Technical data

6
Compressed Air Applications Manual | Pressure loss
The economic performance of the com-
pressed air system is of great importance
for the plant operator.
Increased flow resistance because
of dimensioning errors (e.g., pipe di-
ameter too small) or because of mis-
guided saving on investment costs
will result in a corresponding loss of
pressure and thus push up the energy
costs for the compressed air supply.
The following example shows the higher
costs for the extra energy required to
compensate for the loss of pressure.
Operating pressure 6 bar
Pipe network length 200 m
Flow rate 12 m
3
/min
DNR Pressure drop
∆p (bar)
Energy costs
€
90 0.04 153,-/a
70 0.2 614,-/a
50 0.86 3 344,-/a
It is therefore easy to calculate how long
it would take to recoup the slightly higher
expenditure for the larger dia. piping set
against the increased energy costs of the
small dia. piping.
Savings achieved during the initial
acquisition are soon swallowed up by
the high follow-up costs.
Leakage loss
It is important to know how much of the
compressed air is being lost during its
passage from the compressor to the
point of use and where it escapes.
Leaks should be located using the BEKO
leak detector.
The leakage volume is usually deter-
mined by emptying the receiver or meas-
uring the compressor’s running time. (s.
page 4, Air quantity)
Emptying of the receiver:
The receiver (VB) is filled to a given pres-
sure pA. Subsequently, it is measured
how much time t it takes before the re-
ceiver pressure comes down to pressure
pE.
Example
VB = 1000 l
pA = 8 bar
pE = 6 bar
t = 5 min
VL = l/min
VL = Leakage volume
VB x (pA - pE)
VL =
t
1 000 l x (8 - 6)
VL = = 400 l/min
5 min
Make sure that the shut-off devices at the
end of the connecting pipes are closed
so that the measurement is restricted to
leakages in the pipe network.
Pressure loss