1 RG 70 en
3
1
GENERAL
1.1
Scope of the manual
This manual provides essential information on series ZX
rotary globe valves. Actuators and positioners are only dis-
cussed briefly. Refer to the individual manuals for further
information on their installation, operation and mainte-
nance.
1.2
Valve construction
Series ZX valves are flanged rotary control valves. The valve
cage and plug with stem is a module accessible through
the bonnet opening of the body. Fluid flows up into the
cage sealed between the body and the bonnet. The plug
rotates inside the cage and seals against the cage when
closed, without any additional parts. The flow opening of
the cage and the V-shaped plug form the desired character-
istic curve of the valve when operated at 0 to 100 %. Valve
closes clockwise.
The axial bearing of the stem is located outside the valve
body in the yoke of the bonnet. The bearing support pre-
vents the stem from ejecting through the pressure bound-
ary of the valve under pressure in the event of a structural
failure of the stem-to-closure member.
The detailed structure is revealed by the type code shown
on the valve identification plate. The type code is explained
in Section 11.
1.3
Valve markings
The body markings are: manufacturer's trademark, nominal
size, pressure rating and material of the body. The valve has
an identification plate attached to it, see Fig. 2.
Markings on the identification plate:
1.
Body and bonnet material
2.
Trim material (plug)
3.
Seat material (cage)
4.
Maximum operating temperature
5.
Minimum operating temperature
6.
Maximum shut-off pressure differential
7.
Type designation
8.
Valve manufacturing parts list number
1.4
Technical specifications
Face-to-face length: ANSI/ISA-75.08.01,
ANSI/ISA-75.08.06 (Long)
Body rating:
Class 150 to Class 1500
PN 10 to PN 100
Max. pressure differential:
acc. to pressure class
Temperature range: -80° to +425 °C
Flow direction:
indicated by an arrow on the body
Actuator mounting: ISO 5211 mounting interface
Shaft connection:
drive by key
Dimensions:
see Section 10
Weights:
see Section 10
Note that the max. shut-off pressure is based on the
mechanical maximum differential pressure at ambient tem-
perature. You must always observe the fluid temperature
when deciding on applicable pressure values. When select-
ing a valve you must also check the noise level, cavitation
intensity, flow velocity, actuator load factor, etc. using Nel-
prof.
NOTE:
Selection and use of the valve in a specific application
requires close consideration of detailed aspects. Due to
the nature of the product, this manual cannot cover all the
individual situations that may occur when the valve is
used.
If you are uncertain about use of the valve or its suitability
for your intended purpose, please contact Metso for more
information.
For valves in oxygen service, please see also the separate
installation, maintenance and operating instructions for
oxygen service (see Metso document id:10O270EN.pdf )
Fig. 1
Construction of a Neles RotaryGlobe
Fig. 2
Identification plate example
ATTENTION:
TYPE
BODY
No.
SEAT
TRIM
max
ps
min
INSTALLATION OR SERVICING.
t
t
READ INSTRUCTIONS BEFORE
MADE BY
METSO AUTOMATION
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(4) (5) (6)
(3) (8)
(7)
