Carbolite CAF DIGITAL IMAGING - Manual (Page 8)

Caf Digital Imaging
page 8
MF36-3.21
3.3. Assembly Of The Furnace.
3.3.1. Element Fitting.
Ensure that the furnace is isolated from the mains supply. Remove the back panel from the
furnace unit.
Note: The heating elements are fitted at the factory to test the furnace but are removed for transit.
These elements are extremely fragile, and can be damaged by contamination: handle them with
care and keep them clean. Avoid touching the heating part.
Slide one insulating collar over each element, then gently slide the element into its hole in the
furnace until the tip of the element locates in the front insulation, see fig 1. If the element does
not slide in freely check that you are holding it in line with the hole; it may help to rotate the
element whilst sliding it in. Only light finger pressure should be required. When the element is in
position slide the insulating collar up against the furnace back insulation.
Use the braids to link the elements and connect them to the terminal posts as shown in fig 1.
Make sure the braids do not touch any other component, or each other.
3.3.2. Installing The Work Tube And Rear Seal Assembly
Ensure that the furnace is isolated from the mains supply, remove the back panel and front panel
from the furnace unit.
Remove the fixing nut and one washer from each of the work tube back support fixing pillars on
the back of the furnace. See fig 6.
Carefully insert the work tube and back seal assembly into the furnace from the back and slide it
through the furnace until the work tube is protruding from the front. The work tube is correctly
positioned when: the work tube insulating collar is in contact with the back face of the furnace
heating chamber, the work tube back support is located over the fixing posts and the
thermocouple sheath is at the top above the vent tube fitting. Secure the work tube back support
in position using the fixings provided. See fig 6.
Note: Take care not to stress the work tube. The work tube back support must be parallel to the
back of the furnace heating chamber and it should not be necessary to bend the back support
fixing posts to locate it.
Connect the numbered thermocouple leads to the thermocouple connecting terminals mounted on
the work tube back support. Ensure correct polarity, the negative legs of the thermocouple are
marked blue, compensating cable colour coding is: Negative = white. Positive = orange.
Make sure the element braids do not touch any metal components of the back tube seal assembly.
3.3.3. Fitting The Work Tube Front Seal Assembly.
Slide the work tube front insulating collar over the front protruding part of the work tube until it
is in contact with the front face of the heating chamber.
Dismantle the front tube seal assembly by removing the six socket screws. See fig 3.
Slide the work tube ring over the front of the work tube with the internal chamfer facing towards
the front. See fig 7.
Fit the tube ‘O’ ring over the front of the work tube and position it uniformly 7.0mm from the
front edge of the work tube. See fig 7.
Fit the work tube gasket to the work tube sealing ring as fig 7, position the work tube sealing ring
on the front end of the work tube and loosely secure to the work tube ring using the six socket
screws provided.
Rotate the front seal assembly so that the swing bolts are positioned horizontally and the gas inlet
fixing is at the lower left side of the work tube. See fig 8.