Perhaps a stupid idea (flood coolant)
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 39
  1. #1
    Join Date
    Oct 2017
    Country
    FINLAND
    Posts
    550
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    167

    Default Perhaps a stupid idea (flood coolant)

    I'm thinking it's unworkable because I haven't been able to google someone else doing it. I've been thinking of flood coolant and bacteria problems. Seems to be a merry go around with no real ideal solution, oil skimmers, running aerators, swapping the coolant often, using bleach (contested) or other biocides (possible other side effects) and maybe something else that I've missed. Now what I was thinking, why not install a heating coil in the coolant container and set it to heat the flood coolant to say 75C one day every week, perhaps during night so it won't bother anyone.

    I thought of this because our heat pump in our house has a program that weekly increases the water temperature to prevent legionella from forming in the reservoirs. Also pasteruized a bunch of apple juice earlier. Thought maybe this could be adapted to flood coolant as well, at 75C most bacteria should be well dead. Problems I see would be if the temperatures in that range might affect the composition of the coolant, and the increased evaporation of such a process, though if you keep the coolant in a well sealed container it shouldn't be too bad, the built in sump might not be good enough for this, and hot water and moisture would make rust issues worse, so a separate container is probably better, maybe built from stainless.

    Anyway is there anything obvious I am overlooking that makes this not work, because if it worked I feel someone would have come up with it already...

  2. #2
    Join Date
    Jan 2005
    Country
    CANADA
    State/Province
    Saskatchewan
    Posts
    10,222
    Post Thanks / Like
    Likes (Given)
    1392
    Likes (Received)
    3674

    Default

    I don't know, but the dead crap from the last batch of bugs makes good food for the next batch.

  3. #3
    Join Date
    Jan 2014
    Location
    Temecula, Ca
    Posts
    2,847
    Post Thanks / Like
    Likes (Given)
    1277
    Likes (Received)
    3680

    Default

    Quote Originally Posted by DennisCA View Post

    Anyway is there anything obvious I am overlooking that makes this not work, because if it worked I feel someone would have come up with it already...
    Ya, use a good quality coolant. (No, not Blaser) Problem goes away

  4. Likes mhajicek liked this post
  5. #4
    Join Date
    Dec 2012
    Location
    Se Ma USA
    Posts
    1,497
    Post Thanks / Like
    Likes (Given)
    115
    Likes (Received)
    840

    Default

    Quote Originally Posted by Larry Dickman View Post
    Ya, use a good quality coolant. (No, not Blaser) Problem goes away
    Blaser coolant in my VMC is 17 years old? Machine gets used maybe once a month. Sometimes it gets a tiny smell that goes away after a few hours. I add water and fresh coolant with every use. Lathe 16 years and turns 99.9 % brass. Coolant has greenish tinge to it. Never smells and often has an oil film over it.
    I guess it depends on how clean the parts are going in to the machine. The Band Aide Lenox coolant in the bandsaw went bad from all of the crap the steel was covered with. All blanks were wiped down real good prior to machining.

  6. #5
    Join Date
    Dec 2008
    Location
    IL/WI border
    Posts
    3,210
    Post Thanks / Like
    Likes (Given)
    1016
    Likes (Received)
    937

    Default

    Quote Originally Posted by DennisCA View Post
    I'm thinking it's unworkable because I haven't been able to google someone else doing it. I've been thinking of flood coolant and bacteria problems. Seems to be a merry go around with no real ideal solution, oil skimmers, running aerators, swapping the coolant often, using bleach (contested) or other biocides (possible other side effects) and maybe something else that I've missed. Now what I was thinking, why not install a heating coil in the coolant container and set it to heat the flood coolant to say 75C one day every week, perhaps during night so it won't bother anyone.
    I think this may work. Coolant may get pretty hot at the part being machined, yet it is re-used over and over again. It means it has some tolerance to being reheated.

    I don't know how effective 75C will be in killing targeted bacteria. Maybe you'll need higher temperatures. I guess you can try it on a small batch and choose the lowest effective temperature.

