This paper discusses the influence of the radial clearance of the poppet of the direct spring operated pressure relief valve type DPRS06K315 on the dynamic behaviour of the valve. The mathematical model of the valve has been developed; these mathematical terms have been represented in Matlab/SIMULINK. The results obtained by a simulation describe dynamic behaviour of the valve and its influence...

Background: Heart valve disease gradually increases the pressure in the heart chambers and impairs heart pumping. It influences on quality of life due to low output, disability, fear, amnesia, anxiety, and depression. Although most of signs and symptoms in patients with heart valve diseases may significantly decrease after valve replacement surgery, there is limited information about the impact...

BACKGROUND Bubble CPAP is frequently used in spontaneously breathing infants with lung disease. Often bubble CPAP systems lack pressure alarms and pressure-release valves. We observed a large volume of condensate in the exhalation limb of a patient circuit and conducted a series of experiments to test the hypothesis that accumulated condensate could affect delivered pressures. METHODS An anat...

Transluminal balloon valvuloplasty was used to treat congenital pulmonary valve stenosis in 20 patients. Follow-up cardiac catheterization was performed in 11 patients at intervals of from 2 to 12 months after the procedure. Peak systolic pressure gradient across the pulmonic valve decreased from 68 +/- 27 to 23 +/- 5 mm Hg (p less than .001) after valvuloplasty. There were no complications. Fo...

Vent vacuum relief valves (VRVs) are used to limit the negative pressure at the ventricular vent catheter tip as well as prevent reversal of blood flow and prevention of air embolism. The purpose of this study was to evaluate the performance of three commercially available ventricular vent valves. The negative pressure at which the vent valve opened was measured at the valve inlet using high-fi...