agriculture

Quick Relief (QR) Valves

Quick Relief (QR) Valves are the universal solution for protecting all types of pump stations, filters and pipelines. A QR Valve ensures that a potential pressure rise in the system will not damage the critical components of your irrigation system. This is accomplished by maintaining or continuously ‘sensing’ the pressure in the line upstream of the valve and quickly opening the valve and venting the excess pressure from the system. Once the pressure declines and returns to normal, the QR valve will return slowly to its closed position.

Product Advantages

  • Quick relief action ensures maximum security pressure. Large water passages allow the chamber of the valve to vent quickly, providing immediate protection.
  • Slow closure provides water hammer protection. The ‘no slam’ design allows the valve to close slowly, reducing the danger of water hammer when the system goes back to normal. Speed of closure is adjustable.
  • Pilot operated valve = flexibility. The set point of the valve is adjustable allowing the user the flexibility to change the setting if the requirements change. A large pressure range is covered with one spring. Straight and angle configurations and threaded, flanged or grooved connections.
  • Hydraulic valve with direct sealing diaphragm means longer functional life. No stem, shaft or bearings within the water passage.
  • Easy installation and low maintenance.

Quick Relief (QR) Valves Operation

QR VALVE OPERATION

A QR Valve is predominantly installed upstream of the filter with a tee out of the mainline. During standard operation, the QR Valve will be normally closed. Pressure in the mainline is being continuously “sensed” by the QR Valve. (See Figure 1).

During an event of pressure surge, such as immediately after pump start-up or a field valve closure, the pilot senses the rise in pressure and the QR Valve quickly opens fully in order to relieve the pressure. The desired pressure for opening is referred to as the “set point” of the valve. (See Figure 2).

The valve remains fully open until the pressure drops back to normal. When the pressure returns to normal, the valve closes at an adjustable pace. (See Figure 3).

FILTERS WITH QR VALVES

Netafim AGF Sand Media Filter tank system with an installed QR Valve and Netafim manifolds has an extended warranty – 5 years instead of the standard 2 years.

Quick Relief (QR) Valves Technical

A Quick Relief (QR) Valve ships pre-assembled by Netafim USA following strict quality standards. The QR Valve consists of a basic valve, a quick relief pilot and a needle valve (some pilots come with an integral needle valve where the needle valve is inside the pilot); Valves 6” and larger use an additional 2” Galil valve so the chamber of the valve will vent quickly even if the valve is large.

  1. Basic Valve – A basic valve consists of four simple parts – body, spring, diaphragm and bonnet – making it the simplest valve to operate and maintain. Installation is quick and easy with its unique inline design which also creates low losses at high flow rates. Available in two body material options – Iron or Bronze – both with a direct sealing natural rubber diaphragm.
  2. Pilot – a pilot is a mini-valve which ensures accuracy of the regulated pressure for hydraulic control valves. In QR Valves, when the line pressure is lower than the pilot’s spring setting (the set point), the pilot permits the passage of water into the chamber of the main valve, closing the valve. QR Valves use a CX Brass Pilot with a built-in needle valve and one spring with a pressure range of 20- 320 psi. The factory setting for this pilot is 70 psi. The Bronze QR Valve uses a 68200 Pilot with a green spring and a factory setting set point of 45 psi.
  3. Galil 2” Valve – A 2” Galil Valve is installed standard on QR Vavles that are 6” and larger to allow very large flow passages and create the required faster reaction time. The pilot will allow pressure to go out of the chamber of the Gaill Valve which will change position and allow the main QR Valve to vent.

Quick Relief (QR) Valves Ordering

SELECTION GUIDELINES

When selecting a QR Valve, the following recommended maximum flow rates should be considered to ensure proper sizing and performance.

Note: Sizing a QR Valve differs from sizing a standard inline valve. This is because the QR Valve does not work continuously, but rather only in events of pressure surges. More water is allowed through the valve that will be activated in shorter amounts of time than through an inline valve that will be operational most of the time.

Ordering Information

Choose from the following ordering charts based on valve size and flow. For non-standard products, such as QR Valves for pressures above 235 psi, call Netafim Customer Service.