Dervos provides high performance ball valve products, including Trunnion mounted ball valve, Floating ball valve, Welded structure ball valve, Top entry ball valve, Wafer ball valve, Butt treaded socket welding ball valve, and Three way ball valve etc.
Ball valve is used to on/off the medium in pipeline, and widely used in petroleum refining, chemical, electric power, long-distance transportation pipeline, paper making, pharmaceutical, water conservancy, municipal and steel, etc. Special consideration is taken to strength, safety, and resistance to harsh environment during designation. It's suitable for various corrosive and non-corrosive mediums. Different materials may be selected for transportation of water, steam, oil, natural gas, nitric acid, acetic acid, oxidant and urea. Ball valve has compact structure and reliable sealing. Its sealing surface and spherical surface are closed normally which make it resistant to flush erosion from the medium, and easy to operate and repair.
Dervos provides high performance butterfly valve products, including Hard seal and soft seal butterfly valve, triple offset/double offset/centric butterfly valve, Lug type / Wafer type/ Hoop type/ Flanged ended butterfly valve, and three-way butterfly valve etc. Especially our Bi-directional seal butterfly valve can be tested at 1.1 times design pressure with zero leakage at both directions.
Butterfly valve is a kind of valve that takes a disc as closing part (butterfly board) which rotates around the valve axis to achieve opening and closing. The valve is mainly used for cut-off and throttling on pipeline. A plate or disc is positioned in the center of the pipe. The disc has a rod passing through it that is connected to an actuator outside of the valve. Rotating the actuator turns the disc either parallel or perpendicular to the flow. The flow of medium may be controlled by changing deflection angle of butterfly board. Butterfly valve is suitable for pipeline that transports various corrosive, non-corrosive fluids in producer, coal gas, natural gas, liquefied petroleum gas, city gas, hot and cold air, chemical smelting and power environmental protection, building water supply and drainage and other engineering systems for regulating and cutting off medium flow.
Dervos provides high performance check valve products, including Swing check valve, Lifting check valve, Titling check valve, External check valve, and Wafer check valve etc.
Check valve, non-return valve or one-way valve is a kind of mechanical device and a valve, which normally allows fluid (liquid or gas) to flow through it in only one direction. An important concept in check valves is the cracking pressure which is the minimum upstream pressure at which the valve will operate. Typically the check valve is designed for and can therefore be specified for a specific cracking pressure.
Dervos provides high performance gate valve products, including Wedge gate valve, Pressure seal gate valve, Knife gate valve, Flat gate valve and Bellow seal gate valve etc.
Opening and closing part of gate valve is flashboard. Its direction of motion is perpendicular to the direction of fluid. The valve is usually used to cut off medium. The entire flow channel is a straight-through passage when the valve is fully open, and the pressure loss of medium running is minimum. Gate valve is usually divided into several types by seal part mode, such as: wedge gate valve, plate gate valve, parallel 2-flashboard gate valve, wedge 2-flashboard gate valve. Gate valve is usually used under some working conditions in which the valve is not opened or closed frequently, and supports flashboard fully open or fully closed. It's not suitable for adjustment or throttling. Various materials may be selected for transportation of water, steam, oil, natural gas, nitric acid, acetic acid, oxidant and urea.
Dervos provides high performance globe valve products, including API globe valve, DIN globe valve, ANSI bellow seal globe valve, Angle globe valve, Y type globe valve, and Pressure seal globe valve etc.
Globe valve is a kind of valve with close part making a linear motion along the center line of valve seat. As the opening and closing stroke of valve stem is relatively short, with reliable cut-off function, the change of valve seat orifice and stroke of valve clack are proportional, the valve is really suitable for flow regulating. It may be used for cuting off or regulating as well as throttling of fluid pipeline for city water, sewage, construction, food, electric power, medicine, metallurgy and textile.
Dervos provides plug valve products of high performance, including Inverted pressure plug vale, Sleeve-type soft sealing plug valve, Jacket plug valve, Orbit plug valve, Flange-connection lifting plug valve, 3-way and 4-way plug valve etc.
Plug valves are the valves with cylindrical or conically tapered "plugs" which can be rotated inside the valve body to control flow inside the valve. The plugs in plug valves have one or more hollow passageways going sideways through the plug, so that fluid can run through the plug when the valve is open. Plug valves are easy-operated and usually economical.