JP2000070595A - Clothing drying machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high labyrinth effect even when annular seals of a labyrinth seal are mutually engaged or overlapped shallowly concerning a clothing drying machine equipped with the labyrinth seal. SOLUTION: Main resistance for the labyrinth effect for increasing the channel resistance of the labyrinth seal is obtd. by shape resistance caused by the rapid alternate change of a channel cross-sectional area. As one of structures for obtaining the rapid alternate change of the channel cross-sectional area, a rapid reduction part 21a and a rapid expansion part 22a of the channel cross- sectional area or the like are alternately formed by making shallow engage depth We of annular seals 15 (15a, 15b and 15c) from a wall part 5a for fan side seal provided at the outer peripheral part of a double side fan 5 and annular seals 16 (16a, 16b and 16c) from a wall part 14a for casing side seal provided on a casing 14. Therefore even when the annular seals are mutually engaged shallowly, the high labyrinth effect can be presented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a clothes dryer, and more particularly, to a labyrinth seal in a dehumidifying clothes dryer.

[0002]

2. Description of the Related Art FIG. 27 shows a typical structural example of a conventional dehumidifying clothes dryer in a side sectional view. The clothes dryer is covered with a box-shaped housing 1, and a door 2 for taking in and out clothes to be dried is provided on the front surface thereof, and a rotary drum 4 forming a drying chamber 3 is housed inside the door 2. ing. On the other hand, a double-sided fan 5 is provided on the rear surface of the box-shaped housing 1. The two-sided fan 5 includes a hot air fan that circulates hot air 9 for drying clothes through the drying chamber 3 and a cool air fan that supplies and exhausts cooling air 10 that cools and dehumidifies the hot air 9 by heat exchange. With this configuration, it has both functions of heat exchange and air blowing, and is rotated by a motor 7 via a belt 6. The motor 7 is also a drive source for rotating the rotary drum 4.

[0003] A casing 14 is provided around the outer periphery of the double-sided fan 5 to partition the hot air 9 and the cooling air 10. Leakage of the hot air 9 to the outside and cooling between the casing 14 and the double-sided fan 5 are provided. A labyrinth seal 8 is provided for suppressing air 10 from entering the interior. The labyrinth seal 8 will be described below with reference to FIG. In FIG. 27, reference numeral 11 denotes an electric heater serving as a heating means, 12 denotes a lint filter, and 13 denotes a drain outlet for discharging collected water (condensed water).

As shown in FIG. 28, the double-sided fan 5 is provided with a fan-side sealing wall 5a on its outer peripheral portion so as to rotate integrally therewith, while the casing 14 has a fan-side sealing wall 5a. A casing-side sealing wall 14a is provided so as to face 5a. Between these, a plurality of annular seal pieces 1 provided so as to protrude from the fan-side sealing wall 5a in a concentric arrangement.
The labyrinth seal 8 is formed by a plurality of annular seal pieces 16 provided so as to protrude from the casing side sealing wall portion 14a in the same concentric arrangement. More specifically, the annular sealing pieces 15 of the fan-side sealing wall 5a and the annular sealing pieces 16 of the casing-side sealing wall 14a are alternately arranged, and the annular sealing pieces 15 and 16 from both sides are brought into contact with each other. Flow path resistance to air flow by combining non-contact in the axial direction (direction orthogonal to the radial direction) in the gap in the radial direction (concentric arrangement direction) between the annular seal pieces on the side so as to alternately bite To form a labyrinth seal 8. In FIG. 28, the hot air leaking slightly in the labyrinth seal 8 is indicated by a dotted arrow 17. Hereinafter, such a type in which the annular seal pieces from both sides are alternately arranged will be referred to as an "alternate labyrinth seal". Labyrinth seal 8
A labyrinth seal in which a plurality of annular seal pieces are arranged in the radial direction as described above is generally called a radial flow labyrinth seal.

Conventionally, a radial flow labyrinth seal as described above has utilized frictional resistance caused by fluid viscosity as a main resistance of a labyrinth effect for increasing a flow path resistance for reducing a leakage amount. For this reason, as shown in FIG. 28, the structure of the conventional labyrinth seal 8 is such that the annular seal piece 15 on the double-sided fan 5 side and the annular seal piece 16 on the casing 14 bite into each other with respect to each other. Is made deeper, thereby increasing the frictional resistance due to the viscosity of the fluid by increasing the surface area of the flow path with which the air flow contacts. Thus, the bite depth W
When the depth e is increased, the casing-side sealing wall 14
a and the width a of the gap 19 between the tip of the annular seal piece 15 on the double-sided fan 5 side and the fan-side sealing wall 5a and the casing 1
With respect to the width b of the gap 20 between the tip of the annular seal piece 16 on the fourth side, a <We and b <We are satisfied. In other words, the bite depth We is increased to increase the gap width a and the gap width b in the axial direction.
Is approximately the same as the gap width c between the annular seal pieces in the radial direction, thereby forming a gap having a substantially uniform width over the entire length of the flow path so that the flow path surface area can be as large as possible. I have.

A clothes dryer using the above-mentioned labyrinth seal by the friction resistance method is disclosed in, for example, JP-A-07-155498 and JP-A-09-108498.
An example is disclosed in Japanese Patent Publication No.

The technique disclosed in Japanese Patent Application Laid-Open No. 07-155498 is a technique for improving the fan performance of a double-sided fan by modifying the shape of the labyrinth seal. As shown in FIG. By inclining the wall 14a outward, interference with fan performance is reduced. For this reason, the annular seal piece is shortened on the side close to the rotation center of the double-sided fan, but the projecting height is gradually increased as the annular seal piece is separated therefrom. However, in this case as well, since the labyrinth effect is to be obtained by frictional resistance, the bite depth of the above-mentioned annular seal piece should be as long as possible, and the total bite depth of the entire annular seal piece should be the same as the conventional one. Is secured.

