Questions about turbine flowmeters

Turbine flowmeters do not display the flow rate; they only show the cumulative value over a certain period of time. Without a corresponding system for conversion, it is not possible to obtain the flow rate directly from the flowmeter. The standard conditions can be estimated based on operational readings and values such as pressure and temperature over a certain period of time, from which the flow rate can then be calculated (this is not accurate). To accurately measure the instantaneous flow rate, a flow computer is still necessary.

Working principle: As the fluid flows through the sensor housing, the blades of the impeller are at an angle to the flow direction; the force exerted by the fluid on these blades generates a torque that overcomes the frictional torque and fluid resistance, causing the blades to rotate. Once the torques are in balance, the rotation speed stabilizes. Under certain conditions, this speed is proportional to the flow rate. Due to the magnetic properties of the blades, they find themselves within the magnetic field of the signal detector (which consists of permanent magnets and coils). As the rotating blades cut through the magnetic field lines, they periodically change the magnetic flux in the coils, thereby inducing electrical pulse signals at the ends of the coils. These signals are amplified and shaped by an amplifier, resulting in continuous rectangular pulse waves of a specific amplitude. These waves can be transmitted over long distances to display instruments, which then show the instantaneous flow rate and cumulative volume of the fluid. Within a certain range of flow rates, the pulse frequency f is proportional to the instantaneous flow rate Q of the fluid passing through the sensor. The flow rate equation is: Q = 3600×f/k. Where: f – pulse frequency ； 　　k — the meter coefficient of the sensor, given in the calibration sheet. If it is assumed that the unit Q = 3.6×f/k, where Q represents the instantaneous flow rate of the fluid (under operating conditions) ； 　　3600——Conversion factor. 　　The meter coefficient for each sensor is filled in by the manufacturer on the calibration certificate; by entering this k-value into the accompanying display instrument, it is possible to show both the instantaneous flow rate and the cumulative total volume. I’m not quite sure; I just want to learn about it a bit

If the operating pressure at your site is below the minimum required pressure for the gas turbine flow meter, or if the actual flow rate is below the minimum flow rate specified by the meter, or if impurities in the gas cause the impeller to stop rotating, this will result in no flow reading. We often encounter this problem. For low-pressure gases, it is recommended to use gas ultrasonic flow meters at http://www.shakic.com/cp/product4.htm or thermal mass flow meters at http://www.shakic.com/cp/product3.htm