Patent Publication Number: US-RE48204-E

Title: Method and apparatus for limiting acidic corrosion in fuel delivery systems

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a reissue of U.S. Pat. No. 9,428,375, issued Aug. 30, 2016, which claims priority from U.S. Provisional Patent Application Ser. No. 61/691,994, filed Aug. 22, 2012, the disclosures of which are hereby expressly incorporated by reference herein in their entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to monitoring fuel delivery systems and, in particular, to a method and apparatus for monitoring fuel delivery systems to limit acidic corrosion. 
     BACKGROUND OF THE DISCLOSURE 
     A fuel delivery system typically includes one or more underground storage tanks that store various fuel products and one or more fuel dispensers that dispense the fuel products to consumers. The underground storage tanks may be coupled to the fuel dispensers via corresponding underground fuel delivery lines. 
     In the context of an automobile fuel delivery system, for example, the fuel products may be delivered to consumers&#39; automobiles. In such systems, the fuel products may contain a blend of gasoline and alcohol, specifically ethanol. Blends having about 2.5 vol. % ethanol (“E-2.5”), 5 vol. % ethanol (“E-5”), 10 vol. % ethanol (“E-10”), or more, in some cases up to 85 vol. % ethanol (“E-85”), are now available as fuel for cars and trucks in the United States and abroad. 
     Sumps (i.e., pits) may be provided around the equipment of the fuel delivery system. Such sumps may trap liquids and vapors to prevent environmental releases. Also, such sumps may facilitate access and repairs to the equipment. Sumps may be provided in various locations throughout the fuel delivery system. For example, dispenser sumps may be located beneath the fuel dispensers to provide access to piping, connectors, valves, and other equipment located beneath the fuel dispensers. As another example, turbine sumps may be located above the underground storage tanks to provide access to turbine pump heads, piping, leak detectors, electrical wiring, and other equipment located above the underground storage tanks. 
     Underground storage tanks and sumps may experience premature corrosion. Efforts have been made to control such corrosion with fuel additives, such as biocides and corrosion inhibitors. However, the fuel additives may be ineffective against certain microbial species, become depleted over time, and cause fouling, for example. Efforts have also been made to control such corrosion with rigorous and time-consuming water maintenance practices, which are typically disfavored by retail fueling station operators. 
     SUMMARY 
     The present disclosure relates to a method and apparatus for monitoring a fuel delivery system to limit acidic corrosion. An exemplary monitoring system includes a controller, at least one monitor, and an output. The monitoring system may collect and analyze data indicative of a corrosive environment in the fuel delivery system. The monitoring system may also automatically warn an operator of the fueling station of the corrosive environment so that the operator can take preventative or corrective action. 
     According to an embodiment of the present disclosure, a fuel delivery system is provided including a storage tank containing a fuel product, a fuel delivery line in communication with the storage tank, at least one monitor that collects data indicative of a corrosive environment in the fuel delivery system, and a controller in communication with the at least one monitor to receive collected data from the at least one monitor, the controller being programmed to issue a warning based on the collected data from the at least one monitor. 
     According to another embodiment of the present disclosure, a method is provided for monitoring a fuel delivery system and includes the steps of directing a fuel product from a storage tank to a fuel dispenser via a fuel delivery line, collecting data indicative of a corrosive environment in the fuel delivery system, and issuing a warning based on the collected data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  depicts an exemplary fuel delivery system of the present disclosure showing above ground components, such as a fuel dispenser, and below ground components, such as a storage tank containing a fuel product, a fuel delivery line, a turbine sump, and a dispenser sump; 
         FIG. 2  is a cross-sectional view of the storage tank and the turbine sump of  FIG. 1 ; 
         FIG. 3  is a schematic view of an exemplary monitoring system of the present disclosure, the monitoring system including a controller, at least one monitor, and an output; 
         FIG. 4  is a schematic view of a first exemplary monitor for use in the monitoring system of  FIG. 3 ; 
         FIG. 5  is a schematic view of a second exemplary monitor for use in the monitoring system of  FIG. 3 ; and 
         FIG. 6  is a schematic view of a third exemplary monitor for use in the monitoring system of  FIG. 3 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     An exemplary fuel delivery system  10  is shown in  FIG. 1 . Fuel delivery system  10  includes a fuel dispenser  12  for dispensing a liquid fuel product  14  from a liquid storage tank  16  to consumers. Each storage tank  16  is fluidly coupled to one or more dispensers  12  via a corresponding fuel delivery line  18 . Storage tank  16  and delivery line  18  are illustratively positioned underground, but it is also within the scope of the present disclosure that storage tank  16  and/or delivery line  18  may be positioned above ground. 
