Press-fit coated carbon steel pipe for fire protection

Press-fit coated carbon steel pipe for fire protection

Press-fit (also called compression-type) pipes and fittings have been around for more than a century. From the original pure copper material, to stainless steel material, and now to carbon steel material, they are widely used for fluid transportation. Pipes are mainly used in non-potable water supply systems such as fire protection and heating. The materials are all made of high-quality carbon structural steel, and the surface of the pipes is galvanized and epoxy resin is used for anti-corrosion. The press-fit connection method has the advantages of light weight, good mechanical properties, long service life, convenient and quick installation, and material saving. After more than 60 years of development, it has been widely used. It is widely used in applications where the nominal size is not larger than DN100 and the nominal pressure is not larger than DN100. Non-potable hot and cold water, fire water supply, air conditioning water, gas, heating, energy storage industry and other fields with a temperature greater than 1.6MPa.

1. What is a crimp connection?

Press-fit connection is a mechanical connection method. It realizes the connection by pressing two parts. The U-shaped groove at the end of the press-fit pipe fitting is equipped with a special rubber sealing ring. During installation, insert the pipe into the socket pipe fitting until it is in position. At the step position, use a special clamping tool to squeeze the U-shaped groove and the clamping part on one side of the U-shaped groove at the same time. After being extruded, the rubber sealing ring shrinks radially and tightens to seal. The pipe fittings and pipes in the pressed part shrink and deform (form a hexagonal shape) at the same time to position and fix, thus effectively realizing the connection of the pipelines.

2. What is the principle of crimp connection?

The principle of the crimp connection is to use a special clamping tool to deform the clamping part of the pipe and fittings, clamp the two parts tightly, and achieve anti-rotation. The middle end is small and the two ends are large, thereby realizing the connection. It can withstand a certain load and vibration, and the clamping When pressed, leakage protection is achieved through the radial contraction and tightening of the rubber sealing ring to achieve a sealing effect.

3. What are the applications of press-fit connections?

Press-fit connections have the advantages of reliable connection, simple structure, and easy installation. They are widely used in pipelines such as non-potable water, fire water supply, drainage, air conditioning water, gas, heating, compressed air, and energy storage industries.

Advantages of press-fit coated carbon steel pipes and fittings

1. Cost savings

The wall thickness of traditional galvanized pipes (stranded wire, welded, etc.) is about 3 to 4 mm. The wall thickness of carbon steel pipes using wire lining requires an increase in the depth of the pipe thread, resulting in an increase in the pipe wall thickness and an increase in the cost of the pipe. Compared with crimped carbon steel pipes, it consumes more raw materials.

Press-fit coated carbon steel pipes and fittings are 1.5~2mm. The wall thickness of carbon steel pipes connected by press-fit connection does not need to increase the depth of the pipe thread, reducing the components of the pipe wall thickness. Compared with traditional galvanized pipes Reduced wall thickness and less raw material consumption reduce the product cost of the pipeline. Secondly, thin-walled pipes are lightweight and convenient for transportation during installation, which also reduces labor requirements, greatly reducing labor intensity and labor costs.

2. More corrosion resistant

The joints of traditional galvanized pipes are easily corroded because the twisted wire destroys the galvanized layer and is unprotected. They need to be repainted in 2-3 years. It adopts crimping type connection without threading. The galvanized layer at the joint of pipes and fittings is not damaged, which greatly improves the corrosion resistance of the joints of pipes and fittings. The coated pipe is pressed on the inner and outer galvanized layers, and then the inner and outer walls are passed through. The vacuum adsorption or electrostatic adsorption coating process forms a layer of corrosion-resistant EP coating on the entire surface. The neutral salt spray test can reach more than 1,000 hours, while the traditional ordinary galvanized pipe only has 96 hours; the life span is more than 30 years. Compared with traditional galvanized pipes, which have a service life of only about 15 years, they have better performance and cost, reducing various losses to the limit.

3. The process is time consuming

Compared with traditional galvanized pipes, crimped pipes are installed faster and save man-hours. During installation, the pipe can be installed without threading. Using automatic crimping tools, the crimping speed is faster than threaded connection. There is no need to brush lubricant, wrap raw material tape, expose thread anti-corrosion and other processes, which can save more than 50% of the total cost. installation time.

