IM-P537-01
EMM Issue 1
25
Pressurised Thermophysical deaerator with operator manual for the control unit
3.3.4 Safety valves connection.
Spirax Sarco integrated systems are equipped with one or more safety valves. On the primary side, it is
assumed that the safety valve is installed on the deaerator.
The connection of the safety valve to a suitable vent and discharge system serves both to prevent damage
to the device and to reduce the risk of accidents that may be caused by water. All vents and pipes connected
to the safety valve must comply with the regulations in force.
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Do not install a valve between the safety valve and the vent or vent line. This could cause serious
damage if the safety valve trips and the manual valve is closed. This situation can cause an excessive
increase in pressure in the circuit, which may explode.
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The size of the vent lines of the safety valves must be sufficient and suitable to the operating conditions
on site. Maximum back pressure and temperature must be taken into account.
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The safety valves must be installed in such a way that no excessive static or thermal stress is
transmitted to the valve from the discharge and drain lines (take into account any reaction forces
generated during discharge).
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The discharge lines must be laid in such a way as to facilitate the flow.
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The discharge line of the safety valves must be laid in such a way as to ensure a slope up to the drain
hole drilled at the lowest point of the pipe (the size of the drainage hole must be adequate).
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Draining of the discharge line is absolutely necessary in order to prevent the formation of a water
head that generates back pressure on the safety valve discharge line.
3.3.5 Draining the generator
PDA deaerators are equipped with discharge/drainage with manual valve installed at the bottom of the tank.
This valve discharges at the same pressure and operating temperature as the deaerator and it can cause
serious physical injury or even death if not properly connected. It is therefore recommended to connect the
drainage of the deaerator to the system's discharge network in accordance with the regulations in force.
3.3.6 Other bleeds/vents/drainages (where applicable)
PDA units can be equipped with optional systems such as primary steam line drainage system.
The drainage of the primary steam line can be directed/transferred into the condensate return line of the plant.
3.4 Pneumatic section connection
The Spirax Sarco integrated systems are equipped with pneumatic control valves requiring compressed
air with calibration ranging from 15 to 100 psi, and on/off valves requiring compressed air with calibration
ranges specified in the drawings provided and installation manuals for the specific component. The pneumatic
actuators require an air supply pressure of 15 to 100 psi. A reducer filter with pressure gauge is installed
on each valve to regulate the supply pressure at the valves. To avoid damaging the pneumatic actuators
membrane, it is necessary to check the supply pressure required by each valve.
The procedure for calibration of the reducer filters RF is explained in the user and instruction manual included
in the technical file of the project provided with the unit.
For questions not answered in this manual, or if the procedures described are not clearly understood, please
contact Spirax Sarco for clarification.
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Ensure that the instrument air supply line has been closed and that the downstream line is not under
pressure before starting any connection.
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Note: For all pneumatic connections, the use and/or type of sealant or couplings gaskets must be chosen
according to rules accepted by common practice, or according to the installer's specifications.
