Apparatus and method for calibrating manifolded tanks

• US 5,544,518 A
• Filed: 06/02/1995
• Issued: 08/13/1996
• Est. Priority Date: 06/02/1995
• Status: Expired due to Term

• Current Assignee: Veeder-Root Co (Vontier Corp.)
• Original Assignee: Veeder-Root Co (Vontier Corp.)
• Inventors: Hart, Robert P., Malinin, Leonid M.
• Primary Examiner(s): RAEVIS, ROBERT R
• Application Number:
  US08/459,122
• Time in Patent Office: 438 Days
• Field of Search: 73/1 H, 73/149, 73/49.2 T, 364/509, 364/571.02
• US Class Current: 73/1.73
• CPC Class Codes: G01F 1/007 by measuring the level variations of storage tanks relative to the time
• CPC Class Codes: G01F 17/00 Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies measuring linear dimensions to determine volume G01B
• CPC Class Codes: G01F 25/0084 for measuring volume
• CPC Class Codes: G01F 25/20 of apparatus for measuring liquid level

Abstract

An apparatus and method are provided for calibrating manifolded liquid storage tanks. The apparatus includes sensors disposed within the tanks for sensing the liquid levels in each of the tanks and a metering device for measuring the amount of liquid dispensed into or out of the storage tanks. A processor is also provided which determines the amount of liquid dispensed from each tank based on liquid level measurements obtained during idle periods following dispensing periods. Once this information is obtained, single tank calibration techniques are employed. An alternate combined tank calibration can also be used. This method does not separate out the amount of liquid dispensed from each tank, but rather utilizes the combined amount dispensed. From this simpler, but less accurate method, an "equivalent" combined tank chart or combined mathematical formula may be generated using the metered amounts and a combined height amount. Heights from the two tanks may be simply averaged. The processor may be programmed to perform either or both methods.

Claims

1. An apparatus for calibrating manifolded liquid storage tanks, comprising:

(a) sensors disposed within the tanks, said sensors sensing liquid levels in each of the tanks and providing first and second output signals;

(b) at least one metering device for measuring the amount of liquid being dispensed into or out of the storage tanks and providing third output signals; and

(c) a processor having first and second inputs for receiving said first and second output signals, and a third input for receiving said third output signals, said processor being operative;

to store a first set of data values including a plurality of ratios of changes in liquid levels in one tank to associated changes in liquid levels in the other tank, said liquid levels used in determining said changes being measured by the sensors during a plurality of idle periods following associated dispensing periods and at a plurality of different liquid levels of the liquid in the tanks.

2. The apparatus according to claim 1, wherein the processor is further operative to determine the dimensions of the tank based on a second set of data values which represent the amount of liquid dispensed into or out of each tank during a plurality of dispensing periods, said processing means being programmed with an algorithm to compute the amount of liquid dispensed into or out of each tank based on liquid level measurements made immediately before dispensing and immediately following dispensing.

3. The apparatus according to claim 2, wherein said algorithm employs at least one mathematical expression for computing the volumes of the liquid in each of the tanks immediately prior to dispensing and immediately following dispensing, said computed volumes being used in determining the amount of liquid dispensed into or out of each tank during said dispensing periods, and said at least one mathematical expression being based on the height of liquid in the tanks at said plurality of dispensing periods and the dimensions of the tanks.

4. The apparatus according to claim 3, wherein the processor is further operative to store a third set of data values corresponding to the amounts of liquid dispensed into or out of each tank during the plurality of dispensing periods, said third set of data values being determined using said ratios corresponding to the heights of liquid in the tanks at said plurality of dispensing periods.

5. The apparatus according to claim 1, wherein the processor is further operative to determine the dimensions of the tank based on a second set of data values which represent the differential amounts of liquid dispensed into or out of each tank per unit of differential height change during a plurality of dispensing periods, said processing means being programmed with an algorithm to compute the differential amounts of liquid dispensed into or out of each tank per unit of differential height change based on the liquid level measurements.

6. The apparatus according to claim 5, wherein said algorithm employs at least one mathematical expression for computing the amount of liquid dispensed into or out of each tank per unit of differential height, said mathematical expression being based on the height of the liquid in the tanks at said plurality of dispensing periods and dimensions of the tanks.

