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  1. #21
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    In order to make an informed choice you need first to specify your requirement parameters. Size of compressor, number of required fills between
    filter change, duration, life expectancy, ambient temperature conditions and purity all have bearing on the size and diameter of filter cartridge
    and filter chemical composition. While the recreational scuba dive shops have not yet faced this responsibility and remain happy to keep you ignorant
    with this "double filtration" nonsence like its a cheap larger.

    To begin.

    1. All breathing air scuba compressors require filtration to pass an air purity standard of BS12021
    2. What they don’t have to do is tell you the point at which the filter fails. Or have in place a visual indicator to monitor the filters gradual decline
    monitored in real time during the life of the filter chemical cartridge, or in the event a failure say you forget to bleed the water content in the separator towers
    3. Presently for breathing air the maximum level of oil contaminate is 0.5 mg/m3

    The standard for Breathing Air is BS12021
    Carbon Dioxide CO2 less than 500 ppm
    Carbon Monoxide CO up to 5 ppm
    Oil up to 0.5 mg/M3
    Water less than 25mg/m3

    By contrast for Nitrox production there is a dramatic lowering of two specific contents in the gas production and one additional component to test for
    First the allowable water content is reduced from 25mg/m3 for breathing air to 15mg/m3 for nitrox
    Also the allowable oil carry over from 0.5Mg/m3 for breathing air to 0.1mg/m3 for nitrox production
    So the fist kicker is you additional filter needs to be capable of reducing both water and oil.
    Then in addition the total volatile hydrocarbons vapour or gas as methane equivalent needs to be less than 30 ml/m3

    Carbon Monoxide CO reduced to 3 ppm
    Oil reduced to 0.1mg/m3 so another required reduction
    Water also reduced to 15mg/m3 another reduction is required

    So this additional filter needs to process a reduction of three components and address this one additional component.
    Now if you also wish to consider air purity testing presently the standard states the frequency of the test should be every 3 months
    (this is a penalty for using oil lubricated compresses) unless deemed “Oil Free” by the original equipment manufacturer.

    Now how the heck these junk personal filters are going to help you here I'm not sure, but also as recreational divers your choice of suggesest suppliers
    don’t know either and don’t care to inform you.

    Given enough time and enough contamination all filters by there very nature fail. Aim to understand this and the requiremnt and the process involved.
    It just aint scuba slop hanging on the slatwall.
    Last edited by iain/hsm; 24-05-2019 at 10:49 AM.

  2. #22
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    Or you could just change the filter as per the manufacturers specified hours and then there's no need for worrying about a second inline filter. Fyi, with the Coltri MCH6 its a relatively easy job to fit the recommended Coltri hour meter on top of the switch box.

  3. #23
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    Quote Originally Posted by iain/hsm View Post
    In order to make an informed choice you need first to specify your requirement parameters. Size of compressor, number of required fills between
    filter change, duration, life expectancy, ambient temperature conditions and purity all have bearing on the size and diameter of filter cartridge
    and filter chemical composition. While the recreational scuba dive shops have not yet faced this responsibility and remain happy to keep you ignorant
    with this "double filtration" nonsence like its a cheap larger.

    To begin.

    1. All breathing air scuba compressors require filtration to pass an air purity standard of BS12021
    2. What they don’t have to do is tell you the point at which the filter fails. Or have in place a visual indicator to monitor the filters gradual decline
    monitored in real time during the life of the filter chemical cartridge, or in the event a failure say you forget to bleed the water content in the separator towers
    3. Presently for breathing air the maximum level of oil contaminate is 0.5 mg/m3

    The standard for Breathing Air is BS12021
    Carbon Dioxide CO2 less than 500 ppm
    Carbon Monoxide CO up to 5 ppm
    Oil up to 0.5 mg/M3
    Water less than 25mg/m3

