JP2528860Y2 - Premix gas burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a premixed gas burner having a burner element on one side of a burner duct.

[Conventional technology]

In recent years, due to environmental problems such as air pollution, gas fuels such as city gas and LPG, which have extremely low levels of harmful components in combustion gas, have tended to be used extensively in industry, and boilers using gas burners are increasing. .

As the boiler gas burner, a blast type burner, particularly a premix type surface combustion burner, has been widely used.
This type of premixed surface combustion burner is of a type in which premixed gas is ejected through a burner element having a large number of small-diameter vent holes to generate a large number of micro flames on the surface of the burner element.

[Problems to be solved by the invention]

By the way, the combustion chamber of a boiler, for example, a multi-tube once-through boiler, has various shapes such as a circular shape and a rectangular shape depending on the arrangement of water pipes. An appropriate form according to the type is selected.

However, in the premixed gas burner, as shown in FIG.
A plate-like burner element 2 extending long along the longitudinal direction of the burner duct 1 is attached. From the upper end side of the burner duct 1, the combustion air supplied by a blower or the like and the burner duct 1 project inside the burner duct 1. The fuel gas from the gas supply pipe 3 attached to the fuel gas is mixed to form a premixed gas in the burner duct 1, and the premixed gas is ejected from the burner element 2. Points are recognized.

The formation of the premixed gas in the premixed gas burner is based on the combustion airflow flowing in the burner duct 1.
Since the fuel gas is ejected from the large number of ejection holes 4 of the gas supply pipe 3, mixing is mainly performed by diffusion of the fuel gas in the combustion air, and the mixing state of the two is insufficient. When the premixed gas is supplied to the burner element 2 in such a non-uniform mixing state, the premixed gas is ejected from each of a number of small holes (not shown) formed on the entire surface of the burner element 2. The mixed air flows have different degrees of mixing, and the combustion flame formed in the burner element 2 is also unbalanced, so that uniform combustion is not performed such that unburned premixed air remains.

In particular, when the burner element 2 is extended in parallel with the main flow of the premixed gas as described above, the mixing state changes at the upper end and the lower end of the burner element 2, and the combustion flame is reduced. The deviation of the combustion state becomes even more remarkable.

In order to solve this kind of problem, some attempts have been made to dispose a turbulence promoter such as punching metal on the entire surface of the premixed gas flow path upstream of the burner element 2 (that is, inside the burner duct 1). However, according to this method, the pressure loss is large, the pressure of the premixed gas supplied to the burner element 2 is reduced, and the combustion surface load is reduced.
If the supply pressure of combustion air or fuel gas is increased in order to prevent this, the problem arises that it is too costly to increase the capacity of the supply means such as a blower.

[Means for solving the problem]

The present invention has been made in view of the above problems and has been made in order to solve the above problem.The present invention has a burner element on one side of a burner duct, and supplies a fuel gas from a gas supply pipe inserted into the burner duct, and the inside of the burner duct. A premixed gas is formed by mixing with the combustion air flowing through the burner element, and the premixed gas is ejected from the burner element to burn the premixed gas. The cross-sectional area of the flow path is gradually reduced from the upstream side to the downstream side, the gas supply pipe is provided at a position downstream of the throttle member, and a fuel gas ejection hole of the gas supply pipe is formed downstream of the throttle member. It is characterized in that it is arranged at a position facing a swirl flow generation region of the combustion air.

[Action]

According to the premixed gas burner according to the present invention, the throttle member is disposed in the burner duct to form a vortex generation region of the combustion air on the downstream side, and a gas supply pipe is formed toward the vortex generation region. By ejecting the fuel gas from the ejection hole, the mixing of the combustion air and the fuel gas is promoted by the vortex entrainment effect.

〔Example〕

1 to 3 show an embodiment of a premixed gas burner according to the present invention. In these drawings, a plate-shaped burner element 2 extending long in the longitudinal direction of the burner duct 1 is attached to one side surface of a lower end side of a substantially straight tubular burner duct 1, and supplied from an upper end side of the burner duct 1 by a blower or the like. The combustion air to be mixed with the fuel gas from the gas supply pipe 3 attached to the burner duct 1 so as to protrude into the burner duct 1 to form a premixed gas in the burner duct 1. The gas is ejected from the burner element 2.

A throttle member 10 is disposed on the upstream side of the gas supply pipe 3 protruding into the burner duct 1, and the fuel gas ejection hole 4 of the gas supply pipe 3 is placed in the vortex generation region A in the burner duct 1 by the throttle member 10. In the illustrated embodiment, the aperture member has a substantially inverted V-shaped cross section.
The burner duct 1 is arranged and fixed on the upstream side of the gas supply pipe 3 in the burner duct 1, and the ridge portion 11 is directed toward the upper end side of the burner duct 1. The width of the throttle member 10 is substantially equal to the inner width of the burner duct 1, and the thickness (ie, the throttle member)
10) is larger than the diameter of the gas supply pipe 3 and is approximately の of the depth inside the burner duct 1. That is, by disposing the throttle member 10 in the burner duct 1, the flow path cross-sectional area of this part of the burner duct 1 is reduced toward the downstream side (gradual reduction from the upstream side to the downstream side). On the downstream side of the throttle member 10, the flow path cross-sectional area of the burner duct 1 is reduced to approximately 1/2 or less.

