Process Level Transmitters

Hi all.

I have a little project that I am looking at starting and I am hoping for some advice on level transmitters. The application will be inventory control of bulk flour. We are looking at different options, but mainly want to continually monitor the level of the silo at all times. Ideally I would like to connect to a plc and monitor the level and possibly export the data to an excel file. also would like to utilize a high level function to prevent over filling the silos when we receive flour. Is there anyone that has used radar or sonar in these applications? if so what have you had the best success with in these applications?

Travis

Level Sensor for Flour application

AGENTTINFOIL said:

Hi all.

I have a little project that I am looking at starting and I am hoping for some advice on level transmitters. The application will be inventory control of bulk flour. We are looking at different options, but mainly want to continually monitor the level of the silo at all times. Ideally I would like to connect to a plc and monitor the level and possibly export the data to an excel file. also would like to utilize a high level function to prevent over filling the silos when we receive flour. Is there anyone that has used radar or sonar in these applications? if so what have you had the best success with in these applications?

Travis

Click to expand...

In my experience don't use radar or sonar, you will have a hard time on this type of sensors. Use Endress & Hauser type sensor which if my memory serve me corect is nivocompact type level sensors, Solicap M FTI55 or Solicap M FTI56.

http://www.us.endress.com/

One more thing configure your logic in the PLC as a fail safemode, so as to your level sensors.


Regards

Sherwin

Maj. Toxido said:

In my experience don't use radar or sonar, you will have a hard time on this type of sensors. Use Endress & Hauser type sensor which if my memory serve me corect is nivocompact type level sensors, Solicap M FTI55 or Solicap M FTI56.

http://www.us.endress.com/

One more thing configure your logic in the PLC as a fail safemode, so as to your level sensors.


Regards

Sherwin

Click to expand...

Solicap's only provide level detection, not continuous as required for soli inventory.

I have seen almost all kinds of sensors used for application such as silo inventory, with most failing. I agree, that radar and and sonar provide the most grief, and capacitance type probed cause issue just be the shear length a probe must be to allow level detection in silo 100 feet high.

I have heard of, but not seen, a probe that unwinds a cable until that cable comes into contact with the product in the silo. The number of pulses counted as this cable unwinds is used to determine the top of the product in the silo, and using some simple math, the product amount in the silo can be determined.

Do a google on Silo Level cable reels

curlyandshemp said:

...a probe that unwinds a cable until that cable comes into contact with the product in the silo. The number of pulses counted as this cable unwinds is used to determine the top of the product in the silo, and using some simple math, the product amount in the silo can be determined.

Click to expand...

We have used those. While they work, they are a constant maintenance issue. You know how a fishing reel gets backlash......

I have two 32' tall lime silos at a water treatment plant that have been monitored for 15+ yrs. with a Milltronics/Siemens Sitrans (ultrasonic) with no issues. I have heard of issues with this type of technology when used with fine grain solids but I have personally not had any (with Lime). The controller has 4-20 out and relays for hardware based alarms. It is pricey , the two channel model was about $2K.


RWW

We switched from the yo-yo probe here to Endress Guided Wave Radar probes for three extreme high dust content silo's, and don't have any troubles.
The transmitters are mounted outside in full weather, no problems.

I completed a project this year to monitor liquid levels of seven bulk storage tanks and decided to go with Hawk Measurement Sultan series acoustic wave technology. These sensors are great in that they electronically compensate for dust or mist by increasing the gain of the acoustic signal. I have found them to be very accurate and easy to use. The price was very reasonable, but the compensation technology sold me on the sensors.

Here is the Hawk website. http://www.hawk.com.au/

Best regards

BANNER Engineering QT50U

Take a look at QT50U from BANNER for level sensing in your application.

Here is the website:
http://www.bannerengineering.com/en-US/products/industry/17/660/Food-Beverage/101/U-GAGE-QT50U-Series

The secret with guided radar (E&H) is to set the unit up correctly in the first place. For solids you should make sure the Medium Properties are correct (The Dielectric constant for flour seems to be about 2.4). Once you have the unit working use the envelope curve to check that the tank mapping is suitable. Endress and Hauser provide good manuals which explain all of this but most of the problem installations I see are a result of just fitting the probe and expecting it to work out of the box.(also applies to ultrasonics)

Andybr

Andybr said:

The secret with guided radar (E&H) is to set the unit up correctly in the first place. For solids you should make sure the Medium Properties are correct (The Dielectric constant for flour seems to be about 2.4). Once you have the unit working use the envelope curve to check that the tank mapping is suitable. Endress and Hauser provide good manuals which explain all of this but most of the problem installations I see are a result of just fitting the probe and expecting it to work out of the box.(also applies to ultrasonics)

Andybr

Click to expand...

True that, but E&H is nice about that. For one, being lazy, I sent them all the information about materials and silo height, and they pre-set everything nearly perfectly. Then, they have a very reasonable start-up service (yes, it costs money, but well worth it) which not only extends the warranty on the device(s) but also comes with a full 100% guaranteed refund if it turns out the device isn't suitable for the application.

I've got 4 of the guided radar probes here now, on wildly different materials, conductive, non conductive, hot molten wax, extreme fine dust, 12 foot to 96 foot probe, and have had no problems with any so far (knock on wood).