Radio frequency admittance level meter

Radio frequency admittance level meter is widely used for continuous measurement of liquid particles and bulk material silo levels in various industries. It is suitable for measurement in environments with high temperature, high pressure, strong corrosion, strong adhesion, strong impact, strong wear and dust, and has a cost-effectiveness that other types of level meters cannot match. The product is used in industrial and mining sites and is suitable for most applications. The instrument consists of a circuit unit, an explosion-proof housing and a rod or cable sensing element. The sensor is available in a variety of models, and the instrument can be installed integrally or separately.
Measurement principle of radio frequency admittance level meter
Radio frequency admittance is a new material level control technology developed from capacitive type that is more reliable, more accurate and has wider applicability. Bit technology upgrade. The so-called radio frequency admittance, the meaning of admittance is the reciprocal of impedance in electricity. It is composed of resistive components, capacitive components and inductive components. Radio frequency is the high-frequency radio wave spectrum, so radio frequency admittance can be understood as using high-frequency radio waves. Measure admittance. When the instrument is working, the sensor of the instrument forms an admittance value with the irrigation wall and the measured medium. When the material level changes, the admittance value changes accordingly. The circuit unit converts the measured admittance value into a material level signal output to realize material level measurement.
For continuous measurement, the difference between radio frequency admittance technology and traditional capacitance technology, in addition to the above mentioned, also adds two very important circuits. This is based on a very important discovery and improvement in the practice of conductive hanging materials. made. The above-mentioned technology also solves the problem of connecting cables at this time, and also solves the problem of hanging materials on the roots of vertically installed sensors. The two circuits added to the lock are the oscillator buffer and the AC conversion chopper driver.
For a container with a highly conductive measured medium, since the measured medium is conductive, the ground point can be considered to be on the surface of the probe's insulating layer, which only appears as a pure capacitance to the transmitter. As the container is discharged, hanging material is produced on the probe rod, and the hanging material has impedance. In this way, the former pure capacitance has now become a complex impedance composed of capacitance and resistance, which causes two problems.
The first problem is that the liquid level itself is equivalent to a capacitor for the probe. It does not consume energy from the transmitter. Pure capacitance does not consume energy. However, if the equivalent circuit of the mounting material to the probe contains a resistance, the impedance of the mounting material will consume energy, thus pulling down the oscillator voltage, causing the bridge output to change, resulting in measurement errors. We added a buffer amplifier between the oscillator and the bridge to replenish the consumed energy without reducing the oscillation voltage applied to the probe.
The second problem is that for the conductive measured medium, the grounding point on the surface of the probe's insulating layer covers the entire measured medium and hanging material area, so that the effective measurement capacitance extends to the top of the hanging material. This will produce a hanging error, and the stronger the conductivity, the greater the error. But no measured medium is completely conductive. From an electrical point of view, the hanging material layer is equivalent to a resistor, and the part of the sensing element covered by the hanging material is equivalent to a transmission line composed of countless infinitesimal capacitance and resistance elements. According to mathematical theory, if the hanger is long enough, the impedance of the capacitive and resistive parts of the hanger is equal. Therefore, based on the study of the error caused by the impedance of the hanging material, an AC driver circuit was added. This circuit, together with an AC converter or a synchronous detector, can measure capacitance and resistance respectively. Since the impedance and capacitive reactance of the hanging material are equal, the measured total capacitance is equivalent to + hanging material, and then subtracting the resistance equal to the hanging material, the true value can be actually measured, thereby eliminating the influence of the hanging material.
That is, measurement + hanging material
Measurement and hanging material
Measurement
These, multi-parameter measurement, are the necessary basis, and the AC phase detection sampler is the means to achieve it. Due to the use of the above three technologies, radio frequency admittance technology has shown extraordinary vitality in field applications.
Product Features of Radio Frequency Admittance Level Meter
The calibration is simple and can be automatically completed at one time using any two points of warehouse height.
It has strong versatility and can measure liquid level and material level. It can meet the measurement requirements of different temperature and pressure media, and can be used in harsh situations such as corrosion and impact.
The unique circuit design and sensor structure of the anti-sticking material make the measurement unaffected by the sensor hanging material, eliminating the need for regular cleaning and avoiding mismeasurements.
There are no moving parts in the maintenance-free measurement process, there is no problem of damage to mechanical parts, and no maintenance is required.
Anti-interference contact measurement, strong anti-interference ability, can overcome the influence of steam foam and stirring on measurement.
Wide applications: Liquid-solid interface mixture materials can be used.
No drift There will be no drift due to changes in temperature or density of the medium.
Accurate and reliable measurement quantity is diverse, making the measurement more accurate. Zeliang is not affected by environmental changes, has high stability and long service life.
Liquid crystal display adopts liquid crystal display, and the display content is rich and comprehensive.
Typical applications of radio frequency admittance level meter
Conductive insulating liquid chemical oil field water and sewage treatment
Conductive insulating slurry papermaking pharmaceutical water and sewage treatment
Powder ash power plant metallurgical cement
br/> Granular coal grain power plant metallurgical grain
Two kinds of liquid oil field chemicals with different interfaces
Radio frequency admittance level meter performance indicators
Power supply
Spark protection built-in spark protection circuit for the sensor
br/> Output
Electrical interface
Output method level method or distance method
Cable Special connecting cable standard between separate electronic unit and sensor, longest
Accuracy
Ambient temperature ℃～℃
Process connection thread installation standard
Medium temperature ℃～℃
Flange installation optional
Maximum load
Shell protection
Load affects the maximum load
Explosion-proof II
Response timetable is adjustable
Maximum range, maximum distance, different sensors have different maximum ranges