Working principle and selection instructions of chromatographic steady flow valve

Steady flow valve in gas chromatographIn gas chromatography analysis, the flow stability of carrier gases (such as nitrogen and helium) directly affects the sample compositionAway from the effect.

The steady flow valve automatically adjusts the valve opening by sensing changes in pressure in front of the column, ensuring a constant flow rate of the carrier gasBy chromatography column. For example, when the resistance of a chromatographic column increases due to temperature changes, the opening of the steady flow valve will increase,Compensate for pressure loss, maintain flow stability, and ensure that the retention time and separation degree of chromatographic peaks remain unchanged.

A steady flow valve is a device used to maintain a stable flow rate of a fluid (gas or liquid), based on its core principleIt is achieved by automatically adjusting the valve opening to counteract the impact of system pressure fluctuations on flow rate. The specific working mechanism is as follows:The diaphragm, valve core, spring and other components form a closed-loop feedback system,Realize stable traffic.The working mechanism of the steady flow valve is based on the principle of pressure feedback control. The built-in elastic diaphragm serves as a pressure sensorComponent, real-time monitoring of fluid pressure changes. When the system pressure fluctuates, the diaphragm undergoes elastic deformation and drivesAdjust the displacement of the valve core. Specifically, when the pressure increases, the valve core automatically reduces the flow cross-sectional area and increasesFluid resistance; When the pressure decreases, the flow area is expanded to compensate for the flow loss, thereby achieving dynamic flowBalance. This process strictly follows the Bernoulli equation and orifice flow formula to ensure the scientific and accurate flow controlAccuracy.