German HARRIS valve HARRIS model HARRIS price

With a constant pressure differential across the HARRIS valve, the flow rate of a standard valve changes little when the opening degree varies over a wide range. However, at a certain opening degree, the flow rate changes sharply, indicating poor regulation performance. A control valve is a valve that 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 divided into manual control valves and automatic control valves. Manual and automatic control valves come in many types with different regulation performances. Automatic control valves include self-operated flow control valves and self-operated differential pressure control valves.

HARRIS 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 action. To ensure no leakage at the connection, lead oil, hemp, and PTFE raw material tape are often used for filling; among these, PTFE raw material tape is increasingly widely used. This material has excellent corrosion resistance, provides an excellent sealing effect, and is convenient to use and store. During disassembly, it can be removed intact because it is a non-adhesive film, which is much superior to lead oil and hemp. 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 action.

HARRIS valve sealing requirements

The sealing performance of a valve refers to the ability of its various sealing parts to prevent medium leakage. It is the most important technical performance indicator of a valve. There are three sealing parts 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 packing box; and the connection area between the valve body and the valve cover. Leakage at the first location is called internal leakage, also known as incomplete closure, which affects the valve's ability to cut off the medium. For shut-off valves, internal leakage is not allowed. 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 can even cause accidents in severe cases. For flammable, explosive, toxic, or radioactive media, external leakage is strictly prohibited; therefore, valves must have reliable sealing performance.

HARRIS valve advantages

The electric ball valve structure consists of only a few components, saving material usage; it is small in size, light in weight, has small installation dimensions, requires low driving torque, is simple and agile to operate, and can be quickly opened or closed by rotating just 90°; it also has good flow regulation efficiency and tight sealing characteristics. In applications with large and medium diameters and medium to low pressures, the electric ball valve is the dominant valve type. When the electric ball valve is in the fully open position, the thickness of the disc is the resistance to the medium flowing through the valve body, so the pressure drop generated by passing through this valve is very small, giving it 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 adapt to higher working temperatures, while elastic sealing has the disadvantage of being limited by temperature. 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 not only widely used in general industries such as petroleum, gas, chemical, and water treatment, but also in the cooling water systems of thermal power stations. Common electric ball valves include wafer-type electric ball valves and flanged electric ball valves. Wafer-type electric ball valves connect the valve between two pipe flanges using double-headed bolts. Flanged electric ball valves have flanges on the valve, connecting the flanges at both ends of the valve to the pipe flanges with bolts. 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 stiffness 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 can achieve intelligent control, quickly opening or closing the pipeline, and effectively controlling and managing the pipe network.

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