JPH0144964B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas combustion device that supplies combustion air to a burner using a centrifugal blower.

[Prior Art] Conventionally, this type of device discharges gas fuel to a discharge port of a scroll case of a centrifugal blower, or discharges gas fuel to the inner periphery of a fan to combine combustion air and gas fuel. were mixed and supplied to the burner.

[Problems to be Solved by the Invention] However, in the case where the gas fuel is spouted at the discharge port of the scroll case, the gas fuel jet port is downstream of the blower, so the gas fuel jet port receives positive pressure. For example, in the case of slight combustion where the supply amount of gas fuel is small, the discharge pressure of gas fuel is low, so
This had the problem of not being able to stably supply gas fuel to the burner, and also not being able to supply gas fuel uniformly to the entire burner because the gas fuel was mixed into a portion of the supplied air. .

In addition, for those that spout gas fuel at the inner circumference of the fan, the gas fuel jet nozzle is upstream of the fan, so the gas fuel jet nozzle receives negative pressure, and the amount of gas fuel supplied is small, resulting in fine combustion. However, the position where the gas fuel passes through the fan changes depending on the rotation speed of the fan, the shape of the fan, the position of the gas fuel nozzle, etc., and the gas fuel supplied to the burner changes. The problem was that the diffusion rate was unstable.

The present invention was made in view of the above circumstances, and
The purpose of this is to be able to supply uniform gas fuel to the entire burner without changing the diffusion rate of the gas fuel due to changes in fan rotation speed or fan shape, and to achieve fine combustion with a small supply amount of gas fuel. The present invention relates to a gas combustion device capable of stably supplying gas fuel even in the case of a gas combustion device.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a gas combustion apparatus having a centrifugal blower equipped with a fan for supplying combustion air to a burner and a scroll case. The technical means is that a protrusion is provided on the inner circumferential surface of the scroll case on the upstream side between the scroll case and a gas outlet for supplying gas fuel is provided directly below the protrusion.

[Function] In the present invention as described above, by providing a protrusion on the inner peripheral surface of the scroll case on the upstream side between the fan and the scroll case, the air immediately below the protrusion is sucked by the air that has passed through the protrusion. , or due to the vortex generated downstream of the protrusion by the protrusion,
A negative pressure area is created directly below the protrusion. By providing a gas jet port for supplying gas fuel to a portion directly below the protrusion where negative pressure is generated, the gas fuel is sucked by the negative pressure directly below the protrusion. Then, the gas fuel sucked by the negative pressure directly below the protrusion rides on the air flowing between the fan and the scroll case and is supplied to the burner.

[Effect of the invention] Due to the above-mentioned action, the gaseous fuel flowing out from the jet port is sucked by the negative pressure directly below the protrusion and is supplied to the burner, so it is stable even in the case of slight combustion where the amount of gaseous fuel supplied is small, for example. Gas fuel can be supplied to the burner.

Also, by discharging the gas fuel on the upstream side between the fan and the scroll case, the gas fuel is diffused throughout the air supplied to the burner, so the gas fuel is stabilized evenly throughout the burner. can be supplied.

[Example] Next, an example in which the present invention is applied to a gas water heater will be described with reference to FIG.

This gas water heater 1 includes a combustion section 3 having a heat exchange section 2, a gas supply section 4, and an electronic control circuit 5.

The combustion section 3 includes a combustion chamber 32 equipped with a surface combustion type burner 31 made of ceramic, and a centrifugal blower according to the present invention, which is attached to the upper part of the combustion chamber 32 and supplies air for combustion to the burner 31. 33
and an exhaust port 34 provided below the combustion chamber 32 to exhaust the combustion gas combusted by the burner 31. The heat exchange section 2 includes fins 21 that increase heat exchange efficiency and a water supply pipe 22, and burns water sent from upstream of the water supply pipe 22 arranged between the burner 31 and the exhaust port 34. Room 32
It exchanges heat with the exhaust gas inside and flows out as hot water.

In this embodiment, the centrifugal blower 33 is a Sirotsko fan 33a having a cylindrical shape with a width of, for example, 2 cm;
It consists of a scroll case 33b having a width of, for example, 3 cm, enclosing the fan 33a, and a motor (not shown) for driving the fan 33a.This motor is energized and controlled by an electronic control circuit 5 to control the amount of air blown. A scroll case 33b is located between the fan 33a and the scroll case 33b.
As shown in FIG. 2, a protrusion 33c is formed on the upstream side of the inner periphery of the scroll case 33b, extending over the entire widthwise area of the scroll case 33b and generating a negative pressure directly below the protrusion 33c.

The upstream surface of the protrusion 33c is perpendicular to the tangential direction of the inner circumference of the scroll case 33b, and the downstream surface is formed with a gentle slope. Further, the protrusion 33c of this embodiment has a third
As shown in the figure, the height H of the projection (in the radial direction of the scroll case 33b) is 5 mm, and the distance L between the tip of the projection 33c and the outer periphery of the fan 33a is 9 mm. Thereby, a negative pressure of approximately -8H ₂ O can be obtained directly below the protrusion 33c. This protrusion 33c is integrally molded with the scroll case 33b by aluminum die casting.

The gas supply path 4 includes a gas jet nozzle 41 that discharges gas fuel to a portion where negative pressure is generated downstream of the protrusion 33c, a gas supply pipe 42 that supplies gas fuel to the gas jet nozzle 41, and a gas jet nozzle. 41 and the gas supply pipe, and is energized.
An on-off valve (not shown) that opens and closes when no electricity is applied, a governor valve (not shown) that is provided downstream of this on-off valve and adjusts the gas flow rate, and a governor valve (not shown) that is provided downstream of this governor valve and that adjusts the amount of electricity and a gas control unit 43 equipped with a proportional control valve (not shown) whose opening ratio can be varied.

