1. A method of forming an electric heater suitable for heating molten metal, the electric heater comprised of a tube having a closed end for immersing in the molten metal, the tube comprised of a composite material, the method comprising the steps of:
(a) providing a tube having a coefficient of thermal expansion less than 8\xd710\u22126 inin\xb0 F. and having an outside surface;
(b) applying a bond coat to the outside surface;
(c) applying a refractory coating to said bond coat;
(d) applying a metal sealant to said refractory;
(e) converting said metal sealant to provide a transformed metal sealant resistant to reaction by said molten metal; and
(f) locating an electric heating means in said tube.
2. The method in accordance with claim 1 including applying said metal sealant by vapor deposition.
3. The method in accordance with claim 1 including applying said metal sealant by immersing in molten metal sealant.
4. The method in accordance with claim 1 wherein said metal tube is fabricated from a metal selected from the group consisting of titanium, titanium alloys, stainless steel, nickel based alloys and iron based alloys.
5. The method in accordance with claim 1 wherein said bond coating comprises an alloy selected from the group consisting of Cr\u2014Ni\u2014Al alloy, a Cr\u2014Ni\u2014Al\u2014Y alloy and a Cr\u2014Ni alloy.
6. The method in accordance with claim 1 wherein said refractory coating is selected from the group consisting of one of Al2O3, ZrO2, Y2O3 stabilized ZrO2, SiAlON and Al2O3\u2014TiO2.
7. The method in accordance with claim 1 wherein said metal sealant is selected from the group consisting of Mg, Al, Zn, Ca and Y.
8. The method in accordance with claim 1 wherein said oxidized metal sealant is magnesium oxide.
9. The method in accordance with claim 1 including converting the said metal sealant to a metal oxide.
10. An electric heater assembly suitable for immersion heating molten metal, the electric heater assembly comprised of
a tube having a closed end suitable for immersing in molten metal, the tube fabricated from a composite material comprised of a case having a coefficient of thermal expansion of less than 10\xd710\u22126 inin\xb0 F. and having an outer surface coated with a refractory coating having a coefficient of thermal expansion less than 10\xd710\u22126 inin\xb0 F.;
the refractory coating having a metal sealant applied thereto, the metal sealant oxidized to provide an oxidized metal sealant in pores of the refractory coating, the oxidized metal sealant resistant to attack by said molten metal.
11. The electric heater in accordance with claim 10 wherein the metal case is selected from a metal selected from the group consisting of titanium, titanium alloys, stainless steel, nickel based alloys and iron based alloys.
12. The method in accordance with claim 10 wherein said metal sealant is selected from the group consisting of Mg, Al, Zn, Ca and Y.
13. The method in accordance with claim 10 wherein said oxidized metal sealant is magnesium oxide.
14. A method of forming an electric heater suitable for heating molten metal, the electric heater comprised of a tube having a closed end for immersing in the molten metal, the tube comprised of a composite material, the method comprising the steps of:
(a) providing a metal tube having a coefficient of thermal expansion less than 8\xd710\u22126 inin\xb0 F. and having an outside surface;
(b) applying a bond coat to the outside surface;
(c) applying a refractory coating to said bond coat;
(d) heating said refractory coating to cause formation of micro cracks and to form oxides of metals comprising said bond coat and metal tube in said micro cracks to render said refractory coating resistant to corrosive attack by said molten metal; and
(e) locating an electric heating means in said tube.
15. The method in accordance with claim 14 including heating said coating to a temperature range of 400\xb0 to 2200\xb0 F.
16. The method in accordance with claim 14 wherein said metal tube is fabricated from a metal selected from the group consisting of titanium, titanium alloys, stainless steel, nickel based alloys and iron based alloys.
17. The method in accordance with claim 14 wherein said bond coating comprises an alloy selected from the group consisting of Cr\u2014Ni\u2014Al alloy, a Cr\u2014Ni\u2014Al\u2014Y alloy and a Cr\u2014Ni alloy.
18. The method in accordance with claim 14 wherein said refractory coating is selected from the group consisting of one of Al2O3, ZrO2, Y2O3 stabilized ZrO2, SiAlON and Al2O3\u2014TiO2.
