HEATED CONTROL PIN

• US 20170056973A1
• Filed: 03/21/2016
• Published: 03/02/2017
• Est. Priority Date: 03/26/2015
• Status: Active Grant

• Current Assignee: Pyrotek High-Temperature Industrial Products Inc.
• Original Assignee: Pyrotek High-Temperature Industrial Products Inc.
• Inventors: BOUCHARD, Jens, BOUCHARD, Michael, TREMBLAY, Sylvain
• Granted Patent: US 9,993,870 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B22D 2/005 for the thickness of a frozen shell B22D11/188 and B22D11/207 take precedence
• CPC Class Codes: B22D 37/00 Controlling or regulating the pouring of molten metal from a casting melt-holding vessel B22D11/18, B22D39/00, B22D41/00 take precedence
• CPC Class Codes: B22D 41/18 Stopper-rods therefor

Abstract

A control pin for controlling the flow of molten metal through a down spout in a casting process is provided. The control pin comprises a body having an elongated shape, a lower portion insertable in the down spout, and a terminal end, opposite the lower portion. The body includes a central core, preferably a hollow tube or a rod of alumina or mullite; a heating element disposed around the central core, and an intermediate layer surrounding the central core and encasing the heating element, the intermediate layer being made of a solidified ceramic putty. Finally, an outer shell, preferably made of woven fiber reinforcing fabric in a matrix of ceramic, surrounds the intermediate layer.

Claims

1. A control pin for controlling flow of molten metal through a down spout in a casting process, the control pin comprising:

a body having an elongated shape, a lower portion insertable in the down spout, and a terminal end, opposite the lower portion, the body comprising;

a central core;

a heating element disposed around the central core,

an intermediate layer surrounding the central core and encasing the heating element; and

an outer shell surrounding the intermediate layer.

2. The control pin according to claim 1, wherein the central core is a hollow tube.

3. The control pin according to claim 1, wherein the central core is made of a material resisting temperatures in excess of 1200°

C.

4. The control pin according to claim 1, wherein the central core comprises alumina.

5. The control pin according to claim 1, wherein the central core comprises mullite.

6. The control pin according to claim 1, wherein the central core is electrically insulating.

7. The control pin according to claim 1, wherein the intermediate layer comprises refractory material.

8. The control pin according to claim 1, wherein the intermediate layer comprises a dried and solidified putty comprising at least one of:

alumina, mullite, silica, silicon carbide, silicon nitride, zirconia, graphite, and magnesia.

9. The control pin according to claim 1, wherein the intermediate layer is dense and solid, without any cavities or voids.

10. The control pin according to claim 1, wherein the heating element is a resistive wire wrapped around the central core.

11. The control pin according to claim 1, wherein the heating element is helically wound around the central core.

12. The control pin according to claim 1, wherein the heating element is capable of generating heat in excess of 1100°

C.

13. The control pin according to claim 1, comprising a radial spacing between the central core and the intermediate layer.

14. The control pin according to claim 13, wherein the radial spacing is less than 1 mm.

15. The control pin according to claim 1, wherein the outer shell comprises layers of a woven fiber reinforcing fabric embedded in a ceramic matrix.

16. The control pin according to claim 15, wherein the woven fiber reinforcing fabric comprises glass.

17. The control pin according to claim 1, wherein the outer shell comprises calcium silicate or silica and a moldable refractory composition.

18. The control pin according to claim 17, wherein the moldable refractory composition comprises at least one of fused silica, alumina, mullite, silicon carbide;

silicon nitride, silicon aluminum oxy-nitride, zircon, magnesia, zirconia, calcium silicate, boron nitride, aluminum nitride and titanium diboride, and mixtures of these materials.

19. The control pin according to claim 1, wherein the central core and the intermediate layer have respective lower extremities, the control pin comprising a tip located at the lower extremities of the central core and of the intermediate layer, the tip being surrounded and embedded in the outer shell.

20. The control pin according to claim 19, wherein the tip comprises a conductive ceramic material and is connected to the intermediate layer with an air-setting mortar or glue.

21. The control pin according to claim 19, wherein the tip comprises one of aluminum nitride (AlN), silicon carbide (SiC) and sialon.

22. The control pin according to claim 1, wherein the outer shell comprises an anti-wetting agent.

23. The control pin according to claim 1, wherein the central core comprises a central cavity, the control pin comprising a thermocouple inserted within the central cavity of the central core.

25. A control pin assembly, comprising:

a control pin according to claim 1;

a thermocouple inserted in the central core; and

a coupling assembly including;

a mechanical support attachable to the terminal end of the control pin; and

an electrical connector affixed to the mechanical support, the electrical connector comprising a first set of electrical connections connectable to the heating element and a set of electrical connections connectable to the thermocouple.

26. The control pin assembly according to claim 25, wherein the mechanical support comprises a casing removably attachable to the terminal end of the control pin.

27. The control pin assembly according to claim 25, further comprising:

a control box comprising a first module controlling current flowing in the heating element; and

a second module monitoring a temperature detected by the thermocouple; and

a cable electrically connecting the first and second sets of electrical connections of the electrical connector to the first and second modules of the control box.

28. The control pin assembly according to claim 27, wherein the control box comprises a processor programmed with at least one heat-up ramp of the heating element, with a rate of at least 150°

C./hour.

29. The control pin assembly according to claim 28, wherein the processor is programmed with more than one heat-up ramp up of the heating element.

24. A control pin for controlling a flow of molten metal through a down spout in a casting process, the control pin comprising:

a body having an elongated shape, a lower portion insertable in the down spout, and a terminal end, opposite the lower portion, the body comprising;

a tube or rod made of alumina or mullite;

a resistive wire wrapped around the tube or rod;

an intermediate layer of dried and solidified ceramic putty, surrounding the tube or rod and encasing the resistive wire;

a tip made of an electrically insulating and heat conducting material, located below the tube or rod and the intermediate layer, and

an outer shell surrounding the tip and the intermediate layer, the outer shell comprising multiple layers of reinforcing fabric, embedded in a ceramic matrix.