Vortex flowmeter is one of the most commonly used field instruments in industry. Its sensor accepts 12VDC from the secondary instrument and uses a piezoelectric crystal element to detect the vortex separation frequency. In use, the probe body installed inside the cylinder feels the pressure pulse generated by the vortex on both sides of the cylinder, and the piezoelectric crystal element buried inside the probe body feels the effect of this strain force to generate the alternating charge. The sensor processes a pulse signal with a certain amplitude to the secondary instrument. This pulse signal is proportional to the flow through the pipe. This proportional relationship is determined by the K factor of the sensor. The K factor is generally calibrated by the manufacturer. The K factor indicates the number of pulses emitted by each flow unit sensor in the pipeline. The secondary instrument is a flow display instrument mainly composed of an MCS51 series single-chip 8031. After receiving this pulse signal, on the one hand, the instantaneous current is displayed by the pointer type ammeter. On the other hand, the accumulated flow or accumulated time is displayed by 8 digits on the other hand. It can output 4 to 20 mA or 0 to 10 mA signals to regulators or recorders. The secondary table is parameterized based on the K-factor and flow rate of the sensor. The main problem 1 indicates long-term inaccuracy; 2 always has no indication; 3 indicates large-scale fluctuations and cannot be read; 4 indicates no return to zero; 5 indicates no indication of small flow; 8 indicates large flow indication, and small flow indicates incorrect indication; 7 flows When the change indicates that the change can not keep up; 8 instrument K factor can not be determined, multiple data are inconsistent. Analysis and Solution of Major Problems The analysis and solution of these problems took nearly half a year. Due to the complexity of the problems, there were varying degrees of problems in the installation, parameter setting, routine maintenance, and operating environment. Many problems were involved in each other, and some problems were solved. Waiting for a certain timing of the process, it has brought great difficulties to solve the problem. Some problems are caused by a combination of different reasons. Some of them are related to different issues. The main reasons for these problems are summed up in the following aspects: (1) Problems with type selection. Some vortex sensors in the caliber selection or after the selection of the design due to changes in process conditions, making a large selection - a specification, the actual selection should choose the smallest possible diameter, in order to improve the measurement accuracy, mainly in this regard Questions 1, 3, and 6 are relevant. For example, a vortex street line is designed for use on several equipment. Because some of the equipment in the process is not used sometimes, the current actual use flow rate is reduced, and the actual use causes the original design selection aperture to be too large, which is equivalent to increasing the measurable flow rate. The lower limit indicates that the flow rate can not be guaranteed when the flow rate in the process pipeline is small, and it can be used when the flow rate is large, because it is very difficult to re-engineer (sometimes, the change of process conditions is only temporary). The re-tuning of the parameters can be combined to improve the indication accuracy. (2) Installation problems. The main reason is that the length of the straight pipe section in front of the sensor is not enough, affecting the measurement accuracy. The reasons for this are mainly related to Problem 1. For example: Two-pass FIC203 sensor in front of the straight pipe segment is obviously insufficient, because FIC203 is not used for measurement, just for control, so the current accuracy can be used (equivalent to degraded use). (3) The reason of parameter setting direction. Due to a wrong parameter, the instrument indicates an error. The parameter error causes the secondary instrument full-scale frequency to be calculated incorrectly. The reasons for this are mainly related to problems 1 and 3. Full-scale frequency is similar to the indicator that the long-term inaccurate, the full-scale frequency of the actual full-scale calculation of the full-scale frequency indicates that a wide range of fluctuations, can not read, and the inconsistency of the parameters on the data has affected the final determination of the parameters, and finally passed The recalibration combined with each other determines the parameters and solves this problem. (4) Secondary instrument failure. This part of the more failures, including: an instrument board circuit is broken, the range settings have a bit of individual display is bad, K-factor is set to display a bad individual bits, making it impossible to determine the range setting and K-factor setting, which Some of the reasons are mainly related to questions 1 and 2. By fixing the corresponding fault, the problem is solved. (5) Four-way line connection problem. The circuit is well connected on the surface of some loops. Carefully check that some of the connectors have actually been loosened and the loop is interrupted. Although some connectors are tightly connected, the fastening screws are fastened to the wire sheath due to the problem of the secondary wires. Interruption, this part of the reason is mainly related to question 2. Solved the corresponding line problem, the existing problems are also resolved. (6) The connection problem between the secondary instrument and the subsequent instrument. Due to problems with subsequent instruments or due to subsequent instrument overhaul, the mA output circuit of the secondary instrument is interrupted. For this type of secondary instrument, this part is mainly related to Problem 2. Especially for the follow-up recorder, in the case of long-term damage to the recorder can not be repaired, we must pay attention to the output of the secondary short-circuit meter. (7) The loop has no indication due to the failure of the secondary meter flat cable. Due to the long-term operation, coupled with the impact of dust, resulting flat cable failure, by cleaning or replacing the flat shaft wire, the problem can be solved. (8) For problem 7 is mainly due to the fact that the secondary meter shows the head coil fixing screws loose, causing the head to sink, the pointer and the case friction, action is not working, by adjusting the meter head and re-fixed, the problem is resolved accordingly. (9) Use of environmental issues. Especially in the sensor part installed in the well, due to the high humidity in the environment, the circuit board is damped. This is partly due to problems 2 and 2. Through corresponding technical reform measures, the part of the sensor with a large environmental humidity was re-disposed of the probe part and the conversion part, and a separate sensor was used. Therefore, the working environment was good, and this part of the instrument was working well the other day. (10) Due to poor on-site adjustment, or due to changes in the actual situation after adjustment. Due to live vibration and noise balance adjustment and sensitivity adjustment is not good. Or, due to the re-alteration of the situation after the adjustment for a period of time after the adjustment, the indication problem is caused. This part of the reason is mainly related to questions 4 and 5. Use the oscilloscope, combined with the operation of the process, readjust. (11) The reason why question 8 is proposed separately is that this problem has affected the analysis and solution of the problem for a long time. Because the eastern chemical plant does not have the K factor calibration condition, the K factor can only be based on the information provided by the manufacturer, due to the manufacturer itself. Some of the changes caused by the K-coefficient on the several data provided did not affect the solution to the problem. By re-calibrating the conditions, or by repeatedly modifying and contrasting, the unified instrument parameters are finally determined. Through careful analysis of a period of time, the problems existing in the vortex street can be basically solved. At present, this part of the instrument runs well and basically meets the needs of the factory's process production. to sum up (1) Because the determination of K-factor is very heavy in the entire process of vortex street, the accuracy of K-factor directly affects the accuracy of the loop, and the wear of instrument replacement parts and process piping may affect the K-factor. . The Eastern Chemical Plant also lacks the means and capability of calibration. It can only send calibrations and is affected by the operation of the process. To remove the vortex from the pipeline, it takes 5 to 6 days to send the calibration time, and the process is difficult to satisfy, so that it cannot be determined. K factor. This year, through the transformation of flow meters, although smaller caliber calibration conditions have been established for vortex street, it is still not possible to use vortex street with larger diameter. In the future, attention should be paid to the use of vortex street calibration methods, standard frequency, and portable ultrasound. The flow meter measures the instantaneous flow rate in the pipe and the pulse output frequency of the sensor and calculates the K factor on site. (2) The probes of vortex flowmeters should be regularly cleaned. During the inspection, it was found that individual probe holes have been blocked by dirt and even wrapped in plastic sheets, affecting normal measurements. (3) Regularly check the grounding and shielding to eliminate outside interference. Sometimes the indication is due to interference. (4) Install the wet probe. Should be dried once a day, or for moisture treatment. Because the probe itself is not damp-proofed at the end, the dampness affects the operation. (5) The management of data data of the instrument should be given sufficient attention to facilitate future work. Jiangsu Jinyuan Instrument Co., Ltd. as a Jiangsu brand quality flow meter manufacturer, Main Products: sewage flow meter, electromagnetic flow meter, steam flow meter, gasoline flow meter, turbine flow meter, ultrasonic flow meter, orifice flow meter, steam flow Meters, etc., for the vast number of consumers to provide sincere and honest quality services. Welcome new and old customers advice and procurement, we have to serve you! Our factory is located in the Three Lakes, surrounded by sunrise, gold bucket, by the beautiful Township of Zhou Enlai personally named the township: Jinhu, if you need to come to our factory inspection and observation, you are also welcome to enjoy our small town of Sanhe scenery, Shili River swing, Morning Drum Zhong Ming, enjoy our small town's nostalgic fishing fun, lake food, Sen bath fragrant! Alnico (AlNiCo) is the first developed a permanent magnet is made of aluminum, nickel, cobalt, iron and other trace metals composition of an alloy.According to different production process is divided into sintered Alnico (Sintered AlNiCo), and cast aluminum nickel and cobalt (Cast AlNiCo).Product shape of the round and square. Sintered products limited to the small size, their production out of rough tolerance is better than the rough cast product can be better workability. Alnico Magnet,Alnico Magnets,Alnico V Magnets,Alnico Rod Magnets,Alnico 3,Alnico 5 Jinyu Magnet (Ningbo) Co., Ltd. , https://www.magnetbonwin.com
Alnico alloys can be magnetised to produce strong magnetic fields and have a high coercivity (resistance to demagnetization), thus making strong permanent magnets. Of the more commonly available magnets, only rare-earth magnets such as neodymium and samarium-cobalt are stronger. Alnico magnets produce magnetic field strength at their poles as high as 1500 gausses (0.15 teslas), or about 3000 times the strength of Earth's magnetic field. Some brands of alnico are isotropic and can be efficiently magnetized in any direction. Other types, such as alnico 5 and alnico 8, are anisotropic, with each having a preferred direction of magnetization, or orientation. Anisotropic alloys generally have greater magnetic capacity in a preferred orientation than isotropic types. Alnico's remanence (Br) may exceed 12,000 G (1.2 T), its coercivity (Hc) can be up to 1000 oersteds (80 kA/m), its energy product ((BH)max) can be up to 5.5 MG·Oe (44 T·A/m). This means that alnico can produce a strong magnetic flux in closed magnetic circuits, but has relatively small resistance against demagnetization. The field strength at the poles of any permanent magnet depends very much on the shape and is usually well below the remanence strength of the material.
Alnico alloys have some of the highest Curie temperatures of any magnetic material, around 800 °C (1,470 °F), although the maximal working temperature is normally limited to around 538 °C (1,000 °F).[4] They are the only magnets that have useful magnetism even when heated red-hot.[5] This property, as well as its brittleness and high melting point, is the result of the strong tendency toward order due to intermetallic bonding between aluminium and other constituents. They are also one of the most stable magnets if they are handled properly. Alnico magnets are electrically conductive, unlike ceramic magnets.
Alnico magnets are widely used in industrial and consumer applications where strong permanent magnets are needed; examples are electric motors, electric guitar pickups, microphones, sensors, loudspeakers, magnetron tubes, and cow magnets. In many applications they are being superseded by rare-earth magnets, whose stronger fields (Br) and larger energy products (BHmax) allow smaller-size magnets to be used for a given application.