>FIG. 1, the one or more heating blowers 102 can be operably coupled to one or more second motors 114, which can be located external to the oven 100.

In one or more embodiments, the one or more heating blowers 102 can be in fluid communication with the one or more circulation blowers 110 (e.g., as shown in FIG. 1). For example, the one or more heating blowers 102 can heat air provided in the one or more circulation corridors 108 and/or supply the heated air to the one or more circulation blowers 110. The one or more circulation blowers 110 can then modulate circulation of the heated air in the one or more circulation corridors 108. For instance, the one or more circulation blowers 110 can moderate airflow in the one or more circulation corridors 108 that travels to the one or more processing chambers 106. At least because the one or more heating blowers 102 and the one or more circulation blowers 110 are powered by distinct motors (e.g., one or more first motors 112 and/or one or more second motors 114), the one or more heating blowers 102 can be operated independent of the one or more circulation blowers 110.

In one or more embodiments, the oven 100 can also comprise one or more sensors 116 located within the oven 100, such as a temperature sensor. For instance, the one or more sensors 116 can be located within the one or more processing chambers 106 (e.g., as shown in FIG. 1). Example sensors 116 can include, but are not limited to: a thermocouple, thermistor, a resistance temperature detector (RTD), a semiconductor-based temperature sensor, an infrared pyrometer, a combination thereof, and/or the like. The one or more sensors 116 can be operably coupled to one or more first controllers 118 via a direct electrical connection (e.g., as shown in FIG. 1) and/or a wireless network connection. For example, the one or more first controllers 118 can be digital first controllers 118 that can monitor the condition (such as the temperature of viscosity) of the air within the processing chamber 106 (e.g., via the one or more sensors 116). Alternatively or additionally, the one or more first controllers 118 can monitor the condition of the air within the one or more circulation corridors 108. A user of the oven 100 can utilize the one or more first controllers 118 to observe the air condition within the one or more processing chambers 106 and/or set changes to said condition (e.g., increase or decrease the air temperature within the one or more processing chambers 106). In one or more embodiments, the one or more first controllers 118 can be operably coupled to a plurality of sensors 116 located in various positions within the one or more processing chambers 106 to monitor air temperature uniformity within the one or more processing chambers 106. Example first controllers 118 can comprise, but are not limited to: analog controllers, digital proportional integral derivative (PID) controllers, programmable logic controllers, computer software, a combination thereof, and/or the like.

The one or more first controllers 118 can be further coupled to one or more second controllers 120 via a direct electrical connection (e.g., as shown in FIG. 1) and/or a wireless network connection. Further, the one or more second controllers 120 can be operably coupled to the one or more second motors 114 via a direct electrical connection (e.g., as shown in FIG. 1) and/or a wireless network connection. For example, the one or more second controllers 120 can be an alternating current (“AC”) variable frequency drive (“VFD”), which can enable the speed (i.e., revolutions per minute (“RPM”)) of the one or more second motors 114 to be varied over a wide range. Example of second controllers 120 can include, but are not limited to: variable frequency drive (VFD), a Pulse Width Modulated (PWM) AC speed control, a PWM DC speed control, a Silicon Controlled Rectifier (SCR) AC speed control, an SCR DC speed control, a variable voltage AC supply, a variable voltage DC supply, a variable current AC supply, a variable current DC supply, a thyristor based AC motor speed control, a thyristor based DC motor speed control, or a single-phase AC motor controller that uses Phase Angle Control, mechanical speed controls, a combination thereof, and/or the like. Additionally or alternatively, the second controller may limit or adjust output power to the one or more second motors 114 using a regulated power supply that incorporates a constant current limiting circuit, a fold-back current limiting circuit, or other type of output power limiting. Additionally or alternatively, the second controller may monitor and/or adjust the input power to the heating blower 102 using a continuously variable transmission or clutch operably coupled between the second motor 114 and the heating blower 102.

The one or more first controllers 118 can generate a signal output based on the monitored condition (e.g., air temperature) within the one or more processing chambers 106 (which the first controller 118 receives as feedback) and/or one or more user inputs supplied to the one or more first controllers 118. The output signal may additionally or alternatively be based on other feedback, such as current draw experienced by the second motor, power input to the second motor 114, torque output of the second motor 114, rotational speed of the heating blower 102, and/or a frequency output sent from the second controller 120 to the second motor 102. The inputs may include, for example, properties of the air within the one or more processing chambers 106 and the one or more circulation corridors 108. The properties may be related to those that affect fluid flow, such as viscosity or density of the air. The inputs may further include how these properties, with respect to a particular air formulation, are altered with a change in temperature. Additionally or alternatively, some or all of these inputs may be automatically retrieved from a database that electronically stores these properties and is in electronic communication with the first controller 118. It will be appreciated that the output signal of the first controller 118 may be a combination of outputs from, for example, a PID control loop and an algorithm. The algorithm may alter the output of the PID control loop in generating its own output.

In an embodiment, in generating a signal output, and sending it to the second controller 120, the first controller 118 may utilize an algorithm in its system software, wherein the output of the algorithm is a function of the temperature of the air within a process chamber 106 (the “process temperature”) or circulation corridor 108. It will be appreciated that the output signal of the first controller 118 may a combination of outputs from, for example, PID control loop and an algorithm. Additionally or alternatively, the output of the algorithm may be a function of current draw of the second motor, power input to the second motor 114, torque output of the second motor 114, rotational speed of the heating blower 102, and/or a frequency output sent from the second controller 120 to the second motor 102. Additionally or alternatively, the output of the algorithm may be a function of one or more inputs, such as the air's density or viscosity (as either change within a range of temperatures), or other properties of the fluid. In an embodiment, output of the algorithm (and thus, the output of the first controller 118) may result in a linear increase in rotational speed of the second motor 114 as the process temperature increases from an initial to a set temperature, allowing the second motor 114 to experience a current draw substantially near its maximum while the process temperature increases to the set temperature.

The output signal of the first controller 118 can be sent to the one or more second controllers 120, which can then modulate operation of the one or more second motors 114, and thereby the one or more heating blowers 102, based on the signal (e.g., an electrical signal). For instance, the one or more second controllers 120 can control operation of the one or more second motors 114 to vary the maximum rotational speed of one or more impellers comprised within the one or more heating blowers 102; thereby modulating the amount of heat generated by the one or more heating blowers 102. Thus, the one or more second controllers 120 can modulate the temperature (or other condition) within the one or more processing chambers 106 by varying the operation of the one or more heating blowers 102 (e.g., via the one or more second motors 114) based on one or more signals (e.g., commands) generated by the one or more first controllers 118. In an embodiment, the maximum rotational speed of the heating blower 102 may be automatically adjusted or limited by using a continuously variable transmission, clutch, or a mechanical adjustable speed drive between the second motor 114 and the heating blower 102.

In an embodiment of a friction heated oven system, the first controller 118 has a proportional-integral-derivation (PID) controller, and the second controller 120 has a variable frequency drive (VFD) that controls the second controller's output frequency to the second motor 114. The algorithm is used to adjust the PID loop output signal of the first controller 112 before it is sent to the second controller 120. For example, the algorithm may produce an output (an “algorithmic output”) which varies between 0.75 and 1.00 for process temperatures between an initial temperature and a set temperature. The PID loop output signal is multiplied by algorithmic output, and the resulting product is sent from the first controller to the second controller as an analog signal to control the maximum rotational motor speed. In an embodiment, the second controller is set to operate the second motor at a maximum speed at 80 Hz—a maximum motor frequency. This speed is selected to prevent overloading of the motor at the set temperature. At the initial temperature, the output of the second controller may be 60 Hz (based on the algorithmic output)—a first motor frequency. This speed is selected to prevent overloading of the second motor at the initial temperature. The effect of this arrangement is that when the temperature is gradually increased from the initial temperature to the set temperature, the motor frequency of the second motor is gradually increased from the first motor frequency to the maximum motor frequency. This gradual increase in motor frequency sent from the second controller and received by the second motor allows the second motor to experience a current draw substantially near its maximum for all temperatures between and including the initial temperature and the set temperature. The same principle applies to other conditions, such as viscosity of the air. This allows process chambers 106 within friction heated ovens 100 to reach higher temperatures and reach them in shorter periods of time. Without the adjustment provided by the algorithmic adjustment, as the temperature increases and the air becomes less dense, the motor torque will drop off rapidly, the motor will do less work and its experienced current draw will be less.

