YAMADA NDP-40 series, Maintenance Manual

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▪ Remove the center disk from one side using the PP wrench
(special tool: Part No. 771868). [Fig.5.6]
▪ After the center disk (outside) has been removed, remove the
diaphragm and the center disk (inside).
Remove the center disk and center rod from the opposite side
of the main body.
▪ Fix a double nut to one end of the center rod and take the
diaphragm and center disk off the opposite end. [Fig.5.9]
Be careful not to scratch or score the center rod.
5.2 Inspection
▪ Diaphragm
If the diaphragm is worn out or damaged, replace it.
New replace just one diaphragm.
Guideline of diaphragm life
CR, NBR, EPDM 10,000,000 cycle
FKM 2,500,000 cycle
PTFE 3,000,000 cycle
TPEE, TPO 15,000,000 cycle
(When used with clean water at room temperature)
▪ Center rod [Fig.5.8]
Measure the diameter, and if it is outside the usable range,
replace the rod.
Usable range of center rod
ø0.9815 ~ ø0.9843 in {ø24.93 ~ ø25.00 mm}
5.3 Installation
■
B_C, B_N, B_E, B_V, B_H, B_S types
For installation, see [Exploded View] on the separate sheet and install in the reverse order of disassembly.
▪ Apply assembly grease to the center rod, and insert it into the
main body.
▪ Insert the cushion (except with the NDP-80). (cf. Fig.5.9)
▪ Keep the marking “OUTSIDE” to liquid end for CR, NBR, EPDM,
FKM diaphragms. Keep the convex side to the outside for TPEE,
TPO diaphragms.
▪ Tighten the center disk using the PP wrench (special tool: Part
No.771868) for the BP_, BV_ types. Apply proper Thread locker
to the thread of center disk.
(No coned disk springs and nuts are needed.)
Tightening torque for center rod
BA_, BS_, BF_ 43 ft-Ibf {60 N-m}
BP_, BV_ 36 ft-Ibf {50 N-m}