JP2586485Y2 - Silencer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer which is used for a fluid machine such as a roots blower, and which is particularly suitable for suppressing fluid noise on a suction side.

[0002]

2. Description of the Related Art For example, a suction unit 2 of a roots blower 1
As shown in FIGS. 6 and 7,
An inflatable silencer 3 is conceivable.

[0003] The inflatable silencer 3 comprises a cylindrical outer cylinder 4,
End plates 5 and 6 with both ends of outer cylinder 4 mounted in a closed state, and end plate 6 above lower end plate 5 along the center of outer cylinder 4 are inserted through and project upward. A small-diameter punched metal inner pipe 7 mounted, an inlet pipe 8 concentric with the outer cylinder 4 and fixed to the outer surface of the lower end plate 5 and smaller in diameter than the outer cylinder 4, and a suction portion of the roots blower 1. A connection flange 9 is provided at a lower end of the inlet pipe 8 for connection to the inner pipe 2, and a filter section 10 is mounted so as to surround the outside of the upper protruding portion of the inner pipe 7.

The filter section 10 includes an outer filter receiver 10a and an inner filter receiver 10b made of a punched metal having an inner / outer dual structure, and both filter receivers 10a, 10b.
and a filter 10c mounted between b.

[0005] The filter part 10 is provided with a nut 12 and a bolt part 11 which is fixed to the upper end of the inner pipe 7 so as to protrude upward.
The holding plate 13 is screwed and fastened by the upper end plate 6.

A sound absorbing material 14 is filled in a hollow portion between the outer tube 4 and the inner tube 7, and an inflatable sound absorbing portion 15 is formed between the upper and lower end plates 5, 6.

[0007] By the operation of the roots blower 1, air is sucked from the filter portion 10 and is sucked into the roots blower 1 through the inner pipe 7 and the inlet pipe 8. Further, noise such as fluid noise generated on the roots blower 1 side at this time is silenced by the inflatable silencer 15 of the inflatable silencer 3.

For example, there is an inflatable silencer of this type having a structure disclosed in Japanese Utility Model Laid-Open Publication No. 60-47892.

[0009]

However, in the inflatable silencer 3, the length of the inflatable silencer 15 must be at least 1/4 of the wavelength of the frequency to be silenced. Therefore, there is a disadvantage that the whole silencer 3 becomes large when trying to silence a low frequency sound.

In the inflatable silencer 3, a sound of an odd multiple of the fundamental frequency determined by the length of the inflatable silencer 15 has a silencing effect, but a sound of a frequency outside the above does not have a silencing effect. Therefore, when sounds of various frequencies are included, usually, the inflatable silencer 1 having a plurality of different lengths is used.
5, a method of silencing is adopted, and this also has a disadvantage that the expansion type silencer 3 is enlarged.

In view of the above problems, an object of the present invention is to provide a more compact silencer while ensuring silencing performance for efficiently silencing a specific frequency sound.

[0012]

A technical means for achieving the above object is a contact means connected to a suction portion of a roots blower.
A connecting portion and an inflatable silencer portion disposed continuously to the connecting portion;
And a resonance type silencer continuously arranged in the inflatable silencer section.
And a filter disposed continuously with the resonance type silencer.
And an expansion type silencer section and the resonance type silencer.
The filter unit and the filter unit are linearly arranged, and
From the filter to the resonance silencer and the expansion silencer
The point is that the air suction path leading to the connection portion is formed in a straight line .

[0013]

According to the present invention, low-frequency sounds out of sounds emitted from a sound source are silenced by a resonance type silencer portion having a shorter length than an expansion type silencer. The sound of the frequency is silenced by the inflatable silencer.

At this time, the inflatable silencer section is arranged closer to the sound source, and the resonant silencer section is arranged farther away, so that the sound from the sound source enters the resonant silencer section. The sound becomes closer to a plane wave transmitted only in the axial direction, and the sound of the target specific resonance frequency can be efficiently silenced by the resonance type silencer.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a muffler 21 includes a connecting portion 22 connected to a suction portion 2 of a Roots blower 1, and a connecting portion 22. , And a filter unit 24 following the silencer 23.

The silencer 23 comprises an inflatable silencer 23a disposed closer to the connecting portion 22 and a resonant silencer 23b continuously arranged farther from the expander. 23a is a cylindrical outer cylinder 26 and an outer cylinder 26
End plates 27 each having a closed end at each end,
And a small-diameter perforated metal inner pipe 29 mounted between the end plates 27 and 28 along the center of the outer cylinder 26.
And a sound-absorbing material 30 mounted in a hollow portion between the outer tube 26 and the inner tube 29 in a filled state.

