Patent Publication Number: US-2021170624-A1

Title: Treated laminated veneer lumber and method of making same

Description:
FIELD 
     The present disclosure relates generally to lumber and more particularly to laminated veneer lumber that has been specifically treated after assembly and a related method for making the same. 
     BACKGROUND 
     Laminated veneer lumber (LVL) is an engineered wood product that uses multiple layers of thin wood assembled with adhesives. LVL is typically used for headers, beams, rafters, rim board and edge-forming material. LVL can be preferred over typical milled lumber in many instances. For example, LVL is manufactured to controlled specifications. In this regard, LVL can be manufactured to be stronger, straighter and more uniform as compared to conventional solid milled lumber. Further, due to its composite nature, LVL is much less likely than conventional lumber to warp, twist, bow or shrink. 
     While LVL can be useful in many applications a need still exists in the art to provide improvements. For example, LVL is typically installed in interior environments that are not exposed to weather. In addition, a need exists to provide a straighter, stronger and more consistent lumber solution that is simpler to make and can be readily applied to a wider range of applications. 
     The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. 
     SUMMARY 
     A method of making treated laminated veneer lumber (LVL) according to one example of the present disclosure includes obtaining assembled LVL. The assembled LVL comprises a plurality of layers of veneer wood assembled together with adhesive. The LVL is loaded into a pressure chamber. A vacuum is created in the pressure chamber thereby removing air from the plurality of layers of veneer wood of the LVL. Inorganic solution is added into the pressure chamber. The pressure chamber is pressurized to force the inorganic solution into the wood creating the treated LVL. 
     According to additional features, a predetermined amount of time is passed subsequent to pressurizing the pressure chamber to allow the inorganic solution to sufficiently absorb into the LVL. In one example, the predetermined amount of time is greater than 30 minutes. In another example, the predetermined amount of time is greater than 35 minutes. In still other examples, LVL can be successfully penetrated through the thickness of the LVL during pressure treatment in less time, such as but not limited to, 6 minutes. The inorganic solution is removed from the pressure chamber subsequent to waiting the predetermined amount of time. A vacuum is created in the pressure chamber subsequent to removing the inorganic solution from the pressure chamber. 
     In other features, the treated LVL is removed from the pressure chamber and placed onto a concrete pad for drying. Adding the inorganic solution can include adding a solution that includes at least one of micronized copper azole (MCA), copper azole (CA), ammoniacal copper quaternary (ACQ), ammoniacal copper zinc arsenate (ACZA) and chromatid copper arsenate (CCA). In one example, adding the inorganic solution comprises adding a solution that comprises all of the MCA, CA, ACQ, ACZA and CCA. In still other examples, the inorganic solution can additionally or alternatively include other vacuum pressure waterborne inorganic chemicals. 
     A treated laminated veneer lumber (LVL) according to the present disclosure is provided. The treated LVL comprises an assembled LVL treated with an inorganic solution in a pressure chamber. The inorganic solution is penetrated through an entire thickness of the assembled LVL. In some examples, the inorganic solution comprises a solution that includes at least one of micronized copper azole (MCA), copper azole (CA), ammoniacal copper quaternary (ACQ), ammoniacal copper zinc arsenate (ACZA) and chromatid copper arsenate (CCA). In one example, the inorganic solution comprises all of MCA, CA, ACQ, ACZA and CCA. The CA can comprise type A and B. The ACQ can comprise type B and C. The CCA can comprise type A, B and C. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a deck framework constructed with conventional lumber according to one Prior Art example; 
         FIG. 2  is perspective view of a deck framework incorporating treated LVL formed by the present teachings and constructed in accordance to one example of the present disclosure; 
         FIG. 3  is a sequence view of forming conventional LVL according to one Prior Art example; 
         FIG. 4  is a sequence view of making treated LVL according to one example of the present disclosure; 
         FIG. 5  is a perspective view of a treating process system wherein assembled LVL is placed into a vacuum pressure chamber and treated in accordance to one example of the present disclosure; and 
         FIG. 6  is a method of forming treated LVL according to one example of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     As will become appreciated from the following discussion, the present disclosure provides a treated LVL that is created using a novel method. While not so limited, the treated LVL disclosed herein is particularly useful in outdoor applications, such as but not limited to, deck framing. While traditional LVL has been successfully used in many applications such as indoor framing, such LVL is not particularly suited for outdoor use where weather elements such as moisture and sun can degrade the LVL over time. Moreover, other treated LVL offerings incorporate organic treatments and involve multiple steps for treating each layer of wood prior to assembly. 
     With initial reference to  FIG. 1 , a deck frame constructed in accordance to one prior art configuration is shown and generally identified at reference numeral  10 . The deck frame  10  can include a first plurality of joists  12  extending horizontally from a ledger  14  fixed to a house structure  18 . The first plurality of joists  12  extend laterally from the ledger  14  to an intermediate beam  20 . A second plurality of joists  22  extend laterally from the intermediate beam  20  to an outer beam or rim joist  26 . Intermediate posts  30  extend vertically from the intermediate beam  20  and can be secured to ground such as by way of concrete footings (not specifically shown). Outer posts  34  and interior posts  33  extend vertically from the outer beam  26  and can be secured to ground similar to the intermediate posts  30 . The deck frame  10  according to prior art can incorporate traditional joists  12  that are made from treated milled lumber. 
     Turning now to  FIG. 2 , a deck frame constructed in accordance to one example of the present teachings is shown and generally identified at reference numeral  50 . The deck frame  50  can include a plurality of joists  52 . The plurality of joists  52  extend horizontally from a ledger  54  fixed to a house structure  58  to an outer beam  66 . Outer posts  74  extend vertically from the outer beam  66  and can be secured to ground. The plurality of joists  52 , ledger  54  and outer beam  66  are all treated LVL formed by the method disclosed in the instant application. In one advantage over the deck frame  10  that incorporates conventional milled lumber, the plurality of joists  12  of the deck frame  50  are stronger. In this regard, the intermediate beam  20  used in the traditional frame  10  is eliminated. As such, the plurality of joists  12  can span further away from the house structure  58  all the way to the outer beam  66 . Additionally, intermediate posts, such as posts  30 , as well as interior posts  33  used in the traditional frame  10  are eliminated. The deck frame  50  incorporating the joists  52  formed from the novel method herein provides a straighter, stronger and generally more robust deck frame requiring less structural components over conventional deck frames. Because reduced amounts of joists are required to span extended lengths, deck frame designs are less constrained. 
     Turning now to  FIG. 3 , a process for making assembled LVL according to prior art is shown. As is known, LVL comprises multiple layers of wood veneers collectively shown at reference  100  and individually identified at references  102 A,  102 B,  102 C,  102 D and  102 E. It will be appreciated that while five layers are shown for simplicity, LVL may be constructed using more or less layers of wood. Typically, each of the wood veneers  102 A,  102 B,  102 C,  102 D and  102 E are aligned primarily along the length of the finished product. In some examples, each veneer  102 A,  102 B,  102 C,  102 D and  102 E are about 0.125 inches thick and made from rotary-peeled softwood (for example, but not limited to, southern yellow pine, Douglas fir, Aspen and Norway Spruce). 
     Each veneer  102 A,  102 B,  102 C,  102 D and  102 E is dried and graded. In most examples, the higher graded veneers are used for the face of the LVL while lesser graded veneers are arranged near the core. Once the veneers  102 A,  102 B,  102 C,  102 D and  102 E are dried they are individually passed under a curtain or roll coater where resin is applied. The resin can be phenol-formaldehyde (PF) or urea-formaldehyde (UF) or other material suitable for joining the veneers  102 A,  102 B,  102 C,  102 D and  102 E together. Once resin is applied to each individual veneer  102 A,  102 B,  102 C,  102 D and  102 E, the veneers are arranged in a stack  110  and fed into a hot press where the stack of veneers  110  are pressed into a solid billet thereby forming the assembled LVL. In some examples the solid billets may be rip cut into numerous strips  120 A,  120 B according to customer specification. By way of example, some LVL strips can be formed to beam length sections having 1 and ¾ inch by 11 and ⅞ inch cross-sections. Again, the description of the method of forming assembled LVL above is merely exemplary and other methods may be used for forming the assembled LVL within the scope of the present disclosure. 