     Fuel delivery system  10  of  FIG. 1  also includes a pump  20  to draw fuel product  14  from storage tank  16  and to convey fuel product  14  through delivery line  18  to dispenser  12 . Pump  20  is illustratively a submersible turbine pump (“STP”) having a turbine pump head  22  located above storage tank  16  and a submersible motor  24  located inside storage tank  16 . However, it is within the scope of the present disclosure that other types of pumps may be used to transport fuel product  14  through fuel delivery system  10 . 
     Fuel delivery system  10  of  FIG. 1  further includes various underground sumps (i.e., pits). A first, dispenser sump  30  is provided beneath dispenser  12  to protect and provide access to piping (e.g., delivery line  18 ), connectors, valves, and other equipment located therein, and to contain any materials that may be released beneath dispenser  12 . A second, turbine sump  32 , which is also shown in  FIG. 2 , is provided above storage tank  16  to protect and provide access to pump  20 , piping (e.g., delivery line  18 ), leak detector  34 , electrical wiring  36 , and other equipment located therein. Turbine sump  32  is illustratively capped with an underground lid  38  and a ground-level manhole cover  39 , which protect the equipment inside turbine sump  32  when installed and allow access to the equipment inside turbine sump  32  when removed. 
     According to an exemplary embodiment of the present disclosure, fuel delivery system  10  is an automobile fuel delivery system. In this embodiment, fuel product  14  may be a gasoline/ethanol blend that is delivered to consumers&#39; automobiles, for example. The concentration of ethanol in the gasoline/ethanol blended fuel product  14  may vary from 0 vol. % to 15 vol. % or more. For example, fuel product  14  may contain about 2.5 vol. % ethanol (“E-2.5”), about 5 vol. % ethanol (“E-5”), about 7.5 vol. % ethanol (“E-7.5”), about 10 vol. % ethanol (“E-10”), about 15 vol. % ethanol (“E-15”), or more, in some cases up to about 85 vol. % ethanol (“E-85”). 
     In addition to being present in storage tank  16  as part of the gasoline/ethanol blended fuel product  14 , ethanol may find its way into other locations of fuel delivery system  10  in a vapor or liquid state, including dispenser sump  30  and turbine sump  32 . In the event of a fluid leak from dispenser  12 , for example, some of the gasoline/ethanol blended fuel product  14  may drip from dispenser  12  into dispenser sump  30  in a liquid state. Also, in the event of a vapor leak from storage tank  16 , ethanol vapor in the ullage of storage tank  16  may escape from storage tank  16  and travel into turbine sump  32 . In certain situations, turbine sump  32  and/or components contained therein (e.g., metal fittings, metal valves, metal plates) may be sufficiently cool in temperature to condense the ethanol vapor back into a liquid state in turbine sump  32 . Along with ethanol, water from the surrounding soil or another source may also find its way into sumps  30 ,  32  in a vapor or liquid state, such as by dripping into sumps  30 ,  32  in a liquid state or by evaporating and then condensing in sumps  30 ,  32 . Ethanol and/or water vapor leaks into sumps  30 ,  32  may occur through various connection points in sumps  30 ,  32 , for example. Ethanol and/or water may escape from ventilated sumps  30 ,  32  but may become trapped in unventilated sumps  30 ,  32 . 
     In the presence of certain bacteria, ethanol that is present in fuel delivery system  10  may be oxidized to produce acetate, according to Reaction I below. The acetate may then be protonated to produce acetic acid, according to Reaction II below.
