What are ball valves?

What are ball valves?

Ball valves are evolved from cock valves. It has the same 90 degree rotation action, the difference is that the ball valve is a sphere, with a circular through hole or channel through its axis. The ratio of spherical surface to passage should be the same, that is, when the sphere rotates 90 degrees, all spherical surfaces should be present at the inlet and outlet, so as to cut off the flow. Ball valves can be closed tightly with only 90 degrees of rotation and a small moment of rotation. Fully equal inner chamber of the valve body provides a direct passage with little resistance to the medium.
It is generally believed that ball valves are most suitable for direct opening and closing, but recent developments have designed ball valves to throttle and control flow. The main characteristics of the ball valve are compact structure, easy operation and maintenance. It is suitable for general working media such as water, solvent, acid and natural gas. It is also suitable for medium with poor working conditions, such as oxygen, hydrogen peroxide, methane and ethylene. Ball valve body can be integral or combined.

0 famen 9881 0 20160418135639 - What are ball valves?

Standards of ball valves Materials of ball valves Types of ball valves
Uses of ball valves Advantages of Ball Valve Application occasions of ball valves
Application Principles of Ball Valves Installation and maintenance of ball valve Daily Maintenance of Ball Valve

The commonly used ball valve structural characteristics and design standards

Serial number Name Structural characteristics Applicable design standards
One Threaded, socket welding end, whole or split Globe valve 1, runner: no shrinkage or shrinkage
2, the ball bearing method: (a floating type)
3, anti blowout structure
4, if necessary, can be set, anti-static fireproof structure
5, connection: thread, socket welding, butt welding (extended body)
BS 5351-1986
ISO 7121-1986
GB/T 12237-1989
MSS-SP-72-1992
JPI-7S-48-1999
BS 5159-1982
Two Clamping type, body type ball valve Clamp
The rest of the same serial number 1
Three Two pairs of fractional or integral side mounted valve 1, runner: no shrinkage or shrinkage
2, the ball bearing: floating (seat supporting type) or fixed (shaft type)
3, anti blowout structure
4, if necessary, can be set or anti-static fireproof structure
5, connection: flange
Four Or a side mounted integral ball valve 1, channel: all pass through or reducing
2, the ball bearing: floating (seat supporting type) or fixed (shaft type)
3, anti blowout structure
4, the sliding seat or the seal cavity type sphere
5, if necessary, can be set or anti-static fireproof structure
GB/T 12237-1989
Five Trunnion Mounted Ball Valve

 

1, channel: full size
2, ball bearing: (fixed shaft type)
3, the valve body and the valve cover flange connection:
4, connection: flange, welding (RF, RTJ)
5, anti-static, fireproof structure
API 6D-2002
Six A type of ball valve 1, runner: straight, necking
2, the valve body is forged or cast steel
3, screw pressing seat
4, the blow out proof structure
5, connecting thread
GB/T 12237-1989
Seven Two piece ball valve 1, channel: full size or reduced diameter
2, the left and right valve is forged or cast steel
3, with the screw pressing seat
4, the blow out proof structure
5, connecting thread
GB/T 12237-1989
Eight With insulation jacket ball valve 1, channel: full size or reduced diameter
2, the valve body with forged or cast steel
3, the floating ball: PTFE seat
4, the valve stem seal with packing seal, packing pressure and compression plate
5, flange
6, the body part is provided with an insulating jacket
Nine Metal seal coat type pneumatic ball valve 1, channel: full size or reduced diameter
2, valve body, valve cover with chrome molybdenum steel casting
3, flange connection: screw connection
4, flange sealing the sealing ring, the seat is made of metal
5, sealing surface welding hard alloy
6, flange
API 6D-2002
GB/T 12237-1989
API 608-1995
Ten Oil seal type fixed ball valve 1, channel: full size
2, the left and right body and ball adopts cast steel or forged steel
3, the left and right valve sealing ring by O
4, connect the left and right valve connected with bolts
5, the two seat ring are respectively provided with a filling nozzle
6, the stem and the ball by key connection
7, connected with the pipe by welding or flange connection
8, the sealing ring made of polytetrafluoroethylene
API 6D-2002
GB/T 12237-1989
API 608-1995
Eleven The sliding seat floating ball valve 1, channel: full size or reduced diameter
2, the left and right body are forged or cast steel
3, the left and right valve bolts, the sealing gasket seal
4, the left and right valve sealing ring is 5 degrees slope, the seat ring can freely slide in 5 degrees on the inclined plane
5, the valve stem packing seal
6, the valve body is arranged at the bottom of the adjusting screw with packing seal
7, connection: flange connection
GB/T 12237-1989
API 608-1995
Twelve Front seat sealing fixed ball valve 1, channel: full size
2, valve body, valve cover and ball adopts cast steel or forged steel
3, the body.
4, the valve bonnet by bolts
5, the floating valve seat, the sealing surface of PTFE valve seat is provided with a spring seat behind the front shoulder, through calculation, ensure the import valve seat sealing pressure
6, connection: flange connection, welding
API 6D-2002
API 608-1995
Thirteen After the fixed ball valve seat sealing 1, runner: all pass by
2, valve body, valve cover and ball adopts cast steel or forged steel
3, the body.
4, the valve bonnet by bolts
5, the floating valve seat, the sealing surface of PTFE valve seat is provided with a spring seat behind, after the shoulder through calculation, ensuring the outlet end of the valve seat sealing pressure
6, connection: flange or welding
API 6D-2002
API 608-1995
Fourteen Three type fixed ball valve 1, channel: full size
2, in the body, left and right valve, ball adopts cast steel or forged steel
3, in the body, the left valve body and the right valve connected with bolts, gasket
Fixed 4, the ball valve
5, the seat ring is arranged at the back or shoulder disc spring
6, the seat is made of Teflon or metal
7, on the lower stem are respectively provided with a bearing on the valve stem by O ring seal
8, connection: flange connection or welding
API 6D-2002
API 608-1995
Fifteen A fixed ball valve 1, channel: full size
2, valve body, valve cover, ball adopts cast steel or forged steel
3, valve body, valve cover connected with bolts, and ensure the sealing gasket
API 6D-2002
API 608-1995
Sixteen The fully welded ball valve 1, channel: full size
2, the left and the right valve body is made of cast or forged steel
3, the valve assembly, after being tested, the left and right body and then welded together
4, the upper and lower stem fixed sphere
5, on the stem seal with O ring, the lower stem seal gasket and seal welding, the upper and lower stem are respectively provided with a bearing
Behind the 6 seat, and the shoulder is provided with a disk spring, valve seat seal with PTFE or metal
7, connection: flange connection or welding
API 6D-2002
API 608-1995
Seventeen All welded floating ball valve 1, channel: full size or reduced diameter
2, valve body, ball made of steel plate forming. Seat and packing box by turning round steel, forged steel flange
3, the seat ring made of polytetrafluoroethylene
4, with blowout proof stem structure
5, the whole valve assembly debugging qualified, welded as a whole
API 608-1995
Eighteen The screw type lifting rod ball valve 1, channel: full size or reduced diameter
2, the ball type valve.
3, the valve body and the valve cover are connected by bolts
4, valve body, valve cover, sphere, using cast steel or forged steel
5, the seat is made of metal welding hard alloy, contact ball and seat face welding hard alloy
6, the fixed ball
7, the lower part of the valve stem is twisted, the valve stem from the valve seat after the ball down to drive the rotating 90 degrees or 90 degrees rotation pressure to the valve seat
8, connection: flange, welding clamp
API 6D-2002
API 608-1995
Nineteen The guide slot type lifting rod ball valve 1, channel: full size or reduced diameter
2, the ball type valve.
3, the valve body and the valve cover are connected by bolts
4, valve body, valve cover, ball adopts cast steel or forged steel
5, the seat is made of metal welding hard alloy, contact ball and seat face welding hard alloy
6, the fixed ball
7, valve stem is provided with a S shaped guide groove, the guide pin and guide groove, the stem down from the seat and then drives the ball rotating 90 degrees or 90 degrees rotation pressure to the valve seat
8, connection: flange, welding
API 6D-2002
API 608-1995

Materials:

  • Brass
  • Copper
  • Cast Iron
  • Bronze
  • Ductile iron
  • Stainless steel
  • Metal alloys
  • Plastic
  • Ceramic etc.

