MOISTURE RESISTANT LAYERED SLEEVE HEATER AND METHOD OF MANUFACTURE THEREOF
A method of forming a layered heater assembly includes: forming a plurality of layers onto a substrate, the plurality of layers including a resistive element layer; forming electrical terminations in contact with the resistive element layer; securing a protective cover over the layers using a laser welding process, wherein edges of the protective cover are welded circumferentially around raised end portions of the substrate and welded longitudinally along a slotted portion of the substrate; securing a pair of lead wires to the electrical terminations; and securing a lead cap assembly around the pair of lead wires and to the protective cover using a laser welding process.
1 . A method of forming a heater assembly comprising:
forming a plurality of layers onto a substrate using a thermal spray process, wherein a recessed area for a termination is disposed on the layers;
forming electrical terminations proximate the recessed area;
securing a protective cover over the layers using a laser welding process, wherein edges of the protective cover are welded circumferentially around raised end portions of the substrate and welded longitudinally along a slotted portion of the substrate;
securing a pair of lead wires to the electrical terminations within the recessed area; and
securing a lead cap assembly around the pair of lead wires and to the protective cover.
2 . The method according to claim 1 , wherein the plurality of layers includes a resistive element layer that is formed by a laser removal process.
3 . The method according to claim 1 , wherein the lead wires are secured to the electrical terminations using a laser welding process.
4 . The method according to claim 1 , wherein the lead cap assembly is secured to the protective cover using a laser welding process.
5 . The method according to claim 1 , wherein the lead wires are secured to the electrical terminations with a termination spring, and the termination spring is severed after the termination spring is secured to the electrical terminations.
6 . A method of forming a layered heater assembly comprising:
forming a plurality of layers onto a substrate, the plurality of layers including a resistive element layer;
forming electrical terminations in contact with the resistive element layer;
securing a protective cover over the layers using a laser welding process, wherein edges of the protective cover are welded circumferentially around raised end portions of the substrate and welded longitudinally along a slotted portion of the substrate;
securing a pair of lead wires to the electrical terminations; and
securing a lead cap assembly around the pair of lead wires and to the protective cover using a laser welding process.
7 . The method according to claim 6 , wherein the plurality of layers are formed by a thermal spray process.
8 . The method according to claim 6 further comprising forming a recessed area for the electrical terminations.
9 . The method according to claim 6 , wherein the resistive element layer is formed by a laser removal process.
10 . The method according to claim 6 , wherein the lead wires are secured to the electrical terminations with a termination spring, and a portion of the termination spring is severed after the termination spring is secured to the electrical terminations.
11 . A method of forming a heater assembly comprising:
preparing a substrate having an outer surface and a recessed area recessed from the outer surface;
thermally spraying a resistive layer on the outer surface of the substrate;
forming a pair of terminal pads in the recessed area and connecting the terminal pads to the resistive layer; and
securing a protective layer to the substrate to protect the resistive layer and the terminal pads against moisture intrusion.
12 . The method according to claim 11 , wherein the protective layer defines an aperture.
13 . The method according to claim 12 , further comprising aligning the aperture with the terminal pads.
14 . The method according to claim 12 , further comprising inserting a pair of leads wires through the aperture to connect the pair of lead wires to the terminal pads.
15 . The method according to claim 14 , further comprising securing a pair of lead wires to a termination spring.
16 . The method according to claim 15 , further comprising placing the termination spring in the recessed area to connect the termination spring to the terminal pads.
17 . The method according to claim 16 , further comprising severing the termination spring into at least two pieces so that the terminal pads are electrically disconnected.
18 . The method according to claim 14 , further comprising inserting the lead wires through a lead cap assembly.
19 . The method according to claim 18 , further comprising securing the lead cap assembly to the protective layer.
20 . The method according to claim 18 , further comprising laser-welding the lead cap assembly to the protective layer.