JP2001029733A - Switching control method for compressed gas dehumidifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain dry air stably and at the same time, promote the saving of energy by dehumidifying gas by one of adsorbing cylinders at each of a plurality of units and regenerating an adsorbent by means of the other adsorbing cylinder and further, making the confluence of dry gas flows from the units, with an operation to switch the process between the units. SOLUTION: When the valve body (f) of a switching valve 26 is located at a position as illustrated, compressed air is adsorbed by adsorbent 17 to be dehumidified when the compressed air passes through an adsorbing cylinder 4 and thus a dehumidifying process takes place. After that, a part of the dry air is sent out of a delivery aperture 9 through a check valve 18B and a delivery path 20 of an outlet head 5. The residue of the dry air is supplied to another adsorbing cylinder 3 through a purge chamber 22 and a purge orifice 12 and the adsorbent 17 in the adsorbing cylinder 3 dries and desorbs the moisture adsorbed in the drying process of the preceding stage to perform the regenerating process of the adsorbent 17. A plurality of units of the described function are installed and each of the processes is switched between the units at such timing as deviated by 1/ 2 × number of units (n)} cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pair of adsorption cylinders.
The present invention relates to a dehumidifier having a plurality of units as units, and more particularly to a method for controlling switching between standard operation and energy saving operation between units.

[0002]

2. Description of the Related Art In a conventional dehumidifier, since a dry gas, for example, dry air is continuously supplied, a pair of adsorption cylinders filled with an adsorbent such as activated alumina, silica gel, synthetic zeolite or lithium chloride are used. (Two) are prepared.

[0003] A dehumidifying step is performed in which wet compressed air is guided to one of the adsorption columns to obtain dry air by adsorption and dehumidification, and the dry air is supplied to a predetermined supply destination. At the same time, a part of the obtained dry air is led to the other adsorption column, and a regeneration step of desorbing moisture from the adsorbent whose capacity has been reduced due to moisture absorption in the previous stage to regenerate the adsorbent is performed. Purge outside.

[0004] The dehumidifying step and the regenerating step are performed simultaneously in parallel, and after a lapse of a predetermined time, the switching valve is switched to reverse the step in the adsorption column. Thereafter, the switching valve is switched at predetermined time intervals to continuously supply dry air to a predetermined supply destination.

[0005]

By the way, the dew point temperature (dew point under pressure) of the dehumidified compressed air is sufficiently desorbed from the adsorbent when switching from the regeneration step to the dehumidification step. Therefore, it is lowest and gradually rises with moisture adsorption, and rises most when switching from the dehumidification process to the regeneration process. For this reason, each time the dehumidification / regeneration step is switched, the dew point temperature fluctuates greatly and lacks stability.

As a criterion for setting the target value of the dew point temperature, it is necessary to coincide with the end of the dehumidifying step in which the dew point temperature rises the most, and therefore, it is necessary to switch earlier. for that reason,
In states other than the end of the dehumidification process, the dew point temperature tends to be lower than necessary.

In the case of a large-sized dehumidifier in which a plurality of units are provided with a pair of adsorption cylinders as one unit and these units are connected in parallel, if the switching valves of each unit are simultaneously switched at the same timing, the fluctuation range of the dew point temperature is reduced. It will be extremely large.

Depending on the operating conditions, a so-called energy-saving operation is performed in which the moisture desorbed during the regeneration step is not purged to the outside and the amount of purged air discharged is reduced. At the time of switching between the operation and the standard operation, the fluctuation range of the dew point temperature becomes extremely large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a large-sized dehumidifier having a plurality of units, which can switch the timing of each unit during standard operation and save energy. In order to optimize the switching timing during operation, supply dry gas with a small fluctuation range of the dew point temperature to improve accuracy and reliability,
It is an object of the present invention to provide a switching control method in a compressed gas dehumidifier that reduces the amount of purge during energy saving operation and achieves further energy saving.

[0010]

In order to satisfy the above object, a switching control method in a compressed gas dehumidifier according to the present invention is characterized in that a plurality of (n) units are provided with one pair of adsorption cylinders as one unit. In the apparatus, a state in which a dehumidifying step of dehumidifying and drying a gas in one adsorption column of each unit is performed, a regeneration step of the adsorbent is performed in the other adsorption column, and a state in which the dehumidification step and the regeneration step are alternately switched is defined as one cycle. ,
The standard operation of continuously supplying the dry gas by a continuous cycle is performed, the dry gas supplied from each of the above units is combined, and the process switching timing is set to 1 / ｛2 × the number of units ( n)｝ cycle It is characterized by being shifted.

