Muffler for pile driving apparatus

Claim 2

A muffler for attenuating exhaust noise from a pile driving apparatus, which comprises a first muffler section comprising: a housing having two ends; a first inlet port formed in a side of said housing substantially near a first end thereof; a first outlet port formed in a side of said housing substantially near a second end thereof; an elongated muffler passage in said housing, having a perforated substantially straight portion, said straight section extending substantially from said first end of said housing to said second end of said housing; an unperforated inlet end piece adapted to connect a first end of said straight section to said first inlet and an unperforated outlet end piece adapted to connect a second end of said straight section to the first outlet, said first and second end pieces being elbow pipe joints; acoustical absorbing material in said housing surrounding said perforated straight section and filling said housing; and screen means between said perforated straight section and said acoustical absorbing material, surrounding and in contact with said perforated straight section, said screen means being proportioned to permit access of acoustical waves from said exhaust gas noise to said acoustical absorbing material and to substantially prevent access of the exhaust gas and its contaminants to said acoustical absorbing material; said first inlet port being adapted for connection to a source of exhaust gas such that said exhaust gas travels through said muffler passage wherein noise associated with said exhaust gas is substantially attenuated.

Claim 3

A muffler according to claim 1 wherein said inlet end piece has an unperforated shield extension on its end thereof connected to the straight section such that the shield extension forms an unperforated section of the straight portion, said shield extension being substantially on a portion of the muffler passage farthest from said first inlet port to prevent incoming exhaust gas from penetrating the acoustical absorbing material as it flows through the elbow joint.

Claim 4

The muffler in accordance with claim 2 wherein said first inlet port is on a first side of said housing and said first outlet port is on a second side opposite said first side.

Claim 5

The muffler in accordance with claim 3 wherein said perforations are about 3/8 inch in diameter and said screen means are wrapped at least twice around said straight portion.

Claim 6

The muffler in accordance with claim 4 in which the housing, the exhaust passage and the end pieces are made of steel and said acoustical absorbing material is finely woven fiberglass substantially free of binders tightly and densely wrapped around said muffler chamber.

Claim 7

The muffler in accordance with claim 5 further comprising solid bonded fiberglass cornerpieces having a substantially triangular cross-section bonded into all four lengthwise corners of the housing, substantially parallel to said perforated straight section and drain ports in said housing to drain off collected moisture, oils and other liquids.

Claim 8

The muffler in accordance with claim 6 which further comprises: at least one additional muffler section identical to said first muffler section; means for connecting the first outlet port of one muffler section to the first inlet of another muffler section, such that said muffler sections can be placed adjacent one another with said connecting means interposed between said muffler sections to form a continuous muffler passage of substantial length.

Claim 9

A muffler according to claim 7, wherein said connecting means comprises recesses in said inlet and outlet ports and a resilient o-ring compressed within said recesses.

Claim 10

The muffler in accordance with claim 6 which further comprises: a second inlet on a third side of said housing adjacent the second side and substantially near the first end of said housing; a second outlet on a fourth side of said housing opposite said third side and substantially near the second end of said housing, wherein said inlet end piece is adapted to connect the first end of said perforated straight portion to both the first and the second inlets and said outlet end piece is adapted to connect the second end of said perforated straight portion to both the first and the second outlets.

Claim 11

The muffler in accordance with claim 9 which further comprises: an end muffler section identical to said first muffler section; means for connecting an outlet port to an inlet port; sealing means for closing and sealing the first inlet port and second outlet port in said first muffler section and the second inlet port and the first outlet port of the end muffler section, such that said muffler sections can be placed adjacent one another and connected in series providing a continuous muffler passage for attenuating noise associated with exhaust gas.

Claim 12

The muffler according to claim 10 which further comprises at least one interior muffler section between said first and end muffler sections, the first outlet port of each muffler section except said end muffler section being connected to the first inlet port of a next adjacent muffler section, the first inlet and second outlet of said first muffler section being closed and sealed by said sealing means, the second inlet and second outlet of each interior muffler section being closed and sealed by said sealing means and the second inlet and first outlet of said end muffler section being closed and sealed by said sealing means, to provide a continuous serpentine-like muffler passage of substantial length for attenuating noise from pile driver exhaust.

Claim 13

A muffler according to claim 11 wherein said connecting means comprises recesses in said inlet and outlet ports and a resilient o-ring compressed therebetween.

Claim 14

A muffler for attenuating exhaust noise from a pile driving apparatus comprising: a housing having four sides and two ends; a solid septum in the housing, dividing said housing into two acoustical isolation chambers of substantially equal volume, one of said chambers having an inlet port in one of said housing sides and another of said chambers having an outlet port in one of said sides, both said inlet and outlet ports being located substantially near one end of said housing; a U-shaped muffler passage within said housing connecting said inlet port to said outlet port and passing through said solid septum substantially near a second end of said housing opposite the first end, said U-shaped muffler passage having two perforated substantially straight portions, forming both legs of said U-shaped, two unperforated curved sections and an unperforated straight section passing through said septum; screen means surrounding said perforated straight leg portions; acoustical absorbing material filling said housing between its inner housing walls and said muffler passage; an unperforated inlet end piece connecting one end of a first perforated straight leg portion to said inlet port; an unperforated outlet end piece connecting one end of a second perforated straight leg portion to said outlet port; said screen means being interposed between said acoustical absorbing material and said straight leg portions such that exhaust gas directed into said inlet port passes through said U-shaped muffler passage such that said exhaust gas is substantially prevented from penetrating the acoustical absorbing material while acoustical waves carried by said exhaust gas penetrate said acoustical absorbing material whereby energy from said acoustical waves is absorbed, providing significant attenuation of exhaust noise.

Claim 15

A muffler for attenuating exhaust noise from a pile driving apparatus comprising: a housing having four sides and two ends; a solid septum in the housing, dividing said housing into two acoustical isolation chambers of substantially equal volume, one of said chambers having an inlet port in one of said housing sides and another of said chambers having an outlet port in one of said sides, both said inlet and outlet ports being located substantially near one end of said housing; a U-shaped muffler passage within said housing connecting said inlet port to said outlet port and passing through said solid septum substantially near a second end of said housing opposite the first end, said U-shaped muffler passage having two perforated substantially straight portions, forming both legs of said U-shaped, two unperforated curved sections and an unperforated straight section passing through said septum; screen means surrounding said perforated straight leg portions; acoustical absorbing material filling said housing between its inner housing walls and said muffler passage; an unperforated inlet end piece connecting one end of a first perforated straight leg portion to said inlet port; an unperforated outlet end piece connecting one end of a second perforated straight leg portion to said outlet port; said screen means being interposed between said acoustical absorbing material and said straight leg portions such that exhaust gas directed into said inlet port passes through said U-shaped muffler passage such that said exhaust gas is substantially prevented from penetrating the acoustical absorbing material while acoustical waves carried by said exhaust gas penetrate said acoustical absorbing material whereby energy from said acoustical waves is absorbed, providing significant attenuation of exhaust noise.

Claim 16

A muffler according to claim 13 wherein said housing, said septum and said muffler passage are made of steel, said inlet end piece and said outlet end piece are elbow joints and said acoustical absorbing material is finely woven fiberglass substantially free of binders wrapped tightly and densely around the muffler passage.

Claim 17

A muffler according to claim 14 wherein said inlet end piece has an unperforated shield extension forming an unperforated section of said straight leg section along a side thereof farthest from said inlet port.

Claim 18

A muffler according to claim 15 wherein said screen is wrapped at least twice around said perforated leg portions.

Claim 19

A muffler according to claim 16 wherein said inlet and outlet ports are on the same side of said housing and said outlet port is oriented such that quieted exhaust is expelled substantially horizontally.

Claim 20

A muffler according to claim 17 wherein the perforations are about 3/8 inch in diameter.

Claim 21

A muffler according to claim 18 wherein bonded fiberglass cornerpieces are affixed into all four lengthwise corners in both acoustical isolation chambers to prevent concentration of noise in said corners.

Claim 22

A muffler according to claim 19 which futher comprises drain ports in said housing to drain collected oil, moisture and other contaminants.