Patent Application
20110302942
The present invention relates to transporting temperature sensitive goods. Specifically, the invention relates to temperature and environmental controls for a transport refrigeration unit.
In one embodiment, the invention provides an environment control unit for controlling the environment of a cargo space of a transport container. The environment control unit includes a housing that is configured to be coupled to the transport container. An environment control system is positioned within the housing to adjust the temperature of air within the cargo space. A Reactive Oxygen Species (ROS) generator is positioned within the housing to generate reactive oxygen species in the air within the cargo space. A controller is positioned within the housing and is in electrical communication with the environmental control system and the ROS generator. The controller operates the environment control system to selectively adjust the temperature of the air within the cargo space and operates the ROS generator to selectively generate the reactive oxygen species into the air within the cargo space. Operation of the ROS generator is based on at least one operating condition of the environment control system.
In another embodiment, the invention provides an environment control unit for a transport container including a cargo space. The environment control unit includes a housing that is mounted to the transport container and defines an air return and an air supply. An environment control system is positioned within the housing at least partially between the air return and the air supply, and adjusts a temperature within the cargo space. An ROS generator is positioned within the housing and provides reactive oxygen species to the cargo space. A temperature sensor is positioned to detect a temperature indicative of the temperature within the cargo space and a reactive oxygen species sensor is positioned to detect a concentration of reactive oxygen species indicative of a concentration of reactive oxygen species within the cargo space. A controller is positioned within the housing and is in communication with the environment control system, the ROS generator, the temperature sensor, and the reactive oxygen species sensor. The controller is operable to control the environment control system and the ROS generator based at least in part on information received from the temperature sensor and the reactive oxygen species generator. A human-machine interface (HMI) is in communication with the controller and is manipulatable by a user to produce the desired environmental condition.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways
The trailer 14 includes a frame 28 with walls 30, a floor 32, a roof 34, and rear access doors 36 attached thereto. A plurality of wheels 24 are rotatably attached to the frame 28 for movement over the ground. A coupling portion 38 is configured to couple to the tractor 12 so the trailer 14 may be pulled. The walls 30, floor 32, roof 34, and rear access doors 36 define a cargo space 40 on the interior of the trailer 14. The trailer 14 is one type of transport container. In other embodiments, the transport container could be a shipping container, a cargo container on a straight truck, a rail container, an air shipping container, or the like.
An environment control unit 42 is attached to the wall of the trailer 14. Turning to
A discharge valve 134 and a discharge line 136 connect the compressor 122 to a three-way valve 138. A discharge pressure transducer 140 is located along the discharge line 136, upstream from the three-way valve 138 to measure the discharge pressure of the compressed refrigerant. The three-way valve 138 includes a first outlet port 142 and a second outlet port 144.
When the environment control unit 42 is operated in a COOLING mode, the three-way valve 138 is adjusted to direct refrigerant from the compressor 122 through the first outlet port 142 and along a first circuit or flow path (represented by arrows 148). When the environment control unit 42 is operated in either a HEATING mode or a DEFROST mode, the three-way valve 138 is adjusted to direct refrigerant through the second outlet port 144 and along a second circuit or flow path (represented by arrows 150).
The first flow path 148 extends from the compressor 122 through the first outlet port 142 of the three-way valve 138, a condenser coil 152, a one-way condenser check valve 153, a receiver 156, a liquid line 158, a refrigerant drier 160, a heat exchanger 162, an expansion valve 164, a refrigerant distributor 166, an evaporator coil 168, an electronic throttling valve 170, a suction pressure transducer 172, a second path 174 through the heat exchanger 162, an accumulator 176, a suction line 178, and back to the compressor 122 through a suction port 180. The expansion valve 164 is controlled by a thermal bulb 182 and an equalizer line 184.
The second flow path 150 can bypass a section of the refrigeration circuit, including the condenser coil 152 and the expansion valve 164, and can connect the hot gas output of compressor 122 to the refrigerant distributor 166 via a hot gas line 188 and a defrost pan heater 190. The second flow path 150 continues from the refrigerant distributor 166 through the evaporator coil 168, the throttling valve 170, the suction pressure transducer 172, the second path 174 through the heat exchanger 162, and the accumulator 176 and back to the compressor 122 via the suction line 178 and the suction port 180.
A hot gas bypass valve 192 is disposed to inject hot gas into the hot gas line 188 during operation in the COOLING mode. A bypass or pressurizing line 196 connects the hot gas line 188 to the receiver 156 via check valves 194 to force refrigerant from the receiver 156 into the second flow path 150 during operation in either the HEATING MODE or the DEFROST mode.
Line 100 connects the three-way valve 138 to the low-pressure side of the compressor 122 via a normally closed pilot valve 198. When the valve 198 is closed, the three-way valve 138 is biased (e.g., spring biased) to select the first outlet port 142 of the three-way valve 138. When the evaporator coil 152 requires defrosting and when heating is required, valve 192 is energized and the low pressure side of the compressor 122 operates the three-way valve 138 to select the second outlet port 144 to begin operation in the HEATING mode and/or DEFROST modes.
A condenser fan or blower (i.e., an air moving device) directs ambient air across the condenser coil 152. Return air heated by contact with the condenser coil 152 is discharged to the atmosphere. An air moving device in the form of an evaporator fan 200 draws return air (represented by arrows 202) through an inlet 204. A return air temperature sensor 206 measures the temperature of air entering the inlet 204. An evaporator coil temperature sensor can be positioned adjacent to or on the evaporator coil 168 for recording the evaporator coil temperature. In other embodiments, the evaporator coil temperature sensor can be positioned in other locations. In still other embodiments, other sensors such as a discharge air temperature sensor can also or alternately be used. The fans can be directly coupled to the engine 126 for rotation or alternatively, they can be driven by electric motors.
Discharge air (represented by arrow 208) is returned to the cargo space 40 via outlet 210. Basically, when operating in the COOLING mode the environment control unit 42 cools the air within the housing 44 prior to being discharged into the cargo space 40 and when operating in the HEATING mode where the environment control unit 42 heats the air within the housing 44 prior to being discharged into the cargo space 40. During the DEFROST mode, a damper 212 is moved from an opened position (shown in
A reaction unit 316 or reactive oxygen species generator (ROS generator) is disposed between the inlet 204 and the outlet 210. The reaction unit 316 generates reactive oxygen species from oxygen (O2) in the air received through the inlet 204. For example, a suitable reaction unit is described in U.S. Patent Publication No. 2007/0119699 (U.S. application Ser. No. 11/289,363) filed Nov. 30, 2005, the contents of which are incorporated herein in their entirety. The illustrated reaction unit 316 is shown downstream of the evaporator coil 168. In other constructions, the reaction unit 316 could be positioned upstream of the evaporator coil 168 or anywhere within the housing, as desired.
The introduction of air into the reaction unit 316 may be mediated through a forced suction or by natural suction. Preferably, the air is drawn through a filter to remove dust and other macroscopic impurities that may be present in the air to be sanitized before the air enters the reaction unit 316.
Preferably, the reaction chambers 300 are held in place within the array by a coupler arranged on both ends of the reaction chambers 300. The coupler may include a clamp 303 for securing the reaction chambers 300 in a desired location within the array. A center support rod 312 may be included in the array and appropriately secured by the clamp 303 to provide additional structural integrity to the array. The coupler may further include an electrically conductive contact 304, 305 cooperatively shaped with the clamp 303 and contacting each of the reaction chambers 300 within the array. The contact 304 may be integrally formed with the clamp 303 or mechanically attached to the clamp 303 by an adhesive or mechanical fasteners 311.
The coupler preferably cooperates with an inner surface of the reaction unit housing 302 to secure the reaction chambers 300 within the reaction unit housing 302. The array may be fixed within the reaction unit housing 302 using contact studs 309. The electrically conductive contact studs 309 pass through the reaction unit housing 302 and interact with the coupler so as to fixedly secure the clamp 303 in relation to the reaction unit housing 302 and electrically connect with the contacts 304, 305. In this manner, the necessary electrical connections between the reaction chamber 300 of the reaction unit 316 and the prime mover (or a generator powered by the prime mover) may be achieved through the contact studs 309. However, one of ordinary skill in the art will recognize that the necessary electrical connections may be achieved by multiple means.
As shown in
The reaction unit 316 splits the oxygen in the air into large amounts of reactive oxygen species. The reactive oxygen species generated may include singlet oxygen (1O2), ozone (O2), atomic oxygen (O), superoxide (O2—), hydrogen peroxide (H2O2), hydroxyl radical (OH—), and peroxynitrite (ONOO—). Even though many reactive oxygen species have a short half-life, they are effective sanitizing agents. Thus, as the air passes through the reaction unit 316, a large percentage of the airborne contaminants in the air are neutralized by the generated reactive oxygen species before the air is exhausted through the outlet 210. Additionally, the reactive oxygen species are carried into the cargo space 40 where they sanitize products and surfaces in the cargo space 40. In this manner, the reactive oxygen species generated in the reaction unit 316 act as a sanitizer.
One of the reactive oxygen species generated by the reaction unit 316 is ozone (O3). The generated ozone is introduced into the air in the reaction unit 316, and the ozone also acts as a sanitizer of the air and environment. The ozone generated in the reaction unit 316 may be discharged with the air through the outlet 210. The ozone in the discharged air provides the beneficial preservative effects and acts as a sanitizer for any surfaces in the environment into which the air is discharged. Other reactive oxygen species, such as hydrogen peroxide, may also be discharged with the sanitized air and have sanitizing effects similar to ozone.
The apparatus may include a separate power supply 318 (e.g., in lieu of a generator, see
The power supply 318 preferably includes an onboard intelligence 324 which enables the power supply 318 to adjust to changing conditions within the reaction unit 316. In embodiments with a generator, the onboard intelligence 324 operates independently. In this manner, the levels of reactive oxygen species generated within the reaction unit 316 can be maintained at desired levels regardless of changing conditions within the reaction unit 316. For example, the onboard intelligence 324 of the power supply 318 can compensate for variables that may affect the output of the reaction unit 316, such as changes in moisture content of the air to be sanitized or dust buildup within the reaction unit 316.
Further, the onboard intelligence 324 may allow for the dialing up and down of the levels of reactive oxygen species generated by the reaction unit 316. Preferably, the amount of reactive oxygen species generated by the reaction unit 316 is adjustable while maintaining continuous power to the reaction unit 316. However, one skilled in the art will recognize that the desired levels of reactive oxygen species may also be obtained by turning the reaction unit 316 on and off periodically.
The environment control unit 42 further includes a reactive oxygen species sensor 328 located adjacent the outlet 210 (see
The level of ozone maintained in the cargo space 40 into which the sanitized air containing ozone is dispersed may vary from as low as 0.02 PPM to higher levels depending on regulations and operating conditions based on products in the cargo space 40.
Turning back to
The controller 430 regulates the environment control system, in order to regulate the environment of the cargo space 40. Referring to
As will be shown below, the display screen 442 and the keypad 446 allow the user to identify the products or cargo, and the cargo identification is received by the controller 430. The cargo identification represents the products that will be hauled as cargo and stored in the cargo space 40. The user may identify, for example, cargo such as “Potatoes” or “Fish.” One way for the user to identify cargo is by making a selection from a menu, as will be described below. After the controller 430 receives the user's cargo identification, the controller retrieves the environment-control parameters as a function of the identified cargo from the database 438, or from a non-resident database. The controller 430 regulates the environment control system, and thereby regulates the cargo space 40, based upon the retrieved parameters.
Eight examples of environment-control parameters 452 are shown, but any data for any number of parameters may be included in the database 438. The illustrated environment-control parameters include the set point temperature and reactive oxygen species concentrations (ROS). Different kinds of cargo are best shipped at different temperatures. For example, frozen beef may be shipped at five degrees F. (−15 degrees C.) while bananas may be shipped at fifty-four degrees F. (12 degrees C.). Another environment-control parameter is an acceptable temperature range, i.e., the acceptable variance from the set point temperature. Some types of cargo, such as oranges, can be shipped at a wide range of temperatures, while other types of cargo, such as bananas, are more sensitive to temperature variations and are best transported in a narrow range of temperatures.
Some kinds of cargo require no data in the database 438 for a particular parameter. For example, light may be an unimportant factor when the cargo is fish, and thus there may be no light-regulation parameter stored in the database 438 as a function of the cargo “Fish.” As one skilled in the art will understand, many features could be controlled via the database 438, as desired. The environment-control parameters shown in
In operation, the user selects a product from the HMI 52 which communicates with the controller 430 to control the environment control unit 42. In response to the selected product, the environment control unit 42 operates to maintain the desired environment-control parameters including temperature, humidity, reactive oxygen species concentrations, and other parameters, as desired.
The operation of the reaction unit 316 is based on at least one operating condition of the environmental control unit 42. For example, in one embodiment, the controller 430 operates the reaction unit 316 to produce reactive oxygen species only when the controller 430 operates the environmental control unit 42. In another embodiment, the controller 430 operates the reaction unit 316 such the reaction unit 316 only produces the reactive oxygen species when the controller 430 operates the environment control unit 42 in one of the COOLING mode and the HEATING mode. Furthermore, when the environmental control unit 42 is in the DEFROST mode, the controller 430 deactivates the reaction unit 316.
The controller 430 delays the operation of the reaction unit 316 until after a predetermined time period after the controller 430 operates the environment control unit 42 in the COOLING mode during a pull down operation to allow the environmental control unit 42 to remove moisture from air within the cargo space 40. The controller 430 also operates the reaction unit 316 such the reaction unit 316 begins producing the reactive oxygen species after the predetermined time period.
The environmental control unit 42 can also operate in a CLEAN mode wherein the reaction unit 316 provides the reactive oxygen species into air within the housing 44 and the reactive oxygen species are generated and discharged upstream of the evaporator coil 168 such that the reactive oxygen species flow over the evaporator coil 168 and/or other components for cleaning.
The controller 430 is responsive to the return air temperature sensor 206 to deactivate the reaction unit 316 when the detected temperature is below a threshold temperature. Additionally, the controller 430 may respond to other temperature sensors (e.g., evaporator, supply, cargo space) to deactivate the reaction unit 316 when a temperature below a threshold temperature is detected. Furthermore, the humidity within the cargo space 40 and the housing 44 may be monitored and the reaction unit 316 may be operated only when the humidity level is acceptable. For example, the reaction unit 316 may only be operated below a threshold humidity.
The evaporator fan 200 is an air moving device and may be positioned in a different location within the housing 44. When the evaporator fan 200 operates, conditioned air and reactive oxygen species are distributed from the housing 44 into the cargo space 40.
The controller 430 receives the signals sent by the reactive oxygen species sensor 328 and controls the amount of reactive oxygen species generated by the reaction unit 316 based on the detected concentration of reactive oxygen species. Specifically, the illustrated embodiment, detects the level of ozone and operates the reaction unit 316 to maintain a desired level of ozone. When operating, the evaporator fan 200 is solely responsible for moving air through both the evaporator 168 and the reaction unit 316.
The environmental control unit 42 may also include a transmitter and a receiver in communication with the controller 430. The transmitter and receiver allow the environmental control unit 42 to communicate wirelessly with a remote location. For example, the environmental control unit 42 may output operation parameters and conditions to a remote monitoring station or a user such that a particular load may be monitored while in transit. Further, the receiver may receive signals from the remote location to control the environmental control unit 42. For example, the user may desire to change an operating parameter of the environmental control unit 42 from the remote location to better protect a product in the cargo space 40.
Various features and advantages of the invention are set forth in the following claims.