The technique disclosed in Japanese Patent Application Laid-Open No. 09-108498 is aimed at preventing condensed water from leaking to the cooling air side. There are holes etc.,
The configuration of the labyrinth seal is basically the same as the above-mentioned conventional example, and the bite depth of the annular seal piece is set as large as possible.

[0009]

As described above, in the prior art, the frictional resistance caused by the viscosity of the fluid is used as the main resistance governing the labyrinth effect for reducing the leakage amount. In other words, the basic premise is to make the bite depth of the annular seal piece as deep as possible. This has the following problems.

Generally, in the conventional clothes dryer as shown in FIG. 27, the double-sided fan 5, the casing 14, and the labyrinth seal 8 are all formed and manufactured from a synthetic resin material such as polypropylene. Therefore, during operation of the clothes dryer, the warm air 9 becomes, for example, 60 to 70 ° C., and the cooling air 10 becomes 30 ° C.
Under the condition of about -40 ° C., as shown in an example in FIG. 29, the double-sided fan 5 may warp to the side of the cooling air 10 as indicated by an arrow in the figure due to thermal deformation or the like due to a temperature difference between the front and back sides. is there. Along with this, the annular sealing piece 15 of the fan-side sealing wall portion 5a on the outer peripheral portion of the double-sided fan 5 is inclined, so that the cross-sectional area of the flow path changes, so that the flow path resistance changes, and worse. In this case, the annular seal piece 15 comes into contact with the casing 14 and the annular seal piece 16. In the figure, a black circle indicated by 50 is an example of a contact portion. Depending on the situation, other parts may come into contact.

In the case of a general clothes dryer,
The gap in the radial direction (the gap c in FIG. 28) between the annular seal pieces that bite alternately is as small as, for example, about 2 to 3 mm. Depth is for example 10
mm or more. This affects the productivity during the production and assembly of the clothes dryer. In other words, in order to avoid troubles such that the annular seal piece comes into contact with its surroundings during manufacture and assembly under the above dimensional conditions, the dimensional accuracy of the annular seal piece is increased,
In addition, it is necessary to precisely control the environmental temperature and the like at the time of manufacturing and assembling, and these are factors that impair productivity.

The present invention has been made in view of such circumstances, and relates to a clothes dryer having a labyrinth seal.
Even if thermal deformation or the like occurs on the double-sided fan during operation, the likelihood of the annular seal piece in the labyrinth seal coming into contact with the surroundings is small, and the conditions for the dimensional accuracy of the annular seal piece and the environmental temperature during manufacture and assembly are relaxed. Accordingly, it is an object of the present invention to improve the productivity by improving the labyrinth sealing performance which is equal to or higher than the conventional one.

[0013]

SUMMARY OF THE INVENTION The present invention provides a casing, a double-sided fan having a function of heat exchange and air blowing, and a cooling air provided between the casing and the double-sided fan. And a labyrinth seal that suppresses intrusion into the inside of the labyrinth, and a main resistance for a labyrinth effect that increases a flow path resistance in the labyrinth seal is a shape resistance caused by a rapid alternating change in a flow path cross-sectional area. A clothes dryer characterized by the following is disclosed.

In order to achieve the above object, according to the present invention, a warm air fan for circulating warm air for drying clothes in a drum-shaped drying chamber and cooling air for cooling and dehumidifying the warm air by heat exchange are supplied and exhausted. A cold-air fan and a double-sided fan having both functions of heat exchange and air blowing by being integrally formed on the front and back, a casing that separates the hot air and the cooling air, and also rotate integrally with the double-sided fan. Provided between a fan-side sealing wall provided on an outer peripheral portion of the double-sided fan and a stationary casing-side sealing wall provided on the casing so as to face the fan-side sealing wall. A labyrinth seal, wherein the labyrinth seal is provided with a plurality of annular seal pieces provided so as to protrude in a concentric arrangement from the fan-side sealing wall portion and the casing. A plurality of annular seal pieces provided so as to protrude from the sealing-side sealing wall in the same concentric arrangement are formed in a non-contact manner to form a flow path resistance to an air flow, and the outflow of the warm air and the It is assumed that the inflow of cooling air is suppressed, and that the main resistance for the labyrinth effect of increasing the flow path resistance in the labyrinth seal is a shape resistance caused by a rapid alternating change in the flow path cross-sectional area. Features.

The configuration of the present invention as described above makes the concept of the labyrinth effect in the labyrinth seal completely different from the conventional one. That is, while the main controlling factor of the flow path resistance in the labyrinth seal of the conventional clothes dryer was the friction resistance caused by the viscosity of the fluid, in the present invention, the abrupt alternation of the flow path cross-sectional area caused the air to flow. The shape resistance caused by the rapid expansion and contraction of the flow alternately is used. That is, in the present invention, the decelerating flow and the accelerating flow, which greatly change into the air flow, are alternately generated by changing the cross-sectional area of the flow path abruptly and alternately several times along the flow direction of the fluid. The main resistance for the labyrinth effect is obtained by generating a large number of unstable small vortices to increase the flow path resistance.

The use of the shape resistance as the main resistance for the labyrinth effect is not limited to the conventional "alternate labyrinth seal", but to the "opposite one-side labyrinth seal". It is also possible.

In the case of the "alternate labyrinth seal", each of the annular seal pieces of the fan-side seal wall and the respective annular seal pieces of the casing-side seal wall are connected to each other by the annular seals. The pieces are arranged so as to bite into the gaps in the concentric arrangement direction alternately. Then, the cut-in depth We of the annular seal pieces in the axial direction, the gap width a between the tip of the annular seal piece of the fan-side seal wall and the casing-side seal wall, and the width of the casing-side seal wall. Regarding the gap width b between the tip of the annular seal piece and the fan-side sealing wall, We ≦ a and / or We ≦ b
By doing so, abrupt alternation of the flow path cross-sectional area is caused.

As described above, giving a specific relationship between the bite depth We and the gap width a or the gap width b in order to cause the rapid expansion and contraction of the air flow requires the gap width a and the gap width b.
Width c in the concentric arrangement direction of the annular seal pieces
Is substantially the same as giving a specific relationship with respect to And in the case of the latter, the general
Assuming a gap width c of 3 mm, the gap width a and the gap width b are preferably at least 1.5 c in order to effectively obtain the shape resistance due to the rapid expansion and contraction of the air flow.

Therefore, the "alternate labyrinth seal"
In this case, each annular sealing piece of the fan-side sealing wall and each annular sealing piece of the casing-side sealing wall,
Arranged so as to alternately bite into the gap in the concentric arrangement direction of the annular seal pieces of each other and
The gap width a between the tip of the annular sealing piece of the fan-side sealing wall and the casing-side sealing wall, and the gap width between the tip of the annular sealing piece of the casing-side sealing wall and the fan-side sealing wall. Regarding the gap width b and the gap width c in the concentric arrangement direction of the annular seal pieces that bite into each other, by setting a ≧ 1.5c and / or b ≧ 1.5c, the flow path cross-sectional area can be sharply increased. Alternating changes can also occur.

On the other hand, in the case of the "opposite piece type labyrinth seal", each annular seal piece of the fan-side sealing wall and each annular seal piece of the casing-side sealing wall are respectively opposed to each other. The annular seal pieces are arranged such that their end faces face each other. Then, the position of the gap between the tips of the opposed annular seal pieces is shifted in accordance with the concentric arrangement of the annular seal pieces, thereby causing a rapid alternating change in the flow path cross-sectional area.

Such an "opposite piece labyrinth seal"
In the case of, the position of the gap between the tips of the opposed annular seal pieces is shifted according to the concentric arrangement of the annular seal pieces, whereby the annular seal piece of the fan-side seal wall and the casing-side seal wall are The overlap depth that occurs between the annular seal piece and the overlapping depth when the deformation expected in a normal use condition occurs in a double-sided fan, a casing, or the like, the overlap depth is adjacent in the arrangement direction of the annular seal piece. In the range that does not become negative between the other annular seal pieces,
By making it as small as possible, a greater labyrinth effect can be produced.

In the case of the above-mentioned "opposite piece labyrinth seal", the width A of the gap between the tips of the opposed annular seal pieces and the width of the gap in the concentric arrangement direction of the annular seal pieces are set. With respect to B, by setting A ≦ B, a greater labyrinth effect can be generated.

In each of the "alternate piece labyrinth seal" and the "opposite piece labyrinth seal" mainly composed of the shape resistance, the gap through which the hot air flow to flow out first passes through the gap in the flow path thereafter. It is effective to make the width narrower than any of the above. Therefore, a gap formed between the tip of the annular seal piece and the casing-side sealing wall or the fan-side sealing wall formed by the first annular sealing piece with respect to the outflow direction of the hot air, or between the leading ends of the annular seal pieces. The gap between the tip of the annular seal piece and the casing-side sealing wall or the fan-side sealing wall, or the gap between the tips of the annular seal pieces, which is formed by another annular sealing piece. More preferably, it is narrowed.

As described above, the main resistance for the labyrinth effect is obtained from the abrupt alternation of the cross-sectional area of the flow path, that is, the shape resistance caused by the alternating rapid reduction and rapid expansion of the air flow. Even if the bite depth of the annular seal piece (in the case of "alternate labyrinth seal") or the overlap depth (in the case of "opposite labyrinth seal") is shallow, labyrinth seal performance equal to or greater than that of the conventional type can be achieved. Can be demonstrated. As a result, it is possible to solve the above-mentioned various problems in the conventional labyrinth seal while exhibiting the labyrinth seal performance equal to or higher than the conventional one. That is, even if the double-sided fan or the like is warped due to thermal deformation or the like due to the temperature difference between the hot air and the cooling air, the flow path resistance does not change significantly, and more stable labyrinth sealing performance can be obtained. Further, the possibility that the annular sealing piece contacts the surroundings and causes a failure can be significantly reduced. Furthermore, the dimensional accuracy of the annular seal piece and the control conditions for the environmental temperature during production and assembly can be relaxed, and the productivity can be improved.

[0025]

Embodiments of the present invention will be described below. FIG. 1 shows an enlarged cross section of a labyrinth seal portion in the clothes dryer according to the first embodiment. The labyrinth seal 8 in the present embodiment is an “alternate piece labyrinth seal”, and as shown in FIG.
Three annular seal pieces 15 (15a, 15b, 15c) projecting concentrically from the fan-side sealing wall 5a
And three annular sealing pieces 16 (16a, 1a) protruding from the casing side sealing wall 14a in the same concentric arrangement.
6b, 16c) are arranged alternately, and the annular seal pieces 15 and 16 from both sides are placed in the gap in the radial direction (concentric arrangement direction) between the other annular seal pieces in the axial direction (the radial direction and the radial direction). (In the direction orthogonal to each other), and are formed so as to be in contact with each other without contact. The penetration depth We between the annular seal pieces (the annular seal piece 15b in the figure)
Only the bite depth of the annular seal piece 16c that has cut into the gap between the annular seal piece 15c)
In relation to the width a of the gap 19 between the casing-side sealing wall 14a and the tip of the fan-side annular seal piece 15, "We
≦ a ”. By reducing the bite depth We in this way, it is possible to reduce the possibility that the annular seal pieces come into contact with each other when the double-sided fan 5 or the like is deformed, and also to improve the productivity during production and assembly. Can be improved. In the example of the figure, only the gap width a is made larger than the biting depth We, and the width b of the gap 20 between the fan-side sealing wall 5a and the casing-side annular sealing piece 16 is smaller than the biting depth We. However, if necessary, the gap width b is set to be larger than the bite depth We.

Due to the pressure difference between the hot air 9 and the cooling air 10, for example, air leaking from the hot air 9 flows into the labyrinth seal 8 as shown by an arrow 17a. The leaked air that has flowed in this way is first removed from the annular seal pieces 15a and 16a.
The flow into the rapid reduction portion 21a of the flow path cross-sectional area due to the radial gap formed by the flow path a generates an accelerated flow and receives a large flow resistance, and then the annular seal piece 15a and the casing-side sealing wall 14a. The fluid flows into the abruptly enlarged portion 22a of the cross-sectional area of the flow channel due to the formed axial gap, and then receives a large flow channel resistance by generating a deceleration flow. In the same manner as described above, similarly, the suddenly decreasing portion (21b etc.) and the suddenly increasing portion (2
2b) alternately, each time a large flow path resistance is received. The pressure loss due to such a rapid and alternating change in the flow path cross-sectional area, that is, a rapid contraction flow and a rapid expansion flow, is large. In the present embodiment, this alternate change is repeated three times, but a sufficiently large flow path resistance is generated even with this repetition. Therefore, it is possible to effectively prevent the hot air 9 from leaking out as hot air and flowing out to the outside and the cooling air 10 flowing into the inside.

The labyrinth seal according to the second embodiment shown in FIG. 2 is a modification of the first embodiment. In the first embodiment, the casing side sealing wall 14a extends in the radial direction (vertical direction in the figure). In the present embodiment, the casing-side sealing wall portion 14a is set upright, while being inclined.

Here, a description will be given of an experiment for examining the channel resistance due to the rapid contraction flow and the rapid expansion flow while changing the bit depth We to optimize the depth. FIG. 3 shows the results of an experiment using the seal model device. The horizontal axis represents the average flow velocity of air flowing through the duct D (corresponding to the amount of leakage), and the vertical axis represents the pressure loss (flow) measured before and after the labyrinth seal. Road structure), a large labyrinth effect seal structure,
That is, the data is located at the top of the figure as the seal structure has a larger flow path resistance. The numerical values of the model device are shown in the upper left of the figure. The deepest bite depth We = 10mm
When the bite depth is gradually reduced from the state of (the projection length of the annular seal piece X = 15 mm), the pressure loss also gradually increases, and the labyrinth effect is improved. Then, the pressure loss becomes maximum at the bite depth We = 0 mm (X = 5 mm), that is, where the tip positions of the annular seal pieces facing each other coincide. If the length X of the annular seal piece is further reduced (for example, X = 2.5 mm), the bite depth We becomes negative (We = -2.5 mm), and an obstacle in the flow direction is formed between the tips of the annular seal pieces facing each other. There is no gap. In this case, an air blow-through phenomenon occurs,
The pressure loss is drastically reduced.

From the experimental results, the bite depth applied to the "alternate labyrinth seal" of the present invention is We = 0.
Although a range of 10 mm to 10 mm can be considered to be almost suitable, a more preferable range is a range of We = 0 mm to 2.5 mm. That is, from the experimental results, the pressure loss is maximum at We = 0 mm, and it is optimal to set We = 0 mm theoretically. However, the assembly error at the time of manufacture and assembly and the deformation of the double-sided fan 5 during operation are considered. Then, it is necessary to give a margin. That is, as factors of the deformation of the double-sided fan 5 and the like, there are, for example, thermal deformation due to a temperature difference between hot air and cooling air, and swelling deformation of the double-sided fan 5 due to oil components attached to clothes to be dried. If the double-sided fan 5 or the like is configured so as to be highly stable with respect to the factors and substantially neglect the deformation, apart from the assembling error, the penetration depth We is substantially equal.
= 0 mm is optimal. On the other hand, if a certain degree of deformation or assembly error is to be expected, when such an event occurs, the bite depth should be reduced in order to prevent the bite depth from becoming a negative value of 0 or less and causing the above-described blow-by phenomenon. Allow room for depth. In the case of a conventional general clothes dryer, the degree is up to about 2.5 mm,
At worst, it can be estimated to be about 5 mm.

The magnitude of the bite depth as described above can be understood from another viewpoint. That is, the bite depth is the size of the width a of the gap 19 and the width b of the gap 20 formed by the annular sealing pieces 15 and 16 between the casing-side sealing wall 14a and the fan-side sealing wall 5a. Making the bite depth as shallow as 0 to 2.5 mm is the same as increasing the gap widths a and b.
On the other hand, the width c of the gap in the radial direction between the annular seal pieces that bite into each other is naturally determined by a condition that is not directly related to these. The rapid reduction or rapid expansion of the flow channel cross-sectional area is given by the size relationship between the gap widths a and b and the gap width c. It can be defined as the relationship between a and b and the gap width c. The specific numerical values are as follows, assuming that the gap width c in a general clothes dryer is usually about 2 to 3 mm, and based on the above experimental results, a
≧ 1.5c or b ≧ 1.5c, or a ≧ 1.5c and b ≧ 1.5
It can be said that any one of c is satisfied. However, this is the minimum condition, and more preferable conditions in practice are a ≧ 2c or b ≧ 2c, or a ≧ 2c and b ≧ 2
It can be said that any one of c is satisfied.

