Affect the safe operation of the factors regulating valve and Countermeasures (Part One)

1, Introduction



In the higher degree of automation of chemical control system, regulating valve as the implementation of automatic adjustment system, the terminal device to receive control signals to achieve the regulation of chemical processes. It is directly related to the sensitivity of the action-conditioning systems quality. According to the site of about 70% of the actual statistics of the failures come from regulating valve. Therefore, routine maintenance review and analyze the impact the safe operation of the factors regulating valve and Countermeasures



2, card blocking



Valve recurring problem is that card blocked, often appear in the new transport system and the overhaul of investment put into operation in the initial stage, due to pipe welding slag, rust, etc. at the cutting mouth, oriented so that part of blockage caused by poor circulation media, or regulating valve repair in the tight packing, resulting in increased friction, leading to large-signal small-signal non-action motion overshoot phenomenon. |

Troubleshooting: You can quickly open, off-line or adjust the valve, vice, so that dirt from the Vice-line or adjust the valve was washed medium run. Another way to stem tube clamp tight, plus the signal pressure in the case, the positive and negative force rotating stem, so that spool flash card office. If it is not an increase of gas pressure to increase the drive power source has repeatedly moved up and down several times, you can solve the problem. Should the motion not, it would take the disintegration of treatment.



3, leakage



3.1 valve leakage, valve stem length of the discomfort. Air to open valve, stem long stem up (or down) the distance is not enough, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage. Similarly, gas off valve stem is too short, resulting in gaps between the valve core and valve seat can not be full access, leading to lax customs and internal leakage.



Solution: should be shortened (or extended) regulating valve stem so that the length of the right valve so that it no longer internal leakage.



3.2 Packing leak



Packing into stuffing after the axial pressure imposed by the gland. Because the plastic filler to produce a radial force, and close contact with the valve stem, but this contact is not very uniform. Some parts of the loose contact with some parts of the tight contact with, or even no contact at some parts. Regulating valve in the use process, the stem with the filling between the relative movement, this movement is called axial movement. The use of the process, with the high-temperature, high pressure and permeability of fluid medium strong, regulating valve packing leak letter is part of larger phenomena. Is mainly due to leakage caused by filler interface leakage, will appear for the textile and packing leakage (pressure medium along the filler-gap between the small outward leak). The interface between the stem and the packing leakage is due to the gradual attenuation of the contact pressure filler, filler causes such as their own aging, when the pressure medium will be along the contact between the filler and the valve stem outward leakage gap.



Countermeasures: In order to facilitate the filler loading, in the stuffing to the top chamfer, in the stuffing box placed at the bottom of the smaller gap erosion-resistant metal protection ring (with the contact surface can not fill slope) in order to prevent the fill material was medium pressure introduced. Stuffing box packing contact with the ministries and part of the metal surface to be finished, in order to improve the surface finish and reduce packing wear and tear. Flexible graphite packing selected because of their good gas tightness, the friction is small, changes after long-term use of small, wear the burning of a small, maintenance easy, gland bolts re-tightened after the friction does not change, pressure and resistance heat well, is not within the medium erosion, with the stem and the stuffing does not occur within the contact with the metal pitting or corrosion. In this way, the effective protection of the valve stem seal stuffing to ensure the reliability of sealing packing and long-term. 

 

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