Sea swirl closed loop completed
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But, this is not a "closed loop system." So you do have to figure head pressure for the return from the floor to the tank.
<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by esmithiii:
<strong>Remember that for a closed loop system, the only thing that contributes to head pressure is the length and diameter of the tubing and the number of bends. Height of tank does not contribute to head loss as it does when you are pumping from a sump.
E</strong><hr></blockquote>
<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by esmithiii:
<strong>Remember that for a closed loop system, the only thing that contributes to head pressure is the length and diameter of the tubing and the number of bends. Height of tank does not contribute to head loss as it does when you are pumping from a sump.
E</strong><hr></blockquote>
Actually it is a closed loop. Since the line coming into the pump is pressurized, by definition it is closed loop. You do not need to calculate head pressure loss due to the height of the tank for this system.
"closed loop" means that the pump sucks water directly from the tank and returns it directly without passing through an intermediate resevoir. It doesn't mean that the whole tubing is one close circuit!
In a system that uses a sump, the line coming into the pump from the sump is not pressurized.
The weight of the water in the tank above the pump has potential energy since it is above the pump. The potential energy difference is zero in a closed loop system since the height that the water travels downward is the same height that it has to overcome going upwards. The net is zero. Read the car analogy again and you will see what I am talking about. In a situation where you have a sump, the energy of the water moving downwards from the tank into the sump is lost before it enters the return pump.
Interestingly enough as long as the intake and the exhaust of the closed loop system are both under the surface of the water, it does not matter where the intake or exhaust are. The potential energy of the water entering the downward section of tubing is measured based on the height of the surface of the water, not the height of the intake nozzle.
Ernie
"closed loop" means that the pump sucks water directly from the tank and returns it directly without passing through an intermediate resevoir. It doesn't mean that the whole tubing is one close circuit!
In a system that uses a sump, the line coming into the pump from the sump is not pressurized.
The weight of the water in the tank above the pump has potential energy since it is above the pump. The potential energy difference is zero in a closed loop system since the height that the water travels downward is the same height that it has to overcome going upwards. The net is zero. Read the car analogy again and you will see what I am talking about. In a situation where you have a sump, the energy of the water moving downwards from the tank into the sump is lost before it enters the return pump.
Interestingly enough as long as the intake and the exhaust of the closed loop system are both under the surface of the water, it does not matter where the intake or exhaust are. The potential energy of the water entering the downward section of tubing is measured based on the height of the surface of the water, not the height of the intake nozzle.
Ernie
Interesting arguement. What type of heat do you have in your house. I have base board hot water, and depending on the type of house you have, ranch or anytype with a 2nd floor, the higher up the water has to go, you have to get a bigger pump due to increased head pressure.
You have to figure head pressure for each 90 or 45 as well as the head pressure for each foot of a horizontal run. Depending on the type of pipe you have it will add head pressure to it. Well with this example we are talking about a true closed system, not an open system like you talk about.
A closed system will have an equal liquid pressure on either side of the pump, your closed system will not since it flows into a tank. A closed loop is just like the name, closed. Then I would agree with your statement more. We in this hobby incorectly call a circulation loop a closed loop.
Take care.
[ December 11, 2001: Message edited by: NJMike ]</p>
You have to figure head pressure for each 90 or 45 as well as the head pressure for each foot of a horizontal run. Depending on the type of pipe you have it will add head pressure to it. Well with this example we are talking about a true closed system, not an open system like you talk about.
A closed system will have an equal liquid pressure on either side of the pump, your closed system will not since it flows into a tank. A closed loop is just like the name, closed. Then I would agree with your statement more. We in this hobby incorectly call a circulation loop a closed loop.
Take care.
[ December 11, 2001: Message edited by: NJMike ]</p>
Mike,
I know the gun laws are different in NJ, but I doubt the laws of physics are any different there than they are here
It is not an argument, but fact. Do this:
1. Get four 5 gal. buckets, two ladders,one 8' section of 1/2" inside diameter tubing and one 15' section.
2. Fill two buckets with water. Place each on the top step of each ladder. Place both empty buckets on the floor.
3. On the short section of tubing, place one end in the first full bucket and the other end in the first empty bucket.
4. On the long tubing, place one end in the second full bucket loop it to the floor then up and over the second step from the top then back down into the second empty bucket.
