1. A method of transmitting a digital signal, the method comprising:
splitting the digital signal at baseband into a plurality of signals according to available frequency bands;
performing inverse fast Fourier transformation (IFFT) on each of the plurality of signals to generate subcarriers; and
transmitting the subcarriers through the available frequency bands.
2. The method of transmitting a digital signal of claim 1, the method further comprising searching for the available frequency bands using cognitive radio technology.
3. The method of transmitting a digital signal of claim 1,
wherein the plurality of signals comprises a plurality of subcarrier groups, and each of the subcarrier groups comprises at least one subcarrier,
wherein the IFFT is performed on each of the subcarrier groups, and
wherein the transmitting comprises:
low-pass-filtering each of the subcarrier groups;
modulating each of the low-pass-filtered subcarrier groups independently using different radio frequency (RF) signal; and
transmitting the modulated subcarrier groups.
4. The method of transmitting a digital signal of claim 3, wherein the modulating each of the low-pass-filtered subcarrier groups comprises frequency up-converting each of the low-pass-filtered subcarrier groups using the different RF signals.
5. The method of transmitting a digital signal of claim 3, wherein the low-pass-filtering is performed according to a bandwidth of each of the subcarrier groups.
6. The method of transmitting a digital signal of claim 3, wherein the different RF signals have different frequencies from each other, and are generated by at least one of a frequency divider and a frequency multiplier using a signal output from a phase-locked loop (PLL) circuit.
7. A computer readable recording medium having recorded thereon a computer program for executing a method of transmitting a digital signal, the method comprising:
splitting the digital signal at baseband into a plurality of signals according to available frequency bands;
performing inverse fast Fourier transformation (IFFT) on each of the plurality of signals to generate subcarriers; and
transmitting the subcarriers through the available frequency bands.
8. An apparatus for transmitting a digital signal, the apparatus comprising:
a splitter which splits the digital signal at baseband into a plurality of signals according to available frequency bands;
a plurality of inverse fast Fourier transformation (IFFT) units which performs IFFT on each of the plurality of signals to generate subcarriers; and
a transmitter which transmits the subcarriers through the available frequency bands.
9. The apparatus for transmitting a digital signal of claim 8, the apparatus further comprising a cognitive unit which searches for the available frequency bands using cognitive radio technology.
10. The apparatus for transmitting a digital signal of claim 8,
wherein the plurality of signals split according to the available frequency bands comprise a plurality of subcarrier groups, and each of the subcarrier groups comprises at least one subcarrier,
wherein the IFFT is performed on each of the subcarrier groups, and wherein the transmitter comprises:
a plurality of low-pass filters which low-pass-filters each of the subcarrier groups;
a plurality of mixers which modulates each of the low-pass-filtered subcarrier groups independently using different radio frequency (RF) signals; and
a plurality of RF transmitters which transmits the modulated subcarrier groups.
11. The apparatus for transmitting a digital signal of claim 10, wherein the mixers are configured to frequency up-convert each of the low-pass-filtered subcarrier groups using the different RF signals.
12. The apparatus for transmitting a digital signal of claim 10, wherein the low-pass filters low-pass-filter each of the subcarrier groups according to a bandwidth of each of the subcarrier groups.
13. The apparatus for transmitting a digital signal of claim 10, the apparatus further comprising:
a phase-locked loop (PLL) circuit which generates an RF signal; and
at least one of a frequency divider and a frequency multiplier which generates the different RF signals which have different frequencies from each other using the RF signal output from the PLL circuit,
wherein the mixers modulate the subcarrier groups using the different RF signals which have different frequencies from each other.
14. A method of receiving a digital signal, the method comprising:
receiving subcarrier groups modulated using radio frequency (RF) signals which have different frequencies from each other;
demodulating each of the subcarrier groups so that all subcarriers of each of the subcarrier groups are arranged adjacent to each other at baseband;
performing fast Fourier transformation (FFT) on each of the demodulated subcarrier groups independently; and
combining the subcarrier groups on which the FFT is performed.
15. The method of receiving a digital signal of claim 14, wherein the demodulating comprises:
frequency down-converting each of the subcarrier groups independently using the RF signals which have different frequencies from each other; and
low-pass-filtering each of the frequency down-converted subcarrier groups according to a bandwidth of each of the subcarrier groups.
16. The method of receiving a digital signal of claim 15, wherein the RF signals which have different frequencies from each other are generated by at least one of a frequency divider and a frequency multiplier using a signal output from a phase-locked loop (PLL) circuit.
17. A computer readable recording medium having recorded thereon a computer program for executing a method of receiving a digital signal, the method comprising:
receiving subcarrier groups modulated using radio frequency (RF) signals which have different frequencies from each other;
demodulating each of the subcarrier groups so that all subcarriers of each of the subcarrier groups are arranged adjacent to each other at baseband;
performing fast Fourier transformation (FFT) on each of the demodulated subcarrier groups independently; and
combining the subcarrier groups on which the FFT is performed.
18. An apparatus for receiving a digital signal, the apparatus comprising:
a radio frequency (RF) receiver which receives subcarrier groups modulated using RF signals which have different frequencies from each other;
a demodulator which demodulates each of the subcarrier groups so that all subcarriers of each of the subcarrier groups are arranged adjacent to each other at baseband;
a plurality of fast Fourier transformation (FFT) units which performs FFT on each of the demodulated subcarrier groups independently; and
a combiner which combines the subcarrier groups on which the FFT is performed.
19. The apparatus for receiving a digital signal of claim 18, wherein the demodulator comprises:
a plurality of mixers which frequency down-converts each of the subcarrier groups independently using the RF signals which have different frequencies from each other; and
a plurality of low-pass filters which low-pass-filters each of the frequency down-converted subcarrier groups according to a bandwidth of each of the subcarrier groups.
20. The apparatus for receiving a digital signal of claim 19, the apparatus further comprising:
a phase-locked loop (PLL) circuit which generates an RF signal; and
at least one of a frequency divider and a frequency multiplier which generates the RF signals which have different frequencies from each other using the RF signal output from the PLL circuit,
wherein the mixers modulates the subcarrier groups using the RF signals which have different frequencies from each other.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of transferring proppant for fracking to reduce risk of production and release of silica dust at a well site, the method comprising:
positioning a plurality of containers each having proppant for fracking contained therein onto a conveyor at a well site, the conveyor having a plurality of conveyor hoppers and each of the plurality of conveyor hoppers overlaying a conveyor belt, each respective container having a sealed top to reduce the risk of release of silica dust associated with proppant into the air;
downwardly discharging proppant from each respective container of the plurality of containers, each respective container further having inclined lower inner portions and one or more outlets positioned at a bottom of each respective container, such that as proppant flows by gravity feed along the inclined lower inner portions to and through the one or more outlets, risk of production and release of silica dust into the air is thereby reduced, and the respective container is substantially emptied of proppant;
funneling proppant from the one or more outlets of each of the plurality of containers through the plurality of conveyor hoppers, each respective conveyor hopper having a plurality of inclined side portions and one or more controllable openings positioned adjacent and overlying the conveyor belt, such that as proppant flows by gravity feed along the plurality of inclined side portions of each of the plurality of conveyor hoppers through the one or more controllable openings to the conveyor belt, risk of production and release of silica dust into the air through the one or more controllable openings is thereby reduced;
receiving proppant onto the conveyor belt, the conveyor belt having a plurality of partitions associated therewith, such that the plurality of partitions are positioned to reduce the risk of production and release of silica dust into the air as the proppant contacts and is carried by the conveyor belt;
conveying proppant on the conveyor to a chute, the conveyor belt having a first end portion and a second end portion, the second end portion of the conveyor belt including a shrouded portion that has a shroud substantially enclosing the conveyor belt and positioned to substantially reduce the risk of release of silica dust associated with proppant into the air as the proppant is conveyed through the shrouded portion; and
depositing the proppant from the second end portion of the conveyor into the chute.
2. The method of claim 1, further comprising:
after proppant has been discharged from a respective container of the plurality of containers, removing the respective container from the conveyor for replacement with another respective container filled with proppant, such that the conveyor belt continuously conveys proppant at the well site from the plurality of containers to the chute.
3. The method of claim 1, further comprising:
controlling the rate of proppant as it flows through the one or more outlets of each respective container using a flow gate positioned at the one or more outlets to reduce the risk of production and release of silica dust into the air through the one or more outlets, the flow gate optionally controlled by hydraulics or electronics to enhance opening and closing of the flow gate, wherein the plurality of conveyor hoppers are positioned side-by-side and are substantially aligned with the plurality of containers.
