Plug valve is one of the earliest used valves with simple structure, fast opening and closing and low fluid resistance. Ordinary plug valves are sealed by the direct contact between the finished metal plug body and the valve body, which has the disadvantages of poor sealing, large opening and closing force and easy wear. They can only be used in low (not higher than 1 MPa) and small diameter (less than 100 mm). In order to expand the application range of plug valve, many new structures have been developed. Oil seal plug valve is the most important one. Special grease is injected from the top of the plug body between the taper hole of the valve body and the plug body to form an oil film to reduce the opening and closing torque and improve the sealing performance and service life. Its working pressure can reach 64 MPa, the maximum working temperature can reach 325℃, and the maximum diameter can reach 600 mm. The closing part of the plug valve is a cylinder with holes, which rotates around the axis perpendicular to the channel, so as to open and close the channel. Advantages of plug valve: 1. Easy for frequent operation, quick opening and closing; 2. Low fluid resistance; 3. Simple structure, relatively small volume, light weight and easy maintenance; 4. Good sealing performance; 5. The installation direction is unrestricted, the flow direction of media can be arbitrary; 6. No vibration and low noise. Classification of plug valves: 1. By structure: tight set plug valve, self-sealing plug valve, pressure balance plug valve and oil seal plug valve; 2. By channel: straight plug valve, three-way plug valve and four-way plug valve. The channel of plug valve has many forms. The common straight through type is mainly used to cut off the fluid; Three-way and four-way plug valve are suitable for fluid reversing.

平板闸阀是closi的滑阀ng part is a parallel gate. The closing part can be a single gate disc or a double gate disc with a supporting mechanism between them. The pressing force of the wedge to the valve seat is controlled by the medium pressure acting on the floating wedge or floating valve seat. If it is a double wedge flat gate valve, the support mechanism between the two wedges can supplement this pressing force. Features of flat gate valve: 1. The valve seat adopts O-ring seal and floating valve seat structure with preload, so that the inlet and outlet of flat gate valve are sealed in both directions. The opening and closing torque is only 1/2 of ordinary valves; 2. When fully open, the channel is smooth and straight, the flow resistance coefficient is very small, there is no pressure loss, simple cleaning; 3. The packing structure with self sealing ability is adopted, the sealing performance is more reliable than ordinary graphite packing. In addition, grease is injected into the sealing surface of the packing, the sealing surface meets the zero leakage standard; 4. When the flat gate valve is closed, it can automatically remove the high pressure in the inner cavity to ensure the safety of use; 5. Fully enclosed structure, good protection performance. Flat gate valve is divided into single gate plate and double gate plate. According to the connection mode, it can be divided into butt welded flat gate valve and flange flat gate valve. Features of butt welded flat gate valve: 1. Small fluid resistance and small scouring and erosion of sealing surface by medium; 2. Opening and closing is labor-saving; 3. The flow direction of the medium is unrestricted, no turbulence and no pressure reduction. 4. Simple shape, short structure length, good manufacturing technology and wide application range. Flange flat gate valve is stable and reliable when used in pipeline, Therefore, DERVOS recommends that flange flat gate valve could be used in high pressure pipeline. Features of flange type flat gate valve: 1. The sealing structure of flange flat gate valve is elastic with preload, and the upstream and downstream sealing seats are sealed at the same time. There is always face-to-face seal between the valve seat and the seal; 2. The valve seat has self-cleaning function and is not directly scoured by the air flow during the opening or closing of the valve. The valve seat is made of lubricated and non abrasive materials; 3. The problem of the valve actuator will not affect other parts of the valve, and the maintenance and replacement can be carried out without removing the valve; 4. When the flange flat gate valve is fully opened, the channel is smooth and straight, the flow resistance coefficient is very small, there is no pressure loss, and the pipeline can be cleaned by wool ball.

在中国2022年是虎年。它将不le's expectations that they could be as brave and strong as tigers and keep working hard. DERVOS Annual meeting of 2021 was held in the second working day after the Spring Festival holiday, which is also Valentine's Day, 14th Feb. In the morning, the heads of all departments made work reports. In the work reports, they reviewed the work achievements of the past year. At the same time, the Department's work objectives and work plans for the new year were formulated. Finally, Eric, our general manager summarized and planed the direction of struggle in 2022.The key word is pragmatic and development. Pragmatic means to work steadily, reduce trial and error costs, and carry out work with practical and feasible schemes. In the meantime, go from complexity to simplicity,result oriented, the final goal is to achieve the development. In the evening, the annual work summary came to an end and the annual dinner officially began. This was not only a good time for different departments to get together, but also an opportunity to win big prizes. DERVOS people work hard and also love life. We are grateful to the support of our business partners over the past year. We will continue to improve and provide partners with the most professional support and meticulous service.