The plug valve, with its simple structure and excellent sealing performance, has a wide range of applications in industrial fields. Its plug design allows for quick and safe opening and closing, making it suitable for numerous operating conditions that require strong sealing, high corrosion resistance, or frequent operation.

1. Applications Requiring High Sealing Performance

The plug valve excels in applications that require high sealing performance due to its unique design. The plug inside the valve body fits tightly, and the sealing material between the plug surface and the valve seat further enhances the sealing effect, effectively preventing leakage of the media. Many plug valves use high-performance sealing materials, such as polytetrafluoroethylene (PTFE), which are resistant to corrosion, making them suitable for transporting high-pressure and highly corrosive media in industries like oil and gas and chemicals.

(1) High Pressure Sealing Requirements in the Oil and Gas Industry

In oil and gas pipelines, the transportation of high-pressure, high-temperature gases or liquids is common, and any leakage could result in serious safety incidents. The plug valve, with its ability to quickly close and provide effective sealing, is an ideal choice for preventing leaks and ensuring the safety of the transportation process.

(2) Transportation of Volatile or Toxic Media

The sealing capability of the plug valve also makes it suitable for transporting volatile or toxic liquids and gases. Especially in fine chemicals and petrochemical production, preventing the leakage of volatile chemicals is a core aspect of safety. The sealing structure of the plug valve is perfectly suited to meet this requirement.

2. Frequent Opening and Closing Operations

The plug valve only requires a 90-degree rotation to open or close, making the operation simple and fast, while reducing mechanical wear. This makes the plug valve suitable for applications with frequent on/off cycles. In chemical plant production processes, valves are often required to open and close frequently to regulate fluid flow. Compared to other valves, the plug valve's opening and closing mechanism is more stable, which helps to extend its service life.

(1) Impact of Frequent Operation on Equipment

In environments where frequent operation is required, improper handling can lead to increased valve wear and a higher probability of leakage. Due to its simple structure and fewer components, the plug valve is less affected by frequent operations, offering significant economic benefits in this regard.

3. Applications with High Corrosion Resistance Requirements

Plug valves are typically made from corrosion-resistant materials, and their interiors are often lined with corrosion-resistant materials such as PTFE or reinforced plastics, allowing them to maintain long-term operation when handling acidic, alkaline, or corrosive solutions. Plug valves are particularly well-suited for the transportation of highly corrosive liquids.

(1) Transporting Corrosive Media in the Chemical Industry

In the chemical industry, the media being transported often have strong corrosive properties. The design of plug valves ensures that they do not fail quickly when in contact with corrosive liquids, effectively reducing the frequency of equipment replacement and saving on maintenance costs.

4. Emergency Systems Requiring Quick Shutoff

The quick open/close design of the plug valve allows it to rapidly shut off the fluid passage in emergency situations, making it an ideal choice for preventing accidents and ensuring the safety of operators. For example, in emergency shutdown systems for natural gas pipelines and chemical plants, the plug valve can achieve a complete closure in an instant, preventing the leakage of hazardous substances and ensuring safety.

(1) Safety Requirements in the Natural Gas and Petrochemical Industries

In the natural gas and petrochemical industries, where high-temperature and high-pressure environments are common, safety is of utmost importance. The plug valve is not only easy to operate but also capable of quickly shutting off in emergencies, thereby protecting the overall safety of the system and reducing potential safety risks.

5. Medium and Low Pressure Fluid Transportation Systems

In medium and low pressure fluid transportation systems, the plug valve is an economical and practical choice. Its simple design reduces installation and maintenance complexity, and in situations where high-precision flow control is not required, the cost-effectiveness of the plug valve stands out. It is commonly found in systems such as water treatment, municipal water supply, and general industrial pipelines.

(1) Municipal Water Supply and General Industrial Applications

In municipal water supply systems, plug valves are widely used for flow control. Compared to more complex control valves, the plug valve features a simple structure and easy installation, making it suitable for fluid control applications that do not require high precision, while also being easier to maintain.

Gate valves are a popular choice in many industries for specific types of applications. Here’s why they are commonly used:

1. Full Flow or Isolation

Gate valves are ideal for situations where a full, unobstructed flow or complete shutoff is required. When fully opened, the gate valve allows fluid to pass through with minimal restriction, which helps to reduce pressure loss. This makes them particularly useful in systems where flow efficiency is critical, such as pipeline systems in oil, gas, and water distribution.

