Critical case for reliability

Pneumatic control has been in use for many years, especially in the pharmaceutical, food and beverage industries, where hygienic conditions must be maintained.

Pneumatics have many advantages, including simplicity of design, low maintenance requirements, and excellent reliability due (in part) to the use of compressed air as the power source. In addition, these systems are intrinsically safe and so can also be used in hazardous atmospheres, such as those in the petrochemical industries.

Modern control systems can be divided into two groups, centralised and decentralised. A centralised control solution is the more traditional one and will usually involve a control panel containing a bank of control solenoids that are connected to the process control valves using air lines alone.

In a decentralised system, the air supply is fed direct to the control valve and the integral control head uses control signals to determine what action is required. The choice of system is dependent on the application, the crucial point is to ensure that the system is properly designed and installed to ensure efficient and reliable operation.

Once the design scope is agreed, even for the simplest of installations, it is important to ensure the proposed design will produce an effective and efficient control system which will be easy to maintain, expand, and (if necessary) clean to the required standard.

Although many of the components used in a pneumatic control system are relatively inexpensive, the cost of generating the compressed air is not, so it is crucial the air is used in the most efficient way.

This also impacts the ‘green rating’ of your process line, which is increasingly impacting profitability, and being reported on the ‘triple bottom line’.

The first step is to clean and regulate the compressed air supply to the control system using air preparation units that filter and regulate the air supply. These units remove water and oil aerosols while also controlling the system air pressure all of which makes them crucial to ensuring correct operation of the system as well as reducing wear and corrosion of the components.

Burkert offers standardised filterregulator air preparation units, with and without isolation valve kits, for all manifold sizes available from local stores.

Air preparation units are available with a range of filter sizes, down to 0.01μm, as well having the option of an activated carbon filter that can remove oil aerosols to a level of less than 0.005 mg/m3. In addition, a range of connection sizes is available, plus explosive environment certification to comply with regulations when operating in hazardous atmospheres.

As the system starts to take shape, so there is a need for flow restrictors, oneway valves and check valves to ensure the air pressure and flow direction is correct for the equipment it is supplying. These need to be matched to the application with regard to construction material, sealing properties and connection sizes, to ensure reliable and efficient service.

Bürkert has developed a wide range of products for use in pneumatic process control systems as well as a process for designing, building, installing and commissioning complete systems.

From the simplest closed loop control system, to the largest factory wide production facility with the latest fieldbus communications and intelligent control valves, Burkert has the experience and expertise to deliver a range of reliable, efficient and economic projects.