JPS6373019A - Ventilating pressure detector - Google Patents

Abstract

PURPOSE:To permit the sure detection of an air pressure even when a ventilating capacity is deteriorated, by a method wherein a projection is provided on the inner circumferential surface of a fan case between a fan and the fan case while an air pressure switch is connected to a detecting hole provided on the inner circumferential surface near the projection. CONSTITUTION:Airflow, supplied to the upstream of a projection 45 by the rotation of a fan 40, flows so as to avoid the projection 45 and air-flow immediately below the projection 45, is pulled by the air which has avoided the projection 45. Accordingly, a negative pressure is generated near a gas injection port 55 immediately below the projection 45. This negative pressure is introduced from a negative pressure detecting hole 63 into the pressure chamber 65 of an air pressure switch 6 through a connecting pipe 64. In this case, the air, supplied to the upstream of the projection 45, or a positive pressure is introduced into the pressure chamber 62 of the air pressure switch 6 from a positive pressure detecting hole 60 through a connecting pipe 61. Accordingly, the air pressure switch 6 displaces a diaphragm 67 by a difference between the positive pressure and the negative pressure to the side of the pressure chamber 65, whose pressure has become low, against the energizing force of a spring 66 and closes a contact 69 by a rod 68 operating in conjunction with the diaphragm 67.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a blowing pressure detection device for a forced air gas combustion apparatus that detects blowing pressure and automatically supplies or stops fuel gas.

[Prior Art] Conventionally, in forced-air gas combustion devices, a wind pressure switch that detects the blowing pressure of a fan (hereinafter referred to as wind pressure) is applied as a safety device, and the operation of the wind pressure switch controls the supply or the supply of fuel gas. Combustion is controlled by automatically stopping the engine.

[Problems to be Solved by the Invention] However, in conventional forced air gas combustion devices, the wind pressure detection tube connected to the wind pressure switch protrudes into the air passage, which poses a problem in that the blowing IJa capacity is reduced. Ta. For this reason, in forced-feed gas combustion apparatuses having a small combustion capacity, wind pressure may not be reliably detected in the case of light winds.

SUMMARY OF THE INVENTION An object of the present invention is to provide a forced-air gas combustion apparatus that can reliably detect wind pressure even when the air-blowing capacity is reduced.

[Means for Solving the Problems] The air blowing pressure detection device of the present invention includes a fan provided in a fan case, and a protrusion provided on the inner peripheral surface of the fan case between the fan and the fan case. and a detection hole provided on the inner peripheral surface of the fan case near the protrusion;
A method of providing a wind pressure switch connected to the detection hole and detecting the air blowing pressure of the fan was adopted.

(Configuration of Actual Example) In this example, a fan provided in a fan case, and a connection between the fan and the fan case are provided on the inner circumferential surface of the fan case, and a negative pressure is a protrusion that generates a
The air pressure switch is connected to the detection hole and detects the negative pressure.

[Function] The air blowing pressure detection device of the present invention has a detection hole in the inner peripheral surface of the fan case between the fan and the fan case, so that the air passing through the inner peripheral surface of the fan case can be adjusted to 10% of the air volume. Loss becomes smaller.

In addition, by providing a protrusion on the inner peripheral surface of the fan case between the fan and the fan case, when air passes through the protrusion, a vortex is generated immediately below the protrusion, regardless of the size of the air blowing capacity. Negative pressure is generated immediately downstream of the

[Effects of the Invention] Due to the configuration and operation described above, the air blowing pressure detection device of the present invention can reliably detect wind pressure even when the air blowing ability of fans with similar air blowing capacity is reduced.

(Operations and Effects of the Embodiment) In this embodiment, by providing a protrusion on the inner peripheral surface of the fan case between the fan and the fan case, when air passes through the protrusion, immediately below the protrusion, "Shipping"
A vortex is generated regardless of the level of capacity (for example, fan rotation speed), and negative pressure is generated immediately downstream of the protrusion. By providing a detection hole connected to a wind pressure switch immediately below the protrusion where the negative pressure is generated, the detection of the negative pressure can be easily performed, so that the detection performance of the III pressure can be improved.

[Example] An example of the blowing pressure detection device of the present invention will be described based on the drawings.

Figures 1 to 3 show the first part of the blowing pressure detection device of the present invention.
1 shows a blowing pressure detection device for a forced air gas water heater to which an embodiment is applied.

