A fairing, in the form of a contoured restriction, submerged on a fluid channel surface of a fluid channel through which liquid flows, re-distributes velocity fields and flow geometries upstream and in some embodiments downstream of a discontinuity, thereby preventing flow separation, reducing cavitation potential and increasing flow capacity. Such discontinuities include, but are not limited to: joints, for example elbow joints, T-joints and Y-joints; valve-trims ; entrance regions to centrifugal pumps; and entrance regions to rotary valves, steps, reductions, expansions and ledges. The fairing may be fitted into the channel or integrally fabricated with the channel.

A method of custom manufacturing a fluid pressure reduction device for use in a process control valve. The method includes creating the fluid pressure reduction device using an additive manufacturing technique, which generally includes forming a body and forming a plurality of flow paths in the body. The body has an inner wall and an outer wall spaced radially outward of the inner wall. The flow paths are formed in the body between the inner wall and the outer wall of the body. Each of the flow paths includes an inlet section formed in one of the inner and outer walls, a curved intermediate section, and an outlet section formed in the other of the inner and outer walls.

A flow restriction, a flow restriction assembly and methods for manufacturing the flow restriction and the flow restriction assembly. The flow restriction is for use in a pipe so as to restrict the flow of a fluid and includes a body extending along an axis and that has i) a central portion having an essentially constant cross section, ii) an upstream portion, wherein the cross-sectional area of the upstream portion monotonically increases in a downstream direction along the axis; and iii) a downstream portion, wherein the cross-sectional area of the downstream portion monotonically decreases in the downstream direction. The flow restriction also has a plurality of central portion projections for engaging the inner surface of the pipe, each of which projects from the surface of the central portion in a direction perpendicular to the surface of the central portion by a distance of less than 500 μm.

A paper hookah hose includes a bendable tube, a smoking mouth and a connecting tube. The bendable tube is a tubular member made of paper and having at least two layers and a spiral structure. The bendable tube has a section of bellows for bending. The bendable tube may be a full bellows or a combination of a bellows and a straight tube. The smoking mouth and the connecting tube are completely made of traditional pulp.

A device for injecting water into a combustion chamber or into an intake tract of an internal combustion engine includes a rail and at least one injection valve connected to the rail. The connection is produced by means of a rail cup, which surrounds the injection valve at the rail-side end of the injection valve. The injection valve has a feed channel open toward the rail, in which feed channel at least some portions of an insert are received in order to reduce the feed cross-section.

A device for injecting water into a combustion chamber or into an intake tract of an internal combustion engine includes a rail and at least one injection valve connected to the rail. The connection is produced by means of a rail cup, which surrounds the injection valve at the rail-side end of the injection valve. The injection valve has a feed channel open toward the rail, in which feed channel at least some portions of an insert are received in order to reduce the feed cross-section.

The invention discloses a building drainage riser, its forming mold and forming method. The riser comprises a riser body and at least one spiral blade. The spiral blade is in a spiral direction on the inner wall of the riser body, and the spiral blade is fixedly connected to the inner wall of the riser body through its bottom side; the inner side of the radial section of the spiral blade presents the first normal distribution curve and the first normal distribution The abscissa axis of the curve is located on a chord of the inner wall of the riser body, and the distance from the chord to the center of the riser body is greater than half of the inner diameter of the riser body and less than the inner diameter of the riser body. The inner wall of the building drainage riser is provided with a spiral inner reinforcement with a radial section inside the first normal distribution curve, which completely eliminates the sharp tip and the sharp joint between the top and the inner wall of the building drainage riser, reduces the pressure fluctuation in the pipe during drainage and reduces the falling water flow speed. In addition, the molding die and forming method have the advantages of simple structure and low cost.

A high-pressure fuel pipe is a pipe disposed between an injector and a high-pressure fuel pump, the high-pressure fuel pump is provided on a downstream side of a low-pressure fuel pump, an engine is a single cylinder or a two-cylinder, the high-pressure fuel pump is a plunger type that performs pressurization once or twice per rotation in synchronization with a camshaft of the engine, and a volume of the high-pressure fuel pipe is k×Q/ΔP/1000×n or less, where k is a volume modulus of fuel, Q is a maximum discharge amount of the fuel in one reciprocation of the high-pressure fuel pump, ΔP is a difference between a target fuel pressure boosted by the high-pressure fuel pump and a feed fuel pressure boosted by the low-pressure fuel pump, and n is the number of times of boosting in one rotation of the high-pressure fuel pump.

A high-pressure fuel pipe is a pipe disposed between an injector and a high-pressure fuel pump, the high-pressure fuel pump is provided on a downstream side of a low-pressure fuel pump, an engine is a single cylinder or a two-cylinder, the high-pressure fuel pump is a plunger type that performs pressurization once or twice per rotation in synchronization with a camshaft of the engine, and a volume of the high-pressure fuel pipe is k×Q/ΔP/1000×n or less, where k is a volume modulus of fuel, Q is a maximum discharge amount of the fuel in one reciprocation of the high-pressure fuel pump, ΔP is a difference between a target fuel pressure boosted by the high-pressure fuel pump and a feed fuel pressure boosted by the low-pressure fuel pump, and n is the number of times of boosting in one rotation of the high-pressure fuel pump.

A flow restrictor element, especially for restricting the air flow in an air duct system of a vehicle, comprises a ring-shaped restrictor element carrier (12) to be arranged on a flow guide duct as well as at least one restrictor element (28). The at least one restrictor element (28) is arranged within the restrictor element carrier (12), radially inwardly in relation to a central axis (M) of the flow restrictor element (10) and is detachable from the restrictor element carrier (12) for changing a restriction cross-sectional area, wherein a locking device (16) is provided on an outer circumferential area (14) of the restrictor element carrier (12) for locking the restrictor element carrier (12) on a flow guide duct.