Unpowered Wicking Valve

Any irrigation system with a conventional irrigation controller can be upgraded to an unpowered system where each solenoid valve is replaced by an Unpowered Wicking Valve. The conventional irrigation controller and the associated wiring become redundant.

The Unpowered Wicking Valve has a one inch (25 mm) inlet and outlet. It is also available with a 40 mm inlet and outlet (contact Measured Irrigation for a quote).

It is assumed the same drippers or sprinklers are used throughout the irrigation application. 

This amazing invention lets you set the volume of water discharged by each dripper or sprinkler during the irrigation event. The dripper discharge is independent of the flow rate of the drippers (pressure compensating or non pressure compensating). The dripper or sprinkler discharge is also independent of the water supply pressure.

The Unpowered Wicking Valve uses onsite weather conditions to control irrigation scheduling rather than the static timer intervals in conventional devices.

After irrigation and as water evaporates from the soil, water also evaporates from the container. The water in the container eventually reaches a low level corresponding to the soil drying out. The valve opens and irrigation begins. A dripper attached to the irrigation system refills the container during the irrigation. When the water in the container reaches a high level corresponding to the required watering of the plants, the valve shuts off and the cycle restarts.

Once correctly calibrated, the Unpowered Wicking Valve only sends water when plants need it and does not overwater. It responds to the same local weather conditions as the soil. Deep or shallow watering, frequent or delayed watering – all can be accommodated. You don’t have to ‘turn it off’ over winter as rain and cooler temperatures keep the container from drying out. You can leave your irrigation system unattended for weeks on end.

A polyester cloth wicks water from inside the container to outside the container to evaporate and so the cloth is always wet.

Key Features

  • Unpowered (no batteries, no wires, no solar panels, no electronics, no computers, and no WiFi)

  • If you upgrade to the Unpowered Wicking Valve, the conventional irrigation controller, the associated wiring and the solenoid valve become redundant

  • Use drippers or sprinklers, pressure compensating or non pressure compensating

  • 25 mm inlet and outlet (40 mm also available)

  • Operating pressure range 70 – 1034 kPa

  • Set the dripper discharge to any value between 200 mL and 2 L by adjusting the float

  • The dripper discharge is independent of the flow rate of the drippers

  • The dripper or sprinkler discharge is independent of the water supply pressure

  • Adjust the interval between irrigation events by adjusting the exposed surface area of the polyester cloth

  • Responds automatically to onsite evaporation and rainfall

  • The irrigation frequency increases significantly during a heat wave

  • When it rains, water enters the container and delays the start of the next irrigation event

  • Water in the container is protected from debris, algae, mosquitoes and thirsty animals

  • Simple, unpowered, and low tech, and therefore fewer things can go wrong

  • Leave your irrigation application unattended for weeks on end

The adjustable gap between the upper and lower float determines the dripper discharge

The Unpowered Wicking Valve can be purchased online from the
Measured Irrigation Shop.

Adjust the interval between irrigation events by adjusting the surface area of the polyester cloth

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