Patent Application
20140230269
The present invention relates generally to the field of lavatory systems and, more particularly, to touch-free hand dryers that use proximity sensors to commence the blowing of air.
In an effort to reduce the waste and frequently the mess associated with paper toweling in public washrooms such as those found in high traffic areas like schools, libraries, airports, train and bus terminals, shopping centers, theaters, and sports venues, wall-mounted electric hand dryers have become prevalent. More recently, proximity sensors have allowed for touch-free hand dryers that can be activated automatically when a user places his hands in a drying zone adjacent the hand dryer; typically, below and/or in front of the hand dryer. For many installations, the hand dryer is mounted on a wall opposite the wash basin and, quite frequently, one or two hand dryers will be provided for a bank (more than two) of wash basins. As a result, a user after cleaning his hands must walk some distance to the hand dryer. This frequently results in water and/or soap dripping onto the floor as the user walks from the wash basin to the hand dryer. As there are typically more wash basins than hand dryers, it is possible that water could pool on the floor during high use periods. The accumulated water can create a slippery and, consequently, potentially unsafe condition. Additionally, the hand dryer can blow water from the user's hands onto the floor during the drying process further adding to the amount of water that accumulates on the floor. Moreover, water and/or soap can accumulate on the countertop supporting the wash basin which can be unsightly, if not quickly addressed. Additionally, the accumulation of water and/or soap on the floor and/or countertop may lead to germ-infested areas thus posing additional health risks as well as creating discomfort for users that are particularly germ sensitive.
One proposed solution is described in U.S. patent application Ser. No. 12/233,466, which is assigned to Bradley Fixtures Corporation, the assignee of this application and which is incorporated herein by reference. The aforementioned application describes a lavatory system in which a hand-washing station has a wash basin, a faucet, and an electric hand dryer. The integration of these components into a single wash station alleviates the need for a user to leave the wash station to access a hand dryer. That is, the hand dryer is adjacent the wash basin and (heated) air is blown into an area generally above the wash basin. Accordingly, a user can water and soap his hands in a conventional manner and then move his hands to the drying zone of the hand dryer. The user's hands do not need to leave the wash basin for the hands to be exposed to the drying air. Hence, water does not drip onto the floor as the user presents his hands to the dryer and water removed from the hands is blown into the wash basin rather than onto the floor.
The lavatory system described in the aforementioned application provides a significant improvement over conventional lavatory systems. However, the present inventor has discovered that many users of such an integrated wash station do not slide their hands over from below the faucet to the drying zone of the hand dryer. The inventor has found that some users, so conditioned to extract their hands from the wash basin entirely, will remove their hands from the wash basin and then present their hands to the front of the drying zone. As the hand dryer is activated when one or more proximity sensors sense the presence of the user's hands, it has been found that such a front-presentment can result in splashback of water onto the clothes of the user, the floor, or the countertop.
The present invention is directed to a hand dryer in which the point of entry into a drying zone is detected and used to selectively activate a delay before the hand dryer is activated. While not so limited, in one embodiment, the hand dryer is part of an integrated lavatory system having a wash basin with a faucet operably connected to the wash basin and a soap-dispensing system having a spout operably connected to the wash basin. The hand dryer defines a hand-receiving cavity above the wash basin so that a user does not need to remove his hands from the wash basin to place his hands in the hand-receiving cavity. The hand-receiving cavity has a top portion with an air outlet, and a bottom portion with an air outlet. A blower provides a volume of air to the air outlets which is ultimately presented to the hand-receiving cavity. Multiple proximity sensors are operably connected to the blower and turn the blower on and off when triggered by an object, i.e., detection of the user's hand(s). In one embodiment, a first proximity sensor is positioned adjacent a side of the hand-receiving cavity and thus senses the ingress of a user's hands into the hand-receiving cavity from the side. A second proximity sensor is positioned adjacent the front of the hand-receiving cavity and senses the ingress of a user's hands into the hand-receiving cavity from the front. Depending upon which sensor detects the user's hands, one of two different delays is observed before the blower is caused to force air to the air outlets. In a preferred implementation, a longer delay is observed if the second proximity sensor detects the user's hands.
In an alternate embodiment, each of the sensors has non-overlapping fields-of-view so that only one of the two sensors can detect the presentment of the user's hands.
In another alternate embodiment, detection by the first sensor results in a delay between zero and 300 milliseconds (ms) whereas detection by the second sensor results in a delay between 200 ms and 800 ms, and the delay resulting from detection by the second sensor is preferably selected to exceed the delay resulting from detection by the first sensor.