In another embodiment of a friction heated oven system, a signal generated by a first controller 118 and sent to a second controller 120 controlling the second motor 114 varies based on the monitored (or process) temperature within a processing chamber 116. In this embodiment, the monitored temperature is substantially equal to or between an ambient (or initial) temperature and a final (or set) temperature, which is the process temperature the user of the oven would like the oven to be maintained at for a period of time. The temperatures between and including the initial and set temperatures may be known as the range of temperatures. At the initial temperature, as measured by a sensor 116, the first controller 118 sends a first signal to the second controller 120 allowing the second motor 114 to operate at a first maximum rotational speed. At a second temperature greater than the first temperature, the first controller 118 sends a second signal to the second controller 120 allowing the second motor 114 to operate at a second maximum rotational speed that is greater than the first speed. This may be repeated automatically (i.e., without user intervention) until the process temperature is substantially equal to the set temperature, at which point the signal from the first controller to the second controller commands the motor to operate at a speed such that the process temperature is maintained at or substantially near the set temperature for a period of time. Where (n) is the number of temperatures between and including the initial and final temperatures, there may be (n) number of distinct signals the first controller 118 can send the second controller, resulting in (n) number of distinct maximum rotational speeds of the second motor. The maximum rotational motor speeds of the second motor, such as the first and second and (n)th speeds, are chosen so as to maintain the maximum output power of the second motor (as rated by its manufacturer) throughout the entire range of temperatures between and including the initial and set temperature, but not to exceed the rated output power of the second motor. Alternatively or additionally, the motor speeds of the second motor, such as the first and second and (n)th speeds, are chosen so as to have the second motor experience its maximum rated current draw throughout the entire range of temperatures between and including the initial and set temperature.

For example, the initial temperature may be 70 degrees F. and the set temperature may be 700 degrees F. As the process temperature rises from 70 degrees F. to 700 degrees F., the maximum rotational motor speed of the second motor 114 may start out at 3600 RPM and be slowly increased to 4800 RPM, as the first controller 114 (via an algorithm, as discussed above) compensates for the increase in process temperature, and accordingly, a decrease in fluid density. Increasing the maximum rotational speed of the second motor 114 as the process temperature increases allows the process chamber 114 to reach significantly higher process temperatures and to reach them in a shorter period of time than systems where the maximum rotational speed of the second motor 114 is not increased in accordance with an increase in process temperature. Increasing the maximum rotational speed of the second motor 114 as the process temperature increases allows for maximum power output and experience current draw of the second motor throughout the range of temperatures without it overloading.

In an embodiment, at an initial or first temperature, the first controller 118 sends a first signal to the second controller 120 allowing the second motor 114 to operate at a first maximum rotational speed. At the first speed, the second motor 114 is operating substantially near its maximum rated current draw. At a second temperature greater than the first temperature, where the second motor 114 is not operating substantially near its maximum rated current draw, the speed of the motor 114 may be manually increased by a user, for example, by selecting one of several speeds on a multi-speed electric motor, such that the second motor speed 114 is increased from a first speed to a second speed greater than the first speed, wherein the second motor 114 operating at the second speed is operating substantially near its maximum rated current draw. These steps may be repeated until the process temperature of the air reaches the set temperature.

In an embodiment, the first controller 118 monitors the current draw experienced by the second motor 114. The first controller 118 may monitor the current draw via feedback from the second controller 120 or a separate sensor, such as a current transducer. Additionally, the first controller 118 receives, for example, from an electronically connected database or from user input, a maximum rating of the second motor's current draw. For example, if the second motor's 114 experienced current draw is below its maximum rating, the first controller 118 may send a signal to the second controller 120 commanding the second controller 120 to increase the frequency to the second motor 114, and thus, the rotational speed, of the motor 114 until the second motor's 114 experienced current draw is substantially near its maximum rating. Further, if the second motor's current draw is exceeding its maximum rating, the first controller 118 may send a signal to the second controller 120 commanding the second controller 120 to decrease the frequency of the motor until the second motor's 114 experienced current draw is substantially near its maximum rating.

In an embodiment, the first controller 118 may monitor the power consumption of the second motor 114. The first controller 118 may monitor the power consumption via feedback from the second controller or a separate sensor. Additionally, the first controller 118 receives, for example, from an electronically connected database or from user input, a maximum rating of the power consumption of the second motor 114. For example, if the second motor's 114 power consumption is below its maximum rating, the first controller may send a signal to the second controller 120 commanding the second controller 120 to increase the frequency, and thus, the speed, of the motor 114 until the second motor's 114 power consumption is substantially near its maximum rating. Further, if the second motor's 114 power consumption is exceeding its maximum rating, the first controller 118 may send a signal to the second controller 120 commanding the second controller 120 to decrease the frequency of the motor 114 until the second motor's 114 power consumption is substantially near its maximum rating.

