JP2001082780A - Underfloor ventilator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost of an underfloor ventilator in which generation of noises, reduction of supply air and incomplete rotation of a fan can be prevented. SOLUTION: Inner circumferential surface of a fan scrolling casing 7 is constituted of a partial arc concentric to the outer circumferential surface of a centrifugal fan fixed with three blades 16. Inside diameter of an air inlet is made constant in the ventilating direction. Since intricate operations are not required in the design of the fan scrolling casing 7 and the air inlet and the number of parts is decreased, manufacturing cost can be reduced. Since the interval between the inner circumferential surface of the fan scrolling easing 7 and the outer circumferential surface of the centrifugal fan is not extremely limited partially, clogging with foreign matter, e.g. dust, is eliminated. Furthermore, the centrifugal fan is prevented from abutting against the inner circumferential surface of the fan scrolling casing 7 due to error in the dimensions of the centrifugal fan or the fixing position thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underfloor ventilator for forcibly exhausting the air under the floor of a house to the outside.

[0002]

2. Description of the Related Art Generally, high humidity air tends to accumulate under the floor of a house, and if left unchecked, the life of the house is shortened due to the occurrence of mold and the propagation of termites. For this reason, an underfloor ventilator has conventionally been commercialized in which the air in the underfloor is forcibly exhausted to the outside by the rotation of a fan driven by a motor.

As shown in FIG. 14, this underfloor ventilator has a suction port 2 exposed inside the underfloor 1 and a blowout port 4 exposed outside the underfloor 3, and has a fan 6 driven by a motor 5 therein. A housing is provided with a fan scroll casing 7 which is rotatably supported, and is arranged in a vent 8 formed in a rising portion of a foundation of a house.

In the conventional underfloor ventilator, as shown in FIG. 15, the internal shape of the fan scroll casing 7 has a spiral shape in which the distance from the outer peripheral surface of the fan 6 gradually increases toward the outlet 4. Thus, a tongue 19 was formed near the side end of the air outlet 4 in the air flow path. Also,
As the fan 6, a multi-blade centrifugal fan such as a so-called sirocco fan has been used.

[0005]

However, in the conventional underfloor ventilation device, since the internal shape of the fan scroll casing is spiral, a complicated calculation using an exponential function is required at the time of design, and the manufacturing cost increases. There was a problem. Also, since the distance between the outer peripheral surface of the fan and the inner peripheral surface of the fan scroll casing is extremely small in the portion where the tongue is formed, foreign matter such as dust flowing into the fan scroll casing from the suction port together with air is reduced. There is a problem that the fan is likely to be clogged, and the rotating fan comes into contact with foreign matter to generate noise, the air flows backward (20 shown in FIG. 14), and the fan cannot be rotated. Positional errors can also result from direct contact of the outer peripheral surface of the fan with the tongue.

Further, the conventional underfloor ventilator uses a multi-blade centrifugal fan, which not only causes an increase in manufacturing cost, but also because foreign matters such as dust easily accumulate due to the small space between the blades, and noise. And there is a problem that the amount of air blows is reduced and frequent maintenance is required.

An object of the present invention is to reduce the manufacturing cost of the fan scroll casing and the fan, and to prevent foreign matters such as dust from clogging in the air flow path in the fan scroll casing and the fan. It is an object of the present invention to provide an underfloor ventilator capable of preventing noise, reducing the amount of air flow, and preventing poor rotation of a fan.

[0008]

The present invention has the following arrangement as means for solving the above-mentioned problems.

(1) The inside shape of the fan scroll casing that communicates with the inside of the floor at the suction port and the outside of the floor at the air outlet and that supports the centrifugal fan is constituted by an arc centered on the rotation axis of the centrifugal fan. It is characterized by having done.

In this configuration, the inside of the fan scroll casing through which the air under the floor passes from the suction port to the air outlet by the rotation of the centrifugal fan is formed concentrically with the outer periphery of the centrifugal fan. Therefore, the interval between the inner peripheral surface of the fan scroll casing and the outer peripheral surface of the centrifugal fan is substantially uniform over the entire circumference, and the interval does not become extremely narrow in part. Even when there is an error in the shape and mounting position of the fan, the outer peripheral surface of the fan does not contact the inner peripheral surface of the fan scroll casing, resulting in noise and poor rotation of the fan There is no. In addition, complicated design is not required for designing the internal shape of the fan scroll casing.

(2) The inner diameter D of the fan scroll casing satisfies the relationship of 0.6 ≦ d1 / D ≦ 0.9, where d1 is the outer diameter of the centrifugal fan.

In this configuration, the inner diameter D of the fan scroll casing for securing the air volume required for ventilation under the floor is calculated by a very simple algebraic calculation based on the outer diameter d1 of the centrifugal fan. Therefore, the internal shape of the fan scroll casing having a predetermined air volume can be designed very easily.

(3) The inner diameter D of the fan scroll casing satisfies the relationship of 0.75 ≦ d1 / D ≦ 0.85, where d1 is the outer diameter of the centrifugal fan.

In this configuration, the inner diameter D of the fan scroll casing for making the air volume, the blowing efficiency and the noise volume more appropriate is calculated by a very simple algebraic calculation based on the outer diameter d1 of the centrifugal fan. Therefore, the internal shape of the fan scroll casing with more appropriate air volume, air blowing efficiency and noise amount can be designed very easily.

(4) The suction port is a circular hole having a constant inner diameter in the air passage direction.

In this configuration, the inside diameter of the suction port is made constant in the air passage direction. Therefore, it is not necessary to form a special shape such as a throttle at the suction port, and the manufacturing cost of the fan scroll casing is reduced.

(5) The inside diameter d2 of the suction port satisfies the relationship of 0.3 ≦ d2 / D ≦ 0.8, where D is the inside diameter of the fan scroll casing.

In this configuration, the inside diameter d2 of the suction port for allowing a large amount of air under the floor to flow into the fan scroll casing from the suction port is calculated by an extremely simple algebraic calculation based on the inside diameter D of the fan scroll casing. Is done. Therefore, the shape of the fan scroll casing having a sufficient air flow for exhausting the air under the floor to the outside is designed very easily.

(6) The internal diameter d2 of the suction port satisfies the relationship of 0.4 ≦ d2 / D ≦ 0.6, where D is the internal diameter of the fan scroll casing.

In this configuration, the inner diameter d2 of the suction port for making the air volume, the blowing efficiency and the noise amount more appropriate is calculated by an extremely simple algebraic calculation based on the inner diameter D of the fan scroll casing. Therefore, the air volume,
The shape of the fan scroll casing with more appropriate blowing efficiency and noise amount can be designed very easily.

(7) The centrifugal fan is characterized in that the number of blades is Z, the chord length is C, and the outer diameter is d1, and the relationship of CZ / d1 ≦ 5 is satisfied.

In this configuration, the number Z of blades of the centrifugal fan is calculated by a very simple algebraic calculation based on the ratio of the product of the chord length C and the number Z of blades to the outer diameter d1 of the centrifugal fan. Therefore, a centrifugal fan for ensuring a sufficient air volume in the fan scroll casing is designed very easily.

(8) The centrifugal fan is characterized in that the number of blades is two.

In this configuration, a centrifugal fan having two blades is used. Therefore, as compared with the case of using a multi-blade centrifugal fan, the component cost is reduced, and the distance between the blades is maximized. No loud noise is generated and the air volume is not reduced.

(9) The centrifugal fan is formed of a single plate.

In this configuration, the two blades are formed by a single plate. Therefore, a centrifugal fan that does not generate a loud noise or reduce the air volume can be manufactured very easily.

(10) The centrifugal fan has three blades.

In this configuration, a centrifugal fan having three blades is used. Therefore, as compared with the case of using a multi-blade centrifugal fan, the component cost is reduced, and the distance between the blades is increased, so that the centrifugal fan is not clogged with foreign matter such as dust. No loud noise is generated and the air volume is not reduced.

(11) The centrifugal fan has an angle θ formed by a straight line connecting the rotation center and the inner end of the blade and a straight line connecting the inner end and the outer end of the blade. Is set to be positive, −40 ° ≦ θ ≦ 90 ° is set.

In this specification, the forward wing refers to a wing whose inner end is located behind the outer end in the rotation direction of the centrifugal fan, and the backward wing refers to the wing whose inner end is rotated by the centrifugal fan. A wing located forward of the outer edge in the direction.

In this configuration, the angle of the blade in the centrifugal fan is set within a predetermined range. Therefore, the most suitable shape of the centrifugal fan is selected according to the air volume of the fan scroll casing and the rotation speed of the centrifugal fan.

(12) In the centrifugal fan, an angle θ formed between a straight line connecting the rotation center and the inner end of the blade and a straight line connecting the inner end and the outer end of the blade is defined as a positive value in the case of the backward facing blade. ° ≦ θ ≦ 60 ° is set.

In this configuration, the angle of the blades in the centrifugal fan is set to a state in which the air volume, the blowing efficiency, and the noise volume are made more appropriate. Therefore, a centrifugal fan with more appropriate air volume, air blowing efficiency, and noise amount can be easily designed.

(13) The centrifugal fan has an angle θ between a straight line connecting the rotation center and the inner end of the blade and a straight line connecting the inner end and the outer end of the blade.
° is set.

In this configuration, the angle of the blades in the centrifugal fan is set to a state that optimizes the air volume, the blowing efficiency, and the noise amount. Therefore, a centrifugal fan with the optimal air volume, air blowing efficiency and noise amount can be easily designed.

(14) The centrifugal fan has a flat blade shape.

In this configuration, a centrifugal fan having flat blades is used. Therefore, the centrifugal fan is very easily designed and manufactured.

[0038]

1 and 2 show a first embodiment of the present invention.
It is the side sectional view and plane sectional view showing the composition of the under floor ventilation device concerning an embodiment. The underfloor ventilation device 17 communicates with the underfloor interior 1 through the suction port 2 formed on the upper surface,
A fan motor 5, a centrifugal fan 6, and a fan scroll casing 7 are provided in a casing 9 that communicates with the underfloor outside 3 through an outlet 4 formed on the front surface.
The underfloor ventilation device 17 is installed in the ventilation hole 8 formed at the rise of the foundation of the house with the ventilation space 11 formed on the upper surface of the casing 9. Further, a makeup grill 13 is arranged at the outlet 4, and an electric transmission box 14 is attached to the back of the casing 9.

As shown in FIG. 2, the inner peripheral surface of the fan scroll casing 7 is
/ 4 arc. The suction port 2 is not given a complicated shape such as a so-called bell mouth, and the inside diameter of the suction port 2 is constant in the vertical direction which is the ventilation direction. The inner diameter d2 of the suction port 2 is set to a size that satisfies the relationship of d2 / D = 0.5 with respect to the inner diameter D of the fan scroll casing 7. Further, the outer diameter d1 of the centrifugal fan 6 is set to a size satisfying the relationship of d1 / D = 0.8 with respect to the inner diameter D of the fan scroll casing 7.

With this configuration, the centrifugal fan 6 rotates inside the fan scroll casing 7 with an appropriate interval formed between the fan scroll casing 7 and the inner peripheral surface of the fan scroll casing 7. When the distance between the inner peripheral surface of the fan scroll casing 7 and the outer peripheral surface of the centrifugal fan 6 is reduced, there is no possibility that foreign matter such as dust flowing in from the suction port 2 will not be partially clogged. The fan 4 can be discharged from the outlet 4 to the outside of the floor 3, and the centrifugal fan 6 does not abut on a part of the inner peripheral surface of the fan scroll casing 7 due to an error in the dimensions and mounting position of the centrifugal fan 6.
Reduction of air flow, generation of excessive noise, and centrifugal fan 6
Can be prevented from stopping in advance.

Further, since it is difficult for dust to stay in the fan scroll casing 7, it is possible to prevent an increase in the amount of moisture in the fan scroll casing 7 due to the absorption of moisture generated by dew condensation or the like by dust. The frequency of the maintenance of the underfloor ventilation device 17 can be reduced by suppressing the occurrence of the like.

Further, there is no partial backflow caused by rotation of a general centrifugal fan, a sufficient air volume can be secured, and no loud noise is generated. In addition, it is not necessary to provide a complicated shape such as a so-called bell mouth in the suction port 2 of the casing 9, and it is not necessary to use an exponential function in designing the fan scroll casing 7, so that the manufacturing cost can be reduced.