The upper and lower end plates 27 and 28 are provided with an inner pipe 2.
Openings 27a and 28a having the same diameter as the inner diameter of the nozzle 9 are formed in communication with the respective centers thereof.

The resonance type silencer section 23b is
6, and end plates 28 and 32 attached with both ends of the outer cylinder 31 closed.
And a resonance tube 33 mounted along the center of the outer cylinder 31 between both end plates 28 and 32 and formed to have the same inner diameter as the inner tube 29. The resonance tube 33 has an appropriate diameter. An appropriate number of resonance holes 33a are formed. The cavity between the outer cylinder 31 and the resonance tube 33 is a resonance chamber 34.
It has been.

An opening 32a having the same diameter as the inner diameter of the resonance tube 33 is formed at the center of the upper end plate 32 in the same manner as described above.

At the position of the filter section 24, the end plate 3
On the upper surface side, a tail pipe 36 made of punched metal and formed to have the same inner diameter as the opening 32a of the end plate 32 is attached,
The filter section 24 mounted around the outside of the tail tube 36 includes:
As described above, an outer filter receiver 24a and an inner filter receiver 24b made of a punched metal having an inner / outer dual structure,
And a filter 24c mounted between the filter receivers 24a and 24b.

The filter portion 24 has a nut 3 attached to a bolt portion 37 fixed to the upper end of the tail tube 36 so as to protrude upward.
The holding plate 39 screwed and fastened at 8 and the end plate 32 are held in a sandwiched state. Here, as shown in FIG.
The expansion type silencer section 23a, the resonance type silencer section 23b, and the
The filter section 24 has a structure arranged linearly. Ma
In addition, the tail pipe 36 of the filter part 24 and the opening 32 of the end plate 32
a, opening of the resonance tube 33 and the end plate 28 of the resonance type silencer section 23b
Mouth 28a, inner pipe 29 of expansion type silencer part 23a, end plate 27
Of the resonance type silencer from the filter section 24 by the opening 27a of
To the connecting portion 22 through the portion 23b and the inflatable silencer portion 23a.
The leading air suction path is formed in a straight line.

As described above, the connecting portion 22 is fixed to the outer surface of the lower end plate 27 concentric with the outer cylinder 26 and has a smaller diameter than the outer cylinder 26 and the inlet pipe 41 of the roots blower 1. And a connection flange portion 42 provided at the lower end of the inlet pipe 41 for connection to the inlet pipe 41.

The embodiment of the present invention is configured as described above. When the muffler 21 is connected to the roots blower 1 and the roots blower 1 is operated, air is sucked from the filter section 24, and the tail pipe 36, resonance It is sucked into the roots blower 1 through the pipe 33, the inner pipe 29, and the inlet pipe 41. Also this sky
When sucking air, remove dust and dirt around the filter.
24, dust and the like in the roots blower 1
Intrusion of dust and the like can be effectively prevented.

At this time, the noise such as fluid sound emitted from the roots blower 1 first enters the inflatable silencer section 23a, and the fundamental frequency determined by the length and the odd number multiple of the noise emitted from the roots blower 1 are included. High frequency components are mainly silenced.

Next, the sound enters the resonance type silencer section 23b designed so that the resonance frequency matches the target low frequency sound, and the low frequency component is silenced. In this case, by passing through the expansion type silencer section 23a before reaching the resonance type silencer section 23b, the sound wave becomes close to a plane wave transmitted only in the axial direction, and the sound of the designed target resonance frequency is obtained. Is efficiently silenced by the resonance type silencer section 23b.

As described above, of the sounds emitted from the sound source, low-frequency sounds are silenced by the resonance silencer 23b, which can be configured to have a short length, and high-frequency sounds are expanded. Since the muffler is configured to be silenced by the muffler section 23a, the inflatable muffler section 23a can also be configured to be relatively short, and a more compact muffler 21 can be configured here while ensuring muffler performance.

In addition, the longer the length of the inner tube, the better the noise reduction performance of the inflatable silencer.
And the resonance type silencer section 23b is continuously connected to the expansion type silencer section 23a.
Also has good noise reduction performance. Furthermore, the suction type silencer 21
Despite the fact that the filter unit 24 is dusty
Of the tail tube 36, the resonance tube 3 and the like.
3. The air suction path composed of the inner pipe 29 and the like is formed in a straight line
This allows smooth air flow during air suction
And effectively prevent the air suction performance from lowering.
There is also an advantage of demonstrating good silencing performance.