2. Low Pressure Drop

Because the gate in the valve fully retracts, there is little interference with the fluid flow when the valve is open. This results in low pressure drop, which is essential in applications where maintaining high flow efficiency is important, such as in petroleum refining or water treatment plants.

3. Versatility Across Applications

Gate valves can handle a wide range of fluids, including liquids, gases, and even slurry or other more viscous materials. They are also used in a variety of pressure and temperature conditions, making them highly versatile. This versatility is why they are found in industries such as chemical processing, mining, and power generation.

4. Bi-Directional Sealing

Gate valves can provide a tight seal in both directions, meaning they can effectively stop flow from either side of the valve. This feature makes them suitable for applications that require flow isolation from both ends, ensuring safety and operational control, especially in critical systems like offshore platforms and high-pressure pipelines.

5. Durability in Large-Scale Systems

Gate valves are particularly durable when used in large-diameter piping systems. Due to their robust design, they can handle the stresses of large-scale industrial applications, such as those found in hydropower or municipal water systems. Their ability to withstand high-pressure and high-temperature conditions adds to their durability and reliability.

6. Emergency Shutoff

Gate valves are often used as emergency shutoff valves because of their ability to completely block flow when needed. In situations where quick and reliable isolation is required, such as firefighting systems or hazardous material pipelines, gate valves offer peace of mind.

Ball valves are widely used in various industrial sectors due to their simple structure, excellent sealing performance, and ease of operation. However, during long-term use, ball valves may develop leaks. Leaks not only lead to the waste of media but can also disrupt the normal operation of the system and even pose safety risks.

Common Reasons

1. Aging or Damage of Sealing Materials

The sealing performance of a ball valve primarily relies on the tight fit between the valve seat and the ball. These sealing components are typically made from materials such as rubber or polytetrafluoroethylene (PTFE). Over long-term use, the sealing materials may experience aging, deformation, or damage due to medium corrosion, high-temperature and high-pressure environments, or friction, leading to leaks. This issue is particularly common in applications involving high temperatures and highly corrosive media.

2. Wear of the Ball or Seat

The core components of a ball valve are the ball and the seat, which continuously contact and rub against each other during opening and closing. If the medium contains solid particles, or if the ball valve operates for an extended period in high-pressure, high-flow environments, wear can occur on the surfaces of the ball and seat. Worn surfaces struggle to form a tight seal with the sealing components, leading to inadequate sealing and resulting leaks.

3. Seal Failure of the Stem

The operation of a ball valve is facilitated by the stem, which connects to the valve body through the packing gland, providing a sealing function. Due to frequent operation, aging of the packing, or improper installation, the packing gland may experience seal failure, allowing the medium to leak along the stem. This type of leak is classified as external leakage, which can lead to environmental pollution and energy waste.

4. Improper Installation

If a ball valve is not correctly installed or tightened at the flange or threaded connections, gaps may occur, leading to leaks. Additionally, if factors such as thermal expansion and vibration of the pipeline are not considered during installation, the ball valve may experience stress during operation, resulting in leakage at the interface between the valve body and the pipeline.

5. Medium Factors

Certain special media, such as high-temperature, high-pressure fluids, highly corrosive substances, or fluids containing suspended particles, can accelerate the wear and corrosion of ball valves, leading to leaks. For example, acidic media can hasten the corrosion of metal components, while particulate matter may cause wear on the seat and ball, both of which can diminish the sealing performance of the ball valve, ultimately resulting in leakage issues.

How to Prevent and Handle

1. Choose Appropriate Sealing Materials

Selecting the right sealing materials for different operating conditions is crucial. For example, in high-temperature environments, high-temperature resistant sealing materials should be chosen, while chemical-resistant seals are necessary for highly corrosive media. Regular inspection and replacement of seals can also effectively prevent leaks caused by aging or wear.

2. Regular Maintenance and Care

Routine maintenance and regular servicing of ball valves help extend their lifespan and reduce the risk of leaks. The wear of the ball and seat should be regularly checked, and impurities and particles in the medium should be promptly removed to prevent further wear. Additionally, the packing should be inspected to ensure good sealing, and aging packing should be replaced in a timely manner.

