Fluid level sensing and control system

• US 6,595,051 B1
• Filed: 08/24/2001
• Issued: 07/22/2003
• Est. Priority Date: 06/08/2000
• Status: Active Grant

• Current Assignee: Sje-Rhombus
• Original Assignee: Chandler Systems, Inc.
• Inventors: Chandler, William D. Jr.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): WILSON, KATINA M
• Application Number:
  US09/939,468
• Time in Patent Office: 697 Days
• Field of Search: 737/14, 737/15, 737/23, 737/44, 737/45, 732/90.R, 732/99, 733/01, 200/83.J, 200/83.F, 200/83.N, 200/190
• US Class Current: 73/301
• CPC Class Codes: G01F 23/161 for discrete levels G01F23/162 - G01F23/165 take precedence
• CPC Class Codes: G01F 23/185 for discrete levels
• CPC Class Codes: H01H 35/18 Switches operated by change of liquid level or of liquid density, e.g. float switch by magnet carried on a float H01H36/02
• CPC Class Codes: H01H 35/2628 by varying the relative position of switch-casing and pressure sensitive element
• CPC Class Codes: H01H 35/2657 with different switches operated at substantially different pressures

Abstract

An improved pressure activated control apparatus is provided for sensing fluid pressure and triggering one or more switches in response to the fluid pressure, as desired. The apparatus is designed to be placed within a fluid of a reservoir. The apparatus includes a first resilient member, such as a pliable rolling diaphragm or bellofram, having an outer surface exposed to the fluid and responsive to the fluid pressure. The pressure activated control apparatus includes a second resilient member, such as a spring with a chosen spring constant, k, that provides a biasing force against the diaphragm that is opposite the fluid pressure. A transducer is operative to monitor changes in pressure of gases within the apparatus causes by movement of the diaphragm. A controller is responsive to the transducer and selectable fluid level thresholds to activate pumps and/or valves for adjusting the level of the fluid in the reservoir.

Claims

1. A fluid level sensing and control system comprising:

a housing, wherein the housing includes a cavity therein and a first and a second opening to the cavity;

a diaphragm in sealing engagement with the first opening, wherein portions of the diaphragm are operative responsive to a pressure from a liquid disposed outside the cavity to move inwardly with respect to the first opening to thereby decrease the volume of the cavity;

a biasing member in operative connection between the housing and the diaphragm, wherein the biasing member is operative to urge the portions of the diaphragm to move outwardly with respect to the first opening to thereby increase the volume of the cavity;

a transducer in fluid communication with the second opening, wherein the transducer is operative responsive to a pressure in the cavity to produce an electrical signal that is representative of a depth level of the liquid;

a controller device in operative connection with the transducer, wherein the controller device includes a depth range selection device that is configurable by an operator to select one of a plurality of depth ranges, wherein the controller device is operative responsive to the selected one of the depth ranges and the electrical signal to determine a fraction of the depth range that corresponds to the depth level of the liquid.

2. The system according to claim 1, further comprising:

a reservoir filled with the liquid, wherein the housing is positioned within the liquid adjacent a bottom of the reservoir, wherein the transducer is positioned outside of the liquid.

3. The system according to claim 2, further comprising at least one pump in operative connection with the controller device, wherein the pump is operative to change the amount of the liquid in the reservoir, wherein the controller device is operative to cause the pump to operate responsive to the determined fraction of the depth range.

4. The system according to claim 2, further comprising at least one valve in operative connection with the controller device, wherein the valve is operative to change the amount of the liquid in the reservoir, wherein the controller device is operative to cause the valve to operate responsive to the determined fraction of the depth range.

5. The system according to claim 2, further comprising an alarm device in operative connection with the controller device, wherein the controller device is operative to cause the alarm to emit an alarm signal responsive to the determined fraction of the depth range.

6. The system according to claim 1, further comprising a hollow tube between the transducer and the second opening.

7. The system according to claim 1, wherein the controller device includes at least one level selection device that is configurable by an operator to select one of a plurality of depth level thresholds, wherein the controller device is operative to trigger at least one switch responsive to the selected one of the depth level thresholds and the determined fraction of the depth range.

8. The system according to claim 7, further comprising at least one display device in operative connection with the controller, wherein the controller is operative to output through the at least one display device a visual representation of the determined fraction of the depth range.

9. The system according to claim 8, wherein the controller is operative to output through the at least one display device a visual representation of the selected one of the depth ranges.

10. The system according to claim 9, wherein the controller is operative to output through the at least one display device a visual representation of which ones of the plurality of switches have been triggered by the controller.

11. The system according to claim 10, wherein the plurality of depth level thresholds correspond to percentages of the selected one of the depth ranges.

12. The system according to claim 7, wherein the controller device includes at least one time lag delay switch selection device that is configurable by an operator to select one of a plurality of time lag delays, wherein the controller is operative to trigger the switch responsive to the determined fluid level continuously breaching the selected one of the fluid level thresholds for an amount of time that corresponds to the selected one of the lag delays.

13. The system according to claim 1 wherein the biasing member includes a spring mounted to the housing within the cavity, wherein the spring is positioned to urge the portions of the diaphragm outwardly with respect to the cavity.

