Technical Manual
MT 302-I
5
2.0
INSTALLATION
2.1
GENERAL WARNINGS
Before installation, commissioning or maintenance, operators must:
-
Take note of the safety regulations applicable to the
installation in which they must work;
-
Obtain the necessary permits to operate when required;
-
Acquire the necessary personal protective equipment
(helmet, goggles, etc.);
-
Ensure that the area in which they operate is equipped with
the required collective protection and the necessary safety
information.
The equipment and its components must be handled after ensuring
that the lifting means are adequate for the loads to be lifted (lifting
capacity and functionality). The equipment must be handled using the
lifting points provided on the equipment itself.
The use of motorized means is reserved for the persons in charge.
If the installation of the equipment or its accessories requires the
application of compression fittings, these must be installed following
the instructions of the manufacturer of the fittings themselves. The
choice of fittings must be compatible with the use specified for the
equipment and with the specifications of the system when provided for.
Commissioning must be carried out by properly trained personnel:
during commissioning activities, personnel who are not strictly
necessary must be kept at a distance and the forbidden area must be
suitably marked (signs, barriers, etc.).
2.2
GENERAL REQUIREMENTS
The valve must be installed in compliance with the regulations (laws or
standards) in force in the place of installation.
In particular, systems for natural gas must possess features in
accordance with the legal requirements or regulations in force at the
installation site or at least in accordance with EN 12186 or EN 12279
(please note that installation in compliance with these regulations
minimizes the risk of fire hazard).
The valve must be installed making sure that the operating pressure of
the unit on which it is installed never exceeds the maximum
permissible pressure value (PS).
The user must also set up the system with appropriate venting or
drainage systems in order to discharge the pressure and the fluid
contained in the system before carrying out any inspection and
maintenance activities.
The pilot of the valve is sealed after being tested and calibrated; the
sealing is done in three points:
On the adjustment plug
2.3
SPECIAL REQUIREMENTS
Before installing the valve, you must ensure that:
-
The valve can be inserted in the space provided and is
sufficiently accessible for subsequent maintenance
operations Table 2 shows the dimensions and weights;
-
In the case of installation with horizontal flow direction, the
upstream and downstream piping is at the same level as the
input and output connections;
-
The upstream piping (and downstream only if installed with
horizontal flow direction) can bear the weight of the valve;
-
The inlet / outlet flanges of the piping are parallel to the
valve sealing surfaces;
-
The inside of the valve is clean and the valve itself has not
been damaged during transport;
-
The upstream piping has been cleaned in order to expel
residual impurities such as welding slag, sand, paint
residues, water, etc ..;
Install the valve taking into consideration that the direction of flow is
required and is indicated with an arrow on the body of the valve itself.
The connections to the input and output pipes are done using standard
flanges whose sizes and types are indicated on the rating plate (see
section 2.4); the choices of connecting screws and seals must be
made by the installer considering this information and the conditions of
use at the installation site.
N.B The valve is designed to operate at atmospheric
backpressure (=0). Please pay attention in ensuring compliance with
the valve design conditions during the sizing of the line downstream of
the valve itself.
NOTE: the correct sizing of the discharge line downstream of the valve
is the responsibility of the system designer.
2.3
REACTION FORCES DUE TO
DISCHARGE
After opening of the valve due to overpressure of the control fluid,
reaction forces are generated due to the motion of the fluid. These
forces are then transmitted to the junctions and couplings in the valve
installation phase. The designer of the system is therefore responsible
to provide appropriate supports to correctly withstand the dynamic
forces generated.
When calculating the reaction forces with gas, refer to standard API
520-Part II (August 2003):