Developed by Cannon and patented in 1979, the FPL* head has since then significantly improved the way moulded Polyurethanes are produced.
The innovation introduced with this "L-shaped" head is that its laminar flow output allows for a splash-free pouring in open moulds, opening the way to a series of new applications and improving the working conditions of the existing ones.
Cannon FPL High-Pressure Mixing Head
Cannon have developed many different types of FPL high-pressure heads, which are specific to particular applications and required performance and have achieved an excellent standard of quality.
Optimum mixing is achieved by the turbulence created by the high velocity impingement of the two components on leaving the jets. Passing from the first to the second chamber the turbulent flow completes the component mixing. The flow, leaving the head, becomes laminar and splash-free.
The reduced size of the Cannon FPL mixing heads and the laminar qualities of the outgoing mix flow make the FPL the perfect instrument for open mould pouring. Furthermore, for automated pour operations, it is possible to specify smaller sized (i.e. cheaper) robots or manipulators while obtaining improved speed and precision performances.
Cannon FPL Standard "L-shaped" high-pressure mixing heads are available in the following model range:
|Total Component Output (*)|
|FPL 7||FPL 10||FPL 14||FPL18||FPL 24||FPL 32|
|Max Laminar Flow||70||150||300||400||700||1850|
|(*) All value are calculated in cc/s, considering a component viscosity < 1000 cps.|
Recycling, essential for ensuring optimum component temperature levels, takes place between the dispensing machine and bypass valve mounted on the feed lines. Low-pressure recycling times are determined by the machine's design. When a pour operation is requested, the bypass valve closes, diverting the component flow into the mixing-head. High-pressure recycling then begins.
This is a short phase preceding the pouring operation, during which the components' pressures are stabilised. Components, passing through externally adjustable jets, flow through two grooves (machined in the mixing chamber piston) and are diverted back, towards their respective storage tanks. In this phase each component's pressure reaches the pre-set value.
At the end of high-pressure recycle the discharge duct piston retracts. When the piston reaches the end of its stroke, a second switch sends the "start pouring" signal to the control system of the dosing unit, either to control the shot weight or to start up the electronic dispense timer. The two liquid components are pulverised one against the other in the small chamber and transform their pressure (about 150-200 bar) into mixing energy.
End of Cycle
The components continue to flow under high-pressure for a few moments in the recycle grooves, ensuring perfect cleaning of the jets. Then the self-cleaning piston passes through the discharge duct, removing any remaining Polyurethane residuals and closing the head. The bypass valve re-opens and restarts the low-pressure recycling phase until the next dispense operation is required.
FPL - AN
Three components high pressure mixing head designed for the axial injection of a third, non abrasive, component (a filler without quarz).
In case of axial injection of a low viscosity stream, excellent mixing is obtained also at lower pressure.
All three streams are recycling through the head.
The mixing head is patented.
FPL - AD
Two components, L-shaped high pressure "armoured" mixing head designed for the use of abrasive fillers pre-blended in the chemical components.
FPL - QCC
Two components high pressure mixing head designed for the quick change of a third component (a colour or any other additive to be injected directly inside the mixing chamber).
The third stream is recycling through a dedicated nozzle and, as a consequence, it can be changed without flushing shots to clean the inside of the head.
A wide range of Cannon Dosing Machines can be equipped with these heads, realizing dedicated and customized applications.