Patent Application
20190344230
The present invention relates to the preparation of gels, and specifically gels derived from hydration of particulate materials such as powders.
It is known in the art of gel production to form gels from a mixture of water and dry base powders. It is known in the art of firefighting specifically to employ gels with fire-retardant properties, and many such gels are known to the skilled person, as well as methods for forming such gels from dry base powders.
For example, U.S. Pat. No. 3,777,775 to Handleman discloses a system for creating a firefighting slurry/solution by introducing an air/powder mixture into a water stream, and using an eductor vacuum to achieve mixing.
In a further example, Canadian Patent No. 780,113 to Katzer et al. teaches introducing powder into an atmospheric air stream driven by Venturi forces, and then introducing a water stream to the air/powder stream, again employing a vacuum (eductor) to achieve the desired mixing.
However, it is believed that many prior art systems result in incomplete hydration of the base powder, or “clumping” of the powder when introduced to the water supply and mixed. In order to optimize the fire-retardant properties of the resultant gel, it will be clear to those skilled in the art that maximizing the number of hydrated powder particles is desirable as non-hydrated powder particles do not manifest the desirable fire-retardant properties. The prior art systems fail to achieve this goal. As well, eductor systems are known to be limited to low-pressure output, as pressures exceeding 12 to 13 psi may cause the eductor to stop working, since the delta pressure can generally only be between 0 and 15 psi. Further, in many prior art systems precision metering of powder is an issue because the conventional use of a Venturi is inadequate as a metering technique.
What is needed, therefore, is a system and method for producing a gel from a base powder, in which the hydration of powder particles is optimized when compared to prior art systems.
The present invention therefore seeks to provide a system and method in which the powder particles are metered, fluidized within an air stream to disperse the metered particles, and then injected into a water stream for hydration. However, the pressure of the air/powder stream is greater than the pressure of the water stream, to enhance hydration of individual powder particles rather than collapse and clumping.
According to a first broad aspect of the present invention, then, there is provided a system for producing a gel, the system comprising:
a mixing chamber;
a water subsystem comprising:
a powder fluidization subsystem comprising:
wherein the fluidized powder supply is introduced to the pressurized water stream in the mixing chamber to hydrate the powder in the fluidized powder supply therein to form the gel; and
wherein the second pressure is greater than the first pressure.
In some exemplary embodiments of the first aspect, the powder supply comprises a pressure vessel, and the system may further comprise a vacuum pressurization subsystem to supply the powder to the pressure vessel.
The mixing chamber preferably physically constrains the pressurized water supply and the fluidized powder supply for mixing thereof. In some preferred embodiments, the mixing chamber comprises a pipe section substantially parallel with a flow direction of the pressurized water stream upon exiting the water subsystem.
The water subsystem preferably comprises a water pump for pressurizing the pressurized water supply and supplying the pressurized water stream to the mixing chamber, and the flow and pressure of the pressurized water stream is preferably monitored respectively by a process water flow meter and a process water pressure transducer.
The pressurized air supply may be achieved by an air compressor, with the pressure of the fluidized powder supply monitored by an air/powder pressure transducer.
In some exemplary embodiments, the second pressure is measured by an air/powder pressure transducer and the first pressure is measured by a process water pressure transducer, to ensure that the second pressure is greater than the first pressure.
The metering valve may be powered by a variable speed drive.
The gel is preferably discharged from the mixing chamber into a tank for storage and transport, such as for subsequent use as a fire-retardant gel in a firefighting operation.
According to a second broad aspect of the present invention, there is provided a method for producing a gel, the method comprising the steps of:
In some exemplary embodiments of the second aspect, the method further comprises the step of providing a mixing chamber for receiving the pressurized water stream and the fluidized powder supply.
The method preferably further comprises monitoring the first pressure and the second pressure. Further, a flow volume of the pressurized water stream is preferably monitored, wherein the metering of the powder is conducted at a flow rate/volume based on the flow volume and a selected mixture concentration. The selected mixture concentration may be 100:1 ratio by weight of water to powder, although other concentrations may be appropriate in the view of the skilled person.
Some exemplary methods further comprise the step after step e. of ceasing introduction of the fluidized powder supply into the pressurized water stream if either the second pressure falls below the first pressure, or providing of the pressurized water stream or the pressurized air stream ceases.
In some exemplary embodiments the method further comprises discharging the gel for storage and transport.
A detailed description of an exemplary embodiment of the present invention is given in the following. It is to be understood, however, that the invention is not to be construed as being limited to this embodiment. The exemplary embodiment is directed to a particular application of the present invention, while it will be clear to those skilled in the art that the present invention has applicability beyond the exemplary embodiment set forth herein.
In the accompanying drawings, which illustrate an exemplary embodiment of the present invention:
An exemplary embodiment of the present invention will now be described with reference to the accompanying drawings.
Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. The following description of an example of the technology is not intended to be exhaustive or to limit the invention to the precise form of any exemplary embodiment. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.
Turning to
To fill the pressure vessel 12 with powder, a vacuum process may be employed. While a vacuum fill process is described below, it will be clear to those skilled in the art that other filling means may be used, such as, for non-limiting examples, a combined positive pressure and vacuum (push-pull) process, a solely positive pressure process, or a process of manually introducing powder into the vessel 12 via a sealable filling aperture (not shown in the accompanying drawings). As is illustrated in the process flow diagram of
Use of the system 10 for gel production employs air pressure. The valve 32 is opened, and once the vessel pressure transducer 68 indicates that the vessel 12 has reached a desirable pressure level the vessel discharge valve 34 can be opened. Preparation of the gel can then begin.
With reference to the piping and instrumentation diagram of
The variable speed drive for the metering valve 14 is then powered up, and powder flows from the vessel 12 through the valve 14 at a pre-determined flow rate/volume based on water volume from the process water flow meter 58 and the desired mix ratio, which is confirmed by a powder mass change measurement calculated using a weighing device 63 comprising load cells (shown in
The gel forms by the hydration of the powder, and the resultant gel is output at the gel outlet 26. The specific gravity of the gel may or may not be monitored and reported before discharge to a receptacle, at a gel viscosity meter 66. In this exemplary embodiment the gel is discharged into an aircraft payload tank for eventual air delivery to a fire such as a forest fire, but embodiments of the present invention could be employed in other settings.
Throughout loading, the process water flow meter 58, process water pressure transducer 60, powder mass flow meter 64 and air/powder pressure transducer 62 are continuously monitored. Alternatively, the process water flow meter 58 and the process water pressure transducer 60 can be monitored together with powder depletion measured as a function of vessel 12 powder mass change as determined from the weighing device 63 and the air/powder pressure transducer 62. If flow in either water flow or powder flow/depletion ceases, or if the water pressure becomes greater than the air pressure, the process is shut down. When sufficient gel has been produced and discharged, the metering valve 14 and water pump 18 are shut down, and the water and air/powder discharge valves 48 and 52 are closed.
As will be clear from the foregoing, embodiments of the present invention may provide a number of desirable advantages over the prior art. For example, fluidizing the powder in a high-pressure air stream can act to better disperse the powder particles in the water stream upon mixing of the streams, which may thus avoid or reduce clumping of the powder, thereby better optimizing the gel production. Other advantages will be clear to the skilled person, such as the ease with which a system like the above exemplary embodiment can be made portable for use with remote firefighting activity.
Unless the context clearly requires otherwise, throughout the description and the claims:
Words that indicate directions such as “vertical”, “transverse”, “horizontal”, “upward”, “downward”, “forward”, “backward”, “inward”, “outward”, “vertical”, “transverse”, “left”, “right”, “front”, “back”, “top”, “bottom”, “below”, “above”, “under”, and the like, used in this description and any accompanying claims (where present) depend on the specific orientation of the apparatus described and illustrated. The subject matter described herein may assume various alternative orientations. Accordingly, these directional terms are not strictly defined and should not be interpreted narrowly.
Where a component (e.g. a circuit, module, assembly, device, drill string component, drill rig system etc.) is referred to herein, unless otherwise indicated, reference to that component (including a reference to a “means”) should be interpreted as including as equivalents of that component any component which performs the function of the described component (i.e., that is functionally equivalent), including components which are not structurally equivalent to the disclosed structure which performs the function in the illustrated exemplary embodiments of the invention.
Specific examples of methods and apparatus have been described herein for purposes of illustration. These are only examples. The technology provided herein can be applied to contexts other than the exemplary contexts described above. Many alterations, modifications, additions, omissions and permutations are possible within the practice of this invention. This invention includes variations on described embodiments that would be apparent to the skilled person, including variations obtained by: replacing features, elements and/or acts with equivalent features, elements and/or acts; mixing and matching of features, elements and/or acts from different embodiments; combining features, elements and/or acts from embodiments as described herein with features, elements and/or acts of other technology; and/or omitting combining features, elements and/or acts from described embodiments.
The foregoing is considered as illustrative only of the principles of the invention. The scope of the claims should not be limited by the exemplary embodiments set forth in the foregoing, but should be given the broadest interpretation consistent with the specification as a whole.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2017/051325 | 11/8/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62420376 | Nov 2016 | US |
