Process Diagram

Steam and water spray process



Process phases:


Phase 1: Heating   
The first operation of the day consists of filling the autoclave with a small amount of water up to the bottom of the baskets (approximately 100 litres per basket). This water can remain in the retort for successive cycles.
With the water at the required level, the steam valve is opened and the recirculation pump starts. The mixture of steam and water spray creates highly turbulent convection currents that quickly even out the temperature at all points in the retort and among the packages.

Phase 2: Mantenance
Once the programmed sterilising or pasteurising temperature has been reached, it is maintained for the set time within a minimum range of +/-0.1 ºC. The pressure is also maintained within +/-0.02 of the programmed value. Unlike traditional steam autoclaves, the pressure may be higher thanks to the injection of compressed air for sterilisation at a higher temperature without causing deformations and avoiding stresses in the closures of the flexible packaging.

Phase 3: Cooling
The retort is equipped with a plate heat exchanger for indirect cooling. The hot water is recirculated through an exchanger where it is cooled by heat exchange with the external cooling water circulating in counter-current through the exchanger's secondary circuit.

Phase 4:  End of process
Once the programmed cooling temperature has been reached, the pressure in the retort is released and the volume of water is reduced to the minimum level. The door is equipped with a safety device that prevents its being opened if there is residual pressure or water above the maximum level.  

Key

1.- Process water inlet

2.- Recirculation pump

3.- Filter

4.- Flowmeter

5.- Heat exchanger

6.- Cooling water inlet

7.- Cooling water outlet

8.- Excess pressure outlet

9.- Level drain

10.- Full drain

11.- Steam inlet

12.- Compressed air inlet