JP2018021681A - Premixed type gas burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that air flow rate cannot be controlled accurately since a gap between a butterfly valve through which air passes and an air passage is greatly affected by a rotational angle of the butterfly valve although a valve travel has been adjusted by the butterfly valve in the air passage conventionally.SOLUTION: An air inlet hole for sucking air into a mixing part and a gas inlet hole for sucking gas into the mixing part are provided in the mixing part for sucking air and gas, both the inlet holes are formed in a rectangular shape, and an air shutter and a gas shutter advancing from one side of a pair of mutually opposing sides of the respective inlet holes to the other side by a motor are provided.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a premixed gas burner in which a gas and air necessary for combustion of the gas are mixed in advance and supplied to a gas burner.

  In the gas burner called a premixing type, it is provided with a blower fan that blows combustion air to the gas burner upstream of the gas burner, and further, gas is mixed at a predetermined ratio into the air that is supplied to the gas burner by the blower fan, An air / gas mixture is supplied to the gas burner.

  As a gas burner device including such a gas burner and a blower fan, for example, a butterfly valve is provided in an air suction portion on the upstream side of the blower fan to switch the intake resistance, and a gas is provided downstream of the butterfly valve. A valve is provided to switch the gas passage resistance, and the butterfly valve and the gas passage valve are connected so that the resistance of the gas passage increases when the intake resistance is increased by the butterfly valve. A mechanically linked one is known (for example, see Patent Document 1).

  In this conventional type, the butterfly valve is normally fully open. However, when it is desired to burn the gas burner with a calorific value smaller than the calorific value (input) corresponding to the lower limit value of the rotational speed of the blower fan, It is possible to reduce the amount of combustion in the gas burner while narrowing the flow and reducing the amount of gas jetting and operating the rotational speed of the blower fan at a rotational speed higher than the lower limit.

JP 2014-215007 A (FIG. 1)

  In the above conventional one, the opening of the air passage is adjusted by the butterfly valve, but the distance between the butterfly valve through which the air passes and the air passage is greatly affected by the rotation angle of the butterfly valve, so the air flow rate is accurately adjusted. It is difficult to control. Further, the gas flow rate is also switched by opening and closing the gas passage opening with a valve. However, since the opening is circular, the diameter of the opening varies due to a processing error or the like, and the variation in diameter is 2. As a result, the opening area varies. For this reason, there arises a problem that it is difficult to make the mixing ratio constant especially when the opening degree is reduced.

  In view of the above problems, an object of the present invention is to provide a premixed gas burner in which the mixing ratio of air and gas does not vary even when the amount of combustion is reduced.

  In order to solve the above problems, a premixed gas burner according to the present invention is a premixed gas burner for supplying a mixture of air and gas to a burner chamber provided upstream of a burner having a flame hole, A blower fan connected to the burner chamber is provided, a mixing section is provided at the intake port of the blower fan, combustion air and gas are sucked into the mixing section, and sent from the blower fan to the burner chamber. In the above-mentioned mixture by mixing air and gas, both the air suction port for sucking ambient air into the mixing unit and the gas suction port for sucking gas into the mixing unit are formed in a rectangular shape. In addition, an air shutter and a gas shutter that advance and retreat from one side of a pair of sides facing each other to the other side of each suction port are provided. Increase or decrease And wherein the Rukoto.

  A feature of the present invention is that both the air suction port and the gas suction port are rectangular. Then, an air shutter and a gas shutter that advance and retreat from one side of a pair of sides facing each other to each other are provided, and when changing the opening degree of both the suction ports, The opening degree of both suction ports is increased or decreased by moving both shutters forward and backward. Thereby, the dispersion | variation in the opening area of each suction port can be reduced as much as possible.

  Although both the shutters may be driven individually, the air shutter and the gas shutter may be connected to each other so that both the shutters are advanced and retracted by one motor.