The forced air gas hot water boiler A includes a blowing pressure detection device 1, a combustion section 2, a heat exchange section 3, and a gas supply path 5. The blowing pressure detection device 1 includes a centrifugal blower 4, a wind pressure switch 6, and an electronic control circuit 7.

The combustion section 2 includes a combustion chamber 22 equipped with a ceramic surface-combustion burner 21 to which combustion air is supplied by a centrifugal blower 4, and a combustion chamber 22 provided below the combustion chamber 22 to receive combustion gas combusted by the burner 21. The air outlet 23 is provided with an air outlet 23 for exhausting air.

The heat exchange section 3 includes fins 31 that increase the heat exchange rate, a water supply pipe 32, and a hot water supply pipe 33, and includes a burner 21 and an exhaust port 23.
The water placed between the two and sent from the upstream of the water supply pipe 32 is exchanged with the first gas in the combustion chamber 22 and supplied as a lagoon;
9 flows out from pipe 33.

In this embodiment, the centrifugal blower 4 of the air blowing pressure detection device 1 of the present invention includes a one-piece fan 40 having a cylindrical shape with a width of, for example, 2 cm, and an inlet 41 that accommodates the fan 40. A scroll casing 42, which is an open case of, for example, 3cn+7cm width, and a fan 40.
It consists of a motor (not shown) that drives the The motor is controlled by an electronic control circuit 7, and the rotational speed of the fan 40, that is, the amount of air blown is controlled.

As shown in FIGS. 2 and 3, a scroll casing 4 is provided on the upstream side of the inner peripheral surface 43 of the scroll casing 42 between the fan 40 and the scroll casing 42.
A protrusion 45 that generates negative pressure is formed immediately below 44 downstream of the protrusion 45 over the entire widthwise area of the protrusion 2 .

The protrusion 45 has an upstream side 46 that is connected to the scroll casing 4.
The scroll casing 47 is formed perpendicularly to the tangential direction of the inner circumference of the scroll casing 42, and the downstream side 47 is formed to be inclined at a predetermined angle with respect to the tangential direction of the inner circumference of the scroll casing 42. Also, protrusion 4
5, the height 1'' of the projection 45 (in the radial direction of the scroll casing 42) is 5 mm, as shown in FIG.
The distance between the tip ga48 and the outer circumference 49 of the fan 40 is 9
■It is provided in As a result, a negative pressure of about -8H2o can be generated directly below the protrusion 45 44 . The protrusion 45 is integrally molded with the scroll casing 42 by an aluminum die cast 1-.

The gas supply path 5 is integrated with the scroll casing 42 A! a gas jet nozzle 51 that discharges fuel gas to a portion where negative pressure is generated downstream of the protrusion 45; and a gas supply pipe 5 that supplies fuel gas to the gas jet nozzle 51.
2 and a gas control unit 53.

The gas control unit 53 is provided between the gas jet nozzle 51 and the gas supply pipe 52, and is provided on the flow side of an on-off valve (not shown) that opens and closes when energized or de-energized, and on the flow side of the on-off valve. a governor valve (not shown) for regulating the flow h1;
and a proportional control valve (f, not shown) which is provided downstream of the governor valve and whose opening ratio is variable according to the normal amount.

Three ejection passages 54 are provided at the tip of the gas ejection nozzle 51 (on the left in FIG. 3), and as shown in FIG. Three gas ejection ports 55 are formed in the. Furthermore, an orifice 56 for adjusting the supply pressure and flow rate of fuel gas is attached to the other end (left side in FIG. 3) of the gas jet nozzle 51.
is formed to have a smaller cross-sectional diameter than the cross-sectional diameter of the jetting passage 54. In other words, the orifice 5G also serves to prevent backflow of fuel gas.

The air pressure switch 6 of the air blowing pressure detection device 1 of the present invention includes a pressure chamber 62 connected via a connecting pipe 61 to a positive pressure detection hole 60 formed upstream of the protrusion 45 of the sufusing 42. A pressure chamber 65 is connected via a connecting pipe 64 to a negative pressure detection hole 63 formed in one of the three gas ejection passages 54 of the gas ejection nozzle 51 as shown in FIG.
and the pressure chambers 62, 65, and the spring 66
The contact point 69 is opened and closed by a rod 68 interlocking with a diaphragm 67 having a diaphragm 67 arranged on its back.

The electronic control circuit 7 of the blowing pressure detection device 1 of the present invention includes a wind pressure switch 6, gas) when the easy boiler A is used.
A start switch (U shown in the figure) that turns to N, a temperature control volume (not shown) that is operated according to the name of use and sets the temperature of water flowing out from the hot water pipe 33, and a thermocouple that detects the oxygen supply state of the flame of the burner 21. 71, the burner 21 at the time of ignition according to the input from the water temperature sensor 72, etc., which is attached to the outflow part of the hot water supply pipe 33 of the heat exchange section 3 and detects the water temperature.
Spark electrode 73 that blows sparks on the combustion surface of the centrifugal feeder 1
! Controls energization and de-energization of the full 4 motor, gas control iQ:t unit 53, etc.

The operation of this embodiment will be explained based on FIGS. 1 to 3.

In the gas water heater A, when the start switch is turned on, the fan 40 of the centrifugal blower 4 rotates, and the scroll casing 4
Combustion air is supplied to the burner 21 from the intake port 41 of No. 2.

At this time, the air supplied upstream of the protrusion 45 by the rotation of the fan 40 flows in the left rotation direction in FIG. 1 due to the rotation direction of the fan 40 and the swirl shape of the scroll casing 42. This air flow avoids the protrusion 45, and the air directly below the protrusion 44 is pulled by the air that has avoided the protrusion 45. As a result, a negative pressure is generated near the gas outlet 55 directly below the protrusion 45 .

This negative pressure is introduced from the negative pressure detection hole 63 into the pressure chamber 65 of the wind pressure switch 6 via the connecting pipe 64.

At this time, the air, that is, positive pressure, supplied upstream of the protrusion 45 is introduced from the positive pressure detection hole 60 into the pressure chamber 62 of the wind pressure switch 6 via the connecting pipe 61. Therefore, the wind pressure switch 6 is caused by the pressure chamber 65 having a low pressure displacing the diaphragm 67 due to the pressure difference between the positive pressure and the negative pressure, overcoming the biasing force of the spring 66, and causing the rod 68 interlocked with the diaphragm 67 to move. Contact 69 is closed.

Furthermore, in the combustion air flowing from upstream to downstream of the protrusion 45 within the scroll casing 42, negative pressure is generated directly under the protrusion 45 even if the rotation speed of the fan 40 is low, so in the wind pressure switch 6 of the present invention. It is possible to stably detect negative pressure regardless of the rotational speed of the fan 40.

When the contact point 69 of the wind pressure switch 6 is opened, the electronic control circuit 7 outputs an output to the on-off valve and the proportional control valve of the gas control unit 53 to open the on-off valve and the proportional control valve.

Therefore, fuel gas flows out from the three gas jet ports 55 downstream of the protrusion 45. Then, this fuel gas is transferred to the protrusion 4
Since the fuel gas is injected into the negative pressure generation area downstream of the fuel gas 5, the fuel gas is sucked into the scroll casing 42 by the negative pressure.

The fuel gas sucked into the scroll casing 42 is
The fuel gas is agitated by the vortex generated downstream of the protrusion 45 and is also carried by the combustion air flowing between the fan 40 and the scroll casing 42, thereby diffusing the fuel gas throughout the air supplied to the burner 21. It is possible to stably supply fuel gas that is uniformly diffused to the area.

Therefore, a uniform air-fuel ratio can be obtained throughout the burner 21, and incomplete combustion due to uneven supply of fuel gas can be prevented.

Further, the fuel gas flowing out from the gas jet port 55 is
5, the fuel gas can be stably supplied to the burner 21 even in the case of slight combustion in which the amount of fuel gas supplied is small, for example.

Here, when the centrifugal air blower 4 stops rotating due to some kind of failure (motor failure, disconnection of the electric wiring of the motor, etc.) and suction of combustion air from the suction port 41 of the scroll casing 42 stops, the wind pressure The switch 6 is connected to a pressure chamber 62 in which a diaphragm 67 has a low pressure due to a pressure difference between positive pressure and negative pressure.
It is displaced by the biasing force of the spring 66, and the contact 69 is opened by the pin 68 which is interlocked with the diaphragm 67.

By opening the contact point 69 of the wind pressure switch 6, the electronic control circuit 7 outputs an output to the on-off valve and the proportional control valve of the gas control unit 53, and closes the on-off valve and the proportional control valve.

For this reason, the outflow of the i) and i+ gases from the three gas jet ports 55 downstream of the protrusion 45 is stopped.

Therefore, when suction of combustion air is stopped, it is possible to reliably avoid the risk of releasing coal monoxide or raw gas in the burner 21 due to incomplete combustion or flame extinction.

Figures 4 to 6 show the second part of the blowing pressure detection device of the present invention.
An example is shown.

In this embodiment, two ejection passages 57 are provided at the tip (on the left in FIG. 5) of the gas ejection nozzle 51, and the ejection passages 57 are located downstream of the protrusion 45, as shown in FIG. Directly below 44, two gas ejection ports 58 are formed. Further, a negative pressure detection hole 81 connected to the wind pressure switch 6 via a connecting pipe 82 is arranged in parallel with the gas outlet 58 directly below the protrusion 45 downstream 44 .

In this embodiment, both positive pressure and negative pressure are detected by the wind pressure switch, but a wind pressure switch that detects only negative pressure or positive pressure to detect the wind pressure of the fan may also be used.

In this embodiment, since the negative pressure detection hole 81 is not provided in the ejection path 57 of the gas ejection nozzle 51, there is no resistance to introducing negative pressure due to the outflow of fuel gas, so that the wind pressure switch can be switched more reliably than in the first embodiment. 6 can introduce negative pressure.

In this example, the shape of the protrusion was such that the upstream side was upright and the downstream side was inclined. Any other shape may be used as long as this occurs.

In this embodiment, the protrusions were formed over the entire width of the scroll casing, but the protrusions may also be formed on a part of the scroll casing. In this case, the gas outlet and negative pressure detection hole are also formed on the protrusions. It suffices to provide it in a part of the downstream.

In this example, the scroll casing and the gas jet nozzle are integrally molded, but they may be provided separately. In this case, the protrusion and the negative pressure detection hole are integrally formed at the gas jet port of the gas jet nozzle. By molding, the present invention can be applied without significantly modifying the scroll casing.

In this embodiment, the protrusions are integrally molded onto the scroll casing, but the protrusions may be formed separately from the scroll casing or the gas ejection nozzle.

In this embodiment, the blowing pressure detection device of the present invention is applied to a forced air gas water heater, but it may also be applied to other gas combustion devices such as a bathtub or a combustion heating device.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a blowing pressure detecting device for a forced air gas water heater to which the first embodiment of the blowing pressure detecting device of the present invention is applied, and Fig. 2 is a diagram of a scroll casing according to the first embodiment of the present invention. FIG. 3 is an enlarged sectional view of the gas jet nozzle according to the first embodiment of the present invention, and FIG. 4 is a perspective view of the protrusion formed on the inner circumferential surface of the scroll casing according to the second embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view of a gas ejection nozzle according to a second embodiment of the present invention, and FIG. 6 is an enlarged cross-sectional view of a negative pressure detection hole according to a second embodiment of the present invention. be.

Claims (1)

[Claims] 1) A fan provided in a fan case, a protrusion provided on the inner peripheral surface of the fan case between the fan and the fan case, and a protrusion of the fan case near the protrusion. A blowing pressure detection device comprising: a detection hole provided on an inner circumferential surface; and a wind pressure switch connected to the detection hole and configured to detect blowing pressure of the fan. 2) the detection hole is provided directly below the upstream side of the protrusion;
2. The blowing pressure detection device according to claim 1, wherein the wind pressure switch detects positive pressure through the detection hole. 3) the detection hole is provided directly below the downstream side of the protrusion;
2. The blowing pressure detecting device according to claim 1, wherein the wind pressure switch detects negative pressure generated immediately downstream of the protrusion through the detection hole. 4) The portion where the negative pressure is generated is provided with a gas ejection passage that discharges fuel gas and has a gas ejection port formed on the inner circumferential surface of the fan case. The air blowing pressure detection device according to scope 3. 5) The blowing pressure detection device according to claim 4, wherein the detection hole is formed in the gas ejection path. 6) The blowing pressure detection device according to claim 4, wherein the detection hole is arranged in parallel with the gas ejection port.