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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 freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products.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

Amplitude variations of ultrasonic L4 and Lw echoes during the freezing process, indicating the water-in, freezing point (ice crystals) and phase change end during the freezing process. Water level: 25 mm; room temperature: 25 °C; shelf temperature: −30 °C; air pressure: 101.3 kPa.
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sensors-15-10332-f007: Amplitude variations of ultrasonic L4 and Lw echoes during the freezing process, indicating the water-in, freezing point (ice crystals) and phase change end during the freezing process. Water level: 25 mm; room temperature: 25 °C; shelf temperature: −30 °C; air pressure: 101.3 kPa.

Mentions: In order to investigate the correlation between the ultrasonic signals observed and the water freezing process, the amplitude values of the L4 and Lw echoes in Figure 3a with respect to the process time were obtained. The results are presented in Figure 7. The reason of choosing ultrasonic echo L4, instead of L1, is that the L4 echo is more sensitive to the variation of steel/water interface. The amplitude variations of the ultrasonic L4 and Lw echoes, corresponding to the freezing process in Figure 6, are described as follows:(1)


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

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

Amplitude variations of ultrasonic L4 and Lw echoes during the freezing process, indicating the water-in, freezing point (ice crystals) and phase change end during the freezing process. Water level: 25 mm; room temperature: 25 °C; shelf temperature: −30 °C; air pressure: 101.3 kPa.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-10332-f007: Amplitude variations of ultrasonic L4 and Lw echoes during the freezing process, indicating the water-in, freezing point (ice crystals) and phase change end during the freezing process. Water level: 25 mm; room temperature: 25 °C; shelf temperature: −30 °C; air pressure: 101.3 kPa.
Mentions: In order to investigate the correlation between the ultrasonic signals observed and the water freezing process, the amplitude values of the L4 and Lw echoes in Figure 3a with respect to the process time were obtained. The results are presented in Figure 7. The reason of choosing ultrasonic echo L4, instead of L1, is that the L4 echo is more sensitive to the variation of steel/water interface. The amplitude variations of the ultrasonic L4 and Lw echoes, corresponding to the freezing process in Figure 6, are described as follows:(1)

Bottom Line: The freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products.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