Patent US1351338A successfully refreshed from Google Patents.
EP0260788A2
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EP
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Residential fuel-oil level reporting and alarm system
Assignee: Scully Signal Co
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Filing: 1987-06-26
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Granted: —
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Expires: 2007-06-26
Abstract
Abstract An automatic reorder and alarm system for use with residential fuel-oil tanks which sends reorder and alarm data to a central station over the direct-dial telephone network when the fuel-oil level in the tank falls below a predetermined value or when an alarm situation, such as low temperature, occurs at the tank location. An inexpensive sensor/sending unit located at each customer tank includes a simple sensor which mounts on either the tank or an existing fuel-oil level gauge, a microcontroller circuit and a modem circuit. The microcontroller circuit uses a simple low-stability oscillator as a reference for internal operations and for modem transmission frequencies. Because the oscillator frequency cannot be precisely determined due to component tolerances and has a substantial amount of drift, a special data transmission format is used for data transmission over the telephone lines between the microcontroller and the central station. The data format consists of a selected pattern of mark and space signals in which each mark signal consists of a predetermined number of cycles of an oscillating signal whose frequency is determined by the internal modem oscillator and each space signal is an equivalent time period without a signal. At the receiver the bit time duration is determined by averaging bit times in a predetermined bit pattern header.
Inventors
- 👤 John D Knight
- 👤 Frank H Banks
- 👤 Barry S Sunray
- 👤 Robert D Shapiro
- 👤 Andrew Mitchell
- 👤 Robert A Defrancesco
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 21:36
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/30; G01F23/32; G01F23/36; H; H04; H04M; H04M11/00; H04M11/002
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
140 words
In a system for reporting the fuel-oil level in a residential tank to a central location, a sensor unit located near said tank, said sensor unit comprising: means located at said tank location for generating a fuel-oil level sense signal, detector means responsive to said sense signal for producing a reorder signal when the fuel-oil in said tank reaches a predetermined level, an oscillator for generating a single frequency output signal, said output signal having a frequency variation about said single frequency, and controller means responsive to said reorder signal and to said oscillator output signal for transmitting a data word encoded by digital bits consisting of pulses of said single frequency to said central location, said data word comprising a fixed, predetermined header pattern of bits, followed by a plurality of data bits followed by a checksum bit pattern.
Claim 2
Dependent Claim
140 words
In a system for reporting the fuel-oil level in a residential tank to a central location, a sensor unit located near said tank, said sensor unit comprising: means located at said tank location for generating a fuel-oil level sense signal, detector means responsive to said sense signal for producing a reorder signal when the fuel-oil in said tank reaches a predetermined level, an oscillator for generating a single frequency output signal, said output signal having a frequency variation about said single frequency, and controller means responsive to said reorder signal and to said oscillator output signal for transmitting a data word encoded by digital bits consisting of pulses of said single frequency to said central location, said data word comprising a fixed, predetermined header pattern of bits, followed by a plurality of data bits followed by a checksum bit pattern.
Claim 3
Dependent Claim
56 words
In a fuel-oil level reporting system, the sensor unit according to Claim 1 wherein said digital bits consist of a mark bit comprising a predetermined number of cycles of said single frequency signal and a space bit comprising a period of time equal to the time period of said mark in which no signal is transmitted.
Claim 4
Dependent Claim
25 words
In a fuel-oil level reporting system, the sensor unit according to Claim 2 wherein said header pattern comprises a predetermined number of sequential mark bits.
Claim 5
Dependent Claim
55 words
In a fuel-oil level reporting system, the sensor unit according to Claim 1 wherein said data bits comprise a plurality of status bits, including at least one bit indicating the status of said reorder signal and a plurality of identification number bits, said identification number bits representing an identification number unique to said sensor unit.
Claim 6
Dependent Claim
32 words
In a fuel-oil level reporting system, the sensor unit according to Claim 1 wherein said checksum bits encode a checksum derived from logically combining said identification number bits and said checksum bits.
Claim 7
Dependent Claim
21 words
In a fuel-oil level reporting system, the sensor unit according to Claim 1 wherein said generating means is a capacitive sensor.
Claim 8
Dependent Claim
28 words
In a fuel-oil level reporting system, the sensor unit according to Claim 6 wherein said detector means compares the capacitance of said capacitive sensor to a known capacitance.
Claim 9
Dependent Claim
20 words
In a fuel-oil level reporting system, the sensor unit according to Claim 1 wherein said oscillator is a resistance/capacitance oscillator.
Claim 10
Dependent Claim
21 words
In a fuel-oil level reporting system, the sensor unit according to Claim 1 wherein said oscillator is an inexpensive crystal oscillator.
Claim 11
Dependent Claim
33 words
In a fuel-oil level reporting system further having a mechanical fuel-oil level gauge, the sensor unit according to Claim 1 wherein said generating means is an electrical switch controlled by said mechanical gauge.
Claim 12
Dependent Claim
33 words
In a fuel-oil level reporting system, the sensor unit according to Claim 10 wherein said electrical switch is a magnetic reed switch which is controlled by a magnet attached to said mechanical gauge.
Claim 13
Dependent Claim
42 words
In a fuel-oil level reporting system, the sensor unit according to Claim 1 further comprising means for sensing additional alarm conditions and for generating an alarm signal when said condition occur and means for encoding said alarm signals into said data word.