Next, a specific embodiment will be described.
The dimensions of each part of the silencer 21 in the embodiment of the present invention shown in FIG. 2 are as follows: the inner diameter R1 of the inlet pipe 41 = 60 mm, the inner diameter R2 of the outer cylinder 26 = 180 mm, and the inner diameter R3 of the tail pipe 36 = 6.
0 mm, axial length L1 of inlet pipe 41 = 80 mm, axial length L2 of inflatable silencer section 23a = 250 mm, axial length L3 of resonance type silencer section 23b = 23 mm, tail pipe 3
When the axial length L4 of No. 6 was set to 80 mm, data on the relationship between insertion loss and frequency as shown in FIG. 3 was obtained. In the figure, the solid line is a calculated value.

The dimensions of each part of the inflatable silencer 3 in the conventional example shown in FIG.
80 mm, inner diameter R12 of outer cylinder 4 = 180 mm, inner diameter R13 of inner pipe 7 = 60 mm, axial length L11 of inlet pipe 8 =
80 mm, length L12 in the axial direction of the expansion type silencer part 15 = 4
27 mm, the axial length L13 of the upper protruding portion of the inner tube 7 is 6
In the case of 0 mm, data on the relationship between insertion loss and frequency as shown in FIG. 5 was obtained. In the figure, the solid line is a calculated value.

As described above, in the silencer 21 according to the present embodiment, a large insertion loss is obtained in the designed resonance frequency range (frequency around 220 Hz in FIG. 3). In addition, it can be seen that even if the silencer 21 has a shorter overall length than the conventional inflatable silencer 3, a sound of a specific frequency can be efficiently silenced, and a muffler with equal or better silencing performance can be obtained.

The lengths of the expansion type silencer section 23a and the resonance type silencer section 23b may be appropriately set in accordance with the desired frequency of the muffling.

[0032]

As described above, according to the muffler of the present invention, the connection portion connected to the suction portion of the Roots blower and the connection portion
An inflatable silencer section continuously disposed on the continuation section;
A resonance-type silencer section continuously disposed in the silencer section;
It consists of a filter section that is arranged continuously to the muffler silencer section.
The expansion type silencer section, the resonance type silencer section, and the
The filter section is arranged linearly and the filter section
Resonant silencer section, expansion type silencer section reaches connection
The air suction path is formed in a straight line , and low-frequency sound can be silenced by the resonance type silencer part that can be configured to be shorter than the expansion type silencer, and other frequencies can be reduced. Since the sound of (1) can be silenced by the inflatable silencer section, it can be manufactured more compact while ensuring silencing performance. Also,
Since the inflatable silencer section is located closer to the sound source and the resonant silencer section is farther away, the plane wave transmitted only in the axial direction before the sound from the sound source enters the resonant silencer section And the sound of the target resonance frequency can be efficiently silenced by the resonance type silencer. In addition,
It is a suction type silencer connected to the suction part of the arts blower
Nevertheless, dust and dirt can enter the filter
Effectively prevent, and filter the resonance type silencer
Section, the air suction path to the connection through the inflatable silencer section
By forming a straight line, air suction
Smooth air flow and reduced air suction performance
There is also the advantage of effectively preventing noise and exhibiting good silencing performance.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory view of a specific embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between frequency and insertion loss in the specific embodiment.

FIG. 4 is an explanatory view of a specific example of a conventional example.

FIG. 5 is a diagram showing a relationship between frequency and insertion loss in the specific example.

FIG. 6 is an explanatory diagram showing a connection state between a roots blower and an inflatable silencer.

FIG. 7 is a sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roots blower 2 Suction part 21 Silencer 22 Connection part 23 Silencer part 23a Expansion type silencer part 23b Resonance type silencer part 24 Filter part 24a Outer filter receiver 24b Inner filter receiver 24c Filter 26 Outer cylinder 27 End plate 28 End plate 29 Inside Tube 30 sound absorbing material 31 outer tube 32 end plate 33 resonance tube 33a resonance hole 34 resonance chamber 36 tail tube 39 holding plate 41 inlet tube 42 connection flange

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-175718 (JP, A) JP-A-57-3816 (JP, U) JP-A-57-58711 (JP, U) JP-A-63 168289 (JP, U) JP 5433601 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01N 1/00-1/24 F04C 29/06

Claims (1)

(57) [Scope of request for utility model registration] 1. A connection connected to a suction portion of a roots blower.
Part and an inflatable silencer part continuously arranged at the connection part
And a resonance type silencer continuously arranged in the inflatable silencer section.
And a filter disposed continuously with the resonance type silencer.
And an expansion type silencer section and the resonance type silencer.
The filter unit and the filter unit are linearly arranged, and
From the filter to the resonance silencer and the expansion silencer
A silencer characterized in that an air suction passage leading to a connection portion is formed in a straight line .