Gas water heater and safety control method and system therefor

Patent metadata

Field	Value
Publication number	US-10775078-B2
Application number	US-201916289616-A
Country	US
Kind code	B2
Filing date	Feb 28, 2019
Priority date	Aug 31, 2016
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

The present invention provides a gas water heater, and a safety control method and system therefor. The system includes: an exhaust fan; a rotational speed detecting unit, configured to detect a rotational speed of the exhaust fan; a power obtaining unit, configured to obtain a set value for output power of the exhaust fan; a rotational speed difference obtaining unit, configured to obtain an actual value of the rotational speed and a reference value of the rotational speed according to the set value for the output power, and to calculate a difference between them; and an exhaust control unit, connected to the exhaust fan, the rotational speed detecting unit, the rotational speed difference obtaining unit and the power obtaining unit respectively, configured to correct a predetermined wind pressure curve graph at an air outlet of the exhaust fan according to the difference.

First claim

What is claimed is:

1. A safety control system for a gas water heater, comprising:
an exhaust fan, configured to exhaust waste gas generated when the gas water heater burns gas;
a rotational speed detecting unit, configured to detect a rotational speed of the exhaust fan;
a power obtaining unit, configured to obtain a set value for output power of the exhaust fan;
a rotational speed difference obtaining unit, configured to obtain an actual value of the rotational speed and a reference value of the rotational speed according to the set value for the output power, and to calculate a difference between the actual value of the rotational speed and the reference value of the rotational speed; and
an exhaust control unit, connected to the exhaust fan, the rotational speed detecting unit, the rotational speed difference obtaining unit and the power obtaining unit respectively, and configured to correct a predetermined wind pressure curve graph at an air outlet of the exhaust fan according to the difference, to determine a wind pressure situation at the air outlet according to the rotational speed, a corrected wind pressure curve graph and the set value for the output power, and to adjust the set value for the output power according to the wind pressure situation, wherein the predetermined wind pressure curve graph comprises a plurality of curves each indicating a predetermined rotational speed as a function of the set value for the output power.

2. The safety control system according to claim 1 , wherein the exhaust control unit is configured to correct the predetermined wind pressure curve at an air outlet of the exhaust fan according to the difference by making the corrected wind pressure curve graph comprise plurality of curves each indicating a sum of the difference and the predetermined rotational speed as a function of the set value for the output power.

3. The safety control system according to claim 2 , wherein the exhaust control unit is configured to determine a wind pressure situation at the air outlet according to the rotational speed, a corrected wind pressure curve graph and the set value for the output power and to adjust the set value for the output power according to the wind pressure situation by performing following acts:
controlling the set value for the output power to be reduced by a first predetermined value when the exhaust control unit determines that the wind pressure situation is a low wind pressure situation;
controlling the set value for the output power to keep unchanged when the exhaust control unit determines that the wind pressure situation is a medium wind pressure situation; and
controlling the set value for the output power to be increased by a second predetermined value when the exhaust control unit determines that the wind pressure situation is a high wind pressure situation.

4. The safety control system according to claim 1 , further comprising a system control unit configured to perform a mutual communication with the exhaust control unit, wherein
the exhaust control unit is configured to send a shut-off signal to the system control unit such that the system control unit controls the gas water heater to shut off according to the shut-off signal, when the exhaust control unit determines that the wind pressure situation is an extreme high wind pressure situation or the rotational speed is higher than a rotational speed threshold.

5. The safety control system according to claim 4 , further comprising:
a water supply unit, connected to the system control unit; and
a temperature obtaining unit, connected with the system control unit, configured to obtain a set temperature for output water of the gas water heater and a cold water temperature of the gas water heater,
wherein, the system control unit is configured to calculate a total heat required by the gas water heater according to a water supply quantity of the water supply unit, the set temperature for the output water and the cold water temperature, and to obtain a current control instruction and an initial set value for the output power according to the total heat.

6. The safety control system according to claim 5 , further comprising:
a gas unit, connected to the system control unit and provided with a proportional valve, wherein
the system control unit is configured to control the gas unit by controlling the proportional valve according to the current control instruction.

7. The safety control system according to claim 1 , wherein the gas water heater is a forced exhaust type gas water heater.

8. A gas water heater, comprising:
a safety control system for a gas water heater, comprising:
an exhaust fan, configured to exhaust waste gas generated when the gas water heater burns gas;
a rotational speed detecting unit, configured to detect a rotational speed of the exhaust fan;
a power obtaining unit, configured to obtain a set value for output power of the exhaust fan;
a rotational speed difference obtaining unit, configured to obtain an actual value of the rotational speed and a reference value of the rotational speed according to the set value for the output power, and to calculate a difference between the actual value of the rotational speed and the reference value of the rotational speed; and
an exhaust control unit, connected to the exhaust fan, the rotational speed detecting unit, the rotational speed difference obtaining unit and the power obtaining unit respectively, and configured to correct a predetermined wind pressure curve graph at an air outlet of the exhaust fan according to the difference, to determine a wind pressure situation at the air outlet according to the rotational speed, a corrected wind pressure curve graph and the set value for the output power, and to adjust the set value for the output power according to the wind pressure situation, wherein the predetermined wind pressure curve graph comprises a plurality of curves each indicating a predetermined rotational speed as a function of the set value for the output power.

9. A safety control method for a gas water heater, comprising:
obtaining a set value for output power of an exhaust fan in the gas water heater and a reference value of a rotational speed of the exhaust fan corresponding to the set value for the output power;
obtaining an actual value of the rotational speed according to the set value for the output power, and calculating a difference between the actual value of the rotational speed and the reference value of the rotational speed;
correcting a predetermined wind pressure curve graph at an air outlet of the exhaust fan according to the difference, wherein the predetermined wind pressure curve graph comprises a plurality of curves each indicating a predetermined rotational speed as a function of the set value for the output power;
detecting the rotational speed of the exhaust fan; and
determining a wind pressure situation at an air outlet of the exhaust fan according to the rotational speed, a corrected wind pressure curve graph and the set value for the output power, and adjusting the set value for the output power according to the wind pressure situation.

10. The safety control method according to claim 9 , wherein correcting a predetermined wind pressure curve graph at an air outlet of the exhaust fan according to the difference comprises:
making the corrected wind pressure curve graph comprise a plurality of curves each indicating a sum of the difference and the predetermined rotational speed as a function of the set value for the output power.

11. The safety control method according to claim 10 , wherein determining a wind pressure situation at an air outlet of the exhaust fan according to the rotati

Assignees

• Wuhu Midea Kitchen & Bath Appliances Mfg Co Ltd
• Midea Group Co Ltd

Inventors

• Xue Chengzhi
• Dai Xianfeng
• Shou Liping
• Liang Zefeng
• Liang Guorong

Classifications

• F04D27/00

  Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids · CPC title

• F23N3/082

  using electronic means · CPC title

• F23N3/085

  using electrical or electromechanical means · CPC title

• F24H9/205 Primary

  Closing the energy supply · CPC title

• F24H9/2035

  using fluid fuel · CPC title