Measuring and testing – Volume or rate of flow – By measuring electrical or magnetic properties
Patent
1996-11-06
1999-07-27
Dougherty, Elizabeth L.
Measuring and testing
Volume or rate of flow
By measuring electrical or magnetic properties
G01F 156
Patent
active
059293438
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a device for measuring the powder flow rate of a powder coating material or the like, and more particularly to a device for measuring a power flow rate as a change in capacity.
Moreover, this invention further relates to an apparatus and a method for supplying powder, which is applied, for example, in performing a powder coating by supplying a powder coating material to a spray gun.
2. Description the Related Art
In the field of automated powder coating, there is the necessity of always supplying a powder coating material at a constant rate so as to realize a uniform finish coating film and to efficiently utilize a coating material. Thus, there have been various methods for measuring a power flow rate. The applicant for the present application have proposed a method for measuring a powder flow rate while utilizing the measurement of the density of powder, and further have proposed an apparatus for performing such a method, in Japanese Patent Laid-Open No. 7-35591/1995. In accordance with this method, the density of powder is measured from various physical quantities such as light transmissivity, ultrasonic transmittance and electrostatic capacity. Then, the powder flow rate is measured from the measured value of the powder density. Thus, as compared with a conventional method for measuring a flow rate by detecting a pressure difference or the like, a powder flow rate can be measured according to this proposed method by using a very simple mechanism. Consequently, there can be realized a device for measuring a powder flow rate, whose manufacturing cost is low and maintenance is easily achieved, and color is easily changed.
Among the methods disclosed in the aforementioned Japanese Patent Laid-Open No. 7-35591/1995, the method of measuring the powder flow rate from change in the electrostatic capacity between a pair of measuring electrodes is extremely simple and convenient and thus can be used preferably. However, in the case of employing this method, the electrostatic capacity is susceptible to a change in the ambient temperature and may vary with the structure of the used electrodes and with the manner in which the electrodes are mounted. Moreover, the measured value of the electrostatic capacity may vary with the place through which the powder passes.
Furthermore, the powder sometimes adheres to the wall of a supply passage. This may cause variation in the quantity of supplied powder.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a powder flow rate measuring device which can accurately measure a powder flow rate without being affected by a change in the ambient temperature and a place through which the powder passes.
Moreover, it is another object of this invention to provide a powder supplying apparatus that can supply powder at a constant rate, and to provide a method for supplying powder at a constant rate.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a block diagram illustrating a powder supplying apparatus according to Embodiment 1 of the present invention;
FIG. 2 is a perspective diagram showing a powder flow rate measuring device used in Embodiment 1;
FIG. 3 is a sectional diagram showing the flow rate measuring device of FIG.2;
FIG. 4 is a perspective diagram illustrating a case when a nylon filament is inserted into the flow rate measuring device of FIG. 2;
FIG. 5 is a graph illustrating the relation between the number of nylon filaments and the measured value of electrostatic capacity in the case when the filaments are inserted into the flow rate measuring device of FIG. 2 and a conventional flow rate measuring device;
FIG. 6 is a schematic diagram illustrating an example of a modification of the powder flow rate measuring device;
FIG. 7 is a diagram illustrating an equivalent circuit of the apparatus of FIG. 6;
FIG. 8 is a partial cutaway sectional diagram for illustrating another powder flow rate measuring device;
FIG. 9 is a sectional diagram showing the flow rate measuring device of FIG
REFERENCES:
patent: 4270558 (1981-06-01), Forster et al.
patent: 4509366 (1985-04-01), Matsushita et al.
patent: 4619145 (1986-10-01), Girgenti
patent: 5351558 (1994-10-01), Horn et al.
patent: 5421210 (1995-06-01), Kobayashi et al.
patent: 5454271 (1995-10-01), Yamamoto et al.
patent: 5560246 (1996-10-01), Bottinger et al.
Ishikawa Yutaka
Kanai Keiji
Kumata Mitsuyoshi
Murai Hiroki
Yamamoto Masahiro
Dougherty Elizabeth L.
Nihon Parkerizing Co. Ltd.
LandOfFree
Device for measuring powder flow rate and apparatus and method f does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for measuring powder flow rate and apparatus and method f, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for measuring powder flow rate and apparatus and method f will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-880694