JPH048900A - Air blower - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to an axial flow or blower device used in oil hot air heaters and the like.

BACKGROUND ART As shown in FIG. 2, a conventional blower device of this type has a driving motor 2 located on the suction side of an impeller 1, and a rounded orifice on the suction side surrounding the impeller. 3 is provided. Further, the motor 2 is supported by a U-shaped indicator fitting 4, and by fixing both ends of the indicator fitting 4 to the orifice 3, the impeller 1 is kept in the center of the orifice 3.

A combustion tube 5 is provided on the discharge side of the impeller 1, and is surrounded by a blower duct 7 that guides the flow from the impeller 1 to an outlet 6. One end of the blower duct 7 is connected to the orifice 3, so that the air sent from the impeller 1 does not flow back to the suction side.

When the impeller 1 is rotated with the above configuration, cold air on the upstream side passes around the motor 2 and flows into the blower duct 7 while being cooled. The air flows around the combustion tube 5, becomes warm air, and is discharged from the outlet 6.

Problems to be Solved by the Invention However, the performance of conventional air blowing devices as described above is not fully satisfied, and as devices become smaller and thinner, even higher performance is desired. For example, most conventional impellers have a ratio of blade height to blade outer diameter of 0.25 or more, but if you simply reduce the blade height when making the blade thinner, the pressure characteristics will deteriorate and the rotation Various problems arise, such as an increase in the number of devices and an increase in noise, so some kind of improvement is needed.

In order to improve the performance of a blower, it is common to optimize the shape of the impeller and orifice.

However, in combustion equipment such as oil hot air heaters, the impeller and orifice are located close to the heat source, so the structure must be able to withstand the heat.

For this reason, metal parts such as impellers and orifices are often formed by sheet metal processing, and the degree of freedom in shape is limited due to processing problems. For example, the area and thickness of the blade, or the curved shape of the orifice. In particular, with regard to the orifice, it is difficult to provide curved surfaces on both the suction side and the blowout side, which has been a bottleneck in improving performance. In other words, in a configuration in which a curved surface is provided only on the suction side as shown in Fig. 2, the flow on the suction side is smooth, but
A large vortex region, indicated by arrow a, is generated on the outlet side, leading to a loss of engineering capacity.

As described above, conventional air blowing devices have had the problem of not being able to sufficiently meet recent performance demands.

The present invention is intended to solve such conventional problems, and aims to provide a high-performance air blower for an oil-burning hot air heater using sheet metal parts with a simple shape and good workability. be.

Means for Solving the Problems In order to solve the above problems, the blower device of the present invention includes an impeller having a driving motor attached to the suction side, and a substantially cylindrical combustion tube located on the discharge side of the impeller. , comprising an orifice surrounding an impeller, the impeller having a ratio of axial height to blade outer diameter of 0.23 or less, and the orifice having a bell mouth portion formed with a curved surface on the suction side; The part from the position where the inner diameter is the smallest to the blowout side has a conical enlarged portion.

Function: With the above-described structure, the present invention has a curved surface on the suction side of the orifice, and the discharge side has a conically expanded shape, so not only the suction flow but also the blowout flow flows smoothly, reducing losses such as separation. can be suppressed. Furthermore, the diagonal flow is stabilized by the enlarged portion, and the pressurization effect due to centrifugal force is effectively utilized.

Example Embodiments of the present invention will be described below based on the accompanying drawings.

Note that parts that are the same as those in the conventional example are given the same numbers as in FIG. 2, and explanations thereof will be omitted.

In FIG. 1, 8 is a thin impeller, and 9 is an orifice. The thin impeller 8 has a ratio of blade height to blade outer diameter of 0.23.
It is about 20% thinner than the conventional one. Further, the orifice 9 has a bell mouth portion 10 formed of a curved surface and an enlarged portion 11 that expands into a conical shape at an angle of about 45 degrees.
is formed from. At this time, the inner diameter of the orifice 9 is the smallest at the connection portion between the bell mouth portion 10 and the enlarged portion 11. Processing the orifice 9 like this requires more effort than that shown in the conventional example, but it can be done by a series of press processes.

In this configuration, the flow generated by rotating the thin impeller 8 is as follows. First, the flow on the suction side flows widely from the entire circumference as shown by the arrow, and the flow from the side flows toward the bell mouth portion 10 and is sucked in.

On the other hand, the flow blown out from the thin impeller 8 is caused by the influence of the combustion cylinder 5 on the downstream side and the resistance of the ventilation passage itself.
The flow spreads out as shown in . Air near the center of this flow passes around the combustion tube 5 and is discharged from the outlet 6. Furthermore, since the flow that has flowed in along the bell mouth portion 10 flows along the enlarged portion 11 on the blowout side, a large vortex region unlike the conventional example does not occur.

Furthermore, the expanded flow is aligned along the enlarged part 11, and the flow is expanded.

By electrifying it, it is possible to obtain a pressurizing effect due to centrifugal force, so even a thin impeller can obtain sufficient pressure characteristics.

In this way, by combining the orifice 9 with the bell mouth portion lO and the enlarged portion 11 and the thin impeller 8,
A high-performance blower device that suppresses loss due to vortices in the blowing flow can be obtained.

Effects of the Invention As described above, according to the blowing device of the present invention, by providing the hell mouth portion on the suction side of the orifice and the enlarged portion on the discharge side, both suction and discharge flows are smoothly strained and vortexed. It is possible to suppress the heavy losses.

In addition, by realizing stable oblique blowing, a pressurizing effect due to centrifugal force can be obtained, and a decrease in pressure characteristics due to the thin impeller can be suppressed.

Therefore, it is possible to realize a highly efficient flow without impairing the workability of constituent elements such as the orifice, and the effect of improving the performance of the blower device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an air blower according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional air blower. 1... impeller, 2... motor, 5...
... Combustion cylinder, 8 ... - Thin impeller, 9 ...
... Orifice, 10 ... Hellmouth part, 1
1... Enlarged section. Name of agent: Patent attorney Shigetaka Awano and one other person

Claims (1)

[Claims] The impeller has an impeller with a drive motor attached to the suction side, a nearly cylindrical combustion cylinder located on the discharge side of the impeller, and an orifice surrounding the impeller. The ratio of the diameter of the orifice to the outer diameter of the blade is 0.23 or less, and the orifice has a bell mouth portion formed with a curved surface on the suction side, and an enlarged portion that expands into an almost conical shape from the position where the inner diameter is the smallest on the blowout side. The blower device.