  7. #6
    Join Date
    Oct 2017
    Country
    FINLAND
    Posts
    550
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    167

    Default

    Quote Originally Posted by HuFlungDung View Post
    I don't know, but the dead crap from the last batch of bugs makes good food for the next batch.
    Yeah that is an unknown factor here, how long will it take the next infestation to reach problematic levels. I suspect this depends on usage and temperature in the shop. If you don't use it often, then once it's been "pasteurized" it shouldn't become reinfected until it's used again and fresh bacteria are pulled into the system, then it depends on temperature in the shop, is a few days or a week enough to cause issues, I don't know, in that case the frequency needs to be increased. My shop is only 10 celcius or so during the winter months so things would grow slowly.

    I think this solution might be better suited for those who might let their coolant sit for longer periods between usage, and that is the demographic it seems to have been most difficult to find an acceptable solution for.


    Quote Originally Posted by MichaelP View Post
    I think this may work. Coolant may get pretty hot at the part being machined, yet it is re-used over and over again. It means it has some tolerance to being reheated.

    I don't know how effective 75C will be in killing targeted bacteria. Maybe you'll need higher temperatures. I guess you can try it on a small batch and choose the lowest effective temperature.
    I was thinking along the same lines myself, but I have nothing concrete to go on, just the same idea as to why it ought to work. And 75C is almost 170F, it should kill all the bacteria I believe are likely to be found in this situation.

  8. #7
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    27,235
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8490

    Default

    Quote Originally Posted by DennisCA View Post
    Anyway is there anything obvious I am overlooking that makes this not work, because if it worked I feel someone would have come up with it already...
    Big Universe. Didja know.. there was once a pigment used in wallpaper. Lovely colour called "Scheeles Green".

    Scheele's Green - Wikipedia

    Our Uni Chem prof told us WHY it had fallen out of use.

    Seems there exists a bug that eats of the Arsenic compounds, releasing Arsine gas, Which pizens folks. Slowly. Very. Very DAMNED slowly.

    My advice if you are not keen on the not so terribly-dificult-after-all monitoring, care, and maintenance of emulsion coolants? (Ho Cut, here..).

    Just consider use of a "neat oil" instead.

    Bugs live on that as well. Eventually. They are just slower-growing and easier to control than bugs as have the blessing of water to-hand.

    The challenge, y'see is that "once in a while" smallholder/retiree/hobby users have issues that "every DAY" users keeping a machine-tool busy at least half a shift or so don't really have the same level of worry about.

    Tending to coolant is just part of the larger picture, covered in the overheads of a revenue shop, and no big deal. The effect is has on tool-life, throughput, and surface of the parts or cleanup of the parts is far the more important.
    Last edited by thermite; 11-10-2019 at 09:39 AM.

  9. Likes PegroProX440 liked this post
  10. #8
    Join Date
    Dec 2008
    Country
    UNITED STATES
    State/Province
    New York
    Posts
    10,099
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2622

    Default

    maybe get coolant bacteria dont like. often coolant ph is 9 or 10 and a device like aquarium air pump bubbles air through it all day long. maybe change coolant once a year cause it gets oil mixed in and fine dust or sand like chips accumulate at the bottom
    .
    most places try to control coolant temp +/-1 degree F for part size control. obviously even 2 or more degree temp difference can cause problems if trying to hold <.0003" tolerances per 40"

  11. #9
    Join Date
    Dec 2012
    Location
    Se Ma USA
    Posts
    1,497
    Post Thanks / Like
    Likes (Given)
    115
    Likes (Received)
    840

    Default

    Quote Originally Posted by DMF_TomB View Post
    maybe get coolant bacteria dont like. often coolant ph is 9 or 10 and a device like aquarium air pump bubbles air through it all day long. maybe change coolant once a year cause it gets oil mixed in and fine dust or sand like chips accumulate at the bottom
    .
    most places try to control coolant temp +/-1 degree F for part size control. obviously even 2 or more degree temp difference can cause problems if trying to hold <.0003" tolerances per 40"
    I made a small air flat coil of .125 ID plastic hose and zip tied it to a metal frame. Coil had pin holes in it. Sunk in the bottom of a open barrel of old coolant to evaporate the water content. Loads of tiny bubbles. After 20 min there was a fog over the barrel of old coolant mist. That ended that experiment. Don't want to breath that stuff.

