How to Select Level Sensors Image Credit: ABB Measurement Products | Honeywell | Campbell Scientific   Level sensors are used to detect liquid or powder levels, or interfaces between liquids. They are an important part of a fluid system because the position and displacement of an object or media is critical to know in many applications. The substance to be measured could be inside a container or in its natural form such as a lake or river. A sensor is able to detect a change...
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Q & A on Level Sensors

We asked our users for their input on Level Sensors. Here are the results of 80 users familiar with Level Sensors.

Who Took Our Poll? | Design Trends | Applications and Use | Features | Buying Advice

Who Took Our Poll?Top

Design TrendsTop

Q:
What new technologies are influencing level sensor design?
15 answers
Answers:
Not aware of any really "new" technologies. For my purposes, the ultrasonics and lasers are the most practical and usually offer the best value in terms of price/performance.
~Engineering, Process/Production, Abbeville, SC
Anything more reliable, more durable, for less cost as the technology being replaced.
~Design Engineer, Beatrice, NE
Current flow types are most common, but with high precision radar type are use.
~Technical Support/Services, Miri, Malaysia
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Q:
From your perspective, which companies are creating the most innovative level sensors?
12 answers
Answers:
There are way too many, and since my study/purchasing is not my primary function, but only incidental to what I do, I really couldn't say.
~Engineering, Process/Production, Abbeville, SC
Good question; hard to say, being so many good players out there.
~Mike M, Marketing/Sales, Kenmore, WA
Instrumentation Services ( ITS) South Africa.
~Kgosietsile kgosi P, Technical Support, Lobatse, Botswana
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Applications and UseTop

Q:
What are some of the applications you have used level sensors for?
18 answers
Answers:
We have a number of applications: - Liquid level in a tank: radar - Single and multiple point liquid detection as overspill protection: conductivity / electrodes - Foam detection: conductivity - Absolute liquid level where there is foam on top that is not of interest in a pressurized tank: pressure sensors for the determination of density and pressure in overhead for calculation of liquid level
~Patricia T, Process Engineer, Amsterdam, Netherlands
Tank monitoring at Van Den Burgh and Jurgens (hydrostatic), Radar level measurement PF storage bins, Reservoir level monitoring mKomati River Scheme (hydrostatic), sludge level monitoring in settlers at gold mines (ultrasonic), and many more.
~Peter Tranter, Engineering Consultant, Noordwyk / Midrand, South Africa
On bulk liquid storage tanks - to indicate amount in tank. For run tanks in continuous processes, to turn on/off refill pump. As indicators in various containers, to trigger alarm for overfilling/almost empty.
~Engineering, Process/Production, Abbeville, SC
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Q:
Please share with us any “non-standard” applications that level sensors have been used for.
4 answers
Answers:
Sludge blanket level measurement - tricky one as "through-liquid" ultrasonic methods must be used so as not to interfere with submerged rakes etc.
~Peter Tranter, Engineering Consultant, Noordwyk / Midrand, South Africa
Anaerobic digestion with a wide range of waste streams.
~Patricia T, Process Engineer, Amsterdam, Netherlands
Bent probe guided wave radar for awkward installations.
~Paul Wragg, Marketing/Sales, Newbury, UK

Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of level sensors?
6 answers
Answers:
When E+H first launched their range of Ultrasonic level devices (+/- 1981) we supplied a number of tanks at a fertilizer company - only to find that within a few months the Stainless Steel diaphragms had disappeared into the tanks. The fumes from the liquids (Sulfuric acid storage tanks) had dissolved the glue holding the diaphragms in place thus causing them to fall into the tanks leaving the ultrasonic crystals etc open to further attack by the fumes.
~Peter Tranter, Engineering Consultant, Noordwyk / Midrand, South Africa
Sometimes they should know the way they are going to do their installation, whether vertical or horizontal, so that they can be calibrated for the right usage.
~Kgosietsile kgosi P, Technical Support, Lobatse, Botswana
Never apply voltage across the sensor output terminals. The resistive coil burns ( as it acts as a heater )
~VIJAY D, Research & Development, PUNE, INDIA

FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
11 answers
Answers:
The market seems to be responding pretty nicely with wish list features, capabilities, including prices coming down.
~Mike M, Marketing/Sales, Kenmore, WA
Able to be tailored to our output requirements, able to function reliably in mobile equipment, at a low cost.
~Design Engineer, Beatrice, NE
Try to reduce the product from losing calibration or adding some devices for calibration loss sensor.
~Kgosietsile kgosi P, Technical Support, Lobatse, Botswana
Ease of access to technical bulletins when deciding on best method for level measurement.
~Peter Tranter, Engineering Consultant, Noordwyk / Midrand, South Africa
Higher positioning accuracies at the lowest possible cost.
~VIJAY D, Research & Development, PUNE, INDIA
Non contact, differentiation of media according to density.
~Patricia T, Process Engineer, Amsterdam, Netherlands
Precise, fast response, bio-fuel resistance and low cost
~Kakuda-city, Japan
Integral temperature, modbus output,
~Paul Wragg, Marketing/Sales, Newbury, UK
2 wire sensor Immersible in fuel
~Marketing/Sales, Cork, Ireland
Local Display Easy Configurable
~H R Gautam G, Design Engineer, Noida, India
Reliability
~Mark A, General Management, Adelaide, Australia

Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of level sensors?
6 answers
Answers:
Don't listen to manufacturers' reps who claim to know every thing - they may know something about their product but not much on applications - they simply tend to be "encyclopedia" sales men.
~Peter Tranter, Engineering Consultant, Noordwyk / Midrand, South Africa
Ultrasonic and radiation often provide false readings due to the nature of the foam and the debris floating. The pressure sensors often work best.
~Patricia T, Process Engineer, Amsterdam, Netherlands
The effective tank height is critical to be specified to get the correct level sensor.
~VIJAY D, Research & Development, PUNE, INDIA
They should be quite sure of their application.
~Kgosietsile kgosi P, Technical Support, Lobatse, Botswana
Consult experts, such as Magnetrol UK
~Paul Wragg, Marketing/Sales, Newbury, UK
Check weights
~Mark A, General Management, Adelaide, Australia

Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using level sensors?
8 answers
Answers:
Use Sam's fuel level sensor which gives resistive output and has in built two switches and also has a mechanical indication. -- low cost
~VIJAY D, Research & Development, PUNE, INDIA
Speak to the manufacturer's technical expert or utilize an independent with years of experience in most industries and applications.
~Peter Tranter, Engineering Consultant, Noordwyk / Midrand, South Africa
Conductive is ok if placed vertical and a stream of clean water is available.
~Patricia T, Process Engineer, Amsterdam, Netherlands
I think pressure based level sensors are much better that ultra sonic ones.
~Kgosietsile kgosi P, Technical Support, Lobatse, Botswana
Check accuracy, contact rating and no. of contacts.
~H R Gautam G, Design Engineer, Noida, India
Consult experts, such as Magnetrol.
~Paul Wragg, Marketing/Sales, Newbury, UK
Check specs match information
~Mark A, General Management, Adelaide, Australia
TEST, TEST, TEST
~Design Engineer, Beatrice, NE


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