Next, in order to support and consider the results shown in FIG. 3, the results of flow visualization experiments are shown in FIG. The model device is the same as in FIG. 3, the air flows from left to right and the tracer is incense smoke. The upper part of FIG. 4 has the deepest penetration depth We = 10 mm (X = 15 m
m; see the upper left of FIG. 3), the lower part is a case where the bite depth is relatively shallow We = 2.5 mm (X = 7.5 mm), and a schematic diagram of the flow drawn based on the visualized photograph is shown.
In the case where the bite depth We in the upper part of the figure is deep and the gap is narrow, the flow of air is smooth and almost no vortex is observed, and it is considered that the flow resistance is mainly caused by frictional resistance. On the other hand, the penetration depth We in the lower part of the figure is
When the air flow is shallow and the gap is wide, the air flow repeats a rapid expansion flow and a rapid contraction flow, each time a large number of unstable small vortices are observed. It is well understood that the flow resistance mainly caused by the shape resistance such as the above is mainly used. This result indicates that the labyrinth seal structure of the present invention conforms to the concept of the flow path resistance of the present invention. From the visualization result of the experiment in FIG. 4, the flow of the leaked hot air in the labyrinth seal 8 of the present invention shown in FIG. 1 is estimated as shown in FIG. The large flow resistance caused by the shape resistance due to the large vortex 23a and the small vortex 23b due to the rapid expansion flow and the rapid contraction flow, that is, the good labyrinth effect causes the leakage of the warm air and the intrusion of the cooling air to be the same as the conventional one. Or more.

Hereinafter, another embodiment of the "alternate labyrinth seal" in the present invention will be described. The third embodiment shown in FIG. 6 is a case where the labyrinth effect has the best bite depth We ≒ 0 mm obtained from the experimental results of FIG. 3, and the gap width in the axial direction according to We ≒ 0 mm. a
And b are the widest. This condition is ideal for the labyrinth effect. However, as described above, when the double-sided fan 5 is deformed or the like, the biting depth becomes a negative value, and there is a concern that a blow-by phenomenon may occur. Therefore, the present embodiment is suitable for a case where there is no possibility of substantial deformation occurring in the double-sided fan 5 or the like. Otherwise, the minimum required in consideration of a deformation or the like that may occur in the double-sided fan 5 or the like. The depth of penetration.

The fourth embodiment shown in FIG. 7 is an example in which a predetermined digging depth We is provided so as not to be larger than any of the gap widths a and b in the axial direction. a and We ≦ b. Here, the relationship of We ≦ a and We ≦ b in the present embodiment and We ≦ a in the first embodiment is basically applied to all of the plurality of annular seal pieces forming the labyrinth seal. Although desirable, it can be applied to only a part of the annular sealing piece, and even in this case, it does not depart from the spirit of the present invention.

In the fifth embodiment shown in FIG. 8, the first annular seal piece 16a in the flow direction of the leaked hot air (indicated by the arrow 17a) is the opposite annular seal piece 15a.
The width c1 of the gap 24a in the radial direction formed therebetween is particularly narrowed. That is, the gap width c1 is changed to the widths c2 to c of the other gaps.
5 is narrower than any of 5. Naturally, these radial gaps are narrower than the widths a and b of the gaps in the axial direction from the above-mentioned conditions of a ≧ 1.5c and b ≧ 1.5c. Making the gap formed by the first annular seal piece narrowest as compared with the other gaps is effective for further enhancing the labyrinth effect. This is derived from the above series of experimental results. That is, from the above series of experiments, it was found that narrowing the gap between the annular seal pieces located first in the air flow direction among the plurality of annular seal pieces greatly contributed to the increase in the flow path resistance. . In other words, it is effective for the labyrinth effect to make the first gap narrowest among a plurality of gaps included in the labyrinth seal, which narrows the gap at the middle part of the labyrinth seal and the last gap. It is more effective than doing. Reducing the gap of the first annular seal piece by this is also reasonable with respect to the problem of contact between the annular seal pieces due to deformation of the double-sided fan 5. In other words, the influence of the deformation of the double-sided fan 5 generally occurs in the labyrinth seal as shown in FIG. 29. As can be seen from this, even if the width c1 of the gap 24a is reduced, the annular seal pieces are not deformed due to the deformation. It does not increase the possibility of contact.

In the sixth embodiment shown in FIG. 9, the same concept as that of the fifth embodiment is adopted.
6a is applied to the width b1 of the axial gap 20a. In this case, the same effect as that of the fifth embodiment can be expected.

Although all of the embodiments described above relate to the "alternate labyrinth seal", an embodiment relating to the "opposite labyrinth seal" of the present invention will be described below. Labyrinth seal 8 in seventh embodiment
As shown in FIG. 10, three annular seal pieces 15 projecting concentrically from the fan-side sealing wall 5a.
(15a, 15b, 15c) and three annular seal pieces 16 (16a, 16b, 16c) protruding from the casing-side sealing wall 14a in the same concentric arrangement, respectively, with the other annular seal pieces. Are arranged to face each other, and the positions of the gaps 40 between the tips of the opposed annular seal pieces are alternately shifted in accordance with the concentric arrangement of the annular seal pieces. Therefore, the gap 40
Suddenly expanding portions 42a, 4a due to the radially-spaced portions between the rapidly reducing portions 41a, 41b, 41c and the annular seal pieces.
2b are formed alternately.

FIG. 11 shows a result of an experiment of visualizing an air flow in a model corresponding to the present embodiment, and shows a schematic diagram of a flow similar to that in the “alternate labyrinth seal” shown in FIG. Air flows from left to right. The air flow repeats a rapid expansion flow and a rapid contraction flow, and each time a large number of small vortices are observed in the corners, the flow caused by the shape resistance of the rapid expansion flow, the rapid contraction flow, and the vortex It can be clearly understood that the road resistance is effective. This result indicates that the opposing single-piece labyrinth seal structure also conforms to the concept of the present invention.

