Fire trench pipe acceptance specification according to what standard? According to the relevant national standards, grooved pipe fittings include two categories of products: a connection sealing role of the pipe has rigid joints, flexible joints, mechanical tee and grooved flange; There are elbow, tee, four-way, reducer, blind plate and so on. The grooved connecting pipe has three parts: sealing rubber ring, clamp and locking bolt. The rubber sealing ring located in the inner layer is arranged on the outer side of the connecting pipe, and tallies with the groove which is rolled in advance, the outer part of the rubber ring is buckled with a clamp, and the clamping ring is fastened with two bolts. Because the rubber seal ring and the clamps adopt the unique airtight structural design, the grooved connector has good airtightness, and with the increase of the fluid pressure in the tube, the sealing property is correspondingly enhanced.
Grooved pipe connection operation is very simple, without special professional skills, ordinary workers can operate after simple training. This is because the product has a large number of fine technical part of the factory into the finished product. A pipe connection takes only a few minutes, which simplifies the technical difficulty of the field operation, saves the working time, thus stabilizing the project quality and improving the work efficiency. This is also the general direction of the development of installation technology.
However, the traditional welding and flange connection not only need welding workers with the corresponding skills, but also time-consuming, difficult to operate, and there are welding dust pollution. Because of the difference of operation space and welding skill, welding quality and appearance are difficult to achieve satisfactory results, thus affecting the overall quality of the project.
In addition, because the grooved pipe fitting is a finished product, the operation space required at the scene is small, and the installation can really be realized by the wall and the angle, so the operation difficulty is greatly reduced, thus saving the occupied area and beautifying the effect of the installation of the pipeline.
Groove pipe connection, only to be connected to the external surface area of the pipe connected to a groove with a rolling trough machine squeeze out of a groove, without damage to the pipeline inner wall structure, this is the unique technical advantages of groove pipe connections. If conventional welding operations are used, many pipes whose inner walls have been treated with anticorrosive coatings will be damaged. Therefore, the specification stipulates that galvanized pipe, plastic lined steel pipe, steel plastic composite pipe shall not use welding and flange connection, otherwise the need for secondary treatment.
Using grooved pipe fittings connection technology, the site only needs cutting machine, groove rolling machine and bolt handle, construction organization is convenient. Welding and flange connection, it needs to be equipped with complex power cables, cutting tools, welding machine cylinder, etc., which brings complexity to the construction organization, and there are potential risks of leakage and fire. At the same time, welding slag produced by welding and gas cutting inevitably fall into the pipeline, which is easy to produce pipeline valves and even equipment blockage in use, and also pollute the water quality in the pipeline.
In addition, welding and flange connection inevitably need a long time of high-strength work, but also prone to production safety accidents.
The grooved pipe connection has a unique flexible feature, which makes the pipe have the ability to resist vibration, shrink and expansion. Compared with welding and flange connection, the stability of the pipeline system is increased, more suitable for temperature changes, thereby protecting the pipeline valve, but also reduce the pipeline stress damage to the structural components.
Because of the simple operation of the grooved pipe connection, the required operating space becomes smaller, which brings many convenient conditions for the future maintenance. When the pipeline needs to be repaired and replaced, just loosen the two pieces of clamps to arbitrarily replace, rotate, modify a section of pipeline. The utility model does not need to destroy the surrounding wall, and reduces the maintenance time and maintenance cost.
Installation requirements for grooved pipe fittings
1, in order to select the appropriate groove parts seal. Different media in the pipeline require different material seal ring, there are eight different materials in the market to apply to different media seal ring.
2, the pipeline groove is the key process of pipeline connection, but also determines the quality of the important link trench connection. The width and depth dimensions of the trench must meet the requirements. In the rolling groove, the end of the pipe should be flat, no burr, the port should be perpendicular to the pipe axis, so that the rolled groove and the pipe center axis can be vertical, while ensuring that the length of the groove to the end should be equal. If the pipe ovality and welding galvanized pipe wall thickness uneven, in the groove should be corrected as far as possible, otherwise the groove will produce uneven depth phenomenon, can not guarantee their tightness.
3, the seamless steel pipe groove connection, should be used regular manufacturers have zinc plating over the products, if used to buy a seamless steel tube to go out galvanizing way, Due to the oxidation corrosion of steel pipe for a long time, the quality of zinc plating can not be guaranteed, and the adhesion of the zinc coating is poor. It is easy to crack or even fall off in the rolling groove, thus affecting the sealing and service life. In order to achieve good sealing performance after pipeline installation, in addition to selecting grooved parts with good performance and ensuring no damage to the sealing ring, The flange and outside of the sealing ring should be coated with a layer of neutral lubricant to ensure that the lip of the seal ring and the pipeline seal ring fit more tightly.
4, the use of rigid joints, flexible joints in the grooved parts should be reasonable. The rigid joint is suitable for the end of the pipe in the low pressure pipeline which needs the rigid connection, such as the spray riser, the long distance linear pipeline, the valve, the equipment and so on. Required in the pipeline does not allow displacement, rotation and torsion of the occasion to use, in order to obtain good rigidity. The flexible joints are suitable for the connection of low and middle pressure pipelines. After installation, the pipes are allowed to shrink and deflect properly to compensate the slight displacement of the pipes. It is more suitable for pipe installation in uneven environment. It can also absorb noise, vibration and seismic stress. It is generally applied to the water pipe of the pump in the fire extinguishing system.
5, fire horizontal pipe if the distance is longer, the use of hangers, in order to suppress the pipeline channeling pipe, it is recommended that the middle of the local use of flexible joints to ensure that the axial channeling is not large, so as not to affect the bending of the lateral branch connected with it.
6, there is a certain temperature difference in the installation of fire pipeline, pipeline with a fixed bracket and anti-sway bracket, flexible joints and rigid joints can be used in combination, so that the pressure or temperature change produced by the axial force will not affect the bending of the lateral branch pipe.