How to Properly Store and Maintain Backup Gate Valves: Expert Tips for Backflow Prevention

Backup gate valves, backflow valves, and backflow preventer valves are critical components in plumbing, irrigation, and industrial systems. They protect against contamination by preventing reverse water flow and ensuring system integrity. However, improper storage and maintenance can compromise their functionality, leading to costly repairs or replacements. In this guide, we’ll explore actionable steps to store and maintain these valves effectively.

Valve Maintenance and Maintenance procedures

Appearance cleaning

Wipe the outside of the valve with a clean rag regularly every month to remove dust, oil and debris.
For dirt that is difficult to remove, use a mild detergent, but avoid using highly corrosive chemicals.

Lubrication operation

Apply an appropriate amount of lubricant to the threads, shafts and other moving parts of the valve every quarter.
Before applying, remove the old lubricant and impurities on the surface of the parts to ensure the lubrication effect.

Seal inspection

Check the sealing performance of the valve once a month to observe whether there is leakage in the closed state.
You can judge whether the sealing performance is good by applying pressure and using leak detection agents or observing bubbles.

Maintenance operating procedures

Operation flexibility inspection

Perform manual operation once every six months to test the flexibility and resistance of the valve in the fully open and fully closed states.
If you find that the operation is stuck or abnormal resistance, you need to find out the cause and deal with it in time.
Parts inspection

Perform a comprehensive disassembly inspection of the valve every year, focusing on the wear and damage of the valve stem, valve core and valve seat.
Ensure that there are no scratches and rust on the valve stem surface. Minor wear can be polished; if the valve core and valve seat are severely worn, corroded or deformed, they should be replaced in time.
Anti-corrosion treatment

For valves exposed to humid or corrosive environments, the anti-corrosion coating needs to be checked and repaired regularly.
Hot-dip galvanizing, painting and other methods can be used for protection to ensure that the valve can maintain good performance in harsh environments.
Pressure test

Newly installed or repaired valves must be pressure tested before being put into use to ensure their safety performance.
For valves that are operating normally, it is recommended to perform a pressure test every 1-2 years to verify whether their performance is stable and reliable.
Recording and archiving

Make detailed records of each maintenance and maintenance operation, including operation time, personnel, content, problems found and treatment results.
Properly save relevant records to facilitate future analysis and improvement of valve use and maintenance work.

When performing valve maintenance and maintenance tasks, all safety regulations must be strictly observed. Before operation, it should be confirmed that the system has completely stopped running and the pressure has been relieved. At the same time, the operator is required to have the corresponding professional skills and rich experience to ensure the safety and effectiveness of maintenance work.

Maintenance and repair points of common valve types

Gate valve:

During maintenance, the gate valve should be stored in a dry and ventilated room, and both ends of the passage should be blocked. Regularly check the wear of the sealing surface and trapezoidal thread, remove dirt in time and apply anti-rust oil. After installation, be sure to perform a sealing performance test.

During maintenance, if the sealing surface is worn, the cause must be found out and corresponding treatment or replacement of parts must be carried out. At the same time, ensure that the gate is in a fully open or fully closed state, avoid using it to adjust the flow, so as to prevent erosion and accelerated wear of the sealing surface. The handwheel should be used for switch operation, and the principle of clockwise rotation for closing and counterclockwise rotation for opening should be followed.

Globe valve:

The maintenance method is similar to that of the gate valve, but attention should be paid to the flow direction of the liquid during installation to ensure that the liquid flows through the valve from bottom to top. Keep it clean during use and add lubricant to the transmission thread regularly.

During maintenance, the globe valve has a reliable shut-off function because the valve stem of the globe valve has a short opening or closing stroke. The valve seat and valve disc are usually easy to repair or replace without removing the entire valve from the pipeline. At the same time, pay attention to avoid overpressure operation to reduce mechanical wear on the sealing surface.

Butterfly valve:

Keep clean during maintenance and regularly add lubricating grease to the transmission parts. Some butterfly valves are filled with molybdenum disulfide lubricating paste, which needs to be added regularly to ensure sealing performance.

During maintenance, common butterfly valves are two types: wafer type and flange type. In the fully open state, the thickness of the butterfly plate is the only resistance for the medium to flow through the valve body, so the pressure drop generated by the valve is small, and it has good flow control characteristics. If a fault is found, stop using it immediately and find out the cause.

Ball valve:

When stored for a long time, make sure that both ends are blocked and in the open state. Keep clean during use and add lubricant to the transmission threads regularly. At the same time, avoid using it in a slightly open state to prevent the impact of the fluid on the valve.

During maintenance, the ball valve can only be fully opened or fully closed. It is not allowed to be used to adjust the flow to prevent erosion and accelerated wear of the sealing surface.
In addition, there are some suggestions for the maintenance and repair of check valves:

The check valve should be stored in a dry and ventilated room to prevent debris from entering its internal structure and causing damage; the channel openings at both ends should be sealed with a head to maintain its good sealing performance.

Check valves that have been stored for a long time need to be inspected regularly, the dirt in their inner cavity should be removed, and butter should be evenly applied to the processed surface for protection.

The operating status of the check valve in operation should also be checked regularly to detect and eliminate minor faults in time. If a major fault occurs, it should be removed for maintenance. After the inspection and maintenance is completed, the sealing test must be carried out again, and the fault situation and the inspection and maintenance process must be recorded in detail.

For the muffler check valve, during storage and transportation, the opening and closing parts should be ensured to be in the closed state, and the following measures should be taken for protection:

The valve disc should be fixed in the open position.

Use foam boards to block the inner openings at both ends of the diameter and plug them tightly with blind covers to prevent dust and rust, while keeping the channel clean and the end surface flat.

Properly pack and protect the cylinder part to ensure that it has shock and collision protection functions.

When placed, it should be kept stable, ensure that the pneumatic drive device is facing upward, and avoid mutual squeezing.

When placed for a long time, the dirt and rust on the two channels and the sealing surface and the protection of the welding port should be checked every three months. After removing the dirt and rust, anti-rust oil should be reapplied for protection.

The main function of the check valve is to prevent the backflow of the medium, so it should be widely installed on equipment, devices and pipelines. Silencer check valves are usually suitable for clean media and should not be used for media containing solid particles and high viscosity. On horizontal pipelines with a nominal diameter of 50mm, it is recommended to use vertical silencing check valves.

To prevent the valve from rusting, measures should be taken such as regularly applying anti-rust oil or grease on the surface of the valve body, especially in a humid environment. At the same time, regularly check whether the fasteners of the valve are loose and tighten them in time. Seals are key components to ensure the sealing performance of valves and need to be replaced regularly. It is generally recommended to replace them every 1-2 years, and seals that match the valve model should be selected when replacing.

Maintenance:

Common faults and solutions are as follows:

Valve disc is broken: This is usually caused by the medium pressure before and after the check valve being close to balance and “seesawing” each other, resulting in frequent slapping of the valve disc and the valve seat. To prevent this fault, it is recommended to use a check valve with a valve disc made of tough material.
Backflow of media: This may be caused by damage to the sealing surface or impurities being caught. The corresponding solution is to repair the sealing surface and clean the impurities.
When performing maintenance and repair of the check valve, the first step is to close the valve and cut off the power supply to ensure safe operation. At the same time, corresponding maintenance strategies should be formulated for different types of valves and use environments. If you encounter complex faults or difficult problems, it is recommended to seek support from professional technicians or contact the manufacturer for further guidance.

During maintenance and repair, pay attention to the following common problems:

Transmission part maintenance: Regularly check the transmission parts and add lubricating grease in time to prevent wear or jamming due to insufficient lubrication.

Precautions for grease injection: Control the amount of grease injection, accurately calculate the sealing capacity according to the valve size and type, and inject an appropriate amount of grease. At the same time, pay attention to the grease injection pressure, avoid it being too high or too low, and adjust it according to the actual situation, such as replacing the grease hole or using cleaning fluid to soften and harden the sealing grease and inject new grease.

Packing maintenance: Packing is a key component to ensure the sealing of the valve. To prevent leakage, it can be achieved by properly tightening the nuts on both sides of the packing gland, but be careful to avoid over-tightening at one time to prevent the packing from losing its elasticity.

Daily inspection: Check whether all parts of the valve are intact and complete, and whether the flange and bracket bolts are tightened and intact. At the same time, pay attention to whether the valve’s scale, lead seal, cap and pneumatic accessories are intact.

Avoid improper operation: It is strictly forbidden to hit the valve or use it as a cushion to knock other objects, and avoid standing on the valve or supporting heavy objects. The valve in operation should be avoided from knocking. When purging the process pipeline, it is necessary to pay attention to whether the process parameters borne by the valve are within the allowable range to prevent damage to the valve packing and body.

Special situation handling: When using a steam valve, you need to open it slightly to discharge condensed water, then gradually open it and reverse the handwheel a little to ensure tightness. In a low temperature environment, it is necessary to remove condensed water and accumulated water from the steam and water valves to prevent freezing and cracking. When the temperature of the high-temperature valve rises to above 200°C, the bolts need to be “hot-tightened” to maintain the sealing, but this operation should not be performed when the valve is fully closed.

The maintenance and repair of the valve are crucial to its stable operation, life extension and leakage prevention. If you are not familiar with the structure or operation of the valve, it is recommended to seek the assistance of professional technicians. In addition, it is necessary to perform standardized operation and maintenance in accordance with the valve manual and relevant standards.

Commonly used valve types and their characteristics in sewage treatment tanks

In the field of sewage treatment, valves are key equipment, and their selection and maintenance directly affect the stability and efficiency of the entire system. This article will introduce several commonly used valve types in sewage treatment tanks, including their structural characteristics, working principles and applicable scenarios, to help you better understand and apply these valves.