 
CH 3 CH 2 OH+H 2 O→CH 3 COO − +H + +2H 2   (I)
 
CH 3 COO − +H + →CH 3 COOH  (II)
 
     The conversion of ethanol to acetic acid may also occur in the presence of oxygen according to Reaction III below.
 
2CH 3 CH 2 OH+O 2 →2CH 3 COOH+2H 2 O  (III)
 
     Acetic acid producing bacteria may produce acetate and acetic acid by a metabolic fermentation process, which is used commercially to produce vinegar, for example. Acetic acid producing bacteria generally belong to the Acetobacteraceae family, which includes the genera Acetobacter and Gluconobacter. Acetic acid producing bacteria are very prevalent in nature and may be present in the soil around fuel delivery system  10 , for example. Such bacteria may find their way into sumps  30 ,  32  to drive Reactions I-III above, such as when soil or debris falls into sumps  30 ,  32  or when rainwater seeps into sumps  30 ,  32 . 
     The products of Reactions I-III above may reach equilibrium in sumps  30 ,  32 , with some of the acetate and acetic acid dissolving into liquid water that is present in sumps  30 ,  32 , and some of the acetate and acetic acid volatilizing into a vapor state. In general, the amount acetate or acetic acid that is present in the vapor state is proportional to the amount of acetate or acetic acid that is present in the liquid state (i.e, the more acetate or acetic acid that is present in the vapor state, the more acetate or acetic acid that is present in the liquid state). 
     Even though acetic acid is classified as a weak acid, it may be corrosive to fuel delivery system  10 , especially at high concentrations. For example, the acetic acid may react to deposit metal oxides (e.g., rust) or metal acetates on metallic fittings of fuel delivery system  10 . Because Reactions I-III are microbiologically-influenced reactions, these deposits in fuel delivery system  10  may be tubular or globular in shape. 
     To limit corrosion in fuel delivery system  10 , a monitoring system  100  and a corresponding monitoring method are provided herein. As shown in  FIG. 3 , the illustrative monitoring system  100  includes controller  102 , one or more monitors  104  in communication with controller  102 , and output  106  in communication with controller  102 , each of which is described further below. 
     Controller  102  of monitoring system  100  illustratively includes a microprocessor  110  (e.g., a central processing unit (CPU)) and an associated memory  112 . Controller  102  may be any type of computing device capable of accessing a computer-readable medium having one or more sets of instructions (e.g., software code) stored therein and executing the instructions to perform one or more of the sequences, methodologies, procedures, or functions described herein. In general, controller  102  may access and execute the instructions to collect, sort, and/or analyze data from monitor  104 , determine an appropriate response, and communicate the response to output  106 . Controller  102  is not limited to being a single computing device, but rather may be a collection of computing devices (e.g., a collection of computing devices accessible over a network) which together execute the instructions. The instructions and a suitable operating system for executing the instructions may reside within memory  112  of controller  102 , for example. Memory  112  may also be configured to store real-time and historical data and measurements from monitors  104 , as well as reference data. Memory  112  may store information in database arrangements, such as arrays and look-up tables. 
     Controller  102  of monitoring system  100  may be part of a larger controller that controls the rest of fuel delivery system  10 . In this embodiment, controller  102  may be capable of operating and communicating with other components of fuel delivery system  10 , such as dispenser  12  ( FIG. 1 ), pump  20  ( FIG. 2 ), and leak detector  34  ( FIG. 2 ), for example. An exemplary controller  102  is the TS-550 Fuel Management System available from Franklin Fueling Systems Inc. of Madison, Wis. 
     Monitor  104  of monitoring system  100  is configured to automatically and routinely collect data indicative of a corrosive environment in fuel delivery system  10 . In operation, monitor  104  may draw in a liquid or vapor sample from fuel delivery system  10  and directly test the sample or test a target material that has been exposed to the sample, for example. In certain embodiments, monitor  104  operates continuously, collecting samples and measuring data approximately once every second or minute, for example. Monitor  104  is also configured to communicate the collected data to controller  102 . In certain embodiments, monitor  104  manipulates the data before sending the data to controller  102 . In other embodiments, monitor  104  sends the data to controller  102  in raw form for manipulation by controller  102 . The illustrative monitor  104  is wired to controller  102 , but it is also within the scope of the present disclosure that monitor  104  may communicate wirelessly (e.g., via an internet network) with controller  102 . 
