What is a ball valve?
The ball valve is mainly composed of valve seat, ball, sealing ring, valve rod and other driving devices. The valve can be opened and closed by turning the valve rod 90 degrees. It is used to close, distribute, regulate the flow and change the flow direction of medium on the pipeline.
Ball valve came out in the 1950s. With the rapid development of science and technology, the continuous improvement of production technology and product structure, in a short period of 50 years, it has rapidly developed into a major valve class. In the western developed countries, the use of ball valve is increasing year by year.
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 is most suitable for use as a switch and shut-off valve.
Because the ball valve usually uses rubber, nylon and polytetrafluoroethylene as the seat sealing ring material, its use temperature is limited by the seat sealing ring material. The cut-off function of the ball valve is achieved by pressing the metal ball against the plastic valve seat under the action of the medium (floating ball valve). Under the action of certain contact pressure, the seat seal ring has elastic-plastic deformation in some areas. This deformation can compensate the manufacturing accuracy and surface roughness of the ball and ensure the sealing performance of the ball valve.
The working principle of the ball valve
The opening and closing part of the ball valve is a sphere with a circular passage, which revolves around the axis perpendicular to the passage, and the ball rotates with the stem to achieve the purpose of opening and closing the channel. Only 90 degrees of rotation and small torque can be used to close it tightly. Different driving devices can be assembled according to working conditions to form various ball valves with different control methods, such as electric ball valves, pneumatic ball valves, hydraulic ball valves and so on.
The working principle of the ball valve is:
When the ball valve rotates 90 degrees, at the inlet and outlet should all present the sphere, thus closing the valve and cutting off the flow of the medium.
When the ball valve turns 90 degrees, the ball inlet and outlet should all show the ball opening, thereby opening the flow. There is basically no flow resistance.
Working principle of ball valve
Structure principle of ball valve:
- 1. The ball valve is not limited by the installation direction, and the flow direction of the medium can be arbitrary. The fluid resistance is small, and the full diameter ball valve has no flow resistance.
- 2. The ball valve has the advantages of simple structure, relatively small volume, light weight and easy maintenance.
- 3. Close and reliable. It has two sealing surfaces, and the sealing materials of ball valves are widely used in various kinds of plastics. The sealing performance is good and can be completely sealed. It has also been widely used in vacuum system.
- 4. Ball valves are suitable for frequent operation, quick and easy opening and closing. The operation is convenient, the opening and closing are fast, and the full turn to full clearance is only 90 degrees of rotation, which is convenient for remote control.
- 5. Maintenance is convenient, the ball valve structure is simple, the seal ring is generally active, dismantling and replacement are more convenient.
- 6. The ball valve has good sealing performance. When fully opened or fully closed, the sealing surface of the ball and valve seat is separated from the medium. When the medium is passed, the sealing surface of the valve will not be eroded.
- 7. It has wide application range, small to several millimeters, large to several meters, and can be applied from high vacuum to high pressure.
- 8. Because the ball valve is wiped in the process of opening and closing, it can be used in the medium with suspended solids.
- 9. Ball valve fluid resistance is small. No vibration, little noise.
Classification of ball valves
Pneumatic ball valve
According to its structure, it can be divided into:
Fixed ball valve
Elastic ball valve
There are several commonly used classification methods for ball valves.
Structural principle of O type and V ball valve
There are many kinds of structures, but they are basically the same. They are all round and round core, mainly composed of valve seat, sphere, sealing ring, stem and other driving devices. The valve is rotated by 90 degrees to achieve the opening and closing of valves. The valve seat has different seat sealing according to different working conditions. The valve body has one piece, two sections and three sections.
O type ball valve structure:
The valve body of the O ball valve is internally provided with an intermediate through hole, and the sphere has a through hole which is equal to the diameter of the pipe. The sphere can rotate in the sealing seat, and a circular elastic body is arranged on each side of the pipeline to realize the sealing.By rotating the sphere 90 degrees, the direction of the through hole can be changed, thereby realizing the switch of the ball valve.
