Ball valves

Ball valves manufacturer

As a Chinese ball valve supplier with a variety of international certifications and praise from customers, we produce high performance ball valve series products and also customized solutions to meet valve operating conditions and manufacturing standards in different sectors.

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Precautions for purchasing ball valves

When purchasing, customers often ask us how to choose the model of the ball valve?  Many customers only send general models, but there are no requirements for the material, pressure, temperature, etc. of the ball valve. When the goods are received, they find that the ball valve is not easy to use. In fact, the selection of the ball valve has a great relationship with the medium, pressure and temperature.

1. Medium

Under normal medium temperature and low pressure conditions, carbon steel body, 304 core, PTFE material of soft seal valve seat is recommended. For corrosive fluids, the stainless steel valve body can be selected. Material 304 or 316 is recommended. For sulfuric acid there is also desulfurization and denitrification. For the working conditions it is recommended to use two-phase steel. 
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2. Temperature

The operating temperature of the ball valve is below 150 degrees, we usually choose PTEF, for the working conditions in the range of 150 to 200 degrees, it is recommended to use PPL or EK material, if the temperature exceeds 200 degrees, we can choose watertight ball valves.
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3. Pressure

The pressure parameters of conventional ball valves are 16kg, 25kg, 40kg, 64kg and even more, we can also customize the models. If the valve selection is not good, the life will not be long.
It is very important to choose the right ball valve!
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Why choose XinHui ball valve?

Small fluid resistance

A full-bore ball valve has almost no flow resistance. It will not get stuck when working (when there is no lubricant), and can be used in industries with low flow resistance such as corrosive media and low-boiling liquids.

Wide range of applications

Our ball valve. It has a wide range of applications, with diameters ranging from small to several millimeters to several meters, from high vacuum to high pressure, and can be used in different industries and various harsh valve conditions.

long lifespan

Our ball valves are also easier to use than gate valves, have a lower failure rate, and last longer.

Strong sealing performance

The sealing surface of the ball valve produced by us has good airtightness and has been widely used in vacuum systems. It has also been widely used in ultrafiltration devices.

Easy to operate

Our ball valve opens and closes quickly, and only needs to rotate 90° from full opening to closing, which is conducive to long-distance operation.

Easy to maintain

The structure of the ball valve is simple, the sealing ring is generally movable, and the disassembly and replacement are very convenient.

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We are not only a manufacturer of valves, but also a disseminator of industry knowledge

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EXPLORE STORY

All You Need to Know About Ball Valves

01

Introduce

what is a ball valve

The ball valve came out in the 1950s.The opening and closing parts of the ball valve are driven by the valve stem and make a rotary motion around the axis of the ball valve.It can be used for fluid regulation and control. Among them, the hard-sealed V-shaped ball valve has a strong shear force between the V-shaped ball core and the metal valve seat of hard alloy surfacing, and is especially suitable for fibers and tiny solid particles, etc. medium. Such valves are generally installed horizontally in the pipeline. 
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What is a ball valve used for?

The ball valve is mainly used to cut off, distribute and change the flow direction of the medium in the pipeline.It only needs to rotate 90 degrees and a small torque to close tightly. Therefore, the ball valve is most suitable for use as an on-off shut-off valve. In addition, the multi-port ball valve can not only flexibly control the confluence, diversion and switching of the flow direction of the medium on the pipeline, but also can close any channel and connect the other two channels.

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02

Introduce

03

Introduce

how does a ball valve work

Start Process
In the closed position of the valve, the ball is pressed against the valve seat by the mechanical pressure of the valve stem. When the handwheel is turned counterclockwise, the valve stem moves in the opposite direction.
The rod continues to lift and interacts with the guide pin in the helical groove of the valve stem, so that the ball starts to rotate without friction until it reaches the fully open position, the valve rod is lifted to the limit position, and the ball rotates to the fully open position.
Closing Process
To close, turn the handwheel clockwise, the stem begins to descend, and the ball leaves the seat and begins to rotate. Continue to rotate the handwheel, the valve stem receives the action of the guide pin embedded in the upper spiral groove, which makes the valve stem and the ball rotate 90 degrees at the same time. When it is about to close, the ball has rotated 90 degrees without contacting the valve seat. . In the last few turns of the handwheel rotation, the foot-shaped plane at the bottom of the hair rod mechanically presses the ball obliquely, making it tightly pressed on the valve seat to achieve complete sealing. 
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ball valve structure

The ball valve is mainly composed of valve core, valve body base, valve body, sealing packing, valve stem, valve stem guide pin, valve cover, hand wheel, etc. If there is a spiral groove on the stem of the fixed ball valve, the stem guide pin can control the up and down movement and horizontal rotation of the valve core, but cannot move horizontally. , When the valve is closed, the side wall of the valve core cooperates with the base of the valve body to play a sealing role. The valve body seat is located on one side of the valve plug. When the valve is closed, it is pressurized by the medium and moves to the valve core, and the valve core and the valve core are tightly fitted to prevent the medium from leaking.

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Ball Valve Structure

04

Introduce

05

Introduce

How to Install a Ball Valve

The first is the preparation before installation. It is necessary to carefully check whether the material, pressure, diameter, thread type and other marks of the valve meet the requirements of the working conditions. It is necessary to rinse the foreign matter in the pipeline, otherwise the sealing surface will be damaged and the sealing performance of the valve will be reduced. . Second, the choice of installation location, the valve is generally installed horizontally, it is best to choose a location that is convenient for operation and maintenance. Third, use raw tape or apply thread tightening glue for auxiliary sealing during installation. Special attention is that when tightening, you can only twist the wrench at the hexagonal or octagonal position closest to the valve port. Do not use other components of the valve to tighten, otherwise the valve will be seriously damaged. Fourth, screw the pipe and the valve together evenly during the installation process to ensure that the valve and the pipe are in the same line, so as to prevent the valve from leaking due to the stress of the pipe. Fifth, the flow direction requirements, such as the two-way seal of our company’s ball valve, have no flow direction requirements, and the installation direction can be adjusted according to the site space and operating habits. Doing these five points can basically ensure the installation of the valve.

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Ball valve application scenarios

The ball valve is suitable for the pipeline system with light structure, small pressure difference and corrosive medium. Ball valves can also be used in cryogenic installations and piping systems. In the oxygen pipeline system in the metallurgical industry, a ball valve that has undergone strict degreasing treatment is required. When the main line in the oil pipeline and gas pipeline needs to be buried underground, a full-bore welded ball valve is required. In the pipeline system with working temperature above 200 degrees in petroleum, petrochemical, chemical power, and urban construction, a metal-to-metal sealed ball valve can be selected.
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06

Introduce

OEM & ODM XinHui Ball Valves Applications

PTFE lined ball valve & Fluorine Lined Ball Valve

Q41F4 F46 Fluorine lined ball valve - recommended for chemical industry

The fluorine-lined ball valve has small fluid resistance, smooth inner wall and smooth flow passage, which is the smallest fluid resistance among all valves. Using special molding process, the lining material is lined on the inner wall of the valve shell, which can resist the corrosion of strong acid and alkali medium. The lining spherical surface is combined with the PTFE valve seat, which has good sealing performance and achieves zero leakage.

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Ash unloading ball valve (coal injection ball valve) - recommended for coal chemical industry

The ash discharge ball valve is often used to cut off or connect the medium in the mining, refining and processing of oil, natural gas, coal and ore and pipeline transportation systems; especially suitable for blast furnace pulverized coal injection, dust and solid powder pipeline systems, air pipelines and spray guns Pipelines, etc. The ash discharge ball valve is used for the equipment for conveying pulverized coal, control gas, particle-containing fluid and powder solid medium. It is a suitable valve for pulverized coal injection in metallurgy and mineral processing.

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Fully Welded Forged Steel Fixed Ball Valve - Recommended for Petroleum Industry

Forged steel fully welded ball valves can be used in various types of petroleum pipeline equipment. The fully welded ball valve can be used reliably for a long time, without maintenance, and the operation is simple. The installation of the valve is more convenient, which saves the engineering time and reduces the engineering cost. The service life of the forged steel fully welded ball valve is the same as that of the pipeline.

