1. The KNKE brand turbine flowmeter imported from the United States generally consists of the following five parts. The first part is the watch body, generally made of steel or cast iron, and both ends are connected by flanges. Small-caliber instruments also use threaded interfaces. Second, the measuring parts, turbine flowmeter can also choose external lubricating oil pump to lubricate bearings, but be careful not to overdo it. The third is the counter, and important information is displayed on the counter panel. The fourth is rectifier, which is used to make the fluid flow through the turbine flowmeter in a regular state, so as to eliminate the adverse influence of disturbance on metering and improve the metering accuracy. Fifth, the magnetic coupling transmission device separates the counter part in the atmospheric environment from the measured gas and transmits the rotation of the measuring assembly to the counter.
(1) turbine
The turbine is made of magnetic stainless steel and equipped with spiral blades. The number of blades varies according to the diameter, ranging from 2 to 24. In order to make the turbine have a good response to the flow velocity, the mass is required to be as small as possible.
The general requirements of turbine blade structural parameters are: blade inclination 10- 15 (gas), 30-45 (liquid); The leaf overlap p is1-1.2; The gap between the blade and the inner shell is 0.5- 1 mm.
KNKE brand turbine flowmeter imported from the United States
(2) Bearing
The bearing of turbine flowmeter is generally a sliding cemented carbide bearing, which requires good wear resistance.
When the fluid passes through the turbine, it will produce axial thrust on the turbine, which will increase the friction torque of uranium bearings and accelerate the wear of uranium bearings. In order to eliminate the axial force, it is necessary to take hydraulic balance measures in the structure. The principle of this method is shown in Figure 3-3. Because the diameter DH at the turbine is slightly smaller than the diameter Ds at the front and rear supports, the flow section of the turbine section will become larger, and the flow velocity will decrease, so that the hydrostatic pressure will increase by P, and the static pressure of this P will offset some axial thrust.
(3) Preamplifier
The preamplifier consists of a magnetoelectric induction converter and an amplification shaping circuit.
Magnetoelectric converter generally adopts reluctance type in China, which consists of permanent magnet steel sheet and induction coil wound on it. When the fluid passes through to rotate the bite wheel, the magnetic resistance is minimum when the blades are directly below the permanent magnet steel, and maximum when the gap between the two blades is below the permanent magnet steel. The turbine rotates, constantly changing the magnetic flux of the magnetic circuit, so that the changed induced potential in the coil is sent to the amplification and shaping circuit and becomes a pulse signal.
The frequency of the output pulse is proportional to the flow through the flowmeter, and its proportional coefficient k is (3- 1).
Where: f-output pulse frequency of turbine flowmeter;
Qv-the flow through the flowmeter.
This proportional coefficient is also called the instrument coefficient of turbine flowmeter.
(4) signal reception and display
The signal receiver and display are composed of a coefficient corrector, an adder and a frequency-to-electric converter. Its function is to convert the pulse signal sent by the preamplifier into cumulative flow and instantaneous flow and display it.
The above is the answer to this question from Cohen KNKE, an American manufacturer of imported liquid turbine flowmeter. If you need to buy a liquid turbine flowmeter, please go to official website, Cohen KNKE, or ask KNKE professionals to find the most suitable product for you.