Transcript Technology Review – Level Measurement of Bulk Solids and

• Think of a number between 1 and 10.
• Multiply that number by 9.
• Take the digits in that number and add them together.
• Subtract 5 from that number.
• Using the formula A = 1, B= 2 etc., convert that number to a letter.
• Identify the English name of a European country that begins with that letter.
• Take the last letter of that country’s name and think of a mammal whose
name begins with that letter.
• Finally, using the last letter of that mammal’s name, choose the name of a
fruit.
Recent Directions In Bulk Solids
Level Measurement & Monitoring
• Self-Validating sensors eliminate overfilling
• Successfully implement continuous level
Level Measurement
– Continuous v. intermittent
– Six primary technologies
– Contact / non-contact
– Sensor location
– Converting to weight
– How do we ensure success?
Guided-wave radar in use measuring seed corn at Syngenta plant
Level Monitoring
– Presence / absence
– Five primary technologies
– Contact v. non-contact
– Low or high level
– What if they fail?
RF capacitance sensor in use monitoring high level condition in flyash silo
at Buzzi Unicem cement plant.
When Level Monitors Fail:
The Cost of Overfilling Your Bin/Silo
$5K estimate (concrete producer) …...
– lost material
– clean-up costs
– fines due to air quality issues
– damaged bags, baghouse, vents
– lost production
Top Ten Ways You Know You Have
Overfilled A Silo
#10: Pneumatic tubing is cascading to the ground as the pressure
blows the fill lines off the silo
#9:
The bag house on top of the silo is no longer visible, as it’s now
covered by the material that was in your silo
#8:
The “creaking” sound you hear is coming from the roof of the
building next to the silo as material spills onto it
#7:
The truck driver filling the silo suddenly looks very sheepish as he
prepares to “make like a Baptist Church and split”
#6:
Flocks of pigeons suddenly get airborne
Top Ten Ways You Know You Have
Overfilled A Silo
#5:
It sounds like it’s hailing outside while the sun is out
#4:
There is a loud clanking sound as the silo railing hits the
pavement
#3:
A Sherpa asks if you need a guide to climb the mountain of
material now piled next to the silo
#2:
Your maintenance manager is in a panic because he can’t find a
shovel
And the #1 Way You Know You Have
Overfilled A Silo
All of your employees are
scrambling to move their cars!
Preventing Silo Overfill
The Number One Solution ?
– Self-Validating Level Monitors
– Not new concept
– More than simple “fail-safe”
– Sensor determines self-health
– Sensor outputs provide assurance
– Characteristics of a self-validating point level monitor
– Continuous diagnostic of critical internal functions
– Independent “level” and “health” status outputs
– Premium price
Today’s Self-Validating Technology
for Bulk Solids
– Most universal bulk solids technology
– Lowest cost technology
– Multiple vendors
– Self-Validating technologies
– Optical
– Hall-effect
– “Fail-Safe” PLUS
– Premium justified by ROI
Most Popular Continuous Level
Measurement Device?
– Guided Wave Radar
– Usage increasing at nearly 21% per year (Venture Development Corporation)
– Should be strongly considered for bulk solids
– Broad application base in bulk solids
– High reliability with no moving parts
– Affordable
– Easy to install
– Multiple vendors
– How do we ensure successful installations?
Ensuring Successful Use of
Guided Wave Radar
– How does it work?
