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TWENTY PSIG ISN'T MUCH, RIGHT?

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Jackmartin
Jackmartin Member Posts: 196
Well given the horrible thing that happened in Florida this week, I think we all need some comic relief. Sooooo, I am going to tell you a story that happened to an old phart this week. I have been a journeyman longer than I am sure a lot of the readers of Erins and Dan's website have been alive. I mention that because I know better than to do something so stupid as I did this week. Let me set the scene or the place where stupidity lives.
I was at one of our largest vocational schools and they have a lot of shops that use a huge amount of compressed air for the various shop functions. They have three air hoists for cars alone, not to mention the carpentry shop and all the other areas. We work on Pneumatic controls service because installation of Pneumatics is now really a thing of the past,electronics have taken over. The maintenance guys figured air is air and since I do air controls, I know everything there is to know about, well air! I receive a call; the main air compressor for the building needs some service and since it is slow heating wise, I said sure how hard can it be? I arrive at the school and meet the caretaker, and he explains it is for the main air compressor in the big fan room. They have a twenty horse return air fan and the outside air dampers in this room where it mixes and the supply air fan pulls it in and heats the air as required with a steam coil, plenum mounted. The return air fan is open to the room it blows air into, because the whole room is a really a giant mixing box. Well I am now looking at this giant air compressor and it is a four cylinder thirty horse with a two inch steel pipe coming off for supply to the building. He tells me the tank has not been drained for at least five years it is plugged or something can I fix it? Yup says i, and the fun begins. I ask him to tell the shop people I will have the air down for some time -- he says that is not a problem, it is an inservice day there are no classes. Great. so off I go to work, I survey the scene and I notice the blow down piping is steel so it is immediately apparent the piping is plugged with rust. So, I take a detailed list of what I need and off to the wholesaler to get al the brass pipe and fittings including valves. The plot thickens, I arrive back and the first thing I do is lock out the compressor and shut off the valves supplying the school. I bleed and bleed and I finally get the pressure down to, wait for it --20 PSIG. I open the drain valve on the bottom of the tank and nothing comes out -- just like asking your mother in law for a loan , nothing! Ah ha says I, I guess the gauge is not working there is no pressure left!!!! I have a closer look at the drain on the tank and I see it has very fine mesh screen in it and it is covered in solid crud. I naturally do something I would kick my apprentice around the block for being so stupid ;but, I have over forty years, so I know everything right ---wrong. I get my old, use it for anything ratty old screw driver, and drive it into the mass of crud. This tank is about two hundred gallons and it has not been drained for at least five years. Well, fifty gallons of water at 20 psig coming out of a 3/4 inch hole is going to make a let us say, an impression. I am blasted with water in the face because the drain is of course at the bottom of the tank and luckily ,I have to wear glasses,or I would not be typing this now ,I would be in for eye surgery. I backed away as quickly as I could and the water is coming out like Hurricane Sandy , luckily they store their filters in the room and I management to dive behind them for some protection. I also did not take into consideration there was at least 300 feet of pipe with 20 psig and the main valve did not hold , so this thing blew for a good ten minutes and I looked like a drowned gopher. What to do? I am soaked, totally embarrassed, and if anyone sees me I will never live this down. I go to the truck and as luck would have it, I had a set of Tyvek coveralls I used on another job and of course they have as much crud on them as a barroom floor on a Saturday night. I strip off my pants and shirt and tie them on the discharge of the return air fan grill and I must say, twenty horse power really makes clothes straighten out. The floor is wet, yours truly might as well have gotten out of the shower, and the drain piping for this compressor is lying on the floor. So I start to pipe in this %^$%# drain and finally get it tied into the floor drain. Thankfully, no one came to bother me, because well, there isn't a coffee pot in the fan room so why go there? The clothes being gently wafted by the twenty horse fan were now dry and I have to say unwrinkled, I guess that straight line drying takes the wrinkles out. Just as I was packing up my tools; the caretaker comes to ask how much longer the air would be off. In my best "manly"voice, taking in consideration my private parts are sucked up into my diaphragm, I say I am going to turn it on in about five minutes He sees all the water on the floor and thank heavens for being non observant, he declares there was a lot of snow coming in the outside air dampers they must be plugged up with snow .I of course agreed with him wholeheartedly,"Yep that damned snow!" I got in my service truck and told myself,no one will ever know, that was before the horror in Florida. In the event I can make you laugh for even a second because of my stupidity, it is well worth showing the world what an old fool I am. All the best and lets all pray for the people in Florida. Jack
CLambratioCanuckerkcoppicy78MilanD

