Coriolis Flow Meters

I’m often asked whether Coriolis meters can measure mixed gas/liquid streams accurately.  Unfortunately, the answer is not a simple yes or no. This is due to the volume of published material that offers information regarding (varying levels of) success in mixed stream measurements, but the limits of measurement are often vague and results specific.

Rheonik meters are tolerant of entrained bubbles, but issues with accuracy can still arise. 

I can only speak to Rheonik meter performance, but from my experience, Rheonik meters are fairly tolerant of entrained bubbles, provided they are evenly distributed (e.g. foams are measurable because they are homogenous). However, accuracy will suffer—gas is compressible, and the movement of the tubes oscillating side to side will serve to compress the bubbles ever so slightly, so measurement will be affected (and potentially “noisy”) as they compress and decompress. The more gas, the more likely inaccurate readings will occur.  It is difficult to quantify what that change in accuracy will be in a given application, because different applications react in different ways.  

The good news is that density measurement will drop when bubbles are present. This drop is a strong indicator of their presence; it tells us what’s happening and indicates when accuracy may be suffering.  Keep in mind that bubble regimes in a pipe can vary dramatically, from light bubbles all the way through slug flow and at some point, pretty much all Coriolis meters will fail to measure flow with any degree of reliability and usually end up in a fault condition. 

Why are Rheonik Coriolis meters better at handling flows with entrained bubbles?

It really comes down to the unique mechanical construction of Rheonik meters.  The mechanical construction uses a design that provides support for the measurement tubes rather than just letting them “dangle.”  This alone improves performance when internal (pulsing/aeration) and external (vibration) disturbances are present.  The drive method is torsional (rather than the solenoid style “bang-bang” drive in meters with unsupported tubing) and this ensures that there is positive drive force on the mechanism while it’s oscillating all of the time.  The torsional nature of the drive along with the structured support for the measurement element means that Rheonik meters are typically better than most when measuring flow with entrained bubbles and therefore tend to go into fault less than other brands. 

Some meters use electronic means to improve performance in mixed stream flows.  Those electronic means range from masking meter fault condition by holding current value when it all gets to be too much to tweaking drive power and frequency in an attempt to keep up with the changing meter conditions.  These work to end users satisfaction in many cases, but it is important to bear in mind that no one can handle erratic or slug flow situations in a Coriolis meter to the same accuracy as seen with single phase flows.

Rheonik transmitters have a feature called PFPM (partially filled pipe management) that can help when the flow regime gets too difficult.  

The PFPM feature watches the reported density value (as one input while in operation) and should it drop below a preset threshold value or should the meter go into fault, the meter can be set to hold its current reading until it either reestablishes density above the threshold or times out. If bubble events are transitory, or even if there is a baseline aeration that worsens from time to time, PFPM can help mitigate bubble effects on the meter and therefore plant operation.  Bubble events can often show up at the beginning or end of a process operation, when flows are lower, so the overall impact on accuracy is small.  For operations where aeration is consistent, calibration factor adjustment can be used to correct for ongoing errors.

PFPM is a standard feature on all Rheonik meters with live density measurement capability and can certainly provide improved performance in difficult applications.  It is also useful in detecting and reporting deteriorating measurement conditions—for instance, when reaching empty in a feed vessel—so action can be taken by operators or control systems before they become a problem.  Coriolis meters equipped with advanced diagnostics capability such as Assurance Factor® diagnostics can be used in this way.  With Assurance Factor®, it’s also possible to get a continuous readout of measurement quality so that events like increasing aeration are spotted and resolved before they become an issue.

A few other ways to try to improve bubble interference issues in Coriolis meter installations are:

1. Increase back pressure on the meter if possible.  This helps keep gases dissolved in the stream so they aren’t such a problem.
2. If possible, install meters upstream of pumps or other equipment that might be causing the gas bubbles to form or be present in the flow.
3. Change the meter orientation so it is in “flag” mode—inlet at the bottom, outlet at the top.  Doing so can help prevent bubbles gathering at the high spot when entering the meter and creating slugs. This is not applicable in all situations.

Finally, thinner liquids with gas bubbles are tougher to measure than thick liquids.  Highly viscous flows, if aerated, tend to stay in the same state because the bubbles can’t “escape” through buoyancy or coalesce together to form larger bubbles as easily.  Provided bubbles are not slug-like in these situations, it shouldn’t be a problem to measure flow to reasonable accuracy.

Choice of meter is important.  Always check out the available bubble effect mitigation features as part of the process of choosing a flow measurement solution for your process. Please feel free to contact us if you have any questions about the applicability of Rheonik Coriolis meters for your operations.

Machines for mixing and delivering two-part (or more) chemicals for paint and adhesive coatings in industrial manufacturing plants must be accurate and reliable if the quality of the final product is to be maintained. High performance pumps are used to combine various chemicals in a predetermined mix ratio that are then delivered directly to the production line. Any unintended or unnoticed change in the proportioning of these chemicals being mixed can have a large impact and be very expensive in terms of rejected or off-spec product that often cannot be reworked.

Manufacturing plants have limited space, resulting in the installation of gear meters with small footprints which quickly lose accuracy due to wear and tear.

While metering pumps are generally very reliable—and their throughput is well correlated to their speed of operation—it is common practice to fit a flow meter in line with them to provide flow rate feedback. This is done to confirm that the desired amount of material is delivered, as over time pumps will wear and their delivery versus speed will change slightly. The flow meter also provides an independent indication should there be an issue, such as blockage or leakage, in the flow line.

In any manufacturing facility, factory floor real estate must be maximized in terms of the final product(s) output potential. To meet this goal, machinery is designed to be compact, and paint and adhesive preparation machines are no exception. Often purchased in skid form from specialist suppliers, a great deal of piping and components are crammed into a small space and when it comes to flow meters, those that are small, handle high viscosity liquids and do not require long upstream/downstream straight runs are greatly preferred. Gear meters have been the meter of choice for many of these machines in part because of their ability to handle high pressures, but also because they meet these requirements while having reasonable accuracy. The downside of using gear meters is that they are mechanical devices and as such, are affected by the same issues as metering pumps. Blockage, leakage and mechanical wear will, over time, cause measurement drift.

Gear meters give good performance when new, but they must be maintained if they are to continue to provide that same performance over long periods.

Unfortunately, maintenance is typically reactive rather than proactive and only happens after a problem has occurred. When problems occur with a gear meter, the most likely cause is debris or foreign particles in the process line. Foreign particles become enmeshed in meters’ tight tolerance gears, causing wear and increasing resistance to flow.

Large pieces of debris can cause the meter to seize and stop working altogether. Foreign material can be introduced into a meter in a variety of ways: a quality issue from the fluid supplier, an upstream component—such as another pump—failing, or as a result of an unrelated repair task in upstream piping. Whatever the source of the foreign material, whenever such a problem occurs, the meter must be disassembled, and its internals inspected for damage.

Should “chips and dings” or score marks in the gearing be observed, then the rotors must be replaced to ensure integrity and accuracy. Also important is to ensure that the measuring chamber walls have not been damaged as this may further contribute to operation issues. In almost all instances, damage to the measuring chamber will require replacement of the flow meter. While the meter is being repaired, the production line is down.

Even when gear meters are not exposed to foreign material, over time, bearings can fail and rotors potentially crack. Unless the failure is catastrophic, the only indicator of a problem would be a change in tone or an increase in noise level when the meter is operating.

Compact Coriolis meters are a superior modern alternative to gear meters in applications where space is at a premium.

Like gear meters, Coriolis meters require no upstream/downstream straight pipe run, but have the distinct advantage of having no moving mechanical parts and being immune to the effects of foreign material passing through them. Furthermore, the availability of advanced diagnostic information from Coriolis meters allows maintenance to be proactive. Diagnostic messages can alert users to deteriorating performance in the process before failure actually occurs.

But the adoption of Coriolis meters by fluid handling and mixing equipment manufacturers has been limited, in part, by their pressure handling capabilities and perceptions that they are high cost.

