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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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Effect of freezing speed on amplitude variation of ultrasonic L4 echo during the freezing process. Shelf temperatures: (a) −20; (b) −30 and (c) −40 °C. Water level: 25 mm; air pressure: 101.3 kPa.
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sensors-15-10332-f013: Effect of freezing speed on amplitude variation of ultrasonic L4 echo during the freezing process. Shelf temperatures: (a) −20; (b) −30 and (c) −40 °C. Water level: 25 mm; air pressure: 101.3 kPa.

Mentions: The freezing speed would affect the size of ice crystal nuclei and the frozen ice quality. We were interested in evaluating the effect of freezing speed on cooling/freezing periods indicated by ultrasonic signatures. To study this effect, the water level and air pressure were set at 25 mm and 101.3 kPa, respectively, under the shelf temperatures of −20, −30 and −40 °C. The lower shelf temperature represents the larger temperature difference and the faster cooling/freezing speed. The freezing speed of the freeze dryer machine was controlled by the programmable logical controller (PLC) under the setting of the PID controlling rule. The experimental results of water temperature and amplitude of ultrasonic L4 echo related to shelf temperatures of −20, −30 and −40 °C are shown in Figure 12 and Figure 13, respectively. Figure 12a–c are the temperature variation of water in the freezing bottle for shelf temperatures of −20, −30 and −40 °C, respectively. The freezing point and phase change end indicated by temperature occurred at the process times of 7.80, 6.98, 7.83 and 23.43, 15.98, 13.22 min for the shelf temperatures of −20, −30 and −40 °C, respectively.


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

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

Effect of freezing speed on amplitude variation of ultrasonic L4 echo during the freezing process. Shelf temperatures: (a) −20; (b) −30 and (c) −40 °C. Water level: 25 mm; air pressure: 101.3 kPa.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-10332-f013: Effect of freezing speed on amplitude variation of ultrasonic L4 echo during the freezing process. Shelf temperatures: (a) −20; (b) −30 and (c) −40 °C. Water level: 25 mm; air pressure: 101.3 kPa.
Mentions: The freezing speed would affect the size of ice crystal nuclei and the frozen ice quality. We were interested in evaluating the effect of freezing speed on cooling/freezing periods indicated by ultrasonic signatures. To study this effect, the water level and air pressure were set at 25 mm and 101.3 kPa, respectively, under the shelf temperatures of −20, −30 and −40 °C. The lower shelf temperature represents the larger temperature difference and the faster cooling/freezing speed. The freezing speed of the freeze dryer machine was controlled by the programmable logical controller (PLC) under the setting of the PID controlling rule. The experimental results of water temperature and amplitude of ultrasonic L4 echo related to shelf temperatures of −20, −30 and −40 °C are shown in Figure 12 and Figure 13, respectively. Figure 12a–c are the temperature variation of water in the freezing bottle for shelf temperatures of −20, −30 and −40 °C, respectively. The freezing point and phase change end indicated by temperature occurred at the process times of 7.80, 6.98, 7.83 and 23.43, 15.98, 13.22 min for the shelf temperatures of −20, −30 and −40 °C, respectively.

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