Electrochemistry corrodes metals in different forms. It does not only function between two kinds of metals, but also can cause potential difference due to differential solubility of solution, differential solubility of oxygen and the tiny difference in internals of metals, enhancing corrosion. Some metals have poor resistance. However, they can form sensational protective film – passive film after being corroded, preventing be corroded by media further. So, to realize the corrosion resistance...

For rising stem wedge gate valve, connection between stem and core loses efficacy which caused by corrosion, abrasion or improper operation during valve on-off, then, the core falls off. If the valve cannot be opened after being closed, the valve only can be cut out from the system and replaced. If the valve cannot be cut out from the system, it should be connected with other fluid system or stopped. 1. Repairing When the core falls off while cannot be cut out, change the assemble method...

Corrosion on valve body is considered that the metal materials are destructed under the environment of chemical or electrochemical environment. The corrosion is caused by spontaneous interaction between metal and surroundings. So, isolating metal from surroundings or using more nonmetal synthetic materials is the key of corrosion protection. Valve body including bonnet account the most of weight of valve and usually contact with medium. Therefore, choosing valve starts from the materials...

Intelligent pneumatic ball valve is driven by pneumatic actuator, having realized completed intelligent control. For its own advantages, intelligent pneumatic ball valve has been applied in different fields. For example, because of compact structure and reliable sealing, the valve is used for current limiting operation in amount of chemical plants. Features of intelligent pneumatic ball valve: 1. The seat of ball valve has good sealing. The sealing ring made of PTFE and other...

Electric high pressure gate valve uses flange connection, a kind of the whole direct casting valve. Electric high pressure gate valve is mainly used for water, oil and overheating steam pipes whose pressure below PN16.0MPa. Bonnet connection is used in central section, still having good sealing performance under the working conditions of high temperature and high pressure. Upper layer of sealing face of electric high pressure gate valve is bead welded by cemented carbide. The pure metal layer is...

Insulation ball valve and flanged gate valve are the same category of valve. Due to good heat preservation and cold insulation, insulation ball valve has been widely applied in chemical engineering, metallurgy, pharmacy and food, having high popularity on the market. Proper installation cannot only protect insulation ball valve from abrasion, but also can improve its efficiency. Installation steps of insulation ball valve: 1. Take off protective caps at the two ends of flange. The valve...

Silent check valve is a kind of automatic valves whose disc can open or close automatically based on fluid media inside pipes flowing. The disc of valve rotates with the centerline of body. Under the pressure of media in one direction, the disc opens; when media flow reversely, the disc closes automatically, blocking media inside pipes flowing. Silent check valve has light volume and weight, convenient for transportation and installation while it is not suitable for media having granular solid or...

Hard seal eccentric semi-ball valve uses the common path of eccentric body, eccentric ball, seat and stem for centring when they make rotational motion. It is tighter during closing to realize sealing. The ball is separated from seat completely, eliminating the abrasion of sealing ring and overcoming the abrasion between conventional seat and body. Nonmetal elastic materials are implanted into metal seat so that the metal face of seat can be protected. The valve is quite suitable for fiber, tiny...

Power station welding gate valve is used for pipes of high temperature high pressure water, oil or over-heating steam in thermal power plant, petrochemical industry and metallurgy. The valve has the advantages of wearing resistance, temperature resistance, corrosion resistance and long service life. Power station welding gate valve has the following features. 1. The shell is cast by using precise technology, having smooth appearance, uniform microstructure and meeting the requirement of low...

For energy conservation, noise reduction, low fluid resistance, rapid on-off, axial flow check valve has been widely used for oil and gas transmission pipeline. In China, for large LNG terminals having been built or under construction, axial flow check valve is installed at the position where non-return is required. During design, advancement, reliability, safety and stability of technology should be taken into consideration. What’s more, damping, shock absorption and energy conservation should...

In recent years, for global gas industry highly developing, LNG has already become an important part of international gas trade. By 2020, LNG will account for 40% of gas trade volume and 15% of gas consumption. Gas liquefying plant should be equipped with low temperature ball valve. So, the valve is popular. Under the pressure of media, the floating ball of low temperature ball valve may displace definitely and adpress the sealing face of outlet, maintaining the sealing of outlet. Low...

Check valve at the outlet of centrifugal pump is used to prevent water hammer caused fluid backflow in outlet pipeline from damaging impeller inside pump. Check valve is mainly used to prevent fluid from flowing back which makes pump reverse and cause damage. And it also protects other storage tanks from being damaged by fluid backflow. According common situation of pump, choosing check valve for outlet of centrifugal pump should follow these tips: 1. For pipeline having low...