Liquid level gauge

• US 6,089,086 A
• Filed: 07/02/1998
• Issued: 07/18/2000
• Est. Priority Date: 08/26/1997
• Status: Expired due to Term

• Current Assignee: Rochester Gauges Incorporated
• Original Assignee: Rochester Gauges Incorporated
• Inventors: Dudley, Amber N., Swindler, Danny E., Ross, Herbert G. Jr.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): WORTH, WILLIE M
• Application Number:
  US09/109,437
• Time in Patent Office: 747 Days
• Field of Search: 73/305, 73/317, 73/DIG. 5, 116/229
• US Class Current: 73/317
• CPC Class Codes: F17C 2250/0413 with floats
• CPC Class Codes: G01F 23/34 using mechanically actuated indicating means G01F23/38 takes precedence
• CPC Class Codes: G01F 23/38 using magnetically actuated indicating means
• CPC Class Codes: Y10S 73/05 Liquid levels with magnetic transmission

Abstract

A float-type liquid level gauge is provided for measuring the level of a liquid such as LPG within a horizontally oriented cylindrical tank (228). The gauge includes a movable pivot arm (212) supporting a float arm assembly (225) and coupled by gears (207, 214) to a magnet shaft (206, 208) and magnet (210) mounted in a rigid support arm (204) through a sideways-securing shaft channel(209). The support arm is connected to the lower side of a gauge head (202) and the magnet extends into a passage (52) in the gauge head so as to be magnetically coupled to a level indicating dial (226) provided on the upper side of the gauge head. The lower portion (302) of the support arm is angled and offset with respect to a longitudinal axis (265) such that a high ratio can be obtained between the gears while still permitting the components of the gauge to pass through the opening of a standard pressure fitting (234).

Claims

1. A gauge support assembly for use with a magnetically driven indicating dial assembly and a float arm assembly to measure the level of a liquid inside a horizontally oriented cylindrical pressure vessel having a diameter within the range of about 24 inches to about 42 inches, said gauge support assembly comprising:

a) a gauge head having a lower portion defining a passage formed on its lower surface and a dial assembly mounting portion formed on its upper surface;

b) a support arm having an longitudinal axis, an upper end connected to said lower portion of said gauge head, a pivot arm attachment portion being located at a first distance from said upper end, and a middle portion extending between said upper end and said pivot arm attachment portion;

said middle portion defining a sideways-securing shaft channel extending between said upper end and said pivot arm attachment portion along said longitudinal axis;

c) a magnet drive shaft assembly rotatably mounted in said shaft passage and having a magnet holder located at an upper end and a pinion gear located at a distance from said upper end;

said upper end of said shaft assembly extending beyond said upper end of said support arm and positioning said magnet holder within said passage of said gauge head;

d) a magnet being secured to said magnet holder of said magnet drive shaft;

e) a pivot arm being pivotally connected to said pivot arm attachment portion of said support arm, and having a spur gear portion and a float arm attachment portion;

said spur gear portion including a plurality of gear teeth arranged in an arc around a center point, said teeth having a maximum radius from said center point;

said float arm attachment portion having at least one fastening feature for securely connecting a float arm assembly to said pivot arm;

said spur gear portion operably engaging said pinion gear to impart rotational motion to said shaft, said magnet holder and said magnet relative to said support arm and said gauge head upon the angular movement of said pivot arm relative to said support arm.

2. A gauge support assembly according to claim 1, wherein said gauge head is adapted for screw-in connection to an internally threaded pressure fitting.

3. A gauge support assembly according to claim 2, wherein said gauge head is adapted for snap-on connection of a magnetically coupled indicator dial.

4. A gauge support assembly according to claim 2, wherein said gauge head is adapted for screw-on connection of a magnetically coupled indicator dial.

5. A gauge support assembly according to claim 2, wherein all of the constituent components of said support assembly except said gauge head can pass through a circular passage having a diameter within the range from about 1.1 inches to about 1.3 inches.

