The contribution of UFR in measuring water volume by water meter in a single household

A test rig was set up in the Hydraulic Laboratory of the Faculty of Civil Engineering in Subotica (Republic of Serbia) to model two-outlet water supply systems (consumption was measured by water meters no. 2 and 3), with total flow rate lower than Q
_n
. According to the applied pressure and flow, the system models the water supply pipeline of a single household. The rated diameter of water meters is 20 mm, manufactured by Potiski vodovodi/Tisa Region Waterworks/ Ltd. Horgos (Republic of Serbia). The characteristic water meter flow rates are: flow activating the water meter propeller (Q
_a
) is between 0,0052 and 0,0067 m
³
/h, Q
_min
=0,05 m
³
/h, Q
_t
=0,2 m
³
/h and Q
_n
=2,5 m
³
/h. Upstream to water meter no. 3 a UFR was installed, manufactured by A.R.I. from Jerusalem (Israel), having a rated diameter of 20 mm, product type T30. Water supply system losses with discharges Q
₃
<;Q
_min
are modelled at water meter no. 3. Water flow at water meter no. 2 was either Q
₂
=0 or Q
_min
≤Q
₂
≤Q
_n
. According to the measurements, the most significant contribution of the UFR in measuring water volume by a water meter of a single household is in the discharge range of Q
_a
, just prior to activation of the water meter propeller: a) 70,47% at flow rates Q
₂
=0 and Q
₃
=0,005-0,0052 m
³
/h, and b) 7,47% at flow rates Q
₂
=0,0559-0,0577 m
³
/h and Q
₃
=0,0049-0,0050 m
³
/h respectively.