JPS63286647A - Muffler for air conditioning - Google Patents

Abstract

PURPOSE:To permit the attenuation of sound in a low frequency area, by a method wherein the opposing two surfaces of a ventilating passage are constituted of a sound absorbing layer consisting of a perforated sheets and a sound absorbing material and the other opposing two surfaces of the same are constituted of only the lining of the sound absorbing material while the ventilating passage from the outlet and inlet port of a muffler to a resonance unit is choked with an acute angle. CONSTITUTION:The opposing two surfaces of a ventilating passage 4 are provided with a sound absorbing layer consisting of a perforated sheet 5 and a sound absorbing material 6 and an air layer 8 having partitioning sheets on the outside thereof to constitute a resonance unit. Further, the angle theta of the resonance unit, from the outlet and inlet ports of a muffler to the ventilating passage, is determined so as to be 60 deg.<=theta<=90 deg.. The other opposing two surfaces are not provided with the air layer and are provided with only the lining of the sound absorbing material 6. Metallic sheet or the like is used for the perforated sheet while inorganic or organic fibers, such as glass wool, rock wool or the like, is used for the sound absorbing material. Further, at least one piece of splitter is provided in the ventilating passage 4. According to this constitution, attenuation of sound in low frequency area as well as the reduction of weight of the title muffler may be achieved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a silencer for air conditioning.

[Conventional technology]

Stop ÷ selling bones, Rinri Mei WI, Dodori Tappoku also uses sound absorbing material lined type ducts, cell type, splitter type, zigzag type, and corrugated sound absorbing materials with partitions on the elbows and inner surfaces. There is also a silencer used in conjunction with the system, which is installed in a part of the ventilation system duct.

All of these are designed to increase the sound absorption coefficient and reduce sound, and their purpose is to reduce sound in the middle and high frequency range (500 to 80001-1z).

Expansion-type silencers with sound-absorbing material lined inside are also relatively widely used, and sound is silenced by increasing the sound absorption coefficient by increasing the area of the inner sound-absorbing material and decreasing speed and pressure due to expansion. The purpose is to reduce sound in the low frequency range.

:! There is also a type with a built-in splitter inside the expansion type muffler. The splitter makes it possible to reduce mid- and high-frequency sounds (see Figure 7).

Further, a resonance type muffler having an air layer in the outer shell as shown in FIG. 6 is capable of maximally extinguishing the energy of a specific frequency by a resonance phenomenon.

"Problems to be solved by the invention" The frequency band of the noise generated by the air conditioner blower and other noise generated inside the duct is wide, and generally ranges from 63 to 80001.
1z, but a silencer with a wide range of frequencies is required, mainly for noise reduction in the low frequency range, and since the pipes are installed in the ceiling, the space is small, so it is necessary to use a silencer that can be used as part of a compact duct. A silencer that can be used as a car has been manufactured.

However, various types of silencers that are lined with general sound-absorbing materials are not effective in low frequency ranges, and expansion-type silencers and expansion-type silencers with built-in tin litter are too bulky to be installed in limited spaces. There are restrictions. In addition, resonance type mufflers have air layers on four sides, which increases their weight, increases cost, and increases their dimensions, making it difficult to install pipes in the ceiling.
1 injury is difficult.

[Failure to solve the problem]

Therefore, as a result of intensive research in order to provide a compact muffler that can reduce noise mainly in the low frequency range, we created an air layer on only two sides and defined the angles of the muffler's entrance and exit, and lined it with sound absorbing material. A compact sound damper that enables sound reduction in the low frequency range, which was impossible with cedar alone, and surpasses the performance of conventional resonant and expansion mufflers that require a large box size, or expansion mufflers with a built-in tin litter. They discovered that it is possible to provide a container and completed the present invention.

That is, the present invention provides a silencer for air conditioning in which a sound-absorbing material is lined inside the ventilation passage, and two opposing sides of the ventilation passage are provided with a sound-absorbing layer made of a perforated plate and a sound-absorbing material, and one or more partitions on the outside thereof. A resonating section is formed from an air layer having a plate, and the other two opposing surfaces are only lined with sound absorbing material, and the air passage is narrowed at an acute angle from the entrance and exit of the muffler to the resonating section. This is a silencer for air conditioning, characterized in that the air conditioner is equipped with a tin litter and one or more tin litters are provided in the ventilation passage.

