Wherever water, chemical mixtures, oil and gases are transported through pipes, solenoid valves are instrumental in remotely or automatically controlling the flow and transfer of fluids. But when fluid control handling equipment needs to be installed in harsh outdoor environments, making the correct choice of components becomes essential to ensure safety, reliability and the long life of the entire system.
Risks of outdoor operation
Where solenoid valves are used in outdoor installations, they are exposed to harsh conditions, such as direct sunlight, extreme heat, sub-zero temperatures, moisture, chemicals, dirt and dust. This can be tough on both electrical parts and the valve materials, increasing the risk of corrosion and oxidation. The electrical copper coil in a solenoid valve is also vulnerable; if damaged, it can generate heat or sparks, which in turn may create an explosion if the valve is employed to control the flow of a flammable gas or liquid.
Legislation is evolving to require the use of safer and more durable materials, prompting a rise in demand for products made from stainless steel, which is the most cost-effective material offering durability and resistance to corrosion.
Security is also an important consideration in some applications, as exposed valves can be tampered with or otherwise damaged.
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Choosing the right valve
In these tough outdoor environments, what particular features should be looked for when selecting a solenoid valve? For the most demanding applications, it is a pre-requisite that the body of the valve should be made from a corrosion resistant material, and the electrical coil and plug system should not only be waterproof and dust-proof, but should preferably also be approved for ATEX zones to minimise the risk of explosions.
One alternative solution to investing in better-grade materials could be the option of installing the valve within an outdoor cabinet. However, such cabinets, which need to be waterproof, insulated, fire-resistant and secure are often more expensive, take up a lot of space and are difficult to source and install.
One example of the type of products now available to address the stringent requirements typical in outdoor use scenarios is the 221G solenoid valve in stainless steel. It has a large flow valve for pressures ranging from 0 to 16 bar giving versatility to a wide range of tasks and can be used for dry or lubricated air, neutral gases and liquids. It is able to withstand corrosion, oxidation and aggressive chemicals.
And be sure to check the seal. Sealing is a potential weak point in any fluid handling application and the use of fluroelastomer sealing is a further important feature of solenoid valves used outdoors. Some other elastomers may swell or degrade when exposed to chemicals so correct seal material specification is critical.
Article contributed by Valéry Blanchet, Marketing Product Manager, Fluid Control Division Europe, Parker Hannifin Corporation.