HOTLINE 0086-29-88606479
  Tel: 86-29-88606479   E-mail: sales@dechuang-auto.com

NEWS

About us

Tank seal for guided wave radar level measurement

DATE: 2015-04-22
BROWSE TIMES: 21

A microwave level gauge for measuring a level of a process material in a tank includes a ceramic seal and a microwave conductor. The ceramic seal is disposed adjacent to an opening in the tank and adapted to isolate circuitry from the process material. The microwave conductor is electrically coupled to the circuitry and extends through the hermetic seal and into the process material in the tank. The ceramic seal and an isolating adapter cooperate to isolate the microwave conductor from the process fluid and from external forces.

Level gauges are generally used in the process control industry to measure the level of material contained in a tank. As used herein, the term “tank” refers to a container, receptacle, vessel or other device for holding gases, liquids or solids. Radar level gauges are often used to measure process fluids or process solid levels in tanks, where the process materials range from benign materials to severely corrosive or abrasive compounds.

One type of level gauge for measuring a level of material in a tank is called a microwave level gauge. Microwaves are high frequency, short wavelength, electromagnetic waves. Microwaves, because of their short wavelengths, tend to travel in straight lines. This property gives rise to their application in radar, where objects are detected by the reflection of microwaves.

Generally, microwave or radar level gauges transmit an electromagnetic pulse into the materials contained within the tank, and measure the level of the process materials using the reflected pulse. As used herein, the term “microwave” refers to a high-frequency electromagnetic wave. The term “microwave pulse” refers to a microwave signal of short duration that is transmitted on a microwave antenna or conductor. The terms “microwave antenna” and “microwave conductor”, as used herein, refer to a conductive structure specifically designed to couple high-frequency electromagnetic energy (or to radiate electromagnetic energy). Typically, the microwave antenna or microwave conductor can both transmit and receive electromagnetic energy.

A microwave level gauge assembly for measuring a level of a process material in a tank with a tank atmosphere, the microwave level gauge assembly comprising:

1. a hermetic seal in contact with the tank atmosphere and fixed over a tank opening to isolate transmitter circuitry from the tank atmosphere, the hermetic seal comprising:

2. a ceramic seal body having an opening sized to receive a microwave conductor;

3. an isolating element disposed over the opening and coupled to the ceramic seal body at a coupling joint; 

4. a brazed seal disposed over the coupling joint for fixedly sealing the isolating element to the ceramic seal body; and

5. a microwave conductor extending through the opening and electrically coupled to the transmitter circuitry on one end and to the isolating element on an opposing end, the microwave conductor being sealed from the tank atmosphere by the hermetic seal.

In a conduction wave guide assembly, the antenna typically extends from a transmitter assembly into the process materials. For example, a microwave pulse travels along the antenna, and is reflected back when the pulse encounters a material with a different dielectric constant. Generally, the pulse is affected by the change in the dielectric constant at the surface of the process material within the tank. Various techniques may be used to analyze the reflected microwave pulse (including, for example, time domain reflectometry).

Since the process materials within the tank tend to be corrosive and are often stored under pressure, there is a process seal positioned between the sensor and the potentially aggressive materials within the tank. Conventionally, an O-ring or a teflon seal was used to isolate the process fluid from the transmitter housing and sensor electronics. In addition to isolating the electronics from the process fluid, such seals were typically constructed of materials selected so as not to cause microwave reflection.

While such seals typically met microwave transmission requirements, the seals were not particularly well-suited for high pressure/temperature applications.



Share to
RELATED NEWS / News More
  • Number of clicks: 1001
    2020 - 09 - 24
    Instrument knowledge|Radar level meter, how to reduce the interference in the tank on the measurement When we install the radar level meter, we will encounter many on-site storage tanks with supports, such as beams and brackets,etc . . . These supports will interfere with the signal of the radar level meter. If the above interference objects appear in the radar emission area, when the normal liquid level is below the interference objects, it will inevitably affect the normal measurement of the radar level meter, and false echo signals will appear. When encountering such situations, there are the following solutions: Method 1: Cleaning up on-site interferenceIf the interference is too large, completely occludes or most of the transmission signal of the radar level meter,...
  • Number of clicks: 191
    2020 - 09 - 22
    When selecting the type of radar level gauge, consider the influence of stirring and vacuuming, and pay attention to the power supply and output signal.1. Selection under stirringIn a tank with stirring, guided wave radar is generally not used. The force of stirring can easily bring the cable of the guided wave radar into the propeller, or bend the rod of the guided wave radar. Therefore, only high-frequency or low-frequency horn radar for non-contact measurement can be selected.If the lowest liquid level on site is above the stirring propeller, it generally has no effect on the measurement. If the minimum liquid level will be lower than the stirring propeller, it is necessary to filter out the signal reflected by the propeller by learning the function of false echo, so as to ensure that t...
  • Number of clicks: 3000
    2020 - 09 - 17
    80Ghz FMCW Radar Level meter/ continuous level sensor technical parametersCompared with 26Ghz pulse radar level meter or 6.8Ghz guided wave radar level meter, 80G radar level meter has higher frequency, shorter wavelength, smaller beam angle and more energy concentrated characteristics; coupled with the application of FMCW technology, it has the following characteristics:1.Large range, small blind area;2.The beam angle is small, the antenna size is small, and it is easy to install. Less affected by tank connection size and obstacles;3.The measurement accuracy is high, the anti-interference ability is strong, and the reliability is high. Technical parameter of 80Ghz Radar level meter  Transmit frequency:80GHz;Measuring range:0.1~30/120m;Measurement accuracy:Launch angle:3...
  • Number of clicks: 263
    2020 - 09 - 16
    Intelligent radar water level meter helps carry out flood prevention workRecently, as tropical disturbances in the southern coastal areas of my country have developed into tropical depressions, heavy rainfall has appeared in many areas of southern my country, and the flood control warning has been sounded. Since my country entered the flood season, a new round of flood control and early warning work has once again been put on the agenda. In flood warning work, the status of monitoring instruments can hardly be shaken. In order to do a good job in flood control and early warning, and prevent problems as much as possible, the intelligent radar water level meter DCRD1000A2 researched and developed by Xi'an Dechuang Electrictrical Technology Co., Ltd. not only greatly improves the measurem...
  • Number of clicks: 1001
    2020 - 09 - 10
    Why choose the radar level sensor in industrial process level instruments? The radar level sensor can measure the level that many other level instruments cannot measure, radar level sensor uses the microwave pulse measurement method and can work normally within the specified frequency range. It can be used in environments where inert gases and volatilization exist under the interference of temperature or pressure changes. The radar level sensor is a non-contact continuous measurement type process level instruments, which can be used to measure the level of liquids or solids, particle sizes and particulate materials. It corresponds to 4-20mA output, which is set by inputting the empty tank height E (=zero point), the full tank height F (=full scale) a...
Email:sales@dechuang-auto.com
Adress:
Tel:86-29 88606479
Fax: 86-29 88385903
B203, Gazelle Valley, No.69 Jinye Rd, Hi-tech zone, Xi'an, Shaanxi Province, P.R.China. 710077
Copyright ©2018 - 2019 Dechuang Electrical Technology Co., Ltd SITEMAP
Rhino Cloud Provides Enterprise Cloud Services
犀牛云提供云计算服务