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DQ41F Cryogenic Ball Valve

DQ41F Cryogenic Ball Valve-Recommended for natural gas industry

The main features of the low temperature ball valve are its compact structure, reliable sealing, simple structure and convenient maintenance. The low temperature floating ball valve is also suitable for medium with harsh working conditions and is widely used in the natural gas industry.

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DYQ340F Top Entry Eccentric Half Ball Valve

DYQ340F Top Entry Eccentric Half Ball Valve-Recommended for mining industry

The top-loading eccentric half-ball valve is suitable for the mining industry. The ball and the valve seat of the top-loading eccentric half-ball valve are completely separated, which eliminates the wear of the sealing ring and overcomes the problem that the traditional ball valve seat and the sealing surface of the ball are always worn. Non-metallic elastic material It is embedded in the metal seat, and the metal surface of the valve seat is well protected.

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Testimonials

かわいけんじ
かわいけんじ
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I am very happy to be invited to share our long-term cooperation experience for the xinhui website! Japan is very strict on the production standards of valves, but Xinhui has never let me down in our cooperation for so many years, so I recommend you to start your valve business with them too!
Tony
Tony
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Hello everyone, I'm Tony, I'm very happy to share the story between us and Xinhui Valve, the CEO of Xinhui company must ask me to shoot this video, I refused at first, but their work is done so well , I think I can't help but tell everyone that my cooperation with Xinhui is really good, so I recommend them! After working with them I believe you are too!
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Ball valve : Ultimate Guide

Introduce in detail the ball valve type code, drive mode code, connection form code, structure type code, ball valve seat material code, pressure grade code, valve body material code and flange sealing surface form code. The combination of these knowledge is a relatively complete and detailed model meaning and editing method of the ball valve.

The main feature of stainless steel ball valve is its compact structure, easy operation and maintenance. Different types of ball valves can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media. The ball valve body can be integral or combined. This type of valve should generally be installed horizontally in the pipeline.

Classification of ball valves:

1. Stainless steel pneumatic ball valve, stainless steel electric ball valve, stainless steel manual ball valve. Stainless steel ball valve material is divided into 304,316,321 stainless steel ball valve.

2. The stainless steel ball valve relies on the rotating valve core to make the valve unblocked or blocked. The ball valve switch is light, small in size, can be made into a large diameter, reliable sealing, simple structure, convenient maintenance, sealing surface and spherical surface are often in a closed state, not easy to be eroded by media, and are widely used in various industries. Only its closing part is a sphere, and the sphere rotates around the center line of the valve body to open and close a valve.

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Commonly used ball valve models:

V-type ball valve model: 

VQ640F, VQ40F, VQ940F, VQ641H, VQ70F, VQ670F, VQ970F, VQ71H, VQ671H, VQ971H;

Insulation ball valve model: 

BQ41F, BQ641F, BQ941F;

Stainless steel ball valve model:

 Q41F-16P, Q641F-10P, Q941F-25P, Q41H-40P, Q641H-10P, Q941H-25P;

Fluorine-lined ball valve model: 

Q41F46, Q641F46, Q941F46;

Low temperature ball valve model: 

DQ41F, DQ41H, DQ41V;

Wafer type ball valve model: 

Q71F, Q671F, Q971F, Q71H, Q671H, Q971H,

High temperature ball valve model: 

Q41M, Q641M, Q941M, Q41PPL, Q641PPL, Q941PPL,

Fixed ball valve model: 

Q347F, Q647F, Q947F, Q347H, Q647H, Q947H, Q347W, Q647W, Q947W;

Turbine ball valve model: 

Q341F, Q341H, Q341W, Q341Y;

Welded ball valve model: 

Q61F, Q361F, Q61H, Q661F, Q661H, Q961F, Q961H;

Eccentric hemisphere valve model: 

Q340F, Q640F, Q940F, Q340H, Q640H, Q940H, Q340Y, Q640Y, Q940V;

Top entry ball valve model: 

SQ340F, SQ940F, SQ340H, SQ940H, SQ347H, SQ647H, SQ947H, DYQ340F, DYQ640F, DYQ940F;

Three-way ball valve model: 

Q44F, Q45F, Q44H, Q45H, Q644F, Q645F, Q644H, Q645H, Q944F, Q945F, Q944H, Q945H;

Four-way ball valve model:

 Q46F, Q46H, Q646F, Q646H, Q946F, Q946H.

Ball valve model code meaning:

1. The meaning of the ball valve type code:

Q means ball valve; 

GQ means track; 

VQ means V-type ball valve; 

BQ means insulation ball valve; 

KQ means anti-sulfur ball valve;

DQ means low temperature ball valve; 

MQ means pulverized coal ball valve; 

VQ means liquefied balloon valve; 

QE means extension rod ball valve; 

QO Represents oxygen ball valve; 

QF represents fire-proof ball valve; 

QS represents reduced diameter ball valve

2. The meaning of the code name of the drive mode of the ball valve:

0 means electromagnetic; 

1 means electromagnetic-hydraulic; 

2 means electric-hydraulic; 

3 means pot wheel; 

4 means spur gear; 

5 means bevel gear; 

6 means pneumatic; 

7 means hydraulic; 

8 means gas-liquid linkage; 

9 Indicates electric

3. The meaning of the ball valve connection form code:

1 means internal thread; 2 means external thread; 4 means flange; 6 means welding; 7 means clamp; 8 means clamp;

0 means hemisphere straight; 1 means floating ball full pass; 4 means floating ball three-way L type; 5 means floating ball three-way T type; 6 means four-way type; 7 means fixed ball full pass-through; 8 means fixed ball three-way type ;9 means floating ball tee V type

5. The meaning of the material code of the ball valve seat:

F means polytetrafluoroethylene; 

E means reinforced polytetrafluoroethylene; 

D means medium temperature carbon fiber; 

PPL means para-polyphenylene; 

N means nylon; 

M means wear-resistant carbon fiber; 

C means high temperature wear-resistant carbon fiber; 

V means cemented carbide ;

H means alloy steel; 

Q means sugar porcelain; 

T means copper alloy; 

X means rubber

6. The meaning of the pressure grade code of the ball valve:

16 means the pressure is 16kg (1.6Mpa) and the maximum can reach 64Mpa;

150LB means American standard pound pressure, the maximum pressure rating can reach 2500LB (150LB=1.6MPA/300LB=2.5-4.0mpa/400LB=6.4mpa/600LB=10mpa); 5K means daily pressure, the maximum pressure is 63K;

7. The meaning of the material code of the ball valve body:

A titanium and titanium alloy, C carbon steel, l chromium molybdenum steel, P18-8 series stainless steel, RMo2Ti series stainless steel, S plastic.

8. The meaning of the form code of the sealing surface of the ball valve flange:

RF means raised surface; FM means concave surface; M means convex surface; TG means rod groove surface; FF means full plane; RJ means ring connection surface; SW means socket welding; BW means butt welding; TH means thread

A ball valve is a valve with a ball as the closing part, which is mainly composed of a valve body, a valve seat, a ball, a valve stem, a handle (or other driving devices). It is driven by the valve stem and rotates around the axis of the ball valve. It is mainly used for cutting, distributing and changing the flow direction of the medium in the pipeline. For a wide variety of ball valves, including different working principles, media and application sites, users should choose different types of ball valves according to their requirements.
According to the structure, it can be divided into:
  • floating ball valve
  • fixed ball valve
  • elastic ball valve

Floating ball valve

The ball of the floating ball valve is floating. Under the action of the 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 structure of the floating ball valve is simple and the sealing performance is good, but the load of the ball bearing the working medium is all transferred to the outlet sealing ring. Therefore, it is necessary to consider whether the material of the sealing ring can withstand the working load of the ball medium. , the sphere may be offset. This structure is generally used for medium and low pressure ball valves.
The main structural features of the floating ball valve are:
1. The valve is provided with open and closed position indication
2. Locking device
3. Stem anti-flying structure
4. Anti-static device
5. Fireproof structure
6. Unique valve seat sealing structure
7. The middle flange (the connection between the valve body and the left body) has no leakage structure

Fixed ball valve

The ball of the ball valve is fixed and does not move under pressure and, after being pressurized by the fluid, the valve seat moves, so that the sealing ring is pressed firmly on the ball to ensure the seal. The bearings are generally installed on the upper and lower shafts with the ball and the operating torque is small, suitable forhigh pressure and large diameter valves.
In order to reduce the operating torque of the ball valve and increase the reliability of the seal, ball valves with oil seal have appeared in recent years, that is, a special lubricating oil is injected between the sealing surfaces to form a film of oil, which not only improves the sealing performance, but also reduces the operating torque.

