Cavitation And Flashing In Control Valves Pdf

cavitation and flashing in control valves pdf

File Name: cavitation and flashing in control valves .zip
Size: 2183Kb
Published: 28.04.2021

Control Valve Sizing is a procedure of deciding the appropriate type and size of the control valve to optimally satisfy the requirements of fluid flow management. The following control valve terminologies are required to define before we proceed for control valve sizing steps. Valve characteristics describe the relationship between valve travel and flow rate.

Control Valve Cavitation and Flashing

Flashing is the first stage of cavitation. However, it is possible for flashing to occur by itself without cavitation occurring. Flashing occurs in liquid flows when some of the liquid changes permanently into vapour. This is brought on by a reduction in pressure forcing the liquid to change to gaseous state. The reduction in pressure is caused by the restriction in the flowstream generating a higher flow rate through the restriction and therefore a reduction in pressure. A photograph showing a badly eroded valve plug from a cage-guided global valve reveals just how destructive flashing can be:. When flashing occurs, the flow from the outlet of the valve is composed of liquid and vapour.

Multi-Z – Severe Service Multi Stage Valves

To browse Academia. Skip to main content. By using our site, you agree to our collection of information through the use of cookies. To learn more, view our Privacy Policy. Log In Sign Up.

Flashing is the first stage of cavitation. However, it is possible for flashing to occur by itself without cavitation occurring. Flashing occurs in liquid flows when some of the liquid changes permanently into vapour. This is brought on by a reduction in pressure forcing the liquid to change to gaseous state. The reduction in pressure is caused by the restriction in the flowstream generating a higher flow rate through the restriction and therefore a reduction in pressure. When flashing occurs, the flow from the outlet of the valve is composed of liquid and vapour. With increased flashing, the vapour carries the liquid.

Flashing is the first stage of cavitation. However, it is possible for flashing to occur by itself without cavitation occurring. Flashing occurs in liquid flows when some of the liquid changes permanently into vapour. This is brought on by a reduction in pressure forcing the liquid to change to gaseous state. The reduction in pressure is caused by the restriction in the flowstream generating a higher flow rate through the restriction and therefore a reduction in pressure. A photograph showing a badly eroded valve plug from a cage-guided global valve reveals just how destructive flashing can be:. When flashing occurs, the flow from the outlet of the valve is composed of liquid and vapour.

Control Valve Sizing (pdf)

In refineries, the process media flowing through valves are primarily liquids. With liquids, critical operating conditions caused by cavitation or flashing may occur. Symptoms are, for instance, increased noise emission, valve and pipe component erosion or low-frequency mechanical vibration in the valve and the connected pipeline.

Multi-Z boiler feed-pump, recirculation control valve handles high-pressure drop applications wher entrained solids and cavitation are a problem. Multistage trim design eliminates cavitation and provides extended trim life. Severe service is defined as applications which have excessive noise, cavitation, erosion, or high pressure drops. Most valves in these categories require special design work, resulting in the use of special materials or trim designs. Flowserve offers the most comprehensive range of solutions to minimise or eliminate cavitation, erosion and noise.

Full Cavitation: Increases in vibration and Noise intensity to the level of "maximum vibration" vibration" "maximum. Super Cavitation: A decrease in noise and vibration. Choking often occurs in this area.

Control valves are subject to a number of common problems. This section is dedicated to an exploration of the more common control valve problems, and potential remedies.

1 COMMENTS

Declan A.

REPLY

C# for java developers pdf read 13 reasons why online pdf free

LEAVE A COMMENT