Application and Characteristics of Radio Frequency Admittance Level Gauge

RF admittance level meterThe structure of the RF admittance level gauge product is divided into two parts: the main electrode and the compensating electrode. By applying a set of RF RF signal multi wax beams between the main electrode and the compensation electrode, it has good anti sticking and hanging characteristics, and is a new type of material/liquid level measurement product that replaces capacitive level switches.

Due to the presence of the protective electrode, the detection circuit compares the signals of the detection electrode and the protective electrode to overcome the influence of material adhesion on level measurement.

1. Strong universality: suitable for various occasions, can detect particles, fly ash, conductive and non-conductive liquids, viscous materials;

2. Anti adhesion circuit: Advanced anti adhesion circuit design can eliminate false and erroneous stepping wolf signals caused by material adhesion;

3. Power loss protection mode: low or high fault alarm. On site adjustable.

4. Easy to install and adjust

5. Not afraid of sticking or hanging materials

6. Good stability, not affected by temperature

7. Delay output adjustable

8. Optional temperature resistance up to 550 ℃

9. High and low position failure protection function

1. Power supply voltage: 220CAC ± 15% 50Hz; 24VDC ± 5%;

2. Power consumption: 4W;

3. Output signal: Relay output double pole double throw (DP/DT); 5A (resistive), 220VAC;

4. Environmental temperature: -40~70 ℃;

5. Sensitivity setting: 0.5~500pF (adjustable);

6. Delay time: adjustable from 0 to 30 seconds (on or off);

7. Power loss protection mode: Low or high fault alarm, adjustable on site.

8. Installation form: ⑴ Flange installation: According to the flange standard provided by the user;

Radio frequency admittance level gauge is a cutting-edge substitute product for international level controllers that spans the century. It has been widely used in European, American, and Japanese countries, and domestic users are also using it to replace old products. It can detect all materials without being affected by changes in parameters such as density, particle size, chemical composition, sedimentation viscosity, and conductivity. Widely used for controlling various materials such as liquids, powders, slurries, solids, etc.

Introduction to the working principle of RF admittance level gauge: The important difference between point RF admittance technology and capacitance technology is the use of three terminal technology. A wire is drawn out from the measurement signal of the circuit unit, amplified by a in-phase amplifier, and its output is connected to the shielding layer of the coaxial cable, and then connected to the shielding layer of the probe. This amplifier is a in-phase amplifier with a gain of '1'. The output signal is at the same potential, phase, and frequency as the input signal, but isolated from each other. The ground wire is the outermost shielding layer in the cable. Due to the above-mentioned relationship between the centerline and the middle shield of coaxial cables, there is no potential difference between the two, so there is no current flowing through them. That is, no current leaks out from the centerline, which is equivalent to no capacitance or zero capacitance between the two. Therefore, the temperature effect of the cable and the installation of capacitors will not have any impact. For the problem of hanging materials on the probe, a new probe structure with five concentric layers is adopted: the innermost layer is the central measuring rod, the middle is the central shielding layer, and the outermost layer is the grounding installation thread, which is isolated separately by an insulation layer.

The situation is the same as with coaxial cables. There is no potential difference between the measuring rod at the center of the mold bench and the shielding layer. Even if the impedance of the hanging material on the sensing element is small, no current will flow through. Electronic instruments only measure the current from the center of the probe to the opposite tank wall, because the central element can hinder the current from flowing upward along the probe to the container wall. Therefore, the ground current can only pass through the end of the probe and the measured material to the opposite container. That is, Ua=Ub lab=(Ua Ub)/R=0. Due to the potential difference between the shielding layer and the container wall, although there is current flowing between the two, it is not measured and does not affect the measurement results. This protects the measuring end from the influence of hanging materials. Only when the level of the substance in the container does rise and come into contact with the central measuring rod, a measured current is formed between the central measuring rod and the ground through the measured material.

Conductive and insulating liquids: Chemical, oilfield, water and sewage treatment

Conductive and insulating pastes: Paper making, pharmaceuticals, water and wastewater treatment

Powder: ash, powder, power plant, metallurgy, cement

Particles: coal, grains, power plants, metallurgy, grains

Interface: Two different types of liquid swing bodies for oil fields and chemical industries

Technical parameter measurement accuracy Repeatability Conductive medium<2mm Non conductive medium<50mm

Temperature range: medium temperature -200 ℃∽+800 ℃ (select the corresponding sensor probe)

Environmental temperature -40 ℃∽+60 ℃ Storage temperature -40 ℃∽+60 ℃

Response time 0.3s or 0-20s continuously adjustable

Sensitivity better than 0.3PF

Temperature affects every 10 ℃± 0.05PF

Signal output DPDT relay output, two sets of normally open and normally closed contacts plow the ground

Contact capacity: AC200V5A DC24V5A

Power supply 220V AC or 24V DC

Power consumption 4W

Protection level IP66

Process connection external thread G3/4 ", G1"

Flange type GB-9123-2000 DN50 PN0.6MPa

The sensor electrode extension rod has a maximum length of 3m and a minimum length of 0.4m, made of stainless steel 304+PTFE plastic, ceramic, or other specified materials.

The cable type has a maximum length of 35m and a minimum length of 0.5m, and is made of stainless steel 304+PTFE plastic or other specified materials.

The standard length of the protective electrode is 100mm or 300mm, and the material is stainless steel 304+PTFE plastic, ceramic, or other specified requirements.

Type A plastic PBTP shell

B-type die cast aluminum, epoxy resin spraying

Cable entry hole M20x1.5 with plastic cable sealing sleeve

Explosion proof standard ExdIICT5