A sleeved plug valve is a specific type of plug valve designed with a non-metallic sleeve or liner that surrounds the plug, creating a tight seal. This sleeve, often made from materials like PTFE (polytetrafluoroethylene), ensures a low-friction, corrosion-resistant seal, making the valve suitable for various applications where leakage prevention, durability, and chemical resistance are crucial. 1. How Sleeved Plug Valves Work In a sleeved plug valve, the plug rotates within a sleeve liner rather than directly against the metal body. This design reduces wear on the valve body and allows for smoother, more consistent operation. When the valve handle is turned, the plug rotates, opening or closing the flow path. The sleeve not only provides a tight seal but also allows for a self-lubricating effect, enhancing the valve’s longevity and performance. 2. Key Features and Advantages (1) Leakage Prevention The non-metallic sleeve acts as a reliable seal around the plug, minimizing the risk of external leakage. This feature is especially important in industries handling hazardous chemicals, as it prevents leaks and potential environmental contamination. (2) Corrosion and Chemical Resistance Sleeved plug valves are ideal for handling corrosive or abrasive fluids. The PTFE or other chemically resistant materials used for the sleeve make the valve suitable for environments where standard metal-on-metal contact would degrade over time. (3) Low Maintenance Due to their self-lubricating design, sleeved plug valves require less frequent maintenance compared to traditional plug valves. The sleeve also absorbs some wear, reducing the need for frequent replacements and improving overall valve durability. 3. Applications Industries such as chemical processing, water treatment, and oil and gas frequently use sleeved plug valves due to their reliability and ability to handle tough operating conditions. These valves perform well in systems that require minimal leakage, resistance to aggressive fluids, and easy maintenance.

1. Core Function of Gate Valves Gate valves are primarily used for on/off control in industrial pipelines, where the valve is either fully open or fully closed. This makes them particularly suited for applications that require an unobstructed flow path with minimal pressure drop. 2. Best for Straight-line Flow Systems One of the ideal applications for gate valves is in straight-line flow systems where flow restriction must be minimized. When fully open, the gate valve provides a clear, uninterrupted flow path, making it an excellent choice for such environments. 3. Widely Used in Isolation Services Gate valves excel in isolation services, where they are used to completely block or allow flow. This makes them essential for systems that require reliable shut-off, such as those in the oil, gas, and chemical industries. 4. Ideal for Large Diameter and High-Pressure Systems For large diameter pipelines and high-pressure applications, gate valves are highly effective. They are commonly used in industries where both large volumes of fluid and high pressure must be managed, thanks to their durability and reliable operation. 5. Limitations in Use However, gate valves are not recommended for throttling, frequent operation, or for use in systems with debris. These conditions can cause wear on the valve seat, potentially leading to reduced performance over time.

In the valve industry, gate valves are favored for their simple and reliable design, as well as their wide range of applications. However, despite their excellent performance in many fluid control scenarios, gate valves are not always the ideal choice. This article will explore situations where gate valves are not recommended, helping engineers and technical personnel make better decisions. 1. Not Suitable for Frequent Operation Gate valves are designed for fully open or fully closed positions, but they may not be the best choice for systems that require frequent operation. This is because opening and closing a gate valve requires multiple turns, making the process relatively slow. Frequent operation can lead to increased mechanical wear and shorten the valve's lifespan. Therefore, in applications that require quick response or frequent opening and closing, such as emergency shutdown systems, ball valves or butterfly valves, which can be quickly opened or closed, may be more appropriate. 2. Not Suitable for Throttling or Flow Regulation The primary function of a gate valve is for on/off control, and it is not suitable for regulating flow. If a gate valve is partially opened to throttle flow, the high-velocity fluid passing through can erode the gate and seat surfaces, leading to seal failure and possibly causing vibration issues. Additionally, a partially open gate valve can create flow turbulence and pressure drops, reducing system efficiency. For applications that require precise flow control, such as reaction control in chemical processes or flow regulation in water supply systems, control valves or ball valves are more suitable. 3. Limitations in High-Pressure or High-Temperature Applications While gate valves can be used in high-pressure systems, their performance is not always optimal in extreme high-pressure or high-temperature environments. For instance, in high-temperature steam systems, the sealing surfaces of a gate valve may expand or contract due to temperature fluctuations, leading to leaks or operational difficulties. In contrast, ball valves or globe valves generally offer better sealing and operational performance when handling high-temperature and high-pressure fluids. Additionally, gate valves in some high-pressure systems require higher torque to operate, increasing operational difficulty and maintenance costs. 4. Fluids Containing Solid Particles When handling fluids with solid particles, dirt, or sludge, gate valves are prone to clogging or having particles trapped between the gate and the seat. This can prevent the gate valve from fully closing and may even damage the valve. Solid particles can get lodged on the sealing surfaces of the valve, causing wear and reducing the valve’s lifespan. For fluids containing solid particles, knife gate valves, ball valves, or plug valves are more suitable, as they are designed to handle such conditions more effectively. 5. Space-Constrained Installation Environments Gate valves are typic...