Pan-caking , another look. Could it possibly work

Pan-caking , another look. Could it possibly work ?

PROBLEM  …..Pan-caking.

PROBABLE CAUSE….

 I think it is pretty generally accepted, certainly within this Forum, that the main cause of the trouble is that of the two sheets of the appliance get stuck together by waste matter.
Just how this starts is a matter of some conjecture, but it does happen and the task is how to overcome this problem, several ideas, lubricants etc. have been tried all with varying degrees of success.
I put forward this idea for a general kick around, could it work ?

  CONSTRUCTION

The bag to be constructed with three sheets. The rear sheet as normal.
The center sheet to be free hanging on a draw-string that comes in on one side of front sheet and exits on the opposite side .
The draw-string would have to enter and exit through dense rubber discs that would allow a seal of string ,and seal up when draw string is removed.
The draw-string itself would have to be something very strong such as nylon ,catgut or material used for medical sutures etc.

THEORY

The user becomes aware that there is a pan-caking situation developing, with no deposits in bottom of bag, and becoming obvious that the dreaded  “ Mushroom ”is forming between the stoma and the front sheet. ( Which is now a double sheet. ) The user now pulls out the draw string thus allowing the center sheet to fall with waste attached to the bottom of bag.

FOR………   Very little in bulk or weight.

AGAINST….It might work once, would further output of waste follow to bottom of bag.


Simple line drawing attached to give some idea how it would function.


Len.

                                                 Explanatory notes of diagram
                                                  ------------------------------------
.
Green Central Sheet,  ( Colour only to show general idea )

No 1.….Dense rubber discs, to allow seal around Draw-String.

No 2.…Draw-String, can be pulled either way, ease of use for left handed users. 

Hello Bii,
 Thank you for your input, it is great to get some interaction with you guys up there ! ! !

I have for some time now, thought if we had some physical connection with the happenings within our bags, and in some way could alter, or adjust things, it would overcome so many problems ....hence the draw- string idea.
( 1 )    Now I take your point, I agree with you it would need a little trial and error to get right, I reckoned on the use of rubber discs for the entrance/exit holes , thinking in terms of at least 4mm thick, this of course would depend on the material chosen for " string " but if threaded through rubber with a good tight fit I would think it a fair chance of success. After all we are not talking high pressure here.
( 2 )     It has been my own experience that it is true quite often, there does seem to be a vacuum within the bag at the same time as a major pancaking , however personally, I have found this not always the case, especially in the early stages, I rather suspect the vacuum is the result not the cause of the problem. ( Very interesting  " chicken and egg " situation here. )

With reference to your question of different appliances, believe me if they are out there I've tried them. I do not think there is anything one can do once the pancaking is established, the build up of pressure inside of the stoma is going to force a passage somewhere for the waste to exit, the base plate is therefore the only place to go....and it usually does.

I am busy at the moment, carrying out some modifications to a bag, intending to try test the theory of the draw string, will keep you posted if I ever find the courage to test fly it.

Thanks again....L EN   

Hi arthur,
          
       Sorry! don't think your theory stands up ref. static, if you are suggesting the front film is attracted to back film that way.
IF, the two films were separate sheets,and insulated from each other, this might be a possibility, although I have great doubts on this, however this is not the case, once the two sheets are welded, they become one sheet, any static in either sheet would then be quite unable to attract the other.

I have by the way, tried to generate static on a new sheet of the plastic used for constructing bags, I have to say personally I had no success, would be interesting if others have tried.

Keep thinking........Len.     

To all followers of this thread.......  Re. reply to XP-dkbva  22 July.

Today is the chosen day of the  " test flight ".... will keep you posted. .

Len.


Edited by L.Piper - 05 Sep 2010 at 6:57pm

Well here we go Bert...
May I first state that at no time during the recent  “test flight ”did I have to deploy the ejector seat or resort to a parachute. That being said I shall now report my findings….

The modified appliance (photo attached ) was fitted at or around 8am .
Normal duties were carried out throughout morning, including gardening, washing car  and shampooing the dining room carpet.
During this time there was no trace of odour, the normal filters worked well.
By 11-30 it was noticeable that there were no deposits in bottom of bag, a good sign that I had picked a good day to test the pancaking  scenario.
Fairly heavy lunch at 1 pm, it was now clear that the “ mushroom “ was beginning to  form. ( All those who are cursed with this problem will know what I mean. )
Continued duties until about 4 pm ,when it was clearly apparent I had a full scale pancaking developing. At this stage the normal filters were working perfectly well, there being no odour problems at all.
At 6 pm I pulled out draw string , everything going  fine and according to plan.
About an hour after removing draw string it was quite obvious that a major pancaking  was now developing  and it was also obvious that  my theory was beginning to go “ pear shaped “.
At 9 pm the appliance was changed, the pressure at rear of blockage was building , and waste had now forced between the flange and flesh , it would only have been a matter of time before a full blow out.
Upon close scrutiny of appliance after removal it was clear that although the draw string removed perfectly as planned , the center sheet had not dropped at all., waste matter had worked its way around whole assembly, and it was one solid mass. As per mushroom head. It was also noted that the remainder of the interior of the bag was completely airless, complete vacuum as far as one could determine.
In conclusion I would say
 Bii was quite correct in his conclusion that the center sheet would fail to drop, on removal of cord.
I did find that the odour seal of draw string through rubber seal, was not an issue.
As for myself…..it’s back to the drawing board

With regard to the question..." could it possibly work " on this occasion I can only and sadly say NO.

Len....