Welcome to the Spring 2018 issue of fLowdown - a quarterly Newsletter from Titan Enterprises Ltd. written to keep you informed about the latest technological developments, applications advances and breaking news in the field of flow measurement.

If a particular feature interests you, do not hesitate to contact us or follow the link for further information. We welcome your feedback.

Trevor Forster (Managing Director)

 

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Trevor's
Technical Tip

Trevor Forster is Managing Director of Titan Enterprises. His experience in fluid handling dates back to the mid 1960's when he started working on rotating seals and flowmeter design for third party clients. Trevor draws upon over 40 years of using innovative design and production techniques to produce elegant flow metering solutions for organisations around the globe.
In this issue - Trevor offers you useful technical tips on:

Best Practices for Optimising Accuracy & Repeatability

Most people would agree, there is no point in buying a top of the range flowmeter if you are not getting the most out of it. From long experience my recommended checklist before investment should include:

  • 1. Specify the right flowmeter for the job.
  • 2. Carefully follow the installation instructions.
  • 3. Be aware of performance changes with shifts in the operational envelope.
  • 4. Do not kid yourself - all may not be what it seems.
  • 5. Be vigilant.

Specifying the right meter for the job

Any responsible flowmeter salesperson should ensure that you have the appropriate solution. Unfortunately following the advice of someone with just a cursory understanding of how the flowmeter works within your system can lead to performance difficulties later. Even if you believe you have made the perfect decision be open to questions about the various choices you have decided upon. Experienced engineers do normally make good judgements but their expertise is rarely in just one discipline. Do not be afraid to ask questions to your supply company, often the simplest ones are the most revealing.

Carefully follow the instruction manual

Unfortunately many people do not and pay the price later. This is one of my pet grumbles. I like buyers/engineers who read these instructions before even specifying the flowmeter for their application. Flowmeters are calibrated at the manufacturers facility under optimum installation conditions. If the specified performance is to be repeated the calibration set-up should be replicated as close as is possible. No pulsations in the flow, large lengths of upstream and downstream straight pipes with no changes in section close to the flowmeter. Definitely no elbows, valves, pressure regulators or filters. It is OK to make an exception on filters if you are considering a positive displacement flowmeter as these usually do not require straight pipe lengths, A filter fitted to the flowmeter inlet in a clean workshop prior to installing the whole assembly in the plant is good practice as any debris left in the pipes cannot get into the flowmeter. The alternative is to put a dummy length of pipe in the line and flush the whole system.

Be aware of performance changes with shifts in the operational envelope

A lot of flowmeters will change their output with changes in the operating conditions. Many are Reynolds number sensitive so changes in viscosity and density will alter the output. Turbine flowmeters are a good example of this. In the turbulent flow region (Re above ~2000) turbine flowmeters are linear devices and small changes can easily be accommodated but below this threshold the performance can sometimes drop off quite significantly. In other words, if you are likely to be operating around the minimum stated flow be aware of operational changes that may drop you out of the flowmeters linear region. Examples of this are temperature drops in slightly viscous fluids or flows dropping below the recommended minimum with a loss of pressure i.e. a tank running low. Are your secondary measurements like pressure and temperature accurate? There is little point in applying a correction to your flowmeter if it is based upon an erroneous secondary measurement.

Do not kid yourself all may not be what it seems

As mentioned above - has your secondary instrumentation been calibrated? If not it could be seriously misleading you. Is the pipework clear with no weld spatter or gasket overhanging into the bore? This will cause asymmetric flow which could cause undetected high or low readings.

Be vigilant

Keep a close eye on things. A flowmeter with good repeatability and resolution can highlight other weaknesses in the system. Why is it not reading exactly the same as yesterday or last week? While the reason maybe your flowmeter, it could just as easily be a faulty pump or regulator. Have the flowmeter inspected and calibrated at suitable intervals to maintain the performance.

Buy wisely, install intelligently and maintain responsibly and your flowmeter can give you years of accurate and repeatable service.

For further information please visit https://www.flowmeters.co.uk/ or contact Titan Enterprises for advice on your application.


Problem Solved

In this feature, we look to bring you examples of customer applications addressed by flowmeter development by Titan Enterprises.

STUDY: Monitoring Oil Flow to Critical Bearings in Heavy Machinery

Industrial crushers are used in a wide range of materials processing sectors which include aggregates, landscaping, infrastructure and road building, construction and demolition, mining, waste management and recycling.

To ensure reliable operation monitoring of lubricating oil flow and pressure to the main drive bearings in crusher units is critical. The specification for the required flowmeter included that it could not impede lubricant flow and had to have a low pressure drop even at full flow with cold, thick oil. While our standard OG5 flowmeter met the flow requirements the standard 1-inch diameter flow pathway was considered too small as it may restrict lubricant flow.

After initial successful proof of concept trials with the standard OG5 flowmeter, we redesigned the aluminium version of the meter to have 1.25-inch diameter connections to reduce the pressure drop at minimum operating temperature and maximum flow. In addition, a transparent cover was fitted to the flowmeter so that the operator could visually verify oil flow. Further customisation allowed the flowmeter to be plugged directly into the customers wiring loom and the body of the meter was even anodised to match the colour of the crushing machines they were being fitted to.

The resultant flow monitoring device has proved to be very reliable and to date nearly 500 units have been installed in the clients crushing machines. For further information on the IP67 / NEMA 4 compliant OG5 flowmeter please click here.


Product Focus

NSF Certified Flowmeters for use with Food Products

Increasingly food and beverage manufacturers wishing to meter production flow are requiring the assurance of accredited certification that the flow measurement devices they choose are completely compatible with their products.

NSF (www.nsf.org) are an independent, accredited organization, that test, audit and certify products to develop public health standards and certifications that help protect food, water, consumer products and the environment.

Titan Enterprises has recently achieved certification under NSF/ANSI 169 as equipment for food products for their 800 Series turbine flowmeters and Beverage meter. This accreditation is especially important for manufacturers of food production and handling machinery who can now include an 800 Series or Beverage meter secure in the knowledge that it has met NSF-standards for food production.

For further information on NSF certified flowmeters for use with food products please click here.


Humour

As we slowly move into what we hope will be a long hot summer here are a few bits of humour that we hope will make you smile.


Client: "How do you estimate how long a project will take?"
Engineer: "I add the time needed for each activity, then multiply by pi."
Client: "Why multiply by pi?"
Engineer: "It explains why my estimates are always irrational."


What makes a perfect early summer day?
A perfect summer day is when the sun is shining, the breeze is blowing, the birds are singing, there's a nice cold drink in your hand and the lawn mower is broken.

Flow Technology Spotlight

In this issue of fLowdown we look at:

Ultrasonic flowmeters – what are the limitations of the technique?

You may view this to be an odd article title coming from a manufacturer of ultrasonic meters but this is the real world. No liquid flowmeter is perfect, not even highly priced Coriolis devices. What are the drawbacks to this exciting flow measurement technology?

Attenuating fluids

No matter how good your ultrasonic flowmeter there are some fluids that ultrasound will have trouble travelling in. You can increase the gain in an ultrasound system but if the signal is weak this will also increase the background noise thereby reducing the flow range of the flowmeter. You could move the sensors closer together in the flowmeter design but as the distance between the crystals is directly related to the flow induced phase shift you are again reducing the dynamic range of the device. In some instances this may not matter as the basic technology has a wide flow range and restricting a little may not be a problem but this is not an option for standard products. For some badly attenuating fluids an ultrasonic flowmeter is not the answer.

Suspended air bubbles

This has a similar effect to an attenuating fluid. The bubbles act as tiny resonators and just absorb the ultrasonic vibrations. The size of the air bubble determines the resonant frequency so get exactly the wrong size and the result is little or no signal at all. Small volumes of a viscous recirculating fluid can carry gases in suspension so if you are designing a recirculation system you must ensure that enough volume of fluid is used to permit de-gasing. Separating inlet and outlet and ensuring gases are not introduced by “splashing” are good starting points. Large pockets of air will kill the signal entirely so an ultrasonic flowmeter is a near perfect air detector.

Pulsating flow

This is a problem with most types of flowmeter so it seems a little cruel highlighting it as an ultrasonic flowmeter problem. Any electronic flowmeter will have an operating cycle and should the frequency of measurement period coincide, or be at an unsuitable period, to the flow pulsations aliasing may occur. The result can be a signal (flow reading) that is far from reality. Imagine a cycle time of 100 Hz and an actual measurement period of 5 ms i.e. half the time, if the pulsations are at the same frequency and the peak of the flow is at the measurement period the reported flow will be too large. Conversely if the flow pulsation is exactly at minimum flow the reported flow will be too low. In-between and multiples of this example will also cause erroneous readings. Methods of removing pulsations are available to eliminate this problem but one of the lines of research Titan are following is a method of measuring accurately with these pulsations.

Limited range of speed of sound in the fluid.

Most ultrasonic flowmeter manufacturers will specify the maximum and minimum speed of sound in the fluid over which their meter will operate. This means that fluids with a very low or a very high velocity of sound might be problematical. For example, Water is typically quoted as 1482 m/s but many refrigerants are around 600 m/s and Glycerine 1920 m/s. To design an ultrasonic flowmeter that operates over this entire range without user input is very difficult. Titan has developed a system that will work at most speeds of sound in the liquid. This is not ready for release yet as we seeing a small amount of jitter (~1%) in the output which we consider unacceptable.

To discuss the best type of flowmeter for your application do not hesitate to contact us on info@flowmeters.co.uk or +44-1935-812790


How do I measure?

In this issue of fLowdown we discuss:

Measuring Low Fluid Flows of "Difficult" Liquids.

Often difficult liquids are thought by many to mean very aggressive chemicals but the term should also encompass hygienic and critical liquid flow applications.

Some processes require fluids that contain no free metal ions so an all polymer or glass flowmeter construction is necessary. Other applications, including drug production, silicon component creation, medical and food research or manufacture, require the flow line to have no inclusions or dead areas as this can contaminate the fluid in a number of ways.

In the Bioscience and Medical sectors, companies are trusted with supplying equipment which produces drugs and chemicals which are then given to unhealthy patients when their natural defences are at their weakest. These products are ingested, injected and applied externally, the production equipment must be ultra-clean and highly reliable.

In the electronics industry, the slightest contamination in micro-chip production can literally render thousands of dollars’ worth of product useless.

In the food and beverage sector, production line sterilisation is essential to ensure that no bugs remain trapped in any small cavities which can then multiply and contaminate the product produced.

In the water industry, the chemicals used for purification are highly oxidising and corrosive and therefore require very careful handling.

Over the years, a variety of flowmeters which comply with these requirements have been developed including all PTFE axial turbines, glass thermal devices, vortex shedding systems and lined electromagnetic or Coriolis meters.

For ultra-pure water and non-conducting fluid applications using electromagnetic flowmeter technology is often a non-starter. Coriolis technology is always expensive and the thermal glass devices are delicate, have limited performance and are fluid specific.

For larger diameter pipes a clamp-on ultrasonic flowmeter comes very close to providing an ideal tool for many of the applications described above as the velocity of the fluid is measured non-intrusively.

For small flows there is far less choice as these clamp-on ultrasonic flowmeters start to become inefficient below ½" pipe sizes. One of the most popular choices for these low flows are Pelton wheel (radial flow) turbines which can handle significantly lower flows than their axial counterparts. These meters handle the very low flow rates required and are manufactured in chemically resistant materials such as PVDF and even sometimes all Teflon constructions with sapphire bearings. The problem is that they still have moving parts.

The ideal 'difficult liquid' flowmeter would use an unbroken PTFE, or similar inert material, tube which did the metering operation and gave an accurate electronic output.

Following this ‘ideal flowmeter’ specification – Titan has developed MetraFlow® - an exciting new addition to our expanding ultrasonic flowmeter range. MetraFlow® uses our latest patented ultrasonic flowmeter technology to give a straight through geometry. The flow tube is just that - a chemically resistant PFA tube onto which are mounted high sensitivity ultrasonic sensors. There are no dead areas, changes in fluid direction or obstructions, just a tube.

For further information on the new MetraFlow ultrasonic flow meter please click here.


Flow Measurement Interview

Recently Trevor Forster was approached for a thought leader interview by the online publisher AzoNetworks. We thought you might be interested in reading his answers to questions on the topic –

'The expanding role of ultrasonic flowmeters
in fluid metering'.


What are the main reasons for people wanting to meter the flow of fluids?

TF There is no single main reason for wanting to measure flow but often the prime drivers are associated with control. Be it the control of processes, product quality, medical requirements, or people’s actions.

Processes: Flowmeters are used in a wide variety of processes from the measurement of crude oil and the small amount of additive chemicals employed to ensure easy and safe handling through to the mass air flowmeter in a car's engine to ensure a legal and economic combustion of the refined fuel.

Product quality: There are many examples of flowmeters being crucial to product quality. For example precisely metering the amount of a critical fluid used in the manufacture of a drug or simply ensuring that a coolant (or heating) fluid flow is keeping the process within operational parameters. Would you enjoy drink from the coffee machine if it was dispensed in different volumes with different strengths every time?

Medical: In the operating theatre anaesthetists have the technology to monitor the gases flow being administered to patients, sometimes the blood flow and now even the volume of a drug being supplied intraveneously. Kidney dialysis machines and numerous other pieces of medical equipment use meters. The amount of coolant delivered to a patient's scalp can reduce the amount of hair loss during cancer treatment but the flow rate (heat extraction) is controlled by a flowmeter and careful temperature monitoring.

Peoples actions: Currently government and utility companies are encouraging UK customers to install "smart meters" (gas, electric and water). This strategy is designed to make people aware of the wastage of these resources and so modify their actions. Tug operation companies fit flowmeters to prevent/inform the captains that jamming the throttles fully open for the often long trip back to harbour is very expensive. These vessels are about power not speed and operating them at full power just to go a tiny faster is a big mistake as there is very little speed increase for a an enormous increase in fuel being burnt. Pub companies install meters which not only measure the beer flow but also monitor the temperature of the beer and whether the lines have been cleaned so that they can ensure a good quality product for their customers. On a large scale the data collected will also provide a very valuable consumer behaviour report for future marketing exercises.

How do Titan ultrasonic flowmeters work?

TF There are two basic methods of ultrasonic flowmeter operation, Doppler shift and time of flight measurement.

Time of flight (as used by Titan) is the preferred technique for flowmeters as it returns the best performance. In time of flight ultrasonic flowmeters sound is injected into the fluid in which it travels with the flow until it is received further downstream. A signal is then injected from the received position which then travels back to the first transmission point against the flow. Because of the fluid movement the signal travels faster with the flow than it does against it. The phase shift between these two waveforms is directly proportional to the fluid velocity and the further the sensors are apart the greater the phase shift. As the pipe geometry is known so is the volumetric flow.

Doppler shift utilises the fact that sound traveling towards a receiver is accelerated whereas sound travelling away is slowed down. The classic example is a car approaching a listener. The engine note has a raised pitch as it approaches and a dropped pitch when it recedes. The amount pitch changes will depend entirely on the speed of the car as the sound waves are bunched up and stretched out more or less. If ultrasound is injected into a fluid stream it will travel until it hits something moving within the fluid that causes the sound to be reflected back to the source. As with the car the faster this reflector is moving the greater the increase in frequency when the signal arrives back at the transmitter. This system requires something to reflect the ultrasound back to the receiver which is usually impurities in the fluid.

Clamp-on ultrasonic flowmeters can be based on either operating system but increasingly are time of flight devices.

What benefits do ultrasonic flowmeters offer over other flow techniques?

TF The main benefits of ultrasonic flowmeters include:

  • a. Low pressure drop as the flowmeter bore is often the same as the pipe bore.
  • b. The ability to meter a wide variety of liquids as they are not dependent on fluid conductivity or Reynolds number unlike electromagnetic or mechanical meters.
  • c. High accuracy for compact assemblies. An accurate in-line ultrasonic meter can be quite short unlike a Coriolis meter of similar size.
  • d. Perfect for large pipes. A 1 metre flowmeter of almost any other type would be bulky. The equivalent ultrasonic device would have a number of transmitter receivers set on an angle on perhaps a 1 metre length of pipe with an associated electronic box.

For which industries and applications are ultrasonic flowmeters the tool of choice?

TF As I mentioned previously - traditionally ultrasonic meters have been THE meter of choice for large pipes. These can be multipath devices capable of extremely high accuracy. Ultrasonic flowmeters are trusted devices for fluid custody transfer as they are able to maintain their performance for long periods of time. Another important application is to ascertain the unknown flow in a larger diameter pipe (say 25mm and above) - the simplest way of doing this is to use a clamp-on ultrasonic flowmeter which can provide an invaluable diagnostic tool. This use of ultrasonic flow metering has resulted in very low flow (low accuracy) medical devices for monitoring blood flow in blood vessels during critical operations.

How have Titan improved ultrasonic flowmeter technology?

TF Simply by tearing up the rulebook and making ultrasonic flowmeters work well with low flows. This innovation is shown by the two patents granted to Titan Enterprises with further patents pending. Our development of unique algorithms and techniques has resulted in a new generation of low flow ultrasonic flowmeters that work well. R&D at Titan has even produced designs where we can send ultrasound round corners. The lowest flow ultrasonic device we have produced so far has a 28mm diameter loop of one and a half turns of 1mm bore tube. This device can accurately measure flows as low as 0.25 ml/minute e.g. delivering a spoon of medicine in 20 minutes. Recently Titan demonstrated an ultrasonic flow device for domestic water metering that which can detect leaks of just 25ml /minute from a 50 litre per minute flow meter. We are currently also working on methods of using ultrasonic technology to meter very high pressures small bore tubes which would not have been possible previously.

What services and support do Titan offer in addition to flow instruments and software?

TF Ninety-five percent of our business are repeat orders from satisfied customers, a fact we are very proud of. For larger OEM projects, we undertake consultative research and development for often several years to make sure that the measurement solution we are offering is ideal for their application. In such projects, we have the expertise, facilities and resource to design and test custom moulded products and be involved in pre-production and suitability trials. As flowmeter solution providers and we will tailor our existing products or completely design, test and tool a metering system for a specific application. Mid volume OEM's with a critical flow measurement requirement are our typical customers where a long term reliable product is required and a $1 device from the internet just will not do but a £3000 Coriolis meter is equally unacceptable.

What areas of research are Titan investigating to further develop their ultrasonic flowmeter technology?

TF As I mentioned earlier we believe we have the best small bore ultrasonic system in the world today. We have just launched the Atrato Metraflow meter which has a PFA tube with sensors attached to the outside of the pipe. This gives an ultra-pure fluid path and there are no disruptions or changes in section making the device ideal for critical material handling. Our current R&D effort is focused on low cost water meters and some derivatives for OEM use. These products will be low cost but the basic technology could be equally transferable to a smart water meter with remote reading and all the other good things that a non-mechanical electronic based device can bring. We have some new ideas for algorithms which will permit us to accurately meter small bore thick wall tubes at pressures up to 1000 Bar. We can already do this but have to compensate for several variables which the new system would make automatic. Clamp-on medical devices that deliver better accuracies that the current ±5% with a limited range is another system we want to perfect as this could be used in laboratories as well. I would like to see most of our mechanical products replaced with ultrasonic devices as I see this as the main future of flow measurement.


Bulletin Board

Innovation and R&D Investment

R&D is a company's life-blood. Without a consistent flow of new products - you risk your company going backwards. At Titan we are always researching new and better methods of measuring low flows. We believe that the future of low flow measurement is in time of flight ultrasonics and to that end we are continually experimenting with new operational systems and sensor configurations.

We have one patent for which we have exclusive global rights, two further patents granted and a further three in application. To add to this tally we are in the process of preparing two new applications for future research. This level of commitment to moving the technology forward is an indication of our belief in continuous product development and improvement. With the latest research we are in a unique position to be proactive with changes in low flow requirements in the future for both standard products and custom solutions.

To discuss an OEM solution for your small bore flow application click here.

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Titan Enterprises Ltd, Unit 2, 5A Cold Harbour Business Park, Sherborne, Dorset, DT9 4JW. UK
Telephone: +44 (0)1935 812790   -   Fax: +44 (0)1935 812890   -   Email: sales@flowmeters.co.uk