Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)
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Mike's reference is a good one, but this one is specific to North American freight brakes:
On October 10, 2020 at 10:45 AM Mike Conder <vulturenest1@...> wrote:
BTW, great description of the triple valve is here:
Sort of, I think. The injector uses internal venturis powered by steam. The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler. Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)
Mike Conder, mechanical engineer
On Oct 10, 2020, at 09:41, johnny graybeal <
> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.
What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...
From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.
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