NOVEL DESIGNS FOR AN ELECTRIC WARMING BLANKET INCLUDING A FLEXIBLE HEATER
An electric warming blanket includes a flexible heater that may be enclosed within a flexible shell, which is, preferably, water resistant and may extend beyond lateral edges of the heater to support stiffening members. A layer of non-conductive flexible porous material may be bonded to one or both sides of the heater. When the heater is enclosed in the shell, a layer of thermal insulation may be disposed between one side of the heater and the shell. A temperature sensor may be coupled to the heater at a location where the heater will be in conductive contact with a body when the blanket is draped thereover, and at least one super-over temperature sensor may also be coupled to the heater; the at least one super over-temperature sensor is adapted to interrupt a supply of power to the heater.
1 . An electric warming blanket, comprising:
a flexible heater including a first side and a second side, at least one of the first and second sides having a surface area and a substantially uniform watt density output across the surface area when the element is electrically powered;
a first layer of non-conductive flexible porous material bonded to the first side of the heater;
a second layer of non-conductive flexible porous material bonded to the second side of the heater; and
a first layer of water resistant material coupled to a second layer of water resistant material about a perimeter of the heater to form a substantially hermetically sealed space for the heater and the first and second non-conductive material layers bonded thereto.
2 . The blanket of claim 1 , wherein the heater comprises carbon.
3 . The blanket of claim 1 , wherein the heater comprises a nonconductive layer coated with a conductive material.
4 . The blanket of claim 3 , wherein the nonconductive layer of the heater comprises a woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
5 . The blanket of claim 3 , wherein the nonconductive layer of the heater comprises a non-woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
6 . The blanket of claim 3 , wherein the non-conductive layer of the heater comprises a non-woven cellulose material and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
7 . The blanket of claim 1 , wherein each layer of non-conductive flexible porous material comprises a woven fabric.
8 . The blanket of claim 7 , wherein the woven fabric is formed of a non-flammable material.
9 . The blanket of claim 7 , wherein the woven fabric is fiberglass or cotton.
10 . The blanket of claim 1 , wherein each layer of non-conductive flexible porous material comprises a non-woven fabric.
11 . The blanket of claim 10 , wherein the non-woven fabric comprises nylon or fiberglass.
12 . The blanket of claim 1 , wherein each layer of non-conductive flexible porous material comprises a polymeric foam.
13 . The blanket of claim 1 wherein the first layer of water resistant material extends adjacent to the first layer of non-conductive flexible porous material and is un-adhered thereto.
14 . The blanket of claim 13 , wherein the second layer of water resistant material extends adjacent to the second layer of non-conductive flexible porous material and is un-adhered thereto.
15 . The blanket of claim 1 , further comprising:
a first conductive bus bar coupled to the first side of the heater and extending alongside a first lateral edge of the heater; and
a second conductive bus bar coupled to the first side of the heater and extending alongside a second lateral edge of the heater;
wherein the first lateral edge is opposite the second lateral edge;
the first and second bus bars are contained in the substantially hermetically sealed space formed by the first and second layers of water-resistant material; and
the first and second bus bars are adapted for coupling to a power source for powering the heating element.
16 . The blanket of claim 15 , wherein the first and second bus bars comprise a metal wire.
17 . The blanket of claim 16 , wherein the metal wire is one of a plurality of braided metal wires.
18 . The blanket of claim 15 , wherein the first and second bus bars comprise a metal foil.
19 . The blanket of claim 15 , wherein the first and second bus bars comprise conductive ink.
20 . The blanket of claim 15 , wherein the first and second bus bars are coupled to the heater by sewn threads.
21 . The blanket of claim 20 , wherein the sewn threads are conductive.
22 . An electric warming blanket, comprising:
a flexible heater including a first side and a second side, at least one of the first and second sides having a surface area and a substantially uniform watt density output across the surface area when the element is electrically powered;
a first layer of water resistant material disposed over the first side of the heater, being un-adhered thereto, and forming an outer surface of the blanket when the blanket is draped over an object or a person to be warmed;
a second layer of water resistant material disposed over the second side of the heater, being un-adhered thereto, and forming an inner surface of the blanket, adjacent to the object or the person, when the blanket is draped thereover;
the first layer of water resistant material coupled to the second layer of water resistant material about a perimeter of the heater to form a substantially hermetically sealed space for the heater; and
a layer of thermal insulation disposed between the first side of the heater and the first layer of water resistant material.
23 . The blanket of claim 22 , wherein the heater comprises carbon.
24 . The blanket of claim 22 , wherein the heater comprises a nonconductive layer coated with a conductive material.
25 . The blanket of claim 24 , wherein the nonconductive layer of the heater comprises a woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
26 . The blanket of claim 24 , wherein the nonconductive layer of the heater comprises a non-woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
27 . The blanket of claim 24 , wherein the non-conductive layer of the heater comprises a non-woven cellulose material and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
28 . The blanket of claim 22 , wherein the layer of thermal insulation comprises a flexible polymeric foam.
29 . The blanket of claim 22 , wherein the layer of thermal insulation includes a plurality substantially parallel slits extending partially therethrough.
30 . The blanket of claim 22 , wherein the layer of thermal insulation includes a plurality of substantially parallel slits extending completely therethrough.
31 . The blanket of claim 22 , wherein the layer of thermal insulation comprises a high loft fibrous polymeric non-woven material.
32 . The blanket of claim 22 , wherein the layer of thermal insulation is attached to the heater.
33 . The blanket of claim 22 , wherein the layer of thermal insulation is un-attached to the heater.
34 . The blanket of claim 22 , further comprising:
a first conductive bus bar coupled to the first side of the heater and extending alongside a first lateral edge of the heater; and
a second conductive bus bar coupled to the first side of the heater and extending alongside a second lateral edge of the heater;
wherein the first lateral edge is opposite the second lateral edge;
the first and second bus bars are contained in the substantially hermetically sealed space formed by the first and second layers of water-resistant material;
the first and second bus bars are adapted for coupling to a power source for powering the heating element; and
the first and second bus bars comprise one of: a metal wire, a metal foil and a conductive ink.
35 . The blanket of claim 34 , wherein the layer of thermal insulation extends over the first and second bus bars.
36 . An electric warming blanket, comprising:
a flexible heater including a first lateral edge and a second lateral edge opposite the first lateral edge;
a flexible shell enveloping the flexible heater, to form a substantially hermetically sealed space for the flexible heater, and extending beyond both the first and second lateral edges of the heater;
at least one first stiffening member supported by the flexible shell beyond the first lateral edge of the heater; and
at least one second stiffening member supported by the flexible shell beyond the second lateral edges of the heater.
37 . The blanket of claim 36 , wherein the flexible heater comprises a conductive fabric.
38 . The blanket of claim 36 , wherein the flexible heater comprises carbon.
39 . The blanket of claim 36 , wherein the flexible heater comprises a nonconductive layer coated with a conductive material.
40 . The blanket of claim 39 , wherein the nonconductive layer of the heater comprises a woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
41 . The blanket of claim 39 , wherein the nonconductive layer of the heater comprises a non-woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
42 . The blanket of claim 39 , wherein the non-conductive layer of the heater comprises a non-woven cellulose material and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
43 . The blanket of claim 36 , wherein each of the at least one first and the at least one second stiffening members comprise a polymeric material.
44 . The blanket of claim 36 , wherein each of the at least one first and the at least one second stiffening members extend along a length of the heater.
45 . The blanket of claim 44 , wherein each of the at least one first and the at least one second stiffening members comprise a pair of stiffening members.
46 . The blanket of claim 45 , wherein each pair of more than one pair of stiffening members is separated by a flexible gap along the length of the heater.
47 . The blanket of claim 36 , wherein the flexible shell comprises a first layer of water resistant material coupled to a second layer of water resistant material about a perimeter of the heater and about at least a portion of a perimeter of each of the at least one first stiffening member and the at least one second stiffening member.
48 . The blanket of claim 36 , further comprising:
a first conductive bus bar coupled to the heater and extending alongside the first lateral edge of the heater; and
a second conductive bus bar coupled to the heater and extending alongside a second lateral edge of the heater;
wherein the first and second bus bars are contained in the substantially hermetically sealed space formed by the flexible shell;
the first and second bus bars are adapted for coupling to a power source for powering the heater; and
the first and second bus bars comprise one of: a metal wire, a metal foil and a conductive ink.
49 . An electric warming blanket, comprising:
a flexible heater including a first lateral edge and a second lateral edge opposite the first lateral edge;
a first conductive bus bar coupled to the heater and extending alongside the first lateral edge of the heater;
a second conductive bus bar coupled to the heater and extending alongside the second lateral edge of the heater;
a temperature sensor coupled to the heater at a location between the first and second bus bars where the heater will be in conductive contact with a body when the blanket is draped over the body;
the temperature sensor providing input to a temperature controller, the controller adapted to control a supply of power to the first and second bus bars, the supply of power being based on a sensed temperature from the temperature sensor; and
at least one super over-temperature sensor coupled to the heater between the first and second bus bars;
the at least one super over-temperature sensor adapted to interrupt the supply of power to the first and second bus bars when a temperature sensed by the at least one super over-temperature sensor exceeds a prescribed temperature.
50 . The blanket of claim 49 , further comprising an over-temperature sensor coupled to the heater in proximity to the temperature sensor, the over-temperature sensor providing redundant input to the temperature controller.
51 . The blanket of claim 49 , further comprising a flexible shell enveloping the flexible heater, to form a substantially hermetically sealed space for the flexible heater, the first and second bus bars, the temperature sensor and the at least one super-over temperature sensor.
52 . The blanket of claim 49 , wherein the at least one super-over temperature sensor comprises a plurality of super over-temperature sensors wired in series with one another.
53 . The blanket of claim 52 , wherein a first portion of the plurality of super over-temperature sensors is disposed in proximity to the first bus bar and a second portion of the plurality of super over-temperature sensors is disposed in proximity to the second bus bar.
54 . The blanket of claim 49 , wherein the at least one super-over temperature sensor is disposed in proximity to one of the first and second bus bars.
55 . The blanket of claim 49 , wherein the heater comprises carbon.
56 . The blanket of claim 49 , wherein the heater comprises a nonconductive layer coated with a conductive material.
57 . The blanket of claim 56 , wherein the nonconductive layer of the heater comprises a woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
58 . The blanket of claim 56 , wherein the nonconductive layer of the heater comprises a non-woven polymer and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
59 . The blanket of claim 56 , wherein the non-conductive layer of the heater comprises a non-woven cellulose material and the conductive material comprises one of: polypyrrole, carbonized ink and metalized ink.
60 . The blanket of claim 49 , wherein the at least one super over-temperature sensor interrupts the supply of power by opening a power circuit that couples the supply of power to the first and second bus bars.
61 . The blanket of claim 49 , wherein the at least one super over-temperature sensor interrupts the supply of power by increasing in resistance.
62 . The blanket of claim 49 , wherein the at least one super over-temperature sensor is part of an over-temperature circuit adapted to indirectly interrupt the supply of power.
63 . The blanket of claim 49 , wherein the at least one super over-temperature sensor is part of a power circuit which is adapted to directly interrupt the supply of power.
64 . The blanket of claim 49 , wherein the prescribed temperature is in a range from approximately 45° C. to approximately 60° C.
65 . The blanket of claim 49 , wherein the first and second bus bars comprise one of: a metal wire, a metal foil and a conductive ink.