The present invention is directed to a base construction for an air handling unit, and more particularly, to a base construction for an air handling unit having improved thermal properties.
Air Handling Units (AHUs) are one of several components in cooling and heating systems. They are an important component because the AHU houses a number of components used in the system to provide forced air for climate control in a particular structure. AHU components typically include motors, heating/cooling coils, and blowers as well as the required interface connections to effect such climate control.
The AHU is an enclosed interconnected framed panel structure. The framed panel structures include substantially thermally insulated panels that are supported between framing members, to define interconnected rectangular compartments. Although the panels are substantially thermally insulated, structural members are typically disposed between opposed skins to enhance the structural strength properties of the panel. Typically, the structural members and opposed skins, which are of metal construction, are secured together by metal screws. Therefore, despite the addition of insulating material between the skins, there is an amount of metal-to-metal contact between the opposed skins, which provides a continuous path of substantially reduced thermal insulative properties between the opposed skins. This reduction of thermal insulative properties adversely affects the efficiency of the cooling and heating system.
Similarly, the AHU is typically supported by robust base members, such as I-beams or C-channels. A layer of metal sheet often overlays the base members and serves as a floor for the AHU, with the floor being secured to the base members by metal fasteners. Despite the addition of insulating material layers and/or “air space” disposed beneath the floor and between the floor and the insulating material layers, there remains an amount of metal-to-metal contact between the base members and the floor which reduces the system efficiency of the cooling and heating system.
In addition, the atmospheric pressure inside the AHU can be significantly less than the atmospheric pressure outside of the AHU. Such difference in pressure subjects the floor to significant forces acting to draw the floor upwardly from the base members. Current measures to address this problem include using multiple mechanical fasteners to secure the floor to the base members and additionally significantly increasing the thickness of the floor. Not only do these measures increase the cost and weight of the AHU, but these measures fail to eliminate metal-to-metal contact between the base members.
Finally, the addition of through mechanical fasteners to secure the floor to the base members necessarily requires that apertures be formed in the floor to receive the fasteners. The floor is then susceptible to leakage of condensation that collects during operation of the AHU, despite attempts to seal the floor.
What is needed is an improved base construction that does not include a continuous path of substantially reduced thermal insulative properties between the floor and base members that is not susceptible to condensation leakage through the floor while permitting a decreased floor thickness.
The present invention relates to a base construction for an air handling unit including at least one base member having a top surface and a bottom surface opposite the top surface and a skin having opposed surfaces. An insulator having opposed surfaces is disposed between the top surface of the at least one base member and the skin, one surface of the insulator being securely connected to the top surface of the at least one base member and the other surface of the insulator being securely connected to one surface of the skin. The secure connections between the opposed surfaces of the insulator and the top surface of the at least one base member and one surface of the skin substantially preventing a continuous path of substantially reduced thermal insulative properties between the at least one base member and the skin.
The present invention further relates to a base construction for an air handling unit including at least one base member having a top surface and a bottom surface opposite the top surface and a skin having opposed surfaces. An insulator having opposed surfaces is disposed between the top surface of the at least one base member and the skin. One surface of the insulator is securely connected to the top surface of the at least one base member and the other surface of the insulator is securely connected to one surface of the skin. The secure connections between the opposed surfaces of the insulator and the top surface of the at least one base member and one surface of the skin substantially preventing a continuous path of substantially reduced thermal insulative properties between the at least one base member and the skin. At least one bracket is connected to the skin, the at least one bracket being disposed adjacent to the at least one base member. The at least one bracket has a leg disposed substantially parallel to the skin and at least partially overlapping the top surface of the at least one base member. A layer of an insulating material is applied over the skin, wherein the layer substantially fills a space between the leg and the top surface of the at least one base member with insulating material.
The present invention still further relates to a method of constructing a base for an air handling unit. The method includes providing at least one base member to support an air handling unit, the at least one base member having a top surface and a bottom surface opposite the top surface and securely connecting one surface of an insulator having opposed surfaces to the top surface of the at least one base member. The method further includes securely connecting one surface of a skin having opposed surfaces to the surface of the insulator opposite the at least one base member and securely connecting one or more bracket to the skin. The one or more bracket is disposed adjacent to the at least one base member, the at least one bracket having a leg disposed substantially parallel to the skin and at least partially overlapping the top surface of the at least one base member. The method further includes applying a layer of an insulating material over the skin, wherein the layer substantially fills a space between the leg and the top surface of the at least one base member with insulating material.
An advantage of the present invention is that it provides improved thermal insulative properties for air handling unit floors.
A further advantage of the present invention is that the number of parts is reduced.
A yet further advantage of the present invention is that the air handling unit floor is not susceptible to condensation leakage through the floor.
A still further advantage of the present invention is that the air handling unit floor is strengthened without increasing the floor thickness.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
One embodiment of a base 20 for an AHU 10 of the present invention is depicted in
After arranging the I-beam 22 and C-channel 24 base members, leg 30 of bracket 28 is secured to the upper surface of the I-beams 22, such as by a mechanical fastener 48, although adhesives, welding and other known methods may also be used. Preferably, leg 32 of bracket 28 extends downwardly for securing a panel 42, which is discussed below. Once the brackets 28 have been installed to the upper surfaces of the base members 22, 24, a layer of insulating material 26, such as polyiso foam board or polyisoboard, is secured atop each of the base members 22, 24. Polyisoboard is typically constructed of polyurethane material and has a density of between about 2 to about 6 pounds per cubic foot. It is preferred that the more dense polyisoboard is applied beneath portions of the floor that support heavy equipment due to the increased structural strength and stiffness of the more dense polyisoboard. However, it is desirable to user less dense polyisoboard where possible, as the thermal insulative value of the polyisoboard decreases as a function of increased density. Preferably, an adhesive layer 34 is applied to at least one corresponding surface between the base member 22, 24 and the insulating material 26 to secure the base member 22, 24 and the insulating material 26 together. Alternately, a layer of tape having an adhesive layer 34 applied to each opposed surface of the tape can be used to secure the base member 22, 24 to the insulating material 26.
Once the base member 22, 24 has been secured to the insulating material 26, skin 38 is then applied atop the insulating material 26, such as by adhesive layer 34, which can include a tape as previously discussed. In other words, mechanical fasteners are not required to secure the skin 38 to the insulating material 26, which eliminates the need to form apertures in the skin 38 to receive the mechanical fasteners. Alternately, a material, such as a bonding agent, which may be distinguished from an adhesive, can be applied between the insulating material 26, skin 38 and base member 22, 24 to provide a structural bond between the insulating material, skin and base member. As a result, although liquid can condense on the skin 38, there is no risk of leakage of the condensed liquid through the skin 38. Moreover, since the insulating material 26 prevents physical contact between the skin 38 and the base members 22, 24, there is no path of substantially reduced thermal insulative properties between the skin 38 and the base members 22, 24. Without the insulating material 26, a path of substantially reduced thermal insulative properties between the skin 38 and the base members 22, 24 otherwise occurs, as skin 38 and the base members 22, 24 are constructed of metal.
It is to be understood that metal fasteners that penetrate the skin 38, insulating material 26 and the base members 22, 24 provide a path of substantially reduced thermal insulative properties.
Similarly, as shown in
Referring to
Brackets 36 are preferably disposed so that there is an overlap 62 between leg 56 and a portion of a horizontal leg 60 of a base member, such as C-channel 24. Since bracket 36 is formed into short lengths, such as about 2-4 inches, it is possible to inject insulating material 52 to substantially fill the entire region between the skin 38 and leg 56 of bracket 36, including overlap 62. As a result, due to the stiffness of the insulating material 62, the overlap 62 between leg 56 of bracket 36 and the horizontal leg 60 of the base member 22, 24 provides structural stability to the skin 38, especially when the skin 38 is subjected to a negative pressure environment during operation of the AHU.
A negative pressure environment is encountered when the level of atmospheric pressure acting on the upper surface of the skin 38 is less than the level of atmospheric pressure acting on the lower surface of the skin 38. In other words, in a negative pressure environment, the skin 38 is urged away from the base member 22, 24. To counteract this effect, insulating material 52 disposed in the overlap 62 between leg 56 and leg 60 is compressed during this negative atmosphere pressure to resist movement of the skin 38 away from the base member 22, 24 caused by exposure of the skin 38 to the negative pressure. The length and number of brackets 36 required depends upon the stiffness of the foam material as well as the anticipated level of negative pressure and the amount of surface area of the skin 38. Thus, the bracket length can significantly deviate from the preferred 2-4 inch length range. Additionally, the length of the legs 54, 56, 58 are not necessarily the same dimension. By making use of the overlap 62, through fasteners are avoided which provides a skin 38 having no through metal connections extending from the base members 22, 24 to the skin 38, enhancing the thermal insulative properties of the base 20.
In an alternate construction as shown in
It is to be understood that brackets 36, 136 can include any construction that includes a leg or legs extending away from the skin 38 that overlaps a portion of a base member 22, 24. In the alternative, brackets 36, 136 can include any construction having a leg or legs extending away from the skin 38 that defines at least one channel 142 between the bracket 36, 136 and the skin 38.
An alternate construction of the base is shown in
It is to be understood that the construction as shown in
An alternate wall panel 242 construction as shown in
An alternate base construction is shown in
A vertical leg 102 of the angle 98 is positioned to contact the facing surface of skin 44 of the wall panel 242. Contacting corresponding surface of the opposite skin 44 of wall panel 242 is a vertical leg 96 of angle 92. A horizontal leg 94 of angle 92 is secured to the lower surface of leg 23 of base member 22 to better secure wall panel 242. To secure wall panel 242 in position, a removable fastener 106 can be directed through the vertical leg 102 of angle 98 and into wall panel 242. Preferably, the location of fastener 106 is above a predetermined maximum desired level of condensation that can be collected by the floor skins and angles 98. In other words, the aperture formed in the vertical leg 102 is above the fluid level reached when a predetermined maximum desired level of condensation is collected in the base construction of the present invention. It is to be understood that although structural support members are shown as C-channel or I-beam, these members could also be of any other geometry capable of supporting the floor skin and wall panels.
It is also to be understood that the structural support members could also be of any other geometry capable of supporting the floor skin and wall panels so long as the construction is configured to prevent a continuous path of substantially reduced thermal insulative properties between the structural support members and the floor skin. Additionally, although the insulating material is shown as being contiguous, i.e., single, continuous, unitary construction, the insulating material can also be provided in a discontinuous fashion, such as a plurality of segments of insulating material.
It is to be understood that the base construction of the present invention could include only the arrangement as shown in
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.