YAMADA DP-20F/P, Maintenance Manual

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3
Fig.3.8
Fig.3.9
Fig.3.10
3.2 Inspection
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Ball valve type
▪ Ball [Fig.3.6]
Measure the diameter, and if it is not within the
permissible range, replace the ball.
Permissible range of ball diameter
DP-20F/P SØ 24.3 - SØ 27.8 mm
DP-25F/P, DP-25F/C
DP-38F/P, DP-38F/C
SØ 31.5 - SØ 36.0 mm
▪ Valve seat [Fig.3.7]
Measure the dimension shown at left, and if it is not within
the permissible range, replace the valve seat.
Permissible range of valve seat dimension
DP-20F/P
2.8 - 7.0 mm
DP-25F/P, DP-25F/C
DP-38F/P, DP-38F/C
3.2 - 7.5 mm
■
Flat valve type
▪ Flat valve [Fig.3.8]
Measure the dimension shown at left, and if it is not within
the permissible range, replace the flat valve. If the flat
valve is worn out or cracked, replace it, too.
▪ Valve seat [Fig.3.9]
Measure the dimension shown at left, and if it is not within
the permissible range, replace the valve seat.
Permissible range of valve seat dimension
9.6 - 12.2 mm
3.3 Installation
For installation, see [Exploded View] on the separate sheet and install in the reverse order of disassembly.
Tightening torque for vertical tie rods
DP-20F/P 5 N•m
DP-25F/P, DP-25F/C 7 N•m
DP-38F/P, DP-38F/C 15 N•m
<NOTE>
▪ Make sure the sealing surface is not dirty or damaged.
▪ Replace the PTFE O rings regardless of its condition.
▪ Make sure that the directions of each coned disk spring
are correct. [Fig.3.10, Fig.3.11]
▪ Retighten the tie rods before starting the pump.
(See [7. Retightening of tie rods])
Permissible range of flat valve dimension
5.6 - 7.2 mm
Fig.3.7
Fig.3.6
Fig.3.11
DP-20F/P, DP-25F/P