4.4. Summary of structure and function
The vacuum drying oven (hereinafter referred to as the vacuum case) is bench structure. The
vacuum case consists of four parts: case, inner chamber (working chamber), vacuum pumping
system and temperature control system.
The case is made of quality thin steel sheet with bright color plastic surface. The inner chamber is
generally made of galvanized steel sheet or 304 stainless steel sheet. The inner chamber is in a
square of semi-circle corners, and there is super-fine mineral wool filled in between the inner and
outer case as heat insulating material. The door window is made of bulletproof glass OBW
(Observation Window) for convenient observing the samples drying process in the case. There are
one piece of thick armored glass and slide bush inside the case, which are used for connecting the
door, so the slide bush plus spring the armored glass and door seal can even the stress and the
firmly press the door to the rubber O-ring upon closing, without any air leakage in vacuum.
The vacuum pumping system is composed of vacuum pump (optional part), vacuum meter, vacuum
valve and balanced opening. According to user needs, the case can be equipped with dry filtering
tank (filter) or be provided with air inlet as an option (through which other gas can be input into the
working chamber). If the vacuum pump is selected at the user’s discretion, the pumping rate of
the vacuum pump must be ≥ 2L/s
The temperature controller is the main apparatus of the temperature control system, which is a
double-row LED MC smart controller composed of single chip unit and peripheral circuit. The Pt100
platinum is used as temperature-sensing element and the PID regulating mode is used to control the
heating system. The temperature control apparatus also has such functions as timing control,
temperature-control error correction and deviation alarming protection.
The heaters of resistance wire substructure are used for the electric heating system, which are all
mounted inside the shelf panels.
This instrument is advantageous for high temperature control accuracy, less overshooting, less
fluctuation and temperature deviation protection.
