Lead-free PVC (polyvinyl chloride) well digging pipe fitting and preparation method thereof

Abstract

According to the lead-free PVC well digging pipe fitting and the preparation method thereof, a 45-degree chamfer structure is arranged at the front end of a finished product of the prepared PVC well digging pipe fitting, and the friction force between the pipe fitting driven into the ground and soil and gravel can be reduced; the prepared PVC well digging pipe fitting has compression resistance, wear resistance and corrosion resistance, the preparation method is simpler, the cost is low, well digging pipe connection can be completed without other auxiliary accessories, meanwhile, it is guaranteed that the pipe fitting is not broken, and the PVC well digging pipe fitting can meet the use requirements of various water qualities and complex environments and is suitable for popularization and application. The corrosion resistance and the wear resistance of the pipe fitting are improved, the durability of the well digging pipe fitting in acid, sand-containing and other complex environments is improved, the service life of the pipe fitting is prolonged, and the pipe fitting is worthy of application and popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of well drilling pipe fittings, in particular to a lead-free PVC well drilling pipe fitting and a preparation method thereof. Background Art

[0002] The deep well pipe industry is an important supporting industry in my country's oil, natural gas, geological exploration and other fields. With the acceleration of the country's industrialization process, especially the continuous growth of energy demand such as oil and natural gas, the deep well pipe industry has developed rapidly. Well drilling pipe fittings are key accessories used in water well drilling, dewatering, filtration and other projects. They need to have resistance to internal pressure, external pressure and corrosion. Existing well drilling pipe fittings are mostly made of steel, cement, plastic or other composite materials. Steel has high pressure, high strength and corrosion resistance, but the cost is relatively high. PE material is suitable for low-pressure water transmission and has good flexibility, but has low pressure resistance. Cement pipes are low-cost and suitable for shallow water wells and farmland irrigation, but they are heavy, prone to aging, and have high maintenance costs. Other materials such as carbon fiber and other lightweight designs are still in the research and development stage and have not yet been widely used.

[0003] In addition, when existing well drilling pipes and pipes are installed downward, the infiltration of foreign matter such as sand and gravel will cause damage and breakage of the pipes. Usually, the service life of the well drilling pipes is improved by increasing the wall thickness of the pipes or designing a reinforcing rib structure.

[0004] Therefore, a lead-free PVC well-drilling pipe fitting and a preparation method thereof are provided, which uses a simpler method to prepare the well-drilling pipe fitting and makes it easy to install, meets the use requirements of various water qualities and complex environments, improves the corrosion resistance and wear resistance of the pipe fitting, and improves the durability of the well-drilling pipe fitting in complex environments such as acidic and sandy environments, which becomes a direction for further improvement. Summary of the Invention

[0005] The purpose of the present invention is to provide a lead-free PVC well drilling pipe and a preparation method thereof, so as to effectively solve the technical problems existing in the above-mentioned background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solutions.

[0007] A lead-free PVC well-drilling pipe fitting, characterized in that the PVC well-drilling pipe fitting is made of the following raw materials in parts by weight:

[0008] PVC: 100 parts, calcium zinc stabilizer: 3-7 parts, impact modifier: 2-6 parts, processing aid ACR: 2-6 parts, titanium dioxide: 1-3 parts, internal lubricant: 1-2 parts, external lubricant: 1-2 parts, nano calcium: 15-22 parts, heavy calcium carbonate powder: 5-8 parts.

[0009] Preferably, the PVC well drilling pipe is made of the following raw materials in parts by weight: PVC: 100 parts, calcium zinc stabilizer: 4 to 5 parts, impact modifier: 3 to 5 parts, processing aid ACR: 2 to 4 parts, titanium dioxide: 1 to 3 parts, internal lubricant: 1 to 2 parts, external lubricant: 1 to 2 parts, nano calcium: 18 to 20 parts, and heavy calcium carbonate powder: 6 to 7 parts.

[0010] Preferably, the internal lubricant is stearic acid wax, and the external lubricant is PE wax.

