JP3483797B2 - Method and apparatus for dehumidifying compressed gas - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of dehumidifying a compressed gas in which a moist compressed gas is adsorbed and dehumidified using an adsorbent and then dried, and particularly to prevent early deterioration of the adsorbent. About energy-saving driving.

[0002]

2. Description of the Related Art In a conventional dehumidifying apparatus, two dry adsorption air is continuously supplied, and therefore two adsorption cylinders are prepared in which a container is filled with an adsorbent such as activated alumina, silica gel, synthetic zeolite or lithium chloride. .

Wet compressed air is introduced into one of the adsorption cylinders to be adsorbed and dried, and supplied to a predetermined supply destination. At the same time, a part of the obtained dry air is introduced to the other adsorption cylinder, and moisture is desorbed from the adsorbent whose hygroscopic capacity has decreased by absorbing moisture in the previous stage, and this moisture is further purged from the adsorption cylinder. Eggplant In this regeneration step, about 20% of the obtained dry air was released to the atmosphere.

The drying of the compressed air in one of the adsorption cylinders and the regeneration of the adsorbent in the other adsorption cylinder are simultaneously performed in parallel, and a switching valve provided between the adsorption cylinders is operated after a predetermined time has elapsed. Switch to supply dry air continuously.

By the way, since the dehumidifier is designed on the basis of the most harsh summer conditions in which the ambient temperature and the intake air temperature rise, the dehumidifier is adsorbed, for example, when it is used in winter or when the load on the supply destination is reduced. It is desirable to reduce the adsorption action of the agent to achieve this long life.

Conventionally, energy saving operation as shown in FIG. 9 has been performed. That is, the switching operation of the switching valve is stopped, and all the purge valves connected to the adsorption cylinders are closed. For example, while the compressed air that has been wetted is guided only to the B cylinder to continue the drying for adsorption and dehumidification, the regeneration of both the A and B cylinders is stopped.

[0007]

In the energy saving operation, when the switching operation of the switching valve is stopped and all the purge valves connected to the adsorption cylinder are closed, the amount of dry air discharged by the purge is increased. Decreases. However, the energy saving operation described above may be continued for a long time depending on conditions. During this time, the adsorbent in one of the adsorption cylinders only performs the adsorption action, and the adsorbent in the other adsorption cylinder does not have any action.

Therefore, in the state of returning to the standard operation, the balance between the amount of adsorbed water of the adsorbent in the adsorption column that continues dehumidification and drying and the amount of adsorbed water of the adsorbent in the other adsorption column having no effect is poor. Become. Actually, the dew point temperature of the dry air supplied from the side where the dehumidifying and drying is continued becomes higher than the dew point temperature of the dry air supplied from the other side.

After all, the adsorbent on the side that has continued the adsorption action for a long time deteriorates earlier than the adsorbent on the other side, and it becomes necessary to replace it with a new adsorbent. If one of the adsorbents deteriorates, both of them are generally replaced, and the other adsorbent becomes useless replacement, which adversely affects the running cost.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to reduce the discharge amount of dry air by purging to a small amount in both so-called energy-saving operation, while maintaining both adsorption cylinders. The deterioration of the adsorbent inside is promoted evenly, the fluctuation of the dew point temperature between each adsorption cylinder when returning to the standard operation is suppressed, and the adsorbent replacement timing is eliminated at the same time to eliminate wasteful replacement and running. An object of the present invention is to provide a dehumidification method for compressed gas and a device therefor, which contributes to cost reduction.

[0011]

In order to satisfy the above object, the method of dehumidifying a compressed gas of the present invention introduces a damp compressed gas into one of two adsorption cylinders filled with an adsorbent to adsorb and dehumidify it. The drying process and part of the dry gas obtained by this drying process are guided to the other adsorption column whose hygroscopic capacity has decreased in the previous drying process to desorb moisture from the adsorbent and adsorb the desorbed moisture. The regeneration process of purging from the cylinder is performed in parallel, and the drying process and the regeneration process are alternately switched between the adsorption cylinders to continuously supply the dry gas. is stopped, you have rows regeneration step at a predetermined cycle during this stop, or
While the regeneration process is stopped, the drying process is alternated between both adsorption tubes.
It is characterized in that it is continued, or only one adsorption cylinder is continued .

