1. Fill-level indicator for use in a liquefied petroleum gas tank, comprising:
an array of optical detectors (9) attached to a mount, vertically spaced apart from one another and distributed inside the tank (2) over the height of the latter, each detector including a light source (10) and a receiver (12), and
means (17) for feeding power to the light sources of the various detectors (9), for processing the signals arriving at the various receivers (12) and for transmitting signals to a gauge (20) displaying the fill-level of the liquefied gas,
characterized in that the mount and the detectors placed on it are positioned in a casing (16) which is highly transparent to the light beams emitted by the light sources (10) and that a synthetic resin (13) which is highly transparent to the light beams emitted by the light sources (10) is poured between one surface of the said casing and the detectors for encapsulating the mount and the detectors in such fashion that the surface of the resin facing the detectors (9) reflects a light beam emitted by the corresponding light source (10) toward the associated receiver (12).
2. Fill-level indicator as in claim 1, characterized in that the material constituting the casing has a refractive index very close to that of the resin.
3. Fill-level indicator as in claim 1 or 2, characterized in that the resin used is an epoxy resin.
4. Fill-level indicator as in one of the claims 1 to 3, characterized in that the casing (16) consists of polycarbonate.
5. Fill-level indicator as in one of the claims 1 to 4, characterized in that the casing (16) is in the form of a U-shaped profile, that each leg (23) of the U is provided on its inside with a longitudinal groove (25), whereby the two grooves are designed to accept the mount (8) with the detectors (9) in such fashion that it extends parallel to the base (24) of the casing.
6. Fill-level indicator as in one of the claims 1 to 5, characterized in that the mount (8), the resin (13) and, where applicable, the casing (16) are flush-mounted in a retaining head (26) designed to be attached to the tank (2).
7. Fill-level indicator as in claim 6, characterized in that the retaining head (26) is a metal head equipped with an annular flange and attached to the tank (2) by means of screws.
8. Fill-level indicator as in claim 6 or 7, characterized in that an insulated wire conduit (28) is installed in the retaining head (26).
9. Fill-level indicator as in one of the claims 1 to 8, characterized in that the mount (8) consists of a printed circuit board.
10. Fill-level indicator as in one of the claims 1 to 9, characterized in that the means (17) for supplying power to the light sources and for processing the signals include a microprocessor or a microcontroller.
11. Fill-level indicator as in one of the claims 1 to 10, characterized in that the means (17) for processing the signals perform a smoothing of the shift value of the gauge (20) between the measurements of two neighboring detectors (9) by simulating intermediate measurements between two actual measuring points, interpolating a mean gas consumption during an average time period.
12. Fill-level indicator as in one of the claims 1 to 11, characterized in that the signal processing means (17) include a filtering of the change of state of the detectors (9) by the integration of a time lag during which no detection variation is to be registered.
13. Fill-level indicator as in one of the claims 1 to 12, characterized in that, when used in an automobile tank (12), the signal processing means (17) are connected at one end to a distribution panel (19) for feeding electric current to the engine of the vehicle and at the other end to a solenoid valve (6) mounted on the filler unit of the tank, for the purpose of permitting the opening of the solenoid valve only when the engine is stopped and the fill level is below a specific point, that being 80% of the maximum capacity of the tank represented by the detector in the uppermost position.
14. Fill-level indicator as in one of the claims 1 to 13, characterized in that the signal processing means (17) perform a detector test function within a specific periodic cycle.
15. Fill-level indicator as in claim 14, characterized in that in the event of a failure of the maximum-fill-level detector (9) its functions are automatically transferred to the next lower detector, or the filling of the tank is rendered impossible by keeping the solenoid valve closed.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. An antenna system installation comprising a towersupport structure, and an antenna structure mounted on said towersupport structure, said antenna structure comprising:
a plurality of antenna elements;
a plurality of power amplifiers, each power amplifier being operatively coupled with one of said antenna elements and mounted closely adjacent to the associated antenna element, such that no appreciable power loss occurs between the power amplifier and the associated antenna element;
each said power amplifier comprising a relatively low power, relatively low cost per watt linear power amplifier chip;
a first RF to fiber transceiver mounted on said towersupport structure and operatively coupled with said antenna structure; and
a second RF to fiber transceiver mounted adjacent a base portion of said towersupport structure and coupled with said first RF transceiver by an optical fiber cable.
2. A method of installing an antenna system on a towersupport structure, said method comprising:
mounting a plurality of antenna elements arranged in an antenna array on said towersupport structure;
coupling a power amplifier comprising a relatively low power, relatively low cost per watt linear power amplifier chip with each of said antenna elements mounted closely adjacent to the associated antenna element, such that no appreciable power loss occurs between the power amplifier and the associated antenna element; and
mounting a first RF to fiber transceiver on said towersupport structure, and coupling said first RF to fiber transceiver with said antenna structure; and mounting a second RF to fiber transceiver adjacent a base portion of said towersupport structure, and coupling said second RF to fiber transceiver with said first RF to fiber transceiver by an optical fiber cable.