JPH08261910A - Measuring device for measuring one of at least two volatile components of liquid,especially fermention liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent failure of a measuring sensor due to mechanical damage of an osmosis membrane by suppressing the measurement error due to the effect of other volatile component, not measured at the time of measuring one volatile component in a fermented liquid, through a simple means. SOLUTION: The support for an osmosis membrane forms a plug 5 for closing the opening 4 of casing covered with an osmosis membrane 6 abutting against one end face of the plug 5. The osmosis membrane 6 comprises at least two layers exhibiting different osmotic resistance to the volatile component.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The invention relates to a measuring device for measuring one of at least two volatile constituents of a liquor, in particular a fermentation liquor, which comprises a casing and said one arranged inside said casing. A sensor for measuring volatile components,
A carrier gas passage provided in the support, which has an osmotic membrane in contact with the support, the permeable membrane being open to this, the carrier gas passage being the carrier gas. Of the type connected to the supply conduit and to the sensor via a carrier gas discharge conduit.

[0002]

A known measuring device of this type has a cylindrical support core which has penetrated into a fermentation vessel for a hose-shaped osmotic membrane, said hose-shaped osmotic membrane being It surrounds the threads of the support core which serve as carrier gas passages. This thread is connected at one end to a carrier gas supply conduit and, at the other end, to an axial hole in the support core, which axial hole serves to expel the carrier gas and opens into the area of the measuring sensor. There is. Volatile components from the fermentation liquor flowing around the support core with osmosis membrane permeate the osmosis membrane,
The carrier gas is supplied to the measuring sensor through the threads of the supporting core and its axial holes, which measuring sensor
The volatile component whose quantity is to be measured is determined, for example, on the basis of the electrical resistance related to the concentration of this component. The disadvantage of this known measuring device is, on the one hand, that, when measuring one of the two or more volatile constituents of the fermentation liquor, the result of the measurement is that it is not the object of measurement in the carrier gas, or that it is not measured. Due to the different amounts of the components of the, the osmotic membrane is, on the other hand, often mechanically damaged in the casing when the casing breaks despite the placement of the support core, and fermentation of the damaged osmotic membrane. The fermented liquid is directly loaded onto the measurement sensor from a portion that is not liquid-tight with respect to the liquid, which may cause the measurement sensor to malfunction.

[0003]

SUMMARY OF THE INVENTION The object of the invention is to avoid the above-mentioned drawbacks of the prior art, and of the type mentioned at the outset,
A measuring device for measuring one of at least two volatile constituents in a liquor, in particular a fermented liquor, by means of a simple construction, reduces the measurement error due to unmeasured volatile constituents to a permissible value and the machine of a permeable membrane The purpose is to eliminate the risk of measurement sensor failure due to mechanical damage.

[0004]

SUMMARY OF THE INVENTION According to the invention, the object is to provide a support body which forms a closure plug for the casing opening, the casing opening being provided by a permeable membrane which abuts against one end face of the closure plug. This is solved by the fact that the overlying and permeable membrane consists of at least two layers which differ in their permeation resistance to volatile constituents.

The structure of the permeation membrane, which consists of at least two layers with different permeation resistances to the volatile constituents of the liquid, correlates the measured value of the constituent to be measured with the respective quantity of the other constituents. , Reduce to an acceptable degree. Despite the fact that the combined action of these different layers with respect to measuring one component of the plurality of components with a sensor is certain, the cooperating action of the laminated membrane leading to such a result is No further details can be given. There is clearly an opposite effect of the individual components on the concentration of the components in the carrier gas, so that the association between different and varying concentrations of the individual volatile components in the liquid and the measurement is further reduced. It Furthermore, the laminated structure of the permeable membrane provides high safety against liquid intrusion into the carrier gas passage. This is because when the osmotic membrane is mechanically damaged, only one layer is damaged first, in other words, both layers are damaged and a higher mechanical load is required for the liquid to enter. This is because it is necessary to cover the permeable membrane. Furthermore, the support of the osmotic membrane is designed as a closure plug of the casing opening, resulting in a simple and compact structural unit which is particularly suitable for receiving permeable membranes of laminated construction. This is because in this case it is sufficient to simply superimpose the individual permeation membrane layers, which usually consist of one membrane, respectively, and to fasten them to the casing opening by means of a closure plug. These layers preferably extend flat,
However, because of the hydraulic pressure exerted on the end face of the closure, the manner in which these layers extend is related to the shape of this end face of the closure.

The layer materials of the different permeable membranes should be selected taking into account the respective volatile constituents in the liquid. For acetic acid fermentation, that is, for controlling it, it is necessary to define the alcohol content, that is, the ethanol concentration, but when measuring this ethanol concentration with a sensor, if only one permeation film is used. In order to monitor acetic acid fermentation, in which the measurement value is sometimes inaccurate due to the concentration of acetic acid, it is advantageous to use an osmotic membrane composed of a layer of silicon and a layer of polytetrafluoroethylene. . Such an osmotic membrane material reduces the influence of the occasional acetic acid concentration on the alcohol determination to an acceptable level for the control of acetic acid fermentation. The measuring device according to the invention can be configured as a device that can be placed in the liquid container or can be arranged on the outer wall of the liquid container, in which latter case the outer wall of the liquid container is passed through to the measuring device. Must have an opening. In order to be able to close this passage opening of the liquid container in a liquid-tight manner during maintenance or installation work of the measuring device, the casing can be adjustably mounted on the bottom plate on the side of the casing opening with the permeation membrane. Has a passage opening cooperating with the casing opening, and at least relative to the casing,
It is movable in the adjusting direction by a distance corresponding to the diameter of the passage opening. If the liquid container has this bottom plate, the passage opening of the bottom plate can be closed by the casing wall by simply moving the casing with respect to this bottom plate,
In this case, the closure is moved out of the range of the passage opening in the bottom plate, and thus also without the risk of the liquid in the container escaping through the casing of the measuring device, for example for changing the osmotic membrane. The body can be removed from the casing.

In order to reduce the risk of damaging the sensor by liquids that have entered the measuring device casing via the carrier gas passage of the closure during a device failure, the sensor is located above the closure in the casing. It can be arranged so that the measuring device can be switched off in a timely manner when detecting a fault. The fault detection itself can be carried out by means of a liquid detector, which can be provided in a branch conduit of the carrier gas discharge conduit extending downwards from the closure.

Sensor measurements of volatile constituents in a liquid are also related to temperature. In order to successfully compensate for the influence of temperature on the measurement of the sensor, the liquid temperature in the direct range of the measuring device must be detected as a reference. To meet this need in a simple manner without inserting a special temperature detector in the liquid container, a temperature detector for compensating for the temperature during sensor measurement can be inserted in the closure plug.

The measuring apparatus according to the present invention has been used in a fermentation process such as acetic acid fermentation. However, the measuring apparatus according to the present invention is not limited to such an application and can be used in a liquid. It can be used to a wide advantage when it is desired to quantitatively define one of the volatile components of the above regardless of the concentration of the other components.

[0010]

The measuring device shown in FIGS. 1 to 3 has a casing 2 with a removable lid 1 in which the fermentation liquor is carried by a carrier gas. A sensor 3 is provided for measuring one volatile component, for example ethyl alcohol in acetic acid fermentation. To receive the volatile constituents to be measured, there is provided a casing opening 4 with a closure plug 5, which is covered on its outer end face with a permeable membrane 6 in the form of a spiral groove. Forming a carrier gas passage 7,
The spiral groove is connected in the region of its central inlet end via an axial bore 8 to a feed conduit 9 and in the region of its outer outlet end via an axial bore 10 to a discharge conduit 11 for carrier gas. The exhaust conduit 11 extends to the sensor 3 from which the carrier gas with volatile constituents is sucked out of the casing 3 via the exhaust gas conduit 12. The discharge conduit 11 for the gas carrier forms in this case a branch conduit 11a extending downwardly from the closure plug 5, which has a liquid detector 13. In order to be able to shut off the measuring device in the event of a failure before the sensor is damaged under the load of liquid, said liquid detector 1
It is possible to detect that the liquid passing through the osmotic membrane 6 is interrupted by 3.

According to FIG. 3, the permeation membrane 6 consists of two layers 6a, 6b, each formed by one membrane, which are in the region of the casing opening 4 an elastic ring-shaped shoulder 14 and a closure plug 5. Is tightly closed in a liquid-tight manner and is supported on the outer end surface of the closure plug against the fermentation liquor pressure applied to the casing opening 4. The tightening force for tightening the osmotic membrane 6 is in this case provided by a tightening screw 15 acting on a pressing piece 16 which is hooked on the closure plug 5.

What is important in the laminated structure of the permeation membrane 6 is that the individual layers 6a, 6b have different permeation resistances to the volatile components of the fermentation liquor which impinge on them. For this purpose, one of the two layers 6a, 6b is made of silicon and the other is made of polytetrafluoroethylene, which is particularly effective in connection with the determination of alcohol concentration in acetic acid fermentation. It was The permeation membrane 6 is permeated not only by alcohol but also by acetic acid, which is also volatile, and the acetic acid also affects the electrical resistance of the sensor 3 used to measure the alcohol concentration, and as a result, the fermentation liquid. There may be an error in the measured value of alcohol content of. The vertical axis indicates the measurement error vol. % Alcohol is plotted, and the horizontal axis indicates the acetic acid content in the fermentation liquid in g /
FIG. 4, plotted at 100 mL, shows typical measurement error curves at different alcohol concentrations when using exclusively a single layer osmosis membrane. For example 0.0
8 vol. The curve A, indicated by the dashed line, for a small alcohol content of%, initially shows a negative measurement error that decreases with increasing acetic acid content, and then a positive measurement error that increases with acetic acid content. Show. 4.09 vol. Curve B, which is shown as a solid line for a relatively high alcohol content of%, shows an inverse measuring error course. 2.03vo
l. Only curve C, which is shown with a dash-dotted line with an intermediate alcohol content of%, shows a measurement error course which is relatively independent of acetic acid concentration. For the measurement error curves A, B and C, when one coating is made of silicon and the other coating is made of polytetrafluoroethylene, a two-layer permeation membrane is used, and the other measurement conditions are the same. 5 shows curves a, b and c corresponding to curves A, B and C in FIG.
As can be seen, the measurement error is extremely small.

According to the illustrated embodiment, the measuring device is arranged on the peripheral wall 17 of the fermentation vessel via a bottom plate 18, which also serves as a connecting plate, which covers the casing opening 4 from the fermentation vessel. It has a passage opening 19 for passing the liquid to the permeable membrane 6. Due to the fixing screw 21 engaged in the slot 20, the casing 2 of the measuring device is fixed to the bottom plate 1
8 is slidably guided with respect to 8, so that the casing 2 can be moved with the fixing screw 21 locked to the point where the casing 2 closes the passage opening 19 of the bottom plate 18. And the closure plug 5
Can be removed from the casing 2 without fear of liquid outflow from the fermentation vessel.

Since the measured amount of volatile constituents in the fermentation liquor is related to the liquid temperature, the liquid temperature in the range of the permeable membrane should be detected as much as possible in order to compensate for the influence of temperature on the measurement. For this purpose, it is advantageous to insert the temperature detector 22 into the closure 5 which takes the liquid temperature.

[Brief description of drawings]

FIG. 1 is a view of a measuring device of the present invention for measuring one of at least two volatile components in a fermentation broth, viewed from an end surface side with a casing lid removed.

FIG. 2 is a sectional view of the same device taken along line II-II of FIG.

FIG. 3 is an enlarged cross-sectional view showing a part of a permeable membrane that abuts the closure plug.

FIG. 4 is a diagram showing a time-dependent curve of measurement error occurring in relation to acetic acid concentration at various alcohol concentrations in alcohol measurement of acetic acid fermentation by a known measuring device.

FIG. 5 is a diagram showing a curve of measurement error corresponding to FIG. 4 when the measuring device of the present invention is used.

[Explanation of symbols]

 1 Lid 2 Casing 3 Sensor 4 Casing Opening 5 Closing Plug 6 Penetration Membrane 6a, 6b Layer 7 Carrier Gas Passage 8 Axial Hole 9 Supply Conduit 10 Axial Hole 11 Exhaust Conduit 11a Branch Conduit 12 Exhaust Conduit 13 Liquid Detector 14 Ring Shoulder 15 Tightening screw 16 Pressing piece

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G01N 27/12 G01N 27/12 B // G01N 27/04 27/04 Z

Claims (6)

[Claims] 1. A measuring device for measuring one of at least two volatile constituents of a liquor, in particular a fermentation liquor, comprising a casing and said one volatile constituent arranged in said casing. A carrier gas passage provided in the support, the carrier gas passage being open to the sensor and a sensor for In the type in which the gas passage is connected to the carrier gas supply conduit and to the sensor via the carrier gas discharge conduit, the support forms the closure plug (5) of the casing opening (4), The casing opening (4) is covered by a permeable membrane (6) which abuts one end face of the closure plug (5), and the permeable membrane (6).
Comprises at least two layers (6a, 6b) having different osmotic resistance to volatile components,
Measuring device for measuring one of at least two volatile constituents of a liquor, in particular a fermentation liquor. 2. Measuring device according to claim 1, characterized in that one layer (6a) of the permeation membrane (6) consists of silicon and the other layer (6b) consists of polytetrafluoroethylene. . 3. The casing (2) is adjustably mounted on the bottom plate (18) on the side of the casing opening (4) having the permeation membrane (6), which bottom plate (18). Characterized in that it has a passage opening (19) cooperating with it and is movable relative to the casing (2) at least a distance corresponding to the diameter of the passage opening (19) in the adjusting direction. The measuring device according to claim 1 or 2. 4. Measuring device according to claim 1, characterized in that the sensor (3) is arranged above the closure plug (5) in the casing (2). . 5. Carrier gas discharge conduit (11), characterized in that it comprises a branch conduit (11a) with a liquid detector (13) extending downwardly from the closure (5). The measuring device according to any one of 1 to 4. 6. A temperature detector (22) for compensating for the influence of the temperature during the measurement of the sensor is inserted in the closure body (5), characterized in that The measuring device according to claim 1.