Mud high-pressure electromagnetic flowmeter

Mud high-pressure electromagnetic flowmeter is used for measuring conductive liquid or liquid-solid two-phase media such as mud, cement slurry, high-pressure water injection, and water pump experiments under high-pressure conditions in geology, petroleum exploration, and oilfield systems. In addition to measuring the flow rate of general conductive liquids, high-pressure electromagnetic flowmeters can also measure the volumetric flow rate of liquid-solid two-phase flow, high viscosity liquid flow, and salt, strong acid, and strong alkali liquids.

1Mud high-pressure electromagnetic flowmeterInstrument Introduction:

High pressure electromagnetic flowmeter is mainly used for measuring mud in oil fields, with a maximum pressure of 40MPA or above! Most malfunctions of electromagnetic flow meters are caused by not following the instructions in the manual, and generally only minor modifications are needed to resolve them! The price of electromagnetic flowmeter is mainly related to the selection of electrodes and the material of the meter body, so the price difference is significant. Electromagnetic flow meters can only measure conductive liquids and have requirements for the temperature of the liquid, which cannot exceed 180 degrees It is generally used to measure corrosive liquids such as domestic water, sewage, mud, lime, etc. It cannot measure organic solutions and oils Due to its high measurement accuracy, easy operation, and long service life, electromagnetic flow meters are widely used Measure non corrosive liquids at temperatures below 80 degrees Celsius, typically using rubber liners For corrosive media, use F4 lining Choosing different liners and electrodes for different media is necessary to ensure the long-term stable operation of the electromagnetic flowmeter.

2、 Working principle:

According to Faraday's principle of electromagnetic induction, a pair of detection electrodes are installed on the tube wall perpendicular to the axis of the measuring tube and the magnetic field lines. When the conductive liquid moves along the axis of the measuring tube, it cuts the magnetic field lines and generates an induced potential. This induced potential is detected by the two detection electrodes, and the value is proportional to the flow rate. Its value is E=KBVD equation:

E - Induced potential;

K - coefficient related to magnetic field distribution and axial length;

B - Magnetic induction intensity;

V - average flow velocity of conductive liquid;

D - electrode spacing; (Measuring the inner diameter of the tube)

The sensor uses the induced potential E as a flow signal, which is transmitted to the converter. After amplification, transformation, filtering, and a series of digital processing, the instantaneous and cumulative flow rates are displayed on a backlit dot matrix LCD. The converter has 4-20mA output, alarm output and frequency output, and is equipped with communication interfaces such as RS-485, and supports HART and MODBUS protocols.

Mud high-pressure electromagnetic flowmeter

3、 Main components:

A high-voltage electromagnetic flowmeter consists of a sensor and a converter. The sensor is installed on the measuring pipeline, and the converter can be combined with the sensor to form an integrated electromagnetic flowmeter. The converter is installed within 30 meters or 100 meters of the sensor, and is connected by a shielded cable to form a separate electromagnetic flowmeter. The main components of an electromagnetic flowmeter sensor are: measuring tube, electrode, excitation coil, iron core, and magnetic yoke housing.

4、 Flow meter structure form:

1. Sensor:

The sensor mainly consists of a measuring conduit, measuring electrodes, excitation coils, iron cores, magnetic yokes, and a housing.

a、 Measurement catheter: composed of stainless steel catheter, lining, and connecting flange, it is a carrier for measuring the on-site working conditions of the measured liquid.

b、 Measurement electrode: a pair of electrodes installed on the inner wall of the measurement catheter, perpendicular to the axial flow direction, to generate signals for the measured liquid.

c、 Excitation coil: The upper and lower excitation coils that generate a magnetic field inside the measuring conduit.

d、 Iron core and magnetic yoke: Introduce the magnetic field generated by the excitation coil into the liquid and form a magnetic circuit.

e、 Shell: Instrument outer packaging.

2. Converter: It is an intelligent secondary meter that amplifies and processes flow signals. After being operated by a microcontroller, it can display flow and cumulative measurement, and output signals such as pulses and analog currents for measuring or controlling fluid flow.

3. Product assembly form: It is divided into two forms: integrated and split.

a、 Integrated: The sensor and converter are installed together.

b、 Split type: Sensors and converters are installed separately, forming a flow metering system through connecting cables.

c、 To meet the requirements of measuring different media, there are multiple choices for the lining and electrode materials of sensors.

5、 Application scope:

High pressure electromagnetic flowmeter is specifically used for measuring conductive liquid or liquid-solid two-phase media such as mud, cement slurry, high-pressure water injection, and water pump experiments under high-pressure conditions in geology, petroleum exploration, and oilfield systems. In addition to measuring the flow rate of general conductive liquids, high-pressure electromagnetic flowmeters can also measure the volumetric flow rate of liquid-solid two-phase flow, high viscosity liquid flow, and salt, strong acid, and strong alkali liquids.

6、 Advantages:

1. The measurement is not affected by changes in fluid density, viscosity, temperature, pressure, and conductivity.

2. The flow components of the measuring tube, no pressure loss, and low requirements for straight pipe sections.

3. The sensor can be equipped with a grounding electrode to achieve good grounding of the instrument.

4. The sensor adopts processing technology to make the instrument have good anti negative pressure ability.

5. The converter adopts a liquid crystal backlight display, which makes it easy to read under reflected sunlight or in a dark room.

6. The installation of a 90 ° rotating display screen on the pipe improves the visibility of the integrated flowmeter compared to the standard model.

7. By using infrared touch buttons to set parameters, it is possible to safely set them without opening the cover of the converter in harsh environments.

8. The converter has functions such as self diagnostic alarm output, empty load detection alarm output, flow upper and lower limit alarm output, and two pole flow value alarm output.

9. Not only can it be used for general process detection, but it is also suitable for measuring slurry, pulp, and paste liquids.

7、 Performance indicators:

1. Nominal diameter: DN25-DN250mm;

2. Nominal pressure: 6.3, 10, 16, 25, 32, 40, 70MPa;

3. Accuracy: ± 0.5% of the displayed value, optional ± 0.3% or ± 0.2% of the displayed value;

4. Lining: Polyurethane F46；

5. Electrode materials: molybdenum containing stainless steel, Hastelloy B, Hastelloy C, titanium;

6. Structural form: integrated type, split type;

7. Medium temperature: -10 to+160 ℃;

8. Environmental temperature: -25 ℃ to+60 ℃;

9. Dielectric conductivity: ≥ 5 μ s/cm;

10. Explosion proof mark: Exmb Ⅱ T4;

11. Connection method: flange type; Oil type.

8、 Installation requirements for straight pipe sections:

The flowmeter sensor has certain requirements for the upstream and downstream straight pipe sections of the installation point, otherwise it will affect the measurement accuracy.

1. If there is a tapered pipe upstream of the sensor installation point, there should be an equal diameter straight pipe section of not less than 15D upstream of the sensor and an equal diameter straight pipe section of not less than 5D downstream.

2. If there is a gradually expanding pipe upstream of the sensor installation point, there should be an equal diameter straight pipe section of not less than 18D upstream of the sensor, and an equal diameter straight pipe section of not less than 5D downstream.

3. If there is a 90 ° elbow or lower joint upstream of the sensor installation point, there should be an equal diameter straight pipe section of not less than 20D upstream of the sensor, and an equal diameter straight pipe section of not less than 5D downstream.

4. If there are two 90 ° elbows on the same plane upstream of the sensor installation point, there should be an equal diameter straight pipe section of not less than 25D upstream of the sensor and an equal diameter straight pipe section of not less than 5D downstream.

5. If there are two 90 ° elbows on different planes upstream of the sensor installation point, there should be an equal diameter straight pipe section of not less than 40D upstream of the sensor and an equal diameter straight pipe section of not less than 5D downstream.

6. The flow regulating valve or pressure regulating valve should be installed as much as possible outside 5D downstream of the sensor. If it must be installed upstream of the sensor, there should be an equal diameter straight pipe section of not less than 50D upstream and an equal diameter straight pipe section of not less than 5D downstream.

Special attention

1. If a valve is installed near the upstream of the sensor installation point, constantly opening and closing the valve will have a great impact on the service life of the sensor, and it is very easy to cause * damage to the sensor.

2. Sensors should be avoided as much as possible from being installed on very long overhead pipelines. Over time, the sagging of the sensor can easily cause sealing leakage between the sensor and the flange. If installation is necessary, pipeline fastening devices must be installed at 2D positions upstream and downstream of the sensor.

9、 Installation precautions:

1. The sensor of the flowmeter should be installed vertically, and the fluid should flow from bottom to top to meet the mixing state of solid and liquid. The reason is that solid objects (such as sediment, small stone particles, etc.) in the medium are prone to precipitation. In addition, if there are fish and weeds in the pipeline, the movement of fish in the pipeline will cause the output of the flowmeter to oscillate back and forth; The back and forth swing of weeds hanging near the electrode can also cause instability in the output of the flowmeter. Install a metal filter at the upstream inlet of the flowmeter to block fish and weeds from entering the measuring tube.

2. Improper installation and operation of the pipeline to prevent negative pressure in the flowmeter can cause negative pressure to be generated inside the sensor. When the valves upstream and downstream of the flowmeter are closed simultaneously, if the temperature of the fluid is higher than the air temperature, it will shrink after cooling, which poses a risk of forming negative pressure inside the pipe. Negative pressure causes the lining to peel off from the metal conduit, resulting in electrode leakage.

3. Add a negative pressure prevention valve near the flowmeter, open the valve to connect to atmospheric pressure to prevent negative pressure from being generated inside the sensor. When a vertical pipeline is connected downstream of an electromagnetic flowmeter, if the upstream valve of the flow sensor is used to close or adjust the flow rate, negative pressure will be formed inside the sensor measuring pipe. To prevent negative pressure, it is necessary to add back pressure or use downstream valves to regulate and close the flow rate.

4. Adequate maintenance space is often required for large-diameter flow meters to be installed in instrument wells for the convenience of pipeline installation, wiring, inspection, and maintenance. For the convenience of observation, wiring, and maintenance, instrument installation should be at a certain height from the ground for easy cleaning and installation.

10、 Correct selection instructions:

The choice of electromagnetic flowmeter should be determined based on factors such as the user's process flow, the physical and chemical properties of the measured liquid medium, installation and use environment, etc., so that the structure, diameter, flow range, lining and electrode materials, installation environment, output signal and other factors of the electromagnetic flowmeter can be determined, so that the structure, diameter, flow range, lining and electrode materials, installation environment, output signal and other parameters of the electromagnetic flowmeter meet the measurement requirements. To select a flowmeter correctly and reasonably, the following aspects can be considered based on specific usage conditions.

1. The diameter of the sensor is an important consideration factor as it affects the flow rate. In order to ensure that the medium flow rate is within the measurement range of the sensor, it is often necessary to choose an electromagnetic flowmeter that is larger or smaller than the connecting pipeline. The table provides guidelines for selecting the conventional flow rate range.

2. As an electromagnetic flowmeter, the first step is to determine its diameter and measurement range, that is, to determine the flow velocity range of the fluid inside the sensor measurement tube. The selection of the range of the flow meter is closely related to improving the reliability and accuracy of the flow meter operation. Based on the principle of not being lower than the expected maximum flow rate, the full range is selected. The normal flow rate generally does not exceed 50% of the full range, which can achieve high measurement accuracy.

11、 Main technical data:

1. Technical data of the whole machine and sensors

2. Converter technology data

3. Selection of lining

4. Selection of imported protective flanges and grounding flanges (or grounding rings)

5. Selection of electrodes

12、 Correct selection:

The selection of instruments is a very important task in instrument applications. Relevant data shows that 2/3 of instrument failures in practical applications are caused by incorrect selection or installation of instruments. Please pay special attention.

1. Collect data:

The composition of the fluid being tested;

Zui high traffic, Zui low traffic;

The highest work pressure;

Zui high temperature, Zui low temperature;

2. Range confirmation:

The flow rate of the measured medium in general industrial flow meters should be between 2-4m/s. In special cases, the minimum flow rate should not be less than 0.2m/s, and the maximum flow rate should not be greater than 8m/s. If the medium contains solid particles, the commonly used flow rate should be less than 3m/s to prevent excessive friction between the lining and the electrode; For viscous fluids, the flow velocity can be chosen to be greater than 2m/s. A higher flow velocity helps to automatically eliminate the effect of viscous substances attached to the electrode, which is beneficial for improving measurement accuracy.

Under the condition that the range Q has been determined, the size of the flowmeter diameter D can be determined based on the range of flow velocity V mentioned above, and its value can be calculated by the following formula:

Q=πD2V/4

Q: Flow rate (㎡/h) D: Inner diameter of pipeline V: Flow rate (m/h)

The electromagnetic range Q should be greater than the expected maximum flow rate value, while the normal flow rate value should be slightly greater than 50 times the full scale of the flowmeter.

3. Reference flow range:

13、 Selection Table:

14、 Ordering Notice:

1. Product: If there are model standards, please call directly to inquire about prices and learn more details!

2. If there are no product model specifications, please send the operating requirements, design drawings, and technical specifications to our company.

3. Product ordering requires parameters such as diameter (DN), nominal pressure (Mpa), temperature (℃), flow range (m3/h), medium name (such as water), connection method (clamp type, threaded type, flange type, clamping type, split type, insertion type, etc.).

4. Quotation confirmation: Our company provides a quotation list and technical standard specifications to the customer for confirmation. After both parties confirm the technical aspects, the contract will be drafted.

5. Quality requirements, quality standards, and conditions for suppliers to be responsible for quality: in accordance with relevant national quality standards.

After-sales service

1. From the date of contract signing, our company provides free maintenance and upkeep services for the products provided, and promises lifelong repair services;

2. Jiangsu Desen Instrument Co., Ltd. will regularly communicate with customers to understand the usage of the product and solve any problems that arise during their use, providing free services;

3. During the warranty period, if there is any man-made damage, our company is responsible for repairing it and collecting the repair costs incurred;

4. If there are quality problems or dissatisfaction with the product, users can choose to return or exchange it unconditionally. The company does not charge any handling fees. If there are quality problems, the company will bear the round-trip shipping costs.