Reliable Level Indicators for Bins, Silos, & Hoppers
A rotary paddle level switch is the most widely used point level indicator for detecting high, mid, or low material levels in storage vessels. Designed for bulk solids—including powders, pellets, and granular materials—BinMaster rotary level indicators activate an alarm, light, or process equipment when material covers or falls away from the paddle.
BinMaster’s BMRX rotary level switches are available in standard and fail-safe models and can be customized with a wide assortment of paddles, mounting plates, shaft extensions, and process connections. A compact MINI rotary is also available for tight spaces.
ATEX and IECEx-certified models available for hazardous locations.
FORMERLY MAXIMA+
BMRX-300 Fail-Safe Rotary
The BMRX-300 fail-safe rotary paddle switch features a highly visible, lid-integrated LED indicator for instant status recognition from up to 100 feet away.
Highly Visible LED Indicator
- Green light = Paddle is rotating (the standard condition)
- Red light = Paddle is stopped (indicating a material present or fault condition)
Process Control Capability
- Wire the rotary to start or stop equipment automatically
- For example: the rotary shuts down an auger when a grain bin reaches the high level
Advanced Protection & Diagnostics
- Fail-safe operation, self-diagnostics, and immediate corrective response to failures
- Receive a visual indication of rotating, covered, or fault status
- Ideal for critical process control and overfill prevention applications
More Choices for Level Alerts
BMRX-200 & BMRX-100
The BMRX-200 rotary level switch features PCB controls and DPDT relay outputs designed to default to a safe condition during power failure.
- Fail-safe relay logic in power failure
- DPDT relay for dual switching outputs
- Ideal for high- or low-level point detection
The BMRX-100 electromechanical rotary uses a rugged mechanical design with no printed circuit board.
- SPDT switch
- Impervious to moisture and vibration
- Ideal for tough industrial processing environments
Ideal for Small Bins & Hoppers
Compact MINI Rotary
This economical, compact paddle level switch is designed for smaller bins containing plastics, food, seed, chemicals, and dry bulk solids.
- Slow-speed synchronous motor
- Adjustable torque sensitivity
- Two paddle options: a four-vane polycarbonate paddle (light to medium density materials) or the bayonet polycarbonate paddle (insertable through ¾” pipe fitting; higher density materials)
| BMRX-300 | BMRX-200 | BMRX-100 | Mini | |
|---|---|---|---|---|
| Operation | Digital PCB | Digital PCB | Mechanical | Mechanical |
| Fail-Safe | True | Power Failure | No | No |
| Switch | DPDT | DPDT | SPDT | SPDT |
| LED Indicator | Yes | No | No | No |
| Approvals | Hazardous | Hazardous | Ordinary | Ordinary |
| Time Delays | Yes | No | No | No |
| Screw-Off Cap | Yes | Yes | Yes | Yes |
| Warranty | 2-Year | 2-Year | 2-Year | 2-Year |
How a Rotary Paddle Level Switch Works
A rotary paddle switch provides point level detection in powders, pellets, and granular materials with bulk densities from 2 to over 100 lb./ft³. Rotaries are used for:
Overfill Prevention
The rotary is mounted on the roof or near the top of the bin wall for high-level detection.
• Paddle rotates freely while bin fills
• Material contacts paddle, stops rotation
• Actuator arm triggers relay switch
• Alarm, light, or equipment shuts off to prevent an overfill
Shortage Alerts
The rotary is mounted in the cone or near the bottom of the bin wall for low-level alerts.
• Paddle stops rotating while covered
• As material drops below paddle, motor re-energizes and resumes turning
• The relay activates to signal low level or start process equipment
Plugged Chutes
The rotary is mounted in a chute or in the cone of a hopper.
• Two rotaries can be used for redundancy and protection
• As bulk material builds up and contacts a rotary, its paddle stops rotation, triggering a relay switch
Conveyor Overloads
The rotary is mounted near the bottom of a vessel or in a chute.
• As conveyor feeds material, a backup may occur that reaches the level of the rotary
• The rotary paddle stops rotating, triggering the alert it is wired to: a light, horn, alarm panel, or process
Rotary Mounting Options
Mounting plates available in carbon steel or stainless steel.
Top Mounting
- Used for high-level detection
- Full coupling mounting plates in 0°, 10°, 20°, and 30° angles
- Flexible shaft coupler absorbs impact during loading
Side Mounting
- Used for low- or mid-level detection
- Half coupling mounting plate
- Solid-shaft coupler
- Mount on sidewall or bin cone
| Model | Mount | Angle | Coupling | Construction | Finish | Gasket |
|---|---|---|---|---|---|---|
| GRMP-1 | Side | 0° | Half - 1.25" | Carbon Steel | White Powder Coat | Black Neoprene |
| GRMP-3 | Side | 0° | Half - 1.25" | Stainless-Steel | Bare | Black Neoprene |
| GRMP-14 | Side | 0° | Half - 1.25" | Carbon Steel | Bare | White Silicone |
| GRMP-2 | Top | 0° | Full - 1.25" | Carbon Steel | White Powder Coat | Black Neoprene |
| GRMP-4 | Top | 0° | Full - 1.25" | Stainless-Steel | Bare | Black Neoprene |
| GRMP-15 | Top | 0° | Full - 1.25" | Stainless-Steel | Bare | White Silicone |
| GRMP-9 | Top | 10° | Full - 1.25" | Carbon Steel | White Powder Coat | Black Neoprene |
| GRMP-16 | Top | 20° | Full - 1.25" | Carbon Steel | White Powder Coat | Black Neoprene |
| GRMP-13 | Top | 30° | Full - 1.25" | Carbon Steel | White Powder Coat | Black Neoprene |
Rotary Paddle Accessories
Selecting the correct paddle ensures reliable point level detection.