In a further embodiment, the two aforementioned sensors are replaced with a single sensor capable of discriminately sensing side-presentment or front-presentment of the user's hands to the hand-receiving cavity.
In another embodiment, an air filter and filter flow sensor are also provided.
These and other aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
A clear conception of the advantages and features constituting the present invention and of the construction and operation of typical mechanisms provided with the present invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings accompanying and forming a part of this specification, wherein like reference numerals designate the same elements in the several views, and in which:
The present invention will be described with respect to a hand dryer that is part of an integrated lavatory system also having a wash basin, a water faucet, and, optionally, a soap dispenser. However, it is understood that the present invention is applicable with stand-alone hand dryers, such as conventional wall-mounted hand dryers, and may also be desirable for other types of dryers in which it is desirable to delay commencement of a drying cycle based on the presentment of an object for drying to a drying chamber, cavity, or zone. In one preferred embodiment, the present invention is applicable with an integrated lavatory system such as those described in U.S. patent application Ser. Nos. 12/233,466 and 13/122,368 and herein incorporated by reference; however, as noted above, the invention is not so limited.
Turning now to
A soap dispensing system 26 is near the faucet 24 and in the wash basin 20. The soap dispenser 26 includes a spout 28 and a soap-dispensing sensor (located behind sensor window 29) to detect an object, such as a user's hand 166 (See, e.g.,
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Bottom nozzles 160b are provided, again, preferably by molding into the lower plenum 144. Lower nozzles 160b, like the upper nozzles 160a, preferably have protruding frustoconical nozzle tips 162b each of which has a nozzle hole 164b therethrough. The shape of the nozzle tips 162b on the lower plenum 144 further acts as a flood prevention mechanism 40 to protect the motor 74.
The hand-dryer blower 71, motor 74, and motor housing 70 are best shown in
The intake air portion or lower portion of the motor housing cap 82 is configured with a solid center section 95 surrounded by a circular pattern of holes 94. This configuration is spaced at a distance similar to the half wave length of the fan blade passing frequency of the fan motor 74. As a result, acoustical waves are reflected off of the solid center section 95 on the bottom of the housing cap 82 at a fan cowling and the acoustical foam 83, and eventually propagate through the circular hole pattern 94 in an attenuated manner.
A filter or intake cover 96 may also be provided in the housing 70 to contain or to hold the filter 84 in place. To further attenuate sound generated by the fan motor 74, insulation or acoustical foam 97 is placed on the inside of the intake cover 96. The cover 96 is preferably further configured to redirect the intake air 90 degrees from the axial center of the fan 76 and motor 74. This design promotes reflection of acoustical waves off of the noise-reducing acoustical foam 97. A wire or other locking mechanism 87 is provided to keep the filter cover 96 in place.
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The frame 120 and drain pipe 127 are preferably covered by a lavatory system cover 130 (as best seen in
In a preferred embodiment, upper and lower nozzle tips 162a, 162b connected to the nozzles 160a, 160b emit high-speed colliding columns of air to shear water off the user's hand. The tips, holes, and resulting air columns are spaced and calibrated in such a way as to reduce forces on the user's hand which would otherwise move the hand toward the upper or lower plenums or the side surfaces. As mentioned, one way of accomplishing this spacing and calibration is to have the axis of the air flow from upper plenum 142 nozzle holes 164a angled about 1 degree from vertical and aimed toward the cavity back wall 60 (
In one embodiment, the nozzles 160a, 160b preferably have tips 162a, 162b that are pointed protrusions that help pull static an into the air columns, see, e.g.,
As discussed, in one embodiment, the nozzles and holes on the top blade and the nozzles and holes on the bottom blade are at different angles from the horizontal plane and vertically aligned with one another so that the collision of the upper and lower streams of air provide a unique air flow pattern. This configuration preferably helps to generate an s-shaped airflow pattern. However, in another alternative embodiment, the holes and nozzles are lined up directly across the cavity from each other.
In one embodiment, the preferred bidirectional or dual-sided air flow dryer uses 1600 watts (or 13.7 amps) and will dry hands in about 15 seconds at 80 decibels (dB) with 70 cubic feet per minute (CFM). In this embodiment, the dryer runs off a 120V outlet and requires a dedicated 20 ampere (amp) circuit. Ground fault interruption (GFI) circuit protection is preferred. It is understood, however, that the invention is not limited to the above-referenced parameters. For example, it is contemplated that the dryer could run on a 15 amp circuit.
