pump. Suction hoses fail when pumps create
more vacuum — more suction — than the hose
can resist. When this happens, the hose collapses.
Suction hoses are rigid and reinforced to keep
them from collapsing under a vacuum. Usually,
manufacturers use two reinforcement methods:
reinforcing the internal walls with helix steel wire
or integrating a hard plastic ribbing into the
outside of the hose. These reinforcements keep
the hose open and allow product to flow freely.
Most suction hoses are designed to work under
less pressure than similarly sized discharge hoses,
although the working pressures are still well
within most applications. In many applications,
suction hoses are versatile enough to be used on
both sides of a pump. But because discharge hoses
are not reinforced in the same way as suction hoses,
discharge hoses are limited for use on the pressure
side only. Discharge hoses could collapse under
the vacuum created by a pump.
Suction hoses come in blue, green, yellow,
and other colors. The colors are associated
with the plastic ribbing that is integrated and
embedded into the hose. The color of the
plastic reinforcement has no influence on
hose performance. It’s strictly cosmetic.
4.
What is the
Hose Diameter
?
Hoses have inside and outside diameters.
The inside diameter (ID) is the more
important of the two. An application system’s
delivery rate is a function of its pump’s rated
capacity and its hose ID. As a general rule,
large delivery volumes require high-ID hoses
to minimize friction loss and required pressure.
In short, your goal is to select a hose that will
deliver the needed amount of product at the
lowest practical pressure. This keeps costs
lower because higher pressures require better,
stronger, more expensive hoses.
ID also determines what size fittings the
hose should be used with.
The outside diameter (OD) is used to
determine the size of the clamp that will
secure the hose to the fitting. OD also can
be an important consideration if the hose
has to go through a hole or be used in
tight spaces.
Base your hose and tubing selections on inside diameter.
If the hose is not marked, consult the manufacturer.
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