3. Proper Installation and Operation

Installation should strictly adhere to the technical specifications of the ball valve, ensuring that flange or threaded connections are tight to avoid leaks caused by thermal expansion, vibration, or stress. Additionally, during operation, frequent opening and closing should be avoided, especially under high-pressure conditions, to reduce wear on the valve.

4. Special Treatment for Media

For applications involving fluids with suspended particles or strong corrosive properties, it is advisable to install a filter upstream of the ball valve to reduce solid particle damage to the valve. Additionally, choosing ball valves made from corrosion-resistant materials can effectively slow down the corrosion process and lower the risk of leakage.

A gate valve is considered better than a ball valve in certain applications due to its design and functional advantages in specific conditions. Here are some key reasons why a gate valve might be preferred over a ball valve:

1. Flow Control

Gate Valve: Designed for full, unobstructed flow when fully open, allowing fluids to pass with minimal resistance. It is ideal for on-off control but not as suitable for throttling or flow regulation, as partial opening can cause vibration and damage to the sealing surfaces.

Ball Valve: While it offers full flow similar to a gate valve when open, it is not generally used for precise flow control either. However, it closes and opens faster than a gate valve, which may not always be ideal for systems that require gradual control of flow.

2. Size Availability

Gate Valve: Typically better for larger diameter applications, as they are available in larger sizes, making them suitable for large pipelines in industries like water treatment, oil, and gas.

Ball Valve: More commonly used in smaller pipe sizes but can also be found in larger sizes. However, large ball valves can become bulky and expensive compared to gate valves.

3. Pressure Drop

Gate Valve: When fully open, the gate valve provides a straight flow path with minimal pressure drop, which is beneficial in applications where maintaining fluid pressure is critical.

Ball Valve: Even though a ball valve offers low resistance to flow when fully open, the pressure drop might be slightly higher due to the internal mechanism of the ball and seat, especially in smaller sizes.

4. Cost Efficiency in Larger Systems

Gate Valve: More economical for large-diameter and high-pressure systems, making it a preferred choice in large-scale applications like water supply systems or oil pipelines.

Ball Valve: Generally more expensive for large diameters, as the ball itself and its seat must be designed to handle high pressures without deforming.

5. Operational Effort

Gate Valve: Requires more time and effort to open and close fully, as the gate needs to travel vertically through the fluid. This can be a disadvantage in situations where fast operation is needed but may be an advantage in preventing water hammer.

Ball Valve: Opens and closes quickly with a 90-degree turn, which is more convenient for applications requiring rapid shutoff. However, this quick action may cause issues like water hammer in some fluid systems.

6. Maintenance and Wear

Gate Valve: Due to its simple design, gate valves are easier to maintain and have a longer lifespan in systems where they are rarely operated. The seating surfaces experience less wear when the valve is either fully open or fully closed.

Ball Valve: The sealing surfaces in ball valves are more prone to wear, especially in high-pressure or abrasive flow conditions. Maintenance can be more complex, particularly with large valves.

7. Suitability for Dirty Fluids

Gate Valve: More suitable for handling fluids containing solids or slurries, as the gate can cut through debris or sediments. It is less prone to clogging in such environments.

Ball Valve: Not ideal for dirty or viscous fluids, as the tight tolerances between the ball and seat can trap particles, leading to damage or failure of the valve over time.

What is the difference between a forged steel ball valve and a cast steel ball valve? The difference mainly lies in the processing technology and processing method of steel:

A cast steel ball valves is a kind of ball valve that is formed by pouring liquids into a mold and then allowing them to solidify. Alloy steel is the most common casting material. Cast steel is divided into cast carbon steel, cast low alloy steel and cast special steel. Cast steel refers to a steel casting produced by a casting method. Cast steel is mainly used to make parts that are complex in shape, difficult to forge or cut, and require high strength and plasticity.

Forged steel ball valves are various ball valves with forged steel and forged pieces produced by forging process. Forged steel ball valves are stronger than cast steel ball valves and canbear large impact forces. Their plasticity, toughness and other mechanical properties are also higher than that of castings, so for some important machine parts, forged steel parts should be used.

Casting is liquid molding, while forging is a plastic deformation process. With improved internal structure, good mechanical properties and even grain texture, the forged work-piece is the perfect choice for important heavy-duty parts. The castingmay cause structural segregation, structural defects, but of course, casting has its own pros. The forming of complex work-pieces is not easy to be done by forging, in this case, casting process is more favorable.

Dervos is a leading industrial valve maker and trader in China, specializing in the production of ball valves.In addition to those incommon conditions, we also produce other special valves, OEM products and so on.To learn more about our industry-leading products, contact us today.

In industrial fluid control systems, ball valves are one of the most widely used valve types due to their compact design, rapid opening and closing, and excellent sealing performance. However, during the selection process, many engineers and users often have a common question: Do ball valves affect water flow? This article will explore the actual impact of ball valves on water flow from the perspectives of flow characteristics and pressure drop, and provide practical suggestions.

1. Basic Structure and Flow Capacity of Ball Valves

A ball valve is a valve that controls the flow of fluid by rotating a ball with a hole through it. When the hole aligns with the pipe's axis, water can flow freely with minimal resistance. This design is the core of the ball valve's "low flow resistance" characteristic. Based on the size of the hole, ball valves are typically divided into: - Full Port Ball Valve: The bore diameter is equal to the pipe diameter, resulting in very little pressure drop and having almost no impact on water flow velocity. It is suitable for systems with high flow requirements. - Reduced Port Ball Valve: The bore is slightly smaller than the pipe diameter, causing a certain pressure drop. However, it is relatively low-cost and suitable for situations with space constraints or moderate flow requirements.

 

2. Analysis of Ball Valve’s Impact on Water Flow

(1) Pressure Drop Generation

Although ball valves are designed to minimize flow resistance, in practical use, they still cause a slight pressure drop due to their structure and operating conditions (Pressure Drop). This effect is amplified when there are multiple elbows, valves, or high-viscosity fluids in the pipeline system. 

In reduced port ball valves, the fluid undergoes contraction and expansion when passing through a smaller channel, creating localized turbulence that results in a higher pressure drop. While this pressure drop has minimal impact on low-pressure water systems, it may require additional attention in high-precision control systems.  

 

(2) Flow Control Capability

Ball valves are not designed for precise flow regulation (unless it is a specially designed control ball valve like a V-port ball valve). The opening and closing characteristics of a ball valve are "quick-opening," meaning the relationship between valve opening and flow rate is non-linear. As a result, ball valves are better suited as on/off valves for fully open or fully closed applications, rather than for fine flow control.

 

3. How to Minimize the Impact of Ball Valves on Water Flow?

(1) Choose the Right Size and Port Type: If strict flow rate requirements are in place, it is recommended to choose full port ball valves. 

(2) Pay Attention to Installation Direction and Valve Position: Ensure that the valve is installed coaxially with the pipeline to avoid misalignment that could cause fluid disturbance. 

(3) Avoid Excessive Accessories Before and After the Ball Valve: Avoid excessive fittings such as elbows and filters near the valve to reduce accumulated pressure drop. 

(4) Regular Maintenance: Dirt or sediment buildup inside the valve can also affect flow, especially when dealing with unfiltered water. Regular maintenance and cleaning are essential to ensure optimal performance.

 

FAQ

Q1: What is the difference in water flow between a full port ball valve and a reduced port ball valve?

A full port ball valve has almost no impact on flow, while a reduced port ball valve may cause a 5%-15% reduction in flow, depending on the pipe diameter and pressure.

 

Q2: Is a ball valve suitable for regulating water flow?

Standard ball valves are not ideal for frequent flow regulation. It is recommended to use specialized models like V-ball valves for control applications.

 

Q3: Will using a ball valve cause a drop in water pressure?

In systems with low flow or proper configuration, the pressure drop is negligible. However, in complex piping systems, localized pressure drops should be evaluated.

 

Q4: Can a ball valve be used in residential water pipes?

Yes, it can, especially for main water lines or hot water systems, due to its excellent sealing performance and ease of operation.

The Heating Jacket Gate Valve is widely used in industries such as petrochemical, chemical, and pharmaceutical. Its primary function is to maintain the temperature of the valve and its internal fluid by circulating a heating medium within the jacket, preventing the fluid from solidifying or freezing due to temperature drop.

1. Advantages of the Heating Jacket Gate Valve

(1) Maintaining Fluid Temperature

The heating jacket gate valve maintains the temperature of the valve body and internal fluid through the heating medium circulating within the jacket (such as steam, hot oil, etc.), preventing the medium from solidifying or freezing due to temperature drop. This is particularly important for high-viscosity, crystallizable, or solidifying media.

