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Novel real-time diagnosis of the freezing process using an ultrasonic transducer.

Tseng YH, Cheng CC, Cheng HP, Lee D - Sensors (Basel) (2015)

Bottom Line: The temperature was also adopted for evaluating the cooling and freezing periods.These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing).This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy.

View Article: PubMed Central - PubMed

Affiliation: Department of Energy and Refrigerating Air-Conditioning Engineering, National Taipei University of Technology, Taipei 10608, Taiwan. yhtntut@gmail.com.

ABSTRACT
The freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products. This paper presents an integrated ultrasonic transducer (UT) in a stainless steel bottle and its application to real-time diagnostics of the water freezing process. The sensor was directly deposited onto the stainless steel bottle using a sol-gel spray technique. It could operate at temperature range from -100 to 400 °C and uses an ultrasonic pulse-echo technique. The progression of the freezing process, including water-in, freezing point and final phase change of water, were all clearly observed using ultrasound. The ultrasonic signals could indicate the three stages of the freezing process and evaluate the cooling and freezing periods under various processing conditions. The temperature was also adopted for evaluating the cooling and freezing periods. These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing). This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy.

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Related in: MedlinePlus

Schematic view of the freezing bottle with UT illustrating the ultrasound transmission paths between the bottle/water or ice. A temperature sensor was set in the middle of the freezing bottle for measuring the water/ice temperature.
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sensors-15-10332-f002: Schematic view of the freezing bottle with UT illustrating the ultrasound transmission paths between the bottle/water or ice. A temperature sensor was set in the middle of the freezing bottle for measuring the water/ice temperature.

Mentions: A schematic view of the freezing bottle with the UT sensor incorporated in the freeze dryer machine during the freezing process is displayed in Figure 2. As shown in Figure 2, when electric pulses were applied to the piezoelectric film through the top and bottom electrodes, where the freezing bottle itself served as the bottom electrode, ultrasonic waves were excited and transmitted into the freezing bottle. Ln (n = 1, 2,…) denote the nth round trip longitudinal-wave ultrasonic echoes reflected from the interface of the freezing bottle/water or ice, and Lw is the 1st echo propagating in the water and reflected from the water/air interface. The L1 and Lw echoes will be used to monitor the freezing process and water state. The height of water level and thickness of bottle bottom are denoted as h and d, respectively. A temperature sensor (Type T thermocouple, Omega, Stamford, CT, USA) was set in the middle of the freezing bottle for measuring the water/ice temperature. The temperature would be measured for a comparison with the ultrasonic signals during the freezing process.


Novel real-time diagnosis of the freezing process using an ultrasonic transducer.

Tseng YH, Cheng CC, Cheng HP, Lee D - Sensors (Basel) (2015)

Schematic view of the freezing bottle with UT illustrating the ultrasound transmission paths between the bottle/water or ice. A temperature sensor was set in the middle of the freezing bottle for measuring the water/ice temperature.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481992&req=5

sensors-15-10332-f002: Schematic view of the freezing bottle with UT illustrating the ultrasound transmission paths between the bottle/water or ice. A temperature sensor was set in the middle of the freezing bottle for measuring the water/ice temperature.
Mentions: A schematic view of the freezing bottle with the UT sensor incorporated in the freeze dryer machine during the freezing process is displayed in Figure 2. As shown in Figure 2, when electric pulses were applied to the piezoelectric film through the top and bottom electrodes, where the freezing bottle itself served as the bottom electrode, ultrasonic waves were excited and transmitted into the freezing bottle. Ln (n = 1, 2,…) denote the nth round trip longitudinal-wave ultrasonic echoes reflected from the interface of the freezing bottle/water or ice, and Lw is the 1st echo propagating in the water and reflected from the water/air interface. The L1 and Lw echoes will be used to monitor the freezing process and water state. The height of water level and thickness of bottle bottom are denoted as h and d, respectively. A temperature sensor (Type T thermocouple, Omega, Stamford, CT, USA) was set in the middle of the freezing bottle for measuring the water/ice temperature. The temperature would be measured for a comparison with the ultrasonic signals during the freezing process.

Bottom Line: The temperature was also adopted for evaluating the cooling and freezing periods.These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing).This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy.

View Article: PubMed Central - PubMed

Affiliation: Department of Energy and Refrigerating Air-Conditioning Engineering, National Taipei University of Technology, Taipei 10608, Taiwan. yhtntut@gmail.com.

ABSTRACT
The freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products. This paper presents an integrated ultrasonic transducer (UT) in a stainless steel bottle and its application to real-time diagnostics of the water freezing process. The sensor was directly deposited onto the stainless steel bottle using a sol-gel spray technique. It could operate at temperature range from -100 to 400 °C and uses an ultrasonic pulse-echo technique. The progression of the freezing process, including water-in, freezing point and final phase change of water, were all clearly observed using ultrasound. The ultrasonic signals could indicate the three stages of the freezing process and evaluate the cooling and freezing periods under various processing conditions. The temperature was also adopted for evaluating the cooling and freezing periods. These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing). This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy.

Show MeSH
Related in: MedlinePlus