85
|
P a g e
cascadesciences.com
|
Tel. 503 847-9047
OPERATION
Vacuum System
In addition to the purge and pressurize requirements, the oven does not allow the heating
elements to energize unless the oven chamber is vacuumed down to 0.1 bar (76 Torr) or lower.
The heating elements are automatically depowered if the pressure rises above 0.1 bar.
Vacuum is supplied by an external vacuum pump or building supply system connected to an oven
vacuum port. The oven comes with a vacuum fitting on its back that is opened and closed by the
vacuum valve control on the front control panel. An optional side-mounted hand valve with a KF-25
vacuum fitting may be ordered when purchasing the oven.
Vacuum levels obtained in the oven chamber are dependent on pump type and performance, valve
settings, and the nature of the application or process, including the volume of materials outgassed.
The chamber atmospheric pressure is shown on the touchscreen display homepage. Please see the
topic on page 33 in the Introduction chapter for pump selection and
safety considerations.
Heat Transport in a Vacuum
In conventional ovens, powered elements transfer heat into the chamber air. The heated air then
circulates by natural convection or blower fan action, surrounding the product on the shelves and
gradually bringing it to temperature. In a vacuum oven, heat transport takes place by both direct
infrared radiation and metal-to-metal conduction. The oven heating elements are located inside the
chamber walls or floor, which transfer some heat to the walls and then to the shelves. Each shelf
then transports heat to the products or samples resting on it.
Internal Hotspots
Hotspots form on the chamber floor, walls, and ceiling while the oven is heating. These typically
peak at their highest temperatures when the oven is heating from room temperature to an
application setpoint. The oven is built to prevent these spots from approaching the auto-ignition
temperature of the hazardous material groups allowed in this oven.
Your site-specific baking application SOPs must ensure the oven operates with a safety margin well
below the auto-ignition temperature of any hazardous materials present in the oven chamber. This
safety margin is always for the hottest potential hotspot in the oven chamber and not for the shelf
temperature displayed on the front control panel.
Heating Control
The oven uses a solid-state temperature sensor attached to the exterior of the oven chamber wall.
However, the display shows the oven shelving temperature, which is derived from the chamber
wall measurements and has been confirmed through testing at the factory. A tuned proportional –
integral – derivative (PID) loop is used in controlling power to the heating elements to avoid
significantly overshooting the temperature setpoint. The rate of heating will slow as the oven
shelving approaches the target temperature setpoint. If the chamber temperature is above the
Summary of Contents for CVO-5-EX Series
Page 1: ...Flammable Solvent Ovens Installation Operation Manual CVO 5 EX Oven Series...
Page 6: ...6 P a g e cascadesciences com Tel 503 847 9047 Special Conditions Of Use 131...
Page 7: ...7 P a g e cascadesciences com Tel 503 847 9047 TABLE OF CONTENTS...
Page 11: ...11 P a g e cascadesciences com Tel 503 847 9047 SAFETY CERTS AND STATEMENTS...
Page 17: ...17 P a g e cascadesciences com Tel 503 847 9047 SPECIFICATIONS...
Page 22: ...22 P a g e cascadesciences com Tel 503 847 9047...
Page 24: ...24 P a g e cascadesciences com Tel 503 847 9047 These groups include propane and n butane...
Page 29: ...29 P a g e cascadesciences com Tel 503 847 9047 Continued next page...
Page 37: ...37 P a g e cascadesciences com Tel 503 847 9047 INTRODUCTION...
Page 39: ...39 P a g e cascadesciences com Tel 503 847 9047...
Page 44: ...44 P a g e cascadesciences com Tel 503 847 9047 RECEIVING...
Page 51: ...51 P a g e cascadesciences com Tel 503 847 9047 Continued next page...
Page 54: ...54 P a g e cascadesciences com Tel 503 847 9047 Continued next page...
Page 61: ...61 P a g e cascadesciences com Tel 503 847 9047 End of Procedure...
Page 65: ...65 P a g e cascadesciences com Tel 503 847 9047 INSTALLATION...
Page 67: ...67 P a g e cascadesciences com Tel 503 847 9047 SYMBOLS...
Page 69: ...69 P a g e cascadesciences com Tel 503 847 9047 Continued next page...
Page 72: ...72 P a g e cascadesciences com Tel 503 847 9047 Continued next page...
Page 95: ...95 P a g e cascadesciences com Tel 503 847 9047 End of Procedure...
Page 104: ...104 P a g e cascadesciences com Tel 503 847 9047 End of Procedure...
Page 116: ...116 P a g e cascadesciences com Tel 503 847 9047 End of Procedure...
Page 123: ...123 P a g e cascadesciences com Tel 503 847 9047 Continued next page...
Page 125: ...125 P a g e cascadesciences com Tel 503 847 9047 Continued next page...
Page 127: ...127 P a g e cascadesciences com Tel 503 847 9047 End of Procedure...
Page 128: ...128 P a g e cascadesciences com Tel 503 847 9047 MAINTENANCE...
Page 130: ...130 P a g e cascadesciences com Tel 503 847 9047 REPLACEMENT PARTS...
Page 132: ......