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Imbarrie

PADI Dive Inst
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There is a simple thought experiment that can show where this is true.
Think about the flow of fluid through the line when it hits the 90. All inertia stops and pressure builds up until it pushes the fluid through the only possible direction it can go. Wherever pressure increases flow decreases.
With the 45 it will do the same but to a much lesser degree because the flow is just redirected and not stopped.
 
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if the line is pressurized i think you would have the same flow with y or t. if their is no resistance and water is just flowing, the y will give more even flow. it all depends if their is pressure in the line. again just my opinion from working with hydraulics .

You're right with hydraulics but hydraulic systems aren't usually designed with flow in mind. Natural gas lines are similiar in that it doesn't matter how many fittings are used and there certainly are no "wye's" to be found. When it comes to matters of flow, the less restriction that is present equals more flow.
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I've done all kinds of piping and when it comes to anything in pressurized and in liquid form that needs to get somewhere fast it is best to have as little resistance as possible. The difference between a 90 and a 45 is significant. A 45 is more than 50% less restrictive than a 90. There are times where we are encourged to use (2) 45's instead of (1) 90 to create a 90 because of the fact that it is that much less restrictive. It's something that I rarely have to do but when pushing the limits in certain applications, ever little bit helps and I've had to use that technique.
 

thirty5

A Little Annoyed!
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You're right with hydraulics but hydraulic systems aren't usually designed with flow in mind. Natural gas lines are similiar in that it doesn't matter how many fittings are used and there certainly are no "wye's" to be found. When it comes to matters of flow, the less restriction that is present equals more flow.
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I've done all kinds of piping and when it comes to anything in pressurized and in liquid form that needs to get somewhere fast it is best to have as little resistance as possible. The difference between a 90 and a 45 is significant. A 45 is more than 50% less restrictive than a 90. There are times where we are encourged to use (2) 45's instead of (1) 90 to create a 90 because of the fact that it is that much less restrictive. It's something that I rarely have to do but when pushing the limits in certain applications, ever little bit helps and I've had to use that technique.

If you really want to get it even better, use a wide 90, the actual connections in the 45 (the glue points) will also decrease flow. I bet a wide 90 since is it smooth inside will actually be better than 45's
 
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If you really want to get it even better, use a wide 90, the actual connections in the 45 (the glue points) will also decrease flow. I bet a wide 90 since is it smooth inside will actually be better than 45's

You're referring to long.radius or long sweep
90's and those are all I've ever used and I I was referring to.those 90's (I should have said so) and the industry still.suggests (2) 45's over a L.R. 90. The larger benefits to using a single L.R. 90 over (2) 45's is less.cost, less labor and the fewer joints you make equals.the less possibilities for leaks.
 
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http://www.munchkinboiler.net/uploads/MunchkinInstallationManual40106.pdf

Take a look at page 16, table 4.1 ......it's referring to PVC intake and exhaust for this specific boiler. Also look at D #3 which says something about an equivalent of 85'. so (5)3" elbows would equal a 25' equivalent of straight 3" PVC pipe

The fittings become less restrictive with size becasue they are more passive.

I know it isn't water but it's an idea of what a 90 degree elbow vs. a 45 degree elbow can do to flow
 

edd

Advanced Reefer
Location
nj
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hydraulics will not function with out proper flow. the t fitting that skene displayed,those fittings are designed for fluid or gas under pressure, where you can have basicly have even flow. i think the only time y fittings are used is for gravity flow as in drains,what they were designed for. i was under the assumption that our tank return should have little restriction just flow. but i never seen 3/4 or 1" tees. so you would have to use 45s like you said sonny.if someone is really that critacle about even flow then use ball valves to even it out or neck one side down a size, i think that should work to keep flow even.
 
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hydraulics will not function with out proper flow. the t fitting that skene displayed,those fittings are designed for fluid or gas under pressure, where you can have basicly have even flow. i think the only time y fittings are used is for gravity flow as in drains,what they were designed for. i was under the assumption that our tank return should have little restriction just flow. but i never seen 3/4 or 1" tees. so you would have to use 45s like you said sonny.if someone is really that critacle about even flow then use ball valves to even it out or neck one side down a size, i think that should work to keep flow even.

I agree but ball valves are restrictive and account for more loss as well because of their imperfect design for that type of application. Ball valves are only to be used to turn things on or off. A gate valve or globe valve is what should be used to adjust and properly regulate flow.

Joe,

I dunno if you want to get this technical about the design of what you're getting into but if you do, just lemme know. The parts list is going to get pretty pricey tho but then again, in the long run you may be able to save quite a bit on efficiency in terms of your electric bill on the right design.
 
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hydraulics will not function with out proper flow. the t fitting that skene displayed,those fittings are designed for fluid or gas under pressure, where you can have basicly have even flow. i think the only time y fittings are used is for gravity flow as in drains,what they were designed for. i was under the assumption that our tank return should have little restriction just flow. but i never seen 3/4 or 1" tees. so you would have to use 45s like you said sonny.if someone is really that critacle about even flow then use ball valves to even it out or neck one side down a size, i think that should work to keep flow even.

Don't get me wrong, I just meant that hydraulics aren't typically aiming for higher rate of speed to move hydraulic fluid thru anything. Yes, a "tee" will evenly allow equal amounts of fluid to both sides but because there are no curvitures to help speed up the flow, there is a resistence that is made. Fluid runs into "brick wall" and is forced to go in 2 different directions. Also, there is a pocket of resistence made once again at both inside corners of the "tee" interfering with anything moving at a high rate of flow.

Like you said tho, this is a bit to criticle for a fish tank.

Even with airduct designs, a "tee" type of design is used but when efficiency comes into play, it is best done with radius bends or curved veins (wind veins) inside of a fitting to aid the flow of air move along more smoothly making a typical "tee" design obsolete. There are people who make radius outside bends and squared off inside bends and those squared inside bends restrict flow much more than if they were to make the inside and outside bends with a radius design.
 

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