The butterfly valve comprises a body in which an inserting space is formed; and a disk inserted into the inserting space of the body, wherein fluid flow is opened or closed in response to rotation of the disk, wherein the disk further includes: a disk body formed of a metal; a first plastic layer formed of a first plastic on the disk body; a second plastic layer formed of a second plastic on the first plastic layer, wherein a melting point of the first plastic layer is different from a melting point of the second plastic layer, and the disk body is formed of a framework structure having an internal space.

A control flap (1) has a flap body (2) and a circumferential seal (3) capable of sealing upon abutting to a sealing surface (7) of an opening (8). The flap body (2) and the seal (3) are made of elastomers. The seal (3) is joined to the flap body (2) by a pressure plate (4) made of a thermoplastic. The control flap may be made by a method that includes: producing the flap body (2) from a thermoplastic by injection molding; producing the pressure plate (4) from a thermoplastic by injection molding; producing the seal (3) from an elastomer by injection molding; introducing the pressure plate (4) into the undercut (10) of the seal (3); inserting the pressure plate (4) with the seal (3) into the recess (16) of the flap body (2) and bonding the pressure plate (4) and flap body (2).

A preform can be made from two different materials that do not bond together by a bi-injection process, using the same mold. First an outer preform can be fashioned first, then an inner preform molded through a center hole in the outer preform, and the preforms connected. Inner/outer preform materials can be different, e.g., PET/polyolefin or polyamide, or the same, e.g., PET/PET. To prevent mutual bonding during molding of the second, a non-stick coating can be sprayed on a surface portion of the first preform prior to molding, the second. Manufacturing order can be either outer/inner, or inner/outer, and the non-stick coating sprayed on the inside/outside of the perform first molded.

A water valve, guide tube for a water valve, and associated method are provided. The water valve includes a housing and the guide tube is installed on the housing via laser welding. The guide tube and housing each provide axially facing mating surfaces which abut one another in a pre-bonded configuration. In a post-bonded configuration, a laser weld joint is formed at the interface between the mating surfaces. The joint forms a portion of an outer periphery of the housing.

The invention provides a process for producing a modified molded article capable of providing a diaphragm that is less likely to generate particles. The process for producing a modified molded article includes: molding modified polytetrafluoroethylene containing a tetrafluoroethylene unit and a modifying monomer unit based on a modifying monomer copolymerizable with tetrafluoroethylene to provide a molded article; and irradiating the molded article with not lower than 30 kGy but lower than 70 kGy of radiation at 270° C. to 310° C. to provide a modified molded article.

A duckbill valve includes a flexible and hollow body having a first shape upon being formed by injection molding. The body in the first shape has a first opening at a first end and a second opening at a second end. The body is configured to be inverted into a second shape. The second shape has a first opening at a first end and has a slit at a second end. The slit is defined by lips that are pressed together to form a seal.

A method for making a component includes the steps of providing a preform formed of carbon fibers. A first densification is performed forming a carbon composite. A first hardening of the carbon composite is performed. The method machines the carbon composite to form a shape. The method then performs a second densification and a second hardening. The method then final machines the carbon composite to form a final shape of the component.

A plastic valve for preventing distortion is disclosed. The plastic valve comprises a connection member made up of plastic, a case member formed on an outer surface of the connection member, and a flange member made up of plastic and formed at an end part of the connection member. A pipe is connected by being inserted into a hole of a central part of the connection member and a distortion prevention member for minimizing a force corresponding to distortion applied in a direction opposed to a direction of the connection is formed in the flange member. The connection member is made up of fluoride resin and the case member is made up of engineering plastic.

A preform can be made from two different materials that do not bond together by a bi-injection process, using the same mold. First an outer preform can be fashioned first, then an inner preform molded through a center hole in the outer preform, and the preforms connected. Inner/outer preform materials can be different, e.g., PET/polyolefin or polyamide, or the same, e.g., PET/PET. To prevent mutual bonding during molding of the second, a non-stick coating can be sprayed on a surface portion of the first preform prior to molding, the second. Manufacturing order can be either outer/inner, or inner/outer, and the non-stick coating sprayed on the inside/outside of the perform first molded.

A method for manufacturing a check valve unit as a liquid flow path member, in which the liquid flow path member includes, in a flow path direction of ink, a first flow path member constituting one side of a flow path, a second flow path member constituting another side of the flow path, and a check valve including a valve body configured to stop a backflow of the ink in the flow path and a check valve holding member configured to hold the valve body, the method includes a welding step for welding the first flow path member or the second flow path member, and the check valve holding member together, and also welding the first flow path member and the second flow path member together.