The key to the flow and flow rate of the valve is the diameter of the valve, and it is also related to the frictional resistance of the valve structure to the medium.
The total flow area of the valve is directly related to the flow rate and flow rate, and the flow rate and flow rate are two interdependent quantities. When the flow rate is necessary, the flow rate is large, the total area of the flow channel can be smaller; the flow rate is small, the total flow channel area can be larger. On the contrary, the larger the total area of the flow channel, the smaller the flow rate; the smaller the total area of the flow channel, the larger the flow rate.
The flow rate of the medium is large, and the valve diameter can be smaller, but the frictional resistance is very damaged, and the valve is easily damaged. The flow rate is large, which will cause electrostatic effect to the flammable and explosive medium, resulting in risks; the flow rate is small, the efficiency is low, and it is not economical. For high viscosity and flammable and explosive media, a smaller flow rate should be used. Oils and liquids with high viscosity select the flow rate according to the viscosity size, usually 0.1~2m/s.
Normally, the flow rate is known and the flow rate can be determined empirically. The nominal diameter of the valve can be calculated from the flow rate and flow.
The valve diameter is the same, its structure is different, and the frictional resistance of the fluid is also different. Under the same standard, the larger the friction resistance index of the valve, the greater the reduction of the fluid according to the flow rate and flow of the valve; the smaller the friction resistance index of the valve, the less the fluid will drop according to the flow rate and flow of the valve.
The use of valve diameter should fully consider the production and processing precision and dimensional error of the valve, as well as other factors. The valve diameter needs to have a certain margin, usually 15%. In specific work, the valve diameter depends on the diameter of the process pipeline.