Newer Coriolis models, like the Rheonik L series sensors feature high pressure (up to 20,000psi) and high temperature (up to 350°C) variants, greatly increasing the applicability of the technology in industrial applications. Machine and skid builders can use these high-performance, low-maintenance units with their multi-functional performance to enhance value to their customers. For corrosive material measurement applications, Rheonik Coriolis meters can be configured with a wide variety of exotic wetted materials more cost effectively than gear meters, and Coriolis meters have the distinct advantage of being able to measure both viscous and non-viscous materials to the same accuracy.

With the availability of smaller, more compact Coriolis flow meter bodies and small remote electronic units suitable for DIN rail mounting, the advantages of using Coriolis meters as an embedded component in paint and adhesive mixing equipment can be easily realized. Coriolis meters provide increased value to produced goods through increased quality and consistency while saving cost through higher machinery uptime and lower maintenance requirements while their incredibly small footprint allows for even more compact process skids, maximizing the use of available factory floor space.

Bitumen is one of the heaviest and most viscous products produced in refineries. It is created from “vacuum bottoms,” the asphalt-like residue extracted from the bottom of vacuum distillation columns.

Bitumen is a long chain hydrocarbon molecule and appears to be solid at ambient temperatures. However, bitumen is really a highly viscous liquid and does “flow,” though only very slowly. Heating bitumen causes it to soften and eventually become a runny liquid at high temperature. This property of bitumen, near solid at ambient temperature, but liquid at higher temperature, together with its adhesive and waterproofing qualities, is the reason why bitumen is so useful in construction. Most bituminous coated materials are workable when mixed and applied hot, but on cooling become solid. While bitumen is best known for its extensive use as a binding agent in road asphalt, it is also used in the roofing and carpet industries, as well as for making sheets of corrugated papier-mâché water repellant. Many of its uses require unique hardness properties, so there are many different grades of bitumen produced. Different grades are made at refineries by blowing oxygen through bitumen to make it harder when cold.

The measurement of bitumen flow is notoriously difficult because of high process temperatures and viscosity conditions. Conventional meters are challenged with this measurement and failure is a common problem. Rheonik ET and HT mass flow meters are ideally suited for the task:

• High temperature ratings to 350°C/662°F
• No moving parts to wear
• Built-in trace heating jacket options
• High intrinsic accuracy and measurement stability, even at larger sizes

Steam purging for cleaning purposes will not damage meter internals, nor will over-temperature conditions. Wildly changing fluid properties caused by small variances in temperature are automatically compensated for. The use of Rheonik Coriolis mass flow meters significantly increases measurement reliability while dramatically reducing the maintenance costs often associated with other meter technologies, such as differential pressure devices and mechanical meters. Product quality and consistency are consequently improved, leading to less waste and rework, and greater plant productivity.

Rheonik meters can be used throughout bitumen process operations for a wide variety of applications:

• General process metering
• Batching
• Blending
• Coating
• Packaging
• Truck and railcar loading.

All Rheonik meters are suitable for hazardous area installation and operation and are simple to implement and use.

In offshore oil and gas fields, deep water developments are producing high-pressure, high-temperature (HPHT) wells with standard operating conditions that are pushing 20,000 psi (1,378 bar) and 360°F (182°C). In addition, subsea systems are creating exceptionally long pipe runs from wells to gathering points. Some well heads can be as much as 60 miles (100 km) from the platform. High-pressure operation is essential to overcome friction losses within the pipelines.

HPHT wells require the continuous injection of chemicals to avoid production interruptions, but these chemicals are extremely costly.

HPHT wells, like their lower pressure counterparts, are highly susceptible to a wide variety of conditions that can affect production rates and equipment reliability. Such wells require the continuous injection of chemicals to prevent conditions such as hydrate formation, asphaltene/wax buildup, line corrosion, and scaling. Left unchecked, failures will occur, and these can be expensive in terms of both repair/resolution and lost production.

Chemical injection systems (skids) are commonly installed in production facilities in the oil and gas industry. They are used to deliver a customized cocktail of chemicals to prevent and mitigate a wide range of downhole problems that can negatively affect production flow from wells. Production chemicals are expensive and can account for up to 30% of the day-to-day running cost of a production platform. Metering is a vital component of chemical injection systems as it is important to monitor and deliver the right dosage at the lowest possible cost.