[0012]

In order to satisfy the above object, a dehumidifying device for compressed gas of the present invention comprises two adsorption cylinders filled with an adsorbent, a communication passage communicating these adsorption cylinders through a switching means, and a purging means. Then, the moist compressed gas is guided to one of the adsorption cylinders to be adsorbed and dehumidified and dried, and a part of this dried gas is guided to the other adsorption cylinder to desorb the moisture from the adsorbent whose hygroscopic capacity has decreased in the previous stage In addition, the regeneration of purging the desorbed moisture from the adsorption column by the purging unit is performed in parallel, and the drying and regeneration are alternately switched between the adsorption columns based on the switching of the switching unit to continuously generate the dry gas. in dehumidifier supplies, together form a energy saving operation of stopping the regeneration step under predetermined conditions, have rows regeneration step at a predetermined cycle during the energy saving operation, and a drying step while stopping the regeneration step both adsorption
Alternate between cylinders, or only one adsorption cylinder is connected.
The control means for controlling to continue is provided.

By adopting the means for solving such a problem, a so-called energy-saving operation for stopping the regeneration process under a predetermined condition is performed, and at this time also, the forced purging of both in-cylinder adsorbents is performed in a predetermined cycle. By doing so, it is possible to evenly progress the deterioration of the adsorbent while suppressing the purge amount to a small amount, and to suppress the fluctuation of the dew point temperature between the adsorption cylinders when returning to the standard operation, and the timing of the adsorbent replacement. Can be taken at the same time.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a perspective view of the appearance of a dehumidifier for compressed gas. This dehumidifying device includes a pedestal 1 on the lower side, an electric component box 2 mounted on one side of the pedestal 1, and two adsorption cylinders mounted on the other side of the pedestal 1 (for convenience of explanation, Hereinafter, the left suction cylinder in the figure is called the A cylinder,
The suction cylinder on the right side of the figure is called the cylinder B) 3, 4, and these A, B
It comprises an outlet head 5 mounted over the upper ends of the cylinders 3 and 4, and an inlet head (not shown here) mounted over the lower ends of the cylinders A and B.

The outlet head 5 is attached and fixed to the pedestal 1 through a plurality of support bolts 6 ... And nuts 7, so that the A and B cylinders 3 and 4 are fixed and held. The inlet head is shielded by a cover plate 8 attached to the gantry 1.

On one side surface of the outlet head 5,
An inlet / outlet 9 is provided for guiding the gas adsorbed and dried in the apparatus to a predetermined supply destination, and an inlet 1 for guiding the wet compressed gas into the apparatus is provided on one side surface of the gantry 1.
0 is opened.

A humidity indicator 11 is provided at the center of the outlet head 5 and contains a member which comes into contact with the adsorbed and dried gas and changes its color when the gas exceeds a predetermined relative humidity. . That is, the humidity indicator 11 detects the degree of deterioration of the adsorbent contained in the A and B cylinders 3 and 4.

Further, the outlet head 5 has A, B
Purge orifice 1 communicating with the upper ends of both cylinders 3 and 4
Two are provided. A pair of connection ports 13 for connecting a purge valve described later are provided on the side opposite to the purge orifice 12.

FIG. 2 and FIG. 3 schematically show the cross section of the same adsorption device, which are in different states of action. Each of the A and B cylinders 3 and 4 is composed of a cylinder body whose upper and lower end surfaces are open. The upper end opening portion is inserted into the recess 5a provided on the lower surface of the outlet head 5, and the lower end opening portion is described above. It is fitted into a recess 15 a provided on the upper surface of the inlet head 15.

Then, the perforated plate 16 is provided at a position spaced from the upper end opening and the lower end opening of the A and B cylinders 3 and 4, respectively.
Is provided, and the adsorbent 17 is filled between the perforated plates 16. As the adsorbent 17, activated alumina, silica gel, zeolite or the like is used.

Each A in the outlet head 5,
Check valves 18A, 18 are provided at positions facing the central portions of B cylinders 3, 4
A valve chamber 19 that accommodates B is formed. These check valves 18
A and 18B allow the gas flow upward from the inside of the cylinders 3 and 4 on the lower side, and prevent the gas flow from the upper part into the cylinders 3 and 4.

Further, the outlet head 5 is provided with a supply / discharge passage 20 which communicates the supply outlet 9 with each valve chamber 19, and the check valves 18A and 18B are opened to open the valve chamber 19.
The gas that has flowed out of the chamber is guided to the supply / discharge port 9. In addition,
A branch passage 21 that communicates with the humidity indicator 11 is provided in the supply passage 20 in a branched manner.

Around the respective valve chambers 19, recesses are formed within the range where the A and B cylinders 3 and 4 are fitted, and the purge orifice described above (here, it is drawn so as to be provided in the outlet head 5 is drawn. The purge chamber 22 communicates with the (12). In other words, the purge chambers 22 and 22 are communicated with each other by the purge orifice 12.

The end of the supply / discharge path 20 opposite to the supply / discharge port 9 is closed, and a humidity sensor 23 is attached therethrough. As shown only in FIG. 2, a control circuit 25 as a control means is housed in the electric component box 2 and electrically connected to the humidity sensor 23. The humidity sensor 23 detects the humidity of the dry air in the feed passage 20 and sends the detection signal to the control circuit 25.

A switching valve 26, which is a switching means, is attached to the lower surface of the inner head 15. The inlet 10 is provided on one side of the inner head 15, and a purge valve 27 and a silencer 28 are connected in series on the other side.

The switching valve 26 includes a first port a, a second port b, a third port c,
The fourth port d and the fifth port e are sequentially provided, and the communication of the ports a to e is switched by moving the valve body f.

That is, at the valve body f position shown in FIG. 2, the first port a and the second port b are communicated with each other, and
The third port c and the fourth port d are communicated with each other. Also,
At the valve body f position shown in FIG. 3, the second port b and the third port c are communicated with each other, and the fourth port d and the fifth port e are communicated with each other.

The valve body f is driven by a solenoid 26S. The solenoid 26S is electrically connected to the control circuit 25 and is drive-controlled as described later.

The inlet head 15 has an inlet 1
0 and the third port c of the switching valve 26 are communicated with each other, an A cylinder communication passage 31 that communicates the lower opening end of the A cylinder 3 with the second port b, and a lower opening of the B cylinder 4. B cylinder communication passage 32 that connects the end and the fourth port d, and the first port a
An inverted U-shaped port communication passage 33 that communicates with the fifth port e and a purge branch passage 34 that branches from an intermediate portion of the port communication passage 33 and communicates with the purge valve 27.

The purge valve 27 is an electromagnetic opening / closing valve having a normal structure, and is electrically connected to the control circuit 25.
It opens and closes in accordance with a control signal from the control circuit 25 to conduct or block the purge gas introduced from the purge branch passage 34. The purge gas derived from here is guided to the silencer 28 to be silenced, and then discharged to the outside.

The control circuit 25 controls the humidity sensor 23.
A circuit for receiving the detection signal from the unit and converting it to a dew point temperature (pressure dew point) Ta, a circuit for comparing this dew point temperature Ta with a preset dew point temperature (pressure dew point) Ts, and the comparison result. Based on the above, the switching valve 26
And a circuit for controlling opening / closing of the purge valve 27.

An adsorption device having such a structure,
It operates as described below. It should be noted that compressed air is applied as the compressed gas in the description.

When the valve body f of the switching valve 26 is in the position shown in FIG. 2, the B cylinder 4 performs the drying process and the A cylinder 3 performs the pressurizing process or the regenerating process. That is, the moist compressed air supplied to the dehumidifier is guided from the inlet 10 of the inlet head 15 to the third port c of the switching valve 26 via the inlet passage 30, and further via the fourth port d. It is guided into the B cylinder 4 from the B cylinder communication passage 32.

While the moist compressed air passes through the inside of the B cylinder 4 from the lower part to the upper part, the adsorbent 17 filled therein adsorbs and dehumidifies it to dry it.
Then, the check valve 18B provided at the upper portion is pushed up to be guided to the supply passage 20 of the outlet head 5, and further supplied from the supply outlet 9 to a predetermined supply destination.

