Abstract:
An apparatus and method for separating dissolved gasses from a fluid to produce de-aerated fluid which includes a fluid pump, a gas separator, and a vacuum pump for removing liberated dissolved gasses from the gas separator. In one particular embodiment, a unified pump/meter unit is used to both pump fluid, as well as volumetrically measure the amount of de-aerated fluid pumped.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an air separator system for de-aerating fluid, and in particular, a system for use in conjunction with a fuel dispenser for de-aerating liquid fuel. 
     2. Description of the Related Art 
     Fuel dispensers contain a fuel storage tank, a fuel pump, and a fuel meter. The fuel pump, conducts fuel from the fuel storage tank and the meter measures the volume of fuel to be dispensed. Liquid fuel may contain dissolved gasses, for example, components of ambient air such as oxygen, nitrogen, etc., as well as hydrocarbons. These dissolved gasses contribute to the volume of fuel pumped from the fuel storage tank. In order to get an accurate measurement of the volume of liquid fuel to be dispensed, dissolved gasses must be removed from the fuel before metering. In addition, many fuel dispensers manufactured today contain a vapor recovery system. The vapor recovery system includes a vapor recovery pump for evacuating fuel vapors from the fuel tank of a vehicle being refueled. 
     Traditionally, fuel dispensers contain a gas or an air separator disposed downstream from the fuel pump. The fluid on the inlet side of the pump is in a vacuum and, consequently, the pressure is less than atmospheric air. The low pressure hampers effective air separation and removal. Conversely, the pressure on the downstream or outlet side of a fuel pump is greater than atmospheric air. Therefore, traditional fuel dispensers locate the air separator on the outlet side of a pump where the pressure is higher. 
     One problem with traditional fuel dispenser air separation systems is that the air separation system is located on the outlet side of a fuel pump. The pressure on the downstream or outlet side of a fuel pump is greater than atmospheric air. Pressure higher than atmospheric air assists in the removal of gasses liberated from liquid fuel. However, a less than atmospheric pressure on the inlet side of a pump hampers removal of liberated gasses in an air separator system. Consequently, many current air separation systems will not operate if located on the inlet side of a pump. Therefore, traditional fuel dispensers locate an air separation system on the outlet side of a fuel pump where the pressure is greater than atmospheric air. 
     A second disadvantage of current fuel dispensers air separator systems are that they do not contain a unified pump/meter unit. A unified pump/meter unit volumetrically measures the volume of fuel pumped for accurate measurement of the volume of fuel dispensed from a fuel dispenser. To accurately measure the volume of fuel to be dispensed, air and other dissolved gasses must first be removed from the liquid fuel before measuring the fuel volume. Since traditional fuel dispensers remove air and gasses on the outlet side of a pump, the meter must be located on the outlet side of a air separation system in order to get more accurate measurement. Consequently, traditional fuel dispensers do not contain a unified pump/meter to both pump fuel and provide an accurate measurement of fuel dispensers. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a gas separator, along with vacuum means, are used for removing air and other dissolved gasses from a fluid prior to contact with a fluid pump. The invention, in one form thereof, is an apparatus for separating dissolved gases from a fluid to produce de-aerated fluid. The apparatus includes a fluid pump with a fluid pump inlet and a fluid pump outlet. The apparatus also contains a gas separator which has an upper portion with a gas outlet, a separator fluid inlet, and a separator fluid outlet. Vacuum means removes gas from the gas separator. The vacuum means is in communication with the gas outlet. In one embodiment, the separator fluid outlet is in fluid communication with the fluid pump inlet. In a further embodiment, the apparatus includes a separator gas sensing means operatively associated with the separator upper portion for detecting gas, a gas valve disposed between the gas outlet and the vacuum means, and a gas sensing controller operatively associated with the gas valve. In another, further embodiment, the gas separator is a centrifugal separator. 
     In another embodiment, the present invention is a method of producing de-aerated fluid. The method includes the steps of passing a fluid through a centrifugal separator and applying a vacuum to remove the gas from a portion of the separator. In one particular embodiment, a vapor recovery pump provides the vacuum means to remove the gas from the upper portion of a separator. 
     The invention, in yet another form thereof, is an apparatus for separating dissolved gases from liquid fuel to produce de-aerated fuel. The apparatus includes a pump/meter with a fluid pump inlet and a fluid pump outlet. The apparatus also includes a centrifugal separator having an upper portion with a gas outlet, a separator fluid inlet, and a separator fluid outlet. The separator fluid outlet is in fluid communication with the pump/meter inlet. Vacuum means removes gas from the centrifugal separator and is in communication with the gas outlet. A separator gas sensing means is operatively associated with the separator upper portion for detecting gas. A gas valve is disposed between the gas outlet and the vacuum means. A de-aerated fuel gas sensing means is operatively associated with the de-aerated fluid for detecting gas. A by-pass valve is in fluid communication with the fluid pump outlet. A gas sensing controller is operatively associated with said gas valve and said by-pass valve. In a further embodiment, a vapor recovery system with a vapor recovery pump provides the vacuum means. 
     The invention, in yet another form thereof, is an apparatus for separating dissolved gases from liquid fuel to produce de-aerated fuel. The apparatus includes a pump/meter with a fluid pump inlet and a fluid pump outlet. The apparatus also includes a centrifugal separator having an upper portion with a gas outlet, a separator fluid inlet, and a separator fluid outlet. The separator fluid outlet is in fluid communication with the pump/meter inlet. A Vacuum pump removes gas from the centrifugal separator and is in communication with the gas outlet. A separator gas sensor is operatively associated with the separator upper portion for detecting gas. A gas valve is disposed between the gas outlet and the vacuum pump. A de-aerated fuel gas sensor is operatively associated with the de-aerated fluid for detecting gas. A by-pass valve is in fluid communication with the fluid pump outlet. A gas sensing controller is operatively associated with said gas valve and said by-pass valve. In a further embodiment, a vapor recovery system uses the vacuum pump as a vapor recovery pump. 
     The invention, in yet another form thereof, is a fuel dispenser in which dissolved gases are separated from liquid fuel to produce de-aerated fluid. The fuel dispenser includes a dispenser tank, a hose with a nozzle and a fluid pump. The fluid pump has a fluid pump inlet and a fluid pump outlet. The fuel dispenser also contains a centrifugal separator. The centrifugal separator has a gas outlet, a separator fluid inlet, and a separator fluid outlet. Vacuum means removes gas from the centrifugal separator. The vacuum means is in communication with the gas outlet. In one embodiment, the separator fluid outlet is in fluid communication with the fluid pump inlet. In a further embodiment, the fuel dispenser includes a separator gas sensing means operatively associated with the centrifugal separator for detecting gas, a gas valve disposed between the gas outlet and the vacuum means, and a gas sensing controller operatively associated with the gas valve. 
     An advantage of the present invention is that the air separator system is located on the inlet or upstream side of a pump rather than the outlet or downstream side of the pump. The centrifugal separator with vacuum means allows for effective separation of dissolved gases from a liquid even when the air separator system is located on the inlet side of a pump. 
     Another advantage of the present invention is the ability for a fuel dispenser to utilize a unified pump/meter unit. The fluid is de-aerated by an air separation system located on the inlet side of a pump. Therefore, since de-aerated fluid is being pumped through the pump/meter unit, a more accurate volumetric measurement may be made of the fluid. 
     An additional advantage of the present invention is the utilization of current fuel dispenser components to provide the vacuum means for the air separation system. Currently, many fuel dispensers manufactured today include a vapor recovery system. The vapor recovery system includes a vapor recovery pump for removing fuel vapors from a vehicle&#39;s fuel tank, dispenser nozzle, or surrounding area during refuelling. In one embodiment of the present invention, the vapor recovery pump provides the vacuum means for the air separation system. The advantage of using an existing vapor recovery pump as the vacuum means allows for the present invention to be installed in current fuel dispenser designs without installing additional vacuum means for the air separation system. Therefore, the cost of installation and manufacturing is reduced. 
