Abstract:
The food viscometer of the present invention includes a microprocessor controlled fluid viscometer assembly contained in a housing configured for easy mounting on the upper edge of a glass or other conventional drinking utensil. Projecting from the housing of the food viscometer is a probe that is placed in the liquid contained in the liquid container. The housing adjustably engages a base assembly that permits raising and lowering of the housing to ensure that the probe is placed a predetermined depth into the liquid. The base assembly also securely engages the upper edge of the liquid container to ensure the generally vertical positioning of the probe within the liquid, and also to ensure that the probe is spaced a predetermined minimum distance from the edges of the liquid container.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to rotational viscometers for measuring the viscosity of a fluid, and in particular to a rotational viscometer for measuring the viscosity of nutritional liquids for people suffering from dysphagia. 
     Rotational viscometers for measuring the viscosity of fluids are well known, and have been used for a wide variety of applications, generally industrial in nature. However, only in recent years has attention been focused on the needs of patients suffering with the condition known as dysphagia. Dysphagia is a physical condition, usually the result of a trauma to the body, such as an accident or a stroke, that is manifested by a difficulty in swallowing. As with many other physical conditions, dysphagia may be more or less severe for different patients, and may improve or worsen over time for a particular patient. 
     Methods of measuring the severity of dysphagia for a particular patient are under development to classify accurately the degree of severity of that patient&#39;s condition for purposes of developing treatments and diets best suited to the patient&#39;s condition. Of particular interest is the development of a diet that provides nutritional foods which may be swallowed by the dysphagia patient without the risk of choking or other negative responses resulting from the patient&#39;s swallowing disorder. Presently, four fluid viscosity groupings are generally recognized to reflect the various degrees of severity of dysphagia. These four groupings are: thin; nectar like; honey like; and spoon thick. Examples of foods that fall in these categories range from broth in the thin grouping to puree in the spoon thick category. 
     As noted above, various viscometers have been used for a variety of applications in the past. However, these have not been available for easy, portable use. Further, prior art viscometers have not provided the capability to detect three break points and determine which of the four resulting zones a viscosity reading falls within, and then give a visual indication of which such zone contains the resulting reading. 
     The food viscometer of the present invention overcomes difficulties described above and affords other features and advantages heretofore not available. 
     SUMMARY OF THE INVENTION 
     The food viscometer of the present invention includes a microprocessor controlled fluid viscometer assembly contained in a housing configured for easy mounting on the upper edge of a glass or other conventional drinking utensil. Projecting from the housing of the food viscometer is a probe that is placed in the liquid contained in the liquid container. The housing adjustably engages a base assembly that permits raising and lowering of the housing to ensure that the probe is placed a predetermined depth into the liquid. The base assembly also securely engages the upper edge of the liquid container to ensure the generally vertical positioning of the probe within the liquid, and also to ensure that the probe is spaced a predetermined minimum distance from the edges of the liquid container. 
     The probe of the food viscometer may be a straw or rod, which is replaceably detachable from a clamping means on the housing. A motor in the housing spins the probe at a predetermined rate, and the microprocessor measures the electrical current used by the motor. The current used by the motor while the probe is positioned in the liquid is compared to the current used by the motor to turn the probe before placing the probe in the liquid, and the viscosity of the liquid is calculated based on this measurement. 
     It is an object of the present invention to provide a viscometer for easily and accurately determining the viscosity range of liquid foods for service to patients suffering from dysphagia. It is a further object of this invention to provide such a food viscometer that is simple to use, and controls many of the external factors that might otherwise lead to inaccurate viscosity readings. It is a further object of this invention to provide an accurate, objective measurement standard for measuring the viscosity range of liquid foods. It is also an object of this invention to reduce costs related to thickeners, packaged liquids, and errors resulting from attempts to prepare a proper diet for patients suffering from dysphagia. It is yet a further object of this invention to promote better patient hydration and nutrition, and to improve patient care and satisfaction. 
     Other objects and advantages of the invention will become apparent from the following detailed description and from the appended drawings in which like numbers have been used to describe like parts throughout the several views. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a is a perspective view of the food viscometer of the present invention; 
     FIG. 2 is a rear exploded perspective view of the food viscometer showing the base assembly in the fully extended position; 
     FIGS. 3A, 3B and 3C are front views of the food viscometer showing the food viscometer in position for engaging the upper edge of a liquid serving container, resting on the upper edge of the liquid serving container, and lowered for the probe to engage the liquid contained in the container, respectively; 
     FIG. 4 is a bottom view of the food viscometer taken along line 4--4 of FIG. 3A; 
     FIG. 5 is a side view of the base assembly engaging the upper edge of the liquid serving container; 
     FIG. 6 is a section view of the base assembly taken along line 6--6 of FIG. 3B; and 
     FIGS. 7A and 7B are first and second portions, respectively, of an electrical schematic of the food viscometer. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to the drawings, and in particular to FIG. 1, the food viscometer of the present invention is generally indicated by reference numeral 10. Food viscometer 10 includes a probe 12 attached thereto to be immersed a predetermined distance, preferably approximately two inches, into a fluid F contained in a cup or other beverage container C. 
     Referring to FIG. 2, food viscometer 10 includes a rear panel 14, a circuit board 16, and a battery 18. Power may also be provided from an AC adapter, not shown. Housing 20 also contains spring lever 22 engaging ratchet teeth 24 of ratchet tooth assemblies 26 of right and left columns 28, 30, respectively. A motor 32 is contained within motor cover 34. Motor 32 is releasably linked to probe 12 by conventional means. Columns 28, 30 support and are a part of adjustable base assembly 36, which also includes base member 38. 
     Referring again to FIG. 1, front panel 40 includes projecting therefrom a test button 42 and a position button 44. Several signal lights are also displayed on front panel 40, including a wait status indicator 46 and a ready status indicator 48. Across the top of front panel 40 are also four additional indicators showing the result of the viscometer reading by indicating which of the four groupings the liquid being tested falls into. First indicator 50 indicates the liquid is thin; second indicator 52 indicates the liquid is nectar like; third indicator 54 indicates the liquid is honey like; and fourth indicator 56 indicates the liquid is spoon thick. Each indicator is a preferably a different color light source, such as a light emitting diode, with color preferably including red for first indicator 50, yellow for second indicator 52, blue for third indicator 54, and green for fourth indicator 56. Preferably, test button 42, position button 44, and indicators 46, 48, 50, 52, 54, and 56 are labeled with an applique or engraved label attached or molded to front panel 40 for easy identification of the meaning of the various indicator lights. 
     Referring to FIGS. 1, 2, 3A, 3B, and 3C, housing 20 is vertically adjustable relative to base assembly 36 through the interaction of spring lever 22 and ratchet teeth 24 of ratchet tooth assembly 26. As most clearly illustrated in FIG. 2, spring lever 22 is positioned within housing 20 so that its central portion 58 is located immediately behind position button 44 of front panel 40. Intermediate portions 60 of spring lever 22 are hingedly retained within boss pairs 62 projecting from the rear of front panel 40. Thus, when position button 44 is depressed, central portion 58 of spring lever 22 is shifted away from front panel 40, and end portions 64 of spring lever 22 pivot in a direction opposite that of central portion 58, thereby becoming disengaged from ratchet teeth 24 of ratchet tooth assemblies 26 of right and left columns 28, 30 of base assembly 36. With end portions 64 of spring lever 22 thus disengaged, housing 20 may be freely vertically adjusted relative to base assembly 36 until a desirable position is reached, at which time position button 44 is released. 
     Reference to FIGS. 2 and 6 shows a stability spacer 66 which projects from the inner surface of front panel inner rail portion 68. Stability spacer 66 bears against but never extends between ratchet teeth 24 of ratchet tooth assemblies 26 to prevent rotational motion of housing 20 relative to base assembly 36. Housing 20 includes front panel inner rail portions 68 on the right and left sides of front panel 40, and each front panel inner rail portion 68 includes a stability spacer 66. 
     Reference to FIGS. 4 and 5 shows the left, right, and intermediate projecting portions 70, 72, 74, respectively, of base member 38. For proper operation of food viscometer 10, it is important to maintain the position of probe 12 at least one inch from all generally vertical sides of beverage container C. Projecting portions 70, 72, 74 are spaced in such a manner to permit easy positioning of food viscometer 10 on the upper edge of beverage container C with probe 12 appropriately positioned an adequate distance from the generally vertical walls thereof. 
     With reference to FIGS. 7A and 7B, disclosed therein are the electronics found on circuit board 16 for controlling motor 32, responding to various inputs and determining various outputs. In particular, circuit board 16 includes a microprocessor 76 that controls the functions of food viscometer 10. Lines 78 and 80 represent output signals from an encoder controlling the speed of motor 32, which signals are input to microprocessor 76 at 82, 84 respectively. Line 86 represents motor current input, originating from line 85, which is amplified by amplification circuit 88, the output from which is detected by microprocessor 76 at line 90. Microprocessor 76 analyzes signals from the encoder to ensure that motor 32 is operating at approximately 240 rpm, although a +/-10% deviation is considered acceptable for proper operation of food viscometer 10. Feedback from microprocessor 76 to adjust the speed of motor 32 is transmitted from line 87 and fed through the motor connector at line 89. Microprocessor 76 also analyzes motor current to determine resistance to spinning probe 12, and thereby calculate the viscosity of the fluid F in container C. Based on the results of this calculation, microprocessor 76 sends a signal to illuminate one of the indicators 50, 52, 54 or 56. Line 92 indicates the output from microprocessor 76 to indicator 50, line 94 indicates the output to indicator 52, line 96 indicates the output to indicator 54, and line 98 indicates the output to indicator 56. 
     Prior to each use of food viscometer 10, the unit must be calibrated to obtain an accurate measurement. The calibration process is simple, requiring only that before positioning probe 12 into fluid F, the user press test button 42, at which time wait status indicator 46 will illuminate. When calibration is complete, ready status indicator 48 will illuminate and a beep will sound. Food viscometer 10 is now calibrated and ready for use. The output from microprocessor 76 to wait status indicator 46 is indicated by line 100, and the output to ready status indicator 48 is indicated by line 102. The output to beeper 104 is indicated by line 106. 
     The steps for use following calibration are equally straightforward. Food viscometer 10 is positioned above beverage container C, with base member 38 resting on the upper edge thereof as illustrated in FIG. 5, and probe 12 extending into fluid F. Holding base assembly 36 in position, the user presses position button 44 and raises or lowers housing 20 relative to base assembly 36 until probe 12 extends into fluid F approximately two inches. It is important that probe 12 not contact the bottom surface of beverage container C, and it is preferable that there be at least a 0.25 inch space therebetween. Further, it is preferred that the diameter of probe 12 be approximately 0.25 inch, and it is important that the inside diameter of beverage container C be at least approximately 2.125 inches. Once probe 12 extends to the proper depth in fluid F, position button 44 may be released, and the user may press test button 42. Microprocessor 76 actuates motor 32, analyzes feedback from the encoder and amplification circuit 88, determines the viscosity of fluid F, illuminates one of the appropriate indicators 50, 52, 54, or 56, and instructs beeper 104 to beep twice. 
     Those skilled in the art will further appreciate that the present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof. In that, the foregoing description of the present invention discloses only exemplary embodiments thereof, it is to be understood that other variations are contemplated as being within the scope of the present invention. Accordingly, the present invention is not limited in the particular embodiments which have been described in detail therein. Rather, reference should be made to the appended claims as indicative of the scope and content of the present invention.