Gas boiler including output adjusting device, and method of adjusting output of gas boiler

A gas boiler and a method of adjusting output of the gas boiler by adjusting mixture ratio of air and gas for combustion in proportion to an output value of the boiler, and continuously changing the mixture regardless of the boiler output. The gas boiler includes a ventilator, a gas valve, a burner, a combustion chamber, a heat exchanger, and an exhaust gas hood. The inlet of the ventilator includes an output adjusting device having an air inlet; an air adjustment valve; a gas outlet; a gas adjustment valve that adjusts the gas passing through the gas outlet; and a valve driving unit that drives the air adjustment valve and the gas adjustment valve. Output of the burner is continuously adjusted by adjusting distance between the air adjustment valve and the gas adjustment valve, and distance between the air inlet and the gas outlet.

TECHNICAL FIELD

The present invention relates to a gas boiler including an output adjusting device, and method of adjusting output of gas boiler, and more particularly, to a gas boiler including an output adjusting device, and method of adjusting output of gas boiler which may simplify a structure of the output adjusting device for uniformly adjusting a mixture ratio of air and gas for combustion in proportion to an output value of the boiler, and may accurately adjust an output of the boiler even when a set output value of the boiler is in a low output range.

BACKGROUND ART

A conventional gas boiler includes a ventilator10that introduces external air and supplies air necessary for combustion, a gas valve20that adjusts supply of gas for combustion that is mixed with the air introduced by the ventilator10, a burner30that combusts a mixture of the gas for combustion and the air supplied by the ventilator10, a combustion chamber40in which the combustion of the burner30occurs, a heat exchanger50in which a heat exchange between combustion gas generated by the burner30and hot water occurs, and an exhaust gas hood60through which the combustion gas passing through the heat exchanger50is discharged.

In the conventional gas boiler constructed as described above, when an output of a boiler is changed, it means that an output of the burner30is changed. In order to change the output of the burner30, the amount of air and the amount of gas have to be changed in proportion to the output.

However, the conventional gas boiler has problems in that since the ventilator10that introduces external air and the gas valve20that adjusts the amount of gas for combustion which is supplied are separately disposed and an additional unit for controlling the amount of gas supplied by the gas valve20in proportion to the amount of air supplied by the ventilator10has to be provided, a structure of a device is complex and it is difficult to accurately control a mixture ratio of the air and the gas for combustion according to a preset output of the boiler.

A method of changing the amount of air which is a method of changing the number of rotations of the ventilator10involves rotating the ventilator10at a high speed when a high output of the boiler is necessary and rotating the ventilator10at a low speed when a low output of the boiler is necessary.

In this case, as the ventilator10is changed from a high speed rotation to a low speed rotation and the number of rotations is reduced, a wind pressure of air supplied by the ventilator10is also reduced.

In this case, when the wind pressure is reduced to a value less than or equal to a predetermined value, although the ventilator10rotates at a low speed, the ventilator10does not supply air.

Accordingly, there is a limitation in reducing an output of the boiler using only a method of reducing the number of rotations of the ventilator10, reducing the amount of air which is supplied, and proportionately reducing the amount of gas for combustion supplied by the gas valve20in the conventional gas boiler. Accordingly, a range of a turn-down ratio (TDR) of the boiler may not be increased.

The TDR refers to a ‘ratio of a maximum amount of gas consumption to a minimum amount of gas consumption’ in a gas combustion device in which the amount of gas is variably adjusted. The TDR is limited by the minimum amount of gas consumption for maintaining a stable flame. In a gas boiler, as the TDR increases, user convenience during heating and hot water supply may increase, a deviation in temperature control may decrease, and the durability of a device may be improved.

DISCLOSURE

Technical Problem

The present invention is directed to providing a gas boiler including an output adjusting device which may simplify a structure of the output adjusting device for uniformly adjusting a mixture ratio of air and gas for combustion in proportion to an output value of the boiler.

The present invention is also directed to providing a gas boiler including an output adjusting device, and method of adjusting output of gas boiler which may increase a turn-down ratio (TDR) by accurately controlling an output of the boiler by continuously changing the amount of a mixture of air and gas for combustion which are supplied even when the output of the boiler is a low output as well as a high output.

Technical Solution

One aspect of the present invention provides a gas boiler including: a ventilator that introduces external air and supplies air necessary for combustion; a gas valve that adjusts supply of gas for combustion that is mixed with the air; a burner that combusts a mixture of the gas and the air supplied by the ventilator; a combustion chamber in which the combustion of the burner occurs; a heat exchanger that absorbs combustion heat of combustion gas generated by the burner; and an exhaust gas hood through which the combustion gas passing through the heat exchanger is discharged, the gas for combustion passing through the gas valve being supplied to an inlet of the ventilator, wherein the inlet of the ventilator is provided with an output adjusting device including: an air inlet through which the external air is supplied to the ventilator; an air adjustment valve that adjusts an amount of the air supplied through the air inlet; a gas outlet through which the gas passing through the gas valve is discharged; a gas adjustment valve that adjusts an amount of the gas for combustion passing through the gas outlet; and a valve driving unit that drives the air adjustment valve and the gas adjustment valve, wherein the air adjustment valve and the gas adjustment valve are integrally formed with each other, and an output of the burner is continuously adjusted by adjusting a distance between the air adjustment valve and the gas adjustment valve and between the air inlet and the gas outlet.

A distance between the air adjustment valve and the air inlet and a distance between the gas adjustment valve and the gas outlet may be changed equally.

The air adjustment valve and the gas adjustment valve may be integrally operated by the same valve driving unit, to continuously adjust amounts of the air and the gas for combustion which are supplied.

The air adjustment valve and the gas adjustment valve may be coupled in concentric circular shapes to a valve movable shaft, and the air inlet and the gas outlet may be provided in concentric cylindrical shapes to be opened and closed during reciprocations of the air adjustment valve and the gas adjustment valve.

The gas valve and the gas outlet may be provided on an axis of the valve movable shaft, and the air adjustment valve and the air inlet may be provided around outer surfaces of the gas valve and the gas outlet.

A position where the gas valve contacts the gas outlet may be lower in terms of height than a position where the air adjustment valve contacts the air inlet, so that the gas for combustion discharged to the gas outlet is mixed with the supplied air in a mixing chamber in the ventilator without leaking to the air inlet.

Another aspect of the present invention provides a method of adjusting of gas boiler including: setting an output value of a boiler; comparing the set output value with a limit output value; and when the set output value is greater than or equal to the limit output value, changing an output of the boiler by changing a number of rotations of a ventilator, and when the set output value is less than the limit output value, adjusting a flow rate of a fluid in an output adjusting device in response to the set output value.

The adjusting a flow rate of a fluid in an output adjusting device may include adjusting the flow rate of a fluid in a state where the number of rotations of the ventilator corresponding to the limit output value is maintained.

Advantageous Effects

According to gas boiler including output adjusting device, and method adjusting output of gas boiler of the present invention, since an air adjustment valve and a gas adjustment valve are integrally provided at an inlet of a ventilator and degrees by which the air adjustment valve and the gas adjustment valve are opened are equally adjusted by the same valve driving unit, a structure of the output adjusting device may be simplified, and a mixture ratio of air and gas for combustion may be uniformly controlled in proportion to an output of a burner.

Also, according to the present invention, since an output may be accurately controlled by adjusting a flow rate in the output adjusting device even when a set output of a boiler is in a low output range, a turn-down ratio (TDR) may be increased, and the performance of the boiler may be improved.

MODES OF THE INVENTION

FIG. 2is a perspective view illustrating an outer appearance of a gas boiler including an output adjusting device, according to an embodiment of the present invention.

Referring toFIG. 2, the gas boiler includes an output adjusting device100that uniformly adjusts a mixture ratio of air and gas for combustion in proportion of a set output of a boiler, a ventilator200that is integrally connected to the output adjusting device100and supplies a mixture of the air and the gas for combustion to a burner (not shown), a combustion chamber300in which the burner is mounted and combustion occurs, a heat exchanger400including a sensible heat exchanger410that absorbs sensible heat of a combustion product generated in the combustion chamber300and a latent heat exchanger420that absorbs latent heat of vapor included in the combustion product on which a heat exchange has been performed by the sensible heat exchanger410, and an exhaust gas hood500through which combustion gas passing through the heat exchanger400is discharged to the outside.

FIG. 3is a perspective view illustrating the output adjusting device ofFIG. 2.FIGS. 4 and 5are cut-away perspective views illustrating an output adjustment unit constituting the output adjusting device ofFIG. 3, whereinFIG. 4illustrates a state where a valve is closed andFIG. 5illustrates a state where the valve is opened.

The output adjusting device100for adjusting a flow rate of a mixture of the air and the gas for combustion in proportion to a set output value in a low output range where an output value of a boiler is less than a predetermined value includes a housing130on both sides of which an air inlet pipe110and a gas inlet pipe120are provided and in which the air and the gas for combustion are mixed, an upper cover140that is coupled to the housing130, and a valve driving unit150that is provided on the upper cover140and supplies power for reciprocating an air adjustment valve112and a gas adjustment valve122.

A gas valve (not shown) that cuts off supply of the gas for combustion is provided on the gas inlet pipe120. When the gas valve is opened, the gas for combustion passing through the gas valve is supplied into an inlet of the ventilator200through the gas inlet pipe120.

The valve driving unit150which is a common driving source for integrally driving the air adjustment valve112and the gas adjustment valve122according to a set output signal of the boiler may be a bidirectional motor.

An output adjustment unit100aincluding the housing130and elements disposed in the housing130, from among the elements of the output adjusting device100, is coupled to the inlet of the ventilator200and adjusts the amounts of the external air and the gas for combustion which are supplied.

An outer appearance of the output adjustment unit100aincludes the housing130on both sides of which a gas inlet pipe120through which the gas for combustion is introduced and an air inlet pipe110through which the external air is introduced are provided, and a valve fixture135that is coupled to an upper portion of the housing130and on a central portion of which a guide unit136for guiding a vertical movement of a valve movable shaft160driven by the valve driving unit150is provided.

An air inlet114that is connected to the air inlet pipe110and acts as a path through which the introduced air is supplied to the inlet of the ventilator200, and a gas outlet124that acts as a path through which the gas for combustion introduced through the gas inlet pipe120when the gas valve is opened is supplied to the inlet of the ventilator200are provided in the housing130.

The air inlet114and the gas outlet124have cylindrical shapes whose tops are opened in directions ofFIGS. 4 and 5. The air inlet114is provided around an outer surface of the gas outlet124, and a mixing chamber170in which the air and the gas for combustion are mixed is provided in a space between the outer surface of the gas outlet124and an inner surface of the air inlet114, to communicate with the inlet of the ventilator200disposed under the mixing chamber170.

The gas adjustment valve122and the air adjustment valve112are disposed over the gas outlet124and the air inlet114and are integrally coupled in concentric circular shapes to the valve movable shaft160. As the gas adjustment valve122and the air adjustment valve112vertically move in accordance with a vertical movement of the valve movable shaft160due to an operation of the valve driving unit150, the gas outlet124and the air inlet114are opened and closed.

The gas adjustment valve122and the gas outlet124are provided on an axis of the valve movable shaft160, and the air adjustment valve112and the air inlet114are provided around outer surfaces of the gas adjustment valve122and the gas outlet124.

An upper end of the gas outlet124is formed to be lower than an upper end of the air inlet114, and a lower end of the gas adjustment valve122is formed to be lower than a lower end of the air adjustment valve112. Accordingly, when the gas adjustment valve122and the air adjustment valve112are opened to mix the air and the gas for combustion, the gas for combustion discharged to the gas outlet124may smoothly flow into the mixing chamber170without leaking to the air inlet114.

A spring162is disposed between the air adjustment valve112and the valve fixture135. Since the spring162applies an elastic force to press the air adjustment valve112and the gas adjustment valve122toward the air inlet114and the gas outlet124, the flow of a fluid may be blocked in a state where the air adjustment valve112and the gas adjustment valve122are closed.

Referring toFIG. 5, when the valve movable shaft160is moved upward by the valve driving unit150, the air adjustment valve112and the gas adjustment valve122integrally coupled to the valve movable shaft160are also moved upward. In this case, a distance L1between the gas adjustment valve122and the gas outlet124and a distance L2between the air adjustment valve112and the air inlet114are changed equally.

As such, since the air adjustment valve112and the gas adjustment valve122are integrally provided on the valve movable shaft160, and the air adjustment valve112and the gas adjustment valve122are simultaneously reciprocated by the same valve driving unit150to adjust the amounts of the air and the gas for combustion which are supplied, a structure of the output adjusting device100may be simplified, and a mixture ratio of the air and the gas for combustion may be continuously uniformly adjusted in proportion to a set output of the boiler.

FIG. 6is a graph illustrating a relationship between the number of rotations of the ventilator and an output of the boiler of the gas boiler, according to an embodiment of the present invention.

The gas boiler constructed as described above adjusts an output of the boiler by adjusting the amount of air which is supplied by changing the number of rotations of the ventilator200in proportion to a set output value in a high output range where an output value of the boiler which is set by a user is greater than or equal to a limit output value P1, and adjusts a flow rate of the air and the gas for combustion in the output adjusting device100in response to a set output value in a state where the number of rotations R1of the ventilator200which corresponds to the limit output value P1is maintained in a low output range where the output value of the boiler which is set by the user is less than the limit output value P1.

Here, the ‘limit output value P1’ refers to a boundary value between a high output and a low output. The limit output value P1may be set to an output value (or more) corresponding to the number of rotations of the ventilator200at a time when, assuming that the number of rotations of the ventilator200is reduced from a high speed to a low speed and thus a wind pressure is reduced, the amount of air supplied by the ventilator200becomes zero.

As such, when a set output value of the boiler is in a high output range, the set output value may be responded by adjusting the number of rotations of the ventilator200, and when the set output value is in a low output range, the set output value may be responded by adjusting a flow rate in the output adjusting device100in a state where the number of rotations of the ventilator200is maintained as the number of rotations R1. Accordingly, an output of the boiler may be continuously accurately controlled over entire ranges ranging from a high output range to a low output range, and thus a range of a turn-down ratio (TDR) may be increased.

As such, according to the present invention, a limitation in adjusting an output of the boiler due to a decrease in a wind pressure in a low output range when only a method of changing the number of rotations of the ventilator200is used in the low output range as well as a high output range may be solved.

An output adjustment method of the boiler constructed as described above will be explained.FIG. 7is a flowchart illustrating a method of adjusting of gas boiler, according to an embodiment of the present invention.

An output value of the boiler is set in accordance with a heating load or a hot water load to be set by the user (S10). A control unit (not shown) included in the boiler compares the set output value with a limit output value P1(S20).

When it is determined that the set output value of the boiler is greater than or equal to the limit output value P1, the control unit determines that the set output value is in a high output range and adjusts an output of the boiler by adjusting the number of rotations of the ventilator200according to the set output value of the boiler in a state where the output adjusting device100is opened to mix air and gas for combustion at a predetermined mixture ratio and supply a mixture of the air and the gas for combustion (S30).

When it is determined that the output value of the boiler which is set by the user is less than the limit output value P1, the control unit determines that the set output value is in a low output range and controls to maintain the number of rotations R1of the ventilator200which corresponds to the limit output value P1(S40), and adjusts the amounts of the air and the gas for combustion which are supplied by controlling an operation of the valve driving unit150of the output adjusting device100in proportion to the set output value (S50).

As such, according to the method of adjusting output of gas boiler of the present invention, since a method of adjusting a flow rate of a mixture in the output adjusting device100is used in a state where the number of rotations of the ventilator is maintained, unlike a conventional method of changing the number of rotations of the ventilator when a set output value of the boiler is in a low output range, the set output value even in the low output range may be continuously accurately controlled.