Cirrus SR22 Pilot Operating Handbook page 379

Cirrus Design Section 9
SR22 / SR22T Supplements
• A cabin floor-forward proportioning unit distributes fluid to the
propeller slinger ring assembly.
In addition to distributing fluid to the porous panels and propeller
slinger ring, the proportioning units provide an additional, distinct
pressure drop to the supply lines such that a specific flow rate is
provided to each protected surface. Small, flap-type check valves
positioned on the outlet of each proportioning unit port prevent the
back-flow of fluid from the associated panel
Porous Panels
The proportioned fluid enters the leading edge panels through the inlet
fitting(s) on the inboard end of the wing panels, and outboard end of
the horizontal panels. The outer surface of the panels is perforated
with very small openings to distribute the deicing fluid along their
entire length. The panels contain a porous membrane whose pores
are nearly 100 times smaller than the openings of the outer surface.
The leading edge panel serves as a reservoir as fluid entering the
panel fills the cavity behind the porous membrane then overcomes this
resistance to be distributed by the openings in the external surface.
Each panel incorporates a vent opposite the inlet which provides a
relatively large opening to release air from within the panel. A check
valve prevents air from entering the panel through the vent which
slows the "leak-down" of the panel during periods of inactivity.
Propeller Slinger Ring
Deicing fluid protects the propeller by a slinger ring mounted to the
spinner backing plate where the fluid is distributed by centrifugal
action onto grooved rubber boots fitted to the root end of the propeller
blades.
System Control
System operation is controlled by, Serials 22-0334 thru 22-0434; a
three-position switch mounted on the center console panel which
allows the user to select OFF, NORMAL, or MAXIMUM positions.
Serials 22-0435 & subs; two switches located on the bolster panel.
The first switch controls system operation through ON and OFF
positions, the second switch controls the system mode (flow rate)
through NORMAL and HIGH positions.
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Revision 09: 12-17-10