JPS6140555A - Method and apparatus for measuring water content of lubricant of the like - Google Patents

Abstract

PURPOSE:To measure water in a lubricant accurately, by heating a mixture of a solvent for making an azeotrope with water and a sample near the azeotropic point to measure the resulting distilate gas by Karl Fischer's method after introduced into a titration cell. CONSTITUTION:A heating furnace 3 is kept at a specified temperature (80 deg.-140 deg.) beforehand and a dry gas flows at a fixed flow rate from a gas source 7. A required amount of (a) solvent (e.g. benzene, toluene and xylene used for making an azeotrope with water) is prepared in a column 8, after the lowering of the heating furnace 3, it is injected into an airtight sample container 1 by a dry gas/solvent introduction means 4 and then, a dry gas is injected. Then, several (g) of a sample is injected thereinto at a sample injection port 1a and the heating furnace 3 is lifted to heat the container 1. When the temperature of the container 1 reaches the azeotropic point, water in the sample vaporizes accompanied by the solvent and carried on the dry gas to the titration cell 13. A Karl-Fischer coulometric is performed with the titration cell 13 to determine water.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for measuring moisture contained in lubricating oil, etc.
The present invention relates to a measuring device used to carry out the method.

[Conventional technology]

The amount of water contained in a lubricating oil is considered to be one of the important items in evaluating the performance of the lubricating oil, so it is necessary to know the content accurately.

Conventionally, as methods for determining the water content in lubricating oil, (a) distillation method, (b) direct Karl Fischer method, (c) vaporization indirect Karl Fischer method, etc. have been proposed and practiced.

However, the distillation method described in (a) above uses an appropriate solvent that forms an azeotrope with water in order to prevent other components that have the same effect as the water in the sample from coming out during measurement. Since it distills water, it is not suitable for measuring trace amounts of water.

An improved method of measuring Mizoyama solution using the Karl Fischer method is also known, but this method has the disadvantage that the amount of Mizoyama solution is large, resulting in large consumption of reagents.

In addition, in the method mentioned above, the sample is dissolved in an appropriate solvent and measured directly using the Karl-Fuscher method, but as is well known, lubricating oils contain additives or other components may be mixed in due to use. Since the additives and decomposition products such as aldehydes and ketones react directly with the reagents, they are exaggerated on the measurement scale, which hinders accurate measurements.

Furthermore, in method (c), the sample is heated to 60 to 80'C, dry N2 gas is bubbled through it to vaporize moisture, and this is absorbed into a suitable solvent, which is then measured using the Karl Fischer method. However, it has the disadvantage that measurement takes a considerable amount of time.

[Problem that the invention seeks to solve]

The first invention of the present application is based on the results of studies conducted in view of the unavoidable defects of the conventional measurement methods described above. etc.), add this to a small amount of sample, such as a few ml, or a few grams or less,
Regarding this, while heating it to around its azeotropic point, a dry gas such as N2 is passed through to distill water together with the solvent, and this Mizoyama gas is introduced into a titration cell using the dry gas as a carrier and subjected to the Karl Fischer method. The purpose of this study is to propose a method of measurement that can be completed in a short period of time, at low temperatures, with high accuracy, and without any problems even in the measurement of trace amounts of moisture.

In the second invention of the present application, in order to realize the above-mentioned novel method, an airtight sample S is provided with a sample injection port and a heating means.
A drying gas and solvent introducing means capable of selectively supplying drying gas or dehydrated solvent is connected to the vessel, and
A titration cell of a Karl Fischer coulometric titrator is connected to the airtight sample container via a heat-retainable distillation tube.
The purpose is to configure the moisture measuring device so that the measuring method described above can be carried out efficiently.

[Means for solving problems]

In the first invention of the present application, in order to achieve the above object, a small amount of a sample such as lubricating oil and a small amount of a dehydrated solvent that forms an azeotrope with water and dissolves the sample are placed in an airtight container. This is heated to near its azeotropic point while being heated with N2
By introducing a dry gas such as the above into the airtight container, the water in the sample is distilled out together with the solvent, and this Mizoyama gas is introduced into the titration cell using the dry gas as a carrier, where it is curled. The present invention aims to provide a method for measuring water contained in lubricating oil, etc., characterized in that the measurement is carried out by the Fuscher method.

Further, in order to achieve the above object, the second invention includes an airtight sample container having a sample injection port, and a heat source that heats the airtight sample container to a set temperature from the outside,
The airtight sample container must be filled with a dry gas such as N2, or
A drying gas and solvent introduction means that can selectively supply any of the dehydrated solvents are connected, and the sample container and the titration cell of the Karl Fischer coulometric titration device are connected by a distillation tube that can be kept warm. The present invention aims to provide a device for measuring moisture contained in lubricating oil, etc., which is characterized in that the two devices are connected to each other.

