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Nightmare fuel, anyone?

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Comments

  • mikeg2015
    mikeg2015 Member Posts: 1,194
    This is why I have my high limit pressure control wired ahead of the feeder. So 2psi is the max the system would fill before killing the feeder and transformer power. However, you normally don’t wire a operating control this way, but again, on mine it’s a Oh S*** limit only. My system should never go over a couple ounces.

    2psi is 4.6’ so it would fill my header and up to the air vents, but should stop long before any 1st floor radiator vents or even radiator valve stems.

    I have an adjustable DP switch for hi/lo burner control, but it’s not wired up yet since I have never seen my system build any measurable pressure anyway.

    If my boiler floods even above my sight glass, my low pressure range gauge starts reading in ounces.


    Just a thought, you could wire a pressure switch installed below the water line for maybe 2 psi to kill power to the feeder if you can set hte operating control low enough.
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2019
    All though the B2 bomber (flying wing concept from the 40’s) flys. It can only do so through sophisticated computer software.

    The concept years many decades ago for the flying wing needed to wait for technology to catch up to make it feasible.

    The point being computer software compensated for the human elements short comings to efficiently fly that aerodynamic platform. Not just the flying wing either.
  • Gordy
    Gordy Member Posts: 9,546
    The 737 max was an aerodynamic design solely based on the engines adapted to an existing airframe. All to compete with airbus a320....

    The software can only compensate for designs for seen issues.
  • Jamie Hall
    Jamie Hall Member Posts: 24,499
    Gordy said:

    ...
    The point being computer software compensated for the human elements short comings to efficiently fly that aerodynamic platform. Not just the flying wing either.

    The F-22 is even worse... or better, depending on one's point of view!

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    The Northrop YB-35 was the original "flying wing" heavy bomber. It didn't need computers to fly.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Gordy
    Gordy Member Posts: 9,546
    There were many Northrop YB variants. From prop to jet. The yb 35 could fly, but was plagued with issues in testing. To be airworthy a design must pass all facets of rigorous military testing. Thus scrapped until technology could make it fly. Jack Northrop got to see it with the B2 before he died at least.

    The Germans were on to the flying wing design long before Northrop. It didn’t fly well either.
  • Jamie Hall
    Jamie Hall Member Posts: 24,499
    That was a flat-out strange period in aircraft design. No one -- no one -- really knew what was the best way to go. The B-36 had big problems (ultimately solved, sort of, by adding 4 jet engines -- hence "six turning and four burning, boss"). The B-35 had propulsion problems -- and wasn't as stable a platform as the bomber folks wanted. And so on. And then, out of the clear blue sky, came... the B-47, which promptly made most of the discussion irrelevant, and which was closely followed by the B-52, which is still with us.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2019
    My point is with computer software GIGO applies. If the designer doesn’t know, predict,or understand all the variables the program must encompass its GIGO.
  • Gordy
    Gordy Member Posts: 9,546
    The golden years as Yeager put it. Right after WW2. Now there’s a man that has seen it all. Still alive at 96.

    Everyone lacked data. The X1’s primary goal was to gather data Since wind tunnels at the time were useless beyond Mach .94. Where everything goes to hell in a hand basket.
  • Steamhead
    Steamhead Member Posts: 17,312
    mikeg2015 said:

    This is why I have my high limit pressure control wired ahead of the feeder. So 2psi is the max the system would fill before killing the feeder and transformer power. However, you normally don’t wire a operating control this way, but again, on mine it’s a Oh S*** limit only.

    We wire all our secondary pressure controls this way. Secondary LWCO first, then secondary Pressuretrol, primary LWCO (to which feeder is connected) and primary pressure control (Pressuretrol or Vaporstat). This also gives us a logical troubleshooting sequence if the boiler doesn't start.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • ethicalpaul
    ethicalpaul Member Posts: 6,387
    These are all in series, right? So it doesn’t matter what the order is operationally, does it? If one says no, nothing is flowing across any of them

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • Jamie Hall
    Jamie Hall Member Posts: 24,499
    @Steamhead -- what impact, if any, does killing power that way have on the burner? Thinking about post-purge.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steamhead
    Steamhead Member Posts: 17,312
    edited December 2019

    These are all in series, right? So it doesn’t matter what the order is operationally, does it? If one says no, nothing is flowing across any of them

    Correct- but here's why:

    In the scenario I described, and assuming the LWCOs are probe type:

    1- If there is no power to either LWCO, you check for a circuit breaker or switch that is turned off;

    2- If the secondary LWCO has power and is not tripped, but the primary LWCO does not, check the secondary pressure control and reset if needed;

    3- If both LWCOs have power and are not tripped, either the primary pressure control is stuck in the open position, or the burner safety control has tripped, or there is some other reason the burner isn't starting.

