The valve cavity of the ball valve is working at high pressure for a long time due to the requirements of production for ball valves in operation. When the grease injection hole leaks, emergency treatment can usually only be carried out under pressure.
Repair under pressure
Given the leakage of the grease injection hole caused by the dirt in the grease injection channel causing a jamming of the spring and jamming between the steel ball body and the sealing surface, you can inject cleaning fluid or oil into the grease injection mechanism of the ball valve, and soak it for some time in the grease injection channel. The jammed dirt will quickly disintegrate or soften after the immersion of the cleaning solution, so that the steel ball and spring return to their original positions, which can effectively repair the leakage of the grease injection hole. However, when the amount of leakage from the grease injection hole is great, it will be difficult to inject the cleaning solution. After the cleaning solution is injected, if there is no leakage in the grease injection hole, professional tools (as shown in Figure 4) can be used to push the check valve of the grease injection nozzle by forward and reverse rotation of the top T shape to make the top rod moves up and down. If the check valve on the valve body has failed, the high-pressure medium in the valve cavity of the ball valve will be discharged through the release channel of the special tool. During the test, if the discharge volume of the medium of the venting channel is large, it can be seen that the check valve has seriously failed, and the check valve cannot be disassembled, replaced, and repaired; if the discharge volume of the venting channel is small or zero, it is proved that the check valve is working. The check valve of the grease injection nozzle can be disassembled, replaced and repaired.
Emergency treatment under pressure
In view of the failure of the check valve, the damage to the ball body, sealing surface of the check valve of the grease injection nozzle and the riveting edge, the failure of the spring and other conditions that cannot be repaired under normal pressure, only emergency locking joints or grease injection nozzles adapters can be prepared in advance, as shown in Figure 1.
The sealing is formed between the front joint surface and the grease injection nozzle, and the rear end is controlled by providing a ball valve or a grease injection nozzle to ensure emergency plugging and the operation of the ball valve. When there is no pressure, repair the ball valve.
Figure 1 Emergency locking adapters for grease nozzles
Replacing grease nozzles under pressure
Given the situation that the grease injection nozzle in operation must be replaced in time to deal with the leakage of the grease injection hole, the failed grease injection nozzle can be disassembled and replaced under pressure online by using the T101b hole drilling machines with pressure and its accessories from TDW Company. The hole drilling machine with pressure is fixed on the ball valve and the customized sealing cover at the bottom is used for sealing. The sleeve is used to clamp the grease injection nozzle instead of the hole drilling machine. Use the forward and reverse rotation of the upper and lower cavities of the T101b hole drilling machine with pressure and the rocking handle to realize the assembling of the grease injection nozzle, thereby eliminating the leakage of the grease injection hole (as shown in Figure 2). However, the customized cover plate has poor adaptability and the sealing is very difficult due to the inconsistent working parameters such as specifications and installation positions of ball valves. In addition, the installation process of the grease injection nozzle is based on experience. Once the position is misaligned, the replacement of the grease nozzle under pressure will not be possible.
Figure 2 T101b hole drilling machines with pressure installing and removing grease nozzles
Conclusions
The leakage of the one-way valve is a normal condition in actual work, and it is also an important cause of the jamming of grease injection. Therefore, it is necessary to modify its structure to improve the working stability.
Replacing the grease injection nozzle under pressure has high requirements. Improper treatment can easily lead to new situations and may cause safety accidents. Therefore, try not to use it as much as possible.
Grease the ball valve with lubricating grease and sealing grease. After meeting the working requirements of the ball valve, the grease filling channel of the ball valve should be filled with cleaning fluid or oil to avoid the leakage of the grease injection hole caused by the hardening of the grease and sealing grease.
Improve the structure of the existing ordinary grease injection nozzles, and carry out relevant test verifications, especially the design and research of special tools with emergency response functions after the sealing failure of the grease injection nozzles.
