JPH0225157Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a viscometer, and particularly to a viscometer suitable for Pascal display.

[Conventional technology]

In recent years, the viscosity of liquids has been treated as an important control item for quality control of intermediate and final products and for understanding reaction conditions, and liquid viscosity meters have become effective sensors for monitoring and controlling processes.

Viscometers can be roughly divided into capillary viscometers, falling body viscometers, rotational viscometers, vibrational viscometers, and parallel plate viscometers based on their measurement principles.
Especially non-Newtonian liquids (gelatin, ink, etc.)
A rotational viscometer is used to measure the viscosity of.

Here, an overview of the rotary viscometer 2 in the prior art will be explained based on FIGS. 3 to 6.

In FIG. 3, 4 indicates a synchronous motor. A motor shaft 6 of this synchronous motor 4 is connected via a spiral spring 8 and a rotor shaft 10 to a rotor 12 immersed in the measuring liquid. On the motor shaft 6, there is a scale plate 14 on a disc with percentages displayed, and on the rotor shaft 10.
A pointer 16 is fixedly provided to each of the two, and the scale plate "0%" and the pointer are configured to coincide with each other in the initial state. On the other hand, on the lower end side of "0%" of the scale plate 14 and below the tip of the pointer 16,
Bar-shaped protrusions 18 and 20 are provided hanging down from each other (see FIG. 4), and the protrusions 18 and 20 extend between the light-emitting and light-receiving elements of the transmission type photointerrupters 22 and 24 provided below. is configured to pass through. The signal obtained by this transmission type photointerrupter is output to a phase detection circuit 26. The phase detection circuit 26 includes photointerrupters 22 and 24 as shown in FIG.
A flip-flop 28 that repeats setting and resetting upon receiving a signal from
and an AND circuit 32 which takes the logical product of the output of the oscillation circuit 30 and the output of the flip-flop 28;
It is composed of a counter 34 that counts the number of pulses output from the AND circuit 32 and a D/A converter 36 that converts the output of the counter 34 into analog. It is configured to output an electrical signal proportional to the percentage indicated on the scale plate. The phase information output from the phase detection circuit 26 is then output to a variable resistor 38, where it is divided into a predetermined value so that a predetermined display is made on a display unit 40. . The display unit 40 is composed of a double integral A/D converter, a digital voltmeter, etc., and the value displayed on the digital voltmeter is determined by the standard voltage for comparison V _REF and the measured voltage V _i . It's becoming like that. For example, if the display unit 40
When V _REF = 2.5V and _Vi = 2.5V, the phase detection circuit 26 detects the maximum deviation angle of 100 so that "199.9" is displayed.
Assuming that the variable resistor is configured to divide the output voltage of the D/A converter by 1/4 so that it outputs 5V when the angle is 0% and 0V when the minimum deviation angle is 0%,
When the declination angle of the viscometer reaches 100%, the output of the D/A converter 36 becomes 5V, and the measured voltage V _i becomes
Since it is 1.25V, the digital voltmeter 40 will display "99.9%", almost "100%".

In this conventional example, when the electric motor 4 rotates, this rotation is transmitted to the rotor 12 via the spring 8, and the viscous friction torque of the liquid acts on the outer circumference of the rotor 12 immersed in the measuring liquid. Steady rotation occurs when torque and spring force are balanced. At this time, since the magnitude of the torque is proportional to the value read from the declination angle of the pointer 16 fixed to the rotor shaft 10 with the scale plate 14 directly connected to the motor shaft 6, the viscosity (expressed in %) is Determined from the indicated value.

That is, during steady rotation, the "0%" on the scale plate coincides with the pointer in the initial state, but the whole rotates with a certain deviation angle. For this reason,
Among the signals detected by the photointerrupter, two signals having a phase difference proportional to the declination angle are obtained once per rotation of the electric motor 4. The flip-flop 28 is set by a signal detected by one photointerrupter 22, and reset by a signal detected by the other photointerrupter 24. Then, during the rise time of this flip-flop, the number of pulses output from the oscillator 30 is counted by the counter 34, and this is once converted into analog by the D/A converter 36 so that a predetermined display is made. The voltage is divided by a variable resistor 38, and the viscosity is displayed in % by a digital voltmeter 40.

[Problem that the invention attempts to solve]

However, when determining viscosity using a percentage display, the full scale is always 100% regardless of the motor rotation speed, rotor, etc., so the digital voltmeter 4
The variable resistor 38 is set so that a predetermined display is made at 0.
The output of the D/A converter 36 can be adjusted by using Pascal display. However, in Pascal display, the full scale changes depending on the rotation speed, rotor, etc. The variable resistor had to be adjusted to a predetermined voltage division ratio each time. Therefore, in the conventional technology, if the user wants to obtain Pascal display,
The Pascal display was determined by calculation from the percentage display determined by a viscometer by looking at catalogs, etc. For example, if the full scale determined by a certain rotor and rotation speed is 124 mPa.s, and the value determined by the viscometer is 50%, then the Pascal display is
The user calculated it to be 124mPa.s x 50%/100% = 62mPa.s.

That is, in the prior art, since there was no viscometer that displayed Pascal, there was a significant disadvantage that it was not possible to directly read the change in viscosity expressed in Pascal. On the other hand, in order to improve this inconvenience, it is possible to equip a CPU etc. to perform calculations.
The entire equipment becomes extremely expensive.

[Purpose of invention]

The present invention was devised in view of the disadvantages of the prior art, and aims to provide an inexpensive viscometer that can be directly read in both % and Pascal displays.
That purpose.

