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Naja02

Active Member

1

Wednesday, February 15th 2006, 7:00pm

Nelson Valves....???

Wondering what the quality of Nelson valves are...???

I realize that Hunter Valves are probably much better quality, but I am looking for specific features that I have found in Nelson's, but not Hunter's--Very Low GPM (0.2) and Low Operating Psi (10psi). This is Not for a lawn/Sprinkler application, but Your Knowledge and Assistance would be Greatly Appreciated!!!

Many Thanx!

Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

2

Thursday, February 16th 2006, 5:24am

What is the application?

Naja02

Active Member

3

Thursday, February 16th 2006, 9:14am

Its an InLine Automatic Water Changing System for an Aquarium.

Here is a Link to the Thread on another Forum:

http://www.plantedtank.net/forums/diy/21414-bulkhead-line-replenishment-snag-4.html

Its the Exchange Between Naja002-(myself) and Scolley. The First Pertinent post is mine (Naja002) about mid way down the page. Its Probably a 10 min read.

Any Thoughts, Tips, Pointer would be Great!

I am assuming now that with "Start Time Stacking" Dual Valves set to open/close at the exact same time would require Dual Controllers...? Any Thoughts on that or any work arounds...?

Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

4

Thursday, February 16th 2006, 12:00pm

I've read through the thread. Forget the sprinkler valves, and work with peristaltic pumps, if you want the most positive operation and control. Sprinkler valves need too much upstream pressure for that sort of application.

Naja02

Active Member

5

Thursday, February 16th 2006, 1:15pm

I'm not sure that I understand:

The household Pressure would go to the valves. Then another pressure regulator would reduce the Pressure AFTER the valves. So, the only question would be Flow. I have been surfing valves and have seen them available with working psi as low as 5 and normally as low as 10psi. Also, with flow rates (3/4") as low as 0.1GPM and 0.2GPM.

These are all acceptable for this application--even if those numbers are Theorectical lows claimed by the manufacturer.

Also, these valves are used for misting and drip irrigation systems where the flow is low, regardless of whether or not the pressure is high. The actual output quantity is still low.

Also, there is at least 1 irrigation controller that permits the cycle time to be set buy 1 second increments and states the it will operate 2 valves at once. It is a 6 Station Controller.

Can You tell me where I am seeing this wrong...???

Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

6

Friday, February 17th 2006, 3:41am

The whole line of thought is kind of wack. The thread is about trying to solve a problem created only because the original poster created a set of unrealistic conditions. If you do want to pursue the thread, forget sprinkler diaphragm valves, and go for 'direct acting' solenoid valves. They are of zero interest to the lawn sprinkler trade, so you have to buy them somewhere else.

Naja02

Active Member

7

Friday, February 17th 2006, 10:04pm

I appreciate Your input here, but You are not telling me WHY Sprinkler Components will not work....

I realize that there are better and much more Expensive ways of doing this, but that never was the question...

Experiment #2 in my last post on the other thread shows the amount of upstream pressure NEEDED=Gravity. And Scolley's drainage setup would probably supply a little bit more pressure than my experiment--all the better.

For the InFlow back into the tank--plenty of pressure is supplied by the household water supply. Too much in fact. So, it would need to be reduced by the second water pressure regulator.

Upstream pressure doesn't need to be Great and that is shown by my Experiment (#2) and the various manufacturer's Specs (5-10 psi). If I had a water pressure regulator laying around--I would use the components that I have and do experiments on the upstream/inflow. But I don't.

This is simply about Control of Flow. And as I'm sure You know the Valves are just gates that start and stop the flow and the Controller restricts the timeframe of the flow.

So, basically, I need some understanding as to WHY the sprinkler components will not work--otherwise, what I know, believe and have experienced--still lead me to believe that they will.

I value Your Input, but You're really not answering the question in a way that is beneficial to understanding WHY these components will not work.

Any Insight?


Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

8

Saturday, February 18th 2006, 4:56am

I kind of feel like a parent telling his child that Santa Claus isn't real. Suffice it to say that lawn sprinkler diaphragm valves are <b>not</b> the simple gates you picture them as. They have requirements of flow and/or pressure that don't generally fall within the parameters of your project. Looking at a manufacturer's chart can be misleading, especially at the margins of performance. There are numerous contraptions assembled from devices that should work together and perform a function, but fail to do so because of a lack of understanding of the devices' individual or combined constraints.

A direct-acting solenoid valve is just that. Coil is energized. Plunger lifts. Fluid flows through exposed orifice. No diaphragms. They have their own constraints, based on operating pressure, solenoid power, and fluid viscosity. While I said these kinds of valves aren't used for lawn sprinklers, they are found on the very-large valves that you see on pipes larger than three inches in diameter. Valves of this size employ exposed &frac14;" control tubing to route water from one valve area to another, sometimes through equally small direct-acting solenoid valves, pressure regulators, manual needle valves, and similar.

Wet_Boots

Supreme Member

Posts: 4,060

Location: Metro NYC

9

Sunday, February 19th 2006, 9:19am

One more thing about the aquarium idea. Does the water need any treatment before it comes in contact with the fish? Can you depend on the water supply containing a specific level of (for example) chloramines needing to be neutralized? It seems that setting dosing levels on an assumed level of neutralizing will fall afoul of the treatment plant having some hiccup that puts extra chemicals in the water. I live near a treatment plant, and I know there are variations in the chlorine scent the water can have.

By the way, I didn't want to maintain that there was no chance whatsoever for a valve to work at very low flows. There are some expensive special-design ($$$) diaphragm valves that have no minimum flow requirement. (they also vent water when they open, so indoor use is unlikely) I just wanted to make you aware that you shouldn't stake everything on the numbers you might see on performance charts. Lots of people can read some chart that says a sprinkler head has a maximum distance of 42 feet at 50 psi, and set up a sprinkler system that depends on that performance, whereupon they become very unhappy with the unexpected dead areas on their lawn, that should be getting watered, "according to the book."

Naja02

Active Member

10

Sunday, February 19th 2006, 12:25pm

Hi Wet Boots,

I fully understand what You are saying and You are Correct. I believe that this sytem will need 10 psi or more for inflow--and that is why I was asking about the Nelsons. They offer 5 psi which keeps me a little further away from the "Manufacturer's Claim". Meaning that if it needs 10, 12, or 15 psi then I am further away from the minimum claim of 5 psi than with the Hunters--10 psi minimum. I realize that Hunter is a quality product in this biz, but I was looking to hedge my bet with the Nelson 5 psi-If they are reliable long-term.

The Unrealistic conditions of this are conditions that Scolley had set for himself long before this Auto Water Changing System came into play. And So far he has done very well at accomplishing that goal.

With Scolley's desire of only a 1 gal. water change/cycle--he <u>Probably</u> doesn't even need to be concerned with treating the water. But generally most water depts add chlorine and chlorimines and they do need to be treated for. The problem is that we just dose what we are supposed to--because there is no way for us to know if there is a spike. Its not a Problem at all that I am aware of...

The peristaltic pumps are a Great idea, but they throw the cost way out of range. The Direct Action Valves are another Great idea, but it then comes down to what route the individual wants to take and how much they are willing to spend. The Low Cost of the Sprinkler/Drip irrigation valves is what makes them so attractive--at least initially. And that low cost also makes them attractive because dual valves can be used on each the intake and outflow for backup safety.

I like the Direct Action valves, but I, personally, don't have a NEED or strong desire for this system, so my interest is more academic--Problem-solving on behalf of another. I really enjoy this kind of stuff. So, the Direct Action valves become a bit cost Prohibitive for me, but Scolley, or someone else, may chose to go that route and find them to be a Great bargin. Spend more on the Valves and save on the controller.....

All and All: I Appreciate Your Honesty and forthrightness more than You probably know. The links here are in the other thread on the other forum. I will bounce back in the future and let You know what's been treid/accomplished.

Many Thanx!

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