In the eighth embodiment shown in FIG. 12, the fan-side sealing wall 5a and the casing-side sealing wall 14a
In each of the four annular seal pieces 15 (15a, 15a).
b, 15c, 15d) and the annular seal piece 16 (16a, 1
6b, 16c and 16d), and the overlapping depth Wr of the annular seal piece 15 from the fan side and the annular seal piece 16 from the casing side is made smaller than that in the embodiment of FIG. Here, as shown in FIG. 10 and FIG. 12, the overlap depth Wr relates to the overlap between adjacent annular seal pieces in the arrangement direction of the annular seal pieces. That is, in FIG.
5d and the annular seal 16c, the annular seal 16c and the annular seal 15b, and the annular seal 15b and the annular seal 16a overlap with each other. However, in FIG. 12, the overlap depth Wr is shown only for the overlap between the annular seal pieces 15d and 16c. Reducing the overlapping depth corresponding to the bite depth in the "alternate labyrinth seal" in this way is effective in increasing the labyrinth effect also in the "opposite labyrinth seal" from an experiment similar to FIG. I know that That is, also in the “opposite piece labyrinth seal”, the flow path resistance can be further increased by reducing the overlapping depth (approaching Wr = 0 mm).
Also, reducing the overlapping depth is effective in the "opposite piece labyrinth seal" as well as in the contact problem of the annular seal pieces as in the "alternate piece labyrinth seal".

A labyrinth seal according to a ninth embodiment shown in FIG. 13 is a modification of the eighth embodiment. In the eighth embodiment, the casing side sealing wall 14a extends in the radial direction (vertical direction in the figure). In the present embodiment, the casing-side sealing wall portion 14a is set upright, while being inclined.

Here, the gap 40 between the tips of the opposed annular seal pieces is equal to the number of annular seal pieces provided on the fan-side sealing wall 5a and the casing-side sealing wall 14a. Where the width A of each gap is
They may be the same or different. In general, it is preferable to reduce the width of the gap as much as possible within a range in which there is no possibility that the annular seal pieces come into contact with each other in consideration of a safety factor against molding errors and assembly errors of members related to the labyrinth seal portion. I can say. In addition, the number of annular seal pieces is determined according to the amount of leakage (outflow amount) of hot air to be suppressed and the amount of inflow of cooling air. Therefore, when a higher labyrinth effect is required, unlike the seventh to ninth embodiments in which the number of annular seal pieces is three or four, the labyrinth seal in the tenth embodiment shown in FIG. 5 or more. However, it is generally desirable to minimize the number of annular sealing pieces. It is needless to say that the amount of leakage to be suppressed can be controlled not only by the number of annular seal pieces but also by the flow path cross-sectional area of each gap, the pressure difference between hot air and cooling air, and the like.

FIG. 15 shows a labyrinth seal according to the eleventh embodiment. In the present embodiment, the tips of the annular seal pieces 15 and 16 are inclined. It is also known from a series of experimental results that the flow path resistance increases in this manner. It is more preferable that the direction of the inclination is opposite to the direction in which the leaked hot air flows. More preferably, the inclination is provided on both of the opposed annular seal pieces.

In the twelfth embodiment shown in FIG. 16, for the same reason as in the fifth embodiment relating to the "alternate labyrinth seal", the flow direction of the leaked hot air (arrow 1).
7a), the first annular sealing piece 16
The width B1 of the radial gap 24a formed between the annular seal piece 15a and the annular seal piece 15a that overlaps the width a1 is smaller than any of the radial gaps c2 to c4 of the other annular seal pieces. . In this case, there is no problem regarding the possibility of contact between the annular seal pieces due to deformation of the double-sided fan 5 as in the fifth embodiment.

The thirteenth embodiment shown in FIG.
In the modification of the embodiment, the width A1 of the first gap 40a between the annular seal pieces is changed to the width (A2, A3, A4, A4) of the gap (40b to 40d) between the other annular seal pieces.
It is narrower than any of 5).

The fourteenth embodiment shown in FIG. 18 is an example in which the gap between the annular sealing pieces is relatively narrow. That is, the width A of the opposed gap 40 is smaller than the width B of the gap in the radial direction between the annular seal pieces. Reducing the width A of the opposing gap 40 as in the present embodiment is effective in enhancing the labyrinth effect in the "opposite piece labyrinth seal". However, as described above, since there are problems such as molding errors and assembly errors of members related to the labyrinth seal portion, the width of the gap is as small as possible so that there is no possibility that the annular seal pieces may come into contact with each other in consideration of a safety factor against them. It can be said that it is preferable to make In general, this means that the width A of the opposed gap 40 satisfies the relationship of A ≦ B in comparison with the width B of the gap in the radial direction between the annular seal pieces. In the present embodiment, the overlapping depth happens to be increased. However, as described above, it is effective to reduce the overlapping depth as much as possible for the labyrinth effect in the present embodiment.

Generally, each member such as a double-sided fan and a casing related to a labyrinth seal of a clothes dryer is often formed and manufactured from a synthetic resin material such as polypropylene. Therefore, when a clothes dryer is frequently used to dry clothes containing oil components, the oil components impregnate the synthetic resin material and swell it, causing deformation of the double-sided fan and casing, resulting in labyrinth seals. May cause contact between the annular seal pieces. Several approaches are possible to address such problems. One is a method in which an exposed surface of a double-sided fan or a casing that comes into contact with air, particularly an exposed surface that may come into contact with an oil component from clothing to be dried, is thinly coated with a material having no oil component impregnation. . An example of a labyrinth seal according to this method is shown in FIG. 19 as a fifteenth embodiment. In this example, the thin coating layer 25 is made of a synthetic resin or the like which does not contain a rubber component which causes impregnation of an oil component.
4, and the associated annular sealing pieces 15 and 16 are formed on the exposed surfaces. It is more preferable that the coating layer 25 be made of a material that does not impregnate the oil component and that its surface be hydrophilic. For this purpose, it is preferable that the coating layer 25 is formed of a material which has both the property of not impregnating the oil component and the hydrophilic property.

