Abstract:Vortex Flowmeter from the scene there had been used in some of the issues that should be in use and maintenance of the attention of

Key words: vortex flowmeter installation, use of maintenance

Basic profiles

222A and two water treatment stations in Beijing Dongfang Chemical Plant on public works system plays a very important role, 222 A main water station is to start boiler to provide water desalination, as ethylene, ethylene oxide / ethylene drunk to provide water purification , To provide softening on the Alkali Water from the second through the main purpose of ethylene, ethylene oxide / ethylene drunk, started boiler, water stations provide cooling water.

In these two devices, I used the plant a total of 22 Taiwan-LUGB vortex flow sensors and matching the second-FD910 instrument.

Vortex flow meter sensor to accept the second 12 VDC power supply, the use of piezoelectric crystal device detection vortex separation frequency. Cylinder installed in the internal probe of feelings on both sides of the rear cylinder in the vortex of the pressure pulse, planted in the probe of internal Piezoelectric crystal components to feel the strain of alternating the role of a charge, the sensor output must deal with the pulse rate to secondary instruments. This pulse and flow through the pipeline in proportion to flow, the ratio between the K-factor from the sensor decision, K factor from manufacturers in general calibration, K factor that flow through a pipeline flow per unit issued by the pulse sensor number.

Second is the instrument by the MCS51 MCU 8031 as the main flow meter showed that, in this pulse received, on the one hand Instantaneous show Ammeters pointer from the traffic, on the one hand by the eight digital display cumulative flows or aggregate time, On the other hand, output 4 ~ 20 mA or 0 ~ 10 mA signal to the regulator or the use of monitoring devices. Second table based on sensors and the K-factor flow range to set parameters.

The main problem

From 22 sets of vortex flowmeter used so far, there have been many problems. Mainly: no long-term direction; has no instructions; instructions large-scale fluctuations, not reading; instructions not to zero; small flow without instructions; large flow instructions can also, on the instructions not allowed to flow ; flow changes failed to keep pace with changes in direction; Instruments K-factor can not be determined, information on various inconsistencies.

The main problem analysis and solution

The analysis of these issues and resolve to spend nearly six months time, because of complicated issues, a juice from the installation, setting parameters, routine maintenance and operating environment there are different degrees of problems, many of the issues involved in each other, together with some of the settlement of the issue We need to wait for the operation of the time, the solution to the problem has brought great difficulties. Some of the problems are different from the common cause of several reasons, some with a variety of reasons are several issues related.

Summing up the main cause of these problems, mainly related to the following:

(1) Selection of the problem. Some vortex sensor in diameter in the design or selection on the selection after due process of change, make a big choice - of specifications, the actual selection to choose the diameter as small as possible to improve the measurement accuracy, in this regard mainly because of the same Problems , , relevant. For example, a vortex pipeline designϹseveral devices, as part of the non-use of equipment sometimes, the actual use of the current flow decreases, the actual use of the original design Selection diameter is too large, equivalent to a measurable increase in traffic Threshold, when the flow of small pipes can not guarantee that direction, the flow also can use, because if too difficult to re-transformation of (sometimes. The process of change is only temporary). The combination of parameters can be re-tuning to improve the accuracy of instructions.

(2) Installation of the problem. Is the main sensor in front of the length of the straight enough, impact measurement accuracy, in this regard mainly because of problems with the relevant . For example: on FIC203 straight in front of the sensor is obviously insufficient, because FIC203 not used to measure, solely for purposes of control, it now can use the precision (equivalent to demotion).

(3) parameters for setting the direction. As parameter error, leading to instrument instruction is wrong. Parameters makes the wrong instrument for the second terms of frequency of errors, in this regard mainly because of problems with , relevant. Man of the frequency of almost not allowed to make long-term direction, the actual degree of frequency for the full Daegan terms of the frequency of large-scale fluctuations in making instructions, not reading, and information on the parameters of inconsistency also affected the parameters of the final set, finally passed Re-calibration compared with the parameters determined to solve the problem.

(4) secondary instrument failure. This part of larger failures, including: a dashboard disconnection of a circuit board, set a range of individual display bad, K factor set a bad individual display, made it impossible to determine range settings and set K-factor, Partly due mainly to problems , relevant. Through repair the corresponding failure, the issue is resolved.

(5) four-way line connectivity issues. Of the loop line connecting the surface, very good, double-check, and some have loose joints actual circuit caused disruption, although some joints connecting a tight line but because of problems securing screw fastening it in a line on the skin, but also makes circuit interruption This part of the main reasons for the same problem relevant. The corresponding lines to solve problems, the problems resolved accordingly.

(6) Secondary Instrument Instrument connection with the follow-up question. As the issue of follow-up instrument or instruments because of the follow-up maintenance, making secondary instrument mA output circuit interruption, for this type of secondary instrument, with the main reasons for this part of the problem . Especially for the follow-up recording devices to record in long-term damage beyond repair for the circumstances, must pay attention to two meters short of the output.

(7) As the second-axis meter cable fault circuit always caused no instructions. As long run, coupled with the dust under the influence-axis cable fault caused by cleaning or replacement of wire-axis, the issue is resolved.

(8) the problem was mainly due to secondary instrument table shows the first coil fixed Lo Si Song, the head table sink, Case friction with the guidelines, moves failed, by adjusting the head table and re-fixed, corresponding to resolve the problem.

(9) the use of environmental problems. In particular, is the installation of sensors in some of the wells, due to environmental humidity, causing circuit boards exposed to moisture, this part of the main reasons for the same problem , relevant. Through technological transformation of the corresponding measures, some of the environmental humidity sensor to a large part of the probe and the conversion of the separation handling, switching to the separation of sensors, Gushan the working environment, before this instrument is operating well.

(10) because of poor adjustment at the scene, or due to adjustment of the actual situation after the change again. As the scene vibration and noise and adjust balance of sensitivity adjustment bad. Or because of adjustment after a period of time after running the scene changes again, resulting in instructions, which in part because the main problem with , relevant. The use of oscilloscopes and the combination of performance, re-adjustment.

(11) reason for the problem of separate, long time on this issue in the impact analysis to solve the problem, because the East does not have chemical plant K factor calibration conditions, K factor can only be based on the information provided by manufacturers, as manufacturers themselves Some of the changes, causing several to provide information on the K factor is not - to influence the issue is resolved. Find conditions through re-calibration, or through repeated changes contrast, before deciding on the final reunification of the instrument parameters.

Through a period of careful analysis concluded that the vortex can be basically solved the problem, this instrument is operating well, basically meet the needs of factory production process.

Aggregate

(1) As the K-factor in the determination of the entire link Vortex in very heavy play, K coefficient of the accuracy of a direct impact on the accuracy of the loop, replacement parts and instruments of the wear and tear, such as pipelines, are factors that may affect K . Dongfang Chemical Plant and also the lack of demarcation of the means and ability, can only submit calibration, the operation of the impact on the pipeline removed from the Vortex sent to the demarcation of five or six days time, to meet the technological aspects, which can not be K-factor identified. This year, the flow through the instrument of the transformation, although already has a smaller diameter of Vortex calibration conditions, but for larger-diameter vortex still powerless, the future should pay attention to the use of the Vortex field calibration methods, the use of standard frequency and portable ultrasonic Flowmeter, measured in the pipeline and the instantaneous flow sensor output frequency of the pulse, calculated at K-factor.

(2) regular cleansing of the vortex flowmeter probe, inspection had found that detection of individual probe dirt hole has been plugged, and even plastic sheeting Guozhu, and affected the normal measurement.

(3) regular inspection grounding and shielding, eliminate outside interference. Sometimes the problem is due to direct interference Suozhi.

(4) the installation of the probe and humid environment. Drying should be a regular, or moisture-proof handle. As at the end of the probe itself to deal with moisture, exposed to moisture after the impact of running.

(5) instrument data management attention should be paid enough attention to in order to facilitate the work ahead.