JPS61120033A - Pressure history sensor - Google Patents

Abstract

PURPOSE:To obtain a simple pressure history sensor by injecting an aq. coloring material into a hydrophobic porous hollow system which is opened at one end as a pressure receiving port and is closed at the other end, and connecting the pressure receiving port to a pressure vessel thereby oozing the coloring material to the outside of the system under the set pressure value or above. CONSTITUTION:One end of the porous hollow system 1 manufactured of a hydrophobic resin such as polytetrafluoroethylene or PP is cut as the open pressure receiving port 2 and the other end is closed by thermal welding, etc. as the closed end 3. Such system 1 is contained into a tubular transparent vessel 7 by means 4, 5 for holding and connecting a pressure vessel and is connected to the pressure vessel. The penetration of the aq. coloring material 8 injected into the system 1 through the porous outside wall by receiving the pressure above the set value is observed and whether the excessive pressure is loaded or not is detected. Pressure releasing holes 6, 6' are preferably provided to the vessel 7. The simple and low-cost pressure history sensor is thus obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to pressure W! Regarding IM sensor. More specifically, the present invention relates to a pressure history sensor that can easily measure excessive pressure history.

[Conventional technology]

When performing a pressure test such as a permeation test on a separation membrane module, excessive pressure may be applied to the test object due to pressure fluctuations in the pressure source or some other cause, causing abnormalities there. When an abnormality occurs, whether it is due to overpressure or some other cause can only be determined by constantly measuring pressure and analyzing the records.

However, constant recording of pressure generally requires a device, a recorder, etc., and the measuring device is also expensive.

Furthermore, depending on the content of the test, highly accurate pressure control may not necessarily be necessary, so there are many cases where pressure is not constantly measured, such as when only visual confirmation is performed periodically.

[Problem that the invention seeks to solve]

In such cases, it would be advantageous to have a sensor that can easily recognize the presence of excessive pressure history, and the present invention seeks to provide a pressure history sensor that can be used easily. It is.

[Means for Solving the Problems] and [Operation] Accordingly, the present invention relates to a pressure fat layer sensor, and this pressure history sensor includes a hydrophobic porous material having an open pressure receiving port at one end and a closed end at the other end. A water-based colorant is injected into the hollow fiber, and pressure is applied to the inside of the hollow fiber from the open pressure receiving port connected to the pressure vessel side, and the water-based colorant oozes out to the outside of the hollow fiber, causing the pressure to exceed the set value. The occurrence can be visually recognized.

As described above, the pressure history sensor according to the present invention has a structure in which liquid penetrates into a thin film-like material having fine pores.
Although it utilizes the phenomenon of permeation, the oozing phenomenon caused by the pressure difference of liquid can be considered in two stages. The first stage is considered to be dominated by the ease with which the liquid wets the film material (this is indicated by the contact angle between the film and the liquid) and the difficulty in wetting the material, and at this stage there is a pressure side. Once the pressure level is reached, the liquid will enter the pores of the film.

The second stage is a stage in which the liquid that has entered the fine pores of the film moves through the pores corresponding to the thickness of the film and flows out to the low pressure side.

Here, if the film and liquid are selected to be difficult to wet with each other, the pressure when the liquid infiltrates and permeates through the pores is large in the first stage, and compared to this, the liquid passes through the pores in the second stage. This will reduce the amount of pressure necessary for this.

This can be explained as a phenomenon in which when liquid exceeds a certain level of pressure, it suddenly begins to pass through the film.

Therefore, the pressure WJiX sensor of the present invention is proposed based on the idea that it is only necessary to clearly detect the outflow of liquid when a certain set pressure is exceeded.

FIG. 1 of the drawings is a centerline vertical cross-sectional view showing a usage state of one embodiment of the pressure history sensor according to the present invention. One end of the porous hollow fiber 1 is made of a hydrophobic resin such as polytrifluoroethylene, poly(vinyl 77), poly(77) ethylene, polytrifluoroethylene, polyethylene, polypropylene, or aromatic polyimide. 2 forms an open end of the cut surface, and the other end 3 forms a closed end by heat fusion or other means.This hydrophobic porous hollow fiber is connected to a holding and pressure vessel connecting means. 4 and 5 are housed in a test tube-shaped transparent container 7 having a pressure relief hole 6.6' and connected to a pressure vessel (not shown).