〔Example〕

Before explaining the method according to the first aspect of the present application, an embodiment of the measuring device according to the second invention will be described in detail with reference to the drawings. 1
is made of glass, for example, and has an internal volume of 25 ml or less, and has a sample inlet 1a and a safety valve 1b on its shoulder, and a drain port 1d that is opened and closed by a cock 1C on its bottom. The opening 1e is tightly fitted and held in the support part 2.

The sample injection port 1a has a threaded cylinder 1a' protruding from the shoulder.
At the open end of the sample container 1, a silicone rubber plate 1a" having a wall thickness of about 3 mm is tightened with a cap nut 13" to maintain the airtightness inside the sample container 1. The injection needle is inserted into the silicone rubber plate 1a'' by a syringe.

The safety valve 1b is provided to prepare for bumping.

In addition, a heating furnace 3 for heating the airtight sample container 1 from the periphery and bottom is arranged so as to be movable up and down, surrounding the sample container 1. The temperature can then be set and maintained at any temperature up to room temperature, and by moving this downward, the airtight material container 1 can be detached from the support section 2.

Further, the airtight sample container 1 is electrically connected to the container 1.
is provided with dry gas and solvent introduction means 4 capable of selectively introducing dry gas or a dehydrated solvent.

The drying gas and solvent introducing means 4 includes a drying gas injection pipe 4a connected to a gas source 7 such as N2 through a dryer 6 and a flow meter 6, and a drying gas injection pipe 4a connected to a gas source 7 such as N2 through a dryer 6 and a flow meter 6, and a solvent (at) filled with a dehydrating agent. The solvent injection tubes 4b connected to the column 8, which also serves as a column, are inserted into the hollow supporting part 2 and arranged to be electrically connected to the airtight sample container 1, respectively, and the container 1 is injected with dry gas and dehydration. Alternatively, the dry gas injection pipe 4a and the solvent injection pipe 4b may be provided to selectively inject the solvent.
Illustrated example of airtightness sample l.

It is formed by connecting an introduction pipe 4C which is conductively arranged to reach the bottom of the container 1 with a four-way cock 4d interposed therebetween.

If the drying gas and solvent introduction means 4 are formed as the latter described above, the drying gas and solvent can be injected and shut off into the airtight sample container 1, respectively.
- They can be selectively injected into the section length by operating the individual cocks 4d, and the introduction pipe 4C and the Mizoyama pipe 9 form a double pipe 10, and the base of the double pipe 100 is connected to the supporting part 2. It is convenient to maintain continuity between each injection tube and the airtight sample container 1.

Further, the solvent injection pipe 4b is connected to the column 8 via a joint 8a, and a discharge pipe 11 is provided in the four-way cock 4d.

That is, the four-way cock 4d has four ports, each of which is connected to the dry gas injection pipe 4a, the solvent injection pipe 4b, and the introduction pipe 4.
C, the discharge pipe 11 is connected, and the plug 4d of the cock 4d
As clearly shown by IBI in FIG. 2, ' is provided with a through hole 4d# that conducts in the perpendicular direction, and only two adjacent channels are selectively connected.

Therefore, the plug 4d' connects the flow path of the dry gas injection tube 4a and the introduction tube 4c as shown in FIG. Although not shown in the drawings, the dry gas injection tube 4a and the discharge tube 11 and the solvent injection tube 4b and the discharge tube 11 are rotated in order to conduct each other. It is used to selectively introduce a drying gas and a solvent into the sample container 1, respectively, and to discharge only the drying gas or solvent from the discharge tube 11.

Further, the groove tube 9 has a heating coating 9a on its inner wall to prevent condensation of groove particles, and is connected to a titration cell 1 of a Karl Fischer coulometric titration device (not shown) via a joint 12.
It is connected to the foam tube 14 inserted into the tube 3.

Further, the dryer @6 consists of one silica gel column and two phosphorus pentoxide groups.

The column 8 is filled with a dehydrating agent X such as molecular sieve or alumina.
It serves both for holding and dehydrating the solvent 3 such as toluene and xylene, and the upper part is connected to the outside air via a dryer 15, with a distance of 1 m in the middle.
There is a series of solvent scales 16 that are graduated for each l.
The head of the column 8, which is shaped like a letter, allows the amount of solvent a read by the meter 16 to flow into the airtight sample container 1 by operating the cock 4d.

Therefore, in order to perform the moisture measurement of the first invention using the above-mentioned measuring device, the heating furnace 3 must be set to a predetermined temperature (80 to 1
40°C), and the drying gas was kept at a predetermined flow rate (0.3t/
Assuming that the required amount (within 5 mt) of solvent a is prepared in the column 8, first, the heating furnace 3 is lowered, and about 5 ml of the solvent is collected by the drying residue and the solvent introducing means 4.
After injecting into the airtight sample container 1, drying gas is injected.

Next, several grams of the sample are injected from the sample injection port 1a using a syringe, and the heating furnace 3 is fixed at the top.

(Thus, since the airtight sample container 1 is heated from the outside, when the temperature of the container 1 eventually reaches the azeotropic point, the water in the sample evaporates along with the solvent, is carried by the drying gas, and flows into the groove. It passes through the mountain pipe 9 and reaches the titration cell 13.

Next, when the Karl Fischer coulometric titrator (not shown) is started, measurement begins.

When most of the water contained in the sample has been distilled out, the operation of the titration device is automatically stopped, and the total amount distilled out is displayed in μg on a meter (not shown).

For example, select toluene (azeotropic temperature 84°C when water content is 196%) as the solvent, and set the temperature of the heating furnace 3 to 120°C.
At this time, the temperature of the liquid in the airtight sample container 1 is set to 4.
As shown in the figure, the temperature is about 1100C, so when performing the above measurement using 5 m/a solvent for 2 to 3 g of lubricating oil, the water content can be measured in 5 to 10 minutes (water content due to the nature of the sample). (depending on) end.

Therefore, the measurement time is shortened compared to 10 to 30 minutes for the conventional vaporization method and a little less than 1 hour for the distillation method, and the amount of solvent used in the distillation method can be much smaller.

Figure 3 compares the progress of water elution when the same sample is heated at the same temperature using the device of this invention and the conventional vaporization method (just expelling it with dry gas). This shows that the addition of a small amount of solvent accelerates the sliding rate of water.

Figure 4 shows the relationship between the temperature setting of the heating furnace and the internal liquid temperature. From the figure, if you select an appropriate heating temperature depending on the solvent and sample, you can prevent the liquid temperature from rising excessively and thereby reduce the influence of interfering substances. You can see that it can be kept to a minimum.

〔Effect of the invention〕

Since the method according to the first invention of the present application is configured as described above, it is possible to selectively distill only moisture by selecting an appropriate solvent and setting temperature, and therefore, it is possible to accurately distill even trace amounts of moisture. Not only can the measurement be performed using a much smaller amount of solvent than in the conventional method, but also in a short period of time, and the flow rate of the drying gas can be reduced to completely eliminate the moisture content.

In addition, when using the powder method, it can be applied not only to inorganic compounds but also to measuring the moisture content of organic acids, amines, aldehydes, ketones, etc. that cannot be titrated directly by the Karl Fischer method due to side reactions with Karl Fischer reagents. can.

Furthermore, since the measuring device according to the second invention of the present application is also configured as described above, it is possible to supply the sample in an airtight state into the airtight sample container, and also to selectively operate the drying gas and solvent introduction means. This makes it easy to mix a solvent into the sample or supply drying gas at the appropriate time.Moreover, since the droplet gas containing moisture from the sample is sent into the titration cell via a heat-insulating reservoir pipe, the moisture can be removed. are all measured in the same cell, and the method according to No. 15 @ Ming can be efficiently implemented.

[Brief explanation of drawings]

FIG. 1 is an explanatory front view, partially cut away, showing an embodiment of an apparatus for measuring moisture contained in lubricating oil, etc., according to the second invention of the present application;
+AI in Figure 2, (Bl is a cross-sectional view showing each operating state of the cock of the drying gas and solvent introduction means in the same device, and Figure 3 is the water elution at the same heating temperature by the same device and the vertical example. A comparison diagram of the progress, and Fig. 4 is an explanatory diagram of the relationship between the heating temperature of the heating furnace and the temporal change in the liquid temperature in the airtight sample container in the same apparatus.a...Solvent 1... Airtight sample container 1a...Sample injection port 3/1 Fist heating furnace 4...Dry gas and solvent introduction means 4a...Dry gas injection tube 4b...Solvent injection tube 4d... ... Cook 9 ... Sliding pipe that can be kept warm 13 lives ... Fist e Dripsei Cell Agent Patent Attorney Yoshio Saito -1'5-

Claims (3)

[Claims] (1) Make an azeotrope with a small amount of sample such as lubricating oil and water,
and a small amount of dehydrated solvent that dissolves the above sample in an airtight container, and while heating this to around its azeotropic point, a dry gas such as N_2 is vented into the airtight container. As a result, water in the sample is distilled out together with the solvent, and this distilled gas is introduced into a suitable cell using the dry gas as a carrier, where it is measured by the Karl-Fuscher method. A method for measuring the moisture content of lubricating oil, etc. (2) Equipped with an airtight sample container having a sample injection port and a heating source that heats the airtight sample container to a set temperature from the outside, and in which a dry gas such as N_2 is added to the airtight sample container. A drying gas and solvent introduction means that can selectively supply either dehydrated solvent or dehydrated solvent are connected to each other, and the sample container and the calibration cell of the Karl Fischer coulometric titration device are connected to a reservoir that can be kept warm. A device for measuring moisture contained in lubricating oil, etc., characterized in that it is communicated through an exit pipe. (3) A patent claim in which the drying gas and solvent introduction means is configured by connecting the drying gas injection tube and the solvent injection tube to an introduction tube connected to the airtight sample container via a switching cock. A device for measuring moisture contained in lubricating oil, etc. according to item 2.