JPS6022266B2 - Moisture measuring device in vacuum drying process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for vacuum drying the inside of a container that requires airtightness, such as an accumulator, receiver, or heat exchanger of a refrigerator.
The present invention relates to a moisture measuring device for measuring whether or not there is moisture in the container and the degree of moisture.

If foreign gas or moisture remains inside the soot system of the refrigerator, it is undesirable as it will reduce the refrigeration capacity. Therefore, connect the inside of the cold soot system to a vacuum pump or other device. By lowering the vacuum pressure to a predetermined value, the gas is discharged and dried at the same time.

However, in the past, there was no equipment that could easily test the moisture content during the vacuum drying process, and since it was not possible to test the moisture content by performing the extraction operation and mochi process, empirically, moisture was extracted by extending the extraction operation. It was treated as such.

Needless to say, such an unscientific operation process is inefficient as it increases the vacuum drying time.Also, since a portion of the product was sampled and moisture content was measured separately for quality control, vacuum drying Another problem was that the reliability of dryness tests was low.

In order to cope with the current situation, the present invention has been made with an attempt to provide a new moisture measuring device that can easily and reliably perform a moisture test in parallel with vacuum drying treatment. In the tube connecting the drying container and the air outlet of the air equipment,
A first on-off valve, a detection container, and a second on-off valve are interposed in series, and in relation to the detection container, a measuring device for measuring the degree of vacuum in the container and a Fuki point for measuring the Fuki point temperature. A pipe having a third on-off valve, a dryer, an air pump, and a fourth on-off valve connected in series is connected between the inlet and outlet of the detection container, and a fifth on-off valve is attached. The container to be dried can be dried by branching and connecting an air supply pipe having a It is characterized in that the degree of vacuum and moisture can be measured as the total pressure of gas exhausted and the partial pressure of water vapor on the detection container side.

The invention will be explained in more detail below on the basis of the examples of the accompanying drawings, in which: FIG.

In the figure, reference numeral 1 denotes a container to be dried, such as an evaporator or a receiver, which is connected to an air purifier 2 such as a vacuum pump through an air pipe 3 in which a sixth on-off valve 9 is interposed.

In connection with the above-mentioned Yuzu trachea 3, there is provided an example of the device of the present invention which is surrounded by a two-dot chain line frame, and this device includes a first on-off valve 10, a detection container 4, a second on-off valve 11 a pipe line 15 connected in series between the inlet and outlet of the sixth on-off valve 9;
, a measuring device 5 that can measure the degree of vacuum in the detection container 4 with a sensor 18 , a Fujipoint meter 6 that can also measure the temperature at the bottom point with a sensor 19 , and a third on-off valve Tatami 2 , The dryer 7 has an air pump 8 and a fourth on-off valve 13 connected in series, and a pipeline 16 connected between the inlet and outlet of the detection container 4, a fifth on-off valve 14, and a dryer 20 with an on-off valve 21. and an air supply pipe group 7 connected in series and branched to the pipe line 16.

The detection container 4 is an airtight container with a volume of 4 mm, which is much smaller than that of the container 1 to be dried.
As the on-off valve 14, a solenoid valve is used for convenience of control.

Further, as the measuring device 5, a vacuum switch or a vacuum gauge is used as needed.

The above-mentioned device for slow construction includes a first preparation means for maintaining the detection container 4 and the pipe line 16 at atmospheric pressure, a second preparation means for drying the air inside the detection container 4, and the inside of the container to be dried 1 and the detection container. It is possible to measure the moisture content in the container to be dried 1 by sequentially carrying out the three means of measuring the degree of vacuum and the temperature in the detection container 4 during the process of extracting the air in the container 4. The method of measurement will be described later, but to first summarize the principle of moisture measurement, let's assume that the inside of the container before vacuum drying was in the atmosphere with 20 contact points.

First, when the inside is depressurized using the extraction device 2, which is a vacuum pump, if there is only gas and no moisture in the container from the beginning, the water vapor partial pressure will change at the same rate as the total pressure, and the dew point temperature will change at the same rate as the total pressure. The dew point (D, P) decreases along the curve of 20 qo in Figure 2.

