Ⅰ. Check that the pneumatic ball valve is in the full open position

After grease injection, check whether the ball port of the valve lines up with the plane of the inner cavity of the valve seat. If there is any difference, adjust the open limit bolt on the actuator to ensure that the valve is fully open. Otherwise, it is unable to judge whether the valve is fully open once the pneumatic ball valve is assembled.

Ⅱ. Unable to inject grease into the pneumatic ball valve

1. When the valve shaft (rod) is greased, the sealing pressure in the pneumatic ball valve shaft (rod) shall not exceed 20.68mpa. Once it exceeds, check whether the grease gun is faulty and whether the outlet valve at the grease outlet of the grease gun is opened.

2. If there is no grease gun failure, check whether the grease nozzle is blocked, that is, slowly unscrew the grease nozzle and install it at the grease outlet hole of the grease gun. Observe whether the grease nozzle can discharge grease by injecting grease into the grease nozzle. If it does not discharge grease, it indicates that the one-way valve in the grease nozzle has fault, and the grease nozzle should be replaced.

If the grease injection nozzle can discharge grease, check the one-way valve located in the grease injection hole at downstream side of the grease injection nozzle (generally, this one-way valve is installed in the imported valve grease injection hole ), and screw it out with special tools for inspection. Any blockage such as raw material belt shall be removed, and the valve shall be replaced if there is serious fault. If it is still unable to inject grease, it shall be reported to the professional engineer and on-site supervisor for on-site solution by the manufacturer.

Ⅲ. Uneven grease injection from grease injection hole of pneumatic ball valve

After the grease injection of pneumatic ball valve, the blocking may occur in the valve seat sealing grease injection pipe, resulting in uneven or no grease discharge from the grease injection hole of the valve seat. This situation requires a 15°~ 25° turn from the fully open position. Then look into the grease outlet hole of the valve seat, gently dredge it with a soft tool, and continue to observe the grease injection.

Special attention shall be paid to the fact that grease shall not be injected during the rotation of the pneumatic ball valve to avoid damaging the seat seal. Generally, there are 4 nozzle’s grease injection at each side of the ball valve are even, while 2 are relatively uneven.

Our company focuses on manufacturing wedge gate valve, pipeline gate valve, floating ball valve, fixed ball valve, top mounted ball valve, stop valve, swing check valve, double plate check valve and forged valve. If you have any needs, please feel free to consult us.

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• 1 It is necessary to find out that the upstream and downstream pipes of the ball valve have been depressurized before disassembling.
• 2. During disassembly and reassembly, care must be taken to prevent damage to the sealing surface of parts, especially non-metallic parts. Special tools should be used when taking out the O-ring.
• 3. During assembly, the bolts on the ball valve flange must be tightened symmetrically, step by step and evenly.
• 4. The non-metallic parts of the ball valve shall be taken out of the cleaning agent immediately after cleaning and shall not be soaked for a long time.
• 5. After cleaning, it needs to be assembled after the cleaning agent of the washed wall volatilizes (it can be wiped by the silk cloth without cleaning agent), but it can not be used for a long time, otherwise, it will rust and be polluted by dust.
• 6. New parts of ball valve shall be cleaned before assembly.
• 7. Use grease for lubrication. The grease shall be compatible with metal materials, rubber parts, plastic parts and working media of ball valve. When the working medium is gas, for example, te221 grease can be used. Apply a thin layer of grease on the surface of the installation groove of the seal, rubber seal and the sealing and friction surfaces of the valve rod.
• 8. When assembling the ball valve, it is not allowed to contaminate, adhere to or stay on the surface of the part or enter the inner cavity with metal chips, fibres, grease (except for the specified ones) and other impurities and foreign matters.

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Stanless steel ball valves suppliers generally remind users to pay attention to the following elements in order to make the ball valve function stable and have long life.

• 1. Before operation, water should be used to clean the pipeline and the part of the valve body overflow in order to prevent residual iron chips and other debris from entering the valve body cavity.
• 2. In the closed state, the local media in the valve body of stainless steel ball valve remains and it also bears certain pressure. Before repairing the ball valve, the shutoff valve in front of the ball valve should be closed, the ball valve in need of repairing should be opened, and the internal pressure of the valve body should be fully released. If it is an electric ball valve or a pneumatic ball valve, it should first disconnect the power supply and air source.
• 3. Ordinary soft-sealed ball valves are made of PTFE as sealing material, and the sealing surface of hard-sealed ball valves is made of metal surfacing. If the pipe ball valve needs to be cleaned, caution should be taken to avoid damage to the sealing ring and leakage when it is disassembled.
• 4. When the ball valve is disassembled and assembled, the bolts and nuts on the flange should be fixed first, then all nuts should be tightened slightly, and finally firmly fixed. If a single nut is fixed forcibly first and then other nuts are fixed, the gasket surface will be damaged or cracked due to the uneven receipt between the flanges, which will lead to leakage of the butt media of the valve flange.
• 5. If the valve is cleaned, the solvent used must not conflict with the parts to be cleaned and corrode them. If it is a special ball valve for gas, gasoline can be used for cleaning. Other parts can be washed with medium water. When cleaning, we should completely clean the residual dust, oil and other attachments. If it cannot be washed with clean water, it can be cleaned with alcohol and other cleaning agents without damaging the valve body and parts. After the cleaning is completed, install it after the cleaning agent evaporates completely.
• 6. If a slight leak is found in the packing during operation, the stem nut can be slightly hastened until the leak stops. If it does not work, keep tightening.
• 7. Long-term open storage will lead to corrosion of the valve body and components, which can not be used properly. Ball valves should be rainproof, waterproof, moisture-proof and tightly covered with flange caps. Valves stored for more than 12 months should be tested from scratch to ensure functional stability.

Zeco Value is a professional stainless steel ball valves manufacturer and provides you with high quality stainless steel ball valves. For more information of stainless steel ball valve price, please contact us.

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I. Advantages and disadvantages of ball valve

1. 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 can not be stuck during operation (when there is no lubricant);
• ③ In a large range of pressure and temperature, it can achieve complete sealing;
• ④ It can realize quick opening and closing, and the opening and closing time of some structures are 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 shall be sealed reliably on both sides;
• ⑦ Qhen 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 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.

2. 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 the 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 not used at 120 ℃.
• ② Its regulating performance is worse than that of gate valve, especially pneumatic valve (or electric valve).

II. Application scope of ball valve:

Due to the ball valve working principle, it is widely used in petroleum refining, long-distance pipeline, chemical industry, papermaking, pharmaceutical industry, water conservancy, electric power, municipal administration, steel and other industries.

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1. Electric ball valves should be stored in dry and ventilated rooms, and both ends of the passage should be blocked.

2. Electric ball valves stored for a long time should be inspected regularly to remove dirt and coated with rust-proof oil.

3. The electric actuated ball valve should be inspected regularly after installation. The main inspection items are as follows:

• (1) Wear condition of sealing surface.
• (2) Trapezoidal thread wear of stem and stem nut.
• (3) Whether the filler is out of date or not, and if it is damaged, it should be replaced in time.
• (4) After repair and assembly of electric valves, the sealing performance test should be carried out.

In the course of operation, all kinds of valve fittings of the electrically operated ball valve should be complete and intact. Bolts on flanges and brackets are indispensable. Threads should be intact and intact. No loosening is allowed. The fastening nuts on the handwheel should be tightened in time if loosening is found, so as not to wear the connection or lose the handwheel and nameplate. If the handwheel is lost, it can not be replaced by a live wrench. It should be matched in time. Packing gland should not be skewed or without pre-tightening clearance. For electric valves which are easily contaminated by rain, snow, dust and other dirt, the valve stem should be equipped with protective cover. The ruler on the electric ball valve should be complete, accurate and clear. Lead seals, caps and pneumatic accessories of electric valves should be in good condition. Thermal insulation jacket should be free from depression and crack. It is not allowed to knock, stand or support heavy objects on electric ball valves in operation, especially non-metallic electric ball valves and cast iron electric ball valves.

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What is a Ball Valve?

A ball valve is a shut off valve that controls the flow of a liquid or gas using a rotary ball having a bore. Ball valves are a type of quarter-turn valve along with plug valves and butterfly valves. They can be operated manually or by using an actuator.