6. A gauge support assembly according to claim 2, wherein all of the constituent components of said support assembly except said gauge head can pass through an internally threaded pressure fitting having a passage with a diameter of about 1.13 inches.

7. A gauge support assembly according to claim 2, wherein the gear ratio between said spur gear portion of said pivot arm and said pinion gear is at least 2:

1.

8. A gauge support assembly according to claim 7, wherein the gear ratio between said spur gear portion of said pivot arm and said pinion gear is within the range of 2.0:

1 to about 2.5;

1.

9. A gauge support assembly according to claim 7, wherein said spur gear portion of said pivot arm is formed of a molded plastic material.

10. A gauge support assembly according to claim 7, wherein said float arm attachment portion of said pivot arm is adapted for snap-in connection of a float arm assembly.

11. A gauge support assembly according to claim 10, wherein said attachment portion has a first wire guide portion for snap-in connection and alignment of a first portion of said float arm assembly along a first line and a second wire guide portion for snap-in connection and alignment of a second portion of said float arm assembly along a second line, said first and second lines being non-collinear.

12. A gauge support assembly according to claim 7, wherein said pivot arm is a unitary component formed of a molded plastic material.

13. A gauge support assembly according to claim 12, wherein said plastic material is acetal plastic.

14. A gauge support assembly according to claim 7, wherein said pivot arm further comprises an integral internal float stop adapted to interfit with a keyway formed on said support arm such that the range of motion of the pivot arm relative to the support arm is restricted to a predetermined arc.

15. A gauge support assembly according to claim 7, wherein said magnet drive shaft assembly is a unitary component formed of a molded plastic material.

16. A gauge support assembly according to claim 7, wherein said magnet drive shaft assembly comprises an upper drive shaft including said magnet holder and a lower drive shaft including said pinion gear.

17. A gauge support assembly according to claim 16, wherein said magnet holder is integrally formed with said upper drive shaft and said pinion gear is integrally formed with said lower drive shaft.

18. A gauge support assembly according to claim 17, wherein said magnet holder is adapted for snap-fit connection of said magnet.

19. A gauge support assembly according to claim 1, wherein said spur gear portion of said pivot arm comprises a plurality of gear teeth arranged in an arc about a center which is laterally offset with respect to the center of the shortest lateral side of the pivot arm, said arc of teeth having an overall angular extent of less than about 180°

.

20. A gauge support assembly according to claim 19, wherein said pivot arm attachment portion of said support arm has, when viewed from the front side, a leftmost extent and a rightmost extent defining a lateral width therebetween, and said attachment portion defines an axle passage for receiving a pivot arm pivot axle;

said axle passage defining a pivot axis for said pivot arm;

said pivot axis being front laterally offset on said attachment portion such that a first distance from the pivot axis to one of said leftmost extent and said rightmost extent is greater than a second distance to another of said leftmost extent and said rightmost extent.

21. A gauge support assembly according to claim 20, wherein said teeth of said spur gear portion have a maximum radial distance from said arc center which is greater than 0.5 times the lateral width, measured through the pivot axis, of said pivot arm attachment portion of said support arm.

22. A gauge support assembly according to claim 21, wherein said teeth of said spur gear portion have a maximum radial distance from said arc center which is greater than about 0.56 inches and a maximum lateral width less than about 1.13 inches.

23. A gauge support assembly according to claim 1, wherein said support arm is a unitary component formed of a molded plastic material.

24. A gauge support assembly according to claim 23, wherein plastic material is acetyl plastic.

25. A gauge support assembly according to claim 1, wherein said support arm further comprises a support member formed on the upper end of said support arm and adapted to fit within said passage on the lower side of said gauge head.

26. A gauge support assembly according to claim 25, wherein said support member of said support arm comprises a generally cylindrical boss formed around said longitudinal axis and having at least one slot formed through the side of said boss.

27. A gauge support assembly according to claim 25, wherein said support member of said support arm comprises a continuous cylindrical boss formed around said longitudinal axis.

28. A gauge support assembly according to claim 1, wherein said gauge head is adapted for bolted connection to a flanged pressure fitting.

29. A gauge support assembly according to claim 28, wherein said gauge head is adapted for snap-on connection of a magnetically coupled indicator dial.

30. A gauge support assembly according to claim 28, wherein said gauge head is adapted for screw-on connection of a magnetically coupled indicator dial.

31. A gauge sub-assembly for use with a magnetically-coupled indicator dial for measuring the level of a liquid inside a horizontally oriented cylindrical pressure vessel having a diameter within the range of about 24 inches to about 42 inches, said gauge sub-assembly comprising:

a gauge support assembly according to claim 1; and

a float arm assembly connected to said pivot arm.

32. The gauge sub-assembly of claim 31, wherein said float arm assembly further comprises:

a float buoyant in LPG; and

a float arm including a z-shaped center section, a float arm section and a counterweight section;

said center section comprising a first, second and third straight sections separated by a first and second 90°

angles and being adapted to interfit with the attachment portion of said pivot arm;

said float arm section extending between said center section and said float; and

said counterweight section extending between said center section and a counterweight.

33. The gauge sub-assembly of claim 32, wherein said float arm section further comprises:

a curved section extending from said float, said curved section constituting, when viewed from the side, a curve having a radius of curvature of at least one inch, and being connected to a first straight section, said first straight section having a length within the range of about 5 inches to about 6 inches and being connected to a first bend, said first bend being connected to a second straight section having a length within the range from about 3 inches to about 21 inches, said second straight section being bounded on a first side by said first bend and bounded on a second side by a second bend, said second bend being connected to said first straight section of said z-shaped center section, said second straight section forming, when viewed from the front, an angle within the range of about 21°

to about 0°

with respect to a line constituting an extension of said first straight section of the z-shaped center section connected to said second bend.

34. The gauge sub-assembly of claim 32, wherein said counterweight arm section further comprises:

a third straight section constituting an extension of said third straight section of the z-shaped center section, said third straight section having a length within the range of about 2 inches to about 3 inches, measured from the last 90°

bend in said center section, and being connected to a third bend, said third bend being connected to a tail section for attachment of the counterweight, said tail section forming, when viewed from the front, an angle of about 7°

with a line constituting an extension of said third straight segment; and

a counterweight attached to said third straight segment.

35. A gauge for measuring the level of a liquid inside a horizontally oriented cylindrical pressure vessel having a diameter within the range of about 24 inches to about 42 inches, said gauge comprising:

a gauge sub-assembly according to claim 31; and

a magnetically driven indicating dial.

36. The gauge of claim 35, wherein said indicating dial is adapted for snap-on connection to said gauge head.

37. The gauge of claim 36, wherein said dial produces a visual indication of the position of the magnet.

38. The gauge of claim 37, wherein said dial also produces a non-visual signal indicating the position of the magnet, said non-visual signal suitable for remote sensing.

39. The gauge of claim 35, wherein said indicating dial is adapted for screw-on connection to said gauge head.

40. A gauge for measuring the level of LPG inside a horizontally oriented cylindrical storage tank having a diameter within the range of about 24 inches to about 42 inches, said gauge comprising:

a) a gauge head having a lower portion defining a passage formed on its lower surface and a dial assembly mounting portion formed on its upper surface;

b) a magnetically coupled indicator dial attached to said dial assembly mounting portion of said gauge head;

c) a support arm having an longitudinal axis, an upper end connected to said lower portion of said gauge head, a pivot arm attachment portion being located at a first distance from said upper end, and a middle portion extending between said upper end and said float arm attachment portion, said first distance being within the range of about 10.5 inches to about 14 inches;

said middle portion defining a sideways-securing shaft channel extending between said upper end and said pivot arm attachment portion along said longitudinal axis;

d) a magnet drive shaft assembly rotatably mounted in said shaft passage and having a magnet holder located at an upper end and a pinion gear located at a distance from said upper end;

