Description of pneumatic ball valve
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This post was last edited by feng_200108047 on 2011-7-5 08:39. ● The ball valve features a clear indication of its open and closed positions: the valve body, the ball, and the handle form one unit; when the handle points in the direction of the pipeline, the valve is open, while when the handle is perpendicular to the pipeline direction, the valve is closed； Even the worm gear head has an on/off indicator. ●Locking device design: To prevent incorrect operation of the switch, a flat-headed valve stem is used, with locking holes provided at the switch position to ensure that the valve remains in the correct position. ●A guided valve stem to prevent blowing out. The valve stem features an inverted or anti-backflow structure within the valve body and is sealed by a sealing ring; even in the event of a fire that causes the packing to burn out, the protruding part of the valve stem can remain in close contact with the sealing surface on the valve body, thereby effectively preventing leaks and the valve stem from coming loose and reducing the impact of accidents. ●Anti-static design: Springs and balls made of chromium-nickel stainless steel are used to ensure electrical conductivity between the ball, the valve stem, and the valve body, thereby completely dissipating the static electricity generated by friction between the non-metallic valve seat and the ball. ●Fire-resistant structure: In the event of a fire or abnormal temperature rise that causes PTFE to soften and burn, the fire-resistant sealing surface of the valve seat support ring can come into contact with the ball, providing a sealing effect and meeting the requirements of API607 and API6FA standards. In terms of fire safety design, a fire-resistant sealing lip is precisely fabricated on the inner side of the valve seat support surface; in the event that the valve is damaged due to a fire, this sealing lip creates a metal-to-metal seal with the ball. The valve gaskets are made of temperature-resistant graphite material, ensuring no leakage from the valve in case of a fire. ● Automatic pressure relief: When the medium trapped inside the valve chamber experiences abnormal pressure increases due to rising temperatures, the outlet end of the valve seat has an automatic pressure relief function. Additionally, a safety valve can be installed on the valve body as needed, thereby ensuring automatic pressure relief and safeguarding the pipeline’s safety. ●Sealed emergency repair: In the event of an unexpected failure of the valve seat seal due to impurities in the medium or a fire, the grease injection valve provides a quick connection to the grease gun, enabling easy and rapid injection of sealing grease into the valve seat area to reduce leaks. ●Two-way sealed fixed ball valve: The two-way sealed series of ball valves developed by the company features sealing on both the inlet and outlet sides, thereby ensuring more reliable sealing. Whether under pressure from only one side or with pressure applied to the middle chamber (regardless of the testing method used), zero leakage is achieved. The ball of a pneumatic ball valve is secured by upper and lower stem rods. During operation, the fluid pressure does not cause the ball to move toward the valve seat, and the valve seat is not subjected to excessive pressure that could cause it to deform. The valve stem is equipped with self-lubricating bearings to reduce friction, resulting in low switching torque; both valve seats are pre-tensioned using springs. Sealing is achieved by embedding polytetrafluoroethylene within a steel core, with a spring located at the rear of the steel ring to ensure that the valve seat remains in close contact with the ball. When the pressure in the valve’s interior rises abnormally and exceeds the force exerted by the spring, the valve seat retracts away from the ball, thereby achieving automatic pressure relief; once the pressure drops, the valve seat returns to its original position automatically. The advanced design of the structure ensures stable sealing performance for the fixed ball valve, simplifies operation, prolongs its service life, and makes it highly suitable for long-distance pipelines as well as ordinary pipelines. Universal ball valves come in two structural forms: full-bore and reduced-bore. Ball valves used in pipelines for transporting sticky and slag-prone media should be full-bore to facilitate the passage of regular wax-scraping blowers. Reduced-bore ball valves are suitable for use in pipelines that transport gases or fluids with physical properties similar to those of water, as they weigh about 30% less than full-bore ball valves, which helps to reduce the load on the pipelines and lower costs. A ball valve is a rotary valve that rotates by 90°; it features excellent sealing performance. (Full-bore ball valves) have a high flow coefficient and a low flow resistance coefficient, possess a simple structure, a long service life, and are easy to maintain. The product is widely used in system control across industries such as chemicals, petroleum, light textiles, power, food and pharmaceuticals, refrigeration, and papermaking.
