Rigid Coupling vs Flexible Coupling: When to Use Each

 

There are two main types of grooved Coupling: Rigid Coupling and Flexible Coupling.

The characteristic of the Rigid Coupling is that the two adjacent pipe ports connected by it will not have the relative axial angle change and the displacement on the axis. This kind of pipe Coupling is mainly used in the riser pipe, empty rack pipe and other positions of the pipeline system.

The characteristic of the flexible pipe Coupling is that a certain amount of relative angle and deflection are allowed in the axial direction of the adjacent two pipe ends connected by it. The allowable angle variable is related to the size of the pipe mouth, so it is also called a flexible Coupling. This kind of pipe joint is mainly used for buried pipes or large-diameter pipes. This is because the buried pipes have different degrees of ground settlement in different sections, and the bottom surface of the trenches dug for laying the pipes is not necessarily flat, which will make The two adjacent sections of pipe are not on the same level, and the flexible pipe Coupling can completely solve this problem because it can have axial deflection. Due to the heavy weight of large-diameter pipes, there will be a certain relative angle between the two ends of the pipe and the middle. Therefore, large-diameter pipes usually use flexible pipe Coupling, and generally pipes with a diameter of ≥ DN250 are often used.

In engineering construction, due to insufficient technical disclosure and quality control, workers often make no distinction between rigid Coupling and flexible Coupling and use them at will, which brings hidden dangers to the reliable operation and normal maintenance of the entire pipeline system. Such as: domestic hot water system, the temperature difference between the operating temperature of the system and the installation of the pipeline can reach 60℃, the length of the steel pipe is 6m, and the thermal expansion stress will reach 1200kg/mm2. If the pipe is rigidly connected, it will cause deformation of the bracket and cause damage to the pipe system. Therefore, the Coupling pipe fittings should be distinguished and selected reasonably.

①     Domestic hot water pipelines, air-conditioning water pipelines, and open-air pipelines, in order to effectively compensate the pipeline displacement caused by thermal expansion and contraction, flexible Coupling must be used in the above three categories. If the displacement of the expansion section exceeds the total compensation amount of the flexible Coupling, the installation of metal expansion Coupling should also be considered.

②     Pipes with little temperature difference, such as indoor fire pipes, can use a large number of rigid Coupling. However, a certain number of flexible Coupling should be installed in the middle section of the long straight pipeline to compensate for a small amount of thermal expansion of the long straight pipeline section and ensure the safe operation of the entire pipeline system.

③      For elbows and broken-line pipes with temperature compensation function, flexible Coupling should be installed on the pipe sections where angular displacement occurs.

④     It is recommended to use flexible Coupling for pump room piping to reduce noise and weaken vibration transmission.

⑤     Buried pipelines should adopt flexible Coupling, which can effectively deal with the local deformation of the pipeline system caused by uneven settlement.

⑥     The connection of small arc-shaped pipes must use flexible pipe Coupling. It can be assembled according to the straight pipe first, and then the pipe can be turned to make it reach the predetermined angle. However, in any case, the angle of rotation shall not exceed the value specified in the specification of grooved pipe fittings.

   Jianzhi provides high-quality Rigid Coupling and Flexible Coupling, welcome to inquire.

 

What is a CE certification? How important is CE certification in the field of malleable pipe fittings?

 

What is a CE certification? How important is CE certification in the field of malleable pipe fittings?

 

 

 

In the last article, I introduced the FM certification in the United States in detail. As one of the most important product certifications in the world, FM certification is very important for enterprises. You can click the link below to see my introduction about FM certification.

 

Next, I will introduce the CE certification of the European Union. CE certification also has a high status in the world. It can be said that it is a standard pass for Chinese products to be exported to the European Union.

The malleable pipe fittings products of Jianzhi Group passed the CE certification of the European Union in 2019, which shows that the malleable steel pipe fittings of Jianzhi Group have reached the strict standards of the European Union, and also proves that the malleable pipe fittings products of Jianzhi Group have extremely high quality and safety and reliability.

Below, this article will take you to further understand what CE certification is, why CE certification is so important, how it differs from FM certification in the United States, and the use of CE certification in Jianzhi Group.

 

 

Table of contents

l  What is CE certification

l  Why CE certification is so important

l  How it differs from FM certification in the United States

l  The use of CE certification in Jianzhi Group

 

 

 

1.    What is CE certification？

CE certification is the abbreviation of French, English means "European Conformity", the actual CE is also the abbreviation of the phrase "European Community" in many countries of the European Community. Of course, you may also wish to regard CE as CONFORMITY WITH EUROPEAN (DEMAND) , the "main requirements" that constitute the core of the European directives, in the resolution of the European Community on May 7, 1985 (85/C136/01) "New Approaches to Technical Coordination and Standards", the need for the formulation and implementation of directives "Main requirements" have a specific meaning, that is, they are limited to the basic safety requirements that the product does not endanger the safety of humans, animals and goods, rather than general quality requirements. The harmonized directives only stipulate the main requirements, and the general directive requirements are the tasks of the standard. Products In line with the main requirements of relevant directives, the CE mark is a safety mark rather than a quality mark. In the 1940s, Western European countries felt that they must ensure their own safety between the United States and the Soviet Union, improve their international status, and accelerate economic development. United, so push the process of European integration. European integration can be divided into five levels: the establishment of a free trade area, customs union, unified market, economic and monetary union and political union. Therefore, CE certification is the product of European economic union.

 

CE certification logo

 

 

 

2.Why CE certification is so important

 

In the EU market, the "CE" mark is a compulsory certification mark. Whether it is a product produced by an enterprise within the EU or a product produced in other countries, if it wants to circulate freely in the EU market, the "CE" mark must be affixed to indicate that the product It complies with the basic requirements of the European Union's "New Approach to Technical Coordination and Standardization" directive. This is a mandatory requirement imposed by EU law on products. It indicates that the manufacturer of a particular product has checked the product and that the product meets the safety, health and environmental requirements of the European Union; it also indicates that the product complies with European regulations, therefore, the CE mark ensures the validity of the product sold throughout the European Economic Area.

In summary, if a product wants to legally enter the European market, it must obtain CE certification.

 

 

 

3.How it differs from FM certification in the United States

 

l  FM certification is more for industrial products, CE certification includes almost all commodities

l  FM is the largest risk insurer in the United States. It is an industrial property insurance company. It is not a US government certification body and is not a mandatory certification. CE certification is the official certification of the European Union and is mandatory.

l  For industrial products, FM certification is more stringent than CE certification. The former is more inclined to product quality certification, while the latter is more inclined to product safety certification

 

 

4. The use of CE certification in Jianzhi Group

 

The malleable steel products of Jianzhi Group have obtained the CE certification of the European Union, which shows that the malleable steel products of Jianzhi Group have met the strict standard requirements of EU countries for malleable steel pipe fittings.

 

Jianzhi Group can successfully pass various certifications including CE certificates because of the excellent quality of the malleable pipe fittings of Jianzhi Group. The excellent quality of malleable pipe fittings of Jianzhi Group is mainly reflected in:

 

 

a. The heaviest quality

Compared with the national standard products, Jianzhi products are the heaviest in quality, obviously heavier than the national standard products of the same specification from any domestic manufacturer.

b. The most beautiful appearance

Due to years of experience in molding and casting and leading technical advantages, the smoothness of the appearance of Jianzhi products is the best in China, and the galvanized surface is smooth and flat. Due to the fine and dense molding sand, there are no large sunken sand hole residue marks on the surface.

c. The most precise thread

As mentioned in the threading process above, the pipe thread standard for construction is the most stringent in the industry, and the length and precision of the pipe thread strictly follow the national standard. The installation is simple and trouble-free, and the sealing performance is good.

 

 

Well, that's all about CE certification. Welcome to this article series, I will introduce you to the relevant certifications of malleable pipe fittings or grooved pipe fittings. Of course, please click the link below to enter the youtube page of Jianzhi Group and watch more exciting videos.

 

https://www.youtube.com/channel/UC3meidzbmzv6n5neIX-symw

Types of pipe fittings and their uses

Pipe fittings are threaded together to connect pipes and help you configure your piping system, pipe fittings are threaded fittings with different shapes to form different pipe configurations. Pipe fittings include tees, elbows, Y-fittings, couplings and reducers. The role of pipe fittings in a water supply and drainage system is to connect multiple pipes of the same or different sizes in order to change direction, change size and branch joints. Various fittings play different roles depending on the shape or process requirements. They are made of different materials, commonly copper, iron, brass, PVC, etc. There are many different types of fittings used in piping systems, depending on their use and function.

Types of pipe fittings

Pipe fittings are as numerous and confusing as choosing the right screw or nail for a construction project, and there can be as many types as there are fittings, for example, including tees, elbows, Y-fittings, couplings and reducers. The materials vary and the specific purpose, although precise, can seem daunting.

Obviously, fittings are attached to the end of a pipe and can change direction, control flow and alter the diameter of the pipe. As an important part of your piping and plumbing system, we definitely recommend that you consult us for your requirements to save yourself time, money, materials and hassle.

Types of pipe fittings and their uses

Elbows: are used to change the angle or direction of a pipe. The most common are 90 degree and 45 degree turns. The scan of the fitting describes the speed of the transition or change of direction.

Street Elbows: fittings with a male thread on one end and a female thread on the other. These are common in galvanised steel and copper pipes. They are convenient because they do not require a nipple and work well in tight spaces.

