Views: 219 Author: Site Editor Publish Time: 2021-10-18 Origin: Site
Gate valve refers to the valve that the ram can move along the vertical direction of the channel axis, which is mainly used to cut off the medium in the pipeline.
Advantages:
l The fluid resistance is small;
l The torque required for opening and closing is small;
l It can be used in the loop network pipeline with medium flowing in two directions;
l When the valve is fully open, the erosion of the sealing surface by the working medium is smaller than that of the stop valve;
l The structure is simple and the manufacturing process is good;
l The length of the structure is short.
Disadvantages:
l Large installation space is required;
l Generally, gate valves have two sealing surfaces, which add some difficulties to machining, grinding, and maintenance;
l The opening and closing time is long.
Butterfly valve is a kind of valve which uses disc opening-closing parts to open, close, and regulate the fluid channel.
Advantage:
l The utility model has the advantages of simple structure, small volume, light weight, and less consumables;
l Quick opening and closing with small flow resistance;
l According to the strength of sealing surface, double flanged butterfly valve can be used for powdery and granular media.
Disadvantages:
l The range of flow regulation is small;
l Due to the limitation of structure and sealing material, double offset butterfly valve is not suitable for high temperature and high-pressure pipeline system;
l The sealing performance is worse than that of metal seated ball valve and globe valve.
The opening and closing part of the stainless-steel ball valve is a ball, which uses the ball to rotate 90 ° around the axis of the stem to achieve the purpose of opening and closing.
Advantage:
l It has the lowest flow resistance (0 actually);
l It can be reliably used in corrosive medium and low boiling point liquid;
l In a large range of pressure and temperature, it can achieve complete sealing;
l The top entry ball valve can realize fast opening and closing without impact;
l The spherical closing part can be positioned on the boundary automatically;
l The working medium is sealed reliably on both sides;
l When the segmented ball valve is fully opened or closed, the sealing surfaces of the ball and valve seat are isolated from the medium, so the medium passing through the valve at high speed will not cause the erosion of the sealing surface;
l Ball valve is the most reasonable valve structure for low temperature medium system;
l The valve body of the full port ball valve is symmetrical, especially the welded valve body structure, which can well withstand the stress from the pipeline;
l The closing part can withstand the high-pressure difference.
l The actuated ball valve with all welded valve body can be directly buried underground and its maximum service life can reach 30 years, so the high-pressure ball valve with all welded valve body is the most ideal valve for oil and gas pipelines.
Disadvantages:
l The main sealing ring material of trunnion mounted ball valve is polytetrafluoroethylene, so it is inert to almost all chemical substances, which has the comprehensive characteristics of small friction coefficient, stable performance, not easy to aging, wide range of temperature application, and excellent sealing performance. The physical characteristics of PTFE include high expansion coefficient, poor sensitivity to cold flow, and poor thermal conductivity, so the sealing design of valve seat must focus on these characteristics.
l Its regulating performance is worse than that of stop valve, especially pneumatic valve or electric valve.