As a result, the open pressure receiving ports of the hydrophobic porous hollow fibers are exposed to a pressurized atmosphere, and the aqueous colorant 8 injected into the hollow fibers is pressurized from above, but under normal pressure this The aqueous colorant does not pass through the micropores of the porous walls of the hollow fibers, so the outer walls of the hollow fibers remain uncolored. However, when pressure exceeds a certain level, the water-based colorant passes through the micropores and flows out.
The hollow fibers are colored with the coloring agent. In this way, it is visible to the eye that excessive pressure has been applied thereto.

As the water-based colorant, inorganic pigments that are easily dispersed in water, such as cobalt blue, ultramarine blue, manganese blue, pengara, cobalt red, tungsten blue, red lead, molybdenum red, and cobalt red, are used.

The critical pressure at which the aqueous coloring agent injected into the hydrophobic porous hollow fibers oozes out depends on the material and inner and outer diameters of the hollow fibers, the ease of wettability of the hollow material with the aqueous colorant, and the pore diameter of the hollow fiber micropores. However, it is generally easier to adjust the diameter of the micropores by appropriately selecting them.

It goes without saying that the hollow fibers made of the above-mentioned materials used need to be able to withstand hysteretic pressure, and this also determines the inner and outer diameters. Even if the inner and outer diameters are the same, the bursting pressure will differ depending on the material and the hole diameter, but in general, under pressures of 5 to 20 or less, the inner diameter is 1, and the outer diameter is about 21, and under pressures of 5 to 20, the inner diameter is 0. .51+! II, outer diameter 2
+RI of about 11 is used. There is no particular limit to the length, but from the viewpoint of ease of handling and color discrimination, approximately 2 to 5 crn is appropriate.

The pore diameter of the hollow fiber micropores is the most important factor, and the detected pressure is greatly influenced by this. Generally, the pore size is r
, when the detected pressure is P and A is a constant (determined by the material, the wettability of the paint, etc.), the relationship P-A/r holds true. Specifically, in the case of a detection pressure of 20 μm or less, a microporous hollow fiber having a pore diameter of about 0.5 to 10 μm is used.

〔Effect of the invention〕

The pressure history sensor according to the present invention can be manufactured at low cost by using a hydrophobic porous hollow fiber, and pressure history can be measured easily and with good reproducibility using this sensor.

Such a pressure 1a history sensor is used for pressurized permeation tests of separation membrane modules, pressurized tests of pressure vessels, etc. by utilizing such characteristics in vibration. When used in a separation membrane module, the hollow fibers are bundled with their openings at both ends aligned, and the hollow fibers are connected to each other at the openings at both ends, leaving a hollow part.
1 blocked hollow fiber group! The occlusion part is accommodated in the body, and the diffusion liquid or the supply liquid is supplied through the holes provided in the lids at both ends of the casing and the hollow fiber hollow parts, and the occlusion part is supplied through the holes provided at the opposite end of the casing and the occlusion part. In a diffusion dialysis device (Utility Model Application Publication No. 178-178-305) in which the supply liquid or the diffusion liquid is allowed to pass through the hollow fiber group gaps between the parts, the lid body on the liquid inlet side or the liquid inlet part It can be used by connecting it to itself using a pipe taper or the like. In this way, the pressure sensor is connected to the pressure device using a pressure sensor boat.

〔Example〕

Next, the present invention will be explained with reference to examples.

Example A porous hollow fiber made of polytetrafluoroethylene (Japan Voretex product Gore-Tex i inner diameter 111TII, outer diameter 2mm, length 2Crr1, pore diameter 1μm) was used, and blue ink was injected into it to form the illustrated embodiment. Pressure was applied according to the following. No change was observed in the hollow fibers up to a pressure of 3 or higher, but at higher pressures the hollow fibers became colored blue and oozing of blue ink was observed.

[Brief explanation of drawings]

FIG. 1 is a centerline vertical cross-sectional view showing a usage state of one embodiment of the pressure history sensor according to the present invention. (Explanation of symbols) 1...Hydrophobic porous hollow fiber 2...Hollow fiber open pressure receiving port 3...Hollow fiber closed end 7...Transparent container 8...Aqueous coloring agent

Claims (1)

[Claims] 1. Inject a water-based colorant into a hydrophobic porous hollow fiber with one end as an open pressure receiving port and the other end as a closed end, and apply pressure to the inside of the hollow fiber from the open pressure receiving port connected to the pressure vessel side. A pressure history sensor that allows the generation of pressure exceeding a set value to be visually confirmed due to the aqueous colorant exuding to the outside of the hollow fiber due to pressure.