The gas ejection nozzle 41 has a second ejection port.
As shown in the figure, in this embodiment, the three ejection holes 41a are arranged so that the width is approximately the same as the width of the fan 33a.
is formed. In this way, by widening the width of the ejection port of the gas ejection nozzle 41, the fan 3
The gaseous fuel can be diffused throughout the air passing between 3a and the protrusion. Moreover, by making the ejection port of the gas ejection nozzle 41 a plurality of holes, the cost of increasing the width of the ejection port of the gas ejection nozzle 41 can be reduced, and the plurality of ejection holes 41a
By ejecting more gas fuel, the effect of efficiently diffusing the gas fuel can be obtained.

Further, the gas jet nozzle 41 is formed integrally with the scroll case 33b, as shown in FIG.
It is fitted inside the discharge port 43a of the gas control unit 43 via the screw 43b, and is fixed by a screw 43b.
In the gas ejection nozzle 41, there is an orifice 43c for adjusting the supply pressure and flow rate of gas fuel.
is installed. In this way, the gas jet nozzle 41 is formed integrally with the scroll case 33b, and the gas jet nozzle 41 and the gas control unit 43 are integrated.
By using means for connecting the gas jet nozzle 41 to the curved surface of the scroll case 33b, it is possible to easily and reliably attach the gas jet nozzle 41 to the curved surface of the scroll case 33b.

The electronic control circuit 5 includes a start switch (not shown) that is turned on when the gas water heater 1 is used, and a temperature control volume (not shown) that is operated by the user to set the temperature of water flowing out from the water supply pipe 22. , a thermocouple 51 that detects the oxygen supply state of the flame of the burner 31, a water temperature sensor 52 that is attached to the outlet of the water supply pipe 22 of the heat exchanger 2, and detects the water temperature.
1, a spark electrode 53 that makes sparks fly on the combustion surface of 1, a motor for the blower 33, and a gas control unit 43.
Performs energization control such as

The gas water heater 1 consisting of the above has a start switch.
When turned on, the fan 33a of the blower 33 rotates, sucking combustion air through the suction port 33d provided on the side of the scroll case 33b, and blowing the burner 3
Supply to 1.

At this time, due to the rotation of the fan 33a, the protrusion 33
The air supplied upstream of the fan 33a flows in the left rotation direction in FIG. 1 due to the rotation direction of the fan 33a and the scroll shape of the scroll case 33b. This air flow avoids the protrusion 33c, and the air immediately below the protrusion 33c is pulled by the air that has avoided the protrusion 33c. This generates negative pressure near the ejection hole 41a directly below the protrusion 33c.

On the other hand, at this time, since the on-off valve and the proportional control valve in the gas control unit 43 are opened, the protrusion 33c
Gas fuel flows out from the plurality of ejection holes 41a downstream of. Since this gas fuel is ejected to the negative pressure generating portion downstream of the protrusion 33c, the gas fuel is sucked into the scroll case 33b by the negative pressure.

The gas fuel sucked into the scroll case 33b is agitated by the vortex generated downstream of the protrusion 33c, and is supplied to the burner by riding on the combustion air flowing between the fan 33a and the scroll case 33b. The gas fuel is diffused throughout the air, and the gas fuel can be stably supplied evenly throughout the burner. This makes it possible to obtain a uniform air-fuel ratio throughout the burner 31, thereby preventing incomplete combustion and the like due to uneven supply of gas fuel, which is conventional.

Moreover, the gas fuel flowing out from the jet hole 41a is
Since it is attracted by the negative pressure generated directly below the protrusion 33c, gas fuel can be stably supplied to the burner 31 even in the case of slight combustion in which the amount of gas fuel supplied is small, for example.

Furthermore, in this embodiment, since the gas injection nozzle 41 fits within the width of the scroll case 33b, compared to the conventional system in which gas fuel is supplied from the suction port 33d of the scroll case 33b to the inner periphery of the fan, the gas injection nozzle 41 The vicinity of the housing portion of the blower 33 of the container 1 can be formed thin.

Modification Example In the above embodiment, the shape of the protrusion is such that the upstream side is upright and the downstream side is inclined, but the present invention is not limited to this. Other shapes may be used as long as negative pressure is generated downstream of the protrusion, such as having both downstream ends upright.

A protrusion and a spout may be provided in a part of the width of the scroll case.

The gas ejection nozzle may be provided separately from the scroll case. Further, in that case, by forming the protrusion integrally with the ejection port of the gas ejection nozzle, the present invention can be applied without making extensive modifications to the scroll case that has been used conventionally.

The protrusion may be provided separately from the scroll case and attached to the scroll case or gas supply piping.

The present invention may be applied to other gas combustion devices such as gas combustion heating devices.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a gas water heater according to the present invention;
FIG. 2 is a perspective view of a protrusion formed on the inner circumferential surface of the scroll case, and FIG. 3 is an enlarged sectional view of the gas jet nozzle. In the figure, 1... gas water heater, 33... centrifugal blower,
33a...fan, 33b...scroll case, 3
3c...Protrusion, 41...Gas ejection nozzle, 41a...Ejection hole.

Claims (1)

[Scope of Claims] 1. In a gas combustion apparatus having a centrifugal blower including a fan and a scroll case that supply combustion air to a burner, the scroll case is disposed on the upstream side between the fan and the scroll case. A gas combustion device characterized in that a protrusion is provided on an inner circumferential surface, and a gas jet port for supplying gas fuel is provided directly below the protrusion. 2. Claim 1, wherein the gas outlet is formed across the width of the fan.
Gas combustion equipment as described in Section. 3. The gas combustion device according to claim 2, wherein the gas ejection port is a plurality of holes.