JPH04351395A - Protector of pipe end thread manufacture thereof - Google Patents

Abstract

PURPOSE:To give the protector of a pipe end thread, which is excellent in strength and toughness and is able to be incinerated. CONSTITUTION:The material of the cap-shaped protector 3 of the pipe end thread 2 of a pipe 1 is the sheet extended by pressure from row material composed of pulp fiber of 40% and polyolefin of 60%. This sheet is inserted into a metallic die after being heated upto 180-220 deg.C and is formed under pressure keeping its temperature at 180-220 deg.C. After being cooled, the molded part is drawn out from the metallic die. A sample has been cut off from this molded part, and its compression strength and impact strength have been measured, The results are 400-550kgf/cm<2> in compression strength and 30-50kgf-cm/cm<2> in Charpy impact value. As to combustion heat, it is only about 6800cal/g in this case, while it is 11000cal/g in the case of a polyolefin parts. So, it is possible to incinerate this protector by using a general incinerator.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread protector for pipes, oil country tubular goods, etc., which have threads at their ends, and a method for manufacturing the same.

0002

[Prior Art] When transporting a pipe with a thread at the end,
A member is required to protect the threaded portion from damage caused by blows during transportation. Although members made of iron or resin are generally used as the above-mentioned protective material, each has the following drawbacks.

(1) Made of iron: The threads at the end of the tube and the threads on the protective material are made of iron, and the threads are likely to seize when subjected to impact. (2) Made of resin: Since the strength is lower than that of iron, if the wall thickness is the same as iron, it will not be able to protect the screw threads from being bruised, so the wall thickness needs to be thicker, which increases the cost. In order to improve the above-mentioned drawbacks, a protective device made of a composite of iron and resin is disclosed in Japanese Utility Model Application Publication No. 53-33011. Such protective equipment leaves problems in its treatment after use. In other words, protective equipment is damaged during transportation, cannot be reused, and is mostly discarded, but because it is a composite of iron and resin, it cannot be incinerated or scrapped for reuse. Most of the waste is buried underground, contributing to environmental pollution.

0004

SUMMARY OF THE INVENTION An object of the present invention is to provide a tube end screw protector that solves the above problems. That is, the present invention provides a protective device that has an excellent pipe end screw protection function, is inexpensive, and can be incinerated, and a method for manufacturing the protective device.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, by constructing the protective member of the threaded portion of the pipe end with a material made of pulp fiber and reinforced synthetic resin, it has the strength and toughness as a protective device. It becomes possible to provide a screw protector that can be incinerated after use. That is, the present invention is a highly durable flammable cylindrical cap made of 10 to 49% by weight of pulp fibers and 51 to 90% by weight of reinforced synthetic resin, and having a thread that is threaded into a pipe end thread. This is an impact-resistant tube end screw protector.

[0006] Such protective gear uses a material consisting of 10 to 49% by weight of pulp fiber and 51 to 90% by weight of reinforced synthetic resin such as polyolefin, which is heated and placed in a mold. It can be manufactured by pouring the powder into the mold and press-molding it while heating. In this case, by mixing several weight percent of fibers having a fiber length of 20 to 40 mm, for example, one or two of inorganic fibers and metal fibers, to the above material, protective equipment with even better strength and toughness can be obtained. It becomes possible to manufacture

[0007] The above-mentioned material can also be processed into a non-woven fabric,
It can be produced by known methods such as dispersion mixing in water, paper making, dehydration, and drying.

[0008]

[Operation] Since the protective gear manufactured from the above material is composed of pulp fibers, it generates less heat than resin products. Therefore, it can be incinerated in a general incinerator, and the problem of disposal after use can be improved. In the present invention, the reinforced synthetic resin is a synthetic resin that exhibits strength and toughness when molded by blending with pulp fibers, and for example, polyolefin or the like may be used. A material with high strength but low toughness is unsuitable because it will break upon impact and the protector will fall off from the threaded portion of the tube end. Therefore, even if the strength is somewhat low, the threaded part will be protected to the end if it has toughness, that is, if the damage caused by impact does not reach destruction and the protector does not fall off from the threaded part of the pipe end. Figure 2 shows the relationship between strength and toughness depending on the blend of polyolefin and pulp fiber. The strength and toughness shown in FIG. 2 are expressed as a ratio of the strength and impact value required for protective equipment as 1. From this correlation, in order to satisfy the strength and impact value required for protective equipment, it is necessary to use 10 to 49% by weight of pulp fibers.

[0009] A sheet consisting of 10 to 49% by weight of pulp fiber and 51 to 90% by weight of synthetic resin such as olefin is
After being heated to ~220°C, it is charged into a mold and pressure-molded while heating, which promotes the entanglement of the blended synthetic resin and pulp fibers, resulting in the strength necessary for protective equipment.
Toughness value increases. By mixing several weight percent of inorganic fibers and/or metal fibers having a fiber length of 20 to 40 mm into the above-mentioned material, it becomes possible to manufacture protective gear with even better strength and toughness.

0010

[Example] Figures 1(a) and (b) show a tube 1 with a diameter of 76.3 mm.
A longitudinal section of a protector 3 that protects a screw 2 at the end of a tube is shown. The screw of the protector 3 is screwed into the screw 2 or the socket 5 at the end of the tube. Although the protective device 3 shown in FIG. 1(a) has a cylindrical shape with a bottom, the bottom plate 4 may be perforated. It is optional to provide grooves, protrusions, etc. on the outer surface or the circumferential outer surface of the bottom plate 4 for fitting or removing the pipe 1.

[0011] As a raw material, raw materials consisting of 40 parts of pulp fiber and 60 parts of polyolefin are mixed and pressed into a sheet.
After heating this sheet to 180 to 220°C, it is charged into a mold, and while heating to 180 to 220°C, a pressure of 100 is applied.
Pressure molding was performed by applying kgf/cm2 to 300 kgf/cm2. After cooling, the molded product was taken out from the mold. A sample was cut out from this molded product and the compressive strength and impact value were measured, and the compressive strength was 400 to 550 kgf/cm2,
The Charpy impact value was 30 to 50 kgf·cm/cm2. Further, when 5 parts of glass fiber having a fiber length of 20 to 40 mm was mixed into the above material, the compressive strength could be increased by 1.3 times, and the Charpy impact value could be increased by 1.2 times. In addition, the burned calories are 11,000 ca for polyolefin products.
l/g, whereas this product has 6,800 cal/g.
It was possible to incinerate it in a general incinerator.

0012

[Effects of the Invention] The protective equipment of the present invention has excellent strength and toughness, and can be disposed of by incineration. According to the present invention, it is possible to inexpensively manufacture a protector with an excellent function of protecting tube end screws.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a tube end screw protector.

FIG. 2 is a graph of the strength and toughness of a blend of pulp fiber and reinforced synthetic resin.

[Explanation of symbols]

1 tube
2 Threaded part 3 Protective equipment
4 Bottom plate 5
socket

Claims (3)

[Claims] 1. High impact resistance characterized by being a combustible cylindrical cap comprising 10 to 49% by weight of pulp fibers and 51 to 90% by weight of reinforced synthetic resin, and having a screw threaded into a pipe end thread. Genital tube end screw protector. 2. A tube end characterized in that a material consisting of 10-49% by weight of pulp fibers and 51-90% by weight of reinforced synthetic resin is heated, then charged into a mold, and pressure-molded while being heated. Method of manufacturing screw protectors. 3. The pipe end screw protector according to claim 2, wherein one or two selected from inorganic fibers and metal fibers having a fiber length of 20 to 40 mm are added to the material. manufacturing method.