This invention relates to liquid level gauges, and more particularly to a liquid level gauge having a magnetic float that moves in response to a change in liquid level.
U.S. Pat. No. 3,815,416 to Dean et al. discloses a prior art apparatus for indicating the level of liquid in a tank car. The apparatus includes a float encircling a tube extending down into the tank. The float is magnetically coupled to a gauging rod which bears indicia representing the level of liquid in the tank. The gauging rod is normally retained inside the tube via an upper cover removably secured to the tank opening. When it is desirous to check the liquid level within the tank, the cover is removed and the gauge rod is manually raised until it magnetically couples with the float. Depending on the liquid level, the length of the gauge rod extending out of the tank will change. The user can ascertain the level in the tank by the visible indicia located on the rod. The apparatus also has a mechanism for automatically visually and audibly alerting the user when the level has reached a particular level, such as a near full condition when the tank is being filled. This mechanism includes a tower and a series of reed switches mounted on the tank above the rod opening. A magnet attached to the top of the rod moves past the reed switches to serially actuate them as the tank is filled.
Although such systems are adequate for their intended purpose, the sliding connection between the float and support tube can become worn, resulting in vibration or rattling between the support tube and the float when movement of the fluid in the tank may occur, such as during transportation of the tank and/or varying the fill level of the tank during use. Such interaction not only causes undesirable noise, but can lead to inaccurate measurement results and mechanical failure of the liquid level apparatus. It would therefore be desirable to overcome one or more disadvantages associated with prior art liquid level devices.
In accordance with one aspect of the invention, a liquid level gauge for determining the level of liquid within a container includes a mounting head adapted for connection to the container, and a sensor assembly adapted to extend into the container from the mounting head. The sensor assembly comprises a support tube extending downwardly from the mounting head; a gauge rod positioned in the support tube for selective movement out of the tank for visually determining the liquid level; a first magnet connected to the gauge rod; and a float assembly that slides along the support tube. The float assembly includes a float surrounding the support tube for sliding therealong in response to a change in liquid level; a second magnet for selective coupling to the first magnet so that the gauge rod and float are selectively coupled together; at least a first bearing positioned in the float and surrounding the support tube for sliding movement of the float therealong in response to change in liquid level; and at least a first support ring positioned at least adjacent to the first bearing to prevent the first bearing from becoming dislodged from the float.
In accordance with a further aspect of the invention, a float assembly for use in a liquid level gauge having a vertical support tube that extends into a tank for measuring a level of liquid therein comprises a float adapted to surround the vertical support tube for sliding movement therealong in response to a change in liquid level within the tank, the float having a central axis that is adapted to be coincident with a longitudinal axis of the vertical support tube; a central tube extending through the float and being coincident with the central axis thereof, the central tube having a wall with an outer surface and an inner surface defining a central bore that is adapted to surround the support tube; first and second annular projections formed at first and second locations on the central tube, the annular projections extending generally radially inwardly from an inner surface of the central bore; first and second support rings located within the central bore and retained between the annular projections; and a first bearing having a first opening for slidably receiving the support tube and being positioned in the central bore between the first and second support rings to thereby retain the first bearing between the first and second annular projections.
The following detailed description of the preferred embodiments of the present invention will be best understood when considered in conjunction with the accompanying drawings, wherein like designations denote like elements throughout the drawings, and wherein:
It is noted that the drawings are intended to depict only exemplary embodiments of the invention and therefore should not be considered as limiting the scope thereof. It is further noted that the drawings are not necessarily to scale. The invention will now be described in greater detail with reference to the accompanying drawings.
Referring now to the drawings, and to
The gauge 10 preferably includes a mounting head assembly 16 and an elongate sensing probe assembly 18 connected to the mounting head assembly 16 and extending downwardly therefrom into the tank 12.
The sensing probe assembly 18 preferably senses liquid level in a linear direction and, in accordance with one preferred embodiment of the invention, includes an outer support tube 20 with an upper end 22 that extends into the mounting head assembly 16 and a lower end 24 that terminates at a support member 26 located at or near the bottom of the tank 12. A magnetic float assembly 28 is preferably spherically-shaped and includes a central tube 30 with a central bore 31 that is sized to receive the support tube 20 so that the float slides freely therealong. An inner gauge rod 32 is located within the outer support tube 20 and has an upper end 34 that also extends through the mounting head assembly 16 and a lower end 36 fitted with a magnet 35. The support member 26 serves to both seal the support tube 20 from the contents of the tank 12 and provide a lower stop for the gauge rod 32 when the gauge rod is in the rest position. The outer support tube 18 and inner sensor tube 30 are preferably constructed of non-magnetic materials such as plastic, aluminum, composites, and so on. However, it will be understood that any suitable material can be used as long as the components do not interfere with selective magnetic coupling between the gauge rod 32 and the magnetic float assembly 28.
