HF dust collector flow measurements - Page 11 - Router Forums
 65Likes
Reply
 
LinkBack Thread Tools Display Modes
post #101 of 118 (permalink) Old 02-25-2017, 05:49 PM
Registered User
 
Bob Adams's Avatar
 
Join Date: Jul 2014
Country: United States
First Name: Bob
Posts: 192
 
Default

Quote:
Originally Posted by furboo View Post
Thanks Herb, I definitely plan to do something like this. Instead of using plywood, I might try enlarging the existing metal face and see how that goes. I do wish that I had held off upgrading the impeller until I had done this.
I understand the reasoning for increasing the intake to 6" but my question/concern is that without doing the same thing to the exhaust, it might create turbulence within the impellor housing. If that happened I would think any benefit would be lost. Looking at my unit I don't see any "easy" way of increasing the exhaust port diameter. I have no idea if this a valid concern or just me over thinking this....
Bob Adams is offline  
Sponsored Links
Advertisement
 
post #102 of 118 (permalink) Old 02-25-2017, 06:58 PM
Registered User
 
Join Date: Feb 2015
Country: Australia
First Name: Peter
Posts: 34
 
Default

Furboo,
My set-up with the pitot tube is the same as (c) in figure 2. The only difference is the type of manometer used.
All my new air flow measurements are now measured using a Hotwire anemometer and when I did a quick check between my Pitot tube set-up and the anemometer, they were within 2% of each other.
Dwyer were very helpful in explaining the measurements, which were accurate and which were not, what each one measured etc. and providing me with spreadsheets for various pressure and air speed calcs.

https://www.dwyer-inst.com/Products/...troduction.cfm

BTW. The formulae that BobL provided, as far as I know, is formulated from the graphs on Bill Pentz's site but I may be wrong
Herb Stoops and furboo like this.
Lappa is offline  
post #103 of 118 (permalink) Old 02-25-2017, 07:03 PM
Forum Contributor
 
Herb Stoops's Avatar
 
Join Date: Nov 2014
Country: United States
First Name: Herb
Posts: 7,403
 
Default

Quote:
Originally Posted by coxhaus View Post
Fire, that will do it. I am just hoping my 2 HP will work. I don't want to have to run a 3 HP.
Lee the 2hp worked just fine for me, it should work good for your setup. you running on 240v ?
Herb

Last edited by Herb Stoops; 02-25-2017 at 07:07 PM.
Herb Stoops is online now  
Sponsored Links
Advertisement
 
post #104 of 118 (permalink) Old 02-25-2017, 08:27 PM Thread Starter
Registered User
 
furboo's Avatar
 
Join Date: Oct 2015
Country: United States
First Name: Rob
Posts: 544
 
Default

Peter, what hot wire are you using?

Rob
furboo is offline  
post #105 of 118 (permalink) Old 02-25-2017, 08:38 PM Thread Starter
Registered User
 
furboo's Avatar
 
Join Date: Oct 2015
Country: United States
First Name: Rob
Posts: 544
 
Default

Quote:
Originally Posted by Bob Adams View Post
I understand the reasoning for increasing the intake to 6" but my question/concern is that without doing the same thing to the exhaust, it might create turbulence within the impellor housing. If that happened I would think any benefit would be lost. Looking at my unit I don't see any "easy" way of increasing the exhaust port diameter. I have no idea if this a valid concern or just me over thinking this....
Bob, it's not ideal. The 5" exhaust will cause more back pressure than 6", but I'm not sure a 6" intake size will necessarily be worse or better than 5". Another deciding factor for me is this fitting:

https://www.lowes.com/pd/IMPERIAL-6-...ke-Off/3307820

which doesn't come in 5"
Herb Stoops likes this.

Rob
furboo is offline  
post #106 of 118 (permalink) Old 02-25-2017, 09:05 PM
Registered User
 
Bob Adams's Avatar
 
Join Date: Jul 2014
Country: United States
First Name: Bob
Posts: 192
 
Default

Quote:
Originally Posted by furboo View Post
Bob, it's not ideal. The 5" exhaust will cause more back pressure than 6", but I'm not sure a 6" intake size will necessarily be worse or better than 5". Another deciding factor for me is this fitting:

https://www.lowes.com/pd/IMPERIAL-6-...ke-Off/3307820

which doesn't come in 5"
Thanks for the link. If you do this please keep us updated, about the performance. Because I have no problem copying you
Bob Adams is offline  
post #107 of 118 (permalink) Old 02-26-2017, 12:13 AM
Registered User
 
Join Date: Feb 2015
Country: Australia
First Name: Peter
Posts: 34
 
Default

I decided to upgrade my dust extractor in steps to see what made a difference either good or bad. I also decided not to destroy any component during modification si I could return the unit back to standard.

