Does a wok rock or not

**Lappa** · 26th August 2017, 06:41 PM

As promised, I spent the day further modifying my genetic 2hp DC by fitting a wok. The size mentioned in most web posts is 14" but I could only buy a 16.5" one (425mm) so it's almost as wide as the inside of the separator.

The main reason for experimenting with the wok, is the huge amount of dust that sits on top of the separator when you remove the filter for inspection. As soon as you fire up the dusty, it's lifted back up and into the filter. The wok is supposed to keep the heavier dust below, in the bag.

I disconnected the filter assembly from the motor and moved it out into the year, attached with 3m of Flexi, so I could have easy access. This length of hose probably affected my readings so the final ones were done back in its shed as per normal.

IMG_0850.jpg

I look two measurements - back pressure just before the filter inlet and flow measurements in the overhead pipe in my shed ceiling which is were I have always taken flow measurements as it's a long, straight run. 6 flow measurements were taken across the pipe then fed through a std. dev. calculation as discussed with BobL earlier.

I took three sets if measurements - filter and bag attached, filter off, filter and bag off so just the separator.
These were done - before any mods, wok fitted in low position, wok fitted in high position level with the central hole in the separator then DC filter assembly back in the DC shed.

Wok fitted in raised position.
From Above
IMG_0851.jpg

From Below

IMG_0852.JPG
As you can see, there is only a small gap between the wok and the separator sides. In later tests I cut the wok down from 16.5" to 14.5".

Wok fitted in lower position

From above
IMG_0854.jpg

From below

IMG_0855.JPG

The wok was fitted 50 mm below the separator plate and the outer rim was actually below the separator body and in the bag.

All the results below are with the filter and collection bag attached.
The results of the tests are as follows.

a) tests taken on the 14th August after pleated filter was cleaned but conditioned
Back pressure 75mm H2O
Flow 548.8 CFM

b) test taken before modification today with 3m hose attached with filter and bag attached
NB. The paddles in the filter had not been turned.
Back pressure 75mm H2O
Flow 527.65 CFM

c) wok fitted in lower position
Back pressure 102 mm H2O
Flow 431.8 CFM

d) wok fitted in raised position
Back pressure 100 mm H2O
Flow 471.45 CFM

e) wok cut back to 14.5" (375mm)
Back pressure 93 mm H2O
Flow 474.65 CFM

e) dust collector with wok fitted to motor back in its shed
Back pressure 90mm H2O
Flow 507.8 CFM

As you can see, the wok is detrimental to the system with a rise of 15mm H2O in back pressure and a drop in flow of approx. 20 CFM

The drop is just under 4% which I can probably live with if it keeps the filter cleaner therefore a slower drop off in CFM and a longer time between cleaning.
only time will tell so I will carry out visual inspections to see if the dust IS being kept below the separator and back pressure and flow tests to check filter condition.

**Lappa** · 8th September 2017, 02:04 PM

It's been two weeks since the wok install so I decided to see how well it was keeping the dust/chips below the wok. I also decided to check the cyclone bucket on my 50mm system that I use for the saw table hood and router fence.

IMG_0863.jpg

I decided to suck that up as well before checking the wok.

This is the wok and the top of the separator which is normally deep in dust and some small chips
NB. I did not turn the paddles on the filter before removing it so there is probably fine dust up in the filter.

IMG_0864.jpg

Flow is still consistent with what it was in the last post as is the back pressure.
My only concern is that all the mods. to the system by increasing it to 150mm throughout has increased the flow to a level that the filter assembly can't handle ie. I need to increase the filter surface area, which is my next mod.
The lower bag is like a balloon ready to burst.

IMG_0865.jpg

I believe the wok, from this first check, is working by keeping the larger dust particles and chips in the bag and not up in the filter area where they used to be, then drop down onto the separator when you turned the DC off.

**woodPixel** · 9th September 2017, 10:44 PM

Might be a bit tedious, but if you had a mechanism to raise/lower the wok, one could fine tune to the lowest loss?

Im about to add a donut to mine (perhaps of wood) and a wok too. Luckily Ive a crappy mechanism for holding the obsolete upper bag in place so I could use that to hold everything in place. (something like this: Jet/HF Dust Collector Thien mods - Woodworking Talk - Woodworkers Forum)

I wonder what the optimum shape of the wok even is. I looked at Thien collector and its almost flat!!

**Lappa** · 10th September 2017, 09:58 AM

We think alike grasshopper

I tried my wok in two positions and the flow meter suggested the upper position was the best. I had thought about an adjustable unit but it's mounted on two bolts for security - it takes a buffeting!
I wonder about the position of the Thien plate in that link - normally it goes below the dust/air entry point unless they are showing the separator upside down

I already have one on a vacuum cleaner and it works a treat - that's the reason I'm building a big one for the second filter.

If you like, I could post my anemometer down to you so you could take some readings to make sure any mods are not detrimental.

**woodPixel** · 10th September 2017, 10:13 AM

I have to admit I'm having a lot of trouble understanding a lot of the tech talk. Something is not clicking together in my brain. I think I need to go back a re-read everything... Amps, watts, flow, static pressure (???? What does this mean).

With the anemometer, I'll need to work out where to put it. Do you have pictures of yours?

In the meantime I'm happy to read your adventures!

**Lappa** · 10th September 2017, 02:09 PM

Connected the new outlet to the separator 125mm outlet ans side of shed, still haven't gone into the Thien separator but the figures and visuals look good.

Bag on only - back pressure 58 mm H2O. Now 38 mm
- Flow 549.4 CFM. Now 612.47 CFM

Bag and Filter - back pressure 93 mm H2O. Now 65 mm
- Flow 467 CFM. Now 564.00 CFM

Sucked up a bucket of sawdust and chips - now sure it's only a visual thing but only minor amount out new outlet, most into the bag. Will measure how much when I build the separator but happy so far.

***** Moderators, please remove. In wrong thread

**Lappa** · 10th September 2017, 04:13 PM

Drum connected

IMG_0879.jpg IMG_0878.jpg

***** Moderators, please remove. In wrong thread

Thread: Does a wok rock or not

Thread Tools

Search Thread

Does a wok rock or not

2 weeks on

Similar Threads

Rock Wallabies

Bit of Oz rock

You're never too old to Rock'n'Roll

the rock

A big Rock.

Posting Permissions