JPH08192021A - Air drying device - Google Patents

Abstract

PURPOSE: To prevent occurrence of accident previously by always monitoring a reproduction state of an adsorbent and promptly catching the state in which the water content is abnormally remaining in the absorbent. CONSTITUTION: Temperature sensors 30a, 30b are arranged at the position equivalent to the outlet side of reproduction air (the inlet side of air to be treated at an air drying time) at the reproduction time of adsorbers 7a, 7b in an air drier, and besides alarm setting devices 31a, 31b for receiving a signal from the temp. sensors 30a, 30b and sounding an alarm are connected with the temp. sensors 30a, 30b, and then the state in which the water content is abnormally remaining in the absorbent 6 can be promptly caught. Since the temp. at the position shows a clearly different curve depending on whether the water content of the absorbent 6 is normal or abnormal, the abnormality of the absorbent 6 can be promptly caught by monitoring the temp. and the situation can be accommodated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for drying air, and more particularly to a device for drying an air used as a material for drying an ozone generator.

[0002]

2. Description of the Related Art For example, in an ozone generator, air, which is a raw material for ozone, is dried at a low temperature and sent to an ozone generator. Therefore, in general, the ozone generator is often incorporated with an air dryer.

A conventional configuration of such an air dryer is shown in FIG.
Shown in In FIG. 4, reference numeral 1 is an air supply device for supplying raw material air, and this air supply device 1 is configured by arranging a blower 2, a cooler 3 and a cooling dryer 4 in series. An outflow pipe 5 is connected to the cooling type dryer 4, and a pair of adsorbers 7a and 7b filled with an adsorbent 6 (eg silica gel, alumina gel) are connected to the outflow pipe 5.
The pipes 11a and 11b and the switching valve 8a are connected to each other. Further, a pair of lower limit temperature sensors 9a and 9b and a pair of upper limit temperature sensors 10a and 10b are arranged in the adsorbers 7a and 7b, respectively, and detect the temperature (air temperature) of the adsorbent 6, respectively. Is ready to go.

Further, a switching valve 8b is installed on the outlet side of both adsorbers 7a and 7b. The air passing through the switching valve 8b reaches the ozone generator 15 through the supply pipe 16. A return pipe 17 is connected to the supply pipe 16, and the return pipe 17 includes an opening / closing valve 18 and a heater 1.
9 are provided. A branch pipe 20 and a dew point meter 21 are installed on the supply pipe 16.

In the cooler 3 and the cooling dryer 4, drain pipes 3a, 4a and drain dischargers 3b, 4 for discharging condensed water produced when the compressed air is cooled.
b are arranged respectively.

This device has a switching valve 8a,
8b is switched to the direction of the solid line shown in FIG. 4, and the opening / closing valve 18 is open. First, the high-temperature and high-humidity compressed air supplied from the blower 2 reaches about 4 ° C. by the cooler 3 and the cooling dryer 4, removes the condensed water into the drain pipes 3a, 4a, and then passes through the switching valve 8a. And is introduced into the adsorber 7a. The introduced air is 1 in the adsorber 7a.
It becomes ultra dry air with a dew point of -60 ° C or lower at about 0 ° C. The air discharged from the adsorber 7a passes through one of the switching valves 8b and the supply pipe 1
6, and is further sent to the ozone generator 15.

At this time, a part of the air is pressure-fed from the supply pipe 16 to the heater 19 through the on-off valve 18, heated there, and then introduced into the adsorber 7b from the other side of the switching valve 8b. The high temperature dry air introduced into the adsorber 7b removes the adsorbent 6 by about 2
The adsorbent is regenerated by heating it to about 00 ° C. to dry it at a high temperature and then discharged from the switching valve 8a to the outside of the machine.

In this way, the adsorbent of one of the adsorbers 7a dehumidifies the air to produce ultra-dry air, while the adsorbent of the other adsorber 7b is regenerated with hot air. .

A pair of upper temperature sensors 9a and 9b attached to both the adsorbers 7a and 7b detect the high temperature dry air so as not to fall below a set value and control the heater 19. . In addition, the lower temperature sensors 10a and 10b of the adsorbers 7a and 7b have a temperature of 180 ° C.
The operation of the heater 19 is stopped when the temperature rises above the temperature.

The switching valve 8a is switched by a timer (not shown) after a fixed time, and the flow of air is reversed. This causes the adsorber 7a to pause and enter a regeneration cycle, which operates the adsorber 7b to produce ultra-dry air. In this way, the super dry air is converted into ozone generator 15
Will be continuously supplied to. Reference numeral 21 is a dew point meter, and a small amount of dry air is introduced from the supply pipe 16 to measure the air dew point.

[0011]

The problem with the above-mentioned air dryer is that the dew point of the produced dry air is-
The problem is that the temperature rises above 60 ° C. The possible causes are as follows.

(1) Reduction of cooling capacity due to increase of cooling water temperature of the cooler 3 (2) Reduction of cooling capacity due to dirt of the cooler 3 (3) Poor drain water discharge due to clogging of the drain discharger 3b of the cooler 3 (4) Leakage of the cooling water of the cooler 3 to the compressed air side (5) The capacity of the cooling / drying machine 4 is reduced due to the increased load due to the above (1) to (3). (7) Drain water discharge failure due to clogging of the drain discharger 4b of the cooling / drying machine 4 (8) Insufficient processing of the cooling machine 3 and the cooling / drying machine 4 due to a decrease in discharge pressure of the blower 2

Due to these causes, the adsorber 7a sucks in air containing water at a level higher than the treatment capacity, and the water in the adsorber 7a can be completely removed and eliminated in the set cycle of the heating regeneration action. Disappear. While this adsorption regeneration is repeated, the water supply capacity of the adsorbent gradually decreases, and the dew point of the air flowing out from the adsorber 7a (or 7b) rises.

The state will be described with reference to FIGS. FIG. 5 is a diagram showing a state in which one cycle of moisture adsorption and regeneration of the adsorber is 16 hours. The horizontal axis represents time (hour), and the vertical axis represents the amount of water remaining in the adsorbent (%) and the temperature in the adsorber (° C).
As shown in the figure, a constant flow rate of air passes through the adsorber from 8 hours after the start, and the amount of water proportional to time is accumulated in the adsorber. During this time, the temperature sensor 9a in the adsorber,
The detected temperature of 10a is about 10 ° C., which is the temperature obtained by adding the heat of adsorption generated when the adsorbent adsorbs moisture to the temperature of the air flowing in from the cooling dryer 4 of about 5 ° C. This temperature is maintained during the adsorption time. In addition, the amount of water accumulated in the adsorber 7a in these 8 hours is 100%.

After 8 hours, the adsorber is switched from adsorption to regeneration and hot air from the heater 19 flows through the adsorber. Along with that, the indicated value of the temperature sensor 9a rises and is controlled at about 200 ° C. The indicated value of the temperature sensor 10a rises later than the temperature sensor 9a and rises to 180 ° C.
When it reaches a certain level, the heater 19 is turned off. After that, the regeneration air rapidly becomes cold. Since the low temperature regeneration air continues to flow, the indicated values of the temperature sensors 9a and 10a gradually decrease, and at 16 hours, the temperature is almost the same as that at the start of adsorption. The residual water content in the adsorber decreases with the passage of time for regeneration, and approximately 14 hours have passed since the start (6
The residual water content becomes 0% at the time point). It should be noted that, in the above, the measurement of the water content is a result of sampling and analyzing the gas at regular intervals because there is no method for continuously and timely measuring the water content.

The above is the action diagram in the state where it normally operates, but the action diagram when some trouble occurs as described above is as shown in FIG. In FIG. 6, the residual water content curve under normal conditions is indicated by a, and the residual water content curve under abnormal conditions is indicated by b. Regarding the temperature curve, the temperature curve of the temperature sensor 10a in the normal state is shown by 10a-a, and that in the abnormal state is shown by 10a-b. The temperature indication value of the temperature sensor 9a was omitted because it is a change that is not abnormal due to normal abnormalities.

