Steam valve leakage is a common phenomenon in factories. Steam leakage causes increased energy consumption and fuel costs, and also easily leads to safety problems in the production process. Steam leakage also means environmental and emission problems and other impacts.
In daily work, our steam engineers find that the initial leakage of the steam valve is often small and difficult to detect. In particular, the steam valve leakage, only a long time of observation and testing can be found.
When the amount of steam leakage is large, maintenance engineers or steam engineers found that the cost and necessity of maintenance is often increased a lot, the planned management of the factory valve is the primary solution to eliminate valve leakage.
Steam valve leakage is common stem stuffing box leakage, which is the main performance of running, risk, leakage, often seen in the construction site, factory. The reasons for the leakage of the stuffing box include the corrosion, temperature and pressure incompatibility of the packing and the working medium; The filling method is wrong, especially the whole filler is put into the spare screw, which is the most easy to produce leakage; Valve stem processing accuracy or surface finish is not enough, or oval, or notched; The stem has been pitting or rusting due to lack of protection in the open air; Stem bending; The filler has aged after too long use. Operation is too hard. DBF200 bellows sealed globe valve is the solution to eliminate leakage at the stem completely. Use bellows instead of stuffing boxes to ensure no valve leaks in any condition.
Steam valve leakage internal leakage is an important source of leakage, internal leakage is mainly manifested as the closure of the leakage, we will stuffing box leakage is called external leakage, the closure of the leakage is called internal leakage.
Closing parts leak, inside the valve, not easy to detect. Closing parts leakage can be divided into two categories: one is sealing surface leakage; The other is leakage at the root of the seal. Causes of leakage include poor grinding of sealing surface; The sealing ring is not tightly matched with the valve seat and valve disc; Disc and stem connection is not reliable; Stem bending and twisting, so that the upper and lower closing parts are not in the center; Close too fast, sealing surface contact is not good or already damaged; Material selection is inappropriate, can not withstand the corrosion of the medium; When the globe valve and gate valve are used for adjustment, the sealing surface cannot withstand the impact of the high-speed flow medium, especially the hardness and abrasion resistance of the sealing surface caused by incorrect heat treatment; Some media, gradually cooling after the valve is closed, so that the sealing surface appears thin cracks, will also produce erosion phenomenon; , some sealing ring and seat, the use of thread connection between the valve disc, easy to produce oxygen concentration battery, corrosion release; Due to welding slag, rust, dust and other impurities embedded, or mechanical parts fall off in the production system to block the spool, so that the valve can not be closed tightly.
The internal leakage of the steam valve leakage sometimes comes from the failure of the stem lifting mechanism, the stem lifting failure, the operation is too fierce to make the thread damage; Lack of lubricant or lubricant failure; Stem bending and twisting; Insufficient surface finish; With the tolerance is not allowed, bite too tight; Improper material selection; For example, stem and stem nut for the same material, easy to bite; The thread is corroded by the medium (refers to the hidden stem valve or the valve stem in the lower part); Open-air valves lack protection, stem threads sticky sand, or by rain, frost and snow rust.
Other steam valve leaks we have found include cracking of the valve body: usually caused by freezing. When the weather is cold, the valve should have heat preservation and tracking measures, otherwise after production should be condensed water in the valve and the connecting pipeline drain. The leakage of the steam safety valve is mainly the damage of the sealing surface. The steam leakage caused by the frequent take-off of the steam safety valve is often the problem of pressure setting and the pressure difference of the safety valve back seat.