Referring now primarily to
In one preferred embodiment, the LEDs 108a-m are operably connected to the hand dryer 50. For example, LEDs 108a-d continuously illuminate the hand-receiving cavity 52 at a low intensity level when a sensor does not detect the presence of an object for drying, i.e., the cavity is not in use or in “stand-by”. However, when a sensor detects that an object for drying has entered into the hand-receiving cavity 52, and during dryer 50 activation, preferably the LEDs 108e-h and 108i-l also illuminate cavity and thus increase the overall intensity level of light in the cavity. In another embodiment, LEDs 108a-d do not begin to illuminate the cavity until the soap is dispensed or the water begins to flow in the basin.
In a preferred embodiment, when a staff member wishes to clean and service the lavatory system 10, the staff member may engage a service mode. Here the LEDs 108a-d and 108e-h continuously illuminate the hand-receiving cavity 52. Activation of hand dryer 50 is also suppressed by communication between controller 78 and controller 99. In one embodiment, service mode activation is accomplished by triggering a sensor, e.g., the right-most sensor 103d in the upper portion of the hand-receiving cavity 52, for an extended time period. Thus, if this one sensor consistently detects an object for drying in the hand-receiving cavity 52, the hand dryer 50 is disabled for about 30 to 60 seconds and some of the LEDs, e.g., LEDs 108e-h, may be illuminated at a high-intensity level. This allows the hand-receiving cavity 52 to be temporarily cleaned without further engaging the hand dryer 50.
The LEDs, e.g., 108i-l, may flash in certain ways when the service mode has been started and/or is about to end. For example, in one embodiment, prior to the service mode, one row of four white LEDs provides lower level illumination of the hand dryer cavity. However, if the right-most sensor is triggered within the last 2 seconds, and if a hand is placed over the right-most sensor for the period of 3 seconds, a row of four amber LEDs will rapidly flash twice to designate that the unit is entering the service mode. At the same time, a second row of four white LEDs will turn on to increase the illumination of the hand cavity for approximately 30 seconds to assist in cleaning. After approximately 25 seconds from when the service mode was started, the row of four amber LEDs will flash three times to indicate that the service mode cycle is nearing completion. At the end of the service mode cycle (5 seconds after the four amber LEDs flash three times or about 30 seconds in total service cycle length), the second row of white LEDs will turn off and the hand dryer cavity will remain lit at the lower level of illumination by the first row of four LEDs.
In one embodiment, the service mode includes a controller 78, e.g., a microcontroller, with a programmed touchless cleaning mode feature wherein if one sensor is the only sensor activated within the last two seconds and if activated continuously for about three (3) seconds, the hand dryer 50 will enter the mode to allow cleaning of the hand dryer 50. This mode lasts for about 30 seconds, during which dryer activation is suppressed, and then the controller will return the system to normal operation. The controller will flash the LED lights twice when entering the cleaning mode and three times when approaching a time near the end of a cleaning cycle which is approximately 25 seconds into an about 30 second cleaning cycle. If the cleaning mode is longer in another embodiment, the lights will flash three times, 5 seconds before the end of the cleaning cycle.
The sensor detection modules 105a and 105b utilize an internal triangulation algorithm to sense IR light, 106a and 106b respectively, when an object for drying is in the sensor's field of view. When a user's hand 166 enters the hand-receiving cavity 52, the sensor detection modules 105a and 105b output an electrical signal (e.g. a 5 volt signal). This signal is used by the controller 78 to determine whether to activate the hand dryer (50) and LED lights 108e-l (see
A programmable unit may be present on the sensor control board 100 and/or motor control board 98 and preferably includes a time-delay mechanism, for example, in communication with an on/off switch for the motor 74. In this embodiment, when one of the sensors 103a-d is activated by an object for drying, e.g., a user's hands, in the hand-receiving cavity 52, the controller 78 rechecks the activated sensor multiple times to validate that hands are in the hand-receiving cavity 52. Then the delay mechanism allows users to enter their hands 166 fully into the hand-receiving cavity 52 prior to the hand dryer motor 74 achieving full speed. This minimizes the potential of any splashing of water back on the user as a result of the fully active hand dryer imposing a shearing action on water present on the user's hands. There may be additional sensors (not shown) that may inhibit the dispensing of water or soap or activation of the dryer when a critical water level is reached in the wash basin and thus prevent overflow, flooding, and/or motor damage.
In another embodiment, there is communication between the faucet sensor controller and the dryer sensor controller. For example, when the faucet is used, the lights on the dryer go from off to on, e.g., to white. This feature could be used to indicate to the user that the user should move from the faucet to the dryer next, and thus make the wash station use more intuitive. This feature could also lock the faucet off while the user's hands are being dried. This would save water as it would truncate the faucet turn off time. It would also eliminate any splashing due to the dryer air flow through the basin.
In one embodiment, multiple distance sensors 103a-d utilize triangulation one at a time and from left to right in their field of view to detect an object for drying. These sensors are preferably positioned so they are recessed in the upper portion 53 and aimed vertically into the hand-receiving cavity 52. Recessing is minimal, however, to avoid adversely impacting sensor operation. In one embodiment, the sensor board 100 is programmed to check all sensors at about 130 millisecond (ms) intervals. When a sensor flags a detection, it is then rechecked fifteen times over about a 15 ms period to ensure the detection was not a false trigger.
The temperature rise of the air during a drying cycle is dependent upon how long the user keeps the hand dryer 50 activated. Since the system 10 does not use an auxiliary air heater, the air temperature rise is a result of the heat generated by the inefficiency of the motor 74. The other factor dictating the motor temperature rise is how frequently the motor 74 is activated. In a high usage environment (airport, sports arena, etc.), the motor 74 will not typically cool down very much between cycles and the air temperature rise experienced by the user will be significantly higher than that of a hand dryer which operates infrequently. The following chart shows some typically-expected temperature rises.
In one embodiment, additional safety and cleaning features may be present. For example, UV lighting or some other sterilization technique to disinfect the hand-receiving cavity 52 may be provided. Further, only one drain may be provided between the wash basin 20 and outside of hand-receiving cavity 52 to eliminate the need for another device to catch water from the dryer 50 that must be emptied and can collect harmful molds or germs. Certain dryer components, like the nozzles 160a, 160b, may have an antimicrobial additive molded into the plastic. Further, the entire wash basin 20 and hand-receiving cavity 52 may be constructed, in part, of an antimicrobial material or may be coated with such a material during manufacture.
In one embodiment, a second row of holes, a slot, and a port are present to provide a lower velocity air stream to further minimize water splashing onto a user.
In the embodiment shown in
A bottom portion 255 includes a lower air outlet 256. The bottom portion 255 is formed, in part, by a bottom wall or side 259. The bottom portion 255 of the hand-receiving cavity 252 also includes a back wall or side 260, front wall or side 261, and side wall 262. A front ledge 263 is integral with the front wall 261. The hand-receiving cavity 252, therefore, is preferably configured to have a front opening 264 and a side opening 265 (shown on the left side). In this embodiment, the dryer's configuration and placement preferably allows the user to easily transition the hands from the wash basin to the dryer without dripping water onto the floor.
In one preferred embodiment, a mechanism 240 for preventing flooding and damage to the hand dryer motor is provided as well as to prevent water blown from a user's hands from falling to the floor and creating a slip hazard or unsanitary conditions. The mechanism 240 may include a flood relief rim 244 located on for example, the left side of the hand-receiving cavity 252 at the opening 265. The flood relief rim 244 is provided below the lower portion's air outlet 256 and the nozzle tips 262b as shown. Thus, water flows over the flood relief rim 244 and not down the nozzle holes 264b and into the motor (not shown). In addition, another motor protection mechanism 240 may be the frustoconical lower nozzle tips 262b which resist the entry of water.
Other preferred embodiments of the hand dryer 250 may include a side wall 262 on the left side and an opening 265 on the right side. In yet another preferred embodiment, the hand dryer 250 may include both a left side, side wall and a right side, side wall.
The primary components of the inventive lavatory system including the dryer bottom wall, a back wall, and single side wall are preferably formed from a plastic and/or resin material.
In one embodiment, the system components may be formed from a solid polymeric and/or a polymeric and stone material. In another embodiment, the system components may be manufactured from Terreon® or TerreonRE® which are low emitting, e.g., Greenguard™ materials and available from the Bradley Corporation of Wisconsin.
