Burkert was recently asked by Buck Systems to supply pneumatic control systems for equipment in an advanced tablet plant in Asia. Neil Saunders, of Burkert UK, describes the project
Burkert Fluid Control Systems has designed and manufactured a complete pneumatic control system for vibrating pharmaceutical powder mixing and delivery systems for a large tablet manufacturing plant commissioned in Asia.
The control system, commissioned by Buck Systems (part of GEA Pharma Systems), is built around Burkert's AirLINE pneumatic valve islands that allow a variety of digital and analogue input/output (I/O) signals to be combined with process field bus (Profibus DPV1) connection and external vendor digital computers (PLCs). The complete panel systems are supplied fully built in stainless steel cabinets, tested and provided with a certificate of conformity.
In addition, for this project Burkert Side Control electro-pneumatic positioners were used to control double-seated hygienic Buck butterfly valves that regulate the flow of powder from large hoppers. The control units are mounted remotely from the process valve bodies and provide the rotary actuators with precise positional control signals using an integral process controller (PID) and an external position sensor. They also provide a digital status display and manual programming override controls from an integral keypad.
The hoppers are vibrated to ensure a smooth powder flow and no "sticking" to the sides. The control cabinets are isolated from the majority of the vibration equipment, but are exposed to some continuous vibration and had to be designed to cope with this tough operating environment.
The electro-pneumatic control panels contain a variety of ancillary equipment: filter regulators, pressure switches, various DIN rail mounted terminals and Wago I/O blocks, all of which had to be firmly attached and tested. Weighing equipment and HMIs (from Mettler Toledo) were also integrated into the control cabinets along with Siemens PLCs.
Burkert was given a precise working requirement for the control systems and was able to go away and design a complete solution - arguably the overriding factor in Burkert being selected to complete this project.
The control cabinet layout is extremely neat and rationalised, due mainly to the flexibility of the AirLINE valve island system. All the typical benefits of using a fieldbus system (DeviceNet in this instance) are gained by using AirLINE, which plugs directly into I/O modules and DIN rail mounted PLCs from the main vendors. This reduces wiring significantly and ensures that the clients can talk to a wide variety of sensors, positional control feedback, HMIs and other equipment producing a variety of digital and analogue signals that can be brought into one place and integrated with the latest pneumatic valves.
The islands also allowed for the control of air for actuation and piloting for the lower pressure, higher flow rate valves used to control the air that carries the powders around the system.
The AirLINE 8644 system overcomes plant standardisation and communication protocol issues by integrating Burkert high performance solenoid valves with analogue and digital I/O modules and fieldbus communications from all market-leading PLC vendors.
Calculated to save up to 40% on total system costs through the engineering efficiencies achieved, the series 8644 provides users with a remote field I/O network that is compact, reliable and not exclusive to any specific communication protocol.
The remote process actuation and control system combines digital I/O, including a full complement of solenoid pilot valve outputs, digital and analogue I/O, including direct RTDs and T/Cs, and speciality signals (RS232, high speed counters, etc) into a single node.
The system enables pneumatic solenoid valves to be electrically connected directly to a remote I/O module, without any individual coil wiring, numbering or termination required; each valve is simply a digital output addressed by the network. Depending upon the application, the system can incorporate up to 13 modules (2x and 8x module types), with a maximum of 64 valves accepted. mc
