The present disclosure relates to air flow pressure compensator systems incorporated into clothes dryers to increase air flow and improve clothes drying efficiency.
Multiple factors affect the drying efficiency of clothes dryers and particularly how air flows through a dryer. These factors include, but are not limited to, the positioning and arrangement of exhaust ducting and the blockage of air exiting the tumbler.
When a clothes dryer system is installed, exhaust ducting is coupled to the system and then positioned and arranged to a vent the dryer to the outside. However, frequently during installation, exhaust ducting is particularly lengthy due to the long distance between the outer dryer vent and outside venting. Depending on where the installation is placed, exhaust ducting may also be arranged to have a large number of twists and turns in order reach outside venting. What results from arranging exhaust ducting in this manner is a ducting environment that affects the overall efficiency of the clothes dryer. For example, high static pressure will likely develop within in the exhaust ducting, reducing air flow in system and extending drying times for clothes.
Also, as a cycle of a clothes dryer progresses, the removal of moisture from clothing causes clothes to impede air flow in the system. As clothes dry, the nature of clothing materials change. Some materials tend to fan or spread out and block air from exiting the tumbler. This reduces air flow through the clothing material and also negatively affects drying times.
For these reasons, among others, there is a clear need for air flow pressure compensator systems incorporated into clothes dryers to increase air flow and improve clothes drying efficiency. The present invention fulfills this need and provides further related advantages, as described below.
Disclosed herein is an air flow pressure compensator system used to maintain substantially constants air flow within a clothes dryer system. Specifically, the compensator system adjusts the speed of one or more exhaust fans by monitoring one or more sensors/transmitters positioned in one or more exhaust ducts and/or one or more incoming air ducts. Real-time monitoring of the sensors/transmitters allow for system adjustments which improve clothing drying time and dryer efficiency. These adjustments, therefore, compensate for inefficiencies in the clothes dryer and enhance overall dryer performance.
A more complete understanding of the air flow pressure compensator system will be afforded to those skilled in the art, as well as a realization of additional advantages and objects thereof, by consideration of the following detailed description. Reference will be made to the appended sheets of the drawings, which will first be described briefly.
The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
In the drawings:
Turning in detail to the drawings,
As shown in
The id-series dryer models sold by American Dryer Corporation also incorporate features that complement the air flow pressure compensator system 10. As illustrated particularly in
Another feature incorporated into the id-series is ADC's patented SENSOR ACTIVATED FIRE EXTINGUISHING (S.A.F.E)™ system, as described in U.S. Pat. Nos. 5,197,203, 6,505,418, and 6,725,570, which are incorporated herein by reference. Some models, which incorporate the air flow pressure compensator systems, include the id35, id50, id80, id120, id30x2, and id45x2 models. Other dryers and dryer systems, however, may incorporate the air flow pressure compensator systems disclosed herein.
Programming controls 24 (
Referring back to
The anemometers or differential pressure sensor/transmitters 18 are used in the system 10 to measure pressure and convert the pressure to an electrical signal (I.E. 0-10 volt, 4-20 ma, serial data, and/or another means of transferring a measured output). Output signals 26 are then interpreted by the compensator controller 12 and/or the variable frequency drive (VFD) to increase or decrease fan speed such that substantially constant airflow is maintained during dryer operation. As airflow is impeded, as indicated by measurements taken at V1, V2 and/or V3, fan speed will be increased or decreased to maintain substantially constant airflow. Airflow velocity will generally range from 0 to 1 inch water column.
Suitable sensors/transmitters for use in the system include MAGNESENSE® Differential Pressure Transmitters sold by Dwyer Instruments Inc. In a preferred configuration, specifications for the variable frequency drive include the following:
Accuracy: ±1% for 0.25″ (50 Pa), 0.5″ (100 Pa), 2″ (500 Pa), 5″ (1250 Pa), 10″ (2 kPa), 15″ (3 kPa), 25″ (5 kPa) 12% for 0.1″ (25 Pa), 1″ (250 Pa) and all bidirectional ranges.
