Closed loop random flow question

[Waxxiemann]

Squirts are morotized while the SCWDs are mechanically powered. The OM's are WAY more expensive than the SCWD's. Your lookaing at about a $400 dollar difference in price.

The OM gives you way more options in terms of what kind of flow you want to have by getting different drums you can create different flow patterns. Bassically it's just an oscillating drum with holes in it that allows flow to some outputs while denying others.

Good luck to you.

[Waxxiemann]

You said that you want some constant flow and some variable flow; why don't you make your closed loop constant and go with 2 tunze streams? Or even 1 tunze on a controller will give you lots of randon flow.

[Waxxiemann]

My bad, I was looking @ the 339.00 4 way, not the sqiurt.

[jdieck]

Originally posted by MarineGirl411
You guys there? What is the difference? How much different flow restrictions are there?

Question 1 Are you there?
Yes I am

Question 3 (2 will come after 3)

Flow restrictions are basically two types:
a) Static: Static restrictions are created by the need to lift the fluid. in other words the higher a column of water is (even without moving) the more it will push back at the bottom. because the higher the column the higher the pressure at the bottom you need a pump with higher discharge pressure for a higher water column. This is why you need a pump with a higher discharge pressure to pump from a pump in the basement to the living room than if you were just pumping from a sump in the stand.

b) Dynamic restrictions:
Dynamic restrictions have to do with anything that oppose to the movement of the liquid.

Pipe or hose diameter: In other words you can pass more cars at once trough a 4 line highway than trough a 1 line country road.
The higher the pipe or hose diameter the higher the flow. For every time you double the diameter you can pass four times more flow.

Pipe wall roughness: You can pass more flow trough a smooth pipe or hose than trough a pipe that is rough inside. Continue with the road, you can drive faster in a road without potholes.

Speed of the water: The higher the speed the more resistance to the flow you will find as all other dynamic restrictions become increasingly difficult as the flow speed increases.

Turns and funnel effects: Every time there is a change in direction or a change in diameter there will be resistance. While driving you will need to slow down at every curve ore very time the number of lines is reduced on the road
So the number of elbows and their shape can create resistance, a 90 degree elbow will create more resistance than a 45 degree elbow. A sharp 90 degree elbow will create more resistance than a 90 degree loom in a hose which has a longer turn radius.
Funnel effects can be created on valves, nozzles (which is a diameter reduction made on purpose) or anything that oppose the free pass of flow by reducing the sectional area of the pipe. The ultimate reduction is a valve that you completely close

A globe valve creates more restriction than a ball valve. In the first one the water enters the valve from a side then to the bottom of the valve then turns up inside the valve trough the seal seat and then turn again to the opposite side to exit the valve so in a globe valve you have 2 sharp 90 degree turns and a reduction in diameter at the seal seat, lots of internal restriction, this is why they are not sued for our purposes.
In a ball valve the internal sphere is drilled to the full diameter of the pipe so when you fully open the valve the flow may not even know there is a valve there as it just passes thru straight forward.

No imagine a device that has a hole all the way thru it will have a less resistance than a device that has gears or artifacts in the middle of the pipe.

Now to response of question 2:

For switching direction of flow from one pipe to the other there are many ways to skin a cat. In this case we have three different designs.
The SCWD in my opinion is the worst ofender, you enter the device from the bottom, inside the device there is a little plastic turbine right in the center of the flow connected to gears that turns one plastic gate around, as the water passes trough the turbine (a mini fan) it turns the gears which turn the gate around alternatively closing the flow of both exits of the device at the top.
Here you have the resistance to pass trough the turbine and gears in the middle of the flow, then you have the restriction to move the flow 90 degrees to one side or the other, the energy of the flow lost in turning the turbine and the funnel effect of the inlet and outlet insert connections which will have a smaller diameter than the hose you connect it to.
In my experience a SCWD can reduce the flow by as much as 40 to 50%. very inefficient. In addition because of debris, bacterial buildup or such the gears and turbine (Flimsy plastic) get stuck very easily. Even when new I purchased three and one did not even work that is 30% chance it will not work out of the box.
To make things even worst this guys made it sealed so you can not open it for cleaning or repairs. A wasteful trow away not worth the money.

The second design is used by the sea swirl and the WavySea: this devices in reality does not switch the flow from one inlet to two or more different outlets, what it does is to turn the pipe around. In other words it has a small electrical motor connected to a small section of pipe that oscillates sideways much like an air fan does.
The device is installed on top of the aquarium with the outlet inside the aquarium. Water enters horizontally on top of the device turns down and then turns horizontal again to exit trough the bottom outlet which is the one oscillating.
In this case you have two 90 degree angles but you have no restriction of gears or anything inside the pipe. and because the motor and links that move the outlet are outside of the water there is little chance it will have troubles due to debris inside.
The limitation is that still offer some restriction (as much as two 90 deg elbows and a little more due to the output pipe being reduced in diameter but the real drawback is that it can only be mounted on top so the wave making is limited to the top 1/3 of the aquarium.

Then the third design used by the Ocean motions Squirt:
Imagine a ball valve with one inlet and two outlets that has a motor instead of a handle. By turning the ball the flow is directed from the inlet to one outlet and then to the other.
Instead of a ball use one cylinder and instead of one inlet and two outlets you can use two, three four up to eight outlets.
This is IMO one of the less restrictive as the water changes direction only once and the internal diameter is almost the same as the pipe you are connecting it to but as it is installed in the pipeworks you may be forced to use additional fittings and elbows than you would otherwise so creating restrictions down the line.

Leak wise because the SCWD is the safest as it does not have any openings for the motor shafts so no need for dynamic seals.
Because of this the Ocean motions the seaswirl and the WavySea are limited in the maximum amount of pressure they can handle.
The SCWD is limited in the amount of flow as the higher the flow the faster the switching until it is so high it locks.

Hope this long stuff helps.