Metering for offshore chemical injection systems has traditionally been provided by mechanical gear meters because of high-pressure rating requirements. However, the tight mechanical tolerances within gear meters cause seizure when particulates are present in the flowing chemical stream, making them a highly maintenance-intensive item. Furthermore, internal wear over time creates measurement inaccuracy, even more so with low-viscosity materials, as they will easily pass through the meter where it is worn and not be properly registered.

Given the high cost of chemical usage, there are great advantages to be found with chemical injection system metering solutions that are low maintenance and have no moving parts to wear.

Rheonik meters are ideal for chemical injection applications and are trusted in high-pressure installations around the world.

Rheonik mass flow meters offer the right balance between capital investment (CAPEX) and operating costs (OPEX). Key features of Rheonik flow meters include:

• The only flow meters with pressure ratings up to 20,000 psi (1,378 bar)
• Low flow capabilities down to 0.0004 lbs/min (2 g/min) with exceptional accuracy
• Corrosion-resistant wetted material options (316L, SuperDuplex, Hastelloy)
• Wide variety of process connections (including autoclave MP and hubs)
• Resilient to pump pulsations
• Low maintenance due to having no moving parts
• Useable in hazardous areas
• Supplied with build-in detailed diagnostic capabilities
• Cost effective and space efficient

Rheonik meters can currently be found in such subsea applications as:

Production Chemical Injection

Using Rheonik Coriolis flow meters in high pressure production chemical injection systems helps guarantee flow assurance requirements are met in pipeline and process equipment, optimizing processes in production operations. Chemical injection systems deliver flow assurance chemicals into production wells to prevent wax, asphaltene and scale buildup, and to improve flow of oil from the well. In addition to flow assurance, production injection systems also deliver chemicals used to protect and prolong the lifetime of pipelines and associated equipment by reducing and removing undesirable substances that can create failure modes.

Rheonik flow meters are fitted to accurately measure the dosage rates of chemicals such as corrosion inhibitors, biocides, demulsifiers, drag reducing agents, and foam inhibitors.

Produced Water Treatment Chemical Injection

When extracted from the ground, crude oil and natural gas are accompanied by water. The water/oil and water/gas ratio seen from wells gradually increases over the life of the well. The implementation of modern secondary and tertiary recovery processes has also increased water content in recovered fluids.

Chemical injection systems provide a convenient solution for adding chemicals like biocides, antifoam agents, deoilers, demulsifiers, nitrate inhibitors, and (sodium) hypochlorites to treat produced water prior to reinjection into a reservoir. Rheonik flow meters are used in those systems to accurately monitor chemical addition rates on the high-pressure side of the injection pumps, saving wear and tear on what can be expensive and critical components in the system.

Hydrate Control

Gas hydrates are crystalline structures that can form during natural gas extraction. Hydrates attach to the internal surfaces of pipelines and inline equipment, reducing (and eventually blocking) the effective cross-sectional area in flow lines and gas handling equipment. Typical chemicals used to control hydrate formation are methanol, MEG and LDHI / KHI. High-pressure Rheonik meters are available to measure hydrate inhibitors from drip feed rates to full flow rates in 2” lines.

Contact South Fork Instruments today to learn how Rheonik’s high-pressure Coriolis flow meters can drastically reduce your HPHT well operating costs.

From the outside looking in, the Coriolis flow meter industry looks quite diverse, with seemingly dozens of players involved. However, a closer examination reveals that the industry is quite small, largely defined by the innovations of a couple of manufacturers. Other manufacturers ostensibly “choose a side” by emulating the established designs of those industry leaders.

We don’t hide the fact that we only develop measurement solutions based on Rheonik brand Coriolis meters. We hope that by providing some insight into the industry, we can better explain why we choose Rheonik over all others.

 

TOP 3 CORIOLIS MASS FLOW METER MANUFACTURERS BY MARKET SHARE

 

Micro Motion / Emerson

Emerson Electric is an enormous international conglomerate which seeks out large projects for which they can package together as many instruments produced by their stable of subsidiaries as possible, to complement their plant control systems.