Step 1 = upgrade the inlet from 5" to 6"

Made a new front from ply and added a 6" PVC pipe. routed a radius on the intake

HF dust collector flow measurements-img_0262.jpg

My main concern was that the impellor was 12" but the centre section was reduced in blade size for 5" to match the existing 5" intake. I wasn't sure whether the larger opening would reduce pumping efficiency

Attached this to the impellor housing and ran more tests.

(NB. " H2O stated are conversions from mm H2O)

Maximum static pressure - Before 6.89" H2O, now 7.28" H2O - thats good!!
Current draw with inlet open and filter pipe disconnected - Before 3.36A, now 3.98A - thats good!!
Current draw with inlet connected to main ducting but pipe to filter disconnected. Before 3.30A; now 3.5A - good
Current draw with ducting connected and filter pipe connected. Before 2.78A; now 2.67A - thats Bad!!
CFM before approx. 450 CFM; now 456 CFM - Note. I was now taking readings in a recommended vertical matrix then running through a std, deviation spreadsheet so resulting figures are more accurate. So in reality, no real change in CFM.

All the tests seemed to indicate that while the increase in inlet looked good the restricted outlet was hampering the system.

To test this, I ran CFM tests and Amps tests

1) outlet pipe disconnected from the filter - result was 3.5A and 750 CFM.
2) outlet housing removed to expose large rectangular outlet - result 3.71A and 900 CFM. Further testing seems to have this figure steadily at at approx. 860 CFM
2) All back together again as normal - result 2.79A and 456 CFM

A this was a 2nd hand unit and the pleated filter was probably 5 years old and looked crusty, I removed it and fitted a needle felt filter that had been conditioned previously.
Results 3.5A and 665 CFM - thats great!!! So one of the problems was blocked filter.

Hopefully I can raise this figure further by removing the restricted outlet by opening it up from 5" to 6"

I'm halfway there.

HF dust collector flow measurements-img_0521.jpg
Bob Adams and furboo like this.
Lappa is offline  
post #108 of 118 (permalink) Old 02-26-2017, 12:59 AM Thread Starter
Registered User
 
furboo's Avatar
 
Join Date: Oct 2015
Country: United States
First Name: Rob
Posts: 544
 
Default

Peter, very interesting and looks really nice. In your first image, is the 6" PVC centered on the impeller axis? On my impeller housing, the current 5" inlet is centered on the impeller axis, which I just noticed is off center a bit from the housing.

Also, how did you attach the PVC to the wood?

Rob
furboo is offline  
post #109 of 118 (permalink) Old 02-26-2017, 01:35 AM
Registered User
 
Join Date: Feb 2015
Country: Australia
First Name: Peter
Posts: 34
 
Default

I took the front cover off the impellor housing and traced it onto the ply. I had marked the top of the housing before removal just in case there were any discrepancies. The new front was marked as well.
I added a 18mm "collar" from the pipe to the front panel, then used liquid nails and screws.

HF dust collector flow measurements-img_0263.jpg
furboo likes this.

Last edited by Lappa; 02-26-2017 at 01:37 AM.
Lappa is offline  
post #110 of 118 (permalink) Old 03-21-2017, 05:40 AM
Registered User
 
Join Date: Feb 2015
Country: Australia
First Name: Peter
Posts: 34
 
Default

My latest step was to add a 6" inlet to the separator. I still have to assemble the system and flow test.

HF dust collector flow measurements-img_0604.jpg

Furboo- reading through the posts I saw a question I didn't answer. The hot wire anemometer is a Testo Smart Probe Thermal Anemometer.
furboo likes this.
Lappa is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Router Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Tips for Installing a Dust Collection System Router Forums Featured Topics 121 02-24-2017 12:20 PM
Small shop dust collection Barry747 Shop Safety 4 10-12-2015 12:04 PM
A Dust Problem rrrun The Finishing Touch 15 01-19-2015 11:44 PM
Index of Dust Collection Solutions and Comments allthunbs Shop Safety 28 03-14-2014 02:40 AM
My Dust Collection System MAFoElffen Tools and Woodworking 19 05-23-2013 04:39 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome