CT Extractors - Why no 'bag full' indication?

[martingchapman]

Hi all, this is my first post so hope I am not covering old ground, apologies if I am.
I am thinking about buying a CT dust extractor but am puzzled that there is no indicator to show when the bag is full.
Festool seem to think of everything with their tools so I wonder why there is no bag full indicator, or am I missing something?
Is it obvious the bag is full because the performance drops noticeably or is there a switch that automatically stops the extractor when the bag is full?

Any help/comments from existing CT users would be much appreciated.

BTW, great forum, well done to all involved in creating it and all the contributors who make it work.

Thanks in advance - Martin.

 

[Llap Goch]

Hi Martin and Creoso from a very wet and windy Wales!

You got it in one really. The suction power begins to drop off when full and when you remove the disposable bag you will notice that it is like a bag of cement that has set hard.

Cracking extractors. You will be amazed at their efficiency and portability.

Pat

 

[Jesse Cloud]

Hi Martin,
There is a thread in the "Wish List" forum asking Festool to consider a bag full gauge.  You are not alone.

In my experience, the CT22 keeps chugging along right up to the "concrete bag" stage described so well above.  It is amazing how much the little guy can hold.

 

[martingchapman]

Pat,
Thanks for the quick response, glad to hear the extractors work so well.

Jesse,
Thanks for the pointer to the wish list. Has there been any response from Festool to this list, do they read the forum and respond?
If there is any chance they may incorporate a dust full indicator then I will wait for that, but it would be nice to know if this is possible or I am wasting my time and I should just go ahead and purchase now.

Thanks again - Martin.

 

[Llap Goch]

Martin

There has been some discussion over here in the UK re bag full indicators but the general feedback was that the drop in suction power was a much more reliable indicator. Plus it might add to the cost of what is already perceived (by the great unwashed) to be an expensive extractor.

Festool claim that the disposable bags will fill to over 90% capacity and my experience thus far is that it exceeds that and fills almost up to the inlet hole. That is when you notice its time to change the bag. Some folk open the bottom seam, empty and tape it up to use the bag again but I have not found a tape sufficiently strong (even 100mph tape) to ensure the dust stays in the bag.

As for waiting. That is personal choice but in the meantime your lungs will fill with dust and your floor will be covered in shavings. ;D

 

[womackdesign]

Pat, who is your Festool dealer in the UK. Can you give me their email address. The guy I used to buy from in Norwich is not around and I don't  want to talk to Axminster. Thanks.Chad

 

[martingchapman]

Pat,
Thanks very much for the advice, and yes you are right, waitiing is not the best option.

Chad,
If you are looking for a Festool supplier can I suggest Andrew at Festool Fanatics;http://www.festool-fanatics.co.uk
He is very knowledgable re all things Festool and prepared to negotiate.

Martin.

 

[womackdesign]

Matin, Thanks I give him a bell.

 

[Llap Goch]

Hi Chad

Heard lots of good things about those chaps but I must admit that I have bought most of my stuff in Germany as we go over a few times each year in our motorhome. I found UK dealers came out in a sudden rash when the word discount was mentioned plus I got sick of being served by disinterested spotty youths on
day-release from the Home for the Bewildered. All of which was in marked contrast to the German dealers who had the tools on display and knew and cared about the product.

In the last year or so the UK dealers have improved and I have had excellent service from RM Hire in Wolverhampton (Roy Tulley used to be a Festool area representative so always excellent advice plus it is the family firm) and Toolsave in Birmingham where Simon really knows his stuff. Both can and will do a good deal. Their telephone numbers on the UK Festool site.

Pat

 

[Dixon Peer]

Well, hello Chaps!  ;D  Apparently, a lot of our "members" are from G.B.

I too have wondered why such well engineered dust collection tools don't have some indicator of being full to capacity.  Perhaps it is best to just wait until the thing moans with exhaustion from being overloaded; at least then you're getting maximum value from your very expensive bags.

 

[Mirko]

Hi Guys,
I believe a bag full indicator would be a tricky thing to get right in engineering, by reason, when the vac is "on" the bag blows up like a balloon, and completely engulfs the inside of the vac. I assume, while running, the bag would feel hard because it is full of air, simulating a full bag.
IMO the only simple way would be to use a scale that is set off by weight.
Just out of curiosity lift you vac while its empty, knowing that, we should know how heavy a full vac feels.

Mirko

 

[semenza]

Hi Guys,
I believe a bag full indicator would be a tricky thing to get right in engineering, by reason, when the vac is "on" the bag blows up like a balloon, and completely engulfs the inside of the vac. I assume, while running, the bag would feel hard because it is full of air, simulating a full bag.
IMO the only simple way would be to use a scale that is set off by weight.
Just out of curiosity lift you vac while its empty, knowing that, we should know how heavy a full vac feels.

Mirko

      I had posted this on the wish list thinking that it shouldn't be that hard to do, but it is perhaps more difficult than it seems at first.  The weight will depend on the type of dust, shavings etc. 

Seth

 

[Wim]

I have a domestic vacuum-cleaner from Miele (yes, also German, but not green) with an under-pressure indicator. It is connected to the space, where the bag is placed. When the bag is filling, the pressure between the bag and the fan is getting lower and the indicator shows more red on de dial. That should work also for any other type of vacuum-cleaner/dust-collector. IMHO a small and simple addition.

 

[martingchapman]

Hi chaps, thanks for the interest and replies on this one.

Semenza, that system obviously works well for Miele, maybe it is patented?

Another way to do it may be to have a (lightly) spring loaded plunger pressing down on the top of the bag with a detector on the plunger to operate an electronic indicator (maybe a light) when it was in the fully up position.

When the extractor was switch on and sucking this plunger would be forced up by the bag being blown up hard so, through an electronic switch the extractor would ignore this, however if the plunger stayed up when the power to the motor was switched off (and it was not sucking) then it would indicate the bag was full and the indicator light would be lit.

Just a thought - Martin.

 

[Michael Kellough]

On the front of the CT 22/33 there are two raised circular areas between the hose port and the power switch knob. The lower of the two raised areas houses the speed control knob. I seem to remember being told that the upper area holds a suction indicator or control on the German versions of the vacs.

 

[SteveD]

I have the same 'wish list' item. However as I looked at it there were two issues or, depending how you count them, three.
Firstly detecting the bag is full. Difficult. Detecting a loss of suction, i.e. a pressure difference, is relatively easy. However this only measures it whilst the system is running. Useful, but not a 100% solution. You would also need to factor in 'the wet' look.

Detecting by weight is possible, but l fill a bag with shavings from the 850 planer in no time and thisdon't weigh all that much compared to the bag when full of dust from the saw.

And then what do you do when the bag is full? When you are running the HL850 or TS saw at the end of the hose and wearing earing protection neither a buzzer not a a dial indicator will be of much use. The only solution I came up with was a serious flashing light. Not so serious as to make you jump but enough to make you aware.

A friend of mine made a suggestion that actually made some sense (business opportunity for someone). This is to have a universal multi pattern vibrator alarm (say with 5 channels or vibrator patterns) on your belt or wrist, and have multiple transmitters. The phone would have one vibrator pattern channel (and type of sensor), the doorbell another. Then you could add sensors for various other items such as the bag full on the vacuum (or the can full on a big cyclone). Going from tool to tool in the workshop would need no change of receiver and you don't need to take off your ear muffs. As with a cell phone (where you can set different ring tones and vibrator patterns) one would quickly learn the 'feel' and decided how to respond. You could even have two transmitters on the same channel. The vac and cyclone full sensors could share a channel for instance. Back door and front door. There is also no reason that several people cannot each have their own receivers and share the same vibrator patterns. (By the way this would help the hearing impaired)
  As a Festool solution, not likely to happen. However if there was a 'standard' out there then creating and adding a sensor that could interface to the transmitter it would be a possibility - or an aftermarket opportunity.

And no, this would not help unless the vac is running. It should, however, be quick enough to detect the bag is full before you start cutting.

SteveD

 

[Dave Ronyak]

IF a "bag full" indicator function is being contemplated, why configure it to also shut off the vacuum when the bag is full, or the suction falls below some predetermined threshold [and any tool plugged into the vacuum machine]?  In such cases, the operator would have to change the bag, remove the blockage, etc. before continuing, but that would save further clogging the hose and a bigger mess to clean up.

Dave R.

 

[greg mann]

I believe the Euro systems have the vacuum loss detection as a requirement. Whether it shuts the whole system down or has an indicator light (siren?) I don't know. It seems this was deleted for the US market, possibly to reduce the price point or, maybe, because UL didn't like it. NIH, you know.

Greg

 

[Wim]

According to the German manual the CTM series of DCs have a vacuum monitor. Below a airspeed in the hose of 20 m/s, a acoustical alarm will sound. From the German Festool site you may download the manual as a zip file. Look for "saugen" (= sucking). Then for "Betriebsanleitung". The manual is a multi-language version.

 

[martingchapman]

Chaps,
Thanks very much for the continued interest in this.
I have looked at the UK user manuals for the CTL and CTM series of extractors.

The CTL series have no form of vacuum loss detection but they do have a bag full indicator? However this is only mentioned in regards to Vacuuming liquids, the manual says, quote;
"The filter bag has to be removed before evacuating liquids. We recommend use of a special wet filter. When the maximum filling level is reached, a bag-full indicator (2.12) automatically interrupts extraction."
This suggests there is a bag-full indicator but it is only effective when vacuuming liquids, which is odd since you have to remove the bag to vacuum liquids?
Nowhere else in the manual does it mention the bag-full indicator.

In the CTM manual it does talk about Volume flow monitoring, quote;
"4.3 Volume flow monitoring
If the air speed in the suction hose drops below 20m/s an acoustic warning signal sounds for safety reasons.
Possible causes and adjustments
• Cause
? Adjustment
• Suction force regulator (1.4) set to a too low value
? Adjust suction force regulator to a higher value
• Rotary knob (1.2) not adjusted to the connected hose diameter
? Adjust to correct hose diameter
• Suction hose blocked or twisted
? Remove blockage or twist
• Filter bag full
? Change filter bag
• Filter element dirty
? Change filter element
? Only when operating without a filter bag: clean filter element
• Electronic monitoring system malfunctioning
? Call Festool customer service for adjustment
• Wet suction
? Functional safety not impaired; no action necessary"

From the above it seems the CTL series does have a bag-full indicator but it is not clear if it operates when the bag is full (as you would expect) or only when the container is full of liquid, when it will cut the extraction.
The CTM series will give an (acoustic) indication when the bag is full (as well as for other conditions).

Any UK owners of CTL or CTM extractors able to confirm what the user manuals say??

Martin.