Siristar News

Valve in the process of using it will also have many small problems, we do not pay attention to a little will cause failure, then the following are often encountered problem-solving methods for your reference.

First, the methods to prevent packing leakage:

1. Regular maintenance: valves should be cleaned and maintained regularly. The sealing surface of the packing should be cleaned and degreased before installing new packing. The packing should be installed in accordance with the manufacturer’s instructions, and after installation, it is necessary to tighten the stem nut evenly.
2. Packing material selection: according to different working conditions and service requirements, select suitable material for sealing packing according to the actual situation, such as hard-wearing materials (such as hard rubber) for steam valves; soft rubber is suitable for water valves, and Teflon (PTFE) is suitable for low pressure and low-temperature mediums.
3. Packing joint design: in order to avoid leakage caused by improper jointing, we must pay attention to packing joints during the design phase so that they can be installed easily without any damage or distortion after being installed.
4. Packing pressure adjustment: when installing the valve packing, it must be ensured that there is a certain gap between the valve casing and the sealing surface of the valve body when it is closed completely so that there won’t be any leakage caused by excessive pressure from both sides during normal operation because this may cause damage.
5. Timely replacement: filler after a certain period of time, to be replaced; take protective measures to prevent rust and corrosion, has been rusted to be replaced, the stem bending to straighten or update; stem processing is not qualified, to repair or replace, the minimum surface finish should reach 5, the more important, to reach more than 8, and no other defects.
6. The operation should pay attention to the smooth, slow opening and closing, to prevent drastic changes in temperature or media impact.

Second, the closing piece leakage prevention methods:

1. must be carefully tested for pressure and leakage before use, found sealing surface leakage or sealing ring root leakage, to be dealt with before use.
2. to check in advance whether the valve parts are intact, can not use the valve stem bending or valve flap and stem connection is not reliable.
3. valve shut tight to make a steady force, do not make a fierce force, such as found between the sealing surface contact is not good or blocked, should immediately open a little, so that debris out, and then carefully shut tight.
4. the selection of valves, not only considers the corrosion resistance of the valve body but also considers the corrosion resistance of the closing parts.
5. to follow the structural characteristics of the valve, the correct use, and the need to regulate the flow of parts should be used to regulate the valve.
6. for the media cooling after closing the valve and the temperature difference, close the valve a little after cooling.
7. when the valve seat, valve flap, and seal are connected by thread, PTFE tape can be used as packing between the threads so that there is no gap.
8. valves with the possibility of falling into impurities should be added to the valve before the filter.

Third, the prevention of valve stem lift failure:

1. carefully operation, do not make a violent effort to close, do not open to the upper dead point, and open enough to turn the handwheel upside down one or two turns so that the upper side of the threads closes so that the medium to push the stem upward impact.
2. frequently check the lubrication, to maintain a normal lubrication state.
3. do not use a long lever to open and close the valve, and workers who are used to using a short lever should strictly control the force in proportion to prevent twisting the stem (referring to the valve directly connected to the handwheel and stem).
4. improve the quality of processing or repair to meet the specification requirements.
5. materials to be corrosion resistant and adaptable to operating temperatures and other working conditions.
6. the stem nut should not be made of the same material as the stem.
7. the use of plastic for the stem nut, to check the strength, not only consider good corrosion resistance and a small coefficient of friction but also must consider the strength of the problem, if the strength is not enough do not use it.
8. open-air valves to add stem protection sleeve.
9. Always open the valve, to regularly turn the handwheel, so as not to rust the stem.