Relative-permittivity-based online monitoring system for screw conveyors

Abstract

A screw conveyor system includes a conveyor body defining a conveyor cavity. The conveyor body includes an inlet for a conveyed material and an outlet. A screw blade is rotatably connected to the conveyor body via a shaft. The screw blade extends within the conveyor cavity between the inlet and the outlet. A hanger bearing support extends from an interior surface of the conveyor body into the conveyor cavity and a hanger bearing is attached to the hanger bearing support with the hanger bearing contacting the shaft to support the screw blade. A sensor support structure is connected to the hanger bearing support and the conveyor body. A capacitive sensor is attached to the sensor support structure and includes a first conductive plate and a second conductive plate spaced apart from one another to allow the conveyed material to travel between the first and second conductive plates.

Description

BACKGROUNDField[0001]The present specification generally relates to permittivity-based sensors. More particularly, the present specification relates to online permittivity-based sensors for integration into screw conveyors for detecting dielectric properties of a material being conveyed therethrough.Technical Background[0002]Screw conveyors are commonly used to convey a wide variety particulate materials (e.g., grains, feed, various powders, etc.) within various production processes. For example, gas plants typically utilize screw conveyors in sulfur palletization plants as a medium to transfer sulfur powder prior to the powder's shipment to end users. Sulfur powders having relatively high moisture contents tend to cohere with the screw conveyor, leading to accumulation within the screw conveyor and potential inhibition of the rotation of the screw conveyor's blades. Existence or abnormal levels of moisture collection within the screw conveyor thus have the potential to disrupt oper...

AI Technical Summary

Benefits of technology

The patent text describes a system for detecting the moisture content of a material being conveyed on a screw conveyor. The system includes a sensor that is attached to the conveyor and a hanger bearing support. The sensor consists of two conductive plates that are placed between the inlet and outlet of the conveyor. The system also includes a drive unit that rotates the screw blade and a measurement system that applies a plurality of voltages to the conductive plates and measures the current flow to determine the dielectric constant of the material being conveyed. The technical effect of this system is to provide an online monitoring mechanism that identifies the need for screw conveyor cleanings to avoid plant shut downs and unnecessary costs.

Problems solved by technology

Sulfur powders having relatively high moisture contents tend to cohere with the screw conveyor, leading to accumulation within the screw conveyor and potential inhibition of the rotation of the screw conveyor's blades.

Existence or abnormal levels of moisture collection within the screw conveyor thus have the potential to disrupt operation of the screw conveyor, leading to shipment delays and / or damage to the conveyor.

Such manual cleanings are time consuming, costly, and may be performed when they are not needed (e.g., over the course of a particular cleaning period, moisture may be successfully kept out of the screw conveyor or maintained at predefined acceptable levels, eliminating the need for a cleaning).

Depending on the material being conveyed, such conveyor trips may cost manufactures hundreds of thousands or millions of dollars per year.

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