We know, to pump concrete to both long vertical and horizontal distance, a strong and efficient pump is required. No doubt about it, but a suitable pipeline and good coupling system are also important to have a trouble free pumping operation. For a particular pumping pressure, a correct pipeline diameter having sufficient wall thickness is required. A poor pipeline results leakage of grout to cause concrete blockage and subsequent problems in pumping.
It should keep in mind that concrete is abrasive for both pipeline and coupling and flowing such abrasive material with pressure, produce heavy wearing to the walls of pipe and couplings. Diameter of pipeline and its wall thickness have to match with pumping and designed placing rate. Normally 125 mm pipeline is used to convey maximum pumping work.
There have some exceptions, for horizontal pumping of long distance, a pipeline system of large diameter is chosen, in case of high pimping pressure, to take into account a flow of less resistance. But for pumping concrete against gravity to height, a smaller suitable diameter of pipeline is chosen, considering the fact of concrete weight and gravity.
As an example, we can guide engineers, for pumping less than 200 m having 30 m3/h through pipeline, 100 mm diameter is enough. But for pumping greater than 500 m distance the diameter should be 150 mm.
The pipeline diameter also depends on aggregate size. Normally diameter is expected to be 3-4 times of largest aggregate size. Say to pump a concrete of 30 mm aggregate, a 90-120 mm diameter pipeline is considered good. But in practical case 125 mm pipeline is used.