Abstract: A high-pressure composite pipe includes a pipe-shaped inner layer made of a synthetic resin, and a reinforcing layer made of a stretched polyolefin resin sheet and wound on an external circumferential surface of the inner layer, with a winding direction of the reinforcing layer being oriented at a predetermined angle relative to an axis of the pipe, and a method for joining high-pressure composite pipes each including a pipe-shaped inner layer made of a synthetic resin, a reinforcing layer made of a stretched polyolefin resin sheet and wound on an external circumferential surface of the inner layer, and an outer layer made of a synthetic resin and laminated on the reinforcing layer.

Abstract: As the first object, the present invention intends to provide high-pressure composite pipes which show remarkable pressure resistance and optimum applicability in various uses and which can be economically manufactured in a light weight. As the second object, the present invention intends to provide a joining method which is capable of firmly joining the high-pressure composite pipes in a simple operation, firmly joining the high-pressure composite pipes by reinforcing the joint strength at the butt-fused area, and making a joint area adjustable to strain of the high-pressure composite pipes. To achieve these objects, a high-pressure composite pipe of the present invention comprises a pipe-shaped inner layer made of a synthetic resin, a reinforcing layer made of a stretched polyolefin resin sheet and wound on an external circumferential surface of the inner layer, and an outer layer made of a synthetic resin and disposed on an external circumferential surface of the reinforcing layer.

Abstract: As the first object, the present invention intends to provide high-pressure composite pipes which show remarkable pressure resistance and optimum applicability in various uses and which can be economically manufactured in a light weight. To achieve this object, a high-pressure composite pipe of the present invention comprises a pipe-shaped inner layer made of a synthetic resin, a reinforcing layer made of a stretched polyolefin resin sheet and wound on an external circumferential surface of the inner layer, and an outer layer made of a synthetic resin and disposed on an external circumferential surface of the reinforcing layer. The winding direction of the reinforcing layer is oriented at a predetermined angle relative to the axis of the pipe. Between the inner layer and the reinforcing layer and between the outer layer and the reinforcing layer, adhesion layers having affinity to these layers are interposed.

Abstract: A vacuum valve includes a housing having an operating chamber, a plunger provided in the housing; and a self-lubricating rolling diaphragm provided between the plunger and the housing. The rolling diaphragm may have a tapered form. A vacuum valve further includes a valve rod connected to the plunger and penetrating the housing to connect with a valve body. A self-lubricating shaft seal comes into contact with the valve rod to provide an airtight seal between the housing and the valve rod.

Abstract: A vacuum control valve controls the removal of sewage or other liquid removed from a tank by a vacuum discharge pipe. The control valve uses the amount of liquid in the tank, the atmospheric pressure, and the vacuum pressure of the vacuum discharge pipe to open or close a pipe communicating section which attaches the vacuum discharge pipe to a suction pipe disposed within the tank. When the pipe communicating section is opened, the liquid is removed from the tank via the suction pipe and the vacuum discharge pipe. When the tank is emptied, a damping diaphragm allows for decompression of pressure around its peripheral portion to prevent excessive suction. An opening time adjusting valve automatically self-adjusts to control the time period for a single suction activity based on the vacuum pressure inside the vacuum discharge pipe.

Abstract: A branched valve includes a main flow passage and a branch flow passage provided in a main body, a weir provided between the main and branch flow passages, and a valve disc which can contact with and come off from the weir and which selectively connects and disconnects the main and branch flow passages, wherein a branch flow entrance wall of the branch flow passage integrated with the weir has either a flat surface or a convex surface. The outer wall of the branch flow exit of the main flow passage may rise vertically from the outer wall of the main flow passage, and the side wall of the weir is located approximately on the center line of the main flow passage. The branch flow passage may be provided so that the center line thereof is located higher than the center line of the main flow passage. The valve disc may be a diaphragm.

Abstract: A method for the production of a composite pipe with at least the inner surface thereof covered with a plastic layer, comprising: forming a coiled metal sheet into a cylinder, during the conveyance of the metal sheet, by a cylindrical inner mold and at least one of a plurality of outer molds lined up in the direction of conveyance of the metal sheet, said outer mold having a housing composed of two separatable parts and being fitted around said inner mold with a fixed space; joining the side edges in the circumferential direction of said cylinder together; and extruding molten resin into a cylindrical shape over the inner surface of the cylinder from the inner mold, resulting in a composite pipe the inner surface of which is covered with a plastic layer.

Abstract: A tube joint comprising (1) a tube joint body including a tubular guide, on at least one side thereof, for receiving a tube thereon, said guide having a groove in the circumference of the end portion thereof, (2) a clamping ring including a tubular portion which has external threads and a plurality of slits extending from said external threads to the end portion thereof in the direction of the axis, said tubular portion being concentrically positioned around the guide of the tube joint body with a space therebetween which is large enough to receive the tube therein in such a manner that the end portion of the tubular portion containing the slit area corresponds to the groove in the guide, and (3) a cap nut having internal threads in one end portion thereof, which engage with the external threads of the clamping ring, and the tapered portion of the interior surface of the other end portion having an aperture therein which is greater in diameter than the outer diameter of the tube, tightening of said cap nut ot