Acoustics – Sound-modifying means – Muffler – fluid conducting type
Reexamination Certificate
1999-11-18
2001-09-04
Dang, Khanh (Department: 2837)
Acoustics
Sound-modifying means
Muffler, fluid conducting type
C181S264000, C181S272000
Reexamination Certificate
active
06283246
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a silencer. More particularly, the invention relates to a silencer effective in reducing and canceling pulsation and noise produced in the intake air and in the exhaust gas of gas compressors, such as in the intake air, exhaust gas, air and coolant of internal combustion reciprocating engines as represented by gasoline engines and diesel engines.
2. Description of the Prior Art
A variety of silencers (mufflers) have heretofore been proposed. In order to cope with noise and vibration, and to reduce and cancel pulsation in the intake air and in the exhaust gas, there have been proposed those which are in principle of the attenuation type, resonance type, sound-absorbing type, or a combination thereof.
In particular, in order to cope with noise and vibration of reciprocating engines and gas compressors, the silencers of the resonance type and attenuation type have chiefly been employed, and the study has been forwarded to a considerable degree concerning the structure and theory thereof.
For instance, Japanese Unexamined Patent Publication (Kokai) No. 155521/1984 teaches a silencer chiefly for the diesel engines having an additional by-pass exhaust pipe to deviate the phase of pulsation in the exhaust gas, so that the loop of a waveform A in a main exhaust pipe and a loop of a waveform B in the by-pass exhaust pipe are brought into agreement in a plus-to-minus relationship to reduce or cancel the amplitude of pulsation. However, this prior art involves a problem in that it is difficult to evenly distribute the exhaust gas stream into the main exhaust pipe and the by-pass exhaust pipe, which has not been solved yet.
In general, it is more difficult to reduce and cancel the pulsation in the intake air and in the exhaust gas in a region of low frequencies than in a region of high frequencies. At present, there has not still been provided the last silencer which is light in weight, compact in size and is effective in reducing undulation in the medium- to low-frequency regions.
SUMMARY OF THE INVENTION
The present inventors therefore have conducted keen study concerning the structures of the silencers of the resonance type and the attenuation type, i.e., the silencers for reducing and canceling pulsation by dispersing and canceling the pulsation. Through trial and error, the present inventors have arrived at the present invention that features a simple structure based on a hollow triangular pole and a great sound-silencing effect.
An object of the present invention is to provide a silencer for medium to low frequencies having a simple structure and featuring a large sound-silencing effect as compared to the rate of flowing the gas and the pulsating decibel.
Another object of the present invention is to provide a silencer of a compact and suitable size effective in reducing and canceling the pulsation irrespective of a fixed source of generating pulsation or moving source of generating pulsation.
The present invention provides:
a silencer in which a cylindrical inlet pipe is secured penetrating through one end surface of a hollow triangular pole and having a plurality of radial ports opened in the chamber of said hollow triangular pole in one or more sectional surfaces nearly at right angles with the axis of the pipe, an outlet pipe is secured penetrating through the other end surface of the hollow triangular pole, and pulsating gases emitted into said hollow triangular pole from the radial ports of said cylindrical inlet pipe come into collision with one another nearly in phase on a plane nearly at right angles with the axial direction of said cylindrical inlet pipe;
a silencer wherein said hollow triangular pole is a hollow equilateral triangular pole;
a silencer wherein said cylindrical inlet pipe has a bottom equipped, at the central portion on the bottom surface thereof, which a conical protuberance that is sharpened toward the inlet port;
a silencer wherein said cylindrical inlet pipe has a bottom and is tapered in a manner to decrease in cross section toward the outlet port; and
a silencer wherein a cylindrical silencing chamber is further provided to surround said hollow triangular pole, and said hollow triangular pole has pairs of through holes opposed near the vertexes thereof.
REFERENCES:
patent: 3994364 (1976-11-01), Nicoll
patent: 5246473 (1993-09-01), Harris
patent: 5760348 (1998-06-01), Heuser
patent: 53-99448 (1952-01-01), None
patent: 55-20648 (1953-07-01), None
patent: 55-17906 (1953-07-01), None
patent: 59-155521 (1984-04-01), None
patent: 6-49708 (1994-07-01), None
patent: 29-92513 (1999-10-01), None
Betech Co., Ltd.
Dang Khanh
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
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