Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
252 words
An electrical circuit which comprises (1) a three phase power source; (2) a first elongate electrical self-regulating heater which comprises (a) a first elongate electrical connection means having a near end and a far end; (b) a second elongate electrical connection means having a near end and a far end; and (c) a plurality of electrical elements which are connected in parallel with each other between the first and second electrical connection means; (3) a second elongate electrical self-regulating heater which comprises (a) a first elongate electrical connection means having a near end and a far end; (b) a second elongate electrical connection means having a near end and a far end; and (c) a plurality of electrical elements which are connected in parallel with each other between the first and second electrical connection means; and (4) a third elongate electrical self-regulating heater which comprises (a) a first elongate electrical connection means having a near end and a far end; (b) a second elongate electrical connection means having a near end and a far end; and (c) a plurality of electrical elements which are connected in parallel with each other between the first and second electrical connection means; one end of one of the connection means of each of the first, second and third heaters being connected to the first, second or third phase of the power source, and the other ends of the other connection means of each of the heaters being connected to a different phase or to each other.
Claim 2
Dependent Claim
252 words
An electrical circuit which comprises (1) a three phase power source; (2) a first elongate electrical self-regulating heater which comprises (a) a first elongate electrical connection means having a near end and a far end; (b) a second elongate electrical connection means having a near end and a far end; and (c) a plurality of electrical elements which are connected in parallel with each other between the first and second electrical connection means; (3) a second elongate electrical self-regulating heater which comprises (a) a first elongate electrical connection means having a near end and a far end; (b) a second elongate electrical connection means having a near end and a far end; and (c) a plurality of electrical elements which are connected in parallel with each other between the first and second electrical connection means; and (4) a third elongate electrical self-regulating heater which comprises (a) a first elongate electrical connection means having a near end and a far end; (b) a second elongate electrical connection means having a near end and a far end; and (c) a plurality of electrical elements which are connected in parallel with each other between the first and second electrical connection means; one end of one of the connection means of each of the first, second and third heaters being connected to the first, second or third phase of the power source, and the other ends of the other connection means of each of the heaters being connected to a different phase or to each other.
Claim 3
Dependent Claim
94 words
A circuit according to claim 1 wherein the near end of the first connection means of the first heater is connected to the first phase of the power source, the near end of the first connection means of the second heater is connected to the second phase of the power source, the near end of the first connection means of the third heater is connected to the third phase of the power source, and the far ends of the second connection means of the first, second and third heaters are connected to each other.
Claim 4
Dependent Claim
27 words
A circuit according to claim 2 wherein the far ends of the second connection means of the heaters are connected to the neutral of the power source.
Claim 5
Dependent Claim
32 words
A circuit according to claim 2 wherein each of the first, second and third heaters comprise a plurality of electrical elements (c) which comprise a continuous strip of a PTC conductive polymer.
Claim 6
Dependent Claim
17 words
A circuit according to claim 4 wherein the first, second and third heaters have substantially identical cross-sections.
Claim 7
Dependent Claim
19 words
A circuit according to claim 2 wherein each of the first, second and third heaters is a zone heater.
Claim 8
Dependent Claim
140 words
A circuit according to claim 1 wherein the near end of the first connection means of the first heater is connected to the first phase of the power source, the near end of the first connection means of the second heater is connected to the second phase of the power source, the near end of the first connection means of the third heater is connected to the third phase of the power source, the far end of the second connection means of the first heater is connected to the second phase of the power source, the far end of the second connection means of the second heater is connected to the third phase of the power source, and the far end of the second connection means of the third heater is connected to the first phase of the power source.
Claim 9
Dependent Claim
32 words
A circuit according to claim 7 wherein each of the first, second and third heaters comprise a plurality of electrical elements (c) which comprise a continuous strip of a PTC conductive polymer.
Claim 10
Dependent Claim
17 words
A circuit according to claim 8 wherein the first, second and third heaters have substantially identical cross-sections.
Claim 11
Dependent Claim
19 words
A circuit according to claim 7 wherein each of the first, second and third heaters is a zone heater.
Claim 12
Dependent Claim
20 words
An electrical circuit according to claim 1 wherein at least one of said heaters is at least 330 feet long.
Claim 13
Dependent Claim
18 words
An electrical circuit according to claim 11 wherein each of said heaters is at least 330 feet long.
