Method Of And Apparatus For Ascertaining The Density Of A Stream Of Fibrous Material

What is this patent about?

'075 is related to the field of measuring the density of fibrous materials, particularly in the context of tobacco processing for manufacturing cigarettes and other smoking products. Existing methods either used nuclear radiation, which is dangerous and expensive, or visible light, which is less reliable. The patent addresses the need for a safe and accurate method for continuously monitoring the density of tobacco flows in high-speed cigarette-making machines.

The underlying idea behind '075 is to use multiple X-ray beams to measure the density of a tobacco rod. Instead of a single beam and detector, the invention uses an array of X-ray beams and corresponding detectors to measure the density of small, discrete portions of the tobacco filler. By processing the signals from these detectors, a more accurate and high-resolution density measurement can be obtained.

The claims of '075 focus on an apparatus for ascertaining the density of a flow of fibrous material, comprising: a means for directing multiple X-ray beams through different portions of the flow; a linear array of X-ray detectors that generate first signals corresponding to the intensity of each beam after passing through the material; and a processing unit that combines these first signals into a single second signal representing the overall density of the flow.

In practice, the apparatus directs X-ray beams through the tobacco rod, and the linear array of detectors measures the intensity of each beam after it has passed through the tobacco. The processing unit then takes these intensity measurements and processes them, including compensating for any drift in the detectors or fluctuations in the X-ray source. This compensation is achieved using reference beams that bypass the tobacco and dark signals from shielded detectors. The signals are then combined, often through logarithmizing and summing, to produce a final density measurement.

This approach differs from prior art by using multiple X-ray beams and detectors to achieve higher resolution and accuracy. The use of reference and dark signals allows for continuous calibration and compensation, minimizing the impact of external factors on the density measurement. By measuring the density of small, uniform portions of the tobacco rod and then mathematically combining these measurements, the invention provides a more reliable and accurate density reading than previous methods that relied on single beams or less sophisticated signal processing.