JP3995820B2 - Measuring tank with defoaming function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a measurement tank used for a turbidimeter and the like, and relates to a measurement tank with a defoaming function having a function of removing bubbles contained in a test liquid.
[0002]
[Prior art]
In an analyzer such as a turbidimeter that detects the transmitted light and scattered light of sample water, bubbles are removed from the test solution prior to measurement so that accurate analysis is not hindered by bubbles contained in the test solution. It is necessary.
FIG. 2 shows a main part of a conventional turbidimeter based on the surface scattered light detection method. In the figure, a test liquid such as tap water sent from the test liquid inlet 101 is introduced into the defoaming tank 102 through the adjustment valve 106. In the defoaming tank 102, bubbles contained in the test liquid are removed by the buoyancy, and the test liquid after defoaming is introduced into the measurement tank 103. In addition, the test liquid in the defoaming tank 102 partially overflows and is discharged from the test liquid outlet 104. A drain valve 107 communicates with the defoaming tank 102.
[0003]
The measurement tank 103 is configured such that measurement light is irradiated from the instruction conversion unit 105 through the optical fiber 108 onto the surface of the test solution, and the surface scattered light is incident on the optical fiber 109. The instruction conversion unit 105 receives the surface scattered light, converts it into an electrical signal corresponding to the turbidity of the test liquid, and outputs it.
The test liquid overflowed in the measurement tank 103 is discharged from the test liquid outlet 104.
[0004]
In the turbidimeter having the above-described configuration, since the measuring tank 103 and the defoaming tank 102 in the preceding stage are provided separately and independently, it cannot be denied that the entire apparatus becomes large and the piping structure becomes complicated.
In view of this point, a turbidimeter in which a defoaming function is incorporated in a measurement tank has already been proposed.
[0005]
FIG. 3 is a cross-sectional view of the main part of a turbidimeter equipped with the above-described measurement tank with a defoaming function, which is a 90-degree scattered light detection method in which a photocell arranged in a test liquid detects scattered light. A turbidimeter is shown.
In the figure, 201 is a defoaming tank having a test liquid inlet 204, and an inner cylinder 202 is concentrically disposed therein.
[0006]
A large number of baffle plates 203 are provided at regular intervals between the defoaming tank 201 and the inner cylinder 202. These baffle plates 203 have a function of lengthening the flow path until the test liquid introduced from the test liquid inlet 204 flows into the inner cylinder 202, whereby the test liquid is allowed to flow into the inner cylinder 202. It is considered that defoaming is completed before it flows into
Further, an inflow port 206 into which the test solution flows is formed on the side surface of the lower end portion of the inner cylinder 202, and the test solution flows upward through the inner port 202 through the inflow port 206.
[0007]
A measurement chamber 207 is formed above the upper end opening of the inner cylinder 202, and scattered light due to turbidity of light incident on the test liquid from the lamp 209 above the liquid level 208 via the lens 210 is converted into the photocell 211. Detected by.
In the measurement chamber 207, a defoaming cylinder portion 212 is erected. The defoaming tube section 212 communicates with a space between the defoaming tank 201 and the inner cylinder 202, and defoaming is performed. The vent hole 213 at the upper part of the cylindrical portion 212 is opened above the liquid level 208.
[0008]
In this turbidimeter, bubbles in the test liquid rise due to buoyancy and adhere to the baffle plate 203 and the like while the test liquid descends in a zigzag manner in the defoaming tank 201. Then, these bubbles merge and grow to further increase the buoyancy, and are guided into the defoaming cylinder portion 212 and discharged from the vent hole 213 to the atmosphere.
[0009]
[Problems to be solved by the invention]
According to the prior art of FIG. 3, the defoaming tank 201, the inner cylinder 202, and the measurement chamber 207 are formed concentrically and integrally, so that the apparatus can be downsized compared to the structure of FIG.
However, there is no flow in the test liquid in the defoaming cylinder portion 212, and the discharge of the bubbles from the vent hole 213 depends solely on the buoyancy of the bubbles. That is, the structure shown in FIG. 3 has a problem that a sufficient defoaming effect cannot be obtained because there is no function of propelling the bubbles in the defoaming cylinder portion 212 with the test liquid and moving them to the vent hole 213.
