Conveyor scale calibration

• US 3,899,915 A
• Filed: 11/07/1973
• Issued: 08/19/1975
• Est. Priority Date: 11/07/1973
• Status: Expired due to Term

• Current Assignee: Toledo Scale Corporation 350 W Wilson Bridge RD Worthington Oh
• Original Assignee: Richard A. Cherry, Richard C. Loshbough, Roger B. Williams Jr
• Inventors: Williams, Roger B. Jr., Loshbough, Richard C., Cherry, Richard A.
• Primary Examiner(s): Swisher, S. Clement
• Application Number:
  US05/413,657
• Time in Patent Office: 650 Days
• Field of Search: 73/1R,1B,2 177/50,245
• US Class Current: 73/1.13
• CPC Class Codes: G01G 11/006 Special taring or checking devices therefor devices for determining tare weight in general G01G23/14

Abstract

Apparatus and a method for calibrating a conveyor scale which measures at least the rate at which material is carried through a region by a conveyor. The scale is of a type which generates a first electric signal corresponding to the speed of the conveyor, a second electric signal corresponding to the material weight within the region and from these signals generates a third signal corresponding to the material transfer rate. During calibration of the conveyor scale, an electric signal is generated to correspond to a simulated conveyor speed. The simulated speed signal is used in combination with a predetermined weight signal for obtaining a transfer rate signal. The weight signal is generated either by placing the predetermined weight on the stopped conveyor or by an electric signal generator which simulates the predetermined weight. The conveyor scale is then calibrated such that the indicated transfer rate corresponds to an actual transfer rate determined from the simulated conveyor speed and the predetermined material weight. The apparatus and method also may be used to calibrate a conveyor scale which measures the total weight of material transferred over a period of time.

Claims

1. Measuring apparatus for use with a conveyor for moving material through a region comprising, in combination, means for generating an electric speed signal corresponding to the speed of the conveyor, means for generating an electric weight signal corresponding to the weight of material in the region, multiplying means responsive to said speed and weight signals for generating an electric signal which is a measure of the weight transfer rate, and means for calibrating said measuring apparatus, said calibrating means including means for applying to said multiplying means a weight signal corresponding to a predetermined weight, means for generating an electric signal for simulating said speed signal at a predetermined constant conveyor speed, switch means for selectively applying said simulated speed signal to said multiplying means in place of said conveyor speed signal whereby said weight transfer rate signal is generated in response to said simulated speed signal and said predetermined weight signal, and means for adjusting said measuring apparatus to eliminate any deviation in said weight transfer rate signal from a true weight transfer rate signal for such predetermined constant conveyor speed and predetermined weight in the region.

2. Measuring apparatus for use with a conveyor for moving material through a region, as set forth in claim 1, wherein said means for applying to said multiplying means a weight signal corresponding to a predetermined weight includes means for generating a signal for simulating said predetermined weight in the region, and second switch means for selectively applying said simulated weight signal to said multiplying means in place of said weight signal.

3. Measuring apparatus for use with a conveyor for moving material through a region, as set forth in claim 1, and further including integrating means responsive to said weight transfer rate signal over a period of time for geNerating a signal corresponding to the total weight of material transferred through the region during such period of time.

4. Measuring apparatus for use with a conveyor for moving material through a region, as set forth in claim 3, and wherein said means for calibrating said measuring apparatus further includes means for measuring a time interval during which said simulated speed signal and said predetermined weight signal are applied to said multiplying means, and means for adjusting said measuring apparatus to eliminate any deviation in said total weight signal from a true total weight signal for such predetermined conveyor speed and predetermined weight.

5. Measuring apparatus for use with a conveyor for moving material through a region, as set forth in claim 4, wherein said means for applying to said multiplying means a weight signal corresponding to a predetermined weight includes means for generating a signal for simulating said predetermined weight in the region, and second switch means for selectively applying said simulated weight signal to said multiplying means in place of said weight signal.

6. Measuring apparatus for use with a conveyor for moving material through a region comprising, in combination, means for generating an electric speed signal corresponding to the speed of the conveyor, means for generating an electric weight signal corresponding to the weight of material in the region, means responsive to said speed and weight signals over a predetermined period of time for generating an electric signal which is a measure of the total weight of material transferred through the region during said period of time, and means for calibrating said measuring apparatus, said calibrating means including means for applying to said total weight signal generating means a weight signal corresponding to a predetermined weight, means for generating an electric signal for simulating said speed signal at a predetermined constant conveyor speed, switch means for selectively applying said simulated speed signal to said total weight signal generating means in place of said conveyor speed signal whereby said total weight signal is generated in response to said simulated speed signal and said predetermined weight signal, and means for adjusting said measuring apparatus to eliminate any deviation in said total weight signal from a true total weight signal for such predetermined conveyor speed and predetermined weight over said period of time.

7. Measuring apparatus for use with a conveyor for moving material through a region, as set forth in claim 6, wherein said means for applying to said total weight signal generating means a weight signal corresponding to a predetermined weight includes means for generating a signal for simulating said predetermined weight in the region, and second switch means for selectively applying said simulated weight signal to said total weight signal generating means in place of said weight signal.

8. A method for calibrating a conveyor scale which measures material transferred through a region by a conveyor, said scale having means for generating a signal corresponding to the speed of the conveyor, means for generating a signal corresponding to the material weight within the region, and multiplying means responsive to said conveyor speed signal and said material weight signal for generating a signal corresponding to the material transfer rate, said method comprising the steps of:

generating an electric signal for simulating a predetermined conveyor speed, applying said simulated speed signal to said multiplying means, applying a signal to said multiplying means corresponding to a predetermined material weight in the region, and adjusting said conveyor scale to generate a transfer rate signal corresponding to a true transfer rate signal for the simulated conveyor speed and the predetermined material weight within the region.

9. A method for calibrating a conveyor scale, as set forth in claim 8, wherein said predetermiined material weight signAl is applied to said multiplying means by placing a test weight corresponding to said predetermined weight on said weight signal generating means while said conveyor is stopped.

10. A method for calibrating a conveyor scale, as set forth in claim 8, including the step of generating a signal to simulate said predetermined weight in the region and wherein said predetermined material weight signal applied to said multiplying means is the simulated predetermined weight signal.

11. A method for calibrating a conveyor scale which measures material transferred through a region by a conveyor, said scale having means for generating a signal corresponding to the speed of the conveyor, means for generating a signal corresponding to the material weight within the region, and means responsive to said conveyor speed signal and said material weight signal over a period of time for generating a signal corresponding to the total weight of material transferred during such period of time, said method comprising the steps of:

generating an electric signal for simulating a predetermined conveyor speed, simultaneously applying to said total weight signal generating means said simulated speed signal and a signal corresponding to a predetermined material weight in the region for a measured period of time, and adjusting said conveyor scale to generate a total weight signal after such period of time corresponding to a true total weight signal for the simulated conveyor speed and the predetermined material weight within the region during the period of time.

12. A method for calibrating a conveyor scale, as set forth in claim 11, wherein said predetermined material weight signal is applied to said total weight signal generating means by placing a test weight corresponding to said predetermined weight on said weight signal generating means while said conveyor is stopped.

13. A method for calibrating a conveyor scale, as set forth in claim 11, including the step of generating a signal to simulate said predetermined weight in the region and wherein said predetermined material weight signal applied to said total weight signal generating means is the simulated predetermined weight signal.