The ‘IT’ flow rating valve prevents excess flow to consumers in water distribution networks such as: -Municipal water systems -Agriculture irrigation networks -Mining water and air supply systems -Pumping systems -Cooling plants water distribution systems The ‘IT’ flow rating valve is the ideal solution for maintaining adequate pressure in a water distribution system.

UNDERGROUND WORKINGS
The ‘IT’ flow rating valve ensures the sufficient supply of compressed air and water in the underground workings. More stopes will enjoy sufficient supply of compressed air and water if there is a limit to the usage of air or water in each single stope.

PRINCIPLE OF OPERATION
The Shuttle stays in the opened position (Drawing N^O 1) when the flow through the valve is below the excess flow rate. When the flow through the valve reaches the excess flow rate, the differential pressure (Pu-Pd) across the Shuttle causes it to move to the closed position (Drawing N^O 2). At the closed position, the set flow rate through the valve is achieved which is determined by the size of the

Bypass
Closing some or all the valves, on the downstream side of the ‘IT’ flow rating valve, resets the Shuttle to the opened position. The ‘IT’ flow rating valve doesn’t restrict the flow, irrespective of the system pressure, as long as the flow demand is below the excess flow rate. Flow restriction happens only when the flow through The ‘IT’flow rating valve reaches the excess flow rate. Automatic resetting happens when the water flow through the ‘IT’flow rating valve is reduced or stopped.

UN AFFECTED BYPRESSURE
The ‘IT’ flow rating valve is activated by the differential pressure ‘Pu’ and ‘Pd’, acting on differential areas ‘Ad’ and ‘Au’. Most of the existing flow restricting devices change the flow rating as a function of the system pressure. The ‘IT’ flow rating valve is not affected by the system upstream pressure.

FLOW RATE SETTING
The setting of the excess flow rate is changed by the size of Orifice 1, irrespective of the system pressure. The setting of the limiting flow rate is changed by the size of Orifice 2. NO INSTRUMENTS The ‘IT’ flow rating valve is powered by the line-fluid pressure with no need for external actuators, pilots,instruments or any type of external power source.

MEDIA
The ‘IT’ flow rating valve is suitable for most common O fluids and gases, not exceeding temperatures of 85 C. For special applications, please enquire at info@ngd.co.za.

MATERIALS & SPECIFICATIONS Contact the manufacturer or distributors for details.

DIMENSIONS & RATING
25NB (1”) - 600NB (24”) 10 bar (147 psi) - 250 bar (3675 psi)

VALVE ENDS
Flanges - SABS 1123, BS4504, BS10, ASME B16.34 Couplings - Tapered shoulders and other pipe couplings