Analysis of common failures of boiler safety valve (a)

1, Introduction



Is a very important safety valve to protect the valves, widely used in a variety of pressure vessels and piping system, when the system pressure exceeds the set pressure value, it will automatically open, the excess emissions into the atmosphere of the medium and to pressure vessels to ensure the safe operation of pipeline systems and to prevent accidents, and when the system pressure back down to work pressure or slightly below the pressure of work and can automatically shut down. Safety work is directly related to the reliability of equipment and personal safety, it is necessary to pay attention.



2, safety analysis of common causes and solutions



2.1, valve leakage



In the normal operating pressure equipment, valves and valve seat sealing surface took place more than allowed levels of leakage, valve leakage will not only cause loss of media. In addition, the media will continue to leak so hard sealing material destruction, but common safety valve sealing surface of metal materials are metallic materials, although the formation make it bright and clean, but in the medium under pressure to do that do not leak very difficult. Therefore, the working medium is steam safety valve, set pressure value, if the naked eye can not see the export side, but also to listen to no leakage on the sealing performance that is qualified. Generally caused by valve leakage is due mainly to the following three conditions:



A situation is that the dirt fell on sealed surface impurities will stay sealed mat surface, resulting in valve core and the gap between the valve seat, which valve leakage. Eliminate this failure is clear that the sealing surface of falling dirt and impurities, the general shutdown in preparation for the size of the boiler repair, the first security door so steelyard weight test run, if the leakage was found after shutdown for the disintegration of maintenance, if it is point furnace steelyard weight test run after the security gate leakage was found, it is estimated that this situation is caused by the stone roller in the running after 20 minutes cooling time before running the rudder on the sealing surface to erosion.



Another situation is the sealing surface damage. Sealing surface damage caused by the following main reasons: First, material adverse sealing surface. For example, in the furnace 3 to 9, the main security gate as a result of many years of maintenance, the main security gate valve core and valve seat sealing surface have been developed generally very low, so that the hardness of the sealing surface is also greatly reduced, resulting in sealing performance, the elimination of such is the best way is to continue turning the original sealing surface, and then asked to re-surfacing by drawing processing, improve the surface hardness of the sealing surface. Attention to a certain process to ensure the quality of processing, such as the sealing surface cracks, defects such as trachoma must go on after the turning process. New processing spool valve seat must be in line with requirements of drawings. General YST103 currently used for processing steel welding rod spool sealing surface on the relatively good results. Second, repair of poor quality, the spool valve seat grinding quality standards can not eliminate this failure is based on the degree of injury after turning the use of abrasive or abrasive methods to repair sealing surface.



Another safety valve leakage caused due to improper assembly or improper parts size. Spool in the valve seat assembly process is not fully to have a light or a combination of surface phenomena, or spool valve seat sealing surface is not conducive to sealing too. The elimination method is to check with the space around the spool size and uniformity to ensure the valve core hole with the top sealing surface异正degrees, inspection departments do not allow lift spool space; in accordance with the drawings called for a suitable sealing surface to reduce the width to achieve effective sealing .



2.2, combined with body surface leakage



Means the combination of upper and lower body surface between the leakage phenomenon, caused by leakage of the main reasons that the following aspects: First, combined with the bolt face tight or tight enough partial force, resulting in a bad combination of surface sealing.

 

ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
We can offer more Knife Gate Valve Information.If you need us according your spcification to produce the Knife Gate Valve .
Need, please e-mail to valve401@gmail.com a