Electrical Entry: ½″ NPS Thread. Accessory: Cable Gland for 5 to 10 mm diameter cable.
The sensors/transmitters may be connected directly to the variable frequency drive or connected directly to a microcontroller. When a sensor is connected directly to the variable frequency drive, a control decision point is made in the variable frequency drive. When a sensor/transmitter is connected directly to the microcontroller, the control decision point is made in the controller. Decision points are determined by the differential pressure sensor in conjunction with the variable speed drive (VFD). As the sensor detects changes in pressure between 0 and 1 in of WC (Water Column), one or more sensors/transmitters will output a signal between 4 and 20 ma, where 4 ma corresponds to 0 inches WC and 20 ma corresponds to 1 in WC. The variable frequency drive then will use the 4 to 20 ma signal from the sensors/transmitters to change the frequency of the motor and either increase or decrease the fan speed, thereby increasing or decreasing airflow. The variable frequency drive uses a percentage of the 4 to 20 MA, where 4 ma is 0% and 20 ma is 100% to make the adjustment(s).
An alternative method of adjusting fan speed without sensors is to monitor fan motor current. As static pressure increases, fan motor current decreases as the fan pushes less air. Conversely, as static pressure decreases, fan motor current increases as the fan pushes more air.
Using the variable frequency drive to control the fan motor and using fan motor current, particularly symmetrical fan motor current limits function of the variable frequency drive such that one can control the speed of the fan by (1) setting a maximum symmetrical current to a desired percentage of maximum fan motor current, where the maximum symmetrical current will allow the fan motor to run at its maximum current based on a predetermined percentage parameter. Setting a thermal protection parameter to “on” and presetting the variable frequency drive to a maximum desired frequency. When using this control method, as the static pressure increases and the current begin to drop, the variable frequency drive increases the frequency to the motor, and thereby increase motor fan speed until the maximum predetermined percentage parameter has been, thus stabilizing the fan speed.
Conversely, as the static pressure decreases and the motor current begins to rise, the variable frequency drive decreases motor frequency, thereby slowing motor fan speed until the frequency is lowered such that motor current is below a maximum symmetrical current percentage of the motor current. This method also provides a real time fan response, which corresponds to different levels of static pressure.
The following examples were performed on an ADC Intelligent Dryer Model id120 to assess dryer performance at varying exhaust fan frequencies. Static pressures were set to either 0.6″ w.c. or 1.5″ w.c. @ 60 Hz while the dryer was empty.
The disclosure has been illustrated by detailed description and examples of particular embodiments. Various changes in form and detail may be made to the illustrative embodiments without departing from the spirit and scope of the present invention. It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that the present invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
This application claims priority to International Application No. PCT/US2014/047363, filed Jul. 21, 2014, which claims priority to U.S. Application Ser. No. 61/856,259, filed Jul. 19, 2013, the entirety of which is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/US2014/047363 | 7/21/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2015/010115 | 1/22/2015 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
4081997 | Losert | Apr 1978 | A |
6725732 | Stein | Apr 2004 | B1 |
6745495 | Riddle et al. | Jun 2004 | B1 |
6829522 | Filev et al. | Dec 2004 | B1 |
7870799 | Neumann | Jan 2011 | B2 |
20030030408 | Ratz et al. | Feb 2003 | A1 |
20100045472 | Siddall | Feb 2010 | A1 |
20100256821 | Jeung et al. | Oct 2010 | A1 |
20110290043 | Lehman | Dec 2011 | A1 |
Number | Date | Country |
---|---|---|
102008049034 | Apr 2010 | DE |
1775368 | Apr 2007 | EP |
2072910 | Jun 2009 | EP |
2008058211 | May 2008 | WO |
Entry |
---|
European Search Report for Counterpart EP14826584.6, dated Nov. 23, 2016. |
International Search Report and Written Opinion for Counterpart PCT/US2014/047363, dated Nov. 3, 2014. |
Number | Date | Country | |
---|---|---|---|
20160244907 A1 | Aug 2016 | US |
Number | Date | Country | |
---|---|---|---|
61856259 | Jul 2013 | US |