5. Now you and a friend start a siphon on each tube simultaneously.
6. Which bucket will fill up first? They will fill at almost the same time. The only difference is due to the LENGTH of the longer tube, not the fact that the water has to go down, then up then down again!
The rate the water will flow is directly proportional to the square of the difference in heights of the top bucket and the bottom bucket. In the case of a "Closed Circulation loop" as you call it the difference is ZERO since the surface of the water is constant and the line to the pump is closed.
Think of it this way: The inlet pressure going to the pump depends on the difference between the height of the tank and the height of the pump. This pressure is POSITIVE, or in other words, it will "help" the pump out. The pressure the pump has to overcome to rise from the pump to the tank is NEGATIVE, or in other words it works against the pump. Add the two and you come out with zero no matter where the pump is placed. It could be 6" or it could be 60", it doesn't matter.
<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote
You are correct there.
Now in your house example, here is the fallacy:
There is a fixed pressure coming in from the water main to your water heater. This pressure is fixed, and lets say it is positive as in my example above. Let's suppose that your water heater is at ground level. The outlet pressure at the basement will be greater than the pressure on the ground floor, and greater still than the pressure on the second floor (one floor above the water heater.) This is an entirely different situation than the "closed circulation loop" mentioned above.
If you still don't believe me, call any pump manufacturer and they will confirm what I am saying.
Ernie
I know the gun laws are different in NJ, but I doubt the laws of physics are any different there than they are here
It is not an argument, but fact. Do this:
1. Get four 5 gal. buckets, two ladders,one 8' section of 1/2" inside diameter tubing and one 15' section.
2. Fill two buckets with water. Place each on the top step of each ladder. Place both empty buckets on the floor.
3. On the short section of tubing, place one end in the first full bucket and the other end in the first empty bucket.
4. On the long tubing, place one end in the second full bucket loop it to the floor then up and over the second step from the top then back down into the second empty bucket.
5. Now you and a friend start a siphon on each tube simultaneously.
6. Which bucket will fill up first? They will fill at almost the same time. The only difference is due to the LENGTH of the longer tube, not the fact that the water has to go down, then up then down again!
The rate the water will flow is directly proportional to the square of the difference in heights of the top bucket and the bottom bucket. In the case of a "Closed Circulation loop" as you call it the difference is ZERO since the surface of the water is constant and the line to the pump is closed.
Think of it this way: The inlet pressure going to the pump depends on the difference between the height of the tank and the height of the pump. This pressure is POSITIVE, or in other words, it will "help" the pump out. The pressure the pump has to overcome to rise from the pump to the tank is NEGATIVE, or in other words it works against the pump. Add the two and you come out with zero no matter where the pump is placed. It could be 6" or it could be 60", it doesn't matter.
<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote
You are correct there.
Now in your house example, here is the fallacy:
There is a fixed pressure coming in from the water main to your water heater. This pressure is fixed, and lets say it is positive as in my example above. Let's suppose that your water heater is at ground level. The outlet pressure at the basement will be greater than the pressure on the ground floor, and greater still than the pressure on the second floor (one floor above the water heater.) This is an entirely different situation than the "closed circulation loop" mentioned above.
If you still don't believe me, call any pump manufacturer and they will confirm what I am saying.
Ernie
Yea, we here in Jersey do things different. I also took my college physics in Mass, so that can be two states.
I called a pump maker kinda. It was for a canister filter, it's a closed system according to you.I think it is a good model based on your "closed loop." I was given two different MAX HEAD measurements on it. One with filter media, the other empty. If it is not a concern like you said, then why do they have the pump rated for max head.
Seems like they are on my side.
Hmm, I guess things really must different here in NJ. To us, base board hot water is what we use to heat the house in the winter. I was not talking about a water heater.
Take care.
[ December 11, 2001: Message edited by: NJMike ]</p>
I called a pump maker kinda. It was for a canister filter, it's a closed system according to you.I think it is a good model based on your "closed loop." I was given two different MAX HEAD measurements on it. One with filter media, the other empty. If it is not a concern like you said, then why do they have the pump rated for max head.
Seems like they are on my side.
Hmm, I guess things really must different here in NJ. To us, base board hot water is what we use to heat the house in the winter. I was not talking about a water heater.
Take care.
