In this paper, an oval gear flow meter is taken as an example to discuss the process and method of automatic adjustment of the flowmeter and the existing communication and other aspects of technical transformation, and to improve the work efficiency, so as to better meet the current needs in the gas station flowmeter calibration . This method can improve the accuracy and efficiency of calibration and provide timely and accurate refueling services. 1 Operating principle of oval gear flow meter The measurement part of the oval gear flow meter is mainly composed of two intermeshing elliptic gears and their outer casing (metering chamber), as shown in FIG. 1 . Figure 1 Composition of the measurement section The elliptic gear produces a working moment to rotate due to the pressure difference Δp=p1-p2 of the measured medium. In the position shown in FIG. 1a, due to P1>P2, under the action of P1 and P2, the resultant torque causes the wheel 1 to rotate in a clockwise direction, and the medium in the half-moon container between the wheel 1 and the housing is arranged. Go to the exit and drive the wheel 2 to rotate counterclockwise. At this time, 1 is the driving wheel and 2 is the driven wheel. Figure 1b shows the middle position. Both Wheel 1 and Wheel 2 are driving wheels. In the position shown in Fig. 1c, the resultant moment of P1 and P2 acting on the wheel 1 is zero, and the resultant torque acting on the wheel 2 causes the two wheels to rotate counterclockwise and the medium in the half-moon container has been sucked. From the row to the exit, wheel 2 is the drive wheel and wheel 1 is the driven wheel, which is just the opposite of what is shown in Figure 1a. In this reciprocal cycle, the wheel 1 and the wheel 2 alternately rotate one by one, and the medium to be measured is discharged from the inlet to the outlet once in a half-moon volume. Obviously, Fig. 1 merely shows that the elliptical gear rotates for a quarter of a turn, and the medium to be measured is a half-moon volume; therefore, the amount of measured medium discharged per one revolution of the elliptical gear is a half-moon shape. At 4 times the volume, the volumetric flow Q of the elliptic gear meteormeter is: Q=4nÏ…0 In the formula, n is the rotation frequency of the oval gear; Ï… 0 is the volume of the half moon shape part. In this way, the flow rate of the measured medium can be known by measuring the rotation speed n of the elliptic gear under the condition that the half-moon volume æ¤åœ†0 of the oval gear flow meter is constant. Oval gear flow signal (ie, the rotation speed n of the oval gear) has two kinds of local display and remote display. The local display shows that the rotation of the gear is through a series of deceleration and adjustment of the speed ratio mechanism, and is directly connected with the indicator pin on the instrument panel, and the mechanical counter is used to display the total amount, as shown in FIG. 2 ; the remote transmission display mainly The decelerated gear rotates the permanent magnet, so that the contact of the spring relay is synchronously closed or disconnected at the same rotation frequency as the permanent magnet, so that an electric pulse is transmitted far away to another display instrument. Figure 2 shows the local display 2 flow meter system improvement 2.1 MCU control system principle The hardware of the SCM control system is mainly composed of a key section, a single-chip microcomputer section, a communication section, a pulse receiving section (counting section), and a control valve 5 section, as shown in FIG. The pulse signal is counted by the counter portion of the single-chip microcomputer, the host computer and the one-chip computer communicate through RS485, the valve control is realized through the electromagnetic relay. Figure 3 Schematic diagram of the hardware structure of the flowmeter MCU control system FRP/GRP Cooling Tower,Fiberglass Cooling Tower,FRP Water Cooler Cooling Tower,FRP Fiberglass Cooling Tower Hebei aoliande Chemical Equipment Co., Ltd , https://www.frpgrppipe.com