  12. #10
    Join Date
    Jul 2011
    Location
    East Yorkshire UK
    Posts
    356
    Post Thanks / Like
    Likes (Given)
    822
    Likes (Received)
    293

    Default

    I don't think I could sleep nights with a heater immersed in an oil/water mix coming on in the middle if the night!

  13. #11
    Join Date
    Aug 2005
    Location
    Raymond , CA
    Posts
    259
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    176

    Default

    Quote Originally Posted by DennisCA View Post
    I'm thinking it's unworkable because I haven't been able to google someone else doing it. I've been thinking of flood coolant and bacteria problems. Seems to be a merry go around with no real ideal solution, oil skimmers, running aerators, swapping the coolant often, using bleach (contested) or other biocides (possible other side effects) and maybe something else that I've missed. Now what I was thinking, why not install a heating coil in the coolant container and set it to heat the flood coolant to say 75C one day every week, perhaps during night so it won't bother anyone.

    .
    Flash Pasteurization occurs at 71 deg C for a 15 second duration. Bulk Pasteurization occurs at 66 deg C for a duration of 30 minutes Pasteurization kills many but not all of the food borne bacteria. It does not kill the endospores that bacteria form when conditions are not favorable to growth.

    Sterilization occurs at 121 deg C for 15 minutes. The heat will kill all bacteria and their endospores.

    The effectiveness of the heat is logarithmic with temperature and time. The bacteria population can be reduced by approximately a factor of ten by increasing the process temperature by 10 deg C. The factor of ten reduction can also be accomplished by doubling the contact time at a given temperature.

    Oxygen does kill bacteria of the genus Clostridium. This includes botuliium and perfringens These are associated with food poisoning. Pasteurization for these bacteria has a short term effect. The bacteria rapidly grow after cooking once the temperature drops below 40 deg C.

    The use of aerators in machine tool sumps slows down the fermentation process and smell of the byproducts of some of the bacteria. It does not kill them with the one exception mentioned above. Sewage treatment plants use aeration in the secondary treatment process to encourage the bacteria to grow in order to consume organic material contained in the water. The same process is occurring in the machine tool sump.

    The coolant sump can be flash Pasteurized at the end of the work shift by draining the sump with a 1 gallon/minute metering pump and running the fluid through a 20 KW tankless water heater into a insulated storage tank. The 20 kw heater will perform the flash Pasteurization and the insulted tank will continue the job by bulk Pasteurization at a lower temperature but for a much longer time. After many Pasteurization cycles the coolant will contain bacteria that thrive at high temperatures.

    Heating the machine tool sump to achieve Pasteurization will not be practical. The heat loss is too high, there are too many places for the bacteria to hide, and the sump is open to the shop air. The bacteria population would recover within 12 hours. Bacteria populations can double in size every 30 minutes.


    Raising the temperature of 20 gallons of water based coolant by 60 deg C (140 deg F) requires 6.7 Kw-hr of electricity. In California that would cost about 2 dollars. In other parts of the country or maybe in Finland it would cost about 70 cents.

  14. #12
    Join Date
    Sep 2010
    Location
    Oklahoma City, OK
    Posts
    4,300
    Post Thanks / Like
    Likes (Given)
    746
    Likes (Received)
    1792

    Default

    2 thoughts-

    1) a cheap sous vide device would be perfect for this. It's got temp/time control, stainless construction and mine is even wi-fi enabled.

    2) I wonder if a UV solution exists to kill bacteria?

    Sent from my SM-G973U using Tapatalk

  15. #13
    Join Date
    Dec 2008
    Location
    IL/WI border
    Posts
    3,210
    Post Thanks / Like
    Likes (Given)
    1016
    Likes (Received)
    937

    Default

    Quote Originally Posted by Cole2534 View Post
    I wonder if a UV solution exists to kill bacteria?
    It does, but for clear liquids like water. Even with water UV gets attenuated rapidly. With non-transparent liquids, UV will affect only a tiny layer immediately surrounding the UV source.