In another embodiment, as best shown in
As described above with respect to
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Therefore, in accordance with another embodiment of the invention, one of two motor delays is selectively observed depending on how the user presents his hand(s) for drying. Referring now to the embodiment shown in schematic view in
For example, and in one preferred embodiment, if the first hand sensor 103 detects hand presentment to the hand-receiving cavity 52, the sensor 103a provides a corresponding electrical signal to the controller 78. The controller 78 includes software or firmware that distinguishes between an electrical signal being received from first sensor 103a versus the second, third, and fourth sensors 103b, 103c, 103d. With knowledge that the first object detection signal came from sensor 103a, the controller 78 provides hand dryer motor activation signal to the hand dryer controller 99. This motor activation signal results in the hand dryer motor being activated after a first programmed delay period, e.g., 0-300 ins. However, if any of the other sensors 103b, 103c, 103d provides a first detection signal to the controller 78, the hand dryer controller 99 causes operation of the hand dryer motor 74 after a second programmed delay period, e.g., 200-800 ms. The first and second delay periods are selected such that the second delay period preferably exceeds the first delay period. Thus, in one embodiment, operation of the hand dryer motor is delayed further if a user presents his hand(s) to the hand-receiving cavity 52 from the front. This allows more time for the user to move his hands deeper into the hand-receiving cavity 52 before the blower provides drying air to the hand-receiving cavity. Preferably, the drying airstreams are provided at approximately wrist level in the hand-receiving cavity 52, and observing a longer delay before commencing drying when hands are front-presented allows the user sufficient time to insert his hands to the wrist level position before air is injected into the cavity 52.
It is contemplated that more than one controller may be used to provide command signals to the hand dryer controller 99. For example, the first hand dryer sensor 103a may be coupled to a dedicated controller whereas the other sensors 103b, 103c, 103d communicate with a shared controller, similar to that shown in
In accordance with an alternate embodiment of the present invention, the hand dryer 50 may include a second bank or set of sensors. These sensors are mounted along a side portion of the upper plenum and are designed to sense side-presentment 267 of a user's hand(s) to the hand-receiving cavity. The afore-described sensors 103a, 103b, 103c, 103d are mounted adjacent the front of the hand-receiving cavity. Preferably, the respective sets of sensors have mutually exclusive FOV so that side-presentment from opening 65 of a user's hand(s) is not detected by the front-facing sensors and front-presentment from opening 64 of the user's hand(s) is not detected by the side-facing sensors.
Each set of sensors is operative to provide activation commands to the motor to commence operation of the motor. However, the front-facing sensors, upon detecting an object for drying 166 within their FOV, instruct the motor to commence activation after observing a longer second delay period than that provided to the motor by the side-sensing sensors. In one embodiment, the longer second delay period falls in the range of approximately 200-800 ms whereas the shorter first delay period falls in the range of approximately 0-300 ms. Note that these values are merely exemplary, and the first and second delay periods are preferably selected such that the second delay period exceeds the first delay period.
In accordance with yet another embodiment of the present invention, a single sensor is used to detect side or front presentment of a user's hand(s) from openings 65 and 64 respectively into the hand-receiving cavity 52. In this embodiment, which is shown in
In yet another embodiment that is similar to that described above with respect to
It will also be appreciated that the present invention can be embodied in a method of controlling the drying operation of a hand dryer 50 based on the position at which a user presents his hand(s) to a drying cavity or chamber 52 having at least two points of entry, for example, the side opening of drying chamber 65 and the front opening of drying chamber 64. (See, e.g.,
It will be appreciated that infrared sensors for detecting the ingress and egress of hands to and from the front of drying chamber 64 and the side of drying chamber 65 are but one of a number of different object-detecting technologies that could be used to detect an object for drying 166 in the drying chamber 52. For example, it is contemplated that camera and image processing technology could be used.
Further, it is contemplated that the invention could be used with a lavatory system having a single dryer situated between a pair of wash basins. It is also contemplated that sensors remote from the hand dryer 50 could determine the direction of presentment. For example, sensors at or near the water faucet could detect motion of the hands after the water faucet has stopped dispensing water. If the hands are pulled away from the faucet, the hand dryer 50 could be caused to operate with a front-presentment (e.g., along 268) to the hand-drying cavity assumed. If the hands are moved sideways from the faucet, a side-presentment (e.g., along 267) to the hand-drying cavity could be presumed.
It is also noted that so-called “smart” technology could be incorporated into the lavatory system described herein to guide or sequence use of the various components of the lavatory system. For example, the lavatory system could be equipped with directional lights that guide (or at least remind) the user to apply soap and, after washing, slide his hands into the drying chamber. Similarly, it is contemplated that the various components could be selectively locked out to prevent simultaneous activation of two components. For instance, it may be undesirable to have the water faucet capable of being activated when the dryer is forcing air into the drying cavity. If the water faucet was dispensing water while the dryer was active, it could lead to undesirable splashing of the water. Additionally, locking out certain components or features of the lavatory system may also sequence use of the lavatory system. For example, water faucet and dryer operations may be locked out until the soap dispenser has been activated. In such a situation, the aforementioned lights or similar devices could be used to direct the user to first apply soap to his hands before watering or drying his hands. Such a system may be highly preferred in food-handling operations, such as restaurants.
Referring again to
In one preferred method of use, one of four actions is taken based on the output of the filter sensor 272 and thus, preferably, the output of the filter sensor 272 is compared by the logic to potentially three different predefined levels. When the filter sensor 272 output is below a first vacuum level, as detected by the filter sensor 272, an indicator, e.g., light 278 (
thus, signals a user or maintenance personnel that the filter 84 must be replaced. An audible alarm may also sound. At a third vacuum level, as detected by the filter sensor 272, the motor controller 98 can shut down and disable operation of the motor 74 to prevent damage to the motor 74 or other components of the dryer. Maintenance personnel will then know to replace the filter. In addition, if a non filter related obstruction occurs in the air intake system upstream of the air filter sensor 272 (e.g., bathroom tissue plugging an inlet), and causes the output of the air filter sensor 272 to exceed a predetermined vacuum level, the air filter sensor 272 can trigger a service requirement, indicate a blocked inlet condition, and/or disable operation of the motor 74. Because the air filter sensor 272 detects the operating characteristics of the air flow within the motor air intake, the sensor provides feedback on the actual condition of the air filter. It will be appreciated that the invention actively monitors the operability of the filter rather than relying upon a predetermined number of cycles to indicate that a filter service is required.
In an alternate embodiment, a small tube (not shown) has an inlet end that is in fluid communication with the intake cavity 274 and an outlet end that is vented to atmosphere. In this embodiment, the filter sensor 272 is fluidly connected to the tube. In this embodiment, it will be appreciated that the filter sensor 272 remotely monitors the pressure (vacuum) in the intake cavity.
While the preferred embodiments and best modes of utilizing the present invention have been disclosed above, other variations are also possible. For example, the materials, shape, and size of the components may be changed. Additionally, it is understood that a number of modifications may be made in keeping with the spirit of the system 10 of the present invention. For example, the system 10 may include features of the various embodiments set forth in PCT Publication Nos. WO2007/083092 and WO2007/015045 to Dyson, and US Publication Nos. US2008/0109956A1 published on May 15, 2008 and 2006/0185074 published on Aug. 24, 2006, all of which are expressly incorporated herein by reference. Further, a number of lavatory systems like the one shown in
As described herein, a motor driven blower or fan is used to force air into the drying zone of the hand dryer. It is recognized that several types of motors may be used to drive operation of the blower or fan. For example, in one embodiment, the motor is a brushless motor having a nominal input of 120V at 60 Hz. It is understood that the motor could have other operating parameters and that the motor could be designed to be workable with various input voltages, i.e., 230V, such as that commonly found in Europe and Australia.
It is preferred that the brushless motor has a pulse width modulated speed control to switch the motor between ON and OFF. It is also preferred that the motor is thermally protected against over-heating, such as may result from a blocked inlet, locked rotor, or heightened ambient temperature.
The invention is not limited to a particular motor size but in one embodiment the motor provides 78 cfm of air at 2.8 psi. Preferably, the motor accelerates from zero rpm to operating speed in approximately 350 ms or less. It is also contemplated that different fan types (e.g., axial, bypass, centrifugal compressor, etc.) may be used. An axial or turbine (volute) type pump is also preferred but not required. It is preferred that the fan has either an axial or tangential discharge air flow. It is also preferred that heat from the motor is used to increase the temperature of the air fed to the drying chamber. In addition to heating the air, passing the air about the motor also provides thermal regulation of the motor.
Thus, it is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but includes modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 13/267429 | Oct 2011 | US | national |
The present application claims a benefit of priority under 35 USC §119 based on PCT/US2012/058678, filed on Oct. 4, 2012, which claims priority to U.S. patent application Ser. No. 13/267,429, filed Oct. 6, 2011, the disclosures of both which are expressly incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US12/58678 | 10/4/2012 | WO | 00 | 4/7/2014 |
