since knowledge on hydrodynamic torque of a butterfly valve is very important for butterfly valve design, its hydrodynamic torque is investigated in this paper. in reality, the investigation of the loss coefficient and torque from some experiments will take a long time and a lot of money. this paper presents a statistical study of the flow past the butterfly valve in a static analysis using com...

Water-hammer is a transient condition which may occur in a network as a result of rapid or slow valve closures, pump failures, changes in turbine loading, etc. It creates high and low pressure waves which travel along the system and decay as a result of wall shear stress. Comparison o experimental and theoretical results revealed the failure of steady or quasi-steady models in correctly predict...

T a new major technological advance is available that can help control-valve users avoid many of the problems and inefficiencies associated with using compressed air as a power medium. The new solution uses electric power and eliminates dependence on compressed air. This totally electric solution is appropriate and cost-effective for a wide variety of control-valve applications, including those...

Water-hammer is a transient condition which may occur in a network as a result of rapid or slow valve closures, pump failures, changes in turbine loading, etc. It creates high and low pressure waves which travel along the system and decay as a result of wall shear stress. Comparison o experimental and theoretical results revealed the failure of steady or quasi-steady models in correctly predict...

In water supply systems, One of the most important components as safety unit and the current controller (Switching flow and regulate the amount of flow) used in the arrangement of lines of water. In this study, according to multiple ponds in Tanguiyeh dam water pipeline to industrial and mining company Gol Gohar Sirjan Butterfly valve used in these ponds using Fluent software simulation has bee...

A silencer to attenuate engine exhaust noise using active control methods is developed. The device consists of an electrically driven valve, combined with a buffer volume, which is connected to the exhaust outlet. Using the mean flow through the valve and the pressure fluctuations in the volume, the valve regulates the flow in such a way that only the mean flow passes through the exhaust outlet...

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...

OBJECTIVES Development of an intraluminal device to reduce aortic regurgitation could provide a strategy intermediate between medical treatment and aortic valve replacement. An initial prototype and a testing system have been designed. METHODS Aortic valves obtained from heart transplant recipients were explanted and assessed in a mock circulatory loop with resistive and capacitive elements, ...

BACKGROUND Intraluminal occlusion is common in children with central venous catheters (CVCs). Although multiple factors predispose CVCs to occlusion, reflux of blood is frequently implicated. We hypothesized that use of either a single-valve or positive-pressure-valve needleless connector device would reduce CVC occlusion rates in comparison to a standard device. We further hypothesized that sa...