SU735940A1 - Microbarograph - Google Patents

Description

(54) MICROBAROGRAPH

The invention relates to geophysical instrumentation and is intended to record changes in atmospheric pressure in order to predict earthquakes, detect artificial atmospheric disturbances, and study the effect of changes in atmospheric pressure on the readings of geophysical instruments and the ground surface.

A microbarograph is known, containing two blocks of aneroid boxes, between which a mirror and a photo-recording device 1 are fastened on a twisted spring.

At the same time, the photoregistration device is made two-channel, and the optical system of one of the channels is equipped with an additional mirror for obtaining mirror-symmetric curves.

Also known is a photoelectric microbarograph containing blocks of aneroid boxes, a multiplying-transmission mechanism in the form of a double cylindrical spring, a system for measuring and recording pressure, which is equipped with a power compensator made in the form of a frame of a magnetoelectric inverse transducer fixed in the middle part of a double 1 1

shtkt

cylindrical spring and acting on the blocks of the aneroid boxes 2. The disadvantages of the known microbarographs are the large zero point drift and the significant temperature coefficient 5 of the sensitive system.

The closest technical solution to the present invention is a microbarograph, comprising a housing, a barometric sensor, a photoelectric converter,

10 reading device and recorder 3. Moreover, a barometric sensor consisting of a frame, suspension strands, a mirror, a rocker arm and a hollow hermetic ball rigidly fixed on one of the ends

J5 of the yoke, a spring is inserted, the elastic moment of which is compensated by the elastic moment of the twisted threads of the sensor hanger, connected at one end through the lever with the sensor mirror, and at the other end rigidly fastened to the body, and the counterweight, located at the second end of the sensor rocker arm and consisting of a threaded bushings with three nuts shifting along it. However, this microbarograph also records long-period changes in atmospheric pressure. This limits the increase in its sensitivity.

The aim of the invention is to increase the sensitivity of the microbarograph to short-period changes in atmospheric pressure and to eliminate the long-period background of changes in atmospheric pressure.

The goal is achieved by inserting a vertically mounted capillary into the barometric sensor of the device, the lower end of which communicates with the cavity of the ball, and the upper end with the controlled medium.

In addition, in order to simplify the design of the device, the counterweight of the barometric sensor is made in the form of a slider of the photoelectric converter, and the measuring spring is equipped with a micrometer screw.

On. The drawing shows the microbarograph design.

On the base (not shown in the drawing) of frame 1 on yarn x 2 and 3, the yoke 4 of the barometric sensor is suspended, on one end of which a hollow ball 5 with capillary 6 is rigidly fixed, and on the other counterweight 7, made in the form of a rectangular vertical located metal shutter with a rectangular neckline 8 at the level of the rocker arm. On one side of the shutter, at the level of the cutout, the infrared light-emitting diode 9 is located, on the other hand, the differential photocell 10. Moreover, the shoulders of the photocell, in the absence of changes in the pressure of the controlled medium, are arranged symmetrically with respect to the cutout 8. The photocell is connected to the PCB recorder 11. The offset of the rocker arm 4 is made using a measuring spring 12, one end of which is connected to the rocker arm and the other with a micrometer screw 13. To eliminate the zero point drift of the barometric sensor and the temperature effects on it, the elastic moment of the measuring spring for the initial position is fully compensated by an elastic the moment of the twisted threads 2 and 3 suspensions. To prevent breakage of the barometric sensor during transportation, a limiter 14 of the rocker arm 4 is provided.

Microbarograph works as follows.

The power supply to the LED circuit 9 is supplied. The light flux of the LED through the rectangular notch 8 of the shutter 7 illuminates the middle part of the photocell 10. If both arms of the photocell are lit equally, the current in the photocell circuit connected to the recorder 11 will be zero. The barometric sensor oscillates due to changes in atmospheric pressure. In this case, the infrared radiation of the LED is shifted along the photocell, and a current arises in the circuit of the photocell. The logger records the change in atmospheric pressure. Since the hollow key of the sensor communicates with the environment using a capillary, the long-period changes in atmospheric pressure do not affect the sensor — the pressure inside and outside the ball will be the same after some time. For short periods of time, the pressure inside and outside the shara does not have time to level. Therefore, the rocker arm of the sensor oscillates, the sign of which is determined by the sign of the change in pressure in the environment.

When atmospheric pressure decreases under the action of Archimedes force, the sensor rocker deflects downwards. This deviation also contributes to the excess air pressure inside the hollow ball. The air from the balloon through the capillary enters the environment until the pressure inside and outside the balloon becomes the same. The exit of air from the ball deflects the rocker also downwards and thereby increases the sensitivity of the barometric sensor to short-period changes in atmospheric pressure. With an increase in atmospheric pressure, the pattern of behavior of the barometric sensor changes to the opposite. The frequency band of atmospheric pressure oscillations recorded by the microbarograph depends on the diameter of the capillary — the larger the diameter of the capillary, the smaller the frequency band, the higher frequencies the microbarograph detects.

Adjusting the initial position of the photovoltaic converter slider is carried out by changing the tension of the measuring spring 12 using a micrometer screw 13.

The invention provides an increase in the sensitivity of the microbarograph 5-8 times compared with the prototype.

Nullpoint drift and change in microbarograph metrological characteristics

0 under the action. temperature changes below the threshold of its sensitivity.

Claims (3)

Invention Formula A microbarograph containing a base, a barometric sensor in the form of a hollow ball with a rocker on which a counterweight and a movable end of the measuring spring are fixed, a photoelectric transducer, a counting device and a recorder, characterized in that, in order to increase its sensitivity and simplify the design, The counterweight of the barometric sensor is designed as a shutter of the photoelectric converter, the measuring spring is equipped with a micrometer screw, and the barometric sensor is inserted vertically The flared cap p, the lower end of which communicates with the cavity of the ball, and the upper end with the controlled medium. Sources, information taken into account during the examination 1. USSR author's certificate No. 215571; cl. G 01 L 7/00, 1967. 2. USSR author's certificate number 257811, cl. G 01 L 9/00, 1068. 3. USSR author's certificate No. 569885, cl. G 01 L7 / 12, 1976 (prototype)