As shown in FIG. 6, in the abnormal condition, the temperature instruction of the temperature sensor has a time lag in the rising curve as compared with the normal condition, but there is no big difference. However, in the case of an abnormal state, the water content does not become 0% at the end of one cycle (16 hours) (X in the figure) and is carried over to the next cycle. Then, in the next cycle, the residual water content is also added, and by repeating this, the water content increases more and more. As a result, the indicated dew point of the dew point meter 21 rises,
The temperature becomes −60 ° C. or higher (the presence or absence of residual water cannot be determined from the temperature change of the temperature sensor 10a).

When air having a dew point of −60 ° C. or higher is flown through the ozone generator for a long time, 1) the ozone yield is lowered and the running cost is increased. Further, 2) NOx and water are combined in the ozone generator to generate an acid, and the acid promotes deterioration of the material in the ozone generator. In order to prevent these, when the dew point rises, it is necessary to temporarily stop the air dryer to remove the water content of the adsorbent. This restoration work requires a period of one week or more and a great deal of labor.

The present invention has been made in consideration of the above problems, and in an air drying apparatus, the regeneration state of the adsorbent is constantly controlled to prevent the dew point of the dry air from rising, and there is no need for recovery work. The purpose is to maintain driving conditions.

[0020]

That is, according to the present invention, the position corresponding to the outlet side of the regenerating air during regeneration of the adsorber in the air dryer (the treated air inlet side during air drying).
A temperature sensor is provided in the temperature sensor, and an alarm setting device that receives a signal from the temperature sensor and issues an alarm is connected to the temperature sensor so that an abnormality during operation can be constantly monitored.

[0021]

In the air dryer of the present invention, since the temperature sensor is provided at the position corresponding to the outlet side of the regeneration air during regeneration of the adsorber (the inlet side of the air to be treated during air drying), the adsorption cycle Then, the temperature of the air to be dried can be continuously measured, and the temperature of the regenerated air can be continuously measured in the regeneration cycle. As shown in FIG. 3, during normal regeneration work, this temperature change changes with time, and the water content in the adsorber rapidly rises from the time when it reaches 0% to 100 ° C.
The above peaks are obtained (see the curve 30a-a in FIG. 3).
On the other hand, when the temperature is abnormal, the temperature rise is slight and stays below 50 ° C. (see the curve 30a-b in FIG. 3). Therefore, by comparing the temperature curve measured in an arbitrary regeneration process with the temperature curve in the normal condition (water content 0%), and setting an alarm to be issued if an abnormality is recognized as a result, air drying is always continuously performed. It is possible to catch abnormalities in the device.

[0022]

An embodiment of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram for explaining an embodiment of the present invention. In this figure, the configuration before the switching valve 8a and the configuration after the switching valve 8b are the same as the conventional one (see FIG. 4), and are therefore omitted. In FIG. 1, 30a, 30
b is a temperature sensor provided in the pipes 11a and 11b connecting between the adsorbers 7a and 7b and the switching valve 8a, and 31a and 31b are temperature sensors 30a and 3b, respectively.
It is an alarm setting device wired to 0b.

Next, the operation of drying air with this apparatus will be described. Similar to the conventional device, the air passes through the blower 2, the cooler 3, and the cooling type dryer 4 (see FIG. 4) and then the switching valve 8a.
Reach The air that has passed through the solid line of the switching valve 8a is
The temperature is measured by the temperature sensor 30a through a, and is recorded as a relation between time and temperature by the alarm setter 31a. Next, the air passes through the adsorber 7a to adsorb moisture by the adsorbent 6, becomes dry air, flows out through the solid line of the switching valve 8b, and is supplied to the ozone generator or the like. The same thing is carried out in the adsorber 7b with a shift of 8 hours.

After 8 hours, the switching valves 8a and 8b are switched, and the regenerated air passes through the dotted line of the switching valve 8b and the adsorber 7a.
The temperature of the regenerated air that has entered and has passed through the adsorber 7a is measured by the temperature sensor 30a in the same manner as described above, and is discharged through the dotted line of the switching valve 8a.

