Cascade TEK CTVR522-H, Инструкция по установке и эксплуатации

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OPERATION
T
HEORY OF
O
PERATION
Vacuum and Vacuum Automation
Atmosphere is pumped out of the oven chamber through a pneumatic vacuum valve on the back of
the oven and then exits through the roughing vacuum pump connected to the valve. The valve
position is controlled by either the Full Vacuum or Vacuum Control functions. Full Vacuum opens the
valve all the way, allowing the maximum flow rate to pump down the chamber. The Vacuum Control
function dynamically positions the valve to achieve and then maintain a vacuum setpoint between
room pressure and 1 Torr in the chamber.
The pump is turned on or off using the Pump Start function. The current vacuum level is displayed on
both the Vacuum Gauge display and the Main controller homepage vacuum tab.
The oven is intended for use in closed-cycle applications with the oven chamber partly or fully
pumped down while controlling temperature. The lowest possible chamber pressure is dependent
on both the pump type and the volume of outgassing from product or samples in the chamber.
Heating the oven with atmosphere in the chamber can oxidize the chamber surfaces.
Backfilling
The oven controller opens the pneumatic vacuum port when either the Full Vacuum or Vacuum
Control functions are on. As soon as both these functions are turned off, the oven closes the vacuum
valve, then opens the automated backfill port. This backfills the chamber to approximately 600 Torr.
To restore the chamber to full room pressure (approximately 810 Torr N
2
/ 760 Torr atmosphere), the
operator manually presses and holds the Stop / Backfill button on the control panel.
The oven backfills using room atmosphere unless a clean or inert gas supply is connected to the
push fitting Backfill / Vent port fitting on the back, left side of the oven. The maximum allowed backfill
pressure is 15 psi of delivery at the port. Inert gases, such as nitrogen (N
2
), are typically used to avoid
oxidizing the chamber surfaces or product as well as avoid particulate contamination and introducing
water vapor into the hot chamber. Clean air can also be used to avoid water and particulate
contamination.
Temperature Modes
The oven operates in one of two heating modes: A single constant temperature setpoint or
executing an operator-programmed, multistep heating profile.