Stainless Steel Floor Drain,Toilet Floor Drain Super Durable,Shower Floor Drain For Bathroom,Kitchen Floor Conceals Floor Drain Heshan Zhongxin Sanitary Ware Ind., Co., Ltd , https://www.baolongfaucets.com
2. Problem Analysis The leakage of stainless steel bellows globe valve is generally divided into two kinds: inner leakage and outer leakage. There are many causes of leakage. Endocrine is generally a factor in the failure of a liquid medium containing solid impurities to destroy the sealing surface. Combined with the analysis of field use, the main reason for stem leakage is related to the valve structure, working environment, and operating methods.
2.1 Structure The valve stem adopts double seal structure of corrugated pipe and packing. The corrugated pipe is welded into the bellows assembly with the inner lining ring and the outer lining ring, and then welded with the valve stem and the guide body to block the leakage of medium through the valve stem. The stem moves up and down from the flat key I until the upper end of the flat key I comes into contact with the lower end of the underfill. Because the underfill is made of PTFE material, the material, if the valve is opened excessively, it will cause the flat key I to be embedded in the packing, the valve cannot be opened and closed, and the bellows assembly is struck, causing leakage of the medium along the valve stem. The tensile length and the compression amount of the bellows are determined according to the stroke of the valve. If the tensile or compression exceeds the limit, the bellows may be damaged, causing the small braided pipe to rupture and the seal to fail. Therefore, it is necessary to increase the limit devices for opening and closing the valve, so that during the opening and closing of the valve, the bellows always expands and contracts within the design range. 2.2 Working Environment The harsh working environment of the bellows globe valve is also a cause of its failure.
As the bellows shut-off valve installed in the hull is working in the salt fog environment for a long time, and the upper part often has condensate dripping, causing the upper thrust ball bearing to erode. In severe cases, it will cause contact corrosion with the valve stem. 2.3 Operation in use If excessive Opening or closing the bellows shutoff valve may cause the valve not to meet the relevant performance requirements. When the valve is over-closed, it is possible to crush the sealing surface and cause the seal to fail when the valve is used again. When the valve is opened excessively, the bellows assembly may be operated, causing the valve to leak.
3. Improve the problems existing in the analysis of valves and improve their structure, operation and environment. The first is to increase the limit welfare fee for the flat key I. Ask the bottom filler of the PTFE material to add a thick 3 stainless steel pad to prevent the filler from getting dirty and limiting the stem.
When the valve is closed, if the valve fails to shut off, it should not be forced to close. Instead, open the valve, flush it again with fluid for a period of time, and then close it again. If it still cannot be closed, check the grinding sealing surface. When the valve is opened, when the valve is opened to a certain height and the valve stem encounters a small resistance, try not to continue the forced opening to extend the life of the valve stem and its sealing assembly. The stop valve with the thrust ball bearing on the upper part of the valve stem should avoid the direct dripping of condensation water at the position of the valve door leading to corrosion of the valve stem during installation.
4. Conclusion After the bellows shut-off valve was improved, there was no recurrence of failures such as bellows cracking, stem rusting, and external leakage.
1. The use of stainless steel bellows shut-off valve installed in the pipeline of the ship's power plant, in the course of the valve valve stem leakage and valve stem rust and other issues, although repaired. But the problem recurred. After analyzing the cause of the failure, a suitable solution was adopted to eliminate the failure and ensure the performance of the valve.