  16. #14
    Join Date
    Oct 2017
    Country
    FINLAND
    Posts
    550
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    167

    Default

    I work not with machining but at a place that builds spas / saunas / hot tubs and we do sell a UV sterilizer to help with the water filtration, lets you cut down on chemical usage, but as was mentioned it only works with clear liquids.

    At any rate I am planning to build or find a stainless tank I can use to keep coolant in regardless, I don't think I want to use the sump in the base of my FP2 again after cleaning it out, and similar for the original non stainless tank in my lathe.

    I think a single tank to serve both machines is what I will do, it has advantages even if this "pasteurizing" thing doesn't pan out. I can then figure about trying the heating experiment or not. The sous vide equipment sounds interesting, I was thinking of a slow cooker myself.

  17. #15
    Join Date
    Oct 2017
    Country
    FINLAND
    Posts
    550
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    167

    Default

    And as I work at a spa place I do know one or two things about water hygiene and chemicals. I don't like the idea of chlorine because it can remain in the water for a long time in the form of chloramines. They can irritate your eyes and lungs and are responsible for the chlorine smell at pools.

    I also know we have some chlorine free methods of water disinfection, like active oxygen based ones, might be worth a try too, but all our products are meant for hot water spas and tubs so I'd still need to keep the coolant at 25-35 Celsius for it to be most effective so in that case I'd need some kinda heating arrangement anyway. We have a combi-tab that does active oxygen and some other stuff that increases it's efficiency over pure oxygen tabs. Might be worth a try as well, or in conjunction with.

  18. #16
    Join Date
    Mar 2011
    Country
    SWITZERLAND
    Posts
    1,006
    Post Thanks / Like
    Likes (Given)
    122
    Likes (Received)
    413

    Default

    Quote Originally Posted by Scruffy887 View Post
    Lathe 16 years and turns 99.9 % brass. Coolant has greenish tinge to it. Never smells and often has an oil film over it.
    No wonder, brass contains zinc which is bactericidal. Reason why door handles and water taps are made from brass. The greenish tinge is copper sulphate that forms in the moment of machining brass under a coolant containing mineral oil. The sulphur in the oil reacts with copper and air oxygen.

  19. Likes Mcgyver liked this post
  20. #17
    Join Date
    Oct 2017
    Country
    FINLAND
    Posts
    550
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    167

    Default

    One of my earlier ideas was of adding some bits of brass to the sump, but I don't know if it would be effective, or have negative effects on the coolant chemistry.

  21. #18
    Join Date
    Mar 2005
    Location
    Northwest Indiana
    Posts
    4,060
    Post Thanks / Like
    Likes (Given)
    713
    Likes (Received)
    769

    Default

    Silver plated baffles in the coolant tank?

  22. Likes MichaelP liked this post
  23. #19
    Join Date
    Aug 2005
    Location
    Toronto
    Posts
    4,782
    Post Thanks / Like
    Likes (Given)
    3220
    Likes (Received)
    3628

    Default

    Quote Originally Posted by MichaelP View Post
    It does, but for clear liquids like water. Even with water UV gets attenuated rapidly. With non-transparent liquids, UV will affect only a tiny layer immediately surrounding the UV source.

    I was aware of this, but, what about those inline UV water treatment units you'd have on a water supply in a house? The idea was to continually circulating the coolant through it using the pump. I have no idea of the math, but the thought was with enough passes through the UV chamber eventually all the bugs would find themselves momentarily in that thin layer of doom. This is part of a central coolant server project I've been working (for far too bloody long now) that has skimmer, UV and bubbler as well as pump and return filter.

  24. #20
    Join Date
    Apr 2004
    Location
    Modesto, CA USA
    Posts
    6,877
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1147

    Default

    Fish ponds can use uv Sterilizer/filters. It is a sealed unit that water is pumped through barbered fittings. Bleach will cause rust. Any method that is not 100% kill will gradually evolve into resistant organisms that pass through with no ill effects.
    I think for home shops and tools seldom used, pure oil with no water is the best bet. Very slow bacteria growth and no rust.
    For Diesels they make additives to kill mold which can grow in the fuel.
    Bill D.

    No experience with use, just a random link for a biocide.

    Bio Kleen Diesel Fuel Biocide - Power Service


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •