Welcome to the Winter 2017/2018 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)

 

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:

Trouble-free flowmeter installation

This is a little like house buying - location, location, location except in this case of choosing and installing a flowmeter you should look at specification, specification and specification. Get this wrong and you will never attain a trouble free installation. After careful consideration of application parameters including flow, pressure, fluid type and properties plus required function you should look at proposed installation location for your flowmeter and take note of its full operational envelope. Always read the manufacturer’s instructions prior to even specifying a flowmeter as this may change your requirements if certain recommendations cannot be accommodated.

Often you will have to make a compromise as illustrated with these real-world examples experienced by Titan customers.

  1. A low-cost turbine flowmeter was first considered as it could make the required measurements easily, unfortunately the installation would be very convoluted as no straight lengths of upstream and downstream pipework were possible. This would result in unreliable readings so in this case a positive displacement meter would be a far better option. The initial outlay may be higher but the long term installed cost and performance will be well worth the outlay.
  2. Metering the flow of fluid at up to 60°C maximum was fine but one customer found siting the flowmeter in their preferred location right next to a furnace with radiant temperatures well above the meters specification made that location unsound.
  3. With one installation we had repeated turbine flowmeter failures even though the application was well within the flowmeters operating limits. It transpired that the customer had put the flowmeter at the end of a very long pipe run which drained down completely every night. On start-up the fluid pushed a vast quantity of air at high speed in front of it. This spun the turbine to excessive speeds which was then met with a slug of fluid which would rotate the impellor at a much lower RPM. An overspeed is bad news but when followed by a rapid deceleration it is even worse. Installing a simple non-return valve prevented the system from draining down and made the flow-metering reliable.

For further information please visit click here or contact Titan Enterprises for advice on your application.


Problem Solved

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

STUDY 1: Metering grease lubrication flow in a wind turbine

In this case study we report on how Titan Enterprises developed a highly reliable flowmeter to monitor the lubricating grease being supplied into a wind turbine main bearing mechanism.

Although China leads the world in the amount of power generated from wind, Denmark has the highest generation rate per capita by a long way. In 2015, this small country was generating over 2 megawatt hours per person well ahead of China’s 0.26. This relatively high generation rate has resulted in a local industry which produces large numbers of wind turbines for the rest of the world. One of the fundamental requirements of ensuring reliable and efficient wind turbine operation is to keep the heavily loaded main bearings fully lubricated in all operating conditions.

Titan Enterprises were approached to supply a small flowmeter to monitor the grease being supplied into a wind turbine main bearing mechanism. For simplicity the grease mechanism is mechanically driven from the blade rotation and therefore the flow rate is potentially very low if the blades are barely rotating. This grease flow is crucial and an alarm must be tripped and the rotation stopped should the grease flow be insufficient. In addition, if the lubricant supply line became blocked the flowmeter should be able to withstand pressure that could potentially rise to several hundred Bar. An extra requirement for the required flow measurement device was for a low power system as the backup system was battery powered. Drawing upon its proven OG2 flowmeter that fulfilled the low flow measurement specifications on lubricating viscous fluids, Titan redesigned this meter to operate at 700 Bar in a small body and fitted a miniature reed switch detector to keep the power requirements to a minimum. Used in hundreds of wind turbine installations, the Titan Enterprises OG2-700 flowmeter is now a well-established monitoring device that provides valuable data helping to ensure safe and reliable operation.

For further information on the IP67 / NEMA 4 compliant OG2-700 flowmeter please visit www.flowmeters.co.uk/og2-special-700-bar-high-pressure-oval-gear-flow-meter/



STUDY 2: Metering coolant flow to industrial & medical lasers

In this case study we report on how Titan Enterprises developed a version of its 800-series turbine flowmeter to ensure consistent coolant flow to maintain the performance of a medical laser.

There are many applications of industrial and medical lasers. Whether used for cutting, welding, micro-machining, cosmetic or eye surgery - lasers generate a significant amount of heat. To ensure stable long-term laser performance, this heat needs to be quickly and effectively dissipated. Water circulated through a chiller or heat transfer system is a popular cooling method for lasers. To ensure consistent laser cooling accurate and repeatable water flow measurement is required. Working closely with a leading medical laser supplier – Titan Enterprises developed an optimised variant of its 800 Series turbine flowmeter for this application.

For further information on the 800 Series turbine flowmeter please visit click here

For further information on the IP67 / NEMA 4 compliant OG2-700 flowmeter please www.flowmeters.co.uk/og2-special-700-bar-high-pressure-oval-gear-flow-meter/

Flow Technology Spotlight

In this issue of fLowdown we look at:

Ultrasonic flowmeters – principles of operation

There are several types of ultrasonic meter technologies but as Titan Enterprises specialise in low flow using time of flight measurement this is the focus of this feature. Commercially both clamp-on and bespoke low flow flowmeters are available. These both use signals transmitted across the pipe diagonally and in the case of a clamp-on flowmeter a reflected signal. The principle of time-of-flight measurement is very simple. Using this technique injected sound travelling with the fluid flow direction will arrive sooner than flow travelling against the fluid flow. The difference is a direct function of the fluid velocity.

The transit time difference between the downstream and upstream waves is given by:

(1)

where
ΔT - is the difference in the transit times;
T12 - is the propagation from transducer 1 to transducer 2;
T21 - is the propagation from transducer 2 to transducer 1;
v - is the average axial velocity measured along the beam;
θ - is the angle between the direction of propagation and the pipe axis;
l - is the length of the path over which the integration is made and
c - is the speed of sound in the fluid.

Thus resolving the equation:

(2)

The average velocity measured along the beam is then used to compute the average velocity across the cross section of the channel and hence the flowrate of the fluid through the channel.

For smaller tube diameters there are three basic ultrasonic flowmeter configurations.


This is a similar to the example above but the path is reflected off the opposite side of the conduit to double the path length and thereby increase flowmeter resolution.



An alternative arrangement where the signal is purely axial. There is unnecessary turbulence around the change in direction which varies with flow and can upset the ultrasound transmission.




This system below uses 45° "reflectors" in the fluid path to bounce the signal from perpendicular to horizontal in line with the flow. Again the reflectors are actually in the flow so create turbulence depending upon the fluid Reynolds number.

While all these designs have advantages they also have shortfalls. As a consequence, Titan developed a patented low flow time-of-flight ultrasonic flowmeter design in which we inject the signal so that it travels purely axially without any reflections or disturbance to the fluid path (see below).

This arrangement gives very clean signals with little background noise. This improves both the accuracy and dynamic range of the meter. Because of our low frequency of operation the sound in the fluid travels as a plain wave and is fully integrated at the point the signal is received. This reduces the effects of offset velocity profiles and viscosity. There are no "bounced" or secondary signals to distort the flow calculations.

For further information on Atrato ultrasonic flowmeter technology please click here. To discuss a bespoke ultrasonic flowmeter optimised to your low flow application please contact Titan Enterprises.


How do I measure?

In this issue of fLowdown we discuss:

The Effect of Pulsating Flow on Flow Measurement Accuracy


Flow meter manufacturers calibrate their products in steady flow conditions for a very good reason. Pulsations cause big errors.

Dealing with pulsating flow has been an issue in flow measurement for over 100 years. In the 1920’s a gentleman called John Lawrence Hodgson working for George Kent Ltd identified that pulsations induced in fluid flow caused serious reading errors with differential pressure meters. He has several flow related patents and developed the Hodgson number HN which when calculated to be greater than “2” showed the error in flow would be less than 1%. It is a simple formula with just five terms:-

V. Volume of pipework between pulsation source and flow meter
f. The frequency of the pulsations
Qv. Volumetric flow rate
∂P Pressure drop between the source of the pulsations and the flow meter
P Absolute pressure at the meter.

Consequently if the flow meter is a long way from the pulsations and the line has a reasonable pressure drop the error would be reduced. This is largely still true today but modern flow meters complicate matters somewhat.

There are many types of pulsation source. The pump is a common source of pulsations particularly with smaller flows of aggressive chemicals where it is a frequent problem. How your flowmeter behaves will depend on the meter type, where it is positioned as well as the frequency and amplitude of the pulsations. A diaphragm pump can produce very severe pulsations with periods of zero flow whereas a gear pump will produce a fairly steady flow with a small "ripple" in the delivery rate. Other pump types come somewhere between these two extremes.

Turbine flow meters will generally have too much inertia to respond to velocity changes and will therefore run at something like the RMS velocity of a sinusoidal velocity profile. Positive displacement meters however will cope very well with pulsations as there is virtually no "slippage" of fluid past the measuring chamber. These flow meters will however sometimes induce pulsations of their own into the flow.

Electronic based devices have a different problem in that they have their own internal cycle times which take "slices" of flow information and report the answer. Depending where these “slices” are relative to the pulsation can cause very large reading errors due to this aliasing.