Structural schematic diagram of type O ball valve (closed)
Structural schematic diagram of type O ball valve (open)
O type ball valve principle:
When the O ball valve is fully opened, the two sides are unobstructed as an unobstructed valve, forming straight pipe passages and two-way seals. It has the characteristics of “self-cleaning” best performance, and is suitable for the two cut off occasions with particularly unclean and medium containing fibers. The ball core is always in contact with the valve during valve opening and closing. At the same time, the seal between the spool and the valve seat is achieved through the pre tight sealing force of the valve seat to the ball core, but due to its excellent mechanical and physical properties, the sealing performance of the soft sealing seat is excellent.
V type ball valve structure:
The V ball valve core has a V structure. The spool is a 1/4 spherical shell, with V notch, large circulation capacity, large adjustable range, shear force and close closure. It is especially suitable for fluid material with fibrous working conditions. In general, V ball valves are single sealed ball valves. It is not suitable for two-way use.
Structural schematic diagram of type V ball valve (closed)
Structural schematic diagram of type V ball valve (open)
V type ball valve principle:
Type V Edge, cut off impurities. During the rotation of the sphere, the sphere Type V The knife edge and the valve seat are tangent, so as to cut off the fibers and solid materials in the fluid, while the ordinary ball valves do not have this function, so it is easy to cause fiber impurities to be jammed when closing, which will bring great inconvenience to maintenance and maintenance. and Type V The spool of a ball valve is not stuck by fibers. In addition, the flange connection is adopted, so it is easy to assemble and disassemble without special tools, and maintenance is simple. When the valve is closed. The gap between the V type notch and the valve seat has the function of the shaped scissors, which has the function of self-cleaning and prevents the core from being stuck. The valve body, the valve cover and the valve seat adopt metal point to point structure respectively, and the valve rod spring with smaller friction coefficient is adopted, so the operation torque is small and stable.
Pneumatic ball valve
The advantages of stainless steel pneumatic ball valve are:
- 1. The stainless steel ball valve is made of Silicon Sol precision casting and connected with pneumatic actuator. It can not only act as a cut-off function, but also serve as a flow regulating function.
- 2. Diversified selection, through the use of different valve body, seat material, suitable for different conditions medium.
- 3. The application scope is broad. It can be used for atmospheric and atmospheric pressure applications, and can also be widely used in high temperature, high pressure and low temperature conditions.
- 4. Pneumatic stainless steel ball valves use gas as power source, the pressure is generally around 0.4-0.7MPa, relatively safe. If the air leakage, gas can be directly discharged, no pollution to the environment, and has high safety.
Stainless steel pneumatic ball valve accessories options:
Return device: also called limit switch, remote feedback switch signal (explosion-proof).
Solenoid valve: double action selects two position five links, single action selects two position three links (explosion-proof).
Triple connection: it can stabilize gas source, filter, cylinder and lubricating oil.
Cut off accessories: single electronic controlled solenoid valve, double electronic control solenoid valve, limit switch switch.
Adjustable accessories: Electrical positioner, pneumatic positioner and electrical converter.
Air source processing accessories: air filtration pressure reducing valve and gas source processing triplet.
Manual mechanism: Turn the handwheel mechanism and manually switch the valve.
Structure diagram of stainless steel pneumatic ball valve
|Nominal diameter||DN15 to DN300 (mm)|
|Nominal pressure||1, 1.6, 2.5, 6.4MPa|
|Driving form||Pneumatic control (compression 04-07Mpa)|
|Connection mode||Flange connection|
|temperature range||-40 ~ 450 C|
Single action (gas opening, gas shut down, gas source reset); double action (ventilation, ventilation).
|body material||Stainless steel 304, stainless steel 316, stainless steel 316L|
|control mode||Switch mode (switch two bit cut off control) (4-20mA analog signal)|
|Applicable medium||Steam, water, gas, corrosive medium Equal temperature Low temperature, High temperature and high pressure)|
Standard Specification for stainless steel pneumatic ball valves:
- 1. Test the main test: JB/T 9092, API 598.
- 2. Design and manufacture: GB12237-89, API608, API 6D, JPI 7S-48, BS5351, DIN3357.
- 3. Flange size: JB/T74 ~ 90 (JB74 ~ 90), GB9112 ~ 9131, HGJ44 ~ 76, SH3406, JIS B2212 ~ 2214, NF E29-211, DIN2543.
- 4. Structure length: GB12221-89, ANSI B16.10, JIS B2002, NF E29-305, DIN3202.
Installation instructions for pneumatic ball valves
Pneumatic ball valve before installation:
- 1. Ensure that the installation position of pneumatic ball valve is in the coaxial position, and the two flanges on the pipeline should be kept parallel. It is confirmed that the pipeline can withstand the weight of the pneumatic ball valve. If it is found that the pipeline can not bear the weight of the pneumatic ball valve, the pipeline should be equipped with corresponding support before installation.
- 2. Confirm whether there are impurities or slag in the pipeline, so we must clean the pipeline.
- 3. Check the nameplate of the pneumatic ball valve and carry out the operation with full opening and closing several times, confirm that the valve can work normally, and check the details of the valve once and again to ensure that the valve is intact.
- 4. Remove the protective cover at both ends, check whether the valve body is clean, and clean the inner cavity of the valve body. Because the sealing surface of the pneumatic ball valve is the shape of the ball, even minor debris may cause damage to the sealing surface.
- 1. Seal the flange between the pneumatic ball valve and the pipe flange according to the piping design requirements.
- 2. Bolts on flanges should be symmetrical, successive and evenly tightened.
- 3. When the ball valve adopts pneumatic actuator, the installation of gas source is completed according to the instructions.
- 4. Any section of the pneumatic ball valve can be installed on the upstream end. The pneumatic pipe ball valve of the handle can be installed in any position of the pipeline. If the ball valve of the electric pneumatic actuator is equipped, it must be installed vertically and the valve inlet and outlet are in a horizontal position.
- 1. After installation, start the pneumatic ball valve opening and closing several times. It should be flexible, uniform and pneumatic. Work is normal.
- 2. According to the design requirements of pipeline pressure, the sealing performance of pneumatic ball valve and pipe flange joint is detected after pressure.
Electric ball valve
Working principle of electric ball valve:
Application of electric ball valve:
- 1. For low temperature and low pressure, the material does not need to be adjusted too much.
- 2. Under high pressure and high temperature conditions, high temperature and high pressure materials should be chosen as electric ball valve materials, such as stainless steel and alloy, which can withstand high pressure and high temperature.
- 3. The internal parts of the electric ball valve need to be replaced to reduce the damage to the spool, and at the same time, facilitate the flow of the medium and avoid the coking and blockage of the electric ball valve.
- 4. In the case of electric ball valve opening, some vibration avoiding machinery can be installed to prevent the internal structure of the electric ball valve spool when it is opened.
Installation and maintenance of electric ball valve
The electric ball valve is a kind of valve used to control the pipeline medium and realize remote control. It is an important equipment in the industrial automation control system at present. Including pneumatic ball valves, and other valves can not be used in the process of continuous use. After storage or use for a certain period of time, maintenance and maintenance are necessary if we want to continue to ensure its effective work and extend its service life.
- 1. Ball Valve Under the closed condition, pressure fluid still exists inside the valve body.
- 2. Before repair, remove the pipeline pressure and make the valve in the open position; disconnect the power supply or gas source; disconnect the actuator from the bracket.
- 3. We must first find out that the upper and lower pipes of the electric ball valves have been dismantled before they can be disassembled and decomposed.
- 4. When we decompose and reassemble, we must be careful to prevent the sealing surface of the damaged parts, especially the non-metal parts. When we take out the O ring, we should use special tools.
- 5. Bolts on flanges must be tightened symmetrically, gradually and evenly.
- 6. Cleaning agent should be combined with the rubber parts, plastic parts, metal parts and working medium (such as gas) are compatible. When the working medium is gas, the metal parts can be cleaned by gasoline (GB484-89). Non metal parts are cleaned with pure water or alcohol.
- 7. Decomposed single parts can be cleaned by immersion. Metal parts with undecomposed nonmetallic parts remain clean, clean and clean with a cleaning agent. During cleaning, all grease, dirt, glue and dust adhered to the wall must be removed.
- 8. After cleaning, non-metallic parts should be removed immediately from the cleaning agent and not soaked for a long time.
- 9. After cleaning, it is necessary to assemble the cleaning agent after washing the wall, but it can not be shelved for a long time, otherwise it will rust and be contaminated by dust.
- 10. New parts need to be cleaned before assembly.
- 11. Use grease to lubricate. Grease should be compatible with ball valve metal materials, rubber parts, plastic parts and working media. When the working medium is gas, it can be used for example, special 221 grease. A thin layer of grease is coated on the surface of the sealing installation groove, and a thin layer of grease is coated on the rubber seal. A thin layer of grease is coated on the sealing surface and the friction surface of the valve stem.
- 12. Assembly should not allow metal detritus, fiber, grease (except for specified use) dust and other impurities, foreign bodies and other pollution, adhesion or stay on the surface of parts or enter the cavity.
Advantages and disadvantages of ball valve
It is evolved from the plug valve. Its opening and closing part is a ball. The ball is used to rotate 90 ° around the axis of the valve rod to achieve the purpose of opening and closing. The ball valve is mainly used to cut off, distribute and change the direction of medium flow on the pipeline. The ball valve with V-shaped opening also has good flow regulation function.
Advantages of ball valve:
- ①. It has the lowest flow resistance (actually 0);
- ②. It can be reliably used in corrosive medium and low boiling point liquid because it will not stick during operation (when there is no lubricant);
- ③. Tt can achieve complete sealing in a large range of pressure and temperature;
- ④. Tt can realize fast opening and closing, and the opening and closing time of some structures is only 0.05 ~ 0.1s, so as to ensure that it can be used in the automation system of the test bench. When the valve is opened and closed quickly, there is no impact during operation.
- ⑤. The spherical closing part can be automatically positioned at the boundary position;
- ⑥. The working medium is sealed reliably on both sides;
- ⑦. When the valve is fully open and closed, the sealing surface of the ball and the valve seat is isolated from the medium, so the medium passing through the valve at high speed will not cause the erosion of the sealing surface;
- ⑧. It has compact structure and light weight, so it can be considered as the most reasonable valve structure for low-temperature medium system;
- ⑨ the valve body is symmetrical, especially the welded valve body structure, which can well bear the stress from the pipeline;
- ⑩. The closing part can withstand the high pressure difference during closing.
- ⑪. The ball valve with fully welded valve body can be directly buried in the ground, so that the internal parts of the valve are not corroded, and the maximum service life can reach 30 years. It is the most ideal valve for oil and gas pipelines.
Disadvantages of ball valve:
- ①. Because the main sealing ring material of the valve seat is polytetrafluoroethylene, it is inert to almost all chemical substances, and has the comprehensive characteristics of small friction coefficient, stable performance, not easy to aging, wide range of temperature application and excellent sealing performance. But the physical characteristics of PTFE, including high expansion coefficient, sensitivity to cold flow and poor thermal conductivity, require that the design of valve seat seal must be based on these characteristics. Therefore, when the sealing material becomes hard, the reliability of the seal will be damaged. Moreover, the temperature resistance grade of polytetrafluoroethylene is low, and it can only be used under the condition of less than 180 ℃. Beyond this temperature, the sealing material will age. In consideration of long-term use, it is generally only used at 120 ℃.
- ②. Its regulating performance is worse than that of stop valve, especially pneumatic valve (or electric valve).
Installation and maintenance of ball valves
Installation of ball valve:
- 1. We must confirm that the pipeline and valve have been cleaned before operation.
- 2. The valve actuators operate according to the size of the input signal to drive the stem to rotate. When the forward rotating 1/4 ring (900), the valve is turned off. When rotating the 1/4 ring (900) in reverse direction, the valve opens.
- 3. When the direction of the actuator is parallel to the pipeline, the valve opens. When the arrow is perpendicular to the pipeline, the valve is closed.
Longer service life and maintenance free time will depend on several factors: maintaining a harmonious temperature / pressure ratio and reasonable corrosion data under normal working conditions.
Be careful: The fluid pressure in the valve body is still in the closed state.
Before repair, remove the line pressure and leave the valve in the open position.
Disconnect the power supply or gas source before maintenance.
Before the maintenance, the actuator and the bracket are detached.
1. Packing locking
If the stuffing culvert is in micro leakage, lock the stem nut.
Attention: do not lock tightly, usually lock 1 / 4 ring to 1 ring, leakage will stop.
2. Replace valve seat and seal.
Leave the valve in a semi open position and flush the potential hazardous substances inside and outside the valve.
Close the ball valve, remove the bolts and nuts on both sides of the flange, and remove the valve completely from the pipe.
Caution: please be careful to avoid scratching the surface of the valve stem and packing seal of the valve.
When you need to buy ball valves, for commercial, industrial or residential purposes it is recommended to know your options first. To do that you can go online for on the Internet you will come across lots of useful details on the most common valves and the best manufacturers. You can even search for China Valve Manufacturer that puts at your disposal a wide range of high-quality products, including China Ball Valve.
It is not every day that you decide to buy valves from China and it makes sense to do you research before you make a significant purchase. Different manufacturers have products of different qualities and you should find one that makes no compromises as far as quality is concerned. It is best to contact a China Valve Manufacturer with an impeccable reputation and years of experience in this field, one that will help you select the most suitable products and make a purchase you will not regret.
For this to happen, you need to be very clear about what you want. The more details you can provide to your China Valve Manufacturer the easier it will be for him to determine what you need and to make a recommendation that will suit your requirements. Selecting the right type of valve is a complicated process, one that requires knowledge and time. Numerous people complain about the fact that their valves do not function properly but this is because they have not chosen the best valves for the intended application.
If you do not want to be among them you should do your homework and you should see what criteria you should consider when you shop for a valve. Of course, the first one is the type of valve you need. For example, China Ball Valve is available in different types of materials. How do you know which one is right for you? Most individuals are not aware of the fact that when they select the seat insert material for the ball valve they have to consider service temperature, pressure and fluid compatibility.
It is impossible to make the best purchase when you lack proper information about the valve you need. You will find ball valves in flowing systems on ships, fire safe protection services but not in pharmaceutical, bioprocessing and food and beverage applications because they are difficult to clean. These valves are an excellent choice for start/stop applications and they are very popular because they act quickly. They are even suitable for throttling purposes and they are very common with gas and liquid media.
China Ball Valve can be used with challenging chemicals but it should not be used with slurries. There are different types of valves available on the market but the most common of them are floating ball design and trunnion mounted design. These valves are available in different materials, the most common of them being brass, bronze, copper, cast iron, stainless steel, metal alloys and plastics including PVC. Before you make a purchase you should become familiar with the specific attributes of the materials used to design the valve. Also, you should pay attention to type, concentration and temperature of the media.
As you can see, there are various aspects to be considered when shopping for a valve and one of them is calculating the correct performance requirements for the intended application. This being said, you can use the ball vale to start, stop and even regulate flow provided you pay attention to the above-mentioned aspects and you can make an informed decision. The more you know about your needs, the intended application and so on the easier it will be to make an educated purchase, one that you will not regret anytime soon.
Are you searching for a reliable China Valve Manufacturer, one that you can trust to deliver high-quality products? If this is the case you have come to the right place for we are happy to assist you. Shop with us now for ball valve or for other types of valves that you need and we will be happy to guide you through this process and to help you make an informed purchase. We do our best to cater to the needs of our customers and to inform them about their options. Feel free to contact us anytime for more details about our impressive selection of premium products.
Source: Best china ball valve supplier: www.epowermetals.com
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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Please notice that you might be interested in the other technical articles we’ve published:
How does a ball valve operate?
A ball valve is a device with a spherical closure unit that provides on/off control of flow. The sphere has a port, also known as a bore, through the center. When the valve is positioned such that the bore is aligned in the same direction as the pipeline, it is in open position and fluid can flow through it.
What are ball valves made of?
Ball valves are made using an assortment of materials, some of which include alloy steel, stainless steel and other steel types, and plastics (including CPVC and PVC).
Where is ball valve used?
Ball Valves are used for flow and pressure control and shut off for corrosive fluids, slurries, normal liquid and gases. They are used in the oil and natural gas industry, but also find a place in many manufacturing sectors, chemical storage, and even residential uses.
Can Ball valve be partially open?
Most ball valves are the quick-acting type. They require a 90-degree turn of the actuator lever to either fully open or completely close the valve. This feature, coupled with the turbulent flow generated when the ball opening is partially open, limits the use of ball valves as a flow control device.