In order to adapt to the production of the flow measurement of different media and different conditions of work requirements, have a variety of different types of volumetric flowmeter. Which are the more common type gear, and the scraper-type rotary-piston, three Type, respectively, are presented below.

1Gear-volume flowmeter

This flowmeter contents of the shell has two rotors, directly or indirectly, of mutual engagement, in flowmeter between the imports and exports under the pressure generated rotation. Gear through the rotation, continue to be in full gear and Shell Between the "measurement space" in the fluid discharged. Rotation by measuring the number of gears, available through the flowmeter fluid volume.

Figure 2-1 in the show is a volume flow meter oval gear type (also known as Ao Baer volume flow meter) diagram

Figure 2-1 oval gear flow meter work diagram

Visible from the map, the two oval gear flow meter from mutual engagement to work, the course of their work summarized as follows: Figure in P1 that imports of fluid pressure flowmeter; said exports fluid pressure, pressure P1 is greater than P2. In Figure 2-1 (a), below the rotor Although the fluid pressure, but do not have a rotation torque, and the top gear in the two cases under a differential rotation and torque rotation. since the two gears meshing each other, the respective to O1, O2 As the axis by rotating the direction of the arrow, and will gear O1 Ban Yuexing space measurement of fluid row to export. In Figure 2-1 (a) state, to take the initiative on the gear wheels, gear for the next round follower. In Figure 2-1 (b) position, the two gears are in the fluid under a differential rotation torque, and torque under the direction of rotation along the arrow, changes to the map 2-1 (c) shows the location. gear position and at this time Figure 2-1 (a) On the contrary, gear for the next round of the initiative, driven on the gear for the round. Gear in the import and export under the differential fluid under rotation, it will once again between the shell and a half months "Measurement of space" The fluid from. So continuous movement, an oval gear to every week, from four in the "measurement space," fluid volume. Therefore, as long as the gear to read out the number, you can calculate from the volume of liquid. Refer to Figure 2-2 , A calculation from the total volume of fluid

V4nv

2 nR 2 ab 24

In-n - the rotation frequency of gear

abThe long oval gear Banxiu, short-uranium

---- The thickness of oval gear

Another gear-volume flowmeter is Roots volume flow meter, also called Roots-type volume flow meter. Flowmeter this principle and work process and basically the same type oval gear, is also relying on imports and exports of fluid pressure A poor campaign, rotating each week from four "measurement space," the volume of fluid. The difference is not in the lumbar round teeth, they are not engaging each other directly rotation, but through the shell, packed in the transmission gear transmission group .

These two types of rotor volume flow meter, can be used for all kinds of liquid flow measurement, particularly for the oil flow of accurate measurement. In high-pressure, the flow of gas flow measurement, such flowmeters also have application. As elliptical Gear flowmeter directly depend on volume measurement round of mating, the cleanliness of the media higher, solid particles are not permitted through the flowmeter impurities.

2Scraper-volume flowmeter

Scraper flowmeter is also a common volume flowmeter, in which the flow meter is equipped with two pairs of the rotor can slip inside and outside the radial scraper, the rotor in the flowmeter import and export under the differential rotation, each Moment of the week from four "measurement space," the fluid volume. Flowmeter with the former the same, as long as the number of detected rotation, we can calculate from the volume of fluid.

The more common cam-scraper flowmeter structure shown in Figure 2-4. Shell plans in the inner cavity is a circular air cylinder, the rotor is a hollow cylindrical object, a certain width of the radial, in the radial 90 for each of the four slot open position, sliding scraper can be free bed. Scraper from two four-link link, mutual vertical, in-space. Scraper at the end of each equipped with a small ball, 40 Have a ball in a fixed cam rolling on the scraper, when SIN shrink. When the two neighboring scraper are extended to the housing wall, they form - the standard volume measurement space. Scraper in the measurement section campaign , Not only with the rotor rotary sliding to ensure that its standard volume constant. When the left measurement section, the scraper shrink into the bed, fluid discharged from exports. At the same time, after a scraper and its adjacent scraper formed another section 2 "measurement space," the same action. Rotor movement a week, from four in the "measurement space," the volume of fluid.

Volume in the scraper-type flowmeter, the so-called rotary valve scraper flowmeter, it works the Cam similar, but different structures, not described in detail here.

3Rotary piston volume flowmeter

Rotary piston (also known as the swing piston) volume flow meter and the structure of that principle as shown in Figure 2-5.

Figure rotation in Detroit and outside the ring fixed between 3 and 4, Detroit 6 rely on the guide roll axis rolling 5, a middle partition will measure space divided into two parts, Detroit 2 on the gaps and partition a bite, when the Pistons according to the direction of the arrow, with the partition movement into a linear motion. Pistons in the import and export of fluid under pressure from the poor, always with the outside wall in close contact with the drum rotation, alternating with the Pistons continue to be both inside and outside the fluid from the cylinder, Detroit rotation by calculating the number of available flow of the fluid.

Rotary piston flowmeter volume of flow capacity greater advantages. It is inadequate in the process there will be some leakage, so accuracy of the low.