JP4458298B2 - Stove burner - Google Patents

Description

  The present invention relates to a stove burner capable of adjusting the heating power over a wide range from a strong fire to a hot fire.

  Conventionally, as a stove burner of this type, a large number of upper and lower two-stage flame holes are provided on the circumferential surface of the burner head with circumferential intervals, and different paths are provided to the upper and lower flame holes. In addition, an air-fuel mixture having an excess air ratio (primary air amount / theoretical air amount) of less than 1 is supplied, and the total area of the lower flame holes is smaller than the total area of the upper flame holes (for example, Patent Document 1). According to this burner, it is possible to vary the heating power over a wide range from a strong fire state in which combustion is performed in both the upper flame hole and the lower flame hole to a fire condition when combustion is performed only in the lower flame hole.

  By the way, if the upper and lower two-stage flame holes are provided, the secondary air supplied to the upper flame hole will be insufficient and will tend to be. Therefore, in the above-described conventional example, the upper flame hole is arranged with a position shifted in the circumferential direction with respect to the lower flame hole so that secondary air is supplied to the upper flame hole through the gap between the lower flame holes from below. ing. However, even in this case, it is difficult to supply a sufficient amount of secondary air to the upper flame hole, and the flame of the upper flame hole tends to elongate upward in search of secondary air, and the flame length tends to be long.

  Here, if the flame touches the bottom of the cooking container on the virtues before the completion of the combustion reaction, CO is generated due to incomplete combustion. Therefore, in the above-described conventional example in which the flame length of the upper flame hole tends to be long, it is necessary to increase the vertical distance between the burner head and the cooking vessel, and it becomes difficult to improve the thermal efficiency. Yes.

It is also conceivable to widen the gap between the lower flame holes so that a sufficient amount of secondary air can be supplied to the upper flame holes. However, in this case, the outer diameter of the burner head is increased, and the central portion of the bottom surface of the cooking container cannot be heated, resulting in poor heat distribution.
Japanese Patent No. 3782587

  In view of the above, the present invention can prevent an increase in the flame length of the upper flame hole without increasing the outer diameter of the burner head, thereby improving the thermal efficiency without deteriorating the heat distribution. The challenge is to provide a stove burner.

The present invention, on the outer peripheral surface of the burner head, upper and lower stages of the burner port is provided number at intervals each circumferential, respectively excess air ratio in the upper fire hole and the lower burner ports on each different route In the stove burner in which the total area of the lower flame hole is smaller than the total area of the upper flame hole, the excess air ratio of the air-fuel mixture supplied to the upper flame hole is supplied to the lower flame hole. It is characterized by being larger than the excess air ratio of the air-fuel mixture.

  According to the present invention, since the excess air ratio of the air-fuel mixture supplied to the upper flame hole is large, even if the gap between the lower flame holes is narrow and the supply of secondary air to the upper flame hole is restricted, the upper flame is limited. The hole flame length is shortened. Therefore, it is not necessary to increase the outer diameter of the burner head, the heat distribution can be improved, and the vertical distance between the burner head and the cooking container can be shortened, improving the thermal efficiency.

  Here, when the excess air ratio of the air-fuel mixture increases, the flame is easily lifted. Therefore, in order to perform stable combustion without lifting the air-fuel mixture at the lower flame hole, the excess air ratio of the air-fuel mixture supplied to the lower flame hole is set to a value smaller than 0.7, preferably 0.5 to 0.6. Should. On the other hand, even if the supply of secondary air to the upper flame hole is restricted, the excess air ratio of the air-fuel mixture supplied to the upper flame hole is 0.7 or more in order to shorten the flame length of the upper flame hole. It is desirable to make it. In this case, if there is no lower flame hole, the flame of the upper flame hole is lifted, but in the present invention, the flame of the upper flame hole is not lifted by the flame holding effect by the flame of the lower flame hole.

  With reference to FIG. 1, 1 is a stove body, 2 is a top plate that covers the top surface of the stove body 1, and 3 is a burner for the stove. The top plate 2 is provided with a burner opening 2a. On the top plate 2, five virtues not shown so as to surround the burner opening 2 a are placed. Then, the cooking container placed on the five virtues is heated by the burner 3.

The burner 3 includes a burner body 4 inserted through the burner opening 2 a and a burner head 5 on the burner body 4. The outer peripheral surface of the burner head 5, as shown in FIG. 2, upper and lower stages of the burner port 6U, 6L are provided a number at intervals each circumferential direction. Here, the upper flame holes 6U are not provided at a plurality of locations in the circumferential direction that match the plurality of five virtue claws in order to prevent the flame from touching the five virtue claws and causing incomplete combustion. Accordingly, the number of the lower flame holes 6L is slightly larger than the number of the upper flame holes 6U. However, the area of each lower flame hole 6L is much smaller than the area of each upper flame hole 6U, so the total area of the lower flame hole 6L is smaller than the total area of the upper flame hole 6U. Further, an air-fuel mixture (mixed gas of fuel gas and primary air) having an excess air ratio of less than 1 is supplied to each of the upper flame hole 6U and the lower flame hole 6L through different paths as will be described later.

