The construction of micro hydropower station-Head measurement
There are many Head measuring method, here only to introduce a simple and applicable method. With simple tools, convenient operation, easy to understand, everyone can master the operation method, namely the water pressure altimeter measurement.
The water pressure altimeter measurement is by a pressure gauge and a 20 meters plastic pipe. The Principle: the pressure gauge to the function of the pressure, the characteristics of plastic tube can hold water, when the plastic tube filled with water, and then formed certain elevation difference, on the pressure gauge will say a pressure values. The basic unit of the pressure gauge using MPa (MPa) as the measuring unit. It can be converted to Meter(M). The list below:
Pressure (0.04 0.08 0.12 0.16 MPa) =Elevation Head (4 8 12 16 meter)
Tools: the water pressure altimeter (pressure gauge), tape measure, wood stakes, notebooks, pens and a knife.
Operation: depending on the terrain from a water source, available forebay as a starting point, the hydro-generator equipment as the end. Divided into several segments, indicated by a wood stake, measurement, and recorded for buying the pressure tube data. Two people grasp the ends of the water pressure gauge respectively, the transparent plastic tube filled with water, since in measurement, the pipe inlet part people stand high (first stake), the people with pressure gauge standing low site (second stake), as differential water pressure in the tube, the pressure gauge clock work. Referring to the clock data for Head differential, convert Mpa to meter and recorded. Repeat, with the sectional measurement of elevation difference value together, get the Head gap value.
The measuring tool is convenient, simple science does not need complex computation; this is the suitable way for micro hydropower mountainous area. (Figure below)
Net Head and Gross head
By recording these actual measurements, you have determined Gross Head. the effective Head is actually lower when water begins to flow, due to pipeline (penstock) friction. A properly designed pipeline will yield a Net Head of about 85%-90% of the Gross Head you measured, and also Head between reaction turbine and action turbine are not the same, all these factors should be consider into our design, lots of factor will affect the final design, you need a project designer to help, send us your project detail, we will help you.