Temperature measuring apparatus

Claim 3

A method according to claim 1 wherein the pressure pulses are at each of a plurality of predetermined frequencies selected so that the signals are in phase during only one-half cycle.

Claim 4

A method according to claim 2 wherein the pulses are of equal duration and strung continuously together in time, and wherein the shifted amount for each pulse corresponds to N times its length where N equals the number of preceding wave trains in the pulse.

Claim 5

Apparatus for acoustically determining the temperature of a sound conducting fluid in the presence of ambient noise, comprising means for transmitting a plurality of pressure pulses through the fluid at each of a plurality of predetermined frequencies, means for reflecting each pulse at points a predetermined distance apart, means for detecting the reflections of each of said pulses together with the ambient noise and producing a plurality of electrical signals each representative of the reflections of a respective one of said pulses, means for filtering each of the electrical signals with a filter tuned to a respective one of said frequencies, means for recording each of the filtered electrical signals representative of respective pulses, means for shifting the time of the respective records by an amount which corresponds to the difference in time between the last half cycle in each pulse and a fixed time reference datum so that the peak amplitudes of the filtered electrical signals recorded, disregarding the presence of ambient noise, line up, means for reading out the shifted records simultaneously such that the signal read out includes two peaks representative of tHe time of the two reflections, and means for indicating the temperature in the fluid between the points of reflection in accordance with the interval between the two peaks.

Claim 6

Apparatus for acoustically determining the temperature of a sound conducting fluid in the presence of ambient noise, comprising means for transmitting a plurality of pressure pulses through the fluid at each of a plurality of predetermined frequencies, means for reflecting each pulse at points a predetermined distance apart, means for detecting the reflections of each of said pulses together with the ambient noise and producing a plurality of electrical signals each representative of the reflections of a respective one of said pulses, means for filtering each of the electrical signals with a filter tuned to a respective one of said frequencies, means for recording each of the filtered electrical signals representative of respective pulses, means for shifting the time of the respective records by an amount which corresponds to the difference in time between the last half cycle in each pulse and a fixed time reference datum so that the peak amplitudes of the filtered electrical signals recorded, disregarding the presence of ambient noise, line up, means for reading out the shifted records simultaneously such that the signal read out includes two peaks representative of tHe time of the two reflections, and means for indicating the temperature in the fluid between the points of reflection in accordance with the interval between the two peaks.

Claim 7

Apparatus according to claim 4 including means for adjusting the on-set times of each of the pulses in relation to the fixed time reference datum.

Claim 10

A method according to claim 6 wherein each of the received signals is recorded on a respective track on a multitrack recorder in two groups of tracks, and wherein the time range corresponds to the temperature range of interest, and wherein the read out recorded signals in each pair are from respective groups of tracks.

Claim 11

Apparatus for acoustically determining the temperature of a sound conducting fluid in the presence of ambient noise, comprising, means for transmitting a plurality of randomly spaced pressure pulses through the fluid, means for reflecting each pulse at points a predetermined distance apart, means for detecting the reflections of each of said pulses together with the ambient noise and for producing a plurality of electrical signals each representative of the reflections of a respective one of said pulses, multitrack recording means for recording each of the received signals in two groups of tracks, means for reading out each recorded signal after a number of different time delays spaced over a time range between pairs of tracks of different groups corresponding to the temperature range of interest, means for multiplying each of the read out signals on the tracks of one group with each of the read out signals on the tracks of the other group, and means for indicating the largest one of the multiplied products, thereby indicating the signal combination representing the temperature of the sound conducting fluid.

Claim 12

Apparatus for acoustically determining the temperature of a sound conducting fluid in the presence of ambient noise, comprising, means for transmitting a plurality of randomly spaced pressure pulses through the fluid, means for reflecting each pulse at points a predetermined distance apart, means for detecting the reflections of each of said pulses together with the ambient noise and for producing a plurality of electrical signals each representative of the reflections of a respective one of said pulses, multitrack recording means for recording each of the received signals in two groups of tracks, means for reading out each recorded signal after a number of different time delays spaced over a time range between pairs of tracks of different groups corresponding to the temperature range of interest, means for multiplying each of the read out signals on the tracks of one group with each of the read out signals on the tracks of the other group, and means for indicating the largest one of the multiplied products, thereby indicating the signal combination representing the temperature of the sound conducting fluid.