Fluent material handling – with receiver or receiver coacting mea – Diverse fluid containing pressure filling systems involving... – Filling with exhausting the receiver
Reexamination Certificate
2000-08-04
2001-12-25
Jacyna, J. Casimer (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Diverse fluid containing pressure filling systems involving...
Filling with exhausting the receiver
C141S007000, C141S094000, C141S290000
Reexamination Certificate
active
06332483
ABSTRACT:
BACKGROUND
Systems for dispensing fuel into vehicles, e.g. at gasoline stations, typically employ a coaxial hose, which, in so-called inverted arrangement, has an outer conduit for delivery of fuel to the vehicle and an inner conduit for recovery of fuel vapors displaced from the vehicle tank. Recent field testing by the California Air Resources Board (CARB) of vacuum assist vapor recovery systems for use in fuel dispensing systems uncovered a problem with the inverted coaxial hose. They found that the internal vapor hose can kink during normal operation, causing substantial blockage of the vapor return pathway. Once kinked, these hoses tend to remain in a tube-collapsed condition, thus permanently reducing the cross sectional area of the vapor flow path.
Vacuum assist systems which employ a variable speed vane pump, or other flow control device mounted in the dispenser, use the electronic pulses related to the liquid gasoline flow rate to control the vane pump speed or the orifice size of a variable orifice restrictor. Using this technique, the volumetric rate of vapor recovery is maintained in proportion to the rate of liquid gasoline delivery.
A kink in the vapor hose will act to restrict vapor flow, thus changing the absolute pressure on the inlet side of the vapor flow control device. The reduction in pressure results in a reduction in throughput for both the vane pump and the variable orifice flow control device. A kink in the vapor hose can therefore result in escape of gasoline vapor in the vehicle tank fillpipe to the extent that the vapor recovery throughput is reduced at the flow control device.
In practice, the detection of a damaged vapor hose in the service station is not easy, since the outer hose might not show any physical sign of kinking. This type of defect can only be found through extensive testing or by a process of elimination of other vapor recovery related components.
SUMMARY
According to one aspect of the invention, a method for monitoring vapor-to-liquid flow rate in a fuel dispensing system with a vacuum assisted vapor recovery system having a coaxial hose with an outer fuel conduit for delivery of fuel and an inner vapor conduit for recovery of vapor comprises the steps of: determining vapor flow rate in the inner vapor conduit; issuing a signal indicative of the vapor flow rate; determining liquid fuel flow rate in the outer fuel conduit; issuing a signal indicative of the liquid fuel flow rate; comparing the signal indicative of the vapor flow rate and the signal indicative of the liquid fuel flow rate; and, when vapor-to-liquid flow rate is outside a predetermined range, issuing a signal.
Preferred embodiment of this aspect of the invention may include the following additional features. The method comprises the steps of: issuing the signal to adjust flow of vapor; comparing the signal indicative of the vapor flow rate and the signal indicative of the liquid fuel flow rate; and, if vapor-to-liquid flow rate remains outside a predetermined range, issuing a signal to further adjust flow of vapor. The method comprises the step of issuing the signal to adjust flow of vapor.
According to another aspect of the invention, a vacuum assist vapor recovery system for a fuel dispensing system having a coaxial hose with an outer fuel conduit for delivery of fuel and an inner vapor conduit for recovery of vapor comprises: an indicator assembly for providing indication of vapor flow reduction in the inner vapor conduit, the indicator assembly comprising a detector element in communication with the inner vapor conduit for detection of vapor flow within the inner vapor conduit and an indicator element of vapor flow for indication of vapor flow and vapor flow reduction within the inner vapor conduit detected by the detector element, the detector element comprising a Venturi device disposed in communication with the inner vapor conduit, a diaphragm responsive to the pressure between the Venturi throat and the upstream inner vapor passageway, and a magnet associated with, i.e. reflecting the movement of, the diaphragm, and the indicator element comprising a signal indicative of the vapor flow rate from a Hall Effect device.
According to still another aspect of the invention, a fuel dispensing system with a vacuum assisted vapor recovery system having a coaxial hose with an outer fuel conduit for delivery of fuel and an inner vapor conduit for recovery of vapor and further comprises an indicator assembly for providing indication of restriction of flow cross-section for the inner vapor conduit, the indicator assembly comprising a detector element in communication with the inner vapor conduit for detection of vapor flow within the inner vapor conduit and an indicator element of vapor flow for indication of vapor flow and detection of vapor flow reduction within the inner vapor conduit detected by the detector element, the detector element comprising a Venturi device disposed in communication with the inner vapor conduit, a diaphragm responsive to the pressure between the Venturi throat and the upstream inner vapor passageway, and a magnet associated with, i.e. reflecting the movement of, the diaphragm, and the indicator element comprising a signal indicative of the vapor flow rate from a Hall Effect device.
According to another aspect of the invention, a vacuum assist vapor recovery system, e.g. in or for a fuel dispensing system, having a coaxial hose with an outer fuel conduit for delivery of fuel and an inner vapor conduit for recovery of vapor comprises an indicator assembly for providing indication of vapor flow reduction in the inner vapor conduit, e.g., due to restriction of flow cross-section in the inner vapor conduit or failure of a vacuum pump or other vacuum control device, the indicator assembly comprising a detector element in communication with the inner vapor conduit for detection of vapor flow within the inner vapor conduit and an indicator element of vapor flow for indication of vapor flow within the inner vapor conduit detected by the detector element.
Preferred embodiments of the invention may include one or more of the following additional features. The indicator assembly further comprises a housing defining a chamber in communication with the inner vapor conduit, a paddle mounted to pivot in the chamber between a first position indicating relatively low or no flow and a second position indicating relatively higher flow, spring means biasing the paddle toward the first position, and a window for viewing into the chamber from external of the housing, the paddle having a first end portion disposed in a flow of vapor through the inner vapor conduit, the first end portion being moved from the first position toward the second position by vapor flow in the inner vapor conduit for detection of vapor flow within the inner vapor conduit, and the paddle having a second end portion disposed in view of the window, the second end portion being moved from the first position toward the second position in response to movement of the first end portion in detection of flow of vapor for indication of vapor flow within the inner vapor conduit. The indicator assembly further comprises a housing defining a chamber in communication with the inner vapor conduit, a paddle wheel comprising a body with a plurality of paddles extending therefrom generally radially in a plane of rotation, the paddle wheel being mounted to rotate in the chamber in response to flow of vapor in the inner vapor conduit, and a window for viewing into the chamber from external of the housing, at any time, one or more of the plurality of paddles being disposed in a flow of vapor through the inner vapor conduit, the one or more paddles being moved and the paddle wheel being rotated by vapor flow in the inner vapor conduit for detection of vapor flow within the inner vapor conduit, and one or more other of the plurality of paddles being disposed in view of the window, the one or more other of the plurality of paddles being moved relative to the window in response to movement of the one or more paddles
Fish & Richardson P.C.
Healy Systems, Inc.
Jacyna J. Casimer
LandOfFree
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