echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Ball valve working principle, characteristics, classification, installation and maintenance introduction and Solutions

    Ball valve working principle, characteristics, classification, installation and maintenance introduction and Solutions

    • Last Update: 2009-09-19
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com
    Ball valve is evolved from plug valve It has the same 90 degree rotation lifting action, the difference is that the plug body is a sphere, with a circular through-hole or channel through its axis The ratio between the sphere and the passage port should be such that when the sphere rotates 90 degrees, the sphere should be present at the inlet and outlet, so as to cut off the flow The ball valve can be closed tightly only with 90 degree rotation operation and small rotation torque The completely equal inner cavity of the valve body provides a small resistance and straight passage for the medium It is generally believed that Zui ball valve is suitable for opening and closing directly, but in recent development, it has been designed to throttle and control flow The main features of ball valve are compact structure, easy operation and maintenance, suitable for general working media such as water, solvent, acid and natural gas, and also suitable for media with poor working conditions, such as oxygen, hydrogen peroxide, methane and ethylene The ball valve body can be integral or combined What is a ball valve: the ball valve uses a ball with a circular channel as the opening and closing part, and the ball rotates with the valve rod to realize the opening and closing action The opening and closing part of the ball valve is a ball with holes, which rotates around the axis perpendicular to the channel, so as to achieve the purpose of opening and closing the channel The ball valve is mainly used for opening and closing pipes and equipment media The ball valve has the same 90 degree rotation action The difference is that the plug body is a ball with a circular through hole or passage through its axis The ball valve is mainly used to cut off, distribute and change the flow direction of the medium in the pipeline It can be closed tightly with only 90 degree rotation and a small rotation torque The ball valve Zui is suitable for the use of switch and cut-off valves, but in recent development, the ball valve has been designed for throttling and flow control, such as v-ball valve Ball valve Its main features are compact structure, reliable sealing, simple structure, convenient maintenance, sealing surface and spherical surface are always closed, not easy to be eroded by media, easy to operate and maintain, suitable for general working media such as water, solvent, acid and natural gas, and also suitable for media with poor working conditions, such as oxygen, hydrogen peroxide, methane and ethylene, which are obtained in various industries Widely used The ball valve body can be integral or combined Main characteristics of ball valve: 1 The ball valve is not limited by the installation direction, and the flow direction of medium can be arbitrary The flow resistance is small, and the ball valve with full bore basically has no flow resistance 2 The ball valve has simple structure, small relative volume, light weight and easy maintenance 3 Tight and reliable It has two sealing surfaces At present, all kinds of plastics are widely used in the sealing surface materials of ball valves It has good sealing performance and can achieve complete sealing It is also widely used in vacuum system 4 The ball valve is suitable for frequent operation, with quick and light opening and closing It is easy to operate and fast to open and close It only needs to rotate 90 ° from full open to full close, which is convenient for remote control 5 The maintenance is convenient, the ball valve structure is simple, the sealing ring is generally movable, and the disassembly and replacement are relatively convenient 6 The ball valve has good sealing performance When the valve is fully open or closed, the sealing surface of the ball and the valve seat is isolated from the medium When the medium passes through, the valve sealing surface will not be eroded 7 It has a wide range of applications, ranging from small diameter to several millimeters and large diameter to several meters, from high vacuum to high pressure 8 The ball valve can be used in the medium with suspended solid particles due to its wiping property in the process of opening and closing 9 Ball valve fluid resistance is small 10 The ball valve has no vibration and low noise Classification of ball valve: ball valve can be divided into floating ball valve, fixed ball valve, elastic ball valve and oil sealed ball valve according to its structure; it can be divided into direct energy ball valve, angle ball valve and three-way ball valve according to its channel, and three-way ball valve can be divided into T-shaped and L-shaped According to the connection work, it can be divided into three types: threaded connection ball valve, flange connection ball valve and welding ball valve 1 The ball of the floating ball valve is floating Under the action of medium pressure, the ball can produce a certain displacement and press tightly on the sealing surface of the outlet end to ensure the sealing of the outlet end The floating ball valve has a simple structure and good sealing performance, but the load of working medium borne by the ball is all transmitted to the outlet sealing ring Therefore, it is necessary to consider whether the sealing ring material can withstand the working load of the ball medium When the ball is impacted by high pressure, the ball may shift This structure is generally used for medium and low pressure ball valves 2 The ball used to fix the ball valve is fixed and will not move after being pressed Fixed ball valves are equipped with floating seats Under the pressure of medium, the seats move, making the sealing ring tightly press on the ball to ensure the sealing Bearings are usually installed on the upper and lower shafts of the ball, with small operating torque, suitable for high-pressure and large-diameter valves In order to reduce the operating torque of ball valve and increase the reliability