TDH pri centrifugalni pumpi

[_jasna_]

Zivijo.
Mene pa zanima ce vemo da mora bit tdh pumpe recimo 80. Kaj potem je boljse ce ima pumpa vec ali manj tdh-ja?
Najlepsa hvala za odgovor. Srecno.

[xstrojnik]

Total developed head (TDH)
TDH is the total resistance against which pump is working. This resistance is comprised of three general factors: Dynamic Head, Static Head and Velocity Head.

Dynamic Head Is the flow resistance (head) created by friction in piping, valves, fittings and liquid viscosity.* To derive maximum flow from a pump, avoid using piping smaller than the pumps' discharge (increasing the size of the outlet piping will decrease flow resistance). Street "ells" and globe valves should be avoided because they restrict flow. When the size of the piping is smaller than the pumps' discharge, or when long runs are required (over 20 feet), plumbing friction may easily comprise 50% or more of the TDH.

Static Head is the height (head) required to which liquid must be raised. Note: When using the flow charts in the pump selection, both Dynamic Head and Static Head must be included in estimating the TDH against which the pump will operate.

Velocity Head is the pressure (head) required to accelerate the liquid to it's flow velocity. This is usually a negligible factor of TDH and can be disregarded unless piping is smaller than the pump discharge and/or flow velocities are greater than 15 feet per second.

*The higher the viscosity of a liquid, the more resistance it has to flow. Pump viscosities throughout this information given are stated in SSU's (saybolt second universal). 70° F water = 31 SSU. Light hydraulic oil = 350 SSU. #10 oil = 500 SSU. When choosing pumps, be sure to note the designated fluid viscosity.

Upam, da sem kaj pomagal...