Combined with the analysis of the on-site use situation, the reason for the leakage of the valve stem is mainly related to the valve structure, working environment and operation mode.
The valve stem adopts a double sealing structure of bellows and packing. The bellows is welded with the inner lining ring and the outer lining ring to form a bellows assembly, and then welded with the valve stem and guide body to block the leakage of the medium through the valve stem . The up and down movement of the valve stem moves upwards from the flat key until the upper end surface of the flat key contacts the lower end surface of the lower packing. Since the lower packing is made of PTFE material, if the valve is opened excessively, the flat key will be embedded in the packing, the valve can no longer be opened and closed, and the bellows assembly will be knocked to get stuck, causing the medium to leak along the valve stem. The stretching length and compression of the bellows are determined according to the stroke of the valve. If the limit is stretched or compressed, the bellows may be damaged, causing the small pipe to rupture and seal failure.