[0011] A method for preparing a lead-free PVC well drilling pipe fitting, characterized by comprising the following steps:

[0012] S1. Mix all the raw materials of the weight components, knead and disperse them, heat the raw materials to 110°C to 120°C and then perform low-speed hot mixing;

[0013] S2, based on S1, automatically discharges the hot mixed raw materials into the cold mixing pot, and the mixed raw materials are cooled to 50℃~55℃, discharged into the transfer bin and then sucked into the granulator;

[0014] S3: Based on S2, the granulator extrude, cut and granulate the mixed raw materials, cool them, and sort and select them through a vibration screen to form granular and flake materials. The granular materials are pumped into the injection molding machine.

[0015] S4. Based on S3, the injection molding machine plasticizes the material and performs injection pressure maintenance. After cooling and shaping, the material is demoulded to obtain the finished PVC well drilling pipe fittings.

[0016] Preferably, a 45° bevel is provided in the mold cavity of the injection molding machine, so that the front end of the finished PVC well drilling pipe has a 45° chamfer.

[0017] Preferably, in step S4, the injection time is 13 to 15 seconds, and the pressure holding time is 2 to 3 seconds.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The PVC well-drilling pipe fittings prepared by the present invention are provided with a 45° chamfer structure at the front end of the finished product, which can reduce the friction between the pipe fittings and the soil and gravel when they are driven into the ground; and the PVC well-drilling pipe fittings prepared by the present invention have the properties of pressure resistance, wear resistance and corrosion resistance, the preparation method is simpler and the cost is low, and the connection of the well-drilling pipes can be completed without other auxiliary accessories, while ensuring that the pipes and fittings are not broken. The present invention can meet the use requirements of various water qualities and complex environments, improve the corrosion resistance and wear resistance of the pipe fittings, improve the durability of the well-drilling pipe fittings in complex environments such as acidic and sandy environments, and increase the service life of the pipe fittings, and is worthy of promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of the PVC well drilling pipe of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] In the description of the present invention, unless otherwise specified, "plurality" means two or more; terms such as "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," and "tail" indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0024] Example 1

[0025] PVC well drilling pipe fittings are made of the following raw materials in parts by weight:

[0026] PVC: 100 parts, calcium zinc stabilizer: 3 parts, impact modifier: 3 parts, processing aid ACR: 4 parts, titanium dioxide: 2 parts, internal lubricant: 1 part, external lubricant: 2 parts, nano calcium: 15 parts, heavy calcium carbonate powder: 8 parts.

[0027] The internal lubricant is stearic acid wax, which increases the wrinkle resistance of the finished PVC well-drilling pipe fittings, and the external lubricant is PE wax, which makes the finished PVC well-drilling pipe fittings easier to demould.

[0028] The preparation method of lead-free PVC well drilling pipe fittings is characterized by comprising the following steps:

[0029] S1. Mix all the raw materials of the weight components, knead and disperse them, heat the raw materials to 110°C to 120°C and then perform low-speed hot mixing;

[0030] S2, based on S1, automatically discharges the hot mixed raw materials into the cold mixing pot, and the mixed raw materials are cooled to 50℃~55℃, discharged into the transfer bin and then sucked into the granulator;

[0031] S3: Based on S2, the granulator extrude, cut and granulate the mixed raw materials, cool them, and sort and select them through a vibration screen to form granular and flake materials. The granular materials are pumped into the injection molding machine.

[0032] S4. Based on S3, the injection molding machine plasticizes the material and performs injection pressure maintenance. After cooling and shaping, the material is demoulded to obtain the finished PVC well drilling pipe fittings.

[0033] A 45° bevel is set in the mold cavity of the injection molding machine, so that the front end of the finished PVC well drilling pipe has a 45° chamfer.

[0034] like Figure 1 As shown, the PVC well-drilling fittings produced by the present invention are generally similar to a bundled joint structure. Based on this bundled joint structure, a 45° chamfer is designed at the top of the front end of the fitting, effectively reducing the resistance of sand and gravel during well-drilling construction, avoiding the risk of pipe and fitting rupture during construction. Furthermore, a step is provided in the middle of the finished well-drilling fitting for inserting subsequent pipe connections, preventing interference between the ends of the pipe in the well-drilling fitting during subsequent connection. This further facilitates burial in the soil after connecting the pipe to the pipe.

[0035] In step S4, the injection time is 13 to 15 seconds, and the pressure holding time is 2 to 3 seconds.

[0036] Since the present invention is a lead-free formula and belongs to environmentally friendly materials, the calcium zinc stabilizer used in the present invention does not contain lead components, thereby improving environmental friendliness and environmental performance. The physical and chemical performance indicators of the calcium zinc stabilizer are shown in Table 1 below:

[0037] project index Volatile matter content% R≤4.0 Calcium content% R±2.5 Zinc content% R±2.5 Heating loss% R±4 Residue on ignition % R±5 Color change test (iron ion) Not redder than the benchmark sample

[0038] The physical and chemical performance indicators of the impact modifier are shown in Table 2 below:

[0039]

[0040]

[0041] Example 2

[0042] The difference between this embodiment and embodiment 1 is that:

[0043] The PVC well drilling pipe fittings of this embodiment are made of the following raw materials in parts by weight: PVC: 100 parts, calcium zinc stabilizer: 4 parts, impact modifier: 6 parts, processing aid ACR: 3 parts, titanium dioxide: 2 parts, internal lubricant: 2 parts, external lubricant: 1 part, nano calcium: 18 parts, and heavy calcium carbonate powder: 5 parts.

[0044] Example 3

[0045] The difference between this embodiment and embodiment 1 is that:

[0046] The PVC well drilling pipe fittings of this embodiment are made of the following raw materials in parts by weight: PVC: 100 parts, calcium zinc stabilizer: 4 parts, impact modifier: 5 parts, processing aid ACR: 4 parts, titanium dioxide: 3 parts, internal lubricant: 2 parts, external lubricant: 2 parts, nano calcium: 20 parts, and heavy calcium carbonate powder: 7 parts.

[0047] Example 4

[0048] The difference between this embodiment and embodiment 1 is that:

[0049] The PVC well drilling pipe fittings of this embodiment are made of the following raw materials in parts by weight: PVC: 100 parts, calcium zinc stabilizer: 5 parts, impact modifier: 4 parts, processing aid ACR: 2 parts, titanium dioxide: 1-3 parts, internal lubricant: 2 parts, external lubricant: 2 parts, nano calcium: 19 parts, and heavy calcium carbonate powder: 6 parts.

[0050] For Examples 1-4 of the present invention, the applicant conducted the following tests and also added two control groups for comparative experiments. The control groups were plastic well drilling pipes of two different brands purchased randomly on the market. The experimental results of the relevant items tested under the same experimental conditions are shown in Table 3 below:

[0051]

[0052] As shown in Table 3 above, the appearance of Example 1 of the present invention is slightly flawed, while the appearance of Examples 2-4 is intact; the appearance of Control Groups 1 and 2 is also slightly flawed;

[0053] Since the front end of Example 1-4 has a 45° chamfer, it can achieve better combined effect when used in conjunction with other pipe fittings, and the density of the PVC well-drilling pipe fittings prepared by the preparation method of the present invention is relatively uniform, and the oven test, cold drop test, dichloromethane immersion test and salt spray test are all qualified. Therefore, the PVC well-drilling pipe fittings prepared by the present invention have pressure resistance, wear resistance and corrosion resistance, while ensuring that the pipes and fittings will not break, can meet the use requirements of various water qualities and complex environments, improve the corrosion resistance and wear resistance of the pipe fittings, improve the durability of the well-drilling pipe fittings in complex environments such as acidic and sandy environments, and improve the service life of the pipe fittings.

[0054] The control group 1 failed the dichloromethane immersion test and the salt spray test, so the service life of the pipe fittings is not long and they are not suitable for installation environments such as saline-alkali land; the control group 2 failed the oven test, cold drop test and dichloromethane immersion test, so the service life of the pipe fittings is also relatively limited, the pressure resistance is low, and they are prone to aging, and are not suitable for installation environments such as saline-alkali land.

[0055] The test results of different chamfer angles on the finished PVC well-drilling pipes of Examples 1-4 are shown in Table 4 below:

[0056]

[0057] As shown in Table 2, different chamfers are made on the front ends of the finished PVC well-drilling pipe fittings of Examples 1-4. When the chamfer of the front end of the PVC well-drilling pipe fitting is 30°, the water pressure test of Examples 1-4 only barely passes the sealing performance. When the pressure fluctuates, slight leakage will still occur, which is not suitable for large-area laying; when the chamfer of the front end of the PVC well-drilling pipe fitting is 60°, the local sealing of Examples 1-4 is not tight, affecting normal use; when the chamfer of the front end of the PVC well-drilling pipe fitting is 45°, the water pressure test of Examples 1-4 passes, and the average tensile force in the tensile test and the average tensile force in the fracture test are both greater than the average tensile force when the chamfer is 30° / 60°. When the chamfer of the front end of the PVC well-drilling pipe fitting is 45°, the product made by the present invention has better reliability.

[0058] The preparation method of the present invention is simpler and low-cost. It can complete the connection of well drilling pipes without other auxiliary accessories, does not need to deliberately increase the wall thickness, and has better pressure resistance and sealing properties. It is suitable for more installation scenarios and is worthy of promotion and use.

[0059] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of rights of the present invention. Therefore, modifications, equivalent changes, improvements, etc. made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A lead-free PVC well drilling pipe, characterized in that: The PVC well drilling pipe is made of the following raw materials in parts by weight: PVC: 100 parts, calcium zinc stabilizer: 3-7 parts, impact modifier: 2-6 parts, processing aid ACR: 2-6 parts, titanium dioxide: 1-3 parts, internal lubricant: 1-2 parts, external lubricant: 1-2 parts, nano calcium: 15-22 parts, heavy calcium carbonate powder: 5-8 parts.

2. The lead-free PVC well drilling pipe according to claim 1, characterized in that: The PVC well drilling pipe fittings are made of the following raw materials in parts by weight: 100 parts of PVC, 4 to 5 parts of calcium zinc stabilizer, 3 to 5 parts of impact modifier, 2 to 4 parts of processing aid ACR, 1 to 3 parts of titanium dioxide, 1 to 2 parts of internal lubricant, 1 to 2 parts of external lubricant, 18 to 20 parts of nano calcium, and 6 to 7 parts of heavy calcium carbonate powder.

3. The lead-free PVC well drilling pipe according to claim 2, characterized in that: The internal lubricant is stearic acid wax, and the external lubricant is PE wax.

4. The method for preparing a lead-free PVC well-drilling pipe according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Mix all the raw materials of the weight components, knead and disperse them, heat the raw materials to 110°C to 120°C and then perform low-speed hot mixing; S2, based on S1, automatically discharges the hot mixed raw materials into the cold mixing pot, and the mixed raw materials are cooled to 50℃~55℃, discharged into the transfer bin and then sucked into the granulator; S3: Based on S2, the granulator extrude, cut and granulate the mixed raw materials, cool them, and sort and select them through a vibration screen to form granular and flake materials. The granular materials are pumped into the injection molding machine. S4. Based on S3, the injection molding machine plasticizes the material and performs injection pressure maintenance. After cooling and shaping, the material is demoulded to obtain the finished PVC well drilling pipe fittings.

5. The method for preparing a lead-free PVC well-drilling pipe according to claim 4, characterized in that: A 45° inclined surface is arranged in the mold cavity of the injection molding machine, so that the front end of the finished PVC well drilling pipe has a 45° chamfer.

6. The method for preparing a lead-free PVC well-drilling pipe according to claim 4, characterized in that: In step S4, the injection time is 13 to 15 seconds, and the pressure holding time is 2 to 3 seconds.

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