Pumping Equipment

Three types of pumping equipment are generally  used:

1. Piston Pump 
2. Pneumatic Pump 
3. Squeeze Pump 

A trial mix is required to be made in the laboratory to find out the exact requirements of pumping concrete. Admixtures may be used to facilitate pumping of concrete. 

Piston Pumps 

The piston concrete pump essentially consists of a hopper  (A) equipped with remixing blades for receiving the mixed concrete, and inlet valve (B), an outlet valve (C) and a piston (D). Fresh concrete is poured in the hopper. When the piston executes the  backward or  suction stoke, the inlet valve opens while  the outlet valves closes and the concrete is drawn form the hopper. 

The Working Cycle of the Piston Concrete Pump

During  the forward or delivery stroke, the concrete is forced into the pipeline through the outlet valve  which has now opened; Piston pumps  can be operated either mechanically or hydraulically. In order to achieve steady flow of concrete, it is now usual to employ pumps  with two pistons, which operate alternately such that  while one is in suction stroke the other is delivering the concrete into pipeline. 

Pneumatic Pumps 

Pneumatic pumps essentially consist of  a pressure  vessel placer and a compressor. The concrete is delivered into the pressure  vessel and this vessel is sealed. Compressed air is now supplied through the top of the vessel. resulting in pushing out of concrete 'through a pipe at  the Bolton. which delivers concrete in the formwork.  However to bleed off air and to prevent spraying of concrete which causes  segregation  and may disturb reinforcement or damage formwork, a reblending discharge box is  provided at  the end of the line. Also to stabilise the compressed  air supply, an air  receiver tank is provided next to the compressor. 

Pneumatic Pumps 

Squeeze Pressure rumps 

The squeeze pressure pump comprises a collecting hopper with rotating blades, pumping tube,  and rollers  operating inside a pump chamber which is maintained under high vacuum. The concrete received  in the collecting hopper  is pushed  towards the pumping  tube by the rotating  blades.  The rollers press  the concrete through the tube into  a flexible material hose which runs inside the periphery of the pump  chamber. The rotating rollers which are generally hydraulically powered, rotate on the flexible hose  and squeeze out the concrete at the  top under pressure. The vacuum in  the chamber aids steady flow of concrete. Squeeze pumps are often  mounted on a truck and may deliver  concrete through a folding boom. 

Squeeze Pressure pumps