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Key to Schematic Diagram

THE PRESSURE REDUCING STATION (Back To Top)

The pressure reducing station reduces the station's upstream pressure to the required downstream pressure, irrespective of the flow rate through the station. A main pressure reducing station should consist on a dual arrangement with a complete running leg and a complete standby leg.

FUNCTIONS OF THE PRESSURE REDUCING STATION (Back To Top)

The main functions of the pressure reducing station are: -

• Reduces the station's upstream pressure to the required downstream pressure, irrespective of the flow rate through the station.
• Shutoffs the flow through the station on pipe's burst occurrence downstream the station. (Normally indicated by a flow surge)
• Shutoffs the flow through the station on pressure rising occurrence downstream the station.
• Alternatively opens a bypass fluid passage to reduce pressure surges.
• Have an isolating valve upstream and downstream the station.
• Displays the station's downstream and upstream pressures by means of pressure gauges.

TECHNICAL REQUIREMENTS - Pressure Reducing/Control Valves (Back To Top)

Pressure control or Pressure reducing valves should comply with the following requirements: -

• The valve should preferably derive its actuating power, directly from the high-pressure water in the pipeline.
• The valve must close automatically under no-flow or high-pressure conditions.
• Mine water-deteriorating conditions such as scaling or corrosion should not change the pre-set control parameters.
• Closing time of the valve should be adjustable for the purpose of preventing severe water hammer during the valve closure.
• The pressure reduction process should not damage the valve seating area.
• All pressure reduction and pressure control must be achieved by utilizing a single valve. Pressure reduction by valves in series arrangement is not recommended.
• The valve should operate at any flow rate without developing cavitation conditions.
• The valve should maintain a constant downstream pressure irrespective of the flow rate.
• The valve should not develop hunting behavior under low flow rate conditions.