Need help with a drip plate

[vaypourus]

I'm at a point where I'm stuck with my DIY W/D sump design.

I have a drip plate that is approximately 2 feet long by approximately 12 inches wide. My flow will be approximately 900-1000 GPH over the plate.

I am not sure what size holes to drill, and how closely together they need to be drilled.

Anyone have any input?

 

[TStephens]

Try and simulate the size and layout of the holes to pegboard. Hope this helps.

 

[black056mtc]

drill the holes 1" aparts about the size of a tooth pick or smaller, you can always go larger if needed but can't go smaller keep that in mind.

 

[CHOMPERS]

Something tells me you want the nerdy approach...

But first just to be in the spirit of the thread, lets take the hap-hazard approach. Pick a drill bit at random. One that you like. Or one that just stands out from the rest. Just make sure it is sharp.

On the side, it should have the size (diameter). You'll need that later.

So lets jump over to the flow for a minute (800-1000 gph). Using the relationship that a one inch pipe will flow 600 gph, calculate the size that you will need to handle your max flow. Keep in mind that the area of a circle is that 'pie are square' thing. (A= pi x r^2)

Next, using the drill size, calculate it's cross sectional area. Now divide the cross sectional area of the pipe size needed for your flow by the cross sectional area of your drill bit.

That is how many holes you will need to drill using your bit.

 

[vaypourus]

Something tells me you want the nerdy approach...

lol I like you. We are friends now.

I actually considered calculating the flow using a simple area measurement, but then I remember seeing a demonstration of flow through a shower head years ago in my Fluids class. We determined the expected flow based on some Bernoulli calculations. When the water was not pumped through the head but allowed to flow with just gravity alone, we ended up seeing actual numbers that were considerably lower due to water friction, adhesion, cohesion, and all that other weird stuff water tends to do.

While I'm sure some basic calculations would probably work well enough I don't want to have to go and buy another sheet of 1/8" acrylic. I don't want is to overflow my plate because the holes are too small, or worse, not get any water reaching the far side of the drip plate because the holes are too big. I'm not a big "trial & error" kind of guy.

I was really just hoping somebody else would have some experience with what works well in a real world situation. So far though, I'm seeing a wide variety of answers...

 

[Pharaoh]

For the basic approach, most people will start with a 1/8" bit and drill a hole every inch. In order to get a perfect spread, you would have to calculate it as Chompers said.

 

[kallmond]

Sometimes its best to use your gut. Sometimes math is better. I think in this case calculating the friction coefficient of plexiglass vs cohesion properties of water at a given kH, and then calculating flow rate based on overflow diameter is way more work than just drilling a bunch of 1/8 holes an inch apart and watching the water to see if you need more.

 

[CHOMPERS]

lol I like you. We are friends now.

LOL, you're now an honorary member of the Nerd Herd.

You'll need 107 holes if you use a 1/8" drill bit. But you can always round it up to 110 to keep it symmetrical. If it is not going to have raised edges (a drip plate rather than a tray), drill an extra set of holes around the outside of the 110. If you haven't peeled the paper off yet, draw a grid on it and drill at all of the intersections. It will give it a very professional look. If the paper is already off, use some masking tape.

If you remember how to calculate the error in the shower head problem, I could use your help in the sticky thread for pipe sizing. The numbers need tweeking (but it hasn't been a problem yet).

 

[CHOMPERS]

cohesion properties of water at a given kH

My first reaction was "nuh uh", but then I remembered that the Alkalinity makes the water "slippery". The hardness and pH also play a part, but I don't remember which way each affects the other.

Anyone have further input or ideas?

 

[vaypourus]

LOL, you're now an honorary member of the Nerd Herd.

Sweet. Where do I sign?

If you remember how to calculate the error in the shower head problem, I could use your help in the sticky thread for pipe sizing. The numbers need tweeking (but it hasn't been a problem yet).

Honestly I don't. I took fluids in 2002, and decided to go into computers/system engineering rather than mechanical engineering after that semester. I haven't touched it since then. This is part of the reason I don't want to do all those calculations...that is a lot of digging and relearning. lol

I'll take a peek at it though...I can also consult my younger brother. He's a rocket engineer @ Embry-Riddle and is probably a bit more up to date with fluid behavior than I am