LEVEL MEASUREMENT INSTRUMENT
A level measurement instrument including: a transmitter configured to transmit an electromagnetic transmission signal, the electromagnetic transmission signal being a microwave signal or a radio wave signal a receiver configured to receive a plurality of electromagnetic return signals; an elongate electromagnetic radiation guide coupled to the transmitter to guide the electromagnetic transmission signal, wherein the elongate electromagnetic radiation guide is provided with a plurality of windows spaced along the elongate electromagnetic radiation guide, the windows being at least partially transmissive to the electromagnetic transmission signal such that in use, when the elongate electromagnetic radiation guide is introduced into a fluid column, the electromagnetic transmission signal interacts with fluid adjacent each window and generates electromagnetic return signals, the return signal from each window being dependent on a parameter of the fluid adjacent each window such that different fluids in the fluid column have different return signals.
1 - 12 . (canceled)
13 . A level measurement instrument comprising:
a transmitter configured to transmit an electromagnetic transmission signal, the electromagnetic transmission signal being a microwave signal or a radio wave signal;
a receiver configured to receive a plurality of electromagnetic return signals;
an elongate electromagnetic radiation guide coupled to the transmitter to guide the electromagnetic transmission signal;
wherein the elongate electromagnetic radiation guide is provided with a plurality of windows spaced along the elongate electromagnetic radiation guide, the windows being at least partially transmissive to the electromagnetic transmission signal such that in use, when the elongate electromagnetic radiation guide is introduced into a fluid column, the electromagnetic transmission signal interacts with fluid adjacent each window and generates electromagnetic return signals, the return signal from each window being dependent on a parameter of the fluid adjacent each window such that different fluids in the fluid column have different return signals, and
wherein the receiver is configured to differentiate between the electromagnetic return signals and thus determine a level of one or more fluids in the fluid column based on a difference in relative permittivity of different fluids in the fluid column.
14 . The level measurement instrument according to claim 13 ,
wherein the elongate electromagnetic radiation guide is configured such that fluid does not enter the elongate electromagnetic radiation guide through the windows when the elongate electromagnetic radiation guide is introduced into a fluid column.
15 . The level measurement instrument according to claim 14 ,
wherein the elongate electromagnetic radiation guide is formed of a tubular member through which the electromagnetic transmission signal is guided in use, and
the windows are sealed by a solid transmission material which is at least partially transparent to the electromagnetic transmission signal.
16 . The level measurement instrument according to claim 15 ,
wherein the solid transmission material at least partially fills an interior of the elongate electromagnetic radiation guide.
17 . The level measurement instrument according to claim 15 ,
wherein the tubular member is metallic and the solid transmission material is a glass or a ceramic.
18 . The level measurement instrument according to claim 13 ,
wherein the windows are formed by slots in the elongate electromagnetic radiation guide thus providing a slotted wave guide.
19 . The level measurement instrument according to claim 13 ,
wherein the transmitter is configured to transmit electromagnetic radiation having a frequency in a range 0.3 GHz to 300 GHz.
20 . The level measurement instrument according to claim 19 ,
wherein the transmitter is configured to transmit electromagnetic radiation having a frequency in a range 2 GHz to 20 GHz.
21 . The level measurement instrument according to claim 13 ,
wherein the transmitter and the receiver are disposed in a housing at one end of the elongate electromagnetic radiation guide.
22 . The level measurement instrument according to claim 13 ,
wherein the receiver is disposed in a separate housing spaced apart from the elongate electromagnetic radiation guide.
23 . A method of measuring a level of one or more fluids in a fluid column, the method comprising:
introducing the level measurement apparatus according to claim 13 into the fluid column such that the elongate electromagnetic radiation guide extends through the fluid column;
transmitting an electromagnetic transmission signal, the electromagnetic transmission signal being a microwave signal or a radio wave signal, through the elongate electromagnetic radiation guide such that the electromagnetic transmission signal interacts with fluid adjacent each window and generates electromagnetic return signals, the electromagnetic return signal from each window being dependent on a parameter of the fluid adjacent each window such that different fluids in the fluid column have different return signals;
receiving the electromagnetic return signals; and
processing the return signals to differentiate between the electromagnetic return signals from each of the windows and determine a level of one or more fluids in the fluid column based on a difference in relative permittivity of different fluids in the fluid column.
24 . A system comprising a vessel for housing a fluid, and a level measurement instrument according to claim 13 , the level measurement instrument being mounted such that the elongate electromagnetic radiation guide of the level measurement instrument extends through the vessel.