Monitor's KA / KAX
line of rotary paddle bin level indicators consist of
the most reliable, rugged and economical point level control
sensors available for detection of dry bulk materials. These
easy to install sensors are proven performers in a wide variety
of bulk materials. Monitor's paddle switches can be used to
eliminate bin overflow, maintain a predetermined material level,
indicate plugging of conveyors and pneumatic lines or provide
any of a number of level control functions. Unlike many other
available paddle units for bins and silos, Monitor's paddle
level indicators incorporate a feature that automatically shuts
off the motor of the unit when the paddle is in a stalled position,
which both extends the life of the motor and minimizes maintenance.
of Monitor's rotary paddle bin level switch is quite
simple. The unit is installed through the wall of the vessel,
so that the paddle protrudes inside the vessel. A small electric
motor drives a paddle which rotates freely in the absence
paddle is impeded by material, the motor rotates within the
housing which triggers two switches. The first switch is
a “dry” electrical contact closure that is available
to control a process function or alarm circuit. The second
switch cuts the power to the motor, preventing a locked rotor
condition, thus extending motor life. This also activates
the signaling device which is wired through that same motor
switch. When the material level drops, the loaded stretched
tension spring returns the motor to its original running
position and the unit is reactivated.
rugged, reliable design make the paddle bin level indicator
compatible with many granular, pelletized and powder bulk applications.
Monitor paddle switches can be used for high level indication
of materials over 10 lb/ft³ (160 kg/m³ ) and for
low and intermediate level indication for materials over
(80 kg/m³). Monitor paddle units can be installed almost
anywhere dry bulk materials are stored, including bins, hoppers,
silos and tanks. Monitor’s KA unit is the most popular
of our paddle bin monitors. This model is ideal for use in
standard applications with a wide variety of materials. The
KAX incorporates all the features of the KA model, but is
specially designed to meet explosion-proof standards.
Typical Applications include, but
are not limited to:
motor shutoff prevents motor burnout and extends the life
of the unit
on/off cover means no bolts to hold or lose - Hassle- free
CSA and ATEX/IECex hazardous location approvals (KAX)
or 1-1/2” BSPT process connection
conduit connections provide easy wiring access (M20 cable
glands provided with Model KA units with BSPT process connection)
slip clutch protects motor and drive gears from excessive
Three bearing design with
sealed bearings fully minimizes drive shaft loads and drag
providing extended life.
paddle assemblies increase the paddle unit’s versatility
signal delay prevents false signaling
operating temperature up to 300°F (149°C) (Hi-temp
version up to 750°F (399°C))
KA unit is the most popular of our paddle bin monitors. This
model is ideal for use in standard applications with a wide
variety of materials. The KAX incorporates all the features
of the KA model, but is specially designed to meet hazardous
This installed KA unit is being used
as a high-level alarm
in a grain storage
Monitor offers several motor voltages to serve most power requirements.
Available AC motors include 115 VAC, 230 VAC, 24 VAC and 48 VAC.
Superior 12/24 VDC design available uses low voltage AC motor
for longer life in all applications.View
DC Powered Technical Sheet (PDF).
Monitor paddle units are available with 1, 2 or 3 output contacts.
The cost effective 1-circuit model utilizes the motor switch
(SPDT) as the output contact, as long as the alarm device operates
on the same voltage as the motor. The most popular 2-circuit
design contains the motor SPDT switch and a second SPDT isolated
switch for control outputs (See wiring
diagram for illustration). The 3-circuit configuration
provides the user with the SPDT motor switch and an isolated
DPDT switch for control outputs.
Monitor offers a choice of either a 1-1/4” NPT or 1-1/2” BSPT
process connection. Model KA units with the 1-1/2” BSPT
connection also include M20 cable glands.
Monitor paddle units are available approved to UL, CSA and
ATEX/IECex requirements. Various models are approved for
either general purpose, dust/ignition-proof and/or explosion-proof
applications. In addition, all models carry the CE mark.
See “Specifications” section
for more details.
Monitor’s high temperature models incorporate all the
standard features of the KA or KAX models, but can be used
in applications where 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, shaft
extension, couplings and bushings. The high-temp assembly is
available in either a carbon steel or stainless steel version.
See “Ordering Information” for
applicable part numbers.
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
3.) Insertable* Stainless Steel,
Two Vane Collapsible Paddle: Provides low and high level
control for light to average weight materials.
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 Paddle:
Provides low and high level control for heavy materials
over 2 inch (50 mm) in diameter. Top mount only. P/N
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
is used. 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 connection.
3.) K-Flange Aluminum
Mounting Plate: For flat surfaces or thin walled
vessels where extra strength is required. Ideal for semi-corrosive
environments, including out doors. P/N 1-3316.
Dimensions are shown in inches with millimeter
equivalent in brackets.
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.
(-40°C) to +200°F (+93°C) ext. amb.;
to +300°F (+149°C) internal bin temperature.
High Temp Unit to +750°F (+399°C) internal
(2) 3/4" NPT; M20 cable glands (Model KA
units with 1-1/2” BSPT process connection
only;Not on KAX units)
SPDT 15A @ 250 VAC ea. max
SPDT 15A @ 250 VAC max
One DPDT 10A @ 250 VAC max
PSI (2 bar) maximum
lb/ft³ (80 kg/m³) minimum material density
(when using large 3-vane paddle)
cast aluminum, NEMA 4 / ENCLOSURE TYPE 4, IP66
or R 1-1/2 (BSPT 1-1/2)
6 lbs (2.72 kg)
Couplings: 304 stainless steel
Mounting Plates: Carbon steel or
304 stainless steel
All Paddles except Ex-Flex: 304 stainless
Ex-Flex Belt: 304 stainless steel
coupling, rubber/fabric blend belt
Flexible Cable Extension: 304 stainless
Solid Shaft Extension/Guards: Galvanized
or 304 stainless steel
Shaft Seal: Nitrile
and CSA: Ordinary Locations
and CSA: Class I, Div. 1 & 2, Groups
Class II, Div. 1 & 2, Groups E, F,
(Ex) II 1/2
D c T 100°C
ExtD A20/A21 T 100°C
(Ta -40°C to +93°C)
DIP A21 IP6X TA 100°C
-40°C to +93°C
Technologies LLC warrants each 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.
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.