How does a Ball Valve work?

The simplest operation of a ball valve is through the use of a wrench or a lever manually turned by an operator. Torque is applied to rotate the lever arm by 90° either clockwise or counterclockwise to open or close the valve. If the lever arm is parallel to the pipe, it indicates that the valve is open. If the lever arm is perpendicular to the pipe, it indicates that the valve is closed.

Parts of a Ball Valve

Ball

The ball is a sphere that has a hole in its center. The hole in its center is called the bore. The bore serves as the flow opening of the fluid when the cross-section of the fluid flow path and the bore is coplanar. Otherwise, the flow is throttled. A ball valve may have a solid ball or a hollow ball. A solid ball has a constant opening diameter throughout its structure, which helps the fluid to smoothly flow at a constant velocity. A hollow ball, on the other hand, has a hollow internal structure, and the space inside it allows more fluid to pass through the valve. However, the larger space creates turbulence and high velocities. A hollow ball is more lightweight and cheap compared to a solid ball.

Shaft

The shaft connects the ball to the control mechanism that rotates the ball. The shaft has seals such as O-rings and packing rings to seal the shaft and the bonnet to avoid leakage of the fluid. The shaft may be manually operated by a lever or a handwheel or operated by an electric, pneumatic, or hydraulic actuation.

Bonnet

The bonnet is an extension of the valve housing that contains and protects the shaft and its packing. It may be welded or bolted to the body. It is also made of hard metal and it covers the opening made from connecting the shaft to the external control mechanism.

Seat

The valve seats provide sealing between the ball and its body. The upstream seat is adjacent to the inlet side of the valve. The downstream seat is found on the opposite side of the upstream seat which is adjacent to the discharge side of the valve.

Causes of Ball Valve leaking at handle and internal

I. Causes of leaking ball valve

1. Causes of ball valve leaking internal during construction:

• Improper transportation and hoisting may cause overall damage to the ball valve, resulting in internal leakage of the valve;
• When leaving the factory, the ball valve was not dried and anti-corrosion treated after the completion of hydraulic pressure, resulting in corrosion of the sealing surface and internal leakage;
• The protection at the construction site is not in place, no blind plates are installed at both ends of the valve, rainwater, sand, and other impurities enter the valve seat, causing leakage;
• During installation, no lubricating grease was injected into the valve seat, causing impurities to enter the rear of the valve seat or internal leakage caused by burn during welding;
• If the ball valve is not installed in the fully open position, the ball will be damaged by the welding spatter. If the ball valve is not installed in the fully open position, the ball will be damaged by the welding spatter. When the ball with the welding spatter is opened and closed, the valve seat will be further damaged, resulting in internal leakage.
• The sealing surface is scratched by welding slag and other construction leftovers;
• If the ball valve stem drive sleeve or other accessories are misaligned with the assembly angle, the valve will leak.

2. Causes of ball valve leaking internal during operation:

• The most common reason is that the operation manager does not maintain the industrial ball valve in consideration of the relatively expensive maintenance cost, or the lack of scientific valve management and maintenance methods does not carry out preventive maintenance on the valve, resulting in equipment failure in advance;
• Internal leakage caused by improper operation or failure to maintainbyh maintenance procedures;
• During normal operation, the construction remains scratch the sealing surface, causing internal leakage;
• Improper pigging causes damage to sealing the surface and internal leakage;
• If the valve is not maintained or moved for a long time, the valve seat and ball will be locked, and the sealing damage will be caused when the valve is opened and closed to form internal leakage;
• If the valve switch is not in place, internal leakage will be caused. No matter whether the ball valve is opened or closed, the general inclination is 2 ° ~ 3 °, which may cause leakage;
• Many large caliber ball valves have stem stop blocks. If they are used for a long time, rust, dust, paint and other sundries will accumulate between the stem and stem stop blocks due to rust and other reasons, which will cause the valve unable to rotate in place and cause leakage. If the valve is buried, extending the stem will produce and drop more rust and impurities, which will prevent the ball from rotating in place. Cause valve leakage;
• The general actuator is also limited. If it is corroded for a long time, the grease will harden or the limit bolt will be loose, which will make the limit inaccurate and cause internal leakage;
• The valve position of the electric actuator is set forward, which is not closed in place, causing internal leakage;

Due to the lack of periodic maintenance, the sealing grease becomes dry and hard, and the dried sealing grease accumulates behind the elastic valve seat, hindering the movement of the valve seat, and resulting in seal failure.

II. Cause of ball valve leaking at handle

• First check the limit of the valve to see whether the internal leakage of the valve can be solved by adjusting the limit.
• Inject a certain amount of grease to see if it can stop the leakage. At this time, the injection speed must be slow. At the same time, observe the change of the pointer of the pressure gauge at the outlet of the grease gun to determine the internal leakage of the valve.
• If the leakage cannot be stopped, it may be caused by the hardness of the early injected sealing grease or the damage to the sealing surface. It is recommended to inject valve cleaning fluid at this time to clean the sealing surface and valve seat of the valve. Generally, it should be soaked for at least half an hour. If necessary, it can be soaked for several hours or even days, and the next treatment should be carried out after all solidified substances are dissolved. In this process, it is better to open and close the movable valve several times.
• Refill the lubricating grease, open and close the valve intermittently, discharge the impurities from the back cavity and seal the surface of the valve seat.
• Check in the fully closed position. If there is still leakage, inject the reinforced sealing grease, and open the valve chamber for venting at the same time, to generate a large pressure difference, which helps seal. In general, the internal leakage can be eliminated by injecting the reinforced sealing grease.

If there is still internal leakage, the valve shall be repaired or replaced.

How to fix a Leaking Ball Valve?

1. Shut off the fluid flow to the leaking valve.
2. Remove the handle from the stem.
3. Loosen and remove the packing nut.
4. Inspect the packing glad and internal components closely. Look for damage or signs of wear and tear. At this point, you must diagnose the valve and choose from the following solutions:
   • Re-lock the packing gland evenly.
   • Increase packing material.
   • Replace old packing materials with new ones.
   • Replace the valve entirely.

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Industrial Gate Valve Problems

Why do gate valves fail?

The most common causes of gate valve failure are wear and corrosion of the wedge and seat. The inner parts of a gate valve tend to wear over time. And corrosion can cause the wedge to stick in the open or closed position. When the handwheel is stressed, the stem leading from the handwheel to the wedge tends to break off, rendering the valve useless.

In addition, the stem packing and the bonnet gasket in the gate valve are wearing parts and need to be replaced within the period recommended by the manufacturer, which may also cause leakage if not replaced.

GATE VALVE REPAIR

Can I repair gate valves? 

Yes, Please refer to the following problems and solutions

1.Problem: Leakage between gate valve and valve connection

1-1.Corrective Action:

First, check whether the bolts connecting the valve to the gate valve are tight, if not, its seal ring and flange sealing groove surface often lead to leakage if they are not sufficiently connected. Check that the bolts and nuts are in order and tighten all bolts until the seal is pressed. Next, check the size and accuracy of the seal and flange sealing groove surface, if the seal contact surface is the wrong size or too rough, repair or renew it. Also check the contact surface of the seal ring and flange sealing groove for defects such as a little erosion, sand holes, sand holes or impurities, if so, weld, repair or clean accordingly.

2.Problem: Leakage from bonnet

This failure phenomenon often occurs in the packing seal leakage.

2-1.Corrective Action:

Firstly, check that the seal fits correctly and is compatible with the seal groove, if there is a problem, the seal should be replaced or the seal groove repaired. Secondly, check if the seal has burrs, breaks, and twists off, if so, the seal should be replaced. Then, check the surface of the seal groove for roughness or other defects and if there are defects, remove them or renew the damaged parts.

When the bonnet or bracket uses compression seal packing, the installation of the packing should be checked and if the packing is found to be installed backward, it should be removed and installed according to the correct method.

3.Problem: Leakage from valve body cavity

During the casting process, sometimes casting defects may appear in the valve body, such as grit holes and sand holes. They are difficult to detect during machining without the requirement for non-destructive testing, but once pressure is applied to the valve body, hidden casting defects are exposed.

3-1.Corrective Action:

If this is the case, it can be welded, repaired, or renewed as appropriate according to the standard.

4.Problem: Leakage from valve seat and valve wedge

4.1 Leakage occurs on the valve seat and the valve wedge, which is the most common phenomenon during the installation or maintenance of gate valves. There are generally two types: one is leakage on the sealing surface; the other is leakage at the sealing root.

4.1-1.Corrective Action: The first thing to check is the accuracy of the sealing contact surface of the valve seat and the valve wedge. The sealing surface needs to be ground, and if there is a rough surface, remove and regrind it. Next, check the sealing surface for defects such as pockmarks, indentations, grit holes, cracks, etc. If this is the case, the seat and wedge should be replaced. For valve seats with compression springs, check that the spring force of the pressure spring meets the requirements, if the spring force is low, the compression spring should be renewed. In addition, check that the T-shaped coupling between the valve wedge and the stem is not too loose and that there is no slope, if so, the wedge should be removed and adjusted to the optimum size.

4.2 When installing the valve, it is easy to drop in foreign objects such as welding checks, scrap iron, and impurities.

4.2-1.Corrective Action: Clean up the debris before installation. If you forget to clean or clean incompletely, the valve wedge will not reach the desired closing depth and cause leakage, in which case the valve body should be removed and cleaned.

The valve seat should be installed using a special tool. Check that the valve seat is installed correctly, if the threads are less deep than expected the seat will leak, in this case, the seat should be installed using a special tool.

How do you fix a gate valve that won’t open or close?

The first possibility is that the valve torque is too large and requires more force to close or open, replace the actuator with a larger size

The second possibility is that, when the valve is installed in the pipeline, there is a build-up of welding slag or debris at the bottom of the valve blocking the gate to close, and the debris needs to be cleared. The third possibility is that the gate and the valve seat have been damaged and need to be repaired and replaced in time.

Refer specifically to section 4.

How to replace a gate valve, Replace gate valve with ball valve

Close the shut-off valve in front so that the medium is in a static state, and discharge the medium in this section of the pipeline, if it is a flange-connected gate valve, you need to remove the bolt and nut of the connection, clean the sealing surface, replace the gasket and reconnect the new ball valve. If it is a threaded connection gate valve, just screw it down. In the case of SW or BW connections, cut down and weld the new ball valve in place.

Water Gate Valve Problems

My gate valve is stuck and open, what should I do

If your gate valve is open and you cannot close it, then the only option is to drain it. In some cases, plumbers can quickly replace valves, but this does not pose a risk. In most cases, when your gate valve has a problem, if your gate valve is open, it is best to drain the water.

The problem that the gate valve cannot be opened

If you have a gate valve that cannot be opened, it is usually due to a broken spindle. The reason for this usually rest is that when the valve is closed due to not dirty build, scale, or other, the plumber or master will tighten the thread causing the thread to break. If the valve cannot be easily closed, it is best to replace the gate valve while draining water, to further avoid gate valve problems and cause more costs.

How to replace the gate valve without losing hot water

The best way to replace the valve is to freeze the pipe first, and then replace the valve. The only other way is to close the gate valve and disconnect the bottom pipe. Once you leave the top nut of the supply pipe, you can switch the valve very quickly. This must be done by a skilled emergency plumber.

My gate valve can’t close properly, why?

The reason why the valve cannot be closed normally is that as the gate valve ages, you will find dirt or scale accumulation, causing the closing mechanism to fail to close normally. The best way to solve this problem is to either clean the valve thoroughly or replace the gate valve.

When replacing the gate valve, whether it must be emptied first

As explained in the previous paragraph, to replace any valve, you don’t always have to empty it, as long as you have the experience and tools to do so.

What causes the gate valve to rupture

The reason for the rupture of the gate valve is that the valve is fragile and the pressure is too high when the gate valve is closed. The spindle thread is not deep enough to enter the valve, so if the pressure is too great, there is not much room to stop any resistance. It’s a bit like breaking a twig instead of breaking a stick.

ZECO Valve is a Gate Valve manufacturer. If you are interested in our products, please contact us. Email: commercial@zecovlave.com

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