Question 1 – What is the primary function?

The primary function is “what the valve does”.

There are nine different primary functions:

  • basic
  • on/off
  • pressure reducing (PR)
  • pressure sustaining (PS)
  • pressure reducing & pressure sustaining (PR/PS)
  • electric control
  • quick relief
  • flow control
  • level control

 

We will look at these in more detail.

 

Function: Basic

Description & common application:

  • A valve body without any accessories.
  • In other words, there is no function.
  • It is a valve body, which is often purchased by growers and dealers who want to build their own valves.

 

Benefit:

  • Build your own valves.

 

 
Function: On/off

Description & common application:

  • As the name suggests – the valve is either on or off.
  • There is no pressure regulation or flow control (the valve has no pilot).
  • Most valves have a manual selector for simple in-field on/off control.
  • Can include a hydraulic relay for remote on/off operation.

 

Benefit:

  • Enable simple in-field operation.
  • Ideal for small farms where no automation is required.

 

 
Function: Pressure reducing (PR)

Description & common application:

  • Reduces the pressure after the valve for a consistent downstream pressure, regardless of the flow rate or upstream pressure fluctuations.
  • Used in-field for each block.
  • In most irrigation systems, the majority of the valves are PR valves.

 

Benefit:

  • Ensures uniformity of each block regardless of pressure fluctuations due to distance from the pump or other factors.

 

 
Function: Pressure sustaining (PS)

Description & common application:

  • Maintains the pressure before the valve at a preset level.
  • Some irrigation components such as filters require back-pressure to function correctly. PS valves are installed downstream of these components.

 

Benefit:

  • Ensures filters and other irrigation equipment work at their maximum efficiency.

 

 
Function: Pressure reducing & pressure sustaining (PR/PS)

Description & common application:

  • Provides both pressure reducing and pressure sustaining functions in one valve.
  • Used directly after irrigation components that require back-pressure and where immediate downstream pressure reduction is required.

 

Benefit:

  • Eliminates the need for two valves by combining into a dual function valve.

 

 
Function: Electric control

Description & common application:

  • Controls your valve opening through electric control automation.
  • Selects the correct solenoid to match your control system.

 

Benefit:

  • Enables automation using a range of voltages and options.

 

 
Function: Quick relief

Description & common application:

  • Works as a safety valve for your system. Quick relief valves relieve system pressure when it rises above a preset value.
  • Unlike PR valves, quick relief valves are designed to quickly expel excess pressure when a spike occurs.
  • Install in critical stages of the irrigation system after the pump.

 

Benefit:

  • Protects your system from damage of pressure spikes.

 

 
Function: Flow control

Description & common application:

  • Restricts flow to determined flow rate. Unlike PR valves, flow control valves restrict to a specific flow through differential pressure.

 

Benefit:

  • Guarantees the same flow to multiple outlets.
  • Restricts back-flush flow from media filters for better performance during automatic cleaning.

 

 
Function: Level control

Description & common application:

  • Closes when an upper level is reached and opens when a lower set point is reached.
  • Maintains storage water levels.

 

Benefit:

  • Easy solution to prevent under/over fill.

 

 

Explore the next module, or search for a specific topic or issue.

Before using these modules, please familiarize yourself with the relevant disclaimers and additional safety and usage information contained within each module.

© 2023, Rivulis Irrigation Ltd, all rights reserved. 
Reproduction of this content in any form is prohibited without the written consent of Rivulis Irrigation Ltd.