DynamicThe pressure classes of SABS

Dynamic
The pressure classes of SABS ISO 4427 HDPE pipes are based on constant internal
water pressures. HDPE pipes are however capable of handling dynamic pressure
events which exceed the values given by the classes but such occurrences can have
a negative effect on the standard 50 year life expectancy and in extreme cases can
result in product failure.
Water Hammer
Pipelines may be subjected to short-term increase in pressure above the normal
working pressure due to water hammer. Water hammer will occur in a pipeline
when its equilibrium is disturbed by rapid changes in flow conditions. Examples of
such conditions are; starting and stopping of pumps, rapid opening and closing of
valves, pipe failures, etc.
A rapid change in the velocity Av of water in the pipeline gives rise to a pressure
increase Ap according to the formula:
C
Ap = cAv/g
Where: c = the wave celerity (meters per second)
g = the acceleration due to gravity.
V )
The approximate wave celerities for HDPE pipes are as follows:

Kết quả (Anh) 1:

DynamicThe pressure classes of SABS ISO 4427 HDPE pipes are based on constant internalwater pressures. HDPE pipes are however capable of handling dynamic pressureevents which may exceed the values given by the classes but such occurrences can havea negative effect on the standard of 50 year life expectancy and in extreme cases canresult in product failure.Water HammerPipelines may be subjected to short-term increase in pressure above the normalworking pressure due to water hammer. Water hammer will occur in a pipelinewhen its equilibrium is disturbed by rapid changes in flow conditions. Examples ofsuch conditions are; starting and stopping of pumps, rapid opening and closing ofvalves, pipe failures, etc.A rapid change in the velocity of water in the Av pipeline gives rise to a pressureincrease Ap according to the formula:C AP = cAv/gWhere: c = the wave celerity (meters per second)g = the acceleration due to gravity.V)The approximate wave celerities for HDPE pipes are as follows:

Kết quả (Anh) 2:

Dynamic
The pressure classes of SABS ISO 4427 HDPE pipes are based on constant internal
water pressures. HDPE pipes are capable of handling dynamic pressure Tuy nhiên
mà events Exceed the values ​​given by the classes but such 'lần xảy ra can have
a negative effect on the standard 50 year life expectancy and extreme Cases can print
result printed product failure.
Water Hammer
lẽ Pipelines subjected to short-term pressure above the normal print tăng
working pressure Due to water hammer. Water hammer will occur in a pipeline
equilibrium is disturbed by its khi rapid flow changes conditionsEND_SPAN print. Examples of
such 'conditionsEND_SPAN are; starting and stopping of pumps, opening and closing of rapid
valves, pipe Failures, etc.
A rapid change in the velocity of water in the pipeline Av Gives rise to a pressure
Ap tăng theo formula:
C
= CAV Ap / g
Where: c = the wave CELERITY (meters per second)
g = the acceleration Due to gravity.
V)
The approximate wave for HDPE pipes celerities are as follows: