Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
  • F25D21/02—Detecting the presence of frost or condensate
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/11—Sensor to detect if defrost is necessary
  • F25B2700/111—Sensor to detect if defrost is necessary using an emitter and receiver, e.g. sensing by emitting light or other radiation and receiving reflection by a sensor

Definitions

• the present disclosure relates to a system, apparatus, and method for detecting an object or the lack of the presence of an object, including the detection of ice in an ice-forming apparatus or refrigeration case or system.
• ice is formed from an evaporator grid.
• the ice grows on the evaporator grid until it reaches a desirable size or thickness. Once the ice has reached the desired size or thickness, the ice is harvested from the evaporator grid, thereby separating ice cubes from the evaporator grid.
• the ice-forming apparatus determines when to harvest the ice, i.e., the harvest initiation point.
• One technique determines water conductivity. For example, an electrode or probe may be placed a precise distance away from the evaporator. As the ice forms, the water flowing over the evaporator eventually comes in contact with the probe. A conductive path via the water is formed between the electrode and the chassis of the machine (ground), thereby indicating that the ice has reached a predetermined size.
• These types of sensors have certain drawbacks. For instance, as scale forms on the probe, a parallel conductive path can be formed to ground. Furthermore, extremely pure water is not conductive, thereby reducing the effectiveness of the sensor.
• Another technique may utilize capacitive sensors.
• an electrode may be placed a precise distance away from the evaporator. As the ice forms, the water flowing over the evaporator eventually comes in contact with the probe. When the water comes in contact with the electrode, the capacitance changes and this change can be used to determine the harvest initiation point.
• Capacitive sensors used in this setting also suffer from certain drawbacks. For instance, scaling can interfere with the capacitance reading when dirty water is used in the ice-forming apparatus.
• a third technique is a batch system technique.
• the water level in a sump tank may be measured.
• the sump is filled to a predetermined point and then the pump is started and the ice starts to form.
• the level in the sump decreases.
• the harvest is initiated.
• the ice thickness may vary due to factors such as environmental conditions (temperature, humidity), level of total dissolved solids in the water (only the water freezes, not the minerals), and water loss in the sump (e.g.,, a leaking water dump valve).
• the batch system technique may not result in uniformly sized ice cubes from batch to batch.
• a system for determining when an amount of ice formed on an evaporator has reached a predetermined size includes an acoustic transmitter positioned proximate to the evaporator and an acoustic sensor coupled to the acoustic transmitter.
• the acoustic transmitter channels acoustic signals emanating from the evaporator to the acoustic sensor and the acoustic sensor generates an electronic signal indicative of the acoustic signal.
• the system further includes a receiver module coupled to the acoustic sensor and configured to receive the electronic signal, and determine that ice formed on the evaporator has reached a predetermined size based on the electronic signal.
• an ice-forming apparatus in another aspect of the disclosure, includes an evaporator grid, an acoustic transmitter positioned proximate to the evaporator grid, and an acoustic sensor coupled to the acoustic transmitter.
• the acoustic transmitter channels acoustic signals emanating from the evaporator grid to the acoustic sensor and the acoustic sensor generates an electronic signal indicative of the acoustic signal.
• the apparatus further includes a receiver module coupled to the acoustic sensor and configured to receive the electronic signal, and determine that ice formed on the evaporator grid has reached a predetermined size based on the electronic signal.
• a method for determining whether formed ice has reached a predetermined size includes receiving an electronic signal indicative of an acoustic signal, transforming the electronic signal from a time domain to a frequency domain, sampling one or more amplitudes of the transformed signal at one or more predetermined frequencies, and initiating one of a harvest operation and a defrost cycle based on the one or more sampled amplitudes.
• FIG. 1 is a drawing illustrating exemplary machinery of an ice-forming apparatus having an acoustical sensor system according to various embodiments of the disclosure
• FIGS. 2A and 2B are drawings illustrating an exemplary acoustic transmitter in an assembled view and in an exploded view, respectively, according to various embodiments of the disclosure
• FIG. 3 is a drawing illustrating an exemplary acoustic transmitter in an assembled view according to various embodiments of the disclosure
• FIG. 4 is a drawing illustrating an exemplary acoustic sensor system according to various embodiments of the disclosure.
• FIG. 5 is a flow chart illustrating an exemplary method for determining when formed ice has reached a predetermined size according to various embodiments of the disclosure.
• the current disclosure describes an apparatus that enables detection of objects or material (collectively, an "object” or “objects”).
• objects, articles, or material which may be detected by the apparatus and method include, but are not limited to, solid objects or material such as ice.
• object- or material-processing systems include, but are not limited to ice-forming machines and ice-collection bins of ice-making systems.
• Other example applications may include refrigeration cases, bins, freezers, display cases, and other devices or refrigeration storage containers, where the detection system may be used to detect an accumulation of ice and initiate a defrost procedure.
• FIG. 1 illustrates an exemplary ice-forming apparatus 100.
• An exemplary ice-forming apparatus 100 can include an evaporator 1 10, an acoustic transmitter 120 that transmits acoustic signals, a receiver module 130, and a flexible acoustical transmission tube 140 that channels the acoustic signals from the acoustic transmitter 120 to the receiver module 130.
• the receiver module 130 processes electronic signals corresponding to the acoustic signals and controls the evaporator 1 10 based thereon.
• the evaporator 1 10 can include an evaporator grid 160, an evaporator coil (not shown) and a cold plate (not shown).
• the evaporator grid 160 is used to form ice cubes. Water is pumped from a water reservoir (not shown) onto the cold plate, which is maintained at a temperature below a freezing temperature, e.g., less than thirty-two (32) degrees Fahrenheit or zero (0) degrees Celsius.
• the evaporator grid 160 can be formed in the shape of the ice that is to be harvested from the evaporator grid 160, e.g., a cubic or rectangular prism. When the ice has a desired depth or thickness, the ice can be harvested using known techniques. For instance, the evaporator grid 160 may be heated such that the formed ice cubes break and separate from the evaporator grid 160.
• the ice-forming apparatus 100 shown in Figure 1 can be a vertical ice- forming apparatus 100, wherein water flows from the top of the vertical ice- forming apparatus 100 over a vertical evaporator grid 160. It is appreciated that the techniques disclosed herein may be applied to any other type of ice-forming apparatuses 100 or to any other types of apparatus that incorporates an evaporator 1 10, e.g., a refrigeration apparatus and an air conditioner.
• the receiver module 130 controls whether the evaporator 1 10 is forming ice or harvesting ice. When the formed ice has reached a sufficient size or thickness, the receiver module 130 initiates a harvesting operation, e.g., instructs the evaporator 1 10 to heat the evaporator grid 160 to harvest the ice.
• the receiver module 130 can be configured to receive electronic signals indicative of the acoustic signals channeled from the acoustic transmitter 120.
• an acoustic sensor can receive an acoustic signal and generate the electronic signal corresponding to the acoustic signal. The acoustic signal (and the electronic signal) can provide an indication of the size of the formed ice, e.g. the depth or thickness of the formed ice.
• the receiver module 130 processes the electronic signal received from the acoustic sensor to sample the amplitude of the electronic signal at certain predetermined frequencies.
• the receiver module 130 determines that the formed ice has reached sufficient size or thickness and initiates a harvesting operation.
• the receiver module 130 determines that the harvest initiation point has been reached and initiates the harvest.
• the acoustic transmitter 120 can be positioned in proximity to the evaporator grid 160.
• the focal points of the diaphragm of the acoustic transmitter discussed in greater detail below, can be positioned to face the evaporator grid 160.
