The flowmeter weighing impulse flowmeter that measures the flow using the impulse theorem is used to measure the flow rate of the granular solid medium, and is also used to measure the flow rate of the mud, the crystalline liquid, and the abrasive. Flow measurement ranges from a few kilograms per hour to nearly 10,000 tons. The typical instrument is a horizontal force-separated impulse flowmeter. The measurement principle is that when the measured medium falls freely from a certain height h to a detection plate with a tilt angle, an impulse is generated, and the horizontal force component of the impulse is proportional to the mass flow rate. Measuring this horizontal component can reflect the mass flow.
The electromagnetic flowmeter is made by applying the electric conductor to generate an induced electromotive force in a magnetic field, and the induced electromotive force is proportional to the flow rate, and is measured by measuring the electromotive force to reflect the flow of the pipeline. Its measurement accuracy and sensitivity are high. Industrially used to measure the flow of water, slurry and other media. The maximum diameter can be measured up to 2m, and the pressure loss is extremely small. However, media with low conductivity, such as gas and steam, cannot be used.
The electromagnetic flowmeter has a high cost, and the signal is susceptible to external magnetic field interference, which affects the wide application in industrial tube flow measurement. To this end, the product is constantly improving and updating, to the development of computer.
Fourth, the liquid turbine flowmeter put into operation the opening and closing sequence
1. The sequence of opening and closing of the operation
For flow sensors without a bypass line, first open the flow sensor upstream valve at a medium opening and then slowly open the downstream valve. Run at a small flow rate for a period of time (eg 10 minutes), then fully open the upstream valve, then open the large downstream valve opening to adjust to the required normal flow.
The flow sensor equipped with the bypass pipe first opens the bypass pipe valve to open the upstream valve at a medium opening degree, slowly opens the downstream valve, and closes the opening of the small bypass valve to make the instrument run for a period of time with a small flow rate. Then fully open the upstream valve, fully close the bypass valve (to ensure no leakage), and finally adjust the downstream valve opening to the required flow.
2. Activation of low temperature and high temperature fluids
The low-temperature fluid pipeline should drain the water in the pipeline before the flow, and then run for 15 minutes at a small flow rate, and then gradually increase to the normal flow. Slow down when stopping, so that the pipe temperature and ambient temperature are gradually approaching. High temperature fluid operation is similar to this.
In the case of small flow metering, the film surface ratio is the largest, the Roots flowmeter is second, and the turbine flowmeter is the smallest. The initial flow performance of the volumetric flowmeter should be superior to the velocity flowmeter. For industrial and commercial users with large total gas consumption and low heat load for each gas, the volumetric flowmeter, ie, the membrane meter and the Roots flowmeter, should be preferred to meet the flowmeter requirements of a single burner when used alone. It can also meet the measurement requirements of the maximum flow rate when all burners are used at the same time.
Not all industrial and commercial users can solve the measurement problem by selecting a volumetric flowmeter with a larger range. The volumetric ratio of the volumetric flowmeter is limited, and it is impossible to increase without limit. The selection of the flowmeter cannot be solved. This kind of user has a measurement problem. When the user only uses a single device for gas, or when operating at low flow rate, the initial flow rate and minimum flow rate of a single flow meter may not meet the minimum flow rate requirement. A single large flow meter cannot measure low gas consumption, which will result in Large supply and marketing differences.