Re: copper pipe size in treatment system
Posted by Gary Slusser on June 06, 2004 at 00:03:03:
In response to Re: copper pipe size in treatment system
: : Gary
: : Quality Water Associates

: Hi Gary,

: RE:We water treatment guys use flow controls when needed, not undersized tubing and for a solution feeder, there is no need to control the flow.

: Many times rather then go for a mechanical device like "flow control devices" we can do it math mathematically.

: For example if a filter has a rating of no more then 20 GPM to remove sediment all one would have to do is find the in coming pressure.

: Lets assume that the available pressure is 65 PSI and we are running 3/4 lines, the volume flowing would hover around 39.37 GPM thus rendering the filter useless.

: Now if the installer used 1/2" prior to going into this filter the VOLUME flowing through this piping would be 17.5 GPM still well with in the filters capacity to remove sediment without causing undo turbulence.

: This is especially true on acid crock systems, like a floor drain in a battery room or in a laboratory where this acidic waste has to be controlled prior to entering the neutralizing tank.

: Too fast and the marble chips will not have time to do their job and not every installation has room to have a holding tank.

: Thus we have to depend on piping sized to reduce volume rather then figuring baffles or mechanical devices that are prone to failure

:
: Look at the common grease trap for example. Flow rates are critical, even in boilers with hot water tankless coil applications one uses piping of various sizes to get the desired effect.

: Older heating steam and hydronics depended on piping being increased or decreased depending on what the condition needed.

: Hey its just another train of thought

Sylvan, here's what he said.: I have a clorine system install and was looking over the piping and noticed something kind of interesting, all the copperin the system is 3/4 in but in between the settling tanks and the carbon filter I have a 1/2 test tap. There is about a 1 foot section that is 1/2 in the middle of all the 3/4 pipe. Will this effect anything like pressure or water flow. I would think that the installer would have used 3/4 with a T and gone 1/2 off the T to the test tap. Next month I am having all the old copper pipe replaced in the house and I wonder if I should have them replace this little section of mismatched pipe.

If the carbon filter isn't capable of treating his flow rate because the SFR (service flow rate) of the filter is too small for the water system it is installed on, then it's misapplied equipment. As I said we dont use flow cntrols normally, we, well most of us, size the equipment properly to begin with. But as you demonstrate, his flow will be reduced by the use of the foot of 1/2" and the pressure loss of the tee used for the sample port faucet. And then the reduced flow due the the 1/2" will be magnified by the (too small/) filter.

Also, it's my understanding that a flow control if needed is installed on the outlet of the filter; especially if the filter is a backwashed type and not upflow because the gpm required for proper backwash rates is usually higher than the SFR of the filter although he has a carbon filter where it probably wouldn't be. Actually all backwashed or regenerated filters (softeners too) have a (normally built in) drain line flow control.

BTW, although saying this will undoubtly cause me to... I've installed hundreds of (Dole) flow controls with residential and commercial UV lights over the years and so far, not a one has caused a problem to my knowledge.

Gary
Quality Water Associates


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