800 Series Rate-of-Flow

The Nelson 800 Series valve can be equipped with the Rate-Of-Flow (Model D18) control to regulate the flow rate passing through the valve.

The Rate-Of-Flow works by means of a flow sensing paddle in the flow on the upstream side of the valve. It is a significant advancement in accuracy because it works independent of line pressure responding only to the flow velocity impinging upon the sensing paddle. This Rate-Of-Flow control is an option which can be combined with most other pressure and electric controls used on the 800 Series valve.

The main application for Rate-Of-Flow is during system fill to avoid unwanted water hammer or surges which can damage system pipes.  The Nelson Rate-Of-Flow control has been designed for efficiency and causes insignificant pressure loss. The control has a calibrated adjustment screw for simple setting and can work over a wide range of flow rate. The Rate-Of-Flow Control is designed to fit into the valve but can optionally be located in an adjacent upstream section of pipe.  Maintain stable hydraulic conditions with Nelson 800 Series Control Valves.

Nelson irrigation offers
a complete solution of Pressure
Control valves, featuring:

Adjustable Flow


Easy Connections


Adjustable Flow rate

The only calibrated pressure control available in the industry. Convenient for setting correct flow and for quickly checking proper flow ranges.

reliable Flow Sensing Paddle

Low friction spool works without any pressure drop.

Convenient Built-in valve

This feature can stop wild pressure swings and tune the valve for needed accuracy.

Advanced Control
  • Both reducing and sustaining function
  • No Pressure drop required to regulate
  • Widest flow available
  • Proportional throttle design
  • Pressure accuracy at different temperatures
  • Freeze proof easy clean filter
  • Valve quick pressure check fittings

Made of the toughest chemically resistant materials. 100% tested for accuracy. 

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