Method and apparatus for determining wet bulb globe temperature

Claim 3

Apparatus for determining the wet bulb globe temperature of surroundings including: a. a wet bulb thermometer for locating in said surroundings and incorporating a first temperature sensor to provide a first signal representative of the wet bulb temperature of said surroundings, b. a globe thermometer having a globe of a predetermined diameter for locating in said surroundings and incorporating a second temperature sensor to provide a second signal repreSentative of the measured globe thermometer temperature of the surroundings, said predetermined diameter being such that the measured globe thermometer temperature closely approximates the sun of two-thirds the standard 6 inch globe temperature of said surroundings plus one-third the dry bulb temperature of said surroundings, c. first weighting means for applying a weighting factor of 0.3 to said second signal to provide a third signal, d. second weighting means for applying a weighting factor of 0.7 to said first signal to provide a fourth signal, e. summation means for electronically summating said third and fourth signals to provide a weighted summation signal, f. comparing means for obtaining the difference between said weighted summation signal and a reference signal to provide a fifth signal corresponding to the wet bulb globe temperature of said surroundings, and g. indicator means for receiving said fifth signal and responding thereto to provide an indication corresponding to the wet bulb globe temperature of said surroundings.

Claim 4

Apparatus for determining the wet bulb globe temperature of surroundings including: a. a wet bulb thermometer for locating in said surroundings and incorporating a first temperature sensor to provide a first signal representative of the wet bulb temperature of said surroundings, b. a globe thermometer having a globe of a predetermined diameter for locating in said surroundings and incorporating a second temperature sensor to provide a second signal repreSentative of the measured globe thermometer temperature of the surroundings, said predetermined diameter being such that the measured globe thermometer temperature closely approximates the sun of two-thirds the standard 6 inch globe temperature of said surroundings plus one-third the dry bulb temperature of said surroundings, c. first weighting means for applying a weighting factor of 0.3 to said second signal to provide a third signal, d. second weighting means for applying a weighting factor of 0.7 to said first signal to provide a fourth signal, e. summation means for electronically summating said third and fourth signals to provide a weighted summation signal, f. comparing means for obtaining the difference between said weighted summation signal and a reference signal to provide a fifth signal corresponding to the wet bulb globe temperature of said surroundings, and g. indicator means for receiving said fifth signal and responding thereto to provide an indication corresponding to the wet bulb globe temperature of said surroundings.

Claim 5

Apparatus according to claim 2 wherein the predetermined diameter of the globe of said globe thermometer lies in the range 1.45 to 1.85 inches.

Claim 6

Apparatus according to claim 3 wherein the predetermined diameter of the globe of said globe thermometer is 1.65 inches.

Claim 7

Apparatus according to claim 2 wherein said second temperature sensor is a silicon diode temperature sensor within said globe.

Claim 8

Apparatus according to claim 3 wherein said second temperature sensor is a silicon diode temperature sensor within said globe.

Claim 9

Apparatus according to claim 2 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, and b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor.

Claim 10

Apparatus according to claim 3 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, and b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor.

Claim 11

Apparatus according to claim 5 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, and b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor.

Claim 12

Apparatus according to claim 2 wherein: a. said first and temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, and d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential.

Claim 13

Apparatus according to claim 3 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, and d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential.

Claim 14

Apparatus according to claim 5 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connection to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, and d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential.

Claim 15

Apparatus according to claim 2 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential, and e. a negative feedback connection from the output of said operational amplifier to said negative inverting input of said operational amplifier.

Claim 16

Apparatus according to claim 3 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a comMon junction, d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential, and e. a negative feedback connection from the output of said operational amplifier to said negative inverting input of said operational amplifier.

Claim 17

Apparatus according to claim 5 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential, and e. a negative feedback connection from the output of said operational amplifier to said negative inverting input of said operational amplifier.

Claim 18

Apparatus according to claim 2 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential, and e. said regulated source of potential includes a further operational amplifier with its negative input terminal connected to the junction of fifth and sixth resistors connected in series across said output leads of said regulated source of potential, the output of said further operational amplifier being connected to the positive one of said output leads of said regulated source of potential, and its positive non-inverting input being connected to the source electrode of a field-effect transistor which is also connected to the negative one of said output leads through seventh and eighth resistors in series, the gate electrode of said field-effect transistor being connected to the junction of said seventh and eighth resistors, and the drain electrode of said field-effect transistor being connected to said positive one of said output leads.

Claim 19

Apparatus according to claim 3 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connecTed together in a common junction, d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential, and e. said regulated source of potential includes a further operational amplifier with its negative input terminal connected to the junction of fifth and sixth resistors connected in series across said output leads of said regulated source of potential, the output of said further operational amplifier being connected to the positive one of said output leads of said regulated source of potential, and its positive non-inverting input being connected to the source electrode of a field-effect transistor which is also connected to the negative one of said output leads through seventh and eighth resistors in series, the gate electrode of said field-effect transistor being connected to the junction of said seventh and eighth resistors, and the drain electrode of said field-effect transistor being connected to said positive one of said output leads.

Claim 20

Apparatus according to claim 5 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential, and e. said regulated source of potential includes a further operational amplifier with its negative input terminal connected to the junction of fifth and sixth resistors connected in series across said output leads of said regulated source of potential, the output of said further operational amplifier being connected to the positive one of said output leads of said regulated source of potential, and its positive non-inverting input being connected to the source electrode of a field-effect transistor which is also connected to the negative one of said output leads through seventh and eighth resistors in series, the gate electrode of said field-effect transistor being connected to the junction of said seventh and eighth resistors, and the drain electrode of said field-effect transistor being connected to said positive one of said output leads.

Claim 21

Apparatus according to claim 2 wherein: a. said first and second temperature sensors are silicon diode temperature sensors connected respectively in series with first and second resistors across output leads of a regulated source of potential, b. said first weighting means includes a third resistor having one end connected to the junction of said first temperature sensor and said first resistor, and said second weighting means includes a fourth resistor having one end connected to the junction of said second temperature sensor and said second resistor, c. the other ends of said third and fourth resistors being connected together in a common junction, d. said comparing means is an operational amplifier having its positive non-inverting input connected to said common junction and its negative inverting input connected to said reference signal, said reference signal being a voltage derived from said regulated source of potential, and e. a meter overload protection means connected between said opErational amplifier and said indicator means, said meter overload protection means comprising two diodes oppositely-connected face-to-face in the lead from the output of said further operational amplifier to the input of said indicator means, and a field-effect transistor connected between the junction of said two diodes and a negative potential with its drain electrode connected to said junction between the two diodes.

Claim 22

Apparatus according to claim 2 wherein said indicator means includes an indicating pointer movable over a scale calibrated in wet bulb globe temperature degrees and wherein said apparatus is constructed as a portable instrument.