    So, you use the hookup sequence to help you quickly diagnose a no-heat call.

    @Steamhead -- what impact, if any, does killing power that way have on the burner? Thinking about post-purge.

    If one of the secondary safeties trips, that's an urgent situation and it should interrupt all power to the burner (or burner control circuit, on larger units). The primary safeties would only shut off the "limit" lead to the burner, to allow post-purge under normal operation.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    ethicalpaul
  • BobC
    BobC Member Posts: 5,495
    @ChrisJ China is building a liquid fueled reactor as we speak and India is well on the way to building one.

    Until the last few years most rectors were designed if not built in the US so they all were of the same basic design we have used for the last 50 years. The solid fuel pellet makers did everything they could (and it was a lot) to make sure those lucrative orders for fuel pellets kept rolling in. Nothing like bags of cash to get what you want.

    The regulation process makes it very hard to get a different design looked at, never mind built in this country and that is why most development takes place outside the US.

    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
  • Lard
    Lard Member Posts: 115
    I have had the same fear of runaway feedwater. In my case, there is a boiler feed tank/pump unit with a float for makeup water. If the float sticks/the valve goes kaput, it will simply barf out of the overflow into the sump pit—no problem!
    The failure would be a welded contactor for the feed pump or a stuck float in the M-M 150. The 150 has the mercury switches rather than the snap switches so I am not worried about those sticking.
    The 150 is scraped out yearly for safety’s sake, but things could still happen (waterlogged float, would trigger the LWCO switch but force the pump on for eternity). My belief is that the contactor is the most failure-prone piece of my particular feed system.
    I see them weld closed all the time on the CNC equipment I work with- usually on 480v coolant or hydraulic pump controls with high inrush current. Cooked oil, cooked seals or massive coolant spills ensue... they are captive contacts, so if one phase welds, all three stay on— keeping the thermal overload happy. Sure, we monitor the hydraulic oil temperature, coolant levels, and pressures, but all that does is prompt the PLC to shut off all 24v control power and the servo drives—and throw a fault/maybe sound an alarm (if it doesn’t have a rag stuffed in the buzzer)- all while the pump hums away releasing chaos upon the world. The main disconnect is the only way to stop the madness.

    As with the runaway burner mentioned earlier, once a contactor welds the mains feed on to a device, the last line of automatic control has been compromised. Human intervention is the only control left (and that has many failures too, unfortunately).
  • Lard
    Lard Member Posts: 115
    A certain large automotive company I deal with has invested a lot of time and money into detecting valve failures. Metalworking fluid (“coolant”) is a hazmat, so spills are a big deal. Every critical coolant supply valve is doubled, with a pressure switch between the valves to monitor pressure drop and rise. Every eight hours the PLC runs a test sequence to verify complete closure and operation of the valves. The valve actuators have analog position sensors (a potentiometer) to monitor butterfly position.

    They still have spills.
  • mikeg2015
    mikeg2015 Member Posts: 1,194
    ... other option would a
    Gordy said:

    The 737 max was an aerodynamic design solely based on the engines adapted to an existing airframe. All to compete with airbus a320....



    The software can only compensate for designs for seen issues.

    That’s a over simplification. The purpose of the software was not because it was unstable or handled poorly, it’s because is certain specific situations it responded differently that the existing 737-700. The purpose was only to make it “feel” or react more similar to the 737-700 to avoid a new type rating requirement. A similar system was used on the KC-46.

    It flew just fine without the MCAS but in near stall, high throttle and high angle of attack conditions and further increase in throttle caused a more aggressive pitch up condition, so the FAA wanted a system to make it behave more like the older 737.

