You think of the old idea of a perfectly stiff rod, which could transfer messages faster than light, simply by twisting it?
(It’s more special relativity, by the way).
For the continuously rotating Coriolis mass flow meter, I’d say the twist we observe in the tubes is explained in the inertial frame as “the water is trying to flow straight, but the tubes are rotating, exerting a force on the water, so the water exerts an equal and opposite force that twists the tubes a bit” (in the rotating frame, of course, the answer is “There’s this Coriolis force that affects things moving towards or away from this special axis, so when the water moves that way the Coriolis force twists the water (and thus the tubes)”).
Exactly.
The technical difficulty of pumping a train of marbles is not the point, it’s understood we’re talking hypotheticals in this case.
As I stated, Coriolis meters don’t handle gas entrainment (the void between the marbles) very well. In other words: Bubbles. Typically in process flows, these problematic bubbles are of the gaseous form, caused by pump cavitation, leaky seals, flashing of liquid to vapor in the pipes, etc. There is nothing to prevent a bubble from being composed of a liquid, E.g. water condensing out in a natural gas line. The point is, Coriolis meters don’t handle two phase measurement very well, and a train of marbles is a good example of a flow comprised of two phases… The marbles, and the medium they are being pumped in (be it air, water, argon, or acetone). In other words: Coriolis meters don’t play well with large aggregate slurries. Make the aggregate composition fine enough, say as in a magnesium hydroxide suspension in water, where the particle size is 20 microns, and they do just fine, because it “sees” but one component, acting in a homogeneous manner, at one density.
They do flow, mass (and mass flow :rolleyes:) exceptionally well, but we often use them simply for flow, reasons being: They are dead nuts accurate, precise, and reliable. No moving parts. No impinging flow restrictions. No routine calibration (there is no calibration necessary, they come from the factory pre-calibrated) and they either work perfectly or they don’t work at all. Compared to all the other types of flowmeters we have to contend with; requiring constant calibration and otherwise constant fiddling with to keep them operational, Coriolis meters are a dream… Expensive, but worth it IMHO.
Exactly. In the old days, to get the stoichiometry in our reactors just so, required waiting on the lab …(tic-toc:eek:) then the calculations for the next charge were done based on their density analysis with fingers crossed that we didn’t loose the reaction (or worse).
Now, our Coriolis meters do it all, instantaneously.
Understood. I feel your pain as it relates to someone citing advertisements… I’ve been where you are now, and I reacted as you have.
It was the best I could do, given the limited time that I’m willing to devote to this. However, the cites I provided weren’t THAT awful, I thought they were mildly instructive… Especially compared to the cites offered to the contrary (none).
I too, live in a hick town, but you thought wrong. Coriolis meters do not live in residential water supplies, irrespective of one’s geographical location. Sorry.
To conclude my rant postings…
It doesn’t bode well for my position that Coriolis meters are actually based upon the Coriolis effect, but…
Many of you have convinced yourselves that there was/is some kind of Coriolis meter that has spinning, twirling, or otherwise… some kind of 360 degree rotating flowtubes in the CONVENTUIAL sense… This is not the case, nor was it ever, at least for the past 42 years.
The rotating animations viewed online are merely an attempt to get one to perceive how the torsional flux in an oscillating tube (with flow going through it) relate to the Coriolis effect.
Sorry if your perception of this “effect” doesn’t fit your limited definition of what is correct, but the fact is… It works.
Maybe there is something going on here that you simply don’t understand. Fancy that!
Oh, I’m sure these devices exist, and work, and have all of the nice properties others are describing. I’m just saying that, whatever the principle is that they’re based on, it can’t be the Coriolis effect if there’s nothing rotating.
Specifically, we ourselves are not rotating … the principle involved has to based on something else.
If fictional centrifugal forces can manifest with fractional rotations, why can’t fictional Coriolis forces also manifest with fractional rotations?
What is a “fractional rotation?” The rate of rotation can be very small – one revolution per year – or it can be quite high – a million revolutions per second. It’s a measurement of angular change.
“Fractional rotation” doesn’t have any meaning. There is no Google cite for it.
Both centrifugal and coriolis force will appear with any non-zero rate of rotation (although, in practice, it might be too small to detect. If you run eastward, you will weigh slightly less than if you run westward…but good luck observing that difference in real practice.)
A fractional rotation is a rotation by an amount less than 2pi radians. Though I’m not clear that the devices even do that.
Clearly we are meant to model the vibrations as a small rotation in one direction, followed by a small rotation in the other over and over again, and imagine the Coriolis forces as switching between those that would be experienced by an apparatus rotating in one direction followed by those for the other direction.
I can’t tell you how glad I am that you brought up the centrifugal force. Let us consider the average centrifuge, As it spins, the centrifugal force is directed outward, providing the more massive particles with greater acceleration in the direction of the force than the less massive particles. So when the lab tech pulls out the sample, it’s graduated based on mass. He’s happy, and doesn’t care one bit the that mass was graduated the exact opposite of what Newton’s 2nd Law predicts.
With our mass flow meters, the Coriolis force is of the right magnitude, who cares if it’s pointed the wrong direction, we still have an accurate mass measurement.
In a centrifuge, the apparatus is applying a centripetal force due to the electromagnetic forces holding the apparatus in it’s solid state (very strong btw). This force is pointed inward provides the more massive particles less acceleration than the less massive particles.
Similarly, in our mass flow meter, it is the apparatus that is providing the force to accelerate the water. We know the amount of force, we measure the acceleration and quickly calculate mass.
Unnecessary details … perhaps … but what is it we’ve been fighting since 1974?
It’s a rotation with an oscillating torque. The inlet and outlet pipes define our axis of rotation.
It’s good to see this conversation has maintained legs, despite early (and continued) foot stomping. This is a very difficult concept to visualize.
Apologies to the OP because this thread was, to some degree, hijacked. Hope your presentation went well.
Sort of like envisioning a single point on an automobile tire rotating in two dimensions… Graphically, it would be depicted as a sine wave… No 360 degree rotation there. But combine that sine with a third dimensional perspective, and viola! 360 degree rotation.
Similarly, envision the tubes in a Coriolis meter that are excited by the drive coils. Keep in mind: They do not oscillate in a PLANAR fashion, they oscillate in an ARC at rest… (TWO dimensional at zero flow).
Combine this with the torsional twist in a FLOW condition (the third dimension over time) and you have 360 degrees of physical rotation relative to the pick up head.
Or so as it has been explained to me by factory reps… Anyone have anything more believable?
Mass settles out in the same way in an ordinary gravitational field as it does in a centrifuge - with the denser material at the bottom; it just takes longer in ordinary gravity. Newton’s laws still work; it’s just that less dense material experiences more fluid resistance (less density means more mass per unit surface area), so the less dense material falls more slowly, whether in ordinary gravity or in a centrifuge. At least that’s how I think it works - it’s just like dropping a handful of feathers and sand in an atmosphere; the sand will hit the ground first, separating from the feathers it was originally mixed with.
In Atmospheric Science, the Coriolis force is used to compensate for a rotating spherical reference frame. It’s a cool name for an interesting flow meter, but it could have a more accurate name.
Such as?