However, if moisture is present in addition to gas in the container, as the internal pressure is reduced, the evaporation of that moisture is accelerated, and the ratio of water vapor partial pressure to total pressure increases.
Therefore, the dew point temperature does not decrease along the above-mentioned curve, but instead approaches the curve of saturated water vapor pressure. By using this principle and measuring the dew point under a constant vacuum, it is possible to determine the presence or absence of moisture.

For example, if the quality standard for the moisture in the container before vacuum drying is less than the moisture in the air of 20 qo, and the dew point is measured when the vacuum level is 1 Hg after drying, then if the product passes the quality standards. , D, P decreases along the line of 20°C and shows -152 to -153 Ma0. On the other hand, if there is abnormal moisture inside, the dew point shows a maximum of -17 to -18 Qo (saturated water vapor pressure). Therefore, it is possible to know the degree of moisture by measuring the degree of vacuum and the crab point.

Next, the mode of measurement using the above device will be explained.

{i) First preparation means, third on-off valve 12, fourth on-off valve 13
``Open the fifth on-off valve 4 and on-off valve 28, and close the other on-off valves 9, 10, 11'.

By opening the air supply pipe 17, the detection container 4 is opened to the atmosphere, and the detection container 4 is filled with air that has passed through the dryers 20 and 7.

On the other hand, the container to be dried 1 is disconnected from both the drying chamber 2 and the detection container motherboard.

‘.

'Second preparation means, third on-off valve 12 and fourth on-off valve 13
, and close the other on-off valves 9, 0, 1, 14, and 2, and operate the air pump 8.

As a result of forming a sealed circuit of the air pump 8, the dryer 7t and the detection container 4, moisture is built up in the dryer 7 and the air inside the detection container 4 is dried.

Then, the air pump 8
After operating the air pump 8, the air pump 8 is stopped and both the on-off valves 12 and 13 are closed.

1. Measuring means (also serves as the citrus process), first on-off valve 10
And open the second on-off valve 11 and open each of the other on-off valves 9, turtle 2?
Colors 3, 14, and 21 are closed.

The bleed device 2 is activated before and after this operation.

In this way, the container i to be dried and the detection container 4 are connected in series and are passed through the citron air opening of the citrus air supply counterfeit 2, so that both containers 1
The air within 44 is extracted at the same time.

This continuous bleed air rotation is controlled so that the measuring device 5 maintains an indication of a predetermined degree of vacuum. After the degree of vacuum inside both containers 6 and 4 has fallen to a predetermined value, wait for the time required for the fog point meter 6 to respond, and then measure the degree of vacuum inside the detection container 4 and the fog point. The presence and extent of moisture in the drying container 1 can be determined using the detection container 4 under the same conditions.

A single measurement can be completed by performing the following three steps, but each time the container 1 to be dried is connected to the aeration device 2 and air is extracted, the moisture content can be measured easily and quickly.

In addition, in the above-mentioned three means, the second preparation means {o) may be followed by the measuring means, and the second preparation means {o) may be followed by the measuring means.In that case, the sixth opening and closing step may be continued. When the valve 9 and the second on-off valve 11 are opened and the other on-off valves 10, necks 2, 13, 14, and 21 are closed, and the citrus aeration device 2 is activated, both the containers 1 and 4 are individually filled with citrus aoi. Fake 2
After the selection process, Yuki is performed.

By adopting this method, for example, when there is a considerable amount of moisture in the container to be dried,
It is possible to extract water directly and quickly by the aeration device 2, and by circulating the water into the detection container 4, there is an advantage that an adverse effect on the measurement process can be eliminated.

As is clear from the detailed description above, the apparatus of the present invention has a first on-off valve 18 and a detection container 4 in a conduit 15 connecting the container 1 to be dried to be vacuum dried and the bleed port of the bleed bag hawk 2. A second on-off valve 1 is interposed in series, and a measuring device 5 for measuring the degree of vacuum in the container 4 and a dew point meter 6 for measuring the cross point temperature are attached in association with the detection container 4. On the other hand, a conduit 16 having a third on-off valve 2, a dryer 7, an air pump 8, and a fourth on-off valve 13 connected in series is connected between the inlet and outlet of the detection container 4. 5 Opening/closing valve] The air supply pipe neck 7 having a valve 4 is branched and connected to the pipe line 161, and the structure is extremely simple and can be formed compactly. At this time, the third on-off valve 12, the fourth on-off valve 13, and the fifth on-off valve 14 are opened, and the other on-off valves IQ and Fuki are closed to maintain the detection container 4 and the pipeline 16 at atmospheric pressure. The first preparation means opens the third on-off valve 12 and the fourth on-off valve 13, closes the other on-off valves 8 and 4, and operates the air pump 8, so that the dew point meter 6 reaches a predetermined low dew point. The second preparation means, which dries the air in the detection container 4 until the opening of the first on-off valve Q and the second on-off valve 1, and the other on-off valves 12
, 3 and 14 are closed and the container to be dried and the detection container 4 are air-filled, and the vacuum level and the hair point inside the detection container 4 are measured. It is possible to measure moisture by sequentially performing the following steps, and the operation is extremely simple and can be done in a short time as all you have to do is turn on and off the five on-off valves 18 to 4 and the air pump 8. Not only can measurements be performed, but the measurement accuracy is high and reliability is high, and there is no need to take an unnecessarily long vacuum drying operation time, thereby improving drying efficiency.

Furthermore, the present invention allows moisture content to be easily and quickly measured in connection with this vacuum drying process each time the container 1 to be dried is connected to the drying device 3. It also has excellent effects that contribute to improvement.

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram according to an example of the apparatus of the present invention, and FIG. 2 is a diagram of temperature change at a double point with respect to pressure for explaining the measurement principle according to the present invention. Tortoise...Container to be dried, 2...Yuzu air pipe 3...Yuzu trachea, 4...Detection container, 5...Measuring device, 6
...Iso point measurement 7...Dryer, 8...Air pump
Wealth ■...First on-off valve, 1 corner...Second on-off valve, 12.
...Third on-off valve, turtle 3...Fourth on-off valve, wealth 4...
5th on-off valve, 15...pipeline, 16...pipeline, turtle 7.
...Air supply pipe. Figure 1 Figure 2

Claims (1)

[Claims] 1 A first on-off valve 10, a detection container 4, and a second on-off valve 11 are interposed in series in a conduit 15 that connects a container to be dried 1 that performs vacuum drying inside the container and an air extraction port of an air extraction device 2. A measuring device 5 for measuring the degree of vacuum in the container 4 and a dew point meter 6 for measuring the dew point temperature are attached in association with the detection container 4, while a third on-off valve 12 and a dryer 7 are provided. A conduit 16 having an air pump 8 and a fourth on-off valve 13 connected in series is connected between the inlet and outlet of the detection container 4, and an air supply pipe 17 having a fifth on-off valve 14 is connected to the conduit. 16 to open the third on-off valve 12, fourth on-off valve 13, and fifth on-off valve 14, and close the other on-off valves 10 and 11 to open the detection container 4 and the pipeline 16. By opening the first preparatory means, the third on-off valve 12 and the fourth on-off valve 13 for maintaining atmospheric pressure, and closing the other on-off valves 10, 11, 14 and operating the air pump 8, the dew point meter 6 is A second preparation means for drying the air in the detection container 4 until it reaches a predetermined low dew point, the first on-off valve 10 and the second on-off valve 11 are opened, and the other on-off valves 12, 13, and 14 are closed to dry the air. While bleeding air with the container 1 and the detection container 4 in communication with each other, the measuring means for measuring the degree of vacuum and dew point in the detection container 4 is sequentially performed,
A moisture measuring device in a vacuum drying process, characterized in that the degree of moisture in a container to be dried 1 is measured from the total pressure of the gas to be evacuated and the partial pressure of water vapor.