Method of determining the mass flow of a flow of grains

Details Method of determining the mass flow of a flow of grains Method of determining the mass flow of a flow of grains

1998-04-13

1999-10-26

Chilcot, Richard

Measuring and testing

Volume or rate of flow

By measuring vibrations or acoustic energy

G01F 166

Patent

active

059708000

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The invention relates to a method of determining the mass flow speed of a granular material through a channel by means of electromagnetic waves, microwaves from a transmitter to a receiver. The invention relates in particular to measurements performed in moving combine harvesters, where it is important to know the quantity of grains conveyed to the grain tank of the combine harvester. The invention is, however, related to the measuring of a grain flow or a material flow in general.


BACKGROUND OF THE INVENTION

Several systems have been suggested for such a measuring of the flow, such as by means of yielding guard plates being pushed more or less backwards in response to the force they are subjected to by an incoming falling flow of the granular material. It has, however, been recognized that such mechanical measuring methods are too uncertain and that it is possible to employ a more advanced measuring technique based on radioactive radiation. Thus it has been found that it is possible to achieve a well-defined expression of the mass flow of a granular material by said flow passing a measuring area, where a radioactive radiation is emitted from one side of said measuring area towards an opposing side where a receiver detects the radiation and continuously detects the amount of radiation absorbed by the grain flow. In this manner it is possible to determine the mass flow.
Although it is thereby possible to employ radioactive sources which are in fact of a neglectable size, the Authorities have declared that such sources should be avoided because they require so much inspection that an inspection of thousands of moving units would be completely unrealistic.
According to the invention it has been recognized that it is possible to use an officially acceptable type of radiation-based mass determination. In other words it is possible to use electromagnetic microwaves in a frequency area where a predetermined quantity of radiation has been allowed. Besides it is by the present invention sufficient to employ a power of the magnitude of 1 W, whereby suitable shieldings may secure that the radiation problems are reduced to an acceptable level.
It is known from U.S. Pat. No. 4,628,830 to perform a continuous determination of the mass flow in a flow of granular material by means of microwaves. However, this publication deals only with absorption of the wave energy caused by the water content in a coal powder fed to a burner in a power station. The measuring is performed on a falling flow of the material in a pipe where a microwave generator is placed opposite a receiver. In this manner it is possible to measure the amount of energy absorbed in the material, or rather to obtain an expression of the variations applying to the mass flow and thereby to calibrate said variations into an expression of the mass flow. A measuring of the water flow is aimed at, where said water flow in a predetermined material represents the flow of the material itself for a predetermined water content.
The above is possible as long as the material in question is almost homogeneous. A fundamental condition applies, however, to combine harvesters, namely, that the measuring device must be able to operate with various types of material which in no way is homogeneous. The major advantage obtained by the use of the above radioactive radiation is indeed that it is possible to operate with a well-defined calibration of the equipment for various types of grains and seeds.
A substantially analogous use of microwaves does not provide a similar result. Tests performed on microwaves of the type being commercially used exactly for emission of energy into wet substances turned out to be extremely unfortunate, for instance in connection with absorption of energy for heating products in microwave ovens, as it turned out to be impossible by means of one and the same equipment to obtain merely tolerably correct measurements of various mass flows of various granular materials.
It has, however, nevertheless become possible by the inventi

REFERENCES:
patent: 1851215 (1932-03-01), Schunemann
patent: 4314241 (1982-02-01), La Plante et al.
patent: 5369369 (1994-11-01), Cutmore

Affiliated with

Also associated with

Rating

Method of determining the mass flow of a flow of grains does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of determining the mass flow of a flow of grains, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of determining the mass flow of a flow of grains will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-751483