V-Cone Flow Meter Measurement Product Overview

V-cone flowmeter is widely used to measure high-temperature and complex industrial control media. It is very suitable for various dirty and corrosive special media such as gas and liquid such as steam, coal gas, nitrogen, sewage, etc.

1. Measurement principle:

V-cone flowmeter is a differential pressure flowmeter. Flowmeters designed based on the differential pressure principle have been used for more than 100 years. The differential pressure flowmeter is based on the energy conversion principle in the sealed pipeline, that is, for stable fluids, the pipeline pressure is inversely proportional to the square root of the medium flow rate in the pipeline: the pressure will decrease as the speed increases. When the medium approaches the cone, its pressure is P1. When the medium passes through the throttling area of ​​the cone, the speed will increase and the pressure will decrease to P2. Both P1 and P2 are led to the differential pressure transmitter connected to the back through the pressure tapping port of the cone flowmeter. When the flow rate changes, the differential pressure value between the two pressure tapping ports of the cone flowmeter will increase or decrease. When the flow rate is the same, if the throttling area is large, the differential pressure value generated is also large. The β value is equal to the throttling area of ​​the cone divided by the cross-sectional area of ​​the inner diameter of the pipeline (which can be converted into the diameter ratio between the two).

2. Features:

The characteristics of traditional differential pressure instruments are based on ideal flow conditions; in fact, this condition does not exist at all in real applications. Any changes in the pipeline layout, such as elbows, valves, reductions, expansions, pumps, tees, etc., will destroy the fully developed flow. It is difficult for general flow meters to obtain correct measurement values ​​in disturbed flows, and V-cone flowmeters overcome these shortcomings. Under extremely harsh installation conditions, such as there are two elbows upstream that are not on the same plane and are very close to the cone, the V-cone can also make the velocity distribution flat and symmetrical, thereby ensuring measurement accuracy. Since the throttling edge of the V-cone flowmeter is an obtuse angle, a boundary layer is formed during flow, causing the fluid to leave the throttling edge. The boundary layer effect prevents dirty fluids from wearing the throttling edge, and its value remains unchanged for a long time. Therefore, there is no need for repeated calibration, and it has long-term stability. It significantly improves the limitations of traditional differential pressure flowmeters, improves accuracy and repeatability, and has almost no straight pipe section requirements during installation. It has a self-cleaning function and is suitable for dirty media that are prone to scaling, and gas-liquid measurements.

3. Product classification and structure:

According to the product supply range and output signal, V-cone flowmeter can be divided into 3 categories:

1. V-cone flow sensor

Only provides the formation part of differential pressure signal (throttling device and pipeline), does not provide differential pressure transmitter and flow display part, and the output signal is differential pressure. Other configurations are made by the user.

2. V-cone flow transmitter

It consists of V-cone flow sensor and differential pressure transmitter. There are two structures: split installation and integrated installation.

The split V-cone flow transmitter consists of independent V-cone flow sensor and differential pressure transmitter. The connection of the pressure pipe between the V-cone flow sensor and the differential pressure transmitter is completed by the user. The integrated installation means that the differential pressure transmitter and the V-cone flow sensor are connected as one when the product leaves the factory. After the user purchases the integrated V-cone flow transmitter, the pressure pipe does not need to be connected when using it. However, it must be equipped with the corresponding flow integrator, pressure transmitter and temperature transmitter.

3. V-cone flowmeter has two structures: split installation and integrated installation.

The split installation is composed of independent V-cones, differential pressure, pressure, temperature transmitters, flow calculators, stop valves and other parts. The connection combination between the parts is completed by the user. There are two types: explosion-proof and ordinary.

4. In order to ensure accurate measurement, the installation location and method must be selected correctly.

1. Requirements for bypass pipes:

In order to ensure that the normal use of the medium is not affected during the maintenance of the flowmeter, cut-off valves (stop valves) should be installed on the front and rear pipes of the flowmeter, and bypass pipes should be set up. The flow control valve should be installed downstream of the flowmeter. When the flowmeter is in use, the stop valve installed upstream must be fully opened to avoid unstable flow of the fluid in the upstream part.
2. Requirements for the external environment:

V-cone flowmeters are best installed indoors. If they must be installed outdoors, sun protection, rain protection, and lightning protection measures must be adopted to avoid affecting the service life.