a bin level switch that is more than just an indicator of
the presence or absence of material. Picture technology that
allows intelligent devices to indicate when something is
wrong. Dream that a level sensor provides real-time information
when the quality of the sensor function no longer allows
it to operate as you expect. That is a “self-validating” bin
level indicator. Now you can wake up, your dream has arrived.
Costly overfilling and outages due to sensor failure can now
The SafePoint® self-validating
bin level indicator from Monitor is the state-of-the-art
in rotary paddle technology. Going beyond traditional fail-safe
sensor technology that only protects against power failure,
the SafePoint bin monitor is the most reliable, rotary paddle
point level control sensor available.
The SafePoint bin level switch provides the ultimate in
performance wherever critical continuous operation must be
ensured. Detection of both material presence and its own operational
status is performed on a continuous basis.
The SafePoint level
sensor monitors its electrical and mechanical operating condition.
This, in conjunction with separate outputs for material sense
and unit status (fault conditions) make the SafePoint a "truly" fail-safe,
While the SafePoint level switch is an evolution in rotary
paddle technology, it continues to use tried-and-true operating
techniques. Unlike many other available units, the SafePoint
incorporates a feature that automatically shuts off its motor
when the paddle is in a stalled condition. This extends the
life of the unit and minimizes maintenance.
The operation of the
SafePoint® rotary paddle bin monitor uses patented technology
to detect material presence and operational status of the
unit. The unit is installed through the wall of the vessel
so that the paddle protrudes inside the vessel. A small electric
motor drives the paddle, which rotates freely in the absence
The rotation of the
unit’s shaft is continuously monitored by detection
of a magnetized rotating disk. When the paddle is impeded
by material, the shaft rotation stops. The motor rotates
within the housing and magnetized sections of the motor mounting
plate are detected. Use of these patented magnetic sensing
techniques eliminates problems that occur with fouling of
the optical systems used by other brands.
The built-in microcontroller performs self-validating diagnostics and monitors both shaft and motor mounting plate rotation. This allows the SafePoint to easily distinguish between material presence and any electrical and mechanical failure of the unit. When material presence is detected, the SENSE relay changes state and the drive motor is de-energized to extend motor life. This output is available to control a process function or alarm circuit. When the material level drops, a tension spring returns the drive motor to its original running condition and is reactivated.
A unit failure is detected
by sensing a lack of shaft rotation while material presence
has not been detected by rotation of the motor mounting plate.
In a failure condition the independent FAULT relay will change
state. Monitoring the state of both the SENSE and FAULT relays
provides the most flexibility for control and monitoring
that is beyond being just “fail-safe”.
rugged and reliable fail-safe design of the SafePoint® bin
monitor makes it the best choice for critical level control
applications. The unit is compatible with many granular,
pelletized and powder bulk applications. It can be utilized
for high level indication of materials over 10 lb/ft³ (160
kg/m³ ) and for low and intermediate level indication for
materials over 5 lb/ft³ (80 kg/m³ ). The SafePoint bin
level monitor can be installed almost anywhere dry bulk materials
are stored including bins, hoppers, silos and tanks.
Typical Applications include, but
are not limited to:
operation monitors electrical and mechanical status for
critical applications - beyond "fail-safe"
of magnetic sensing technology ensures reliable operation
even in dusty environments
on/off cover for convenient and easy access - No bolts
to lose or hold
electronics ensures consistent and reliable operation
SPDT relays for material sense and fault outputs
(7)Local Indication (ordinary
locations only) of operating status
aluminum housing with rugged powder coat finish
Temperature version available (up to 750°F/399°C)
The SafePoint® fail-safe
rotary paddle bin monitor is available in configurations
to serve 115VAC, 230VAC and
24VAC/DC power requirements.
