Brian
New Member
Posts: 611
|
Post by Brian on Apr 21, 2014 15:09:31 GMT -5
To clarify, when you say thru-hall in this context, your hull is your filter? Yes |
|
|
|
Post by mwardncsu on Apr 21, 2014 15:17:29 GMT -5
If you come in the side, and don't have a standpipe up the middle, then how will the water get to where it will be forced through the filter?
|
|
Brian
New Member
Posts: 611
|
Post by Brian on Apr 21, 2014 15:18:02 GMT -5
To clarify, the height on the inlet of the filter will either be determined via a side entry or using a pipe coming up the middle. I have now decided this will be from the side. The higher this is in the 6" pvc, the less head pressure (Delta between bait tank height and inlet pipe. The less head pressure, the less flow and the greater the chance you starve your pump. No... Assuming the filter is flowing relatively freely, The "head pressure" will always be the difference between the height of the pump and the waterline which should be the same in the tank and the filter... Not possible... Gravity in moving the water from the tank to the filter... The flow will always try to make the water level the same in the tank and the filter. (The water level in both will rise if the filter clogs, but that's because of the air volume which is now displacing the water that should be in the bottom of the filter. The inlet to the filter needs to be below the water level... otherwise nothing will flow. The tradeoff is the lower it is, the less room for the filter below it. |
|
Brian
New Member
Posts: 611
|
Post by Brian on Apr 21, 2014 15:19:56 GMT -5
If you come in the side, and don't have a standpipe up the middle, then how will the water get to where it will be forced through the filter? Now I'm confused... I though he was talking about a gravity feed like a SBTII... But his questions and your answer now sound like the pump is before the filter. |
|
|
|
Post by mwardncsu on Apr 21, 2014 15:25:18 GMT -5
I'm assuming the pump is after the filter, and the filter is gravity fed, but if his input is on the side, and there is not a standpipe for the head pressure from the tank to push the water up to the top of the filter and overflow down, then won't the wont the water just come in the side, and drain down, and now through the filter material - you'll need some type of stand-pipe.
|
|
Brian
New Member
Posts: 611
|
Post by Brian on Apr 21, 2014 15:49:21 GMT -5
you'll need some type of stand-pipe. The stand-pipe is external to the filter in the crayon drawing of what I did on my NauticStar. Assuming by "stand-pipe" you mean the way the water gets from the tank to the top of the filter.  edited to add: The pump is constantly lowering the level of water in the filter and raising the level of water in the tank, so the inlet can be a "standpipe" in the middle, an inlet in the side, whatever, the water will always flow into the filter from the tank. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 21, 2014 15:55:56 GMT -5
If you come in the side, and don't have a standpipe up the middle, then how will the water get to where it will be forced through the filter? Uhhhggghhh. Here is a sketch. Damn words are difficult sometimes.  All I am trying to say is that the height of my gravity fed inlet to the 6" pipe needs to be able to create a flow of greater than 500 gph or my pump will starve. The greater the distance this inlet is from the height of the water column in the bait tank, the greater the flow. The flow has to reach 500 gph to establish equilibrium. The lower this intake is to the pipe, the greater the chance that delta H will overcome 500 gph. Brcarls, are you saying that the flow into the filter will be the same no matter what the delta H is? I don't think this would be correct. Of course there is a maximum flow created by gravity but this can never occur unless you drop water into a vaccuum. Bottom line, if I cant get above 500 gph coming into my filter, my pump will starve...right??? |
|
Brian
New Member
Posts: 611
|
Post by Brian on Apr 21, 2014 15:56:49 GMT -5
And the "head pressure" is irrelevant... The lower the outlet from the tank is located in the tank, the taller the water column is that the headpressure must lift... And the higher it is the less weight of water it must lift, so it's a wash. The same goes for the height of the inlet into the filter, you want it high enough so that your filter material fits below it, but it must be below the waterline (in the tank) otherwise no water will flow since no matter what, X inches of water creating head pressure cannot lift water higher than X inches |
|
Brian
New Member
Posts: 611
|
Post by Brian on Apr 21, 2014 16:00:19 GMT -5
Brcarls, are you saying that the flow into the filter will be the same no matter what the delta H is? I don't think this would be correct. yes (edited to add: assuming you're talking about adjusting the inlet and outlet heights, not adjusting the position of the pump) (edited again to say: also assuming the pump isn't starving all the time which would cause a huge difference in the water level in the tank vs the filter) Also correct, but the volume of water that can flow due to gravity depends on the diameter and length of the pipe and the flow possible through your filter (which decreases as the shad much it up). It does not depend on the inlet or outlet height. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 21, 2014 16:15:56 GMT -5
