How are qualified pipe fittings produced?

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How are qualified pipe fittings produced?

If the finished pipe fittings are viewed from the outside, it is difficult to distinguish between good and bad quality, which is only known during the use process. Engineering quality pays attention to safety first, and once an accident happens, it will cause irreparable losses.

So how are high-quality and qualified pipe fittings produced? Mainly consider the following links:

1. The raw materials of pipe fittings are base materials: in order to manufacture qualified pipe fittings, qualified raw materials must be selected. That is to say, the steel pipes, steel plates and billets used for manufacturing pipe fittings must be products that meet the requirements of the corresponding national standards after inspection. In practice, in order to reduce production costs, bad manufacturers use pipes or other raw materials from unknown sources, some purchase engineering surplus materials, some purchase defective pipes and test machine products processed by steel mills, some purchase retired oil and gas transmission steel pipes that have expired, and some use low-grade steel instead of high-demand steel, such as seamless steel pipes of GB/T 8162 instead of seamless steel pipes of GB/T8163, and even welded steel pipes with treated welds instead of seamless steel pipes. All these have brought endless hidden dangers to the purchaser.

2. Die for producing pipe fittings: The pressing, extruding and forging of dies are indispensable in the forming process of pipe fittings, so factories are required to inspect various manufacturing dies frequently to minimize the defects such as strain and scratch in the forming process of pipe fittings.

3. Heat treatment of pipe fittings: The main functions of heat treatment are to relieve stress, reduce hardness, refine grains and improve structure and performance. For stainless steel, it means austenitizing. Especially cold-formed pipe fittings, all must be heat treated. However, small coal furnaces are still used for heat treatment in very small factories, and the work depends entirely on workers’ experience, and the furnace temperature is unstable and uneven, which cannot guarantee the heat treatment effect. 4. NDE for pipe fittings: National and international standards have corresponding provisions on NDE for formed pipe fittings. For example, the cold extruded tee must be 100% magnetic particle inspected, and the weld must be 100% radiographic inspected. However, because some factories do not have the testing power, are lucky or overconfident, they omit the essential nondestructive testing link, and do not find the major surface or internal defects of the products, which foreshadows the hidden dangers.

5. Preparation of pipe ends: Most pipe fittings will be welded with pipes or other pipe fittings at the project site. This requires that the roundness, thickness and groove of the pipe end must be excellent, otherwise it will bring difficulties to the welding in the project site, and then affect the welding quality of the project. Some people think that the wall thickness of our pipe fittings is not worse than that required by customers, so there should be no problem. As everyone knows, too thick end thickness will also make welding impossible on site.

Decho is a professional supplier on pipe fittings , if you have any request , pls donot hesitate to contact us by email [email protected]

Principle and classification of check valves

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Principle and classification of check valves

 

Check valve The function of this type of valve is to allow the medium to flow in one direction only, and to prevent the opposite direction. Usually, this kind of valve works automatically, and the valve flap opens under the pressure of fluid flowing in one direction; When the fluid flows in the opposite direction, the fluid pressure and the self-overlapping disc of the disc act on the valve seat, thus cutting off the flow.

Structural classification

According to the structure, it can be divided into three types: lift check valve, swing check valve and butterfly check valve:

1. Lift check valves are divided into vertical and horizontal types.

2. Swing check valves are divided into three types: single-flap, double-flap and multi-flap.

3. Butterfly check valve is straight-through.

The above check valves can be divided into four types in connection form: threaded connection, flange connection, welding connection and butt clamp connection.

Material classification

1. Cast iron check valve

2. Brass check valve

3. Stainless steel check valve

4. Carbon steel check valve

5. Forged steel

check valve functional classification

1.DRVZ silent check valve Stainless steel check valve Stainless steel check valve

2.DRVG silent check valve

3.NRVR silent check valve

4.SFCV rubber flap check valve

5.DDCV double disc check valve

 

Decho is a professional supplier on check valves, if you have any request , pls donot hesitate to contact us by email [email protected]

What should we pay attention to when using three screw pump?

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What should we pay attention to when using three screw pump?

 

1. Selection of speed of three screw pump The flow rate of three screw pump has a linear relationship with rotation speed. Compared with the low-speed screw pump, the high-speed screw pump can increase the flow rate and lift, but the power is obviously increased. The high-speed screw pump accelerates the wear between rotor and stator, which will definitely lead to premature failure of the screw pump. Moreover, the stator and rotor of the high-speed screw pump are short in length and easy to wear, thus shortening the service life of the screw pump. The speed can be reduced by speed reducer or stepless speed regulation mechanism, so that the survey speed can be kept within a reasonable range below 300 revolutions per minute. Compared with the screw pump running at high speed, the service life can be prolonged several times.

2. The quality of screw pump There are many types of screw pumps in the market. Relatively speaking, the imported screw pumps are reasonable in design and excellent in material, but the price is high, some services are not in place, the price of accessories is high, and the ordering cycle is long, which may affect the normal operation of production. Most of the domestically produced products are imitations of imported products, and the quality of the products is mixed. When selecting domestically produced products and considering their cost performance, products with low speed, long lead, excellent transmission parts and long rated life are selected.

3. Ensure that sundries do not enter the pump body Solid impurities mixed in wet sludge will damage the rubber stator of screw pump, so it is very important to ensure that impurities do not enter the pump cavity. Many sewage plants have installed pulverizers in front of pumps, and some have installed grille devices or filters to prevent impurities from entering the screw pump. The grille should be cleaned in time to avoid blockage.

4. Maintain a constant outlet pressure Screw pump is a kind of positive displacement rotary pump. When the outlet end is blocked, the pressure will gradually increase to exceed the predetermined pressure value. At this time, the load of motor will increase sharply. The load of related parts of transmission machinery will also exceed the design value. In severe cases, the motor will burn out and the transmission parts will break. In order to avoid the damage of screw pump, a bypass overflow valve is usually installed at the outlet of three screw pump to stabilize the outlet pressure and keep the normal operation of the pump.

5. Avoid cutting materials Three screw pump will never be allowed to run under the condition of material breakage. Once it happens, the rubber stator will burn out due to the instantaneous high temperature caused by dry friction. Therefore, the crusher is in good condition and the grille is unblocked, which is one of the necessary conditions for the normal operation of screw pumps. For this reason, some screw pumps are also equipped with material breakage shutdown devices. When material breakage occurs, vacuum will be generated in the cavity due to its self-priming function, and the vacuum device will stop the screw pumps from running.

Decho is a professional supplier on screw pumps , if you have any request , pls donot hesitate to contact us by email [email protected] .

Horizontal stainless steel storage tank

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Characteristics of stainless steel storage tanks:

1. Stainless steel tank has strong corrosion resistance, which is not corroded by residual chlorine in outside air and water. Each spherical tank is subjected to strong pressure test and inspection before leaving the factory, and its service life can reach more than 100 years under normal pressure.

2. The stainless steel tank has good sealing performance; Sealed design _ prevents harmful substances and mosquitoes from invading the tank, and ensures that the water quality is not polluted by the outside world and breeds red worms.

3. The scientific water flow design makes the sediment at the bottom of the tank not turn up because of the water flow. _ Domestic water and fire water are naturally layered, and the turbidity of domestic water coming out of the tank is reduced by 48.5%; But the water pressure increased obviously. It is beneficial to improve the performance of domestic water and fire water facilities.

4. Stainless steel tanks do not need to be cleaned frequently; Precipitated substances in water can be discharged only by regularly opening the drain valve at the bottom of the tank. Scale can be simply prepared once every three years, which greatly reduces the cleaning cost and avoids human bacterial and viral pollution.

Application of stainless steel storage tank：

Stainless steel storage tanks are tanks made of stainless steel. Compared with ordinary rotomoulded storage tanks, stainless steel storage tanks can withstand high pressure and are widely used in many high-pressure occasions.

