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Providing Engineered Solutions in Pneumatics,
Hydraulics, Motion Controls and Systems
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MAC VALVES
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Small
3 Way Valve
The
Mac direct acting poppet valve adopts a unique solenoid
design, coupled with other special features. This technology
is used in the smaller Mac valves, and in the larger spool
valves as a solenoid air pilot force.
A
short stroke from the solenoid ensures a high shifting force
to energize, allowing for a strong return spring and hence a
high shift force to de-energize. Air passes over the poppet
through an annular section. This annular section means
sealing areas are of equal size, that forces created by air
pressure are equal in both directions, and the valve is
balanced. As a result the high shifting forces are
unaffected by changing air pressure on the ports.
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the Mac poppet valve the solenoid stroke is longer than the
valve stroke, offering wear compensation and continued
operation. The solenoid design means that regardless of the
position of the valve, the solenoid can close, virtually
eliminating coil burnout an AC applications. |
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Seals
are utilized at each end of the Mac poppet with a unique
section, these promote a wiping action within the valve,
keeping friction low and ensuring that shifting forces are
virtually unaffected by typically contaminated air.
The
valve design allows for constant high flow, maintained
throughout the pressure range, and a full flow exhaust. With
universal porting available, there are six functions
available in one valve.
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Small
4 Way Valve
The
4 way direct solenoid poppet valve also adopts the Mac
solenoid design, and shares all the features of the three
way poppet valve. Internally there are effectively four
balanced poppets on a one-piece valve stem.
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The
exhaust seals are not under inlet pressure, thus
reducing friction. When the valve shifts, the end
poppets seal first on conical seats cushioning the
inlet poppet, and eliminating cutting. With direct
action, high shifting forces, and minimized friction
the valve offers a fast response and high flow in a
small package. These features of the 4 way
individual valve, are also used as a solenoid air
pilot for some of the larger spool valves from Mac. |
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Large
4 way Spool valves
Within
a valve, a high shifting force in both directions results in
high reliability. Spool valves use an air pilot valve as a
drive force, and an air/spring return as a return mechanism.
The unique patented MAC solenoid provides a powerful drive
force, which in turn allows for a stronger return force to
be used. When big surface areas are used on both ends of a
main valve spool, reliability can be improved even more.
The
Mac patented spool and bore combination ensures low
friction. Chemically hardened bonded seals eliminate valve
creep. Precision ground, bonded spools control compression
leading to optimum sealing and minimum friction. Lubricant
within the rubber compound enhances non-lube service.
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Large
3 way valves
The
larger 3 way valves are solenoid pilot, or air pilot
operated. They use the same precision ground, bonded spools
found in the other Mac valves. The Mac design incorporates a
checked air accumulator, which feeds the air spring and
pilot. The check valve protects the accumulator from inlet
pressure fluctuations.
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The
accumulator stores several times the volume of air required
to shift the valve, and bleeds to atmosphere when the inlet
pressure is removed. A spring return provides consistent
shifting force at low pressures and a memory. |
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