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Power-User

Join Date: Nov 2005
Posts: 116
Good Answers: 7

Greg's Challenge Question 2

06/11/2007 10:59 AM

Your son has just bought a pressure washer to do some work around the house for you. He says that he will only do the work around the house if you can answer his question correctly. So your son then asks you what would happen if there was a leak in the garden hose which is feeding the pressure washer (while it is in use). Will water leak from the hose, or will air leak into the hose from the atmosphere? Can you get your son to do the work by answering the question correctly?

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Power-User
United States - Member - Western Wisconsin

Join Date: Mar 2007
Location: Wisconsin USA
Posts: 305
Good Answers: 25
#1

Re: Greg's Challenge Question 2

06/11/2007 11:15 AM

The garden hose supplies a larger volume than the power washer uses so as long as the leak is small no part of the garden hose should experience negative pressure. If a very large leak like a cut or partially severed hose occurred it would be possible for water to leak out and air to enter.

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Guru

Join Date: Nov 2006
Location: KnoxTN
Posts: 1485
Good Answers: 6
#2

Re: Greg's Challenge Question 2

06/11/2007 11:16 AM

"Will water leak from the hose, or will air leak into the hose from the atmosphere?"

Water will leak FROM the supply hose unless the hose is undersized or the supply valve is not fully open.

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Power-User

Join Date: Dec 2006
Location: South Africa
Posts: 200
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#3

Re: Greg's Challenge Question 2

06/11/2007 1:20 PM

No. My son are trying to get a way out of doing the work and will trick me so that I will have to do it myself.

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Anonymous Poster
#4

Re: Greg's Challenge Question 2

06/12/2007 2:24 AM

Where comes the water from? If it comes from a dwell then it is a risk. In fact the problem is limited to the question how big is the static pressure at the leak place? Is water pressure higher? it flows out

Is air pressure higher ? it will go in and the pump will cavitate.

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Associate

Join Date: Jun 2007
Location: Zaragoza, Spain
Posts: 35
#5

Re: Greg's Challenge Question 2

06/12/2007 4:00 AM

Dear Greg,

1st. It will leak.

2nd. My son (if I had one!!) would probably pierce the hose to avoid the work!! :)

Best regards,

Abel

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Anonymous Poster
#6

Re: Greg's Challenge Question 2

06/12/2007 8:17 AM

There is the pressure washer washer, the hose and , the house. To save time and effort in explaining the various things that could happen and the expense of rigging any gauges to test performance, lets just start the job and see if there are any difficulties.

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Active Contributor

Join Date: Feb 2007
Location: Murfreesboro, Tennessee (near Nashville)
Posts: 24
#7

Re: Greg's Challenge Question 2

06/12/2007 8:40 AM

I know my son(s) pretty well and I would take his question to mean that 1) he has run over the hose with the lawn mower and cut in two - and 2) he is try to use this as an excuse to get out of pressure washing.

If the hose has been cut in two then I would answer his question like this: The half of the hose that is connected to the spigot will discharge water to the atmosphere the half of the hose that is connected to the pressure washer will draw air in from the atmosphere because the pressure washer is a pump.

Now fix the hose and get to work.

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Anonymous Poster
#8

Re: Greg's Challenge Question 2

06/12/2007 10:30 AM

My son would stop wasting time with silly questions and get to work or have a boot in his rear!

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Anonymous Poster
#9
In reply to #8

Re: Greg's Challenge Question 2

06/12/2007 12:26 PM

it is a very modern and progressive educational approach!!!!!!

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Guru
Engineering Fields - Marine Engineering - New Member

Join Date: May 2007
Location: Australia.
Posts: 1642
Good Answers: 81
#10

Re: Greg's Challenge Question 2

06/17/2007 5:21 AM

I quess it may depend on the angle of the leak in the hose, if angled with or across the flow you will get a venturi effect and ingress air, but I'm sure it the boy was faced in the right direction and stopped working the angles he's be a lot better off.

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