German VAI valve VAI model VAI price

With a constant pressure differential across the VAI valve, the flow rate of a standard valve changes little when the opening varies over a wide range. However, at a certain opening, the flow rate changes sharply, indicating poor regulation performance. A control valve adjusts the valve core stroke according to the direction and magnitude of the signal to change the valve's resistance coefficient, thereby achieving flow regulation. Control valves are classified into manual and automatic types. Both manual and automatic control valves come in various types with different regulation performances. Automatic control valves include self-acting flow control valves and self-acting differential pressure control valves.

VAI valve connection method: threaded connection

This is a simple connection method, commonly used for small valves. It is divided into two cases: 1) Direct sealing: internal and external threads directly provide the sealing effect. To ensure no leakage at the connection, lead paste, hemp yarn, and PTFE raw tape are often used for filling; among these, PTFE raw tape is increasingly widely used. This material has excellent corrosion resistance, provides superior sealing, and is convenient to use and store. During disassembly, it can be removed intact as it is a non-adhesive film, making it far superior to lead paste and hemp yarn. 2) Indirect sealing: the tightening force of the thread is transmitted to the gasket between the two planes, allowing the gasket to provide the sealing effect.

VAI valve sealing requirements

The sealing performance of a valve refers to the ability of its sealing parts to prevent medium leakage. It is the most important technical performance indicator of a valve. There are three sealing locations in a valve: the contact area between the two sealing surfaces of the closing member and the valve seat; the mating area between the packing, the valve stem, and the stuffing box; and the connection area between the valve body and the bonnet. Leakage at the first location is called internal leakage, commonly known as incomplete closure, which affects the valve's ability to cut off the medium. For shut-off valves, internal leakage is not permitted. Leakage at the latter two locations is called external leakage, where the medium leaks from inside the valve to the outside. External leakage causes material loss, environmental pollution, and may even lead to accidents in severe cases. For flammable, explosive, toxic, or radioactive media, external leakage is strictly prohibited; therefore, valves must have reliable sealing performance.

VAI valve advantages

The electric ball valve structure consists of only a few components, resulting in low material consumption. It features a compact size, light weight, small installation dimensions, and low driving torque. As shown in the electric ball valve structure diagram, it is easy and agile to operate, requiring only a 90° rotation for quick opening and closing. It also offers good flow regulation efficiency and tight sealing characteristics. In applications involving large to medium diameters and medium to low pressures, the electric ball valve is the dominant valve type. When the electric ball valve is fully open, the disc thickness is the resistance to the medium flowing through the valve body, resulting in a small pressure drop and thus good flow control characteristics. Electric ball valves have two sealing types: elastic sealing and metal sealing. For elastic sealing valves, the sealing ring can be embedded in the valve body or attached to the periphery of the disc. Valves with metal sealing generally have a longer service life than those with elastic sealing, but it is difficult to achieve complete sealing. Metal sealing can withstand higher operating temperatures, whereas elastic sealing has temperature limitations. If an electric ball valve is required for flow control, it is important to accurately select the valve size and type. The structural principle of the electric ball valve is particularly suitable for manufacturing large-diameter valves. Electric ball valves are widely used not only in general industries such as petroleum, gas, chemical, and water treatment, but also in cooling water systems of thermal power stations. Common electric ball valves include wafer-type and flanged-type electric ball valves. A wafer-type electric ball valve is connected between two pipe flanges using double-headed bolts. A flanged-type electric ball valve has flanges on the valve, which are bolted to the pipe flanges at both ends. The strength performance of a valve refers to its ability to withstand medium pressure. As a mechanical product subjected to internal pressure, a valve must have sufficient strength and rigidity to ensure long-term use without rupture or deformation. A pneumatic ball valve consists of a ball valve equipped with a pneumatic actuator. Pneumatic actuators are divided into double-acting and single-acting types. Controlled by a solenoid valve, they realize the switching action of the ball valve. Pneumatic ball valves enable intelligent control, rapid opening or closing of pipelines, and effective control and management of the pipeline network.

Weidou Intelligent Technology specializes in selling German VAI valves, VAI safety valves, VAI globe valves, VAI control valves, VAI solenoid valves, VAI ball valves, VAI proportional valves, VAI diaphragm valves, VAI butterfly valves, VAI hydraulic transmission valves, VAI check valves, VAI pressure reducing valves, VAI relief valves, VAI sequence valves, VAI balance valves, VAI throttle valves, VAI directional control valves. Original imports from Germany. Welcome customers to inquire and order.