The connection technology of grooved pipe fittings, also known as the clamp connection technology, has become the first technology for the connection of liquid and gas pipelines. Due to its advanced technology, it is quickly accepted by the market. The connection operation of grooved pipe fittings is very simple, no special professional skills are required, and ordinary workers can operate through simple training. This is because the product dissolves a large number of fine technical components into a finished product in an industrial manner. It only takes a few minutes to connect the pipe fittings, which greatly simplifies the technical difficulty of on-site operation, saves work time, stabilizes the project quality, and improves work efficiency.

installation methodes of grooved fittings
connection methodes of grooved fittings

presentation of grooved pipe fittings

Grooved fittings include two broad categories: the pipe fittings that play the role of connection and sealing include rigid joints, flexible joints, mechanical tee and groove flanges; the pipe fittings that play the role of connection and transition include elbows, tees, crosses, reducers, blind plates, etc.

The grooved connection pipe fittings that play the role of connection and sealing are mainly composed of three parts: sealing rubber ring, clamp and locking bolt. The rubber sealing ring located on the inner layer is placed on the outside of the connected pipe, and is in line with the pre-rolled groove, and then a clamp is fastened on the outside of the rubber ring, and then fastened with two bolts. Due to the unique sealable structure design of its rubber sealing ring and clamp, the grooved connection has good sealing performance, and with the increase of fluid pressure in the pipe, its sealing performance is correspondingly enhanced.

Advantages of grooved connection

easy installation

The connection operation of grooved pipe fittings is very simple, no special professional skills are required, and ordinary workers can operate it after simple training. This is because the product has incorporated a large number of fine technical parts into the finished product in a factory-like fashion. It only takes a few minutes to connect a pipe fitting, which simplifies the technical difficulty of on-site operation to the greatest extent and saves man-hours, thereby stabilizing the project quality and improving the work efficiency. This is also the general direction of the development of installation technology.

The traditional welding and flange connection pipeline connection method not only requires welding workers with corresponding skills, but also is time-consuming, difficult for workers to operate, and there is pollution from welding fume. Due to differences in operating space and welding skills, it is difficult to achieve satisfactory results in welding quality and appearance, thus affecting the overall quality of the project.

In addition, since the grooved pipe fittings are finished parts, the operation space required on site is small, and the installation can be realized against the wall and the corner, and the operation difficulty is greatly reduced, thereby saving the floor space and beautifying the effect of the pipe installation.

The original characteristics of the pipeline are not affected

For grooved pipe connection, only a groove is extruded on the outer surface of the pipe to be connected with a rolling groove machine without destroying the inner wall structure of the pipe, which is a unique technical advantage of grooved pipe connection. Many pipes with anti-corrosion coatings on their inner walls would be damaged if conventional welding operations were used. Therefore, the specification stipulates that galvanized pipes, plastic-lined steel pipes, steel-plastic composite pipes, etc. shall not be welded and flanged, otherwise secondary treatment is required.

Conducive to construction safety

Using grooved pipe connection technology, only cutting machine, rolling groove machine and wrench for tightening bolts are required on site, and the construction organization is convenient. The use of welding and flange connection requires complex power cables, cutting machines, welding machines, oxygen and acetylene gas cylinders, etc., which brings complexity to the construction organization, and there are hidden dangers of electric leakage and fire. . At the same time, the welding slag generated by welding and gas cutting will inevitably fall into the inside of the pipeline, and it is easy to cause pipeline valve parts and even equipment blockage during use, and also pollute the water quality in the pipeline. In addition, welding and flange connection inevitably require long-term high-intensity aerial work, and production safety accidents are also prone to occur.

Good system stability and easy maintenance

The grooved pipe connection method has unique flexibility characteristics, making the pipeline anti-vibration, anti-shrinkage and expansion. Compared with welding and flange connection, the stability of the pipeline system is increased, and it is more suitable for temperature changes, thereby protecting The pipeline valve parts are reduced, and the damage to the structural parts caused by the pipeline stress is also reduced. Due to the simple connection operation of grooved pipe fittings, the required operating space becomes smaller, which brings many convenient conditions for future maintenance. When the pipeline needs to be repaired and replaced, just loosen the two clamps to replace, rotate and modify a section of pipeline at will. There is no need to damage the surrounding walls, reducing maintenance time and maintenance costs.

Good economic benefits

Due to the simple operation of grooved pipe connection, labor-saving and time-saving, it has good economic benefits. Many articles have done economic analysis and believe that “with clamp connection, although the price of a single clamp is higher, the overall benefit of the entire pipe network installation is higher than that of flange connection”. In the comparison of the article, the flange connection is treated by secondary galvanizing (this is also required according to the specification).

Scope of application

As an advanced pipeline connection method, grooved pipe fittings can be either exposed or buried, including steel joints and flexible joints. Therefore, it has a broad scope of application.

According to the system: it can be used for fire water system, air conditioning cold and hot water system, water supply system, petrochemical pipeline system, thermal power and military pipeline system, sewage treatment pipeline system, etc.

According to the pipe material: it can be used to connect steel pipes, copper pipes, stainless steel pipes, plastic-lined steel pipes, ductile iron pipes, thick-walled plastic pipes, hoses and valves with steel pipe joints and flange joints.

installation steps

1. Technological process: installation preparation -> rolling groove -> opening, installation of mechanical tee and cross -> pipeline installation -> system pressure test – re-inspection of bolts.

2. Installation preparation: 2.1 Check the hole punching machine, rolling groove machine and pipe cutting machine to ensure safe use. 2.2 Preparation of materials and tools, including pipes, steel tapes, wrenches, vernier calipers, spirit levels, rulers, lubricants, wooden hammers, scaffolding, etc. 2.3 Install the support and hanger of the pipe to be installed according to the design requirements.

3. Roll groove: 3.1 Use a pipe cutting machine to cut the steel pipe to the required length, and check the cut section with a spirit level to ensure that the cut section is perpendicular to the central axis of the steel pipe. If the incision has burrs, it should be smoothed with a grinder. 3.2 Set up the steel pipe that needs to be grooved on the rolling groover and the tailstock of the rolling groove machine, and level it with a spirit level, so that the steel pipe is in a horizontal position. 3.3 Place the processed end section of the steel pipe close to the rolling groover, so that the central axis of the steel pipe is perpendicular to the surface of the roller. 3.4 Press down slowly. Jack, make the upper pressing wheel close to the steel pipe, start the rolling groove machine, and make the roller rotate for one week. At this time, pay attention to observe whether the section of the steel pipe is still close to the rolling groove machine. If not, adjust the pipe to the level. If it is tight, slowly press down the jack, so that the upper pressure wheel evenly rolls the steel pipe to the predetermined groove depth. 3.5 Stop the machine, check the depth and width of the groove with a vernier caliper, and after confirming that it meets the standard requirements, unload the jack and take out the steel pipe.

4. Open holes and install mechanical tee and cross: 4.1 Play the ink line on the steel pipe to determine the opening position of the branch pipe of the joint. 4.2 Fix the chain hole punching machine at the predetermined hole position of the steel pipe. 4.3 Start the motor, turn the hand wheel, slowly move the drill bit close to the steel pipe, and add lubricant to the drill bit to protect the drill bit, and complete the drilling on the steel pipe. 4.4 Stop the machine, shake the handwheel, open the chain, remove the hole punch, clean up the drilled metal blocks and the residue at the hole, and smooth the hole with a grinder. 4.5 Put the clamp on the steel pipe, note that the mechanical tee should be concentric with the hole, the gap between the rubber sealing ring and the hole is even, and the tightening bolts are in place. 4.6 If it is a mechanical cross, care must be taken to ensure that the holes on both sides of the steel pipe are concentric when opening, otherwise, when the installation is completed, it may cause the rubber ring to rupture and affect the water passage area.

5. Pipeline installation: in accordance with the principle of installing large-diameter, main pipe, and riser first, and then installing small-diameter and separate pipes. During the installation process, it must be installed continuously in sequence, and it is not allowed to skip installation or install in sections, so as to avoid the occurrence of section and section. Difficulty connecting between and affecting the overall performance of the pipeline. 5.1 Fix the steel pipe on the support and hanger, and cover the end of a steel pipe with a non-damaged rubber sealing ring. 5.2 Insert the other steel pipe that has been lubricated around the end into the rubber sealing ring, and turn the rubber sealing ring so that it is located in the middle of the interface. 5.3 Install the upper and lower clamps on the outside of the rubber sealing ring, and send the flanges of the clamps into the grooves, press the upper and lower clamp ears firmly, at the position of the clamp screw holes, tighten the bolts and evenly tighten the nuts alternately. During the process, hammer the clamp with a wooden hammer to ensure that the rubber sealing ring will not wrinkle, and the convex edge of the clamp should be clamped into the groove around the entire circumference. 5.4 Add support and hanger to the pipeline within 500mm of the rigid clamp joint.

6. After the system pressure test pipeline is installed, the system pressure test should be carried out. Before the pressure test of the system, it is necessary to comprehensively check whether the installation parts, fixing brackets, etc. are in place. The installed pipeline may sag. If the sag radian is large, a bracket can be added; if the radian is small, the radian will disappear naturally when the pressure in the pipeline increases.

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