Why are manufacturers still using 90 degree angles for vacuum input on their machines? 90 degree bends, vac ports all restrict airflow, cause air turbulence, and frankly i feel is a cheap way out when it comes to manufacturing. why wouldnt you put a soft 90 degree thats just bent tube to keep the airflow uniform?
Food For Thought?? 90 Degree angles ??
- Thread starter Scott S.
- Start date
Lee Stockwell
FOJL
Preaching to the choir...
Mikey P
Administrator
Same reason some offer 3 series blowers I suppose..
"it's a step up from a portable..."
"it's a step up from a portable..."
Mikey P
Administrator
roops....
sorry!
buy hey, it's better than a portable!
sorry!
buy hey, it's better than a portable!
Lee Stockwell
FOJL
I can visualize pallet loads of 2" galvanized 90 deg. elbows being used by the Texas mfgs...
ruff
Member
hydracat
Member
Replaced mine with a straight about a year ago. had It lying around for a year before that. Worth the trouble of the 1 minute it took to swap.
Desk Jockey
Member
Harbor Freight & Ace Hardware darlings.
Larry Cobb
Member
A recent #5MR Blower on DC538 ; dual 45 elbows . . .
. . . Massive Thick Dual 2.5" Intakes
rwcarpet
Supportive Member
Smooth flow elbows make a big difference. My Thermalwave uses 2 90* smooth flow els and a 4" smooth flow into the waste tank.
rwcarpet
Supportive Member
My smooth flow into the prefilter box. Drastic increase over the 2" inlets!
hogjowl
Idiot™
Out cleans a #6 blower?
Nate The Great
Member
8flow, #3 blower, 1 hour dry times.................. He knows a few things we all can learn from..............
hogjowl
Idiot™
8 flow
dgardner
Moderator
The difference between a 90° mitered ell and a smooth sweep is well-documented in the air duct world. They figure losses as equivalent length (EL) - in other words if a fitting has an EL of 50 it means the fitting causes as much loss as adding 50 feet of straight duct.
Although round air ducts are not usually smaller than 4" the results would be very similar for any round hose/fitting.
A smooth 90° swept ell with a radius at least 1.5 times the diameter has an approximate EL of 10 (for a 2.5" ell this would be a bend radius of around 4").
A 90° mitered fitting made by cutting straight pipe at a 45 and joining them together has an approximate EL of 75. It's like adding 75 feet of hose to your existing hose run.
In other words, switching from a mitered elbow to a smooth elbow would give you the same performance gain as chopping 65 feet off your hose run (!). Not earth shattering, but not trivial either.
Although round air ducts are not usually smaller than 4" the results would be very similar for any round hose/fitting.
A smooth 90° swept ell with a radius at least 1.5 times the diameter has an approximate EL of 10 (for a 2.5" ell this would be a bend radius of around 4").
A 90° mitered fitting made by cutting straight pipe at a 45 and joining them together has an approximate EL of 75. It's like adding 75 feet of hose to your existing hose run.
In other words, switching from a mitered elbow to a smooth elbow would give you the same performance gain as chopping 65 feet off your hose run (!). Not earth shattering, but not trivial either.
bob vawter
Grassy Knoller
the word yor searching for is called a mandrel bend.....and guess what....my new Genie has 'em
dgardner
Moderator
True Bawb - although the mandrel bender is just one of the ways a crinkle-free elbow can be made (casting comes to mind as another).
dgardner
Moderator
And good on ya for maximizing the potential on an already great machine!
dgardner
Moderator
Before the engineers (and Marty) come out of the woodwork to correct me, I should point out that the ribbed vacuum hose we use most certainly has a different friction rate than the smooth duct used in the table, so the precise improvement would be somewhat less than I quoted....