(2) Preventing Pipeline Blockage

In low-temperature environments, certain fluids are prone to crystallizing or solidifying within the pipeline and valve, leading to blockages. The heating jacket gate valve effectively prevents this issue by heating the jacket, ensuring smooth operation of the pipeline system.

(3) Enhancing Process Efficiency

By maintaining the fluid's flowability, the heating jacket gate valve can significantly improve process efficiency, reducing downtime and production losses. This is especially beneficial in continuous production processes, offering notable economic advantages.

(4) Extending Equipment Lifespan

The design of the heating jacket gate valve reduces equipment wear and maintenance frequency caused by low temperatures, thereby extending the lifespan of the valve and associated equipment. This also helps lower maintenance costs.

(5) Wide Range of Applications

Heating jacket gate valves are suitable for various industries, including petrochemical, pharmaceutical, and food processing. They are capable of meeting the demands of various complex operating conditions and offer strong adaptability.

2. Limitations of the Heating Jacket Gate Valve

(1) Higher Costs

Due to the complex structure of heating jacket gate valves, their manufacturing costs are relatively high. Additionally, the need for heating media and related equipment results in higher initial investment and operating costs compared to standard valves.

(2) Strict Installation Requirements

The installation of heating jacket gate valves requires careful consideration of the heating medium's piping connections and insulation measures. The process is relatively complex and demands higher technical skills from the installation personnel.

(3) Complex Maintenance

Maintaining a heating jacket gate valve involves not only the upkeep of the valve itself but also the care of the heating jacket and the heating medium. This adds complexity to maintenance tasks and requires specialized technical support.

(4) Higher Energy Consumption

A heating jacket gate valve requires a continuous supply of heating medium, resulting in higher energy consumption. In situations where energy costs are high, using a heating jacket gate valve may increase operating expenses.

(5) Application Limitations

Although heating jacket gate valves are suitable for various industries, their primary application is in processes that require maintaining the temperature of fluids. In situations where heating or insulation is not needed, using a heating jacket gate valve may not be cost-effective.

Installation requirements for cryogenic valves

Due to the special structure of cryogenic valves, the installation of cryogenic valves also has special requirements. Because of the long-neck bonnet of the cryogenic valve, cryogenic gate valves must be installed vertically upward, with the stem direction within a 45-degree angle. And it should also be avoided as much as possible to install the valve on vertical pipelines. Otherwise, the low-temperature medium may fill the extended part of the valve cover, causing the valve packing to fail. In addition, it will transfer the cold to the valve handle, injuring the operator.

For cryogenic ball valves with pressure relief devices, extra attention should be paid to the requirements of the valve pressure relief direction during installation,. The direction of valve pressure relief should be marked on the process flow chart and noted in the pipeline axonometric drawing. If it is necessary to set an orifice but not set it, after the valve is closed, the liquid in the valve path will be heated and vaporized, which can easily burst the valve body. If the pressure relief is installed in the wrong direction, flammable or toxic media may be leaked to the operation and maintenance side.

Cryogenic valve manufacturing

The production of cryogenic valves requires strict manufacturing processes, the participation of special equipment and strict quality control on the component processing. After special low-temperature treatment, the rough-machined parts need to be placed in the cooling medium for several hours (2-6 hours) to release the stress. This can ensure good performance of the material in low temperature conditions, and prevent the valve from leakage caused by deformation due to a change in temperature. The assembly of the valve is also different from that of the ordinary valve. The parts need to be strictly cleaned to remove any oil stains to ensure the perfect performance.

Valves are the most common equipment in chemical enterprises. Installing valves may seem easy, but if not carried out according to relevant technical standards, it can lead to safety accidents. Today, we would like to share some experience and knowledge about valve installation with you.

I. Conduct a water pressure test during winter construction at negative temperatures.

• Consequence: Due to the rapid freezing inside the pipe during the hydrostatic test, the pipe is damaged by freezing.
• Measures: Try to conduct a water pressure test before winter construction, and blow out the water after the test, especially the water inside the valve must be completely removed, otherwise the valve may rust or even freeze and crack. When conducting a water pressure test in winter, the project must be carried out at a positive temperature indoors, and the water must be blown out after the test.

II. The pipeline system is not washed carefully before completion, and the flow and speed cannot meet the requirements of pipeline flushing.

