Heater control
First Claim
1. A control system for controlling parallel heater elements comprising:
- a plurality of electrical heater elements;
a plurality of temperature sensors associated with a plurality of the heater elements, the temperature sensors effective to generate temperature signals;
at least one temperature controller effective to generate a control signal based on at least one temperature signal;
an alternating current power supply connected to the electrical heater elements through a power transmission system;
a zero detection circuit effective to generate a signal when the voltage of the alternating current power supply passes through ground potential;
a firing controller that will block electrical power to a heater element, starting when a zero detection signal is detected an ending when another zero detection signal is detected, for a fraction of the alternating current cycles in a time period, the fraction being a function of the control signal;
a remote modem in the proximity of the heater elements effective to convert the temperature signals to signals transmitted through the power transmission system and to detect a control signal transmitted through the power transmission system; and
a master modem effective to convert the control signal to a signal transmitted through the power transmission system and to detect temperature signals transmitted through the power transmission system.
1 Assignment
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Accused Products
Abstract
A method and apparatus are provided for controlling parallel heater elements, the method including the steps of: providing a plurality of electrical heater elements; generating a plurality of temperature signals associated with a plurality of the heater elements; generating a control signal based on one or more temperature signals; providing an alternating current power supply connected to the electrical heater elements through a power transmission system; generating a signal when the voltage of the alternating current power supply passes through ground potential; blocking electrical power to a heater element starting when a zero detection signal is detected an ending when another zero detection signal is detected, for a fraction of the alternating current cycles in a time period, the fraction being a function of the control signal; and transmitting temperature control signals through the power transmission system.
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Citations
20 Claims
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1. A control system for controlling parallel heater elements comprising:
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a plurality of electrical heater elements; a plurality of temperature sensors associated with a plurality of the heater elements, the temperature sensors effective to generate temperature signals; at least one temperature controller effective to generate a control signal based on at least one temperature signal; an alternating current power supply connected to the electrical heater elements through a power transmission system; a zero detection circuit effective to generate a signal when the voltage of the alternating current power supply passes through ground potential; a firing controller that will block electrical power to a heater element, starting when a zero detection signal is detected an ending when another zero detection signal is detected, for a fraction of the alternating current cycles in a time period, the fraction being a function of the control signal; a remote modem in the proximity of the heater elements effective to convert the temperature signals to signals transmitted through the power transmission system and to detect a control signal transmitted through the power transmission system; and a master modem effective to convert the control signal to a signal transmitted through the power transmission system and to detect temperature signals transmitted through the power transmission system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for controlling parallel heater elements, the method comprising the steps of:
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providing a plurality of electrical heater elements; generating a plurality of temperature signals associated with a plurality of the heater elements; generating a control signal based on one or more temperature signals; providing an alternating current power supply connected to the electrical heater elements through a power transmission system; generating a signal when the voltage of the alternating current power supply passes through ground potential; blocking electrical power to a heater element starting when a zero detection signal is detected an ending when another zero detection signal is detected, for a fraction of the alternating current cycles in a time period, the fraction being a function of the control signal; and transmitting control signals through the power transmission system. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification