1049results about How to "Avoid scour" patented technology

The invention discloses a revegetation system on steep rocky slopes and an implementing method thereof, which are suitable for surface vegetalization of steep rocky uncover slopes with the gradient of 60 degrees above. A slope drainage system is arranged in the system to prevent the vegetalization layer from being flushed by rainwater and reduce water loss and soil erosion; a mix-sprayed vegetalization layer plastic-covered with iron wire corrugated meshes and consisting of continuous fiber is arranged on the slopes and has stable structure, rich nutrition and functions of water conservation and ventilation. The casting separator prevents the mix-sprayed vegetalization layer from sliding downwards; and a drop irrigation facility is distributed to make sure that the vegetalization layer is moist. After maintenance of mix-sprayed construction on the slopes, the vegetable layer with herbaceous plants and shrubs can be effectively formed, thereby reconstructing the destructed vegetables on the slopes and recovering the natural landscapes on the uncover slopes.

The invention provides a natural gas hydrate water discharge gas production exploitation device and an exploitation method of the natural gas hydrate water discharge gas production exploitation device, and belongs to the technical field of natural gas hydrate exploitation. A feeding cavity (12) communicated with a natural gas hydrate layer (29) is connected with an in-well gas-liquid separator (7), an exhaust cavity (8) of the in-well gas-liquid separator (7) is communicated with a gas production sleeve pipe (17), and a water discharge opening of the in-well gas-liquid separator (7) is communicated with a liquid storage cavity (2) arranged at the lower part. According to the exploitation method adopting the device, the natural gas hydrate layer (29) is firstly heated, the in-well gas-liquid separator (7) is utilized for separating gas-water mixture generated in the natural gas hydrate decomposition process, meanwhile, a liquid level monitoring device is utilized for regulating the water discharge speed of an electric submersible pump (4), and the decomposition speed of the natural gas hydrate is controlled. The device and the method have the advantages that the natural gas hydrate exploitation well liquid accumulation can be effectively prevented, the gas production efficiency is improved, the work is safe and reliable, the environment is protected, the service life is long, and the like.

The mixed planting material for rocky slope is one kind of composition prepared by mixing at normal temperature soil, organic matter, composite fertilizer, water preserving agent, cement, pH regulator, plant seed and water. The construction process in rocky slope includes trimming slope, setting anchor rods, hanging net, spraying, seeding, covering and maintenance. The present invention makes it possible to green rocky slope fast at relatively lower cost.

A self-contained wetlands treatment system to remove pollutants from water and treat stormwater runoff or other grey water. This is system and method wherein the water is passed through a wetland filtering and treatment system. This invention removes solids, metals (dissolved / particulate), nutrients (dissolved / particulate), oils, and bacterial contaminants from the water. The system and system housing can be fabricated, built, and assembled in a broad range of sizes and materials to accommodate and treat a broad range of influent flow rates.

The invention discloses an ecological percolating type water purification groin system, which has a trapezoidal structure. A biological strengthening purification area is formed in the middle of the system, and block stone is arranged on the two sides; a mixture of sand, broken stone and soil is arranged between the steel mesh cobble stone and the block stone; submerged plants and planting bags are arranged on the outer surface of the block stone, emergent aquatic plants are arranged on the top, and a broken stone hardcore bed is arranged at the bottom; a cobble filtering body is arranged on the broken stone hardcore bed; the surface layer of the biological strengthening purification area is a reinforcing dam top; and the two sides of the reinforcing dam top are provided with stone steps. The invention has the advantages that: relatively good water purification effect is realized; the purification body can realize batch production in plants; and the pollutants in the water flow and the pollutants adsorbed on the gravel surface are absorbed and decomposed through the joint effect of the plant root system and a microbial film. The block stone can prevent the water flow from eroding the groin foundation and enhance the stability of the side slope and the resistance against storms; and the submerged plants in the stone area can purify the water in rivers and provide a good habitat for the growth of the aquatic plants in rivers, while appearing as a landscape.

The invention discloses nano coating method and device based on ultrafast ultrahigh pressure photodynamics effect, belonging to the technical field of material surface. The invention is characterized by embedding or cold welding nanometer metal powder, nanometer nonmetal powder or compound nanometer powder which are precoated on the surface of a metal matrix in the surface layer of the metal matrix by means of laser induction mechanics effect, forming a thick nanometer particle strengthening layer or a coating layer which is called as a nano coating on the surface of the metal matrix, wherein the metal matrix is impacted and strengthened by laser. The device comprises a three-dimensional hexad working platform, a water tank, a clamp, a thermocouple, a coaxial synchronous water sender, a laser beam focusing system, a 45-degree fully-reflecting mirror, a laser beam optimizing system and a nanosecond laser. By the invention, the obtained surface nano coating has firm interface joint with the matrix and the mechanical property on the surface of the metal matrix is remarkably improved. The invention has simple technical process and lower cost, and is easy to realize automation and suitable for large-scale batch production.

The invention discloses a forest fire positioning and alarming system based on a wireless sensor network, which relates to the field of wireless transmission and fire monitoring. The forest fire positioning and alarming system consists of a terminal node and a convergence node, wherein the terminal node consists of a coordinator node, a router node and an acquisition node. The invention further discloses a forest fire monitoring, finding, positioning and alarming method based on the wireless sensor network and a terminal node arrangement method. A sensor of the terminal node is used for monitoring a forest environment and a fire extinguishing point. The system has the advantages that: the wireless sensor network is applied to forest fire prevention, an origin of fire is positioned according to the characteristic of any terminal node in the wireless sensor network, and all nodes in the entire network have monitoring and positioning functions. According to the advantages of zigbee and embedding, a fire positioning and alarming system with low cost, low power consumption and high interference resitance is established.

The invention provides an ultrawhite calendering glass kiln. The kiln is characterized in that: the kiln comprises a melting furnace, a main channel, a lateral channel, and a plurality of branch channels, which are sequentially communicated; and the main channel is a cylinder channel which has a round / quadrate / rectangular / trumpet-like shape, and each corner of each channel is provided with a transition surface. According to the invention, passage sections of the main channel are improved, and simultaneously the corners of all channels are provided with the transition surfaces, so a function of one kiln corresponds to multiple lines is realized, rapid changes of the velocity and the flow of a glass melt caused by a sudden change of a channel area while the glass melt enters another channel when going through the main channel are retarded or reduced, and long-time eddy and scour of the glass melt on the corner can be avoided, thereby a lateral temperature difference generated in a process that the glass melt flows from the outlet of the melting furnace to overflow ports of the branch channels can be reduced or avoided, and the production quality and the quality stability are improved.

A self-contained wetlands treatment system to remove pollutants from water and treat stormwater runoff or other grey water. This is system and method wherein the water is passed through a wetland filtering and treatment system. This invention removes solids, metals (dissolved / particulate), nutrients (dissolved / particulate), oils, and bacterial contaminants from the water. The system and system housing can be fabricated, built, and assembled in a broad range of sizes and materials to accommodate and treat a broad range of influent flow rates.

The invention discloses a transverse polar plate bipolar static agglomeration dedusting device and a dedusting method thereof, which solve the problem that the conventional dedusting device is complex in structure and relatively poor in dedusting effect. The invention adopts the technical scheme that the transverse polar plate bipolar static agglomeration dedusting device comprises a deduster casing as well as an air inlet pipe and an air outlet located at the two ends of the deduster casing; a plurality of cathode frameworks and a plurality of anode frameworks are vertically, alternately and uniformly arranged in the deduster casing in the direction of an airflow; a plurality of cathode plates and a plurality of cathode coronal lines are alternately and uniformly distributed on the cathode frameworks in the vertical direction, and a plurality of anode plates and a plurality of anode coronal lines are alternately and uniformly arranged on the anode frameworks; moreover, the cathode coronal lines are corresponding to the central lines of the adjacent anode plates in the direction of the airflow, and the anode coronal lines are corresponding to the central lines of the adjacent cathode plates in the direction of the airflow; the cathode frameworks are connected with the high-voltage output ends of a high-voltage DC power supply via a high-voltage cable, and the anode frameworks are connected with the grounding pole of the high-voltage DC power supply via a grounding cable. The transverse polar plate bipolar static agglomeration dedusting device is simple in structure, small in size, simple and convenient to operate, outstanding in the dust collection effect of the reverse sides of the transverse polar plates, small in reentrainment of dust, and has the effect of static agglomeration dedusting.

A pixel control device and a display apparatus utilizing said pixel control device are provided. The pixel control device is electrically connected to a sub-pixel area to provide a first voltage level, a second voltage level, and a third voltage level to the sub-pixel area, so that liquid crystals can be disposed in various angles. A scan line of the pixel control device controls a first transistor, a second transistor, and a third transistor to be switched on. The first and second data lines thereof provide a first and a second data-referenced voltage levels, respectively, to determine the first, the second, and the third voltage levels.

The invention discloses a caisson and pile combined foundation of consolidated subsoil and a construction method of the caisson and pile combined foundation. The caisson and pile combined foundation of the consolidated subsoil comprises the consolidated subsoil, a sand-gravel cushion, a caisson, bored piles, pile bottom grout, top seal concrete and scour protection. The main construction method comprises the following steps: consolidating the foundation with an underwater compaction sand pile or a deep-layer cement mixing pile; laying the sand-gravel cushion on the consolidated subsoil; sinking the caisson with a skirt, pile sinking guide holes and grouting reserved pipes on the sand-gravel cushion; after the caisson is located, constructing bored piles through the pile sinking guide holes; after construction of the bored piles, casting the top seal concrete at the bottom in the caisson; grouting the bottom of the caisson through the grouting reserved pipes at the bottom of the caisson, carrying out pile bottom grouting through grouting pipes in the pile, and at last casting the top plate of the caisson. In the construction process, the scour protection shall be performed around the caisson according to requirements. The caisson and pile combined foundation of the consolidated subsoil and the construction method of the caisson and pile combined foundation, disclosed by the invention, can effectively improve vertical and horizontal bearing capacity of the caisson, and control sedimentation and horizontal displacement of the caisson.

The invention discloses an electrolytic machining technique of a micro-groove on an inner wall surface of a small aperture and a device. The technique is that: a cathode of a forming tool of a variable cross-section structure which is provided with insulation sections and conductive sections at intervals and is made of conductive metal wires of 200 to 1000 mum is positioned in an unthreaded hole of a workpiece which is processed in advance by utilizing the electrolytic machining device of the invention, the workpiece is taken as an anode, then electrolytic solution is radially flowed along an electrode wire, the electrolytic machining is carried out in the unthreaded hole, the pressure of the electrolytic solution is maintained at 1 to 5 MPa, and the micro-groove structure is obtained at the inner wall surface of the unthreaded hole by flushing the products after the processing. The diameter size of the cathode of the forming tool which is prepared by adopting the ultra-violet light masking solidification technology and the electroforming process can be as small as a few hundred microns, and a rib cooling hole structure with the hole diameter size of about 1mm can be obtained by combining the electrolytic machining technique. The adopted technical process of the invention is easy to master and has small investment, the minimal hole diameter which can be processed is small, and the processing precision is high.

The invention discloses a biological treatment method for waste mud in petroleum and natural gas exploration drilling work, which is characterized by comprising the following steps of: a, forming a microbial treatment layer, namely inoculating special microbial strains to the waste mud in a weight ratio of 3-5: 100, mixing the strains and the waste mud uniformly, stirring the mixture and natural soil with water content of 10 to 10 percent and grain diameter of less than 0.5 centimeter uniformly according to the density condition of the waste mud in a following mode to form the microbial treatment layer, adding the natural soil in an amount which is 2.5 to 3 times that of the waste mud into the waste mud with density of 1 to 1.5kg / L, adding the natural soil in an amount which is 2 to 2.5 times that of the waste mud into the waste mud with density of 1.5 to 2.5kg / L, and controlling the water content of the microbial treatment layer to be between 25 and 30 percent; b, treating the soil; and c, treating plants. The method can solve the technical problem that effusion enters underground water to pollute a water source because the natural soil with high water content and large grain diameter is easily scoured by hard rain under the condition that pollutants in a pretreatment mixture are not yet effectively degraded in the prior art.

The invention relates to seaweed bed restoration and reconstruction techniques, in particular to a simple and convenient zostera marina L. seaweed bed ecological restoration system, which comprises: fixing zostera marina L. on stones of proper sizes by thin ropes; and performing zostera marina L. cultivation and seaweed bed ecological restoration in a proper sea area, wherein the cultivation density of the zostera marina L. is 300 to 500 plants per square meter. When the method is used, the problem that the high water power of an intertidal zone affects the cultivation and survival of seaweeds and the problem that it is difficult to transplant seaweed in the sea area in a subtidal zone are solved, and the restoration or reconstruction of the zostera marina L. seaweed beds in the intertidal zone and the subtidal zone can be performed conveniently and quickly by combining with the simple, convenient and effective zostera marina L. transplanting method provided by the invention. In addition, the materials used in the invention avoid polluting the sea areas.

This invention discloses an ultrasonic microbubble contrast agent of carrier gene, it includes microbubble, fluorocarbon gas, gene or medicine. Microbubble wall is made up by lipid bielement, fluorocarbon gas is encapsulated in it, gene or medicine entrapped in microbubble envelope. This invention also discloses its preparation method, two stearyl phosphatidylcholine, two palmitoyl phosphatidyl ethanolamine, sapn-60, glycerol, phosphate buffer solution and gene or medicine is mixed as proper proportion for mechanical oscillations. The property of carry gene or medicine microbubble is stable, particle diameter disperses equally, local tissue medicine concentration can be obviously advanced though effect of transonic breaking microbubble, and curative effect is advanced and side effect can be reduced. Flushing and dilution of blood to gene and medicine can be prevented when used in body, and also prevent gene or medicine from degrading by nuclease in cycle to ensure that lot of gene and medicine can be transported to target tissue. And it is linear increase follow gene or medicine input amount in certain range.

The invention discloses a method for simulating soil slope instability induced by groundwater. The method is characterized by comprising the following steps: a, putting a physical model on a centrifugal machine; b, raising the height of an external water tank, opening a water outlet valve and a water inlet valve, carrying out water seepage into a soil layer according to the thickness of a saturated soil layer and completing the saturation process of a soil mass; c, closing the water inlet valve, reducing the height of the external water tank, improving the centrifugal acceleration to solidifyand disperse the internal pore water pressure of the physical model; d, after the solidification is finished, opening the water inlet valve, raising the height of the external water tank to the corresponding height according to the preset water level height of an internal water tank; obtaining different infiltration capacity of the water to the slope when the water in the internal water tank seepsinto the soil layer and stays at different heights, and observing the wetting front change and the slope deformation condition of the physical model. The method disclosed by the invention has the advantages that the height of the groundwater level can be accurately adjusted in real time and washing of water current to the slope body is prevented; in the whole test process, high operability, highreliability and good test effect are realized.

The invention relates to a ZrC-TiC modified C / C-SiC composite material and a preparation method thereof, belonging to the technical field of preparation of composite materials. The composite material disclosed by the invention comprises carbon fibers, a pyrolytic carbon layer, SiC and ZrC-TiC, wherein the pyrolytic carbon layer coats the surface of the carbon fibers; SiC and ZrC-TiC coat the surface of the pyrolytic carbon layer; and ZrC-TiC is uniformly distributed in SiC. The preparation method comprises the following steps: preparing a low-density C / C composite material by adopting chemical vapor infiltration; melting Si, Zr and Ti powder, infiltrating the powder into the C / C composite material by virtue of a capillary action, and forming a ceramic phase in pores by virtue of a high-temperature in-situ reaction, thereby obtaining the ZrC-TiC modified C / C-SiC composite material. With the adoption of the process method which is low in cost, rapid and convenient, the service temperature of the C / C-SiC composite material is effectively improved, and the ultra-high temperature ablation resistance of the material is greatly enhanced.

The invention discloses an offshore wind power single-pile foundation scouring protection device. The offshore wind power single-pile foundation scouring protection device is characterized in that a turbulent flow bottom plate and lateral turbulent flow plates are fixed on a single-pile foundation; one end of the single-pile foundation is fixed in a seabed, the single-pile foundation is firmly connected with the seabed and is not easily scoured away by ocean current, and the turbulent flow bottom plate is fixed on the outer side of the single-pile foundation to form a seabed protection layer structure; multiple annular turbulent flow plates are fixed to the upper end of the turbulent flow bottom plate, and the annular turbulent flow plates can effectively reduce the water flow velocity at the seabed surface and reduce the seabed scouring effect; meanwhile, the pressure of seawater on the turbulent flow bottom plate can be utilized, and the scouring phenomenon between the single-pile foundation and the seabed is effectively prevented; the lower end of the turbulent flow bottom plate makes contact with the surface of the seabed; meanwhile, the bottom of the turbulent flow bottom plate can fix the bottom of the seabed; the plurality of lateral turbulent flow plates are evenly arrayed in the circumferential direction of the single-pile foundation, the purpose of weakening vortex formation around a pile body through the lateral turbulent flow plates is achieved, and then the seabed scouring effect is weakened; and the structure is simple, the flow speed of seawater around the pile is effectively reduced, and generation of large vortexes around the pile is reduced.

The invention discloses a side slope shallow drainage system. The bottom platform of the side slope (6) is provided with drainage ditches (4), and multiple rows and rows of drainage boreholes are densely arranged on the side slope (6). (1), the distance between the drainage boreholes (1) is 2-3m, the depth is 3-4m, and the elevation angle is 0-10°, each of the drainage boreholes (1) is provided with Drainage pipe, the slope of the slope (6) is arranged with a longitudinal micro-drainage ditch (2) and / or a transverse micro-drainage ditch (3) docked with the outlet of each of the drainage pipes, the The longitudinal miniature water collection ditch (2) and / or the horizontal miniature water collection ditches (3) communicate with the drainage ditch (4). The invention is a side slope shallow layer drainage system for quickly and efficiently discharging the groundwater infiltrated by rainfall into the shallow layer soil of the side slope.

The invention relates to a method for continuously washing coal ash under a coal bed methane exploiting well in a bride type without causing pollution, comprising the following steps: putting process oil pipe columns which are used for continuously washing the coal ash under the coal bed methane exploiting well in a bride type without causing pollution into an oil well casing; packing an upper packer and a lower packer; washing a coal ash surface at the bottom of the coal bed methane well, making injected water enter an oil sleeve annular space and jet out of a nozzle to damage the coal ash surface and causing the coal ash to return to the ground surface together with flowback water; unpacking the upper packer and the lower packer, stopping a pump, lifting the process oil pipe columns and deblocking all the oil pipe columns. The invention has the advantages that the coal layer is packaged and the channels of the injected water and the flowback water are changed to form a sealed hydraulic circulating space in oil pipes, the sealed hydraulic circulating space can be matched with the oil pipe columns to form a set of working pipe columns which are convenient to butt, do not need to be demounted repeatedly and are capable of continuously washing the coal ash under the coal bed methane well, and the washing and the pollution of the injected water or the flowback water to the coal layer are effectively avoided.

A zoology recovering device for the city water bank belongs to the water zoology engineering field. The invention is to set the marsh zoology decontamination water purification system, the water-air-wind exchanging system, the land-water biological habit system and the zoology bank protecting system in the city water bank. The concrete flooding bank is set by 8-25degree with the water flow direction; The bank head is connected with the concrete through the clapboard; the bank trail is connected with the slag biological water leaking wall; the field formed by the bank, concrete flooding bank and the concrete clapboard is divided into the sunken plant field and the floating plant field by the concrete clapboard. The biological reef hill is set on the center of the sunken plant. The invention can not only recover and clear the water zoology but prevent the storm to erode the bank compared to the chemical, physical and zoological method at present.

The invention relates to an anti-air-erosion dewatering regulating valve comprising a valve body, a valve seat, valve clacks and a valve rod. The valve seat is fixed in a valve cavity encircled by the valve body, the sealing surfaces of the valve clacks and the sealing surface of the valve seat form a main sealing pair, the valve rod drives the valve clacks straightly up and down, a orifice sleeve is fixedly arranged in a valve cavity at a medium inlet, the lower end of the orifice sleeve is abutted against the non-sealing surface of the upper end of the valve seat, the valve cavity at the medium inlet is divided into an inner portion and an outer portion by the orifice sleeve and the valve seat, multilayer sleeves are sleeved layer by layer to form the orifice sleeve, a gap is reserved between each layer of the lower portion of the orifice sleeve, a plurality of orifices are radially reserved on the sleeve wall of each sleeve layer, and external diameter surfaces of the valve clacks are slidingly matched with the inner diameter surfaces of the orifice sleeve. The anti-air-erosion dewatering regulating valve has the advantages of no erosion, small required executive force, reliable sealability, wear resistance, washout proof, simple structure, convenient mounting, long service life and the like. Erosion can be avoided under the working condition of big differential and the anti-air-erosion dewatering regulating valve can be driven by a small actuator.

