An orifice would help keep the flow tube full if the flow meter were mounted horizontally, but would create undesirable back pressure due to its flow resistance. The orifice could be just a gate valve that could be adjusted partly shut to provide flow resistance as needed to keep the pipe full at any given flow rate. However, how would you know that you created enough flow resistance to fill the pipe? It would be so much better to just make the flow meter mounted with a vertical flow axis (flowing up desirably).
I agree, a flow diagram of the system would be desirable to understand the potential errors. However, just a picture showing how the flow meter was mounted would suffice to know whether the half-full pipe was possible. If Rossi mounted the flow meter vertically, then half-full would not be possible. This type of flow meter would also not be usable for measuring steam flow and certainly not for mixed steam and water. While the gauge may be responsive to steam, its calibration would have to be completely different than for water, and its accuracy would be very sensitive to steam quality. On Mon, Aug 8, 2016 at 9:15 AM, Bob Cook <[email protected]> wrote: > Another question is whether there was a feed water pump that would > maintain a constant pressure on the flow meter and a full meter no matter > what the orientation. > > I would think such a system would require a constant flow and heat > transfer coeff. for the heat exchangers to maintain stability. > > There may also be an orifice to assure constant flow. > > A flow diagram of the system should be in hand before concluding issues > about flow. > > Bob Cook > ------------------------------ > *From:* Bob Higgins <[email protected]> > *Sent:* Monday, August 8, 2016 7:57 AM > *To:* [email protected] > *Subject:* Re: [Vo]:Problems with Rossi's flow meter described in court > document > > What I meant is that the flow axis (also the turbine propeller axis) > should be vertical to insure that the flow tube (housing the turbine) is > fully filled. > > I believe such turbines have a rotor (like a propeller) with an axis > coaxial with the flow tube and low blockage spider supports for the rotor > shaft. Then there is an electrical or mechanical coupling of the rotor > rotation to measure the flow speed usually out the side of the flow tube. > > If the flow tube were mounted horizontally and the pipe was half full, to > first order it would indicate twice the flow as actual. Second order > effects have to take into account the turning resistance of the turbine, > which is usually very low. Again, the turbine is measuring the speed of > the flowing medium whether it is full or not (to first order). > > On Mon, Aug 8, 2016 at 8:40 AM, Jed Rothwell <[email protected]> > wrote: > >> Bob Higgins <[email protected]> wrote: >> >> >>> Do you know the orientation of the flow meter? It is only possible to >>> have a pipe half full if the flow meter is mounted horizontally (a mistake >>> for use of this type of flow meter). >>> >> >> Umm . . . I don't follow what you mean. Do you mean the pipe should be >> vertical? I don't know what you mean by having the flow meter vertical. >> Like, sideways? It is a rotor smack in the middle of the pipe . . . so I >> don't get what you mean. >> >> The pipe was horizontal and the flow meter face plate is up. As far as I >> know. >> >> >> >>> If the flow meter was mounted horizontally, and the pipe was half full, >>> the turbine would turn at the speed of the water (same as if it were full) >>> - since a full pipe was presumed in the indication of rate, it would be in >>> error by the volumetric difference between the pipe full volume and the >>> pipe partly filled volume. >>> >> >> I believe the error can be complicated. It is not like: "the pipe is half >> full so the actual flow rate is half of what is indicated." A partially >> full pipe can produce a huge error. That is my impression reading about >> flow meters and using them myself, but I have no specific information on >> the extent of the error in Rossi's setup. (I think I.H. does have this >> information.) As you saw, I estimated it has to be at least 3. That seems >> plausible to me. >> >> - Jed >> >> >