- Taller paddles create greater resistance for light materials
- Most paddles are stainless steel
- Nylon paddles available for light-duty applications
- Direct-connect paddles eliminate need for coupler
- 3-vane paddles (most popular) available in multiple depths
- Bayonet/single-vane paddles insert through process connection
- Collapsible paddles fit through 1-1/4” or 1-1/2” openings
| Model | Type | Construction | Turning Diameter | Insertion Depth | Blade Height | Connection | Material Density |
|---|---|---|---|---|---|---|---|
| GRP-1 | 3-Vane | Stainless-Steel | 7.0" | 2.7" | 2.0" | Coupler | Light |
| GRP-2 | 3-Vane | Stainless-Steel | 5" | 2.2" | 1.5" | Coupler | Medium |
| GRP-3 | Single Vane, Insertable | Stainless-Steel | 4-7/16" | 2.0" | 1.0" | Coupler | Heavy |
| GRP-11 | 3-Vane | Nylon | 7.0" | 2.6" | 1-15/16" | Coupler | Light |
| GRP-12 | 3-Vane | Nylon | 5.0" | 2.1" | 1-7/16" | Coupler | Medium |
| GRP-22 | 3-Vane | Stainless-Steel | 5.0" | 2.2" | 1.0" | Coupler | Heavy |
| GRP-23 | Bayonet | Stainless-Steel | 6.4" | 6.2" | 1.2" | Coupler | Medium |
| GRP-24 | Belt | Belting | 1.5" | 13.2" | 12.0" | Coupler | Heavy w/ Lrg. Particle Size |
| GRP-25 | 3-Vane | Stainless-Steel | 5.4" | 5.7" | 5.0" | Coupler | Very Light |
| GRP-26 | 3-Vane | Stainless-Steel | 7.0" | 3.5" | 2.0" | Direct | Light |
| GRP-27 | Bayonet | Stainless-steel | 6.4" | 8.0" | 1.2" | Direct | Medium |
| GRP-28 | 3-Vane | Stainless-Steel | 7.0" | 5.7" | 5.0" | Coupler | Very Light |
| GRP-29 | 3-Vane | Stainless-Steel | 5-7/16" | 5.7" | 5.0" | Direct | Very Light |
| GRP-30 | 3-Vane | Stainless-Steel | 5.0" | 4.0" | 1.5" | Direct | Medium |
| GRP-31 | Single Vane | Stainless-Steel | 7.0" | 2.25" | 1-5/8" | Coupler | Heavy |
| GRP-34 | Single Vane | Stainless-Steel, collapsible to 1.5" NPT | 8.0" | 4.7" | 1-3/8" | Direct | Medium to Heavy |
| GRP-35 | Double Vane | Stainless-Steel, collapsible to 1.5" NPT | 8.0" | 4.8" | 1-3/8" | Direct | Medium to Heavy |
| GRP-36 | Single Vane | Stainless-Steel, collapsible to 1.5" NPT | 8.0" | 4.8" | 1-3/8" | Coupler | Medium to Heavy |
| GRP-37 | Double Vane | Stainless-Steel, collapsible to 1.5" NPT | 8.0" | 4.8" | 1-3/8" | Coupler | Medium to Heavy |
Custom Rotary Configurations
BinMaster builds custom rotary configurations at our Lincoln, Nebraska manufacturing facility, typically in just a few days.
Sealed Rotary Extension
• Protective bearing prevents material packing
• Eliminates false full signals
• Ideal for side mounting or angled rooftops
Stainless-Steel Connection
• 304 SS solid stainless-steel fitting with stainless-steel seal/bearing carrier
• Available in 1-1/4” and 1-1/2” NPT
• Ideal for corrosive, food-grade, or chemical applications
Heat Tubes
• For high-temperature applications; required when external temps exceed 140°F (60°C)
• Protects electronics from heat source
• Aluminum or stainless-steel; 8” or 12” lengths
Vertical Rotary Extension
• Custom lengths up to 144”
• Ideal for top-of-bin high-level detection
• Allows headroom management
Horizontal Rotary Extension
• For thick bin walls up to 12”
• Includes extended shaft & protective guard
• Standard lengths: 6”, 8”, 10”, 12”
Adjustable Top-Mount Rotary
• Adjustable shaft from 6” to 72”
• Ideal for variable level requirements
• Top-of-bin installation
Rotary Documents