• the acoustic transmitter 120 may pick up and transmit the background noise or frequencies of the ice-forming apparatus 100, or other device or machinery within which it is installed. As the ice grows, the ice can form and grow towards the acoustic transmitter 120. Once the ice physically touches the acoustic transmitter 120, there is a significant increase in the amplitude of the noise signal generated by the ice-forming apparatus 100, e.g., noise resulting from mechanical vibration from the ice-forming apparatus 100.
• the noise emanating from the ice- forming apparatus 100 is transferred via the air and the amplitude of the noise signal is reduced.
• the acoustic signals that are picked up by the acoustic transmitter 120 can be transferred to an acoustic sensor (not shown) via the flexible acoustical transmission tube 140.
• the acoustic transmitter 140 can be used to measure the "bridge thickness" of the ice.
• the diaphragm of the acoustic transmitter 120 can be placed relatively close to the evaporator grid 160, e.g., one-eight (1 /8) of an inch, so as to measure the bridge thickness.
• the bridge thickness is indicative of the overall depth or thickness of the formed ice.
• a wall 150 can separate the receiver module 130 and other electronics from the evaporator 1 10.
• an acoustic sensor e.g., a microphone
• a microphone can be located at the evaporator grid 160 side of the wall 150, or at the receiver module 130, such that the acoustic signal is transferred to the acoustic sensor via the flexible acoustical transmission tube 140.
• the acoustic transmitter 120 may be placed proximate to an evaporator 1 10 of a refrigeration case, a refrigeration bin, a freezer, a refrigeration display case, and other types of refrigerated storage containers.
• the acoustic transmitter 120 can be positioned near an area of the evaporator 1 10 where ice typically accumulates, e.g., the fins of the evaporator 1 10, so that the receiver module 130 can determine whether the accumulated ice has exceeded a predetermined level.
• the receiver module 130 can initiate a defrost operation, such as commencing a defrost cycle.
• the acoustic transmitter 120 can include an acoustic transmitter frame 210, an acoustic diaphragm 220, a flexible acoustical transmission tube 140, an interface 240 that couples the flexible acoustical transmission tube 140 to the acoustic diaphragm 220, and a height-adjustment screw 250.
• the acoustic transmitter 120 includes the acoustic transmitter frame 210 and the acoustic diaphragm 220.
• the acoustic transmitter frame 210 can include a substantially circular portion that forms an acoustical chamber 260.
• the substantially circular portion receives the acoustic diaphragm 220.
• the acoustic chamber 260 can be formed in any suitable shape.
• the acoustic diaphragm 220 can be a thin membrane that vibrates when the pressure caused by sound waves is imparted on the acoustic diaphragm 220.
• the vibration of the acoustic diaphragm 220 causes an acoustic signal, e.g., a sound wave, to reverberate throughout the acoustical chamber 260.
• the acoustic diaphragm 220 can include a plurality of focal points 230-A and 230-B.
• the focal points 230-A and 230-B can be positioned facing and substantially parallel to the evaporator grid 160 (FIG. 1 ).
• the acoustic transmitter frame 210 can include the interface 240, which is configured to receive the flexible acoustical transmission tube 140.
• the flexible acoustical transmission tube 140 can be forcibly inserted onto or into the interface 240, such that acoustic signals amplified by the acoustic diaphragm 220 are channeled to the acoustic sensor through the flexible acoustical transmission tube 140.
• the acoustical signals can be received by the acoustic sensor which outputs electrical signals indicative of the acoustic signal to the receiver module 130.
• the acoustic transmitter 120 can include a height-adjustment screw 250.
• the height-adjustment screw 250 can protrude perpendicularly from the frame 210.
• the height-adjustment screw 250 can be utilized to adjust a distance between the acoustic transmitter 120 and the evaporator grid 160.
• the height- adjustment screw 250 can be inserted into an opening in the frame 210.
• the height-adjustment screw 250 can be screwed in to increase the distance between the acoustic transmitter 120 and the evaporator grid 160. It should be appreciated that other means for controlling the distance between the acoustic transmitter 120 and the evaporator grid 160 are contemplated and are within the scope of this disclosure.
• the acoustic transmitter 120 of FIGS. 2A and 2B are provided for example only and not intended to be limiting. Variations of the acoustic transmitter 120 are contemplated and are within the scope of the disclosure.
• FIG. 3 illustrates an alternative embodiment of an acoustic transmitter 300.
• components appearing in the acoustic transmitter 120 of FIGS. 2A and 2B and in the acoustic transmitter 300 of FIG. 3 have been provided the same reference numbers.
• the acoustic transmitter 300 may include an acoustic sensor 270 coupled to the interface 240.
• the acoustic sensor 270 can be mounted to the interface 240 such that the acoustic signals emanating from the acoustic diaphragm 220 are channeled directly to the acoustic sensor 270.
• the acoustic sensor 270 receives the acoustic signal and outputs an electronic signal indicative of the received acoustic signal to the receiver module 130.
• the acoustic sensor 270 can be any suitable microphone. It should be further appreciated that other types of acoustic sensors 270 can be used, such as sound transducers or piezoelectric transducers.
• FIG. 4 illustrates an example acoustic transmitter system 400.
• the acoustic transmitter system 400 can include the acoustic transmitter 120, the flexible acoustical transmission tube 140, the acoustic sensor 270, the receiver module 130, and a housing 410.
• the exemplary acoustic transmitter 120 described with respect to FIGS. 2A and 2B is connected to the receiver module 130 by the acoustical transmission tube.
• the receiver module 130 includes an acoustic sensor 270, a circuit board assembly 420, and a receiver clip 430, all of which can be housed in the housing 410.
• the receiver clip 430 is any suitable fastener that fastens the flexible acoustical transmission tube 140 to the acoustic sensor 270. It is appreciated that other acoustic sensors can be used, such as sound transducers or piezoelectric transducers.
• the acoustic signals are channeled from the acoustic transmitter 120 to the acoustic sensor 270, which converts the received acoustic signal into an electronic signal that is able to be processed by the receiver module 130, e.g., a digital signal.
• the acoustic transmitter 120 can be placed proximate to an evaporator grid 160 (FIG. 1 ). It should be appreciated that while the acoustic transmitter 120 is explained as being proximate to an evaporator grid 160, the techniques disclosed herein are applicable to any type of evaporator 1 10. In some embodiments, the acoustic transmitter 120 can be positioned such that the focal points 230-A and 230-B (FIGS. 2A and 2B) of the acoustic diaphragm 220 (FIGS. 2A and 2B) face the evaporator grid 160. The acoustic sensor 270 may be coupled to the acoustic transmitter 120.
• the flexible acoustical transmission tube 140 is interposed between the acoustic transmitter 120 and the acoustic sensor 270.
• the acoustic transmitter 120 channels acoustic signals emanating from the evaporator grid 160 to the acoustic sensor 270.
• the acoustic sensor 270 can generate an electronic signal indicative of the acoustic signal, which is provided to the receiver module 130.
• the receiver module 130 can be electrically coupled to the acoustic sensor 270 such that the receiver module 130 is configured to receive the electronic signal.
• the receiver module 130 can be further configured to determine that ice formed on the evaporator grid 160 has reached a predetermined size based on the electronic signal.
• amplitude of the acoustic signal transmitted by the acoustic transmitter 120 may increase.
• the receiver module 130 can continuously monitor the amplitudes of the electronic signal to determine when to initiate an ice harvesting operation or a defrost operation.
• the receiver module 130 can be configured to transform the electronic signal to a frequency domain and sample one or more amplitudes of the transformed electronic signal at one or more predetermined frequencies. In some of these embodiments, the receiver module 130 can compare each of the one or more sampled amplitudes to a corresponding predetermined amplitude threshold, such that when one or more of the sampled amplitudes exceeds its corresponding predetermined amplitude threshold, the receiver module 130 determines that the ice has reached the predetermined size. In other embodiments, the receiver module 130 can determine that the ice has reached the predetermined size when all of the sampled amplitudes exceed their corresponding predetermined amplitude thresholds.