7. The apparatus according to claim 6, wherein the processor is further operative to store a third set of data values including a plurality of ratios of changes in volumes to associated changes in liquid levels for each tank, said liquid level measurements used in determining said associated changes being taken by the sensors during a corresponding plurality of dispensing periods, wherein each change in volume is a function of the change in liquid level ratio corresponding to the liquid level at or near which the change in volume is being determined and the amount of liquid dispensed which is measured by the at least one metering device during the dispensing period at which the change in volume is being determined.

8. An apparatus for calibrating manifolded tanks, comprising:

(a) sensors disposed within the tanks, said sensors sensing liquid levels in each of the tanks and providing first and second output signals;

(b) at least one metering device for measuring the amount of liquid being dispensed into or out of the storage tanks and providing third output signals;

(c) a processor having first and second inputs for receiving said first and second output signals, and a third input for receiving said third output signals, said processor being operative;

i. to determine the dimensions of the tanks based on a first set of data values which represent estimates of the amount of liquid dispensed into or out of the combined tank corresponding to measured liquid levels in the tanks as sensed by said sensors, said processor being programmed with an algorithm for computing said first data values from said first and second output signals; and

ii. to store a second set of data values derived from said third output signals, said second set of data values corresponding with actual volumetric quantities of metered liquid, which volumetric quantities are related to said measured liquid levels.

9. The apparatus according to claim 8, wherein said algorithm employs at least one mathematical expression for computing said first data values from said measured liquid levels based on the dimensions of the tanks.

10. In a method of calibrating manifolded liquid storage tanks, said method comprising the step of:

generating a first set of data values including a plurality of ratios of changes in liquid levels in one tank to associated changes in liquid levels in the other tank, said liquid levels used in determining said changes being measured during a plurality of idle periods following a corresponding plurality of dispensing periods and at a plurality of different liquid levels of the liquid in the tanks.

11. The method according to claim 10, further comprising the step of generating a second set of data values which represent estimates of the amount of liquid dispensed into or out of each tank during a plurality of dispensing periods, said step of generating said second set of data values being carried out using an algorithm to compute the amount of liquid dispensed into or out of each tank based on liquid level measurements made immediately before dispensing and immediately following dispensing.

12. The method according to claim 11, wherein said algorithm employs at least one mathematical expression for computing the volumes of the liquid in the tanks immediately prior to dispensing and immediately following dispensing, said volumes being used in determining the amount of liquid dispensed into or out of each tank, said mathematical expression being based on the height of the liquid in the tanks at said plurality of dispensing periods and the dimensions of the tanks.

13. The method according to claim 12, further comprising the step of generating a third set of data values corresponding to the amounts of liquid dispensed into or out of each tank during the plurality of dispensing periods, said third set of data values being determined using said ratios corresponding to the heights of the liquid in the tanks at said plurality of dispensing periods.

14. The method according to claim 10, further comprising the step of generating a second set of data values which represent estimates of the differential amount of liquid dispensed into or out of each tank per unit of differential height change during a plurality of dispensing periods, said step of generating said second set of data values using an algorithm to compute the differential amount of liquid dispensed into or out of each tank per unit of differential height based on liquid level measurements.

15. The method according to claim 14, wherein said algorithm employs at least one mathematical expression for computing the amount of liquid dispensed into or out of each tank per unit of differential height, said mathematical expression being based on the height of the liquid in the tanks at said plurality of dispensing periods and dimensions of the tanks.

16. The method according to claim 15, further comprising the step of generating a third set of data values including a plurality of ratios of changes in volumes to associated changes in liquid levels for each tank, said liquid level measurements used in determining said associated changes being taken during a corresponding plurality of dispensing periods, wherein each change in volume is a function of the change in liquid level ratio corresponding to the liquid level at or near which the change in volume is being determined and the amount of liquid dispensed which is measured by the metering means during the dispensing period at which the change in volume is being determined.

17. In a method of calibrating manifolded tanks, said method comprising the steps of:

i. generating a first set of data values which represent estimates of the amount of liquid dispensed into or out of the combined tank corresponding to measured liquid levels in the tanks, said step of generating said first set of data values being carried out using algorithm for computing said first data values from said measured liquid levels; and

ii. generating a second set of data values corresponding to the amount of liquid dispensed into or out of the combined tank as measured by a metering means, said second set of data values being related to said measured liquid levels.

18. The method according to claim 17, wherein said algorithm employs at least one mathematical expression for computing said first data values from said measured liquid levels based on the dimensions of the tanks.