Provided is a duct that does not cause defective molding and has a highly sound absorption inner surface which can effectively suppress noise. A duct includes a tubular duct main body and a sound absorption member disposed on the inner surface of the duct main body. The duct has at least one of configurations (1) to (3): (1) the duct main body has a sandwiching part having a pair of opposite wall surfaces, and a side edge of the sound absorption member is sandwiched between the wall surfaces of the sandwiching part; (2) the sound absorption member is pasted to the inner surface of the duct main body with a resin film therebetween; and (3) the sound absorption member and duct main body have parts which are not fused to each other.

Provided is a duct that does not cause defective molding and has a highly sound absorption inner surface which can effectively suppress noise. A duct includes a tubular duct main body and a sound absorption member disposed on the inner surface of the duct main body. The duct has at least one of configurations (1) to (3): (1) the duct main body has a sandwiching part having a pair of opposite wall surfaces, and a side edge of the sound absorption member is sandwiched between the wall surfaces of the sandwiching part; (2) the sound absorption member is pasted to the inner surface of the duct main body with a resin film therebetween; and (3) the sound absorption member and duct main body have parts which are not fused to each other.

Described herein are noise attenuating ducts and vehicles using these ducts for environmental control systems. A duct comprises an exoskeleton structure and a sound-absorbing structure, disposed within and conforming to the exoskeleton structure. The exoskeleton structure provides external mechanical support to the sound-absorbing structure thereby helping to maintain the tubular shape of the sound-absorbing structure. This external support does not interfere with the airflow inside the sound-absorbing structure. Furthermore, the external positioning of the exoskeleton structure allows the integration of various support mounting features for the installation of the duct in a vehicle. In some examples, the exoskeleton structure comprises a plurality of enclosed openings to reduce the weight of the exoskeleton structure and provide additional flexibility. Furthermore, additive manufacturing of the exoskeleton structure allows achieving a monolithic structure with various features and characteristics described above.

The main subject matter of the invention is a ventilation device including at least one duct intended to channel an air flow in an air flow direction inside the duct, the ventilation device including at least one acoustic attenuation member at least partially arranged around the duct and made up of a network of resonators, each resonator having at least one cavity and one neck connecting the cavity to the duct, the resonators that make up the network of resonators being distributed at least parallel to the air flow direction. A distance separating two necks varies along a direction parallel to the air flow direction and in that a volume of the cavities varies along the direction parallel to the air flow direction.

There is provided a hydrogen supply piping for supplying hydrogen to a fuel cell, the hydrogen supply piping includes a flow path pipe member through which the hydrogen flows, and a coating member having a tube shape for covering an outer surface of the flow path pipe member. The coating member is divided into a plurality of divided pieces in pipe axis directions of the hydrogen supply piping. The divided pieces are disposed in the pipe axis directions so that an end of one of the divided pieces overlaps with an end of the adjacent divided piece. The divided pieces are wrapped tightly around an outer surface of the flow path pipe member by thermal contraction.

There is provided a hydrogen supply piping for supplying hydrogen to a fuel cell, the hydrogen supply piping includes a flow path pipe member through which the hydrogen flows, and a coating member having a tube shape for covering an outer surface of the flow path pipe member. The coating member is divided into a plurality of divided pieces in pipe axis directions of the hydrogen supply piping. The divided pieces are disposed in the pipe axis directions so that an end of one of the divided pieces overlaps with an end of the adjacent divided piece. The divided pieces are wrapped tightly around an outer surface of the flow path pipe member by thermal contraction.

Systems and methods according to one or more embodiments are provided for providing a durable and thermally insulated duct network. A duct network may be provided by coupling two or more foam ducts to each other. In one example, a system includes a plurality of foam ducts and a plurality of foam bellows configured to couple the foam ducts to each other. The foam bellows include one or more bellow folds to allow an expansion and contraction of the foam ducts. A plurality of structural fastening systems couple the duct network to a structure of a vessel. The structural fastening systems allow for an axial movement of the duct network as the foam ducts expand and contract. Additional systems and methods are also provided.

Systems and methods according to one or more embodiments are provided for providing a durable and thermally insulated duct network. A duct network may be provided by coupling two or more foam ducts to each other. In one example, a system includes a plurality of foam ducts and a plurality of foam bellows configured to couple the foam ducts to each other. The foam bellows include one or more bellow folds to allow an expansion and contraction of the foam ducts. A plurality of structural fastening systems couple the duct network to a structure of a vessel. The structural fastening systems allow for an axial movement of the duct network as the foam ducts expand and contract. Additional systems and methods are also provided.

An air conditioning pipe for carrying a gas in an aircraft includes a wall which is a sandwich component. The wall contains at least one woven fabric which forms a first ply of the wall and at least one fibrous web, made from a material containing glass, which forms a second ply of the wall. A method for producing the air conditioning pipe is also provided.

An air conditioning pipe for carrying a gas in an aircraft includes a wall which is a sandwich component. The wall contains at least one woven fabric which forms a first ply of the wall and at least one fibrous web, made from a material containing glass, which forms a second ply of the wall. A method for producing the air conditioning pipe is also provided.