16
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January - February 2020
|
www
.
machinerylubrication.com
Logic valves can be diffi-
cult to understand. We
even seem to have trouble
agreeing on what to call
them. Many people describe them as
"cartridge" valves. is is not incor-
rect, as they are in fact cartridge-type
valves. Even the manufacturers
typically call them this. I have also
heard them referred to as "poppet"
valves. Again, this is not incorrect.
ey do make a full-beveled seat
that allows no bypassing, so they
definitely can be classified in this
manner. However, I prefer "logic"
valves, because "cartridge" does
not distinguish them from other
cartridge-type valves, such as a relief
valve or flow control mounted in a
manifold. Likewise, "poppet" does
not differentiate them from other
types of poppet valves. Whatever
you prefer to call them, they are
becoming increasingly popular, so
it's important to understand them as
hydraulic systems evolve.
Advantages
of Logic Valves
Logic valves have distinct advan-
tages, primarily because they are
mounted in a manifold. is enables
them to cope with high pressures
better than conventional hydraulic
plumbing. Over time, hydraulic
systems are being operated at higher
and higher pressures. is allows the
use of smaller actuators, making the
systems much more efficient. Now,
more of the energy that goes into
the system can be directed to the
product, and less is wasted on the
mechanical machine operation. is
Understanding Logic Valves
in Hydraulic Systems
HYDRAULICS
Jack Weeks
|
GPM Hydraulic Consulting
Logic valves
are becoming
increasingly
popular, so
it's important
to understand
them as
hydraulic
systems
evolve.
Figure 1. A schematic symbol for a logic valve alongside the valve it represents
