Can liquid turbine flow meters measure a high viscosity medium?

The so-called liquid turbine flowmeter is a relatively precise flow measurement and detection instrument. As the name suggests, the liquid turbine flowmeter can only measure liquid media. The instrument is widely used in chemical, petroleum, metallurgy, water treatment, scientific research, environmental protection and other fields. Liquid turbine flowmeter with sanitary fittings can also be used in the pharmaceutical field.

Turbine mass flow meter overview

Turbine flowmeter is a kind of velocity type flowmeter. It is one of the most widely used measuring instruments due to the wide application industry. The cost is moderate. It is very suitable for medium speed, stable speed, clean medium and low viscosity fluid. It can measure the flow rate of liquids, gases and vapors in pipelines, such as chemicals, water, cryogenic liquids, air, natural gas and other industrial gases. 

Compared with the higher precision turbine flowmeter, it can also measure hydrocarbons including natural gas trade metering. In addition, it can also be used in the water, petroleum and chemical industries. Water applications include distribution systems within and between water areas. Petroleum applications include custody transfer of hydrocarbons. Other applications can be found in the food and beverage and chemical industries.

1. Turbine flowmeters are generally only used for low-viscosity single-phase fluids

Through practical application and verification, when the turbine flowmeter measures low-viscosity medium, its meter coefficient hardly changes with the change of flow. When the viscosity of the measured medium increases, the linearity of the turbine flowmeter will become poor. The instrument coefficient will also change greatly with the change of flow, and it is difficult to achieve the due measurement accuracy. When the measured medium is a gas-liquid two-phase flow, the flow rate of the medium will become very unstable, resulting in a large measurement error.

2. The medium fluid measured by the turbine flowmeter should be in a turbulent state

According to the flow characteristics of the turbine flowmeter, when the medium is in laminar flow state, the meter coefficient changes greatly with the change of flow rate, and when the medium is in turbulent flow state, the meter coefficient hardly changes with the change of flow rate. In order to ensure the measurement accuracy of the turbine flowmeter, the measured medium should be in a turbulent state.

3. Turbine flowmeters are generally only used to measure media with high cleanliness

The bearings of most turbine flowmeters are spherical bearings, so there is a high requirement for the cleanliness of the measured medium. If the medium contains particulate impurities, the bearing will be quickly worn, and if there are fiber impurities, it will be wrapped around the turbine blades, affecting the normal rotation of the turbine. In practical applications, an effective filter should be installed upstream of the turbine flowmeter.

The high-viscosity liquid flow meter of the self-you instrument series that is often used at present has the functions of displaying cumulative flow, instantaneous flow and zero return, and can realize on-site display and remote control. For different measuring media (acid, alkali, organic liquid, oil, food, etc.), the flowmeter can be made of different materials (cast steel, stainless steel and 316), suitable for chemical, petroleum, medicine, electric power, metallurgy and food and other industrial sector flow measurement work.

 The flowmeter with signaling function can be matched with the company's flow totalizer and other instruments, which is convenient for centralized detection, output standard signal, automatic control and data processing, etc., and can be directly connected to the computer network. 

High-viscosity liquid turbine meters working principle

The measuring part of the high-viscosity liquid flow meter is mainly composed of two intermeshing oval gears and their shells (measuring chambers). 4 times the volume, the volume flow Q passing through the oval gear meteormeter is: Q=4nυ0 In the formula: n——the rotation frequency of the oval gear (revolution/second); υ0——the volume of the half-moon part (shell).

In this way, under the condition that the half-moon volume υ0 of the oval gear flowmeter is constant, as long as the rotational speed n of the oval gear is measured, the flow rate of the measured medium can be known. The display of the flow signal of the oval gear flowmeter (that is, the rotation speed n of the oval gear) has two types: local display and remote display. Local display After the rotation of the gear is passed through a series of deceleration and speed ratio adjustment mechanisms, it is directly connected to the indicator needle on the instrument panel, and the total amount is displayed through a mechanical counter.

High viscosity liquid flow sensor features

 The remote display mainly drives the permanent magnet to rotate through the decelerated gear, so that the contacts of the spring relay are closed or disconnected synchronously at the same rotation frequency as the permanent magnet, thereby sending out electrical pulses one by one to remote to another display instrument. Main features of high viscosity liquid flow meter:

1. The flow measurement has nothing to do with the flow state of the fluid. This is because the oval gear flowmeter relies on the pressure head of the measured medium to push the oval gear to rotate for measurement.

2. The larger the viscosity of the medium, the smaller the leakage from the gear and the metering air gap. Therefore, the larger the sticky skin of the medium to be measured, the smaller the leakage error, and the better it is for the measurement.

3. High measurement accuracy, suitable for flow measurement of high-viscosity media, but not suitable for fluids containing solid particles (solid particles will cause the gear to be stuck, so that the flow rate cannot be measured). If the measured liquid medium contains gas, it will also cause measurement errors.

 Technical parameters of high viscosity liquid flow meter: 1. Intrinsically safe explosion-proof: ExiaⅡCTSdⅡBT4; 2. Connection method: flange connection: DN10~DN200; 3. Installation method: horizontal, vertical;

4. Caliber series: DN10, 15, 20, 25, 40, 50, 80, 100; 5. Pressure loss: ≤0.1MPa; 6. Accuracy class: ordinary type 0.5, high precision 0.2; 7. Medium pressure: ordinary type 1.6MPa, high pressure type 3.2MPa; 8. Viscosity range: ordinary type 0.6~200mpa. s; high viscosity 200~1000mpa. s; 9. Medium temperature: ordinary type <120℃, high pressure type <200℃; 10. Body material: cast iron, cast steel, stainless steel, etc.; high viscosity

Digital liquid flow meter installation method

1. The pipeline should be thoroughly cleaned before installation, and a filter should be installed in front of the flowmeter to prevent debris from entering the flowmeter.

 When the liquid to be tested contains gas, an air separator should be installed.

2. It should be noted that the oval gear shaft of the flowmeter must be installed in a horizontal position, that is, the dial is perpendicular to the ground plane. To adjust the flow and start, the closed valve should be installed at the inlet and outlet ends of the flowmeter respectively.

3. The direction of the arrow on the flowmeter housing should be consistent with the liquid flow direction of the installed pipeline.

4. The pipeline of continuous process and the horizontal pipeline where the flowmeter is installed should be equipped with a bypass valve for regular cleaning and maintenance.

 On a vertical pipeline, the flowmeter should be installed in the bypass pipeline to prevent debris from falling into the meter. 5. Under the condition of correct installation of the flowmeter, in order to facilitate the reading, the counter can be rotated 90 degrees according to the installation requirements.