For this reason, the combustion air supplied from the upper end of the burner duct 1 is supplied to the burner duct 1 at the portion where the throttle member 10 is provided.
Are divided in two directions in the depth direction, and the narrowed cross-sectional areas increase the flow velocity and generate a high-speed airflow. At the boundary surface of the high-speed airflow, a vortex is generated due to the flow velocity difference.
Therefore, a vortex generation region A is formed downstream of the throttle member 10.

The above-mentioned gas supply pipe 3 is protruded in the width direction of the burner duct 1 in the central portion on the downstream side of the throttle member 10 in the burner duct 1, and the gas supply pipe 3 is formed with a large number of ejection holes 4. is there. These ejection holes 4 are formed in one or more rows on both sides in the depth direction of the burner duct 1 in the gas supply pipe 3, and the ejection holes 4 are arranged at positions facing the vortex generation region A, The jet direction of the fuel gas from each jet hole 4 depends on the vortex generation region A.
Is set to Therefore, the fuel gas is ejected from the ejection hole 4 toward the vortex generation region A.

The fuel gas entrained in the vortex in the vortex generation area A is further taken into the high-speed air flow and is strongly stirred, and the flow velocity of the high-speed air flow is reduced by an appropriate distance downstream from the gas supply pipe 3. In the region B where the fuel gas starts to decrease, a moderate turbulence is generated, and the fuel gas and the combustion air are further strongly stirred. That is, the high-speed airflow forms a premixed gas in which the fuel gas and the combustion air are uniformly stirred and mixed.

Therefore, the premixed gas that is uniformly stirred and mixed is supplied to the burner element 2, so that the premixed gas ejected from each of the small holes of the burner element 2 becomes a uniformly mixed premixed gas. A uniform combustion flame is formed on the surface of the burner element 2, and all the premixed gas burns completely.

FIGS. 4 and 5 show another embodiment of the present invention. Instead of the throttle member 10 having a substantially V-shaped cross section, a flat throttle member 10 'is attached to the burner duct 1 by being inclined. One side edge 13 of the throttle member 10 'is used as a flow path for fuel air. In this case, the gas supply pipe 3
It is disposed in a direction along one side edge 13 of the aperture member 10 ′,
The ejection holes 4 are arranged on one side of the gas supply pipe 3. In this embodiment, the main functions and effects are the same as those of the above-described embodiment, and therefore the description thereof will be omitted.

[Effect of the invention]

As described above, according to the premixed gas burner according to the present invention, the throttle member is disposed in the burner duct, and the vortex formed on the downstream side agitates the fuel gas supplied from the gas supply pipe so as to be involved.・ Because it is possible to mix and form an extremely uniform pre-mixed gas, the flame formed on the burner element is uniform over the entire surface, and complete fuel can be obtained without generating incompletely burned portions. .

Further, the pressure loss caused by providing the throttle member in the burner duct is slight, and it is not necessary to increase the capacity of the combustion air supply fan as in the related art. This effect is particularly remarkable when the throttle member is gradually reduced in cross-sectional area of the flow passage in the burner duct from the upstream side to the downstream side.

In addition, the premixed gas burner according to the present invention only has to provide a throttle member for uniform premixed gas formation.
It can be manufactured at very low cost.

[Brief description of the drawings]

1 to 3 show an embodiment of a premixed gas burner according to the present invention. FIG. 1 is a side view, FIG. 2 is an enlarged plan view of a main part, and FIG. FIG. 4 is an enlarged side view of a main part for describing functions. 4 and 5 show another embodiment of the premixed gas burner according to the present invention. FIG. 4 is a side view, and FIG. 5 is an enlarged plan view of a main part. FIG. 6 is a side view showing an example of a conventional premixed gas burner. DESCRIPTION OF SYMBOLS 1 ... Burner duct 2 ... Burner element 3 ... Gas supply pipe 4 ... Ejection hole 10 ... Throttle member 10 '... Throttle member 11 ... Twill wire part 12 ... End edges 13 ... One side edge A …… vortex current generation area B …… area

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Showa 58-10530 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A burner element 2 is provided on one side of a burner duct 1. A fuel gas is supplied from a gas supply pipe 3 inserted into the burner duct 1, and is mixed with combustion air flowing in the burner duct 1 to be premixed. In a premixed gas burner of the type in which air is formed and this premixed gas is ejected from the burner element 2 and burned, a throttle member 10 is provided in the burner duct 1, and the cross-sectional area of the flow passage of the burner duct 1 is set to the The gas supply pipe 3 is provided at a position downstream of the throttle member 10, and the fuel gas ejection hole 4 of the gas supply pipe 3 is formed downstream of the throttle member 10. A premixed gas burner, which is disposed at a position facing a swirl generation region A of combustion air.