FIG. 3 shows the relationship between the elapsed time, the temperature, and the residual water content at this time. In FIG. 3, the residual water content curve under normal conditions in FIG. 6 is indicated by a, the residual water content curve under abnormal conditions is indicated by b, and the temperature curve of the normal temperature sensor 30a is indicated by 3
0a-a, the temperature curve of the temperature sensor 30a at the time of abnormality is set to 3
It is indicated by 0a-b.

As shown in FIG. 3, in the adsorption process,
There is no change in temperature during normal and abnormal conditions, but in the regeneration process, the temperature rises as the residual water decreases in the normal state (30a-a), and when the residual water reaches 0, the temperature changes. It shows a peak and reaches 100 ° C or higher, whereas the temperature does not rise so much at the time of abnormality (30a-
B). This is because water remains in the case of abnormality even after the lapse of 14 hours when the remaining water amount becomes 0 in the normal case. Even after 16 hours from the completion of the regeneration step, there is residual water, and the peak is no higher than 50 ° C.

This normal reproduction pattern is used as the alarm setting device 3
It is recorded in advance in 1a and compared with an arbitrary regeneration temperature pattern during operation. When the regeneration temperature decreases by 30 to 50% of the normal temperature peak throughout the process period, the alarm setter 31a issues an alarm. Be sure to emit.
Measures such as stopping the system components are taken according to the output signal.

As described above, the temperature indicated by the temperature sensor on the outlet side of the adsorber during regeneration sensitively reflects the amount of residual water during regeneration of the adsorber. Therefore, a temperature sensor and an alarm setting device are installed at this position. By doing so, it is possible to catch abnormalities in the air dryer quickly and prevent serious accidents.

(Embodiment 2) In this embodiment, the switching valve 8a
A pipe 12 is provided on the discharge side of the, and a temperature sensor 30 and an alarm setter 31 are provided on the pipe 12. This is because there is almost no temperature change in the adsorbers 7a and 7b at the time of adsorption, so that the temperature is not measured at the time of adsorption and the temperature is measured only at the time of regeneration to try to catch the abnormality as in the above embodiment. According to this method, it is not necessary to use two sets of temperature sensors and alarm setting devices as in the above-mentioned embodiment, and one set can function for both adsorbers 7a and 7b.

[0030]

As described above, the air drying apparatus of the present invention monitors the temperature at the outlet side of the adsorber during regeneration so as to catch the state where water remains abnormally in the adsorber during regeneration. Therefore, a serious accident can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating another embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the present invention, showing the relationship between the residual water content of the adsorber and the temperature measured by a temperature sensor.

FIG. 4 is a configuration diagram of a conventional air dryer.

FIG. 5 is a diagram showing the relationship between the residual water content of the adsorber and the temperature measured by a temperature sensor when the conventional air dryer is operating normally.

FIG. 6 is a diagram showing the relationship between the residual water content of the adsorber and the temperature measured by a temperature sensor when the conventional air dryer is in a normal state and in an abnormal state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air supply device, 2 ... Blower, 3 ... Cooler, 4 ... Cooling dryer, 6 ... Adsorbent, 7a, 7b ... Adsorber, 8a, 8
b ... switching valve, 9a, 9b ... temperature sensor, 10a, 10
b ... Temperature sensor, 15 ... Ozone generator, 19 ... Heater, 30, 30a, 30b ... Temperature sensor, 31, 31
a, 31b ... Alarm setting device.

Claims (3)

[Claims] 1. An air drying apparatus having a pair of adsorbers, wherein the pair of adsorbers are alternately operated to dry air and regenerate the adsorbers, wherein regeneration air is used when the adsorbers are regenerated. An air dryer, wherein a temperature sensor is installed at a position corresponding to the outlet side of the device, and an alarm setting device that receives a signal from the temperature sensor is installed in connection with the temperature sensor. 2. The air drying device according to claim 1, wherein the temperature sensor is installed in each of the regeneration air outlet side pipes of each adsorber. 3. The air drying apparatus according to claim 1, wherein the temperature sensor is installed at a regeneration air outlet of a switching valve on the regeneration air outlet side of each adsorber.