Elastic ball valve

The ball of the orbital ball valve is elastic. Both the ball and the valve seat sealing ring are made of metal materials, and the sealing specific pressure is very large. The pressure of the medium itself cannot meet the sealing requirements, and external force must be applied. This valve is suitable for high temperature and high pressure medium.
The elastic sphere is obtained by opening an elastic groove at the lower end of the inner wall of the sphere to obtain elasticity. When closing the channel, use the wedge head of the valve stem to expand the ball and press the valve seat to achieve sealing. Before turning the ball, loosen the wedge head, and 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. According to the ball structure, it can be divided into straight-through ball valves, hemispherical ball valves, V-shaped ball valves, three-way ball valves, etc.
1. Straight-through ball valve
The straight-through type refers to the horizontal type and the corresponding angle type, while the DC type is generally a kind of directly flowing valve without a curved flow channel in the middle.
The straight-through ball valve is the simplest, most common and widely used, even for fluids containing solid or high viscosity particles.Compared with the gate valve, the globe valve has a simpler structure and is more convenient to manufacture and maintain, a sealing surface is not easy to wear and scratch, the sealing performance is better, and the service life is longer. Furthermore, the valve disc stroke is small during opening and closing and the opening and closing time is shorter.
2. Hemispherical ball valve
The hemispherical valve adopts the eccentric-wedge tightening principle in its structure. The center of rotation of the valve body and the valve core (ie the axis of the valve stem) is offset from the geometric center of the sealing spherical surface of the valve core by a radial dimension, and also has an offset dimension from the sealing surface of the valve seat on the axis of the valve body passage.
The sealing pair is Metal – metal, it contacts under the action of external force, the valve relies on two eccentrics to achieve self-locking closure, and the reasonable selection of eccentricity makes the self-locking angle smaller than the friction angle.
If the self-locking angle is too small, it is easy to close, but it is very difficult to open. If the angle is large, although the opening force is small, the closing torque increases rapidly. After repeated tests on the test bench, it is very important to determine the reasonable eccentricity of the two combinations. The self-locking properties ensure a tight seal. Its structure has been continuously improved for many years, and its performance is stable. It is light and flexible in operation, has a long service life, can automatically compensate for wear, and can automatically remove scale due to eccentric wedge tightness.
3. V-type ball valve
The V-type ball valve is a fixed ball valve, and it is also a single-seat sealed ball valve. The adjustment performance is the best in the ball valve. It has a shearing effect between its V-shaped notch and the metal valve seat, and is especially suitable for media containing fibers, tiny solid particles, and slurry.
4. Three-way ball valve
The three-way type can be divided into:
  • T-type: can connect three orthogonal pipes to each other and cut off the third channel, and play the role of diversion and confluence.
  • L-type: can only connect two pipes that are orthogonal to each other, and cannot maintain the interconnection of the third pipe at the same time, and only plays a distribution role.
Features
1. The three-way ball valve adopts an integrated structure in structure, and the four-sided valve seat adopts a sealing type, with few flange connections, high reliability, and lightweight design.
2. The three-way ball core is divided into T-type and L-type, with long service life, large flow capacity and low resistance.
3. The ball valve is divided into 2 types, according to the action type:
  • Single-acting (characterized in that once the power source fails, the ball valve will be in the state required by the control system)
  • Double-acting
4. According to the connection method, it can be divided into:
  • threaded connection ball valve flange connection ball valve
  • welded ball valve
  • clamp quick connection ball valve
  • wafer connection ball valve
1. Threaded connection ball valve
The ball valve with threaded connection requires less material and the cost is the lowest. We recommend this connection method for ball valves below DN50. Of course, the maximum diameter of the threaded ball valve can be DN100. The main thread forms are G thread, NPT thread, PT thread, etc. This kind of connection is usually processed into tapered pipe or straight pipe thread at the inlet and outlet ends of the valve, which can be connected to the tapered pipe thread joint or pipeline. Because of the potential for large leakage channels in this connection, sealants, sealing tape, or fillers can be used to plug these channels. If the material of the valve body can be welded, but the coefficient of expansion is very different, or the operating temperature varies widely, the threaded connection must be welded. Threaded ball valves mainly include: one-piece threaded ball valve, two-piece threaded ball valve, and three-piece threaded ball valves.
2. Flanged ball valve
