JPH0217293A - Muffling elbow for duct of air conditioner - Google Patents

Abstract

PURPOSE:To facilitate machinability by inserting a flexible cylindrical body formed with a complex body of a resin film outer layer, a glass wool middle layer, and a glass-fiber cloth inner layer and by winding a metal wire, into the shell of an elbow made of a metal sheet. CONSTITUTION:A flexible cylindrical body 4A is inserted into and engaged with an elbow shell 6A formed by forming and assembling a metal sheet, e.g., a galvanized steel sheet to form a muffling elbow. The flexible cylindrical body 4A is formed into a cylinder 4A by winding a complex in which an outer layer formed with a resin film 1 of, e.g., vinyl chloride film, the middle layer inside thereof formed with glass wool 2, and the innermost layer formed with a glass-fiber cloth 3 are superposed. A metal wire 5 of, e.g., a galvanized steel wire is wound spirally on the circumference in the axial direction of the cylindrical body, inside the complex. As a result, the muffling elbow can be easily formed merely by inserting the cylindrical body into the elbow shell. Also, the air duct is formed in a gentle arc causing little pressure loss.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a technology that focuses on noise prevention in air conditioning ducts in buildings.

[Prior Art] Noise generated by air passing through an air conditioning duct can be a major hindrance that affects livability.

A considerable part of the noise is generated by the operation of the blower, and in addition, noise from vortices generated in the duct due to bends in the pipe, changes in cross-sectional area, obstacles such as dampers, elbows, branch chambers, etc., and noise from the duct itself. Noise caused by vibration is added. Among these, technology has been developed to line the straight pipes and elbows of ducts with sound-absorbing material to absorb the sound source, and a method for measuring the volume reduction has already been announced (Sabin's experimental formula).

The most common technology for conventional noise-muffling elbows will be described. (
[Construction method for sound absorption and insulation of ducts] Hiroshi Ikemoto, Air Conditioning and Sanitation Engineering, Volume 52, No. 6, Pages 31 to 41, Publications of the Society of Air Conditioning and Sanitation Engineers, Figures 5A-D > Metal plates in the figure On the inner surface of the elbow outer shell 6a formed by
Washers 8 made of plated plates with copper nails 7 erected as shown in Figure A are fixed to the inner surface of the outer shell 6a at appropriate pitches by soldering, spot welding, adhesive, etc. (Figure B).

Separately, the main sound absorbing material such as rock wool or glass wool 2a is cut into uniform dimensions that are easy to install, and the glass fiber cloth 3a is cut into uniform dimensions that are easy to install.
Cover the top of the lever and attach it with glue. When installing, wrap the part to the back side to prevent the cross section from scattering (Figure C)
.

The flat plates thus fabricated are arranged on the inner surface of the outer shell 6a, a wire mesh or punching metal 9 is selected based on the known permissible wind speed value, and rivets 10 are roughly inserted into the surface of the metal mesh and punched metal 9 is selected and pasted.
The rivet is bent in the direction of the airflow to bring the sound absorbing material and punched metal into close contact with the duct outer shell (Figure D).

Such an inner lining can muffle the sounds of the elbows A (inward facing elbow) and B (right angle elbow) in Fig. 6, and is said to be effective in solving problems.

[Problem to be solved by the invention] Conventional noise-reducing elbows have a sound-reducing effect, but since the manufacturing process relies entirely on manual processing, it becomes an obstacle for large-scale duct piping, reducing overall work efficiency. cause serious deterioration.

As a result, this becomes a bottleneck for the interior design, prolonging the construction period and increasing costs.

In addition, because the hands are 1J1, individual differences between workers have a large influence, and there are noticeable differences in work speed, and variations in quality cannot be avoided, resulting in the glass wool sound absorber coming off or scattering. It is not possible to predict which products will be defective.

Further improvement is needed for the silencing effect, and for the noise caused by the vibration of the duct itself in flowing air,
It is still insufficient to buffer and calm this down by synchronizing in one direction.

In addition, from the viewpoint of air blowing efficiency, a sudden change in course by &1 is not preferable since it becomes a large resistance element and causes a large pressure loss.

In order to solve the above-mentioned problems, the present invention aims to provide a new sound deadening duct that can be mass-produced, has constant quality, and far exceeds conventional similar products in terms of sound deadening effect and pressure loss.

[Means for Solving the Problems] The noise-muffling elbow for an air conditioning duct according to the present invention includes a composite body of a resin film as an outer layer, glass wool as an intermediate layer, and glass fiber cloth as an inner layer in an elbow outer shell formed of a metal plate. The above-mentioned problem was solved by inserting and engaging a flexible cylindrical body formed with a metal wire wound helically.

In practice, it is also shown that it is more desirable to fix the punching metal that contacts the curved outer peripheral surface of the flexible cylinder inside the elbow to two sides inside the elbow outer shell in order to achieve the object of the invention.

