Fan filter unit

Abstract

To reduce an operation sound in a fan filter unit.SOLUTION: A fan filter unit comprises: a fan part that is a case storing a fan runner for generating an air flow by being driven by a motor; a filter part that is a case containing a filter for filtering foreign bodies contained in the air flow generated by the fan runner; a first sound insulating board located between the fan part and the filter part, installed in nearly parallel with a rotation surface of the fan runner, and for diffusing the air flow generated by the fan runner; and a silencing part that is a case storing a second sound insulating board not overlapping with the first sound insulating board and the rotation surface of the fan runner in a vertical direction, and for collecting the air flow diffused by the first sound insulating board.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to the operating noise of fan filter units (hereinafter abbreviated as FFU) used in the medical field and industrial fields such as semiconductor manufacturing to control room pressure and ensure cleanliness in clean booths. [Background technology]

[0002] In various fields such as the medical field and semiconductor manufacturing, work that requires high air purity is often carried out in clean spaces such as clean booths. FFUs are used to ensure the cleanliness of the air inside the clean booth.

[0003] The FFU is equipped with a fan runner that supplies air, a motor that rotates the fan runner, and a filter that converts contaminated air into purified air. As the fan runner rotates, it generates wind and the purified air that has passed through the filter is supplied to the secondary side.

[0004] Because the noise generated by the fan runner and motor is constant within the enclosed space, coupled with the sound reverberating within the room, there are concerns that this could have a negative impact on the health of workers in the clean booth.

[0005] Patent Document 1 discloses an air cleaner with a resonator, which includes an air cleaner, a resonance chamber, and a duct, and in which the resonance chamber and the duct are connected to form a resonator.

[0006] Patent Document 2 discloses a sound insulation device consisting of multiple semicircular shielding plates fixed to the inner wall of a cylinder at intervals in the direction of noise flow, alternately at the upper limit, and in the diameter direction, with sound-proofing material attached to the inner walls of the cylinder and the shielding plates. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] 4-59363 [Patent Document 2] Actual publication Showa 60-125442 Summary of the Invention [Problem to be solved by the invention]

[0008] In clean booths, the FFU needs to be operated continuously to maintain room pressure and cleanliness.

[0009] As a result, the wind noise caused by the fan runner and the motor noise are constantly generated.

[0010] Common methods for reducing noise from FFUs include installing sound-absorbing material on the primary side of the filter and installing a shield to insulate the sound. In the former case, the clean booth may need to be sterilized in some cases, and the chemicals used may cause the sound-absorbing material to deteriorate. In the latter case, the air volume tends to decrease because noise and air volume are proportional to each other, so noise reduction must be performed using only sheet metal structures without decreasing the air volume. The object of the present invention is to reduce the noise from FFUs. [Means for solving the problem]

[0011] The above objective is achieved by a fan filter unit comprising a fan section which is a housing that houses a fan runner that is driven by a motor and creates an airflow; a filter section which is a housing that contains a filter that filters out foreign matter contained in the airflow created by the fan runner; a first sound-proofing plate located between the fan section and the filter section, arranged approximately parallel to the plane of rotation of the fan runner and that diffuses the airflow created by the fan runner; and a sound-absorbing section which is a housing that houses a second sound-proofing plate that has no overlap with the first sound-proofing plate in the direction perpendicular to the plane of rotation of the fan runner and that collects the airflow diffused by the first sound-proofing plate. Effect of the Invention

[0012] According to the present invention, it is possible to reduce the noise generated by the fan runner and the motor. [Brief description of the drawings]

[0013] [Figure 1] This is an example of a fan filter unit that does not have a sound absorbing function. [Diagram 2] This is an example of an interference type silencer. [Diagram 3] 1 is a cross-sectional view of a fan filter unit having an interference type silencer installed therein. [Figure 4] This is an example of a resonance type silencer. [Diagram 5] 1 is a cross-sectional view of a fan filter unit having a resonance type silencer installed therein; [Figure 6] This is an example of a fan filter unit equipped with an interference type silencer and a resonance type silencer. [Figure 7] 1 is an example of a diagram illustrating the connection of a fan section, a silencer section, and a filter section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments are merely illustrative for explaining the present invention, and some details have been omitted or simplified for the sake of clarity.

[0015] The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural. The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention.

[0016] Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings. EXAMPLES

[0017] Figure 1 shows an example of a fan filter unit without a sound-absorbing function. The fan unit 10, which is equipped with a fan runner and a motor, sends air to the filter, and the filter unit 20 passes the airflow 30 generated by the fan runner into clean air.

[0018] In this embodiment, an example will be described in which an interference type silencer is installed between a fan and a filter to reduce a sound of a specific frequency.

[0019] Fig. 2 shows an example of an interference type silencer. The interference type silencer 40 is a side branch having a length of 1 / 4 of the wavelength λ of the frequency of the sound to be reduced.

[0020] 3 is a cross-sectional view of an example of a fan filter unit having an interference type silencer installed therein. In this way, a silencer section 25 is provided between the fan section 10 housing the fan and the filter section 20 housing the filter.

[0021] The muffling section 25 is provided with a sound insulating plate 61 for diffusing the air flow 30 sent from the fan runner 11, and sound insulating plates 60 and 62 for collecting the diffused air flow.

[0022] These sound-proof plates can increase the effectiveness of the interference type silencer 40 by increasing the residence time of the air.

[0023] By installing this sound insulation plate 61 directly below the fan runner 11, the air flow 30 can be expanded efficiently.

[0024] If sound insulation plates 60, 62 and sound insulation plate 61 are arranged so as not to overlap with each other, with as much vertical distance as possible, and installed at both ends of the sound insulation section so as to reduce pressure loss of air flow 30, clean air can be supplied efficiently.

[0025] If the distance between the sound insulating plates 60, 62 and the sound insulating plate 61 can be changed according to the air blowing capacity of the fan runner 11, a sound deadening section corresponding to a plurality of fan sections can be provided.

[0026] If the blowing capacity of the fan runner 11 is high, sufficient clean air can be supplied even if the distance between the sound insulation plates 60, 62 and the sound insulation plate 61 is short. However, if the blowing capacity of the fan runner 11 is low, it is better to increase the distance between the sound insulation plates 60, 62 and the sound insulation plate 61.

[0027] The interference type silencer can be installed on the upper part of the sound insulation plates 60, 62 on the side receiving the sound from the fan runner 11 to effectively silence the noise.

[0028] If the surfaces of the soundproofing plates 60, 61, and 62 are coated with fluororesin, sound reflection can be reduced and the soundproofing effect can be improved. Furthermore, if sterilization or disinfection is required in the clean room, the shielding plates can be prevented from corroding due to the effects of chemicals.

[0029] This embodiment can reduce the sound of the target frequency band without reducing the air volume as much as possible. By installing an interference type silencer 40 in the path of air and sound, it is possible to reduce sound by the interference action of waves.

[0030] 7 is an example of a diagram illustrating the connection between the fan section, the muffling section, and the filter section. The fan section 10, which has a protruding section 71 provided on the outer periphery of the upper part, and the muffling section 25, which has a protruding section 74 provided on the outer periphery of the lower part, are joined by screws 70 with an elastic body such as rubber sandwiched between them to prevent air leakage.

[0031] Similarly, sound-absorbing section 25 and filter section 20 are joined by screws between overhanging section 72 and overhanging section 73. By using such a joining method, it is possible to configure a fan filter unit that appropriately combines fan section 10, sound-absorbing section 25, and filter section 20 without air leakage. EXAMPLES

[0032] 5 is a cross-sectional view of a fan filter unit having a resonance silencer 50 installed therein. An example of reduction in a specific frequency of sound when the resonance silencer 50 is installed between the fan section 10 and the filter section 20 will be described.

[0033] Figure 4 shows an example of a resonator type silencer. The frequency of the sound to be reduced is f H The following equation (1) holds true.

[0034]

number

[0035] Here, V is the speed of sound, S is the cross-sectional area of ​​the mounting part of the resonance type silencer, V0 is the volume of the resonance type silencer, and L is the length of the mounting part of the resonance type silencer.

[0036] As shown in FIG. 5, by installing a resonance type silencer 50 on the upper part of the sound insulating plates 60, 62 on the side of the fan runner 11 that receives the sound, it is possible to reduce the sound by a resonance effect. EXAMPLES

[0037] 6 shows an example in which an interference type silencer and a resonance type silencer are installed in a fan filter unit. An example in which both an interference type silencer 40 and a resonance type silencer 50 are installed between the fan section 10 and the filter section 20 to reduce sounds of a specific frequency will be described.

[0038] By installing it in the same position as in the first and second embodiments, it is possible to reduce noise from both the interference effect and the resonance effect.

[0039] In FIG. 6, the interference type silencer 40 and the resonance type silencer 50 are disposed on each of the opposing surfaces of the sound absorbing portion, but by disposing them on the same surface, interference with other devices can be prevented. [Explanation of symbols]

[0040] 10: Fan section, 11: Fan runner, 20: Filter section, 25: Sound deadening section, 30: Air flow, 40: Interference type silencer, 50: Resonance type silencer, 60: Sound insulation plate (left), 61: Sound insulation plate (center), 62: Sound insulation plate (right), 70: Screw, 71, 72, 73, 74: Extension section

Claims

1. a fan section which is a housing housing a fan runner which is driven by a motor to generate airflow; a filter unit which is a housing including a filter for filtering foreign matter contained in the airflow generated by the fan runner; a first sound insulating plate disposed between the fan section and the filter section, and arranged substantially parallel to the rotation plane of the fan runner, for diffusing the airflow generated by the fan runner; The fan filter unit includes a first sound-insulating plate and a sound-absorbing section which is a housing that houses a second sound-insulating plate that has no overlap with the first sound-insulating plate in a direction perpendicular to the rotation plane of the fan runner and collects the airflow diffused by the first sound-insulating plate.

2. The fan filter unit according to claim 1, The fan filter unit further comprises a resonance type silencer disposed outside the housing of the muffling section.

3. The fan filter unit according to claim 2, A fan filter unit comprising an interference type silencer which is a side branch having a length of λ / 4 of the wavelength of the noise frequency to be reduced, in the resonance type silencer outside the housing of the sound absorbing section.

4. The fan filter unit according to claim 1, The fan section has a protruding portion at its lower portion, the muffler section has protruding portions at its upper and lower portions, and the filter section has a protruding portion at its upper portion, and the fan section and the muffler section, and the muffler section and the filter section are joined at the protruding portions with screws to form a fan filter unit.

5. The fan filter unit according to claim 1, A fan filter unit in which an elastic body is sandwiched between the overhanging portion of the fan section and the overhanging portion of the muffler section, and between the overhanging portion of the muffler section and the overhanging portion of the filter section.

6. The fan filter unit according to claim 1, A fan filter unit in which the surfaces of the first soundproofing plate and the second soundproofing plate are coated with fluororesin.

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