JPH06341945A - Liquid observation window - Google Patents

Abstract

PURPOSE:To provide a liquid observation window which does not become dirty due to component in liquid. CONSTITUTION:A recessed section is provided on the outer wall of a case to form a small chamber 1, and an observation window 5, a light projecting window 6, and a light receiving window 7 are provided on this small chamber 1. Light is projected on a liquid level 3a by a projector 8 via the light projecting window 6, and the reflected light is received by a photodiode PD2 via the light receiving window 7. A compressor 11 is controlled via a control circuit 10 to feed air into the small chamber 1 so that the liquid level 3a becomes constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid observation window provided in an optical device for observing a liquid such as inside a reaction tank.

[0002]

2. Description of the Related Art In a conventional liquid observation window of this type, since the liquid is in contact with the window, contamination by the components in the liquid poses a problem, and it has been wiped with a wiper or the like.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a liquid observation window in which the window is clean and does not require any wiping.

[0004]

The present invention has been made to solve the above problems, and the first invention provides a small room between a window and a liquid and fills the small room with gas. The liquid observation window is characterized in that a gas layer is provided between the window and the liquid.

A second aspect of the present invention is a liquid observation window according to the first aspect of the present invention, which is provided with a pressure adjusting means in a small chamber in which the boundary surface between liquid and gas is always a stable flat surface or curved surface. Is. In this case, a means for detecting the pressure of the liquid around the liquid observation window and the differential pressure in the small chamber is used, or an optical means for directly detecting the fluctuation of the gas-liquid interface is used.

A third aspect of the present invention is a liquid observation window according to the first aspect of the present invention, which is provided with a device for constantly adjusting the atmospheric pressure in the small chamber to be higher than the pressure of the liquid. The liquid observation window is characterized in that it is released into the liquid by.

A fourth invention is a liquid observation window according to the first invention, characterized in that the inner surface of the small chamber is coated with a material having poor wettability.

[0008]

According to the first aspect of the invention, since the gas layer is provided between the window and the liquid and the surface of the window does not come into contact with the liquid, the component in the liquid does not stain the window.

In the case of the basic structure according to the first aspect of the invention, the boundary surface between the liquid and the gas facing the window may fluctuate. Therefore, in the second invention, the boundary is maintained so as to keep the optical constant. It improves the stability of observations made by equipment.

The third aspect of the invention is different from the second aspect of the invention in that the boundary surface is not always constant, but similarly, the window is not stained by the components in the liquid. And in the case of the present invention, the generation of bubbles,
A method such as synchronizing growth, emission and optical observation, and comparing by maximum optical value are required, but this method may be advantageous in practical use and design.

The fourth aspect of the invention has the function of preventing the liquid from entering the small chamber and holding the gas layer.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment, in which 1 is a small room provided with a sufficiently small recess provided on the outer wall of a case 2 accommodating optical observation equipment.

The inner surface of the small chamber 1 is covered with a material 4 having poor wettability such as Teflon or lacquer, and an observation window 5, a light projecting window 6 and a light receiving window 7 are provided.

A light projecting device 8 is provided with a lamp 8a and a lens 8b. Light is projected onto the liquid surface through a light projecting window 6, and the reflected light is incident on a light receiving window 7 and passes through a lens 9 to a photodiode PD2. Is detected by the control circuit 10 and the compressor 11 is controlled by the control circuit 10 so that the liquid surface 3a is always maintained in a constant state (flat surface or curved surface).

The state of the liquid surface 3a (in this case, the amount of light) is detected by the photodiode PD1 via the lens 12 and is displayed on the meter 14 via the amplification circuit 13 as in the conventional case.

When the case 2 constructed as described above is put into a liquid, a boundary between the liquid 3 and a gas is formed in the opening of the small chamber 1 due to the surface tension of the liquid 3, and the liquid is present in the small chamber. Three
Does not come in.

However, this boundary surface 3a is deformed by the pressure fluctuation of the liquid and the atmospheric pressure in the small chamber, and the optical observation value changes, but this device controls the pressure in the small chamber in accordance with the pressure of the liquid. To do.

That is, the light emitted from the light source (lamp 8a) is reflected by the boundary surface 3a and received by the photodiode PD2,
A servo system that controls the compressor 11 so that the amount of received light becomes constant controls so that the boundary surface is kept constant.

If the wettability of the inner surface of the small chamber 1 to the observed liquid is good, the liquid 3 will enter the small chamber due to the wetness, but if it is covered with a material having poor wettability as in the first embodiment. Liquid does not enter the small room, and the observation window 5
Is blocked by a gas layer to prevent contamination.

FIG. 2 shows the second embodiment. Unlike the first embodiment, the servo system is not incorporated, and the small chamber 1 and the inside of the case 2 are communicated with each other through the through hole 15, and the atmospheric pressure in the case 2 is known. By making the pressure higher than the liquid pressure in the apparatus, a gas layer is constantly blown out to form a gas layer between the observation window 5 and the liquid 3 to prevent the window from being contaminated by the components in the liquid.

In this case, the optical characteristics observed through the observation window 5 change. For example, when the present invention is applied to a liquid light quantity monitor, the maximum value of the received light quantity is the measured light quantity, depending on the optical system. do it.

[0022]

According to the present invention, the observation window can be shielded from the liquid to prevent the observation window from being contaminated by the components in the liquid.

Through the observation window according to the present invention, direct observation of the liquid by a camera or CCD camera, absorption observation by reflected light, and two observation windows are arranged so as to face each other, one for projecting light and the other for projecting light. It can be suitably used for observation of transmission for light reception and observation of attenuation of light by an intermediate liquid or absorption of a specific wavelength.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a second embodiment of the present invention.

[Explanation of symbols]

 1 Small room 2 Case 3 Liquid 4 Material with poor wettability 5 Observation window 6 Light emitting window 7 Light receiving window 8 Light emitting device 9 Lens 10 Control circuit 11 Compressor 12 Lens 13 Widening circuit 14 Meter 15 Through hole

Claims (4)

[Claims] 1. A liquid observation window, characterized in that a small chamber is provided between the window and the liquid, and the small chamber is filled with gas to provide a gas layer between the window and the liquid. 2. The liquid observation window according to claim 1, further comprising a pressure adjusting means in the small chamber for always making a boundary surface between the liquid and the gas a stable flat surface or a curved surface. 3. The liquid observation window according to claim 1, wherein a device for adjusting the atmospheric pressure in the small chamber to be always higher than the pressure of the liquid is provided to discharge bubbles into the liquid. 4. The liquid observation window according to claim 1, wherein the inner surface of the small chamber is covered with a material having poor wettability.