[Operation/Example] The operation will be explained based on FIGS. 1A, B, and C and FIG. 2 showing an example of the present invention.

Figure 1 shows a partially peeled front view (A), a side sectional view (B), and a partial front sectional view (C) of an example of a mass-produced flexible cylinder.
).

In each figure, the outer layer is a resin film 1, such as a vinyl chloride film, the middle layer is glass wool 2, and the inner layer is a composite body in which glass fibers 53 are stacked together to form a cylinder 4A. The glass fiber cloth may be either a woven fabric or a non-woven fabric, and the cylindrical body is cylindrical in this example, but may be a rectangular cylindrical body as shown on the rear side.

Next, this composite body has a metal wire 5, for example a galvanized steel wire, wound therein in a spiral manner around the circumference in the axial direction of the cylinder so as to extend over its entire length. Since the cylinder 4A has such a structure, it is flexible in the axial direction, and since it has built-in metal wires as reinforcing materials, its strength is reinforced and high, and the cylinder 4A is in a flexible state as a whole.

FIG. 2 shows this cylinder 4A inserted into the elbow outer shell 6 formed by molding and assembling a metal plate, for example, a galvanized thin steel plate. Inside the outer shell 6, the inner diameter side is compressed and comes into close contact with the inner wall of the outer shell, while the outer diameter side is stretched and forms a circular arc away from the inner wall of the outer shell to form a hollow portion S. By engaging both ends of the cylinder 4A with both ends of the outer shell 6, the noise-muffling elbow is completed.

3A-8 and 4A-B respectively show a side sectional view (A) and a front sectional view (B) of different embodiments, and FIG. 3 shows a rectangular tube 4B with a rectangular cross section, The figure shows an example in which a plurality of rectangular tubes 4C each having a rectangular cross section are pushed through an elbow outer shell 6B having a rectangular cross section.

In these figures, the corners that divide the /iI path of square tubes 4B and 4C are set to have a smaller wall thickness than the corners on the outer shell side in order to increase airflow resistance. If the cross-sectional area is large, there is no need to take such consideration, and there is no problem in use even if square tubes with equal thickness on all four sides are mass-produced. On the other hand, when the air volume is large and the dynamic pressure is high, there is a risk that the flexible cylindrical body 4 will swing violently, so as shown in Fig. 3A and 4-A, a punched metal is attached to the back of the cylindrical body. It is preferable to support this by abutting 11. The effect produced by the hollow portion S is similar to that in the example No. 2 of FIG.

[Effects of the Invention] Since the present invention has the above-described configuration, it is possible to mass-produce the cylindrical body and simply insert this standard product into the standard elbow outer shell to achieve sound deadening, thereby eliminating the need for cumbersome manual work. It is completely banished, and anyone can guarantee a certain level of quality without worrying about quality.

Since the wind path changes course in a gentle arc without extreme fluctuations, there is little pressure loss and the addition of new noise elements is minimized.

Roughly speaking, since the hollow portion S is formed at the bent portion, noise and photographic images are absorbed here, further enhancing the sound deadening effect.

The unique effect of the second and third embodiments shown in Figs. 3 and 4 is that the large-diameter air duct is divided and the contact area with the sound-absorbing wall is doubled, which increases the noise reduction capacity per unit air volume. is large, and very good results can be obtained.

As described above, the present invention enjoys superior effects compared to conventional techniques not only in terms of economy and quality but also in terms of noise reduction.

[Brief explanation of the drawing]

FIGS. 1A, B, and C are a partially peeled front view (A), a side sectional view (B), a partial front sectional view (C), and FIG. A. B is a front sectional view (A) and a side sectional view (A) showing the embodiment of the present application.
B), FIGS. 3A, B and 4A, 8 are a side sectional view (A>) and a front sectional view (B) showing the second and third embodiments, respectively.
, FIGS. 5A, B, C, and D are a perspective view (A>) and a front cross-sectional partial view (B, C, D>, and FIG. 6A) showing the procedure of the prior art.
, B is a front sectional view showing a different conventional technique. 1...Resin film 3...Glass fiber cloth 5...Metal wire 11...Punching metal 2...Glass wool 4... ...Cylinder body 6...Elbow outer shell S...Hollow part

Claims (1)

[Claims] (1) In the elbow of an air conditioning duct, the outer layer is made of a resin film, the middle layer is made of glass wool, and the inner layer is made of a composite of glass fiber cloth, and a metal wire is wound in a spiral shape inside the elbow shell made of a metal plate. A noise-muffling elbow for an air conditioning duct, characterized in that a flexible cylindrical body is inserted through and engaged with the elbow. (2) The noise-muffling elbow for an air conditioning duct according to claim 1, characterized in that punching metal that contacts the curved outer peripheral surface of the flexible cylinder inside the elbow is fixed to two sides inside the elbow outer shell.