PRESSURE CONTROL VS VOLUME CONTROL

1994 ◽  
Vol 22 (1) ◽  
pp. A89
Author(s):  
Kenneth Davis ◽  
Richard D. Branson ◽  
David T. Porembka
2012 ◽  
Vol 203 ◽  
pp. 18-21
Author(s):  
Hui Fang ◽  
Wei Tang ◽  
Yan Jing Meng

The paper analyzes the method of direct tension control, provides repaired method of closed loop speed for tension control of underfeed winder, and designs the systematic hardware figuration and software to effectively meet the demands of different volume control. Furthermore, the problems including pressure control of pressing roller, load distribution control of two-drum winder, tension control of paper, and dynamic compensation control were analyzed and solved through the design of hardware and software of S7-300 PLC.


2021 ◽  
Author(s):  
Emre Badur ◽  
Mustafa Altınay ◽  
Pınar Sayın ◽  
Ayşe Surhan Çınar ◽  
leyla türkoğlu ◽  
...  

Abstract Background: To compare the volume-controlled and pressure-controlled ventilation modes with near infrared spectroscopy (NIRS) cerebral oximetry and blood gas status in laparoscopic cholecystectomyMethods: Seventy patients (n=70), who underwent elective laparoscopic cholecystectomy operation were randomized into two groups (volume control ventilation - group V, pressure control ventilation - group P). Demographic data (age, gender, body mass index) and operative data (anesthesia, surgery, and insufflation durations) were recorded. Patients’ single derivation electrocardiogram, pulse oximetry, non-invasive arterial pressure, NIRS cerebral oximetry and end-tidal CO2 parameters were recorded. Measurements were done at the start of anesthesia (T0), at the end of intubation (T1), 5 minutes after the insufflation (T2), at the time just before desufflation (T3) and 5 minutes after desufflation (T4).The patients’ heart rate, systolic and diastolic arterial pressure, saturation of pulse oximetry, and NIRS values were recorded for time points. Additionally, arterial gas results and mechanical ventilation parameters were recorded as well. Results: No significant difference was found in age, sex, body mass index. Operation, anesthesia and insufflation durations were similar for the groups. In Group P, NIRS right T1-2-3 averages and NIRS left T2-3 averages were significantly higher than Group V (p=0.030, p=0.001, p=0.001, p=0.006, p=0.002 respectively). In Group P T1-T2-T4, mean peak pressures and mean plateau pressures were significantly lower than Group V (p=0.003, p=0.001, p<0.001, p=0.011, p=0.001, p<0.001 respectively).Conclusion: Mechanical ventilation that performed in pressure-control ventilation mode is resulted with better tissue oxygenation than volume-control ventilation mode. In pressure-control ventilation mode, peak pressure and plateau pressure were lower.Registration of study at ClinicalTrials.gov was made at 25/01/2021 with the NCT04723043 number.


1988 ◽  
Vol 31 (1) ◽  
pp. 56-61
Author(s):  
Atsushi Takahashi ◽  
Takao Okada

This study discusses various control systems that can keep the room pressure and supply/exhaust airflow rate at constant levels in "other rooms" of a highly airtight containment facility when the supply/exhaust airflow is shut off in one of the rooms for decontamination purposes. This study has shown that the constant air volume control system (CAV) allows hysteresis to occur at small differentials on the performance curve of the static pressure differentials and that this hysteresis can cause wide fluctuations in room pressure. In contrast, the variable air volume, central processing unit (VAV-CPU) control system can maintain both airflow rates and room pressures. Each room pressure was controllable to the set level, with an error of less than ±0.5 mmH2O even during transient distur bances. This control system limited fluctuations in the airflow to and from each room to 5 percent during the transient responses. This control system also allows power savings in the operation of supply/exhaust fans, because of the reduced airflow rate and the static pressure of the fans, and is considered to be an excellent control system.


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