Claim 14
Dependent Claim
33 words
An electrical circuit according to claim 2, wherein the heaters are located end to end to form a heater assembly whose length is equal to the sum of the lengths of the heaters.
Claim 15
Dependent Claim
33 words
An electrical circuit according to claim 7, wherein the heaters are located end to end to form a heater assembly whose length is equal to the sum of the lengths of the heaters.
Claim 16
Dependent Claim
32 words
An electrical circuit according to claim 4 wherein in each of the heaters the plurality of electrical elements comprises an elongate element composed of a melt-extruded conductive polymer which exhibits PTC behavior.
Claim 17
Dependent Claim
22 words
An electrical circuit according to claim 15 wherein each of the heaters comprises two parallel metallic electrodes embedded in said elongate element.
Claim 18
Dependent Claim
32 words
An electrical circuit according to claim 8 wherein in each of the heaters the plurality of electrical elements comprises an elongate element composed of a melt-extruded conductive polymer which exhibits PTC behavior.
Claim 19
Dependent Claim
22 words
An electrical circuit according to claim 17 wherein each of the heaters comprises two parallel metallic electrodes embedded in said elongate element.
Claim 20
Dependent Claim
346 words
An electrical circuit which comprises (1) a three phase power source; (2) a first self-regulating heater which has a near end and a far end, which is at least 330 feet long, and which comprises first and second elongate parallel metallic electrodes embedded in an elongate strip of a melt-extruded conductive polymer exhibiting PTC behavior; (3) a second self-regulating heater which has a near end and a far end, which is at least 330 feet long, and which comprises first and second elongate parallel metallic electrodes embedded in an elongate strip of a melt-extruded conductive polymer exhibiting PTC behavior; (4) a third self-regulating heater which has a near end and a far end, which is at least 330 feet long, and which comprises first and second elongate parallel metallic electrodes embedded in an elongate strip of a melt-extruded conductive polymer exhibiting PTC behavior; the heaters being located end to end to form a heater assembly which is at least 990 feet long, the near end of the first electrode of the first heater being connected to the first phase of the power source; the near end of the first electrode of the second heater being connected to the second phase of the power source by means of a first conductor which runs the length of the first heater; the near end of the first electrode of the third heater being connected to the third phase of the power source by means of a second conductor which runs the length of the first and second heaters; and the far ends of the second electrodes of the first, second and third heaters being connected to each other at a junction point which lies at the far end of the third heater, the far end of the first heater being connected to the junction point by means of a third conductor which runs the length of the second and third heaters, and the far end of the second heater being connected to the junction point by means of a fourth conductor which runs the length of the third heater.
Claim 21
Dependent Claim
346 words
An electrical circuit which comprises (1) a three phase power source; (2) a first self-regulating heater which has a near end and a far end, which is at least 330 feet long, and which comprises first and second elongate parallel metallic electrodes embedded in an elongate strip of a melt-extruded conductive polymer exhibiting PTC behavior; (3) a second self-regulating heater which has a near end and a far end, which is at least 330 feet long, and which comprises first and second elongate parallel metallic electrodes embedded in an elongate strip of a melt-extruded conductive polymer exhibiting PTC behavior; (4) a third self-regulating heater which has a near end and a far end, which is at least 330 feet long, and which comprises first and second elongate parallel metallic electrodes embedded in an elongate strip of a melt-extruded conductive polymer exhibiting PTC behavior; the heaters being located end to end to form a heater assembly which is at least 990 feet long, the near end of the first electrode of the first heater being connected to the first phase of the power source; the near end of the first electrode of the second heater being connected to the second phase of the power source by means of a first conductor which runs the length of the first heater; the near end of the first electrode of the third heater being connected to the third phase of the power source by means of a second conductor which runs the length of the first and second heaters; and the far ends of the second electrodes of the first, second and third heaters being connected to each other at a junction point which lies at the far end of the third heater, the far end of the first heater being connected to the junction point by means of a third conductor which runs the length of the second and third heaters, and the far end of the second heater being connected to the junction point by means of a fourth conductor which runs the length of the third heater.
Claim 22
Dependent Claim
42 words
A circuit according to claim 19 which also comprises a fifth conductor which is connected to the far ends of the second electrodes of the first, second and third heaters at said junction point and to the neutral of the power supply.
Claim 23
Dependent Claim
28 words
A circuit according to claim 20 wherein the first, second, third and fourth conductors are of the same size and the fifth conductor is of a smaller size.