Abstract:
A device measures the high and low fluid levels of a fluid body. A housing has a shaft with a buoyant weight, the shaft protruding through a cap on the housing&#39;s top and capable of sliding through the cap. A first ring encompasses the shaft and is initially positioned immediately below the cap, while a second ring is positioned immediately above the cap. As fluid enters the housing, the shaft rises in lockstep with the fluid level causing the first ring to be pushed downwardly on the shaft and when the fluid level falls, the shaft falls causing the second ring to be pushed upwardly along the shaft. The distance between the rings is the amount of fluid level variation. A debris tube attached to the housing measures the upper limit of fluid level. Subtracting the amount of variation from this upper limit yields the lower fluid level limit.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a fluid level measurement device that can easily and accurately measure both the high fluid level and the low fluid level for a body of fluid over a period of time. 
   2. Background of the Prior Art 
   The levels of most of the earth&#39;s navigable bodies of water are not constant but fluctuate between a low level or a low tide and a high level or a high tide. The variations in the levels are generated partly by the unhomogeneous gravitational fields of the moon, the Sun, and the planets of the solar system and partly by the deformation of the Earth. A second component that acts on tides are the gravitational effects of the water masses in oceans and seas moved by these water forces and the deformations of the Earth-due to weight of the water masses. As the tide levels are critical to a variety of interests, including navigation, boundaries, environmental assessments, and sea level change, obtaining accurate tide levels is critical. At least as early as 1807, when Thomas Jefferson created the Coast Survey to map and chart the country&#39;s coasts and harbors, there was a recognized need to accurately measure and record the tidal levels of our seas and oceans. 
   Today, the need for tidal measurement continues to be of great importance. Modern tidal measurement needs are not restricted to harbors and other shipping channels, but are necessary along the entire coast line of a body of water. One of the simplest methods to measure tide levels at a given location, is to have a person at the desired location with an appropriate measuring rod that is positioned against a fixed reference point, with the person taking readings at regular intervals. The problem with this method is that there is a substantial amount of time between high tide and low tide resulting in an underutilization of human capital. Additionally, many tidal measurements are performed across multiple tidal cycles which adds to the capital inefficiency and also leads to inattention and sloppiness by the measurement personal. On the other end of the spectrum, are a plethora of electronic measurement devices that automatically measure the tide levels. The problems with such devices is that they are extremely expensive and tend to be difficult to calibrate and operate. As several hundred measurements may need to be taken along a given stretch of coastline, these devices are either extremely expensive to implement or are very slow in their goal achievement as only one or maybe a handful of such devices are purchased and moved from location to location over a relatively long time span. Additionally, such devices, due to the harsh environment in which the devices operate, tend to require frequent and oftentimes expensive repairs. 
   Accordingly, there exists a need in the art for a device that quickly and accurately measures both the high water level and the low water level at a given location without the need for a technician to be present during the measurement cycle, which device is of relatively simple design and construction and is easy to use requiring little if any calibration to use. Such a device must be highly resistant to the harsh environment in which the device operates so that repairs are kept to a minimum. 
   SUMMARY OF THE INVENTION 
   The fluid level measurement device of the present invention addresses the aforementioned needs in the art. The fluid level measurement device measures the high level mark and the low level mark within a fluid body such as an ocean. Once the fluid level measurement device is properly installed, it requires no further technician involvement until readings are retrieved. The fluid level measurement device is of relatively simple design and construction and is easy to install and calibrate for use. The fluid level measurement device is highly resistant to the harsh elemental effects found in its operating environment such that the device is subject to relatively few breakdowns during normal use. 
   The fluid level measurement device is comprised of a housing that has a first top end, a first bottom end, a hollow interior, and a first opening located proximate the bottom end for allowing the fluid to enter the hollow interior and rise therein. A cap has a second opening attached to the top end of the housing. A shaft has a base and a top such that the shaft protrudes through the second opening of the cap and is capable of sliding up and down through the second opening and such that the base of the shaft is disposed within the hollow interior and the top is located exterior of the housing. A first ring encompasses the shaft, below the cap, and is capable of sliding along the shaft, while a second ring encompasses, the shaft, above the cap, and is capable of sliding along the shaft. A tube is attached to an outer surface of the housing, the tube having a second top end, a second bottom end, a third opening located proximate the second bottom end, and an amount of debris disposed within the tube. The first ring is positioned in abutting relationship with the cap and the second ring is positioned in abutting relationship with the cap and as the fluid enters the interior of the housing and rises within the interior, the shaft rises in lockstep with the rise in the fluid level such that the cap slides the first ring downwardly along the shaft toward the base and as the fluid level within the interior falls, the cap slides the second ring upwardly along the shaft toward the top and wherein when the fluid enters the third opening of the tube and rises within the tube toward the second top, some of the debris is carried upwardly toward the top by the fluid and deposited on an inner surface of the tube when the fluid recedes. A receptacle is located at the base of the shaft and is filled with the fluid for providing a buoyant weight for the shaft. A measurement gradient is located along a portion of the shaft. A mounting system is provided for attaching the housing to a fixed structure. An upper portion of the housing is clear. The tube is clear. A measurement gradient is also located along a portion of the tube. The debris within the tube may be cork dust. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the fluid level measurement device of the present invention. 
       FIG. 2  is a perspective view of the float shaft used within the fluid level measurement device. 
       FIG. 3  is a close-up perspective view of the fluid level measurement device, with the fastening system not illustrated for clarity and brevity. 
       FIG. 4  is a sectional view of the fluid level measurement device taken along line  4 - 4  in  FIG. 3 . 
       FIG. 5  is a top plan view illustrating the mounting of the top fastening system of the fluid level measurement device. 
       FIG. 6  is a perspective view of the top fastening system of the fluid measurement device. 
       FIG. 7  is a perspective view of the bottom fastening system of the fluid level measurement device. 
   

   Similar reference numerals refer to similar parts throughout the several views of the drawings. 
   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings, it is seen that the fluid level measurement device of the present invention, generally denoted by reference numeral  10 , is comprised of a hollow tubular housing  12  having a top end  14  and a bottom end  16 , which may be capped, with an opening  18  located proximate the bottom end  16  for allowing fluid F to enter and leave the interior of the housing  12 . The housing  12  may be of monolithic construction, or, as illustrated, may be made of two or more sections, such as an upper section  20  and a lower section  22  joined together by a collar  24 , which may frictionally hold each section  20  and  22 . By utilizing a multi-sectional design, service access to the interior of the housing  12  is easy to achieve and the upper section  20  may be made from a transparent material in order to allow visual access into the interior so as to be able to take quick measurements as more fully discussed below. A cap  26  has an opening  28  and is attached, removably or otherwise, to the top end  14  of the housing  12 . A measurement shaft  30  is provided and has a top  32  and a bottom  34  with a receptacle  36  attached to the bottom  34 , such that the receptacle  36  can be filled with a fluid F. A measurement gradient  38  is located along a length of the shaft  30 . The shaft  30  is positioned such that it is partially disposed within the interior of the housing  12  with the receptacle  36  fully disposed within the housing  12 . The shaft  30  protrudes through the opening  28  of the cap  26  such that the top of the shaft  30  terminates exterior of the housing  12 . The shaft  30  is capable of sliding up and the down through the opening  28  of the cap  26 . A first ring  40  encompasses the shaft  30  and is positioned below the cap  26  while a second ring  42  encompasses the shaft  30  and is positioned above the cap  26 . Each ring  40  and  42  is capable of sliding up and down along a length of the shaft  30 . 
   The housing  12  and the shaft  30  can be made from any appropriate lightweight material such as plastic, PVC, etc. The receptacle  36  should be made from a material such that when the receptacle  36  is filled with the fluid F and the housing  12  has a level of fluid therein, the receptacle  36 , with shaft  30  attached, is slightly buoyant in the fluid F. A lightweight plastic or similar material can be used to form the receptacle  36 . The first ring  40  and second ring  42  should be made from a lightweight material that allows the rings  40  and  42  to slide along the shaft  30  with moderate force, yet not allow the rings  40  and  42  to slide simply under the force of gravity. A lightweight plastic or an open or closed cell foam or other similar material can be used to form the rings  40  and  42 . 
   A debris tube  44  is attached to an exterior surface of the housing  12  in any appropriate fashion, such as be adhesive, etc., and has a bottom end  46  and a top end  48 . An opening  50  is located on the debris tube  44  proximate its bottom end  46  for allowing the fluid F to enter therein. A measurement gradient  52  is provided on the outer surface of the housing  12  and coextends with the debris tube  44 . The debris tube  44  is clear and has an amount of debris  54  therein such as cork dust, although other types of debris work satisfactory so long as the fluid F that enters the debris tube  44  through its opening  50  can carry the debris  54  upwardly within the debris tube  44  as the fluid F rises therein. 
   The fluid level measurement device  10  is attached to a desired structure, such as a piling P, in any appropriate fashion.  FIGS. 5-7  illustrate an example of an attachment method. A bracket  56  is secured to the piling P by passing one or more screws  58  through the bracket  56  into the piling P. The bracket  56  has a shape that corresponds to the outer shape of the housing  12  for snugly receiving the housing  12  therein. A strap  60  having a quick disconnect buckle system  62  is attached to the bracket  56  and encompasses an upper portion of the housing  12  for securing the housing  12  at this upper portion. As specifically seen in  FIG. 7 , in attaching a lower portion of the housing  12  to the piling P, a sleeve  74  large enough to enclose the housing  12  and the attached debris tube  44  has a second strap  64  that is attached thereto by a first end  66 , the second strap  64  encompasses the piling P. The second end  68  of the strap  64  encompasses, via a loop member  70 , a lock pin  72  that is frictionally received within a two section receiver  76  located on the sleeve  74 . A lanyard  78  is attached to the lock pin  72 . When attachment of the lower portion of the housing  12  to the piling P is desired, the second strap  64  encompasses the piling P and the loop member  70  is placed over the lock pin  72 . The lock pin  72  is inserted into the receiver  76 . The loop member is positioned between the two sections of the receiver  76 . Accordingly, the sleeve  74  is held in place against the piling P and the housing  12  and attached debris tube  44  are received within the sleeve  74 . When detachment of the lower portion of the housing  12  from the piling P is desired, the lanyard  78  is grasped by a user and pulled upon to remove the lock pin  72  from the receiver  76 . The lock pin  72  also looses the loop member  70  attached to the second strap  64  which allows the second end  68  of the second strap  64  to fall clear and unencompass the piling P allowing the sleeve  74  to become free of the piling P and thus allowing removal of the housing  12 . 
   It is expressly understood that other attachment methods for attaching the fluid level measurement device  10  to a desired structure are possible in keeping within the scope and spirit of the present invention. 
   In order to use the fluid level measurement device  10  of the present invention, the housing  12  is attached to a desired structure in appropriate fashion. A lower portion of the housing  12  must be below the fluid line a sufficient distance so that at low tide, the fluids level within the housing  12  will be greater than the height of the receptacle  36 . Additionally, the housing  12  must be positioned so that the opening  50  on the debris tube  44  is below the fluid line at low tide. Once the housing  12  is appropriately attached, the fluid F is allowed to enter the interior of the housing  12  through the housing&#39;s opening  18  and the fluid level is allowed equalize with the fluid level exterior of the housing  12 . The first ring  40  is positioned just below the cap  26  while the second ring  42  is positioned just above the cap  26 . The cap  26  is placed onto the top  14  of the housing  12 . If necessary, the inner surface of the debris tube  44  is cleaned and the bottom of the debris tube  44  is filled with an appropriate debris  54 , such as the above mentioned cork dust. The device  10  is now ready for use for taking fluid level measurements. 
   As fluid enters the opening  50  of the debris tube  44 , the debris  54  within the debris tube floats upwardly with the rising fluid level. As the height of the fluid level peaks, some of the debris  54  within the debris tube is deposited on the inner surface of the debris tube  44 . As the fluid level recedes, some of the debris  54  remains on the inner surface of the debris tube  44  at the point of the highest fluid level. This marks the upper fluid level height and a measurement is taken via the measurement gradient  52 . Coincidentally, as the fluid level rises within the interior of the housing  12 , the receptacle  36 , by being slightly buoyant, rises with the rising fluid level. As the receptacle  36 , so does the shaft  30  which pushes upwardly through the opening  28  on the cap  26 . The cap  26  acts on the first ring  40  and pushes the first ring  40  downwardly along the shaft  30  toward the shaft&#39;s bottom  34  with upward shaft  30  movement. As the fluid level within the interior of the housing  12  falls, the receptacle  36  falls with the falling fluid level. The falling receptacle  36  causes the shaft to retract back downwardly through the opening  28  of the cap  26 . Once the receptacle  36  has fallen a sufficient distance, and thus the shaft  30  has retracted a sufficient distance down through the opening  28  of the cap  26 , the second ring  42  encounters the cap  26  and the cap  26  acts on the second ring  42  and pushes the second ring  42  upwardly toward the shaft&#39;s top  32  with downward shaft  30  movement. This system works equally well if initially after the device  10  becomes operational, the fluid level within the interior of the housing falls before rising. Once at least one full cycle of high tide and low tide have been achieved, the distance between the first ring  40  and the second ring  42  represent the height difference between the high tide and the low tide. The difference is easily measured by the measurement gradient  38  located along the shaft  30 . As the height measurement within the debris tube  44  represents the high tide level, subtracting the height difference as measured by the first ring  40  and the second ring  42  from this high tide level represents the low tide level. In order to reuse the device  10 , the housing  12  is detached from its attachment structure and reattached at its new measurement point. The debris tube  44  is cleaned, and if needed, refilled with additional debris  54 , and the rings  40  and  42  are reset to be just above and just below the cap  26  respectively. 
   While the invention has been particularly shown and described with reference to an embodiment thereof, it will be appreciated by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention.