Home » Against the danger of legionella, a valve that recirculates water in expansion tanks
Expansion tanks are a very important element in hydraulic circuits.
Among other things, they act as a shock absorber against dangerous water hammer. Expansion tanks can also absorb pressure peaks by way of a membrane, and so protect the circuit.
The water invades the membrane, inflating it as the pressure increases. Vice versa, when the pressure drops the water is returned slowly to the hydraulic circuit together with the previously accumulated energy.
Even if the expansion tank works optimally and has a high discharge capacity, standing water forms inside it naturally; this type of water can be dangerous to health.
Standing water favours the proliferation of different types of bacteria, among which Legionella pneumophila, which is particularly hazardous because it causes a dangerous form of pneumonia.
To prevent the growth and spreading of this bacterium in water systems, and in doing so prevent the risk of legionella, guaranteeing constant water recirculation is fundamental, above all in the case of drinkable water and domestic hot water. Good practice, not just in public structures but also in homes.
The risk represented by expansion tanks is recognised by the “European Technical Guidelines for the Prevention, Control and Investigation of Infections caused by Legionella species”. It is precisely these guidelines that recommend using accessories that can stimulate the flow inside expansion tanks.
Our experience in designing and producing valves and hydraulic accessories has guided us in the selection of a particularly effective product for recirculating water. To complete the offer to our clients, we have added the system made by Globalwater solution ltd, a leading sector company, to our catalogue. The recirculation shut-off valve is called Flow-Thru and Mondeo has the exclusive for its distribution in Italy.
The Flow-Thru valve, connected to the expansion tank, was designed to constantly extract a part of the water that flows in the piping and push it internally so as to eliminate the risk of standing water. Contemporaneously, the design of the recirculation valve guarantees maximum circulation in the vessel and minimum drops in pressure in the main piping. The self-directing design also eliminates the risk of leaks or connections that are too tight.
The system has a shut-off ball valve which blocks the water flow and, as a result, makes intervening on the vessel for maintenance or replacement very easy.
The presence of a built-in discharge valve instead makes it possible to sample the water without having to interrupt the main flow.
The valve has WRAS and ACS certification, which guarantee the highest standards when dealing with products and materials that come into contact with drinkable water.