The invention relates to photo-responsive controlled-release nano-pesticide preparation and a preparation method and application thereof. A controlled-release effective constituent of the preparation is amphiphilic carboxymethyl chitosan derivative which is obtained through reaction between o-nitro benzyl hemisuccinate and carboxylmethyl chitosan. The preparation is prepared by the following steps: taking water solution of the carboxymethyl chitosan, adding organic solution of the o-nitro benzyl hemisuccinate activated by NHS and EDC.HCl according to the molar ration of sugar moiety of the carboxymethyl chitosan to the o-nitro benzyl hemisuccinate as 1 to (0.01 to 1), reacting for 6h in room temperature, then dialyzing and freeze drying to obtain photo-responsive carboxymethyl chitosan derivative, dispersing the derivative and pesticide into water at the same time and performing ultrasound at intervals to obtain photo-responsive controlled-release pesticide nanoparticle. The photo-responsive controlled-release nano-pesticide preparation can be selectively sprayed on the surfaces of or in target plants and pests under the condition free of illumination. Once the photo-responsive controlled-release nano-pesticide preparation is applied to the surfaces of or in the target plants and the pests, the photo-responsive controlled-release nano-pesticide preparation can respond external sunshine stimulation to release pesticide at any time.

Disclosed is a manufactured three-dimensional convex-concave fairing with attached vortex generators, for hydraulic structures such as bridge piers and abutments, whose shape prevents the local scour problem around such hydraulic structures. The device is a conventionally made concrete or fiber-reinforced composite, or combination of both, vortex generator equipped hydrodynamic fairing that is fit or cast over an existing or new hydraulic structure around the base of the structure and above the footing. The vortex generators are positioned so as to energize decelerating near wall flow with higher-momentum outer layer flow. The result is a more steady, compact separation and wake and substantially mitigated scour inducing vortical flow.

The invention discloses an anti-scouring construction method for a single-pile foundation of offshore wind power and belongs to the field of the construction process of offshore wind power plants. The method comprises the steps: determining an anti-scouring scope according to the installation positions of single pipe piles; paving an anti-scouring material layer in the anti-scouring scope; and installing single pipe piles on the anti-scouring material layer. The construction method solves the technical problems that the riprap project quantity is larger, the single pipe piles are seriously damaged by broken stone and the supporting stability and controllability of wind turbine generators are worse in the present construction method. And the construction method is particularly applicable to the construction of the wind power plants under the geological conditions based on sludge and powdered sandy soil.

The invention discloses an anticorrosive and wear-resistant material for the spraying zones of desulfurization towers. The material comprises an impermeable material, a reinforcing material and a wear-resistant material, wherein the impermeable material mainly comprises vinyl ester resin added with glass flakes; the reinforcing material mainly comprises vinyl ester resins, glass fiber cloth and glass fiber chopped strand mats; the wear-resistant material mainly comprises vinyl ester resin added with wear-resistant ceramic packing particles; and the wear-resistant ceramic packing particles can be divided into packing I, packing II and packing III mixed in certain proportion. The material disclosed by the invention has the advantages of low difficulty in construction, low cost, good anticorrosive effect, good wear-resistant performance, convenience in application and maintenance, and capability of effectively preventing the damage from an external force and an internal stress and resisting the corrosion of acid liquor or the erosion of flue gas, effectively resolving the problems of erosion, wear and damage of the wear-resistant material easily occurring in spraying zones of desulfurization towers, prolonging the service life of an anticorrosive layer, and greatly reducing the maintenance cost.

The invention discloses an open type top shower gating system for an air cylinder cover. The system comprises a sprue, at least one cross gate and at least one ingate, wherein one end of the cross gate communicates with the sprue while the other end of the cross gate communicates with the ingate; the sectional area ratio of the sprue to the cross gate to the ingate is that sigma F (sprue): sigma F (cross gate): sigma F (ingate)=1: (1.5-2.5): (2-3); a filter screen is arranged in the cross gate. With the adoption of the system, a produced casting is stable in quality, the rejection rate caused by cold shut, sand inclusion, slag inclusion and other defects can be greatly decreased, and moreover, the production cost can be decreased.

The production method of internal water cooling channel steel-casting is characterized by that two layers of spiral internal chill are winded round external periphery of steel pipe, in which first layer of spiral internal chill is winded round the steel pipe, and second layer of spiral internal chill is winded round first layer of spiral internal chill, at the same time, when it is poured, the low-temp. nitrogen gas is blown into the steel pipe, the nitrogen gas inlet temp. is -5- -10 deg.C, the nitrogen gas pressure is less than or equal to 0.2 MPa. After the pouring is completed, the low-temp. nitrogen gas is further blown into the steel pipe for 2-4 min. so that the steel pipe will not be melted through and can not be deformed when the molten metal whose melting point is identical to that of steel pipe is poured, therefore there is not gap or thermoresistance layer between steel pipe and base body.