1. The Forum Rules have undergone some minor changes and updates.  Please take the time to read them; it will only take a couple of minutes of your time. By doing so, you lessen the chance of incurring the wrath of the moderation team or making yourself look foolish to other members.

    90% of users posting adverts in the Sales forums need to be reminded to read the rules as their posts are wrong.  This is unnecessarily time-consuming and will no longer happen - if your advert doesn't follow the Sales Rules it will be deleted and you'll have to start all over again.

    To close this box once you've read it (and the Rules), click on the X in the top right-hand corner.

    Thank you.

    AGF Staff



    Dismiss Notice
  2. A reminder of one of the Forum Rules:

    'Behaviour

    Do not make inappropriate or offensive posts - including threats, harassment, swearing, prejudice, defamation, deliberate insults or name-calling, other negative remarks about this forum, its moderators and administrators or your fellow members. Even if this is just your own personal opinion, RESPECT YOUR FELLOW MEMBERS.'

    There have been changes made to our censoring software in an attempt to help with this growing problem.

    Click the X in the top-right-hand corner to dismiss this notice.
    Dismiss Notice
  3. Dear members,

    Our membership (like our country) consists of people from all walks of life; different in far more ways than can be listed here and each with a different view based on their experience of life - regardless of their colour, religion or cultural heritage. Every single person in the UK has been born of mixed race – we are a multi-coloured and multi-cultural country.

    As many of you are aware there are a handful of individuals amongst this membership that persist in making provocative, inflammatory, racist and otherwise offensive comments. This has been happening across the forum to a certain degree but is most especially prevalent in the Adult section.

    The moderation team has tried to stay on top of this, however unfortunately because of the ‘offensive’ nature of much of its content we don’t monitor the Adult section quite as much as perhaps we should. As a result much of this behaviour has gone unnoticed unless it has been reported to us. While the team always intended to take a "light touch" approach to the Adult section it would seem that some people aren’t quite adult enough to be left unmonitored after all.

    This behaviour is, and always has been against Forum Rules as well as the specific stipulations of the Adults forum and it will no longer be tolerated. We feel it's time to draw a line in the sand and as such from this point onward offenders will receive an immediate and permanent ban from the forum.

    In order for us to achieve our goal of restoring the forum to the friendly and tolerant place it once was, we ask that ALL members be mindful of the content they post and help us to stop unacceptable behaviour by using the 'Report' tool at the bottom of any offending post - the results of which can be seen only by Admin/Moderators.

    You should all receive a copy of this message by PM. 

    To close this message box, click on the 'X' in the top-right-hand corner.

    Dismiss Notice
  4. Hotmail block emails from us entering your inbox. Unless you can setup a safe sender you will not get activation emails from the forum. Please use an alternative provider or complain to Hotmail.
    Hotmail addresses include.

    @Hotmail.co.uk @Hotmail.com @outlook.com @Live.com
    Dismiss Notice
  5. Postings on Politics, Religion & Controversial Off-Topic Material

    The majority of users do not want to read about these subjects and people have left the forum as a result of it – this is after all an 'Airgun' Forum. It’s all very well to say they don’t have to read it if they don't want to, but as most of us use the ‘New Posts’ button there is no easy way to avoid it.

    All AGF staff members are in favour of people being able to discuss what they want, but we have to draw the line somewhere if it is upsetting other users. We don’t want to read about these topics either.

    IMPORTANT- The discussion of politics and religion is no longer allowed anywhere on the forum (including the Adult section).  The only exception is if it's airgun related - they must be put in the Airgun Related Politics section..

    We will not tolerate bullying or personal attacks, racism or any other offensive 'isms'. we will remove these topics from the forum, we will not give you an area where you can abuse each other. We will not hesitate to ban offenders.

    To clear this text box, click on the 'X' in the top right-hand corner.

    Dismiss Notice

PCP top up's & dive tank size?

Discussion in 'Anything Airgun Related' started by Honest Bob, Aug 2, 2014.

  1. Honest Bob

    Honest Bob Big Poster

    Messages:
    3,098
    Likes Received:
    8
    Location:
    Yorkshire.
    Let's say a 300 bar 3 ltr dive cylinder, gives X number of rifle top up's, would a 4 ltr cylinder give double the number of top up's, or is it not that simple. Thanks for your reply's. Bob.
     
  2. Kenbarcon

    Kenbarcon Donator

    Messages:
    3,104
    Likes Received:
    13
    Location:
    Hunmanby, Filey
  3. mark112

    mark112 Engaging Member

    Messages:
    335
    Likes Received:
    3
    Location:
    Coventry
    If I fill my 216cc S400 to 170 bar and refill it when pressure drops to 100 bar a 3L will give 24 fills and a 4L one 32 fills according to my own reckoning.
     
  4. cloverleaf

    cloverleaf Super Moderator Staff Member Mod/Admin

    Messages:
    21,838
    Likes Received:
    30,110
    Location:
    Oxfordshire
    Why should a cylinder of 1.33 times the capacity give twice as many fills? I don't understand where you're getting this relationship of "double" from..

    All else being equal (rifle fill and refill pressure, cylinder pressure, line lost volume) the number of fills will scale with the difference in capacity - the 4L cylinder is 1.33 times larger than the 3L item; so will give 1.33 times more fills.

    If you're considering the new MDE 4L stubby cylinders; they have a nice form factor and seem a bit more practical the an 3L offerings (they stand up on their own and don't roll about while you're trying to operate the valve). They cost a bit more but I think I'd go for one over a three :)
     
  5. Honest Bob

    Honest Bob Big Poster

    Messages:
    3,098
    Likes Received:
    8
    Location:
    Yorkshire.
    First of all, Thank you for the reply, but please read my question again, as I am was asking about top ups. ie, if I fill my gun to 200, then top up when it reaches 90, a 3 Ltr bottle would have 1 ltr of usable air, but a 4 Ltr would have 2 Ltrs of usable air, just wondered if it was that simple, it may sound like a stupid question, but I know nothing about PCP's or dive tanks. But once again thank's for your reply. Atb, Bob. PS. This link may help some people looking for cheaper bottles with refill kits. http://www.godive.net/
     
    Last edited: Aug 2, 2014
  6. terry1001

    terry1001 Major Poster

    Messages:
    9,153
    Likes Received:
    2,216
    Location:
    Ipswich
    The number of fills and/or top ups will depend on the volume of your bottle and the pressure of the air in it. The calculator linked to above (there's also one in Chairgun) will give you some answers. However you don't have to wait to top up until the rifle pressure drops right down and you don't have to stop when your cylinder pressure reaches your normal fill pressure. If you (for example) normally fill to 170 bar and top up when the pressure drops to 110 bar and get 60 shots (figures chosen because it gives 1 shot per bar used) then if your pressure drops (in the bottle) to 160 bar you can still top up your rifle and get 50 shots out of it. Basically even when the bottle pressure drops below your normal fill pressure there is still plenty of usable air in it if you don't mind topping up a bit more often - it will save you a bit of time and money.
    So, the calculator will give you some comparisons but how you use it can make quite a lot of difference.
     
  7. cloverleaf

    cloverleaf Super Moderator Staff Member Mod/Admin

    Messages:
    21,838
    Likes Received:
    30,110
    Location:
    Oxfordshire
    No problem - I sort-of see where your factor of two came from now :p

    I'm afraid it's not that simple as your thoughts fail to take into account the differences in pressure and volume between your rifle and they cylinder; as mentioned in my other post a simple volume scaling factor between the two will work to calculate the relative difference in the number of fills, though.

    As Terry says, try putting your values into the calculator to see what happens - failing that I do have a spreadsheet at home that seeks to work such things out (it can be done, just takes more time than I have to explain today) if you're still having issues on Monday PM me and I'll send you a copy :)
     
  8. Honest Bob

    Honest Bob Big Poster

    Messages:
    3,098
    Likes Received:
    8
    Location:
    Yorkshire.
    Thanks. I have just used the tool, and it appears that if I go from a 3 ltr bottle to a 4 ltr bottle, I would double the number of top ups. Once again I would like to say thank you to all who have taken the time to reply. Atb, Bob. PS. But sod the cost, think I will just get a 12 ltr 300 bar bottle, it should last me at least a year, before I would have to get it filled. Unless I take up paper punching, or HFT/FT.:rolleyes:. In fact, at the rate I shoot, it will still be half full when I'm pushing up the daisy's.
     
    Last edited: Aug 2, 2014
  9. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Buy a 12l and a 3l,refill the 3l from the 12,saves you carrying it around everywhere :p
     
  10. Honest Bob

    Honest Bob Big Poster

    Messages:
    3,098
    Likes Received:
    8
    Location:
    Yorkshire.
    Shows how much I know about this subject, did not know I could do that, will have to look into it, as lots of used 3 ltr 300 bar bottles up for sale. Ta for the info. Bob.
     
    Last edited: Aug 2, 2014
  11. Kenbarcon

    Kenbarcon Donator

    Messages:
    3,104
    Likes Received:
    13
    Location:
    Hunmanby, Filey
    Thats what we do over this side of the country. Saves a lot of messing about and as i use the Daystate quick fill adapters on the whip.
    12ltr bottle
    View attachment 100599
    3ltr
    View attachment 100600
    Double ended whip with quick fill adapters.
    View attachment 100601
     
  12. Honest Bob

    Honest Bob Big Poster

    Messages:
    3,098
    Likes Received:
    8
    Location:
    Yorkshire.
    Thank's for that info, just one question, will a refill whip take 300 bar pressure, don't want to have an accident. Atb, Bob.
     
  13. Kenbarcon

    Kenbarcon Donator

    Messages:
    3,104
    Likes Received:
    13
    Location:
    Hunmanby, Filey
    I got my 12ltr bottle and whip from go-dive and yes it will take 300 bar.
     
  14. mattyts

    mattyts Donator

    Messages:
    6,201
    Likes Received:
    163
    Location:
    Yorkshire
    Yea it will,I often have the full pressure of my bottle in the whip,that's how you check the pressure of the bottle.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice