Steve,
The Ozzie cricket team conspiracy theory is that Kerry Packer wanted to up the TV ratings so needed the best of the best to drop their bundle to even things up. Who would have watched another rout? What advertiser wouldby air time to watch another three day beating of the old foe?
Good luck with giving up your addiction, theres no looking back when you are successful. Hopefully you will be around for a few more decades as a result.
Geoff
Steve McKenzie <Mechproj@xtra.co.nz> wrote:
Hi Robin
Yes I have been quiet; managing one project too many while trying to
quit smoking is sapping most of my energy.
Plus this forum seems to be keeping itself well occupied by members
squabbling, so theres really little opportunity for constructive
contribution at present. Will contribute a little more when members
decide talking about piping is more interesting than bleating about the
odd silly question and sharp response.
Should still be about the South Island in Nov so give me a call when you
know your itinerary. Think I will be going to be in your neck of the
woods early(ish) next year so I may return the favour.
What on earth have you done to your cricket team?
Cheers
Steve
-----Original Message-----
From: PipingDesign@yahoogroups.com [mailto:PipingDesign@yahoogroups.com]
On Behalf Of Robin Badcock
Sent: Friday, September 02, 2005 6:42 PM
To: PipingDesign@yahoogroups.com
Subject: Re: [PipingDesign] Potable water Piping
Well spoken Steve,
Mean rates have little bearing on hydraulic design other than resource planning. Instantaneous piping flow demands will bring you unstuck every time if not factored in at the start. This is true of the ever aging piping infrastructure we have in our towns and city's as the population density increases and sprawl becomes greater. Lots of booster pump stations on VFD control going in around the joint as a temporary short term band-aid fix to the problem.
I thought you must have exited the group as you have been unusually quiet? I am coming to you fair Island in November; any chance of a catch up and a beer?
Cheers,
Robin
> Yeehah its Chris bashing season again.
>
> Adding to Chris's comments:
>
> True networks are always troublesome things, and expressing demand in
> daily consumption is always a recipe for misunderstanding.
>
> For example, and increase from 45 to 70 TPD sounds like an upgrade at
> a small plant. The nature of the increase and the existing demand
> profile must be known in order to predict the effect on the system.
>
> For example while the daily demand is 45TPD, the peak hourly demand
> could easily be four times this if, say showers at knockoff time are a
> major component of the daily demand. If more showers are installed
> then chances are the peak demand will increase and the hydraulics may
> suffer accordingly. However if a second shift is added then no more
> showers need to be added, and the hydraulics will remain the same
> although the daily demand will be increased. Similarly, if the
> increase in daily demand is due to another cooling tower, then the
> effect on the system hydraulics may be negligible is the system was
> sized for a peak demand well in excess of the average.
>
> Another area in networks which can cause difficulty is the concept of
> residual pressure/head which is the required head at the point of
> discharge or ownership transfer. Suppose the required residual head is
> 30psi and the network system loss is 10 psi. Then the required
> pressure at the (single) network supply node is 40psi Then assuming
> the peak demand increases as the daily, the new required pressure is
> 10 X 2.6 + 30 = 56psi.
>
> With networks it is more important that usual to formulate any
> question clearly. It is essential to know or agree the peak
> instantaneous demand in order to size the pumps and pipes. Daily
> demand is of more interest from an accounting/stockholding
> perspective.
>
>
> Cheers
>
> Steve
>
> -----Original Message-----
> From: PipingDesign@yahoogroups.com
> [mailto:PipingDesign@yahoogroups.com]
> On Behalf Of Christopher Wright
> Sent: Tuesday, August 30, 2005 4:04 PM
> To: PipingDesign@yahoogroups.com
> Subject: Re: [PipingDesign] Potable water Piping
>
>
> > If a present system is warking on 40 psi and
> > fulfilling the requirement of 45 ton/day and if the requirement goes
> > to 70 ton per day than what is the critaria of hydraulics of potable
> > water netwark?
> In general the pressure drop across a network goes as the square of
> the flow rate. If you jack up the flow rate by a factor of 70/45 = 1.6
> the upstream pressure needed to get all that water through will
> increase by a factor of 2.6 if you make no mods to the system. The
> flow velocity (which affects associated response, like water hammer)
> goes up by the 1.6 factor. You can start checking the system part by
> part to see what changes you need to make to withstand the new
> pressure and handle the new velocity. Christopher Wright P.E. |"They
> couldn't hit an elephant at
> chrisw@skypoint.com | this distance" (last words of Gen.
> .......................................| John Sedgwick, Spotsylvania
> 1864)
> http://www.skypoint.com/~chrisw/
>
>
>
>
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[Non-text portions of this message have been removed] Received on Fri Sep 02 18:33:00 2005
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