Nonmetallic Patents (Class 181/246)
  • Patent number: 11473480
    Abstract: A gas turbine engine exhaust system comprises an instrumented exhaust duct including a set of exhaust temperature probes installed at the exhaust end of the duct in an air space between the engine outer case and a surrounding engine nacelle. A shield is removably installed at the end of the exhaust duct to protect the probes and associated wiring in the air space.
    Type: Grant
    Filed: February 18, 2021
    Date of Patent: October 18, 2022
    Assignee: PRATT & WHITNEY CANADA CORP.
    Inventors: Guy Lefebvre, Remy Synnott, Michael Paolucci
  • Patent number: 10655990
    Abstract: An end treatment for use with an ultrasonic gas flow meter includes an attenuation section having a pipe extending in a longitudinal direction and containing alternating sets of laterally spaced and vertically oriented first and second solid wall plates located between an inlet end and an outlet end of the pipe. One plate includes a first end connected to an inside wall of the pipe and another plate includes a second end that extends past a longitudinal centerline of the pipe to define a gap between the end of the plate and a respective opposing inside wall of the pipe. As the gas traverses the plates by flowing through the gaps, the ultrasonic waves are prevented from reflecting back to the flow meter.
    Type: Grant
    Filed: July 29, 2019
    Date of Patent: May 19, 2020
    Assignee: Big Elk Energy Systems, LLC
    Inventor: Dennis McClintock
  • Patent number: 9194513
    Abstract: A vehicle exhaust system includes a subsystem having an exterior pipe formed of a polymer. A rigid liner extends along the length of the exterior pipe and defines a passageway. A fiber insulating layer is formed between the rigid liner and the exterior pipe. The liner is formed to define at least one groove circumscribing the periphery of the passageway. The groove defines a region of increased volume of the exhaust passage along the length. The liner is further formed to define at least one void extending between the wall of the liner and the insulating layer, around the periphery of the passageway. A plurality of apertures in the liner, allow sound waves to pass from the passageway into the fiber insulating layer, and into the void.
    Type: Grant
    Filed: March 23, 2010
    Date of Patent: November 24, 2015
    Inventor: Baljit Sierra
  • Patent number: 8800713
    Abstract: A muffler for a vehicle exhaust system includes a plastic outer shell that defines an internal cavity. A metal pipe extends through the internal cavity from an inlet to an outlet. A Helmholtz chamber is formed within the plastic outer shell to attenuate a desired frequency.
    Type: Grant
    Filed: January 12, 2011
    Date of Patent: August 12, 2014
    Assignee: Faurecia Emissions Control Technologies, USA, LLC
    Inventors: Thorsten Keesser, Robin Willats, Dennis Boennen, Joseph E. Callahan
  • Patent number: 8739923
    Abstract: A muffler for a vehicle exhaust system includes a first outer shell, a second outer shell that cooperates with the first outer shell to define a muffler interior cavity, and at least one porous partition that separates the muffler interior cavity into at least first and second sub-cavities. In one example, the porous partition is integrally molded with at least one of the first and second outer shells. In one example, an exhaust tube extends through the first sub-cavity and acoustic fiber material is located within the first sub-cavity.
    Type: Grant
    Filed: January 3, 2013
    Date of Patent: June 3, 2014
    Assignee: Faurecia Emmissions Control Technologies
    Inventor: Joseph E. Callahan
  • Patent number: 8505682
    Abstract: Disclosed is a muffler assembly including: a) polymeric housing having an interior surface and at least one opening for at least one inlet and one outlet exhaust pipe; b) at least one metal inlet exhaust pipe and at least one metal outlet exhaust pipe positioned within the openings to provide housing-exhaust pipe interfaces; c) a thermal insulating material coating the interior surface of the polymeric housing and extending through the housing-exhaust pipe interfaces; wherein the thermal insulating material seals the muffler assembly at the housing-exhaust pipe interfaces; and wherein the muffler assembly has a leak rate of 105 Liters/minute or less at 4.5 psig pressure. An optional muffler assembly has body mounting adapters attached to the inlet and outlet exhaust pipes and positioned within the openings to provide housing-body mounting adapter interfaces. Also disclosed are processes for manufacturing the muffler assemblies.