14. A fluid level sensing and control system comprising:

a housing, wherein the housing includes a cavity and at least one opening to the cavity;

a diaphragm in sealing engagement with the opening;

a biasing member disposed within the cavity, wherein portions of the diaphragm are operative to move inwardly and outwardly with respect to the cavity responsive to the opposed pressures of the biasing member and a liquid disposed outside the cavity;

a transducer in operative connection with the diaphragm, wherein the transducer is operative responsive to movement of the diaphragm to produce an electrical signal representative of the depth level of the liquid adjacent the diaphragm;

at least one switch;

a controller device in operative connection with the transducer and the switch, wherein the controller device includes at least one depth level threshold selection device that is configurable by an operator to select one of a plurality of depth level thresholds, wherein the controller device is operative to change an electrical condition of the at least one switch responsive to the electrical signal and the selected one of the depth level thresholds; and

a compression chamber disposed within the cavity, wherein the compression chamber includes a generally sealed bore with a compressible fluid therein, wherein responsive to movement of the diaphragm an internal volume of the bore is changed, and wherein the transducer is disposed within the housing and is in fluid communication with the internal volume of the bore, wherein the transducer produces the electrical signals responsive to pressure of the compressible fluid within the bore.

15. The system according to claim 14, wherein the compression chamber includes a piston, wherein the piston is in operative connection with the diaphragm, wherein the piston is operative to move within the bore to increase and decrease the internal volume of the bore responsive to the movement of the diaphragm.

16. The system according to claim 14, wherein the controller device includes a depth range selection device that is configurable by an operator to select at least one of a plurality of depth ranges, wherein the controller device is operative responsive to the selected one of the depth ranges and the electrical signal to determine a fraction of the depth range that corresponds to the depth level of the liquid, wherein the depth level thresholds correspond to percentages of the selected one of the depth ranges, wherein the controller is operative to change the electrical condition of the at least one switch responsive to the determined fraction of the depth range breaching the selected one of the depth level thresholds.

17. A method comprising:

a) enabling an operator to select one of a plurality of different depth ranges for fluid in a reservoir;

b) enabling an operator to select at least one of a plurality of depth level thresholds, wherein the depth level thresholds correspond to fractions of the selected one of the depth ranges;

c) generating electrical signals responsive to a pressure of a gas within a cavity of a pressure responsive device, wherein the pressure responsive device is adjacent the bottom of the reservoir, wherein the pressure responsive device includes a diaphragm between the fluid and the gas, wherein the pressure responsive device includes a biasing member acting on the diaphragm which opposes the inward movement of the diaphragm caused by a pressure of the fluid acting on the diaphragm;

d) determining a fraction of the selected one of the depth ranges that corresponds to the depth level of the fluid in the reservoir responsive to the electrical signals and the selected one of the depth ranges;

e) determining that the determined fraction of the selected one of the depth ranges has breached the selected one of the depth level thresholds; and

f) causing a depth of the liquid within the reservoir to change.

18. The method according to claim 17, wherein step f) includes operating a pump.

19. The method according to claim 17 further comprising:

g) producing a visual reading that is indicative of the determined fraction of the selected depth range.

20. A fluid level sensing and control system comprising:

a housing, wherein the housing includes a cavity and at least one opening to the cavity;

a diaphragm in sealing engagement with the opening;

a biasing member in operative connection with the diaphragm, wherein portions of the diaphragm are operative to move inwardly and outwardly with respect to the cavity responsive to the opposed pressures of the biasing member and a fluid disposed outside the cavity;

a transducer in operative connection with the diaphragm, wherein the transducer is operative to produce an electrical signal representative of a current depth level of the fluid responsive to the displacement of the diaphragm with respect to the cavity;

at least one switch;

a controller device in operative connection with the transducer and the switch, wherein the controller device includes at least one input device that is operative to receive an input by an operator of at least one depth level threshold, wherein the at least one input device is further operative to receive an input by an operator of a desired depth level for the fluid, wherein the controller device is operative to determine a fractional relationship between the received desired depth level for the fluid and the current depth level of the fluid responsive to the electrical signals and the received desired depth level for the fluid, wherein the controller device is operative to control the at least one switch responsive to the determined fractional relationship breaching the received at least one depth level threshold.

21. The system according to claim 20, further comprising a reservoir and a pump in operative connection with the reservoir, wherein the reservoir includes the fluid therein, wherein the pump is operative to cause the current depth level of the fluid within the reservoir to change, wherein the switch is operative to control the operation of the pump responsive to the controller device.

22. The system according to claim 20, wherein the received at least one depth level threshold corresponds to a fraction.

23. The system according to claim 20, wherein the received at least one depth level threshold corresponds to a percentage.

24. A method comprising:

a) receiving an input representative of a desired depth level for a fluid in a reservoir;

b) receiving an input representative of at least one depth level threshold;

c) generating electrical signals responsive to a pressure responsive device disposed in the fluid;

d) determining a fractional relationship between the received desired depth level of the fluid and a current depth level of the fluid in the reservoir responsive to the electrical signals and the received desired depth level for the fluid; and

e) determining whether the determined fractional relationship has breached the received at least one depth level threshold.

25. The method according to claim 24, wherein when the fractional relationship is determined to breach the at least one depth level threshold, further comprising:

f) causing a depth of the fluid within the reservoir to change.

26. The method according to claim 24, wherein when the fractional relationship is determined to breach the at least one depth level threshold, further comprising:

f) outputting an alarm signal.

27. The method according to claim 24, wherein in step (b) the at least one depth level threshold corresponds to a fraction.

28. The method according to claim 24, wherein in step (b) the at least one depth level threshold corresponds to a percentage.