CN214889628U

CN214889628U - Full-bore enhanced polyethylene elbow pipe fitting

Info

Publication number: CN214889628U
Application number: CN202120564356.3U
Authority: CN
Inventors: 冯建; 赵云龙; 康萏; 钱文来; 吴双; 金素洁; 曾钰龙; 冯能凯
Original assignee: Shanghai Nachuan Nuclear Energy New Material Technology Co ltd
Current assignee: Shanghai Nachuan Nuclear Energy New Material Technology Co ltd
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2021-11-26
Anticipated expiration: 2031-03-19

Abstract

The utility model relates to a full latus rectum enhancement mode polyethylene elbow pipe fitting, its concrete structure includes four bibliographic categories: a welding end (1); a transition zone (2); an engagement area (3); an elbow main body (4). The utility model has the advantages of reasonable design, have higher compressive property and excellent through-flow capacity, but wide application in power plant's cooling water system and large-scale reservoir water intaking system.

Description

Full-bore enhanced polyethylene elbow pipe fitting

Technical Field

The utility model relates to a plastic conduit field, concretely relates to full latus rectum enhancement mode polyethylene elbow pipe fitting.

Background

High Density Polyethylene (HDPE) pipelines have the advantages of corrosion resistance, excellent earthquake resistance, long service life, convenient construction and the like, and are widely applied to cooling water systems of power plants, water intake pipe network systems of large-scale reservoirs and the like in recent years. HDPE pipe fittings with the outer diameter smaller than 630mm in the current market are generally formed by injection molding of an injection molding machine in an integrated mode. However, in the application fields of power plants, large-scale reservoirs and the like, the caliber of polyethylene pipes and pipe fittings is generally larger than 800mm, and the requirement on pressure resistance grade is high. From the plasticizing capacity and the mold locking force level of the existing injection molding machine, the integral injection molding has the disadvantages of high technical difficulty and high equipment investment level. Resulting in very limited applications for large bore elbows, tees and other types of pipe.

Aiming at the problem, the international standard ISO 4427.3-2007 gives the design requirement of a multi-section welded shrimp-shaped elbow, as long as the cutting angle is less than 7.5 degrees, the reduction coefficient is not considered for the nominal pressure of the whole product, generally, a 90-degree elbow needs to be welded by 7 sections, the bending radius is too large, and the field installation is troublesome. In the American ASME boiler and pressure vessel design specification, the fact that a plurality of sections of welded elbows have a plurality of cutting angles is also considered that the integral pipe inevitably has a pressure reduction effect. For example, an injection molded pipe part of the SDR9 pressure class may have a nominal pressure of 2.0MPa as a design requirement, but for a multi-section welded SDR9 "shrimp" elbow, the bearing capacity may be reduced to 1.6 MPa. The ASTM F2206 standard provides a wall thickness enhancement requirement for a plurality of sections of welded pipe fittings, and for a pipeline system with certain pressure, if a plurality of sections of shrimp-shaped elbows are adopted, the wall thickness of the elbow pipe fittings needs to be increased by about 22 percent relative to the pipe fitting, so that the pressure bearing capacity of the whole pipeline system is not influenced.

However, on the premise of ensuring the hot-melt butt joint connection with the pipes with the same outer diameter and pressure grade, the pressure resistance of the pipeline system is improved by simply increasing the wall thickness of the pipe, but the inner diameter of the pipe is reduced, the through-flow cross section of the pipe is reduced, and the through-flow capacity of the system is influenced.

Disclosure of Invention

1. In order to solve the problem, the utility model provides a full latus rectum enhancement mode polyethylene elbow pipe fitting.

2. The technical scheme of the utility model is that:

a full-bore reinforced polyethylene elbow pipe fitting mainly comprises a welding end (1); a transition zone (2); an engagement area (3); an elbow main body (4). The elbow is characterized in that the welding end (1) is connected with the connecting area (3) into a whole through a chamfer of the transition area (2), the elbow main body (4) is formed by connecting three sections of pipe sections with the same size with the connecting area (3) through multi-angle hot melting butt joint, and the wall thickness of the elbow main body (4) is increased by about 25 percent compared with that of the pipe sections of the welding end (1).

The technical advantages of the utility model are that: (1) the wall thickness of the main body of the elbow pipe fitting is improved by 25%, and the bearing capacity of the system is enhanced; (2) the drift diameter of the elbow pipe fitting is consistent with that of the connected pipe, and the through-flow capacity of the pipeline system is improved; (3) the whole pipe fitting does not need a large-tonnage injection molding machine, only uses a multi-angle welding machine and an extruder, and has the advantages of low equipment investment, low production cost and good economic benefit.

Drawings

Fig. 1 is a plan view of the present invention.

Fig. 2 is a cross-sectional view of the present invention.

Detailed Description

1. The polyethylene raw material adopts a melt index of 0.16-0.18g/10min (5kg/190 ℃), and the density is 0.956-0.968g/cm 3.

2. After a neck ring mold, a core rod and a special sizing sleeve of the extrusion equipment are installed, the melt temperature is controlled at 180 ℃, the extrusion amount is 750kg/h, and a thick-wall pipe section with the outer diameter of 1000mm and the wall thickness of 160mm is extruded.

3. And then, selecting a pipe section with the length of 955mm, machining a welding end (1) with the length of 400mm and the outer diameter of 914mm by a lathe so as to be used for hot-melt butt joint with the pipe with the outer diameter of 914mm, wherein the design rule of the length of the pipe section is that the normal hot-melt butt joint and the possible electric smelting socket connection can be met.

4. And then, a chamfer of about R30-R50 is machined by a lathe to form a transition area (2), the chamfer is favorable for reducing stress concentration, the appearance of the elbow is attractive, and the misalignment of hot melt butt joint can be ensured to be within the standard requirement range.

5. The surface of the tube section was then slightly turned to control the outer diameter 986mm and the length 555mm of the tube section, forming the engagement zone (3).

6. And finally, machining 3 pipe sections with the outer length of 712mm, controlling the outer diameter of 986mm, and then machining a cutting angle at the tail end of each pipe section by using a multi-angle cutting saw, wherein the angle is controlled to be 11.25 degrees, so that a section of the 90-degree elbow main body (4) is formed.

7. And then welding each pipe section by using a multi-angle hot melting butt welding machine, wherein the temperature of a heating plate is 225 ℃, the interface pressure of a welding end surface is 0.45-0.6 MPa, the heat absorption time is 1020s, and the cooling time of each welding line is at least 50 min.

8. And after fully cooling, forming the full-bore reinforced elbow pipe fitting. The elbows with different outer diameters and center distances can be prefabricated and formed by the method through adjusting the sizes of the pipe sections.

9. The above technical solution is only one embodiment of the present invention, and for those skilled in the art, various modifications or variations can be easily made on the basis of the application method and principle disclosed in the present invention, and not limited to the structure described in the above specific embodiments of the present invention, so that the above described manner is only preferable, and not restrictive.

Claims

1. The utility model provides a full latus rectum enhancement mode polyethylene elbow pipe fitting which characterized by: mainly comprises four parts: a welding end (1); a transition zone (2); an engagement area (3); the elbow comprises an elbow main body (4), the welding end (1) is transited to the connection area (3) from a smooth chamfer of the transition area (2), and the connection area (3) is connected to the elbow main body (4) through hot-melting angle welding.

2. The full-bore reinforced polyethylene elbow pipe fitting as claimed in claim 1, wherein: the outer diameter of the welding end (1) is generally DN700, DN800 and DN900, and the wall thickness is generally larger than 80 mm.

3. The full-bore reinforced polyethylene elbow pipe fitting as claimed in claim 1, wherein: the transition region (2) is in smooth transition from an arc in the range of R30-R50.

4. The full-bore reinforced polyethylene elbow pipe fitting as claimed in claim 1, wherein: the elbow main body (4) is formed by three pipe sections with the same outer diameter and wall thickness through hot melting butt joint, and the cutting angle of the pipe sections is 11.25 degrees.