Flow Meter Akurasi tinggi

Kesalahan terbesar dalam Penggunaan Flow meter adalah ketidak tepatan dalam memilih jenis, type atau model flow meter. Pembelian flow meter biasanya hanya didasrkan pada 2 kriteria saja, yaitu bisa membaca debit aliran ( bisa berfungsi) dan harga yang terjangkau. Sehingga saat beberapa lama flow meter digunakan yang terjadi adalah biaya maintenance yang tinggi dan tidak tercapainya tujuan dari pemasangan flow meter.

Untuk pengukuran Fluida yang sangat membutuhkan akurasi, dikarenakan proses maupun harga dari fluida yang mahal, biasanya di tuntut akurasi tinggi pada hasil pembacaan  flow meter . Ada beberapa flowmeter dengan berbagi jenis dan kelebihan serta kekurangan. Namun Begitu ada suatu flow meter dengan kemampuan akurasi yang sangat prima, dimana akurasi bisa mencapai 0.1% bahkan lebih.

Akurasi flow meter biasanya dalam pengoprasian tergantung pada setabilitas temperature dan stabilitas pressure dari aliran fluida. Perubahan pressure bisa juga mempengaruhi akurasi flowmeter begitu juga perubahan temperature akan mempengaruhi hasil totalizer dari volume fluida yang di baca oleh flow meter. Akurasi ini sangat penting khususnya jika flow meter digunakan untuk mengukur cairan yang harganya tidak murah, yang mengakibatkan selisih pengukuran bisa berakibat pada kerugian akumulasi angka yang besar.

Dengan kondisi dan karakteristik suatu fluida baik cairan maupun gas  seperti diatas sebaiknya menggunakan flowmeter jenis coriolis mass flow meter yang mampu menjangkau akurasi 0.1% atau dibawahnya. Beberapa keunnggulan dari coriolis flow meter ini adalah :

• Akurasi bisa mencapai 0.1% atau lebih baik lagi
• Repeatability : lebih baik dari 0.05%
• Tahan terhadap korosi karena material sensornya stainless steel
• Pperubahan temperature tidak mempunya pengaruh pada akurasi pembacaan
• Aman jika Fluida mengandung partikel solid atau kotor karena tidak ada bagian parts sensor yang bergerak/berputar sehingga bisa dikatakan free maintenance.
• Seting pembacaan dari mass bisa di setting ke volumetrik
• Cocok untuk di operasikan pada filling dan custody

Jika karakteristik fluida yang sangat korosif serta mudah berubah bentuk karena perubahan temperature saat peroses dan cukup asam sebaiknya menggunkan flow meter jenis coriolis mass flow meter yang secara langsung menghitung mass dari cairan, sehingga perubahan volume karena perubahan temperature tidak merubah hasil dari pengukuran flow yang lewat  flow meter.

Dikarenakan Coriolis flow meter menggunakan material stainless steel untuk type standart ini sudah bisa mewakili syarat industri pengolahan makanan yang menuntut kelas material food grade serta tahan terhadap korosi sehingga bisa juga dikatakan food grade flow meter

Sehubungan harga dari fluida yang sangat mahal maka Coriolis mass flow meter sangat cocok sekali guna mencegah dan mengurangi kerugian jumlah fluida dan turunanya, yang disebabkan oleh selisih perhitungan dan pengukuran sebab akurasi dari mass flow meter je nis coriolis ini mencapai akurasi tinggi yaitu 0.05% hingga 0.2 % tergantung spesifikasi yang di inginkan.

Karena Coriolis mass flow meter ini bisa di pesan dengan custem maka bisa digunakan untuk berbagai stadart dari stadart JIS, ANSI, DIN dan lainna begitu juga jenis material bisa juga digunakan untuk asam yang punya PH ekstrim, Temperature ekstrim dari -45 to +210°C. Dan juga bisa diaplikasikan pada pressure hingga 345 bars.

Berikut Karakteristik dan keunggulan Coriolis Flow Meter yang di produksi oleh Rheonik dari germany 

APPLICATIONS

• Suitable for virtually any mass flow application, such as: Batching, Dosing, General flow control, Injections, Filling
• Loading of boats, vessels, rail tank wagons
• High temperatures and other challenging applications
• Highly viscous media (low pressure drop and excellent performance at low flow conditions)
• Properly used for corrosive liquids and Low Flow 
• Properly used for beverages that require  food grade instrument

FEATURES

• The outstanding features include :  Suitable for pressure up to 450 bar
• Size : 1/4" - 12 " : 
• Measuring ranges : 0.002  kg/min to 25.000 kg/min ( depending on pipe size ) 
• Accuracy   : 0.1% and better
• Repeatability : better than 0.05%
• Optimised solutions for your batching operation
• Extra compact design with minimal space requirement
• EEx Approvals (i.e. ATEX, CSA, ...)
• Custody Transfer Approvals (i.e. PTB, NMI, ...)
• As heavy duty version available (increased wall thickness of measuring pipes for additional safety - 250 bar)

ADVANTAGES 

• No pressure effect – no deterioration of accuracy due to pressure changes by the patented Omega Shape
• Medium flow rates in combination with high operating pressure
• Patented torsion swinger design assures  most stable and drift free measurement,
• Increased signal to noise ratio by torsion swinger
• Longest life time and increased safety (low stress in welds and increased wall thickness against abrasion)
• No moving parts, practically no maintenance
• Removable connection block

Specification : 

• Typical measuring ranges : 0.002  kg/min to 25.000 kg/min
• Flow Accuracy :  0.1% and better
• Repeatability  :  better ± 0.05% of rate
• Density         :  better than  ± 0.001 g/cc
• Temperature   : -200 to +350°C 
• Pressure range : Measuring Loops max. 93 bar - max CL 600 / PN 40
• Material of Wetted Parts :
• 1.4571 / SS 316Ti (standard), 
• 1.4539 / SS 904L on request, 
• Hastelloy C22 on request
• Tantalum and Other material on request
• Housing : 
• Stainless Steel: 1.4301 / SS 304 ( standart) and  others on request
•  Protection class: IP 65 (Nema 4X) and higher on request 
• Electrical connection
• Junction box / aluminium coated (standard) IP 65 (Nema 4X) (Junction box in SS optional)
• Cable entry M25 x 1.5 (M20 x 1.5, ½" and ¾" NPT optional)
• Max cable length between RHM and RHE :
• 100 m (330 ft)
• 200 m (660 ft) only with factory approval
• Approvals
• ATEX (CESI 02 ATEX 053 X) : Ex II 1 G, EEx ia IIC T6-T1
• CSA (220705) Class I, Div 1 and 2, Groups A, B, C and D;Type 3
• Custody Transfer Approvals (PTB 1.32-97027224 and NMI TC 3382)
• PED according to directive 97/23/EC available
• 3A Sanitary Approvals
• Transmitter and Display mounting : wall mounting, Pannel Mounting, Rack Mounting
• Outputs :
• 2 analog outputs, 
• 1 frequency/pulse output 
• 3 digital outputs (Lt, +/-, error...)
•  Inputs :   2 inputs (hold, reset, zero)
• Power supply :   
• 230 VAC +/- 10% or
• 115 VAC +/- 10% or    
• 24 VDC 
• Cable entries:   4 x M25 x 1.5 - others optional
• Interface :  
• RS 422/485/232 - optional
•  HART - optional 
• Power consumption : < 15 W

Rheonik Mass Flow Meter RHM 20

Medium sized Coriolis Mass Flowmeter
The Rheonix Coriolis Mass Flow Meter model RHM 20 can measure flow rates up to 300 kg/min (660 lb/min) with temperatures in excess of 350°C and pressures up to 340 bar. This model is medium sized with true reliability for a versatile solution manufactured by Rheonik, the mass flowmeter experts.

Owing to its typical flow range (up to 300 kg/min) and wide number of variants, the RHM 20 is suitable for many applications.As with all other Rheonik meters, this model is based on the patented Omega tube design with increased signal to noise ratio.

This unique design, which offers excellent performance and reliability, has created the most satisfied customers worldwide. Unlike other mass flowmeter manufacturers, Rheonik corilis flow meter uses a patented torsion rod swinger with the Omega shape and support bars which results in high accuracy measurement, which is independent of pressure, even at very low flow velocities. The meter has also extremely good repeatability and high stability for critical applications.

Coriolis Mass Flow Meter RHM 04

Universal Coriolis Mass Flowmeter with particular Fast Response

The RHM 04 is an economical meter which has been in production for over 15 years. This meter has been optimized for applications which require extreme stability and fast response. As with all other Rheonik coriolis mass flow meters, this model is based on the patented Omega tube design with increased signal to noise ratio. 

This unique design, which offers excellent performance and reliability, has created the most satisfied customers worldwide. Unlike other mass flowmeters, Rheonik uses a patented torsion swinger with the Omega shape and support bars which results in high accuracy measurement, which is independent of pressure, even at very low flow velocities. The meter has also extremely good repeatability and high stability for critical applications.

The RHM 04 can measure flow rates up to 10 kg/min (21 lb/min) with extremely fast response times and excellent repeatability. A true solution, particulary for application such as batching where fast response times are needed, manufactured by Rheonik, the mass flow meter experts.

Coriolis mass Flow Meter

The Coriolis effect was discovered by physicist Gustave Gaspard Coriolis during the 1830’s, and is described as “the inertial force exerted on an object as a result of movement relative to a rotating frame of reference.” This science has been applied to many technologies: hydraulics, machine performance, missiles, ergonomics, ocean and atmospheric circulation and, of course, mass flow metering. 

 

Coriolis mass Flow Meter

 The use of the Coriolis effect as a technique for liquid and gas mass flow measurement was firmly established over 20 years ago. Since then, a number of different designs have been produced. With the tremendous electronic signal processing technology advances that have been made, Coriolis mass flowmeters have become highly accurate and reliable instruments. Rheonik remain at the forefront of this technology and now produce the world’s largest and most comprehensive range of meters. Only the Rheonik range has all of the following features:

• Liquid, sludge and gas measurement capability 
• Models to measure flow rates from as low as 0.03 kg/h up to 1,500,000 kg/h (0.07 lb/h to 3,300,000 lb/h)
• Sizes up to 12” / DN300
• Pressure ratings up to 900bar / 13,050 psig
• Temperature ratings from -255°C to +400°C / -425°F to +750°F
• Fiscal/custody transfer approvals (OIML R117 / NTEP)
• ATEX and CSA hazardous area approvals covering most of the world
• Extreme resistance to gas bubbles entrained in the process stream when compared to conventional Coriolis meters 
• Unaffected by viscosity, density or pressure changes 
• Multifunction measurement capability includes density and temperature 
• Available with stainless steel, hastelloy, monel and tantalum wetted materials as standard.Other materials on request

Operating Principle 

The flexibility of the Rheonik range in terms of applicability and accuracy is due to the patented mechanical arrangement of each meter. Each flowmeter has two measuring tubes parallel to one another and formed into the unique Omega shape, oscillating in opposing directions. 

The oscillating system is driven with two high mass cross bars mounted on vertical torsion rods:

1. The high mass cross bars stabilize the torsional movement, either eliminating or greatly reducing interference from external vibration and providing continued, reliable operation with the presence of oscillation dampening factors such as entrained gas bubbles or non-homogeneity in the process stream. 
2. The torsion rods minimize stress on the tubing, guide tube movement and help “energize” the torsional motion. 

This rugged mechanical arrangement is energy conserving and requires very little power input (typically less than 300mW) to maintain oscillation amplitude. The design provides for an exceptionally well balanced mechanism that approaches perpetual motion once energized, with a natural frequency that is tuned by the mass of the cross bars and the elasticity of the torsion rods.

Amplitude is controlled by a pair of electromagnetic coils mounted at each side of the Omega tubes. The whole mechanism is symmetrical, ensuring that internal acceleration forces from the measured process are counterbalanced. Whenever mass (either liquid or gas) flows through the oscillating Omega shaped tubes, a Coriolis force is generated, causing a “bending” or “deflection” in the top of the tubes. This deflection is sensed as a phase shift between two electronic pick ups mounted on the tubes. The degree of phase shift is directly proportional to the mass flowing within the tubes. 

This can perhaps be better understood by imagining that the oscillation of the meter measuring tubes (the upper semi-circle of the Omega tubes) is taking place on an imaginary disc with points “a” and “b” on the circumference of the disc. Process material, starting at point “a” and moving across the imaginary disc to point “b” (the path of “effective massflow”) will pass through a range of differing velocities along the way. The Coriolis force (“FC”) generated from the oscillations of the disc and the effective mass flow vector is perpendicular to the movement of the mass across the disc and is proportional to the mass flow. In the meter, this force causes the deflection that is sensed by the two pick-up coils. 

Rheonik Coriolis Flow Meter

The continuing need for more accurate flow measurements in mass-related processes (chemical reactions, heat transfer, etc.) has resulted in the development of mass flowmeters. Various designs are available, but the one most commonly used for liquid flow applications is the Coriolis meter. Its operation is based on the natural phenomenon called the Coriolis force, hence the name.

A coriolis flowmeter is a mass flowmeter to directly and continuously measure the “mass”, the only characteristic of fluid that is not affected by the change in temperature, pressure, viscosity, and density of it. Based on a unique principle utilizing Coriolis force, wide range of mass flowrate based system can be configured by detecting the mass flowrate in high accuracy and sensitivity and converting it to analog or frequency output. In addition to general liquids, flowrate of foods, chemicals, slurry, high-density gas, etc. can be measured. A major feature of the Coriolis flowmeter is a complex sensor that can measure

temperature and density simultaneously with flowrate.

Coriolis meters are true mass meters that measure the mass rate of flow directly as opposed to volumetric flow. Because mass does not change, the meter is linear without having to be adjusted for variations in liquid properties. It also eliminates the need to compensate for changing temperature and pressure conditions. The meter is especially useful for measuring liquids whose viscosity varies with velocity at given temperatures and pressures.

Coriolis meters are also available in various designs. A popular unit consists of a U-shaped flow tube enclosed in a sensor housing connected to an electronics unit. The sensing unit can be installed directly into any process. The electronics unit can be located up to 500 feet from the sensor.

Key Benefits

•  Highly accurate mass, density and temperature measurement
• Unprecedented, precise liquid/gas flow measurement without skips or stalls
• Fast startup — up to 10 times faster than conventional Coriolis meters
• Highly accurate batches, starting from empty tube

Key Capabilities

• Patented digital flowtube drive technology
• Dual and multiphase flow capability
• Start and finish batch from and to empty
• 16 millisecond true response time
• NTEP Certified (weights and measures) for custody transfer *Contact Invensys for special requirements
• HART and Modbus RTU protocols
• AC or DC power capability
• IP66/ Nema 4X
• Explosion– proof with IS connectivity between flowtube and transmitter
• Stainless steel and Hastelloy C (some sizes) construction 

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