The flanged ball valve is easy to install and disassemble. However, it is heavier than the threaded valve, and the corresponding price is also higher. Therefore, it is suitable for pipeline connections of various diameters and pressures. However, when the temperature exceeds 350 degrees, since the bolts, gaskets and flanges become loose, the load of the bolts will also be significantly reduced, and there may be leakage in the flange connection with great stress. This is also one of the common connection methods of VTON.
According to the shape of the joint surface, the flanged ball valve can be divided into:
1) Smooth: used for valves with low pressure. Processing is more convenient
2) Concave-convex: high working pressure, medium-hard washers can be used
3) Tongue and groove: gaskets with larger plastic deformation can be used, which are widely used in corrosive media and have better sealing effect.
4) Trapezoidal groove: use an oval metal ring as a gasket, which is used for valves with a working pressure of ≥64 kg/square centimeter, or high temperature valves.
5) Lens: The gasket is in the shape of a lens and is made of metal. Used for high pressure valves with working pressure ≥100 kg/cm², or high temperature valves.
6) O-ring: This is a newer flange connection form, which is developed with the emergence of various rubber O-rings. It is more reliable than ordinary flat washers in terms of sealing effect.
3.Welded ball valve
There are two types of connection:
1) High-pressure threaded belt welding or direct butt-welding and socket-welding ball valves are suitable for various pressures and temperatures, and are more reliable than flange connections when used under heavy load conditions. However, it is difficult to disassemble and reinstall the valve connected by welding, so its use is usually limited to long-term reliable operation, or occasions where the use conditions are severe and the temperature is high. Such as thermal power stations, nuclear power projects, ethylene projects on the pipeline.
2) The fully welded ball valve is welded by steel pipe. The ball pad is made of reinforced Teflon. The valve stem adopts explosion-proof design. Temperature range: -29-180℃. All-welded ball valves are widely used in long-distance pipelines such as natural gas, petroleum, heating, chemical and thermal power pipelines.
4.Clamp quick connection ball valve
Using standard electronic polishing, the smooth surface ensures cleanliness with no areas of media accumulation and potential contamination. Quick-release valves make valve opening and maintenance quick and easy, reducing process downtime. It is widely used in process control occasions such as food, pharmacy, cosmetics, clean steam, wine, beverage and biochemical industry.
5. Wafer type connection ball valve
Wafer connection ball valve: a connection form that directly clamps the valve and the two pipes together with bolts, an ultra-thin wafer ball valve.
First determine the nature of the fluid in the pipeline (liquid, gas, or solid; neutral, corrosive, viscous, with suspended particles, vacuum, high pressure, or powder), and then determine the function of the valve, (opening and closing, or needs precisely control the flow, or need to commutate the flow, etc)
From a functional point of view, globe valves are more suitable for pipelines that need to control flow, while butterfly valves and ball valves are more suitable for open/close pipelines because of the straight-through flow channel, small flow resistance, and rapid opening and closing and they can also be used for flow control. Ball valves and plug valves are mostly used for reversing valves because they can have multiple channels.
From the nature of the fluid medium, each valve has its suitable and unsuitable objects. Simply put, gate valve, ball valve, butterfly valve and globe valve: gate valve can be used for high temperature and high pressure, and also can be used for low temperature and low pressure, but it is not suitable for conveying medium with suspended particles such as mud. 
The butterfly valve has a simple structure and can be opened and closed quickly. It is suitable for a variety of media, including media with suspended particles and powdery media, but it is not suitable for high temperature, high pressure and high sealing requirements; the flow adjustment range is small. The ball valve can be used for corrosive medium and low temperature medium because it will not stick; but it is not suitable for high temperature due to the sealing material. The globe valve has a higher temperature resistance level, and the steam valve is mostly a globe valve. Butterfly valves and diaphragm valves are often used for media with high hygiene requirements (food, medicine, etc.).
It is understood that a natural gas high pressure ball valve can withstand a maximum pressure of 500Mpa!PN, nominal pressure (Nominal Pressure), is a way of expressing pressure; it is mainly used in the pressure expression of valve body equipment such as pipelines, pipe fittings, valves, etc.;
Nominal pressure PN is a numerical designation code related to pressure, which is a convenient round integer for reference. All pipeline accessories of the same nominal diameter indicated by the same nominal pressure PN value have the same connection size that is compatible with the end connection type.
The pressure grade PN of the national standard stainless steel ball valve is: 1.6MPa, 2.5MPa, 4.0MPa, 6.4MPa, 10.0MPa, etc. These values correspond to how much pressure it can withstand.
 
ATTENTION: A ball valve can’t control the pressure because the ball valve can only control the flow through the medium!But its function can be used to switch, if you want to adjust the steam size, it is recommended to use a regulating valve!In addition, the valve temperature suitable for the steam pipeline is less than 425 degrees. Basically, you can choose: gate valve, globe valve, metal hard sealing butterfly valve. The normally open and closed valve shut-off valve is mainly used for the valve close to the equipment by the user, because this valve has a better effect on regulating the flow rate. The selection of the valve for the steam pipeline mainly depends on the temperature, pressure, function and installation position. 
 

Yes, but its function can only be used to switch, if you want to adjust the steam size, it is recommended to use a regulating valve!

Ball valves are widely used in petroleum refining, long-distance pipelines, chemical industry, papermaking, pharmaceuticals, water conservancy, electric power, municipal administration, steel and other industries, and occupy a pivotal position in the national economy. It has the action of rotating 90 degrees, and the cock body is a sphere with a circular through hole or channel passing 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 only needs to be rotated 90 degrees and a small torque can be closed tightly. Ball valve is suitable for use as switch and globe valve.
BALL VALVES & AIR TIGHTNESS
Among the valves, only the sealing performance of the ball valve is good, but the sealing performance of the ball valve is one of its main indicators. The sealing structure of the stainless steel ball valve is mainly composed of three parts, one is the sealing between the main and auxiliary valve bodies, which is realized by the sealing adjustment gasket; the other is the sealing between the main valve body and the valve stem, which is formed by the standard “V”-shaped packing Or 0-shaped sealing ring to form the outer sealing structure of the stainless steel ball valve. 
The third is the sealing between the ball and the main and auxiliary valve bodies, which is realized by the sealing seat, which constitutes the main sealing structure of the stainless steel ball valve. The tightness of the main sealing structure affects the working performance of the stainless steel ball valve, and is the key sealing structure in the design and manufacture of the ball valve.
1. Sealing requirements
The sealing index of the stainless steel ball valve is determined by the internal leakage and external leakage requirements. The national standard stipulates that the sealing performance of the non-metallic sealing ball valve shall be performed according to the A level of GB/T13927 “General Valve Pressure Test”, which requires “no visible leakage during the test duration.” “; the aerospace industry standard stipulates that the stainless steel ball valve for ground gas pipeline system “under the air pressure condition of 0.05MPa and 1.1 times the nominal pressure, the pressure should be maintained for 3min, and the internal leakage rate should not be greater than 3 × 10-5Pam3/s (no bubbles escape). ); 
Under the air pressure condition of 1.1 times the nominal pressure, the pressure should be maintained for 3 minutes, and the external leakage rate should not be greater than 1×10-5Pam3/s (no bubbles escape).2. Main factors The main factors affecting the sealing performance of the ball valve are the roughness of the sealing surface and the parameters of spherical roundness.
As we all know, no matter how advanced processing technology is adopted, it is impossible to completely solve the roundness error of the sphere and the microscopic defects of the sealing surface. Therefore, in order to achieve a good sealing effect and ensure the realization of the processing process, it is necessary to determine the appropriate sealing surface roughness. and the value of the sphere roundness parameter. 
The relevant data recommends that the maximum allowable value of the roughness Ra value of the spherical sealing surface is 0.4m; the maximum allowable value of the Ra value of the sealing seat roughness is 0.8m when PTFE is used as the sealing material. The roundness tolerance of the spherical surface is more appropriate according to the 6-level accuracy in annex 2 of GB/T1184.
3. Analysis of the main seal structure
Early ball valves generally used metal materials as sealing structures (also known as hard seals). With the development of engineering plastics technology, especially the emergence of polytetrafluoroethylene, the ball valve sealing structure has an ideal sealing material. The soft sealing forms of the common ball valve main sealing structure include rigid sealing seat, sealing seat with elastic element, PTFE lip sealing seat and combined sealing seat composed of elastic expansion ring and PTFE lip sealing seat, etc. form. The lip-shaped structure of the lip-type sealing seat makes it have better elasticity, which can ensure the pre-compression of the sealing surface and compensate for the pre-compression of the sealing surface in use, which is superior to the rigid structure.
4. How to test the air tightness of the ball valve
(1) Leave the valve half-open. Seal both ends of the ball with flange covers with pipe joints.
(2) Introduce the test medium to one end, and the test medium is clean nitrogen or air. The other end of the pipe fitting is blocked. After the pressure is gradually increased to 5.6bar, the intake valve is closed to stop the intake.
(3) Close the ball valve after turning the ball a few times (operating the drive unit)
(4) Open the pipe joint plug at the other end (the end that does not introduce test gas) to reduce the chamber pressure to atmospheric pressure.
(5) Under the test pressure (5.6bar), the pressure of the intake chamber shall not drop for more than 5min. The pressure gauge used should be grade 0.4 with a range of 10bar.
(6) At the same time, use soapy water to check the external leakage of each connecting flange part and packing part, and there should be no growing bubbles.
(7) Then introduce the test medium from the other end and repeat the above test.
(8) After passing the test, use compressed air to blow off the residual soapy water. Remove the flange covers at both ends, and remove the sealing residues on the sealing surfaces at both ends of the ball valve. If any residues enter the valve holes, they should be removed and scrubbed.

