Solenoid control without the bang
Paul Hobden looks at the challenges surrounding process control in potentially explosive atmospheres and how they can be overcome.
Process control achieved using innovative design and industry expertise can deliver solutions to help improve process efficiency and productivity. Very often, at the heart of these systems is a humble solenoid valve.
These devices have evolved over the years to allow them to be used in many challenging applications.
The use of chemicals and high temperature steam are often controlled by solenoid valves so their design characteristics need to match the application. The latest plastics and polymers, for example, allows solenoid valves to conform to food and hygiene regulations.
Some applications involve potentially explosive atmospheres so equipment operating in this environment must have been certified to the appropriate ATEX ratings. The rather complex system for grading the working environment and matching the design of the components to ensure a safe application can be a daunting prospect. When creating a new, fully certified installation, it is important to select partners that understand process control design and which have the ability to deliver bespoke solutions that are certified to the standards in force locally. This will allow design features such as vibration-proof, bolted coil systems, and increased leak-tightness to be included in a system. Just because the application requires a component that is certified for operation in potentially explosive atmospheres, it shouldn’t mean that the choice of control valves is reduced.
As part of its development of ATEX and IEC-Ex certified versions of its components and systems Bürkert Fluid Control Systems has established a centre of competence in Menden, Germany. Testing of individual components and complete valves is a continuous process, partly to ensure continued compliance with a wide range of certifications, but also to ensure that quality standards are being maintained.
In situations where an existing component will not satisfy the demands of an application, it is possible to create bespoke solutions that can also be tested and certified in-house.
Safety, above all
Clearly, the overriding concept for process control within zoned areas is that of safety - there can be no compromise here. In many cases regional certifications are used as a basis for individual, market-specific approvals; for example, components destined to operate in potentially explosive atmospheres may be certified to IECEx Cat2, but in countries such as Korea and China further national testing may be required to meet KOSHA and NEPSI standards respectively
Bürkert continuously monitors approvals requirements to ensure that its products are able to meet the challenges of modern industrial processes, including the creation of all the necessary documentation. With so many regional and national approvals systems, attention to detail is crucial to ensure components are properly accredited.
Paul Hobden is UK ATEX solenoid valve champion at Bürkert.>
Source: Control Engineering Europe - All Articles