JPS599047Y2 - Silencer for diesel engines for small fishing boats - Google Patents

Description

[Detailed description of the invention] This invention relates to a silencer for a diesel engine for a small fishing boat.

In general, silencers for this type of engine are forced to be installed in a very narrow place, inside or very close to the chimney, due to the size and structure of small fishing boats. Structurally speaking, a complex or large-scale type is not adopted, but a type that simply reduces noise by letting the exhaust gas that flows in from one side of the cylinder and expands to the other side (so-called expansion type silencer). ) has been adopted, but this method has the disadvantage that it is only effective for a specific frequency band, and therefore cannot provide the necessary and effective volume reduction for the entire range. .

In addition, recently a spiral-shaped ventilation path was installed inside the cylinder,
A system has been proposed that allows sound reduction for the entire sound range regardless of the frequency band, but this system has a continuous spiral structure in a single direction, so pressure loss is small. On the other hand, the structure itself has the disadvantage that it is extremely difficult to manufacture it below a certain size.

The object of this invention is to provide a silencer for a diesel engine for a small fishing boat, which does not have the drawbacks of the conventional ones mentioned above.

This device has an outer cylinder 2 with an inlet pipe 3 at one end that can be connected to the exhaust side of an engine, and an outlet pipe 4 at the other end that can be connected to the chimney side of a ship. An inner cylinder 5, which is shorter than the length of the outer cylinder 2 and has a porous shape, is arranged concentrically inside the cylinder 2, and the inlet pipe 3 and the outlet pipe 4, which are caused by the dimensional difference between the length of the outer cylinder 2 and the length of the inner cylinder 5, are arranged concentrically inside the cylinder 2. The side spaces 8.9 are separated by partition plates 10.11 to form expansion chambers 6 and 7, respectively, while the diameter of the outer cylinder 2 and the diameter of the inner cylinder 5 are
The annular space 13 created by the difference in diameter is filled with a sound absorbing material 14 to form the sound absorbing chamber 12, and furthermore, a guide vane with a 90-degree right twist that is split in the axial direction is fixed inwardly to the inner cylinder 5. The present invention is characterized in that at least one guide blade 16 with a left twist of 15 degrees and a left twist of 90 degrees are fixed adjacent to each other and combined.

The silencer according to this invention will be explained below with reference to the drawings.

Reference numeral 1 designates a silencer according to this invention, which, although not shown, is installed within a short distance and narrow area between the exhaust outlet end of a diesel engine for a small fishing boat and the chimney of the same boat.

Reference numeral 2 denotes the outer cylinder of the silencer 1, which is limited to a size that can be installed in the chimney of a small fishing boat.

3 is an inlet pipe, which is fixed to one end of the outer cylinder 2;
It can be connected to the exhaust side of the engine so that exhaust gas can flow in.

4 is an outlet pipe, which is fixed to the other end of the outer cylinder 2;
It can be connected to the chimney side so that exhaust gas can flow out.

5 is a punching metal (preferably 30-40% porosity)
This is a porous inner cylinder having a shape of about 100 mm or less, which is shorter than the length of the outer cylinder 2 and is arranged concentrically inside the outer cylinder 2.

Reference numerals 6 and 7 denote expansion chambers, in which equal spaces 8 and 9 of the inlet pipe 3 and the outlet pipe 4, which are caused by the dimensional difference between the length of the outer cylinder 2 and the length of the inner cylinder 5, are divided by partition plates 10 and 11. By separating them, each of them becomes stronger.

12 is an annular sound absorption chamber, which has an outer cylinder 2 diameter and an inner cylinder 5.
The shape is formed by filling a sound absorbing material 14 into the annular space 13 created by the difference in diameter.

In addition, as the sound absorbing material 14, commercially available products such as glass wool,
Appropriately modified forms will be adopted.

