JPH1137090A - Fan for gas water heater or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high durability and heat resistance so as to be usable in a high-temperature high-humidity atmosphere by integrally forming an impeller of PBT(polybuteneterephthalate) resin with glass fiber mixed therein. SOLUTION: Fuel gas and air blasted by an air blasting fan are mixed in a burner part, burnt in a combustion chamber and heat-exchanged with water in a heat exchanger provided at the combustion chamber, thus heating water. In a gas water heater or the like of such constitution, a sirocco fan is provided with an impeller 4 of the air blasting fan composed of a disc-like base 4a, a large number of blades 4b arranged in cylindrical shape at one side face of the base 4a, and a boss part 4e provided at the central part of the base 4a so as to fit the impeller 4 to a rotary shaft 5a of a fan motor 5. The impeller 4 is integrally formed of PBT(polybuteneterephthalate) resin with glass fiber mixed therein. The impeller 4 is therefore excellent in durability and heat resistance and underformed by water absorption so as to be safely usable for the air blasting fan for the gas hot-water feeder or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower fan used for a gas water heater or the like.

[0002]

2. Description of the Related Art Conventionally, a gas water heater as shown in FIG.
A blower fan b for supplying combustion air to the burner section a is provided at a lower portion. The air blown to the burner section a by the blower fan b is mixed with the fuel gas, the flow rate of which is controlled by the fuel control section c, in the burner section a and is ejected to the combustion chamber d, where it is burned in the combustion chamber d. After the heat exchange with the water by the heat exchanger e, the exhaust gas generated by the combustion is discharged to the atmosphere from the upper exhaust port f, and the water heated by the heat exchanger e is sent to a hot water supply pipe (not shown). It is sent out.

In addition, a sirocco fan with little noise is often used as the fan b for the gas water heater as described above. For example, a sirocco fan is used as the fan in Japanese Patent Application Laid-Open No. 6-241441. An impeller for a blower comprising a water heater and a sirocco fan has been proposed in Japanese Utility Model Laid-Open No. 57-182300.

[0004]

However, since the conventional sirocco fan described in the above publication uses an assembly made of metal such as aluminum having high heat resistance, it is heavy and expensive. There is a defect such as.

[0005] In order to solve such a problem, a sirocco fan integrally formed of resin has been proposed. However, in a normal gas water heater, the ambient temperature of the blower fan is as high as about 150 ° C. In this case, thermal deformation occurs and it is difficult to use.

For this reason, use of a sirocco fan molded of a heat-resistant resin such as 6,6 nylon having high heat resistance has been considered. However, since nylon resin has water absorbency, when it is used for gas water heaters, it is difficult to use hot water. The fan absorbs the water vapor generated at this time, causing the fan to deform, causing the fan to deform, resulting in poor rotation, reduced airflow, and noise caused by the blades contacting surrounding components. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and has as its object to provide a fan for a gas water heater or the like which has high heat resistance and has no fear of being deformed by moisture or the like. .

[0008]

In order to achieve the above object, the invention according to claim 1 is to mix air and fuel gas blown by a blower fan in a burner section and burn them in a combustion chamber, and In a gas water heater or the like in which water is heated by exchanging heat with water in a heat exchanger provided in a combustion chamber, the impeller of the blower fan is mounted on a disc-shaped substrate and on one side of the substrate. A large number of blades arranged in a cylindrical shape, and a siccolo fan that is provided at the center of the substrate and has a boss portion for attaching the impeller to a rotation shaft of a fan motor, and the impeller is made of glass. It is formed integrally with a PBT (polybutene terephthalate) resin mixed with fibers.

With the above structure, high durability and heat resistance can be obtained, and there is no deformation by absorbing moisture.
It is possible to prevent poor rotation due to deformation of the fan, a decrease in wind power, and an increase in noise due to contact with peripheral components.

In order to achieve the above object, the invention according to claim 2 uses a serration nut having a plurality of projections on a fastening surface for a nut for fixing a boss portion of an impeller to a rotation shaft of a fan motor. .

According to the above configuration, when the serration nut is tightened, the projection bites into the boss portion, so that the impeller can be securely mounted and the serration nut does not become loose during use.

According to the third aspect of the present invention, a flat surface is formed over substantially the entire length of the corner of the impeller on the side of the outlet.

[0013] According to the above configuration, when the impeller is injection-molded, burrs are not generated at the corners, so that pressure loss due to burrs can be prevented.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings shown in FIGS. FIG. 2 is a schematic view of a state used for a gas water heater, FIG. 3 is a sectional view taken along line AA of FIG. 2, and FIG. 4 is a perspective view of an impeller.

In these figures, reference numeral 1 denotes a blower fan composed of a sirocco fan, which comprises a casing 3 installed below a burner 2 of a gas water heater and an impeller 4 provided in the casing 3. The center portion is fixed to a rotating shaft 5a of the fan motor 5 via a serration nut 6, and is rotated by the fan motor 5 in the direction of the arrow in FIG.

As shown in FIG. 3 and subsequent figures, the impeller 4 has a plurality of, for example, forty-eight, blades 4b provided on one side surface of a disk-shaped substrate 4a at equal intervals in the circumferential direction. A circular cylinder is formed by the blades 4b, and the outer peripheral portions on the tip side of the blades 4b are connected to each other by an annular portion 4c.
Each blade 4b is reinforced.

