Air vent valves even for boilers

The boilers require the assembly of air vent valves in order to achieve maximum efficiency during their operation, since an abnormal accumulation of gas (released in the system and due to the heating of the fluid) could block the whole system. In fact, air is mainly a double problem: on the one hand there is the risk of corrosion of the elements of the plant and, therefore, the progressive loss of efficiency; on the other there is the problem of cavitation which can cause the deterioration of the system and its malfunction. For these reasons, the air vent valves for boilers are required and in the catalog there are several models, all with automatic operation. The choice of automatic valves makes it possible to deal with the problems mentioned in completely autonomous way, without resorting to periodic intervention.

Air vent valves for boilers are simple devices and consist of some fundamental elements for optimal operation:
- The float: element that moves in relation to the filling of the valve chamber with air or water. It rises when the water fills the chamber and goes down when the air bubbles gather, forming macro-bubbles.
- The rod of the rocker arm: connecting element between the float and the shutter.
- The shutter: element placed at the top and necessary to close the air vent.
- The air vent: channel in which the air flows to be eliminated outside.

When the chamber fills with water the float rises and, through the rocker arm, the shutter closes the duct for the air vent. Once the air bubbles have gathered in the valve chamber, the float descends and causes the shutter to open.
Only at this moment the air can flow on the outside and the water pressure returns to rise, causing the ascent of the float and the beginning of the next cycle.

As previously stated, in the Gnali Bocia catalog there are several air vent valves for automatic boilers that derive from a controlled, guaranteed and ISO-9001 certified supply chain. The materials used are several:
- Brass EN 12165 - CW 617N: used for the valve body. It is a high workability alloy with a low lead content.
- Stainless steel: it is used for springs because it is resistant to the problem of corrosion.
- "Anti-sticking" synthetic rubber: it is an ideal polymeric material for sealing gaskets.
- Brass EN 12164 - CW 614N: material used for certain details and suitable for reducing heating and wear.
- Plastic materials: used for other details and they must be resistant to heat as they come into contact with high temperatures. Some examples can be Noryl and Hostaform.

As for the technical specifications, the air vent valves for Gnali Bocia boilers are designed to withstand temperatures of 100 ° C and pressures up to 10 bar.
 

Air is always present within the fluid circulating in a system in the form of dispersed micro bubbles. Sometimes, especially in the presence of controlled flow sections, these micro bubbles can coalesce, forming air bubbles of important dimensions that bring with them some problems of considerable importance:
- Corrosion: widely spread electrochemical phenomenon that leads, through different mechanisms, to the progressive deterioration of the structural integrity of the system or the boiler itself, compromising its use, especially in the long term;
- Erosion: mechanical phenomenon that develops, due to the impact of these air bubbles, against the walls of the pipes going, even in this case, to damage the system in a slow but constant way over time;
- Cavitation: thermodynamic phenomenon which, through a sudden reduction in pressure at the same temperature and vapor pressure, leads to the formation of more or less extended vapor zones within a fluid with consequent implosions that generate both damage to the structures involved and considerable acoustic phenomena.
In this context, the air vent valves are of particular importance as they allow the elimination of this and indirectly lead to longer life of the systems with benefits from both an economic and maintenance point of view. In fact, against a limited expense in the design and installation phase, it is possible to minimize extraordinary maintenance interventions to correct anomalies and malfunctions that are often difficult to identify and, depending on the location, can also be difficult to achieve.
Despite this, it is important to emphasize that proper installation and routine maintenance of the air vent valves is essential in order to take full advantage of the characteristics of these types of components. Conversely, neglect or carelessness in these stages can nullify the benefits of valves.
 

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