     Another advantage of the present invention is the ability to cease application of vacuum to the air separation system when gas is not detected in the upper portion of the centrifugal separator. 
     Yet another advantage of the present invention is the presence of a by-pass valve which redirects de-aerated fuel back to the centrifugal separator. In one particular embodiment, a de-aerated fuel sensing means detects the presence of dissolved gases within the de-aerated fuel. When dissolved gases are detected, the by-pass valve redirects de-aerated fuel back to the centrifugal separator so that the detected dissolved gasses can be sepdrated from the fuel. Through possible repeated cycles, only fluid which contains dissolved gasses below a predetermined level or below the level of detection of the de-aerated fuel sensing means will be allowed to proceed past the by-pass valve. Consequently, the fuel dispenser will only dispense fuel which has first been properly de-aerated prior to being volumetric measured by a pump/meter unit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a sectional view of a fuel dispenser incorporating the present invention; and 
     FIG. 2 is a sectional view of an air separator system of the present invention. 
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and particularly to FIG. 1, there is shown a fuel dispenser  10  which incorporates the present invention. Fuel dispenser  10  includes a dispenser tank  12 . A fluid pump, fuel pump/meter unit  14 , when activated, pumps fuel from fuel tank  12  through fuel supply conduit  15  and fuel conduit  16  to hose  18 . Hose  18  is connected to nozzle  24 . Nozzle  24  contains handle  26  and lever  28 . Nozzle  24  also contains an outlet  30 , from where fuel is dispensed. A plurality of apertures are disposed annularly around nozzle  24  near outlet  30  and form inlet port  31 . 
     Vapor recovery system  34  includes vacuum pump  36 , vapor recovery conduit  38 , and dispenser tank  12 . During the operation of vapor recovery system  34 , vacuum pump  36  removes vapors from the environment directly outside of inlet port  31 . The vapors are evacuated through hose  18  under negative pressure generated by vacuum pump  36 . The collected or recovered vapors proceed through vapor recovery conduit  38 , passing through vacuum pump  36  and onto the dispenser tank  12 . Hose  18  contains an inner fuel hose surrounded by an outer vapor recovery hose (not shown). 
     During the operation of fuel dispenser  10 , fuel is dispensed from dispenser tank  12  through fuel conduits  15 ,  16  through the inner fuel hose of hose  19  and out of nozzle  24  through outlet  30 . In addition, fuel vapor is evacuated through inlet  31  through outer vapor recovery hose and into vapor recovery conduit  38 . 
     Referring now to FIG. 2, there is shown air separator system  42  of the present invention. Air separator system  42  contains a gas separator such as centrifugal separator  44 . Centrifugal separator  44  has an upper portion  46  with gas outlet  48 . Centrifugal separator  44  also contains separator fuel inlet  50  and separator fuel outlet  52 . Fuel conduit  16  connects separator fuel outlet  52  to pump/meter  14 . Fuel supply conduit  15  connects separator fuel inlet  50  to dispenser tank  12 . 
     Gas conduit S 4  connects gas outlet  48  Lo gas valve  56 . Gas conduit  54  joins gas valve  56  to vacuum pump  36 . Separator gas sensing means  58  is operatively associated with separator upper portion  46  and contains a separator gas sensor. A mechanical, electrical, or electronic means, such as gas controller  60 , is operatively associated with gas valve  56  and gas sensing means  58  by lines  62  and  64  respectively. 
     De-aerated fluid gas sensing means  66  is located in line between pump/meter unit  14  and by-pass valve  68 . Aerated fluid gas sensing means comprises a de-aerated fluid gas sensor. De-aerated fluid gas sensor means  66  and by-pass valve  68  are operatively associated with gas controller  60  by lines  70  and  72  respectively. By-pass conduit  74  connects by-pass valve  68  to supply fuel conduit  15 . 
     During the operation of the present invention, pump/meter  14  pumps fuel from dispenser tank  12  through fuel supply conduit  15  into centrifugal separator  44 . The interior of centrifugal separator  44  causes the fuel to spin, as depicted by line  76 . Centrifugal separator  44  separates or liberates dissolved gas from the fuel to produce de-aerated fuel. 
     The de-aerated fuel exits centrifugal separator  44  through separator fuel outlet  52  and proceeds through fuel conduit  16  into pump/meter inlet  78 . Pump/meter  14  both pumps fuel from dispenser tank  12 , and volumetrically measures the amount of fuel to be dispensed by fuel dispenser  10 . 
     Pump/meter unit  14  measures the volume of de-aerated fuel which is pumped. For example, pump/meter unit  14  can be a reciprocating electromechanical piston meter with a sliding mechanical piston. The pump/meter calculates volume by using the known volume of the piston cylinder and counting the number of strokes the piston reciprocates within the cylinder. 
     De-aerated fuel exits pump/meter  14  through pump/meter outlet  80  and proceeds past de-aerated fluid gas sensing means  66 . De-aerated fluid gas sensing means  66  detects the presence of dissolved gasses within the de-aerated fuel or fluid. De-aerated fluid gas sensing means  66  sends a signal through line  70  to gas controller  60  to indicating the presence of dissolved gasses. When gas controller  60  receives the signal from de-aerated gas sensing means  66  indicating the presence of dissolved gas, gas controller  60  sends a signal through line  72  to by-pass valve  68 . By-pass valve  68 , upon receiving the signal from gas controller  60 , redirects de-aerated fuel from fuel conduit  16  to by-pass conduit  74 . Consequently, de-aerated fluid in which dissolved gasses are still present, as detected by de-aerated fluid gas sensing means  66 , is returned to centrifugal separator  44  through fuel supply conduit  15 . This cycle is repeated until the presence of dissolved gasses is no longer detected by de-aerated fluid gas sensing means  66  or the quantity of dissolved gasses is below a predetermined value. By-pass valve  68  and by-pass conduit  74  provide quality control to assure only properly de-aerated fluid is measured by pump/meter  14 . 
     Dissolved gasses, which are separated in centrifugal separator  44  from liquid fuel proceeds into the centrifugal separator upper portion  46 . Vacuum pump  36  provides a vacuum to centrifugal separator upper portion  46 . Dissolved gasses proceed under a vacuum or negative pressure through gas conduit  54  in the direction of arrow  82  and pass through gas valve  56 . Separator gas sensing means  58  detects the presence of liberated dissolved gasses within centrifugal separator upper portion  46 . Upon sensing liberated dissolved gasses, separator gas sensing means  58  sends a signal through line  64  to gas controller  60 . When gas controller  60  receives a signal from separator gas sensing means  58  indicate the presence of liberated dissolved gasses, gas controller  60  sends a signal through line  62  to gas valve  56 . Gas valve  56 , upon receiving a signal from gas controller  60 , opens gas valve  56  allowing gas to be evacuated from separator upper portion  46 . Conversely, in the absence of detected liberated gas in separator upper portion  46 , gas controller  60  sends a signal through line  62  to close gas valve  56  whereby ceasing the vacuum applied to centrifugal separator upper portion  46 . 
     The liberated dissolved gasses from the liquid fuel can be stored along with fuel vapor recovered by the vapor recovery system  34  in dispenser tank  12 . The vacuum means for removing gas from centrifugal separator  44  is vacuum pump  36  which may also used in vapor recovery system  34 . Alternatively, other vacuum means may be utilized in the air separator system  42 . In other words, vacuum means does not necessarily have to be the same vacuum pump  36 , which is used in vapor recovery system  34 . In addition, a separate pump and meter may be used rather than a single pump/meter unit  14 . 
     While this invention has been described as having a preferred design, 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.