Home > Informasi > Coriolis Meter (Preliminary Study)

Coriolis Meter (Preliminary Study)

 

This post lists any information I got associated with what Coriolis Meter is. The first place I heard about Coriolis was in the office. I find this stuff interesting because it has high accuracy in measuring many variables even actually I just knew that this metering is well known (honestly, there are more interesting stuffs that I find interesting as well). However, it has a drawback that it doesn’t work well in a significant pressure drop. Let’s say it’s gonna be the preliminary study. I still don’t understand why it doesn’t work well in a significant pressure drop and is there anything that we can do to improve its performance in that condition? If there exists, then how many strategy and how significant the effect? So many question marks, that I need to find the answer. Thus, as I said before, below is the list of information I got. The red statement means a statement that need to be followed up. More information will be gathered step by step.

 

Coriolis Meter

Meter Coriolis
– Mass measuring device consists of a sensor, a transmitter and peripheral devices to provide monitoring, alarm, and/or control function.

– The sensor consists of two flow tube(s), the drive coil and magnet, two pick-off coils and magnets and the RTD. During operation, process fluid entering the sensor is split, half passing through each flow tube.

– The drive coil is energized causing the tubes to oscillate up and down in opposition to one another. (require picture and video illustration)

 

– Alat ukur massa yang terdiri dari sensor, transmitter, dan alat peripheral untuk pemantauan, alarm dan atau fungsi kendali.

– Sensor ini terdiri dari dua tabung aliran, kumparan dan magnet pengendali, dua kumparan dan magnet pick off dan RTD. Selama operasi, proses fluida memasuki sensor terbagi, setengah melewati setiap tabung aliran.

– Kumparan pengendali yang diberi energi menyebabkan tabung berosilasi naik dan turun bertentangan satu sama lain. (butuh gambar dan video)

How it looks like

How it works

– The pick-off coils are mounted on one tube while the magnets are mounted on the other. Each coil moves through the uniform magnetic field of the adjacent magnet as the two tubes move.

– The voltage generated from each pick off coil creates a sine waves representing the motion of one tube relatives to the other. When there is no flow, they are in phase. When there is flow, the induced Coriolis force the tubes to twist, resulting in two out-of-phase sine waves. The time difference in the sine waves is directly proportional to the mass flow rate through the tubes (at a fixed pressure)

– Kumparan pick-off dipasang pada satu tabung sedangkan magnet dipasang di tabung sisi lain. Setiap koil bergerak melalui medan magnet seragam dari magnet yang bertetanggaan sebagai dua tabung bergerak.

– Tegangan yang dihasilkan dari masing-masing kumparan pick-off menciptakan gelombang sinus yang mewakili gerak satu tabung relative terhadap yang lain. Ketika tidak ada aliran, mereka berada dalam satu fase. Ketika ada aliran, Coriolis terinduksi memaksa tabung untuk memutar, mengakibatkan dua gelombang sinus berbeda fase. Perbedaan waktu di gelombang sinus berbanding lurus dengan laju aliran massa melalui tabung (pada tekanan tetap)

The density of the fluid (ρ) is calculated from the frequency of oscillation of the tubes (f). (How??)

Kepadatan fluida (ρ) dihitung dari frekuensi osilasi dari tabung (f). (Bagaimana??)

 

Transmitter’s actions :

  1. Sending a pulse current to the sensor drive coil causing the flow tubes vibrate.
  2. Processing the sensor input signals, performing calculations, and producing various outputs to the peripherals devices (mostly pulse)
  3. Allowing communication with an operator or control system.
 

Fungsi Transmitter:

  1. Mengirim pulsa arus ke sensor kumparan pengendali yang menyebabkan tabung aliran bergetar.
  2. Mengolahan sinyal sensor input, melakukan perhitungan, dan menghasilkan berbagai ouput ke perangkat periferal (kebanyakan pulsa)
  3. Memungkinkan komunikasi dengan operator atau sistem kontrol.

Source of Operating Study : Appendix A of the API Coriolis Liquid Measurement Draft Standards.

Sumber Studi Operasi: Lampiran A Draft Standar Pengukuran Fluida Coriolis API.
 

It should be proven under conditions as close to normal operating conditions as practical. The result of a meter proving will be a new meter factor (MF). This MF may be entered in accessory equipment (preferences due to audit trail capabilities), the Coriolis transmitter or applied manually to the quantity indicated. It has also calibration factor from manufactures which is even adjustable but should not be changed.

 

Alat ini harus dibuktikan dalam kondisi sesama mungkin dengan kondisi operasi normal seperti prakteknya. Hasil dari pembuktian meter akan menjadi faktor meter baru (MF). MF ini dapat dimasukkan dalam peralatan aksesori (preferensi karena kemampuan percobaan audit), pemancar Coriolis atau diterapkan secara manual dengan kuantitas yang ditunjukkan. Alat ini juga mempunyai faktor kalibrasi dari manufaktur yang bahkan dapat disesuaikan tetapi sebaiknya tidak diubah.

Source : API Draft Standard, Measurement of Single-Phase Intermediate and Finished Hydrocarbon Fluids by Coriolis Meters.

Sumber: API Draft Standard, Pengukuran Single-Phase Cairan Hidrokarbon Intermediate dan Akhir oleh Coriolis Meter.

– Coriolis Meter presents number of advantages over other types of meters (accuracy: +/-0.1% and acceptable repeatability). It can measure mass flow rate, volumetric flow rate, density and temperature, and also can be used as bi-directional meter. Ease of installation and low maintenance, no special mounting, no flow conditioning, no straight piping requirement and no moving parts.

– The drawback is a significant pressure drop across the meter (unsuitable for an existing operation where additional pressure drop cannot be tolerated)

– Coriolis Meter menyajikan sejumlah keunggulan dibandingkan meter jenis lainnya (akurasi: + / -0.1% dan pengulangan diterima). Alat ini dapat mengukur laju aliran massa, laju aliran volume, kepadatan dan suhu, dan juga dapat digunakan sebagai bi-directional meter. Kemudahan instalasi dan pemeliharaan mudah, tidak ada mounting khusus, tidak ada pengkondisian aliran, tidak ada persyaratan pipa lurus dan tidak ada bagian yang bergerak.

– Kekurangannya adalah penurunan tekanan yang signifikan di meter (tidak cocok untuk operasi yang ada di mana penurunan tekanan tambahan yang tidak dapat ditoleransi)

Categories: Informasi
  1. August 21, 2011 at 10:01 pm

    thnks God!i really need this input lol ;( having a problem with my coriolis meter which giving us the negative reading even the flow direction is correct, no back flow.have no idea what else to look on to this to sort out this issue!help ;(

    • August 30, 2011 at 7:30 pm

      Hai there,
      My apologize for late response, Seems that you have solved the issues right now.
      Anyway, talking about negative reading,
      Please kindly advise if my understanding is not correct.

      Negative reading is presented by a peripheral device which might consist of programmable microprocessor. Thus, it seems that the first thing that we need to check regarding to this issue is the program or the formula inside the microprocessor.

      After ensuring that the microprocessor works well, then we can go through the physical devices (that might need more detail analysis) such as the tubes, coil and RTD

      Hope it can help,
      And please let me know your findings.

      Thanks,

  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: