WO2009030085A1

WO2009030085A1 - Protecting device of threads on tube end

Info

Publication number: WO2009030085A1
Application number: PCT/CN2007/070624
Authority: WO
Inventors: Lianji Sun; Zhenxiang Jia
Original assignee: Lianji Sun
Priority date: 2007-09-05
Filing date: 2007-09-05
Publication date: 2009-03-12

Abstract

A protecting device of the threads on the tube end includes a cylindrical rigid frame (1) provided with a flange on one end and a housing fitted together with the rigid frame (1) and provided with an indented back cover; threads (4) are provided on the side periphery of said housing; said threads (4) match with the threads on the tube end; ribs (5) are provided on the side periphery of the cylindrical rigid frame (1); and said housing is fitted with the cylindrical rigid frame (1) by stepped injecting molding process. It has rational structure, can not easily contract and deform, can resist the change of high and low temperature, and has high precision of the dimension. It improves the ability of anti-impact, can avoid shedding, save energy and can be intensively spread and applied.

Description

Steel pipe end thread protection device and preparation method thereof

The invention relates to a pipeline protection device and a preparation method thereof, in particular to a protection device for internal and external threads of an end portion of a steel pipe and a preparation method thereof. Background technique

Usually, the pipe is made up of a section of pipe, according to the needs of the project, such as oil pipelines, etc., because both ends of the pipe are provided with internal and external threads for interconnection, generally in transportation The threads of the tube head are protected during the process. The thread protectors used in the prior art for various pipe ends are mainly composed of all steel or full plastic or steel-plastic composite structures. All-steel thread protector, because its threaded parts are not treated with flexibility, it is easy to damage the thread at the end of the pipe when transporting or disassembling, in case of excessive external impact force; Due to the poor strength, in the case of excessive external impact force or temperature change during transportation or disassembly, it is easy to cause its own deformation, which may cause it to be removed or weakened due to its deformation. . In order to overcome these defects, the relevant personnel developed a steel-plastic combined thread protector, which is mainly composed of a steel ring layer and a plastic layer, and is formed by a single injection molding plastic layer on the surface or inner layer of the steel ring layer. The disadvantages of this type of injection molded product are that it is easy to shrink and deform, with high and low temperature resistance, insufficient dimensional accuracy, and the plastic layer is poor in impact resistance, easy to break, and weakens the impact resistance of the protector, so it can not achieve good protection. effect. Summary of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art mentioned above, and to provide a steel pipe with reasonable structure, low shrinkage deformation, high and low temperature resistance, high dimensional accuracy, improved impact resistance, avoidance of falling off, and energy conservation. End thread protection.

The present invention is achieved by the following technical solution: A protective device for the end thread of a steel pipe, comprising a cylindrical rigid skeleton provided with a flange at one end, and being fitted with the rigid skeleton and having a recessed back cover a casing, the side periphery of the casing is provided with a thread for matching the thread provided at the end of the steel pipe, characterized in that the side periphery of the cylindrical rigid frame is provided with a rib; The housing is packaged using a staged injection molding process and a cylindrical rigid frame.

The side periphery of the rigid skeleton is an inner periphery;

The inner side of the rigid skeleton is equidistantly provided with at least four ribs;

The side periphery of the rigid skeleton is an outer periphery; The outer periphery of the rigid skeleton is equidistantly provided with at least four ribs;

The graded injection molding is at least two injection moldings.

The invention also provides a preparation method of the protection device for the end thread of the steel pipe, comprising the following steps:

1 preparing a cylindrical rigid skeleton;

2 rolling ribs around the periphery of the skeleton;

3 placing the cylindrical rigid skeleton in the mold of the injection molding machine, performing one-time injection molding on the inner side of the rigid skeleton, cooling and discharging;

4 The cylindrical rigid frame with one injection molding is then placed twice in the mold of the injection molding machine, and the injection molding with the inner rib shell is performed to cool and discharge the mold.

That is, the external thread protection device of the invention is prepared.

Another step of the preparation method of the present invention is:

1 preparing a cylindrical rigid skeleton;

2 placing the cylindrical rigid skeleton in the mold of the injection molding machine, performing one-shot molding on the outer side of the rigid skeleton, cooling, and discharging;

3 Then, a cylindrical rigid skeleton with one injection molding is placed twice in the mold of the injection molding machine, and the injection molding with the outer rib shell is performed to cool and discharge the mold.

That is, the internal thread protection device of the invention is prepared.

The beneficial effects of the invention are:

1. The protection device of the invention firstly performs the first injection molding on the outer surface or the inner surface of the cylindrical rigid skeleton, and then performs the secondary molding. The outer or inner injection molding shell once plays a good impact resistance. It is molded twice and the size is accurate. The product is not cracked at a low temperature of 46 degrees and has a high temperature of 66 degrees. It solves the problems of shrinkage deformation, high and low temperature resistance and insufficient dimensional accuracy in the prior art.

2. The manufacturing process of the thread of the plastic outer layer of the existing petroleum steel pipe thread protector is that after the plastic outer layer is injection molded, the thread is machined on the surface of the lathe, and the process is cumbersome. The invention is an injection mold equipped with a plastic outer layer with a thread. When the plastic outer layer is injection molded, the thread is injection molded, the repeatability is good, the thread size precision is high, the process is simple, and the surface smoothness of the product is good, no lathe processing The gap solves the problem of oil absorption.

3. According to the specific model and size of the pipe to be protected by the end, the invention can be made into a corresponding size model. When using, the matching protector can be screwed into the end of the pipe through the thread of the plastic outer layer of the protector. It is tightly coupled to the internal threads of the pipe to ensure that the pipe threads are not damaged.

4. The invention has wide application range and is applicable to petroleum steel pipes or other pipes of various diameters. Generally, the diameter range can be set from 23⁄4 inch to 20 inches. 5. The thread protection device of the invention can resist the strong impact force of different angles under special circumstances, realizes the rigidity and softness, and can closely match the external thread of the pipe wall of the pipe to be protected, so as to ensure that the pipe thread is not damaged. The structure is reasonable, the manufacturing process is simple, the cost is low, the use is convenient, the impact resistance is good, and the utility model can be repeatedly used for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a half cross-sectional structural view of a steel pipe rib protection device of the present invention;

2 is a half cross-sectional structural view showing another embodiment of the steel pipe rib protection device of the present invention; wherein the 1-cylindrical rigid skeleton 2-second molding layer 3-sub-molded casing 4-thread 5-rib

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings:

1 and 2 show a schematic view of the structure of the present invention with a half cross-sectional view. As can be seen from the figure, the protection device for the end thread of the steel pipe of the present invention comprises a cylindrical rigid frame 1 provided with a flange at one end, and the rigid frame 1 can be made of metal material or engineering plastic under the condition that the rigidity is satisfied. For example, stainless steel, nylon, aluminum profiles, etc., this embodiment is preferably made of a stainless steel material. The skeleton 1 and the casing 3 with a recessed back cover are put together, and the casing 3 can be any single type or a mixture of several types, such as polyethylene, polypropylene, polyvinyl chloride. The blend of polyethylene polypropylene, etc., is preferably prepared from a polyethylene material; the side periphery of the skeleton 1 is provided with a thread 4 for matching the end thread of the steel pipe. The side periphery of the skeleton 1 of the present invention refers to the inner side periphery or the outer side periphery. When the apparatus of the present invention is used as a steel pipe internal thread protecting device, the casing 3 is disposed outside the cylindrical rigid frame 1 (as shown in Fig. 2). Illustratively, when the device of the present invention is used as a steel pipe external thread protection device, the casing 3 is disposed on the inner side of the cylindrical rigid frame 1 (as shown in FIG. 1), thus facilitating the end portion of the steel pipe. The internal thread or the external thread is screwed to protect the end of the steel pipe; in order to make the rigid frame 1 and the casing 2 with the recessed back cover in close contact with each other to avoid deformation, the present invention overcomes the existing One injection molding shell in technology The technical defect of 3 is a step of forming the shell 3 once by forming the layer 2, and ribs 5 are provided on the side periphery of the rigid frame 1, and the ribs 5 may be on the inner side or the outer side of the frame 1. At least four strips are disposed at equal distances in the periphery, and the present embodiment is provided as ten strips. The first forming layer 2 can firmly bond the overmolded casing 3 and the rigid frame 1 together in a large area, and at the same time, The secondary forming layer 2 can also be filled into the ribs 5, and the ribs 5 serve as a left, right, upper and lower reinforcement, positioning function, thereby effectively preventing the shell and the skeleton from falling off each other; Secondary molding Layer 2 is a modified material, which can be made of any recycled plastic, which can greatly save energy, reduce cost and extend the service life of the protection device.

The preparation method of the invention comprises the protection device for preparing the external thread of the end portion of the steel pipe and the protection device for the internal thread of the end portion of the steel pipe. The method for preparing the outer thread of the steel pipe is: firstly, the cylindrical rigid skeleton 1 is prepared; then the rib 5 is rolled around the periphery of the skeleton 1; and the cylindrical rigid skeleton 1 is placed in the mold of the injection molding machine. Injecting the first molding layer 2 into the inner side of the rigid frame 1 for cooling; and then placing the cylindrical rigid skeleton 1 with the first molding 2 into the mold of the injection molding machine, and injecting the secondary rib with the inner rib The casing 3 is molded and cooled. That is, the outer rib protection device of the invention is prepared, as shown in FIG.

The preparation method of the internal thread protection device of the steel pipe end is: firstly, the cylindrical rigid skeleton 1 is prepared; the cylindrical rigid skeleton 1 is placed in the mold of the injection molding machine, and the first molding layer 2 is directly injected into the outer side of the rigid skeleton. Cooling; then placing the cylindrical rigid skeleton 1 with the first molding layer 2 into the mold of the injection molding machine, and injecting the overmolded housing 3 with the outer ribs for cooling; Internal rib protection, see Figure 2. The rigid frame of the internal thread protection device is disposed on the inner side of the housing, so that the ribs may or may not be rolled.

When the rigid skeleton 1 of the present invention is made of a stainless steel material, the rigid skeleton 1 can be prepared in two ways. The first type is made by cutting, rolling, welding, stretching, and derusting the steel sheet when the material is a steel sheet. When the material is a steel pipe, the steel pipe is cut, stretched, and rusted.

Claims

Rights request

1 . ······························································· The side periphery is provided with a thread, and the thread is matched with the thread provided at the end of the steel pipe, characterized in that the side periphery of the cylindrical rigid frame is provided with a rib; the casing is formed by a graded injection molding I Art. Carrying a rigid skeleton with a hidden column.

2. The protection device for a steel pipe end thread according to claim 1, wherein the side periphery of the skeleton is an inner periphery

The protection device for the end portion of the steel pipe according to claim 1 or 2, wherein the inner side of the skeleton is equidistantly provided with at least four ribs.

4. According to the claims '! The protective device for the end thread of the steel pipe, characterized in that the side periphery of the skeleton is an outer periphery.

5. The protective device for a steel pipe end thread according to claim 4, wherein the outer periphery of the skeleton is equidistantly provided with at least four ribs. Less injection molding ⁷ '

7. A method for preparing a protective bearing for the end of a steel pipe, characterized in that it comprises the following steps:

1 preparing a cylindrical rigid skeleton;

2 rolling ribs around the periphery of the skeleton;

3 The cylindrical rigid skeleton is placed in the mold of the injection molding machine, and the injection molding is performed on the inner side of the rigid skeleton to cool the fiber.

4 Then, the cylindrical rigid skeleton with one injection molding is placed twice in the mold of the injection molding machine, and the injection molding with the inner rib shell is performed, cooling, and discharging.

8. A method of manufacturing a protection device for a steel pipe end thread, characterized in that it comprises the following steps;

1 Preparation of cylindrical rigid skeleton ·:

2 placing the cylindrical rigid skeleton in the mold of the injection molding machine, performing one-shot molding on the side of the rigid skeleton, cooling, and discharging;

3 Then, the cylindrical rigid skeleton with the secondary injection molding is placed twice in the mold of the injection molding machine, and the injection molding with the outer rib 3⁄4 body is performed, and the mold is cooled and discharged.

9. According to the right to ask? Or a method for preparing a protective device for a steel pipe end thread according to 8, or characterized in that: The preparation material of the cylindrical rigid skeleton in the first step is a steel plate or a steel pipe

The method for preparing a protection device for a steel pipe end thread according to claim 7 or 8, wherein the primary injection molding is a modified material, and the overmolding is a polyethylene material.