Flow meter measurement knowledge

1. What is traffic? What are the two categories?

Flow rate is the amount of fluid flowing through a section of a pipe per unit time. It is divided into volume flow and mass flow.

2, with the orifice plate to measure the flow, why is it reasonable to install the orifice plate in front of the regulating valve?

In the theoretical deduction of the flow measurement of the throttling device, there are two assumptions in theory, that is, the fluid flow is continuous, and the law of conservation of energy is observed during the fluid flow process, which tells us that the orifice plate can not be installed in the place where the gas and liquid coexist, so as not to increase the measurement error. Some fluids (such as liquefied hydrogen) after the regulation of cutting pressure, sometimes there will be part of the vaporization, the formation of two coexistence, therefore, the flow hole plate should be installed as far as possible before the regulation of cutting, this installation is reasonable.

3. Requirements for straight pipe section of hole plate installation?

Requirements for the straight pipe section of the hole plate installation: the standard hole plate works in turbulent condition, the straight pipe section in front of the hole plate is generally required to be 10D, and the straight pipe section after the hole plate is generally required to be 5D. In order to measure correctly, the straight pipe section in front of the hole plate is preferably 30~50D, especially when there is a pump or regulating valve in front of the hole plate.

4. What are the requirements for hole plate installation?

(1) The front end face of the throttling part should be perpendicular to the pipeline axis, and the non-verticality should not exceed 1°;

(2) the orifice of the throttling part should be concentric with the pipeline;

(3) The sealing gasket for clamping the throttling part shall not burst into the inner wall of the pipeline;

(4) The newly installed pipe must be installed after "purging";

(5) The connection of each pipe section and pipe fitting of the throttling device shall not have any pipe diameter mutation.

5, the role of the throttling device?

Is to cause a local contraction of the flow rate, resulting in a pressure difference. And the larger the flow rate, the greater the pressure difference generated before and after the throttle device, so the size of the fluid flow can be measured by measuring the pressure difference.

6, What are the five pressure methods of the hole plate?

1) Angle pressure method 2) flange pressure method 3) Theoretical pressure method 4) diameter distance pressure method 5) pipe pressure method