What is turbine type flow meter?
Turbine type flowmeter is a typical velocity flowmeter. It has simple flow sensor construction, not bulky weight, easy maintenance, large flow rate capacity and options for high parameters: high temperature turbine type flow meter, ultra low flow turbine type flow meter, high pressure turbine type flow meter.,etc. Turbine type flow meter has good repeatability and perfect accuracy, and is widely used in various industries, for example: turbine type gas flow meter, turbine type water flow meter, turbine type air flow meter, turbine fuel flow meter
are often bought by users.
Turbine type flow meter Principle and Structure
Gas turbine type flow meter and liquid turbine type flow meters are different, not matter for liquid or gas flow rate measurement, the constructions and principles are similar.
When the fluid flows through the sensor, the impeller is forced to rotate under the action of the fluid. The rotation speed of the turbine is proportional to the average flow velocity of the fluid in the closed pipeline. The rotation of the impeller periodically changes the magnetoresistance value of the magnetoelectric converter, which is then converted into electrical pulses of the corresponding frequency by the magnetoelectric conversion device. Turbine flow transmitters counts and displays the value, and flow rate and total flow can be obtained according to the number of pulses and accumulated pulses per unit time.
A turbine type flowmeter is mainly composed of a flow sensor body, a guide body (director), an impeller, a shaft, a bearing, a signal detector and a display device. There is a guide body at the inlet and outlet of the turbine flow sensor, which guides and rectifies the fluid and supports the impeller, and is usually made of non-magnetic stainless steel or duralumin. There are many structural forms, which can resist serious disturbance of fluid flow.
Turbine, also known as impeller, is the detection element of the sensor, which is made of high magnetic permeability material. The impeller is supported by the bearing in the bracket and is coaxial with the watch body, and the number of blades depends on the diameter. The geometric shape and size of the impeller have a great influence on the performance of the turbine sensor. It should be designed according to the fluid properties, flow range, and application requirements. The dynamic balance of the impeller is very important, which directly affects the performance and service life of turbine flow meter. Signal detectors commonly used in domestic variable magnetic limit type are composed of permanent magnet steel, magnetic conductive rod (iron core), coil, etc. The permanent magnet steel is attractive to the blade and generates a reluctance torque. When a low flow turbine flow meter is in a small flow rate measurement, the reluctance torque becomes the main item in the resistance torque. For this reason, the permanent magnet steel is divided into two sizes, and the small diameter is matched with the small size to reduce the reluctance torque.
What is k factor in turbine flow meter?
Turbine type flow meter manufacture often marks K factor on the turbine flow meter .The coefficient K is obtained from the calibration of the flow standard device. It is a conversion coefficient determined according to the input (flow rate) and output (frequency pulse signal), which is convenient for practical application. However, it should be noted that the turbine type meter coefficient is conditional, and its calibration conditions are: Reference conditions, if the use deviates from this condition, the coefficient will also change.
Turbine type flowmeter Technical Specifications
Turbine flow meter size: 1/2”, 3/4 inch, 1inch, 25mm,50mm,65mm,80mm, 100mm, 4 inch, 3 inch ,6 inch turbine flow meter,8” turbine meter,10” turbine flow transmitter;
Liquid turbine flow sensor can be made into 3mm,6mm for ultra low flow measurement;
Battery operated turbine type flowmeter or 24V DC power supply
Stainless steel flow meter;
Option with display integral with turbine flow sensor to have flow rate and total flow
Process connection: thread, flanged turbine type flow meter, wafer type turbine meter;
Accuracy: Liquid 0.5% , gas turbine flow meter accuracy is 1.0-1.5 % accuracy;
Fluids can be measured by turbine type flow meter: water turbine meter, gas turbine flow meter, biogas, natural gas, air , petro ,diesel turbine meter, fuel, condensate, alcohol, milk, xylene,palm oil,etc;
Can be made into high temperature turbine type flow meter, the max liquid temperature can reach to 300°F;
Digital turbine flow meter can be with frequency , pulse and 4-20mA output,
Electronic turbine transmitter option with HART or Modbus RTU
Selection of Turbine type Flow Meters
First we should tell turbine flow meter manufacture your measured fluids, your pipeline size, your flow range, operation temperature and pressure to choose suitable type turbine flow meter.
The selection of turbine flowmeter is also based on its good repeatability and accuracy. The accuracy of liquid turbine flow meter is +0.5%R and ±1%R, and the accuracy of gas turbine flow meter is ±1%R and ±1.5%R. The accuracy is not only related to flow meters, but also closely related to the conditions of use. If the flow range is narrowed, the accuracy can be improved, if used at a fixed point, the accuracy of turbine meter can be greatly improved. In the actual selection, it should be considered from an economic point of view. For example, the custody transfer turbine flow meter for large-diameter gas pipelines is economically important, and it is cost-effective to invest money to buy high accuracy turbine type flow meter. As for the process control and internal assessment in the factory, medium flow meter accuracy is enough. For the measurement of flammable and explosive gases in hazardous areas, the explosion-proof turbine type flow meters are needed, such as turbine fuel flow meter, turbine diesel flow meter, turbine flow meter for natural gas, turbine meters for O2.,etc. and the turbine flow meter manufacturer should check the explosion-proof grade ( Exd).,For gas measurement, Silver Automation instruments produce a kind of turbine type flow meter with EVC , that is with gas or air temperature and pressure information to correct gas measurement result at standard condition, with flow unit Nm3/h.
How to choose the flow range of turbine flow meter?
The choice of the flow range of the turbine type flowmeter has a great influence on its accuracy and service life.
Generally, the velocity corresponding to the maximum flow rate during operation should not be too high. There are two types of working conditions: continuous work and intermittent work turbine flow meter. Continuous work means that the working time per day exceeds 8 hours, and intermittent work means that the working time per day is less than 8 hours. For continuous work, the maximum flow rate should be selected at the lower part of the upper limit flow rate of turbine meter, while intermittent work turbine flow meter can be selected at a higher position. For the process pipeline with low flow rate, the minimum flow rate becomes the first consideration in selecting the diameter of turbine flow sensor. Usually, the actual minimum flow rate is multiplied by 0.8 as the lower limit flow rate of turbine flow transmitter.