    Type: Grant
    Filed: April 24, 2012
    Date of Patent: August 13, 2013
    Assignee: E I du Pont de Nemours and Company
    Inventors: Daniel P. Jones, Philippe Leboeuf, Karl Paul Maurer
  • Patent number: 8490745
    Abstract: An exhaust system component (1) of an exhaust system (2) for an internal combustion engine, especially of a motor vehicle has an inner pipe (3) made of metal, which is exposed to exhaust gas during the operation of the exhaust system (2), a housing (4) made of plastic, which encloses a working space (6), and an outer pipe (5) made of metal. The outer pipe (5) is fastened at a first end area (7) to the inner pipe (3) and is rigidly connected at a second end area (9) to the housing (4) and encloses between these end areas (7, 9) an annular space (10) formed radially between the inner pipe (3) and outer pipe (5).
    Type: Grant
    Filed: May 10, 2012
    Date of Patent: July 23, 2013
    Assignee: Eberspächer Exhaust Technology GmbH & Co. KG
    Inventors: Georg Wirth, Jan Krüger
  • Patent number: 8485314
    Abstract: An exhaust muffler of an internal combustion engine has pipe sections on the inflow side and on the outflow side, respectively, and a muffler housing that is in communication with the pipe sections. The muffler housing, which includes an outer casing and end walls, is made at least in sections of a plastic material.
    Type: Grant
    Filed: October 20, 2010
    Date of Patent: July 16, 2013
    Assignee: Faurecia Emissions Control Technologies, Germany GmbH
    Inventors: Tobias Danner, Thorsten Keesser, Thorsten Linde, Christine Huth, Marco Ranalli
  • Patent number: 8424636
    Abstract: A muffler assembly including one or more exhaust pipe(s), a polymeric housing carried by at least one of the exhaust pipe(s); a thermal insulating layer lining the housing interior surface and extending between the housing and exhaust pipe at the housing-exhaust pipe interface; wherein the thermal insulating layer includes a nonwoven fabric; wherein when the fabric is exposed to heat, the fabric increases in thickness to seal the muffler assembly at the housing-exhaust pipe interface and provides thermal insulation to the polymeric housing.
    Type: Grant
    Filed: April 24, 2012
    Date of Patent: April 23, 2013
    Assignee: E.I. du Pont de Nemours and Company
    Inventors: Daniel P. Jones, Philippe Leboeuf, Karl Paul Maurer
  • Patent number: 8418805
    Abstract: A muffler for a vehicle includes an inner casing, the inner space of the inner casing is divided by baffles to form a plurality of chambers, the inner casing having an entrance defined in one end and an exit defined in the other end, the entrance and the exit communicating with each other. An insulator surrounds the contour of the inner casing. An outer casing surrounds the contour of the insulator, the outer casing being made of synthetic resin.
    Type: Grant
    Filed: June 8, 2012
    Date of Patent: April 16, 2013
    Assignee: Hyundai Motor Company
    Inventor: Hak Son Han
  • Patent number: 8146708
    Abstract: Disclosed is a muffler (1, 21, 41) integrated with a catalytic converter bed (9, 32, 52) including a polymeric muffler body (2, 22, 42), an inlet pipe (3, 23, 43) in flow communication with engine exhaust, said inlet pipe connected to a first body mounting adapter (5, 25, 45) so as to hold the inlet pipe a heat insulating distance from said polymeric muffler body, said inlet pipe in flow communication with an inlet of said catalytic converter bed (9, 32, 52), and a perforated exhaust pipe (4, 34, 44) in flow communication with an outlet of the catalytic converter bed, said perforated exhaust pipe mounted on a second body mounting adapter (6, 26, 56) so as to hold the perforated exhaust pipe a heat insulating distance from the polymeric muffler body; said inlet pipe and said perforated exhaust pipe holding said catalytic converter bed a heat insulating distance from the polymeric muffler body, said first body mounting adapter, polymeric muffler body, and second body mounting adapter forming a sealed internal c
    Type: Grant
    Filed: January 25, 2011
    Date of Patent: April 3, 2012
    Assignee: E I du Pont de Nemours and Company
    Inventors: Karl Paul Maurer, Daniel P. Jones
  • Patent number: 8047328
    Abstract: A muffler adapted for connection with an exhaust pipe of an internal combustion engine which has an outer housing constructed of a plastic material. The housing has an inlet and at least one inwardly protruding rib extends around the interior of the housing inlet. The rib is constructed of a plastic material and forms an opening complementary in shape, but smaller in cross-sectional area, than the outer periphery of the exhaust pipe. The exhaust pipe is inserted into the inlet and the exhaust pipe and housing are vibrated relative to each other for a time period sufficient to at least partially melt the rib and cause the rib to seal around the exhaust pipe upon cooling.
