OMEGA LVD-800-Series Fail-Safe Dry Material Rotary Paddle Level Switches

The LVD-800 Series fail-safe bin monitor is the state-of-the-art in rotary paddle technology. Utilizing magnetic sensing technology and a unique housing design, the LVD-800 Series fail-safe bin monitor is the most reliable, technician-friendly, rugged and economical truly fail-safe rotary paddle point level control sensor of its kind.

The LVD-800 Series fail-safe bin monitor 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 LVD-800 Series fail-safe level sensor monitors its electrical and mechanical operating condition. This, in conjunction with separate outputs provided for material sense and unit status (fault conditions) makes this unit a ‘truly’ fail-safe device.

While the LVD-800 Series fail-safe bin monitor is an evolution in rotary paddle technology, it continues to use tried-and-true operating techniques. Unlike many other available units, the LVD-800 Series 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.

Principle of Operation
The operation of the LVD-800 Series rotary paddle fail-safe bin monitor uses magnetic sensing technology to detect both material presence and operational status of the unit. This method is simple and more reliable than that used by other manufacturers. 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 of material.

The rotation of the unit’s shaft is continuously monitored by detection of a magnetized rotating disk (patented). 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 (patented). Use of these magnetic sensing techniques eliminates problems that may occur with fouling of the optical systems used by other brands.

The built-in microcontroller performs self-diagnostics and monitors both shaft and motor mounting plate rotation. This allows the unit 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 deenergized 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 indicating that an error condition exists. Monitoring the state of both the SENSE and FAULT relays provides the most flexibility for control and fail-safe monitoring.

The rugged and reliable design of the LVD-800 Series fail-safe 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 160 kg/m³ (10 lb/ft³) and for low and intermediate level indication for materials over 80 kg/m³ (5 lb/ft³). The LVD-800 Series bin level monitor can be installed almost anywhere dry bulk materials are stored including bins, hoppers, silos and tanks.