ROTARY PADDLE BIN MONITOR

BULLETIN 213

Monitor's line of rotary paddle bin monitors consists of the most reliable, rugged and economical point level control sensors available for detection of dry bulk materials. These easy to install units are proven performers in a wide variety of bulk materials. Monitor's paddle units 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, 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.

Principle of Operation

The operation of Monitor's paddle level control products 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 of material.

When the 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.

Applications

Monitor’s rugged, reliable design make the paddle units compatible with many granular, pelletized and powder bulk applications. Monitor paddle units 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 5 lb/ft³ (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.

Features

Available Models

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 hazardous location standards.

This installed KA unit is being used
as a high-level alarm in a grain storage
application.

Available Configurations

MOTOR VOLTAGES
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 lie in all applications.

OUTPUT CIRCUITS
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.

PROCESS CONNECTIONS
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.

APPROVALS/LABELING
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.

HIGH TEMPERATURE UNITS
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.

Accessories

PADDLE ASSEMBLIES
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. See Monitor’s Material Characteristic Guide for more detailed application recommendations.

Dimensions are shown in inches with millimeter equivalent in brackets.

MOUNTING PLATES
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.

1.) 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.

2.) 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.

SHAFT EXTENSIONS
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
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.

Specifications

Warranty

Monitor 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.

213.12.0306

Global Flour Processor Uses Flexar® Guided Wave Radar

A large global flour processor and food products company recently began using the Flexar® guided wave radar in a total of eighteen (18) silos and bins to manage their finished product inventory.  Readings from these continuous level sensors is reported as being reliable and accurate, even during pneumatic filling, contrary to their previous measuring system.  A previous non-performing ultrasonic system was replaced by the Flexar level sensors.  Flexar guided wave radar level sensors were chosen as the best for pneumatically filled dust laden flour silos.

Eight (8) Flexar level sensors are installed in load-out silos that fill bulk trucks with processed and finished flour.  These silos are 12ft in diameter and 35ft tall.  The finished flour is pneumatically conveyed into these silos.  During filling the internal environment of the silos is very dusty and turbulent.  The finished flour in these silos is used for loading bulk transport trucks for distribution.  In addition, ten (10) Flexar level sensors are installed in 40ft high bins that contain bran.  This material is also sent by bulk transport to end users.

All of the Flexar level sensors are equipped with an RS485 digital communications output that is connected to a PC with a graphical user interface for inventory management purposes.  Monitor’s SiloTrack™ inventory management software is used by the facility to monitor and manage material inventories of both the finished flour and the bran.  SiloTrack allows for multiple user viewing and data access via LAN and this is how the facility will be using the software that provides a flexible, graphical user interface, alarms, report generation and history analysis functions.

Guided wave radar is especially well suited to level measurement applications of dusty powder materials even when measuring during pneumatic filling.  Flexar guided wave radar utilizes TDR (time domain reflectometry) technology.  Radar pulses are continuously transmitted down the sensor’s probe and guided to the material surface where they are reflected back to the electronics along the wave guide.  The time-of-flight of the pulses is measured and directly related to the distance to the material surface and its level.

>>Click here for more information about Flexar guided wave radar continuous level measurement sensors.
>>Download Product Bulletin 353A
>>Click here to visit our Flexar Website