    Type: Grant
    Filed: October 13, 2010
    Date of Patent: November 1, 2011
    Inventors: Mark Milewicz, Colin Murdock Drewek
  • Patent number: 7942237
    Abstract: The present invention provides composite muffler systems formed of a long fiber thermoplastic. Long fiber thermoplastic technology allows the fibers, to maintain a length sufficient to provide structural strength at lower fiber loading. The long fiber thermoplastic material for forming composite muffler systems also provides increased impact strength and creep resistance as well as chemical and thermal resistance. Mufflers molded with long fiber thermoplastics demonstrate improved dimensional stability as compared to known short fiber based moldings. One suitable muffler structure is a multi-piece muffler assembly including at least one long fiber thermoplastic shell section. In accordance with the present invention, the long fiber thermoplastic material and moldings may also be combined with over-molding of preforms of unidirectional or woven inlays, which provide local structural performance.
    Type: Grant
    Filed: December 14, 2006
    Date of Patent: May 17, 2011
    Assignee: OCV Intellectual Capital, LLC
    Inventors: Peter B. van de Flier, Norman T. Huff, Luc J L Brandt, Achim J. Reinartz
  • Patent number: 7934580
    Abstract: The present invention relates to a muffler facia assembly including a muffler with at least one thermoplastic shell formed into a facia assembly on a motor vehicle. The facia may be any suitable body part of a motor vehicle, such as a bumper, a rocker panel, an air dam, a spoiler, a sideboard or a body module. An assembly in accordance with the present invention includes structural members to provide crash management features to increase the strength and impact resistance. In accordance with the present invention, the long fiber thermoplastic material and moldings may also be combined with over-molding of preforms of unidirectional or woven inlays, which provide local structural performance. The use of such preforms is particularly suited to use in the manufacture of high temperature, structural articles such as bumper muffler combinations.
    Type: Grant
    Filed: April 12, 2006
    Date of Patent: May 3, 2011
    Assignee: OCV Intellectual Capital, LLC
    Inventors: Peter Van de Flier, Luc Peters, Norman T. Huff, Juergen P. Wiemann, Peter Derks
  • Patent number: 7810609
    Abstract: An absorption muffler includes a metallic exhaust pipe including a plurality of perforations, a polymeric housing carried by the exhaust pipe and enclosing the plurality of perforations, and including axially opposed ends. Thermal insulation is carried radially between the exhaust pipe and the polymeric housing and axially between the axially opposed ends inclusive thereof. Acoustic insulation is carried between the thermal insulation and the polymeric housing.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: October 12, 2010
    Assignees: Chrysler Group LLC, Woco Industrietechnik GmbH
    Inventors: Timothy Sikes, Udo Gaertner
  • Patent number: 7730996
    Abstract: The present invention provides composite muffler systems formed of a long fiber thermoplastic. Long fiber thermoplastic technology allows the fibers, to maintain a length sufficient to provide structural strength at lower fiber loading. The long fiber thermoplastic material for forming composite muffler systems also provides increased impact strength and creep resistance as well as chemical and thermal resistance. Mufflers molded with long fiber thermoplastics demonstrate improved dimensional stability as compared to known short fiber based moldings. One suitable muffler structure is a multi-piece muffler assembly including at least one long fiber thermoplastic shell section. In accordance with the present invention, the long fiber thermoplastic material and moldings may also be combined with over-molding of preforms of unidirectional or woven inlays, which provide local structural performance.