VISUAL STATUS INDICATION
The SafePoint bin
monitor incorporates a red and green LED to indicate material
sense and unit status. A red LED illuminates when material
presence is detected. A green LED illuminates when material
is not present. The green LED will flash during initialization
immediately following power-up. The red LED will flash
during a failure mode. This indication can be viewed without
removing the cover (units supplied for general purpose
ordinary electrical locations only).
The SafePoint bin
monitors are available approved to CSA (CSA(US/C) for North
American use) and ATEX/IECex requirements. Approvals for
either general purpose, dust-ignition-proof and/or explosion-proof
hazardous area locations can be provided. All
units carry the CE mark. Refer to "Specifications" for
The SafePoint high
temperature model incorporates all the standard features
of the SafePoint bin monitor, but can
be used in applications where internal bin temperatures
reach as high as 750°F
(399°C). The hi-temp models incorporate a specially
designed mounting plate, pipe extension with air purge connection
(recommended for all high temperature applications; must
be used for 500°F/260°C), shaft extension, couplings
and bushings. The high-temp assembly is available in either
a carbon steel or stainless steel version.
Monitor offers a variety of interchangeable paddle assemblies
to meet the needs of a wide variety of applications. Different
material densities, particle sizes and flow characteristics require
specific paddles to provide optimum performance. View
Paddle Assembly Selection Guide (PDF).
are shown in inches with millimeter equivalent in brackets.
Standard Stainless Steel Three Vane Paddle: The most
popular of all paddles. For use with average weight
Large Stainless Steel Three Vane Paddle: Provides accurate
level control for lightweight materials. P/N 1-4141
Stainless Steel, Two Vane Collapsible Paddle: Provides
low and high level control for average weight
P/N 1-4161 Click
Here For Product Sheet
Insertable* Stainless Steel, Scimitar Single Vane Paddle:
Provides low and high level control for light to average
Insertable*, Stainless Steel Single Vane Paddle: Provides
low level control for average weight materials and
low to high level control for heavy materials under 1-1/2
inch (40 mm) in diameter. P/N 1-4145
Stainless Steel, Two Vane Paddle: Provides low and
high level control for heavy materials under 1-1/2 inch(40
mm) in diameter. P/N 1-4135
Stainless Steel Four Vane Paddle: For use with average
to heavy weight materials in low and high level control
Stainless Steel Triangular Arc Single Vane Paddle:
Provides low and high level control for light to average
weight materials. P/N 1-4144
Ex-Flex Three-Ply 20 inch (508 mm) Belt Vane Paddle:
Provides low and high level control for heavy materials
over 2 inch (50 mm) in diameter. Top mount only.
paddles eliminate the need for a mounting plate. P/N
1-4161 and 1-4193 are insertable through either
a half or full 1-1/4” or 1-1/2” coupling,
that is welded to the bin wall. P/N 1-4145 is insertable
through a half 1-1/4” or 1-1/2” coupling.
The flexible coupling works to absorb heavy loads, side
loads and loads caused by product surges, thus protecting
the internal workings and extending the life of the paddle
unit. A flexible coupling should be used with heavy materials
and in top mount installations where a solid shaft extension
Monitor offers the following coupling option:
Spring-Flex: P/N 1-3335
Mounting plates allow the paddle units to be mounted from the
outside of a vessel to curved or flat surfaces. All mounting
plates featured below mount via six bolts.
Half Coupling Mounting Plate: For use in side mount installations.
Available in powder coated carbon steel for general purpose
applications and stainless steel for use in corrosive environments.
Stainless Steel Plate: P/N 1-0112. Carbon Steel Plate: P/N
1-0101 for 1-1/4” NPT connection and P/N 1-0100 for
1-1/2” BSPT connection.
