Measurement of process product dielectric constant using a low power radar level transmitter
AssigneeRosemount Inc.
InventorKurt C. Diede
Life of this patent
Estimating the term…
Abstract
Disclosed is a method of using a low power radar level transmitter to calculate a dielectric constant of a product in a tank. Low Power Time Domain Reflectometry Radar (LPTDRR) circuitry is controlled to calculate a time delay between transmission of microwave energy down a termination extending into the product in the tank and reflection of the microwave energy. In some embodiments, the dielectric constant of the product is calculated as a function of the time delay. In other embodiments, the dielectric constant is calculated by controlling the LPTDRR circuitry to calculate amplitudes of transmit and receive pulses. The dielectric of the product is calculated as a function of the amplitudes of the transmit and receive pulses.
Claims14
A low power radar level transmitter for measuring a dielectric constant of a process product having first and second product interfaces, the transmitter comprising:
- a termination extendable into the process product;
- a pulse generator coupled to the termination, the pulse generator adapted to generate a microwave transmit pulse which is transmitted along the termination into the product, a first portion of the transmit pulse being reflected at a first product interface and a second portion of the transmit pulse being reflected at a second product interface;
- a pulse receiver coupled to the termination and adapted to receive a first reflected wave pulse corresponding to reflection of the first portion of the transmit pulse at the first product interface, and receiving a second reflected wave pulse corresponding to reflection of the second portion of the transmit pulse at the second product interface;
- a threshold controller coupled to the pulse receiver and adapted to detect whether the first reflected wave pulse at least meets a first threshold value and to provide receive pulse output information based upon detection of the first reflected wave pulse;
- a dielectric constant calculator coupled to the threshold controller;
- and
- wherein the threshold controller is further adapted to detect whether the second reflected wave pulse at least meets a second threshold value, the threshold controller providing the receive pulse output information based upon detection of the first and second reflected wave pulses.
A low power radar level transmitter adapted to measure a dielectric constant of a process product having first and second product interfaces, the transmitter comprising:
- low power time domain reflectometry radar (LPTDRR) circuitry;
- means for controlling the LPTDRR circuitry to calculate a time of travel of microwaves through a known distance of the product which is proportional to the dielectric constant of the product;
- and
- means for calculating the dielectric constant of the product as a function of the time of travel.
A method of using a low power radar level transmitter to measure a dielectric constant of a process product having first and second product interfaces, the method comprising:
- controlling low power time domain reflectometry radar (LPTDRR) circuitry in the transmitter to direct microwave energy into the process product;
- controlling LPTDRR circuitry to receive reflected microwave energy from the process product;
- controlling LPTDRR circuitry to calculate a parameter based upon reception of the microwave energy which parameter is proportional to the dielectric constant of the product;
- calculating the dielectric constant of the product as a function of the calculated parameter;
- and
- wherein the parameter is a time delay between transmission of microwave energy down a termination extending into the product and reflection of the microwave energy.
Dependencies are inferred from the claim text.