Parts of ball valves:

  1. End piece
  2. Body
  3. Ball
  4. Cover ring
  5. Body seals
  6. Seats
  7. Bolt & nuts

Styles of ball valves:
Ball valves have three general body styles. They are as follows:

  • Split bodyball valves2 - What are ball valves?
    • One-piece
    • Two-piece
    • Three-piece
    • Flanged body
  • Top entry
  • Welded

Each of these body styles have specific advantages depending upon the requirements of the given application.

Types of ball valves:

Functional classification

  1. Bypass valves: ball valves are generally open in static water, so the Bypass valves should be installed first, i.e. both sides are filled with water.
  2. Air valves: when filling water, the air is removed and the buoy closes itself; when draining water, the buoy drops by itself with supplementary air.
  3. Pressure relief valve: When opening and closing the valve, remove the pressure water between the valve and the sealing cover, so as not to wear the sealing cover;
  4. Sewage discharge valve: discharging the sewage from the lower part of the spherical shell.

Transmission classification

  1. Pneumatic Ball Valve
  2. Electric Ball Valve
  3. Hydraulic Ball Valve
  4. Pneumatic and Hydraulic Ball Valve
  5. Electro-hydraulic Ball Valve
  6. Turbine Drive Ball Valve

Ball valves can be divided into:

1. Floating ball valve
The sphere is floating. Under the action of medium pressure, the sphere can produce a certain displacement and press tightly on the sealing surface of the outlet to ensure the sealing of the outlet.
Floating ball valve has simple structure and good sealing performance, but the load of working medium on the ball is all passed 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. This structure is widely used in low and medium pressure ball valves.
2. Fixed Ball Valve
The sphere is fixed and does not move under pressure. Fixed ball valves are equipped with floating seats. After medium pressure, the seats move, so that the sealing ring is pressed on the ball to ensure sealing. Usually, bearings are installed on the upper and lower axles of the sphere, and the operation torque is small. It is suitable for high pressure and large caliber valves.
In order to reduce the operating torque of the ball valve and increase the reliability of the sealing, oil-sealed ball valves have appeared in recent years. They not only inject special lubricating oil between the sealing surfaces to form a layer of oil film, which enhances the sealing performance, but also reduces the operating torque. They are more suitable for high-pressure and large-caliber ball valves.
3. Elastic ball valve
The sphere is elastic. The ball and seat seals are made of metal materials, and the specific pressure of the seals is very high. The pressure of the medium itself can not meet the requirements of the seals, so the external force must be applied. This valve is suitable for high temperature and high pressure media.
Elastic sphere is an elastic groove opened at the lower end of the sphere wall to obtain elasticity. When closing the passage, the wedge head of the valve stem is used to make the sphere open and the valve seat press to seal. The wedge head is loosened before the ball is rotated, and the ball is restored 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.
Ball valves can be divided into straight-through type, three-way type and right-angle type according to their channel position. The latter two kinds of ball valves are used to distribute the medium and change the flow direction of the medium.

Characteristics and Advantages of Fixed Ball Valve

A ball valve with a fixed shaft is called a fixed ball valve. Fixed ball valves are mainly used for high pressure large caliber. According to the different installation of seat seal ring, fixed ball valve can have two kinds of structure: the front sealing seat of the sphere and the back sealing seat of the sphere.

I. Characteristics of Fixed Ball Valve: Fixed Ball Valve, Fixed Ball Valve, Fixed Ball Valve, Fixed Ball Valve, Fixed Ball Valve, Fixed Ball Valve.

  1. Dual blocking and discharge function: Fixed ball valve adopts spring pre-tightening floating seat. Whether the valve is in full open or closed state, the upper and lower side seats block the flow, and the retained material in the valve body is discharged through the discharge valve.
  2. Automatic pressure relief function: When the abnormal pressure rise is caused by the increase of the temperature of the retaining medium in the body cavity of the valve, it is not necessary to pass the safety valve, but it can be relieved automatically only by the function of the valve seat, which is very important to ensure the safety of the valve when transporting liquid medium.
  3. Fire-proof safety structure: Valves have fire-proof safety function, and they are designed and manufactured in accordance with API 607 and API 6FA specifications.

2. Advantages of Fixed Ball Valve:

  1. Sealing emergency grease injection rescue: due to foreign bodies in the media or fire caused by accidental failure of valve seat seal, grease injection valve provides a rapid connection with grease injection gun, the import pump can easily and quickly inject the grease into the seating part of the valve seat to alleviate leakage.
  2. Reliable stem seal and low operating moment: In addition to standard sealing rings, O-ring is also installed on packing cover, double sealing ensures the reliability of stem seal; the addition of graphite filler and sealing grease injection reduces the leakage of stem after fire to the lowest level. Stem sliding bearings and thrust bearings make the valve easy to operate.
  3. Full-diameter or shrinkage: Full-diameter or shrinkage structure can be selected according to need. The flow orifice of full-diameter valve is the same as the inner diameter of pipeline, which is convenient for pipeline cleaning.
  4. The valve stem can be lengthened: according to the need of installation or operation, the valve stem can be lengthened. Lengthened rod ball valve is especially suitable for buried pipeline laying occasions such as city gas. Lengthened stem size is determined according to customer needs.
  5. Flexible operation: The use of seat and stem bearings with small friction coefficient and good self-lubrication greatly reduces the operating torque of the valve. Therefore, the valve can be operated flexibly for a long time even in the absence of sealing grease.

Salient features of ball valve: 

Ball valves have certain characteristics which make them superior to other valves. They are as follows:

  • Positive shut off
  • Quick in action
  • No lubrication
  • Visual on/off indication
  • Compact design
  • Longer life
  • Corrosion resistant
  • Low pressure drop
  • Simplicity

Uses of ball valves:
The ball valve is mainly used to cut, distribute and change the flow direction of the medium on the pipeline. The ball valve designed as a V-shaped opening also has a good flow regulation function.
The ball valve not only has a simple structure and good sealing performance, but also has a small volume, a light weight, a small material consumption, a small installation size, a small driving torque, a simple operation, and an easy opening and closing in a certain nominal passage range. One of the fastest growing valve varieties in more than a decade. Especially in the developed countries of the United States, Japan, Germany, France, Italy, West, Britain and other industries, the use of ball valves is very extensive, the variety and quantity of use continue to expand, and to high temperature, high pressure, large mouth, high sealing, long The life, excellent adjustment performance and the development of a multi-valve direction have achieved a high level of reliability and other performance indicators, and have partially replaced gate valves, globe valves, and regulating valves.
With the technological advancement of ball valves, there will be a wider range of applications in the foreseeable short-term, especially on oil and gas pipelines, on refinery crackers and in the nuclear industry. In addition, in the large and medium-sized, medium and low pressure areas of other industries, ball valves will also become one of the leading valve types.

The various uses of ball valves are as follows:

  • They are used in situations where tight shut-off is required.
  • They are wide duty pipe valves.
  • They are able to transfer liquids with suspended solids (slurries), gases, liquids.
  • They provide superior ease of operation.
  • They can maintain and regulate high volume, high pressure and high temperature flow.
  • The ball valve body design permits inspection as well as repair of seats and seals without removing the valves’ body from the line.
  • Firesafe ball valves provide effective shut-off during or following a fire or when exposed to excessive temperatures.
  • Ball valves are used in gas and oil pipelines.

Advantages of Ball Valve

  1. It has the lowest flow resistance (actually zero).
  2. It can be used reliably in corrosive media and low boiling point liquids because it can not be stuck at work (without lubricants).
  3. Full sealing can be achieved in a wide range of pressure and temperature.
  4. Quick start-up and shut-down can be realized, and the start-up and shut-down time of some structures is only 0.05-0.1s, so as to ensure that they can be used in the automation system of the test bed. When the valve is opened and closed quickly, there is no impact in operation.
  5. The spherical closure can be positioned automatically in position.
  6. The working medium is reliable in sealing on both sides.
  7. When fully open and fully closed, the sealing surface of the sphere and 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. It can be considered as the most reasonable valve structure for cryogenic medium system.
  9. The valve body is symmetrical, especially when welded, and can well withstand the stress from the pipeline.
  10. The closing part can withstand the high pressure difference when closing.
  11. The ball valve with fully welded body can be buried directly underground, so that the inner 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 natural gas pipelines.
  12. Because of the advantages mentioned above, the ball valve has a wide range of applications. The ball valve can be applied to:
  13. The nominal menstruation ranges from 8 mm to 1200 mm.
  14. The nominal pressure ranges from vacuum to 42 MPa.
  15. The working temperature ranges from – 204 C to 815 C.

Sealability of ball valves

PTFE is the most important seating ring material for ball valves. It is inert to almost all chemical substances, and has the comprehensive characteristics of small friction coefficient, stable performance, not easy to aging, wide temperature application range and excellent sealing performance. However, the physical properties of PTFE, including high expansion coefficient, sensitivity to cold flow and poor heat conductivity, require that the design of seat seals must be based on these characteristics. Plastic materials for seat seals also include filled PTFE, nylon and many other materials. However, when the sealing material hardens, the reliability of the seal will be destroyed, especially in the case of low pressure drop. In addition, synthetic rubber such as butadiene-green rubber can also be used as seat sealing material, but its medium and temperature range of use are limited. In addition, if the medium is not lubricated, the use of synthetic rubber is easy to block the sphere.
In order to meet the requirements of industrial applications such as high temperature, high pressure, strong erosion and long service life, metal sealed ball valves have been greatly developed in recent decades. Especially in developed countries, such as the United States, Italy, Germany, Spain, the Netherlands and so on, the structure of ball valves has been constantly improved. Full-welded body direct-buried ball valves, lifting ball valves, ball valves are more and more widely used in long-distance pipelines, refineries and other industrial fields. Large caliber (3050mm), high pressure (70MPa) and wide temperature range (-196-815 C) have emerged. Ball valve, so that the ball valve technology to a new level.

Design and Manufacture of Ball Valve

Because of the application of computer aided design (CAD), computer aided manufacturing (CAM) and flexible manufacturing system (FMS) in valve industry, the design and manufacture of ball valves have reached a new level. It not only completely innovates the design and calculation method of valves, reduces the heavy repetitive routine design work of professional technicians, makes technicians have more energy to improve and improve product performance and new product development, shortens the research and development cycle of new products and improves labor productivity in an all-round way, but also in the development process of lifting rod metal seal ball valves, due to CAD. / In the application of CAM, the screw flat of the valve stem, which is designed by computer aided design and manufactured by computer aided numerical control machine tool, makes the metal sealed ball valve free from any abrasion and wear in the opening and closing process, thus greatly improving the sealing performance and service life of the ball valve. When the ball valve is fully opened, the flow resistance is very small, almost equal to zero, so the equal diameter ball valve is widely used in oil and gas pipelines, because it is easy to clean pipelines. Because the ball body of the ball valve has wiping property in the opening and closing process, most of the ball valves can be used in the medium with suspended solid particles, according to the material of the sealing ring, it can also be used in powder and granular media.

Application occasions of ball valves

Because ball valves usually use rubber, nylon and polytetrafluoroethylene (PTFE) as seating ring materials, their operating temperature is limited by seating ring materials. The cut-off effect of ball valves is achieved by pressing metal spheres under the action of medium between plastic seats (floating ball valves). Under certain contact pressure, elastic-plastic deformation occurs in some parts of the seat seal ring. This deformation can compensate the manufacturing accuracy and surface roughness of the sphere and ensure the sealing performance of the ball valve.
Because the seating ring of the ball valve is usually made of plastic, the fire resistance and fire resistance of the ball valve should be considered in the selection of the structure and performance of the ball valve, especially in the petroleum, chemical and metallurgical sectors, the use of the ball valve in the equipment and pipeline systems of flammable and explosive media, and more attention should be paid to fire resistance and fire resistance.
Usually, ball valves are recommended in pipeline systems with two-position regulation, strict sealing performance, mud, abrasion, shrinkage passage, quick opening and closing action (1/4 turn-on and closing), high pressure cut-off (large pressure difference), low noise, cavitation and gasification, small leakage to the atmosphere, small operating moment and small fluid resistance.
Ball valves are also suitable for piping systems with light structure, low pressure cut-off (low pressure difference) and corrosive media.
Ball valves can also be used in cryogenic (cryogenic) devices and pipeline systems.
In the oxygen pipeline system of metallurgical industry, it is necessary to use ball valves after strict degreasing treatment.
When the main pipelines in oil and gas pipelines need to be buried underground, full-diameter welded ball valves should be used.
When adjusting performance is required, ball valves with special V-shaped openings should be selected.
In petroleum, petrochemical, chemical, power and urban construction, metal-to-metal sealed ball valves can be selected for pipeline systems operating at temperatures above 200 degrees Celsius.

