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 Shanghai wechat Instrument Co., Ltd
Email: 2880151138@qq.com
Telephone: +86 182-2103-2874
Address: Room 402, building B, shuangshuanglou, 650 shenzhuan Road, Songjiang District, Shanghai Online consultation

LC oval gear flowmeter

LC volumetric flowmeter is a direct reading cumulative liquid flowmeter. LCB type volumetric flowmeter is an additional transmitting mechanism on the basis of LC type flowmeter. It can be matched with our product "microcomputer flow controller". It is widely used in the measurement and automatic control of liquid flow (total) or instantaneous flow in pipelines. ...
Hotline: 182-2103-2874

Product introduction

 Picture of LC oval gear flowmeter

Oval gear flowmeter

In this paper, the liquid volume flow meter (LCB) is added to the liquid volume flow meter (LCB) of our factory. Because of its wide range, high precision, stable performance, it can measure high temperature, high viscosity liquid, simple installation, easy operation and many other advantages, it is suitable for the fluid measurement of oil exploitation, oil refining, chemical industry, commerce, oil storage and other industrial sectors.

working principle
The measurement of liquid flow is completed in the measuring room (see Figure 1). There is a pair of elliptical gears in the measuring room. Under the effect of liquid pressure difference between the inlet and outlet ends, a pair of elliptical gears continuously rotate on the rotating shaft, and the total amount of liquid flowing through the instrument can be known by measuring its revolution.
As shown in Fig. 1 (a), a pair of elliptical gears a and B separate the inlet from the outlet, and the liquid forming a crescent shaped space between gear A and the inner wall of the metering chamber is called "Yifen" (represented by shadow on the figure). Gear A has a moment of rotation and the total torque on gear B equals zero. Gear a turns gear B. Figure 1 (b) is the middle position of the two wheels. When it is moved to the position as shown in Fig. 1 (c), gear a loses the rotational torque, while gear B obtains the rotational torque, and gear B drives gear A to rotate, as shown in Fig. 1 (d). Working principle of elliptical gear flowmeter
Figure 1: working principle diagram

LC type positive displacement flowmeter is mainly composed of metering chamber, sealing mechanism and counting mechanism.
1. Measuring chamber: the instrument shell (1) (Fig. 2, Fig. 3, the same below) is made of cast iron, and its inner cavity and cover plate (4) constitute the measuring chamber. There are two stainless steel shafts (2) in the measuring chamber. A pair of elliptical gears (3) are set on the shaft, which is driven by the pressure difference at the inlet and outlet of the flowmeter. Thus, the liquid at the inlet is continuously measured by the crescent cavity and sent to the outlet
In a week, four times the volume of crescent space is accumulated. The gap between the oval gear and the wall of the measuring chamber is very small, only tens of microns, so as to reduce the leakage of the instrument.
2. Sealing mechanism: the measuring chamber of the instrument is sealed. Permanent magnetic sealing mechanism is adopted for small diameter flowmeter (see Fig. 2)
The active permanent magnet (6) and the passive permanent magnet (7) are separated by the partition plate (8). The structure has high sensitivity and reliable sealing; the large diameter flowmeter uses polytetrafluoroethylene plastic as packing seal (see Fig. 3): the compression amount of spring (7) can be changed by adjusting nut (8), so that the sealing gasket (6) can be extended to achieve the sealing purpose. The structure is simple and easy to adjust.
3. Counting structure: the counting mechanism of the instrument includes traditional gear train, transmission ratio adjusting mechanism and settlement mechanism. The total number of rotation of a pair of elliptical gears and the speed of rotation are transmitted to the pointer and word wheel of the integrating mechanism (11) after the transmission gear train (10) changes speed, the total amount of liquid passing through the pipeline and the instantaneous flow rate can be known. The transmission ratio adjusting mechanism is used to adjust and correct the instrument error (see Fig. 6).
LCB type positive displacement flowmeter is installed with electric pulse transmitter in the counting mechanism of LC type volumetric flowmeter, that is, a disc with permanent magnet is installed on the transmission shaft at the seal of LC type flowmeter, and a new type of magnetic sensitive integrated sensor is installed on the counter. The sensor has the advantages of long service life, strong anti-interference ability, wide working frequency, no spark, no fear of oil and dust, small size and convenient installation. When the magnet is close to its sensing surface and reaches the action distance, it can generate reliable detection signal without contact.
 Structure diagram of elliptical gear flowmeter
Fig. 2 rotation structure of permanent magnet for LC flowmeter
 Structure diagram 3 of elliptical gear flowmeter
Fig. 3 rotating structure of PTFE seal for LC flowmeter

Main technical data
Allowable basic error (%) ± 0.5 (± 0.2)
Maximum working pressure (MPA) 1.6
Pipe connection flange gb2555-81
Liquid viscosity (MPa. S) 0.6-250
Temperature of measured medium (℃) - 30-160
Flow range (table below)

Specification and flow range of positive displacement flowmeter
 Positive displacement flowmeter specification and flow range class 0.5
 Flow range of 0.2 level elliptical gear flowmeter
Note: when using corrosive medium, the maximum flow rate should be reduced by 1 / 3.

Installation and use
1. The flow direction of the instrument should be consistent with the flow direction shown in Fig. 4.
 Installation and use
2. The instrument shall be installed at room temperature as far as possible, and shall not be installed in the place of harmful gas and strong thermal radiation, so as to prevent damage to the counter part of the instrument.
3. The elliptical gear shaft in the instrument should be installed in horizontal position as far as possible, that is, the dial should be installed in vertical position (the graduation "0" should be on it), so as to reduce the friction between the elliptical gear and the shell and reduce the wear of parts. Due to the different installation positions, the counter (meter head) can be rotated 90 ° or 180 ° to facilitate reading (see Fig. 5).
 Installation drawing II of oval gear flowmeter
4. Before the instrument is installed, the pipeline must be thoroughly cleaned. In the whole pipeline system, if there is no strict filtering device, the filter should be installed in front of the instrument to prevent impurities from entering the meter.
5. The instrument shall be installed at the outlet end of the pump, and the flow regulating valve shall be installed at the downstream of the instrument. When using, first open the upstream stop valve, and then slowly open the downstream flow control valve or stop valve. Do not open or close suddenly.
6. When the meter is full of liquid. The measured liquid should not be mixed with gas, otherwise the mixed volume of gas and liquid is measured to make the measurement inaccurate. If there is gas in the liquid, a gas separator must be installed in front of the instrument.
7. The flow in the pipeline should not be increased or decreased sharply, and the phenomenon of pipeline vibration, hydraulic shock and rapid passive pressure should be avoided, otherwise the normal operation of the instrument will be affected.
8. When the flow rate exceeds the specified maximum flow rate, the elliptical gear wear increases with the speed, and the pressure loss increases sharply, so it should be avoided. When it is lower than the minimum flow rate, although it can still be measured, the error increases. The starting flow rate of the flowmeter is about 2% of the maximum flow rate, and the best normal flow rate is 70% - 80% of the maximum flow rate.
9. When used to measure high viscosity liquid, the liquid is generally heated to reduce the viscosity, and then flows in the pipeline. When the instrument is out of service, the liquid filled in the instrument will cool and become sticky. If it is to be used again, steam must be used to heat the liquid outside the meter body by flushing, and the liquid can be used only after the viscosity of the liquid in the instrument decreases. Otherwise, the transmission parts will be damaged if the transmission is stuck.
10. The temperature of the measured liquid should not be higher than the specified value. If it exceeds the specified value, the instrument will even be stuck. The change of liquid temperature will also cause additional error of viscosity effect. In addition, the increase of temperature also causes the volume of crescent shaped space to increase, which makes the instrument "walk slowly". When the measuring chamber is cast iron and the elliptical gear is cast aluminum, the additional error is + 0.14% / 100 ℃.
11. When leaving the factory, each instrument is calibrated with No. 7 machine oil at room temperature. The viscosity of the oil is about 10MPa. S at room temperature. If the viscosity of the liquid used by the user is quite different from this, the double-layer gear can be replaced.
12. The instrument and steam line are strictly prohibited.

