Tips for selecting control valves for low flow rates
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In addition to general industrial process control, there are many applications in laboratories and pilot plants that require the control of extremely low flow rates. Such low flow rates result in a leakage rate that is even lower than that of ordinary valves; therefore, standard mechanical processing and conventional manufacturing methods cannot ensure satisfactory performance in such cases. The only solution is to experimentally calibrate the flow characteristics of each valve, so as to have specific, accurate values representing the actual flow rate. Structural form: Generally, there are two methods to address low-flow control issues: (1) using special valve internals within a standard valve body. This method typically achieves a Kv value of around 0.03. Using special valve internals in standard valve bodies offers good economic benefits and scalability, as it reduces the need for special valve bodies and actuators as spare parts, while also facilitating an increase in flow rates in the future (only the standard valve internals will need to be replaced). (2) Special control valves designed for ultra-low flow rate regulation can achieve a Kv value of around 0.001, exhibit nearly linear characteristics, are forged as a single unit, and feature a compact structure with low weight.
We have recently carried out a pilot test that involved the use of control valves with very low flow rates; please provide information on the selection criteria for such valves as well as details on manufacturers that offer them.
We have pressure regulators specifically designed for use in laboratory analysis; they are from the American GO brand. These regulators allow for very low flow rates, and they serve to precisely adjust the outlet pressure in analytical instrument systems. Thanks to the large area of the diaphragm that senses pressure, as well as the compact valve seat assembly, these valves can easily maintain pressure below 10 inches of water column, with a CV of 0.004. There is also a sophisticated pressure relief valve designed to allow users complete flexibility in their applications, enabling instrumentation engineers to select the most appropriate operational parameters for precise fluid systems. In laboratories and chromatographic analysis, air pollution testing, as well as in various industrial processes and laboratory instruments, the regulation of flow rate and pressure can now be accomplished easily and cost-effectively. Small internal spaces free from residual media allow high-sensitivity instrument systems to remain clean and easy to operate. Standard stainless steel diaphragms effectively prevent impurities from entering the fluid system. This series of valves offers excellent stability in terms of pressure and flow rate, especially in highly demanding applications such as gas chromatography analysis, where it provides the best stability despite temperature changes. If necessary, please contact Mr. Liu at 021-54439561!