Reply To: Pressure Vs Flow

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SylvanLMP
Participant


In reply to message posted by Harold Kestenholz:
However, to continue the postulation: If the flow rate through a pipe is governed by a restriction at the outlet end of the pipe, removing the restriction can make the flow increase in the pipe even though the pressure drops. This variable is based on where the restriction that governs flow is located. This effect can be seen when the pressure drops as a tap is opened to increase flow.

Thus bumblebees can fly.


Exactly Grass hopper

BUT

Depending on the flow rate required and the available pressure as you cannot supply a 8″ water main with a 2 ” pipe even with a lot of pressure if the 8″ pipe is fully open.

YOU CANNOT compress water so thus you can only get a certain amount of volume in a given sized pipe.

Think about a pump sucking air from a water main Where does this air come from if indeed the pipe s full of water?

Friction losses and head loss (.434) plus the “Force” if taken into consideration would confuse the Frauds in P&H

Here let me give you an example ask an off the Wallfraud to explain the following.

Say you have a pipe 110 ft high and its 8″ diameter ask these P&H non trainables what is the hydrostatic “pressure” at the base ?

Then ask what is the “force” and see what answers you get on a list that is supposed to have “professionals” on here giving basic answers to simple plumbing questions.

The origional question was very valid and a great topic for helpers to learn that rweal plumbing is not a hit and miss application.

The folks dabbling in these fields without a formal education from a real trade schools are just handymen getting over on the public.

A jetter giving 3,000 PSI through a 3/4″ inch hose will also give me 3,000 PSI through an 1/8th inch hose But if I should increase the orifice size of the nozzles my pressure MAY drop but I know my volume would increase.

Pressure drop is not a given on all systems.

As a Master plumber and a Master Fire Suppression piping contractor (NFPA RULES) WE hydrostatically design our systems to keep flow losses to a minimum with the velocity to remain in safe limits.

“Plumbing” one has to know about sanitary,storm and water piping velocities as all of these are different.

Could you imagine taking a P&H guy and asking them to tell you the speed of STEAM for example flying in a vacuum system.

Ask the average P&H bum to tell you how a boiler on a roof 33 Stories works to supply heat to the entire building STEAM ot hydronics or a combination there of.

Harold these so called trades can get as complicated as anyone wants them if they are willing to ask the right questions rather then knocking someone for knowing something.

Every single day I learn something new like the new systems used for fire supression systems or steam operated elevators which I recently saw.

Harold thank you again for one heck of a web site you have created, this site should atleast make the average home owner much more aware of options in design then some of the unemployables out there unlicensed heating folks are dabbling in.

Thank you Harold for a most enjoyable discussion.

Im still learning so please be patient with me.

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