JPH0452675Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to an apparatus for measuring the amount of bubbles in a liquid, for example, for sampling a liquid to be measured such as sludge whose concentration is to be detected and measuring the amount of bubbles in the liquid.

[Conventional technology]

Generally, a liquid such as sludge contains air bubbles, and these air bubbles cause an error in the measured concentration of the liquid, so it is necessary to measure the amount of air bubbles for accurate concentration planning. Conventional measuring means of this type include, for example, the method of calculating the concentration of a liquid from changes in the volume and weight of the liquid in response to changes in temperature and pressure, as shown in US Pat. No. 3,229,503, and the method disclosed in US Pat. No.
No. 3680962 describes a method of measuring the amount of light transmitted through a liquid before and after pressurization, thereby calculating the amount of solids and bubbles contained in the liquid, and There was a device that measured the carbon dioxide content based on the deviation from a standard value, as disclosed in Japanese Patent No. 1983-30397.

[Problem that the invention attempts to solve]

In any case, such conventional measuring means have the problems of being large-scale measuring instruments and their ancillary equipment, and having complicated configurations, which inevitably increases costs and lacks versatility. The problem was that it was not possible to obtain accurate measurement accuracy. This invention was made in order to solve the above-mentioned problems, and the object is to obtain an apparatus for measuring the amount of bubbles in a liquid that can easily and accurately measure the amount of bubbles in a liquid to be measured.

[Means for Solving the Problems] The device for measuring the amount of bubbles in a liquid of this invention includes a lid that seals the upper end opening of a container containing a liquid to be measured, and a lid that penetrates the lid and enters the container. A diaphragm is attached to the inserted tip, a measuring tube is provided with a liquid stored inside and pressurized air is introduced from an external air supply system, and a pressure sensor that detects the liquid pressure in the container. be.

[Effect]

In this device, a sample of the liquid to be measured is placed in a container to substantially fill the container, and the top opening of the container is sealed with a lid, so that the container is filled with liquid so that no gas remains at the top. . In this state, when pressurized air is supplied into the measurement tube from the external air supply system, the diaphragm at the tip of the measurement tube expands like a balloon under the pressure of the pressurized air, indirectly causing the liquid to be measured in the container to is pressurized. At this time, the pressure inside the pressurized container is detected by a pressure sensor, and after a period of time has elapsed from the time when the detected pressure reaches a predetermined pressure until the liquid to be measured in the container reaches an equilibrium state, the liquid in the measuring tube is Measure the amount of decrease in position. The amount of bubbles in the liquid can be easily calculated from the measured value.

【Example】

An embodiment of this invention will be described below based on the drawings. In FIG. 1, reference numeral 1 denotes a container for receiving a liquid to be measured, which has a bottomed cylindrical shape with an open upper end, and a lid 2 is provided at the upper end opening. In this embodiment, the lid 2 is removably fastened to the upper opening of the container 1 with a screw 4 via an annular packing 3. A bulging portion 5 is provided on the inner surface of the lid 2 to expose the upper part of the interior of the container 1 when the upper end opening is sealed. This bulging portion 5 is formed into a spherical shape in the illustrated example. The container 1 is inserted through the center of the lid 2.
A measuring tube 6 opening inward is provided. The measuring tube 6 contains a liquid, is connected above to an external air supply system (not shown) such as a compressor, and has a diaphragm 7 at its lower end that separates it from the liquid to be measured in the container. On the other hand, the container 1 is provided with a pressure sensor 8 for detecting the liquid pressure within the container. Next, the operation of the above embodiment will be explained. first,
The lid 2 is removed and the liquid to be measured, such as sludge, is introduced into the container 1 to a substantially full state. After the introduction, the upper end opening of the container 1 is sealed with the lid 2. When the lid 2 is closed, the bulging portion 5 of the lid presses the liquid to be measured, so that a portion of the liquid to be measured overflows to the outside from the upper opening of the container 1. As a result, the inside of the container 1 is filled with the liquid to be measured. In this state, when pressurized air is supplied to the measurement tube 6 from the external air supply system, the pressurized air passes through the liquid held in the measurement tube 6 to the diaphragm 7.
is inflated like a balloon to pressurize the liquid to be measured in the container 1. At this time, the pressure of the liquid to be measured in the container 1 is detected by the pressure sensor 8. When the pressure value of the liquid to be measured by the pressure sensor 8 reaches a predetermined pressure (for example, 2 to 10 kg/ ^cm2 ), from that point until the liquid to be measured in the container 1 reaches an equilibrium state, After a period of time has elapsed, the amount of decrease in the water level of the liquid in the measuring tube 6 is measured visually, by reading the water level using a microscope, or indirectly by measuring capacitance, electric resistance, magnetic field, or the like. By dividing this liquid level decrease amount by the capacity of the container 1, the amount of bubbles in the liquid to be measured can be accurately calculated. That is, according to Boyle's law, by pressurizing the liquid to be measured and measuring the volume of the reduced bubbles, the amount of bubbles in the liquid to be measured can be calculated accurately. Next, we will explain using actual measurement data. Container 1 shown in Figure 1 (inner diameter 80mmφ, height 120mm,
An effective capacity of 573 cm ³ ) was filled with anaerobic digested sludge from a municipal sewage treatment facility adjusted to 20°C to prevent air from entering, and the container was sealed. Pour an appropriate amount of colored water into the measuring tube 6 with a glass scale,
When nitrogen gas is gradually introduced from the upper tip, the water level at the time when the pressure sensor 8 stably indicates a gauge pressure of 5 kg/cm ² after 5 minutes has passed is lower than the original water level.
It had decreased by 13.3m1. Separately, we measured the amount of decrease in water level when the pressure was changed step by step, and the results were as shown in Figures 3 and 4. The original bubble volume V [m1] is the bubble volume after pressurization.
It is equal to V′ [m1] plus the reduced water level amount 13.3 [m1]. V=V'+13.3 ... Also, from Boyle's law, PV=P'V' Here, P or P' is absolute pressure (Kg/cm ² ), and absolute pressure = gauge pressure + atmospheric pressure Therefore, the unit of atmospheric pressure expressed in Kg/cm ² is 1.0332. Therefore, by substituting V'=PV/P'=1.0332×V/(5+1.0332)..., V can be found. V = (5 + 1.0332) / 5 × 13.3 = 16 m1 Similarly, when a known amount of air is added to pure water with a syringe and pressurized, the amount of bubbles can be determined from the amount of decrease in the water level in the measuring tube 6. This was confirmed. Further, as shown in FIG. 2, inlet and outlet pipes for introducing and discharging the liquid to be measured may be provided in the container 1, and the introduction and discharging may be performed automatically.

[Effect of the idea]

As described above, according to this invention, by simply sampling the liquid to be measured such as sludge, placing it in a container, sealing the container, and introducing pressurized air into the measuring pipe connected to the container, The amount of decrease in the liquid level in the measuring tube after the time has elapsed from the time when the pressure detection value of the measured liquid in the container reaches a predetermined pressure by the pressure sensor installed in the measuring tube until the measured liquid reaches an equilibrium state. By measuring, it is possible to accurately calculate the amount of bubbles contained in the liquid to be measured. Therefore, when measuring the concentration of a liquid such as sludge, it is possible to prevent measurement errors due to the size of the bubble content contained in the liquid, and it is possible to obtain an effect that greatly contributes to improving the measurement accuracy of the liquid concentration.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of one embodiment of the present invention, Fig. 2 is a view showing another embodiment, Fig. 3 is a view showing the actual measured values of the gauge pressure and the reduced volume of one embodiment of the present invention, and Fig. 4 is a correlation diagram of the data in Fig. 3. In the figure, 1 is a container, 2 is a lid, 5 is a bulging portion, 6 is a measuring tube, 8 is a pressure sensor, 9 is an inlet pipe, and 10 is an outlet pipe.

Claims (1)

[Scope of utility model registration request] A container for receiving a liquid to be measured, a means for receiving and discharging the liquid to be measured into the container, a lid for sealing an opening at an upper end of the container, and a tip penetrating the lid and inserted into the container. A measurement pipe having a diaphragm attached to the part, a measuring pipe containing a liquid and introducing pressurized air from an external air supply system, and a pressure sensor provided in the container to detect the liquid pressure in the container. , the amount of decrease in the liquid level in the measuring tube is measured after a period of time has elapsed from the time when the detected value by the pressure sensor reaches a predetermined pressure until the liquid to be measured in the container reaches an equilibrium state. A device for measuring the amount of bubbles in liquid.