Condensate pumps Mechanical pumps and pumps traps
9
How to size and select Considering the inlet pressure, backpressure and filling head conditions, select the pump size which meets the capacity requirements of the application.
P 2 = 1.7 bar g Return main pressure and pipe length
Plant 1500 kg/h
Reservoir
Lift = 9.2m
0.15m Filling head
Operating pressure 5.2 bar g
MFP14
The known data
1500 kg/h
Condensate load
5.2 bar g
Steam pressure available for operating pump
6.1.27
9.2 m
Vertical lift from pump to the return piping
1.7 bar g
Pressure in the return piping (piping friction negligible)
0.15 m
Filling head on the pump available
Note: It is strongly recommended that the maximum motive/backpressure differential is between 2 - 4 bar g.
Selection example Firstly calculate the total effective lift against which condensate must be pumped. Total effective lift is calculated by adding vertical lift from the pump to return piping (9.2 m) to the pressure in the return piping (1.7 bar g). To convert pressure in the return pipe into pressure head, divide it by the conversion factor of 0.0981:- P 2 = 1.7 bar g ÷ 0.098 1 = 17.3 m Pressure head (lift) The total effective lift then becomes calculable :- 9.2 m + 17.3 m The total effective lift is 26.5 m Now that the total effective lift has been calculated, a pump can be selected by plotting the known data onto the graphs on page 6.
9.1 30
1. Plot a horizontal line from 5.2 bar g (Motive pressure). 2. Plot a line indicating 26.5 m lift. 3. From the point where the motive pressure line crosses the m lift line, drop a vertical line to the X axis. 4. Read the corresponding capacity (2400 kg/h).
Note: As the filling head is different to 0.3 m, then the capacity calculated above must be corrected by the appropriate factor selected from the table opposite.
TI-P136-02 CMGT Issue 17
Page 8 of 11
MFP14, MFP14S and MFP14SS Automatic Pumps
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