Micro Motion, founded in the 1970s was one of the first manufacturers of Coriolis flow meters, and in fact invented and patented the bent-tube design which long defined the market. Micro Motion was acquired by Emerson, and at one time controlled 80% or more of the market. However, that share has been eroded over the past decade, as their meters rely on a design that is approaching 50 years in age, and has been since surpassed. Emerson/Micro Motion controls roughly 45% of the Coriolis flow meter market now.

 

Endress+Hauser (E+H)

Endress+Hauser is a Swiss-based instrumentation conglomerate. A couple decades ago, E+H developed a semi-bent tube design, and specifically sought to leverage this in the development of their Promass instruments. With this new design, they went after a chunk of Emerson’s market share, and were successful in these efforts. They are now the second largest Coriolis flow meter manufacturer in the world. Interestingly, several Micro Motion patents ran out recently and E+H almost immediately released new models that have a Micro Motion-style bent-tube design.

 

KROHNE

KROHNE is another conglomerate, based in Germany, which develops and supplies instrumentation solutions in a variety of industries. They have made a name for themselves in the Coriolis flow meter industry for their straight-tube designs. Their marketing efforts have made them probably the third-ranking player in the market. However, the design has some shortfalls due to the inherent nature of how the Coriolis effect works (in short, the use of curved tubes helps to magnify the measurement of tube distortion and obtain more accurate measurements, a benefit their straight-tube design lacks). But KROHNE’s meters are quite low in cost, and this has helped them subsume maybe 10% of the global market.

 

RHEONIK – WHAT MAKES THEM DIFFERENT THAN OTHER CORIOLIS METER MANUFACTURERS?

Rheonik is a standalone company that makes only Coriolis flow meters. Their products cover the full range of needs, from extremely low flow laboratory equipment to massive meters for industrial and petrochemical applications. Because of this specialization, they are also only company innovating new designs alongside investing in improving upon past designs. For instance, they have recently introduced new Coriolis flow meters that can operate in high pressure applications (up to 20,000psi). Past innovations have included high temperature operation and exotic materials of construction, along with great flexibility in process connection sizes and types for demanding niche applications.

In addition, the Rheonik isn’t constrained by the need to adhere to a corporate look and feel. This means that their meter designs can be user intuitive, and housings can be made to fit a specific purpose, rather than being adapted from housings used for other instruments “for cost reasons.”

As you can see in the above descriptions of the companies currently dominating the Coriolis flow meter industry, none of the ‘big names’ are specialists—they are conglomerates invested in many different industries and types of technology. Their mass flow meters are a part of a vast catalog of often unrelated products. The result has been industry-wide stagnation.

These companies can afford to barely squeak out a profit on their meters, but this doesn’t allow or drive them to invest in improving their underlying meter technology. This is evidenced by Siemens—they invested heavily in meter manufacturing, and ultimately sold that capability off when they couldn’t earn back their investment. Micro Motion’s stagnation—and subsequent loss of market share—is also a product of their parent company, Emerson, having to tighten the belt and not invest in their products.

The marketplace is being dominated by falling margins and products which exist to fill a place in a product catalog. With low-cost meters flowing in from China, we expect to see a lot of turmoil and consolidation in this space. Companies entering this market are lured by reports of rising adoption of Coriolis flow technology across all industries and while it is true that Coriolis meter sales is a growing sector, companies who come into the market with me-too products are just not making inroads against the established players. Those who innovate are able to establish themselves in markets where others are not present

Nobody can keep up with or duplicate Rheonik’s efforts, because they can’t afford to. Rheonik Coriolis flow meters are truly unique in terms of their quality and range of applications, and that is why South Fork Instruments relies solely on Rheonik for their mass flow measurement solutions.

But if you’re still curious as to what other companies are currently active in the Coriolis flow meter industry, below you can find brief descriptions of just about every other company in the world that manufactures or markets Coriolis meters.

 

SECONDARY & TERTIARY CORIOLIS METER MANUFACTURERS

 

ABB Group

ABB Group is a very large Swiss company operating in multiple fields, including electrical infrastructure, electrical motors and generators, robotics, and more. While their Coriolis flow meters are reasonably priced and known to work well enough, this represents a very small segment of their operations. Consequently, their support is lacking, and their sales network is in flux. Their current meter designs largely duplicate the efforts of Micro Motion and Endress+Hauser.