At the same time, stainless steel storage tanks have a remarkable feature: The tank has excellent sealing performance, which eliminates the invasion of harmful substances and mosquitoes in the air, and ensures that the liquid stored in the tank will not be polluted by the outside world and will not breed red worms. Therefore, stainless steel storage tanks are mostly used for storing and transporting food and medicines, and are widely used in brewing industry and dairy industry.

 

Decho is a professional supplier on storage tanks, if you have any request , pls donot hesitate to contact us by email [email protected]

What should we pay attention to in the application of wafer butterfly valve?

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Wafer butterfly valve is a widely used valve. According to valve materials and driving forms, wafer butterfly valve can adapt to many different industries.

Sealing materials for wafer butterfly valves can be roughly divided into two types: soft sealing type and hard sealing type. Soft seal butterfly valve has excellent performance, but it can not be used in high temperature and high pressure pipeline due to the limitation of sealing materials. The sealing material of hard sealing butterfly valve is metal, which can resist high temperature and pressure, but its sealing performance is not particularly good.

Introduction of main parts and materials of wafer butterfly valve:

1.Valve body: gray cast iron, nodular cast iron, cast steel, stainless steel, etc.

2.Butterfly plate: nodular cast iron, cast steel, stainless steel, etc.

3.Valve stem: usually stainless steel;

4.Seat: soft seal (EPDM, NBR, PTFE, etc. ), hard seal (cemented carbide).

The driving forms of wafer butterfly valves are: handle drive, turbine drive, pneumatic drive, electric drive and so on.

Compared with valves with other connection forms, wafer butterfly valves have shorter structure length and smaller size, and are suitable for installation in narrow space environment. So what should we pay attention to when installing wafer butterfly valve?

  1. Before installation, clean the sealing surface of the valve and the inside of the pipeline without dust and impurities.
  2. The wafer butterfly valve needs a special flange. During installation, the flange hole position must be aligned with the “ear” hole position of the valve, and the flange part and the valve sealing ring are tightly pressed together.
  3. After the valve is fixed in the pipeline, it is necessary to do several valve opening and closing tests to observe whether there is blockage during the opening and closing of the butterfly plate.
  4. When installing the electric or pneumatic actuator of butterfly valve, attention should be paid to the position of actuator and butterfly plate, which should be assembled from opening to closing, and installed on the pipeline after assembly and debugging.

Decho is a professional supplier of butterfly valves, if you need any for your project, pls contact us by e-mail [email protected]

Bearings prolong service life-sealing effect

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Bearings are the basis for operating machinery, covering fields ranging from mining, motors, machine tools to transportation, power generation, and robotics. Ensuring the longest possible service life is essential to prevent excessive wear and tear; this wear and tear can lead to system failures, often leading to expensive downtime for equipment rebuilds.

Engineers can use standard bearing life expectancy to calculate the likely life of the bearing supply. Known as L10 life (or also known as B90 or C90 life), this theorem explains that 90% of bearings will reach or exceed a specific number of revolutions when used in a specific working environment. However, this expectation is not guaranteed; in practical applications, bearing failures are actually more common and more complex, affecting the life expectancy of most systems.

Although many factors can maximize the life of a bearing, the most important consideration is proper sealing-recent studies have shown that most bearing failures are caused by contaminated bearing oil. By using the best quality seals, engineers can prevent or greatly reduce pollution, significantly extend bearing life, while improving equipment uptime and preventing system failures.

Two main sealing systems

In order to protect the bearing, the seal helps to reduce excessive temperatures by effectively retaining the lubricant, thereby reducing wear. Perhaps more importantly, the seal prevents foreign debris from entering the bearing, preventing damage, deteriorating bearing performance, and ultimately causing them to stop working altogether.

The two most common sealing arrangements are called radial lip or friction contact seals, and labyrinth or non-contact seals. Both sealing systems help protect the bearing and extend the service life. Depending on the application, different designs are different, which ultimately determines the level of protection provided by these seals.