Claim 14
Independent Claim
186 words
A system for reporting the fuel-oil level in a residential tank to a central location comprising: a sensor unit located near said tank, said sensor unit comprising: means located at said tank location for generating a fuel-oil level sense signal. detector means responsive to said sense signal for producing a reorder signal when the fuel-oil in said tank reaches a predetermined level, an oscillator for generating a single frequency output signal, said output signal having a frequency variation about said single frequency, controller means responsive to said reorder signal and to said oscillator output signal for transmitting a data word encoded by digital bits consisting of pulses of said single frequency output signal to said central location, said data word comprising a fixed, predetermined header pattern of bits, followed by a plurality of data bits followed by a checksum bit pattern, a receiving unit located at said central location comprising, means for receiving said data word, means responsive to said header bit pattern in said data word for determining the bit time duration by calculating the average time duration of the bits in said header pattern.
Claim 15
Independent Claim
186 words
A system for reporting the fuel-oil level in a residential tank to a central location comprising: a sensor unit located near said tank, said sensor unit comprising: means located at said tank location for generating a fuel-oil level sense signal. detector means responsive to said sense signal for producing a reorder signal when the fuel-oil in said tank reaches a predetermined level, an oscillator for generating a single frequency output signal, said output signal having a frequency variation about said single frequency, controller means responsive to said reorder signal and to said oscillator output signal for transmitting a data word encoded by digital bits consisting of pulses of said single frequency output signal to said central location, said data word comprising a fixed, predetermined header pattern of bits, followed by a plurality of data bits followed by a checksum bit pattern, a receiving unit located at said central location comprising, means for receiving said data word, means responsive to said header bit pattern in said data word for determining the bit time duration by calculating the average time duration of the bits in said header pattern.
Claim 16
Dependent Claim
62 words
A fuel-oil level reporting system according to Claim 13 wherein said digital bits consist of a mark bit comprising a predetermined number of cycles of said single frequency output signal and a space bit comprising a period of time equal to the time period of said mark in which no signal is transmitted and said header pattern comprises eight sequential mark bits.
Claim 17
Dependent Claim
51 words
A fuel-oil level reporting system according to Claim 13 wherein said data bits comprise a plurality of status bits, including at least one bit indicating the status of said reorder signal and a plurality of identification number bits, said identification number bits representing an identification number unique to said sensor unit.
Claim 18
Dependent Claim
36 words
A fuel oil level reporting system according to Claim 13 wherein said data bits comprise at least one bit indicating the status of an alarm signal indicating an alarm condition other than a low fuel-oil condition.
Claim 19
Dependent Claim
37 words
A fuel-oil level reporting system according to Claim 13 wherein said checksum bits encode a checksum derived from logically combining all bits sent in the entire transmission including said header bits, identification number bits and data bits.
Claim 20
Dependent Claim
17 words
A fuel-oil level reporting system according to Claim 13 wherein said generating means is a capacitive sensor.
Claim 21
Dependent Claim
17 words
A fuel oil level reporting system according to Claim 13 wherein said oscillator is a resistance/capacitance oscillator.
Claim 22
Dependent Claim
17 words
A fuel-oil level reporting system according to Claim 13 wherein said oscillator is an inexpensive crystal oscillator.
Claim 23
Dependent Claim
39 words
A fuel-oil level reporting system further having a mechanical fuel-oil level gauge, the sensor unit according to Claim 13 wherein said generating means is a magnetic reed switch which is controlled by a magnet attached to said mechanical gauge.
Claim 24
Dependent Claim
112 words
In a system for reporting the fuel-oil level in a residential tank to a central location, said tank having a mechanical level gauge attached thereto, said gauge comprised of a movable mechanical arm with a float attached thereto, said float and arm moving in response to changes in fuel-oil level, and an indicator vial located on the outside of said tank containing an indicator button attached to said arm, a sensor unit: a magnet attached to said indicator button, a magnetic reed switch located in close proximity to said gauge vial, said reed switch containing contacts which close to indicate a low-oil condition when said magnet moves close to said reed switch.
Claim 25
Dependent Claim
112 words
In a system for reporting the fuel-oil level in a residential tank to a central location, said tank having a mechanical level gauge attached thereto, said gauge comprised of a movable mechanical arm with a float attached thereto, said float and arm moving in response to changes in fuel-oil level, and an indicator vial located on the outside of said tank containing an indicator button attached to said arm, a sensor unit: a magnet attached to said indicator button, a magnetic reed switch located in close proximity to said gauge vial, said reed switch containing contacts which close to indicate a low-oil condition when said magnet moves close to said reed switch.
Claim 26
Dependent Claim
21 words
A sensor according to Claim 23 further comprising a clamp unit for slidably holding said reed switch on said indicator vial.
Claim 27
Dependent Claim
86 words
In combination, a sensor according to Claim 23, an oscillator for generating a single frequency output signal, said output signal having a frequency variation about said single frequency, and controller means responsive to said reorder signal and to said oscillator output signal for transmitting a data word encoded by digital bits consisting of pulses of said single frequency to said central location, said data word comprising a fixed, predetermined header pattern of bits, followed by a plurality of data bits followed by a checksum bit pattern.
References Cited (Backward Citations)
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