Drone for explosive gas atmospheres

Abstract

Drone (100) for explosive gas atmospheres, comprising propulsion means (110) comprising propellers (110a) connected to coaxial rotors (110b), and a pressurized enclosure (120) connected to the propulsion means (110) and comprising polymeric material with conductive fillers, wherein the pressurized enclosure (120) comprises a first cover (130), a central ring (140) and a second cover (150), wherein a first space (A) defined between the first cover (130) and the central ring (140) houses the drone control unit (100) for controlling at least the propulsion means, wherein a second space (B) defined in the central ring (140) houses the power electronics for powering the propulsion means, and wherein a third space (C) defined between the second cover (150) and the central ring (140) houses one or more control and data acquisition sensors.

Description

[0001] Drone for explosive gas atmospheres

[0002] DESCRIPTION

[0003] Object of the invention

[0004] The present invention relates to a drone for explosive gas atmospheres.

[0005] Background of the invention

[0006] CN115771628A describes a drone for coal mining, where drone design requirements are not as stringent as for refinery atmospheres.

[0007] The state of the art is required for a drone designed for explosive gas atmospheres that includes means to ensure the drone does not reach temperatures exceeding 200 degrees, thus allowing it to operate in the presence of, for example, 90% of the tabulated gases and that prevents the appearance of electrostatic sparks to avoid exposing risk elements to the potential mixture of explosive substances.

[0008] The present invention satisfies this demand.

[0009] Description of the invention

[0010] The present invention relates to a drone for explosive gas atmospheres. The drone includes design and operational safety features for operation in oil and gas facilities.

[0011] The main aspect of the invention relates to a drone for explosive gas atmospheres, comprising propulsion means comprising propellers connected to coaxial rotors, a pressurized casing connected to the propulsion means and comprising polymeric material with conductive charges, where the pressurized casing comprises a first cover, a central ring and a second cover, where a first space defined between the first cover and the central ring houses the drone control unit for controlling the propulsion means, where a second space defined in the central ring houses the power electronics for supplying the propulsion means and where a third space defined between the second cover and the central ring houses one or more control and data acquisition sensors.

[0012] In one example, the propulsion means comprise 4 coaxial rotors or motors connected to 4 propellers.

[0013] The four propellers are made of suitable materials (e.g., wood, conductive polymer, or carbon fiber with a conductive paint or varnish coating) and are protected against impact with structures and objects likely to be inspected by the drone. Each motor has thermal protection via NTC or RTD probes that activate a cut-off signal for each motor in the event of a failure.

[0014] In another example, the drone may comprise up to eight coaxial rotors or motors connected to the four propellers, i.e., one redundant motor per propeller. In this example, the drone is designed to operate with up to four motors disconnected.

[0015] In one example, the coaxial rotors are inrunner brushless motors powered by lithium batteries.

[0016] In one example, the polymeric material with conductive fillers comprises polymer or polymeric paint.

[0017] In one example, the pressure enclosure comprises pressure labyrinths and tight seals established in the pressure labyrinths in connection planes between the first cover and the central ring and between the second cover and the central ring to prevent leaks and achieve tightness.

[0018] In one example, the presuhped enclosure comprises one or more holes adapted to accommodate one or more cable glands (made of polyamide) configured to seal electrical cables from the presuhped enclosure. In one example, the first cover and the second cover comprise a domed shape. In one example, the one or more control and data acquisition sensors comprise cameras, and the second cover comprises transparent display panels.

[0019] In one example, the one or more control and data acquisition sensors comprise thermal, gas, pressure sensors, and / or an ultrasonic probe.

[0020] In one example, the center ring comprises carbon fiber.

[0021] In one example, the first cap comprises a pressurization valve and the second cap comprises a depressurization valve, where one or more control and data acquisition sensors comprise pressure sensors.

[0022] In one example, the drone control unit comprises a battery for autonomous operation of the control unit.

[0023] In one example, the third space houses an on-board computer configured to collect and manage information collected by the one or more data acquisition and control sensors.

[0024] Drone Safety

[0025] For the safety of the drone and its proper functioning in explosive gas atmospheres, the drone includes monitoring and redundancy means:

[0026] Regarding redundancy, the drone can include up to eight coaxial rotors and two lithium batteries, allowing for accident prevention in the event of a failure in any of the propulsion systems (motors, inverters, controller output, battery).

[0027] In terms of monitoring, the drone includes sensors to measure the temperatures of each of the motors.

[0028] The drone includes redundant sensors to monitor the internal pressure and temperature of the enclosure (e.g., ensuring that the internal temperature of the enclosure does not reach 200°C and obtaining correct pressure readings). The drone has an intrinsic safety circuit designed and built in such a way that it physically cannot produce short circuits or overcurrents. The intrinsic safety circuit is responsible for safely powering all of the drone's safety sensors, both internal and external. The intrinsic safety circuit is active at all times, since it has its own battery, allowing the drone to be pre-charged before turning it on. This way, the functioning sensors are already up and running, and pressurization does not affect their startup readings.

[0029] The drone includes cameras and LIDAR remote sensing capabilities to obtain information about the surroundings in point cloud format and recognize and construct the environment in real time. Based on this information, the drone is capable of autonomous navigation, taking into account its surroundings and avoiding collisions with both expected and unexpected objects that may be present at the inspection site.

[0030] The drone includes an ultrasonic probe for performing NDT tests such as measuring infrastructure thicknesses.

[0031] The drone is designed to be equipped with various sensors for specific data collection, such as gas detection cameras or even gas detectors.

[0032] Electrostatic spark forecast:

[0033] To prevent electrostatic sparks that can cause fire or explosions in explosive atmospheres, the parts that make up the casing are made of polymer with conductive charges in a first embodiment, or with a paint finish with conductive charges in a second embodiment.

[0034] Temperature limitation:

[0035] Monitoring the temperature both inside the drone and on its external components allows us to verify that the drone is operating normally, and also alerts us if the temperature rises unexpectedly so the drone can leave the explosive zone as quickly as possible. Temperatures of 200°C should never be reached, but they are monitored.

[0036] Detecting ambient temperature and avoiding exposing the drone to temperatures of around 200 degrees Celsius or higher is a requirement for the drone to operate safely in the presence of, for example, more than 90% of tabulated substances. Flammable gases are classified in tables by gas group and ignition temperature. By ensuring these requirements are met, safe flight can be ensured in the presence of up to 90% of tabulated, registered, recognized, etc. substances, which would allow the drone to fly in the vast majority of refineries (always gas, not dust).

[0037] The drone includes two temperature sensors that will send an alarm signal if temperatures reach or exceed 200 degrees Celsius. Depending on the situation, the mission can be aborted or the power supply to the faulty element can be cut off. If, for example, one engine becomes too hot compared to the rest, we can choose to shut it down in flight as an emergency measure. Thanks to the redundancy in the propulsion system, we can guarantee the safety and integrity of the equipment and facilities after such a power cut.

[0038] Drone Envelope

[0039] The structure of the drone according to the present invention comprises a pressurized enclosure that allows the avionics (i.e., the drone's control part) to be separated from the power electronics and the sensor array, thus minimizing the interference generated by the power electronics and the sensor array in the avionics. Furthermore, the proposed enclosure structure separates the power part (not subject to replacement) from the sensor array, which may require repair or exchange. Thus, the enclosure according to the present invention facilitates data extraction and maintenance operations.

[0040] At a mechanical level, it is interesting to house the power electronics in the central ring of the pressurized casing (the central ring comprises greater structural rigidity as it is made of carbon fiber) and to use two 'lids' to cover the rest of the internal elements as a capsule in a preferred embodiment.

[0041] The pressurized enclosure may be the optimal way to contemplate access to the exterior (drone cabling) from the pressurized enclosure, minimizing weak points in the chassis of the pressurized enclosure and internal pressure peaks (at specific times such as contact with structures, takeoffs and landings).

[0042] Retaining temperatures close to 200°C is a requirement that will allow safe operation in the presence of more than 90% of tabulated substances.

[0043] However, two temperature sensors will send an alarm signal if certain temperature values ​​close to or greater than 200° are reached, and the mission can be aborted or power to the faulty element cut off, depending on the case.

[0044] To complement the description being made and in order to help better understand the characteristics of the drone according to the present invention, some schematic figures are attached as an integral part of said description, where, for illustrative and non-limiting purposes, the following has been represented:

[0045] Figure 1 shows a preferred embodiment of the drone according to the present invention.

[0046] Figure 2 shows an exploded view of the envelope.

[0047] Figure 3 shows the central ring of the envelope.

[0048] Detailed embodiment of the invention

[0049] Figure 1 shows the operational safety drone (100) for outdoor industrial inspection, designed to operate in areas susceptible to occasional formation of explosive atmospheres. Due to the potential presence of flammable atmospheres in these areas, the drone (100) comprises features that prevent the exposure of risk elements to the potential mixture of explosive substances.

[0050] In the preferred embodiment, the drone (100) for explosive gas atmospheres comprises propulsion means (110) comprising propellers (110a) connected to eight coaxial rotors (110b).

[0051] The drone (100) is characterized by comprising coaxial rotors (110b) built with common systems of vertical propulsion aircraft and isolated from contact with flammable gases. The elements that must inevitably be exposed to these gases have been custom-developed to meet the operational needs required in explosive environments.

[0052] In this preferred embodiment, the drone (100) is propelled by eight brushless motors custom-made for the dimensions and operational safety characteristics of the drone (100). Each of the motors employed in the drone (100) is individually certified under an extensive series of material and dimensional requirements.

[0053] The coaxial rotors (110b) incorporated in the drone (100) are of the inrunner type, where the only external moving part is the motor shaft itself. Built under the defined premises, it is a motor that is protected against dust deposits and water projections coming from any direction.

[0054] The coaxial rotors (110b) have been designed to be powered by LiPo lithium batteries (170) and lift up to several kilos independently, so that in case of emergency up to four motors can be disconnected and the remaining ones are sufficient to return the drone (100) to the ground in safe conditions.

[0055] Structurally, the coaxial rotor cover (110b) is made of aluminum with a material composition sheet that excludes concentrations of magnesium and titanium.

[0056] The drone (100) comprises a pressurized casing (120) connected to the propulsion means (110) and comprising polymeric material with conductive charges. The pressurized casing (120) comprises a first cover (130), a central ring (140) and a second cover (150).

[0057] Figure 1 shows the pressurized enclosure (120), which is composed of a central ring (140) and the first cover (130) and the second cover (150) in the form of domes. Both the pressurized enclosure (120) and the chassis and arms of the drone (100) are designed and manufactured in a polymer with conductive charges from a constructive safety point of view, preventing the appearance of sparks due to electrostatics and in the event of a collision or accident of the vehicle.

[0058] Thus, the three pieces are made of polymer with a concentration of conductive charges that eliminate the electrostatic properties of plastics, thus mitigating one of the main causes of ignition of flammable gases.

[0059] Figure 2 shows the enclosure (120) of the drone (100) according to the present invention. The pressurized enclosure (120) comprises the first cover (130), the central ring (140) and the second cover (150).

[0060] Figure 2 shows a first (A) space defined between the first cover (130) and the central ring (140). The first space (A) houses the drone control unit for controlling at least the propulsion means.

[0061] The control unit comprises the electronic components and sensors for both controlling the drone (100) and collecting and analyzing data in real time.

[0062] The control unit is protected by the pressurized enclosure (120) that isolates these components from hostile external elements and conditions such as temperature, humidity, corrosive environments, harmful or flammable gases, etc.

[0063] In particular, the control unit comprises a safety system against a possible loss of pressure by activating early signals, to remove the drone (100) from the classified area before the pressure reaches levels that compromise the safety of the environment.

[0064] Figure 2 shows a second space (B) defined in the central ring (140) which houses the power electronics for supplying the propulsion means. Figure 2 shows a third space (C) defined between the second cover (150) and the central ring (140) which houses one or more control and data acquisition sensors controlled by the control unit.

[0065] In the third space (C) is the visual inspection sensors that are appropriate in each case: RGB, thermal, or gas images, as well as a small on-board computer responsible for collecting and managing the information collected.

[0066] As part of the control and data acquisition sensors, the drone (100) comprises cameras with sensors of different types and frontal and zenithal orientations, in addition to landing gear-like geometry.

[0067] As part of the control and data acquisition sensors, the drone (100) comprises an ultrasonic probe (160) configured to perform NDT inspections such as thickness measurements or detection of defects in metal structures.

[0068] The drone (100) is powered by two “packs” of lithium batteries (170) integrated into safety covers and external to the drone (100) that allow the rapid exchange of lithium batteries (170) without conditioning the drone (100) with long waiting periods during charging.

[0069] The lithium batteries (170) of the drone (100) are composed of several high-discharge rate lithium cells in series. The drone (100) mounts two independent lithium batteries (170) to power different propulsion circuits separately, guaranteeing redundant power supply.

[0070] Figure 3 shows the central ring (140) comprising an internal carbon fiber structure. This structure in turn has reinforcements to provide greater rigidity and dimensional stability to the upper and lower covers or domes.

[0071] To preserve the pressure inside the pressurized casing (120), the central ring (140) is provided with pressure labyrinths (140a) for O-rings. Pressure leaks are prevented by evenly distributing the pressure over the O-rings located in the pressure labyrinths (140a).

[0072] The absolute pressure inside the pressurized enclosure (120) is higher than atmospheric pressure, thus preventing air from entering the enclosure. The gas used for pressurization is nitrogen. Due to its lower density than air, the pressurized enclosure (120) has a loading valve in the upper cover (130) and a discharge valve in the lower cover (150).

[0073] The pressure inside the pressurized enclosure (120) is monitored for safety and redundancy by two independent high-precision pressure sensors. The sensors are read by the drone's on-board computer (100) via a safety circuit. The computer updates the pressure sensor readings with high frequency and notifies instantly in the event of an anomaly in any of the readings. If for any reason the pressure decreases inside the drone (100), the computer will issue alarm signals to the drone's operators (100) to abort the mission and leave the risk zone as soon as possible.

[0074] The pressurized enclosure (120) has six exit points for the wiring, managed through polyamide cable glands.

[0075] Figure 3 shows the central ring (140) without the O-rings, as well as four polyamide cable glands (140c).

[0076] An O-ring is a ring-shaped seal made of elastic material that is used to prevent leaks between two surfaces and achieve tightness.

[0077] Polyamide cable glands (140c) function in the same way as O-rings, but are used to seal electrical pipes or cables. In this case, the cables are supplied from inside the pressurized enclosure (120).

Claims

CLAIMS 1. Drone (100) for explosive gas atmospheres, comprising: propulsion means (110) comprising propellers (110a) connected to coaxial rotors (110b); pressurized casing (120) connected to the propulsion means (110) and comprising polymeric material with conductive charges, where the pressurized casing (120) comprises a first cover (130), a central ring (140) and a second cover (150), where a first (A) space defined between the first cover (130) and the central ring (140) houses the control unit of the drone (100) for controlling at least the propulsion means, where a second space (B) defined in the central ring (140) houses the power electronics for supplying the propulsion means; and where a third space (C) defined between the second cover (150) and the central ring (140) houses one or more control and data acquisition sensors.

2. Drone (100) for explosive gas atmospheres according to claim 1, wherein the propulsion means (110) comprises four coaxial rotors (110b) connected to four propellers (110a), respectively.

3. Drone (100) for explosive gas atmospheres according to the preceding claim, wherein the propulsion means (110) further comprises four redundant coaxial rotors connected to the four propellers (110a), respectively.

4. Drone (100) for explosive gas atmospheres according to claim 3, further comprising lithium batteries (170), and where the coaxial rotors and redundant coaxial rotors are inrunner type brushless motors powered by the lithium batteries (170).

5. Drone (100) for explosive gas atmospheres according to the preceding claims, wherein the polymeric material with conductive charges comprises polymer or polymeric paint.

6. Drone (100) for explosive gas atmospheres according to the previous claims, wherein the pressurized casing (120) comprises pressure labyrinths (120a) and tight seals established in the pressure labyrinths (140a) in connection planes between the first cover (130) and the central ring (140) and between the second cover (15) and the central ring (140) to prevent leaks and achieve tightness.

7. Drone (100) for explosive gas atmospheres according to the preceding claims, wherein the pressurized enclosure (120) comprises one or more holes (140b) adapted for the configuration of one or more polyamide cable glands (140c) configured to seal electrical cables coming from the pressurized enclosure (120).

8. Drone (100) for explosive gas atmospheres according to the preceding claims, wherein the first cover (130) and the second cover (150) comprise a domed shape.

9. Drone (100) for gas atmospheres according to the preceding claims, wherein the one or more control and data acquisition sensors comprise cameras and the second cover (150) comprises transparent viewers.

10. Drone (100) for gas atmospheres according to the preceding claims, wherein the one or more control and data acquisition sensors comprise thermal, gas, pressure sensors and / or an ultrasonic probe (160).

11. Drone (100) for gas atmospheres according to the preceding claims, wherein the one or more control and data acquisition sensors comprise redundant sensors for monitoring the pressure and internal temperature of the pressurized envelope (120).

12. Drone (100) for gas atmospheres according to the preceding claims, wherein the central ring (140) comprises carbon fiber.

13. Drone (100) for gas atmospheres according to the preceding claims, wherein the first cover (130) comprises a pressurization valve and the second cover (150) comprises a depressurization valve, where one or more control and data acquisition sensors comprise pressure sensors.

14. Drone (100) for gas atmospheres according to the preceding claims, wherein the control unit comprises its own battery for the autonomous operation of the control unit.

15. Drone (100) for gas atmospheres according to the preceding claims, wherein the third space (C) houses an on-board computer configured to collect and manage the information collected by the one or more control and data acquisition sensors.

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