The burner body 4 is composed of an inner and outer triple cylinder including an outer cylinder 41, an intermediate cylinder 42, and an inner cylinder 43. Further, the burner head 5 is fitted into an annular lower head member 51 having a cylindrical portion 51a fitted to the intermediate cylinder 42 of the burner body 4 on the inner periphery and an inner cylinder 43 of the burner body 4 on the inner periphery. It is comprised with the cyclic | annular upper head member 52 which hung the cylindrical part 52a which unites. On the upper surface outer peripheral portion of the lower head member 51, an annular projection which is on the head member 52 is seated is erected, the groove comprising an upper stage burner ports 6U is formed on the protrusion. Further, on the lower surface outer peripheral portion of the lower head member 51, an annular projection which is seated on the upper end of the outer tubular body 41 of the burner body 4 is provided vertically, the grooves become lower stage burner ports 6L are formed in the projections .

The burner 3 further includes a first mixing pipe 7U for the upper flame hole 6U communicating with the space between the intermediate cylinder 42 and the inner cylinder 43 of the burner body 4, and an intermediate cylinder 41 between the burner body 4 and the outer cylinder 41. And a second mixing pipe 7L for the lower flame hole 6L communicating with the space between the cylindrical body 42. The first and second nozzles 8U and 8L are arranged so as to face the upstream ends of the first and second mixing tubes 7U and 7L. Then, in the first mixing pipe 7U, the space between the intermediate cylinder 42 and the inner cylinder 43 of the burner body 4 and the space between the lower head member 51 and the upper head member 52, the mixture is supplied to the upper flame hole 6U. A gas mixture supply path to be supplied is configured. Further, the air-fuel mixture in the lower flame holes 6L in the space between the space and the outer cylinder 41 and the lower head member 51 between the second mixing tube 7 L, outer tubular body 41 of the burner body 4 and the intermediate cylinder 42 An air-fuel mixture supply path for supplying gas is configured. As a result, it is possible to adjust the heating power over a wide range from a strong fire state in which combustion is performed in both the upper stage flame hole 6U and the lower stage flame hole 6L to a closed fire state if combustion is performed only in the lower stage flame hole 6L.

  The outer cylinder 41 of the burner body 4 is provided with a skirt portion 41a extending downward from the outer periphery of the upper end portion. And the cover ring 9 which covers the burner opening 2a of the top plate 2 is extrapolated to the skirt portion 41a so that the infiltration of the spilled juice from the burner opening 2a can be prevented by the cover ring 9.

  Further, the burner 3 includes a spark plug 10 that ignites the lower flame hole 6L, and a thermoelectric that detects the flame of the lower flame hole 6L at a position opposite to the circumferential direction of the burner head 5 from the position where the spark plug 10 is disposed. A pair of flame detection elements 11 is attached. The burner 3 is further provided with a pan bottom temperature sensor 12 that is positioned in the inner circumferential space of the burner surrounded by the burner head 5 and detects the temperature of the cooking container.

  By the way, when the upper and lower two-stage flame holes 6U and 6L are provided, the supply of secondary air from below to the upper flame hole 6U is hindered by the flame of the lower flame hole 6L. Therefore, in the present embodiment, the upper flame hole 6U is arranged with its position shifted in the circumferential direction with respect to the lower flame hole 6L, and through the gap between the lower flame holes 6L and 6L adjacent in the circumferential direction, the upper flame hole 6U is viewed from below. Secondary air is supplied.

  Here, if the outer diameter of the burner head 5 is increased, the gap between the lower flame holes 6L and 6L can be widened to sufficiently supply secondary air to the upper flame hole 6U. However, if the outer diameter of the burner head 5 is increased, the central portion of the bottom surface of the cooking container cannot be heated, the heat distribution becomes worse, and the small diameter cooking container cannot be efficiently heated. On the other hand, if the outer diameter of the burner head 5 is reduced, the gap between the lower flame holes 6L, 6L becomes narrow, and the supply of secondary air to the upper flame hole 6U becomes insufficient. As a result, the flame in the upper flame hole 6U seeks secondary air and extends upward, and the flame length becomes longer. Therefore, it is necessary to increase the vertical distance between the burner head 5 and the cooking vessel so that the flame of the upper flame hole 6U does not touch the bottom surface of the cooking vessel and incompletely burn, and the thermal efficiency is increased. descend.

  Therefore, in this embodiment, the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is made larger than the excess air ratio of the air-fuel mixture supplied to the lower flame hole 6L. According to this, even if the gap between the lower flame holes 6L and 6L is narrow and the supply of secondary air to the upper flame hole 6U is restricted, the flame length of the upper flame hole 6U has a large excess air ratio of the air-fuel mixture. To be shorter. Therefore, even if the outer diameter of the burner head 5 is reduced, the flame length of the upper flame hole 6U can be shortened. As a result, the heat distribution can be improved and the vertical distance between the burner head 5 and the cooking container can be shortened, and the thermal efficiency is improved.

  In order to confirm the above effects, the burner of this embodiment with the burner head 5 having an outer diameter of 67 mm is burned with high heating power (calorific value 5.2 kw), and a 20 cm diameter pan containing water is heated. A test was conducted to measure the thermal efficiency and the CO concentration in the combustion exhaust. In the test, 13A was used as the fuel gas. Here, if the excess air ratio of the air-fuel mixture is increased to 0.7 or more, the flame generally tends to lift. In order to perform stable combustion without lifting the air-fuel mixture in the lower flame hole 6L, the excess air ratio of the air-fuel mixture supplied to the lower flame hole 6L is set to a value smaller than 0.7, preferably 0.5 to 0.6. Should. Therefore, in the test, the excess air ratio of the air-fuel mixture supplied to the lower flame hole 6L is kept constant at 0.55, and the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is set to 0.67, 0.7, and 0.88. Instead, the thermal efficiency and the CO concentration in the combustion exhaust were measured.

  FIG. 3 shows the test results when the vertical distance between the upper end of the burner head 5 and the pan bottom is 26 mm. When the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is 0.67, the flame of the upper flame hole 6U touches the bottom of the pan and burns incompletely, and the CO concentration reaches an allowable value (0.1%). It will be as high as 0.14%. On the other hand, if the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is set to 0.7, the CO concentration decreases to 0.08%, which is below the allowable value. This is because the flame length of the upper flame hole 6U is shortened and the flame does not touch the bottom of the pan. Further, when the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is increased to 0.88, which is close to the limit of natural air supply, the CO concentration is further reduced and the thermal efficiency is improved.

  If there is no lower flame hole 6L, a lift of the flame occurs if the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is 0.7 or more. However, in this embodiment, the flame lift of the upper flame hole 6U did not occur. This is because lift is suppressed by the flame holding effect by the flame of the lower flame hole 6L that stably burns.

  FIG. 4 shows the vertical distance between the burner head 5 and the bottom of the pan necessary for making the CO concentration 0.08% and the thermal efficiency at this time. When the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is 0.67, the CO concentration does not decrease to 0.08% unless the vertical distance between the burner head 5 and the pan bottom is 28 mm. . On the other hand, if the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is set to 0.7, the CO concentration becomes 0. 0 even if the vertical distance between the burner head 5 and the pan bottom is relatively short as 26 mm. Decrease to 08%. And thermal efficiency improves by shortening the up-down direction distance between the burner head 5 and a pan bottom. If the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U is 0.88, the CO concentration is 0.08% even if the vertical distance between the burner head 5 and the pan bottom is shortened to 20 mm. The thermal efficiency is further improved.

  As apparent from the above test results, the diameter of the burner head 5 is reduced to improve the heat distribution, and the distance between the burner head 5 and the bottom of the pan is shortened by shortening the flame of the upper flame hole 6U. In order to improve the thermal efficiency, it is desirable to set the excess air ratio of the air-fuel mixture supplied to the upper flame hole 6U to 0.7 or more.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to this. For example, in the above embodiment, the burner head 5 is composed of the upper and lower head members 51 and 52, but the two head members 51 and 52 may be integrated to form an upper flame hole by perforation. Further, the burner head 5 can be integrated with the burner body 4, and the upper and lower flame holes can be formed by perforation.

Sectional drawing of the burner of embodiment of this invention. The perspective view of the burner of embodiment. The graph which shows the relationship between CO density | concentration and thermal efficiency, and the air excess rate of the air-fuel | gaseous mixture supplied to an upper stage flame hole. The graph which shows the relationship between the distance between the burner head required for making CO concentration into a predetermined value, a pan bottom, thermal efficiency, and the excess air ratio of the air-fuel mixture supplied to an upper stage flame hole.

Explanation of symbols

  3. Burner for stove, 5 ... Burner head, 6U ... Upper flame hole, 6L ... Lower flame hole, 7U ... Mixing tube for upper flame hole, 7L ... Mixing tube for lower flame hole.

Claims (2)

Outside peripheral surface of the burner head, upper and lower stages of the burner port is provided number at intervals each circumferential, upper burner ports and the lower burner ports and the respective excess air ratio in each alternative route is less than 1 While supplying the air-fuel mixture, in the stove burner in which the total area of the lower flame hole is smaller than the total area of the upper flame hole,
A stove burner characterized in that the excess air ratio of the air-fuel mixture supplied to the upper flame hole is made larger than the excess air ratio of the air-fuel mixture supplied to the lower flame hole.   The excess air ratio of the air-fuel mixture supplied to the lower flame hole is made smaller than 0.7, and the excess air ratio of the air-fuel mixture supplied to the upper flame hole is made 0.7 or more. Stove burner.

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