Cannon HE-System Polyurethane Metering Unit

The piston-driven HE-System metering unit has represented the most versatile system available for polyurethane formulations that use abrasive filler, a high level of nucleation gas or high viscosity components.

Component metering is achieved by means of hydraulically-driven metering pistons. A single motor/pump moves oil from the tank to the proportional valves - one for each metering cylinder. Each proportional valve controls the quantity of oil needed to provide the required component output from the metering cylinders.

An encoder continuously measures the speed and position of each cylinder. The digital system constantly checks performance parameters during the pouring phase, comparing actual parameters to set values. In case of deviation from the set values, the control modifies the setting of the relevant hydraulic proportional valve, adjusting output and ratio values in real time.

The speed at which the HE can switch its pour program (sometimes required within the same mould pour) and its consistent results, make it ideal for coupling with a head carrier robot for such applications where varying foam properties are required between areas of the same part. Applications may include back foaming of automotive trim components, insulating carpets, and components where perfect distribution of foam is necessary such as bumpers and automotive body parts

Cannon "HE-System" 60

Main Advantages

Reliability. The piston-metering concept provides the lowest downtime.
Lowest maintenance requirements of PU machines. There are no rotating parts in contact with components. Low-speed, linear movement of the dispensing pistons virtually eliminates chances of leakage.
Precision. Accurate closed-loop control of the piston speed assures accurate and repetitive metering of the polyol and isocyanate.
Repeatability. The ability of the HE to self-set and self-adjust eliminates manual calibration operations and traditional ratio control devices.

Technical Characteristics

Output ranges of 20 to 750 kg/min.
Dispensing cylinder, which determines the maximum size of the piece that can be obtained: available in 3, 7, 13, 25 litre versions (available volume for pouring: 92% of cylinder volume).
Shortest pouring time: 0.2 sec (200 msec).
Self-adjusting time (closed loop): 0.028 sec (28 msec).
Digital acquisition of output values, free from calibration and error compensations.
99 pouring programs, expandable to 999.
Electronic programming table.
Supplied in the basic configuration with 24 digital inputs, 8 analog inputs, 16 digital outputs, 4 outputs at 110V.
Availability of special laboratory tanks (24 litres instead of 330) that allow reduction of the minimum quantity usable in the machine for the setting up of the new formulations and short test runs.
Capacitance level sensors with four working positions mounted on the tanks: they replace traditional float systems. Calibration for various minimum and maximum values is possible and there are no moving mechanical parts. Available with analog or digital display.
Double-column air dryer model with automatic regeneration. It eliminates all traces of humidity from the compressed air, thus avoiding problems of unwanted reactions with the components contained in the tanks.
Shell and tube heat exchangers mounted on pipes carrying components to the tanks. Recommended for all those applications where there could be problems of components overheating during recycling (fast cycles, long piping, viscous components).