As shown in
If desired, an electronic sensor board (not shown) can be provided for electronically determining liquid level within the tank 12, as described in copending provisional application No. 61/876,078 filed on Sep. 10, 2013 (now U.S. application Ser. No. 14/482,573 filed on Sep. 10, 2014, the disclosures of which are hereby incorporated by reference.
Referring now to
In order to install the upper bearing 60, and as best shown in
Likewise, in order to install the lower bearing 62 in the tube 30, a first lower annular groove/projection or crimp 68 is formed in the lower portion of the central tube 30. The inner diameter of the first lower annular projection 68 is less than the outer diameter of the lower annular bearing 62 such that when the bearing is inserted in the tube, it is supported by the first lower annular projection 68. A second lower annular groove/projection or crimp 70 is then formed in the tube 30 above the lower bearing 62 to thereby secure the lower bearing within the lower portion of the tube.
The upper and lower bearings 60, 62 are preferably constructed of a low friction material, such as nylon, brass, PTFE, and so on, with a central bore 72 thereof surrounding the outer support tube 20 (
A magnet assembly 74 is connected to the lower end of the central tube 30 and includes a lower cup-shaped support 76, an annular magnet 78 received within the cup-shaped support 76, and an upper cover 80 positioned over the magnet 78 within the support 76. Tabs 82 are located around the perimeter of the support 76 and are bent inwardly over the upper cover 80 to thereby secure the magnet within the support 76. The support 76 is in turn connected to the lower end of the central tube 30 by well-known connection means, such as soldering, welding, adhesive bonding, mechanical fastening, and so on. The magnet 78 can be magnetically coupled with the magnet 35 attached to the gauge rod 32 so that, when the cap 84 of the head assembly 16 is removed, the gauge rod 32 can be manually pulled upwardly until it is magnetically coupled with the float. The gauge rod 32 has a scale (not shown) so that the level of the liquid within the tank 12 can be visually observed in a well-known manner.
The magnet is preferably magnetized on its outer and inner faces such that magnetic flux lines of force are directed perpendicular with respect to the longitudinal extent of the magnet and toward the center of the central tube 30 of the float 28. However, it will be understood that the polarity of the magnets can be reversed and/or the direction of the magnetic flux can be oriented differently without departing from the spirit and scope of the invention.
The components of the float assembly 28 are preferably constructed of rigid materials, such as stainless steel, aluminum or other metals, but can be constructed of other materials, such as closed-cell nitrile material, rubber, plastics, and so on, without departing from the spirit and scope of the invention. It will be understood that the shapes of the float, support tube 20, central tube 30, the mounting head assembly, and so on, are given by way of example only, as other suitable shapes, such as square, triangular, and so on, can be used without departing from the spirit and scope of the invention.
As shown in
In use, when the end cap 84 is installed on the cover 86 as shown in
Referring now to
Referring now to
Each dampener assembly is similar in construction and includes a collar 124 slidably mounted on the support tube 20, a first spring seat 126 mounted at a fixed location with respect to the support tube 20, a second spring seat 25 slidably mounted on the support tube 20 and located within the collar 124, and a compression spring 128 sandwiched between the first and second spring seats 126 and 125, respectively. slidable collar and the fixed spring seat. The compression spring 128 is preferably connected to the spring seat 126 through welding or other connection means. The collar 124 can also be fixedly connected to the spring 128 through welding or other connecting means. However, it is preferred that the spring is free-floating between the first and second spring seats to prevent damage and possible breakage of the spring and other components of the dampener assembly. This is an advantage over prior art welded components since the spring is subjected to undesired stress during operation and can break.
The collar 124 is generally annular in shape with a first wall 130 that contacts the second spring seat 125 which in turn contacts the spring 128 on one side thereof. The other side of the first wall 130 faces the float assembly 28 for contact therewith. A second wall 132 extends axially away from the first wall to form a cup-shaped interior for receiving the second spring seat 125 and one end of the spring 128. Likewise, the first and second spring seats 126, 125 are annular in shape with a first wall 134 that contacts the spring 128 and a second wall 136 that extends axially therefrom to form a cup-shaped interior for receiving the opposite ends of the spring 128.
It will be understood that the term “preferably” as used throughout the specification refers to one or more exemplary embodiments of the invention and therefore is not to be interpreted in any limiting sense. It will be further understood that the term “connect” and its derivatives refers to two or more parts capable of being attached together either directly or indirectly through one or more intermediate members. In addition, terms of orientation and/or position as may be used throughout the specification denote relative, rather than absolute, orientations and/or positions.
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. By way of example, the mounting head is not limited to the flange-type arrangement as shown and described but can be formed with threads or other known mounting means for connecting the gauge to the container without departing from the spirit and scope of the invention. It will be understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
This application claims the benefit of U.S. Provisional Application No. 61/918,662 filed on Dec. 20, 2013, the disclosure of which is hereby incorporated by reference.
Number | Date | Country | |
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61918662 | Dec 2013 | US |