    Type: Grant
    Filed: April 12, 2006
    Date of Patent: June 8, 2010
    Assignee: OCV Intellectual Capital, LLC
    Inventors: Peter B. Van De Flier, Luc Peters, Juergen P. Wiemann, Peter Derks, Norman T. Huff
  • Patent number: 7543683
    Abstract: A vehicle resonator structure and attachment method is provided and includes a resonator chamber that has a first intake tube and a first exhaust or outlet tube attached thereto. At least one of the tubes includes a projection that can be molded (e.g., via flash molding after the tube itself is blow molded) onto the tube. The resonator chamber can include upper and lower tube mount structures that can be hot plate welded and sandwiched onto the projection in the tube. Thus, the tube(s) is/are positively retained in position with respect to the resonator chamber such that the tuning of the resonator does not change due to fluctuations in geometry of the tube(s) and resonator chamber structure, and such that there is little or no vibration noise and/or possible damage that might result if the tube(s) were free to move with respect to the resonator chamber.
    Type: Grant
    Filed: November 13, 2007
    Date of Patent: June 9, 2009
    Assignee: Honda Motor Co., Ltd.
    Inventors: Joel Lewis, Jacob W. Weaver
  • Patent number: 7325652
    Abstract: A bumper/muffler assembly is provided comprising a bumper; and a muffler having an outer shell. The outer shell may be formed from a non-high impact resistant material, such as a thin metal or a composite material. The muffler may comprise a separate element from the bumper, which is coupled thereto, or is formed as an integral part of the bumper.
    Type: Grant
    Filed: December 31, 2003
    Date of Patent: February 5, 2008
    Assignee: OCV Intellectual Capital, LLC
    Inventors: Norman T. Huff, Andrew W. Sanders, Christopher J. Clements, Juergen Wiemann, Ronald Tomaszewski, Larry J. Champney, Robert L. Crawley
  • Patent number: 6543577
    Abstract: A silencer (10) includes a polymeric casing (12) spaced from at least one inlet pipe and at least one outlet pipe by polymeric spacers (52). The polymeric spacers are made from a different material to that of the polymeric casing. The polymeric spacers are heat-resistant and have a higher melting point than the polymeric casing. The polymeric spacers are made of a softer material than the polymeric casing, and the polymeric spacers are capable of being deformed to accommodate irregularities in the shape of the inlet and outlet pipes.
    Type: Grant
    Filed: July 18, 2000
    Date of Patent: April 8, 2003
    Inventors: Stephanus Ferreira, Bevan John Davis
  • Patent number: 5723828
    Abstract: A hollow plastic product having a sound/noise attenuating function is provided. The product includes a duct (1) defining a flow passage and extending over a length along a longitudinal axis, a resonator (1b) having an internal chamber (1b') and a connector (1c) which establishes a fluidic communication between the flow passage of duct (1) and the internal chamber (1b') of resonator (1b). The resonator (1b) serves to absorb or attenuate sound/noise created by the fluid flowing through the flow passage. The product is manufactured from the same parison at the same time and thus has a unitary structure. An improved method for manufacturing such a hollow plastic product is also provided.
    Type: Grant
    Filed: August 23, 1995
    Date of Patent: March 3, 1998
    Assignee: Excell Corporation
    Inventor: Tatsuya Nakagawa
  • Patent number: 5542824
    Abstract: A compressor includes a motor for reciprocating a piston which sucks-in refrigerant through an inlet, and discharges compressed refrigerant through an outlet. A cylinder head forms a discharge chamber communicating with the outlet, and also forms a recess disposed opposite the inlet. Mounted in the recess is a base muffler which includes a pair of elastically flexible, tapered tubes connected by a snap-in connection to a suction muffler. Refrigerant travels through the suction muffler and the base muffler to the inlet. The base muffler insulates the refrigerant from heat radiated by the motor. A capillary tube conducts oil from an oil reservoir to the base muffler for being mixed with the refrigerant.
    Type: Grant
    Filed: April 28, 1995
    Date of Patent: August 6, 1996
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Sung-Tae Lee
  • Patent number: 5468923
    Abstract: A polymeric muffler including two halves each with baffle walls and gas flow openings integrally molded therein. The gas flow openings do not intersect with the mating edges of the baffle walls. The muffler halves are joined along the mating edges of the baffle walls and the outer walls of the two muffler halves. In a preferred embodiment, the muffler includes a filter detachably mounted on the muffler for converting exhaust gases into less toxic products. The gas flow openings are positioned to force all exhaust gas to pass through the filter.
    Type: Grant
    Filed: February 7, 1994
    Date of Patent: November 21, 1995
    Assignee: Kleyn Die Engravers, Inc.