Full Coupling Mounting Plate: For use in top mount installations
where a shaft extension and shaft guards are required. Available
in powder coated carbon steel for general purpose applications
and stainless steel for use in corrosive environments. Stainless
Steel Plate: P/N 1-0113. Carbon Steel Plate: P/N 1-0102 for
1-1/4" NPT connection and P/N 1-0115 for 1-1/2" BSPT
K-Flange Aluminum Mounting Plate: For flat surfaces or thin
walled vessels where extra strength is required. Ideal for
semi-corrosive environments, including outdoors. P/N 1-3316.
Many top mount installations require that the paddle
extends into the vessel to a predetermined level. Solid
shaft extensions are available in a variety of lengths
up to 144 inches (3.6 m) to meet these demands. A flexible
cable extension is also available. This 6.5 foot (2.0
m) flexible extension can be easily shortened in the
field by the user. The use of the flexible cable extension
for lengths greater than 3 feet (0.9m) requires the use
of a guard to ensure proper activation of the rotary
paddle bin monitor.
Shaft guards are recommended for use with solid shaft extensions
to limit the movement caused by side loading that would otherwise
damage the working components of the paddle unit. Shaft guards
should be the same length as the extension and should always
be used when the extension meets or exceeds 18 inches (460
mm) in length.
3/4” NPT; M20 cable glands (Ordinary Location
units with 1-1/2” BSPT process connection
only; Not provided on Haz Loc units)
SPDT; 5A @ 250 VAC, 30 VDC max
SPDT; 5A @ 250 VAC, 30 VDC max
PSI (2 bar)
lb/ft³ (80 kg/m³ ) minimum material density
(when using large 3-vane paddle)
and green high intensity LEDs indicate material
sense and unit status conditions (Ordinary Location
cast alum., NEMA 4 / ENCLOSURE TYPE 4, IP66
or R 1-1/2 (BSPT 1-1/2)
6-1/2 lbs (2.95 kg)
Couplings: 304 stainless steel
Mounting Plates: Carbon steel or
304 stainless steel
All Paddles except Ex-Flex: 304 SS
Ex-Flex Belt: 304 SS
coupling, rubber/fabric blend belt
Flexible Cable Extension: 304 SS
Shaft Seal: Nitrile
CSA(US/C): Ordinary Locations; Class I,
Groups C, D; Class II,
(Ex) II 1/2 D c T 85°C
ExtD A20/A21 T 85°C
(Ta -40°C to +65°C)
DIP A21 IP6X TA 100°C
-40°C to +65°C
Technologies LLC warrants each SafePoint® rotary
paddle bin indicator it manufactures to be free from defects
in material and workmanship under normal use and service
within two (2) years from the date of purchase. The purchaser
must give notice of any defect to Monitor within the warranty
period, return the product intact and prepay transportation
charges. The obligation of Monitor Technologies LLC under
this warranty is limited to repair or replacement at its
factory. This warranty shall not apply to any product which
is repaired or altered outside of the Monitor Technologies
LLC factory, or which has been subject to misuse, negligence,
accident, incorrect wiring by others or improper installation. Monitor
Technologies LLC reserves the right to change the design
and/or specifications without prior notice.
PATENT 6,696,965 B2
Last Rev.: June 29, 2012
Spotlight: True Fail Safe Level Switch
"Truly" Fail-Safe Level Switch
SafePoint® rotary paddle level switch with a self-validating design
detects material presence plus continuously monitors its own ability
to function. The analysis includes sensor health and system power
failure, which makes the SafePoint truly fail-safe.
The SafePoint incorporates patented use of Hall-Effect technology,
dual outputs to indicate both material presence and unit health,
and microcontroller technology to continuously protect bulk solids
processing and storage from the consequences of unknown sensor
failure by providing immediate indication of a sensor failure
and confirmation of proper operation.
Other practical features of the SafePoint include rugged construction,
motor shut-off when paddle becomes impeded to maximize motor life, twist On/Off
cover for bolt free removal, and local status indicating light (except hazardous
A practical application for the SafePoint would be to use this "true"
fail-safe product if undetected sensor failure could result in a
catastrophic process problem.