3841results about "Rigid pipes" patented technology

The invention discloses a high-corrosion-resistance heating stainless steel composite pipe and a preparation technology thereof, and belongs to the technical field of composite pipe preparation. The stainless steel pipe serves as the innermost layer and the outermost layer, the carbon steel pipe serves as the middle part, the space between the stainless steel pipe and the carbon steel pipe is filled with the low-melting-point glass powder, the low-melting-point glass powder is melted under the high-temperature and high-pressure conditions in the machining process, and therefore welding defects such as weld cracks, air holes or gaps possibly generated in the machining process of the steel pipe are fully repaired; and the interface bonding strength and the corrosion resistance of chemical substances such as acid and alkali of the composite pipe are greatly improved, and longitudinal heat preservation and transverse heat transfer of the heating pipeline are facilitated.

The invention discloses a polyethylene composite material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The polyethylene composite material comprises the following components in parts by weight: 100 parts of high-density polyethylene, 6-20 parts of a high-density polyethylene reclaimed material, 3-16 parts of ultra-high molecular weight polyethylene, 1-6 parts of a compatilizer, 1-2 parts of an inorganic filler and 1-2 parts of a flow modifier, 2-3 parts of color master batch; wherein the viscosity average relative molecular weight of the ultra-high molecular weight polyethylene is 1,000,000-2,000,000, and the test standard is ASTM (American Society for Testing Material) D4020. According to the polyethylene composite material disclosed by the invention, part of the high-density polyethylene recycled material is doped, and the interface bonding force between the new high-density polyethylene material and the high-density polyethylene recycled material is improved through the synergistic effect of the ultra-high molecular weight polyethylene, the compatilizer and the inorganic filler; the mechanical property and the wear-resisting property of the polyethylene composite material doped with the high-density polyethylene reclaimed material are improved.

A fluid connection for a hydromotive machine or fluid-control valve having a first duct and a second duct. The first duct includes a mid-portion between a first end of the first duct and a second end of the first duct that has a non-circular cross-section. A second end of the first duct is wholly within the second end of the second duct. A first end of the second duct is wholly outside of the first duct.

The invention relates to the technical field of inorganic non-metallic materials, in particular to a quaternized cholic acid polyurethane modified polyvinyl chloride material, a preparation method and application. The quaternized cholic acid polyurethane polymer is based on a polyurethane elastomer developed by using cholic acid molecules with a rigid skeleton as a hard segment unit and flexible oligomeric ethylene glycol as a soft segment unit, hydroxyl on cholic acid polyurethane is quaternized to prepare cation modified cholic acid polyurethane, and the cation modified cholic acid polyurethane simulates amphiphilic characteristics of natural peptides. The quaternized cholic acid polyurethane is introduced into a polyvinyl chloride (PVC) matrix as an antibacterial agent, so that the growth of microorganisms such as bacteria and molds can be effectively inhibited, the antibacterial property is achieved, bacteria breeding on the inner surface of a pipeline is avoided, and the composite material is endowed with better biocompatibility and antibacterial property; meanwhile, the quaternized cholic acid polyurethane can effectively improve the strength and toughness of the PVC material; wide application prospects are realized.

The present invention provides a rubber member having excellent corrosion resistance and a semiconductor manufacturing–related device using the same. Provided is a rubber member that includes an olefin-based rubber, the rubber member being at least one member selected from the group consisting of building material members, mobility members, aerospace members, semiconductor members, and information communication members, and the rubber member coming into contact with a corrosive substance.

The invention discloses a high-strength modified high-density polyethylene double-wall corrugated pipe and a preparation method thereof, and relates to the technical field of high-density polyethylene double-wall corrugated pipes. The high-strength modified high-density polyethylene double-wall corrugated pipe is prepared from the following components: high-density polyethylene, ultra-high molecular weight polyethylene, reinforcing filler, a compatilizer, an antioxidant and a lubricant. The preparation method comprises the following steps: reinforcing filler surface modification; all the components are subjected to melt blending to prepare the modified composite material; the modified composite material is subjected to extrusion molding to form the double-wall corrugated pipe; and cooling, shaping and cutting. The UHMWPE and the reinforcing filler are introduced, and the compatilizer is combined to improve interface bonding, so that macromolecular chains of the UHMWPE are entangled to form a tough network, the reinforcing filler provides rigid support, and the high-temperature modulus and creep resistance are synergistically improved; high-temperature oxidative degradation is effectively inhibited through the antioxidant, the slow crack growth resistance time is prolonged, and the service life is prolonged.

The invention belongs to the technical field of 3PE corrosion prevention, and particularly relates to a high-temperature-resistant and cathodic disbonding-resistant 3PE corrosion-resistant pipeline and a preparation method thereof. A pipeline epoxy bottom layer, a middle adhesive layer and a polyethylene surface layer are subjected to systematic chemical synergistic modification, specifically, the epoxy bottom layer is modified with phenolic resin and amino silane, and a heat-resistant compact barrier is formed; the middle layer reacts with maleic anhydride grafted polyethylene through amino silane to construct a chemical bridge for simultaneously connecting the upper layer and the lower layer; the surface layer is grafted with high-density polyethylene through fluoroprimary amine modified glycidyl methacrylate, and a hydrophobic and oleophobic chain and a reactive functional group are introduced; according to the structure, through the synergistic effect of the high-temperature stability of the bottom layer, the two-way chemical bridging capacity of the middle layer and the inert hydrophobic characteristic of the surface layer, the long-term use temperature upper limit, the stripping resistance and the medium infiltration resistance of the pipeline are improved, and a solution is provided for long-term protection of the pipeline in the severe environment.

The invention discloses a flexible hydrogen transport PE composite pipe. The flexible hydrogen transport PE composite pipe is of a three-layer structure, raw material selection, carbon fiber pretreatment, filler pulping, coating treatment and co-extrusion forming. The method solves the problems that an existing preparation method is uneven in material mixing and poor in pipe size precision. The invention further discloses the flexible hydrogen transport PE composite pipe, the flexible hydrogen transport PE composite pipe is prepared by the preparation method of the flexible hydrogen transport PE composite pipe, and the mechanical property is also improved while the flame-retardant, antistatic and compact properties are improved.

An aircraft pipework assembly is disclosed including an aircraft structure; pipework; a fixture arrangement between the pipework and the aircraft structure; a tie rod connecting the pipework to the aircraft structure; a first tie rod bearing which connects the tie rod to the pipework; and a second tie rod bearing which connects the tie rod to the aircraft structure. The fixture arrangement includes a spherical bearing, the spherical bearing comprising a ball mounted to the pipework, and a housing coupled to the aircraft structure. The ball includes a convex spherical bearing surface; and the housing comprises a concave spherical bearing surface which mates with the convex spherical bearing surface of the ball. The fixture arrangement is configured to enable the pipework to translate relative to the ball in an axial direction aligned with a longitudinal axis of the pipework.

A fiber reinforced laminate pipe joint can include a first pipe, a second pipe, where the first pipe and the second pipe can be fiber reinforced laminate pipes, and a pipe joint insert. The pipe joint insert can be partially inserted inside the first pipe and can be partially inserted inside the second pipe. The pipe joint insert can be bonded to the first pipe and the second pipe, where the pipe joint insert can include a fiber reinforced laminate, where a bonding agent in the fiber reinforced laminate of the pipe joint insert can be distinct from a bonding agent used to bond the pipe joint insert to the first pipe.

The invention discloses a novel high-temperature-resistant and corrosion-resistant aluminum alloy plastic-lined PP-RCT composite pipe, and relates to the technical field of composite pipelines. The composite pipe is of a five-layer gradient composite structure, wherein the outer layer is an anodized aluminum alloy base body, and the inner surface is provided with laser micro-texture anchoring points; the secondary layer is a chromium-free Dacromet anti-corrosion layer, and the interface bonding force is improved through a three-dimensional network structure; the third layer is a gradient curing bonding layer which is cured by stages to eliminate thermal stress; the fourth layer is a dynamic stress compensation layer for absorbing the thermal expansion difference between the metal layer and the plastic layer; and the inner layer is a PP-RCT functional layer which has high temperature resistance and corrosion resistance. The end of the composite pipe is sealed through laser welding, an embedded intelligent monitoring system is integrated, and axial stress and temperature are monitored in real time. Compared with the prior art, the invention is suitable for pipeline systems under extreme working conditions of petrochemical engineering, ocean engineering, high-temperature fluid transportation and the like.

