Patent Grant
10317138
The present invention relates to baffle systems for conveyor-type dryers and methods of replacing baffle seal strips.
Single and multiple deck conveyor dryers for reducing the moisture content of sheet materials, including green (i.e. wet) wood veneer, wherein the material being dried is conveyed through a stationary drying chamber while heated gases are circulated through the drying chamber, are well-known in the art. Evaporation of moisture from the material being dried causes a build-up of steam within the dryer and creates a positive pressure differential within the dryer relative to the external atmosphere. Disposal of large amounts of gases containing volatile organic compounds (V.O.C.) which are evolved from the wood veneer during drying has been a major problem in the wood veneer drying art. Typically, gases are removed by an exhaust system and, in some systems, are exhausted directly to the atmosphere. By allowing gases to be exhausted directly to the atmosphere, pollutants have been allowed to escape and considerable quantities of heat energy are lost which is a considerable cost expense.
It is desirable to control the exhaust of gases from a wood veneer dryer to optimize the drying efficiency of the dryer and to provide a means for containing and treating the exhaust gases prior to discharge into the atmosphere. Such means include installing a V.O.C. separating device such as a catalytic or thermal oxidizer in the exhaust system. Such devices are well-known in the art.
If the drying process is not carefully controlled and optimized, untreated gases (i.e. gases containing V.O.C.) within a dryer will be discharged through not only the exhaust system, but through input and output ends of the dryer due to the positive pressure differential within the dryer. This presents real environmental concerns and health and safety hazards to workers. Prior art dryers have other disadvantages, including a loss of efficiency due to the entrance of air at ambient temperature into the dryer through input and output ends if a negative pressure differential is created within the dryer relative to the external atmosphere if gases are exhausted too quickly. Entrance of cooler ambient air reduces the temperature of the dryer, wasting a considerable amount of energy to reheat the dryer and resulting in pitch (i.e. condensed V.O.C. material) build-up within the dryer. This is an obvious fire hazard. Attempts have been made to control the inflow and outflow of gases through the input and output ends of wood veneer dryers using stop-offs or baffles. An example of one such attempt to improve wood veneer dryer efficiency and safety is disclosed in U.S. Pat. No. 4,439,930. However, with use, the stop-offs or baffles wear and the inflow and outflow of gases from the input and output ends of the dryer increases. To replace or adjust the worn stop-offs or baffles, the operator is required to stop operation of the wood veneer dryer to gain access to the stop-offs or baffles inside the dryer once the dryer has cooled. To access the worn stop-offs or baffles, one or more of dryer rollers, jet tubes, and conveyor chains of the dryer must be removed. Typically, about three operators are required to then remove the heavy stop-off or baffle. The process to replace or adjust worn stop-offs or baffles typically takes approximately 16 to 20 hours. The time the dryer spends in repair and/or is otherwise nonoperational, the required manpower, and the energy required to return a dryer to wood veneer drying temperatures, present significant costs.
There is accordingly a need in the art for a wood veneer dryer wherein the inflow of cooler ambient air into the dryer and/or the outflow of gases from inside the dryer are controlled to reduce energy consumption by the dryer, prevent the build-up of pitch within the dryer, and/or prevent the outflow of gases containing V.O.C. from the dryer before treatment in the exhaust system.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.
The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools, and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.
To address the foregoing, the present invention provides removable baffle systems to mechanically seal a dryer and substantially restrict the inflow and/or outflow of gases from the input and output ends of the dryer and/or various dryer chambers. Methods of replacing and adjusting a baffle seal strip are further provided by the invention to address the foregoing.
One aspect of the present invention provides a baffle system for use with a dryer. The dryer includes at least one roller for supporting and conveying a material to be dried therethrough. The baffle system includes at least one dryer tube and a baffle removeably mountable to each dryer tube. Each dryer tube extends laterally from a first dryer wall to a second dryer wall inside the dryer, perpendicularly to a direction of travel of the material to be dried through the dryer. Each baffle comprises a body and at least one seal strip removeably attached to an end of the body. Each seal strip is positioned in sealing engagement with at least one roller when the baffle is removeably mounted inside the dryer.
In some embodiments, the baffle includes a baffle tube extending lengthwise through the body for receiving the dryer tube and removeably mounting the baffle inside the dryer.
In some embodiments, the baffle rests on the dryer tube when the baffle is removeably mounted inside the dryer. The baffle may comprise at least one baffle guide for guiding the baffle along the dryer tube when the baffle is removed from and/or inserted into the dryer.
In some embodiments, each dryer tube is vertically-aligned at one or more of an input end of the dryer, an output end of the dryer, an input end of a dryer chamber, and an output end of a dryer chamber.
In some embodiments, each dryer tube is attached at a first end to the first dryer wall and extends at least halfway between the first dryer wall and the second dryer wall. The dryer tube may be attached at a second end to the second dryer wall.
In some embodiments, the baffle is insulated.
In some embodiments, the baffle system includes at least one dryer guide attached to the dryer for supporting and guiding each baffle when the baffle is inserted into and/or removed from the dryer.
In some embodiments, the at least one seal strip includes a first seal strip attached to a first end of the body. The at least one seal strip may further include a second seal strip attached to a second end of the body opposed to the first end.
In some embodiments, each dryer tube is positioned such that when the corresponding baffle is removeably mounted thereto the first seal strip is positioned in sealing engagement with the at least one roller of the dryer.
In some embodiments, each dryer tube is positioned between an upper pinch roll assembly of the dryer and a lower pinch roll assembly of the dryer such that when the corresponding baffle is removeably mounted thereto the first seal strip is positioned in sealing engagement with a lower pinch roller of the upper pinch roll assembly and the second seal strip is positioned in sealing engagement with an upper pinch roller of the lower pinch roll assembly.
Another aspect of the present invention provides a dryer comprising a baffle system. The dryer includes at least one roller for supporting and conveying a material to be dried therethrough. The baffle system includes at least one dryer tube and a baffle removeably mountable to each dryer tube. Each dryer tube extends laterally from a first dryer wall to a second dryer wall inside the dryer, perpendicularly to a direction of travel of the material to be dried through the dryer. Each baffle comprises a body and at least one seal strip removeably attached to an end of the body. Each seal strip is positioned in sealing engagement with at least one roller when the baffle is removeably mounted inside the dryer.
Another aspect of the present invention provides a baffle system for use with a dryer. The dryer includes at least one roller for supporting and conveying a material to be dried through the dryer. The baffle system includes at least one baffle removeably mountable to the dryer. Each baffle includes a body and at least one seal strip removeably attached to an end of the body. Each seal strip is positioned in sealing engagement with the at least one roller when the baffle is removeably mounted inside the dryer.
In some embodiments, each baffle is vertically-aligned at one or more of an input end of the dryer, an output end of the dryer, an input end of a dryer chamber, and an output end of a dryer chamber.
In some embodiments, each baffle is insulated.
In some embodiments, the baffle system includes at least one guide attached to the dryer for supporting and guiding each baffle when the baffle is inserted into or removed from the dryer.
In some embodiments, the at least one seal strip includes a first seal strip attached to a first end of the body. The at least one seal strip may include a second seal strip attached to a second end of the body opposed to the first end.
In some embodiments, each baffle is mountable inside the dryer such that the first seal strip is positioned in sealing engagement with the at least one roller of the dryer.
In some embodiments, each baffle is mountable inside the dryer such that the first seal strip is positioned in sealing engagement with a lower pinch roller of an upper pinch roll assembly of the dryer and the second seal strip is positioned in sealing engagement with an upper pinch roller of a lower pinch roll assembly of the dryer.
Another aspect of the present invention provides a dryer comprising a baffle system. The dryer includes at least one roller for supporting and conveying a material to be dried through the dryer. The baffle system includes at least one baffle removeably mountable to the dryer. Each baffle includes a body and at least one seal strip removeably attached to an end of the body. Each seal strip is positioned in sealing engagement with the at least one roller when the baffle is removeably mounted inside the dryer.
Another aspect of the present invention provides a method of replacing and/or adjusting a seal strip inside a dryer. The dryer includes at least one roller for supporting and conveying a material to be dried through the dryer. A first baffle is removed from the dryer by sliding the baffle through a manifold. A second baffle is inserted into the dryer by sliding the baffle through the manifold such that at least one seal strip of the second baffle is positioned in sealing engagement with the at least one roller of the dryer.
In some embodiments, the first baffle is removed from the dryer by removing a dryer tube from a first baffle tube of the first baffle and the second baffle is installed in the dryer by inserting the dryer tube into a second baffle tube of the second baffle.
In some embodiments, the first baffle is removed from the dryer by sliding the first baffle across a dryer tube inside the dryer and the second baffle is installed into the dryer by sliding the second baffle across the dryer tube.
In some embodiments, at least one seal strip is removed from the first baffle and at least one new seal strip is removeably attached to the baffle.
In some embodiments, the at least one seal strip is adjusted.
In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions.
Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed are to be considered illustrative of the invention rather than restrictive.
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. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.
Unless context dictates otherwise, “input end” (as used herein in relation to a dryer and components thereof) means the end wherein a material to be dried is introduced into one or more of the dryer, an input end seal chamber, a drying chamber, an intermediary chamber, and a cooling chamber.
Unless context dictates otherwise, “output end” (as used herein in relation to a dryer and components thereof) means the end opposite to the input end, i.e. the end wherefrom a dried material exits one or more of the dryer, an input end seal chamber, a drying chamber, an intermediary chamber, and a cooling chamber.
Unless context dictates otherwise, “direction of travel” (as used herein) means a direction in which a material to be dried travels from an input end to an output end of a dryer, i.e. the direction from left to right in view of the example embodiment shown in
Unless context dictates otherwise, “chamber” (as used herein) means one or more of a drying chamber, an intermediary chamber, and a cooling chamber.
Some embodiments of the present invention provide baffle systems and methods of replacing or adjusting worn seal strips for improving dryer safety and/or efficiency. The systems include one or more baffles removeably mounted to the dryer at one or more of an input end, an output end, an input end of a dryer chamber, and an output end of a dryer chamber. Each baffle has at least one seal strip for contacting a roller of the dryer to prevent gases from entering and/or exiting the dryer. The baffles are removable from the dryer so that the seal strips can be replaced and/or adjusted when the seal between a given seal strip and a contacting roller becomes compromised. To replace and/or adjust a seal strip, the baffle is removed from the dryer and a new baffle is installed in its place. Each seal strip of the new baffle contacts a dryer roller to prevent the inflow and outflow of gases. Thus, to replace and/or adjust a worn seal strip, normal operating conditions of the dryer need only be interrupted temporally since it takes an operator mere minutes to replace a worn baffle with a new baffle and the one or more seal strips of the removed baffle may be replaced and/or adjusted at the leisure of the operator, outside of the dryer. Also, the manpower required to replace the worn baffle with the new baffle and the energy required to return the dryer to normal operating conditions once the new baffle has been installed are minimal. Further still, dryer components, such as dryer rollers, jet tubes, and conveyor chains need not be removed from the dryer to access the worn baffle and install a new baffle.
A baffle system 100 in accordance with one example embodiment of the present invention is shown in
A conventional wood veneer dryer, such as dryer 10, may include an input end seal chamber 20 connected to an input end 12 of an elongated drying chamber 30 (see
As best seen in
System 100 includes one or more baffles 80 removeably mounted to a dryer at one or more of an input end, an output end, an input end of a dryer chamber, and an output end of a dryer chamber depending on the demands of the dryer and/or the operator. Baffle system 100 (and each baffle 80) is sized and dimensioned to seal openings at the dryer input and/or output ends. In the example embodiment shown in
Each baffle 80 includes a body 81 and one or more seal strips 82 removeably attached to body 81 for contacting a dryer roller to prevent gases from entering and/or escaping the dryer (see
Body 81 comprises an elongated shell that may define a tube 85 extending lengthwise through a middle of body 82 (see
Seal strip 82 is made of a flexible and/or durable material having a degree of heat resistance that is suitable for use in high temperature dryers, including, but not limited to, one or more of silicon, stainless steel, high temperature textiles (such as high temperature woven glass (e.g. woven glass blankets and woven glass cloth) and Nomex™ cloth), coated textiles (such as vermiculite-coated cloth, rubber-coated cloth, rubber-coated fibreglass cloth, neoprene-coated cloth, neoprene-coated fibreglass cloth), and impregnated high temperature textiles (such as graphite-impregnated high temperature textiles). Seal strip 82 may be removeably attached to body 81 of baffle 80 using one or more of bolts, clamps, or other means conventionally known.
To mount baffle 80 to a dryer, the dryer is provided with a tube 90 for each baffle 80 of system 100 at one or more of an input end, an output end, an input end of a dryer chamber, and an output end of a dryer chamber. In the example embodiment shown in
Each tube 90 is positioned such that when baffle 80 is removeably mounted thereto or thereon, seal strip 82 contacts a roller of the dryer. In the example embodiment shown in
Tube 90 is made of a ferrous or non-ferrous material, including, but not limited to, one or more of steel and stainless steel. Tube 90 is sized and shaped for a tight-tolerance fit inside tube 85 of body 81. In some embodiments, a high-temperature, anti-seize compound, including, but not limited to, grease, may be used to keep tubes 85 and 90 from rusting and/or corroding together when tube 90 is fit inside tube 85.
As a material to be dried is conveyed through a dryer, such as dryer 10, seal strip 82 of baffle 80 wears and the air seal established between seal strip 82 and the respective dryer roller is compromised. In the case of dryer 10, this allows gases containing V.O.C. to escape the dryer and/or ambient air to enter the dryer. To restore the air seal, baffle 80 may be mechanically removed from dryer 10 and seal strip 82 may be adjusted or replaced.
An input end dryer panel (substantially equivalent to input end dryer panel 11 shown in
To adjust or replace seal strip 82, baffle 80 may be removed from a dryer, such as dryer 10, by sliding baffle 80 along tube 90 through a delivery or return plenum or manifold 19a, past a door post 19b, to outside the dryer. A support 110 (shown schematically in
To facilitate movement of baffle 80 along tube 90, at least one guide 120, such as a roller or any other suitable means conventionally known, may be provided. In some embodiments, the at least one guide 120 is attached to the dryer frame proximate to upper end 83 and/or lower end 84 of baffle 80 at a first end 86 and/or a second end 87 of baffle 80 when baffle 80 is installed inside the dryer. Persons skilled in the art will recognize that the at least one guide 120 may be provided in a number of suitable arrangements to support and guide baffle 80 as it is installed on and/or removed from tube 90.
Interpretation of Terms
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”, “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 substrate, assembly, device, manifold, etc.) is referred to above, 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 described herein.
Specific examples of systems, methods, and apparatus have been described herein for purposes of illustration. These are only examples. The technology provided herein can be applied to systems other than the example systems 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 addressee, 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.
It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, omissions, and sub-combinations as may reasonably be inferred. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.
This application claims the benefit of and convention priority from U.S. patent application No. 62/174,119 entitled REMOVABLE BAFFLE SYSTEMS FOR WOOD VENEER DRYERS AND METHOD OF REPLACING OR ADJUSTING BAFFLES OF SAME and filed on 11 Jun. 2015 which is hereby incorporated herein by reference for all purposes.
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