Orved A Mode D'emploi Et D'entretien page 51

VACUUM CHAMBER
PACKAGING MACHINES
b) Models without vacuum sensor (timed program).
In machines with this type of program (models A - B - C - D - F), the VAC parameter is timed and expressed in seconds. The VAC time setting must
be suitable for actual operating requirements. The time will be initially set approximately at 25-30 seconds and modified, if necessary, in the second
cycle. To obtain absolute vacuum, starting from the moment the vacuum gauge indicates -1.0 bar, the pump will continue to run for another 10
seconds. In machines with VAC parameter time setting, there is no provision for the VAC+ function.
Packaging liquid products.
Great care must be taken in packing liquid products or products with high moisture content: the greater the vacuum percentage, the lower the liquid
boiling point.
The moment the boiling point is reached, air bubbles are formed in the product.
The consequent formation of water vapour, if extracted by the pump, will reduce the pump life.
WARNING! Before starting with packing of liquid products, run the pump by adjusting the VAC control knob or key to the
maximum value and resetting all other functions. Repeat the operation twice, in order to obtain a pump heating time of
about 2 minutes.
Set the vacuum parameter at such a value as to prevent boiling of the liquid product.
Increase the pump oil change frequency by following the instructions in the "MAINTENANCE" chapter.
Stop the work cycle immediately if liquid starts leaking out of the bag. The operation must be carried out with an inclined table
top for liquids, available as optional.
5.5.2 GAS FUNCTION (OPTIONAL)
Product packaging by flushing with gas is available as optional. The GAS option makes it possible to pack delicate products without pressing due to
pressure difference. To compensate for this pressure difference, the air is replaced with a controlled gas mixture generally consisting of 30%
carbon dioxide and 60% nitrogen. It is also possible to use antioxidant gas mixtures which help prolong the shelf-life. To select the suitable mixture,
consult the information leaflet of the best gas production Companies.
The maximum permitted percentage of gas is 60%. This percentage represents the chamber volume occupied by the gas. Beyond the 60% limit, the
pressure exerted by the sealing bar on the bag may be insufficient and bag sealing may be defective. The percentage is read by the vacuum gauge:
-0.4 bar corresponds to a gas value equal to approx. 60%; at -0.3 bar it is equal to 60% and so on. If the cover opens during the cycle, reduce the
gas flushing time. In versions with digital control, the percentage is indicated directly on the display.
5.5.3 SEALING FUNCTION (SEAL)
After vacuum creation and gas flushing (if envisaged), the machine proceeds with bag sealing by means of the sealing bar provided with sealing
wire. The sealing time varies according to the bag basic weight, environmental temperature and the quantity of work to be done. In any case, the seal
seam on the bag must be uniform, clearly marked, without melted points. In machines with electro-mechanical controls, indicatively, for a bag with
basic weight 90/100 (very thin), set the SEAL control knob on value 3.5; for bags with basic weight 150/100 (thicker) adjust the value to 4. In digital
versions, set a sealing time suitable for the bag, approximately between 2 and 4 seconds.
If it is found to be necessary to seal very thick bags, or bags made of special material (such
as aluminium), the models L - N - P - Q are provided with a compressed air connection (A)
to increase the pressure exerted on the sealing bar. The pressure must be adjusted upline of the
air delivery pipe by means of the pressure regulator set at a maximum value of 1 bar. The use
of compressed air in sealing is quite rare, since the pressure exerted by the machine's system is
sufficient in almost all cases.
5.5.4 SOFTAIR FUNCTION (OPTIONAL)
Slow devacumation in the vacuum chamber after bag sealing makes it possible to pack delicate products or products with sharp cutting edges (e.g.
hard cheeses, speck, raw ham, ribs etc.) thereby avoiding damage to the bags due to excessively rapid decompression.
For packing cheese segments it is advisable to smooth the edges.
The parameter is set on a timed basis by means of the SOFTAIR control knob in versions with electro-mechanical controls ("SOFTAIR" key in the
digital versions). The optimum value can be determined after a few test runs before packaging the product in series.
5.5.5 JARS FUNCTION (B)
With the JARS function, it is possible to create vacuum in external containers (vacuum box) in
models provided with a special valve or pack channelled bags that are longer than the standard
dimensions permitted by the vacuum chamber, outside the machine.
In versions with elctro-mechanical control, the parameter setting is manual and is done by
turning the VAC knob to OFF.
The function is deactivated manually by turning the VAC control knob to the preset value, after
maximum vacuum is achieved (measured by the vacuum gauge).
In the digital versions, the JARS function is activated by means of the JARS key. The function is
deactivated manually after the maximum vacuum is achieved, measured by the vacuum gauge.
REV. 00 - Cod.: 1500159
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INSTALLATION
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AIR
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Operation and maintenance manual / Ed. 02 - 2006
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GB
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