Thermcraft provides element refurbishment service for vertical furnaces (Figure 1). This article discusses the typical rebuild process performed at Thermcraft.
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Figure 1. Thermcraft provides element refurbishment service for vertical furnaces.
Typical Rebuild Process
After the receiving failed elements from customers, Thermcraft disassembles them and recovers the outer water cooled shell, machined metal bases and interior metal components, including the inner metal liner. Thermcraft then removes and discards the element coil and insulation.
Thermcraft checks whether the ceramic spacers are in good reusable condition. Similarly, all metal components are checked for wear and damage and may be reused based on their condition.
Based on the requirement, the replacement of the damaged components is carried out with additional charges. However, such instances are very rare.
Resistance wires of the same type (A-l or APM) and gauge as the OEM are used when winding the new element coil. Ceramic spacers are securely positioned. The coil is provided with new lead taps that are welded at the same position as the original. The finished coil is then covered with new ceramic fiber insulating blanket layers, followed by re-assembling of the water cooled jacket, insulating vestibules, metal bases and the shell.
The element is then heated to dry out organics and moisture, and drying takes place from the inside out. This is followed by a finishing step and final QC process. This includes verification of element resistance and dimensions and confirmation of all details provided in the drawing against the refurbished element. The final step is the packaging and shipping of the rebuilt element to the customer. Partial P/Ns cross reference list is given in Table 1.
Table 1. Partial P/Ns cross reference list.
OEM |
OEM PT#: |
Thermcraft PT#: |
KOKUSAI NO. |
D4EX03531/Low Mass
D4EX03531/Heavy Ga. |
AD-1404FC200
AD-1404DC1300 |
KOKUSAI NO. |
D4EX02648 |
AD-1420FC200 |
KOKUSAI NO. |
D4EX03531 |
AD-1437FC200 |
KOKUSAI NO. |
4037440 |
AD-1439DC1300 |
KOKUSAI NO. |
D4EX04882 |
A D-1444DCHT500 |
KOKUSAI NO. |
F-270W-81 VR4Z |
AD-1447DC1300 |
KOKUSAI NO. |
D4EX08455-4 |
AD-1448FC200 |
TEL |
VMU-40-003 |
AD-1318DCHT500 |
TEL |
VMM-40-101 |
AD-1339S-A |
TEL |
VMU-40-007 |
AD-1354DCHT500 |
TEL |
VMU-32-001 |
AD-1365DCHT500 |
TEL |
VMU-28-017 |
AD-1395DCHT500 |
TEL |
VMM-40-102EX |
AD-1436S-A |
TEL/KOREAN |
VMU-40-003 |
AD-1446DCHT500 |
TEL |
VOS-40-017 |
AD-1415S-A |
SVG |
165558-003 |
AD-1352DCHT500 |
SVG |
602783-03 |
AD-1360SP-03-A |
SVG |
602783-02 |
AD-1429SP-01-A |
Conclusion
The careful reverse engineering of each refurbished element exactly reproduces the original component. The element components employed are the same parts used by the OEM, thereby providing a rebuilt component that has the same dimensional, operating and electrical features of the original component. Refurbishing failed components with the help of Thermcraft's craftsmen and engineers is a cost-effective solution compared to replacing with completely new elements.

This information has been sourced, reviewed and adapted from materials provided by Thermcraft.
For more information on this source, please visit Thermcraft.