19. An electric heater assembly suitable for immersion heating molten metal, the electric heater assembly comprised of
a tube having a closed end suitable for immersing in molten metal, the tube fabricated from a composite material comprised of a metal case having a coefficient of thermal expansion of less than 10\xd710\u22126 inin\xb0 F. and having an outer surface coated with a refractory coating having a coefficient of thermal expansion less than 10\xd710\u22126 inin\xb0 F.;
the refractory coating oxidized by heating in a temperature range of 400\xb0 to 2200\xb0 F. to provide an oxidized metal in micro cracks of the refractory coating, the oxidized metal rendering the refractory coating resistant to attack by said molten metal.
20. The electric heater in accordance with claim 19 wherein the metal case is selected from a metal selected from the group consisting of titanium, titanium alloys, stainless steel, nickel based alloys and iron based alloys.
21. The method in accordance with claim 19 wherein said refractory coating is selected from the group consisting of one of Al2O3, ZrO2, Y2O3 stabilized ZrO2, SiAlON and Al2O3\u2014TiO2.
22. The method in accordance with claim 19 wherein said bond coating comprises an alloy selected from the group consisting of Cr\u2014Ni\u2014Al alloy, a Cr\u2014Ni\u2014Al\u2014Y alloy and a Cr\u2014Ni alloy.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A safety buckle, comprising:
a socket having a cavity with a first surface;
a first catch in the cavity and adjoining the first surface and protruding away from the first surface;
a plug with a central arm for insertion into the socket;
a first latch on the central arm sized and positioned to cooperate with the catch when the plug is inserted into the socket to engage the plug and socket;
a disengagement device on the socket or plug cooperating with the central arm or the catch to disengage the latch and the catch upon actuation of the device; and
a second latch or catch sized and positioned with a symmetry to the first latch or first catch, respectively, for providing an alternate engagement with the corresponding first catch or first latch, such that the socket and plug may be engaged independent of a relative orientation of the socket and plug.
2. The buckle according to claim 1, wherein:
the socket includes the second catch; and
the first latch is a protrusion on the central arm.
3. The buckle according to claim 1, wherein the central arm includes the second latch for cooperating with the first catch of the socket.
4. The buckle according to claim 1, further comprising two central arms, one central arm including the first latch and the other central arm including the second latch.
5. The buckle according to claim 1, wherein the central arm further comprises a pair of latches, each of which being suitable for cooperating with the catch of the socket.
6. The buckle according to claim 1, wherein the cavity includes a second surface opposing the first surface and symmetrical openings in the first and second surfaces forming the first and second catches, the openings being sized and shaped to cooperate with the first latch on the central arm of the plug, wherein the device is a button coupled to a lever operable to displace the latch to prevent cooperation between the latch and the openings.
7. The buckle according to claim 1, further comprising two central arms, one having the first latch and the other having the second latch; and
two opposed openings in the cavity for cooperating with the first and second latches of the central arms.
8. A safety buckle, comprising:
a first buckle member including a first engagement part;
a second buckle member including a second engagement part;
the first and second buckle members being complementary shaped to provide an interactive fit when the first and second buckle members are fitted together;
the first and second engagement parts being cooperative to retain the first and second buckle members together when the first and second buckle members are fitted together;
one of the first and second engagement parts having a symmetrically functional counterpart, such that the first or second engagement part cooperates with the counterpart to retain the first and second buckle members together when the first and second buckle members are fitted together in a different orientation.
9. The safety buckle according to claim 8, further comprising a central arm on one of the first or second buckle members, the first or second engagement part being located on the central arm.
10. The safety buckle according to claim 9, wherein the counterpart is located on an opposite side of the central arm from the first or second engagement part.
11. The safety buckle according to claim 9, wherein the counterpart is located on the other of the first or second buckle member from that having the central arm.
12. The safety buckle according to claim 8, further comprising two central arms on one of the first or second buckle members, one central arm having one of the first or second engagement parts thereon, and the other central arm having the counterpart.
13. The safety buckle according to claim 9, wherein the engagement part on the central arm is formed as a recess with a shoulder near an end of the central arm, the counterpart also being arranged on the central arm.
14. The safety buckle according to claim 8, further comprising:
a cavity in one of the first or second buckle members to receive an interacting portion of the other of the first or second buckle members; and
the first or second engagement part is provided as a projection in the cavity to cooperate with the other of the first or second engagement parts, the counterpart also being located in the cavity.
15. The safety buckle according to claim 8, further comprising a disengagement device on one of the first or second buckle members for disengaging the first or second engagement parts or counterpart to permit the buckle to be unclasped.
16. The safety buckle according to claim 15, wherein one of the first or second engagement parts is located on the disengagement device.