The timing of the valves of a hydraulic motor plays an important role in determining the throttling energy. To reduce this dominating energy loss, the timing of the valves must allow the fluid in the chamber to be precompressed and decompressed such that there is minimal pressure differential across the transitioning valve. The optimal valve timing to achieve precompression and decompression is...

The main objective of this paper is to study the characteristics of flow-induced noise in high pressure reducing valve (HPRV) and to provide some guidance for noise control. Based on computational fluid dynamics (CFD), numerical method was used to compute flow field. Ffowcs Williams and Hawkings Model was applied to obtain acoustic signals. The unsteady flow field shows that noise sources are l...

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...

One of the key factors affecting leakage in water distribution systems is network pressure management by putting Pressure Reduce Valves (PRV) in the flow path and optimal regulation of these vales in water networks. This study aimed at investigating optimal pressure management problems so as to minimize leakage in water distribution networks. To do so, an approach was proposed for both optimal ...

A total of 392 patients have undergone prosthetic valve surgery including the mitral valve over a four-year period (1972-76). Of these patients 56 (14%) had a pulmonary artery systolic pressure of 70 mmHg or more during preoperative cardiac catheterisation and the hospital mortality of this group was 5.4%. Similarly, the hospital mortality of the remaining 336 patients with a pulmonary artery p...

Water hammers seriously endanger the stability and safety of pipeline transportation systems, its protection mechanism has been a hotspot for research. In order to study change water hammer pressure caused by ball valve under different closing laws, computational fluid dynamics method was used perform transient numerical simulation times laws. The results show that faster speed in early stage, ...

The electromagnet pneumatic proportional servo valve is widely used in industrial automation, medical equipment, scientific composition detectors, and other fields that require precise adjustment of high-pressure air flow due to its simple working structure, large output power, frequency response, good control performance. However, the pressure small, making it vulnerable impact external enviro...

Case Description- An eleven-year-old Golden retriever male dog (dog I) and a four-year-old neutered Toy Terrier (dog II) were referred to Small Animal Clinic. Dog I was suffered from   partial loss of vision and engorgement of episcleral vessels of his right eye and dog II was blind. Intraocular pressure (IOP) of right eye was 37.8 mmHg in dog  I  and 34.5 and 31.6 mmHg in the right and left...

Valve switching is one of the most important power losses in digital hydraulics. In this paper, a dynamic Zero-Flowrate-Switching (ZFS) control method developed for hydraulic/pneumatic systems. The proposed strategy to actively reduce flowrate passing through valve zero before off valve. To realize it, an accessory line, which RLC oscillator applied generate sinusoidal flowrate, allocated paral...

UNLABELLED INTRODUCTION Symptomatic subdural hematoma development is a constant concern for patients who have undergone cerebrospinal fluid shunting procedures to relieve symptoms related to normal-pressure hydrocephalus. Acute subdural hematomas are of particular concern in these patients as even minor head trauma may result in subdural hematoma formation. The presence of a ventricular shun...