Different from the problems existing in the traditional processing technology of stem, now the stem in the valve parts has obviously advantage : new valve rod thread with homemade extrusion, threaded with high intensity, precision is more accurate;The thread part is consistent with the light pole position, and overcome the problems that are prone to distortion in the process of thread rolling.
Now in the production of the stem in the valve parts, the precision of the rod part can achieve the mirror effect. The opening and closing are easy and the sealing performance is better.The inverted part adopts the numerical control technology to take shape at one time, with high precision and better sealing performance.The t-groove of the end part adopts forging process, which is high in efficiency and low in cost.The whole stem production process can reach the international advanced level.
On the valve parts in strong corrosion or volatile and harmful under process conditions, once the stem seal is broken, strong corrosion, volatile and harmful medium leakage from the stem, serious consequences for the surrounding environment and personal safety.At this time, using bellows stem seal can effectively solve the above problems
The stem bellows in valve parts are generally made of stainless steel.Such special protection control valve bonnet structure of packing box to avoid and fluid contacts, once the bellows fracture, in above the bellows stuffing box can prevent the bellows rupture structural failure time have serious consequences.In engineering practice, the choice of the form of bellows seal should be fully aware of the bellows sealed pressure rating will appear with the increasing of temperature and reduced, fluid solid particles can't exist and bellows material the longest cycle action life, etc.
While the stem in valve parts stays in corrosion resistance that stainless steel is able to endure, strong corrosion medium is wet chlorine, wet chlorine contained traces of hydrochloric acid can be made of stainless steel bellows corrosion was quickly.Therefore, the stem in valve parts should avoid the use of corrosion in the above places, or to select anti-corrosion materials for processing this part.