    Inventor: Hendrik Kleyn
  • Patent number: 5424494
    Abstract: Noise is attenuated by a resonator having an inlet pipe leading to an expansion chamber and an outlet pipe leading from the expansion chamber. The two pipes are not aligned with each other at the expansion chamber. The portions of the two pipes proximate the expansion chamber contain respective venturis. The expansion chamber also functions as a Helmholtz resonator by providing the resonator with one or more apertures between the outlet pipe and the expansion chamber.
    Type: Grant
    Filed: December 10, 1992
    Date of Patent: June 13, 1995
    Assignee: Siemens Automotive Limited
    Inventors: Dennis E. Houle, Stephen E. Brackett
  • Patent number: 5321214
    Abstract: In an automobile, a silencer connected to an exhaust pipe includes a casing made of thermally resistant synthetic resin and provided at an inner surface with a thermally insulating material. The silencer is disposed between a side frame and a side body and covered with an undercover from below the silencer and is disposed between a side frame and a side body of an automatic vehicle in a space behind a rear wheel.
    Type: Grant
    Filed: December 14, 1992
    Date of Patent: June 14, 1994
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Masayuki Uegane, Akinori Sugimoto
  • Patent number: 5302783
    Abstract: In general, sound resonators or mufflers are bulky self-contained metal bodies, which are expensive to produce and to install in an engine intake or exhaust system. A relatively simple substitute, which can be tailor made to attenuate sound at various frequencies include two arcuate casing sections which are interconnected along one side edge by a hinge, so that the sections can be wrapped around an engine air intake tube, a latch on the other side edges of the sections for securing the sections together to form a sleeve around and coaxial with the tube, an inlet nozzle on the interior of each section for extending into the tube, and partitions extending between the inner and outer surfaces of each section for defining elongated, tortuous, sound attenuating passages.
    Type: Grant
    Filed: December 21, 1992
    Date of Patent: April 12, 1994
    Assignee: ABC Group
    Inventors: Changize Sadr, Douglas J. Georgas
  • Patent number: 5052513
    Abstract: In order to accomplish the aforementioned and other objects, a resin muffler, according to the invention, is formed of a heat-resistantive synthetic resin having a property of visco-elastic plasticity in a predetermined temperature range. In the visco-elastic temperature range, the motion of the molecular chain segment of the material resin comes to be relaxed to exhibit noise creative pulsating energy dissipation owing to emission as heat energy. Since the resin muffler thus absorbs noise creative energy by dissipation at around the visco-elastic temperature range and transform the energy into the heat energy which may be emitted by radiation.
    Type: Grant
    Filed: November 25, 1987
    Date of Patent: October 1, 1991
    Assignees: Showa Denko Kabushiki Kaisha, Yamato Kogyo Company, Limited
    Inventors: Hideo Yoshikawa, Katsuyoshi Takeuchi, Masami Shimada, Yoshiharu Awaji, Takashi Ikeda, Shunsaku Mitsuno
  • Patent number: 4993513
    Abstract: A muffler includes an outer box fitted over and attached to an exhaust pipe. The muffler also has a connecting member of a noncircular cross section fixed to said exhaust pipe and interposed between the exhaust pipe and the outer box.
    Type: Grant
    Filed: January 27, 1989
    Date of Patent: February 19, 1991
    Assignees: Honda Giken Kogyo Kabushiki Kaisha, Nakagawa Sangyo Co., Ltd.
    Inventors: Takeshi Inoue, Hiroshi Funabashi, Yukihiro Nakagawa
  • Patent number: 4988268
    Abstract: An air compressor comprises an air-compressing section and a pulsation-absorbing tank which are arranged isolated from each other, a nozzle, provided for one of the compressing section and the pulsation-absorbing tank, for supplying compressed air from the compressing section into the pulsation-absorbing tank, and a flexible nozzle seal provided for the other one of the compressing section and the pulsation-absorbing tank and having a hole in the center thereof. One end of the nozzle is inserted in the hole of the nozzle seal. With the nozzle inserted in the hole of the nozzle seal, the nozzle seal is applied with the pressure of the air contained in either the air compressing section or the pulsation-absorbing tank and is thus brought into light contact with the outer periphery of the nozzle.
    Type: Grant
    Filed: November 3, 1989
    Date of Patent: January 29, 1991
    Assignee: Man Design Co., Ltd.