The invention discloses a high-density polyethylene silicon core pipe and a preparation method thereof, and relates to the technical field of silicon core pipes. The high-density polyethylene is subjected to modification treatment in different modes to obtain different modified high-density polyethylene; different modified high-density polyethylene is used as a main component, and a silicon core pipe outer-layer mixture and a silicon core pipe inner-layer mixture are prepared respectively; finally, the silicon core pipe outer layer mixture and the silicon core pipe inner layer mixture are subjected to melt co-extrusion, Si-O-C chemical bonding is generated on the inner layer and the outer layer, and the high-density polyethylene silicon core pipe is obtained. The high-density polyethylene silicon core pipe prepared by the invention is very high in interlayer bonding strength and very excellent in flame retardant property and mechanical property.

The invention relates to the field of automobile part manufacturing, and particularly discloses a barrier layer direct bonding type TPE material for an automobile air conditioner pipeline system and a preparation method and application of the barrier layer direct bonding type TPE material. The TPE material is prepared from the following raw materials: a thermoplastic elastomer TPE, PA, EVOH, polyether block amide, a glycidyl methacrylate grafted olefin copolymer elastomer, a toughening compatilizer, composite modified montmorillonite, a cold-resistant additive, an antioxidant and paraffin oil. Wherein the composite silane coupling agent, lauric acid and N, N '-carbonyldiimidazole are adopted to modify the nano-montmorillonite, so that the dispersity of nano-montmorillonite particles is improved, the formation of aggregates is effectively reduced, and the mechanical property of the material is enhanced; the polyether block amide, the glycidyl methacrylate grafted olefin copolymer elastomer and the toughening compatilizer have a synergistic effect, so that good adhesiveness of the TPE material and the barrier layer is realized.

A composite pipe includes a hollow, cylindrical liner, a flange end attachment comprising a flange and a cylindrical main body with a bore extending therethrough within which an end portion of the liner is disposed, and a thermoset outer layer comprising resin-impregnated filaments. The filaments of the thermoset outer layer are in contact with and wound about at least a portion of an external surface of the liner and at least a portion of an external surface of the cylindrical main body of the flange end attachment.

The invention discloses a high-strength composite pipe manufacturing method, and relates to the technical field of composite pipe production, and the method comprises the following steps: S1, inner ring welding: arranging and guiding inner ring reinforcing warps through a front end winding welding seat, and welding inner ring spiral wefts to the outer sides of the inner ring reinforcing warps through electric sparks, s2, mesh belt winding: wrapping a middle-layer steel wire mesh belt on the outer side of an inner-ring spiral weft through a middle-layer mesh belt winding welding seat, welding the middle-layer steel wire mesh belt on the outer side of the inner-ring spiral weft through electric sparks, and winding the middle-layer steel wire mesh belt on the outer side of the inner-ring spiral weft through a middle-layer steel wire mesh belt winding welding seat; the operation stability of production equipment is improved, the convenience of replacement and adjustment of the mesh belt storage roller is effectively improved, a mesh framework is formed by continuous online welding of warp-direction steel wires and inner and outer weft-direction steel wires, and the mesh framework and steel-plastic formed by one-time co-extrusion composite molding of polyethylene plastic penetrate through each other in a three-dimensional mode and are embedded with each other to jointly bear the working load.

The invention discloses steel, a steel pipe for hydrogen conveying and a preparation method of the steel pipe, and belongs to the technical field of pipelines. The steel comprises, by mass, not larger than 0.05% of C, 0.1%-0.3% of Si, 0.8%-1.3% of Mn, not larger than 0.02% of P, not larger than 0.01% of S, not larger than 0.03% of Al, not larger than 0.35% of Ni, not larger than 0.3% of Cr, not larger than 0.25% of Cu, not larger than 0.05% of V, not larger than 0.1% of Nb, not larger than 0.3% of Mo, not larger than 0.04% of Ti, not larger than 0.0003% of B and the balance Fe. The steel is suitable for preparing the hydrogen conveying pipeline, so that the steel is good in compatibility with the hydrogen environment and has the characteristics of excellent hydrogen induced cracking resistance, strength and toughness.