said upper end of said shaft extending beyond said upper end of said support arm and positioning said magnet holder within said passage of said gauge head;

e) a magnet being secured to said magnet holder of said magnet drive shaft assembly;

f) a pivot arm being pivotally connected to said pivot arm attachment portion of said support arm, and having a spur gear portion and a float arm attachment portion;

said spur gear portion including a plurality of gear teeth arranged in an arc around a center point and having a maximum radial distance from said center point;

said float arm attachment portion having at least one fastening feature for securely connecting a float arm assembly to said pivot arm;

g) a float arm assembly including a float buoyant in LPG and a float arm including a z-shaped center section, a float arm section and a counterweight section;

said center section comprising a first, second and third straight sections separated by a first and second 90°

angles and being adapted to interfit with the attachment features of said pivot arm;

said float arm section extending between said center section and said float and further comprising a curved section extending from said float, said curved section constituting, when viewed from the side, a curve having a radius of curvature of at least one inch, and being connected to a first straight section, said first straight section having a length within the range of about 5 inches to about 6 inches and being connected to a first bend, said first bend being connected to a second straight section having a length within the range from about 3 inches to about 21 inches, said second straight section being bounded on a first side by said first bend and bounded on a second side by a second bend, said second bend being connected to said first straight section of said z-shaped center section, said second straight section forming, when viewed from the front, an angle within the range of about 21°

to about 0°

with respect to a line constituting an extension of said first straight section of the z-shaped center section connected to said second bend;

said counterweight section extending between said center section and a counterweight and further comprising a third straight section constituting an extension of said third straight section of the z-shaped center section, said third straight section having a length within the range of about 2 inches to about 3 inches, measured from the last 90°

bend in said center section, and being connected to a third bend, said third bend being connected to a tail section for attachment of the counterweight, said tail section forming, when viewed from the front, an angle of about 7°

with a line constituting

an extension of said third straight segment,

and a counterweight attached to said third straight segment;

wherein said spur gear portion of said pivot arm engages said pinion gear to impart rotational motion to said shaft, said magnet holder and said magnet relative to said support arm and said gauge head upon angular movement of said pivot arm relative to said support arm.

41. A method of assembling a gauge support assembly for use with a magnetically driven indicating dial assembly and a float arm assembly, said method comprising the steps of:

a) providing a support arm having a longitudinal axis, an upper end having a generally cylindrical support member projecting therefrom along said longitudinal axis and having a passage formed therethrough along said longitudinal axis, a pivot arm attachment portion being located at a first distance from said upper end, and a middle portion extending between said upper end and said pivot arm attachment portion;

said middle portion defining a sideways-securing shaft channel extending between said support member and said pivot arm attachment portion along said longitudinal axis;

said sideways-securing shaft channel having a plurality of securing members formed therealong;

said pivot arm attachment portion being, when viewed from the front side, front-laterally offset with respect to said longitudinal axis and having a leftmost extent and a rightmost extent defining a lateral width therebetween, and said attachment portion defining an axle passage for receiving a pivot arm pivot axle;

said axle passage defining a pivot axis for said pivot arm pivot axle;

said pivot axis being front laterally offset on said attachment portion such that a first distance from the pivot axis to one of said leftmost extent and said rightmost extent is greater than a second distance to the other of said leftmost extent and said rightmost extent such that said pivot axis intersects said longitudinal axis of said support arm;

b) providing a magnet drive shaft assembly;

c) inserting at least a portion of said drive shaft assembly downwardly and at an angle with respect to said longitudinal axis through said passage in said support member such that said shaft portion is positioned adjacent to said securing members of said shaft channel but on the opposite side of said securing members from said longitudinal axis,

d) positioning said shaft portion longitudinally at a desired location with respect to said channel; and

e) securing said shaft portion in said shaft channel by moving it sideways into said shaft channel toward the longitudinal axis until it is secured by said securing members.