TSCO-THERMO FISHER

Thermo Scientific
Bulk Weighing & Monitoring
Belt Scale Systems

2
PRICE
Standard
Professional
Basic
10-101-R
10-17
10-20
10 - 14
Certifiable models
Standard Products
Common
Electronics
Architecture
Market leaders with excellent brand name recognition
Belt Conveyor Scales
P
E
R
F
O
R
M
A
N
C
E

3
What is a Belt Conveyor Scale?
• A device to provide a rate of
flow of bulk material passing a
defined point on a moving
conveyor
• Rate of flow, measured against
time is integrated into total
weight
TOTAL
RATE
REMOTE
TOTAL
REMOTE
RATE
LBS/FOOT
EXCITATION
FEET
TRAVELED
FT / MIN
TOTAL =
RATE =
FOOT
LBS
X FEET TRAVELED
FOOT
LBS
X
MIN
FT
A00759

4
How is a belt conveyor scale different from a static scale?
• Static scales record the weight of a DEAD LOAD
• Definition: DEAD LOAD A non-varying or static load (weight)
• Belt conveyor scales record the weight of a LIVE LOAD
• Definition: LIVE LOAD A moving load or a load of variable forces that act
upon a structure in addition to the load weight

5
Live Load Weighing:
• Conveyor belt scales need to react to constantly
changing vertical, horizontal and vector forces.
• These forces need to be controlled and monitored

6
What do Belt
Conveyor Scales do?
Measure weight of
material passing a fixed
point
Use speed sensing to
determine distance
traveled
Weight X Distance X
time = Wt per period

7
Thermo Scientific – Ramsey Belt Scales Position in the Market
• Tens of thousands sold by Ramsey, Thermo Ramsey, Thermo Scientific
• At a rate of about 1200 a year
• We are the # 1 supplier of belt scales in the world

8
Where are they used?
• Continuous, automatic processes where batch loading delays are
undesirable.
• Inventory Control
• Material blending
• Fee or custody transfer of bulk materials

9
Which Scale to sell?
• Application generally determines accuracy requirement
• Process monitoring ±1/2 to ±5%
• Crusher feed
• Stockpiling (aggregates)
• Flow rate monitoring (sampling efficiency)
• Process Management ±1/4 to ±1%
• Production rate monitoring
• Blending systems
• Stock piling
• Truck load-outs
• Fee or Custody transfer ±1/8 to ±1/4%
• Government requirements
• Rail, truck or barge load-outs
• “As-fired” coal handling
• Inventory control systems

10
What scale to offer?
• Five basic scale designs are available
• Several different integrator models and configurations are available
• A variety of speed sensors are available.
• The following will define the purpose of these differences and how they can
best be applied as a solution to a weighing need.

11
Belt Conveyor Scale Components:
• Electro-Mechanical or “Electronic” scales have four major components, each
with particular characteristics that define the accuracy capability of the system.
• Weighbridge
• Load Sensor
• Totalizer / Integrator
• Speed Sensor

12
Load Sensor
• The load sensor is a device that converts a weight or load into a
proportional electrical signal - transducer
• Load cell or strain gauge
• Older designs used a linear voltage differential transformer (LVDT)

13
Totalizer / Integrator:
• The integrator is the brain of the system
• Accepts load cell and speed sensor signals
• Integrates load over time to produce flow rates and accumulated totals
• Provides outputs for process control
MT9000 Electronics

14
Speed Sensor:
• The speed sensor monitors belt travel and transmits a signal
proportional to true belt speed

15
Load Sensor (load cell):
• Electro-Mechanical device, generally stainless steel or nickel plated
carbon steel
• Strain gauge imbedded internally, produces an electrical output
proportional to load
• Converts force to an electrical signal
• Must have minimum deflection
• Needs to be stable over temperature and barometric changes
• Must be sealed from the environment
• Must be repeatable and linear
• Approval by OIML or NTEP confirms these requirements

16
Integrator:
• Considerations included in the design of a belt scale integrator
include:
• temperature stability
• capabilities for both positive and negative integration
• ability to display in various engineering units
• provide back up or protection for memory
• provide a means of sealing or protecting metrological settings
• provide ease of operator access for routine calibrations

17
Speed Sensor
• The speed sensing is actually the result of two devices, the travel
sensor and the signal generator
• Travel sensor is typically a large diameter pulley, tail pulley or
snubbing roll
• adequate wrap angle to prevent belt slippage
• positive contact to ensure rotation at true belt speed
• Signal generator must be linear for consistent speed representation
• Provide a signal compatible with integrator input
• Operational over a large speed range

18
Belt Scale Limitations:
MOST errors in belt conveyor scales are caused by mechanical factors!
Erroneous measurement of belt travel and material mass are usually caused
by idler contamination and belt pre-tension in combination with idler
misalignment.
The conveyor structure, conveyor belt, loading practices and maintenance are
as important for accurate weighing as the scale itself!
Correct calibration (accuracy) only lasts as long as the post calibration
geometry of an installation’s components remain unchanged!

19
Accuracy:
Items that contribute to the accuracy or inaccuracy of a belt conveyor
scale include:
• the scale frame design
• the conveyor structure and profile
• the idler frame and condition of the rolls
• the conveyor belt and belt tension
• speed sensing roll
• the proper use of belt scrapers
• material feed method
• condition and design of belt tensioning device (take-up)

20
The Conveyor Belt:
Conveyors can be designed to transport material, and some, but not all of
these can become weighing conveyors. Conveyors designed for
weighing will transport material.
A main concern is the belt itself.
• Does it support the load or transfer the load to the idlers?
• Does it conform to the idler trough angle?
• Is it uniform in construction?
• Are splices smooth, or cause the belt to jump as it crosses the idlers?
• Does it track evenly from tail pulley to head pulley?
• Does it retain moisture, or does material adhere to its surface?

21
Scale Location:
The location of the belt conveyor scale is critical to its success.
Following are recommendations for scale locations. For high accuracy
applications, these are requirements.
Cheating on these items will reduce the accuracy capability of the scale
system.

22
Minimum 20’ (5 idler spaces) from load point and end of skirts.
Tension

23
The conveyor loading mechanism shall be designed to provide uniform belt
loading.
Uniformity of Belt Loading and Flow

24
Single load point provides more consistent belt tensions.
Load Point

25
Incline angle shall be such that slippage of material along the belt does not
occur.
Material Slippage

26
Minimum 20’ (5 idler spaces) from tangent point of convex curve.
Convex Curves

27
Concave Curves
Minimum 40’ from point of tangency.

28
Tripper Conveyors
Minimum 40’ from tripper position when fully retracted.
Not acceptable on certifiable applications, per Handbook 44.

29
Scale/Weigh Idlers
20 FT
20 FT
Enclosed or Protected
Area
Protection from Environmental Factors

30
Conveyor Support
Deflection between two adjacent idlers must be less than 0.025” (0.6 mm) under
load. No conveyor expansion joints or splices should be located in the region of the
scale.

31
Cable Conveyors
Cable or Rope conveyors are not suitable for conveyor belt scales.

32
Stacking Conveyors
Avoid stacking conveyors that change the angle of elevation and/or traverse.

33
Take-Up Types

34
NO
YES
NO
A00252
Belt Construction and Tracking
Conveyor belt must track centrally on idlers and contact all rollers.

35
Idler Type
Offset type idlers should not be used on pivoted type scale carriages.

36
Idler Troughing Angle
Troughing angles of 35 degrees or less, are preferred.

37
Training Idlers
Training idlers must be more than 60’ from the weigh idler and shall not be
restrained.

38
Scale Service (Duty) Idlers
Idlers in the weighing area must be the same make, model, troughing angle and
rating and should be high quality.
Excessive
Idler
Deflection
Under Load
A00202a
Idler deflection under design load
should not exceed 0.02% of the idler
width. Reinforce if necessary.

39
• Belt scales are an important asset as they can help to maximize the use
of raw materials, control inventories, provide consistent high quality
products and be used to perform calculations (i.e. heat rate)
• Most training classes on belt scale systems devote about 75% of their
time to discussing the conveyor, because the reliability of a belt scale is
directly proportional to the fitness of the application and the quality and
maintenance of the conveyor.
• Approximately 8 out of 10 service visits are to resolve a problem with the
conveyor and its affect on the scale rather than a component failure or
problem with the belt scale system.

40
Choosing the right scale for the application:
To provide the best weighing solution to the customer, three items need to be
considered.
• What is the value of the commodity being weighed?
• Higher value material generally requires greater weighing accuracy.
MATERIAL
VALUE
TONS PER
YEAR
COST OF
2%
ERROR
COST
OF 1/4%
ERROR
$2.00 PER
TON
1,OOO,OOO $40,000 $5,000
$100.00 PER
TON
1,000,000 $2,000,000 $250,000

41
• The second consideration is the price range the customer is
shopping.
• It obviously will be difficult to sell a $20,000 device into a $10,000
budget
• On the other hand, if $20,000 is available, why settle for reduced
accuracy. In most cases, the cost of the scale can be returned in a
very short time.
• The third consideration is the competition.
• Many competitors will attempt to sell a lower accuracy scale based
on price alone!
• Knowing the application and true accuracy requirements will assist
in making the correct determination for system proposals

42
Scale Model Accuracy:
The Ramsey family of scales follows an easy method of accuracy determination.
Basically, as the number of load cells or idlers increases, so does the accuracy.
Model Cells Idlers Design Accuracy
10-101-R1 1 1 single parallelogram ±1%
10-101-R2 2 1 dual parallelogram ±1%
10-20-1 1 1 pivoted ±1/2%
10-22-2 1 2 pivoted ±1/2%
10-20-2LC 2 1 pivoted (high load) ±1/2%
10-17-2 2 2 pivoted ±1/4 to 1/2%
10-17-4 2 4 pivoted ±1/4%
10-14-3 4 3 full floating ±1/8 to 1/4%
10-14-4 4 4 full floating ±1/8 to 1/4%

43
10-101-R1
+/-1% Accuracy
10-14
+/-1/8% Accuracy
10-20
+/-1/2% Accuracy
10-17-2
+/-1/4% Accuracy

44
Micro-Tech 9101F Scale Integrator
Belt Speed Sensor
11-101F Scale Integrator

45
Integrators:
• Two basic models of Integrators available
• 11-101F
• 11-101F is a low cost, competitive fully functional integrator
• Single line display
• Analog and pulse output
• Somewhat cumbersome to wire, configure and calibrate
• Micro-Tech 9000 is a “family” of integrators
• Several versions based on same platform, with interchangeable plug-in
option boards

46
60-12C,F,ENC
60-242
60-15UB
Speed Sensor Models

47
Shaft Mount
Speed Sensor
Under the Belt
Speed Sensor
60-12C,F,ENC
60-15UB

48
Speed Sensor Ranges:
There are many different types of speed sensors. The designs apply to
different speed ranges and environments.
Model Pulse/Rev RPM Range
60-12C 50 20-200
61-12C (FM & CSA) 50 20-200
60-12F 200 3-30
60-12CHS 50 40-400
60-12ENC 500 1-240
60-242 80 6.25 - 200
60-15UB 10 <= 600 FPM

49
Belt Conveyor Scales: Model 10-101-R1 ±1%
10-101-R1 for 18"-36" Belt Widths

50
10-101-R2 for 42“-72" Belt Widths
Belt Conveyor Scales: Model 10-101-R2 ±1%

51
Belt Conveyor Scales: Model 10-20 ±1/2%

52
Model 10-17-4
Four Idler
Model 10-17-2
Dual Idler
Belt Conveyor Scales: Model 10-17 ±1/4%

53
Belt Conveyor Scales: Model 10-14-4 ±1/8%

54
Calibration Methods:
• R-Cal (Electronic Calibration)
• Test Weights
• Calibration Chain
• Material Test
Belt Conveyor Scales: Calibration

55
Belt Conveyor Scales: Electronic Calibration
Electronic Calibration
All Ramsey belt scale systems include
provisions to electronically simulate a
loaded belt. This is to be used in lieu
of calibration chains and/or static
calibration weights. This method of
calibration will produce the same, or
better, calibration accuracy than
calibration chains, when scale
calibration is being conducted without
material weighed load tests.

56
Test Weight
Belt Conveyor Scales: Static Calibration Weights

57
Bracket
Scale & Test Chain
Tension (cable)
Bracket
Calibration Chain
Belt Conveyor Scales: Calibration Chains

58
Belt Conveyor Scales: Calibration Material Test

TSCO-THERMO FISHER

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

Similaire à TSCO-THERMO FISHER

Similaire à TSCO-THERMO FISHER (20)

Plus de Techno Service

Plus de Techno Service (10)

Dernier

Dernier (20)

TSCO-THERMO FISHER