4. The method of claim 1, wherein the inclined lower inner portions of each respective container are inclined inwardly from inner walls of the respective container toward a bottom of the container at an angle of about 31 degrees to about 37 degrees relative to a horizontal plane of the bottom of each respective container when each respective container is level.
5. The method of claim 1, further comprising:
controlling the rate of proppant as it flows from the one or more controllable openings of each respective conveyor hopper to reduce the risk of production and release of silica, dust into the air through the one or more controllable openings, the one or more controllable openings having a hopper gate and a hopper gate actuator, the hopper gate actuator optionally controlled by hydraulics or electronics to enhance opening and closing of the one or more controllable openings; and
positioning the plurality of inclined side portions, wherein the plurality of inclined side portions further comprise a pair of short side portions having a funnel angle or slope of approximately 35 to 40 degrees relative to a horizontal plane, and a pair of long side portions having a funnel angle or slope of approximately 28 to 33 degrees relative to a horizontal plane, to maximize the capacity of the conveyor hopper and the flow of proppant from the conveyor hopper.
6. The method of claim 1, wherein the shrouded portion is positioned between a last respective container on the conveyor and the chute at an angle of approximately 30 to 60 degrees from a horizontal plane when the conveyor is level.
7. (canceled)
8. The method of claim 1, wherein the plurality of partitions comprises a plurality of fingers, each respective finger extending, upwardly from the conveyor belt and spaced apart from another respective finger, and a plurality of side walls, each respective side wall extending upwardly from and positioned near an outside edge of the conveyor belt, to reduce the production and release of silica dust as proppant received and conveyed on the conveyor belt.
9. The method of claim 8, wherein the plurality of containers are positioned adjacent each other on the conveyor, and wherein each of a plurality of partitions of the conveyor belt connect to and extend upwardly from a top surface of the conveyor belt toward the conveyor hopper when positioned to underlie the conveyor hopper, and each of the plurality of fingers is spaced-apart from another one of the plurality of lingers so that the top surface of the conveyor belt receives the proppant thereon and between the plurality of partitions.
10. A method for reducing risk of production and release of silica dust at a well site during, the transport of proppant for fracking, the method comprising:
utilizing a plurality of containers having proppant for fracking contained therein, each respective container having an outlet and a sealed top, the sealed top positioned to reduce risk of release of silica dust associated with proppant from the sealed top of each respective container;
positioning each respective container on a conveyor at the well site, the conveyor having a plurality of hoppers and each of the plurality of hoppers having an opening that is in fluid communication with a conveyor belt that underlies the conveyor to reduce risk of production and release of silica dust associated with proppant as the proppant flows from each respective container;
downwardly discharging the proppant from each respective container through each respective opening of each respective hopper onto the conveyor belt, the conveyor belt having a first end portion, a second end portion, and a plurality of partitions associated therewith, the plurality of partitions of the conveyor belt positioned to reduce risk of production and release of silica dust as the proppant contacts and is carried by the conveyor belt;
conveying the proppant to a blender hopper; and
depositing the proppant into the blender hopper by gravity feed.
11. The method of claim 10, wherein each of the plurality of containers has a plurality of inclined lower inner portions inclined at an angle of about 31 degrees to about 37 degrees relative to a horizontal plane of a bottom of each respective container when each respective container is level, such that proppant downwardly flows by gravity feed along the plurality of inclined lower inner portions to reduce risk of production and release of silica dust associated with proppant into the air at the outlet of each respective container until each respective container is substantially empty of proppant.
12. The method of claim 10, further comprising:
after proppant has been downwardly discharged from each respective container, removing each respective container from the conveyor at the well site with a forklift for replacement with a second respective container filled with proppant for fracking contained therein such that the conveyor belt is continuously conveying proppant to the chute.
13. The method of claim 10, further comprising:
controlling the rate of proppant flowing from each respective container using a flow gate positioned at the outlet of each respective container to reduce risk of production and release of silica dust associated with proppant into the air as proppant flows out of the outlet; and
optionally controlling the flow gate by hydraulics or electronics to enhance opening and closing of the flow gate to reduce risk of production and release of silica dust associated with proppant into the air as proppant flows out of the outlet.
14. The method of claim 10, further comprising:
controlling the rate of proppant downwardly flowing from each respective hopper using a hopper gate and a hopper gate actuator positioned at the controllable opening of each respective hopper, wherein the plurality of hoppers are positioned side-by-side and are substantially aligned with the plurality of containers; and
optionally controlling the hopper gate actuator by hydraulics or electronics to enhance opening and closing of the hopper gate to reduce risk of production and release of silica dust associated with proppant into the air as proppant flows out of the controllable opening.
15. The method of claim 10, further comprising positioning a shroud over a portion of the second end portion of the conveyor belt thereby to define a shrouded portion, the shroud substantially enclosing the shrouded portion to reduce the risk of release of silica dust associated with the proppant into the air.
16. The method of claim 10, wherein each of the plurality of containers is positioned side-by-side on the conveyor, and a top surface of the conveyor is substantially aligned with a plane of a respective top portion of each hopper of the plurality of hoppers.
17. The method of claim 10, wherein the plurality of containers are positioned adjacent each other on the conveyor, and wherein each of the plurality of partitions of the conveyor belt extend upwardly from a top surface of the conveyor belt toward the plurality of hoppers when positioned to underlie the plurality of hoppers and each of the plurality of fingers is spaced-apart from another one of the plurality of fingers so that the top surface of the conveyor belt receives the proppant thereon and between the plurality of partitions.
18. A system to convey proppant for fracking from a plurality of containers to a chute thereby to reduce risk of production and release of silica dust at a well site, the system comprising:
the plurality of containers each adapted to have proppant for fracking contained therein, each respective container having a sealed top to reduce risk of release of silica dust associated with proppant into the air when positioned therein, each respective container further having interior portions inclined toward an outlet at a bottom of each respective container to reduce risk of production and release of silica dust associated with proppant as the proppant flows from each respective container until each respective container is substantially empty;
a conveyor positioned at the well site and to receive each respective container of the plurality of containers, the conveyor having one or more conveyor hoppers that align closely with each respective outlet of the plurality of containers to reduce risk of production and release of silica dust into the air, each of the one or more respective conveyor hoppers having a lower portion including an opening, such that when proppant downwardly flows through each respective outlet of each respective container of the plurality of containers when positioned therein, the proppant passes to and through the opening of each of the one or more respective conveyor hoppers;
a conveyor belt positioned to underlie the one or more conveyor hoppers to receive proppant as the proppant passes to and through the opening of each of the one or more respective conveyor hoppers, the conveyor belt having a first end, a second end, and a plurality of partitions associated therewith, such that the plurality of partitions are positioned to reduce risk of production and release of silica dust as proppant contacts and is carried by the conveyor belt;
a shroud positioned to overlie a portion of the second end of the conveyor belt thereby to define a shrouded portion of the conveyor belt, the shroud substantially enclosing the shrouded portion as the conveyor belt conveys proppant when positioned thereon from the plurality of containers to reduce risk of release of silica dust associated with proppant into the air from the portion; and
the chute having an inlet positioned to receive the second end of the conveyor belt conveying proppant and one or more outlets positioned such that as proppant is deposited into the chute by gravity feed, proppant flows out of the one or more outlets to one or more blenders or other location at the well site.
19. The system of claim 18, wherein the interior walls inclined toward an outlet at the bottom of each respective container are inclined at an angle of about 31 degrees to about 37 degrees relative to a horizontal plane of a bottom of each respective container when each respective container is level.
20. The system of claim 18, wherein each respective conveyor hopper of the plurality of conveyor hoppers has a plurality of inclined side portions, and wherein the plurality of inclined side portions further comprise a pair of short side portions having a funnel angle or slope of approximately 35 to 40 degrees relative to a horizontal plane, and a pair of long side portions having a funnel angle or slope of approximately 28 to 33 degrees relative to a second horizontal plane, to maximize the capacity of the conveyor hopper and the flow of proppant from the conveyor hopper, and to reduce the risk of production and release of silica dust associated with proppant as it flows along the plurality of inclined side portions, and wherein the plurality of conveyor hoppers are positioned side-by-side and are substantially aligned with the plurality of containers.
21. The system of claim 18, further comprising a blender hopper cover positioned to reduce risk of production and release of silica dust as proppant flows between the one or more outlets of the chute and one or more blender hoppers of the one or more blenders at the well site.
22. The system of claim 18, wherein each of the plurality of containers has one or more slots positioned adjacent a bottom portion of the respective container, and the system further comprising a forklift positioned at the well site to load and unload each respective container onto and off of the conveyor by the one or more slots.
23. The system of claim 18, wherein the conveyor comprises a plurality of curtains positioned to reduce risk of production and release of silica dust as proppant flows from the plurality of conveyor hoppers to the conveyor belt.
24. The system of claim 18, wherein the plurality of partitions comprises a plurality of fingers, each respective finger connected to, and extending upwardly from the conveyor belt and spaced apart front another respective finger, and a plurality of side walls, each respective side wall connected to and extending upwardly from, and positioned at or near, an outside edge of the conveyor belt, to reduce the production and release of silica dust as proppant is received and conveyed on the conveyor belt.
25. The system of claim 18, further comprising:
a flow gate positioned at the outlet of each respective container to control the downward flow of proppant through the outlet to reduce the risk of production and release of silica dust associated with proppant into the air through the outlet, and wherein each of the plurality of partitions of the conveyor belt extend upwardly from a top surface of the conveyor belt toward a hopper of the one or more conveyor hoppers hopper when positioned to underlie the hopper of the one or more conveyor hoppers and each of the plurality of fingers is spaced-apart from another one of the plurality of fingers so that the top surface of the conveyor belt receives the proppant thereon and between the plurality of partitions when the proppant discharges from the hopper of the one or more conveyor hoppers.
26. A system to convey proppant for fracking from a plurality of containers to one or more blender hoppers thereby to reduce risk of production and release of silica dust at a well site, the system comprising:
the plurality of containers each adapted to have proppant for fracking contained therein, each respective container having a sealed top to reduce risk of release of silica dust associated with proppant into the air when positioned therein, each respective container further having interior portions inclined toward an outlet at a bottom of each respective container to reduce risk of production and release of silica dust associated with proppant as the proppant flows from each respective container until each respective container is substantially empty;
a conveyor positioned at the well site and to receive each respective container of the plurality of containers; the conveyor having one or more conveyor hoppers that align closely with each respective outlet of the plurality of containers to reduce risk of production and release of silica dust into the air, each of the one or more respective conveyor hoppers having a lower portion including an opening, such that when proppant downwardly flows through each respective outlet of each respective container of the plurality of containers when positioned therein, the proppant passes to and through the opening of each of the one or more respective conveyor hoppers;
a conveyor belt positioned to underlie the one or more conveyor hoppers to receive proppant as the proppant passes to and through the opening of each of the one or more respective conveyor hoppers, the conveyor belt having a first end, a second end, and a plurality of partitions associated therewith, such that the plurality of partitions are positioned to reduce risk of production and release of silica dust as proppant contacts and is carried by the conveyor belt;
the one or more blender hoppers having an inlet positioned to receive the second end of the conveyor belt conveying proppant such that proppant is deposited into the one or more blender hoppers by gravity feed.
27. The system of claim 26, wherein the interior portions inclined toward an outlet at the bottom of each respective container are inclined at an angle of about 31 degrees to about 37 degrees relative to a horizontal plane of the bottom of each respective container when each respective container is level.
28. The system of claim 26, wherein each respective conveyor hopper of the plurality of conveyor hoppers has a plurality of inclined side portions, and wherein the plurality of inclined side portions further comprise a pair of short side portions having a funnel angle or slope of approximately 35 to 40 degrees relative to a horizontal plane, and a pair of long side portions having a funnel angle or slope of approximately 28 to 33 degrees relative to a second horizontal plane, to maximize the capacity of the conveyor hopper and the flow of proppant from the conveyor hopper, and to reduce the risk of production and release of silica dust associated with proppant as it flows along the plurality of inclined side portions, and wherein the plurality of conveyor hoppers are positioned side-by-side and are substantially aligned with the plurality of containers.
29. The system of claim 26, further comprising a blender hopper cover positioned to reduce risk of production and release of silica dust as proppant flows between one or more outlets of a chute and the one or more blender hoppers of one or more blenders at the well site.
30. The system of claim 26, wherein each of the plurality of containers has one or more slots positioned adjacent a bottom portion of the respective container, and the system further comprising a forklift positioned at a well site to load and unload each respective container onto and off of the conveyor by the one or more slots.
31. The system of claim 8, wherein the plurality of containers are positioned in a side-by-side arrangement on the conveyor and a height of the plurality of side walls is substantially similar to a height of the plurality of fingers.