The utility model discloses a composite high-strength finish rolling steel pipe which comprises a pipe body, a bottom pipe is arranged at the bottom end of the pipe body, a top pipe is arranged at the top end of the pipe body, reinforcing ribs are arranged in the pipe body and distributed in an annular matrix mode around the center of the pipe body, and tension bands are fixedly connected to the outer surfaces of the reinforcing ribs. Inner rings of the reinforcing ribs are fixedly connected with stirrups; the bottom pipe is arranged at the bottom end of the pipe body, the top pipe is arranged at the top end of the pipe body, the reinforcing ribs welded in the bottom pipe can penetrate through the pipe body, the tension bands serve as stress points between the inner wall of the pipe body and the reinforcing ribs in the pipe body, the reinforcing ribs are fixedly supported through the tension bands, and then single-point force can be transmitted to all the reinforcing ribs and the tension bands; and the effect of dispersing transverse force is achieved, the transverse stress strength of the pipe body is improved, and the situation that the pipe body is bent and sunken due to transverse stress is reduced.

The invention relates to the technical field of pressure pipeline production, and discloses a pressure pipeline with internal lines and extrusion molding equipment, the extrusion molding equipment comprises an extruder and a shaping box, and is used for transporting the pressure pipeline extruded by the extruder and shaping the pressure pipeline in the transportation process; the cutting unit is used for cutting a new material extruded from the extruder; the butt joint unit is used for carrying the cut new material and sleeving the annular new material on the traction pipe; the first fixing plate is connected with the extruder; the adjusting assembly is used for changing the position of the new material; the second fixing plate is used for connecting the adjusting assembly; the extrusion assembly is connected with the second fixing plate, extrudes the new material located on the traction pipe and enables the new material to be separated from the traction pipe after heating work of the traction pipe is completed; the annular new materials are adsorbed and carried, the annular new materials are located on the traction pipe, the new materials are extruded, the new materials abut against the outer wall of the traction pipe, and heating of the traction pipe is completed.

The nonmetal composite pipeline comprises a main pipe, a heat preservation layer, a cushioning layer and an outer protection layer are sequentially arranged on the outer surface of the main pipe outwards, an optical fiber groove is formed in the inner surface of the heat preservation layer in the axis direction of the main pipe, an optical fiber monitoring strip is arranged in the optical fiber groove, and the optical fiber monitoring strip is formed by connecting a plurality of optical fiber sensors in series through optical fibers. The optical fiber sensor is connected with the data acquisition and processing unit through an optical fiber, the data acquisition and processing unit is wirelessly connected with the communication module, and the communication module is wirelessly connected with the remote monitoring center. The invention further discloses a preparation and monitoring method of the nonmetal composite pipeline based on optical fiber sensing. Through a multi-layer composite structure, the problems of large weight, easy corrosion and the like are solved, the optical fiber monitoring strips are integrated to sense multiple strain and pressure parameters in real time, and high-precision pipeline health monitoring is achieved in combination with remote monitoring.

The invention belongs to the technical field of nylon tube preparation, and particularly relates to an automobile nylon tube and a preparation method thereof. The composite material is prepared from the following raw materials: polyamide resin, self-repairing polysiloxane resin, graphene modified glass powder, a plasticizer, an antioxidant and a lubricant. By introducing the polysiloxane resin with self-repairing property and the glass powder, the hygroscopicity of the material can be effectively reduced, the dimensional stability of the material is enhanced, and the service life of the material is prolonged.

The invention discloses a preparation method of a vibration and noise reduction bimetal composite pipe, relates to the field of metal pipe processing, and aims to solve the problem of poor vibration and noise reduction performance of a traditional composite pipe. The preparation method comprises the steps that a composite pipe blank is provided and sequentially comprises a titanium alloy pipe and a stainless steel pipe from outside to inside, the titanium alloy pipe and the stainless steel pipe are fixed through a base, and an annular columnar filling cavity is defined by the titanium alloy pipe, the stainless steel pipe and the base; the filling cavity is filled with metal particle materials, the metal particle materials are compacted through a pressing block, and the open end of the filling cavity is sealed and welded through a cover plate; hot rolling is conducted on the composite pipe blank, and a first composite pipe blank sequentially comprising a titanium alloy layer, a porous metal layer and a stainless steel layer from outside to inside is obtained; and cutting off the pipe section of the base and the cover plate to obtain the composite pipe. And the porous metal layer formed by the metal particle material has good energy absorption performance and excellent sound insulation and heat insulation performance, so that the prepared bimetal composite pipe finally achieves the purposes of vibration and noise reduction.

The invention relates to the technical field of basalt fiber reinforced composite material pipelines and preparation methods thereof, and discloses a pipeline named as a basalt fiber reinforced composite material pipeline and a preparation method thereof and a preparation method thereof. The invention aims to overcome the defects of continuity, interface bonding and mechanical properties of the conventional basalt fiber reinforced composite material pipeline. The pipeline is composed of a lining layer, a basalt fiber winding reinforcing layer and an outer protective layer, the reinforcing layer is formed by compounding basalt fiber bundles subjected to surface treatment and a resin matrix, and the reinforcing layer is of a multi-layer structure with different winding angles. The preparation method comprises the following steps: roughening the inner lining layer, infiltrating and accurately winding the fiber bundles, performing multi-section curing and forming the outer protective layer. According to the scheme, the macroscopic mechanical property of the pipeline is remarkably improved, the interface combination of fibers and a matrix is optimized, the integrity of the fibers is kept, efficient preparation is achieved, and the pipeline has the advantages of being excellent in corrosion resistance and ultraviolet resistance, long in service life and the like.

The invention relates to a high-strength steel wire winding reinforced pipe fitting and a using method thereof, and belongs to the technical field of steel wire winding reinforced pipe fittings. When the high-strength steel wire winding reinforced pipe fitting is used in a fire-fighting pipeline system and high-pressure water flow impacts an inner rubber layer, a first sliding part moves in the axial direction of a guide rail and cooperates with a spring part to form first-stage buffering; the peak impact force is converted into elastic potential energy; when pressure fluctuates to trigger a limiting part, the arc-shaped outer edge of a swing rod makes contact with a stop lever to generate a lever effect, a second sliding part is forced to move reversely, rigid stress borne by an outer rubber layer is converted into flexible deformation of a middle buffer layer, and a rigidity abrupt change interface is effectively eliminated. And meanwhile, a multidirectional displacement compensation mechanism under the constraint of the guide rail is utilized, the reflectivity of high-frequency vibration energy is reduced, and the problem that a stress transmission path is interrupted due to the fact that a rigidity abrupt change interface is formed by a low-rigidity buffer layer and a high-rigidity outer rubber layer is fundamentally solved.

The invention discloses a marine pipe cable damping device which comprises a double-layer pipe body, a damping device and a damping device, and the double-layer pipe body is arranged outside a marine pipe cable in a sleeving mode and fixed to the marine pipe cable through a buckling device; the double-layer pipe body comprises an outer-layer pipe and an inner-layer pipe which are coaxially arranged, an interlayer space is arranged between the outer-layer pipe and the inner-layer pipe, a drainage hole communicated with the interlayer space is formed in the outer-layer pipe, an inflation buoyancy module is arranged in the interlayer space, a vibration power generation device is fixed to the outer-layer pipe, and a water pressure sensor is installed on the outer surface of the vibration power generation device; a controller is arranged on the outer surface of the outer-layer pipe, and the vibration power generation device is electrically connected with the controller; the water pressure sensor is electrically connected with the controller, and the controller is electrically connected with the inflatable buoyancy module; and a plurality of vibration reduction fins are irregularly distributed and fixed on the outer surface of the outer-layer pipe. The marine flexible pipe cable can achieve efficient vibration reduction and buoyancy adjustment, and then the stability, durability and safety of the marine flexible pipe cable in a complex dynamic environment are improved.

A composite tube assembly includes a first composite tube having a first tubular core and a first outer composite material. The first outer composite material is bonded to a first outer face of the first tubular core. The composite tube assembly further includes a second composite tube having a second tubular core and a second outer composite material. The second outer composite material is bonded to a second outer face of the second tubular core. The second composite tube is coupled to the first composite tube.

The invention discloses a polypropylene modified plastic pipe and a preparation method thereof and relates to the technical field of pipeline materials. The plastic pipe comprises an inner-layer structure and an outer-layer structure, wherein the inner layer is formed by mixing and extruding fiber powder, an interface improving agent (50-60% of a coupling agent, 30-40% of a dispersing agent and 5-10% of a defoaming agent) and polypropylene random copolymer; and the outer layer is formed by axially and uniformly distributing glass fibers or basalt fibers on the surface of the inner pipe through a yarn splitting plate, and co-extruding and coating the glass fibers or basalt fibers with fiber powder, an interface improver and polypropylene. During preparation, a double-extruder co-extrusion process is adopted, the extrusion temperature of the inner layer is 180-200 DEG C, the extrusion temperature of the outer layer is 190-210 DEG C, and the cooling rate is greater than or equal to 10 DEG C / min. Through optimization of the axial continuous fiber reinforced layer and the interface, the axial tensile strength (larger than or equal to 45 MPa) and the ring stiffness (larger than or equal to 50 kPa) of the pipeline are remarkably improved, and the problems of layering deformation and cracking of a traditional pipeline are solved.

The invention relates to the technical field of bamboo winding composite material pipelines, and discloses a bionic bamboo joint connector of a bamboo winding pressure pipeline and a processing technology of the bionic bamboo joint connector, the bionic bamboo joint connector is arranged at the connecting part of two sections of axially aligned bamboo winding pipelines, and the bionic bamboo joint connector sequentially comprises an inner lining layer and an outer lining layer from inside to outside, the embedded steel bar reinforcing layer consists of a reinforcing material and embedded steel bar glue; the film covering restraint layer is composed of fiber reinforced cloth and impregnating resin; the socket fastening layer is composed of a metal fastening piece which is connected with the two pipes in a bridging mode. A protective layer is poured, and the whole connector is wrapped with polymer modified cement mortar; the invention further provides a processing technology of the bionic bamboo joint connector. The processing technology comprises the following six steps of pretreatment, lining welding, embedded steel bar reinforcement, film covering constraint, socket fastening and pouring protection. Through the composite structure of crossed truss type embedded steel bars, polymer modified mortar pouring and socket fastening, the connector obtains high connection strength, excellent anti-drawing performance and long-term durability.

The invention belongs to the technical field of hydrogen resistance of hydrogen conveying pipelines, and particularly relates to a preparation method of a SiO2 and Al2O3 composite hydrogen resistance coating for a hydrogen conveying pipeline based on radio frequency magnetron sputtering. According to the preparation method, the SiO2 and alpha-Al2O3 composite hydrogen-resistant coating is prepared on the surface of a hydrogen conveying pipeline base material through a radio frequency magnetron sputtering method. The preparation method of the composite coating provided by the invention is simple and easy to implement and low in preparation cost, and the prepared composite hydrogen-resistant coating is uniform in particle, compact in structure, excellent in hydrogen-resistant performance and tight in interface bonding, and can be prepared by modifying various materials and utilizing radio frequency magnetron sputtering.

This invention provides a method for producing small-diameter, thick-walled near-α-type titanium alloy tubing and its application. This method, through the use of cladding and heated rolling, increases the deformation per rolling pass, reduces the number of rolling passes, and results in a finer microstructure and better mechanical properties in the heated-rolled tubing. Simultaneously, the composite material composed of the cladding layer and silica aerogel effectively prevents the alloy rod from contacting air, avoiding further surface oxidation and reducing the thickness of the oxide layer on the rod surface. Furthermore, the composite material forms a "thermal insulation layer" on the surface of the alloy rod, preventing large temperature differences between the surface and core during heated rolling, thus ensuring better microstructure uniformity and surface quality. In this invention, the cladding process expands the selection of heating furnaces and reduces equipment requirements.

The invention provides an eccentric reducing double-wall pipe adapter and a reducing double-wall eccentric connecting pipeline, and solves the problem of medium retention caused by concentric arrangement of an adapter in the prior art and the problem that the smoothness of a medium conveying channel and the sealing performance of a gas circuit are difficult to consider at the same time. The eccentric reducing double-wall pipe adapter comprises a connecting flange, one end of the connecting flange is connected with a large-aperture double-wall pipeline, and the connecting flange comprises an inner ring, an outer ring and a first gas path channel arranged between the inner ring and the outer ring; the eccentric flange comprises a large pipe connecting end, a small pipe connecting end, a first conveying channel penetrating through the large pipe connecting end and the small pipe connecting end and a second gas path channel, the large pipe connecting end is connected with the other end of the connecting flange, and the second gas path channel is communicated with the first gas path channel; the first conveying channel comprises a large-diameter opening formed in the large pipe connecting end and a small-diameter opening formed in the small pipe connecting end and eccentrically arranged with the large-diameter opening, and the bottom of the small-diameter opening is flush with the bottom of the large-diameter opening.