Reference numeral 15 indicates a guide vane with a 90 degree right twist, and 16 indicates a guide vane with a 90 degree left twist.The best guide vanes for both guide vanes 15 and 16 are, as shown in the figure, one each with equal dimensions in the axial direction. It is installed by fixing them adjacent to each other and internally fixing them to the inner cylinder 5.

In addition, in the figure, both the inlet pipe 3 and the outlet pipe 4 have a flange 1.
7.18, but the outlet pipe 4
Alternatively, the outlet pipe 4 itself may be installed directly into the chimney without providing the flange 18.

In this case, the silencer 1 itself is installed not in a horizontal position as shown in the figure, but in a vertical position.

Furthermore, it goes without saying that a desired volume reduction can be selected by appropriately changing the length, arrangement, and number of the guide vanes in accordance with the wavelength of the original exhaust sound.

Next, the effect will be explained.

The exhaust gas discharged from the engine is as shown by the solid line arrow in the figure.
It flows from the inlet pipe 3 into the expansion chamber 6, where it undergoes a change in cross-sectional area and expands, thus reducing the sound energy.

Next, the sound flows toward the inside of the inner cylinder 5, and while undergoing a significant change in the flow path corresponding to the difference in the twisting direction by the guide vanes 15 and 16, a considerable portion is reflected toward the wall surface of the inner cylinder 5 and absorbed in the sound absorption chamber 12. , the other remaining portion exits the inner cylinder 5 and enters the expansion chamber 7 again, where the sound is further reduced.

Subsequently, the sound-reduced exhaust gas is discharged through the outlet pipe 4 and discharged to the outside through the chimney.

As mentioned above, according to the silencer according to this invention, the guide vanes are divided in the axial direction and twisted to the right at 90 degrees, and the guide vanes are divided in the axial direction.
By adopting a simple structure in which guide vanes with a 0 degree left twist are combined as appropriate, the vanes themselves can be manufactured particularly easily, and as a result, it is also possible to manufacture fairly small silencers.
Therefore, the above-mentioned manufacturing disadvantages of the conventional single continuous spiral structure can be overcome, such as being able to sufficiently accommodate the space constraints of the above-mentioned applications.

Furthermore, the pressure loss of the original exhaust sound is small, and necessary and effective volume reduction can be obtained for the entire sound range, eliminating the drawbacks of the former conventional system.

Therefore, as a silencer for easel engines for small fishing boats,
Not only can it achieve a wide-area sound reduction effect, it can also contribute to improving productivity, making it ideal and highly effective in practice.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing a muffler according to this invention. 2...Outer cylinder, 3...Inlet pipe, 4...
...Outlet pipe, 5...Inner cylinder, 6,7...
・Expansion chamber, 8, 9... Space, 10.11...
...Partition plate, 12...Sound absorption chamber, 13...
...Annular space, 14...Sound absorbing material, 15.16.
...Guiding blade.

Claims (1)

[Claims for Utility Model Registration] Having an outer cylinder 2 having an inlet pipe 3 at one end that can be connected to the exhaust side of an engine, and an outlet pipe 4 at the other end that can be connected to the chimney side of a ship, An inner cylinder 5 which is shorter than the length of the outer cylinder 2 and has a porous shape is arranged concentrically inside the outer cylinder 2, and an inlet pipe 3 and an outlet pipe 4 are formed due to the dimensional difference between the length of the outer cylinder 2 and the length of the inner cylinder 5. The spaces 8 and 9 on each side are separated by partition plates 10 and 11 to form expansion chambers 6 and 7, respectively, while the outer cylinder 2 diameter and the inner cylinder 5
The annular space 13 created by the difference in diameter is filled with a sound absorbing material 14 to form the sound absorbing chamber 12, and furthermore, a guide vane with a 90-degree right twist that is split in the axial direction is fixed inwardly to the inner cylinder 5. A silencer for a diesel engine for a small fishing boat, characterized in that at least one of each of guide vanes 15 and 16 with a 90-degree left twist are fixed adjacent to each other.