Cashco 1000 LP - Manual (Page 7)

IOM-1000LP-Basic 7
c. Flow induced wear at expansion zone
where fl uid turns to enter the piston (24)
center.
d. Where the piston (24) ribbed guides
bear (guide zone).
If wear is signifi cant at any of these points,
both cylinder sub-assembly (21) and piston
sub-assembly (24 or 24, 25 and 26) should
be replaced. (Cashco, Inc., does not rec om -
mend attempting to replace the valve seat
(21.2) by pressing out and then re-pressing
in. Cashco, Inc., also recom mends that a
cyl in der (21) and piston (24 or 24, 25 and
26) be replaced as a set. Composition seat
discs (25) may be re placed individually.)
5. If a composition (soft) seat trim design is
uti lized, use the following sub-steps:
a. Tighten the “fl ats” of the seat disc screw
(26) within a vise. Firmly hand-grip the
piston (24) and turn CCW to loosen the
seat disc screw (26). If too tight, place a
screwdriver or similar rod within the pis-
ton (24) port holes and rotate. Re move
the piston (24), and inspect for raised
burrs around the port holes if a device
is used to loosen; deburr as re quired.
NOTE: Do not grip the piston (24) with
a wrench.
b. Remove the seat disc (25) and clean
the re cessed piston (24) area where the
seat disc (25) is placed. If the edges
which form the recess of the piston (24)
are worn, also replace piston (24) and
seat disc screw (26).
c. Place seat disc (25) into recessed end
of piston (24).
d. Place thread sealant on threaded por-
tion of seat disc screw (26), and manu-
ally ro tate piston (24) into seat disc
screw (26) (still fi xed in vise) to secure
seat disc (25). Tight en seat disc screw
(26) fi rmly. Do not over-tighten to the
point of em bed ding the seat disc screw
(26) into the seat disc (25); the seat disc
(25) should lay fl at with no rounded sur-
face. A mech anical aid is nor mal ly not
required; hand-tightening is nor mal ly
suf fi cient.
6. If utilized, place piston spring (30) over
small er end of cylinder (21).
7. Insert piston assembly (24 metal seat; 24,
25 and 26 comp. seat) into end of cylinder
(21).
8. Place piston collar (23) over end of piston
(24), ensuring that the spherical surface of
the piston (24) and the piston collar (23) bear
against each other.
9. Clean the body (1) cavity thru the openings.
Clean the “jet area” just inside the body (1)
outlet end thru which the piston (24) proj-
ects. Clean all parts to be reused. NOTE:
On valves originally sup plied with Option
1000-55, “ox y gen clean”, main te nance
must in clude a level of clean li ness equal to
Cashco, Inc's., cleaning standard #S-1134.
Contact factory for details.
10. Use special care cleaning the fl at mating
sur fac es of the body (1) and cylinder (21)
shoulder, as this pressurized joint is metal-
to-metal with no gasket.
11. Lubricate the cylinder (21) threads lightly
with thread sealant. Insert the entire trim
stack into the body (1) opening and thread
until tightly seated. NOTE: Take special
pre cau tion to keep piston collar from getting
“cocked” at an angle when inserted. Impact
until the cylinder (21) shoulder is metal-to-
metal with the body (1).
12. Inspect the body (1) outlet end to ensure that
the piston (24) is concentric to the body (1)
bore in the jet area and has clearance on
all sides. Under no conditions should the
piston (24) be touch ing the body (1). Use
two pencils or similar shafts to place in inlet
and outlet ends of valve and alternately push
on each end of the piston (24) to ensure
free movement. NOTE: Total move ment is
ap prox i mate ly 1/8" (3.2 mm).
13. Bench test unit for suitable operation and
seat leakage. NOTE: Regulators are not
nor mal ly tight shutoff devices. Pressure
must build above setpoint for best shutoff.
14. Spray liquid leak detector around cyl in der
(21)-to-body (1) connection and check for
leak age. Test pres sure should be a min-
i mum of 100 psig (6.9 Barg) at the inlet, or
actual service con di tions if high er.
Cylinder Sub-Assembly (21) with Piston (24) Metal
Seat Construction
Jet Zone (E.10)
(21.2) Pressed In Seat Ring (E.5 b)
4
Guide Zone (E.5 d)
1
21.1
Expansion Zone (E.15 c)