System and method for controlling temperature of a liquid residing within a tank

• US 7,672,751 B2
• Filed: 03/27/2007
• Issued: 03/02/2010
• Est. Priority Date: 11/15/2001
• Status: Expired due to Fees

• Current Assignee: A. O. Smith Corporation
• Original Assignee: A. O. Smith Corporation
• Inventors: Patterson, Wade C., Phillips, Terry G.
• Primary Examiner(s): Bahta; Kidest
• Application Number:
  US11/691,723
• Publication Number:
  US 20070191994A1
• Time in Patent Office: 1,071 Days
• Field of Search: 700/282, 700/299, 700/17, 700/29, 700/300, 700/206, 419/483, 419/490, 371/561, 432/36, 432/44
• US Class Current: 700/206
• CPC Class Codes: F24D 17/0031 with accumulation of the heated water
• CPC Class Codes: F24H 15/14 Cleaning; Sterilising; Preventing contamination by bacteria or microorganisms, e.g. by replacing fluid in tanks or conduits
• CPC Class Codes: F24H 15/172 Scheduling based on user demand, e.g. determining starting point of heating
• CPC Class Codes: F24H 15/174 Supplying heated water with desired temperature or desired range of temperature
• CPC Class Codes: F24H 15/223 in the water storage tank
• CPC Class Codes: F24H 15/269 Time, e.g. hour or date
• CPC Class Codes: F24H 15/281 Input from user
• CPC Class Codes: F24H 15/37 of electric heaters
• CPC Class Codes: F24H 15/395 Information to users, e.g. alarms
• CPC Class Codes: F24H 15/421 using pre-stored data
• CPC Class Codes: F24H 15/45 remotely accessible
• CPC Class Codes: F24H 15/486 using timers
• CPC Class Codes: F24H 9/2021 Storage heaters
• CPC Class Codes: F24H 9/28 characterised by the graphical user interface [GUI]
• CPC Class Codes: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/1951 with control of the working time of a temperature controlling device

Abstract

A system for controlling a temperature of a liquid residing within a tank comprises a tank, a first heating element, a first switch, a temperature-based switch, and logic. The first heating element is mounted on the tank, and the temperature-based switch is coupled to the first heating element and to the first switch. The logic is configured to control a state of the first switch based on a temperature of a liquid residing in the tank.

Claims

1. A liquid heating system, comprising:

a tank for storing a liquid;

a first heating element mounted on the tank;

a first controller configured to activate the first heating element if a temperature of the liquid within a first region of the tank falls below a threshold; and

a second controller configured to enable or disable the first controller by controlling, based on a temperature of the liquid, whether electrical power is delivered to the first controller.

2. The system of claim 1, further comprising a second heating element mounted on the tank, wherein the second controller is configured to activate the second heating element if a temperature of a liquid within a second region of the tank falls below a threshold.

3. The system of claim 1, wherein the first controller comprises a temperature-based switch configured to control an activation state of the first heating element.

4. The system of claim 3, wherein the second controller comprises a temperature sensor and is configured to control whether the electrical power is delivered to the temperature-based switch based on the temperature sensor.

5. The system of claim 1, wherein the first controller comprises a first switch configured to control, based on the temperature of the liquid within the first region, whether electrical power is delivered to the first heating element.

6. The system of claim 5, wherein the second controller comprises a second switch coupled to the first switch.

7. A method for retrofitting an existing liquid heating system with a new controller, the existing liquid heating system having a first controller for controlling a first heating element mounted on a tank and a second controller for controlling a second heating element mounted on the tank, the first and second controllers mounted on the tank, the second controller having a temperature-based switch for controlling, based on a temperature of a liquid within the tank, whether electrical power is provided to the second heating element, the method comprising the steps of:

mounting the new controller on the tank; and

coupling the new controller to the second controller such that a switch within the new controller controls whether electrical power is delivered to the temperature-based switch.

8. The method of claim 7, further comprising the step of coupling the new controller to the first heating element.

9. The method of claim 8, further comprising the step of removing the first controller from the tank.