 

SERVICE LIFE OF THE BALL VALVE
The service life of industrial valves is mainly determined by quality, but the rational use and maintenance of daily life are also key factors that cannot be ignored.
Therefore, in general, the factors affecting the service life of valves are:
1) The quality of the valve itself
2) The matching degree between the working conditions of the valve and the type, structure, material and other characteristics of the valve itself
3) Is the valve installed correctly?
4) Whether the valve is regularly maintained and whether the maintenance method is correct.
The quality of the valve itself is related to the raw material, structural design and processing technology of the valve;
At the same time, it is also related to the working conditions used. When selecting a valve, you must choose a valve that suits your own working conditions. This can be achieved by constantly summarizing the special points of your own process and the points that are prone to problems, and more with the valve. supply
As far as imported valves are concerned, the service life of valves of different types and uses is different, and the requirements of enterprises and the guarantee time limit of suppliers are also different. For example, valves used in the nuclear industry generally have a service life of 30 to 40 years. Due to the particularity of nuclear power plants, various countries have stipulated the service life of nuclear power valves.
For example, the United States and Germany are guaranteed 40 years for nuclear power valves, the United Kingdom is 30 years, and Japan It is 30 to 40 years. Others, such as trap control valves, generally have a life span of 5 to 10 years. Of course, there are also recommended scientific service life according to specific working conditions, but there is no unified specification at present. corrosion, it is recommended to replace it after 5 to 6 years of use.
Several common questions about ball valve maintenance
Can ball valves break?
Ball valve is a universal valve widely used in valves. It is used in large quantities and consumes quickly. If it is not maintained and repaired in time, a break will occur!
Can ball valves be repaired?
Most ball valves are designed to be maintenance-free and end up being replaced rather than repaired.
How do you replace a ball valve stem?
1. Clean and inspect the dismantled parts. It is strongly recommended to replace the valve seat and valve cover gasket and other seals with a spare parts package.2. Assemble in the reverse order of disassembly.
3. With the specified torque, cross-lock the flange connecting bolts.
4. Tighten the stem nut with the specified torque.
5. After installing the actuator, input the corresponding signal to drive the valve core to rotate by rotating the valve stem, so that the valve can be opened and closed.
6. If possible, please carry out pressure sealing test and performance test on the valve according to relevant standards before reinstalling the pipeline. 
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