T-shaped fittings: shaped like the letter T. Allows for branching.

Fittings: for connecting two straight tubes of the same diameter.

Reducers: for connecting pipes of different diameters. Makes a gradual change in diameter.

Bushing: Used to make the diameter of the fitting smaller. They differ from reducers in that they change diameter abruptly and take up very little space.

Live Fittings: Used to connect pipes that cannot be turned or when the equipment needs to be removed for maintenance or replacement.

Adapter fittings: used to replace the end of a non-threaded pipe with a male or female thread as required. Most commonly used for copper and plastic pipe work.

Caps: Used to close the end of dead-end pipes.

Plugs: Used to close the ends of fittings that are normally used for inspection or cleaning.

Fittings: Short pipes with threads at both ends.

Wyes: mainly used for internal access to the DWV (drain-waste-vent) system.

Valve: A device that controls the flow of liquid or gas through or out of a pipe. (compression valves, ball valves, sleeve cartridge valves, ceramic disc valves, etc.)

PVC fittings: available in many configurations, either glued (S) or threaded (T)

Brass fittings: use compression fittings. Common fittings are couplings, ELSs and tees.



We believe that after reading this article you will have a comprehensive understanding of tubing. Of course, this cannot be said to be comprehensive. If you would like to know more, you can open the following link to our website. The official website of Jianzhi Group presents a wealth of knowledge about pipe fittings. I am sure you can learn more here.

https://www.malleableiron-pipefitting.com/

Of course, you can also go to our YouTube page via the link below, where there are more great videos. You can get a better visual understanding of the fittings produced by the Jianzhi Group!

How To Connect Non-Threaded Galvanized Pipes?

Connecting unthreaded galvanized pipe together using couplings that form sealed joints. It is important to know the type of coupling used for galvanized non threaded pipe fittings and the installation procedure so that the pipe does not leak. Depending on the type of zinc and steel heating process, the galvanized pipe has a rough or smooth zinc coating. Most conventional galvanized pipe is rough, which can be a concern when trying to securely seal two pipes. Next, the galvanized pipe fittings supplier will share the following content with you.

Steps: Determine the diameter of the pipe, determine the smoothness of the pipe, check the orientation of the pipe, clean the galvanized pipe, insert the unthreaded galvanized pipe and tighten the bolts. More details read on!
Step 1

Use a tape measure to measure the outside diameter of each pipe. If the diameters match, choose a standard coupling. If the diameters are different, choose a stepped coupling.


Step 2

Look at the galvanized surface of the pipe to determine if the coating is rough or smooth. If the galvanized coating looks and feels textured, select a coupling manufactured to accommodate a rough surface pipe. Rough surface" couplings are required because they have tolerances for all types of uneven pipe surfaces, such as concrete and cast iron piping.


Step 3

Align the carpenter's level with the end of the unthreaded pipe to check that the end is square. If the ends are not flush, cut the ends with a hacksaw or chainsaw to make each pipe level. Use a metal sander to remove the rough edges of the tube ends.


Step 4

Wipe the pipe with a cloth and water-based degreaser to remove dirt and stains from the joint area. Place the ends of the tubes together. Center the joint on the pipe fitting and mark a pencil line on each pipe at each end of the fitting.


Step 5

Insert one end of the unthreaded galvanized pipe into the fitting. Align the coupling end with the drawn line on the pipe. Insert the second pipe into the coupling and place the coupling centered between the two drawn lines.


Step 6

Tighten the fastening bolts until the coupling just holds the galvanized pipe in place. Use the torque wrench set at the coupling mark torque requirement to tighten the bolts evenly until the wrench clicks.




After learning how to connect threadless galvanized pipes, the galvanized pipe fittings manufacturer will explain how to clean galvanized steel pipes.



How to clean galvanized steel pipes?

Galvanized steel pipes are used typically in plumbing applications where the metal is exposed constantly to moisture. To galvanize a steel pipe is to treat it with a special zinc-oxide coating to prevent oxidation and limit the damage to the pipe created by other corrosive elements. Cleaning galvanized pipe will extend the life of the zinc-oxide coating.
Step 1

Combine 1-gallon hot water, 1/4 cup dishwashing detergent, and 1 cup vinegar in a bucket.


Step 2

Dip the soft brush into the soap solution and scrub the pipe using small circular swirls.


Step 3

Rinse pipes with warm water and dry them.


Step 4

Apply metal polish using a lint-free rag in small circular rotations.


Step 5

Allow the metal polish to dry, then wipe clean.


Shop great prices on Galvanized Pipe Fittings available in various shapes. Here find fitting dimensions, specifications & all fittings sizes, contact us now! If you want to know about the wholesale galvanized pipe fittings price, welcome to contact us.

Some of the information above is from the JIANZHI news page.