How to Select Liquid Level Sensors Image Credit: ABB Measurement Products | Baluff, Inc. | Clark Solutions | Gentech International Ltd.   Liquid level sensors are used to detect liquid levels or interfaces between liquids such as oil and water or liquids and solids. They can be defined as sensors or transducers, or as integrated systems with instrumentation and control capabilities.   Types of Sensors Liquid level sensors provide measurement of the height or position of a...
Learn More about Liquid Level Sensors


Q & A on Liquid Level Sensors

We asked our users for their input on Liquid Level Sensors. Here are the results of 140 users familiar with Liquid 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 liquid level sensor design?
22 answers
Answers:
Modified and improved technologies like float, capacitive, ultra-sonic, hot wire, pressure and radar have reached their limits and the limits of the operating conditions under which they can measure liquid level. Furthermore, the sensors created by those technologies can measure only liquid level and can not simultaneously measure other parameter of the liquid such as temperature.
~Josef M, Research & Development, Los Angeles, CA
Depends on the market. Absolute sensing is necessary for hostile environment and therefore chip design that can provide continuous, linear precision on the total scale of the measure is key.
~Rpbert F, Consultant, Blauzac, France
Technologies that allow the measurement to be product independent, i.e nucleonic, RADAR (microwave), laser, load cells,
~Tony S, Marketing/Sales, Sydney, Australia
See More Answers
Q:
From your perspective, which companies are creating the most innovative liquid level sensors?
19 answers
Answers:
Siemens, SST
~General Corporate Mgmt, Christchurch, New Zealand
Endress+Hauser, Saab, Magnetrol
~Marketing/Sales, Dartmouth, Canada
Endress+hauser Emerson and Honeywell
~Marketing/Sales, Nigeria
See More Answers

Applications and UseTop

Q:
What are some of the applications you have used a liquid level sensor for?
34 answers
Answers:
Sewage pumping station Wet Well level; Aerator tanks; Chemical dosing tanks - Alum, Sodium Hypo, Ferric Chloride, Sodium Bisulphite and HCl; Channel Inlet (flow); Step Screen (differential); Digester Level; Scum Tank Level; Thickened and non-thickened sludge level; Centrate Tank level; Chemical Storage tank Level; Diesel Tank; ULP Tank, Reservoir Water: Rainwater harvesting tank.
~Tony S, Marketing/Sales, Sydney, Australia
1. In chemical industries where liquid storage tanks should be automatically controlling the liquid levels and its pump operations. 2. For underground waste water storage sumps operation. 3. Hydraulic storage tanks
~Nilesh S, Manufacturer, Baroda, India
Oil, fuel and coolant level in cars and trucks. Sensing level of foamy oil in refrigeration compressors, washing machines, washed-food disposable tanks. Level of two liquids such as oil and water or fuel and water.
~Josef M, Research & Development, Los Angeles, CA
See More Answers
Q:
Please share with us any “non-standard” applications that a liquid level sensor has been used for.
15 answers
Answers:
RADAR level transmitter used to determine batch level (50mm) of Molten Glass @ 1000 degrees Celsius, being used concurrently and to compare with a custom made (albeit crudely) water cooled float attached to a hydraulic ram. The float was more repeatable but suffered from lag in to the batch level.
~Tony S, Marketing/Sales, Sydney, Australia
Mobile diesel measurement and tracking. That is application were diesel being delivered to remote locations are tracked to avoid theft on transit. Tankers are segmented and can carry up to 33000 liters of liquid. I need to monitor this 33000 liters of fuel on transit.
~Emmanuel I, Engineering Consultant, Lagos, Nigeria
The same electronics and a slightly modified probe of a liquid level sensor was used to detect ice on a surface and measure acidity of liquid.
~Josef M, Research & Development, Los Angeles, CA
See More Answers
Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of a liquid level sensor?
10 answers
Answers:
One model we wanted to use was not fast enough to compute accurately a fast rising liquid level (1 meter per minute). The sensor would at one point lose its echo and fall in its default state. Unfortunately, in our case, getting in that state would start some pump and most of the times would infiltrate air in the pumping system. This would mean that the system needed to be flushed and that is a big loss of time and performance.
~Sylvain Larocque, Engineer, Hawkesbury, Canada
Yes. A Guided RADAR sensor (aka TDR or Guided Microwave) was specified for a grain silo that is 9m high. The sensor has a 10m cable and is mounted into the silo from the top and fixed to the lid (roof is only made of mild steel). As cable is too long it gets jammed when a knife valve closes and pulls down roof of silo.
~Tony S, Marketing/Sales, Sydney, Australia
Incorrect sealing of diaphragms on ultrasonic level measurement on sulphuric acid storage tanks caused the diaphragms to drop into the liquid leaving the rest of the sensor unprotected against the acid fumes.
~Peter T, Owner of an Instrument supply company - often used to specify/consult on applications in the measure, Midrand, South Africa
See More Answers

FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
17 answers
Answers:
My design can be used to either passively or actively measure and control liquid level and temperature at multi-points using a single ( one location) low-cost microprocessor-based electronic hardware and firmware.
~Josef M, Research & Development, Los Angeles, CA
Non-contact, Non-intrusive, Easy to set-up, No moving parts, long term stability, easy to exchange (electronics or hardware), easy to upgrade (firmware), easy to communicate with locally and remotely
~Tony S, Marketing/Sales, Sydney, Australia
Plug and Play radar or ultrasonic transmitter for long range , high temperature applications in a dusty environment
~Ricardo Rojas, Engineer, Vancouver, Canada
See More Answers
Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of a liquid level sensor?
12 answers
Answers:
1) Maximize the use and adaptability of the liquid sensor by using a low-cost micro-controllers with firmware to measure liquid level at multi-points and measuring a range of heights. 2) Eliminate calibration cost by using a self-calibrated technology which uses low-cost digital electronics with firmware. 3) Select a single technology that can measure liquid level and other liquid parameters such as temperature. 4) Minimize maintenance cost by using a technology that has a firmware-based health-monitoring system. 5) For feedback systems to control liquid level, select a sensor that can control the level measurement and the controller (i.e. valve, pump , motor).
~Josef M, Research & Development, Los Angeles, CA
Look at every aspect of the application as mentioned previously, but probably the two biggest mistakes are not specifying correct process connection and not mounting in correct position.
~Tony S, Marketing/Sales, Sydney, Australia
Talk to a supplier with the most complete variety of level instruments to get best advice on the right type to use for your application.
~Amir Hedayatnia, Marketing/Sales, Strongsville, OH
See More Answers

Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using liquid level sensors?
11 answers
Answers:
1) Use a firmware-based adaptable sensor that can measure multi-properties of the liquid at multi-points such as level and temperature, height, varying environment using the same technology. In the computer business, multi-media technology was developed which uses the same hardware and different software to replace, individual answering machine, fax machine, stereo, video etc. The cost-effective future of liquid properties sensing is the development of a single technology that can measure most of the liquid parameters such as level, temperature, acidity, viscosity, flow, pressure, and liquid particle constituents. 2) Use self-calibrated technology that can measure accurately level and/or temperature. 3) In feedback systems for controlling level and temperature, develop a sensor with firmware that can be used together with active control like valves, pumps and motors. In some present feedback systems, the controller is sold by one company and the liquid level is sold by another company and when the system does not work, the sensor suppliers blames the controller suppliers and vice versa. Having a firmware based liquid level sensor that can be used with adjustable gains will avoid these problems. 4) Develop firmware that will monitor the health of the liquid level sensor or the entire feedback system.
~Josef M, Research & Development, Los Angeles, CA
Look for global battery life with reliable calculation methodology and precise scenario. Look for suppliers who have proven they can provide a global solution for all your requests
~Rpbert F, Consultant, Blauzac, France
Make sure the measurement technology matches the application - don't use exotic forms of level measurement when a simpler/sounder method is available.
~Peter T, Owner of an Instrument supply company - often used to specify/consult on applications in the measure, Midrand, South Africa
Testing the product in a replica of the real application is crucial to obtain the expected results. Especially in a large application since many factors can influence the actual results.
~Sylvain Larocque, Engineer, Hawkesbury, Canada
Talk to a supplier with the most complete variety of level instruments to get best advice on the right type to use for your application.
~Amir Hedayatnia, Marketing/Sales, Strongsville, OH
Look at overall cost compared with time taken to mount, connect, set-up and operate. Determine best method for the application.
~Tony S, Marketing/Sales, Sydney, Australia
Be careful check the specif. and if the vendor has application know how as opposed to sales training.
~Alan N, Engineering Consultant, Sydney, Australia
The position of the sensor is critical to good performance.
~Ricardo Rojas, Engineer, Vancouver, Canada
Yes. I recommend level sensor which is no moving parts.
~Shinichiro Sakata, Marketing/Sales, Tokyo, Japana
Specification should meet with the application.
~Dadang R, Engineer, Tangerang, Indonesia
Use the long life battery.
~Redwan R, Technical Support, Riyadh, Saudi Arabia


Related eNewsletters
See More

Also on GlobalSpec...
  • Receive email updates on new products and suppliers of interest to you
  • Online, interactive conferences / trade shows featuring latest news and industry trends
  • CR4
    Q&A and discussion for the engineering, scientific, and technical community
  • Engineering and scientific news from hundreds of sources
  • Industrial manufacturers and distributors