• Consequences: Water quality cannot meet the operational requirements of the pipeline system, often resulting in reduced pipeline cross-sections or blockages.
• Measures: flushing should be carried out with the maximum design flow rate in the system or a water flow rate of not less than 3m/s. It should be considered as qualified if the water color and transparency at the outlet are visually consistent with those at the inlet.

III. Sewage, rainwater, and condenser pipes are concealed without undergoing a closed water test.

• Consequences: It may cause water leakage and cause losses to users.
• Measures: The closed water test work should be strictly inspected and accepted according to the specifications. The concealed installation of sewage, rainwater, condenser pipes, etc. in underground burial, ceiling, and between pipes should ensure no leakage.

IV During the hydraulic pressure strength test and tightness test of the pipeline system, the leakage inspection is not sufficient.

• Consequence: Leakage occurs after the pipeline system is running, affecting normal use.
• Measures: When testing the pipeline system according to design requirements and construction specifications, in addition to recording pressure values or water level changes within the specified time, it is particularly important to carefully check for leakage problems.

V. The flange plate of the butterfly valve is made of ordinary valve flange plate.

• Consequences: The dimensions of the flange plates for butterfly valves and ordinary valves are different. Some flanges have a small inner diameter, while the butterfly valve's disc is large, causing it to be unable to open or to open forcibly, resulting in damage to the valve.
• Measures: The flange plate should be processed according to the actual size of the butterfly valve flange.

VI. The valve installation method is incorrect.

For example, the water (steam) flow direction of the stop valve or check valve is opposite to the mark, the valve stem is installed downward, the horizontally installed check valve is installed vertically, the handle of the open-stem gate valve or butterfly valve has no space for opening and closing, and the valve stem of the concealed valve does not face the inspection door.

• Consequences: Valve malfunction, difficulty in switch maintenance, and often water leakage caused by the valve stem pointing downwards.
• Measures: Install the valve strictly according to the installation instructions. For the rising stem gate valve, leave enough space for the valve stem to extend and open. For the butterfly valve, fully consider the space for rotating the handle. The valve stem should not be lower than the horizontal position, and it should not be downward. For concealed valves, not only should there be an inspection door that meets the needs of opening and closing the valve, but also the valve stem should face the inspection door.

VII. The specifications and models of the installed valves do not meet the design requirements.

For example, the nominal pressure of the valve is less than the system test pressure; gate valves are used for water supply branch pipes with diameters less than or equal to 50mm; stop valves are used for hot water heating dry and vertical pipes; and butterfly valves are used for fire pump suction pipes.

• Consequences: It affects the normal opening and closing of the valve and the adjustment of resistance and pressure. It may even cause damage to the valve during system operation and necessitate repairs.
• Measures: Familiarize yourself with the application scope of various valves, and select the specifications and models of valves according to the design requirements. The nominal pressure of the valve should meet the requirements of the system test pressure. According to the construction specifications, when the diameter of the water supply branch pipe is less than or equal to 50mm, a globe valve should be used; when the diameter is greater than 50mm, a gate valve should be used. The hot water heating dry and riser pipes should use gate valves, and the suction pipe of the fire pump should not use butterfly valves.

VIII. The necessary quality inspection is not conducted according to the regulations before the installation of the valve.

• Consequences: The valve switch is not flexible during system operation, resulting in poor closure and leakage (steam) phenomena, causing rework and repair, and even affecting normal water (steam) supply.
• Measures: Before the installation of valves, pressure strength and tightness tests should be conducted. The tests should be conducted on 10% of each batch (of the same brand, same specification, and same model) and no less than one. For closed-circuit valves installed on the main pipe to cut off, strength and tightness tests should be conducted one by one. The pressure for valve strength and tightness tests should comply with the provisions of the Code for Acceptance of Construction Quality of Water Supply Drainage and Heating Works (GB 50242-2002).

IX. Improper installation of valves in high temperature environment.

• Consequence: leakage accident
• Measures: For high temperature valves over 200℃, they are at normal temperature during installation, but after normal use, the temperature rises, the bolts expand due to heating, and the gap increases, so they must be tightened again, which is called "hot tightening". Operators should pay attention to this work, otherwise leakage is likely to occur.

X. Valve flip-chip

• Consequences: Valves such as stop valves, throttle valves, pressure reducing valves, and check valves all have directionality. If installed upside down, the throttle valve will affect the effectiveness and lifespan of the valve; the pressure reducing valve will not work at all, and the check valve may even pose a danger.
• Measures: General valves have directional signs on the valve body; if not, they should be correctly identified based on the working principle of the valve. The valve cavity of the globe valve is asymmetric left and right, and the fluid should be allowed to pass through the valve port from bottom to top, which reduces fluid resistance (determined by shape) and saves effort when opening (due to the upward pressure of the medium). After closing, the medium does not press on the packing, which is convenient for maintenance. This is why the globe valve cannot be installed backwards. Gate valves should not be installed upside down (i.e., with the handwheel facing down), otherwise the medium will remain in the valve cover space for a long time, which can easily corrode the valve stem and is also prohibited for certain process requirements. At the same time, it is extremely inconvenient to replace the packing. For rising stem gate valves, do not install them underground, otherwise the exposed valve stem will be corroded due to moisture. For lift check valves, ensure that their valve discs are vertical during installation to facilitate flexible lifting. For swing check valves, ensure that their pin shafts are horizontal during installation to facilitate flexible swinging. Pressure reducing valves should be installed upright on horizontal pipelines, and should not be tilted in any direction.

Aeration butterfly valves are critical devices widely used in ventilation, air conditioning systems, flue gas emission, and dust removal systems. To ensure their long-term stable operation and to maximize their service life, regular maintenance and proper operation are essential.

1. Correct Installation

(1) Positioning: Ensure the aeration butterfly valve is installed in an appropriate location, avoiding exposure to high temperatures, corrosive media, and strong vibrations.

(2) Pipe Cleaning: Before installation, ensure the inside of the pipeline is clean and free of debris to prevent foreign objects from damaging the valve sealing surface.

(3) Proper Alignment: Ensure the valve is properly aligned with the pipeline to avoid stress concentration and sealing failure due to misalignment.

(4) Flange Connection: When connecting flanges, tighten bolts evenly to ensure uniform pressure on the sealing surface and avoid leakage.

2. Regular Maintenance and Upkeep

(1) Visual Inspection: Regularly inspect the valve's appearance to ensure the valve body is free of corrosion, cracks, or other damage, and that connection points are leak-free.

(2) Operation Testing: Regularly operate the valve to ensure that the opening and closing processes are smooth and that the operating torque is within normal limits.

(3) Lubrication Maintenance: Lubricate the valve stem and other moving parts to prevent wear due to friction. Use appropriate lubricants to avoid adverse effects on sealing materials.

(4) Cleaning Maintenance: Remove sediment and dirt from the valve body and pipeline to keep the interior clean and prevent blockages.

(5) Seal Replacement: Regularly check the condition of sealing components and promptly replace any aging or damaged seals to ensure proper sealing performance.

3. Correct Operating Method

(1) Slow Operation: Operate the valve slowly and evenly when opening or closing to avoid shocks and wear caused by rapid operation.

(2) Proper Adjustment: Avoid frequent adjustments of the valve position to minimize operating cycles and reduce wear on sealing components.

(3) Avoid Overpressure: Use the valve strictly within its design pressure range to prevent damage caused by overpressure operation.

(4) Prevent Foreign Matter Entry: Ensure the pipeline system is clean to prevent foreign matter from entering the valve, which can damage the sealing surface and valve disc.

4. Timely Handling of Faults

(1) Seal Failure: When seal failure is detected, promptly replace the sealing components to prevent further damage caused by leakage.

(2) Operation Inflexibility: If the operation is inflexible, check the lubrication of the valve stem and bearings, and lubricate or replace components as necessary.

(3) Corrosion: When corrosion is observed, clean the affected areas and take anti-corrosion measures. Replace damaged components if necessary.

5. Choose Appropriate Materials and Models

(1) Material Selection: Choose appropriate valve materials based on the characteristics of the medium to ensure the valve body and sealing components have sufficient corrosion resistance and abrasion resistance.

(2) Model Selection: Select the suitable valve model according to the working environment and operating conditions, ensuring that the valve's pressure and temperature ratings meet the requirements.

6. Develop Maintenance Plan

(1) Maintenance Interval: Develop a reasonable maintenance schedule based on the operating environment and conditions, and perform regular inspections and upkeep.

(2) Record Maintenance Activities: Document each maintenance and upkeep activity, including replaced components, operation test results, etc., to facilitate future maintenance.