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Technical description
Each Camcon actuator or valve
design is based on the same fundamental concept which uses
a low impedance coil to momentarily change the spatial distribution
of magnetic flux generated by a high-power permanent magnet
or magnets. As a result a spring-loaded armature is catapulted
from one stable position to the opposite stable position.
Only a very short pulse of
electric current is needed to change the armature position
and there is no current needed to maintain either stable
position. By clearing or obstructing an orifice, the movement
of the armature permits or prevents passage of a fluid (gas
or liquid). Because the operation is bi-stable, only on/off
status being permitted by nature of the concept, precise
and programmable digital control can be applied.
By this means great precision
of delivery is obtainable. Because the action is so rapid,
the flow of a fluid or gas can be controlled with much faster
response times, or its flow can be modulated with much higher
frequency, than with any other known valve.
All the valves operate through
having non-linear magnetic field gradients with high-density
regions either round two air gaps or round two pole-pieces.
The magnetic fields are generated by high-power high-density
permanent magnets. A magnetisable non-polarised armature,
or part of such an armature, is able to move to and remain
in either of the two magnetic high-density regions. The
high magnetic force locks the armature stably in each location.
In most valve drivers the
armature is fitted resiliently by means of a spring or springs,
exerting a force lower than that of the magnetic force,
away from the pole positions and towards the central position
between them. The armature therefore still remains stably
in its selected pole position.
The armature can move under
one of two conditions:
| (a)
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When
current is applied to an electro-magnet modifying the
magnetic gradient, to the extent that the spring force
overcomes the local magnetic force; or |
| (b) |
The
magnetic circuit is modified, reducing local magnetic
flux. |
In each case, magnetic flux
is reduced at one air gap or pole-piece, while being momentarily
increased at the other. The result is translation of the
armature to its alternative stable position.
The electric current is supplied
as a high-energy short duration pulse, providing momentary
magnetic flux change. Particularly in the versions with
spring loading, the result is high-speed translation of
the armature to its opposite location.
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