In addition, the baffle plates 203 arranged in multiple stages may prevent the bubbles from rising quickly, and the flow path structure of the test solution by these baffle plates 203 is complicated, which causes high costs.
[0010]
Therefore, the present invention intends to provide a measurement tank with a defoaming function that enhances the defoaming effect than before and contributes to the improvement of measurement accuracy by an analyzer, and at the same time, enables the miniaturization of the entire measurement tank and the cost reduction. Is.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention described in claim 1 is a measurement tank for measuring a test liquid defoamed like a measurement tank of a turbidimeter,
The test liquid inlet test fluid is introduced is provided at the upper end side, and a degassing vessel which is open to the atmosphere,
A measuring cylinder that is arranged inside the defoaming tank and into which the test liquid flows from the inlet at the lower end ,
A first space which is attached to a packing for attaching the measuring tube to the housing and is surrounded by the defoaming tank, the measuring tube and the packing and a second space which is open to the atmosphere inside the housing are communicated with each other. A defoaming cylinder,
With
The measuring cylinder is arranged so that its axis is inclined with respect to a vertical line, and a part of the test liquid introduced into the defoaming tank can flow out through the defoaming cylinder, The outlet side of the defoaming tube part is directed in a direction away from the measurement tube .
[0012]
If a double structure with a measuring tube arranged inside the defoaming tank as in the present invention, compared to a structure in which a defoaming tank is separately arranged in the previous stage of the measuring tank, the entire apparatus is downsized and the piping structure is simplified. Is possible.
Also, by taking a sufficiently long distance between the test liquid inlet of the defoaming tank and the test liquid inlet of the measurement cylinder, the time until the test liquid flows into the measurement cylinder can be lengthened. In the meantime, by raising the bubbles in the defoaming tank, it is possible to prevent the bubbles from being mixed into the test liquid flowing into the measuring cylinder.
Furthermore, when at least the measuring cylinder is arranged so that its axis is inclined with respect to the vertical line, when the bubbles of the test liquid introduced into the defoaming tank rise due to buoyancy, the outer surface of the measuring cylinder in the way The movement distance until reaching the point is shortened, and by immediately combining with the bubbles adhering to the outer surface, it becomes possible to grow into larger bubbles. The buoyancy is increased by the growth of the bubbles, and the bubbles move quickly along the outer surface of the measurement tube to the upper side of the defoaming tank (at the open side of the atmosphere), so that defoaming is promoted. In addition, if the defoaming tank is formed concentrically with the measuring cylinder, the moving distance until the bubbles reach the inner surface of the defoaming tank is shortened, and the same effect can be obtained.
In addition, the structure in which the measuring tube is tilted with respect to the vertical line is such that, for example, in a surface-scattered light detection type analyzer, the refracted light of the measuring light incident on the surface of the test solution from an oblique direction is approximately Enable to guide in parallel. As a result, it is possible to prevent the refracted light from being reflected from the inner surface of the measuring tube and becoming stray light.
[0013]
In the present invention, a defoaming flow path for discharging the test liquid through the defoaming cylinder portion is formed in addition to the measurement flow path for the test liquid from the defoaming tank toward the measurement cylinder. . In other words, the air bubbles that have risen above the defoaming tank are not only buoyant, but are also carried by the flow of the test liquid toward the defoaming cylinder and are discharged through the defoaming cylinder. Defoaming in a good short time becomes possible.
[0014]
Here, the pre-Symbol defoaming tube portion, may turn away the exit side from the measurement tube. This is to prevent the surface of the sample liquid in the measuring cylinder from undulating due to the ripples when a large bubble discharged from the defoaming cylinder is ruptured. This is a useful structure.
[0015]
In addition, as described in claim 2 , a rough surface is formed on both the inner surface of the defoaming tank and the outer surface of the measuring tube, or any one of the wetted surfaces by sanding or sandblasting. This facilitates trapping of bubbles on these surfaces and contributes to the growth of larger bubbles by coalescence.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a main part of a measurement tank according to an embodiment. This measurement tank includes a defoaming tank 10 and a measurement cylinder 20 that substantially form a double cylinder structure, and these members 10 and 20 and A light emitting section 34 and a housing 31 that holds the light receiving section 35 are provided.
[0017]
The defoaming tank 10 is formed of a substantially bottomed cylindrical plastic molded product. A test liquid inlet 11 is provided on the side surface of the upper end portion, and a convex portion 12 is formed on the inner surface of the bottom portion. In addition, almost all the inner surface 13 of the defoaming tank 10 is subjected to wrinkle processing at the time of molding, so that an appropriate rough surface is formed. The defoaming tank 10 is attached to a sleeve 32 formed at the bottom of the housing 31.
[0018]
On the other hand, the cylindrical measuring tube 20 is disposed concentrically inside the defoaming tank 10 via a packing 23 attached to the sleeve 32 in a watertight manner. The opening 21 at the upper end of the measuring cylinder 20 is cut off by a plane that is not orthogonal to the axis of the measuring cylinder 20, and the surface of the test solution S on this plane is surface scattered light by the light emitting unit 34 and the light receiving unit 35. Measurement position. The test liquid flows into the measuring cylinder 20 from the lower inlet 26.
In addition, a stopper 22 is installed at the bottom of the measurement tube 20, and the measurement tube 20 is positioned by the stopper 22 coming into contact with the convex portion 12 of the defoaming tank 10.
The measuring cylinder 20 is formed by cutting a pipe such as vinyl chloride, and an appropriate rough surface is formed on almost the entire outer surface 25 by sandblasting or the like.
[0019]
The axes of the defoaming tank 10 and the measuring cylinder 20 do not coincide with the vertical line, and are arranged so as to intersect the vertical line at a predetermined angle. Such an arrangement is the same in the measurement tank 103 shown in FIG. 2, but the refracted light of the measurement light incident on the surface of the test solution S from an oblique direction is directed in a direction substantially parallel to the axis of the measurement cylinder 20. This is due to the intention to go. In other words, when the refracted light hits the inner surface of the measuring tube 20 and is reflected, the reflected light becomes stray light and adversely affects the scattered light measurement, which is a structure for preventing this.
Furthermore, the inclined arrangement structure of the defoaming tank 10 and the measuring cylinder 20 is extremely significant in terms of the defoaming effect, and the reason will be described later.
[0020]
A defoaming cylinder portion 24 is attached to the packing 23 that attaches the measurement cylinder 20 to the housing 31. The defoaming cylinder portion 24 includes a first space surrounded by the defoaming tank 10, the measurement cylinder 20 and the packing 23, and a second space outside the packing 23 (an internal space of the housing 31 opened to the atmosphere). The defoaming flow path is configured to discharge bubbles contained in the test liquid in the first space into the housing 31 together with the test liquid.
The upper half of the defoaming tube portion 24 is bent outward so as to move away from the measurement tube 20. This is to prevent the surface of the test liquid S in the measurement cylinder 20 from being waved and unstable due to the ripples when a large bubble is discharged from the outlet of the defoaming cylinder 24 and ruptures.
A test liquid outlet 33 is formed at the lower end of the housing 31 to discharge the test liquid overflowed from the opening 21 and the defoaming cylinder 24 of the measurement cylinder 20.
[0021]
Next, the operation of this embodiment will be described.
Now, in a state where the measurement cylinder 20 and the defoaming tank 10 are filled with the test liquid, the test liquid such as tap water introduced into the defoaming tank 10 from the test liquid inlet 11 is around the measurement cylinder 20. As a whole, it goes to the inlet 26 at the lower end of the measuring cylinder 20. Meanwhile, since the rough surface is formed on the inner surface 13 of the defoaming tank 10 and the outer surface 25 of the measuring tube 20, the fine bubbles contained in the test liquid are easily trapped by the uneven portions of these rough surfaces. . In particular, by taking a certain distance between the test solution inlet 11 and the inlet 26 of the measuring tube 20 to some extent, most of the bubbles are made by the rough surface until the test solution reaches the inlet 26. Can be trapped.
[0022]
The trapped fine bubbles eventually coalesce and grow to become large bubbles, which move upward due to their buoyancy. Here, as described above, in the present embodiment, the defoaming tank 10 and the measurement cylinder 20 are disposed so as to be inclined with respect to the vertical line. The moving distance until reaching the inner surface 13 of the foam tank 10 is short. Accordingly, the bubbles adhering to the inner and outer surfaces 13 and 25 immediately merge with each other, and the growth to larger bubbles is promoted. The buoyancy is increased by the growth of the bubbles, and the bubbles quickly move along the inner and outer surfaces 13 and 25 and above the defoaming tank 10.
[0023]
Further, since the flow of the test liquid from the test liquid inlet 11 toward the defoaming cylinder portion 24 is generated inside the defoaming tank 10, the bubbles that have risen above the defoaming tank 10 are detected by this test. It rides on the flow of the liquid and is sent to the defoaming cylinder portion 24 and then released to the atmosphere inside the housing 31. That is, in this embodiment, a defoaming flow path from the test liquid inlet 11 toward the defoaming cylinder portion 24 is formed separately from the measurement flow path from the test liquid inlet 11 toward the measurement cylinder 20. Since the propelling force is given to the bubbles by the test liquid flowing through the defoaming cylinder portion 24, the defoaming can be efficiently performed in a short time.
[0024]
The test liquid from which bubbles have been removed before reaching the inlet 26 of the measurement cylinder 20 as described above flows upward in the measurement cylinder 20 and overflows to the outside from the test liquid outlet 33 through the piping. Is discharged. Further, the test liquid overflowing from the defoaming cylinder 24 is also discharged together.
By appropriately adjusting the flow rate of the test solution to stabilize the surface of the test solution at the opening 21 of the measuring tube 20, and measuring the surface scattered light intensity in this state, the turbidity corresponding to the turbidity concentration in the test solution is obtained. It is possible to measure the degree.
In addition, the light from the light emission part 34 is shaped by combining a slit and a plurality of lenses so as to be incident on the surface of the test solution in a circular shape instead of an elliptical shape. This is because the light beam refracted on the surface of the test solution is kept within a certain distance from the inner surface of the measurement tube 20 while ensuring the incident area for measurement, so that the refracted light is reflected inside the measurement tube 20. This is to prevent stray light from hitting the surface.
[0025]
In this embodiment, the case where the present invention is applied to a turbidimeter using a surface scattered light detection method has been described. However, the present invention is applicable to a turbidimeter using a 90 ° scattered light detection method or a transmitted light detection method, and other test liquids. Can be applied to various analyzers that need to be degassed and measured.
[0026]
【The invention's effect】
As described above, according to the present invention, since the defoaming tank and the measurement cylinder are integrated by a double structure, the entire apparatus can be reduced in size and the piping structure can be simplified. By securing the bubble channel and roughening the wetted surface, it is possible to efficiently trap, grow, move and discharge bubbles in a short time. Thereby, bubbles in the test solution can be reliably removed, and the measurement accuracy of the water quality analyzer and the like can be greatly improved.
Moreover, since it is not necessary to create a complicated flow path structure using a conventional baffle plate or the like in order to enhance the defoaming effect, the structure of the measurement tank itself can be simplified and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a main part of the prior art.
FIG. 3 is a cross-sectional view showing a main part of the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Defoaming tank 11 Test liquid inlet 12 Convex part 13 Inner surface 20 Measuring pipe | tube 21 Opening part 22 Stopper 23 Packing 24 Defoaming pipe part 25 Outer surface 26 Inlet 31 Housing 32 Sleeve 33 Test liquid outlet 34 Light emission part 35 Light reception Part S Test solution

Claims (2)

In a measurement tank for measuring the defoamed test liquid,
A defoaming tank in which a test liquid inlet into which the test liquid is introduced is provided on the side surface of the upper end and is open to the atmosphere;
A measuring cylinder that is arranged inside the defoaming tank and into which the test liquid flows from the inlet at the lower end ,
A first space which is attached to a packing for attaching the measuring tube to the housing and is surrounded by the defoaming tank, the measuring tube and the packing and a second space which is open to the atmosphere inside the housing are communicated with each other. A defoaming cylinder,
With
The measuring cylinder is arranged so that its axis is inclined with respect to a vertical line, and a part of the test liquid introduced into the defoaming tank can flow out through the defoaming cylinder, A measuring tank with a defoaming function, characterized in that an outlet side of the defoaming tube portion is directed in a direction away from the measuring tube . In the measurement tank with a defoaming function according to claim 1,
A measuring tank with a defoaming function , wherein a rough surface is formed on both or either one of the inner surface of the defoaming tank and the outer surface of the measuring tube .

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