  The mixing portion has a hollow cylindrical outer wall, the air suction port is formed in the outer wall, and a tubular gas supply pipe is provided at a substantially central portion of the outer wall, and the peripheral surface of the gas supply pipe The combustion air sucked into the air-fuel mixture from the air suction port and the gas sucked into the air-fuel mixture from the gas supply pipe through the gas suction port are formed. It is desirable to form a partition between the air suction port and the gas suction port so as not to collide in the air-fuel mixture.

  Alternatively, the mixing portion has a hollow cylindrical outer wall, and the air suction port is formed in the outer wall, and a tubular gas supply pipe is provided at a substantially central portion of the outer wall, and the peripheral surface of the gas supply pipe The combustion air sucked into the air-fuel mixture from the air suction port and the gas sucked into the air-fuel mixture from the gas supply pipe through the gas suction port are formed. The distance between the intake port of the blower fan and the air suction port and the distance between the intake port of the blower fan and the gas suction port may be made different so as not to collide with each other in the air-fuel mixture.

  As is apparent from the above description, the present invention forms an air suction port for taking in combustion air into the blower fan and a gas suction port for taking in the gas in a rectangular shape, and the opening area of these suction ports is increased. By providing each of the shutters narrowing from one direction, the mixing ratio of air and gas in a low combustion state where the flow rate is particularly small does not vary, and a stable combustion state in the burner can be obtained.

The figure which shows the structure of one embodiment of this invention Diagram showing the outer shape of the mixing section Vertical section showing the internal structure of the mixing section IV-IV cross section Longitudinal sectional view showing the second embodiment Longitudinal sectional view showing a third embodiment

  Referring to FIG. 1, 1 is an example of a premixed gas burner according to the present invention. The inconsistent premixing gas burner 1 is incorporated in a hot water supply apparatus, and includes a plate-like gas burner 11 in which a flame is formed downward and a heat exchanger 12 connected to the lower side of the gas burner 11. . In addition, 13 is an exhaust duct and is for discharging | emitting the combustion gas which passed the heat exchanger 12 outside.

  The gas burner 11 is supplied with a gas / air mixture from above by the blower fan 2. The blower fan 2 includes a turbine inside, and the turbine is rotated by a motor 21. When the turbine rotates, a negative pressure is generated in the air inlet portion formed in the central portion, and external air and gas are sucked into the blower fan 2. The intake port of the blower fan 2 is opened above the blower fan 2, and the mixing unit 3 is attached to the intake port.

  With reference to FIGS. 2 to 4, the mixing portion 3 is provided with a cylindrical main body 34 and a gas supply pipe 35 at the center of the main body 34. The gas supply pipe 35 communicates with an opening 31 for receiving a gas supply from the outside, and a gas decompressed to an atmospheric pressure by a zero governor (not shown) is supplied to the opening 31.

  An air suction port 32 that is rectangular in the horizontal direction in the figure is formed in the upper part of the main body 34, and a gas that is rectangular in the horizontal direction in the figure is also formed in the upper part of the gas supply pipe 35. A suction port 36 is formed. Therefore, when the blower fan 2 is operated, external air is sucked into the main body 34 from the air suction port 32, and gas in the gas supply pipe 35 is sucked into the main body 34 through the gas suction port 36. . The air and gas sucked into the main body 34 are sucked into the blower fan 2, mixed and supplied to the gas burner 11. The flow rate of the air-fuel mixture supplied to the gas burner 11 is substantially proportional to the rotational speed of the blower fan 2. Therefore, if the rotational speed of the blower fan 2 is decelerated to reduce the amount of combustion in the gas burner 11 and the operation is performed at a low speed, the passage flow speeds of both the suction ports 32 and 36 become low, and it is easily affected by disturbance.

  Therefore, when the rotational speed of the blower fan 2 becomes low, the opening areas of the suction ports 32 and 36 are narrowed so that the flow velocity at the suction ports 32 and 36 can be secured.