A part of the dry air discharged from the upper end opening of the B cylinder 4 is introduced into the purge chamber 22, and the flow rate is throttled by the purge orifice 12, so that the purge chamber 2 above the A cylinder 3 is filled.
It is guided into the A cylinder 3 via 2. Then, it passes through the adsorbent 17 filled in the A cylinder 3 to desorb the moisture adsorbed by the adsorbent 17 in the drying process of the previous stage.

The purge air, which is the air from which moisture has been desorbed, is led out from the A-cylinder communication passage 31 through the second port b through the first port a and is introduced into the port communication passage 33.
From the place where the fifth port e is in the closed state, the purge air is guided from the port communication passage 33 to the purge branch passage 34.

When the purge valve 27 is in the closed state, the purge air is cut off here, so that the pressure in the A cylinder 3 rises. When the purge valve 27 is in the open state, the purge air passes through the purge valve 27 and is guided to the silencer 28, where it is silenced and then released to the outside.

When the valve body f of the switching valve 26 is in the position shown in FIG. 3, the A cylinder 3 performs the drying process and the B cylinder 4 performs the pressurizing process or the regenerating process. That is, the moist compressed air supplied to the dehumidifier is guided from the inlet 10 of the inlet head 15 to the third port c of the switching valve 26 via the inlet passage 30, and further via the second port b. It is guided into the A cylinder 3 from the A cylinder communication passage 31.

While the moist compressed air passes through the inside of the A cylinder 3 from the lower part to the upper part, the adsorbent 17 filled therein adsorbs and dehumidifies the material to dry it. Then, the check valve 18A provided at the upper portion is pushed up to be guided to the feed passage 20 of the outlet head 5, and further, the feed outlet 9
Is supplied to a predetermined supply destination.

A part of the dry air discharged from the upper end opening of the A cylinder 3 is guided to the purge chamber 22, and the flow rate is reduced by the purge orifice 12, and the dry air is discharged from the purge chamber 22 above the B cylinder 4 to the B chamber 4. Guided in the cylinder 4.

This dry air passes through the adsorbent 17 filled in the B cylinder 4, and the adsorbent 1 is adsorbed in the previous drying process.
The moisture adsorbed by 7 is desorbed. The purge air, which is the air from which moisture has been desorbed, is led out from the B cylinder communication passage 32 through the fourth port d through the fifth port e, and is further introduced into the port communication passage 33.

From the place where the first port a is closed, the purge air is supplied from the port communication passage 33 to the purge branch passage 3.
Guided to 4. When the purge valve 27 is closed, the purge air is cut off here, and the pressure in the B cylinder 4 rises. When the purge valve 27 is in the open state, the purge air passes through the purge valve 27 and is guided to the silencer 28, where it is silenced and then released to the outside.

Next, as shown in FIGS. 4A to 4D, the above dehumidifying action will be described in order from the aspect of switching the flow path configuration.

In FIG. 4A, the moist compressed air is guided to the B cylinder 4 through the switching valve 26 and is adsorbed and dried by the adsorbent 17 filled therein. The dried compressed air is supplied to the supply destination through the check valve 18B.

A part of the dry air discharged from the B cylinder 4 is guided to the A cylinder 3 via the purge orifice 12, but the purge valve 27 is closed and the inside of the A cylinder 3 is pressurized to the operating pressure. . That is, the B cylinder 4 performs the drying process, and the A cylinder 3 performs the pressurizing process.

In FIG. 4B, the switching valve 26 is switched and the purge valve 27 is opened. The moist compressed air is guided to the A cylinder 3 through the switching valve 26, and the adsorbent 17
By adsorption and drying.

Dry compressed air is delivered through the check valve 18A. A part of the dry air discharged from the A cylinder 3 is guided to the B cylinder 4 through the purge orifice 12 to desorb the moisture from the adsorbent.

The purge air is released from the purge valve 27.
Is guided to the silencer 28, and is discharged to the outside from here. That is, the A cylinder 3 performs the drying process and the B cylinder 4 performs the regeneration process.

