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The present invention is related to the field of agricultural machine equipment. In particular, the present invention relates to grain dryers. More particularly, the present invention relates to a method and device for flowing an air stream through a grain flow, passing the air stream through a filter after passing through the grain flow so as to form a filtered air stream, and recycling a portion of the filtered air stream to clean the filter.
A grain dryer is used after grains are harvested. When the grains are harvested from the base of the plant, the grains have not had enough time to dry sufficiently. The presence of residual moisture inside the grains can be problematic for storing the grains. The moisture promotes fermentation and oxidation. Therefore, the use of a grain dryer, after the harvest, is essential in order to be able to store the grain under optimal conditions and to avoid any degradation of the grain.
Traditionally, a grain dryer for this type of application is comprised of at least one column, in which the grains can flow, namely by gravity. The grains are deposited in bulk at the level of the upper portion of the column; the grains fall through the column; and then, the grains are collected at the lower portion as dried grains.
Along the path inside the drying column, the grains contact the air inside the drying column. The air can have a controlled temperature, usually higher than the temperature of the grain. Traditionally, the air in the drying column can also be circulated so as to maintain a consistent temperature and remove particles, after passing through and drying the grains.
The recycling of the air in the traditional grain dryers is generally allowed by installing at least one filter, for example “bag filters”, often used in industrial environments. More particularly, the bag filters, which can be arranged either horizontally or vertically, permit a separation of the dust transported by an air stream and collected in a conduit.
Patents RU 2191061, JP 2000001224 and JP 11124232 describe the use of bag filters in order to trap the dust from the air stream when recycling the air flowing in a grain dryer.
The bag filters have the advantage of permitting an efficient dust separation; however, these filters the grain dryers must be cleaned, usually by being submitted to dust-removal operations.
A grain dryer having a bag filter must be shut down on average once every week in order to clean the filters that have become clogged by dust. This tedious and labor-intensive operation is necessary. A clogged bag filter can significantly reduce the performance and efficiency of the grain dryer. A clogged bag filter can lead to an increase in energy consumption.
The prior art patent, JP 2000 001224, provides a device into which grains or powders are poured, through a conduit, from a container. At the level of the conduit, an envelope is positioned, which is provided with an air-replacement orifice. At the level of this orifice, a filter is positioned. The outer portion of the filter is covered with a cap connected to a dust collector. A clearance is provided between the cap and the filter so as to permit an inlet of air from outside the device. However, this device does not allow an active drying of the grains or powders by another air flow circulating through the conduit. Therefore, there is no recirculation and recycling of the air flow that air flow through the conduit. Additionally, the same disadvantages of the conventional bag filters are also found in this device.
Other types of filters are described in the state of the art, for example in U.S. Pat. No. 4,563,200 and U.S. Pat. No. 4,690,700. However, these filters are in no way suitable for grain dryers.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The device for drying grain includes a housing having an inlet port and an outlet port, a first passageway having a first entry end and a first exit end, a first heating means mounted without the first passageway, a second passageway having a second entry end and a second exit end, and a grain flow housing. There is a filter means across the grain flow housing from the first exit end and the second exit end, a recovery column in fluid connection with the grain flow housing through the filter means, an air supplying means in fluid connection with the recovery column and the inlet port, and a recycle column in fluid connection with the air supplying means opposite the recovery column. Additionally, there is a filter cleaning means positioned within the recovery column, and a conveying means within the recovery column. The filter cleaning means includes a mobile blower, a blower intake, and a blower outlet. The conveying means raises and lowers the mobile blower along the filter means.
Embodiments of the present invention include the filtering means as a filter panel extending over at least part of the grain flow housing. There can also be a plurality of filter panels with each panel extending over at least part of the grain flow housing. The filter panel can be planar or comprised of two facets, each facet being contained in a different plane. The air supplying means can be a fan in fluid connection with the inlet port and the outlet port, drawing air by negative pressure through the inlet port and venting through the outlet port by positive pressure. The conveying means can be a pulley system or a motor on a track along the filtering means or the recovery column. As the conveying means moves the mobile blower, the blower intake can be a flexible conduit or a suction cone or baffle to pull air from the recycle column. The blower intake is sealed from the recovery column through a divider between the recovery column and the recycle column.
Alternative embodiments include a third passageway with a second heating means and a fourth passageway with a third heating means. The third and fourth passageways connect to the recycle column so that the device can include a second pass of air flow through the grains in an upper part of the grain flow housing. Another variation of this embodiment includes an upper filter means so that the second pass of air flow can also be filtered before venting through the outlet port of the housing. There is an analogous upper recovery column and upper recycle column. Further embodiments include an upper filter cleaning means to remove particles from the upper filter means. There can be an upper conveying means for aligning the upper filter cleaning means to the upper filter means.
The present invention includes the method for drying grain with the device. Once assembled, an external air flow passes into the housing through the inlet port by the air supplying means with negative pressure. A grain flow is poured through the grain flow housing, and the external air flow passes through the grain flow in a direction perpendicular to a direction of the grain flow so as to form a first pass air flow. The first pass air flow dries the grain in the grain flow. Then, the first pass air flow with first air flow retaining particles is filtered through the filter means so as to form a first filtered air flow in the recovery column. The first air flow retaining particles are retained by the filter means. A first portion of the first filtered flow is directed to the recycle column, and a second portion of the first filtered flow is directed from the recycle column through the filter means toward the grain flow so as to remove the first air flow retaining particles from the filter means. The method includes a conveying means to align the filter cleaning means along the filter means. There is an isolated blow out against the filter means to remove particles from the filter means. The first portion is eventually vented from the recycle column through the outlet port.
Embodiments of the method include passing the external air flow through the first passageway to the grain flow and passing the external air flow through the second passageway to the grain flow. The first heating means can differentiate from a cooling area and a first drying area in the grain flow housing, so a variation of the method includes heating the external air flow through the second passageway.
Additional embodiments of the method include the different components added to the device. When there is a third passageway and a second heating means within the third passageway, the step of directing the first portion of the first filtered flow can include additional steps before venting through the outlet port. There are similar variations when there is a fourth passageway, and a third heating means within the fourth passageway. The first portion can be treated and directed for second and third drying areas in the grain flow housing. The method can include a second pass air flow for drying more grain at the top of the grain flow housing.
Embodiments of the method also include filtering the second pass air flow with an upper filter means and cleaning the upper filter means. There can be the step of aligning the upper filter cleaning means along the upper filter means for removing particles from the upper filter means.
The device and method for drying grain of the present invention recycles air flow, after that air flow has been used as a first pass through the grain flow to dry grain. The recycling happens on two levels: some recycled air flow is used to clean the filter, and some recycled air flow is used for a second pass through the grain flow. There is no re-entry into the device by external air for the second pass. Additionally, the filter is cleaned to maintain efficiency of the filter without any down time. The filter can be cleaned without stopping operation.
The device 10 also comprises a first passageway 20 having a first entry end 22, a first exit end 24, and a first heating means 26 mounted within the first passageway, and a second passageway 30 having a second entry 32 end, and a second exit end 34. The inlet port 12 is in fluid connection with both the first entry end 22 and the second entry end 32.
Across the grain flow housing 40 from the first exit end 24 and the second exit end 34, the device 10 includes a filter means 50. The filtering means 50 is comprised of a filter panel 53 as in
Embodiments of the present invention also include a filter cleaning means 60, 60′ positioned within the recovery column 52.
There are also different embodiments of the mobile blower 62, 62′.
Another embodiment of
In the embodiment for the second pass through the grain flow, the device 10 can further comprise an upper filter means 100 across the grain flow housing 40 from the third exit end 84 and fourth exit end 94, if there is a fourth passageway 90, an upper recovery column 102 in fluid connection with the grain flow housing 40 through the upper filter means 100, and an upper recycle column 106 in fluid connection with the upper recovery column 102 at one end of the upper recovery column 102. Similar to the filter means 50, the upper filtering means 100 can be comprised of an upper filter panel 103 or a plurality of filter panels 53 as in
With this embodiment with the upper filtering means 100, the device 10 can further includes an upper filter cleaning means 110 positioned within the upper recovery column 102 and being comprised of an upper mobile blower 112, an upper blower intake 114, and an upper blower outlet 116. Again analogous to the filter cleaning means 60, the upper mobile blower 112 is in fluid connection with the upper recycle column 106 and the upper blower outlet 116. The upper blower intake 112 is sealed from the upper recovery column 102 through an upper divider 108 between the upper recovery column 102 and the upper recycle column 106.
Embodiments of the present invention include the method of drying grain.
A grain flow is poured through the grain flow housing 40 from the top to the bottom by gravity. The grain of the grain flow falls through the grain flow housing 40, and the air in the grain flow housing 40 dries the grain.
In the embodiments of the present invention, the method further comprises passing the external air flow through the grain flow in a direction perpendicular to a direction of the grain flow so as to form a first pass air flow. The first pass air flow dries the grain flow.
The method further comprises the steps of filtering the first pass air flow with first air flow retaining particles through the filter means 50 so as to form a first filtered air flow in the recovery column 52. The first air flow retaining particles are retained by the filter means 50. The filter means 50 can be clogged and blocked by these particles, which affects efficiency of the method in terms of negative pressure to draw air into the device 10 and drying the grain.