    By contrast for Nitrox production there is a dramatic lowering of two specific contents in the gas production and one additional component to test for
    First the allowable water content is reduced from 25mg/m3 for breathing air to 15mg/m3 for nitrox
    Also the allowable oil carry over from 0.5Mg/m3 for breathing air to 0.1mg/m3 for nitrox production
    So the fist kicker is you additional filter needs to be capable of reducing both water and oil.
    Then in addition the total volatile hydrocarbons vapour or gas as methane equivalent needs to be less than 30 ml/m3

    Carbon Monoxide CO reduced to 3 ppm
    Oil reduced to 0.1mg/m3 so another required reduction
    Water also reduced to 15mg/m3 another reduction is required

    So this additional filter needs to process a reduction of three components and address this one additional component.
    Now if you also wish to consider air purity testing presently the standard states the frequency of the test should be every 3 months
    (this is a penalty for using oil lubricated compresses) unless deemed “Oil Free” by the original equipment manufacturer.

    Now how the heck these junk personal filters are going to help you here I'm not sure, but also as recreational divers your choice of suggesest suppliers
    don’t know either and don’t care to inform you.

    Given enough time and enough contamination all filters by there very nature fail. Aim to understand this and the requiremnt and the process involved.
    It just aint scuba slop hanging on the slatwall.
    Iain you have explained before about visual inline indicators to tell you of possible contaminants could you please re post this information as I am sure it would benefit my clubs compressor.

    Graham

  4. #24
    Established TDF Member Steve C's Avatar
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    Quote Originally Posted by bottle maker View Post
    Iain you have explained before about visual inline indicators to tell you of possible contaminants could you please re post this information as I am sure it would benefit my clubs compressor.

    Graham
    Graham

    I found these: Nuvair Visual Indicators

  5. #25
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    Quote Originally Posted by cathal View Post
    Or you could just change the filter as per the manufacturers specified hours and then there's no need for worrying about a second inline filter. Fyi, with the Coltri MCH6 its a relatively easy job to fit the recommended Coltri hour meter on top of the switch box.
    Cathal. Sure, but we all do that already on our primary filter for Breathing Air. Changing the cartridge at or before the specific manufacturer suggested running hours. However the subject we are talking about is secondary filtration. You need now to also consider the additional means your going to employ
    to ensure that the tighter purity requirements listed above meet the higher purity standard required that you don’t get with Breathing Air filter standards.

    If however your suggestion of “Then there’s no need for worrying” you imply that the existing Breathing Air standard is adequate.
    Then your are simply ignorant of the implications.

    Further as for you fitting an after market hour meter on your Coltri MCH6 suggestion.
    Any competent supplier selling a compressor for Breathing Air applications should provide an hour meter into the build spec as standard.
    You could help the post however by telling us all how much you paid for this simple fix Coltri hour meter.
    Last edited by iain/hsm; 26-05-2019 at 10:02 AM.

  6. #26
    Established TDF Member
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    Quote Originally Posted by bottle maker View Post
    Iain you have explained before about visual inline indicators to tell you of possible contaminants could you please re post this information as I am sure it would benefit my clubs compressor.

    Graham
    I cannot recommend these High Pressure In line visual indicators enough. For years we have tried to get them incorporated into every compressor used for breathing gasses.
    Yet in the UK you can count on one hand the number of visual indicators used by local dive shops even less used by local clubs. Yet you have to go to America and they are all the rage. Maybe I should do a TDF special price like we did with the Christo-Lube MCG111 or start a web site and buy lot's of slat wall

    Engineered to the highest mechanical standard with a 414 bar working pressure and a 4:1 Safety factor to meet UK offshore requirements. A visual viewport capable of withstanding 30,000 psi pressure and a fail safe design that extrudes the case o-ring at the 2068 Bar pressure point of failure. Using a super hardened Alloy, a military grade hard anodising
    and a machined viewport that ensures crystal clear optical clarity, With no moving parts and Viton aircraft grade O-rings with compound number, and cure date of manufacture.

    Who can resist such an engineering feat. Everyone apparently (apart from the Yanks.)
    But they are not liked by the compressor manufacturers who prefer to sell you disposable throw away cartridges, bit like computer ink jet printer cartridges I guess except they last longer.

    One of the big advantages I used to claim using an oil free compressor design was getting 150 to 200
    hours life out of the repack able filter cartridge that oil lube units get only a 40 or 50 hour filter life.

    1. Was the fact oil free does not clog up the filter medium with a oil film
    2, Was the fact you didnít need activated carbon for the oil so could use more MS chemical in the pack
    3. Was the additional cooling Dp factor using oil free as opposed to a hot oil lubricated bath.
    4. Was using medical grade non carcinogetic molecular sieve, than imported junk from China with up to 30% inert build filler and binder (the brown colour)
    4. But another big factor was using the in line visual indicator and monitoring performance in real time allowing the user to change the chemical or cartridge
    when it was needed and not before (or too late with the clock it and hope version.)

    They have sold in the UK at £68 inc UK mainland delivery for the last 20 years with a 1/4NPT both ends, or 1/4 NPT one end 9/16-18 UNF thread the other or 9/16 thread each end to suit the Bauer P40 and P60 range.

    The visual indicator is included in the package but it is different from the American one shown.
    We offer a multi range indicator showing both 10/20/30% relative humidity or for the primary filter a 20/40/60% RH alternative for bulk primary rough filtration of multiple stacks.

    Both of these UK indicator cards last 2 to 5 years and cost £10 to replace

    Now that American website replacement indicator card isnít from the UK IMHO its a single indicator set at 40% RH and itís a "typo" that they claim 10%

    Further we stopped suppling the old CO carbon monoxide indicator card 15 years ago in favour of electronic versions as the original passive colour change CO chemical card indicator only indicates at 50ppm by which time your pretty much a gonna IMHO.

  7. #27
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    Iain, can I get a replacement 10/20/30% indicator from you?
    Dave


    Sent from my iPhone using Tapatalk

  8. #28
    Established TDF Member
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    Quote Originally Posted by Dave1w View Post
    Iain, can I get a replacement 10/20/30% indicator from you?
    Dave Sent from my iPhone using Tapatalk
    Er You want to buy SPARE PARTS !!!!!
    Isnt this the point when I tell you its against Health and Safety rules and we cannot sell you a spare part as it's for critical life support equipment.
    And I send you to have it oxygen cleaned every year by your local dive shop with an IDEST certificate on the wall, By an oxygen cleaned technician.
    Then fellow divers pipe in and suggest you can buy them at inflated prices from dive shops in Germany. Or maybe I'm just dreaming this up and thinking Apeks

    No problem private email your shipping address, Oh and no charge.

    Cant have our forum overwatcher thinking I'm making my fortune from internet sales of compressor parts and damaging The Great British Dive Shop

  9. #29
    M.D., Beaver Sports (Yorks) Ltd
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    Quote Originally Posted by graham_hk View Post
    How would you fail an 02 clean?

    I have heard that these personal filters arenít worth it, I have also heard that regular filter changes on a well maintained Bauer and thereís not Need for an additional filter. But itís all here say and nobody qualified will give a proper answer ...
    Graham, Beaver's wording on their website fully backs up your statement and Beaver totally agree with you, they are supplied for use when that may not be the case!! Apart from many years ago, someone using one with 100% pure oxygen, which it should not be used for as stated in the instructions and literally blowing it up, we have never had a single negative comment about them, so must presume the thousands of users over the last 20 years or so are happy. The recently introduced cartridge type filter media change has made them much easier to service. Additional information can be found by scrolling down the page to them here http://www.beaversports.co.uk/Catalo...gory/63?page=2

    "Personal Air Filter with 230 BAR A-Clamp inlet and outlet. Used to filter air between compressor & cylinder, very useful if you are into keeping your cylinders in an O2 clean status and are not quite sure of the quality of the gas you might receive at various charging sources. Quickly and easily maintained, using our compact and convenient PAF KIT - Personal Air Filter Service Kit. Reduces the risk of cylinder contamination from air fills and ensures a longer cylinder life. Can be used with Nitrox if O2 cleaned."

  10. #30
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    ...
    Last edited by graham_hk; 29-11-2020 at 01:42 PM.


 
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