[BullHead]

Hi there!
Does anyone know what kind/size thread there is on a Dräger P-port? (Can it be something like M36x1?)

[narked at 90]

hi Bullhead the thread is M38 x 1mm
if you need some thing tapping with that thread i have made a tap just to use for p=ports
kind regards john routley

Quote: (Originally Posted by BullHead)

Hi there!
Does anyone know what kind/size thread there is on a Dräger P-port? (Can it be something like M36x1?)

[BullHead]

Quote: (Originally Posted by narked at 90)

hi Bullhead the thread is M38 x 1mm
if you need some thing tapping with that thread i have made a tap just to use for p=ports
kind regards john routley

Thanks!
This will be very usefull!
(I'm going to study CNC for 2 years, and will make some experimental stuff on my own)

[AD_ward9]

Quote: (Originally Posted by BullHead)

Thanks!
This will be very usefull!
(I'm going to study CNC for 2 years, and will make some experimental stuff on my own)

If making your own, there are a lot of improvements to be made to the P Port. In the Open Revolution Gallery you can find some pictures of our effort at improving it, including:
1. Increasing the bore from 22mm -24mm to 36mm to reduce breathing resistance. Even the 36mm port, has 3 times the resistance of an EAC scrubber cartridge.
2. Preventing it falling apart (which the Draeger originals do too easily), by increasing the thickness of the plastic and screwing the parts together from behind.
3. Double O rings on all ports
4. Deeper locking channel, for a more positive "click"
5. Putting a white line on the button such that it is visible only when properly engaged.
6. Changing the skirt material to allow it to be welded to the breathing bag, to prevent it pulling through due to bag stretch.

Another picture is below, showing how all the ports can be the same in a CCR: the one in the centre is a Draeger P original P Port for comparison. Pictures of the ports the other way up, showing the buttons, are in the galley.

Alex

[narked at 90]

hi alex i agree. i've been usuing the double oring for a long time now and increasing the boar size is a good move, personly i couldnt be bothered with a complete reinvent! but good on you for doing it,
the self distuctive nature of a standard p=port is a problem so far i havent had it happen when diving but it does happen on occations when im messing with gire.
personaly i would also add a second lock to the button as they some times get depressed when in enclosed cases and in counter lungs, this has been a problem on a number of dolphin convertions
i drilleed mine through the button and p-port case and inserted a pin, that stopped the button being pressed in unless the pin had been removed first.
then all you need to do is mass produce it and get the rest of the wold to buy it! i would
kind regards john routley

Quote: (Originally Posted by AD_ward9)

If making your own, there are a lot of improvements to be made to the P Port. In the Open Revolution Gallery you can find some pictures of our effort at improving it, including:
1. Increasing the bore from 22mm -24mm to 36mm to reduce breathing resistance. Even the 36mm port, has 3 times the resistance of an EAC scrubber cartridge.
2. Preventing it falling apart (which the Draeger originals do too easily), by increasing the thickness of the plastic and screwing the parts together from behind.
3. Double O rings on all ports
4. Deeper locking channel, for a more positive "click"
5. Putting a white line on the button such that it is visible only when properly engaged.
6. Changing the skirt material to allow it to be welded to the breathing bag, to prevent it pulling through due to bag stretch.

Another picture is below, showing how all the ports can be the same in a CCR. Pictures of the port the other way up, showing the buttons are in the galley.

Alex

[AD_ward9]

Quote: (Originally Posted by narked at 90)

personaly i would also add a second lock to the button as they some times get depressed when in enclosed cases and in counter lungs, this has been a problem on a number of dolphin convertions
i drilleed mine through the button and p-port case and inserted a pin, that stopped the button being pressed in unless the pin had been removed first.

You make a good point with the lock button (Green sent). We did experiment with a second button, but found it increased the chance of failure. We found the better solution was increasing the O ring pressure. This means that when greased with Crystalube, it comes in an out with about 1kg pull, but does mean you need a lot of pressure to get it out if it becomes dry. The pressure means that if the button is pushed, the connector does not fall out.

There are still improvements we are doing in the hard tooling. In case the weld to the breathing bag fails, we are increasing the skirt to 20mm wide so even when just screwed into a breathing bag, the port cannot be pulled out of the bag. It also reduces the stress a lot on the weld to the bag.