The centrifugal fan 6 rotates in the direction of arrow A in the fan scroll casing 7 and has three flat blades 16 mounted at equal intervals (120 °) in the plane of rotation. The blade 16 is a rotating shaft 1 of the centrifugal fan 6.
The angle θ formed between a straight line connecting the inner end of the wing 16 with the inner end of the wing 16 (front edge in the rotational direction) and a straight line connecting the outer end of the wing 16 (rear edge in the rotational direction) and the inner end is It is attached to the centrifugal fan 6 so that it becomes 40 °. The chord length C of the blade 16 is set to a length that satisfies the relationship of CZ / d1 = 1.2 with respect to the number Z of blades in the centrifugal fan 6 and the outer diameter d1 of the centrifugal fan 6. Further, the height of the blades 16 of the centrifugal fan 6 is set to the maximum size as long as the rotation of the centrifugal fan 6 in the fan scroll casing 7 is not hindered.

As described above, since the centrifugal fan 6 includes a small number of flat blades 16, the design of the blade 16 is facilitated, and the number of parts of the centrifugal fan 6 can be reduced. The manufacturing cost can be further reduced. Further, the interval between the wings 16 can be increased,
Foreign matter such as dust does not cause clogging between the blades 16, and does not cause a reduction in the amount of air blow or an increase in maintenance frequency.

FIG. 3 is a diagram showing the results of comparing the PQ characteristics, efficiency, and specific noise value of the underfloor ventilation device according to the embodiment with the same power consumption (fixed at 10 W) with those of the conventional underfloor ventilation device. . As shown in the figure, the underfloor ventilation device 17 according to the above embodiment is equal to or more than the conventional underfloor ventilation device in all of the performance, efficiency, and specific noise value.

FIG. 4 shows one example of the results of measuring the PQ characteristic, efficiency and specific noise value when the outer diameter of the centrifugal fan in the underfloor ventilation device according to the above embodiment is changed and the power consumption is constant (10 W constant). It is a figure which shows a part. Based on this result, the range of the outer diameter d1 of the centrifugal fan 6 that is compatible with the inner diameter D of the fan scroll casing 7 in the underfloor ventilation device 17 was determined. From the results of various experiments including results not shown, the outer diameter d1 of the centrifugal fan 6 used for the underfloor ventilation device 17 was determined.
With respect to the inner diameter D of the fan scroll casing 7, reasonable performance could be secured in the range of 0.6 ≦ d1 / D ≦ 0.9. In particular, the optimum air volume, efficiency and specific noise value could be obtained in the range of 0.75 ≦ d1 / D ≦ 0.85.

FIG. 5 shows a part of the measurement results of the PQ characteristic, the efficiency and the specific noise value at the same power consumption (10 W constant) when the inner diameter of the suction port is changed in the underfloor ventilation device according to the above embodiment. FIG. Based on this result,
The range of the inner diameter d2 of the suction port 2 that matches the inner diameter D of the fan scroll casing 7 in the underfloor ventilation device 17 was determined. From various experimental results including results not shown, the inner diameter d2 of the suction port 2 in the underfloor ventilation device 17 is appropriate with respect to the inner diameter D of the fan scroll casing 7 in a range of 0.3 ≦ d2 / D ≦ 0.8. Performance was secured. In particular, the optimum air volume, efficiency and specific noise value could be obtained in the range of 0.4 ≦ d2 / D ≦ 0.6.

FIGS. 6 and 7 show the PQ characteristic, efficiency and specific noise value at the same power consumption (fixed at 10 W) when the blade mounting angle of the centrifugal fan of the underfloor ventilation device according to the above embodiment is changed. It is a figure showing the result of measurement. Based on this result, the range of the mounting angle θ of the wing 16 that fits the underfloor ventilation device 17 was determined. From the experimental results shown in the figure, a proper performance could be ensured in the range of −40 ° ≦ θ ≦ 90 ° for the mounting angle θ of the wing 16 in the underfloor ventilation device 17. In particular, the optimum air volume, efficiency and specific noise value could be obtained in the range of −30 ° ≦ θ ≦ 60 °, and the best result was obtained at θ = 40 °.

In the results shown in FIG. 6 and FIG.
Is a positive value when the inner end of the blade 16 is located forward of the outer end in the rotational direction of the centrifugal fan 6 (in the case of a backward-facing blade), and the inner end of the blade 16 is
In the case where the rotation direction is located behind the outer end (in the case of the forward wing), a negative value is set.

Based on the above experimental results, the centrifugal fan 6
Outer diameter d1, inner diameter d2 of suction port 2 and mounting angle θ of blade 16
Is optimized to reduce the production cost by simplifying the structure and reducing the number of parts,
The underfloor ventilation device 17 excellent in efficiency and noise can be obtained.

The shape of the wings 16 can be any shape other than a flat plate, as long as the cost does not significantly increase. Further, the blades 16 need not necessarily be attached to the centrifugal fan 6 at equal intervals. However, if the blades 16 are attached at irregular intervals, it is necessary to make the weight balance uniform in order to prevent the occurrence of rotation unevenness of the centrifugal fan 6.

Further, the blade 16 attached to the centrifugal fan 16
Can be increased or decreased on the basis of CZ / d1 ≦ 5. In particular, in the range of 1.0 ≦ CZ / d1 ≦ 1.5, the centrifugal fan 6 having a low production cost and excellent blowing performance Can be obtained.

A centrifugal fan or a mixed flow fan can be used instead of the centrifugal fan 6. As shown in FIG. You may. In this case, a structure for increasing the strength of the fixed portion between the disk 21 and the blade 16 is required as compared with the configuration shown in FIG.

Also, a shape such as a so-called bell mouth can be added to the suction port 2 on condition that a significant increase in manufacturing cost does not occur.

FIG. 9 is a side sectional view showing a configuration of an underfloor ventilation device according to a second embodiment of the present invention. The underfloor ventilator 27 according to this embodiment differs from the underfloor ventilator 17 according to the first embodiment shown in FIG. 1 in that the motor 5 is arranged not in the casing 9 but in the ventilation space 11. are doing. As is apparent from the plan sectional view shown in FIG. 10, the number of blades 16 mounted on the centrifugal fan 6 is two. Otherwise, underfloor ventilation system 2
Reference numeral 7 is common to the underfloor ventilation device 17, and the same parts are denoted by the same reference numerals and description thereof is omitted.

According to the underfloor ventilation device 27 according to the second embodiment shown in FIGS. 9 and 10, in addition to the effect of the underfloor ventilation device 17 according to the first embodiment, a large amount of water flows into the inside. In this case, it is possible to reduce the possibility that the motor 5 will be flooded, thereby obtaining an effect of preventing a failure or an accident due to electric leakage. Further, the work of attaching the blade 16 to the disk 21 is reduced, and the manufacturing cost of the centrifugal fan 6 is further reduced.

The two blades 16 attached to the centrifugal fan 6 can be constituted by a single flat plate as shown in FIGS. 11 and 12, and in particular, as shown in FIG. By using the flat plate as it is, the manufacturing cost of the centrifugal fan 12 can be further reduced.

FIG. 13 is a side sectional view showing a configuration of an underfloor ventilation device according to a third embodiment of the present invention. The underfloor ventilation device 37 according to this embodiment is configured such that the casing 9 having the suction port 2, the outlet 4, the motor 5, the centrifugal fan 6, and the fan scroll casing 7 in the underfloor ventilation device 17 shown in FIG. It is installed in the mouth 8, the electric transmission box 14 is arranged in the ventilation space 11 formed below the casing 9, and the grill 22 is formed in the suction port 2.

With this configuration, according to the underfloor ventilator 37 according to the third embodiment, in addition to the replacement obtained by the underfloor ventilator 17 according to the first embodiment, the underfloor inside of the casing 9 is moved from the lower surface of the casing 9 to the first underfloor. Humid air can be efficiently discharged from the outlet 4 to the outside under the floor 3 through the inside of the fan scroll casing 7, and the humidity control function under the floor of the house can be improved.

By forming the grill 22 integrally with the casing 9, the number of parts can be reduced and the cost can be reduced. Similarly, by integrally forming the transmission box 14 with the casing 9, the number of parts can be reduced and the cost can be reduced.

[0061]

According to the present invention, the following effects can be obtained.

(1) The internal shape of the fan scroll casing, through which the air under the floor passes from the suction port to the air outlet by the rotation of the centrifugal fan, is formed concentrically with the outer periphery of the centrifugal fan. The distance between the inner peripheral surface of the centrifugal fan and the outer peripheral surface of the centrifugal fan can be made substantially uniform over the entire circumference, and the distance between the inner peripheral surface of the fan scroll casing and the outer peripheral surface of the centrifugal fan partially becomes extremely narrow. And prevents foreign matter such as dust from clogging, and prevents the outer peripheral surface of the fan from abutting against the inner peripheral surface of the fan scroll casing even when there is an error in the shape or mounting position of the fan. Therefore, noise and poor rotation of the fan due to these can be prevented. Also, the design of the internal shape of the fan scroll casing does not involve complicated calculations, and the manufacturing cost can be reduced.

(2) By calculating the inner diameter D of the fan scroll casing for securing the air volume required for ventilation under the floor by an extremely simple algebraic calculation based on the outer diameter d1 of the centrifugal fan, the predetermined air volume can be obtained. Can very easily design the internal shape of the fan scroll casing, and the manufacturing cost can be reduced.

(3) The inner diameter D of the fan scroll casing for making the air volume, air blowing efficiency and noise volume more appropriate is
By calculating by a very simple algebraic operation based on the outer diameter d1 of the centrifugal fan, the internal shape of the fan scroll casing with more appropriate air volume, air blowing efficiency and noise amount can be designed very easily, and the manufacturing cost can be reduced. It can be cheaper.

(4) By making the inside diameter of the suction port constant in the air passing direction, it is not necessary to form a special shape such as a throttle at the suction port, and the manufacturing cost of the fan scroll casing can be further reduced.

(5) The inside diameter d2 of the suction port for allowing a large amount of air under the floor to flow into the fan scroll casing from the suction port is calculated by an extremely simple algebraic calculation based on the inside diameter D of the fan scroll casing. Accordingly, the shape of the fan scroll casing having a sufficient air volume for exhausting the air under the floor to the outside can be extremely easily designed, and the manufacturing cost can be reduced.

(6) By calculating the inner diameter d2 of the suction port for making the air volume, air blowing efficiency and noise amount more appropriate by an extremely simple algebraic calculation based on the internal diameter D of the fan scroll casing, the air volume, The shape of the fan scroll casing having more appropriate efficiency and noise amount can be extremely easily designed, and the manufacturing cost can be further reduced.

(7) The number of blades Z of the centrifugal fan is calculated by an extremely simple algebraic operation based on the ratio of the product of the chord length C and the number of blades Z to the outer diameter d1 of the centrifugal fan, thereby providing fan scrolling. A centrifugal fan for ensuring a sufficient air volume in the casing can be designed very easily, and the manufacturing cost can be further reduced.

(8) By using a centrifugal fan having two blades, the cost of parts can be reduced as compared with the case of using a multi-blade centrifugal fan, and the distance between the blades is maximized. As a result, the centrifugal fan does not become clogged with foreign matter such as dust, and the generation of loud noise and a decrease in air volume can be prevented.

(9) By forming the two blades with a single plate, a centrifugal fan that does not generate loud noise and does not reduce the air volume can be manufactured very easily, and the manufacturing cost can be reduced. Can be reduced.

(10) By using a centrifugal fan having three blades, the cost of parts can be reduced as compared with the case of using a multi-blade centrifugal fan, and the distance between the blades can be increased. It is possible to prevent foreign matter such as dust from being clogged in the centrifugal fan, and to prevent loud noises and a decrease in air volume.

(11) By setting the angle of the blades in the centrifugal fan within a predetermined range, it is possible to select the optimum shape of the centrifugal fan according to the air volume of the fan scroll casing and the rotation speed of the centrifugal fan.

(12) By setting the angle of the blades in the centrifugal fan to a state in which the air volume, the blowing efficiency and the noise amount are more appropriate, a centrifugal fan with a more appropriate air volume, the blowing efficiency and the noise amount can be easily designed. it can.

(13) By setting the angle of the blades in the centrifugal fan to a state that optimizes the air volume, the blowing efficiency and the noise amount, the centrifugal fan with the optimum air volume, the blowing efficiency and the noise amount can be more easily designed. .

(14) By using a centrifugal fan with flat blades, the centrifugal fan can be designed and manufactured very easily, and the manufacturing cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an underfloor ventilation device according to a first embodiment of the present invention.

FIG. 2 is a plan sectional view of the underfloor ventilation device.

FIG. 3 is a diagram showing PQ characteristics, fan efficiency, and noise values in the underfloor ventilator in comparison with a conventional underfloor ventilator.

FIG. 4 is a diagram showing measurement results of PQ characteristics, fan efficiency, and noise value when the outer diameter of a centrifugal fan in the underfloor ventilation device is changed.

FIG. 5 is a diagram showing measurement results of a PQ characteristic, a fan efficiency, and a noise value when the inner diameter of the suction port in the underfloor ventilation device is changed.

FIG. 6 is a diagram showing measurement results of PQ characteristics and fan efficiency when the mounting angle of a blade in the underfloor ventilation device is changed.

FIG. 7 is a diagram showing measurement results of blower performance, efficiency, and noise value when the mounting angle of the blade in the underfloor ventilation device is changed.

FIG. 8 is a diagram illustrating another configuration of the centrifugal fan in the underfloor ventilation device.

FIG. 9 is a side sectional view showing a configuration of an underfloor ventilation device according to a second embodiment of the present invention.

FIG. 10 is a plan sectional view of the underfloor ventilation device.

FIG. 11 is a diagram showing a configuration of a centrifugal fan in the underfloor ventilation device.

FIG. 12 is a diagram showing another configuration of the centrifugal fan in the underfloor ventilation device.

FIG. 13 is a side sectional view showing a configuration of an underfloor ventilation device according to a third embodiment of the present invention.

FIG. 14 is a side sectional view showing a configuration of a conventional underfloor ventilation device.

FIG. 15 is a plain sectional view showing the configuration of the conventional underfloor ventilation device.

[Explanation of symbols]

 1-Underfloor 2-Suction port 3-Outside-floor 4-Outlet 5-Motor 6-Centrifugal fan 7-Fan scroll casing 8-Vent 9-Case 11-Ventilation space 16-Blade

Claims (14)

[Claims] An internal shape of a fan scroll casing which communicates with the inside of the floor at the suction port and the outside of the floor at the air outlet and which supports the centrifugal fan is constituted by an arc centered on the rotation axis of the centrifugal fan. An underfloor ventilator, characterized in that: 2. An inner diameter D of the fan scroll casing.
The underfloor ventilator according to claim 1, wherein the outer diameter of the centrifugal fan satisfies a relationship of 0.6 ≦ d1 / D ≦ 0.9, where d1 is d1. 3. An inner diameter D of the fan scroll casing.
The underfloor ventilation device according to claim 2, wherein the following formula satisfies a relationship of 0.75 ≦ d1 / D ≦ 0.85, where d1 is an outer diameter of the centrifugal fan. 4. The underfloor ventilator according to claim 1, wherein the suction port is a circular hole having a constant inner diameter in the air passage direction. 5. The underfloor ventilation according to claim 4, wherein the inside diameter d2 of the suction port satisfies the relationship of 0.3 ≦ d2 / D ≦ 0.8, where D is the inside diameter of the fan scroll casing. apparatus. 6. The underfloor ventilation according to claim 5, wherein the inside diameter d2 of the suction port satisfies the relationship of 0.4 ≦ d2 / D ≦ 0.6, where D is the inside diameter of the fan scroll casing. apparatus. 7. The centrifugal fan according to claim 1, wherein the number of blades is Z, the chord length is C, and the outer diameter is d1, and a relationship of CZ / d1 ≦ 5 is satisfied. The underfloor ventilation device as described. 8. The underfloor ventilator according to claim 7, wherein the centrifugal fan has two blades. 9. The underfloor ventilator according to claim 8, wherein the centrifugal fan is formed of a single plate. 10. The underfloor ventilator according to claim 7, wherein said centrifugal fan has three blades. 11. The centrifugal fan has an angle θ between a straight line connecting the rotation center and the inner end of the blade and a straight line connecting the inner end and the outer end of the blade. The underfloor ventilator according to any one of claims 1 to 10, wherein the case is set to be positive and the range is set to -40 ° ≤ θ ≤ 90 °. 12. The centrifugal fan has an angle θ between a straight line connecting the rotation center and the inner end of the blade and a straight line connecting the inner end and the outer end of the blade. The underfloor ventilator according to claim 11, wherein ????? 60 ??? 13. The centrifugal fan according to claim 1, wherein an angle θ between a straight line connecting the rotation center and the inner end of the blade and a straight line connecting the inner end and the outer end of the blade is 40 with respect to the case of the backward facing blade.
The underfloor ventilator according to claim 12, wherein the angle is set to °. 14. The underfloor ventilation device according to claim 1, wherein the centrifugal fan has a flat blade shape.