Patent Application
20190353402
The present invention relates generally to a temperature control system, and more particularly to a temperature control system of a gas-fired water heater that involves a circulation pump for continuously pumping return water through a return water pipe into a heat exchanger.
Referring to
Referring to
The known water heaters suffer at least the following drawbacks:
(1) The heat exchanger 90 has to bear a relatively high thermal stress because a great temperature difference exists between a water inlet port (connected with the cold water pipe 91) and the water outlet port (connected to the hot water pipe 92) of the heat exchanger 90.
(2) Because of thermal inertia and thermal impact, the service life of the heat exchanger 90 is shortened.
(3) Due to latent heat of the heat exchanger 90, there are severe issues of excessively high and low temperatures.
(4) Loading applied to the mixing valve 93 and the 2-way valve 96 is heavy for they have to constantly adjust to accommodate different flow rates.
Thus, it is necessary for improvement of the known temperature control mechanism of water heaters.
An objective of the present invention is to provide a temperature control system of a gas-fired water heater that involves a circulation pump for continuously pumping water to return through a return water pipe back into a heat exchanger in order to constantly keep the temperature of the heat exchangers the same as a set temperature.
To achieve the above objective, the present invention comprises a heat exchanger, a cold water pipe, a hot water pipe, and a circulation pump, wherein the heat exchanger heats and converts cold water into hot water. The cold water pipe is connected to one side of the heat exchanger to supply cold water into the heat exchanger. The hot water pipe is connected to another side of the heat exchanger to output hot water generated by the heat exchanger. The circulation pump is mounted to a water return pipe. The water return pipe has two ends that are respectively connected to the hot water pipe and the heat exchanger to direct and return hot water from the hot water pipe back into the heat exchanger.
The present invention is provided with a circulation pump that takes the place of the traditionally used mixing valve and adjustment valve. When a hot water faucet is opened to activate a combustion operation of the gas-fired water heater, the circulation pump is constantly kept in operation to pump and return the hot water from the hot water pipe through the water return pipe, as returned water, back into the heat exchanger. At the same time, the cold water pipe supplies cold water into the heat exchanger so that the returned hot water and the cold water are mixed in the heat exchanger for preheating for the purpose of reaching a set temperature and making temperature control stable, without excessively high or excessively low temperature. The temperature of the heat exchanger can be always kept at the same level as the set temperature. The heat exchanger does not cause any issue of latent heat.
When the hot water faucet is closed to thus shut down the combustion operation of the gas-fired water heater, the circulation pump 40 is periodically set into operation at a fixed or variable interval in order to generate a water flow that helps reduce generation and accumulation of scale.
The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.
Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.
The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.
Referring to
The heat exchanger 10 is operable to heat and convert cold water into hot water with an operation principle that is commonly known and will be not repeated herein.
The cold water pipe 20 is connected to one side of the heat exchanger 10 to supply cold water to the heat exchanger 10.
The hot water pipe 30 is connected to another side of the heat exchanger 10 to output hot water generated by the heat exchanger 10.
The circulation pump 40 is mounted to a water return pipe 50. The water return pipe 50 has two ends respectively connected to the hot water pipe 30 and the heat exchanger 10 to direct hot water from the hot water pipe 30 back to the heat exchanger 10.
In an embodiment, the heat exchanger 10 comprises a water tank. The water tank has a capacity that is less than or equal to 10 gallons, this covering heat exchangers of the instantaneous heating type (which has no water storage at all) or fire tube type and hybrid type (which have a minor amount of water storage). For water storage greater than such a range may not achieve a uniform temperature inside the tank and may not be capable of effective control of temperature.
In an embodiment, the water return pipe 50 is connected to the hot water pipe 30 and the heat exchanger 10 to form an internal circulation. The connection between the water return pipe 50 and the heat exchanger 10 forms an inlet port of return water, which is not set at the same location as that of an inlet port of cold water formed of the connection between the cold water pipe 20 and the heat exchanger 10.
In an embodiment, the heat exchanger 10 is combined with a combustion blower 60, wherein the combustion blower 60 is connected to a fuel gas pipe 61 and the fuel gas pipe 61 comprises a fuel gas valve 62, for supplying fuel gas to the heat exchanger 10 to serve as a combustion heat source.
The above provides a description to the components of the present invention and the assembly thereof. Examples of use, features, and advantages of the present invention will be illustrated below.
The present invention is applied to a circulation pump 40 to take the place of the traditionally used mixing value and adjustment valve. When a hot water faucet is opened to cause activation of a gas-fired water heater for combustion, the circulation pump 40 is constantly supplied with electrical power to continuously drive hot water from the hot water pipe 30, through the water return pipe 50, back into the heat exchanger 10 so as to achieve continuous circulation of the return water, and at the same time, the cold water pipe supplies cold water into the heat exchanger, so that the cold water is mixed with the return water in the heat exchanger 10 for pre-heating to reach a set temperature (for example a temperature of hot water being set at 50° C.). Temperature control in this way is stable so that no excessively high or excessively low temperature may occur. The temperature of the heat exchanger 10 can be constantly kept at the set temperature and no latent heat may occur in the heat exchanger 10.
When the hot water faucet is closed to have the combustion operation of the gas-fired water heater shut down, the circulation pump 40 is periodically set into operation at a fixed or variable interval so that flowing water helps reduce accumulation and generation of scale.
The present invention possesses at least the following advantages:
(1) The temperature of the heat exchanger 10 is constantly kept the same as the set temperature.
(2) The heat exchanger 10 has no temperature hysteresis.
(3) The heat exchanger 10 has no latent heat so that the temperature at a hot water outlet is steady without excessively high or excessively low temperature thereby helping prevent burning caused by the latent heat of the heat exchanger 10.
(4) The circulation pump 40 is kept in operation during a water heating operation and is set into operation periodically at a fixed or variable interval in a standby period of the heater. As such, the flowing water, when moving in the heat exchanger 10, causes a water flow that helps reduce generation and accumulation of scale.
(5) The heat exchanger 10 has low thermal inertial and low thermal impact so that the service life can be extended.
(6) No mixing valve and adjustment valve are required so that the number of components can be reduced.
The following table provides a comparison of difference between the present invention and the conventional water heaters shown in
It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.
While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the claims of the present invention.
