Cashco DA6 - Manual (Page 9)

IOM-DA6 9
While re strain ing valve plug (20) from
ro tat ing by torque wrench on upper end
3/4" hex, use another wrench to tighten
diaphragm locknut (7) to a torque of 180-
200 ft-lbs.
16. This completes assembly of ITA; remove from
vise.
F. Main Reassembly:
1. Place body (23) in a vise.
2. Reinstall internal sensing drilled plug (32) with
compatible thread sealant.
3. Fit the o-ring cage seal (15) into its body (23)
groove.
4. For metal diaphragm construction, place
seal ant (“Gasoila” or equal) on both sides of
diaphragm gasket (37) and position on body
(23) diaphragm fl ange.
5. Position properly oriented lower cage gasket
(21) onto lower shelf of cage (19).
6. Insert cage (19) into body (23) recess. Prop-
er ly align all cage bolt (18) holes as there is
only one cir cum fer en tial location pos si ble for
this align ment. Engage all of the cage bolts
(18), then evenly screw in the cage bolts in
one-half revolution increments, taking care
NOT TO “COCK” THE CAGE (19) IN THE
BODY. Torque the cage bolts (18) to 13-15
ft-lbs.
7. Dynamic Side Seals:
a. Type CP: Position the ITA's valve plug
(20) lower end over and into upper end
of cage (19) until the cap seal (27.1)
edge touch es the upper lip of the cage
(19). While gently ap ply ing force to press
the valve plug (20) into the cage (19), si-
mul ta neous ly use hand thumbs to light ly
press the cap seal (27.1) inwards into
the groove of the valve plug (20) until the
cap seal (27.1) “slips into” the cage (19).
DO NOT USE TOOLS, LU BRI CANT, OR
HEAVY FORCE TO ENGAGE THE CAP
SEAL (27.1) INTO THE CAGE (19). Do
not press inwards on the cap seal (27.1)
too much or the cap seal (27.1) may slide
out of its groove.
b. Type PR: Position the ITA's valve plug
(20) lower end over and into upper end
of cage (19) until the lower piston ring
seal (27.5) touches the upper lip of the
cage (19). While gently applying force to
press the valve plug (20) into the cage
(19), simultaneously use fi ngers to lightly
circumferentially press the fi rst (low er)
piston ring seal (27.5) inwards into the
valve plug (20) groove until the fi rst piston
ring seal (27.5) “slips into” the cage (19).
Repeat for the second piston ring seal
(27.5)
c. Type UC: Position the ITA's valve plug (20)
lower end over and into upper end of cage
(19) until the cap seal (27.1) edge touches
the upper lip of the cage (19). While gently
applying force to press the valve plug
(20) into the cage (19), si mul ta neous ly
use hand thumbs to light ly press the u-
cup seal (27.3) inwards into the groove
of the valve plug (20) until the u-cup seal
(27.3) “slips into” the cage (19). DO NOT
USE TOOLS, LU BRI CANT, OR HEAVY
FORCE TO ENGAGE THE U-CUP SEAL
(27.3) INTO THE CAGE.
d. Type NO: Position the ITA's valve plug
(20) lower end over and into the cage
(19), allowing plug (20) to enter fully.
8. For composition diaphragm construction,
align diaphragm (9) bolt holes with body (23)
di a phragm bolt holes.
9. Aligning matchmarks and bolt holes, place
cover dome (25) onto body (23) diaphragm
(9) fl ange.
10. Reinstall all fl ange bolts (11) and nuts (12)
with nameplate (99) located under one bolt
head. Hand-tighten nuts (12).
NOTE: If a six-ply diaphragm is being used,
it is important that the diaphragm (9) is “pre-
formed” – pulled together to remove as much
entrapped air as possible and allow formation
of a diaphragm (9) convolution. Starting with
the body bolts and nuts (11,12) hand tight ened,
“preforming” can be accomplished by any one
of the following techniques:
a. Apply 30-50 psig pressure to the valve
inlet and the valve outlet.
OR
b. Block the valve inlet and outlet and apply
30-50 psig under the di a phragm through
the 1/4" NPT (plugged) external pres-
sure sens ing connection on the valve
di a phragm fl ange.
AND
c. Leave pressure on through tightening
of bolt ing (11,12).