Water Flow Characteristics — Water-hammer
時(shí)間：2016-07-09 10:39:12點(diǎn)擊：次
When a pipe contains a column of moving liquid, considerable kinetic energy is stored in the liquid by virtue of its mass and velocity. If the velocity is suddenly destroyed by the quick closing of a valve this energy cannot be absorbed because liquid is nearly incompressible. Therefore, an instantaneous shock is created which may represent excessively high pressures. Maximum pressure caused by water-hammer may be calculated with the following formulae:
Pwh = pressure surge, psi
V = maximum velocity change, ft./sec.
gc = acceleration of gravity, 32.2 ft./sec.2
K = luid bulk modulus, 300,000 PSI for water
d = pipe inside diameter, inches
b = wall thickness, inches
This is what should be reviewed when a plastic piping system is being considered.
? Speed of opening or closing of regulating type valves.
? Action of pumps starting or stopping.
? Movement of entrapped air through the system.
Understanding the concept of water-hammer and designing the system to minimize it is the best possible preventive measure. A few tips to consider when attempting to reduce the causes of surge in a piping system are:
? Keep fluid velocities under 5 feet per second. (see pages 7.08 ~ 7.11)
? Check the cycling time of valves to prevent abrupt changes in flow. Both manual and actuated valving should be checked for speciic closing times.
? Evaluate low at pump start-up and during spin-down. Also determine how much air, if any, is introduced during pump startup.
? Use properly sized vacuum breaker-air relief valves to control the amount of air that is admitted or exhausted throughout the system.
SPECIFIC INSIDE DIAMETERS OF PIPE
下一篇：Installation Ⅱ
- About Us
Company profile
Culture
Enterprise image
Company honors
Organizations
Video
- Strength
Plant Workshop
Design center
Innovation mode
Quality guarantee
- Standard
Advantages
Usage
Construction standard
Notice
- Technical
- Network
- Contact Us
Mobile Scanning
Wecat Scanning
Copyright ? 2017 Zhejiang Huangyan Minghua Plastic Pipe Fittings Co.,Ltd.All Rights Reserve. 浙ICP備11019802號(hào)-1 浙公網(wǎng)安備 33100302000346號(hào) XML | Sitemap Power By：Galaxy