    A better analogy might be a system that adjusts the throttle response on a car so the a naturally aspirated engine responded the same as a turbocharged engine.
  • Gordy
    Gordy Member Posts: 9,546
    @mikeg2015 didn’t want to get that deep, but in the end the MCAS was installed to compensate for design deficiencies. What’s worse is the MCAS sensors, and programming made the situation deadly. Boeing is paying dearly now..
  • Jamie Hall
    Jamie Hall Member Posts: 24,499
    Whoa there, folks. The 737 MAX MCAS system was -- and is -- designed and intended to make the aircraft feel more like the 737 NG series -- as @mikeg2015 said, to avoid having to have new type rating -- which is a big deal. However... it was dependent on a single angle of attack sensor (oops) with no logic to correlate power, airspeed, g force and AOA. Leading to a situation where a sensor problem could cause it to command a pitch trim down. That has been corrected (a similar problem, though dependent on two sensors failing rather than just one, exists in Airbus designs, and was responsible for the loss of one over the South Atlantic a few years ago. This has not been corrected to date).

    Now it could be argued -- as @Gordy has -- that this amounts to a design deficiency. I beg to differ. A design characteristic, yes -- two big turbofans located below the centre of drag are going to cause a pitch up when they spool up. Can't get around that one, unless the thrust centerline is aligned with the centre of drag and the vertical position of the centre of gravity. This has, however, been a characteristic of all turbine aircraft with the engines in nacelles below the wing. The effect is just bigger. (incidentally, one could equally well argue that the tendency for an F4U or Spitfire or Mustang to go rocketing off into the shrubbery if you advance the throttle too fast on takeoff is a design defect. No. It's a characteristic, and can't be avoided, but a competent pilot can cope -- obviously). Now there are two ways to handle such characteristics -- and those who know me will know which I prefer. First, make sure that the pilots are adequately trained and experienced to manage the characteristic. This is not a big deal, really, but does mean that relatively low time pilots may not be the best choice. Second, use software in the system so that less well experienced pilots don't get into trouble, which is the choice -- to meet customer demand -- that Boeing (and Airbus -- if anything, Airbus is worse; but they've only crashed one that way so far) have made. Boeing also, to their credit, provided an easy way to disable the software if it misbehaved (Airbus not so much -- if HAL goes ape, you're just along for the ride). The software did misbehave. Unfortunately, the pilots were not even adequately trained to recognize the problem and push the switch (it's on the left side of the yoke, on top) to disable the software and fly the plane by hand.

    So where is the blame to be allotted? Boeing, for designing and installing software which could misbehave? The regulators, for not seeing a situation where the software could misbehave and the pilots would be too poorly trained to cope? The airlines, for hiring pilots who hadn't enough experience and training? Newton, for explaining why a trim change would occur?

    A lawyer would say Boeing, of course, since it has the deepest pockets. The press would also pick Boeing -- you can't attack the regulators in a tweet, and attacking the airlines or pilots would not be PC). I would say let's not blame anybody, but take the lessons learned and go forward and try to do better.

    And yes, for the curious, I have flown an F4U, and trust me -- you'd better know what you're doing.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChrisJ
    ChrisJ Member Posts: 16,230
    Hmm
    :)
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    Hap_Hazzardratioethicalpaul
  • Gordy
    Gordy Member Posts: 9,546
    @Jamie Hall your comparison to military aircraft characteristics Verses civilian is admirable.

    However military airplanes, and pilots are subject to quite a different scope than civilian aircraft, and pilots. Those military pilots that spilled into the civilian airline industry are becoming thin. Military pilots spend a lot more time, and focus on aircraft systems than civilian pilots. They know the platform inside out, and are ready for those design quirks when the situation could arise.

    This mind set is how Chuck Yeager contributes to his successes in test piloting hundreds of new military designs in his career.

    The movie such as the right stuff, and autobiography do not do him justice, until you watch some of his interviews. He goes into vivid detail with some of his near death situations with different test piloting situations. His complete knowledge of the aircraft, and its systems were paramount.

    That all goes away when computers, And simulators take the drivers seat in training pilots.

    I suppose a true aircraft design flaw would be the Issue of tail falling off the Beechcraft Bonanza in certain scenarios.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Chuck also has a tendency to embellish.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2019
    He earned that right.

    The details of certain events in his interviews were far from embellished. They are on YouTube. You need to have a fair amount of knowledge of aviation to understand his explanations on what happened in certain events.