• the frequencies at which the amplitudes may be sampled are determined during a testing phase.
• the frequencies at which the amplitudes may be sampled are determined during a testing phase.
• the machinery of the ice-forming apparatus 100, or other pertinent factors, such as the compressor operating frequency of the ice-forming apparatus 100 one or more frequencies are determined to be appropriate for sampling.
• the amplitudes can be sampled at 60 Hz, 120 Hz, 180 Hz, and 240 Hz.
• the amplitude thresholds for a particular ice- cube size that correspond to the predetermined frequencies are also determined. For instance, for a first frequency, a first amplitude threshold can be determined, for a second frequency, a second amplitude threshold can be determined, etc., to an nth frequency, for which an nth amplitude threshold can be determined.
• the receiver module 130 can be configured to sample the transformed electronic signal at the frequencies and to determine whether the ice is ready for harvesting based on the amplitudes of the electronic signal at the frequencies.
• FIG. 5 illustrates an exemplary method 500 that may be executed by the receiver module 130.
• the method 500 may start executing when the ice- forming apparatus 100 is operating in a freezing mode or when a refrigeration case or system is operating in a cooling cycle.
• the receiver module 130 can receive the electronic signal indicative of the acoustic signal from the acoustic sensor 270.
• the receiver module 130 can transform the electronic signal to the frequency domain.
• a Fast Fourier Transform FFT
• the receiver module 130 can implement a Discrete Fourier Transform, Laplace Transforms, or Z-Transforms to transform the electronic signal to the frequency domain.
• the receiver module 130 can sample the transformed electronic signal at one or more predetermined frequencies.
• the receiver module 130 can compare each of the sampled frequencies to a corresponding frequency threshold. If the amplitudes at a predetermined number of frequencies exceed their respective frequency threshold, the receiver module 130 can determine that the formed ice is of sufficient size and/or thickness. In this scenario, the receiver module 130 can initiate a harvest event or a defrost cycle, as shown at 518. It should be appreciated that in some embodiments, the receiver module 130 may require that all of the sampled amplitudes exceed their respective frequency threshold, or one, two, three, or more amplitudes exceed their respective frequency thresholds. If the receiver module 130 determines that the requisite number of amplitudes exceeding the respective amplitude threshold was not met, the receiver module 130 returns to 510.
• module may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC); an electronic circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes code; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.
• ASIC Application Specific Integrated Circuit
• FPGA field programmable gate array
• processor shared, dedicated, or group
• the term module may include memory (shared, dedicated, or group) that stores code executed by the processor.
• code may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, and/or objects.
• shared means that some or all code from multiple modules may be executed using a single (shared) processor. In addition, some or all code from multiple modules may be stored by a single (shared) memory.
• group means that some or all code from a single module may be executed using a group of processors. In addition, some or all code from a single module may be stored using a group of memories.
• the apparatuses and methods described herein may be implemented by one or more computer programs executed by one or more processors.
• the computer programs include processor-executable instructions that are stored on a non-transitory tangible computer readable medium.
• the computer programs may also include stored data.
• Non-limiting examples of the non-transitory tangible computer readable medium are nonvolatile memory, magnetic storage, and optical storage.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
• Production, Working, Storing, Or Distribution Of Ice (AREA)

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• 2012
  • 2012-02-08 CN CN201280008385.5A patent/CN103459947B/zh not_active Expired - Fee Related
  • 2012-02-08 EP EP12745318.1A patent/EP2673580A4/fr not_active Withdrawn
  • 2012-02-08 WO PCT/US2012/024336 patent/WO2012109360A2/fr active Application Filing
  • 2012-02-08 US US13/368,814 patent/US20120198864A1/en not_active Abandoned

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