Apparatus and method for determining the depth of liquid in a drum

Abstract

Apparatus and method for determining: proper operation of a cleaning system, the depth of liquid in a drum, the predicted failure of a pump, improving the ability to monitor cleaning system, improving the ability to monitor dairy wash systems, improving the ability to monitor animal husbandry systems, and/or increasing the efficiency with which various types of equipment, fluid levels, and/or systems can be serviced or monitored.

I claim: 
     
         1 : A sensor apparatus for measuring a depth of a liquid in a drum, the sensor apparatus comprising:
 a tube having a first end and a second end, the second end being configured for placement within the liquid;   a seal positioned in the tube and spaced from the second end;   a first sensor disposed in the tube between the seal and the second end and configured to measure air pressure in the tube;   a processor in electronic communication with the first sensor;   a second sensor in electronic communication with the processor, the second sensor being configured to measure atmospheric pressure outside of the drum.   
     
     
         2 : The sensor apparatus of  claim 1 , further comprising an opening located in the second end of the tube configured to let the liquid in the drum partially fill the tube between the second end and the seal, the second end being irregular in shape such that positioning of the second end on a flat bottom of the drum will not prevent flow of liquid into the tube via the drum. 
     
     
         3 : The sensor apparatus of  claim 1 , further comprising a shield located between the second end and the seal, the shield being configured to form a barrier between the first sensor and an inner surface of the tube such that a drop of the liquid is less likely to flow along the inner surface of the tube and contact the first sensor, the shield is configured to leave at least one air passageway between the first sensor and the second end so that the air pressure measurements of the first sensor are not impeded by the shield. 
     
     
         4 : The sensor apparatus of  claim 1 , wherein the location of the second sensor may be any one of on the first end, between the seal and the first end, in a compartment attached to the tube, and spaced from the sensor apparatus. 
     
     
         5 : The sensor apparatus of  claim 1 , wherein the sensor apparatus is configured for insertion via a hole in a top of the drum, and wherein the sensor apparatus comprises an outer tube disposed over the tube, the outer tube having a third end and a fourth end, the outer tube configured to withdraw the liquid from the drum when the sensor apparatus is inserted into the hole in the top of the drum. 
     
     
         6 : The sensor apparatus of  claim 5 , wherein the third end of the outer tube is sealed to the tube at a location on the tube spaced from the second end. 
     
     
         7 : The sensor apparatus of  claim 5 , wherein at least a portion of the tube protrudes from the fourth end of the outer tube so that withdrawal of the liquid from the drum via the outer tube does not create suction that seals the outer tube to a bottom of the drum. 
     
     
         8 : The sensor apparatus of  claim 5 , wherein a hose is located on the outer tube and in fluid communication therewith such that liquid withdrawn from the drum via the outer tube then traverses the hose. 
     
     
         9 : The sensor apparatus of  claim 5 , wherein a first area defined by an axial cross section of the fourth end of the outer tube is greater than a second area defined by an axial cross section of the third end of the outer tube. 
     
     
         10 : The sensor apparatus of  claim 5 , wherein the second sensor is located in a container positioned on the first end of the tube, the container forming a second seal between the outer tube and the tube, and, the third end of the outer tube and the atmosphere. 
     
     
         11 : The sensor apparatus of  claim 9 , further comprising at least one device located within the fourth end and configured to prevent the liquid in the outer tube from exiting the sensor apparatus between the tube and the outer tube via the fourth end when the sensor apparatus is withdrawn from the liquid in the drum, the at least one device not preventing the liquid from entering the outer tube through the fourth end. 
     
     
         12 : The sensor apparatus of  claim 1 , wherein the processor is configured to compute a volume of the liquid in the drum based on the measurements of the first sensor and the second sensor, and, also using a plurality of inputs representing at least one of a dimension of the drum, a dimension of the sensor apparatus, and a specific gravity of the liquid. 
     
     
         13 : The sensor apparatus of  claim 12 , wherein the processor is configured for entry of the plurality of inputs via a remote electronic device. 
     
     
         14 : The sensor apparatus of  claim 13 , further comprising an opening located in one of between the seal and the second end of the tube and in the second end of the tube, the opening configured to let the liquid in the drum partially fill the tube, wherein the processor is configured to automatically determine the depth of the liquid in the drum, according to:
     H =( P   b   −P   a )/(PPIC*SG liquid ) wherein   P b  is the pressure in the drum at the opening of the tube as measured by the first sensor,   P a  is the atmospheric pressure outside the drum as measured by the second sensor,   SG liquid  is the specific gravity of the liquid inside the drum,   H is the depth, or height, of the liquid inside the drum above the opening,   PPIC is determined by ((H−TUBE liquidinches )* 249 . 17 )/H)   TUBE liquidinches  is the height of liquid in the tube above the opening,   249.17 is the standard pressure exerted by a one inch column of water.   
     
     
         15 : The sensor apparatus of  claim 14 , wherein the processor is further configured to automatically determine the volume of the liquid in the drum and take into account any adjustment needed due to the presence of the sensor apparatus therein by using the depth of the liquid in the drum and dimensions of the drum to determine an initial volume of liquid in the drum, then the processor automatically adjusts the initial volume of liquid in the drum to get a final volume of liquid in the drum that takes into account the sensor apparatus, according to:
     V drum-final= V drum-initial−(( H - D liquid-in-sensor)* A ), wherein
   H is the depth of liquid in the drum above the opening;   Vdrum-final is the final volume of liquid in the drum above the opening;   Vdrum-initial is the initial volume of liquid in the drum above the opening;   A is a cross sectional area of the tube;   Dliquid-in-sensor is the depth of the liquid in the tube determined as follows:
     D liquid-in-sensor=( L −((( Pi*Vi/Ti )*( Tf/Pf ))/ A )), wherein
 
   L is a length of the tube;   Pi is the initial pressure in the tube prior to insertion of the tube in the liquid;   Vi is the initial volume of the tube that is calculated by the dimensions of the tube;   Ti is the initial temperature of air in the tube;   Pf is a pressure in the tube when the tube is submerged in the liquid as calculated by the first sensor; and   Tf is the final temperature of the air inside the tube when the tube is submerged.   
     
     
         16 : The sensor apparatus of  claim 15 , wherein the processor is configured to collect a plurality of usage data comprising at least one of a time and a temperature of liquid withdrawn from the drum. 
     
     
         17 : The sensor apparatus of  claim 16 , wherein the processor is configured to compare the plurality of usage data against a plurality of predetermined data and issue an alert when a discrepancy occurs. 
     
     
         18 : The sensor apparatus of  claim 11 , wherein the second end of the tube is located off-center in the fourth end of the outer tube to provide additional room for the operation of the at least one device. 
     
     
         19 : A sensor apparatus for measuring a depth of a liquid in a drum, the sensor apparatus comprising:
 a tube having a first end and a second end, the second end being configured for placement within the liquid;   a seal positioned in the tube and spaced from the second end;   a first sensor disposed in the tube between the seal and the second end and configured to measure air pressure in the tube;   a processor in electronic communication with the first sensor;   an outer tube disposed over the tube, the outer tube having a third end and a fourth end, the outer tube configured to withdraw the liquid from the drum when the sensor apparatus is inserted into a hole in a top of the drum.   
     
     
         20 : A sensor apparatus for measuring a depth of a liquid in a drum above an initial drum liquid height, the drum including a sidewall, the sensor apparatus comprising:
 a tube having a first end and a second end, the second end being disposed on the sidewall of the drum such that the tube and an inside of the drum are in fluid communication, the second end being located on the sidewall proximate the initial drum liquid height;   a seal positioned in the tube and spaced from the second end;   a first sensor disposed in the tube between the seal and the second end and configured to measure air pressure in the tube;   a processor in electronic communication with the first sensor, wherein the processor automatically determines the depth of liquid in the tank not including the initial drum liquid height.   
     
     
         21 : The sensor apparatus of  claim 20 : further comprising an outlet for withdrawing liquid from the drum, the outlet being configured to withdraw liquid from a bottom of the drum. 
     
     
         22 : The sensor apparatus of  claim 21 , wherein the processor is configured to compute a preferred volume of the liquid in the drum based on the measurements of the first sensor and a second sensor configured to measure pressure outside the drum, and, also using a plurality of inputs representing at least one of a dimension of the drum, a dimension of the sensor apparatus, and a specific gravity of the liquid. 
     
     
         23 : The sensor apparatus of  claim 22 , wherein the processor is configured for entry of the plurality of inputs via a remote electronic device. 
     
     
         24 : The sensor apparatus of  claim 22 , further comprising the second end of the tube being configured to let the liquid in the drum partially fill the tube, wherein the processor is configured to automatically determine the depth of the liquid in the drum, according to:
     H =( P   b   −P   a )/(PPIC*SG liquid ), wherein   P b  is the pressure in the drum at the opening in the tube as measured by the first sensor,   P a  is the atmospheric pressure outside the drum as measured by the second sensor,   SG liquid  is the specific gravity of the liquid inside the drum,   H is the depth, or height, of the liquid inside the drum above the effective location on the tube,   PPIC is determined by ((H−TUBE liquidinches )*249.17)/H)   TUBE liquidinches  is the height of liquid in the tube above the effective location,   249.17 is the standard pressure exerted by a one inch column of water.   
     
     
         25 : The sensor apparatus of  claim 24 , wherein the processor is further configured to automatically determine the preferred volume of the liquid in the drum and take into account any adjustment needed due to the presence of the sensor apparatus therein by using the depth of the liquid in the drum above the initial drum liquid height and dimensions of the drum to determine an initial volume of liquid in the drum, then the processor automatically adjusts the initial volume of liquid in the drum to get a final volume of liquid in the drum that takes into account the sensor apparatus, according to:
     V drum-final= V drum-initial−(( H - D liquid-in-sensor)* A ), wherein
   H is the depth of liquid in the drum above the opening;   Vdrum-final is the final volume of liquid in the drum above the opening;   Vdrum-initial is the initial volume of liquid in the drum above the opening;   A is a cross sectional area of the tube;   Dliquid-in-sensor is the depth of the liquid in the tube over the opening determined as follows:
     D liquid-in-sensor=( L −((( Pi*Vi/Ti )*( Tf/Pf ))/ A )), wherein
 
   L is a length of the tube as measured from a point on the tube corresponding to the effective location;   Pi is the initial pressure in the tube prior to liquid entering the tube;   Vi is the initial volume of the tube that is calculated by the dimensions of the tube;   Ti is the initial temperature of air in the tube;   Pf is a pressure in the tube when the tube is submerged in the liquid as calculated by the first sensor; and   Tf is the final temperature of the air inside the tube when the tube is submerged.