10.4
Vacuum Operation and Process Gas Control (if fitted)
Both the vacuum (if fitted) and gas systems are controlled by the temperature
controller/ programmer. Vacuum and process gas injections can only be operated via
program segment events within a temperature program.
Automatic valves control the exhaust gas flow, sending it either via the vacuum pump
or directly to the exhaust chimney.
Note:
The vacuum pump cannot be operated when the furnace is above
50°C.
In a running temperature program, when the vacuum pump is enabled and the furnace
is <50°C, the exhaust valve will close and the vacuum valve will open.
When the vacuum pump is turned off and the gas flow turned on, the vacuum valve will
close and the exhaust valve will remain closed until the retort relative pressure reaches
approxi10mbar, in order to prevent air being sucked back into the retort.
Process gas is controlled by two solenoid valves (low and high flow rates).
In models with manual or semi-automatic gas
system options, the flow rates are set manually
using needle valves. These valves are located in
the furnace base behind the access panel on the
lower right-hand side; this prevents any
inadvertent or unauthorised adjustment of gas
flow rates.
Note:
In models with a fully automatic gas
system, the flow rates are set digitally via the
temperature program
10.4.1
Programming Example
In order for the vacuum and gas systems to work correctly and safely, it is necessary
for temperature programs to follow a specific format.
Note:
The following program is for example purposes only. Please refer to
the separate product documentation pack for programming instructions
relevant to your product.
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