A twin-wall pipe comprises an internal pipe and an external pipe. The external pipe is corrugated, having elevations and troughs. The twin-wall pipe is further provided with a socket. In a transition portion towards the twin-wall pipe and the socket, provision is made for at least one overflow passage which interconnects the clearance between the external pipe and internal pipe in the vicinity of the transition portion and an adjacent elevation.

An extruder with a housing comprising parallel, partially inter-engaging bores and screws disposed therein is used when applying a method of feeding powdery bulk materials into such an extruder. A solid transport of powdery bulk material takes place in an inlet zone disposed downstream of a feed opening wherein said inlet zone is partially filled. The inlet zone is provided with at least one gas-permeable wall portion wherein a layer of bulk material is created on said wall portion, thereby prev...

A fluid end for a high-pressure pump including a unitary body with a plurality of horizontal passages each for receiving a reciprocating plunger at one of its ends and a pressure relief valve at the other of its ends. The body is provided with a corresponding number of vertical passages each of which intersect one of the horizontal passages and contains a suction valve at its bottom and a discharge valve at its top. A suction manifold is hingedly attached to the bottom of body to provide a flow ...

A fluid end for a high-pressure pump including a unitary body with a plurality of horizontal passages each for receiving a reciprocating plunger at one of its ends and a pressure relief valve at the other of its ends. The body is provided with a corresponding number of vertical passages each of which intersect one of the horizontal passages and contains a suction valve at its bottom and a discharge valve at its top. A suction manifold is hingedly attached to the bottom of body to provide a flow ...

A system, apparatus and method for treating water in a landscape pond so as to enhance the water clarity, where the water to be treated is delivered to a treatment pond to reduce the particulate matter and nutrient level of the water. The treatment pond includes a nutrient level reducing vegetation, facultative bacteria, substrate material for the bacteria (usually gravel) and a treatment apparatus. The treatment apparatus includes a generally vertically disposed hollow and cylindrical stack for...

An apparatus for the manufacture of compound pipes with an oval cross-section is equipped with mold halves which advance in a direction of production and of which two at a time combine as a pair on a molding path to form one mold. An injection head of at least one extruder is arranged upstream of the molding path. An external nozzle used for the creation of an external tube is substantially circular in shape and is located at a distance upstream of the molding path. An internal nozzle with a cro...

A drive unit for a twin-screw machine, of which the screw shafts, which can be driven in rotation in the same direction, have an axial spacing a, has two output shafts. The output shafts are provided with a respective crown gear which does not collide with the adjacent output shaft. The drive motor provided is in the form of a torque motor having a stator housing, a rotor, which is rotatably arranged in the stator housing, and at both ends of the rotor, outside the stator housing, a drive pinion...

A white light-emitting device using a fluorescent fiber includes a blue semiconductor light-emitting element (2) for emitting an excitation light (a), and an optical fiber (3) having one side end face and the other side end face, the excitation light (a) emitted from the blue semiconductor light-emitting element (2) being made incident to the one side end face to be guided to the other side end face. The optical fiber (3) includes a core containing therein a phosphor for emitting wavelength conv...

In a method for splicing material webs and an associated splicing device it is envisaged, for producing an improved joint, to join the material webs in the area of cut edges essentially overlap-free to form an endless material web, the cut edges being produced by cutting the material webs at least along a first cutting direction and along a second cutting direction, and the cutting directions enclosing an angle .alpha. such that 0.degree.<.alpha.<180.degree. applies.

A self-tightening retaining system for securing a closure in position closing an access port of a pump housing. The system includes a retaining cover for obstructing removal of the closure from a bore of the access port. The cover has external threads interengageable with screw threads of the bore. A locking device is configured for being secured to the cover such that the locking device rotates together with the cover. The locking device has a fastener receivable in a hole of the closure and ha...