The best solution for accurately measuring pulsating flow is to remove the pulsations. This can be achieved by siting the flow meter as far away as possible from the source. This will give the pulsations time to attenuate. Increasing the pressure drop in the line will also help as long as sufficient pressure remains at the flow meter for accurate measurement. In liquid systems a hydraulic accumulator of some description with a gas bladder is very effective. If this is not possible a "tuned" column of air has been shown to work but this does need continuous monitoring for the best results. Any accumulator of this type is only likely to be effective for a given set of flow conditions and pulsation type. Also note that changing the flow rate or pump and the system will have to be re-tuned.

For further information on reducing the effect of pulsation sources in your flow measurements please click here.


Engineering Apps for Mobile Devices

An app is a software program for your mobile phone. These programs range in size and complexity from a simple flashlight application to a comprehensive navigational system for plotting positions on a marine chart. Apps allow you to customize a mobile phone or tablet to your specific set of wants and needs. They are generally easy to install, and once you start using them, will become a necessary part of your mobile life.

To save you the time and trouble of searching for and finding useful Engineering Apps we have already done this for you. Part 4 of our informative feature on Engineering Apps is detailed below.


Measurement Unit Converter

Convert Units (http://www.convertunits.com/) provides a very simple but extensive unit conversion tool with a wide variety of choices for units. To use just search in the sections given for the 2 opposing units you wish to convert and providing they measure the same parameter, the site will provide a conversion tool.

Each unit conversion you request can be saved to your favourites in your browser to allow for future fast access.


Autodesk Viewer

- easily view and share designs in your browser

Autodesk's free app allows the viewing of Autocad, Inventor, Solidworks and many other file types on your phone or tablet. This can be useful if you quickly need to show someone a draft drawing or model without having to go back to your computer. The app syncs up to the cloud allowing easy access to your files. The base app is free. The main advantages of this app are the fact that it allows instant access to models and drawings, while also allowing cloud access to your database, which also means if any changes are made while mobile, the database will not be out of sync. A360 is also availabe as a browser based application at https://a360.autodesk.com/viewer/

The android app can be found at https://play.google.com/store/apps/details?id=com.autodesk.a360


Product Focus

Entry Level Flow Indicator

Launched in 2017, the Pulsite Solo is an entry level battery powered rate and total flow indicator.

Designed as a panel or surface mounted digital instrument which requires no external power when used with magnetic sensors or contact closures, the Pulsite Solo permits customisation to suit almost any flow measurement application. With housing constructed from durable polymer, and sealed to IP64 specifications, the Pulsite Solo can be used in a wide range of operating environments. Using the 2 front panel keys and following the prompts on the LCD display the Pulsite Solo can be used with a minimum of training.

The replaceable battery life is estimated to be well in excess of 5 years when the Pulsite Solo is used as a flow totaliser. With rate readings, the life of the Pulsite Solo will depend on the duty cycle but is still several years. The Pulsite Solo can also be externally dc powered if required for example when used with an electronic sensor such as a Hall effect device. This affordable flow indicator will take frequencies from dc through to 2 KHz and scale them to display rate or total. The scaling factors are adjustable from 0.01 to 9999 and the time base is selectable as seconds, minutes or hours.

For further information on the Pulsite Solo flow indicator please click here.


Bulletin Board

Titan Enterprises appoint new Development Engineer

We would like to welcome Neil Hannay as our latest Development Engineer at Titan Enterprises. Neil has been in the industrial commercial development sector for over 25 years and brings a wealth of application and project management expertise to Titan. With specific skills in innovation process management, Neil is looking forward to helping ensure Titan continues to develop new flow measurement solutions to ensure their customers are the most competitive.

Humour

At the start of a new year here are a few bits of humour that we hope will make you smile.


Q: What do you call two crows on a branch? - A: Attempted murder


Q: What do you get when you put root beer in a square glass? - A: Beer


Engineer In Hell
An engineer dies and reports to the pearly gates. St. Peter checks his dossier and says, "Ah, you're an engineer - you're in the wrong place." So the engineer reports to the gates of hell and is let in. Pretty soon, the engineer gets dissatisfied with the level of comfort in hell, and starts designing and building improvements. After a while, they've got air conditioning, flush toilets, and escalators, which makes the engineer a pretty popular guy. One day God calls Satan up on the telephone and says with a sneer, "So, how's it going down there in hell?” Satan replies, "Hey, things are going great. We’ve got air conditioning and flush toilets and escalators, and there's no telling what this engineer is going to come up with next." God replies, "What??? You’ve got an engineer? That’s a mistake - he should never have gotten down there; send him up here." Satan says, "No way. I like having an engineer on the staff, and I'm keeping him." God says, "Send him back up here or I'll sue." Satan laughs uproariously and answers, "Yeah, right. And just where are YOU going to get a lawyer?" .

Click here for a printable version of Flowdown.

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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