In FIG. 4 (C), the switching valve 26 maintains the same state, while the purge valve 27 changes to the closed state. Therefore, the A cylinder 3 is subsequently subjected to the drying process, and the B cylinder 4 is subjected to the pressure increasing process of increasing the pressure to the operating pressure.

In FIG. 4D, the switching valve 26 is switched and the purge valve 27 is changed to the open state. The moist compressed air is guided to the B cylinder 4 via the switching valve 26, and is adsorbed and dried by the adsorbent 17 that has finished regeneration.

The dried compressed air is supplied via the check valve 18B. A part of the dry air discharged from the B cylinder 4 is guided to the A cylinder 3 through the purge orifice 12 to become the purge air in which moisture is desorbed from the adsorbent 17, and the purge air is discharged from the silencer 28 via the purge valve 27. It is released to the outside.
That is, the B cylinder 4 performs the drying process, and the A cylinder 3 performs the regeneration process.

After that, the state is changed to the state of FIG. 4A again, and the above four steps are sequentially repeated.

During the standard operation, the control as shown in FIG. 6 is performed. That is, since the control circuit 25 controls the switching valve 26 to switch at an interval of 2 minutes, the switching between the drying process for adsorbing and dehumidifying in the A cylinder 3 and the drying process for adsorbing and dehumidifying in the B cylinder 4 takes about 2 minutes. Done at intervals.

Then, the control circuit 25 controls the opening of the purge valve 27 at substantially the same timing as the switching of the switching valve 26, and controls the closing of the purge valve 27 before the switching valve 26 is switched next time.

For example, the purge valve 27 is controlled to be opened a few seconds after the switching valve 26 is switched to perform the drying process of adsorption and dehumidification in the A cylinder 3, and the pressure fluctuation when the regeneration purge in the B cylinder 4 is started. Suppress.

The purge valve 27 is set to open for about 90 seconds, during which the regeneration process in the B cylinder 4 is continued. Then, about 90 seconds after the dehumidifying and drying of the A cylinder 3 is started, the purge valve 27 is closed, so that the B cylinder 4 starts the pressure increasing step.

The pressurizing process is continued for about 30 seconds in the B cylinder 4, and after a total of about 120 seconds (2 minutes), the switching process of the switching valve 26 and the drying process for adsorbing and dehumidifying in the B cylinder 4 is continued for 120 seconds. A few seconds after this switching, the purge valve 27 is controlled to be opened, the regeneration process is continuously performed for about 90 seconds on the A cylinder 3 side, and then the purge valve 27 is closed for about 30 seconds to perform the pressure increasing process on the A cylinder 3 side. change.

After all, after continuing for about 120 seconds (2 minutes), the process of the adsorption and dehumidification on the A cylinder 3 side and the regeneration and pressurization process on the B cylinder 4 side are changed again as described above.
Repeat in the following order.

The humidity sensor 23 detects the humidity of the compressed air that has been dehumidified by adsorption and sends a detection signal to the control circuit 25, which calculates the dew point temperature (pressure dew point) Ta and outputs the result to the sensor output. Output as voltage.

For example, when the so-called load is small, for example, the amount of air required at the destination supplied from the supply outlet 9 is very small, or the humidity of the compressed air introduced from the inlet 10 is extremely low and dry. In this case, shift to energy saving operation.

Actually, the energy saving operation is switched from the standard operation based on the flowchart shown in FIG. That is, the standard operation is started in step S1 from the start. From this standard operation, the process moves to step S2, and the humidity sensor 23 detects the humidity of the dry air supplied.

In step 3, the control circuit 25 receiving the detection signal from the humidity sensor 23 calculates the dew point temperature (pressure dew point) Ta. Then, in step S4, the control circuit 25 compares the preset dew point temperature (pressure dew point) Ts stored in advance with the calculated dew point temperature Ta.

The calculated dew point temperature Ta is the set dew point temperature Ts.
Lower than or equal to (Ta ≦ Ts),
If Yes, the process moves to step S5, and the energy saving operation described later is started. Further, if the calculated dew point temperature Ta is higher than the set dew point temperature Ts, the determination result is No and the step S1 is performed.
Return to normal operation.

FIG. 7 shows the control in the energy saving operation. The set dew point temperature Ts stored in advance in the control circuit 25 is, for example, a pressure dew point of −40 ° C., and the calculated dew point temperature Ta is calculated.
Is equal to or lower than this set dew point temperature Ts, the energy saving operation start signal is issued below.

The switching valve 28 is used for dehumidifying and drying the A cylinder 3 and the B cylinder 4.
The dehumidifying / drying is switched at intervals of 2 minutes as described above. Then, the purge valve 27 is opened to perform the regeneration purge of the B cylinder 4 almost at the same timing as the switching of the dehumidifying and drying to the A cylinder 3, and then the purge valve 27 is closed to increase the pressure. After 2 minutes, the regeneration purge of the A cylinder 3 is performed almost at the same timing as the switching of the dehumidifying and drying of the B cylinder 4, and then the pressure is increased.

Since the load is very small or the humidity of the introduced compressed air is very low, the dew point temperature drops from -40 ° C to -45 ° C. Further, although the switching control for the switching valve 26 continues every two minutes, the purge valve 27
Holds the closed state. From this, the A cylinder 3 and the B cylinder 4
The moist compressed air is introduced almost uniformly to the adsorbents 17 in the cylinders 3 and 4 so as to have the same adsorbing action. for that reason,
The dryness of the supplied dry air does not change and is kept constant.

Since there is no purge of the moisture desorbed from the adsorbent 17 due to the closing of the purge valve 27, the dew point temperature Ta
Gradually rises again from -45 ° C. After such switching of the switching valve 26 is performed for a predetermined cycle (for example, 3 cycles: 12 minutes), the purge valve 27 is controlled during the next one cycle of switching the dehumidifying and drying of the A and B cylinders 3 and 4. It

That is, the purge valve 27 is controlled in the fourth cycle with reference to the first switching cycle of the switching valve 26. Specifically, the regeneration purge of the B cylinder 4 is performed at substantially the same timing as the switching of the dehumidifying and drying of the A cylinder 3.
A timed with the switching of dehumidifying / drying of the B cylinder 4
Regeneration purging of the cylinder 3 is performed.

From this, the moisture accumulated in the A and B cylinders 3 and 4 is forcibly purged by repeating the dehumidifying and drying during the energy saving operation, and the adsorption degree of the adsorbent 17 is recovered to some extent.

Thereafter, the switching valve 2 as described above is again used.
Continuation of the switching control of 6 and the purge valve 27 every 4 cycles
Is controlled. The above pattern does not change during the energy saving operation.

A so-called energy-saving operation is performed in which the amount of purge can be reduced to reduce energy loss. Then, since the adsorbent 17 in each of the cylinders 3 and 4 is forcibly purged every predetermined cycle, deterioration of the adsorbent 17 is suppressed to a minimum.

When the load returns to the original state or the humidity of the compressed air introduced again rises, the set dew point temperature T
Since the calculated dew point temperature Ta becomes higher than s, the control circuit 25 controls again to return to the standard operation of the full flow rate described above.

Even after returning to standard operation, A,
B Since the adsorbent 17 in each of the cylinders 3 and 4 is subjected to the regeneration step of forcibly purging the desorbed moisture evenly, the dew point of the obtained dry air hardly changes.

Further, during the energy saving operation, the deterioration of the adsorbent 17 in the A and B cylinders 3 and 4 progresses evenly,
Therefore, when it is necessary to replace the adsorbent 17, the adsorbents 17 of the A and B cylinders 3 and 4 may be replaced at the same time.

During the energy saving operation for stopping the regeneration process described above, the purge valve 27 is controlled to be opened every four cycles of dehumidification / drying switching for the A and B cylinders 3 and 4 of the switching valve 26. , But is not limited to this.

As shown in FIG. 8A, the purge valve 27 may be controlled to be opened every 5 cycles of dehumidification / drying, and the number of cycles depends on, for example, the dew point of the air after the adsorption and drying. It can be appropriately changed according to various conditions such as judgment and response.

Further, during the energy-saving operation, the dehumidifying / drying switching of the switching valves 26 for the A and B cylinders 3 and 4 is not limited to being alternately performed. For example, as shown in FIG. 8 (B), while stopping the regeneration step by closing the purge valve 27, the switching valve 26 from the A tube 3 B cylinder 4 in switching the or <br/> or state It may be an energy-saving operation in which

However, even in this state, the purge valve 27 must be controlled to be opened in a predetermined cycle, and the adsorbent 17 in each of the cylinders 3 and 4 must be forcibly purged evenly. is there.

[0080]

As described above, according to the present invention, in so-called energy-saving operation, the forced purge of the adsorbent in each adsorption column is performed in a predetermined cycle.
While maintaining a small amount of dry air discharged by purging, the deterioration of the adsorbent in both adsorption cylinders progresses evenly, and the fluctuation of the dew point temperature between the adsorption cylinders when returning to standard operation is suppressed. The reliability is improved, and the adsorbents of both adsorption cylinders are replaced at the same time to eliminate wasteful replacement, which contributes to a reduction in running cost.

[Brief description of drawings]

FIG. 1 is an external perspective view of a dehumidifier showing an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a dehumidifying device showing the same embodiment.

FIG. 3 is a schematic cross-sectional view of a dehumidifying device showing the same embodiment, illustrating a step different from that in FIG. 2;

FIG. 4 is a view for explaining the dehumidifying action in the same embodiment in order from the switching of the flow path configuration.

FIG. 5 is a flowchart showing the same embodiment until switching from standard operation to energy saving operation.

FIG. 6 is a view for explaining control during standard operation, showing the same embodiment.

FIG. 7 is a diagram illustrating control during energy saving operation according to the same embodiment.

FIG. 8 is a diagram for explaining control during energy-saving operation, which shows another embodiment.

FIG. 9 is a diagram illustrating conventional control during energy-saving operation.

[Explanation of symbols]

17 ... Adsorbent, 3 ... Adsorption cylinder (A cylinder), 4 ... Adsorption cylinder (B cylinder), 26 ... Switching valve (switching means), 27 ... Purge means (purge valve), 23 ... Humidity sensor, 25 ... Control circuit (control means), 30 ... Introduction route, 31 ... A cylinder communication passage, 32 ... B cylinder communication passage, 33 ... Port communication passage, 34 ... Purge branch.

Claims (2)

(57) [Claims] 1. A drying step of introducing a moist compressed gas into one of two adsorption columns filled with an adsorbent to adsorb and dehumidify it, and a part of the dry gas obtained by this drying step in the previous step. In the drying process, a regeneration process is conducted in parallel, in which the moisture is desorbed from the adsorbent and the desorbed moisture is purged from the adsorption cylinder by introducing it to the other adsorption cylinder whose hygroscopic capacity has decreased. In the dehumidification method of compressed gas that alternately switches between both adsorption cylinders and continuously supplies dry gas, an energy saving operation is performed to stop the regeneration process under predetermined conditions, and a predetermined cycle is performed during this energy saving operation. in have line regeneration step, and the dry during the stop of the regeneration step
The drying process is continued alternately between both adsorption tubes, or
The method for dehumidifying compressed gas, characterized in that only the adsorption cylinder of (3) is continued . 2. An adsorption cylinder comprising two adsorbing cylinders filled with an adsorbent, a communication passage connecting these adsorption cylinders via a switching means, and a purging means, and guiding a moist compressed gas to one adsorption cylinder. Adsorption dehumidification and drying, and a part of this dry gas is guided to the other adsorption cylinder to desorb moisture from the adsorbent whose hygroscopic capacity has decreased in the previous stage and to purge the desorbed moisture from the adsorption cylinder by the purging means. In the dehumidifier for compressed gas, which continuously supplies dry gas by alternately switching between drying and regeneration based on the switching of the above-mentioned switching means, under the specified conditions. together form a energy saving operation to stop the reproduction process, the drying step while stopping the energy saving have rows regeneration step at a predetermined cycle during the operation, and the regeneration step
Alternate between both adsorption tubes, or one adsorption
A dehumidifying device for compressed gas, comprising a control means for controlling so that only the cylinder continues .