of sealing, oil sealed ball valve has appeared in recent years Special lubricating oil is injected between sealing surfaces to form a layer of oil film, which not only enhances the sealing performance, but also reduces the operating torque It is more suitable for ball valve with large diameter and high pressure 3 The ball of the ball valve is elastic Both the ball and the seat seal ring are made of metal materials The specific pressure of the seal is very large The pressure of the medium itself can not meet the requirements of the seal, so an external force must be applied This valve is suitable for high temperature and high pressure medium The elastic sphere is an elastic groove opened at the lower end of the inner wall of the sphere to obtain elasticity When the channel is closed, the wedge-shaped head of the valve rod is used to make the ball expand and compress with the valve seat to achieve sealing Before rotating the ball, first loosen the wedge-shaped head, and then the ball will return to its original shape, so that there is a small gap between the ball and the valve seat, which can reduce the friction and operating torque of the sealing surface 4 V-ball valve is a fixed ball valve and a single seat sealed ball valve Its regulating performance is Zui best among the ball valves Its flow characteristics are equal percentage, and its adjustable ratio is 100:1 Its V-notch and metal valve seat have shearing effect, which is especially suitable for medium containing fiber, small solid particles, slurry and so on 5 There are T-type and L-type three-way ball valves T-type can make three orthogonal pipelines connect with each other and cut off the third channel, which plays the role of diversion and confluence L-type can only connect two mutually orthogonal pipelines, and can not keep the third pipeline interconnected at the same time, but only play a role of distribution Precautions for installation and maintenance of ball valve: 1 The ball valve shall be provided with the position where the valve handle rotates; 2 The ball valve shall not be used for throttling 3 Ball valve with driving mechanism shall be installed vertically Product features: 1 The three-way ball valve adopts the integrated structure in structure, the sealing type of 4-face valve seat, less flange connection and high reliability The design realizes lightweight 2 The three-way ball core is divided into T-type and L-type, with long service life, large circulation capacity and small resistance 3 The ball valve According to the action type, there are two types: single action and double action The feature of single action type is that once the power source fails, the ball valve will be in the state required by the control system The nameplate of temperature and pressure limit shows the allowable operating pressure of the ball valve at Zui large and Zui small operating temperature Use PTFE or rtfe valve seat and seal, and the operating temperature shall be between - 290C and 2000c The operating temperature of other types of seats and seals shall be checked by ki factory The nominal pressure rating (PN) of the valve indicates the Zui high working pressure of the valve under normal temperature (for example, pn4.0 indicates that the Zui working pressure is 40 bar (4.0Mpa) when the operating temperature is between - 290C and 380c) Please refer to the corresponding instructions for the precautions of electric or pneumatic actuators Install 1) remove the protective covers on both sides of the flange end, and wash and clean when the valve is fully open 2) before installation, the whole machine shall be tested according to the specified signal (electricity or gas) (to prevent the vibration caused by transportation from affecting the use performance), and it can be installed online only after it is qualified (the wiring shall be in accordance with the circuit diagram of electric actuator) 3) before connecting with the pipeline, the residual impurities in the pipeline shall be washed and removed (these substances may damage the valve seat and ball) 4) during the installation, please do not use the actuator part of the valve as the lifting point to avoid damaging the actuator and accessories 5) this type of valve shall be installed in the horizontal or vertical direction of the pipeline 6) the pipeline near the installation point shall not be sagged or bear external force, and the pipeline support or support can be used to eliminate the deviation of the pipeline 7) after connecting with the pipeline, please cross lock the flange connecting bolts with the specified torque [edit this paragraph] operation and use 1) before operation, make sure that the pipeline and valve have been flushed 2) the operation of the valve drives the stem to rotate according to the input signal of the actuator: when the valve rotates 1 / 4 turn (900) in the forward direction, the valve is closed When rotating 1 / 4 turn (900) in reverse, the valve opens 3) when the direction indicator arrow of the actuator is parallel to the pipeline, the valve is open; when the indicator arrow is perpendicular to the pipeline, the valve is closed Ball valve maintenance has a long service life and maintenance free period, which depends on the following factors: normal working conditions, maintaining a harmonious temperature / pressure ratio, and reasonable corrosion data note: ● when the ball valve is closed, there is still pressure fluid inside the valve body ● before maintenance, release the pipeline pressure and keep the valve in the open position ● before maintenance, disconnect the power supply or air source ● before maintenance, separate the actuator from the bracket ● before disassembly and decomposition, it is necessary to find out that the upstream and downstream pipelines of the ball valve have removed the pressure ● during disassembly and reassembly, care must be taken to prevent damage to the sealing surface of parts, especially non-metallic parts When taking out the O-ring, special tools should be used ● bolts on the flange must be tightened symmetrically, step by step and evenly ● cleaning agent should be connected with rubber parts, plastic parts, metal parts and working medium (such as gas) in the ball valve
    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.