SU688865A1 - Vibration-type density meter - Google Patents

Description

The cutting device for pickup and excitation of vibrations 2 and 3 is connected to a vibrating sensitive element. A quartz thermosensitive resonator is installed in the body of the vibration sensing element 1 or in a controlled fluid and is included in the generator circuit 8, the output of which is connected to the input of the first mixer 5 through the first adjustable divider 9, the second input of which is connected to the reference quartz generator through the second controlled oscillator I. The output of the first mixer 5 is connected to the primary input of the second mixer 6, the other input of which is connected to the output of the amplifier 4, and the outputs of the controlled dividers 9 and 10 are connected to the inputs behind ominayuschego device 12, the outputs of which are connected to the inputs actuated divisors 9 and 10, the output of the second smeeitel 6 is connected to the input of the frequency converter - 13 nanr voltage.

Vibrating densitometer works as follows.

When a controlled fluid passes through a vibrating sensitive element 1 with the help of devices for picking up and exciting oscillations 2 and 3, amplifier 4 is excited at a frequency determined by the density of the fluid. The frequency signal from the output of amplifier 4 is fed to the input of mixer 6, to another input of which a signal is given whose frequency is equal to the frequency of the measuring signal at a density corresponding to the beginning of the measurement range of the vibration densitometer with a temperature coefficient of frequency equal to the temperature coefficient of the vibration sensitive element. To obtain this signal, a quartz thermosensitive resonator 7 is excited when it is included in the oscillator circuit 8. A frequency signal from the output of the oscillator 8 with a temperature coefficient of frequency, determined by the parameters of the thermosensitive resonator 7, is fed to the input of the controlled divider 9, where it is divided by the HI value (ni is equal to the ratio of the temperature coefficient of the thermosensitive resonator 7 and to the temperature coefficient of the frequency of the vibration sensitive element 1). Then, the frequency from the output of the quartz oscillator 11, previously divided in the second controlled divider 10 by the value of n, determined from the expression: is subtracted from the result obtained in the second mixer 6;

/one

N, 1

kl L .-- / o

where / 1 is the frequency of the reference crystal oscillator;

/ 2 - the frequency of the heat-sensitive generator;

/% / temperature coefficient of the frequency of the vibration sensitive element;

kt is the temperature coefficient of the frequency of the quartz resonator; / o is the frequency of the vibration sensitive element at a controlled density corresponding to the beginning of the socket.

The values of the coefficients p and p are stored in a memory device and are entered into dividers after each occurrence of pulses at their output.

Claims (1)

Invention Formula Vibration density meter consisting of a vibration sensitive element, a device for picking up and exciting oscillations, a reference crystal oscillator connected through a divider to a mixer connected to an amplifier and a signal converter, and a temperature sensor connected to a measuring circuit, characterized in that in order to increase the accuracy of measurement equipped with a generator, a second mixer and a divider, a temperature sensor made in the form of a quartz temperature-sensitive resonator is connected to the input of the generator, the output of which is through the first divide either connected to the first input of the first mixer, another the input of which through the second divider is connected to the reference quartz oscillator, the output of the first smael is connected to the first input of the second mixer, the other input of which is connected to the amplifier output, and the outputs of the divisors are connected to the inputs of the locking unit, the outputs of which are controlled E.my.my.