Condensate pumps

Mechanical pumps and pumps traps

How to use the sizing chart

Example

DN50 pump capacities

Flowrate kg/h

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:-

P2 = 1.7 bar g ÷ 0.098 1 = 17.3 m Pressure head (lift)

The total effective lift then becomes calculable :-

Now that the total effective lift has been calculated, a pump can be selected by plotting the known data onto the graphs on page 9.

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).

The capacity charts shown are for single pumps. The capacities should be doubled or tripled to give the capacities of the

duplex or triplex pumped packages.

Note: The MFP14-PPU packages are not supplied with a connecting condensate return manifold. Ideally each pump should have

its own dedicated return line to a vented receiver or holding tank. If the duplex pump returns are to be joined together to create a

collective return line, care should be taken to ensure that it is adequately sized to accommodate the instantaneous discharge rate

of all pumps discharging at the same time. Failure to do this may result in reduced capacity of the packaged pump unit.

9.2 m + 17.3 m

The total effective lift is 26.5 m

6.1.45

Plant

1500 kg/h

Reservoir

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.

0.3m

Filling head

P2 = 1.7barg

Return main

pressure and

pipe length

Operating

pressure

5.2 barg

Lift = 9.2m

1500kg/h

5.2 bar g

9.2 m

1.7 bar g

0.3 m

The known data

MFP14

Condensate load

Steam pressure available for operating pump

Vertical lift from pump to the return piping

Pressure in the return piping (piping friction negligible)

Filling head on the pump available

Note: It is strongly recommended that the maximum motive/

backpressure differential is between 2-4 bar g.

TI-P681-01 ST Issue 4

MFP14-PPU (Vented) Automatic Pump Packaged Units

Page 8 of 9

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