIAL + HUSAGE (mWC)
Hm: Discharge head (mWC)
A: Floor height (typically 2.8 – 3 metres for residential applications)
B: Number of floors
C: Safety factor (C=1.20 for new buildings, C=1.30 for older buildings)
HSPECIAL: Pressure required for special equipment (from the table)
HUSAGE: Pressure at point of use (HUSAGE = 15 mWC)
|
HSPECIAL: Water pressure required for special equipment |
|
|
Per water meter |
10 mWC |
|
For filtration |
15 mWC |
|
For garden irrigation with a hose |
10 mWC |
|
For garden irrigation with a sprinkler |
30 mWC |
|
For a shock (rain) shower |
15 mWC |