I’ve learned it; it would be great if it could be formatted properly
A pneumatic ball valve is a ball valve equipped with a pneumatic actuator. The actuator operates at a relatively fast speed, and it does not require manual operation, thus saving significant amounts of human resources and time. The pneumatic ball valve evolved from the globe valve. It has the same 90-degree rotation action, but the difference is that the plug body is spherical, with a circular hole or passage running through its axis. The ratio between the sphere and the opening should be such that when the sphere rotates 90 degrees, the entire area at the inlet and outlet should be covered by the sphere, thereby blocking the flow. A pneumatic ball valve can be closed tightly with just a 90-degree rotation using air, and requires only a very small torque. The completely equal inner cavity of the valve provides a flow path with very low resistance and a direct route for the medium. It is generally believed that ball valves are most suitable for direct on-off operation, but recent developments have designed ball valves to also enable throttling and flow control. The main advantages of ball valves are their compact structure, ease of operation and maintenance. They are suitable for use with common working media such as water, solvents, acids, and natural gas, as well as for media under harsh operating conditions, such as oxygen, hydrogen peroxide, methane, and ethylene. The ball valve body can be integral or modular. Range: This manual applies to pneumatic ball valves with flanged connections. Composition: It consists of a pneumatic actuator and the ball valve body, which are connected together using brackets and coupling shafts. Usage limitations: Temperature and pressure restrictions – The nameplate indicates the maximum operating pressures allowed for the ball valve at its maximum and minimum operating temperatures. With valve seats and seals made of PTFE or RTFE, the operating temperature should be between –290°C and 2000°C. The operating temperatures for other types of valve seats and seals shall be verified by the KI factory. The nominal pressure class (PN) of the valve indicates the maximum operating pressure under normal temperature conditions. (For example: PN4.0 indicates that the maximum operating pressure at operating temperatures ranging from –290°C to 380°C is 40 Bar (4.0 MPa)). For precautions regarding electric or pneumatic actuators, refer to their respective manuals. For the installation of pneumatic ball valves, remove the protective covers on both sides of the flange end, and clean the valve while it is fully open. Before installation, the entire unit should be tested using the specified signals (electrical or pneumatic) (to prevent vibrations caused by transportation from affecting its performance); it can only be installed after passing the tests. Before preparing to connect to the pipeline, it is necessary to flush and remove any residual impurities from the pipeline (such substances may damage the valve seat and ball). During installation, do not use the actuator part of the valve as a lifting point to avoid damaging the actuator and its accessories. . Valves of this type should be installed horizontally or vertically in the pipeline. The pipes near the installation point must not sag or be subjected to external forces; pipe supports or braces can be used to eliminate any deviation in the piping. After connecting to the pipeline, cross-secure the flange connection bolts with the specified torque. Operation and use of pneumatic ball valves: Before operation, it is necessary to ensure that the pipelines and valves have been flushed. The operation of the valve is accomplished by the actuator using the input signal to rotate the valve stem; when it rotates 1/4 turn (90 degrees) in the forward direction, the valve closes. The valve opens when rotated 1/4 turn (900) in the reverse direction. When the actuator’s direction indicator arrow is parallel to the pipeline, the valve is in the open position ； When the indicator arrow is perpendicular to the pipeline, the valve is in the closed position. Maintenance: A long service life and maintenance-free period depend on several factors, including normal operating conditions, maintaining an appropriate temperature/pressure ratio, and having accurate data regarding corrosion. Note: Even when the ball valve is closed, there is still pressurized fluid inside the valve body. Before carrying out maintenance, relieve the pressure in the pipeline and ensure the valve is in the open position. Disconnect the power or gas supply before maintenance, and separate the actuator from its support. Re-tighten the packing area; if there is any slight leakage at the packing site, tighten the valve stem nut further. Be careful not to over-tighten it – usually tightening it by another 1/4 turn to 1 full turn will stop the leakage. Replace the valve seat and seals. Disassembly: Put the valve in a semi-open position, and flush it to remove any hazardous substances that may be present inside or outside the valve body. Close the ball valve, remove the connection bolts and nuts from both flanges, and then completely remove the valve from the pipeline. Remove the drive device and actuator in sequence, as well as the connection brackets, lock washers, valve stem nuts, butterfly springs, gland components, wear-resistant plates, and valve stem packing. Remove the bolts and nuts that connect the valve cover to the valve body, separate the valve cover from the valve body, and take out the valve cover gasket. Ensure that the valve ball is in the “closed” position; this makes it easier to remove it from the valve body. Next, remove the valve seat. Gently push the valve stem downward through the hole in the valve body until it is completely removed, then take out the O-rings and the packing at the bottom of the valve stem. Note: Please proceed with care to avoid scratching the surface of the valve stem or the sealing parts of the valve body’s packing gland. Reassemble the pneumatic ball valve. Clean and inspect the removed parts; it is highly recommended to replace seals such as the valve seat and valve cover gaskets with spare parts. Assemble the valve in the reverse order of disassembly. Tighten the flange connection bolts using the specified torque, and also tighten the valve stem nuts using the specified torque. After installing the actuator, send the appropriate signal to rotate the valve stem, thereby moving the valve core to the open or closed position. If possible, conduct pressure testing and performance tests on the valve in accordance with relevant standards before reinstalling it in the pipeline. Model designation: In valves like the Q11S-16C mentioned earlier, the “S” indicates an older method, where “S” stood for plastic seals. Nowadays, “F” is used to indicate fluoroplastic or polytetrafluoroethylene materials