Flow transmitter provided with double differential pressure sensors and pressure difference measurement method

Abstract

The invention discloses a differential pressure type flow transmitter provided with two differential pressure sensors. The flow transmitter is characterized in that a piston consisting of a cylinder and a head flange is arranged in an outer shell; a big cavity is partitioned into high and low pressure regions by the head flange of the piston; the piston is provided with an elastic component; the outer shell is provided with measurement holes of a high pressure difference measurement module (A) and a low pressure difference measurement module (B); high and low pressure measurement holes of thehigh pressure difference measurement module (A) ensure that two dead centre positions for compression and ejection of the elastic component are positioned in high and low pressure regions respectively; when the elastic component is not compressed, the high pressure measurement hole of the low pressure difference measurement module (B) is connected with the high pressure region; the elastic component is compressed to the dead centre position, the piston is moved to the end and the connecting channel is cut off. The transmitter can automatically switch the working channel of the low pressure difference measurement module (B) according to the pressure difference size so as to change the operating state of the low pressure difference measurement module (B) and protect the low pressure difference module; and meanwhile, the measurement range can be expanded by effectively using two pressure difference measurement modules.

Description

technical field [0001] The invention relates to a flow measuring device, in particular to a flow transmitter using high and low double pressure difference sensors. Background technique [0002] The differential pressure flowmeter ranks first in the list of flowmeters due to its mature technology, simple structure, stability and reliability, and wide application range. However, the fundamental problem with this type of differential pressure flowmeter is the narrow measurement range. Because the flow rate has a square function relationship with the pressure difference, if the flow rate is 100 times the minimum value, then the pressure difference is 10,000 times the minimum value, which limits the measurement range. Usually 1:4 or 1:10 is already great now. According to the publication of the self-adaptive differential pressure flowmeter in "Flowmeter Information Network", it is said that it can achieve 1:20. However, in actual engineering, the required flow range is often r...

AI Technical Summary

Problems solved by technology

However, the existing differential pressure flowmeter cannot meet the wide-range measurement requirements; if two differential pressure sensors are used, a high-pressure differential sensor is used for large flow rates and a low-pressure differential sensor is used for small flow rates, of course the range can be greatly expanded, but the low differential pressure The sensor cannot withstand the high pressure difference condition, so two sensors can only be installed on two pipes, and then use the automatic control scheme to use the pipe with the large pressure difference sensor when the flow is large, and install the low pressure difference sensor when the flow is small pipeline

This is an expensive and complicated project

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