Another one is to form the double-sided fan 5 and the casing 14 from a material which is not impregnated with an oil component or which does not swell due to the oil component. In this case, a metal material such as aluminum or magnesium may be used in addition to the synthetic resin material. Also in this case, in addition to the material not impregnated with the oil component, it is more preferable that the surface is hydrophilic as described above.

Next, some examples of preferred shapes of the annular seal pieces for practicing the present invention will be described. The annular seal pieces 15 and 16 whose cross sections are shown in FIG. 20 are tapered on both side surfaces 26, and the annular seal pieces 15 and 16 whose cross section is shown in FIG. The annular seal pieces 15 and 16 whose cross sections are shown in FIG. 22 are cut in two directions so that the center of the tip 27 projects at an acute angle, and the annular seal pieces 15 and 16 whose cross section is shown in FIG. 22 are cut in such a manner that both ends of the tip 27 project at an acute angle and are provided with recesses in the center, and the annular seal pieces 15 and 16 whose cross sections are shown in FIG. A plurality of irregularities 28 arranged in a direction
Further, the annular seal pieces 15 and 16 shown in FIG. 25 as viewed from the front thereof are provided with a plurality of irregularities 28 arranged in the circumferential direction. Any of these shapes can increase the flow path resistance in accordance with the characteristics of each of them, so that it is appropriate to appropriately use them. These shapes can be used in combination as appropriate.

In the labyrinth seal according to the present invention as described above, the main resistance for the labyrinth effect is obtained from the shape resistance caused by the alternate rapid expansion and contraction of the air flow. And the overlapping depth can be made shallow, so that even if the double-sided fan warps due to thermal deformation or the like, the influence thereof can be reduced. However, the warpage of a double-sided fan would not be better if it did not occur. Therefore, taking measures against warpage that may occur due to thermal deformation etc. on the double-sided fan
It is even more preferred. FIG. 26 shows an embodiment relating to one example. As can be seen in FIG. 26, the double-sided fan 5 includes a number of blades 29 which also serve as heat exchange fins,
A labyrinth seal 8 is provided on the outer peripheral portion. In this embodiment, four elongated reinforcing members 30 are attached to the two-sided fan 5.
Is installed. Each reinforcing member 30 is attached by fixing one end to a pulley 31 generally formed of a highly rigid metal and fixing the other end to a fan-side sealing wall 5 a for the labyrinth seal 8. It is desirable that the reinforcing member 30 has high rigidity. For this reason, the reinforcing member 30 is formed of a material having high rigidity, or is provided with an appropriate cross-sectional shape so that high rigidity can be obtained. In addition to the addition of the reinforcing member, the wing 2 of the double-sided fan 5
9 can be made to have a high rigidity that is not easily deformed by heat, and the double-sided fan 5 can be made of a material having a small coefficient of thermal expansion (linear expansion coefficient). It is more preferable to carry out.

[0049]

According to the labyrinth seal of the present invention, the main resistance for the labyrinth effect is obtained by the shape resistance due to the rapid change of the cross-sectional area of the flow path, so that it is the same as the conventional one. In order to exhibit the labyrinth sealing performance equal to or greater than that, the bite depth and overlap depth of the annular seal piece can be reduced. For this reason, while exhibiting labyrinth sealing performance equal to or higher than the conventional one, it is necessary to improve stability against problems such as changes in flow path resistance and contact between annular seal pieces when deformation of a double-sided fan etc. occurs. In addition, it is possible to improve the productivity by relaxing the conditions for controlling the environmental temperature during production and assembly.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a labyrinth seal according to a first embodiment.

FIG. 2 is a side sectional view of a labyrinth seal according to a second embodiment.

FIG. 3 is a diagram illustrating a relationship between a biting depth and a pressure loss.

FIG. 4 is a visualization diagram of a flow in the model device.

FIG. 5 is a diagram showing an estimated flow of the labyrinth seal of FIG. 1;

FIG. 6 is a side sectional view of a labyrinth seal according to a third embodiment.

FIG. 7 is a side sectional view of a labyrinth seal according to a fourth embodiment.

FIG. 8 is a side sectional view of a labyrinth seal according to a fifth embodiment.

FIG. 9 is a side sectional view of a labyrinth seal according to a sixth embodiment.

FIG. 10 is a side sectional view of a labyrinth seal according to a seventh embodiment.

FIG. 11 is a visualization diagram of a flow in the model device.

FIG. 12 is a side sectional view of a labyrinth seal according to an eighth embodiment.

FIG. 13 is a side sectional view of a labyrinth seal according to a ninth embodiment.

FIG. 14 is a side sectional view of a labyrinth seal according to a tenth embodiment.

FIG. 15 is a side sectional view of a labyrinth seal according to an eleventh embodiment.

FIG. 16 is a side sectional view of a labyrinth seal according to a twelfth embodiment.

FIG. 17 is a side sectional view of a labyrinth seal according to a thirteenth embodiment.

FIG. 18 is a side sectional view of a labyrinth seal according to a fourteenth embodiment.

FIG. 19 is a side cross-sectional view of a labyrinth seal according to an embodiment covering an exposed surface.

FIG. 20 is a side sectional view of an annular seal piece.

FIG. 21 is a side sectional view of an annular seal piece.

FIG. 22 is a side sectional view of an annular seal piece.

FIG. 23 is a side sectional view of an annular seal piece.

FIG. 24 is a side sectional view of an annular seal piece.

FIG. 25 is a front view of an annular seal piece.