Error adjustment
The basic error of the instrument within the specified minimum flow rate and maximum flow rate is not more than ± 0.5%. The calculation method of error is as follows
The cumulative indicated flow rate Q of the instrument refers to the difference between the actual flow rate of the standard vessel and the actual flow rate of the standard vessel and the percentage of the real flow rate,
error  Error adjustment formula If the instrument is fast, the error is represented by "+"; if the instrument is fast, the error is represented by "-".
1. The standard double deck gear is 38 / 35. If it is found that the instrument is running fast during the calibration, there will be a (+) error. For example, + 1.02 - + 0.3% (average error + 0.66%), at this time, the error "0" corresponding to the standard double-layer gear 38 / 35 is taken as the zero position and reduced by 0.66%. According to the error adjustment table, take the closest value of 0.62%, replace the corresponding double layer gear 41 / 38, so that the instrument can be reduced by 0.62% to + 0.4% - 0.32%, reaching the qualified range.
2. In the process of use, due to the wear and tear of gears, the accuracy of the instrument often changes, resulting in out of tolerance. As long as the error range is less than 1%, it can be adjusted to be qualified. For example, when the accuracy of the instrument is reduced to + 0.22% - 0.64% (average error - 0.21%), when replacing the double-layer gear, the number of teeth of the original double-layer gear should be seen first. If it is 38 / 35, adjust according to (1); if it is another gear, such as 41 / 38 gear, the corresponding error of the gear + 0.62% should be taken as the zero position, and the error should be increased by 0.21%, so that the error can be reduced by 0.21% to 0.41% Adjust the table and replace the double layer gear 40 / 37. The error is 0.43%, and 0.41% is the closest. After adjustment, the actual error is reduced by 0.19%, and the instrument accuracy is + 0.41% - 0.45%, reaching the acceptable range.
3. The calibration and adjustment method of 0.2 level displacement flowmeter is the same as that in item 1.2,
4. To replace the double-layer gear, first remove the shell (9 in Fig. 2 and Fig. 3), loosen the shaft sleeve (Fig. 6, the same below) and the screws (3 and 4) behind the double-layer gear, replace the adjusting gear (2), and then turn the adjusting plate (5) to make the adjustment gear mesh correctly with the gear of transmission (6) and (7), and then tighten the sleeve and screw.
 Product parts
1. Shaft sleeve 2, adjusting gear 3, 4, screw 5, adjusting plate 6, 7, rotating gear 8, 9, gasket 10, special head screw

Error adjustment table
 Error adjustment table of elliptical gear flowmeter
 Error adjustment table 2 of elliptical gear flowmeter

 Inspection and troubleshooting of elliptical gear flowmeter

Appearance and installation
Dimensions of LC / LCB series positive displacement flowmeter (cast iron, cast steel, stainless steel)
 Shape and installation of oval gear flowmeter
 Installation of oval gear flowmeter

External dimensions of LPG series filters
 Dimension parameters of LPG series filter

Technical parameters of LCB flowmeter
1. Wiring:
There are "1", "2", "3" pin serial numbers on the wiring plug, and the label "1" and "2" are connected with 12VDC (1 "is connected with positive pole,
"2" is connected with negative pole and "3" is connected with microcomputer input signal.
2. Technical parameters:
Working voltage: 12VDC; service life: > 10
7 times
Working temperature: - 10 - + 55 ℃. ; working frequency:_______ Pulse / liter
Power consumption: no more than 90mw; instrument number: ﹤ uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu.

Brief introduction of return to zero flowmeter
 Sample drawing of zero return flowmeter
Return to zero flowmeter is a set of counter which can return to zero on LC type flowmeter. When it is used, it can be turned clockwise ③ to return to zero, and press ② to rotate anticlockwise to return the pointer to zero position. The use of return to zero counter does not affect the measurement of cumulative counter.
For details, please call our technical consultant Wang Gong: 021-57632436