Method and appts. for detecting dry fire condition in water heater

A technology for water heaters and heating elements, applied in lighting and heating equipment, temperature control using analog comparators, water heaters, etc.

Inactive Publication Date: 2004-05-26
AOS HLDG CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Typically, a dry burn will result in the heating element being destroyed or burned out in less than 1 minute

Method used

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  • Method and appts. for detecting dry fire condition in water heater
  • Method and appts. for detecting dry fire condition in water heater
  • Method and appts. for detecting dry fire condition in water heater

Examples

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Embodiment Construction

[0031] As noted above, the use of a proportional band temperature controller in a water heater with a resistive heating element has the unexpected advantage of heating the water in the water heater to a preselected set point temperature more than the same temperature controller using a prior art mechanical temperature controller. It takes less electricity to heat an equal volume of water to the same set point temperature in a water heater.

[0032] An exemplary proportional band temperature controller is an electronic device that includes: a water temperature sensing device (thermistor); a temperature set point device (varistor); a gated thyristor to switch electrical power to a resistor a heating element; and logic circuitry for controlling the thyristors in response to signals from the water temperature sensing device and the temperature set point device. The logic circuit receives voltage inputs from the water temperature sensing device and the temperature set point device,...

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PUM

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Abstract

A water heater having a water tank and multiple electric resistance heating elements extending into the water tank for heating water in the tank. The water heater includes a proportional band temperature controller for conducting electric power to the electric resistance heating elements in bursts. Each burst of electric power is followed by a period during which the temperature controller does not conduct power to the electric resistance heating element. In one embodiment, each burst of electrical power lasts for about 95 % or less of a cycle comprised of one burst of electric power followed by the period during which the temperature controller does not conduct electric power. Further, activation of the heating elements by the controller is carried out in a sequential or other timed or controlled fashion to permit uniform heating of the water in the tank.

Description

[0001] related application [0002] The present invention is a continuation of US Patent No. 09 / 361,825 filed August 17,1999. field of invention [0003] The present invention mainly relates to electric water heaters. More specifically, the present invention relates to methods and apparatus for determining whether a heating element of a water heater is surrounded by water. Background technique [0004] Storage-type water heaters typically include: a permanently enclosed tank; a cylindrical casing coaxial with and radially away from the tank to form an annulus between the outer wall of the tank and the inner wall of the casing; and thermal insulation at least in the annulus part of the tank to provide insulation to the tank. Tanks have various accessories such as water inlets, water outlets and drains. In addition, the water heater also has a water heating and temperature control system. The water heating and temperature control system includes resistance heating elements...

Claims

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Application Information

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IPC IPC(8): F24H1/20F24H9/20G05D23/19H05B1/02H05B3/82
CPCF24H1/202G05D23/1909F24H9/2021F24H9/2007H05B1/0283H05B3/82F24H15/37F24H15/395F24H15/144F24H15/225F24H15/407F24H15/414F24H15/254F24H15/174F24H15/242F24H15/281
Inventor 肯尼思·A·布雷登鲍
Owner AOS HLDG CO
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