FIG. 26 is a perspective view of a double-sided fan having a reinforcing member.

FIG. 27 is a side sectional view of a conventional clothes dryer.

FIG. 28 is a side sectional view of a conventional labyrinth seal.

FIG. 29 is a diagram showing a state of contact between annular seal pieces in a conventional labyrinth seal.

[Explanation of symbols]

 Reference Signs List 3 Drying chamber 4 Rotary drum 5 Double-sided fan 8 Labyrinth seal 9 Hot air 10 Cooling air 14 Casing 15 Fan-side annular seal piece 16 Casing-side annular seal piece 19 Axial gap 20 Axial gap 21a Abrupt reduction portion 22a Enlarged part 24 Radial gap 40 Axial gap

Continuing from the front page (72) Inventor Tsuneshi Komatsu 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Hitachi, Ltd.Electrical Equipment Division (72) Inventor Keijiro Yagi, Higashi Taga-machi, Hitachi City, Ibaraki Prefecture 1-1-1 Cita Headquarters, Hitachi, Ltd.Electrical Equipment Division, Hitachi, Ltd. (72) Inventor Hideaki Munegata 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture F-term in the Taga Headquarters, Hitachi, Ltd. (Reference) 4L019 AA02 AB04 AE03 AF04

Claims (8)

[Claims] 1. A casing, a double-sided fan having functions of heat exchange and air blowing, and provided between the casing and the double-sided fan to suppress leakage of hot air to the outside and entry of cooling air into the inside. Clothing comprising a labyrinth seal, and wherein a main resistance for a labyrinth effect for increasing a flow path resistance in the labyrinth seal is a shape resistance caused by a rapid alternating change in a flow path cross-sectional area. Dryer. 2. A hot air fan for circulating warm air for drying clothes into a drum-shaped drying chamber and a cool air fan for supplying and discharging cooling air for cooling and dehumidifying the warm air by heat exchange are integrally formed. A double-sided fan having both functions of heat exchange and air blowing, a casing for partitioning the warm air and the cooling air, and provided on an outer peripheral portion of the double-sided fan so as to rotate integrally with the double-sided fan. And a labyrinth seal provided between the stationary casing-side sealing wall portion provided in the casing so as to face the fan-side sealing wall portion and the fan-side sealing wall portion. The labyrinth seal includes a plurality of annular seal pieces provided so as to protrude in a concentric arrangement from the fan-side sealing wall and the casing-side sealing wall. By combining a plurality of annular seal pieces provided so as to project in an array in a non-contact manner, a flow path resistance to an air flow is formed to suppress the outflow of the warm air and the inflow of the cooling air, and A clothes dryer characterized in that a main resistance for a labyrinth effect for increasing a flow path resistance in the labyrinth seal is a shape resistance resulting from a rapid alternating change in a flow path cross-sectional area. 3. A gap in a concentric arrangement direction between the respective annular seal pieces of the fan side seal wall and the respective annular seal pieces of the casing side seal wall. Arranged so that they bite into each other, and
Depth We of the annular seal pieces in the axial direction in the axial direction, gap width a between the tip of the annular seal piece of the fan-side sealing wall and the casing-side sealing wall, and annular shape of the casing-side sealing wall. Regarding the gap width b between the tip of the seal piece and the fan-side sealing wall, We ≦ a and / or We
3. The clothes dryer according to claim 2, wherein abrupt alternation of the flow path cross-sectional area is caused by setting ≦ b. 4. 4. The annular sealing pieces of the fan-side sealing wall and the annular sealing pieces of the casing-side sealing wall are respectively formed in gaps in the concentric arrangement direction of the other annular sealing pieces. The width a of the gap between the tip of the annular sealing piece of the fan-side sealing wall and the casing-side sealing wall, and the tip of the annular sealing piece of the casing-side sealing wall are arranged so as to bite alternately. With respect to the width b of the gap between the fan-side sealing wall and the width c of the gap in the concentric arrangement direction of the annular seal pieces that bite into each other, a ≧ 1.5c and / or b ≧ 1.5c. The clothes dryer according to claim 2, wherein abrupt alternation of the cross-sectional area of the flow path is caused by the above. 5. The annular seal pieces of the fan-side seal wall and the annular seal pieces of the casing-side seal wall are arranged such that their respective end faces face each other with the annular seal pieces on the other side. And the gap between the tips of the opposed annular seal pieces is shifted according to the concentric arrangement of the annular seal pieces, thereby causing a rapid alternating change in the flow path cross-sectional area. Item 3. A clothes dryer according to item 2. 6. The annular sealing piece of the fan-side sealing wall and the casing-side sealing wall by shifting the position of the gap between the tips of the opposed annular sealing pieces according to the concentric arrangement of the annular sealing pieces. The overlap depth that occurs between the annular seal piece and the overlapping depth when the deformation expected in a normal use condition occurs in a double-sided fan, a casing, or the like, the overlap depth is adjacent in the arrangement direction of the annular seal piece. 6. The clothes dryer according to claim 5, wherein the size of each of the other annular seal pieces is as small as possible without being negative. 7. The width A of the gap between the tips of the opposed annular seal pieces and the width B of the gap in the concentric arrangement direction of the annular seal pieces are such that A ≦ B.
Or the clothes dryer according to claim 6. 8. A gap formed between an end of the annular seal piece and a casing-side sealing wall or a fan-side sealing wall, or an annular seal piece, which is formed by an annular sealing piece located first with respect to a hot air outflow direction. The gap between the tips of the two is formed by another annular seal piece, the gap between the tip of the annular seal piece and the casing-side sealing wall or the fan-side sealing wall, or between the tips of the annular seal pieces. The clothes dryer according to any one of claims 3 to 7, wherein the clothes dryer is configured to be narrowest with respect to the gap.