  In order to reduce the opening area of the air suction port 32, an air shutter 33 is provided. The air shutter 33 is rotated by the motor 30. When the air shutter 33 rotates, the air suction port 32 is blocked from the lateral direction in the drawing, and the opening area is reduced.

  A gas shutter 37 is provided inside the gas suction port 36. The gas shutter 37 is connected to the air shutter 33. By rotating in conjunction with the air shutter 33, the gas suction port 36 is similarly blocked from the lateral direction in the figure, and the gas suction port 36 is thus closed. Decrease the opening area.

  In addition, before the opening degree of the air suction port 32 becomes zero, the gas suction port 36 may be adjusted to be closed in advance, and may be adjusted so as to be in a so-called air-rich state in a low combustion state. Alternatively, the low combustion state may be changed to a so-called gas rich state by adjusting the gas suction port 36 so that it is still open when the opening of the air suction port 32 becomes zero. .

  In the embodiment shown in FIG. 3, since the air suction port 32 and the gas suction port 36 are formed to face each other, the air flow sucked into the main body 34 and the gas sucked in the same manner are used. There is a concern that the flow collides with each other and disturbs each other.

  Therefore, in such a case, as shown in FIG. 5, a partition wall 38 is provided between the air suction port 32 and the gas suction port 36 so that the air flow and gas flow sucked into the main body 34 It is desirable to prevent the two from colliding with each other.

  Further, when such a partition wall 38 is not provided, as shown in FIG. 6, the distance La between the air suction port 32 and the air intake port of the blower fan 2, and the gas suction port 36 and the blower fan 2 are similarly formed. The distance Lg from the intake port may be adjusted to be different so that the air flow sucked into the main body 34 and the gas flow do not collide with each other.

  In addition, this invention is not limited to an above-described form, You may add a various change in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Premix type gas burner 2 Blower fan 3 Mixing part 11 Gas burner 12 Heat exchanger 21 Motor 32 Air suction port 33 Air shutter 34 Main body 35 Gas supply pipe 36 Gas suction port 37 Gas shutter 38 Partition

Claims (4)

  A premixed gas burner for supplying a mixture of air and gas to a burner chamber provided upstream of a burner having a flame hole, comprising a blower fan connected to the burner chamber, In the mixing portion provided in the intake port, the air and gas for combustion are sucked into the mixing portion, and the air and the gas are mixed while being sent from the blower fan to the burner chamber. An air suction port for sucking ambient air into the mixing unit and a gas suction port for sucking gas into the mixing unit are both formed in a rectangular shape, and one of a pair of sides facing each other of each suction port A premixed gas burner comprising an air shutter and a gas shutter that move forward and backward from one side to the other side, and the opening degree of both suction ports is increased and decreased by moving both the shutters forward and backward.   2. The premixed gas burner according to claim 1, wherein the air shutter and the gas shutter are connected to each other, and both shutters are advanced and retracted by one motor.   The mixing portion has a hollow cylindrical outer wall, and the air suction port is formed in the outer wall, and a tubular gas supply pipe is provided in a substantially central portion of the outer wall. Combustion air that forms a gas suction port and is sucked into the mixture from the air suction port and gas sucked into the mixture from the gas supply pipe through the gas suction port are mixed gas The premixed gas burner according to claim 1 or 2, wherein a partition wall is formed between the air suction port and the gas suction port so as not to collide with each other.   The mixing portion has a hollow cylindrical outer wall, and the air suction port is formed in the outer wall, and a tubular gas supply pipe is provided in a substantially central portion of the outer wall. Combustion air that forms a gas suction port and is sucked into the mixture from the air suction port and gas sucked into the mixture from the gas supply pipe through the gas suction port are mixed gas The distance between the intake port of the blower fan and the air suction port and the distance between the intake port of the blower fan and the gas suction port are made different from each other so as not to collide with each other. The premixed gas burner according to claim 2.

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