 

ALIA Group Inc.

Aliagroup is a 20-year old Indian firm which introduced their line of Coriolis meters around 2018. Initially, their products were copycats of Micro Motion designs, but they have rapidly improved their efforts and are considered perhaps one of the “better” Asian manufacturers of Coriolis meters at the moment. But the quality of their manufacture may be an issue, and support is often spotty at best with Asian manufacturers.

 

Badger Meter

Badger Meter is a manufacturer of a “me-too” Coriolis meter. Anecdotal information suggests that performance is so-so, but fortunately with a sales volume of near zero, there are very few companies saddled with their products. The company seems to be continually going through a significant amount of internal turmoil, and support for their meters is almost non-existent.

 

Brooks Instrument

Evidence of the rather intimate nature of this industry, Brooks Instrument is a spinout from Emerson’s Process Management subsidiary. Brooks manufactures the Quantim line of mass flow controllers and meters, which are only designed for very low flow applications. Their presence in the low-flow niche is why Micro Motion opted some years ago to not design low-flow meters in this range.

 

FMC Technologies Inc. / TechnipFMC

While the FMC Technologies name is still reasonably well known, in 2017 the company merged with Technip S.A., a French engineering company, forming TechnipFMC. FMC does not actually manufacture their own Coriolis meters, but instead rebrands meters manufactured by Endress+Hauser.

 

Graco

Graco—no relation to the Graco baby products company—is an American fluid-handling systems company that only produces a very limited range of small Coriolis flow meters. Their light investment in meter technology is due to their focus in paint solutions. The majority of their mass flow meters are incorporated into their own equipment.

 

KOBOLD Instruments

KOBOLD’s product line was previously developed and sold by Heinrichs Messtechnik, which KOBOLD bought out a few years ago. Before that, they did have a relationship with FCI but it’s not thought to have been very successful. Their meters are generally regarded to be at the bottom-end of the Coriolis product spectrum.

 

Malema

Malema exclusively produces laboratory-type Coriolis flow meters for the semiconductor and biopharmaceutical industries and they don’t play in the process market.

 

Omega Engineering

Omega is actually a catalog house which sells rebranded Coriolis flow meters made by other manufacturers under their own brand. There is often a fair amount of confusion about their products, as Rheonik prominently markets their ‘Omega tube design,’ and Omega Engineering uses the prefix ‘FMC-’ on their meter models, inviting confusion with FMC Technologies.

 

OVAL Corporation

OVAL is a Japanese company that manufacturers mechanical gear meters, as well as three models of Coriolis flow meters in varying sizes. While the company has been successful in Asia, they have little to no presence in the Western world. They have made some inroads into the development of high-pressure meters for hydrogen applications, specifically fuel cell car dispensing, but these high-pressure meters have not performed particularly well in the field.

 

Siemens Process Instrumentation

Despite the sheer enormity of the Siemens—they dwarf even Emerson—Siemens recently divested itself of its Coriolis manufacturing unit. The company invested millions into a state-of-the-art manufacturing facility, but could not make inroads into the mass flow meter industry—which really speaks to how impacted the market is, an issue which we will touch upon later.

 

SmartMeasurement

SmartMeasurement is a Taiwanese company which manufactures knockoffs of Micro Motions’ Coriolis flow meters. While they make cursory attempts to sell their products in the US and Europe, they can only really be found in Asia.

 

TASI Group – TRICOR/KEM/AW Gear Meters

TASI Group is a consortium of companies involved in measurement, manufacturing, and a variety of other industries. In the American Coriolis flow meter space, the company markets their Tricor brand flow meters with limited success. Their products are of average quality, but there are some mechanical concerns with their designs—in particular how their meter mechanisms have a risk of internal leakage due to the use of pipe connectors inside. But the company has made some efforts at improving their products by acquiring the aforementioned Siemens line of meters.

 

Yokogawa Electric

Yokogawa is a Japanese electrical engineering company. Their involvement in Coriolis flow meter manufacturing is somewhat limited as their line of products primarily serves to complement their overall product ‘basket’ In support of their DCS control system.