Description of the hottest metal Rotameter

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Description of metal rotameter

the flow marked in the above table is the maximum flow, and the range is 10:1, for example: 15mm diameter, the flow rate of the lowest gear is 0.0025 ~ 0.025 cubic meters/hour

note: the gas flow is the flow under the standard state (pressure 760mmhg, temperature 20 ℃)

for the small caliber micro flow type metal rotameter, it is not necessary to consider the requirements of the front and rear straight pipe sections

structure and basic principle flowmeter

Zhang Zhi said that the flow detection element of the metal rotameter is composed of a vertical conical tube that expands from bottom to top and a float group that moves up and down along the axis of the conical tube. The working principle is as shown in Figure 1. When the measured fluid passes through the annular gap 3 formed by cone tube 1 and float 2 from bottom to top, the differential pressure between the upper and lower ends of the float generates the rising force of the float. When the lifting force received by the float is greater than the weight of the float immersed in the fluid, the float rises, the annular gap area increases, the fluid flow rate at the annular gap immediately decreases, the differential pressure between the upper and lower ends of the float decreases, and the rising force acting on the float also decreases, Until the lifting force is equal to the weight of the float immersed in the fluid, the float will be stabilized at a certain height from the raw material to the operation of the staff. There is a corresponding relationship between the height of the float in the cone tube and the flow through it. The basic equation of the volume flow Q of the automatic instrument is:

when the float is a non solid core hollow structure (load adjustment amount), the flow coefficient of the instrument in the formula

varies according to the shape of the float

when the measured fluid is a gas, the gas expansion coefficient is usually ignored because the correction amount of this coefficient is very small, and it has been included in the flow coefficient through verification. If it is a liquid =1

△ f circulation annular area, m2

g local gravity acceleration, m/s2

vf float volume, if there is an extension, it should also include, m3

f float material density, kg/m3

density of the measured fluid, such as the density of the gas on the cross section upstream of the float, kg/m3

ff cross sectional area at the working diameter (maximum diameter) of the float, m2

gf float mass, kg

the relationship between the circulating annular area and the float height is shown in formula (3). When the structural design has been determined, D and are constant. In the formula, there is a quadratic term of H. generally, this nonlinear relationship cannot be ignored. Only when the cone angle is very small, it can be regarded as approximately linear

m2 (3)

where D is the maximum diameter (i.e. working diameter) of a challenge float, m

h the rising height of the float from the point where the inner diameter of the cone tube is equal to the maximum diameter of the float, m

conical angle of conical tube

a, B constants

Nantong Guoyi Automation Instrument Co., Ltd. () is a high-tech enterprise integrating R & D, production and sales. Its main products include electromagnetic flowmeter, electromagnetic heat meter, steam flowmeter, metal rotameter, ultrasonic flowmeter and various throttling devices

the company is located in Nantong Gangzha Economic Development Zone, with strong technical force. It cooperates with colleges and universities of Nantong University and has established the State Key Laboratory of fluid mechanics; With product development centers in Shanghai and Wuxi, Jiangsu Province, there are a group of senior technical talents who have infiltrated the flow meter industry for many years, focusing on product innovation and development. The company has a professionally designed and customized flowmeter production line with leading level, advanced production capacity, and domestic advanced detection devices and calibration systems to ensure that the products produced have high performance and high reliability

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