[Means for solving problems]

Therefore, in the present invention, the phase difference between the rotor that is introduced into the fluid to be measured, the motor that suspends this rotor via a spring and drives these rotors integrally, and the phase difference between this motor and the rotor is determined by electric power. A storage means storing full scale information determined from the rotation speed of the motor, the rotor, etc.;
A multiplication type D/A conversion circuit that multiplies the information outputted from the storage means as a coefficient and the signal outputted from the phase detection circuit as an input signal, thereby achieving the above object. This is what we are trying to achieve.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram of a scaling circuit 42 used in a viscometer according to an embodiment of the present invention.
This is the part corresponding to 8.

This scaling circuit 42 is connected to the phase detection circuit 2.
A multiplication type D/A that multiplies the analog voltage output from 6 by the digital input and outputs it as an analog current.
It is composed of a converter 44, an I/V conversion circuit 46 that converts a current signal into a voltage signal, and a ROM 48 that outputs digital information to the multiplication type D/A converter, and the information scaled by the scaling circuit 42. Next, a predetermined display is displayed on the display section 50.

The multiplication type D/A converter 44 is an element that multiplies the analog input voltage V _io and the digital input D _io and outputs the result in the form of an analog current, and usually converts the input digital signal D _io into the analog voltage V io. _io is used as a coefficient to convert it into an analog current _I0 , but in this embodiment, this is used in reverse, and the input analog voltage signal is converted to an analog current _I0 using a digital signal output from the ROM 48 as a coefficient. (See Figure 2).

On the other hand, the ROM 48 receives information such as the motor rotation speed, rotor, unit (p/%), etc. through a digital switch, and transfers the corresponding information to the multiplication type D/A converter 4 in accordance with the timing of the read signal.
4. It is designed to output to the display unit 50. The digital information output to the multiplication type D/A converter 44 becomes a coefficient for varying the input voltage V _io as described above, while the digital information output to the display section 50 changes the position of the decimal point on the display section. This information is used to change the displayed unit (% display, Pascal display).

In this way, the information scaled by the scaling circuit 46 is displayed on the display section 50 which is composed of a double integral D/A converter, a digital voltmeter, etc.
It is output to , and displayed in either % or Pascal.

Next, the configuration of the ROM 48 will be explained in more detail using a specific example.

Now, the double integral A/D installed in the display unit 50
When the standard voltage for comparison of the converter V _REF is 2.5V and the measurement voltage V ₀ is 2.5V, the digital voltmeter reads "199.9"
If the phase detection circuit 26 is configured to output 5V when the maximum declination is 100% and 0V when the minimum declination is 0%, when the % display is specified, the rotation speed, rotor, etc. Regardless, the information output from the ROM 48 may be information that attenuates the input voltage V _io by 1/4. In other words, when the declination angle of the viscometer is 100%, the input V _io of the D/A converter is 5 V and the measured voltage V ₀ is 5 × 1/4 = 1.25 V, so the digital voltmeter is “99.9 ” and a value close to 100% is displayed. On the other hand, when Pascal display is specified, if the full scale determined by the rotation speed and rotor etc. at that time is 124mPa.s,
The information output from ROM48 is input voltage V _io 3
The information may be attenuated by 1/100 (from 124/100×(1/4)). According to this, the declination angle of the viscometer is
When it is 100%, the output V _io of the phase detection circuit 26
is 5V, and the measured voltage V ₀ is 5 x 31/100 = 1.55, so with a digital voltmeter, it is (1.55/2.5).
×199.9≒124mPa・s is displayed. In other words, if information for attenuating the input voltage V _io is input in advance into the ROM 48 based on the above idea, it is possible to display percentages and pascals with a simple configuration of a multiplier D/A converter and ROM. Become.

The other configurations are completely the same as the conventional example described above.

Note that in the above embodiment, the scaling circuit 42
Although the other configurations have been described as being the same as those of the prior art, the present invention is not limited to this.
It can be used in all rotational viscometers that electrically output the phase difference between a motor that drives a rotor and the rotor.

[Effect of idea]

As described above, according to the present invention, there is provided a rotor that is introduced into a fluid to be measured, a motor that suspends this rotor via a spring and drives these rotors integrally, and a combination of this motor and the rotor. A viscometer equipped with a phase detection circuit that electrically outputs a phase difference, a storage means storing full scale information determined from the rotation speed of the motor, the rotor, etc., and information output from the storage means. Since we have adopted a configuration that includes a multiplication type D/A conversion circuit that uses the coefficient as a coefficient and multiplies the signal output from the phase detection circuit as an input signal, it is possible to obtain a viscometer that can be directly read in both % display and Pascal display at low cost. can be provided to

[Brief explanation of the drawing]

Fig. 1 is an electrical block diagram of a scaling circuit in a viscometer according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of a multiplication type D/A converter, and Fig. 3 is a schematic diagram of the main body of a viscometer according to the prior art. , FIG. 4 is a partially omitted side view of FIG. 3, FIG. 5 is an electrical block diagram of a prior art viscometer, and FIG. 6 is a timing chart of FIG. 4...Motor, 12...Rotor, 26...Phase detection circuit, 44...Multiplication type D/A conversion circuit, 48
...Memory means.

Claims (1)

[Claims for Utility Model Registration] A rotor inserted into a fluid to be measured, a motor that suspends this rotor via a spring and drives them to rotate integrally, and a phase difference between this motor and the rotor. In the viscometer, the viscometer is equipped with a phase detection circuit that electrically outputs a phase detection circuit, and a storage means that stores full scale information determined from the rotation speed of the motor, the rotor, etc., and a coefficient that stores the information output from the storage means. and a multiplication type D/A conversion circuit that performs multiplication by using the signal output from the phase detection as an input signal.