     Depending on the type of data being collected by each monitor  104 , the location of each monitor  104  in fuel delivery system  10  may vary. Returning to the illustrated embodiment of  FIG. 2 , for example, monitor  104 ′ is positioned in the liquid space (e.g, middle or bottom) of storage tank  16  to collect data regarding the liquid fuel product  14  in storage tank  16 , monitor  104 ″ is positioned in the ullage or vapor space (e.g., top) of storage tank  16  to collect data regarding any vapors present in storage tank  16 , monitor  104 ′″ is positioned in the liquid space (e.g., bottom) of turbine sump  32  to collect data regarding any liquids present in turbine sump  32 , and monitor  104 ″″ is positioned in the vapor space (e.g., top) of turbine sump  32  to collect data regarding any vapors present in turbine sump  32 . Monitor  104  may be positioned in other suitable locations of fuel delivery system  10 , including delivery line  18  and dispenser sump  30  ( FIG. 1 ), for example. Various monitors  104  for use in monitoring system  100  of  FIG. 3  are discussed further below. 
     Output  106  of monitoring system  100  is capable of communicating an alarm or warning from controller  102  to an operator. Output  106  may be in the form of a visual indication device (e.g., a gauge, a display screen, lights, a printer), an audio indication device (e.g., a speaker, an audible alarm), a tactile indication device, or another suitable device for communicating information to the operator, as well as combinations thereof. The illustrative output  106  is wired to controller  102 , but it is also within the scope of the present disclosure that output  106  may communicate wirelessly (e.g., via an internet network) with controller  102 . To facilitate communication between output  106  and the operator, output  106  may be located in the operator&#39;s control room or office, for example. 
     In operation, and as discussed above, controller  102  collects, sorts, and/or analyzes data from monitor  104 , determines an appropriate response, and communicates the response to output  106 . According to an exemplary embodiment of the present disclosure, output  106  warns the operator of a corrosive environment in fuel delivery system  10  before the occurrence of any corrosion or any significant corrosion in fuel delivery system  10 . In this embodiment, corrosion may be prevented or minimized. It is also within the scope of the present disclosure that output  106  may alert the operator to the occurrence of corrosion in fuel delivery system  10  to at least avoid further corrosion. 
     Various factors may influence whether controller  102  issues an alarm or warning from output  106  that a corrosive environment is present in fuel delivery system  10 . One factor includes the concentration of acidic molecules in fuel delivery system  10 , with controller  102  issuing an alarm or warning from output  106  when the measured concentration of acidic molecules in fuel delivery system  10  exceeds an acceptable concentration of acidic molecules in fuel delivery system  10 . The concentration may be expressed in various units. For example, controller  102  may activate output  106  when the measured concentration of acidic molecules in fuel delivery system  10  exceeds 25 ppm, 50 ppm, 100 ppm, 150 ppm, 200 ppm, or more, or when the measured concentration of acidic molecules in fuel delivery system  10  exceeds 25 mg/L, 50 mg/L, 100 mg/L, 150 mg/L, 200 mg/L, or more. At or beneath the acceptable concentration, corrosion in fuel to delivery system  10  may be limited. Another factor includes the concentration of hydrogen ions in fuel delivery system  10 , with controller  102  issuing an alarm or warning from output  106  when the measured concentration of hydrogen ions in fuel delivery system  10  exceeds an acceptable concentration of hydrogen ions in fuel delivery system  10 . For example, controller  102  may activate output  106  when the hydrogen ion concentration causes the pH in fuel delivery system  10  to drop below 5, 4, 3, or 2, for example. Within the acceptable pH range, corrosion in fuel delivery system  10  may be limited. Yet another factor includes the concentration of bacteria in fuel delivery system  10 , with controller  102  issuing an alarm or warning from output  106  when the measured concentration of bacteria in fuel delivery system  10  exceeds an acceptable concentration of bacteria in fuel delivery system  10 . At or beneath the acceptable concentration, the production of corrosive materials in fuel delivery system  10  may be limited. 
     Controller  102  may be programmed to progressively vary the alarm or warning communication from output  106  as the risk of corrosion in fuel delivery system  10  increases. For example, controller  102  may automatically trigger a minor alarm (e.g., a blinking light) when monitor  104  detects a relatively low acid concentration level (e.g., 5 ppm) in fuel delivery system  10 , a moderate alarm (e.g., an audible alarm) when monitor  104  detects a moderate acid concentration level (e.g., 10 ppm) in fuel delivery system  10 , and a severe alarm (e.g., a telephone call or an e-mail to the gas station operator) when monitor  104  detects a relatively high acid concentration level (e.g., 25 ppm) in fuel delivery system  10 . 
     The alarm or warning communication from output  106  allows the operator to take precautionary or corrective measures to limit corrosion of fuel delivery system  10 . For example, if an alarm or warning communication is signaled from turbine sump  32  ( FIG. 2 ), the operator may remove manhole cover  39  and lid  38  to clean turbine sump  32 , which may involve removing bacteria and potentially corrosive liquids and vapors from turbine sump  32 . As another example, the operator may inspect fuel delivery system  10  for a liquid leak or a vapor leak that allowed ethanol and/or its acidic reaction products to enter turbine sump  32  in the first place. 
     As discussed above, monitoring system  100  includes one or more monitors  104  that collect data indicative of a corrosive environment in fuel delivery system  10 . Each monitor  104  may vary in the type of data that is collected, the type of sample that is evaluated for testing, and the location of the sample that is evaluated for testing, as exemplified below. 
     In one embodiment, monitor  104  collects electrical data indicative of a corrosive environment in fuel delivery system  10 . An exemplary electrical monitor  104 a is shown in  FIG. 4  and includes an energy source  120 , a corrosive target material  122  that is exposed to a liquid or vapor sample S from fuel delivery system  10 , and a sensor  124 . Target material  122  may be designed to corrode before the equipment of fuel delivery system  10  corrodes. Target material  122  may be constructed of or coated with a material that is susceptible to acidic corrosion, such as copper or low carbon steel. Also, target material  122  may be relatively thin or small in size compared to the equipment of fuel delivery system  10  such that even a small amount of corrosion will impact the structural integrity of target material  122 . For example, target material  122  may be in the form of a thin film or wire. 
     In use, energy source  120  directs an electrical current through target material  122 . When target material  122  is intact, sensor  124  senses the electrical current traveling through target material  122 . However, when exposure to sample S causes target material  122  to corrode and potentially break, sensor  124  will sense a decreased electrical current, or no current, traveling through target material  122 . It is also within the scope of the present disclosure that the corrosion and/or breakage of target material  122  may be detected visually, such as by using a camera as sensor  124 . First monitor  104 a may share the data collected by sensor  124  with controller  102  ( FIG. 3 ) to signal a corrosive environment in fuel delivery system  10 . 
     Another exemplary electrical monitor  104 b is shown in  FIG. 5  and includes opposing, charged metal plates  130 . The electrical monitor  104 b operates by measuring electrical properties (e.g., capacitance, impedance) of a liquid or vapor sample S that has been withdrawn from fuel delivery system  10 . In the case of a capacitance monitor  104 b, for example, the sample S is directed between plates  130 . Knowing the size of plates  130  and the distance between plates  130 , the dielectric constant of the sample S may be calculated. As the quantity of acetate or acetic acid in the sample S varies, the dielectric constant of the sample S may also vary. The electrical monitor  104 b may share the collected data with controller  102  ( FIG. 3 ) to signal a corrosive environment in fuel delivery system  10 . 
     In another embodiment, monitor  104  collects electrochemical data indicative of a corrosive environment in fuel delivery system  10 . An exemplary electrochemical monitor (not shown) performs potentiometric titration of a sample that has been withdrawn from fuel delivery system  10 . A suitable potentiometric titration device includes an electrochemical cell with an indicator electrode and a reference electrode that maintains a consistent electrical potential. As a titrant is added to the sample and the electrodes interact with the sample, the electric potential across the sample is measured. Potentiometric or chronopotentiometric sensors, which may be based on solid-state reversible oxide films, such as that of iridium, may be used to measure potential in the cell. As the concentration of acetate or acetic acid in the sample varies, the potential may also vary. The potentiometric titration device may share the collected data with controller  102  ( FIG. 3 ) to signal a corrosive environment in fuel delivery system  10 . An electrochemical monitor may also operate by exposing the sample to an electrode, performing a reduction-oxidation with the sample at the electrode, and measuring the resulting current, for example. 