The present invention will be explained using figures.

FIG. 1 shows an embodiment of the invention according to claim (1), in which (a) is a side sectional view and (bl is a front sectional view). Two opposing sides of (
A perforated plate 5 and a sound absorbing material 6 constitute a sound absorbing layer on the upper and lower surfaces in FIG. are doing. Further, at both the entrance and exit of the muffler, the resonance portion is tapered at an angle θ from here to the ventilation passage. The angle θ is preferably an acute angle, that is, 60°≦θ<9o°.

This provides a sound reduction effect in the low frequency range.

The other two opposing surfaces that do not have resonance grooves, that is, the left and right surfaces in the figure, are not provided with an air layer and only have the sound absorbing material 6 attached thereto, which contributes to weight reduction and compactness.

Here, a metal plate or the like is used as the perforated plate, and inorganic fibers or organic fibers such as glass wool, rock wool, asbestos, etc. can be used as the sound absorbing material, and inorganic fibers are preferable.

FIG. 3 shows the volume reduction of the silencer of the present invention shown in FIG. 1. Compared to the conventional resonant silencer (Figure 6), it is superior to all frequencies in the splitter, and the low frequency range of 90nHz to 90nHz is superior. Excellent in the area.

Figure 4 shows the effect of sound reduction (1) due to the distance t (unit: fl) between the partition plates in the still air layer. In particular, around 600 gates is preferable for the low frequency range. All of these are better than the case where no partition plate is provided, and may be appropriately determined in relation to the length of the silencer and the influence of the thickness described below. The thickness of the air layer is preferably in the range of 150 to 250 mm.

Next, an embodiment of the invention according to claim (2) is shown in FIG. Although one splitter 9 is provided in the center, it is preferable to provide two splitters depending on the opening size.

This allows not only the low frequency range but also the mid to high frequency range of the silencer shown in Figure 1.
This shows a much better sound reduction effect than the sound reduction in the high frequency range (Figure 5). This splitter consists of a sound absorbing material 6 surrounded by a double-sided perforated plate 5, which reaches the sound absorbing material on the right.

〔Effect of the invention〕

Kimoto ell bi〕Thoughts and thoughts 2 deaf people are empty layer f1! k
In addition to achieving sound reduction in the low frequency range compared to conventional models by using the tapered part of the acute angle of the entrance and exit leading to the ventilation passage, a wide range of sound reduction from low to high frequencies was achieved by installing a splitter in the ventilation passage. The sound level has also been improved, and since the air layer is limited to only two opposing sides, it has been made compact and lightweight, which also contributes to cost reductions by reducing installation space constraints and weight.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, and FIG. 2 is a diagram showing another embodiment (in both cases, tal is a side sectional view, and (b) is a front sectional view). Figure 3 is a graph of the volume reduction of the silencer shown in Figure 1 and the conventional one, Figure 4 is a graph showing the relationship between the volume reduction of the space between the partition plates of the air layer, and Figure 5 is a graph of the volume reduction of the silencer of Figure 2. It is a graph showing volume reduction. Figure 6 shows a conventional resonant silencer (
(Al is a side sectional view, (1) is a front sectional view), and FIG. 7 is a side sectional view and a plan view of a conventional expansion type muffler with a built-in splitter. Engineering・・・・・・・・・Silencer 2・・・・・・・・・
・・Entrance 3 ・・Exit 4・・・・・・・・
Ventilation passage 5... Perforated plate 6...
・Sound absorbing material 7... Partition plate 8...
... Air layer 9 ... Splitter

Claims (2)

[Claims] (1) In an air conditioning silencer in which a sound-absorbing material is lined inside the ventilation passage, two opposing sides of the ventilation passage have a sound-absorbing layer made of a perforated plate and a sound-absorbing material, and one or more partition plates on the outside thereof. A resonating section is formed from an air layer having a A silencer for air conditioning that is characterized by: (2) The silencer for air conditioning according to claim (1), characterized in that one or more splitters are provided in the ventilation passage.