4. Construction

(1) Traditional galvanized pipe skein connection: The bulky skein equipment is inconvenient to be flexibly transferred with the progress of the project. As a result, all pipe interfaces need to be uniformly wired at fixed points and then transported to the pipe connection points, which is time-consuming and labor-intensive. The twisted wire surface is rough and is a non-threaded sealed pipe thread. The connection port needs to be filled with raw material tape and hemp silk. If the filling is not in place, leakage points will often occur. It requires professional and skilled workers and is difficult to operate; it has a high water leakage rate, pollutes the environment, and easily causes risks.

(2) Traditional galvanized pipe welding connection: The operation is very difficult due to space constraints and is labor-intensive. High-temperature open flames at construction sites are high potential fire hazards. It requires high skills of the installers, high construction costs, many auxiliary facilities and consumables, and high maintenance difficulty.

Press-fit connection: The construction is more convenient. It only takes 7 to 10 seconds to connect a joint. Convenient tools and intelligent proofreading; it is light and convenient to press and form in one time. The use of clamping tools requires simple training, quick start-up, labor-saving construction, relatively low skill requirements for construction workers, and safer construction.

5. Repair and maintenance

Traditional galvanized pipes: difficult/need to be repainted every 2 years or so and replaced every 12 years or so, high cost.
Press-fit connection: easy/one-time installation, lifetime maintenance-free, more reliable, fast and economical.

6. Quality and safety

Traditional galvanized pipe:

(1) Traditional carbon steel galvanized pipes used to be connected with threaded threads. The pipe accessories that were threaded off-site were already rusty before use due to the lack of electroplating protective layer. The surface of the pipes that were threaded on-site was galvanized. The corrosion resistance of galvanized pipes has been greatly reduced.

(2) The galvanized pipe is contaminated with oil stains, residual burrs, etc. during the threading process, which affects the safety of pipe connections.

Crimp coated carbon steel pipe:

(1) All pipe fittings are standardized in the factory, ensuring stable quality and supply. High-frequency welding technology is used for fully automatic welding. 100% of the welded pipe fittings have been inspected by eddy current testing, and the leakage test is completed automatically in a magnetic field. Secondly, the threaded joints, like most reducer joints, are integrally formed and then fully automatically welded. They are 100% airtight and inspected to ensure product quality control.
(2) The quality of press-fit coated carbon steel pipe connections mainly depends on the tools rather than the constructor, thereby reducing the risk of installation errors. Once the clamping jaws start crimping, the tool will lock and automatically complete the crimping, avoiding water leakage and air leakage caused by human installation factors, and improving the construction quality.
(3) Press-fit coated carbon steel installation does not require a fire source (as compared to welding) or other potentially hazardous tools.
(4) The press-fit connection has high strength and is resistant to vibration. The connection part is "locked" at one time, which avoids the possibility of loosening of the "live joint" (such as the effects of house vibration, water hammer vibration, pipeline resonance, earthquake), meets the requirements of embedded installation, and reduces the need for concealed laying of pipelines. The probability of water leakage is reduced, and it is a leakage-proof waterstop, not a plugging-type waterstop, which reduces the workload of repair and maintenance.

7. Environmental protection

Traditional galvanized pipes: The material wall thickness is thicker and the product is heavy. During the installation process of the pipe, paint will be used for anti-rust spraying. Subsequent maintenance requires repainting, which is not environmentally friendly.
Press-fit carbon steel pipe: Press-fit brushless paint, environmentally friendly plastic powder spraying, no need for raw material belts, no welding, light weight, energy saving, environmental protection and emission reduction, lightweight design of pipes and fittings, saving nearly 50 yuan compared with traditional galvanized steel pipes % of raw materials, in line with the national energy conservation and emission reduction development strategy and reducing carbon emissions.

8. Assembled products

Crimped carbon steel pipe: The product has the characteristics of high efficiency, energy saving, environmental protection and safety, special customization, smart production, intelligent assembly, efficiency improvement and labor saving, etc. In the application of the energy storage industry, it can not only ensure the safety of battery production lines, warehousing and substation power supplies and other new energy sectors. The safety and reliability of fire protection can also reduce the production costs and energy consumption of the energy storage industry.

Summarize

In short, press-fit connection is a common mechanical connection method, which has the advantages of reliable connection, simple structure, and convenient installation. Since the use of press-fit connection technology, developed regions and developing countries around the world have gradually begun to abandon the tradition ( Such as welding, twisting, etc.) pipe connection methods, accept this reliable, fast and economical pressure-fitting pipe connection. And it is popularly used on pipes made of various metal materials.