Butterfly Valve Disassembly And Reassembly - Cessna 188 Series Service Manual

MODEL 188 & T188 SERIES SERVICE MANUAL
19-82.
DESCRIPTION. An electric three-way spray
SHIM CHART
valve assembly is available for mounting between the
pump. the hopper and the nozzles.
The valve is con- SIZE
PART NO.
THICKNESS
trolled by a flexible shaft and a knob in the cockpit.
This valve permits a bypass for pressure control and LARGE 1608075-1
005
also provides recirculation through the hopper for a SMALL 1608075-3
005
more consistent mixture of the spray material
Also LARGE 1608075-2 014
incorporated into the control valve is a bleed-back SMALL 1608075-4
014
valve to relieve boom pressure after the control
valve is closed to prevent nozzle "drip".
19-83. REMOVAL AND INSTALLATION.
NOTE
NOTE
The instructions outlined in paragraph 19-86
should be followed if Single-Engine Service
If the adjustment screw is not disturbed.
Letters SE78-31 and/or SE78-59 have not
suction adjustment should not be required.
been complied with. To comply with these
Service Letters, refer to paragraphs 19-87
a. Completely drain hopper.
and 19-88
b. Disconnect plugs at motor, remove sta-strap
and remove wiring.
19-86.
BUTTERFLY VALVE DISASSEMBLY AND
c.
Disconnect hose coupler at forward end of valve.
REASSEMBLY. (See figure 19-29.)
d.
Remove hose and clamps at aft end of valve.
e.
Remove bolts attaching valve to adaptor at gate-
NOTE
box and remove gasket or seal.
f.
Reverse preceding steps for valve installation.
The manual and the electric valves contain
identical parts.
Therefore, the following
19-84.
DISASSEMBLY.
(BALL TYPE VALVES)
procedures apply to both valves.
(See figure 19-28 for valve disassembly).
a. Remove bolts and washers from coupler adapter
NOTE
(2) and hose adapter (15).
b.
Remove coupler adapter (2), O-ring packings (3)
If adjustment screw (21) is not disturbed,
and (5), and shims (4).
suction adjustment should not be required. c.
Remove hose adapter (15), O-ring packings (3)
and (15), and shims (4).
19-85.
ASSEMBLY.
(BALL TYPE VALVES)
(See figure 19-28.)
CAUTION
a.
Install ball (6). packing (20). support assembly
(8) with packing (19). valve control support (10) and
Do not intermix total shim thickness from
worm gear (9).
end-to-end.
Insert must be centered to
b.
Check ball (6) and seals (3), (24) and (26) fit as operate freely.
follows:
1.
Install adaptor (1), seal (3), adaptor (22) d.
Remove seal-attaching screws (14), existing seal
and seal (24) less packings, bolts and washers.
(13), and retainer (12).
If existing seal does not meet
2.
Applying equal forces against adaptors (1)
inspection criterion, or is questionable, discard old
and (22), measuring gaps between adaptors (1) and
seals and install new seals (13).
This will comply
(22) and valve body (5).
with Single-Engine Service Letter SE78-31.
3.
Install shims (4) and (25) as required to a
thickness of . 002-inch less than each gap measure-
NOTE
ment.
4.
Install side cover (29) and seal (26).
If seals are replaced per Service Letter,
5. During assembly, for measuring gap between
follow instructions outlined in the Service
valve body and two adapters, set valve assembly up- Letter.
If seals are not replaced, proceed
right, with hose adapter down on flat surface and as follows.
cam-lock adapter up.
Place a 5 or 6 pound weight on
top to give "equal forces" for seal-to -ball seating.
e.
Check to see that butterfly halves (11), seals (13),
then measure gap.
shaft (8) and seal retainer screws are sealed (Loctite
6.
Install shims (27) as required to a thickness
Sealant P/N 59231. ) To ensure proper sealing, close
of approximately .002-inch less than the gap measure-
butterfly valve until seat is contacted.
Tighten screws
ment.
(14) 1/4 to 1/2 turn after seating to prevent deforming
c.
Disassemble components and install packings (2). seals.
(23) and (28).
d.
Assemble all components and install attaching
NOTE
bolts and washers.
The following procedure must be followed
in assembling the spray valve.
19-61