By projecting the central portion of the substrate 4a in a frusto-conical shape inside, a concave portion 4d is formed on the fan motor 6 side.
Is formed, and a boss 4e is formed in the center of the substrate 4a. The rotation shaft 5a of the fan motor 5 is inserted through a mounting hole 4f opened at the center of the boss 4e. The rotating shaft 5a is fixed to the rotating shaft 5a by tightening a serration nut 6 screwed to the tip of the rotating shaft 5a.

The serration nut 6 is shown in FIG.
As shown in (b) and (b), a plurality of protrusions 6
b is projected. These projections 6b are wedge-shaped, and when the serration nut 6 is tightened, they bite into the end face of the boss 4e, so that the fixing force of the impeller 4 is strengthened.

On the other hand, the impeller 4 is made by integrally molding a mixture of PBT resin and glass fiber by injection molding in order to enhance durability and heat resistance. The impeller 4 has a temperature of 200 ° C. which can sufficiently withstand the use environment of the gas water heater. It has the above heat resistance.
The PBT resin has a water absorption of 1.8% (23%) of nylon.
(Immersed in warm water at 24 ° C for 24 hours), which is extremely low at 0.06%. Therefore, even if moisture adheres during use, it does not absorb or deform, and has stable performance even in high temperature and high humidity atmosphere Can be maintained.

When the impeller 4 is injection molded, each of the impellers 4
As shown in FIG. 6A, burr 7 does not occur at the corner on the outlet side of b, and approximately the entire width of about 0.3 mm as shown in FIG. Flat surface 4
g is formed.

When the impeller 4 is rotated in the direction of the arrow in FIG. 2, the air is blown out between the base ends of the blades 4b. Since the generation of air 7 has an adverse effect on the air blowing, the impeller 4 of the present invention having no burr 7 at the corner on the side of the air outlet of each blade 4b was rotated at 4000 rpm. As a result, the static pressure was 45 mmH _2. O, static pressure about 39 in multiple experiments
４２42 mmH ₂ O (6 to 12%), whereas the impeller 4 in which burrs 7 have formed at the corners on the outlet side of each blade 5 b obtains a static pressure of 45 mmH ₂ O, It was confirmed that the car 4 had to be rotated at about 4400 rpm, which increased the load on the fan motor 5 and increased power consumption.

If the flat surface 4g is formed at an acute angle, the resin does not sufficiently flow during molding if the angle is an acute angle, so that a waveform may be poorly formed and the same problem as described above may occur. However, by forming the flat surface 4g in advance, it is possible to prevent the occurrence of molding failure.

[0023]

As described in detail above, the present invention provides a PBT mixed with glass fibers in order to improve durability and heat resistance.
Since the impeller is integrally formed of resin and has much lower water absorption than nylon resin, it does not deform due to moisture even when used as a blower fan such as a gas water heater. This causes poor rotation due to deformation of the fan,
Problems such as a decrease in wind power and an increase in noise due to contact with surrounding components can be eliminated.

In order to fix the impeller to the rotating shaft of the fan motor, a serration nut having a plurality of projections on a fastening surface is used. The projections bite into the boss of the impeller by tightening the serration nut. This prevents the serration nut from loosening during use, thereby preventing the impeller from falling off.

Furthermore, since a flat surface is formed at the corner on the outlet side of each blade over substantially the entire length, burrs and molding defects may occur at the corner when molding the impeller. In addition, this makes it possible to eliminate problems such as a decrease in static pressure due to burrs and molding defects, and also reduces the load on the fan motor, thereby reducing power consumption.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a conventional gas water heater.

FIG. 2 is a configuration diagram showing a blower fan such as a gas water heater according to the embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a perspective view showing an impeller of the blower fan according to the embodiment of the present invention.

FIG. 5 (a) is a side view of a serration nut used for fixing the blower fan according to the embodiment of the present invention. (B) It is a front view of the fastening surface side.

FIG. 6A is an explanatory view of an impeller in which burrs are generated at a corner on the side of the outlet. (B) It is explanatory drawing of the impeller which formed the flat surface in the corner part at the side of the outlet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fan for blowing, 2 ... Burner part, 3 ... Casing, 4
… Impeller, 4a… substrate, 4b… blade, 4e… boss part, 4
g: flat surface, 5: fan motor, 5a: rotating shaft, 6: serration nut, 6a: fastening surface, 6b: projection.

Claims (3)

[Claims] An air blown by a blower fan and a fuel gas are mixed in a burner section, burned in a combustion chamber, and heat-exchanged with water in a heat exchanger provided in the combustion chamber. In gas water heaters that heat water,
An impeller 4 of the blower fan 1 is provided with a disc-shaped substrate 4a,
A plurality of blades 4b arranged in a cylindrical shape on one side surface of the substrate 4a, and a boss portion 4e provided at the center of the substrate 4a and for attaching the impeller 4 to the rotation shaft 5a of the fan motor 5 Along with the sirocco fan
A blower fan for a gas water heater or the like, wherein the impeller 4 is integrally formed of PBT (polybutene terephthalate) resin mixed with glass fiber. 2. The boss 4e of the impeller 4 is connected to a fan motor 5
2. A blower fan for a gas water heater or the like according to claim 1, wherein a serration nut 6 having a plurality of projections 6b on a tightening surface 6a is used as a nut fixed to the rotating shaft 5a. 3. A blower fan for a gas water heater or the like according to claim 1, wherein a flat surface 4g is formed over substantially the entire length at a corner of the blade 4b of the impeller 4 on the outlet side.