And the "head pressure" is irrelevant... The lower the outlet from the tank is located in the tank, the taller the water column is that the headpressure must lift... And the higher it is the less weight of water it must lift, so it's a wash. The same goes for the height of the inlet into the filter, you want it high enough so that your filter material fits below it, but it must be below the waterline (in the tank) otherwise no water will flow since no matter what, X inches of water creating head pressure cannot lift water higher than X inches Aha..yes, this is what I was looking for. I was only considering the beer bong principle. As you raise the funnel, the faster the beer flows until it reaches the maximum flow of the pipe. But maybe this isn't correct? I also wasn't considering the effects of water being above the inlet and pushing back. So..then doesn't this mean that I have to find the sweet spot that will allow an equilibrium to be achieved so as the water never gets above the inlet of the filter and the level in the tank is always above the inlet of the filter? In other words, the height of the inlet does matter. If I just stick it right below the desired water level in the bait tank, as the tank empties the inlet will be above the tank and no flow will occur. So finding this sweet spot is my conundrum. |
|
Brian
New Member
Posts: 611
|
Post by Brian on Apr 21, 2014 16:42:52 GMT -5
Aha..yes, this is what I was looking for. I was only considering the beer bong principle. As you raise the funnel, the faster the beer flows until it reaches the maximum flow of the pipe. But maybe this isn't correct? I also wasn't considering the effects of water being above the inlet and pushing back. I think we started with different sets of assumptions Just like men's clothing, there are 2 sizes of pipe, big-enough and not-big-enough. If the pipe is big-enough, then the inlet/outlet position is irrelevant. If it is not-big-enough then the beer bong principle comes into play and there are marginal conditions where the inlet/outlet positions will matter. I think if the pipe is big-enough then it will just work as long as the inlet to the filter is lower than the nominal water level in the tank. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 21, 2014 16:58:02 GMT -5
Aha..yes, this is what I was looking for. I was only considering the beer bong principle. As you raise the funnel, the faster the beer flows until it reaches the maximum flow of the pipe. But maybe this isn't correct? I also wasn't considering the effects of water being above the inlet and pushing back. I think we started with different sets of assumptions Just like men's clothing, there are 2 sizes of pipe, big-enough and not-big-enough. If the pipe is big-enough, then the inlet/outlet position is irrelevant. If it is not-big-enough then the beer bong principle comes into play and there are marginal conditions where the inlet/outlet positions will matter. I think if the pipe is big-enough then it will just work as long as the inlet to the filter is lower than the nominal water level in the tank. I think we are now back on the same page! If I use a 3 inch inlet pipe to the filter, this is almost like dropping water from the sky. It will fall at the same speed no matter how high you drop it. So... to really make sure I don't have to re-glue fittings etc. I think I will use a more than needed size (probably 1.5") inlet pipe to the filter and place a gate valve on it to tame gravity the way I want it. Ideally, I want to keep my water in the filter below my inlet so as to keep more water in my bait tank. My man, this discussion has sealed the deal. Thank you! Yam |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 21, 2014 18:44:37 GMT -5
bilge/recirc - all the same to what I'm thinking - basically a Rule 500 gph pump. Not sure the difference, other than I guess a "recirc" is plumbed with an intake and return and the bilge has the open intake? The advantage of the bilge style is that when they die - and they will - you only have one fitting to change - quicker and easier to do on the water. I always keep a spare pump on-hand on the boat. I finally understand what you are saying. From looking into my bilge, my bilge pump and live well pump are basically the same thing. I never really understood this. So now, the only advantage is quieter operation if I were to place the bilge pump inside the tank. And this is not better than having easy access to the thru-hull pump. I always thought the live well pump would go bad very quick if you ran it dry. I doubt this is the case since a bilge pump can take a good beating without water. Thanks Mward. I'm in an accelerated desire to learn and innovate stage as a result of being converted to a live-bait fisherman. Please be patient for I still have a lot to learn. Yam |
|
BentRod
Global Moderator
Posts: 2,252
|
Post by BentRod on Apr 21, 2014 19:54:35 GMT -5
I didn't read all that, but there are plenty of live well pumps that have a cartridge type replacement so you don't have to replace any of the fittings..just the pump itself.
|
|