Application Principles of Ball Valves

For the main pipelines for oil and natural gas transportation, which need to be cleaned and buried underground, the ball valves with all-through and all-welded structure are selected; for those buried on the ground, the ball valves with all-through welding connection or flange connection are selected; for branch pipes, the ball valves with flange connection or welding connection and full-through or shrinkage diameter are selected.
Flanged ball valves are selected for the transportation pipeline and storage equipment of finished oil.
Floating ball valves connected by flanges and internal threads are selected for city gas and natural gas pipelines.
In the oxygen pipeline system of metallurgical system, fixed ball valves connected by flanges after strict degreasing treatment should be selected.
Low temperature ball valves with valve caps should be selected for piping systems and devices of cryogenic media.
In the pipeline system of FCC unit of refinery unit, lifting rod ball valve can be selected.
All stainless steel ball valves made of austenitic stainless steel and with PTFE as seat seal ring should be selected in the equipment of corrosive medium such as acid and alkali in chemical system and pipeline system.
Metal-to-metal sealed ball valves can be used in pipeline systems or devices of metallurgical systems, power systems, petrochemical plants and high-temperature media in urban heating systems.
When flow regulation is needed, adjusting ball valves with V-shaped openings driven by worm gears or worms, pneumatic or electric, can be selected.

First, the installation of ball valves

Ball valve installation should notice

Preparing for installation 1, Globe valve Before and after the pipeline is ready. Before and after the pipeline should be coaxial, two flange sealing surface should be parallel. Pipeline should be able to withstand the weight of the ball valve, or pipe must be equipped with appropriate support.
2, the purge valve before and after the pipeline clean, clear out the oil pipeline, welding slag, and all other impurities.
3, the check valve of the signs, identify the valve intact. Fully open the valve fully closed several times confirmed that it is working.
4, remove the valve protection on both ends of flange pieces.
5, check the valve clearance hole may have dirt, then clean the valve hole. Between the seat and the ball even if only tiny particles of foreign matter may damage the valve seat sealing surface .
install 1, the valve installed on the pipeline. Any end of the valve can be installed in the upstream end.Any position driven by the valve handle can be installed in the pipeline. But with a gear box or pneumatic valve drive should be installed upright, that is installed in horizontal pipelines, and the drive is in the pipeline at the top.
2, the valve between the flange and pipe flange design by piping installed gasket.
3 flange bolts need to symmetry successive evenly tightened.
4, connect the pneumatic line (pneumatic drive).
After installation check 1, start operating the drive, closed ball several times, should be flexible without Zhise, confirmed that it is working.
2, according to the design requirements of the pipeline with the valve on the pipe flange between the combined sealing surface for inspection.

Two, ball valve repair

We must first identify the valve on the downstream pipeline pressure has indeed dropped after attempting to disassemble the operation.

Must be careful to prevent damage to parts of the sealing surface 2, decomposition and re assembly, especially non-metallic parts, remove the O ring when using special tool.

Bolts on the flange assembly to be symmetrical gradually evenly tighten.

Cleaning agents should be in a rubber ball, plastic parts, metal parts and the working medium (such as gas) are compatible. Working medium for the gas, the gas can be used (GB484-89) to clean metal parts. Pure water or alcohol cleaning with non metal parts.

Individual components can be decomposed down cleaned by immersion method. The metal non metal still did not break down the left can be used to clean fine clean silk impregnated with cleaning agents (to prevent adhesion of fiber loss on the part) scrub. To remove all the adhesive on the wall of the grease, dirt, rubber product, dust cleaning.

Non-metallic parts should be cleaned immediately removed from the cleaning agent, not a long time soaking.

Need to be cleaned by washing the wall after volatile cleaning agent (cleaning agent can not dip silk rub) for assembly, but not for a long time on hold, otherwise it will rust, dust pollution.

Before the new parts in the assembly can be cleaned.

The use of grease lubrication. Greases are compatible with the ball of metal materials, rubber parts, plastic parts and the working medium. Working medium for the gas, 221 can be used such as special grease. Seals installed in the groove on the surface coated with a thin layer of grease on the rubber seal coated with a thin layer of grease, coated with a thin layer of grease on the sealing surface and the friction surface of the stem.

The assembly should have metal fragments, fiber, fat is not allowed (except the requirement to use) dust and other impurities, foreign matter contamination, adhesion or remain on the surface or in part into the cavity.

Daily Maintenance of Ball Valve

With a longer service life and maintenance-free period, it will depend on the following factors: normal working conditions, maintaining a harmonious temperature/pressure ratio, and reasonable corrosion data.
When the ball valve is closed, there is still pressure fluid inside the valve body.
Before maintenance: release pipeline pressure and keep valve in open position; disconnect power or gas source; disconnect actuator from bracket
Before disassembly and decomposition operation can be carried out, it must be ascertained that the upstream and downstream pipes of the ball valve have been removed pressure.
When decomposing and reassembling, care must be taken to prevent damage to the sealing surface of parts, especially non-metallic parts. Special tools should be used when removing O-rings.
Bolts on flanges must be tightened symmetrically, step by step and evenly during assembly.
Cleaning agent should be compatible with rubber parts, plastic parts, metal parts and working media (such as gas) in ball valves. When the working medium is gas, the metal parts can be cleaned with gasoline (GB484-89). Cleaning of non-metallic parts with pure water or alcohol
Non-metallic parts should be removed from the cleaning agent immediately after cleaning, and should not be immersed for a long time.
After cleaning, it needs to be assembled after the wall cleaning agent evaporates (can be wiped with silk cloth without soaking detergent), but it should not be put on hold for a long time, otherwise it will rust and be polluted by dust.
New parts also need to be cleaned before assembly.
Metal debris, fibers, grease (except for specified use) dust and other impurities, foreign bodies, etc. shall not be allowed to contaminate, adhere to or remain on the surface of the parts or enter the inner cavity during assembly. If micro leakage occurs at the filler, the stem nut shall be locked again.
Note: Do not lock too tightly, usually lock 1/4 to 1 turn again, the leak will stop.
A) Dismantling
Make the valve in the half-open position, flush and remove the dangerous substances that may exist inside and outside the valve body.
Close the ball valve, remove the connecting bolts and nuts on both flanges, and then remove the valve completely from the pipeline.
Disassemble the driving device in sequence – actuator, connecting bracket, anti-loosening washer, stem nut, butterfly spring, Gnan, wear-resistant plate, stem packing.
Remove the cover connecting bolts and nuts, separate the cover from the body, and remove the cover washer.
Confirm that the ball is in the “off” position, which makes it easier to remove it from the valve body and then from the seat.
The stem is pushed downward from the hole in the body until it is completely removed, and then the O-ring and the packing under the stem are removed.
Note: Please operate cautiously to avoid scratching the stem surface and the sealing part of the body packing box.
B) Reassembly
Clean and inspect the parts and remove them. It is strongly recommended to replace the seats and cover gaskets of spare parts packages.
Assemble in reverse order of disassembly.
Cross-lock flange bolts with specified torque.
Lock the stem nut with specified torque.
After the actuator is installed, the corresponding signal is input to drive the spool to rotate through the rotating stem to make the valve open and close.
If possible, test the pressure seal and performance of the valve according to the relevant standards before installing the pipeline.

Source: China Ball Valves Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.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.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

Please notice that you might be interested in the other technical articles we’ve published:

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  • What are valves

  • Nine Anti-Corrosion Measures of Valves

  • The Selection of Control Valve

  • Operation and Maintenance Manuals for Gate Valves

  • When the control valves are used in liquid service

  • Choosing Valves Based on Industry Characteristics

  • Designs and Uses of Ball Valves for Submarine Pipelines

  • What is a ball valve

  • How to choose valves

Source:

  • https://www.bhpipe.com/what-is-a-ball-valve.html
Summary
astm a182 f51 full port floating ball valve rf class 300 dn25 - What are ball valves?
Article Name
What are ball valves
Description
Ball valves are evolved from cock valves. It has the same 90 degree rotation action, the difference is that the ball valve is a sphere, with a circular through hole or channel through its axis.
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Publisher Name
www.steeljrv.com
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