16
Dival SQD-1 - MT 234-E - 02-2020
EN
INSTALLATION
Apparatus Specification plates:
Fig. 11
The list of symbols used and their meanings are listed below:
Pumax= maximum operating pressure at the inlet of the apparatus.
bpu=
range of variability of the inlet pressure of the pressure regulator in normal operating conditions.
PS=
maximum pressure for which the body and its inner metallic partition walls are designed in accordance with
the strength requirements in this document.
Wds
=
setting range of the pressure regulator which can be obtain using the parts and the setting spring fitted at
the moment of testing (that is without changing any components of the apparatus.
Wd
=
setting range of the pressure regulator which can be obtain using the parts and the setting spring fitted at
the moment of testing
Cg
e
KG = experimental coefficient of critical flow.
AC=
regulation class
SG=
closing pressure class.
AG=
intervention accuracy
Wdso= range of intervention for the over pressure of slam-shut which can be obtain using the setting spring fitted
at the moment of testing.
Wdo=
range of intervention for the over pressure of slam-shut which can be obtain using the setting springs indi
-
cated in the tables.
Wdsu= range of intervention for pressure decrease of slam-shut which can be obtain using the setting spring fitted
at the moment of testing.
Wdu=
range of intervention for pressure decrease of slam-shut which can be obtain using the setting springs indi
-
cated in the tables.
5.2
GAS INPUT, CONTROL OF EXTERNAL TIGHTNESS AND SETTING
The pressurization of the equipment shall be performed very slowly. Should not any stabilization procedure be carried
out, it is recommended to keep gas speed in the feeding piping at a value equal to 5 m/sec during pressurization.
To protect the apparatus from damage, the following operations must never be carried out:
•
Pressurization through a valve located downstream from the apparatus itself.
•
Depressurization through a valve located upstream from the apparatus itself.
External tightness is guaranteed if no bubbles form when a foam medium is applied on the element under pressure.
The regulator and any other apparatuses (slam-shut, monitor) are normally supplied already set for the desired set-
point. It is possible for various reasons (e.g., vibration during transport) for the settings to be changed while remaining
within the values permitted by the springs used.
We therefore recommend checking the settings using the procedures illustrated below.
In installation consisting of two lines, we suggest commissioning one line at a time, starting from the one with the
lover set-point, known as the “reserve” line. The set-point of the apparatuses in the line will obviously deviate from
those specified in the table 4.