In an embodiment, the first controller 118 may monitor the torque output of the second motor 114. The first controller 118 may monitor the torque output via feedback from the second controller 120, the second motor 114, or a separate sensor. Additionally, the first controller 118 may receive, for example, from an electronically connected database or from user input, a maximum torque rating of the second motor 114. In an embodiment, if the second motor's 114 torque output is below its maximum rating, the first controller 118 may send a signal to the second controller 120 commanding the second controller 120 to increase the frequency, and thus, the speed, of the motor 114 until the second motor's 114 torque output is substantially near its maximum rating. Further, if the second motor's 114 torque output is exceeding its maximum rating, the first controller 118 may send a signal to the second controller 120 commanding the second controller 120 to decrease the frequency of the motor 114 until the second motor's 114 torque output is substantially near its maximum rating.

Moreover, operation of the one or more heating blowers 102 can be controlled (e.g., by the one or more second controllers 120) independent of the one or more circulation blowers 110. Thereby the amount of heat generated by the oven 100 (e.g., via fan friction of the one or more heating blowers 102 instead of, or supplement to, conventional heating elements) can be adjusted independent of the airflow established by the one or more circulation blowers 110. For example, the amount of heat generated by the one or more heating blowers 102 can vary based on the temperature conditions within the one or more processing chambers 106 (e.g., as monitored by the one or more temperature sensors 116), while the airflow within the oven 100 can remain constant.

In one or more embodiments, one or more conventional heat sources can be present within and/or adjacent to the oven 100 in addition to the one or more heating blowers 102 and/or circulation blowers 110. For example, the one or more conventional heat sources can provide supplemental heat to the heat generated by the one or more heating blowers 102, which can enable embodiments of the oven 100 comprising heating blowers 102 of various size and/or power. The conventional heat sources can have a fixed power output or can be adjustable and/or modulated. Additionally, the type of circulation blowers 110 included in the oven 100 can be selected based on a desired base temperature range of the oven 100. In one or more embodiments, one or more of the heating blowers 102 can operate at a fixed speed to establish a base heating temperature, wherein one or more other heating blowers 102 can operate at adjustable speeds to modulate the working temperature within the one or more processing chambers 106.

FIG. 2 illustrates an example, non-limiting diagram of the oven 100, wherein the one or more circulation corridors 108 can extend further around the one or more processing chambers 106. Repetitive description of like elements employed in other embodiments described herein is omitted for sake of brevity. FIG. 2 exemplifies that the one or more circulation corridors 108 can be positioned in a variety of arrangements to facilitate the heating of one or more processing chambers 106 via one or more airflow configurations (e.g., driven by the one or more circulation blowers 110).

As shown in FIG. 2, the one or more circulation corridors 108 can surround the entire, or substantially the entire, perimeter of the one or more processing chambers 106. For example, air heated by the one or more heating blowers 102 can be circulated around and/or adjacent to the one or more processing chambers 106 by the one or more circulation blowers 110 (e.g., as shown in FIG. 2). Heated air flowing adjacent to the one or more processing chambers 106 can in turn heat the one or more processing chambers 106 (e.g., at least because of the heated air's proximity to the one or more processing chambers 106). In another example, various airflow configurations within the one or more processing chambers 106 can be facilitated by supplying heated air to various sides of the one or more processing chambers 106 via the one or more circulation corridors 108 extending around the one or more processing chambers 106. For instance, three of the walls defining a processing chamber 106 can be perforated to facilitate horizontal and/or vertical airflow configurations.

FIG. 3 illustrates an example, non-limiting diagram of the oven 100 further comprising one or more intake ports 302 and/or one or more exhaust ports 304 in accordance with one or more embodiments described herein. Repetitive description of like elements employed in other embodiments described herein is omitted for sake of brevity. As shown in FIG. 3, the one or more intake ports 302 and/or the one or more exhaust ports 304 can be in fluid communication with the one or more circulation corridors 108 through the one or more exterior walls 104 of the oven 100.

In one or more embodiments, the intake port 302 and/or the exhaust port 304 can be utilized by the oven 100 to draw external air into the oven 100 and/or expel processed air out of the oven 100. By cycling fresh air into the airflow within the oven 100 and/or expelling processed air out of the oven 100, vapors resulting from heating one or more items within the one or more processing chambers 106 can be expelled from the one or more processing chambers 106 before becoming hazardous.

For example, in one or more embodiments air heated by the one or more heating blowers 102 can be fresh air introduced into the oven 100 via the one or more air intake ports 302. For instance, the fresh air can be isolated from the processed air (e.g., air previously heated and/or introduced into the one or more processing chambers 106) such that the one or more heating blowers 102 heat fresh air and can avoid heating processed air, which can comprise one or more contaminates originating from the heating in the one or more processing chambers 106.

The one or more circulation blowers 110 can then circulate the heated fresh air through the oven 100 (e.g., into the one or more processing chambers 106) while the processed air (e.g., air already used to heat one or more items within the one or more processing chambers 106) can be expelled from the oven 100 via the one or more exhaust ports 304.

In another example, in one or more embodiments the one or more heating blowers 102 can heat fresh air (e.g., supplied by the one or more air intake ports 302) and/or processed air (e.g., previously heated air driven to the one or more heating blowers 102 by an airflow generated by the one or more circulation blowers 110) in combination. In other words, the fresh air can be mixed with processed air within the oven 100 during the heating achieved by the one or more heating blowers 102.

In one or more embodiments, the oven 100 can comprise various configurations of the one or more intake ports 302 and/or exhaust ports 304. For example, the oven 100 can lack the one or more input ports 302 and/or exhaust ports 304 (e.g., as shown in FIG. 1). In another example, the oven 100 can comprise one or more input ports 302 and/or one or more exhaust ports 304. In a further example, the oven 100 can comprise one or more input ports 302 operably coupled to one or more intake blowers (not shown) and/or one or more exhaust ports 304 operably coupled to one or more exhaust blowers 306 (e.g., as shown in FIG. 3).

One of ordinary skill in the art will recognize that the architecture of the one or more circulation corridors 108 can vary to facilitate embodiments in which fresh air is isolated or mixed with processed air during the heating by the one or more heating blowers 102. Whether the fresh air is isolated or mixed with the processed air can depend on the function of the oven 100 and/or the items being heating within the one or more processing chambers 106.

FIG. 4 illustrates a diagram of the example, non-limiting oven 100 comprising the one or more air intake ports 302 and/or exhaust ports 304 (e.g., including one or more exhaust blowers 306) in accordance with one or more embodiments described herein. Repetitive description of like elements employed in other embodiments described herein is omitted for sake of brevity. FIG. 4 exemplifies that the oven 100 can be configured with one or more air intake ports 302 and/or one or more exhaust ports 304 with various circulation corridor 108 arrangements.

FIG. 5 illustrates a diagram of the example, non-limiting oven 100, wherein the second controller 120 can be operably coupled to both the first motor 112 and/or the second motor 114 in accordance with one or more embodiments described herein. Repetitive description of like elements employed in other embodiments described herein is omitted for sake of brevity. For example, the second controller 120 can control operation of both the one or more heating blowers 102 and/or the one or more circulation blowers 110 (e.g., via the one or more second motors 114 and/or the one or more first motors 112) independent of each other.

Further, the oven 100 can comprise one or more airflow sensors 502 positioned in the one or more circulation corridors 108 (e.g., as shown in FIG. 5) and/or in the one or more processing chambers 106. The one or more airflow sensors 502 can be operably coupled (e.g., via a direct electrical connection and/or via a wireless network connection) to the one or more second controllers 120. Also, the one or more airflow sensors 502 can monitor one or more properties of the airflow generated by the one or more circulation blowers 110 at one or more locations within the oven 100. Example properties that can be monitored by the one or more airflow sensors 502 can include, but are not limited to: air velocity, humidity, air composition (e.g., the presence of one or more hazardous vapors), air temperature, oxygen concentration, dewpoint, a combination thereof, and/or the like. For instance, one or more of the airflow sensors 502 can comprise anemometers to facilitate monitoring air velocity.

In one or more embodiments, the second controller 120 can control operation of the one or more circulation blowers 110 based on one or more airflow properties monitored by the one or more airflow sensors 502. For example, the second controller 120 can increase the RPMs of the one or more first motors 112 in order to increase the amount of airflow generated by the one or more circulation blowers 110 based on an amount of hazardous vapors detected by the one or more airflow sensors 502. Thereby, the oven 100 can mitigate potential damages that can be caused by the buildup of hazardous vapors as a result of the heating in the one or more processing chambers 106. As described herein, the second controller 120 can modulate the heating generated by the one or more heating blowers 102 independent of the airflow generated by the one or more circulation blowers 110. Alternatively, in one or more embodiments, the one or more first motors 112 can be controlled by a one second controller 120 while the one or more second motors 114 can be controlled by another second controller