Careful management of the steam through the use of intelligent valves that are directly linked to the temperature sensors, ensures that the steam energy is used in the most efficient manner. These process valves and their installation can also influence the energy efficiency of the compressed air system, which also comprises a significant cost of production.
Most efficient layout and valve design
Creating compressed air is a fundamental, if expensive, requirement for many process control applications, and so employing the most efficient layout and valve design can provide significant savings.
The generation cost of compressed air is equivalent to about 10 per cent of industry's total electricity usage, rising to 30 per cent in some sectors. This highlights why companies have compelling reasons to pursue energy saving initiatives in this area. However, one area of pneumatic energy saving potential is still largely unexploited: improved process valve control techniques.
The centralised control concept is the most traditional of installations but the major drawbacks of this design is the extended control air lines that increase air consumption and the negative effect on the switching times of the valves.
Decentralised automation is a more recent concept. It employs intelligent pneumatic process and control valves for all production processes and utility circuits such as cleaning agents, steam or temperature control.
The use of decentralised automation system, employing innovative intelligent process valves, eliminates the problems of centralised systems, because automation functions – pilot valves, electrical and optical position feedback and fieldbus interfaces – are integrated directly into the actuators of the process valves.
Each process valve is connected directly to the main compressed air supply line in the field, reducing the number and length of tube and cable connections. This approach minimises the number of cables and compressed air lines, which significantly reduces the losses and subsequently the energy costs that are attributed to the compressed air circuit.
Bürkert Fluid Control Systems has developed a range of valve controllers specifically for use in the food, beverage and pharmaceutical industries. These valve units provide a distributed method of opening and closing of process valves automatically, thereby eliminating the need for the wasteful venting of control air, normally associated with pneumatic tubing between the process valve and its related control solenoid valve.
