There are some pretty sloppy statements. I know that Damon is being
sarcastic, but that sarcasm is based on certain understandings. Let's
be more careful, everyone!
At 05:41 AM 7/21/2011, Damon Craig wrote:
The greatest souce of pressure is the water standing in the hose.
Probably not, but it's significant. First of all, what are the
starting conditions? Before the heating is started, the hose is full
of water, that water is flowing. From the Krivit video, perhaps from
others, the elevation of the hose above the floor can be estimated.
(For those who haven't looked, the hose is not in a "sink," it is in
a "sink drain," i.e, a hole in the wall where a sink might be installed.
If the hose end loops up 12 inches to dump into a bucket. There is
a head of water was the hose decends to the floor from the device
of 12 inches. The steam must push down upon this head to escape
raising the pressure in the device.
That is, to put it mildly, pucky. The elevation of the hose, to this
level, is irrelevant. The weight of the water in the hose will reduce
the pressure, were it not for the flow. Steam will *allow* increased
flow of the water. The pressure in the chamber will be *reduced* by
the water head from the difference in elevation between the chamber
and the water level in the bucket. With no boiling, there is a
contrary effect, increased pressure caused by the pump with its fixed
flow rate. That flow rate through the outlet orifice will increase
the pressure in the chamber. Only a little, I think.
See the Lewan video. In the sound track you can hear the steam
rising through the water column when the camera focuses on the hose exit.
It would be nice if someone would post the link, if they have it
handy when they are writing here!
There is an additional head from the submurged hose end in the
bucket. Add these to the submersion depth of the thermocouple and
there's plenty of added pressure to acount for 100.4 C, or whatever
it takes to cause general confusion.
Seems confusion can be caused with very little effort, or maybe even
no effort at all.
If it rises 30" to dump into a sink, think of all the free energy
that's gotta be there because the steam looks so much hotter. If the
exit is moved to the roof, you get even more free energy.
There isn't any sink. The hose in the Krivit demo goes down to the
floor, then rises to a sink drain. That's maybe 35 cm from the floor,
a very rough estimate. Since the sink drain is below the table where
the E-Cat is sitting, this will reduce the pressure in the E-Cat, not
increase it.
No, what increases the pressure in the E-Cat would be two sources:
pump pressure and steam pressure.
Stop the pump, and with no boiling, the pressure in an E-Cat with an
outlet hose full of water, leading down to a drain pipe, will be
below atmospheric pressure, by the relevant head. If you were to open
the steam escape valve at that point, air would flow in, not out.
On Tue, Jul 19, 2011 at 11:56 AM, Joshua Cude
<<mailto:[email protected]>[email protected]> wrote:
You're just guessing.
The pressure at 30 cm of water is enough to raise the bp by about a
degree. The chimney height can explain it.
Well, when I wasn't thinking carefully, I thought so. That would be
true if the top of the chimney were open to the air, and the chimney
was full of water. Which wouldn't stay that way, the water would flow
out the drain!
I'm amazed at how many stupid mistakes we can make. Babes in the woods.
No, increased pressure is caused by the pump (I have little idea how
much it will cause, but my guess is that this isn't enough to raise
the pressure to atmospheric), and by steam pressure from boiling.
Even a little boiled water will significantly raise the pressure.
This leads to a possible analysis. Has anyone done this? Basically,
it is possible to come up with a ball-park estimate of pressure from
the data on chamber temperature. The accuracy of the thermometer is
lousy, in fact, absent a pressure measurement. However, assuming
elevated temperature of one degree C., due to elevated pressure,
doing this in a preliminary way, inadequately checked, I came up with
a pressure of 1.04 bar. If that's overpressureof 40 millibars, that
would lead to a 40 lb/hr flow of steam through a half-inch orifice,
which is 5 g/sec., from an on-line calculator for steam flow through
an orifice.
that's remarkable, but is quite imprecise. This approach directly
calculates flow rate from some assumptions:
1. temperature of boiling water in the chamber of 100.6 degrees, vs.
in an open pot at 99.6 degrees, same probe but unknown specific care
in calibration.
2. Orifice of one-half inch. (It's probably less than that, the hose
is 15 mm ID? The orifice must be smaller, and walls are probably more
than 1.3 mm thick. Any figures from fittings?)
3. Head of water in hose was neglected. That head would increase flow
because the differential pressure between the inside and the outside
of the orifice would increase.
4. Pump-contributed pressure which would somewhat increase chimney
pressure was neglected.
