pivoting stem design used in all Edstrom valves is easy to understand when you
look at the cross sectional drawings of the valve below.
section view in closed and open position
In the normal, closed
position, the head of the stem is held securely against the O-ring by the
elastic diaphragm, preventing water from flowing under the stem head and out the
When the end of the stem
is moved in any direction by biting, licking or pecking, the head of the stem
pivots on the O-ring. One side of the head lifts off the O-ring and allows water
to flow under it and out to the animal's mouth or beak.
When the animal releases
the end of the stem, the elasticity of the silicone rubber diaphragm located
behind the stem head pushes the head back to the closed position, stopping the
flow of water.
many advantages and benefits of this simple valve design.
Because a soft O-ring
provides the water shut-off seal, the valves are extremely resistant to
leaks. Dissolved minerals in the water (hard water and iron) do not cause
the valve to leak as with other types of waterers.However,
we do recommend that particles in the water be removed by filtration.
The Edstrom valve can
be easily disassembled for cleaning or replacement of parts.
The Edstrom valve is
not sensitive to water supply pressure. It will operate with pressures as
low as 1/8 psi and as high as 10 psi. At higher pressures the force required
to actuate the valve increases. An operating pressure of 3-5 psi is
recommended for easy operation by most species.
The pivoting head of
the valve is held tightly closed by the elasticity of the silicone
diaphragm, preventing possible backflow of water and contamination into the
water supply line to the rest of your facility.
Local plumbing codes may require that you install an Auto-Air Break
Valve at the point you connect your automated watering system to your
domestic water supply. Use an approved device for this purpose.
A small droplet of
water normally remains at the end of the valve after its operation. Animals
and birds quickly locate this water, and in their efforts to drink it, move
the stem, releasing more water to drink.They
train themselves to drink from the Edstrom Valve in no time at all.