Elliptical gear flowmeter

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The elliptical gear flowmeter is a field accumulative instrument, which has the advantages of simple…

I. product overview

Zw-lc series elliptical gear flowmeters are precision instruments for measuring liquid flow. It is a direct reading accumulative meter, which is a volumetric flowmeter to measure the total liquid flow through the pipeline. The flow meter can choose two counting mechanisms: mechanical display meter head and electronic display meter head. The display meter head has the functions of displaying cumulative flow, instantaneous flow and zero return, and can realize field display and remote transmission control. For different measuring media (acid, alkali, organic liquid, oil, food, etc.), the flow meter can choose different materials (cast steel, stainless steel and 316) manufacturing, suitable for chemical, petroleum, medicine, electric power, metallurgy and food and other industrial sectors of the flow measurement work.

The flow meter with signal function can be matched with the flow integrator and other instruments of the company, which is convenient for centralized detection, standard signal output, automatic control and data processing, etc., and can be directly connected to the computer network.

Ii. Working principle

The zw-lc series elliptical gear flowmeter consists of two intermeshing elliptical gears and their housings (measuring chamber). The measured mass of the elliptical gear per revolution is 4 times of the half-moon volume. The volume flow through the elliptical gear meteor meter is Q = 4n 0

Type:

N -- rotation frequency of the elliptical gear (RPM/s);

Energi0 - the volume of the lunate section (beta). .

Thus, under certain conditions of the crescent volume of the elliptical gear meter, the flow rate of the measured medium can be obtained by measuring the rotation speed n of the elliptical gear.

The display of the flow signal of the elliptical flowmeter (i.e., the rotation speed n of the elliptical gear) can be divided into local display and remote display.

Local display after the gear rotation through a series of deceleration and speed ratio adjustment mechanism, directly connected to the indicator needle on the instrument panel, and through the mechanical counter for the total display.

The remote transmission display is mainly driven by the gear after deceleration * magnet rotation, so that the contact of the spring relay with the same rotation frequency as the * magnet synchronously closed or disconnected, so as to send out an electrical pulse to another display instrument.

Iii. Application:

Zw-lc series elliptical gear flow meter is a field accumulative instrument, which has the advantages of simple structure, reliable use, high precision, small pressure loss, little influence by the change of liquid viscosity, large range and easy installation. This series of flow meters are mainly used in petroleum, chemical, grease products and other industries.

1. Zw-lc-a cast iron flow meter, widely used for measuring various oils and non-corrosive liquid media of cast iron;

2. Zw-lc-e cast steel flow meter, used for measuring high pressure and low corrosive medium;

3, zw-lc-b stainless steel flow meter is widely used in the measurement of corrosive liquid media, such as acid, alkali, salt and organic compounds.

Iv. Main features:

1. The flow measurement has nothing to do with the flow state of the fluid, because the elliptical gear flowmeter is measured by pushing the elliptical gear to rotate by the pressure head of the measured medium.

2, the greater the viscosity of the medium, from the gear and measurement clearance leakage out of the smaller the amount of leakage, so the nuclear measurement medium sticky skin, the smaller the leakage error, the more favorable to the measurement.

3, high measurement accuracy, suitable for high viscosity medium flow measurement, but not for the fluid containing solid particles (solid particles will be stuck to the gear, so that the flow can not be measured). If the measured liquid medium is mixed with gas, it will also cause measurement error.

V. technical parameters:

1, safety explosion-proof: Exia Ⅱ CTSd Ⅱ BT4;

2. Connection: flange connection :DN10 ~ DN200;

3. Installation mode: horizontal and vertical;

4. Caliber series: DN10, 15,20,25,40,50,80,100;

5. Pressure loss: 0.1mpa;

6. Accuracy grade: ordinary type 0.5, high accuracy 0.2;

7. Medium pressure: 1.6mpa for ordinary type and 3.2mpa for high-pressure type;

8. Viscosity range: normal type :0.6 ~ 200mpa.s;

High viscosity 200 ~ 1000mpa.s;

9, medium temperature: regular < 120 ℃, high pressure type < 200 ℃;

10, table material: cast iron, cast steel, stainless steel, etc.;

11. Rotating parts: aluminum alloy, stainless steel, etc.

Vi. Error calculation and adjustment

1. The basic error of the flowmeter is calculated according to the following formula from each measured value of each verified flow point :(volumetric method) E= vm-v /V 100%

E-flowmeter error (generally referred to as cumulative error) take two significant digits.

Value measured by Vm- flowmeter

V- after correction, the measured value of the standard device of the flowmeter (the actual value) is calculated by the basic error formula. When Vm > V, the basic error of the flowmeter is "+" value, indicating that the flowmeter is running faster.

When Vm < V, the basic error of the flowmeter is "-", indicating that the flowmeter is running slowly.

2, in order to make the flow meter error within the basic error limit, often need to carry out error. That is, by replacing a pair of adjusting gears (adjusting teeth) installed in the counter to change the mechanical transmission ratio, so that the flow meter is worth adjusting.

3, error adjustment can not change the flow characteristics of the flow meter, so that its characteristic curve is artificially in the new coordinate system.

Generally speaking, within the specified (or actual use) flow range, the basic error range of the zui large and zui small flow detection point is not large. 5. Within the limit of the basic error of the specified accuracy, the basic error of the flow meter can be qualified through error adjustment.

For used flowmeters, the original adjustment gear set is usually used for error verification, and then the error is adjusted according to the specific error situation.

Vii. Measurement requirements:

1. The flow measurement has nothing to do with the flow state of the fluid, because the elliptical gear flowmeter is measured by pushing the elliptical gear to rotate by the pressure head of the measured medium.

2, the greater the viscosity of the medium, from the gear and measurement clearance leakage out of the smaller the amount of leakage, so the nuclear measurement medium sticky skin, the smaller the leakage error, the more favorable to the measurement.

3, high measurement accuracy, suitable for high viscosity medium flow measurement, but not for the fluid containing solid particles (solid particles will be stuck to the gear, so that the flow can not be measured). If the measured liquid medium is mixed with gas, it will also cause measurement error