Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F9/00—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine

Definitions

• This invention relates to the measurement of fuel flow to a fuel pump of the type that receives more fuel than it may deliver and in which provision is made for return of the excess fuel.
• the present invention is directed to overcoming one of more of the problems as set forth above.
• a fuel rate measuring system for use with a fuel consuming apparatus of the type which receives more fuel than is consumed with the excess recirculated.
• the measuring system includes an inlet for receipt of liquid fuel, a flow meter connected to the inlet for measuring and indicating the fuel flow from the inlet and an outlet which is to be connected to the apparatus and to the flow meter for receiving fuel from the latter and delivering it to the former.
• a fuel recirculating line has one end connected to the fuel consuming apparatus to receive excess fuel and air entrainment therefrom and another end returned to the system between the flow meter and the system outlet.
• the recirculating line and the outlet define a closed, constant volume path.
• a gas vent is disposed in the path for venting gas therein to the atmosphere while containing liquid fuel within the path.
• a method for determining fuel flow to such a fuel consuming apparatus provided with a fuel pump which comprises the step of measuring the flow of fuel to the fuel pump at a predetermined point in a fuel line while returning the excess flow to the fuel line between the fuel pump at the point in closed, constant volume path.
• Fig. 1 is a schematic of a typical prior art fuel flow measuring system
• Fig. 2 is a schematic of a fuel flow measuring system made according to the present invention.
• Fig. 3 is a side elevation of part of the fuel flow system.
• FIG. 1 A typical prior art fuel flow measuring system is illustrated in Fig. 1 and is seen to include an inlet 10 which may be connected to a fuel tank (not shown) to recieve fuel therefrom.
• the inlet is connected to a conventional pressure-regulating valve 12 which provides fuel at some regulated pressure to a conventional flow meter 14. Readings on fuel flow are taken from the flow meter 14 and dependent upon system sophistication, can be taken visually or recorded through the use of conventional recorders.
• Fuel exiting the flow meter 14 is then provided to a second pressure regulating valve 16 and then to a float valve 18 in an open ended tank 20.
• the valve 18 is intended to maintain a constant level of fuel within the tank 20 although, as will be seen, it is incapable of doing so.
• Fuel from the tank 20 is directed through a heat exchanger 22 to emerge therefrom at some desired temperature and enter a fuel pump 24.
• the fuel pump 24 may be of the type used for directing fuel under pressure to each of six cylinders of, for example, a fuel injected, internal combustion engine, via lines 26.
• the improved fuel flow rate measuring system of the present invention is shown in Figs. 2 and 3 and is seen to include an inlet 30 which may be connected to a source of fuel such as a fuel tank or the like. Fuel from the inlet 30 is directed to a first pressure regulating valve 32 and then to a flow meter 34. From the flow meter 34, fuel is directed to a second pressure regulating valve 36.
• a source of fuel such as a fuel tank or the like.
• Fuel from the inlet 30 is directed to a first pressure regulating valve 32 and then to a flow meter 34. From the flow meter 34, fuel is directed to a second pressure regulating valve 36.
• the system of the invention may be identical to that of the prior art.
• the second pressure regulating valve 36 directs fuel to a heat exchanger 38 similar or identical to the heat exchanger 22 and then to a fuel pump 40 of the same type as the fuel pump 24. Excess fuel from the pump 40 is returned via a line 42 to a point between the flow meter 34 and the system outlet 44 to the pump 40, and specifically, between the second pressure regulating valve 35 and the heat exchanger 38.
• the return line 42 and all components downstream of the flow meter 34 define a closed, constant volume flow path for the fuel. The only fuel moving out of the path is that removed by the pump 40 and directed to the engine or the like. This fuel is replaced by fuel flowing through the flow meter 34 so that in essence, the system provides for direct measurement of fuel consumption rather than indirect measurement as in the prior art.
• the system is completed by a gas venting means generally designated 46 in the return line 42 by which any gas in the closed path is vented.
• the gas venting means 46 will be described in greater detail.
• the same includes the vertically directed standpipe 48,
• the upper end of the standpipe 48 is closed by a conventional air vent valve 50 which, as is well know, will open to allow gas at the upper end of the standpipe 48 to exit the same until all gas is gone and then will close to prevent any liquid from exiting the standpipe 48.
• Fuel from the flow meter 34 enters the second pressure regulating valve 36 and then is directed to the lower part of the standpipe 48 via a tee 52. By means of a connection (not shown) to the lowest end of the standpipe 48, fuel is then conveyed to the heat exchanger 38.
• a second tee 54 in the standpipe 48 receives the return line 42.
• a third tee 56 mounts a pressure gauge 58.
• a sight glass 60 Between the tee 56 and the valve 50 is a sight glass 60.
• the overall height of the standpipe 48 is limited only by the least system pressure as determined by the minimum setting on the second pressure regulating valve 36.
• the pressure setting must be such as to drive the fuel to the top of the standpipe 48 so that any gas above the fuel level will be driven out of the air vent valve 50.
• the presence of fuel or gas bubbles at this level can be checked by the sight glass 60 and the system pressure can be checked by the pressure gauge 58.
• the first pressure regulating valve 32 may be dispensed with in favor of any suitable constant pressure input to the system capable of providing the desired input pressure.
• an elevated reservoir containing the fuel to be consumed could be employed as an alternate.
• any trapped air or gas in the fuel system 40 passes through the return line 42 to the standpipe 48 at which time it is vented from the system by operation of the air vent valve 50.
• System pressure is adjusted through operation of the second pressure regulating valve to achieve the desired fuel pump inlet pressure at the fuel pump 40.
• the valve 50 will close thereby providing the constant volume, closed system.
• This system then provides for accuracy of fuel rate measurement as the fuel, is being driven into a constant volume thereby eliminating all variations in fuel flow rate for a given fuel delivery by the fuel pump 40. And because the volume remains constant for all operating conditions of the fuel consuming apparatus, response to a change in fuel consumption is immediate.

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• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Volume Flow (AREA)
• Telephone Set Structure (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=22147782

Family Applications (1)

Country Status (6)

Cited By (1)

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• 1979
  • 1979-11-09 JP JP50008279A patent/JPS56501498A/ja active Pending
  • 1979-11-09 GB GB8107687A patent/GB2076888B/en not_active Expired
  • 1979-11-09 WO PCT/US1979/000974 patent/WO1981001462A1/en not_active Ceased
  • 1979-11-09 EP EP19800900026 patent/EP0039673A1/en not_active Withdrawn
• 1980
  • 1980-07-07 CA CA000355628A patent/CA1141991A/en not_active Expired
  • 1980-10-10 BE BE1/9982A patent/BE885626A/fr not_active IP Right Cessation

Non-Patent Citations (1)

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