     In yet another embodiment, monitor  104  collects optical data indicative of a corrosive environment in fuel delivery system  10 . An exemplary optical monitor  104 c is shown in  FIG. 6  and includes a light source  140 , an optical target material  142  that is exposed to a liquid or vapor sample S from fuel delivery system  10 , and an optical detector  144 . Target material  142  may be constructed of or coated with a material (e.g., an acid-sensitive polymer) that changes optical properties (e.g., color) in the presence of H +  protons from the sample S. Suitable target materials  142  include pH indicators that change color when target material  142  is exposed to an acidic pH, such as a pH less than about 5, 4, 3, or 2, for example. The optical properties of target material  142  may be configured to change before the equipment of fuel delivery system  10  corrodes. Detector  144  may use optical fibers as the sensing element (i.e., intrinsic sensors) or as a means of relaying signals to a remote sensing element (i.e., extrinsic sensors). 
     In use, light source  140  directs a beam of light toward target material  142 . Before target material  142  changes color, for example, detector  144  may detect a certain reflection, transmission (i.e., spectrophotometry), absorbtion (i.e., densitometry), and/or refraction of the the light beam from target material  142 . However, after target material  142  changes color, detector  144  will detect a different reflection, transmission, absorbtion, and/or refraction of the the light beam. It is also within the scope of the present disclosure that the changes in target material  142  may be detected visually, such as by using a camera as detector  144 . Third monitor  104 c may share the data collected by detector  144  with controller  102  ( FIG. 3 ) to signal a corrosive environment in fuel delivery system  10 . 
     In still yet another embodiment, monitor  104  collects spectroscopic data indicative of a corrosive environment in fuel delivery system  10 . An exemplary spectrometer (not shown) operates by subjecting a liquid or vapor sample from fuel delivery system  10  to an energy source and measuring the radiative energy as a function of its wavelength and/or frequency. Suitable spectrometers include, for example, infrared (IR) electromagnetic spectrometers, ultraviolet (UV) electromagnetic spectrometers, gas Chromatography-mass spectrometers (GC-MS), and nuclear magnetic resonance (NMR) spectrometers. Suitable spectrometers may detect absorption from a ground state to an excited state, and/or fluorescence from the excited state to the ground state. The spectroscopic data may be represented by a spectrum showing the radiative energy as a function of wavelength and/or frequency. It is within the scope of the present disclosure that the spectrum may be edited to hone in on certain impurities in the sample, such as acetate and acetic acid, which may cause corrosion in fuel delivery system  10 , as well as sulfuric acid, which may cause odors in fuel delivery system  10 . As the impurities develop in fuel delivery system  10 , peaks corresponding to the impurities would form and/or grow on the spectrum. The spectrometer may share the collected data with controller  102  ( FIG. 3 ) to signal a corrosive environment in fuel delivery system  10 . 
     In still yet another embodiment, monitor  104  collects microbial data indicative of a corrosive environment in fuel delivery system  10 . An exemplary microbial detector (not shown) operates by exposing a liquid or vapor sample from fuel delivery system  10  to a fluorogenic enzyme substrate, incubating the sample and allowing any bacteria in the sample to cleave the enzyme substrate, and measuring fluorescence produced by the cleaved enzyme substrate. The concentration of the fluorescent product may be directly related to the concentration of acetic acid producing bacteria (e.g., Acetobacter, Gluconobacter) in the sample. Suitable microbial detectors are commercially available from Mycometer, Inc. of Tampa, Fla. The microbial detector may share the collected data with controller  102  ( FIG. 3 ) to signal a corrosive environment in fuel delivery system  10 . 
     While this invention has been described as having exemplary designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.