Patent Application
20210071874
The following description relates generally to a door for a cooking appliance and, more specifically, to a door construction for use in a self-clean cooking appliance.
During a cooking process, the interior of the appliance, such as an oven, may become soiled in various ways. Residues from cooked food and condensation of vapor components stick to the walls of the cooking cavity, especially towards the bottom. Thus, many cooking appliances include a self-clean feature. For example, in an oven with a self-clean feature, the interior of the oven is subjected to high temperatures. This is known as pyrolytic cleaning. During pyrolytic cleaning, a broil burner or heating element located near the top of the oven cavity and a bake burner or heating element is turned on to raise and hold the temperature within the cavity to the self-clean temperature. This heating process is conducted from about two to four hours. This long-lasting, high-temperature heating subject the soil and residue sticking to the oven cavity to a thermal cracking process. The soil and residue are then converted into decomposition products, such as water, short-chained hydrocarbons, aromatics, and ashes. Gaseous products can be carried out of the oven by a ventilation system during the self-clean operation, and once the self-clean operation has completed, the remaining residue can be easily removed from the cavity in the form of ashes.
Standards agencies, such as Underwriters Laboratories (UL) and Canadian Standards Association (CSA), have regulations in place regarding allowable surface temperatures present on the oven exterior, including the oven door, during high temperature events, such as during a self-clean operation. The outer surface of the door must be kept at a sufficiently low temperature. And, as users prefer lighter and thinner oven doors, it becomes increasingly challenging to keep the doors cool enough to meet such agency specifications.
The following presents a simplified summary in order to provide a basic understanding of the embodiments described herein. This summary is not an extensive overview nor is it intended to identify key or critical elements. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
According to one embodiment, a door for a self-clean cooking appliance includes a glass pack comprising a first glass pane and a second glass pane; and a third glass pane positioned in a spaced apart relationship from the glass pack, wherein the third glass pane is a decorative glass pane, wherein at least one of the first glass pane and the second glass pane is a low-emissive glass pane, and wherein a first open space is provided between the second glass pane and the third glass pane and a second open space is provided between the first glass pane and the second glass pane, a thickness of the first open space being greater than a thickness of the second open space.
According to another embodiment, a door for a self-clean cooking appliance includes: an outer door panel; an inner door panel spaced from the outer door panel; a wool shield positioned between the outer door panel and the inner door panel; and no more than three glass panes positioned between the outer door panel and the inner door panel, wherein the three glass panes include an outermost glass pane, a central glass pane, and an innermost glass pane, and wherein a distance between the outermost glass pane and the central glass pane is greater that a distance between the innermost glass pane and the central glass pane.
According to another embodiment, a door for a self-clean oven includes: a decorative glass pane; a glass pack having at least one low-emissive glass pane, the glass pack being spaced from the decorative glass pane; and a wool shield positioned around a periphery of the glass pack, the wool shield being spaced from the decorative glass pane, wherein a bottom portion of wool shield is sloped to facilitate high velocity air flow from a bottom of the door into a space behind the decorative glass pane.
Other features and aspects may be apparent from the following detailed description, the drawings, and the claims.
Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals can be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience.
Example embodiments are described and illustrated herein. These illustrated examples are not intended to be a limitation on the present embodiments. For example, one or more aspects of the system can be utilized in other embodiments and other types of appliances. Example embodiments of a self-clean door for a cooking appliance will be described more fully hereinafter with reference to the accompanying drawings. Such doors used for insulation from high temperatures may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of a door constructed for use in a self-clean cooking appliance to those of ordinary skill in the art. Like, but not necessarily the same, elements (also sometimes called modules) in the various figures are denoted by like reference numerals for consistency. Terms such as “first,” “second,” “outer,” and “inner” are used merely to distinguish one component (or part of a component or state of a component) from another. Such terms are not intended to denote a preference or a particular orientation.
As shown on
The door 60 includes a transparent section 65, such as a glass window in order for a user to see into the oven cavity 30 during operation of the oven without opening the door 60. In order to pass agency requirements, oven doors must maintain a sufficiently low exterior temperature during the highest temperature operations of the oven. As noted above, in ovens that include self-clean features, the temperature within the oven cavity can reach up to 850-degrees Fahrenheit. Accordingly, an oven door construction for a self-clean oven must be capable of blocking the extreme heat within the oven cavity 30 from reaching an outer surface of the door 60. Conventionally, this was accomplished by constructing the oven door to include at least three heat reflective glass panes, with at least one of these glass panes acting as an air wash (i.e., having convective air flow on both surfaces of the glass pane), and a decorative glass pane, totaling at least four separate glass components in the door for cooling a door of a certain thickness, for instance 45 mm, to agency standards.
Turning now to
The insulation 150 is positioned around a periphery of the glass pack 125 so as to substantially frame the glass pack 125 and fill remaining space between the wool shield 160 and the inner door panel 110. The insulation 150 is preferably made from glass wool material. Glass wool is constructed from fibers of glass arranged into a texture similar to wool. This manufacturing process traps small pockets of air between the glass fibers, which results in high thermal insulation properties. Dimensions of the glass wool insulation 150 correspond with dimensions of inner door panel 110 and wool shield 160 such that the glass wool insulates the outer assembly 185 from heat absorbed by the inner door panel 110. Additionally, as will be shown and described in greater detail below, at least one outer portion of the wool shield 160 is sloped or angled in order to direct air flowing from an exterior portion of the door assembly 100 into and through an interior region of the door assembly 110. More specifically, the slope of the outer portion creates an increased space or opening for cool air to enter the door assembly 100. Further, the wool shield 160 has a substantially smooth profile to facilitate smooth airflow over the wool shield 160. Thus, cool air entering a bottom opening of the door assembly 100 can flow past the wool shield 160 and exit from a top opening of the door assembly 100, such as through slots formed in the inner door panel 110. This airflow assists in removing heat from the door assembly 100 and acts an additional insulation layer between the inner door panel 110 and the outer assembly 185.
The glass pack 125 positioned between the inner door panel 110 and the wool shield 160 includes a first glass pane 120, a frame 130, and a second glass pane 140. The frame 130 is positioned between and around outer edges of the first glass pane 120 and the second glass pane 140 in order to maintain the glass panes 120, 140 in a spaced-apart and parallel relationship within the door assembly 100. In the present embodiment, the frame 130 holds the first and second glass panes 120, 140 approximately 8-10 mm apart, as better seen in
Turning now to the outer assembly 185 of the door assembly 100, the outer assembly 185 is coupled to the inner assembly 115 in a parallel, spaced-apart relationship. More specifically, the outer assembly 185 includes an outer door panel 190 that can be secured directly to the inner door panel 110 at their respective edges to form an interior region therebetween. The outer door panel 190 can be made of a stainless steel, an enameled steel, or any other suitable material. A handle 200 is secured to a front portion of the outer door panel 190, which allows a user to easily open and close the door assembly 100. The handle 200 can be secured in any desired manner, such as via fasteners. Coupled to a back portion of the outer door panel 190 is a third glass pane, or an outer glass pane, 180. The outer glass pane 180 can be secured to the outer door panel 190 via any suitable manner, such as with an adhesive suitable to withstand high oven temperatures. The outer glass pane 180 is a decorative glass pane that can be coated with a non-reflective coating over at least a portion of its outer face, the side intended to face the user. For example, the outer face of the outer glass pane 180 can be tinted to facilitate the direction of thermal energy back into the oven cavity and away from an exterior surface of the door assembly 100. This minimizes heat loss inside the cooking cavity and also reduces the temperature of the outer face of the outer glass pane 180. Alternatively, or in addition, reflective insulation paint can be applied to an inner face of the outer glass pane 180.
The oven door assembly 100 is thus constructed with no more than three glass panes: a decorative outer glass pane 180 and two low-emissive, or heat reflective, glass panes 120, 140; or a decorative outer glass pane 180, a low-emissive, or heat reflective, glass pane 120 and a plain, uncoated glass pane 140. The decorative glass pane 180 is the outermost glass pane with respect to the cooking cavity; the heat reflective glass pane 120 is the innermost glass pane; and the central glass pane 140 can be either a heat reflective glass pane or an uncoated glass pane. Traditional oven door designs for self-clean ovens require at least two glass panes, typically three, each of which have a heat reflective coating and/or at least one air wash glass pane in addition to an outermost, decorative glass pane—at least four glass panes in total. Thus, due to having fewer components, i.e., no fourth glass pane or any hardware required to hold a fourth glass pane in place, the door assembly of
Turning now to
Airflow is, however, desired between the third or outer glass pane 180 and the second glass pane 140. As shown in
As shown in
The cool, ambient air from outside of the oven, or zone 320, flows through openings 280 at a bottom of the door assembly 100 to enter zone 350, which is an open space between the glass pack 125 and the outer, or decorative, glass pane 180. Aside from airflow, zone 350 is substantially empty, that is, it is free from any glass pane or other structure that could restrict, hinder, or otherwise slow the flow of air therethrough. Thus, a velocity of air flow through zone 350 is high. This high velocity is further aided by the smooth configuration of the wool shield 160, over which air flows when entering zone 350. In some conventional door assemblies, this space or distance between the decorative glass and the glass pack is small, i.e., less than 4-10 mm, and thus, leads to significantly lower velocity, and thus, less airflow behind the decorative glass 180. In other conventional door assemblies, an additional coated or uncoated glass pane is provided between the glass pack and the decorative glass pane. The presence of this additional, or fourth, glass pane restricts air flow between the glass pack and the decorative glass pane as air has to flow around the additional structure. Accordingly, air flow is slower and is thus, less efficient at cooling the decorative glass pane 180.
Heated exhaust air can exit the door assembly in various ways. In the present example, a portion of exhaust air enters into an inlet of an oven cooling system, while another portion is drawn into a main oven exhaust, which leaves the oven along with the main exhaust at 360. As shown, the oven exhaust 360 flows over a top portion of the door assembly 100 to exit the oven into the cool, ambient zone 320. Thus, in the present embodiment, the door assembly 100 is free from (i.e., does not include) top vents or openings 300. By not having any vents or openings in a top surface of the door assembly, hot air is prevented from entering the door and the eddy effect present in conventional door assemblies is eliminated.
The example embodiments described herein facilitate a reduced number of glass panes, including heat-reflective glass panes, and increased spacing behind the decorative glass pane, while maintaining a thin oven door construction, thereby improving or at least maintaining the temperature-insulation features as compared to conventional self-clean oven door designs. Reducing the number of glass panes present in the door assembly reduces both the component cost and the weight of the oven door design. Moreover, an overall oven door thickness of about 40-45 mm, preferably about 42 mm, can be maintained while increasing the open airflow space behind the outer, decorative glass pane to be about 20-24 mm, preferably about 22 mm, which is approximately half of the thickness of the overall oven door assembly.
Although embodiments described herein are made with reference to example embodiments, it should be appreciated by those skilled in the art that various modifications are well within the scope and spirit of this disclosure. Those skilled in the art will appreciate that the example embodiments described herein are not limited to any specifically discussed application and that the embodiments described herein are illustrative and not restrictive. From the description of the example embodiments, equivalents of the elements shown therein will suggest themselves to those skilled in the art, and ways of constructing other embodiments using the present disclosure will suggest themselves to practitioners of the art. Therefore, the scope of the example embodiments is not limited herein. The disclosure is intended to include all such modifications and alterations disclosed herein or ascertainable herefrom by persons of ordinary skill in the art without undue experimentation.