Comments

  • BobC
    BobC Member Posts: 5,479
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    Many years ago the company I worked for was having a problem blowing 200 amp fuses in a fused disconnect. The current was not over 200 a but the clips the fuse slid into had lost some of their spring so the contact wasn't as good as it should be and the fuse in that position cooked off.

    Replacing that box would be a bear and we decided to put it off till the winter break when the plant would be closed for a week. In the meantime I had to figure out how to stop the fuse from cooking off.I decided the answer was to put a fuse on the box and that worked fine, the problem is leaving the three phase fusebox open with fan in front of it might just irritate OSHA just a little bit.

    the solution was to put a fan inside the fusebox so the cover could be kept closed. I removed the box cover and had the front of the cover cut away, that steel was replaced with perforated steel and I mounted a fan to thet. The fan was a 120v fan to I ran it to one of the fuse output lugs through a 2a fuse, the other wire went to the neutral lug. i dressed the wire so it wouldn't get caught in the switch mechanism and turned everything on. It seemed to work like a charm. i made a note to myself to come back and tie that wire off so it could never flop it the switch mechanism.

    A week later I had to open that box for another reason, when I was done i shut the door and threw the switch. There was a huge flash and a big bang, that wire that I wired the fan with got caught up in the switch mechanism and trapped between two of the switch blades on the primary side. A14 gauge wire gets very hot when you try and pass 208,000 amps through it (208v / 0.001 ohms). In fact it glows white hot just before it vaporizes. The cover of that box and the fan was coated with a copper sheen that was all that was left of the #14 copper wire.

    All because I didn't go back and tie off that wire, i couldn't see straight for a week. It all proves we are all human and we screw up from time to time, I'm just glad I was the one who closed that switch, I would have felt terrible if somebody else threw that switch.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    MilanDSolid_Fuel_Man
  • ratio
    ratio Member Posts: 3,649
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    In case anyone else has the same problem that @BobC had, they make a thing for that.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,614
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    @ratio Yup, those fuse clips can get tired after a while.
    @BobC , now if I came by with my oil soaked clothes on and threw that switch I woulda been French Fried!!LOL
    CLamb
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    I once did a job wiht large bore PEX for distribution system. Boss was a tight wad and wouldn't hire full time help, so we had to depend upon the local Rent a Bum (Man power) for help. I'd drilled the holes, and instructed the hireawino how I needed the 3/4" PEX run, and went off to do other things.

    Later, he notified me that the PEX had kinked on him during the pull. I told him I'd address it later, and promptly forgot.

    As I was picking up for the week, I looked up and remembered I'd forgotten to relax the kink with a heat gun. So, I grabbed my torch and was feathering the kink with a soft flame to relax the kink, and suddenly, the PEX started blowing up like a balloon. I'd forgotten to take the 100 PSI pressure air test off of it. I dove off the ladder just as the PEX exploded. OK, more of a BANG than an explosion (no flying parts) but it was SO loud, it shook the whole house. The carpenter, who was working up on the 2nd floor came running down the stairs with a look of bewilderment on his face wanting to know if I was OK. I explained my goofy mistake, and proceeded to go back out to the truck for repair couplings, and compressor etc. SO much for getting off early on a Friday afternoon. If I'm not mistaken, the piece of PEX is still floating around on a particular wholesalers desk...somewhere in the Denver area.

    $4!T happens to all of us... More for some than others :smile:

    Work safe out there. You are irreplaceable.

    ME

    There was an error rendering this rich post.

  • BobC
    BobC Member Posts: 5,479
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    @EBEBRATT-Ed i actually did get a few of those within a few days of my "incident", I'm surprised they still make them these days.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge