Page 2 of 2 FirstFirst 12
Results 16 to 30 of 30

Thread: Any differences between clamp together piping?

  1. #16
    Join Date
    Nov 2007
    Location
    Goleta / Santa Barbara
    Posts
    841
    Pat, thank you kindly. Very much appreciate the insight and explanation!
    Best, Patrick

  2. #17
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    57,937
    "Ideally", having a nice straight run in would be desirable, but then there is the real world we all live in. We do what we have to do to fit thing where we need to fit them. The small system I'm putting in my temporary shop "kinda" has a straight run it from the tools in the center of the space, but the very first component off the SDD is a 5x5x5 wye because that's where the J/P has to connect. So that tool doesn't benefit from straight in but things will likely balance out because, well...the J/P, which is the biggest chip producer, is almost literally directly connected to the cyclone.

    -----

    I received my Blastgate Company order today. Gave them money late in the day on Tuesday and had two big boxes delivered by the big brown truck just after lunch. Everything was packed very well with extra protection on all the rolled edges. I'm looking forward to putting it all together.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  3. #18
    Join Date
    May 2005
    Location
    Highland MI
    Posts
    4,214
    Blog Entries
    11
    Quote Originally Posted by Pat Rice View Post
    I was blown away with the performance of this system and find I have to open a second Blastgate not to starve the system.
    Curious, what symptoms did you see that the system was "starving"?
    NOW you tell me...

  4. #19
    Join Date
    Nov 2017
    Location
    East Coast of Florida
    Posts
    54
    Ole, I have the Oneida Smart Boost Gorilla Pro, it will ramp up or down the motor speed based on restriction of air flow. If I only have a 4” port open the motor really increases its rpm, opening a second gate allows the motor to operate at a lower rpm. This is my non technical explanation and I am sure others can provide a better explanation. In my mind if Smart Boost really ramps up the motor speed it’s because air flow is being restricted or “straved”. This is my second Oneida in twenty years, my first was a 1.5 hp with internal filter that was very inconvenient to get to. A couple of years ago when I was upgrading several things in my hobby shop, I decided to upgrade to the Oneida Gorilla Pro with Smart Boost. I debated over whether to get 3hp or 5hp, I went with 5hp and have been extremely pleased with the dust collection and think that extra 2hp makes a big difference based on what others have posted.
    Last edited by Pat Rice; 07-03-2021 at 10:53 AM.

  5. #20
    A dust collection system is the one tool in the woodworking shop where the buyer has to design a significant part of the system. The duct system is expensive and critical to performance. Few people have the skills or time to actually do that. (Some people actually do it seems and dust collection becomes their hobby or job rather than woodworking. The other problem is that the designer/engineer of the other part of the system, the cyclone, fan, and filter, has no knowledge or control of the rest of the system that the user designs. It is surprising that there is no cottage industry of duct systems designer and installers to fill the gap.

    Three dimension turbulent flow modeling is one of the grand problems of engineering. The question above whether there is enough straight pipe leading into a cyclone is in that category of problem. There are a quite few PhD dissertations topics still available in figuring it out. Some things you can judge without going down the path of actually figuring it out. First, the fan and cyclone are optimized for fully developed turbulent flow. In fully developed turbulent flow in long straight pipes, the average streamlines are parallel to the pipe walls and the flow velocity profile is nearly flat across the pipe. Fan performance is greatly influenced by the velocity profile. Fortunately, the fan is not exposed directly to the inlet. The flow has to pass through the cyclone first. The cyclone is more forgiving of nonequilibrium inlet flow. The air has to make several circuits around the barrel and cone of the cyclone over which time the velocity profile assumes the profile for the cyclone before entering the fan. Hence, the textbook advice of straight pipe 10 diameters long can be relaxed a bit. It you browse through galleries at major dust collector manufacturers, you will see installations with an 90 degree elbow connected to the cyclone inlet. It does have an effect but not too much. The system I am currently running is a portable dust collector with 6” flexible hose falling at 90 degrees straight to the floor. It works. I have measured flow and pressure. As close as I can get to an accurate flow measurement, I get the rated flow for the pressure.

    One last comment for those with Oneida Smart or Oneida Supercell collectors, I am envious. As we said the dust collector has no knowledge of the connected system, both of these designs are trying to compensate for that lack of knowledge but by different means. Typically, an air handling system is designed for a specific flow and pressure which is called its system operating point. The fan is optimized for that one specific condition. For dust collection, there is no one single point. Different ductwork systems have different resistances. A specific system’s resistance changes as different blast gates are opened or closed. The thing Oneida has done is to try to make the airflow less dependent on the ductwork resistance than the typical high flow low pressure systems typically are. Their goal is to deliver the rated flow no matter what crazy thing the user does. The Smart collector monitors flow and uses a VFD (variable frequency drive) to speed up the fan if the flow drops. It only works over a small speed range (3450 to 4500 rpm) but it compensates for some common changes in system connected devices resistance. The Supercell works by using 3 vacuum cleaners in parallel. The vacuum system is a high pressure low flow device. Its fan curve is much steeper so a large change in pressure makes a much smaller change in flow than a high flow low pressure fan. It also works but makes more noise and uses more electricity. Sometimes that is the way to go.

  6. #21
    Join Date
    Nov 2007
    Location
    Goleta / Santa Barbara
    Posts
    841
    Thomas, your middle paragraph make so much sense. Heretofore i had not even considered the impact of the cyclone on the airflow once it gets past the inlet, but as soon as you pointed it out, i did the proverbial smack of my forehead . . . . Which is starting to hurt from getting hit so often recently . . . .

    Thank you very much, Patrick

  7. #22
    Join Date
    Sep 2013
    Location
    El Dorado Hills, CA, USA
    Posts
    205
    Another option, split the difference between a 90 and straight out. Oneida's design folks "approved" this.

    IMG_2332.jpg

  8. #23
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    57,937
    I can confirm that the Grizzly clamp works perfectly well on the Blastgate Company pipe.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  9. #24
    Join Date
    May 2005
    Location
    Highland MI
    Posts
    4,214
    Blog Entries
    11
    My concern in opening a second blast gate to avoid "starving the system" is that by doing so you are reducing the vacuum (opposite of pressure if you will) across the whole system and in doing so, you are reducing the airflow at the tool in use. And dust collection is all about airflow. Now if you throw enough horsepower at it, especially with a Smart Boost system you are likely still providing adequate vacuum and therefore airflow, so you are going to be ok, even though you could do better by not wasting airflow at an unused blast gate. Frankly, starving the airflow at the tool due to inadequate airflow there is a larger issue. That can be a more difficult nut to crack depending on machine dust hood design. Go large or go home?
    NOW you tell me...

  10. #25
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    57,937
    Ole, consider that the "vacuum" in a dust collection system is very low....static pressure is very low in most cases. Performance is always. about moving volume of air but at low negative pressure. So some systems really do need more than one smaller port open to operate at peak efficiency. The "smart" systems like Oneida is selling are able to compensate better as they can automagically adjust impeller speed, etc., when they sense an actual need for higher static pressure, et al.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  11. #26
    When laying out duct work, or really any type of pipe you do want to avoid back to back fittings. The old “rule of thumb” for air is 4 or 5 pipe diameters between to get back to good laminar flow. Being a R of T, that will vary by application and with dust/chips it is a whole different level of turbulence. Hard to argue with Oneida. If you can’t make your desired lay-out Patrick do avoid 90’s. Use 45’s instead. When you lay them our to figure the length multiply your center to center dimension by 1.414 and subtract the center dimension on each 45 or wye.

  12. #27
    Join Date
    Mar 2016
    Location
    Exeter, CA
    Posts
    541
    I have a cobbled together system (but it works). Some HVAC pieces, about 50' of 5" thinwall pvc, etc. I've bought a few pieces here and there over the years from blastgate (blastgates and flex duct), great folks to work with! Prices are good too. Randy
    Randy Cox
    Lt Colonel, USAF (ret.)

  13. #28
    Yes. I just mixed some components this week.

    To custom make a length of pipe, a sleeve is used over the cut end of a pipe. Blastgate Co sleeves are not compatible with Nordfab pipe. I suspect that Nordfab sleeves wouldn’t work with Blastgate pipe, but that’s a guess. The pipe diameter of the Nordfab pipe is ever so slightly larger than the ID of Blastgate’s sleeve. The piping and fittings do connect just fine. My guess is that is the only component that you would have to ensure stayed within the manufacturer’s family. Quality of welds looks the same to me. I’m happy with the Blastgate components and, except for some custom fittings I’ve had Nordfab make, I don’t see paying their prices again

  14. #29
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    57,937
    Jim, that's a really good data point to know. There's no getting around using the sleeves for custom lengths (unless you want to weld things) so matching the sleeves with pipe from the same source solves the difference, when doing "mix and match" components in the overall system. Thanks for the heads up!
    --

    The most expensive tool is the one you buy "cheaply" and often...

  15. #30
    Join Date
    Apr 2010
    Location
    Nashville, TN
    Posts
    1,544
    Straight duct on the cyclone inlet is generally for cyclone performance. The fan is already in a bad spot sitting on top of the outlet pipe. The spinning air of the clean gas vortex going through the outlet pipe has to be straightened or the fan has to power through it. Any time you have a spinning airstream in the inlet of the fan, it reduces its efficiency (takes more HP to do the same work). Adding straighteners is an option but it is something else to fail. For the small home systems, probably better to just let the fan power through it and eat some inefficiency. On a large system, the forces and vibration on the straighteners will cause fatigue and failure unless they are built to withstand it which costs $$. Also, on large systems, its impractical to mount the fan in the vertical position. Fan bearings are not rated for it and the cyclone roof, supports, and stand have to carry all that weight.

    The amount of straight duct needed is ultimately up to the OEM for the cyclone, but generally elbows on the inlet don't make a lot of difference unless it is a horizontal elbow that is turning opposite rotation of the cyclone.

    However, if you have a system with multiple cyclones in parallel, it is important to have straight duct on the inlet so that the cyclones are loaded evenly in terms of airflow and dust loading.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •