JPH0634657Y2 - Device for measuring the amount of bubbles in liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an apparatus for measuring a residual gas in a liquid, that is, an amount of bubbles.

2. Description of the Related Art The amount of bubbles in a liquid is an important index for product quality in a raw material liquid such as a stock liquid. Conventionally, the amount of gas in the stock is shown by the ratio of the volume of the stock liquid and the volume of the gas contained therein under atmospheric pressure, and the main measurement methods are the gravimetric method, the partial pressure method, and the volume method. There are three types, and in particular, the volumetric method is extremely effective in that the result obtained by this is considered to have a high relevance to the amount of gas stored so as to directly affect the papermaking process.

Volumetric method is known as the so-called Boardway method,
This is to calculate the expansion amount of the retained gas when the stock liquid is depressurized to about 380 mmHg as a volume change and convert it to atmospheric pressure, but the operation procedure gives a burette scale. There are more than 10 steps including preparation and measurement of dyeing solution, preparation of sample solution, vacuum connection, reading of buret before connecting sample solution, connection of sample solution, and reading of buret after expansion and invasion of its gas holding. It requires operation, is complicated and time consuming, and is extremely difficult to combine with automatic measurement and automatic control.

This invention intends to provide an automatable device for measuring the amount of bubbles in liquid, which is based on the principle of the volumetric method and does not require a complicated operation such as the above-mentioned method of Boardway.

Means for Solving the Problems In order to achieve the above object, the bubble amount measuring device of the present invention comprises: a) a measurement side buffer tank and a reference side buffer tank having substantially the same volume; and b) intake air from both tanks. And a controllable exhaust / decompression line for achieving substantially the same decompression state, c) a differential pressure detector for detecting a difference in pressure between the two tanks, and d) a sample solution measuring volume. A sample liquid introduction and measurement line, comprising the sample liquid introduction and measurement line having a switching valve array for communicating one opening of the volume after measurement and sealing with the measurement side buffer tank after decompression. As a result, the pressure difference in the measurement side buffer tank according to the amount of bubbles in the measured sample liquid is detected by the differential pressure detector. It is intended.

Action According to the above configuration, one bubble amount measurement cycle is
There are only five stages: sample liquid introduction stage, buffer tank decompression stage, buffer tank closing stage, bubble extraction (measurement) stage from the measured sample liquid, and atmospheric pressure equilibration stage such as buffer tank and differential pressure detector. . This can be used for process control and automatic control by automatically repeating the process. In addition, the differential pressure before and after the introduction of bubbles corresponding to the amount of bubbles is not the difference between the two indication values of the pressure gauge, but the (differential pressure value itself) itself is directly connected by the indication value of zero to full scale. Accurate and highly sensitive measurement is possible.

Example FIG. 1 shows an example of the flow path configuration of a device for measuring the amount of bubbles in a liquid constructed according to the present invention. The sample solution introduction and measurement line (1) shown at the left end of the figure is a sample solution introduction port. (2),
It comprises a switching or opening / closing valve (3), a metering volume (4) consisting of a measuring tank or a coil, a second switching valve (5) and a sample liquid outlet (6) arranged in series.

The main function of the bubble measurement is the measurement side and reference side buffer tanks (7) and (8) and the differential pressure detector (9) that detects the pressure difference in these buffer tanks (7) and (8). Can be reached. That is, one end of each of the buffer tanks (7) and (8) is connected to the positive and negative inputs of the differential pressure detector (9), and the solenoid valves (1
0) and (11) and the dust filters (12) and (13) are connected to the outside air, respectively. In the embodiment, the measurement side buffer tank (7) is provided with a line (14), a switching or opening / closing valve (1) from a portion other than the one end.
5), the line (16), and the four-way joint (17) to connect to the decompression pump (18). The reference side buffer tank (8) is guided to the four-way joint (17) from the side opposite to the one end through the line (19), the switching or opening / closing valve (20) and the line (21). A pressure switch (22) is further connected to the four-way joint (17).

The above-mentioned measurement system and the above-mentioned sample liquid introduction line are connected by a line (23) passed between the switching valve (5) and the other end of the measurement side buffer tank (7).

In the above configuration, first, in the sample liquid introduction stage, the valves (3), (15) and (20) are set to the connection positions (the inlet / outlet ab connection positions), and the switching valve (5) is set to the sample liquid measurement position. By introducing (a-c connection position), the sample liquid is introduced into the measuring volume (4) from the sample liquid inlet (2),
Further, it is discharged from the sample liquid outlet (6) via the valve (5). At this time, both solenoid valves (10) and (11) are in the "closed" state. Next, as the depressurization stage of the buffer tanks (7), (8), etc., the pump (18) is operated and the inside of the measurement side buffer tank (7) and the reference side buffer tank (8) is set to 250 via each depressurization line. ~ 450
Reduce the pressure to mmHg. At this time, the pressure switch (22) detects the pressure in the decompression line and ensures the operation of the decompression pump (18) until the set pressure is reached. At the same time, the differential pressure detector is designed to indicate a zero pressure difference between the buffer tanks (7) and (8). Next, the buffer tank and the detector system are once closed, and valves (3), (15) and (2) are set in order to maintain a uniform depressurized state in the system.
0) is the shut-off position, and the switching valve (5) is also the neutral shut-off position. In this state, the buffer tanks (7), (8) are maintained at a constant pressure.

Here, by setting the switching valve (5) to the measurement position (ab connection position), the measurement side buffer tank (the measurement side buffer tank (a) in which the bubbles in the sample liquid measured in the measurement volume (4) are kept under reduced pressure ( 7), so that the pressure in the measurement side buffer tank (7) is increased according to the amount of bubbles in the sample liquid. The length and volume of the pipes are designed so that the pressure rise in the buffer tank (7) is proportional to the amount of bubbles in the sample liquid, and the differential pressure detector (9) has a reference side of constant pressure. Therefore, only this pressure change is detected as a differential pressure, which is supplied to the amplifier (24) via the pressure / current conversion element (9a) built in the detector (9) itself and recorded by the recorder (25). It is supposed to be done.

After measuring the amount of air bubbles, the two leak solenoid valves (10) and (11) are opened, and the flow paths of the buffer tanks (7) and (8) are exposed to the outside air through the dust filters (12) and (13), respectively. It is released to the state of atmospheric pressure equilibrium. With this, one measurement cycle is completed, and when the valves (3), (5) and (20) are set to the connection position again and the switching valve (5) is set to the sample solution introduction position (ac connection position), The sample liquid introduction and measurement in the measurement cycle will be started.

Preferably, the amount of bubbles in the sample liquid is continuously written to the recorder as the measurement cycle is repeated by automatically and continuously performing the above operation and appropriately performing the electrical processing of the detection signal. Be done.

FIG. 2 is a block diagram showing a concrete configuration example of a signal processing system including the differential pressure detector (9), the pressure-current conversion element (9a), the amplifier (24) and the recorder (25) shown in FIG. The detector (9 ') shown at the left end corresponds to the detector (9) and the pressure-current conversion element (9a) in FIG. 1, and the printer (25') is a recorder (25). Correspond. The amplifier (24 ') corresponding to the amplifier (24) in FIG. 1 is a preamplifier (26),
It consists of a main amplifier (27), a zero correction unit (28), a range switching and span correction unit (29), and the output of the main amplifier (27) is connected to a CPU (31) via an A / D converter (30). The CPU (31) drives not only the printer (25 ') but also the indicator light (32) and the air amount (air bubble amount) digital display device (33). Further, as various terminal outputs, analog transmission output, analog Output and setting output are
4), (35) and (36) respectively.

In addition, the circuit blocks in FIG. 2 will be easily understood from the names or abbreviations written in those blocks.

Effects of the Invention As described above, according to the device of the present invention, the amount of bubbles in the sample solution is accurately measured as the pressure difference between the two buffer tanks by repeating the relatively simple operation, and the measurement cycle is preferably performed. Can be effectively utilized for process control and automatic control.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow path configuration in an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration example of a signal processing system. (2) …… Sample liquid inlet (3), (15), (20) …… Switching or opening / closing valve (4) …… Measuring volume (5) …… Switching valve (6) …… Sample liquid outlet (7) …… Measuring side buffer tank (8) …… Reference side buffer tank (9) …… Differential pressure detector (10), (11) …… Solenoid valve (12), (13) …… Dust filter (17)… … Four-way joint (18) …… Decompression pump (22) …… Pressure switch

Claims (1)

[Scope of utility model registration request] 1. A) a measuring side buffer tank and a reference side buffer tank having substantially the same volume, and b) a controllable exhaust / depressurization line for sucking air from both tanks to bring them to substantially the same depressurized state. And c) a differential pressure detector for detecting a pressure difference between the two tanks, and d) a sample liquid introducing and measuring line having a sample liquid measuring volume, which is one of the volumes after measuring and sealing. By providing the sample solution introducing and measuring line having a switching valve array for communicating two openings with the measuring side buffer tank after decompression, the measuring side buffer according to the amount of bubbles in the measured sample solution An apparatus for measuring the amount of bubbles in a liquid, wherein an increase in pressure in a tank is detected by the differential pressure detector.