Diffusion tube type rectangular flow meter

Abstract

The invention relates to a flow meter, in particular to a diffusion tube type rectangular flow meter. The diffusion tube type rectangular flow meter comprises a measurement tube and body flanges welded to the two ends of the measurement tube, and a pair of pressure tapping flanges are welded to the measurement tube in the axial direction. The diffusion tube type rectangular flow meter is characterized in that a trapezoid throttling element is arranged at the position, below the pressure tapping flanges, in the measurement tube; the cross section of the trapezoid throttling element is in a circular notch shape, the front projection is in the inverted trapezoidal shape with the big upper portion and the small lower portion, two acute angles of the trapezoid are 15-60 degrees and 7-30 degrees respectively, and a negative pressure sampling hole is formed in the center of the throat. The diffusion tube type rectangular flow meter is unique in structure, high in accuracy, good in linearity, high in long-term working stability and reliability, long in service life, high in pressure recovery and small in perpetual pressure loss.

Description

technical field [0001] The invention relates to a flow meter, in particular to a diffusion tube type rectangular flow meter. Background technique [0002] In the flow measurement automation instrument industry, there are only several conventional differential pressure flowmeters. These structures have many shortcomings, mainly as follows: 1) Low accuracy, poor linearity, long-term working stability and reliability 2) The service life is short; 3) The pressure recovery is slow and the permanent pressure loss is large, such as the standard orifice plate in the traditional throttling device, there are problems such as low accuracy, small range ratio, and large pressure loss; although the pressure of the nozzle and Venturi The loss is small, but the measurement accuracy and turndown ratio are not ideal. [0003] So far there is no device that overcomes the aforementioned drawbacks. Contents of the invention [0004] The purpose of the present invention is to overcome the def...

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Problems solved by technology

[0002] In the flow measurement automation instrument industry, there are only several conventional differential pressure flowmeters. These structures have many shortcomings, mainly as the following: 1) Low accuracy, poor linearity, long-term working stability and reliability 2) Short service life; 3) Slow pressure recovery and large permanent pressure loss, such as the standard orifice plate in the traditional throttling device, there are problems such as low precision, small range ratio, and large pressure loss; although the pressure of the nozzle and Venturi The loss is small, but the measurement accuracy and turndown ratio are not ideal

[0003] There is no device that overcomes the above-mentioned defects so far

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