Check Valve According to its structure
Check valve is to rely on the flow of the media itself and automatically open, close the valve, used to prevent the media back valve.
Check valve according to its structure can be divided into:
First, the lift check valve: valve flap along the vertical center of the valve body sliding check valve, lift check valve can only be installed in the horizontal pipe, high pressure small diameter check valve on the valve can be used ball The The shape of the valve body of the lift check valve is the same as that of the shut-off valve (which can be used with the globe valve), so its fluid resistance coefficient is large.
Second, the swing check valve: valve flap around the valve seat outside the pin rotation of the check valve, swivel check valve application is more common.
Third, the disc check valve: valve flap around the valve seat rotation of the check valve. Disc-type check valve structure is simple, can only be installed in the horizontal pipe, the seal is poor.
Fourth, the pipeline check valve: valve flap along the valve center line sliding valve. Pipeline check valve is a new type of valve, its small size, light weight, processing technology is good, is one of the direction of development of the check valve. But the fluid resistance coefficient is slightly larger than the swivel check valve. In the operational efficiency and energy saving, the use of automatic control valve is an indispensable part of the traditional industry commonly used manual valve, pneumatic valve, the installation cost and efficiency are less than the electric valve.
Industry sources said that the valve in the industrial process, mostly used to control the flow of various fluids and flow, such as water, oil, chemical liquids, according to the parameters of temperature, pressure and flow. The factory commonly used control valve with pressure relief valve, pneumatic temperature control valve, solenoid valve temperature system, proportional control valve temperature control system, temperature control valve, and several other types. In the selection of various types of automatic valve, should consider the type of heat, the required accuracy, control valve quality, pressure drop, flow and its structure, failure rate, manufacturers credit and after-sales service and other factors in order to achieve economic and practical purposes.
In terms of the product itself, the electric valve has the advantages of easy assembly, low failure rate and meet the needs of the industry automation, the industry is more cost-effective choice. Because the use of the traditional traditional pneumatic valve, will inevitably have piping, solenoid valves and compressors to match, and electric valve is a motor-driven, easy installation and easy, and the installation of electric valve with the original control of the original line can save other Cost of expenditure. In addition, the motor-driven way to open and close more smoothly, no instantaneous impact is too large shortcomings, failure rate can be significantly reduced.
Many people think that the electric valve expensive, the use of high cost, it is not true, if the overall calculation, the traditional valve to add a lot of accessories and pipe installation, the price is not dominant, but to bear more maintenance costs. 1 Corrosion resistant materials are selected according to corrosive media
In the actual production, the corrosion of the medium is very complicated. Even if the valve material is used in a medium, the medium's concentration, temperature and pressure are different, and the medium is not corroded with the material. , The corrosion rate of about 1 to 3 times the medium concentration on the valve material corrosion great impact, such as lead in the small concentration of sulfuric acid, the corrosion is very small, when the concentration exceeds 96%, the corrosion increased sharply, while the carbon steel, In the sulfuric acid concentration of about 50% when the most serious corrosion, when the concentration increased to 6% or more, the corrosion but a sharp decline in the concentration of 80% or more concentrated nitric acid in the corrosive strong, but in the low concentration of nitric acid But the corrosion of dilute nitric acid is very strong, but more than 95% of the concentrated nitric acid corrosion is aggravated.
From the above cases can be seen, the correct choice of valve materials should be based on specific circumstances, analysis of various factors affecting the corrosion, according to the relevant anti-corrosion manual selection of materials.