Hydraulic ram
Hydraulic rams, or hydrams, are relatively simple machines, with the help of which water can be lifted to a higher geodetic level or pressure level.
The kinetic energy contained in flowing water, retained by sudden closing of a valve, generates surge pressure strong enough to force part of the water into an accumulator (air vessel). The delivery pipe (riser) is fed from here.
See Fig. 1 Hydraulic ram
After opening the valve, the water column is once again placed in motion under the influence of a slight drop, so that the process continually repeats.
| Example: | Drive pipe | Riser | Outlet pipe |
| Height of water column m | 27 | 164 | - |
| Volume flow rate m³/h | 15 | 1.7 | 13.3 |
This type of transport, though transient, uses no outside energy and, apart from occasional inspections of the two valves (i.e. the only moving parts), is maintenance-free. The hydraulic ram is therefore particularly suitable for irrigation purposes in developing countries.