Friction contact seal

Early friction contact seals were made to maintain consistent contact with the sealing surface; today’s models use special shapes and geometries to create hydrodynamic effects, and more effective designs to maintain maximum protection. This design enables the seal to reduce friction and wear by circulating lubricating oil from under the sealing lip to the bearing system, thereby forming an advanced process that improves life and efficiency.

There are many friction seal designs that provide excellent performance at a slightly higher cost, such as a surface seal with a spring element, which can provide automatic adjustment, or a seal with two collars, with a grease collector around it, which can automatically Add grease. In addition to these options, the next best cost-effective option includes regular or occasional lubrication and a collar that is updated from the bearing. The cheapest options include collars that are not updated, felt rings that are occasionally updated, and felt rings that are never updated.

Non-friction seal

Non-contact sealing continues to be popular. The most common type is the labyrinth seal, which is designed with complex passages to prevent contaminants from entering while retaining lubricant and liquid. Another option is a hybrid design, which includes centrifugal force, drainage design, and other retention and removal methods to provide the best sealing performance.

The most effective (and most expensive) labyrinth seal arrangement includes a multi-channel model with automatic or regular grease replenishment. The multi-channel labyrinth seal where the bearing is occasionally re-lubricated is the second best choice, followed by the simple-running Nilos ring and the long-gap seal. More economical models with a shorter service life include short gaps, Z shields, and open bearing non-contact seals.

Decho is a professional supplier of bearings. If you need any type, pls contact us by email [email protected]

E-type bearings: toughness and economy

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Bearings are used in almost every industry, but sometimes designers need rugged parts that work reliably in the harshest environments. E-type bearings are very suitable for these conditions and can roll smoothly even in the presence of debris, dirt, water, chemicals and high temperatures.

Another key benefit is that the rolling elements are tapered roller bearings, which can accommodate high radial and thrust loads.

In Decho, needle roller bearings have become our best-selling products because of their cost-effective design. The key lies in the housing: these components use strong steel, cast iron or other strong materials to protect the bearing and provide excellent performance throughout the life of the bearing.

Two main types of units

There are two main designs of E-type bearings: standard and split. The standard unit has a single, solid shaft-ready housing, while the separate unit consists of two separate housings, providing greater flexibility in difficult settings.

Standard E-mounting units-robust material construction makes these units the best choice for high-capacity applications, with special bearings that can adapt to temperatures up to 350°F.

All standard E-type bearings are pre-lubricated and fully assembled to withstand radial, thrust and impact loads. Advanced applications and industries such as mining, water treatment, mills and paper shredders require such powerful bearings.

Split housing E-type mounting units-the split structure of these units allows them to accommodate deviations of up to ±4°. It can be used for the expansion design of the super long linear axis to ensure the largest positive contact and excellent performance.

The split housing unit reduces downtime by inserting replacement parts, allowing quick and convenient maintenance, while keeping the housing base fixed and aligned. Can be used for steel, split housing units in the toughest industries where booming applications, such as forestry, marine, fans and blowers, and cement.

Decho is a professional supplier on needle bearings, if you need any , pls contact us by email [email protected]

Three types of harsh environments requiring special bearings

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Generally speaking, most bearings, cam followers and other rolling elements are made of AISI52100 material, which is a mixture of degassed low-alloy steel containing a large amount of chromium and carbon. AISI52100 material has high hardness grade and excellent wear resistance and deformability. These characteristics make AISI52100 material an ideal material for ball bearing and needle bearing applications. Bearings made of AISI52100 are used in a wide range of industries, from mining and material processing to entertainment and power generation.

However, standard AISI52100 bearings cannot withstand some harsh environments, so special materials are often needed to produce rolling parts. In these cases, AISI304, AISI440, AISI630, titanium, ceramic and grease-free bearings can be used.

When selecting the correct type of bearing material for your specific application, the following conditions should be kept in mind:

Corrosive environment

Many industries operate in well-known corrosive environments, including food processing, semiconductors, metal plating, medical equipment, and military markets.

In the food processing industry alone, high costs are required to repair corrosion-related damage every year. Food processing usually requires a lot of water, which is corrosive; high-acid foods, such as sauces, salad dressings and kimchi, are more corrosive. This environment can lead to rapid equipment degradation, costly maintenance downtime, and food contamination.

Equipment in the semiconductor and medical industries also undergo rigorous cleaning, decontamination and disinfection procedures, which usually involve the use of harsh corrosive chemicals. The metal plating process requires alkaline and acid treatments. The military has strict anti-corrosion requirements for equipment (including vehicles, weapons and other machinery) to help them withstand harsh environmental conditions.

For all these highly corrosive environments, standard AISI52100 bearings are unqualified; special corrosion-resistant bearings are required to ensure normal operation. In these cases, bearings made of titanium or AISI304, AISI440 or AISI630 stainless steel should be considered.

High temperature environment

The temperature in many industrial environments is at least 400 degrees Celsius (752 degrees Fahrenheit). For example, in the corrugated board manufacturing process, a series of rollers are used to curl the central groove and adhere the outer sheet to the groove. These rollers are heated to about 365 degrees Fahrenheit. To ensure normal operation, special high-temperature bearings are required. Metal processing also requires very high temperatures and corrosion resistance, because the pH value fluctuates during processing.

The ideal temperature-resistant bearing will be made of AISI304 or AISI630 stainless steel because these metals are resistant to both high temperature and corrosion. Grease-free bearings are another good choice because bearing lubrication often fails under high temperature conditions.

Electric environment

Electric current can cause incredible damage to metal parts. For the bearing, it will cause a series of problems, including the air passage in the bearing race, the pitting corrosion of the needle roller bearing and the decrease of lubrication performance. For example, various electric motors, electric traction motors in railway applications, and medical equipment such as magnetic resonance imagers all involve high-stress environments with large amounts of electrical activity.

Ceramic bearings, as well as ceramic insulated metal bearings, are ideal for high-charge applications. Ceramic materials, with a few rare exceptions, are very poor electrical conductors; although they can accept large voltages, they can dissipate this electrical energy very effectively. The passing current hardly causes degradation.

Decho is a professional supplier of ceramic bearings. If you need any , pls contact us by email [email protected]

What are the design considerations for food-grade bearings?

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Bearings are widely used in the food and beverage industry as components in various food processing and packaging machinery. Food-grade bearings must withstand extreme conditions in many applications. Therefore, the life and performance of bearings used in these applications are largely affected by the decisions of designers and engineers. Design considerations that may affect bearing durability in food-grade applications include material, lubrication type, and shielding options.

Bearings for food processing and packaging must withstand harsh operating conditions and the same harsh cleaning procedures to comply with strict hygiene standards and government regulations. Common conditions that bearings must endure include: contact with corrosive food and beverage ingredients, contact with cleaning chemicals, high-pressure washing, and high ambient humidity

Regulatory requirements for the food processing and packaging industry

Food manufacturers have been subject to production and processing regulations for decades, and these standards are still evolving. National and local governments have very strict regulations on the food processing and packaging industry.

The materials used in food packaging or production must be national and local regulations and requirements. This usually includes the bearings and lubricants used in the processing equipment.

The following factors must be considered when the production meets the requirements of food grade bearings:

Lubrication method

Like most bearings, lubrication plays a vital role in extending the life of food-grade bearings and improving their overall performance. Food processing and packaging equipment requires special lubricants that can withstand the harsh conditions generated during the cooking process and the frequent washing required to maintain hygienic conditions.

The choice of lubricant depends on the various conditions that the bearing will be subjected to, as well as any relevant regulatory requirements for the particular type of operation or product. Since lubrication may come into contact with food, the lubricant used must meet specific regulatory standards.

Proper lubrication depends entirely on the specific conditions of the application. Generally, lubricants should have good anti-corrosion and anti-wear properties. Lubricants used in high temperature applications must maintain oxidation stability at standard operating temperatures.
Materials

Not all metals are suitable for food processing and packaging. The materials used in the manufacture of food-grade bearings should have the highest purity to create durable and highly corrosion-resistant bearings. Metals such as stainless steel are widely used in food processing.

Although expensive, nitrogen-strengthened martensitic stainless steel bearings with extremely corrosive elements are often selected. The corrosion resistance of these bearings is five times that of standard stainless steel bearings.
seal

Bearings in food processing plants and packaging plants are constantly exposed to liquids and various types of debris and are often washed. Sealed or shielded bearings are essential to keep lubricant in the assembly while keeping unwanted debris and fluid out of the inside of the bearing assembly.

The seals and protective covers used must also comply with food industry regulations and guidelines for use with liquids, food and chemicals, so that they will not contaminate any products. Nitrile rubber and fluorine rubber are the most commonly used sealing materials for food-grade bearings, and they may also be wrapped in stainless steel or galvanized steel. The design and construction of the seal can significantly improve the function of the bearing in extreme environments.

Decho is a professional supplier on food-grade bearings. If you need any , pls contact us by email [email protected]

Four type of bearings for machine tool spindles

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In the machine tool industry, the spindle is a key component that uses high-speed rotation and pressure forming materials. With the advancement of modern machinery, the requirements for machining equipment are getting higher and higher, more precise and more durable. The bearing is a key component that guides and strengthens the movement of the main shaft. The use of high-quality bearings improves the working efficiency and reliability of the machine tool spindle, thereby increasing output and reducing mechanical wear.
The demand for bearings in the machine tool industry

With the advent of CNC technology, people expect machine tools to be more accurate, efficient, and reliable than ever before. In order to remain competitive, machining companies are investing in high-quality bearings to ensure the highest equipment performance. The overall purpose of the spindle bearing is to improve and simplify the movement of the spindle to ensure the best machine speed and accuracy. Bearings affect the speed, rotation, vibration, accuracy, and temperature of the machine tool, thereby changing the quality of the final product.

Bearings usually consist of one or a series of rings with balls or other rolling elements that streamline the movement of the main shaft in the desired direction. According to the equipment and the required movement, the bearing can be designed to facilitate the movement of the main shaft on the transverse and radial shafts. They must be able to withstand the load pressure, temperature and high speed of the machine tool spindle.

Bearings used in machine tool spindles are divided into four categories. Each bearing design has some characteristics that make it very useful in certain applications. It is very important to understand the working principle of each bearing, so you can choose the best bearing for your equipment.

Angular contact ball bearings

Angular contact ball bearings are the most common spindle bearings. They are rolling bearings, consisting of one or more rows of rolling balls between concentric grooved rings. They are useful for both radial and axial loads in one direction, and their axial load carrying capacity is determined by the angle of contact between the load and the bearing. The larger the angle, the higher the carrying capacity.

Radial or deep groove bearings

In industrial machinery, radial bearings are rolling bearings, which are mainly used to carry bearings on radial shafts. Like angular contact bearings, they consist of an inner ring and an outer ring with rolling balls between the inner ring and the outer ring; however, radial bearings can carry loads in both axial directions, making them more versatile than angular contact bearings .

Roller bearing

Roller bearings enhance movement by using rollers instead of balls. They are mainly used to support radial loads and axial loads parallel to the shaft in one direction. They are very useful in medium and high speed applications, which can reduce friction and increase equipment speed.

Thrust ball bearing

Thrust ball bearings are designed to support heavy, high-precision thrust loads, providing very precise axial support parallel to the drive shaft, but almost no radial support. The rolling elements can be balls, rollers or needles, depending on the application. They are particularly suitable for applications such as propeller engines, which support the free and easy movement of heavy objects parallel to the shaft.

Decho is a professional supplier on angular contact ball bearing, deep groove ball bearings, roller bearings and thrust ball bearings. If you any of them, pls feel free to contact us by email [email protected]