Patent Application
20060162994
Not Applicable
Not Applicable
Not Applicable
This invention relates generally to the field of pneumatics, and more specifically to a muffler for attenuating noise produced by a pneumatic device. The muffler includes a housing, a base, and a acoustic absorption insert. The housing defines an upstream and a downstream end, with the down stream end being closed. Further the housing defines a pathway that forces the air thru a maximun route thru the acoustic material. This pathway thru a directing conduit forces airflow and sound waves into the acoustic absorbation material. Finaley, the absorption insert material is disposed within the housing and includes a web of micro-fibers configured to absorb sound waves. This muffler can be utilizd with any pneumatic device to reduce the overall sound level of the device.
Typically the pneumatic industry has used mufflers made out of either sintered bronze or a housing having an insert made out of either a porous cardboard or metal screen.
The present invention concerns a muffler for attenuating noise produced by a pneumatic device. More particularly, it relates to a reduced size muffler that incorporates an acoustic absorbing insert that is more efficient, while having less back pressure, then the mufflers presently on the market.
A wide variety of devices and machines are run pneumatically. Such devices all have a port that exhausts the air used in the device. This is typically the source of most of the high decibel noise level produced by these machines. Depending on the application, one or more exhaust ports may be typically used. Because the air is pressurized and the exhaust port relatively small in diameter, the exhausted air travels at a very high velocity. As this air flows into the surrounding ambient air, it becomes turbulent. This turbulent air causes eddies that generate pressure fluctuations, resulting in a high decibel noise level.
Depending on the application, exhaust noise levels may rise to an unacceptable level resulting, in the need for hearing protection on the part of the surrounding workers. Such high noise levels can also cause noise-induced hearing loss. A point of reference, United States standards require worker to wear hearing protection if they are exposed to continuous noise levels, over an 8 hour period, in excess of 85 decibels. International law requires hearing protection for workers if the continuous noise level is over 80 decibels for an 8 hour period.
Various techniques have been employed to minimize the effects of exhaust noise produced by a pneumatic device. For example a sound barrier or enclosure can be placed around the device. In many cases this approach is not cost effective or viable as it restricts access to the equipment and may impede operation. Workers in close proximity to the device may also wear hearing protection. Unfortunately the worker may forget to wear the provided protection, or simply choose not to wear it. Additional hearing protection impedes communication, which in itself may be a work hazard. A third more practical approach would be to attached a pneumatic muffler or silencer to the exhaust port to lower the noise level below the threshold level.
Generally speaking, pneumatic equipment related mufflers attenuate noise by presenting a barrier to exhaust airflow, rerouting it usually thru a sound absorbing or dispersing media, absorbing sound waves or blocking them. For most applications, a typical muffler includes a cylindrical housing, an inlet port cap that threads or mounts to * an exhaust port. The housing defined one or more chambers or barriers thru which the exhaust air flow is directed thru. This chamber typically has a porous media in it to absorb and breakup sound waves.
This is typically a wide variety of materials, ranging form metals and cloth to composite and cardboard materials.
Regardless of the exact configuration, first a muffler must limit the exhaust to an acceptable decibel level, Ideally 80 decibel or less, second it must minimize back pressure or exhaust restriction that will effect the performance of the device. In simplest terms, a total system pressure is required to push airflow thru the muffler. This pressure is referred to as “Back Pressure” of the muffler. It is well know that noise attenuation and back pressure are inversely related. That is to say the the better a muffler is at reducing noise the higher its back pressure will be. This is caused by the fact that most muffler pack more material into the housing to enhance the noise reduction properties of the muffler. However this increase density of material increase the overall back pressure of the muffler, thereby diminishing it's usefulness as a noise reduction device.
The primary object of the invention is to provide a better method for reducing the over all decibel level of pneumatic equipment.
Another object of the invention is to provide a better noise attenuating method while at the same time having reduced back pressure.
Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.
In accordance with a preferred embodiment of the invention, there is disclosed a muffler for attenuating noise produced by a pneumatic device. The muffler includes a housing, a base and a acoustic absorption insert. The housing defines an upstream and a downstream end, with the down stream end being closed. Further the housing defines a pathway that forces the air thru a maximum pathway thru the acoustic material. This pathway thru a directing conduit forces airflow and sound waves thru the maximum amount of acoustic absorption material. Finally, the absorption insert material is disposed within the housing and includes a web of micro-fibers configured to absorb sound waves. This muffler can be utilized with any pneumatic devices to reduce the overall sound level of the device comprising: Has a reduced over all size compared to existing mufflers, and uses a distinct design to direct and maximize the absorption pathway.
The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.
FIG. A: is a perspective view of the invention in accordance with the present invention.
FIG. B: is a coss-sectional view of the muffler of FIG. A shown without the acoustic absorbing insert.
FIG. C: is a plan view of the assemblied invention.
FIG. D: is an enlarged side cross-sectional view of the air flow path through a muffler and the acoustic absorbing material.
Detailed descriptions of the preferred embodiment are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.
One preferred embodiment of a muffler 30 is shown in FIG A. The muffler 30 includes a housing 32, an acoustic barrier material 34, and a inlet 36. In general terms, the inlet conduit directs the air flow to the far end of the muffler housing 32, and directs the air flow thru the acoustic material 34, FIG. B, disposed within the housing 32. Shows a muffler for attenuating noise produced by a pneumatic device. This embodiment includes a housing, a base and an acousitc absorbation material. The housing defines an upstream and a down stream end with the down stream end being closed. Further the pathway forces the turbulant air thru a maximun amount of absorbation material.
This directing conduit forces the airflow thru a tortous pathway of small dinier fibers, And finally is disposed within a web of micro fibers configured to absorb sound waves. This muffler can be utilized in any pneumatic device to reduce overall noise level.
While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
