XLC 420
13
Interventions on the main XLC 400 valve
In case of malfunctioning or defects, that
can be found on the main valve, is possible to
intervene without removing the product
from the pipeline. The defects can be either
internal and external.
The
external defects
mainly concerns the
pilot circuit and are not related to the main
body of the XLC 400 control valve.
The
internal defects
concern the mobile
block, or the deterioration of the internal
components.
Problems can be summed up in three
categories:
a) the valve is blocked, the mobile block
does not move;
b) the mobile block moves but the valve
does not react because the diaphragm is
damaged.
c) the diaphragm is OK but the valve does
not close or leakages is reported.
The possible causes lead to:
defects on the diaphragm;
defects on the movements of the
mobile block;
friction caused by deposits and
corrosion;
problems on the gaskets;
defects on the sealing seat.
15
13
21
14
17
16
1
18
4
10
5
9
3
7
2
8
11
12
20
19
6
N.
Component
Material
1
2
3
4
5
6
7
8
9
Body
Cap
Position indicator
Pressure outlet tap
Upper flat o-ring
Obturator o-ring
Indicator stem
Main shaft
Guide ring
GJS 450-10 or GJS 500-7
10
Spring
11
Locking nut
12
Upper flat
13
Diaphragm
14
Obturator
15
16
17
18
19
20
21
Plane gasket
Gasket holder
Seat
Seat o-ring
Studs
Nuts
Washers
St. steel/Ni-plated brass
AISI 302
AISI 303/AISI 304/AISI 316
AISI 304/AISI 316
AISI 304/AISI 316
GJS 450-10 or GJS 500-7
AISI 316
NBR/EPDM/Viton
NBR/EPDM/Viton
AISI 303
AISI 303/AISI 316
Bronze/AISI 303/AISI 316
AISI 303/AISI 316
Painted st./AISI 304/316
Neoprene-nylon
St. st./paint. st./GJS 450-10/500-7
NBR
AISI 303/AISI 316
NBR/EPDM/Viton
AISI 304/AISI 316