[ December 11, 2001: Message edited by: NJMike ]</p>
actualy I live in jersey and esmithiii is still right....lol. but to me a good way to describe it is like this: water seeks its own level as we all know. take a single piece of say 1 inch hose and loop it from the tank to the floor and back. start a siphon and holding the other end above the level of the tank. note the time it takes for the water to reach level....this is due to the friction created by the tube. now do the same with a piece of airline tubing and note it will take longer becouse a more narrow tube will create more friction.
the amount of head is not zero but close to it. only the friction of the tube and any elbows or bends will create head in this loop.
the in the house example keep in mind that radiators create alot of friction since the water is actualy making alot of bends through narrow pasages within them. and your pipes also make alot of bends both going from the pumps and returning to them creating even more friction ...therefore more head.
hope this simple explenation helps.
Bob
the amount of head is not zero but close to it. only the friction of the tube and any elbows or bends will create head in this loop.
the in the house example keep in mind that radiators create alot of friction since the water is actualy making alot of bends through narrow pasages within them. and your pipes also make alot of bends both going from the pumps and returning to them creating even more friction ...therefore more head.
hope this simple explenation helps.
Bob
A question to all you closed loop users. I am planning for a new big tank (78"x32"x36"high). All of my sump return lines will be directed out through the back of the rockwork. I want to add a closed loop using a large Iwaki pump and 2 SeaSwirls for upper tank circulation. Any suggestions on pump and SeaSwirl size??? I was thinking an MD70 and 2x 1" SeaSwirls. Too big?? Too small??
What you are calling a closed loop is far from a closed loop.
A C/L hydraulic system is just what it's called all pressure being equal. Like recirculating Hot water line. It just recirculates the water no pressure diffrence.
But even then you have hydrostatic pressure to deal with. All you are refering to is say a Cannister filter.
When the water enters a tank under pressure i.e a pump and it's flowing back to the pump from that tank head pressure and siphoen and suction caused by the pump There is a pressure diffrence.
Its called Hydrokientics and even a variable of a 1/2 of a degree of water temp is also added to and has an effect on the the pressure diffrence.
Look at a cannister filter like a fluval? They are rated in Head pressure.
Now that some free education it took yrs to learn. So I hope you guys do not move liquids or gases for a living? Mickeyd said that.
A C/L hydraulic system is just what it's called all pressure being equal. Like recirculating Hot water line. It just recirculates the water no pressure diffrence.
But even then you have hydrostatic pressure to deal with. All you are refering to is say a Cannister filter.
When the water enters a tank under pressure i.e a pump and it's flowing back to the pump from that tank head pressure and siphoen and suction caused by the pump There is a pressure diffrence.
Its called Hydrokientics and even a variable of a 1/2 of a degree of water temp is also added to and has an effect on the the pressure diffrence.
Look at a cannister filter like a fluval? They are rated in Head pressure.
Now that some free education it took yrs to learn. So I hope you guys do not move liquids or gases for a living? Mickeyd said that.
The reason they state head pressure is due to the fact that bends, tubing diameter and T's cause head pressure loss because of friction. Usually tubing used for canister filters is relatively small. Keep in mind that the pressure loss is directly proportional to the length of tubing, and number of bends and inversly proportional to the square of the diameter of the tubing.
MickeyD: Not sure what you mean; maybe trying complete sentences would help get your point across.
And as a matter of fact, I am an industrial engineer, and I often work with equipment that use hydraulic and pneumatic components.
Ernie
MickeyD: Not sure what you mean; maybe trying complete sentences would help get your point across.
Ernie
One more thing: the canister filter has different head ratings for with media and for without because of the friction caused by the media. The media acts as a big filter. Take a piece of heavy cloth and blow through it. Feel the resistance? Same concept when you put media in the canister.
Ernie
Ernie
Hmm, guess the manufacture of the canister filter better email you and correct his product specs.
I asked them straight out, empty cannister, both tubes in a tank, straight runs. Does head pressure effect your pump. They said yes. They gave me the max heads I talked about. Maybe I just don't understand, can you explain to me why they would say this? I understand why the two different head pressures for with/without media.
I must be missing something. I understand your examples with the ladders and all.
As soon as the water goes into the pump and it comes out at a different pressure, if so, you get some head pressure on that side of the pump.
Take care
I asked them straight out, empty cannister, both tubes in a tank, straight runs. Does head pressure effect your pump. They said yes. They gave me the max heads I talked about. Maybe I just don't understand, can you explain to me why they would say this? I understand why the two different head pressures for with/without media.
I must be missing something. I understand your examples with the ladders and all.
As soon as the water goes into the pump and it comes out at a different pressure, if so, you get some head pressure on that side of the pump.
Take care
OK, I think I see the confusion. Head Pressure loss is a way of calculating based on a set of parameters how much output (volume per time) a given pump will produce. There are several things that affect head pressure:
1. Total lenght of tubing (intake and exhaust)
2. Bends and T's
3. Diamter of tubing used
4. Water temperature (mostly negligible in our case)
5. Anything that might cause additional friction: screens, filters, ball valves, my bio-wheel on my freshwater tank, etc.
6. Vertical distance the pump must overcome
In the case of a canister filter, only items 1-5 add to head pressure.
Ernie
[ December 11, 2001: Message edited by: esmithiii ]</p>
1. Total lenght of tubing (intake and exhaust)
2. Bends and T's
3. Diamter of tubing used
4. Water temperature (mostly negligible in our case)
5. Anything that might cause additional friction: screens, filters, ball valves, my bio-wheel on my freshwater tank, etc.
6. Vertical distance the pump must overcome
In the case of a canister filter, only items 1-5 add to head pressure.
Ernie
[ December 11, 2001: Message edited by: esmithiii ]</p>
<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by esmithiii:
<strong>OK, 6. Vertical distance the pump must overcome
</strong><hr></blockquote>
This person said they have 4 ft of head. The pump is located on the ground 4 feet below the bulk heads.
You also said before "Height of tank does not contribute to head loss as it does when you are pumping from a sump"
Ernie what gives? He as a circluation loop, with the pump sitting 4 ft below. You stated above that Vertical distance will increase head pressure, which I agree with. But you also say a closed loop it would not.
If the pump was on the same horizontal plane as the bulk heads I would not be writing all this, but it's below.
Let me ask you this, I have a tank on the 50th floor of a building. Both intake and output are under tank water. The pump is on the first floor, do I have to worry about head pressure.
Take care.
P.S. My Mom calls me a thick headed Irishman.
<strong>OK, 6. Vertical distance the pump must overcome
</strong><hr></blockquote>
This person said they have 4 ft of head. The pump is located on the ground 4 feet below the bulk heads.
You also said before "Height of tank does not contribute to head loss as it does when you are pumping from a sump"
Ernie what gives? He as a circluation loop, with the pump sitting 4 ft below. You stated above that Vertical distance will increase head pressure, which I agree with. But you also say a closed loop it would not.
If the pump was on the same horizontal plane as the bulk heads I would not be writing all this, but it's below.
Let me ask you this, I have a tank on the 50th floor of a building. Both intake and output are under tank water. The pump is on the first floor, do I have to worry about head pressure.
Take care.
P.S. My Mom calls me a thick headed Irishman.
ONCE AGAIN THE DOWNWARD MOVEMENT OF THE WATER IN THE INTAKE TO THE PUMP CANCELS OUT THE VERTICAL HEIGHT IN A CLOSED CIRCULATION LOOP!
In my message above, I said that only items 1-5 contribute to pressure loss in a closed loop system (#6 being the vertical height which is not applicable in this case)
The calculation of 4' head pressure is wrong. It is more like .5' head pressure.
To answer your question about the building, yes. There would be head pressure. Let's suppose each floor is 10', then the total length of tubing is 50 * 10' * 2 = 1000', if there is 10 90 degree elbows and the pipe is 2" inside diameter, the total head loss is 12'.
Here is an interesting calculator:
Head Loss Calculator
Ernie
In my message above, I said that only items 1-5 contribute to pressure loss in a closed loop system (#6 being the vertical height which is not applicable in this case)
The calculation of 4' head pressure is wrong. It is more like .5' head pressure.
To answer your question about the building, yes. There would be head pressure. Let's suppose each floor is 10', then the total length of tubing is 50 * 10' * 2 = 1000', if there is 10 90 degree elbows and the pipe is 2" inside diameter, the total head loss is 12'.
Here is an interesting calculator:
Head Loss Calculator
Ernie
Ok, well I looked at the original post. This is what I am taking as known. Two bulk heads in the tank, one to the pump and one to return water from the pump. The pump is 4 feet below the tank.
I am assuming that the pump is rated for 1000 GPH. I only have one 90 elbow in it to turn back into the tank. I'm using 1" pipe.
Here is what the calculator gave me back.
Using the following input parameters
Friction Factor = 0.17
Vertical Length = 4
Horizontal Length = 0
Pipe Diameter = 1
Flow Rate = 1000
90° Elbows = 1
45° Elbows = 0
Head losses are calculated as
Frictional head loss is 7.25 foot head or 3.13 psi.
Elevation head loss is 4 foot head or 1.73 psi.
Total head loss is 11.25 foot head or 4.86 psi.
Looks like head loss is 11.25 ft.
Going back to your post, I asked about a systems that as I understand by your post is a closed system.
You state "ONCE AGAIN THE DOWNWARD MOVEMENT OF THE WATER IN THE INTAKE TO THE PUMP CANCELS OUT THE VERTICAL HEIGHT IN A CLOSED CIRCULATION LOOP!"
Ok, then I don't have any head pressure just like the person who started this. Buit now I'm really confused, you then state "To answer your question about the building, yes. There would be head pressure. Let's suppose each floor is 10', then the total length of tubing is 50 * 10' * 2 = 1000', if there is 10 90 degree elbows and the pipe is 2" inside diameter, the total head loss is 12'."
Well, I give up. Let this dog go to bed. As far as the calculator goes there is head pressure, sounds like what I have been saying
Take care.
[ December 11, 2001: Message edited by: NJMike ]</p>
I am assuming that the pump is rated for 1000 GPH. I only have one 90 elbow in it to turn back into the tank. I'm using 1" pipe.
Here is what the calculator gave me back.
Using the following input parameters
Friction Factor = 0.17
Vertical Length = 4
Horizontal Length = 0
Pipe Diameter = 1
Flow Rate = 1000
90° Elbows = 1
45° Elbows = 0
Head losses are calculated as
Frictional head loss is 7.25 foot head or 3.13 psi.
Elevation head loss is 4 foot head or 1.73 psi.
Total head loss is 11.25 foot head or 4.86 psi.
Looks like head loss is 11.25 ft.
Going back to your post, I asked about a systems that as I understand by your post is a closed system.
You state "ONCE AGAIN THE DOWNWARD MOVEMENT OF THE WATER IN THE INTAKE TO THE PUMP CANCELS OUT THE VERTICAL HEIGHT IN A CLOSED CIRCULATION LOOP!"
Ok, then I don't have any head pressure just like the person who started this. Buit now I'm really confused, you then state "To answer your question about the building, yes. There would be head pressure. Let's suppose each floor is 10', then the total length of tubing is 50 * 10' * 2 = 1000', if there is 10 90 degree elbows and the pipe is 2" inside diameter, the total head loss is 12'."
Well, I give up. Let this dog go to bed. As far as the calculator goes there is head pressure, sounds like what I have been saying
Take care.
[ December 11, 2001: Message edited by: NJMike ]</p>
Once again, You have to put the vertical as zero for reasons previously stated.
This is the data you should put
Friction Factor = 0.17
Vertical Length = 0
Horizontal Length = 10 (4 down, 4 up and 2 out to the sea swirl)
Pipe Diameter = 2
Flow Rate = 1000
90° Elbows = 6
45° Elbows = 0
Frictional head loss is 0.33 foot head or 0.14 psi.
Elevation head loss is 0 foot head or 0 psi.
Total head loss is 0.33 foot head or 0.14 psi.
Here is the thing you have to remember: Head loss exists for many reasons, the only one that counts here is friction.
The head loss in your building example is due to friction loss only. Plug in the numbers in the calculator and it will give you about 12' head.
Ernie
Ernie
This is the data you should put
Friction Factor = 0.17
Vertical Length = 0
Horizontal Length = 10 (4 down, 4 up and 2 out to the sea swirl)
Pipe Diameter = 2
Flow Rate = 1000
90° Elbows = 6
45° Elbows = 0
Frictional head loss is 0.33 foot head or 0.14 psi.
Elevation head loss is 0 foot head or 0 psi.
Total head loss is 0.33 foot head or 0.14 psi.
Here is the thing you have to remember: Head loss exists for many reasons, the only one that counts here is friction.
The head loss in your building example is due to friction loss only. Plug in the numbers in the calculator and it will give you about 12' head.
Ernie
Ernie
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