Stop valve vs. Gate valve vs. Ball valve: Who’s the winner?
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Stop valves use a rubber gasket to shut off water flow, and must be installed in the correct direction to work properly.
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Gate valves control water flow with a brass wedge.
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Ball valves use a stainless steel ball to control water flow.
There are three basic valve styles,
making this a classic case of good,
better and best (described in order
as follows). All three can be used for
water, oil or airflow control if the
casting has "WOG" stamped on it.
Stop valves are closed
by screwing a rubber gasket down
onto a seat in the middle of the
valve. Pros only use small versions
that act as shutoff valves for fixtures
such as sinks and toilets and outdoor
sillcocks. Flow is inefficient
because of the circuitous route the
fluid (water, in most cases) has to
follow. It's important to orient the
valve in the right direction with the
arrow (cast into the side of the
valve) aligned with flow direction.
That way, water flows against the
bottom of the rubber gasket. If the valve is put in backward, the flow will force the gasket away from the
top of the valve.
Gate valves are
called "full-flow" valves; there's a
direct unobstructed path for flow
right through the middle of the
valve. A wedge-shaped brass gate is
lowered into a machined slot to
close the valve. They should either
be completely open or completely
closed. Water flowing through a
partially open gate valve wears away
the metal and causes the valve to fail
Ball valves contain
a finely machined stainless steel ball
with a hole drilled through the center
that pivots in plastic bushings.
Like the gate valve, it's a full-flow
valve. The hard steel allows this
valve to be partially open without
wearing out. In the closed position,
the lever is perpendicular to the
pipes; in the open position it’s parallel,
so a glance will tell you if it's
open or not. The downside? If the
pipes are tight against the wall, you
may not be able to operate the lever.