Dispensing – Automatic control – Constant weight – volume or pressure control by output
Patent
1986-11-06
1990-07-31
Shaver, Kevin P.
Dispensing
Automatic control
Constant weight, volume or pressure control by output
222 58, 222 77, 177 50, G01G 1114
Patent
active
049444280
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to an apparatus for the automatic determination of a continuous bulk material throughput by means of a continuous balance, comprising a weighing vessel, an adjustable closure member for adjusting the outlet cross-section of the weighing vessel and electronic weight difference measuring means. The invention also relates to a process for the automatic determination of a bulk material throughput in such an apparatus.
Apparatus of the foregoing type have been known. For example CH-A-557 060 discloses a process and an apparatus for the automatic determination of a bulk material flow. The basic idea used in this prior art is essentially based on the deflecting action of a butt or deflecting plate (baffle plate). Thus, if a falling bulk material flow is deflected by a butt or baffle plate placed An its line of fall, a momentum acts on said plate. The momentum force is dependent on the height of fall of the in each case instantaneous bulk material through-put and is also influenced by the position, shape and friction characteristics of the plate, but particularly by the bulk material behaviour. Other influencing parameters are the product granulation, flow behaviour, air and product moisture, temperature, etc. This list in itself shows that for the continuous determination of the mass flow of the flowing product very complex relationships are involved, despite the constructional simplicity of the actual baffle plate used. The problems which occur could only be solved in practice by accepting as invariable quantities certain framework conditions. Thus, the first restriction was that the deflecting plate system can only be used for really freely flowing material, such as grain. The product flow must be guided by geometrically constant conditions. It is theoretically conceivable to use the momentum established by the measuring or test plate for determining a bulk material throughput.
However, it has been found that the more practicable and appropriate way is to use the horizontal component of the momentum only, as is shown e.g. by DE-C-2 609 167 as a further development of the aforementioned CH-A-557 060.
The vertical component of the momentum, i.e. the "weight component", is eliminated in this type of test plate system by corresponding articulated supports for measured value determination. The horizontal deflection or the corresponding horizontal component from the interplay of the falling bulk material flow and the deflecting plate can in this way be used as a measured or test value for the automatic determination of the throughput of the bulk material flow.
Under laboratory conditions, this method makes it possible to obtain a measurement accuracy of .+-.0.5% and in very many cases .+-.1%. However, under more difficult conditions larger deviations individually appear. However, it is conventional practice to regularly guarantee bulk material balance accuracies of .+-.0.1%.
However, in all cases where balance accuracy is required, balances are still used although they are unable to measure a continuous bulk material flow and must instead interrupt the product flow for weighing purposes. In addition, balances are not only more expensive than systems with deflecting plates, but frequently need compensating elements, so that after the container balances a continuous product flow is obtained again. Conveyor scales or weighers with a high accuracy are even more expensive than container balances and often do not achieve the accuracy of the latter.
In the case of the presently observed intense automation efforts, particularly in mills, increasing importance is being attached to the following two points: fluctuation; product flow approximately with balance accuracy.
Of late, so-called differential balances have often been used, such as is e.g. shown by FR-A-2 456 344. The differential balance comprises a weighing container with a controlled product discharge, as well as a dosing means controlled by said container. The weighing container measures the material removed from th
REFERENCES:
patent: 3124206 (1964-03-01), Burke
patent: 3135427 (1964-06-01), Siegburg
patent: 3160328 (1964-12-01), Rutherford
patent: 3319828 (1967-05-01), Maxwell
patent: 3853190 (1974-12-01), Delesdernier
patent: 3889848 (1975-06-01), Ricciardi et al.
Engineering, Band 223, No. 10, Oct. 1983, London (GB), "Electronically-Controlled Hopper Copes with Sticky Materials", siehe circle 271.
Technisches Messen, Band 47, No. 4, Apr. 1980, Munchen (DE), T. Albertz: "Massenstrommessung in Stauben", pp. 137-140, see p. 137, right hand col., last paragraph, p. 138, left hand col.
Gmur Bruno
Kuhnemund Bernd
LandOfFree
Apparatus for the automatic determination of a continuous bulk m does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for the automatic determination of a continuous bulk m, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for the automatic determination of a continuous bulk m will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1394409