Alex

[narked at 90]

hi Alex, i can see the problem with a second button but a lock mechanism to the main button i think is a big bonus.
I've also found that having the second o-ring makes for a safer connection, with my mods to p-ports it is much harder to remove the port purely from friction from the extra o-ring and it would stop the port coming out even if not locked in place
i have also found a slightly wider lock groove makes for a much more positive and confirmed locking click
the other mod we did was to put an o-ring in the angled shoulder so if there was any neg pressure on the system it would increase the seal rather that trying to push past the barrel o-ring
i think the welded fitting in the bags is far Superior to the way people like APD do theres but because of None disclosure contracts i cant discus this with you openly but i believe you are part of these contracts already?!
kind regards john routley

Quote: (Originally Posted by AD_ward9)

You make a good point with the lock button (Green sent). We did experiment with a second button, but found it increased the chance of failure. We found the better solution was increasing the O ring pressure. This means that when greased with Crystalube, it comes in an out with about 1kg pull, but does mean you need a lot of pressure to get it out if it becomes dry. The pressure means that if the button is pushed, the connector does not fall out.

There are still improvements we are doing in the hard tooling. In case the weld to the breathing bag fails, we are increasing the skirt to 20mm wide so even when just screwed into a breathing bag, the port cannot be pulled out of the bag. It also reduces the stress a lot on the weld to the bag.

Alex

[AD_ward9]

Quote: (Originally Posted by narked at 90)

hi Alex, i can see the problem with a second button but a lock mechanism to the main button i think is a big bonus.

We should talk about this, as we did experiment with several options but could not find one which was a real benefit. With two buttons we found one could latch and not the other due to play in the spring/lever. Can you post a drawing?

Quote: (Originally Posted by narked at 90)

I've also found that having the second o-ring makes for a safer connection, with my mods to p-ports it is much harder to remove the port purely from friction from the extra o-ring and it would stop the port coming out even if not locked in place

We agree with this completely. All our units have the twin O rings, and we increased the pressure on the O ring as explained, so it is retained more forcefully.

Quote: (Originally Posted by narked at 90)

i have also found a slightly wider lock groove makes for a much more positive and confirmed locking click

Again, we found the same and is implemented on the ports shown in the photos I posted. The grove is about 50% wider and twice as deep as the Draeger original.

Quote: (Originally Posted by narked at 90)

the other mod we did was to put an o-ring in the angled shoulder so if there was any neg pressure on the system it would increase the seal rather that trying to push past the barrel o-ring

Interesting. We will think that one over. We went down the road of ensuring the latch is very positive, and clearly indicated to the user (with the white line). Once latched, it does not move in our out.

Quote: (Originally Posted by narked at 90)

i think the welded fitting in the bags is far Superior to the way people like APD do theres but because of None disclosure contracts i cant discus this with you openly but i believe you are part of these contracts already?!
kind regards john routley

We have so many NDAs, we would need to talk to find if we are dealing with the same one in this case. On the P Ports, the work is our own, so we are free to disclose.

When we are completely happy with the mould tooling, I am sure we can supply this for pricing similar to the Draeger ports.
Alex

[narked at 90]

Quote:

We should talk about this, as we did experiment with several options but could not find one which was a real benefit. With two buttons we found one could latch and not the other due to play in the spring/lever. Can you post a drawing?

not worth a drawing alex, just a small pin with lanyard that pushed through p-port housing around the button then through the button out the other side into the the housing again... just stopped the button being pressed and releasing the capture spring. all this means you can not engaged the pin untill the button is in the engauged possition.

Quote:

Interesting. We will think that one over. We went down the road of ensuring the latch is very positive, and clearly indicated to the user (with the white line). Once latched, it does not move in our out.

i went the same way but if you have movment in the catch system..as we both agree is better with a slightly wider grove then why not use that play to your advantage by adding a compreson o-ring, ok it may be over the top
but the option was there so why not use it?!
kind regards john

[AD_ward9]

Quote: (Originally Posted by narked at 90)

not worth a drawing alex, just a small pin with lanyard that pushed through p-port housing around the button then through the button out the other side into the the housing again... just stopped the button being pressed and releasing the capture spring. all this means you can not engaged the pin untill the button is in the engauged possition.

Good evening John,

Sorry, I may be dumber than usual today: any chance of posting a photo so I can understand exactly the double button arrangement you have?

On the shoulder O ring, what is the difference of an O ring on the shoulder and one in the barrel? The piston type O ring in the barrel is totally controlled, whereas the shoulder O ring is a face seal so depends on engagement pressure and the loop to ambient differential pressure. Again, it is getting late, and I had a 3am flight back home today (my excuse for missing something). Could you expand a bit more on the advantage.

Kind regards,

Alex