Wood-plastic water supply pipeline manufacturing method and wood-plastic water supply pipeline

Abstract

The invention discloses a wood-plastic water supply pipeline manufacturing method and a wood-plastic water supply pipeline, and relates to the technical field of water supply and drainage pipes. The wood-plastic water supply pipeline manufacturing method comprises the steps that S1, wood-plastic fibers, high-density polyethylene, basalt fibers, maleic anhydride grafted polyethylene and a first additive are stirred and mixed according to the proportion, and a wood-plastic premix is manufactured; s2, the wood-plastic premix is fed into a granulator, and first particles are prepared through the granulator; s3, the first particles are put into an extruder, and a structural layer pipe blank is manufactured through the extruder; and S4, the structural layer pipe blank, the lining layer pipe blank and the outer protective layer pipe blank are compounded together, a pipeline structure is obtained, wood-plastic fibers are pure natural materials, the cost price is extremely low, recycling and reusing are achieved, the wood-plastic fibers are adopted for manufacturing the pipeline, the production cost can be remarkably reduced, and due to the fact that main components of the wood-plastic fibers are renewable biomass raw materials, the production cost is greatly reduced. And the material has excellent recoverability, so that the whole life cycle is green and environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of water supply and drainage pipe technology, and in particular to a method for manufacturing wood-plastic water supply pipes and the wood-plastic water supply pipes themselves. Background Technology

[0002] As urban construction becomes increasingly detailed and various infrastructures continue to improve, small-diameter water supply pipes, as a crucial component of the city's end-point water supply network, directly impact residents' water usage experience and the stability of the water supply. Currently, small-diameter PE (polyethylene) water supply pipes are widely used in urban end-point water supply systems. PE pipes possess a certain degree of flexibility and corrosion resistance, allowing them to adapt well to some complex laying environments.

[0003] The inherent drawbacks of traditional petroleum-based plastic pipes are becoming increasingly apparent, mainly in the following two aspects: First, petroleum-based plastics are derived from non-renewable fossil resources, and their chemical structure is stable, making them extremely difficult to degrade in the natural environment after disposal; Second, throughout the entire life cycle of crude oil extraction and refining to monomer polymerization and pipe forming, the production process of traditional PE pipes is energy-intensive and accompanied by a large amount of carbon dioxide emissions, which contradicts the concept of green and low-carbon development.

[0004] Therefore, there is an urgent need for a green, environmentally friendly, and low-cost method for manufacturing wood-plastic water supply pipes, as well as for wood-plastic water supply pipes themselves. Summary of the Invention

[0005] The purpose of this invention is to provide a method for manufacturing wood-plastic water supply pipes and a wood-plastic water supply pipe. The structural layer pipe blank of the wood-plastic water supply pipe is made of pure natural wood-plastic fiber, which reduces production costs and realizes green and environmentally friendly water supply pipes throughout their entire life cycle.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a method for manufacturing wood-plastic composite water supply pipes, comprising:

[0008] Step S1: Mix wood-plastic fiber, high-density polyethylene, basalt fiber, maleic anhydride-grafted polyethylene, and the first additive in a certain proportion to prepare wood-plastic premix.

[0009] Step S2: Feed the wood-plastic premix into the pelletizer and make the first pellets using the pelletizer;

[0010] Step S3: The first particle is put into the extruder and the structural layer tube blank is made by the extruder;

[0011] Step S4: Combine the structural layer tube blank with the inner lining layer tube blank and the outer protective layer tube blank to obtain the pipe structure.

[0012] As one embodiment, the first additive includes talc, a mildew inhibitor, a light stabilizer, and a lubricant.

[0013] As one implementation, the method further includes the following step before step S4:

[0014] High-density polyethylene is mixed with a second additive and a third additive to produce an inner layer premix and an outer layer premix, respectively.

[0015] The inner premix and the outer premix are fed into a granulator separately, and the granulator is used to make the second and third granules.

[0016] The second and third particles are fed into an extruder, and the inner liner tube blank and the outer sheath tube blank are produced by the extruder.

[0017] As one implementation method, in step S1, the mixture is stirred for 15-30 minutes at a speed of 1000-1500 r / min using a mixer to ensure that all raw materials are fully mixed.

[0018] As one embodiment, the operating temperature of the extruder is set to 180℃-240℃, and the screw speed of the extruder is set to 300-400 r / min.

[0019] As one implementation, step S2 further includes:

[0020] Step S21: The strip-shaped material extruded from the die head of the granulator is fed into the cooling tank;

[0021] Step S22: The cooled strip material is pulled to the pelletizer by the traction machine, and the pelletizer cuts the strip material into pellets according to the required particle size;

[0022] Step S23: Select particles that meet the required size using a screening machine;

[0023] Step S24: After drying, the granules that meet the size requirements are vacuum-packed for further processing.

[0024] As one embodiment, the cooling medium in the cooling tank is water, the cooling temperature is 20-30℃, and the cooling time is 10-20 minutes.

[0025] As one embodiment, the structural layer tube blank is extruded in a temperature range of 200-220°C, and the extrusion speed is maintained at 10-20m / min.

[0026] The inner lining tube blank is extruded in a temperature range of 180-200℃, and the extrusion speed is controlled at 10-20m / min.

[0027] The outer protective layer tube blank is extruded in a temperature range of 190-210℃, and the extrusion speed is controlled at 10-20m / min.

[0028] As one embodiment, in step S4, the composite molding process uses a composite temperature of 190-200℃ and a composite pressure of 10-20MPa.

[0029] The present invention also provides a wood-plastic water supply pipe, which is manufactured by the above-mentioned wood-plastic water supply pipe manufacturing method. The wood-plastic pipe includes a structural layer pipe blank, an inner lining layer pipe blank composited in the inner layer of the structural layer pipe blank, and an outer protective layer pipe blank composited in the outer layer of the structural layer pipe blank.

[0030] The present invention achieves the following technical effects compared to the prior art:

[0031] The invention discloses a method for manufacturing wood-plastic water supply pipes and the wood-plastic water supply pipes themselves. Wood-plastic fiber, high-density polyethylene, basalt fiber, maleic anhydride-grafted polyethylene, and a first additive are mixed in a specific ratio to produce a wood-plastic premix. This premix is ​​then fed into a granulator to produce first granules. These first granules are then placed into an extruder to produce a structural layer pipe blank. The structural layer pipe blank is then combined with an inner lining pipe blank and an outer protective layer pipe blank to obtain the pipe structure. Wood-plastic fiber is a purely natural material with extremely low cost and is recyclable. Using wood-plastic fiber to manufacture pipes not only significantly reduces production costs but also, because its main component is renewable biomass raw material, possesses excellent recyclability, thus achieving green environmental protection throughout its entire life cycle. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic cross-sectional view of the wood-plastic water supply pipe in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the wood-plastic water supply pipe in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the connection position of the wood-plastic pipe in an embodiment of the present invention;

[0036] Among them, 1. outer protective layer tube blank; 2. structural layer tube blank; 3. inner lining layer tube blank. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The purpose of this invention is to provide a method for manufacturing wood-plastic water supply pipes and the wood-plastic water supply pipes themselves, so as to solve the problems existing in the prior art. By using wood-plastic fiber to manufacture pipes, the production cost is low while achieving green and environmentally friendly practices throughout the entire life cycle.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Please refer to Figures 1-3 The method for manufacturing wood-plastic water supply pipes and the wood-plastic water supply pipes disclosed in this embodiment of the invention include: Step S1: mixing wood-plastic fiber (WPF), high-density polyethylene (HDPE), basalt fiber, maleic anhydride grafted polyethylene (MAPE), and a first additive in a certain proportion to prepare a wood-plastic premix; Step S2: feeding the wood-plastic premix into a granulator to produce first granules; Step S3: placing the first granules into an extruder to produce a structural layer pipe blank 2; Step S4: combining the structural layer pipe blank 2 with the inner lining pipe blank 3 and the outer sheath pipe blank 1 to obtain a pipe structure; Wood-plastic fiber is a pure natural material with extremely low cost and is recyclable. Using wood-plastic fiber as the raw material for manufacturing water supply pipes can not only significantly reduce production costs, but also, because its main component is renewable biomass raw material, it has excellent recyclability, thereby achieving green environmental protection throughout the entire life cycle.

[0041] In this embodiment, the proportion of wood-plastic fiber exceeds 50%.

[0042] In this embodiment, the first additive includes talc, a mildew inhibitor, a light stabilizer, and a lubricant.

[0043] In this embodiment, the ratio of talc powder: mildew inhibitor: light stabilizer: lubricant is 3.5:3:1.5:2. Among them, talc powder accounts for the highest proportion, which is used to improve the pipeline's resistance to soil pressure deformation and adapt to the external load requirements of the buried environment. The mildew inhibitor accounts for a medium proportion to cope with the moderately humid soil environment and inhibit the growth of microorganisms. The light stabilizer accounts for a low proportion: after being buried, the pipeline is exposed to less sunlight and only basic anti-aging protection is required. The lubricant is suitable for extrusion and ensures that the wood-plastic premix has uniform flowability in twin-screw extrusion.

[0044] In this embodiment, high-density polyethylene is used as the matrix material to provide the basic performance of the pipe, and the wood-plastic fiber has a length of 8-12 mm and a particle size of 50-130 mesh.

[0045] In this embodiment, the density of high-density polyethylene is 0.95 g / cm³. 3 Melt index 0.9 g / 10 min (190℃, 2.16 kg).

[0046] In this embodiment, the tensile strength of the basalt fiber is 3300-4500 MPa, and the elastic modulus is 90-95 GPa.

[0047] In this embodiment, the grafting rate of maleic anhydride-grafted polyethylene is 1.0%, and the melt index is 1.7 g / 10 min.

[0048] In this embodiment, before step S4, the fabrication of the inner liner tube blank 3 and the outer sheath tube blank 1 is also included: high-density polyethylene and the second additive are mixed to form an inner layer premix, and high-density polyethylene and the third additive are mixed to form an outer layer premix; the inner layer premix is ​​fed into a granulator for granulation, and the outer layer premix is ​​fed into another granulator for granulation, and the second and third particles are formed by the granulators; the second and third particles are respectively placed into two extruders for extrusion, and the inner liner tube blank 3 and the outer sheath tube blank 1 are formed by the two extruders respectively.

[0049] In this embodiment, the mixing of high-density polyethylene and the second additive, and the mixing of high-density polyethylene and the third additive, can be carried out using existing methods such as mixing with a mixer.

[0050] In this embodiment, high-density polyethylene with a thickness of 1 mm is selected as the material for the inner lining tube blank 3 and the outer sheath tube blank 1.

[0051] In this embodiment, the second additive includes talc, a mildew inhibitor, and a lubricant. The inner HDPE layer is mainly in contact with the water inside the pipe and is not directly exposed to external light, oxygen, or other oxidizing environments, so there is no need to add a light stabilizer. The ratio of talc: mildew inhibitor: lubricant is 3.5:4.5:2.

[0052] In this embodiment, the third additive includes talc, a mildew inhibitor, a light stabilizer, and a lubricant, wherein the ratio of talc: mildew inhibitor: light stabilizer: lubricant is 3:2:3:2.

[0053] In this embodiment, the ratio of wood-plastic fiber, high-density polyethylene, basalt fiber, maleic anhydride-grafted polyethylene, and additives is 6:1.5:0.5:1.5:0.5, wherein the additives include a first additive, a second additive, and a third additive.

[0054] In this embodiment, when preparing the wood-plastic premix, the mixture is stirred for 15-30 minutes at a speed of 1000-1500 r / min using a mixer to ensure that all raw materials are fully mixed.

[0055] In this embodiment, when manufacturing the structural tube blank, the working temperature of the extruder is set to 180℃-240℃, and the screw speed of the extruder is set to 300-400 r / min.

[0056] Furthermore, in the HDPE melt plasticizing process, the barrel temperature needs to follow a gradient heating strategy. Specifically, along the direction from the hopper end to the die head, based on the dynamic requirements of the material plasticizing process, a temperature increment distribution is constructed: the hopper section (feeding zone) serves as the initial preheating area for the material, with a temperature set at 180-200℃, allowing the HDPE and the blended system (including various functional additives) to achieve initial softening, providing a foundation for subsequent melting; the intermediate section (plasticizing zone) undertakes the core melting task, requiring the temperature to be raised to 200-230℃, utilizing the synergy of heat energy and screw shearing action to promote full plasticization and mixing of the material, ensuring system uniformity; the die head section (extrusion zone) needs to maintain 220-240℃, this temperature condition ensures that the material has suitable melt flowability for stable extrusion, and also maintains the integrity of the plasticized state, providing high-quality melt raw materials for molding processing.

[0057] Preferably, the extruder is a twin-screw extruder.

[0058] In this embodiment, the process of producing the first granules further includes feeding the strip-shaped material extruded from the die head of the granulator into a cooling tank. After cooling, the strip-shaped material is drawn to a pelletizer by a traction machine. The pelletizer cuts the strip-shaped material into granules according to the required particle size. The granules that meet the size requirements are then screened by a screening machine. After drying, the granules that meet the size requirements are vacuum-packed for subsequent processing.

[0059] In this embodiment, the cooling medium in the cooling tank is water, the cooling temperature is 20-30℃, and the cooling time is 10-20 minutes.

[0060] In this embodiment, the structural layer tube blank 2 is extruded in a temperature range of 200-220℃, and the extrusion speed is maintained at 10-20m / min.

[0061] In this embodiment, the inner lining tube blank 3 is extruded in a temperature range of 180-200℃, and the extrusion speed is controlled at 10-20m / min.

[0062] In this embodiment, the outer protective layer tube blank 1 is extruded in a temperature range of 190-210℃, and the extrusion speed is controlled at 10-20m / min.

[0063] In this embodiment, in step S4, the composite molding process uses a composite temperature of 190-200℃ and a composite pressure of 10-20MPa.

[0064] In this embodiment, the mechanical properties of wood-plastic composite materials obtained through experiments are detailed in Table 1. Table 1 shows the various mechanical properties of wood-plastic composite materials obtained through experiments.

[0065] Table 1

[0066]

[0067] In this embodiment, the method for manufacturing wood-plastic water supply pipes also includes calculating the thickness. First, the nominal wall thickness of the wood-plastic water supply pipe is determined. This work is based on the mechanical properties of wood-plastic materials and the requirements of the pressure-bearing mechanical properties of the PE pipes of the same specification that are to be replaced.

[0068] Wood-plastic composite pipe nominal wall thickness e n The calculation formula is:

[0069]

[0070] Where: e n —Nominal wall thickness;

[0071] d n —Nominal diameter;

[0072] p—pressure inside the pipe;

[0073] f wpc,t —Design value of tensile strength for wood-plastic composite pipes;

[0074] f wpc,tk —Standard value of tensile strength for wood-plastic composite pipes;

[0075] γ wpc —Partial factor for wood-plastic composite materials, with a value of 1.2 to 1.4;

[0076] In this embodiment, the method for manufacturing wood-plastic water supply pipes also includes strength verification under ground load and vehicle load, and the maximum allowable circumferential pressure F of the pipe wall section. cr,k If F is satisfied cr,k If the value is greater than or equal to the maximum value of {F1, F2}, it can be determined that the strength calculation result of the pipe material meets the design and relevant specifications. Here, F1 and F2 are the external pressure under the action of ground accumulation load and the external pressure under the action of vehicle load, respectively.

[0077] The formula for calculating the circumferential pressure of the wood-plastic pipe wall section is:

[0078]

[0079] Where: E p—Circumferential elastic modulus of wood-plastic composite pipes;

[0080] E d —Comprehensive deformation modulus of soil along the pipe;

[0081] n—crease number, n≥2, n takes the value of 2;

[0082] v p —Poisson's ratio of wood-plastic composite pipes;

[0083] v s —Poisson ratio of backfill soil.

[0084] External pressure F1 under ground accumulator load:

[0085]

[0086] Where: K st —Circumferential stability resistance coefficient, K st Take 2;

[0087] F sv,k —Vertical earth pressure;

[0088] q mk —Ground load;

[0089] F vk —Vacuum pressure, take 0.05MPa.

[0090] Vertical earth pressure calculation F sv,k :

[0091]

[0092] Where: C d / C c —Earth pressure coefficient for trenching / earth pressure coefficient for embankment construction, take = 1.2;

[0093] r s —Unit weight of backfill soil;

[0094] H s —Elevation of soil cover;

[0095] D1—Diameter of the outer wall of the pipe.

[0096] External pressure F2 under vehicle load:

[0097]

[0098] Where: q vk —Vehicle load.

[0099] Vehicle load calculation:

[0100]

[0101] Where: n — number of wheels;

[0102] Q vk —Standard values ​​for vehicle load;

[0103] μ d —μ d Take 1;

[0104] a—Length of a single wheel's contact patch;

[0105] b—Width of a single wheel;

[0106] z—distance from the ground level to the top of the pipe;

[0107] d1, d2, d3 — the net distance between different wheels.

[0108] Deformation verification under ground accumulator load and vehicle load

[0109] The maximum permissible long-term vertical deflection value w of the pipe d For w d =0.05×d n If w is satisfied d ≥max{w d1,max ,w d2,max}, it can be determined that the pipe deformation calculation results meet the design and relevant specification requirements, where w d1,max ,w d2,max These are the maximum long-term vertical deformation under ground accumulation load and the maximum long-term vertical deformation under vehicle load, respectively.

[0110] Maximum long-term vertical deformation w under ground accumulation load d1,max :

[0111]

[0112] Where: D L —Hysteresis deformation effect, taken as 1.5;

[0113] ψ q —Vehicle reduction factor, taken as 0.5;

[0114] D1—Diameter of the outer wall of the pipe;

[0115] k d —Vertical deformation coefficient under vertical pressure, taken as 0.096;

[0116] S P —Ring stiffness of wood-plastic composite pipes.

[0117] k dThe value can be found in Table 2, which shows the vertical deformation coefficient of the pipeline under vertical load.

[0118] Table 2

[0119]

[0120] The ring stiffness S of wood-plastic pipe P Calculation:

[0121]

[0122] Where: e n —Nominal wall thickness;

[0123] d n —Nominal outer diameter.

[0124] Maximum long-term vertical deformation w under vehicle load d2,max :

[0125]

[0126] First, define the cross-sectional dimensions of the wood-plastic composite material, the nominal outer diameter d. n =Rmm, derived from the Standard Dimension Ratio (SDR) formula SDR = d n / e n The nominal wall thickness e of the wood-plastic composite pipe can be obtained. n .

[0127] Nominal wall thickness e of the pipe n It should comply with the provisions in Table 3, which shows the nominal wall thickness of PE pipes.

[0128] Table 3

[0129]

[0130] Other standard size ratios calculated according to the pipe series specified in GB / T10798 and GB / T4217 are permitted. The minimum required strength (MRS) is determined and extrapolated from the pipe material. Note: The relationship between PN, MRS, S, and SDR is shown in Table 4, which shows the relationship between PN, MRS, S, and SDR for PE pipes at 20℃.

[0131] Table 4

[0132]

[0133] In this embodiment, the dimensions of the wood-plastic water supply pipe are selected as follows: nominal outer diameter d. n The nominal wall thickness is 560mm. Based on Tables 3 and 4, SDR = 17 and S = 8 are selected, corresponding to a nominal wall thickness e. nIt has a diameter of 33.2 mm, an inner diameter d of 526.8 mm, and a nominal pressure of PN(PE80) = 0.8 MPa.

[0134] According to Table 1, the standard value of its tensile strength perpendicular to the extrusion direction is f. wpc,tk =10.45MPa, according to the partial factor γ bpc The design value of the tensile strength perpendicular to the extrusion direction is obtained from formula (1-2) as f. wpc,t =10.00MPa. Based on formula (1-1), the maximum internal pressure that the pipe can withstand under its tensile strength in the perpendicular extrusion direction is calculated:

[0135]

[0136] According to national standards, SDR = 17 and S = 8, corresponding to a nominal pressure of PN(PE80) = 0.8 MPa. Therefore, the ratio of the maximum internal pressure of the pipe perpendicular to the extrusion direction to the nominal pressure under the corresponding conditions is:

[0137]

[0138] Given that this ratio is greater than 1, preliminary calculations indicate that small-diameter wood-plastic composite (WPC) water supply pipes, with WPC as the core material, can replace small-diameter PE water supply pipes under equal cross-sectional conditions. This result theoretically confirms that small-diameter WPC water supply pipes meet mechanical requirements and possess corresponding reliability. Based on this, subsequent calculations will be conducted on the minimum cross-sectional dimensions achievable by WPC pipes under operating conditions that meet the nominal pressure requirements of the design.

[0139] With nominal diameter d n Taking a 560mm PE pipe design as an example, calculations are performed using wood-plastic composite as the main core material. Based on Tables 1 and 2, SDR=17 and S=8 are selected, with the corresponding nominal wall thickness e... n It has a diameter of 33.2 mm, an inner diameter d of 526.8 mm, and a nominal pressure of PN(PE80) = 0.8 MPa.

[0140] Given that the nominal pressure PN (PE80) = 0.8 MPa, and the design tensile strength value is f wpc,t =10.00MPa. Calculate the Standard Dimension Ratio (SDR) according to formula (1-1). Note: Different SDR values ​​correspond to different pressure-bearing capacities. The smaller the SDR value, the thicker the pipe wall and the higher the pressure it can withstand; conversely, the larger the SDR value, the thinner the pipe wall and the lower the pressure it can withstand.

[0141]

[0142] The corresponding nominal wall thickness can be calculated from the calculated SDR value.

[0143]

[0144] Based on the calculation results, under the corresponding design conditions, the nominal wall thickness e of PE small-diameter pipes n The nominal wall thickness is 33.2 mm, while the nominal wall thickness e of wood-plastic composite pipes is... n,b Only 22.4mm, i.e., e n,b <e n This data shows that wood-plastic composite pipes require less material to achieve the same or even better mechanical properties. Under operating conditions that meet the nominal pressure requirements of the design, wood-plastic composite pipes, thanks to their excellent mechanical properties, can achieve stable operation with thinner walls, fully demonstrating their greater potential in terms of material utilization efficiency and mechanical performance.

[0145] After comparing the mechanical properties of the two materials, the strength and deformation of the wood-plastic composite pipe structure in this embodiment will be calculated separately.

[0146] In this embodiment, the wood-plastic composite pipe is buried 2m below the seabed with soil cover. The designed ground elevation is 2.0m, the pipe top burial depth is -0.0337m, and the soil cover elevation is H. s =Design ground elevation +|Pipe top burial depth elevation| = 2.0337m.

[0147] Strength verification under ground accumulator load and vehicle load

[0148] Unit weight of backfill soil (r) s =18kN / m 3 Vertical earth pressure F sv,k Calculate according to formula (1-5):

[0149] Then F sv,k =1.2×18×2.0337×560×0.001≈24.60kN / m.

[0150] In this embodiment, n = 4, Q vk According to the "Code for Design of Urban Bridges" (CJJ11-2011), the value is taken as 10.5 kN / m, the ground contact length of a single wheel is a = 0.2 m, the width of a single wheel is b = 0.6 m, and z = H. s = 2.0337m, d1, d2, and d3 are taken as 1.8m, 1.3m, and 1.8m respectively. According to formula (1-7), the vehicle load is calculated as follows:

[0151]

[0152] Based on experiments, the elastic modulus v of the wood-plastic pipe in the embodiment was obtained. p The Poisson's ratio of the backfill soil is 0.41, v. sThe value is 0.4. F can be calculated using formula (1-3). cr,k

[0153]

[0154] Based on experiments, the elastic modulus E of the wood-plastic pipe in the embodiment was obtained. p 3.78×10 9 MPa, ground accretion load q mk 180kN / m 2 Comprehensive deformation modulus E of the soil along the pipe d It is 7.530 MPa. The vacuum pressure is F. vk =0.05MPa, F1 is calculated according to formula (1-4)

[0155]

[0156] F2 is calculated according to formula (1-6)

[0157]

[0158] The maximum permissible circumferential pressure F of the pipe wall section cr,k =2.79MPa, its F cr,k If the result is greater than or equal to the maximum value of F1 and F2, it can be determined that the strength calculation of the pipe meets the design and relevant specifications.

[0159] Deformation verification under ground accumulator load and vehicle load

[0160] The ring stiffness S of wood-plastic pipes calculated according to formulas (1-8) and (1-9) P The maximum long-term vertical deformation w under ground accumulation load d1,max

[0161]

[0162] The maximum long-term vertical deformation w under vehicle load is calculated according to formula (1-10). d2,max

[0163]

[0164] The maximum permissible long-term vertical deflection value w of the pipe d for:

[0165] w d =0.05×d n =0.05×560=28mm, its ω d ≥max{w d1,max ,w d2,maxIt can be determined that the pipe deformation calculation results meet the design and relevant specification requirements.

[0166] Therefore, it was verified that the wood-plastic composite pipe in this embodiment meets the strength and deformation requirements of relevant specifications when replacing PE pipe with the same cross-section and applying corresponding external pressure.

[0167] For the remaining parts of Table 3, under the condition of meeting the design requirements, the minimum standard dimension ratios (SDRs) of all wood-plastic composite materials were further calculated, as shown in Table 5. Table 5 is a comparison table of the minimum SDRs of wood-plastic composite pipes and PE pipes under the condition of meeting the design requirements. Under the nominal pressure conditions that meet the design requirements, wood-plastic composite pipes, with their good mechanical properties, can operate stably with thinner wall thicknesses, and have higher potential in terms of material utilization efficiency and mechanical performance.

[0168] Table 5

[0169]

[0170] In this embodiment, after completing the corresponding cross-sectional inspection of the wood-plastic composite composite pipe structure, an economic comparison analysis is conducted between it and PE pipes, as shown in Table 6. Table 6 is a price comparison table of PE pipe and wood-plastic composite composite pipe per meter.

[0171] Table 6

[0172]

[0173] The density of PE80 grade PE pipe is 0.95 g / cm³. 3 The price is 10 yuan per kilogram, and the density of the wood-plastic composite pipe is 1.3 g / cm³. 3 The processing cost of the two materials is set at 5 yuan per kilogram, and the average processing cost C1 is set at 75 yuan.

[0174] Taking the wood-plastic composite pipe with the largest nominal diameter in this embodiment as an example, the pipe cost C under the condition of the largest nominal wall thickness is calculated in the order of volume, mass, and cost. max .

[0175]

[0176] m max =ρ×V max (2-2)

[0177] C max =m max ×p+C1 (2-3)

[0178] The method for calculating the cost of pipes with the smallest nominal diameter is the same and will not be repeated here.

[0179] As shown in Table 6, the price per meter of wood-plastic composite pipes is lower than that of PE80 grade PE pipes under different nominal diameter specifications, and even reaches 1 / 3 to 1 / 2 of the price of PE pipes, highlighting the price advantage of wood-plastic pipes.

[0180] This invention also discloses a wood-plastic water supply pipe, which is manufactured using the above-mentioned wood-plastic water supply pipe manufacturing method. The wood-plastic pipe includes a structural layer pipe blank 2, an inner lining layer pipe blank 3 composited in the inner layer of the structural layer pipe blank 2, and an outer protective layer pipe blank 1 composited in the outer layer of the structural layer pipe blank 2.

[0181] In this embodiment, the small-diameter wood-plastic water supply pipe adopts an innovative snap-fit ​​and environmentally friendly resin adhesive bonding technology, which is convenient to operate and has a firm connection. It can quickly complete the pipe splicing, greatly shorten the construction cycle, reduce labor costs, and has excellent sealing performance, which can effectively resist water pressure changes and external stress, ensuring long-term stable operation.

[0182] In this embodiment, the small-diameter wood-plastic water supply pipe is connected using a combination of snap-fit ​​connections and environmentally friendly resin adhesive. The high-strength snap-fit ​​connection is simple and quick to operate, enabling rapid pipe splicing, significantly shortening the construction cycle and reducing labor costs. The environmentally friendly resin adhesive offers excellent sealing and corrosion resistance, effectively solving the problems of leakage and poor durability in traditional pipes, reducing water waste and pipe maintenance frequency. This design ensures the overall strength of the pipe while greatly saving on-site construction time, contributing to the efficient and stable operation of urban end-point water supply systems.

[0183] In this embodiment, a complete piping system is constructed using a composite connection method combining sleeve butt joints and non-toxic epoxy resin bonding. This connection method employs a structural design combining sleeve butt joints and non-toxic epoxy resin bonding. First, the end faces of the two pipes are aligned and kept flush. Then, an HDPE sleeve matching the outer diameter of the pipes is fitted externally, forming a ring-shaped wrapping structure. The gaps between the pipe joints and the connection between the sleeve and the pipes are filled and bonded using non-toxic epoxy resin adhesive certified for drinking water safety. This adhesive must possess excellent bonding strength (≥10MPa), water resistance (strength retention rate ≥90% after long-term immersion), and environmental friendliness (compliant with GB / T17219 standard). After the adhesive cures, a uniform sealing layer is formed at the connection point. Through the dual action of mechanical wrapping and chemical bonding, the connection strength and leak-proof performance are ensured.

[0184] In this embodiment, a complete piping system is constructed using a hot-melt socket-sleeve-non-toxic epoxy resin composite connection method. Based on the hot-melt socket principle, this connection method first processes the two pipe ends to be connected into a socket and spigot structure, wherein the inner diameter of the socket is 1.5-2.0 mm larger than the outer diameter of the spigot, and the contact surface is milled to form a rough surface (roughness R). aThe diameter of the spigot is ≤12.5μm, and a 45° chamfer is processed. The inner wall of the socket and the outer wall of the spigot are simultaneously heated to the HDPE melting temperature (210±10℃) using a special heating tool, with the melting depth controlled at 1.0~1.5mm. Then, the spigot is quickly inserted and axial pressure is maintained for 5~10 minutes to ensure complete fusion of the molten materials at the contact surfaces. After the hot-melt joint cools, an HDPE sleeve is fitted externally, and non-toxic epoxy resin is filled into the gap between the sleeve and the pipe, forming a composite sealing structure of the hot-melt layer and the adhesive layer. This design combines the physical fusion of the hot-melt socket with the chemical bonding of epoxy resin, significantly improving the integrity and impermeability of the connection interface, meeting the safety performance requirements of drinking water pipelines.

[0185] In this embodiment, the inner lining tube blank 3 and the outer sheath tube blank 1 are also referred to as HDPE layers.

[0186] In this embodiment, bamboo powder is used instead of wood-plastic fiber to make wood-plastic water supply pipes.

[0187] It is understandable that: nominal outer diameter refers to the outer diameter of the wood-plastic water supply pipe, nominal inner diameter refers to the inner diameter of the wood-plastic water supply pipe, and nominal wall thickness refers to the wall thickness of the wood-plastic water supply pipe.

[0188] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for manufacturing a wood plastic water supply pipe, characterized in that, The application relates to a wood-plastic water supply pipeline manufacturing method. The first additive comprises talcum powder, mildew-proof agent, light stabilizer and lubricant. Before step S4, the method further comprises: The high-density polyethylene is mixed with the second additive and the third additive respectively to prepare inner-layer premix and outer-layer premix; The inner-layer premix and the outer-layer premix are respectively fed into a granulator to prepare second particles and third particles through the granulator; 2. The method of claim 1, wherein, The second particles and the third particles are respectively put into an extruder to prepare the inner lining pipe blank (3) and the outer protective layer pipe blank (1) through the extruder.

3. The method for manufacturing wood-plastic water supply pipes according to claim 1, characterized in that, In step S1, the mixer is stirred at a speed of 1000-1500 r / min for 15-30 minutes to ensure that the raw materials are fully mixed. The working temperature of the extruder is set to 180-240 DEG C, and the rotating speed of the screw rod of the extruder is set to 300-400 r / min. The step S2 further comprises: Step S21: the strip-shaped material extruded from the die head of the granulator is sent into a cooling tank; 4. The method of claim 1, wherein the wood plastic water supply pipe is made by the steps of: preparing a wood plastic composite material; extruding the wood plastic composite material into a pipe shape; and cutting the pipe shape into a predetermined length. Step S22: the cooled strip-shaped material is pulled to a pelletizer by a pulling machine, and the strip-shaped material is cut into particles according to the required particle size; 5. The method for manufacturing wood-plastic water supply pipes according to claim 1, characterized in that, Step S23: the particles with qualified sizes are screened through a screening machine; 6. The method for manufacturing wood-plastic water supply pipes according to claim 1, characterized in that, Step S24: the particles with qualified sizes are vacuum packaged after drying treatment for subsequent treatment. The cooling medium in the cooling tank is water, the cooling temperature is 20-30 DEG C, and the cooling time is 10-20 min. The structure layer pipe blank (2) is extruded at a temperature of 200-220 DEG C, and the extrusion speed is kept at 10-20 m / min; The inner lining pipe blank (3) is extruded at a temperature of 180-200 DEG C, and the extrusion speed is controlled at 10-20 m / min; The outer protective layer pipe blank (1) is extruded at a temperature of 190-210 DEG C, and the extrusion speed is controlled at 10-20 m / min.

7. The method for manufacturing wood-plastic water supply pipes according to claim 6, characterized in that, In step S4, the composite temperature used in the composite forming process is 190-200 DEG C, and the composite pressure is 10-20 MPa.

8. The method for manufacturing wood-plastic water supply pipes according to claim 3, characterized in that, The wood-plastic water supply pipeline is manufactured by the wood-plastic water supply pipeline manufacturing method in any one of claims 1-9. ​ ​ 9. The method for manufacturing wood-plastic water supply pipes according to claim 1, characterized in that, ​ 10. A wood plastic water supply pipe, characterized by, ​

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