What matters should pay attention for the ball valve installation and maintenance?

Ball valve has a small fluid resistance, the drag coefficient equal to the same length of the barrel; simple structure, small size, light weight; compact and reliable valve sealing surface material widely used plastic, sealing, and has also been widely used in the vacuum system ; easy to operate, opening and closing rapidly, fully closed as long as the rotation 90 °, easy remote control from fully open to; easy maintenance, simple ball valve, seals are generally activities, the removal replacement is more convenient; in full or When fully closed, the ball and seat sealing surface and the dielectric isolation, through the media, will not cause erosion of the valve sealing surface. Ball valve installation and maintenance should note the following:

1) Ball valve handle rotation to leave the position.
2) Cannot be used as a throttle.
3) Ball valve belt transmission mechanism should be installed upright. Ball valve works by the rotary valve love to make the ball valve flow or occlusion. Ball valve switch light, ball valve small size, can be made into a large caliber, reliable sealing, simple structure, easy maintenance, with the spherical sealing surface often in the closed state, the media cannot easily be eroded, in various sectors has been widely used. A ball valve in the pipeline is mainly used for cutting, distribution and changes the direction of media flow. Metal seat ball valve is a relatively new type of ball valve type, it has its own unique structure some advantages, such as switches without friction, seal easy to wear, small opening and closing torque. This reduces the actuator with the specifications. With multi-turn actuators can be realized on media regulation and tight cut. Widely used in urban water supply and drainage in petrochemical demanding cutting conditions.

Should you want to know more about ball valve, such as trunnion ball valves, please visit www.reliavalve.com or email us via sales@reliavalve.com.

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from:What matters should pay attention for the ball valve installation and maintenance?

What is the front seal and back seal for the ball valve?

In addition cinder ball valve, spray ball valve pulverized coal, others, like the floating ball valve,trunnion mounted ball valve, V-type ball valve, eccentric semi-ball valve, three way ball valve, which has two seats, the first seal means that the inlet end seat acts as a seal, the back seal means that seal the outlet end of the seat from the actual principle is very simple, which is to seat sealing O-ring sealing surface on the outside of the seat within the differences and. There is also a two-way sealed DIB structure; its principle is to increase the O-ring, the inner circle within the valve seat ring, the outer ring outside the seat.

After the back seat seal trunnion  ball valve, the fluid pressure on the ball and seat effective force is small, therefore, the bearing load and friction torque are small, which gives the drive and bearing design, especially for low friction coefficient with self-lubricating properties, but the choice of compressive strength is low, there is a tendency of cold PTFE sliding bearings to provide a convenient, the disadvantage is that the valve seat seal: To ensure da> dw, if not reduce the valve channel cross-sectional area, it is necessary to increase the size of the ball and the body's structure.

For the first seal, the back sealed on both sides of trunnion mounted ball valve, the advantage of reliable sealing performance, low bearing loads, so it is suitable for sealing particularly demanding situations, when the ball valve body cavity pressure P2 abnormally elevated, it cannot automatic pressure relief, therefore, when using double sealed ball transporting liquefied gas, the need to coat the body of a small safety valve.

When the fluid pressure PN≥16MPa, valve size DN = 80-200mm, the general use of the back seat seal, for delivery pressure PN≤10MPa corrosive media and gases, as well as valve size larger occasions, should be adopted valve seat before sealing, the sealing requirements are particularly stringent, or more dangerous media, we recommend using double-sided seal valve, in order to increase the sealing performance, reduce friction and wear seat, extend its life and to prevent the ball valve use due to damage caused by accident seat, oil seal structure can be added in the seat, but it must be noted that only the auxiliary oil seal from the seal, or as a temporary emergency measure, oil seal structure used for larger diameter and conveying gas trunnion mounted ball valve medium.

Should you want to know more about ball valve from Reliable China  valve manufacturer, please visit www.reliavalve.com or email us via sales@reliavalve.com.

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 This is from:What is the front seal and back seal for the ball valve?

What is the ball valve sealing performance?

In order to achieve zero leakage sealing ball valve inside and outside, to save energy, protect the environment and improve work efficiency, valve must have a reliable sealing performance, ball valve sealing performance is the ball valve part of the sealing ability to prevent media leaks, it is under test conditions rated valve internal and external leaks. Contact points with the department, filler stem and the stuffing of the main parts of the opening and closing ball valve sealing member and the ball valve seat sealing surface between the body and bonnet connection which is called before a leak within the leak, also is commonly known as a bad relationship, it will affect the ability of the ball valve cut off media, for the cut-off valve, the internal leakage is not allowed, Leakage after the two called the leak, that media leaks from the valve to the valve outside , Leakage will result in material losses, environmental pollution can also cause serious accidents. The sealing performance of the valve is an important indicator of valve function and quality.

The ball valve leakage problem a serious threat to the normal operation of the device, and the operation of the ball valve and very difficult to find whether there is leakage, the survey results show that the use of a variety of petrochemical enterprises each with varying degrees of valve leakage problems exist, the reason there is a ball valve plate, seat sealing surface material does not meet the requirements, processing accuracy is not enough, gate valve plate, seat wedge angle does not match, the sealing surface varies in width, fit is poor, the shutter is not in place, and other factors related death. Such as: For flange cast steel gate valve, the sealing surface material code should refer to the hardness of sealing a relatively soft sealing surface material, other seal face materials shall be at least apparently corresponding carbide, and in fact there are only one valve sealing surface surfacing hard alloy and the other sealing surface of the bulk material is carbon steel, and put into use not long to occur due to wear and tear in the drain phenomenon. Another example of a piping system selected folder-off valve, seat material PTFE, the use conditions, the demand is not high, it is normal temperature and pressure, but found a large number of in trial run The ball valve closed lax, leakage severe that they cannot normally use, and finally had to replace a valve, removed examination found that the closed state of the ball valve plate and seat a great gap, even light. Analysis of the reasons may include the following: the structural design manufacture and assembly of precision unreasonable or ball valve seal pair fail to meet requirements; failure to require the construction and installation of the ball valve so that it put too much force; the construction process in welding slag, sand, metal shavings and other debris from entering the ball valve chamber, the sealing effect is affected. In fact, more practical, it is the most fundamental reason is that in the valve manufacture, transportation or installation process fails certain standard requirements to do so.

The explosive, toxic or radioactive medium, leakage is allowed, and therefore, the ball valve must have a reliable sealing performance.

Should you want to know more about ball valve from Reliable China valve manufacturer, please visit www.reliavalve.com or email us via sales@reliavalve.com.

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This is from:What is the ball valve sealing performance?

How to solve the low temperature ball valve(cryogenic ball valve) stuck pull fixed the problem?

Why cryogenic ball valves prone to pull stuck motionless phenomenon, how should it be solved?

A: The low temperature ball valve(cryogenic ball valve) installed at room temperature, work at low temperatures large temperature range. If the design, improper installation, it is prone to heat stress or strain. At the same time, the ball valve is in the normal operating portion, circulation portion is low. To reduce cold damage, stem often do very long, it is easy to be deformed and stuck. Cryogenic ball valves(low temperature ball valves) are often rotated at room temperature flexibility at low temperatures is very tight, and even open. Valve stuck at low temperatures the main reasons are:
1)The installation, low temperature ball valve(cryogenic ball valve) and pipeline configuration unreasonable generate prestressing; or poor pipe cold compensation, at a low temperature ball valve(cryogenic ball valve) position change; or lack valve stent deformation at low temperature; or ball fixed properly, cold box at a low temperature deformation The influence of concentricity with the valve stem.
2)In the design, because of the different stem and the low temperature ball valve(cryogenic ball valve) sleeve material, the linear expansion coefficient is different. Usually the stem stainless steel, linear expansion coefficient of 1.73 × 10-6 ℃ -1; brass sleeve, linear expansion coefficient of 19.9 × 10-6 ℃ -1, i.e., greater than the contraction brass stainless steel, low temperatures may the threaded bite. Especially when using fine thread, threaded a temperature range of large and small thread gap, the phenomenon is more prone to bite.
3)In the operation, due to the low temperature heating is not complete at the ball, or valve packing at the water, causing freeze, or at room temperature, the valve is closed tight at low temperatures, making threaded chewed like.
To prevent hypothermia valve stuck phenomenon, the design should be broad trapezoidal screw threads; there should be a firm stand in the valve at the installation to prevent the valve with the stem pipe displacement and bending. Ball and low temperature cold box can be elastically fixed connection to prevent deformation of the stem and the body different heart; during the cold bare, to check and adjust the cryogenic valve installation in the cold state, when it was found jammed valve cooling When the phenomenon, adjustable valve mounting flange on the cylinder housing, so that the switch easily.
In operation, before the start of the heating should be complete, close the low temperature ball valve (cryogenic ball valve) when the principle of not leak, do not use excessive force.

Should you want to know more about butterfly valve from Reliable China valve manufacturer, please visit www.reliavalve.com or email us via sales@reliavalve.com.

This is from:How to solve the low temperature ball valve(cryogenic ball valve) stuck pull fixed the problem?