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Oval gear flow meter LZC
Oval gear flow meter, also known as displacement flowmeter, positive displacement flowmeter belonging to one of the flow meter is a high accuracy class. It uses a fluid mechanical measuring element continuously aware of the volume is divided into individual portions, According to the measuring chamber successive, repeated filling and discharge times of the volume portion of the fluid to measure the total flow volume. oval gear flow meter can choose different materials (steel, stainless steel, and 316), suitable for chemical, petroleum, pharmaceutical, Flow metering electricity, metallurgy and food industry work.
Work principle and structure
Flowmeter is installed in the metering metering box and a pair of oval gear box, and the upper and lower lid to form a sealed cavity early crescents (due to rotation of the gear, so it is not an absolute seal) as the first unit of displacement. When the measured liquid through pipes into the flow, due to the pressure difference generated at the entrances to promote a continuous rotation of the gear, keep the liquid metering moon shaped cavity in the early post-delivery to the exit, the number of revolutions per oval gear secondary displacement is four times the total amount of measured liquid product flow (principle of Figure). Flowmeter mainly by housing, counters, gears and couplings oval (sub magnetic coupling and axial coupling ) and other components.
Works oval gear flowmeters
Measuring portion LY-LC series of oval gear flow meter consists of two intermeshing oval gear and housing (measuring chamber) posed, oval gear in the measured medium pressure • p = pl-p2 role in generating The torque to rotate. When (a) position, since P1) P2, P1 and P2 in the role of co-generated torque to the wheel 1 generates a clockwise direction, the wheel 1 and a half months between the housing media to describe the product within the discharge outlet, and drive wheel 2 as the counter-clockwise direction, then one of the driving wheel, 2 wheel driven, in (b) shows an intermediate position on 1 and 2 are active wheel; and (c), as shown on the location, P1 and P2 acting together on a zero torque acting on the two combined torque to rotate counter-clockwise rotation 2, and the half-moon sucked medium volume within discharge to the outlet, then 2 as the driving wheel, a wheel is driven, and (a), the situation is just the opposite. so cyclical, round 1 and round 2 alternately with each other from one drive to another to rotate, the measured medium Unit volume in half-moon time and again from the inlet to the outlet drain. Apparently, the figure (a), (b), (c), the only represent 1/4 weeks oval gears situation, and it is discharged The measured medium as a meniscus volume so each revolution of the oval gear parallelism of the measured medium amount of meniscus volume four times through the oval gear meter meteor volumetric flow rate Q is:
Q = 4nυ0
n- oval gear rotation frequency (rev / sec);
υ0- half-moon part of the volume (shellfish).
Thus, under certain conditions meniscus volume υ0 oval gear flow meter, as long as the measured oval gear rotation speed n, you can know the flow of the measured medium.
Oval gear flow meter signal (ie, the rotational speed of oval gear n) of the display, there are two local display and remote display.
Local display will rotate through a series of gears after deceleration and adjust the speed ratio mechanism, directly connected with the indication needle on the instrument panel, and after a mechanical counter display the total.
Remote Display is mainly driven by the permanent magnet after the gear is rotated such that the spring contacts of the relay with the permanent magnet to the same rotational frequency in synchronism with closing or opening, thereby sending an electrical pulse is transmitted to the other display instruments away.
Oval gear flow meter features
Flow measurement independent of the flow state of the fluid, which is due to oval gear flow meter is to rely on the indenter measured medium oval gear driven metering of rotation.
The greater the viscosity of the medium, from gear and metering space gap smaller amount leaked leak, so sticky skin greater nuclear test medium, the smaller the leakage error, to measure more favorable.
High precision measurement of oval gear flow meter is suitable for measuring high viscosity media traffic, but does not apply to fluid containing solid particles (solid particles will gear stuck, making it impossible to measure the flow.) If the measured liquid medium is mixed with gas When, can cause measurement errors.
Oval gear flow meter installation
Oval gear flow meter should be cleaned before installation if the pipe contains solid particles in the liquid, the filter must be installed upstream pipeline; if containing exhaust gas should be installed.
Oval gear flow meter straight pipe before and after no certain requirements. It can be mounted horizontally or vertically. When installed, it should make the oval gear flow meter and the rotation axis parallel to the ground.
Use oval gear flowmeters
In accordance with the requirements of oval gear flow meter is properly installed, you can guarantee with sufficient precision, accuracy is usually cumulative value of up to 0.5, is a more accurate flow measurement instruments. However, the flow of the measured medium If you use is too small, the impact of leakage error of the instrument will be highlighted and can no longer ensure sufficient accuracy. Thus, different types and specifications of oval gear flow meter for use with a minimum allowable value, only when the actual measured flow rate is greater than the lower limit flow allowed value, the measurement accuracy can be guaranteed.
Secondly, the use of oval gear flow meter measured media to pay attention to the temperature not too high, otherwise it will not only increase the measurement error, but also the gear stuck may occur. For this reason, oval gear flow meter in the instrument specified temperature range internal use.
Oval gear flow meter after long-term use, the internal gear will be corrosion and wear, which affects the measurement accuracy. Therefore, we should always observe and regularly removed for inspection, if the conditions allow the best regular calibration.