EXPANSION VESSELS FOR SOLAR ENERGY
Preload expansion vessels with replaceable membrane for installation of solar energy
Tanks made of welded steel made from two bottoms and curved metal sheet ring connected to each other through welding cords, made following the procedures and with homologated staff according to the European Directory 97/23/CE for Pressure Units.
All the expansion vessels of our DP/VS and DP/VSV types are manufactured, tested, checked and certified by our company.
APPLICATION:
Expansion vessels type DP/VS and DP/VSV are designed for installations of solar energy and guarantee the safety operation of the solar vessel during / or after the watertightness of the tank.
The solar collectors can reach high temperatures. Due to this, the evaporation of the solar liquid can happen, with the possibility of producing extreme high temperatures in the circuit, causing damages in the components. For this reason, the expansion vessels are equipped with a specially membrane resistant to 140 ºC temperature.
In contrast to the expansion vessels for heating, the solar expansion vessels, apart from adjusting the volume expansion of the heat conducting fluid, they are useful for equalizing the volume reduction in case of cooling.
OPERATION
There is a full air chamber under pressure between the membrane and the tank plate. Once connected the expansion vessel to the circuit to which is intended, the temperature rises and, whit it, also the volume of water (see image 1)
When the membrane is filled with water, the air is pushed and it is compressed. The water volume keeps expanding until the maximum working temperature water is reached. At this state, the membrane occupies almost all the space of the tank (see image 2)
Once the effort stops, the temperature of the installation goes dawn gradually and also the water volume. The water starts to come out of the tank due to the pressure of the air found in the pressurized chamber. The air pushes the membrane till it gets the original pressure back. Finally, when the vessel reaches its initial position, a new cycle begins (see image 3)
At the moment of setting up the vessel in a solar installation, the following points must be borne in mind:
· Before proceeding to the installation, make sure that the expansion vessel volume has been calculated by the authorized staff.
· The expansion vessel must be placed in the return piping of the solar installation, as far as possible from the solar collector.
· The expansion vessel will be installed in such way that airbeds cannot be produced.
· Avoid radiations near the expansion vessel to protect membrane against the possible rises in temperature.
· No allow any valve that could be closed and insulate the own circuit of the expansion vessel.
· Fit the inflating pressure of the vessel to the network pressure.(P inflating= P network + 0,2 bar).
MAINTENANCE
-The maintenance must be done exclusively by authorized staff.
- At least once every six months, check through the inflating valve that the air chamber pressure is maintained in the correct values. Be careful of checking the contrast of values at the same temperature.
- Never disassemble the expansion vessel without having depressurized the installation previously.
- The standard pressure of the vessel must be regulated and fitted according to the function of the installation in which the vessel is installed
- Protect the expansion vessel from the inclemency of the weather.
TECNICHAL DATA
- Replaceable EPDM membrane.
- Working conditions: -10 ºC to 100 ºC
- CE marked according to Directory PED 97/23/CE.
- Galvanized steel flange with inner protection of polypropylene in the contact zone with the water.
- Water/ Glycol mixture to 50%.
- External finish colour white RAL 9010
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