Determining method, system, reflector, vertical tank external measurement liquid level meter and mounting method thereof

A vertical tank external measurement liquid level meter, comprising an external measurement liquid level meter, an ultrasonic signal source locator, and a reflector;

• wherein the reflector is determined by performing operations comprising:
• determining a reference line segment;
• wherein an end point of the reference line segment is a position point T of an ultrasonic emission source, a length of the reference line segment is equal to a focal length P of the reflector;
• based on the focal length P and the position point T, constructing a first right-handed three-dimensional rectangular coordinate system O1X1Y1Z1, a second right-handed three-dimensional rectangular coordinate system TXPYPZP and a third right-handed three-dimensional rectangular coordinate system OXYZ;
• wherein the position point Tis at a positive value of an O1Y1 coordinate axis of the first right-handed three-dimensional rectangular coordinate system O1X1Y1Z1, and a length of a line segment O1T is equal to half of the focal length P;
• the position point T is a coordinate origin of the second right-handed three-dimensional rectangular coordinate system TXPYPZP, the second right-handed three-dimensional rectangular coordinate system TXPYPZP is obtained by translating the length of the line segment O1T in a direction of the positive value of the O1Y1 coordinate axis of the first right-handed three-dimensional rectangular coordinate system O1X1Y1Z1;
• a coordinate origin O of the third right-handed three-dimensional rectangular coordinate system OXYZ is at a positive value of the coordinate axis TXp of the second right-handed three-dimensional rectangular coordinate system TXPYPZP, and the coordinate origin O of the third right-handed three-dimensional rectangular coordinate system OXYZ is the other end point of the reference line segment;
• the length of the line segment TO is equal to the focal length P, the third right-handed three-dimensional rectangular coordinate system OXYZ is obtained by translating the length of the line segment TO in the direction of the positive value of the coordinate axis TXp of the second right-handed three-dimensional rectangular coordinate system TXPYPZP;
• and the position point T is located at a negative value of the OX axis of the third right-handed three-dimensional rectangular coordinate system OXYZ;
• according to the position point T and the focal length P, determining a basic cross section of the reflector on a O1X1Y1 coordinate plane of the first right-handed three-dimensional rectangular coordinate system O1X1Y1Z1;
• wherein the basic cross section is a basic parabola, the focal length of the basic parabola is the focal length P;
• the focus of the basic parabola is the position point T;
• and the basic parabola rotates with the O1Y1 coordinate axis as the rotation axis to form a paraboloid;
• determining a first cross section of the reflector on the TXpYp coordinate plane of the second right-handed three-dimensional rectangular coordinate system TXPYPZP according to the form of the parabolic equation in the second right-handed three-dimensional rectangular coordinate system TXPYPZP;
• wherein the first cross section is a first parabola;
• the focal length of the first parabola is the focal length P;
• and the focus of the first parabola is the position point T;
• determining a second cross section of the reflector on the TXpZp coordinate plane of the second right-handed three-dimensional rectangular coordinate system TXPYPZP according to the form of the parabolic equation in the second right-handed three-dimensional rectangular coordinate system TXPYPZP;
• wherein the second cross section is an arc;
• a radius of the arc is the focal length P;
• and a center of the arc is the position point T;
• determining a third cross section of the reflector on the OYZ coordinate plane of the third right-handed three-dimensional rectangular coordinate system OXYZ according to the form of the parabolic equation in the third right-handed three-dimensional rectangular coordinate system OXYZ;
• wherein the third cross section is a second parabola;
• the focal length of the second parabola is the focal length P;
• and the focus of the second parabola is the position point T;
• determining a parabolic reflector according to the basic cross section, the first cross section, the second cross section and the third cross section;
• wherein the center point of the parabolic reflector is the coordinate origin O;
• wherein the ultrasonic signal source locator comprises an ultrasonic transmitting probe, an ultrasonic transmitting circuit connected with the ultrasonic transmitting probe, an ultrasonic receiving probe, an ultrasonic receiving circuit connected with the ultrasonic receiving probe and an ultrasonic intensity indicator;
• wherein the ultrasonic transmitting probe emits ultrasonic waves to a vertical tank wall from the outside of a measured vertical tank, and the ultrasonic receiving probe receives ultrasonic signals from the inside of the vertical tank wall, uses the intensity indication displayed by the ultrasonic intensity indicator to find the position of the received strongest ultrasonic signals, and determines the position point T of the ultrasonic emission source formed on the inside of the vertical tank wall after the ultrasonic waves emitted by the ultrasonic transmitting probe from the outside of the vertical tank wall pass through the vertical tank wall;
• the reflector is configured to reflect an ultrasonic signal emitted by the ultrasonic emission source so that the reflected ultrasonic signal is emitted to a liquid level of the measured vertical tank along a preset direction, then reflected and returned back to the position point T of the ultrasonic emission source along the preset direction, and received by a measuring head of the external measurement liquid level meter, and wherein the focus of the reflector is the position point T, and the focal length of the reflector is the focal length P;
• and
• the external measurement liquid level meter is configured to measure a liquid level height in the measured vertical tank from the outside of the measured vertical tank based on the received ultrasonic signal from the measuring head and the emitted ultrasonic signal from the ultrasonic emission source.