Patent Application
20110129205
The present disclosure relates to a fluid heater for an appliance. In particular, the present disclosure relates to an improved construction for a flow-through heater for heating water or other liquids and/or generating steam.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Appliances, such as dishwashers, clothes washers and water heaters, for example, employ a heater for heating water or other liquid that is used in the appliance. One type of heater used is a flow-through heater. An exemplary prior art flow-through heater is shown in
Mounted at locations on the exterior surface of the cylindrical member 12 are one or more temperature sensor assemblies 20 and 22. The temperature sensor assemblies 20 and 22 can house a temperature sensor, like a thermostat device or NTC device. In the example shown in
The electrical heating element 18 generates heat that is transferred to the cylindrical member 12 and, ultimately, to the fluid passing through the heater 10. A control system (not shown) regulates the temperature of the heating element 10 and/or fluid passing through the heater 10 based on feedback from the temperature sensor assemblies 20 and 22. A shroud 24 is located over the heating element 18 to cover and protect the heating element 18 and shield the surrounding area from the heating element 18.
Conventional flow-through heaters like that shown in
A flow-through heater of the present disclosure includes a tubular housing and a heating element. The tubular housing defines a passageway. The heating element is provided in the passageway and attached to the tubular housing. The heating element includes a resistive wire housed within an electrically insulating coating. The heating element includes a coiled wire portion defining a channel extending in a direction along a longitudinal axis of the tubular housing. The coiled wire portion defines a channel extending along the longitudinal axis to enable a fluid to flow therethrough. The coiled wire portion contacts the fluid when the fluid flows through the channel.
A flow-through heater of the present disclosure includes a metal cylindrical wall, a plurality of metal fin elements, and a heating element. The metal cylindrical wall includes an inner peripheral surface. The inner peripheral surface defines a passageway along a longitudinal axis of the cylindrical wall. The plurality of metallic fin elements extend inwardly from the inner peripheral surface and are located in the passageway. The heating element is provided on an outer peripheral surface of the metallic cylindrical wall.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Where applicable, corresponding reference numbers are used in the several Figures to identify like components.
Referring to
The fin elements 54 extend radially inwardly from an inner surface of the cylindrical wall 52. The fin elements 54 extend a predetermined length along the longitudinal axis 50 to support and position the heating element 44 in the passageway 56. The fin elements 54 may be integrally formed with the cylindrical wall 52 or attached to the cylindrical wall 52 by any securing means known in the art. The fin elements 54 and the cylindrical wall 52 may be formed of the same material, for example, aluminum, in one molding process. Alternatively, the fin elements 54 may be made of a material different from that of the cylindrical wall 52 and attached to the cylindrical wall 52 by any conventional securing means, such as welding or riveting.
The heating element 44 includes a coiled resistance wire and an electrically insulating coating 59 (shown in
The heating element 44 includes a coiled wire portion 57 and a pair of connecting portions 58. The coiled wire portion 57 includes a plurality of turns, each turn adjacent to one another to form a compact structure. Therefore, heat generated per unit length of the heating element 44 is increased as opposed to prior art heaters under similar operating conditions. The coiled wire portion 57 defines a channel therein and extends a predetermined distance along the length of the fin elements 54. The channel is coaxially aligned with the passageway 56 of the cylindrical wall 52. The pair of connecting portions 58 extend from opposing ends of the coiled wire portion 57 and connect the heating element 44 to an external power source (not shown).
An insulator 60 is provided between the heating element 44 and each of the fin elements 54 to insulate the heating element 44 from the fin elements 54. In addition to the electrically insulating coating 59 of the heating element 44, the insulators 60 provide further electrical insulation for the heating element 44.
Referring to
Referring to
The contact ends 72 of the terminal pins 68 are soldered to the contact ends 74 of the heating element 44 to ensure proper contact and electrical connection. A potting material 76 may fill in the cavity 70 after the soldering process to embed and insulate the contact ends 74 of the heating element 44 and the contact ends 72 of the terminal pins 68 therein.
The heater 40 according to the first embodiment of the present disclosure has a quick response and an improved heat transfer efficiency. The heating element 44 is located in the passageway 56. Fluid, which enters the passageway 56, flows around the heating element 44 and is in direct contact with the heating element 44. The fluid flows inside and outside the coiled wire portion 57. Heat generated by the heating element 44 is directly transferred to the fluid. No additional component is located between the heating element 44 and the fluid to absorb heat energy. Therefore, heat transfer efficiency of the heater 40 is improved. Moreover, the heating element 44 can be more easily attached to the tubular housing 42 by using the fin elements 54 and the insulators 60 without time-consuming welding process. Therefore, manufacturing process becomes easier, resulting in reduced manufacturing costs and increased throughput.
Referring to
The fin elements 88 extend from an inner surface 85 of the cylindrical wall 86 for supporting and positioning the heating element 84 in the passageway 87. The fin elements 88 each include an elongated body 89 and a pair of lateral fingers 91 extending laterally from the elongated body 89. The heating element 84 is provided between and clamped by the lateral fingers 91. The tubular housing 82 is made from a polymer material. Therefore, the heating element 84 can be directly placed on the fin elements 88. Because the fin elements 88 are made of an electrically insulating material, the heating element 84 can be attached directly to the elements 88. The number of components that form the heater 80 may be further reduced, resulting in a more simplified structure.
Referring to
Referring to
The tubular housing 102 includes a first part 112 and a second part 114 that jointly define a cylindrical shape and a passageway 116. The first part 112 and the second part 114 are made of a plastic material. The first part 112 defines two openings 120 for receiving the fuse assembly 106 and the temperature sensor assembly 108. An aluminum material is molded to the first part 112 of the tubular housing 112 in the openings 120 to provide an aluminum contact surface 121. A fuse (not shown) of the fuse assembly 106 and a temperature sensor (not shown) of the temperature sensor assembly 108 are provided at the aluminum contact surface 121. The temperature sensor may be a thermostat or an NTC device.
The fuse assembly 106 is mounted adjacent to an inlet of the passageway 116 and upstream from the heating element 104. The temperature sensor assembly 108 is mounted adjacent to an outlet of the passageway 116 and downstream from the heating element 104. The fuse assembly 106 and the temperature sensor assembly 108 each include a casing 122 and a pair of terminals 124 attached to the casing 122. The terminals 124 connect the fuse or the temperature sensor to a power source or a control device (not shown).
The casings 122 of the fuse assembly 106 and the temperature sensor assembly 108 each define a slot 123. The securing members 110 are in the form of a strap positioned in the slots 123 and wrapped around the tubular housing 102. The securing members 110 press the casings 122 of the fuse assembly 106 and the temperature sensor assembly 108 against the aluminum contact surface 121. As such, the fuse and the temperature sensor can contact the aluminum contact surface 121 to ensure proper detection of the temperature of the tubular housing 102 and the fluid flowing therethough.
Referring to
The two-piece structure of the tubular housing 102 facilitates soldering of the contact ends 117 of the heating element 104 to the contact ends 119 of the terminal pins 118. The two-piece structure also facilitates mounting of the heating element 104, the fuse assembly 106 and the temperature sensor assembly 108 to the tubular housing 102.
After the heating element 104, the fuse assembly 106, and the temperature sensor assembly 108 are mounted, the first part 12 and the second part 114 of the tubular housing 102 are joined, for example, by high frequency welding.
Referring to
While not specifically shown in
Referring to
The fin elements 138 jointly define a receiving space 141 (indicated by dashed line) for receiving the heating element 134 therein. The heating element 134 may be slid into the receiving space and supported by the fin elements 138. The heating element 134 includes a coiled wire portion 140 and a pair of connecting portions 142. The connecting portions 142 may extend through the cylindrical wall 136 of the tubular housing 132 to be connected to an external power source (not shown). Similarly, the heating element 134 is covered with an electrically insulating coating to insulate the heating element 134.
The cylindrical wall 136 defines a passageway 137. The passageway is generally divided by the coiled wire portion 140 into a first channel 144 and a plurality of second channels 146. The first channel 144 is surrounded by the coiled wire portion 140. The second channels 146 are defined by adjacent fin elements 138 and the outer surface of the coiled wire portion 140. Fluid flows in the first channel 144 and the plurality of second channels 146.
Referring to
The fuse assembly 156 and the temperature sensor assembly 158 are inserted into the hollow portions 162 and provided downstream from the terminal assemblies 154. A connector housing 159 receives a terminal 161 from each of the fuse assembly 156 and the temperature sensor assembly 158. The terminals 161 are connected to a control device (not shown).
The terminal assemblies 154 are provided adjacent to an inlet of the passageway 162 and upstream from the fuse assembly 156 and the temperature sensor assembly 158.
The heating assembly 152 includes a heating element 164 and a support member comprising a plurality of support rails 166 attached to the heating element 164. The support rails 166 each include an elongated body 168 and a pair of fingers 170 extending laterally from the elongated body 168. The fingers 170 clamp the heating element 164 therebetween. The support rails 166 are matingly inserted into slots 172 of the cylindrical wall 160. The slots 172 are formed on the inner surface 175 of the cylindrical wall 160 and extend along the length of the cylindrical wall 160.
The heating element 164 includes a coiled wire portion 174 and a pair of connecting portions 176 for connecting to the terminal assemblies 154. The connecting portions 176 may be in the form of nuts. When the heating assembly 154 is positioned inside the tubular housing 152, the connecting portions 176 are aligned with the terminal assemblies 154. By threading a screw 178 into a hole 179 of the cylindrical wall 160 and engaging the screw 178 to the nut-like connection portions 176, the terminal assemblies 154 are connected to the connecting portions 176.
Referring to
The heating element 204 is coiled around the cylindrical wall 206 and contacts an outer surface of the cylindrical wall 206. The heating element 204 includes a resistive wire and an electrically insulating coating on the resistive wire. An outer surface of the cylindrical wall that is in contact with the heating element is coated with an electrically insulating layer 212.
A temperature sensor assembly 214 and a fuse assembly 216 are provided at each end of the tubular housing 202. The temperature sensor assemblies 214 monitor the temperature of the cylindrical wall 206 and consequently the fluid flowing therethrough. The fuse assembly 216 protects the heating element 204 from overheating.
Securing devices 220 are provided around the cylindrical wall 206 to secure the temperature sensor assembly 214 and the fuse assembly 216 on the tubular housing 202.
The heater 200 of this embodiment improves heat transfer efficiency by providing the plurality of fins elements 208 in the fluid passageway 210. While heat from the heating element 204 is transferred indirectly to the fluid through the tubular housing 202, the heater 200 has an advantage of increasing heat transfer efficiency by increasing surface area for heat transfer.
The flow-through heater of the present disclosure provides a simplified structure to facilitate manufacturing of the flow-through heater, resulting in reduced manufacturing costs. Moreover, the simplified structure of the flow-through heater improves heater transfer efficiency and reduces heat loss and can more quickly heat the fluid to a desired temperature. While the flow-through heater has been described as a heater for heating fluids to a desired temperature, the flow-through heater may be configured as a steam generator without departing from the scope of the present disclosure. The flow-through heaters of the present disclosure may be used in, for example, dishwaters, laundry machines, or a SPA water heating systems.
This description is merely exemplary in nature and, thus, variations that do not depart from the gist of the disclosure are intended to be included within the scope of the disclosure. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the description and specific examples, while indicating the preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of this disclosure.