– TDR (time domain reflectometry)
– Energy focused down wave guide
– Time-of-flight related to distance / level
– Direct and TBF (tank bottom following) modes
– Direct preferred
– TBF can provide solution for low dielectric materials
48’ full vessel
Er = 1.7
PVC compound
TBF Mode used
Material level
End of counterweight
Measuring PVC compound at Er = 1.7 at plastic pipe manufacturer
Ensuring Successful Use of
Guided Wave Radar
– TECH TIP: Accurate measure of Er (dielectric constant) of material
– Measuring range is directly related to Er:
– “rule of thumb”: the % of radar energy actually reflected by the material
surface is the dielectric constant value, i.e. Er = 2.0 means  2% of
energy is reflected
Material
Almonds (shelled)
Asphalt, Liquid
Baking Soda
Coffee Beans
Calcium Carbonate
Carbon Black, Powder
Cement Powder
Clinker
Corn, Whole
Diesel Fuel
Ethanol
Flour, Wheat
Fly Ash
HDPE
Lime, Quicklime
Milk Powder
Nylon
Paraffin Wax
Polystyrene, Expanded
Beads
Potash
PVC
εr Dielectric Constant
Typical Range (m/ft)
9.0
2.5
5.7
1.9
9.1
1.4-6.0
1.5-2.5
2.7
5.0
1.8
24.3
5.0
1.9-2.6
1.6
4.8
1.7
4.0
2.1
2.2
30+/100+
30+/100+
30+/100+
12/40
30+/100+
0-30+/0-100+
0-30+/0-100+
30+/100+
30+/100+
12/40
30+/100+
30+/100+
12-30+/40-100+
6/20
30+/100+
10/33
30+/100+
30+/100+
30+/100+
5.6
1.8
30+/100+
12/40
Table 2: Examples of material dielectric constants and measuring range.
Does not include measuring capability using TBF method. Results can
vary from brand to brand.
Ensuring Successful Use of
Guided Wave Radar
– TECH TIP: Respect the signal field around wave guide
– Problems:
– Parasitic signal reflections
– Signal degradation
– Solutions:
– Proper sensor location
– Proper installation
Nozzle effect
Plastic Pellet
Er ~ 1.7
Range ~ 20 ft.
Parasitic reflections affect measurement range and ability.
Ensuring Successful Use of
Guided Wave Radar
– TECH TIP: Respect the signal field
around wave guide
– Most common problem:
– Using inappropriate nozzle
– Half-coupling preferred
– H must be < D if nozzle used
– NEVER extend nozzle in silo
Ensuring Successful Use of
Guided Wave Radar
– TECH TIP: Respect the signal field around wave guide
– 2nd most common problem:
– Sensor location allows probe to contact obstructions or silo wall
– Best location between 1/6 to 1/4 of diameter in from silo wall
– Take angle of repose into account
– 3rd possible problem:
– Probe too long
Ensuring Successful Use of
Guided Wave Radar
– TECH TIP: Respect the signal
field around wave guide
Installation
not optimized
Instructions
not followed
Ensuring Successful Use of
Guided Wave Radar
– TECH TIP: Respect the signal
field around wave guide
Installation
optimized
Instructions
followed
Feed Pellet
Er ~ 1.85
Probe too long, touching cone. No end-of-probe reflection.
Summary: Ensuring Successful Use of
Guided Wave Radar
– Guided Wave Radar is reliable and accurate
– Proper application considerations:
• Dielectric constant
• Measuring range
• Sensor mounting location (consider angle of repose)
– Proper installation considerations:
• Eliminate nozzles if possible; follow D > H rule
• Sensor mounting location & material flow (probe must not contact silo)
• Proper probe length (especially for low dielectric applications)
Summary: Self-Validating Level
Monitors
– Unknown Level Monitor Failure Can Lead to Overfilling Silos and Bins
–Overfilling can cost you big time
– material loss, cleanup, damage, fines, lost time, lost production
–Self-validating level monitor is not just a simple fail-safe device
– detects BOTH level monitor health and material presence/absence
– beyond fail-safe (not just power failure)
– The cost of a self-validating level monitor? About $300.
– The value of preventing silo overfilling? Priceless!
Trivia Questions
– Name the game that originated in India that features a board with “Home” in the
center and a “Start” in each corner.
– Cricket
– What English sports car was made world famous in the 3rd 007 James Bond
movie?
– Aston Martin with license plate BMT 216A
– What was the greatest number of home runs hit by Henry Aaron in one season?
– 47 in 1971
– In 1920 what hockey team set the all-time record of most goals (16) in a single
game?
– Montreal Canadiens March 3, 1920 16-3 against the Quebec Bulldogs
– Who was Baseball’s “Say Hey” kid?
– Willie Mays
Trivia Questions
– What was the Texans win-loss record at the end of regular season play in the
NFL 2006/2007 season?
– Wins = 6
– Losses 10
– Where did Clyde Drexler go to coach basketball after retiring from the Rockets?
– University of Houston
– What was Sam Houston’s middle name?
– He didn’t have a middle name