     With reference to  FIGS. 4-6 , a method of making treated LVL according to the present disclosure will be described. With initial reference to  FIG. 4 , the instant method includes obtaining assembled LVL, such as the LVL  120 B described above with respect to  FIG. 3 . It is important to recognize that the instant method described herein uses pre-made LVL that has already been formed and assembled into veneers  110 . Next, the veneers  120 A are treated using a treating process system  200  as will be described in greater detail herein. Once the treating process  200  is complete, the treated LVL  120 C is created. 
     With particular reference now to  FIG. 5 , the treating process system  200  will be further described. The treating process system  200  can generally include a vacuum pressure chamber  210  having a door  212  that is selectively movable between open and closed positions. In the closed position, the pressure chamber  210  is air tight. A vacuum pressure source  230  is fluidly coupled to the pressure chamber  210  and configured to introduce a negative pressure (vacuum) or positive pressure into the pressure chamber  210 . A tray  220  can be included for slidably advancing stacks of LVL  120 A,  120 B into and out of the pressure chamber  210 . It will be appreciated that the vacuum pressure chamber  210  may be constructed differently within the scope of the present disclosure. It will further be appreciated that while the stacks of LVL  120 A,  120 B are shown in a particular arrangement and orientation in  FIG. 5 , they may be placed into the pressure chamber  210  in any configuration or orientation sufficient to adequately expose them to solution as explained herein. 
     With continued reference to  FIG. 5  and additional reference to  FIG. 6 , a method of making treated LVL will be described. The method is generally identified at reference  300  in  FIG. 6 . The method starts at  310 . At  312  assembled LVL (such as  120 A,  120 B) is obtained. The assembled LVL is loaded into the vacuum pressure chamber  210  at  314 . A vacuum is created in the pressure chamber  210  using the vacuum pressure source  230  at  320 . The vacuum pressure can be initiated by a controller (not specifically shown) operated by a worker. The vacuum pressure is used to remove air from the cell structure of the wood. 
     The pressure chamber  210  is then filled with solution at  322 . According to one example, the solution is inorganic solution that fully impregnates the assembled LVL with waterborne preservatives such as, but not limited to micronized copper azole (MCA), copper azole, type A and B (CA), ammoniacal copper quaternary, type B and C (ACQ), ammoniacal copper zinc arsenate (ACZA) and chromatid copper arsenate, type A, B and C (CCA). In still other examples, the inorganic solution can additionally or alternatively include other vacuum pressure waterborne inorganic chemicals. Next, the pressure chamber  210  is pressurized to force the solution through the assembled LVL at  324 . The pressure chamber  210  is pressurized for an amount of time required to sufficiently penetrate the solution through the thickness of the LVL. In some examples, the LVL is pressurized for greater than 30 minutes, such as 35 minutes to ensure full penetration of the solution through the thickness of the LVL. In other examples, the LVL can be successfully penetrated through the thickness of the LVL during pressure treatment in less time, such as but not limited to, 6 minutes. After the assembled LVL has been submerged with solution and pressurized for a period of time, the solution is removed (drained) from the pressure chamber  210  at  330 . In some examples the solution is returned back to a work tank where it can be used again. At  332  a final vacuum is introduced to the vacuum chamber  210  to remove excess solution. The treated LVL  120 C is then removed from the vacuum chamber  210  at  334 . In some examples the treated LVL  120 C can be placed on a concrete pad for a designated amount of time. The method ends at  340 . 
     The foregoing description of the examples has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.