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| Which liquids can Magnum measure? | Magnum can measure any liquid with a minimum conductivity
of 1 micro Siemens/cm. This means virtually any water based liquid or chemical
including but not limited to:
Water
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| Which liquids can Magnum not measure? | Any liquid that acts as an electrical insulator,
such as:
Mineral Oils
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| Which pipe conditions are ideal for the installation of Magnum | As a single point measurement the Magnum insertion
sensor looks only at a small portion of the overall flow happening in a
given pipe. Under certain conditions this partial measurement will be representative
of the entire flow. Fortunately the laws of nature and physics tend to
favour the conditions under which Magnum can measure, and so in most filled
pipes at most times this means fully developed turbulent flow with a symmetrical
flow profile. Fully developed turbulent flow requires a sufficient amount
of straight pipe run and a sufficient liquid velocity. The general rule
of thumb is to locate a flowmeter installation 10 pipe diameters downstream
and 5 pipe diameters upstream of an obstruction, such as a valve or an
elbow. Often this this may be far more then required, since the key is,
how long it takes the liquid after an obstruction to once again acquire
its symmetrical flow profile.
There is a common misconception that turbulence is a bad thing. In fact turbulence is the deciding beneficial factor here; because it is turbulence, based on velocity and pipe size, which will overcome the effects of the flow obstruction and return the flow to its symmetrical pattern. The more turbulent and fast the flow the better! Consequently in larger pipes with faster flow up and downstream distances can be significantly reduced without adversely affecting the performance of the flowmeter. The opposite of turbulent flow, laminar flow, is indeed far more difficult to measure because it may be that portions of the water column are moving while others are not - creating very asymmetrical flow. The turbulence of a liquid is often expressed with the Reynolds number (This is not a defined unit, but rather an expression of a relationship). The switch between turbulent and laminar occurs somewhere around Re.No 2300. Most flow in most pipes far exceeds this number making the single point measurement of the Magnum flowmeter a very viable alternative to traditional measurement methods. |
| Which pipe conditions adversely affect the performance of Magnum | Air accumulation: The pipe in which magnum
is measuring must be completely filled with liquid. There is a variety
of conditions under which this may not be the case. Differences in water
pressure can contribute to the formation of bubbles when gasses no longer
remain in solution. In longer pipe systems this may cause the formation
of gas pockets in sections with higher elevation. depending on the pipe
configuration these pockets can persist even against relatively fast flowing
liquid. If the sensor is placed in such a location three things can happen:
a) the electrodes are exposed to air and the flowmeter cannot measure,
b) Since the flow equation assumes that the entire area of the pipe is
filled with liquid the calculation made by the flowmeter will be in error,
i.e. the flowmeter will read too high, c) whenever the air pocket is dragged
past the electrodes by increased liquid velocity the flowmeter will register
a spike or erroneous reading of some form.
Vortices: Sometimes when water is pumped from a reservoir with an exposed surface a vortex may form. This kind of vortex can pull air into the pipe for some considerable distance and this may interfere with the measurement. Interference: Branch lines or chemical injections should be as far removed from the measurement point as possible, as the will interfere with the flow profile in the entire pipe for some distance. |
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