Electromagnetic flowmeter type matters needing attention, the accurate measurement of the total flow of the electromagnetic flowmeter is more complicated, so as to exceed the objective of accurate and accurate measurement, not only to understand the basic principle and characteristics of the flowmeter, but also to pay attention to all related matters of the detection system.In terms of the application, attention must be paid to the motor selection, installation, application, maintenance and other stages to ensure the proper and effective application of metrological verification instruments.
1. Natural environment standards
Electromagnetic flowmeter installation is divided into two types: integral and separated.
(1) under the standard of good spot and natural environment, the controller and converter are generally integrated into one.
(2) the separated electromagnetic flowmeter, namely, the controller and the converter are separated and installed at different addresses. The separated flowmeter is generally adopted when the following conditions occur:(2) pipeline vibration is very big place;(3) the controller of the aluminum case is more serious erosion site;(4) the environment on the spot humidity is very high or there are corrosive vapors;The flowmeter is installed in a high position or in an inconvenient place.
2. Explosion-proof type and waterproof grade
According to the natural environment, choose the safe, flameproof or universal electromagnetic flowmeter, and consider a certain waterproof grade, according to the standard to carry out the installation, improve the safety factor of the instrument.
3. Electrode raw materials
Conductive medium in the electromagnetic flowmeter tube according to the time, in addition to the effect of the electromagnetic field under the magnetic induction potential difference, the effect of the electrode is that the resulting electromotive force out, and then become larger, output specification data signal.Electrode immediately contact with the medium, therefore, should be based on the physical properties of the medium, choose the appropriate electrode, to prevent erosion.Common electrode materials are tantalum, titanium, 316L, HC, platinum-iridium aluminum alloy, cobalt alloy and so on.
4. Grounding ring or connecting ring
The output data signal of the electromagnetic flowmeter is relatively small, generally only 2.58mv. When the total flow is small, the data signal will be as low as a few microvolts, and any external influence will jeopardize the precision of accurate measurement.Therefore, instrument housing, accurate measurement tube, media, instrument shielding cable to do a good job of equipotential connection, and carry out reliable, independent grounding.The part of a metal material that is connected to a medium is called an earth ring or a liquid ring.The selection of the raw materials of the earthing ring generally takes into account the rationality and corrosion resistance. For the electromagnetic flowmeter on the pipe line of large specifications of metal materials, in order to save cost, the earthing ring can be removed and the flange of the flowmeter can be connected with the pipeline and then grounded;If the electromagnetic flowmeter is used in the diameter of the pipeline or in the non-metallic material pipeline, be sure to set the earthing ring.
5. Uchimura raw materials
The key function of the lining is insulation to prevent short circuit fault of the electrode and to maintain the accurate measurement tube from medium erosion.Common lining raw materials include: polyurethane vulcanized rubber, PFA, pure natural soft vulcanized rubber, EPDM vulcanized rubber, the selection should be based on the temperature of the medium, corrosion, whether with solid particles, wear resistance, etc.
Porcelain city Shanghai instruments co., LTD., founded by former Siemens MrStone senior engineers, specializing in high quality, high precision, wide range of flow meter of the research and development and production work, independent research and development of our products enjoys a high reputation in the industry, small flowmeter development make up the blank of domestic small flow meter, the quality of the product can completely replace the Max, KRACHT (clark), OVAL and other international brands.