Frigosystem – Shared expertise for a unique solution
Cooling cycle management solutions
Introduction
The extrusion
Extrusion is a process in which plastic is deformed to create objects of a fixed cross-sectional profile (for example, tubes): the polymer is heated, compressed and pushed through a die with the shape of the profile to be created. When the polymer exits the die it is force-cooled at a controlled temperature by chillers or cooling units to optimize process efficiency and yield. During this phase, precise temperature control is especially important to guarantee the extrudate’s reliability and constant technical characteristics. External ambient factors may have a significant effect on the final product, and therefore the cooling system must be able to detect climatic conditions and incorporate them in the process.
The customer
Frigosystem was founded in 1970 in Italy and specializes in the engineering and manufacturing of innovative industrial chillers and temperature control units. The company operates in the plastics processing industry, in flexography, converting, packaging, and wood, as well as in hi-tech sectors such as the aerospace industry.
Innovation is the main focus in all applications: cutting-edge technologies achieve high-quality solutions that are simple to use and adapt to the demands of sales markets.
The process
Chillers are machines that remove heat by means of vapor compression/expansion cycles and passages through heat exchangers. The controlled chilling phase is essential in plastics extrusion and demands precise temperature control, which consumes a considerable amount of energy.
Frigosystem offers high-energy-efficiency chillers that are suitable for installation in any climate zone, combined heating and cooling units, and all-in-one monobloc units with various flow rates and temperatures for single or double cooling ring. For example, the KITE monobloc unit for blown film extrusion guarantees the lowest energy consumption and shortest payback time of any unit on the market.
The problem
The chilling cycle has various steps that require control, for example, of compression pumps, turbines for heat exchangers, valves for flow of liquid/vapor and, of course, temperature.
In addition to a precise thermoregulator (control of air temperature with maximum tolerance of ±0.4ºC and ability to operate with different water temperatures), Frigosystem also needed to control machine states by managing inputs and outputs to control pumps, etc., and to clearly provide operators with “classic” temperature control information (PV, SV, etc.) as well as the state of actuators and their alarms, temperature alarms, and much more.
The solution
Gefran’s new 1350 series controller offers a series of standard features that allowed Frigosystem to manage part of the options required:
- Blocks with logic functions
- 16 timers
- Scrolling messages in multiple languages
The complexity of the application required additional customization, and Frigosystem and Gefran worked together to create a powerful, custom unit that manages:
- Pump START/STOP via digital inputs, with interlocks
- Fan temperature alarms
- Pump stop cycle with timers in case of low level alarm
- Configurable, password-protected Man/Auto start selection
- Smart management of fan work load: based on the deviation between measured and set temperature, the cooling fans are started alternately to evenly distribute their wear.
In addition to the main process functions, great importance was given to the operator interface: a pad print with symbols specified by Frigosystem was affixed at the state signal LEDs on the front of the controller, so that the operator can clearly see the work phase and the presence of any alarms at all times.