Embodiments of the present invention include the two levels of recycling. The method includes directing a first portion of the first filtered flow to the recycle column 56 and directing a second portion of the first filtered flow from the recycle column 56 through the filter means 50 toward the grain flow so as to remove the first air flow retaining particles from the filter means 50. The first portion from the recycle column 56 is vented through the outlet port 14. The second portion from the recycle column 56 is re-used to clean the filter means 50.
In one embodiment, the step of directing the second portion of the first filtered flow comprises the steps of: collecting the second portion of the first filtered flow from the recycle column 56 with the blower intake 64 by negative pressure of the mobile blower 62, positioning the mobile blower 62 with the conveying means 70, and blowing the second portion through the section 51 of the filter means 50 aligned with the blower outlet 66 in a direction opposite to a direction of the first pass air flow through the filter means 50. The mobile blower 62 is within the recovery column 52 and aligned with a section 51 of the filter means 50. Only a section 51 of the filter means 50 is cleaned at one time, so there is no complete reversal of air flow at the filter means 50. The air supplying means 54 is more powerful than the mobile blower 62, but the mobile blower 62 is more restricted to an air flow only at the section 51, not the entire filter means 50. The conveyor means 70 actuates the mobile blower 62 along the filter means so that eventually the entire filter means 50 is cleaned. The device 10 does not require shut down in order to clean the filter means 50, and the device 10 can run more efficiently while being regularly and simultaneously cleaned.
Other embodiments include the method comprising the step of filtering the second pass air flow with second air flow retaining particles through the upper filter means 100 so as to form a second filtered air flow in the upper recovery column 102. The second air flow retaining particles are retained by the upper filter means 100. The device 10 must further comprise the upper filter means 100 across the grain flow housing 40 from the third exit end 86, the upper recovery column 102 in fluid connection with the grain flow housing 40 through the upper filter means 100, and the upper recycle column 108 in fluid connection with the upper recovery column 102 at one end of the upper recovery column 102. The second pass air flow is also filtered so that the particles are removed again for the second filtered air flow.
Consequently, another embodiment includes cleaning the upper filter means 100, when the device 10 further includes the upper filter cleaning means 120 positioned within the upper recovery column 102 and being comprised of an upper mobile blower 112, an upper blower intake 114, and an upper blower outlet 116. Analogous to the mobile blower 82, the upper mobile blower 112 is in fluid connection with the upper recycle column 106 and the upper blower outlet 116. Similar to the steps of cleaning the filter means 50, the steps of cleaning the upper filter means 110 include directing a first upper portion of the second filtered air flow to the upper recycle column 106, venting the first upper portion from the upper recycle column 106 through the outlet port 14, and directing a second upper portion of the second filtered air flow from the upper recycle column 106 through the upper filter means 110 toward the grain flow so as to remove the second air flow retaining particles from the upper filter means 100.
In the embodiment of
In embodiments of the device 10 and method of the present invention, all of the air used in the lower portion of the housing 16 can be recycled so as to be re-used in the upper part of this same housing 16. Unlike traditional methods and devices, which rely on external air to mix with recycled air, the present invention does not rely on outside air. Generally, air from outside necessarily has a lower temperature than any internal recycled air that has already circulated through the grain flow housing 40. Therefore, in order to reach adequate temperature for drying grain, the external air requires a higher energy consumption than recycled air. Therefore, the method and the device according to the invention permit an improvement of the performance of drying of the grains.
In addition, part of the air recycled in the upper portion of the housing 40 in the second and third drying areas 46, 48, can be re-used in the lower portion of the housing 16 by the filter cleaning means 60. The device 10 fully re-uses the first filtered flow from the filter means 50. Furthermore, the embodiment of the filter panels 53 as planar simplifies the installation of device 10. Complicated, expensive and bulky suction devices requiring the installation of a piping, a motor and control cabinets is avoided. Instead, the filter cleaning means 60 of the present invention controls elimination particles and dust from the filter means 50 (and upper filter means 100), which are blown back towards the grain flow housing 40 for proper disposal or collection. The filter means 50 can be cleaned without interrupting the grain flow in the grain flow housing 40 and shut down of the device 10. The independence and separation of the mobile blower 62 continuously removes particles with air from the recycle column.
The invention is not limited to the examples shown and described above, which may have variants and modifications without departing from the scope of the invention.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made without departing from the true spirit of the invention.
The present application claims continuation-in-part priority under 35 U.S.C. § 120 from U.S. Ser. No. 14/207,271, filed on 12 Mar. 2014, and entitled “METHOD FOR FILTERING AN AIR FLOW IN A GRAIN DRYER”. See also Application Data Sheet.
Number | Date | Country | |
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Parent | 14207271 | Mar 2014 | US |
Child | 15940608 | US |