Fluid characterization system with integrated density compensation
An integrated densitometer-compensator system for providing a digital indication of the dielectric value and density of a fluid in a tank includes a dielectric capacitive measuring device, a vibrating spool fluid density measuring device, a signal processor, a power supply, and a remote computing device. The signal processor produces a digital signal representing the dielectric value and density of the fluid, and includes a serial driver that transmits the digital signal as a serial word by modulating a carrier signal. An unshielded interface cable transmits the serial word, which can contain a unique identifier, and also provides power to the system. Transmission can be electrically, optically, or wirelessly. The exemplary system measures aviation fuel characteristics in fuel tanks onboard an aircraft.
1. A system for producing a modulated carrier signal that is representative of a dielectric value and a density of a fluid, the system comprising:
a chassis configured to be immersed in the fluid;
a first device configured to produce a first signal that is indicative of the dielectric value of the fluid;
a second device comprising a densitometer spool configured to produce a mechanical response that is indicative of the density of the fluid, the second device configured to produce a second signal that is indicative of the density of the fluid; and
a signal processor comprising a serial driver, the signal processor in operable communication with both the first device and the second device, the signal processor configured to calculate a digital signal that is indicative of the dielectric value and the density of the fluid;
wherein:
the first device, the second device, and the signal processor are disposed within the chassis; and
the serial driver is configured to:
produce a serial word that is representative of the digital signal;
modulate a carrier signal; and
communicate the modulated carrier signal externally of the system;
the modulated carrier signal is representative of the serial word.
2. The system of claim 1 , wherein:
the first device is comprised of:
a compensator configured to produce an electrical capacitance signal that is indicative of the dielectric value of the fluid; and
a compensator signal conditioner electrically connected to the compensator, configured to produce an electrical signal that is indicative of the electrical capacitance signal; and
the second device further comprises:
a densitometer signal conditioner electromagnetically connected to the densitometer spool, configured to produce an electrical signal that is indicative of the mechanical response; and
the signal processor further comprises a microprocessor configured to:
store a plurality of correction factors representing the mechanical response; and
calculate the digital signal that is representative of the dielectric value and the density of the fluid.
3. The system of claim 2 , further comprising a power supply, the power supply configured to provide electrical power to the compensator signal conditioner, the densitometer signal conditioner, the microprocessor, and the serial driver.
4. The system of claim 3 , further comprising an energy storage device, wherein the energy storage device is configured to store electrical energy.
5. The system of claim 3 , further comprising an interface cable, the interface cable configured to transmit the serial word.
6. The system of claim 5 , wherein:
the interface cable is comprised of a two-wire electrical pair;
the serial driver is configured to transmit the serial word over the two-wire electrical pair; and
the power supply is configured to receive electrical input power over the two-wire electrical pair.
7. The system of claim 5 , wherein:
the interface cable is comprised of an optical fiber;
the serial driver is configured to transmit the serial word over the optical fiber; and
the power supply is configured to receive optical input power over the optical fiber.
8. The system of claim 7 , wherein:
the serial driver is configured to transmit the serial word utilizing a first wavelength of light; and
the power supply is configured to receive optical input power utilizing a second wavelength of light.
9. The system of claim 3 , wherein the power supply is configured to:
receive electrical input power via the interface cable;
convert the electrical input power into electrical power; and
provide the electrical power to the compensator signal conditioner, the densitometer signal conditioner, the microprocessor, and the serial driver.
10. The system of claim 3 , wherein the power supply is configured to:
receive optical input power via the interface cable;
convert the optical input power into electrical power; and
provide the electrical power to the compensator signal conditioner, the densitometer signal conditioner, the microprocessor, and the serial driver.
11. The system of claim 2 , wherein the serial driver is configured to transmit the serial word wirelessly.
12. The system of claim 2 , wherein the serial driver is configured to transmit the serial word utilizing digital encoding selected from the group consisting of: frequency shift keying, amplitude shift keying, phase shift keying.
13. The system of claim 2 , wherein:
the serial driver has an identification code; and
the serial word further comprises the identification code.
14. A system for producing a modulated carrier signal that is representative of a dielectric value and a density of a fluid in a tank, the system comprising:
a remote computing device;
a chassis configured to be disposed in the tank;
a first device configured to produce a first signal that is indicative of the dielectric value of the fluid;
a second device comprising a densitometer spool configured to produce a mechanical response that is indicative of the density of the fluid, the second device configured to produce a second signal that is indicative of the density of the fluid; and
a signal processor comprising a serial driver, the signal processor electrically connected to both the first device and the second device, the signal processor configured to:
produce a first electrical signal that is representative of the first signal;
produce a second electrical signal that is representative of the second signal;
calculate a digital signal that is representative of the dielectric value and the density of the fluid;
produce, via the serial driver, a serial word that is indicative of the digital signal; and
modulate, via the serial driver, a carrier signal, wherein the modulated carrier signal is representative of the serial word;
a power supply configured to receive power input from the remote computing device; and
an interface cable configured to:
transmit the serial word from the serial driver to the remote computing device; and
transmit input power from the remote computing device to the power supply;
wherein:
the first device, the second device, and the signal processor are disposed within the chassis.
15. The system of claim 14 , wherein:
the interface cable further comprises a two-wire pair; and
the power supply is configured to receive electrical power input from the remote computing device via the two-wire pair; and
the signal processor is configured to transmit the serial word to the remote computing device via the two-wire pair.
16. The system of claim 14 , wherein:
the interface cable further comprises an optical fiber; and
the power supply is configured to receive optical power input from the remote computing device via the optical fiber; and
the signal processor is configured to transmit the serial word to the remote computing device via the optical fiber.
17. The system of claim 14 , wherein the signal processor is configured to transmit the serial word utilizing digital encoding selected from the group consisting of: frequency shift keying, amplitude shift keying, phase shift keying.
18. The system of claim 14 , wherein:
the signal processor is configured to transmit the serial word utilizing a first wavelength of light; and
the power supply is configured to receive optical input power utilizing a second wavelength of light.
19. A method for using a system to produce a modulated carrier signal that is representative of a dielectric value and a density of a fluid within a tank, the system comprising a first device, a second device that comprises a densitometer spool configured to produce a mechanical response that is indicative of the density of the fluid, and a signal processor disposed within a chassis, the signal processor comprising a serial driver, the chassis configured to be disposed within the tank, the method comprising:
producing a first signal with the first device that is indicative of the dielectric value of the fluid;
producing a second signal with the second device that is indicative of the density of the fluid;
calculating, with the signal processor, a digital signal that is indicative of the dielectric value and the density of the fluid, based on the first signal and the second signal;
producing, with the serial driver, a serial word that is representative of the digital signal;
modulating, with the serial driver, a carrier signal; and
transmitting, from the serial driver, the digital signal externally of the signal processor;
wherein the modulated carrier signal is representative of the serial word.
20. The method of claim 19 , further comprising:
transmitting, by an interface cable, the modulated carrier signal.