    Inventor: Naoya Kurihara
  • Patent number: 4880078
    Abstract: An exhaust muffler for use with an internal combustion engine has at least one internal suppression chamber, at least one inlet pipe for receiving exhaust gases from the internal combustion engine, and at least one outlet pipe vented to atmosphere. The exhaust muffler comprises a plurailty of component units connected in series with each other and each having the internal suppression chamber. Each of the component units has a casing having an inner layer of a sound-absorbing material which defines the internal suppression chamber, and a connector pipe connected to and extending through the casing, the connector pipe having upstream and downstream ends projecting out of the casing, the connector pipe having at least one opening which opens into the internal suppression chamber.
    Type: Grant
    Filed: June 29, 1988
    Date of Patent: November 14, 1989
    Assignees: Honda Giken Kogyo Kabushiki Kaisha, Nakagawa Sangyo Co., Ltd.
    Inventors: Takeshi Inoue, Hiroshi Funabashi, Yukihiro Nakagawa
  • Patent number: 4844193
    Abstract: A drive shaft has a noise absorber consisting of a rubber cup-shaped element inserted in the drive shaft and a plastic insert that presses the cup-shaped element against the interior wall against the drive shaft.
    Type: Grant
    Filed: September 21, 1987
    Date of Patent: July 4, 1989
    Assignee: Eagle-Picher Industries, Inc.
    Inventors: Gary M. Veselica, Keith M. Miller, Miguel SayGan
  • Patent number: 4474260
    Abstract: A fluid operated vacuum device for manipulating a workpiece includes a rectangularly shaped metal body having a plurality of fluid passageways therein. One passageway communicates with a suction cup for creating a vacuum between the cup and the workpiece. Another fluid passageway terminates in an exhaust opening on one end of the body over which there is secured a plastic muffler for dispersing and silencing fluid exiting from the body. The muffler is substantially hollow and includes a plurality of openings in one side thereof through which exhaust fluid may escape into the ambient atmosphere. The effectiveness of the muffler is increased by a recess in the body circumscribing the exhaust opening, a perforated baffle member within the muffler, and a series of dimples in an interior wall of the muffler upon which exhaust fluid impinges.
    Type: Grant
    Filed: August 30, 1982
    Date of Patent: October 2, 1984
    Inventor: Al L. Valentine
  • Patent number: 4449610
    Abstract: A muffler on the intake tube in a hermetically sealed compressor for refrigerating apparatuses in direct communication with the intake chamber located in the compressor cylinder head. The body of the muffler, preferably made of plastic material, consists of two half-shells of identical form and structure assembled in an overlapped way and turned by 180.degree. C. with respect to each other.
    Type: Grant
    Filed: February 17, 1982
    Date of Patent: May 22, 1984
    Assignee: Necchi Societa per Azioni
    Inventor: Alfredo Bar
  • Patent number: 4408679
    Abstract: A sound attenuator for reducing noise and vibration generated by flow of air, particularly air laden with moisture, particulates and corrosive substances. The sound attenuator comprises a tubular housing and a layer of sound attenuating material, such as closed-cell polyurethane foam, removably secured in the interior of the tubular housing. A retaining ring is located at each end portion of the housing and retain the attenuating layer therebetween to avoid substantial longitudinal sliding movement of the attenuating layer by the force of air flowing therethrough. If the attenuating layer becomes abraided by particulates or absorbs an undesirable amount of moisture during use, the sound attenuating layer can be removed and replaced.
    Type: Grant
    Filed: September 28, 1981
    Date of Patent: October 11, 1983
    Assignee: Peabody Spunstrand, Inc.
    Inventor: J. Kerry Littrell
  • Patent number: 4239091
    Abstract: A muffler having a tubular cylindrical fiber-reinforced resin body with tapered extremities ending in short necks, through said body being disposed an axial aluminum tube with extremities projecting outwardly from the assembly, said tube being perforated in the section inside the body and the internal space between the body and tube being filled with sound-absorbing material. During assembly of the muffler, the internal tube and the external body are fastened by means of clamps, with the interposition of gaskets adhered with the body resin itself in order to avoid leakage between the tube and body. The sound absorbing material is also mounted on pre-fabricated channels in the body, thus eliminating the need of handling it.
    Type: Grant
    Filed: August 15, 1978
    Date of Patent: December 16, 1980
    Inventor: Paulo M. Negrao