According to a second aspect of the present invention, in the compressed gas dehumidifying apparatus of the first aspect, the switching timing of the energy-saving operation in each unit is set as one set during a predetermined cycle.
It is characterized in that 1 / unit number (n) sets are shifted between units.

By adopting the means for solving the above problems, it is possible to optimize the switching timing of each unit during the standard operation and the switching timing during the energy saving operation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show the same one unit of dehumidifier as a cross-sectional view, and each drawing shows a different operation state. Actually, a large-sized dehumidifier is provided with a plurality of units of the dehumidifier shown in FIG.

As a dehumidifying device of a single unit, a gantry 1
And an electrical component box 2 mounted on one side of the gantry 1
And two suction cylinders mounted on the other side (hereinafter, for convenience of description, the left suction cylinder in the figure is referred to as an A cylinder, and the right suction cylinder is referred to as a B cylinder) 3, 4, and these A and B cylinders It comprises an outlet head 5 mounted on the upper end of 3, 4 and an inlet head 15 mounted on the lower end.

A supply port 9 for supplying and guiding dry gas is provided on one side of the outlet head 5, and an inlet 10 for introducing and guiding wet compressed gas into the apparatus is opened on one side of the inlet head 15. The outlet head 5 has a humidity indicator 11 and a purge orifice 12.
Is provided.

The A and B cylinders 3 and 4 are cylindrical bodies whose upper and lower ends are open. The upper end opening is inserted into the concave portion 5a of the outlet head 5, and the lower end opening is connected to the inlet head 1.
5 is inserted into the recess 15a. Perforated plates 16 are provided at predetermined intervals from the upper and lower ends of the A and B cylinders 3 and 4, and an adsorbent 17 is filled between them. As the adsorbent 17, activated alumina, silica gel, zeolite, or the like is used.

The A and B cylinders 3 of the outlet head 5
A valve chamber 19 is formed at a position opposed to the center of the cylinder 4 so as to accommodate check valves 18A and 18B for allowing a gas flow upward from the inside of the cylinders 3 and 4 and for preventing a gas flow from the upper part into the cylinder. Is done. The outlet head 5 has a supply port 9 and each valve chamber 1.
9 is provided, and a branch path 21 communicating with the humidity indicator 11 is branched.

The periphery of each valve chamber 19 is recessed, and a purge chamber 22 communicating with the purge orifice 12 is formed.
A control circuit 25 is accommodated in the electric component box 2, and a humidity sensor 23 is attached to an end of the supply path 20 opposite to the supply port 9. A switching valve 26 is mounted on the lower surface of the innerlet head 15 and communicates with the inlet 10 and a purge air guide path 34 described later.

The switching valve 26 is provided with a first port a to a fifth port e in order from the left side to the right side in the figure, and the communication between the ports a to e is switched by moving the valve body f. Done. The drive of the valve body f is controlled by a solenoid 26S.

The inlet head 15 has an inlet 1
0, the third port c, communicating with the third port c, the A cylinder communication path 3, which communicates the lower opening end of the A cylinder 3 with the second port b.
1, a B-cylinder communication passage 32 that communicates the lower opening end of the B-cylinder 4 with the fourth port d, a port communication passage 33 that communicates the first port a with the fifth port e, and this port communication passage 3
The purge air guide path 34 branching from 3 is provided.

The purge air guide path 34 is connected in series with a purge valve 27 for conducting and shutting off purge air and a silencer 28 having a fibrous sound absorbing material inside. The control circuit 25 compares the dew point temperature (dew point under pressure) with a circuit that receives the detection signal from the humidity sensor 23 and converts it into a dew point temperature (dew point under pressure). And a circuit for controlling the switching of the switching valve 26 and controlling the opening and closing of the purge valve 27.

In the dehumidifier constructed as one unit as described above, the standard operation described below is performed. Note that compressed air is used as the compressed gas. Switching valve 26
When the valve body f is in the position shown in FIG. 1, the wet compressed air supplied to the apparatus is adsorbed and dehumidified by the adsorbent 17 filled therein while passing through the inside of the B cylinder 4, and is dried. Perform the process. Then, the air is supplied from the supply port 9 to a predetermined supply destination through the check valve 18B and the supply path 20 of the outlet head 5.

A part of the dry air that has flowed out of the B cylinder 4 is guided into the A cylinder 3 from the purge chamber 22, the purge orifice 12, and the purge chamber 22 on the A cylinder 3 side.
A regeneration step of desorbing the adsorbed moisture to regenerate the adsorbent. The purge air from which the moisture has been desorbed is supplied to the A cylinder communication passage 31,
It is led in the order of the port communication path 33 and the purge air guide path 34. If the purge valve 27 is closed, the purge air is shut off and the pressure in the A cylinder 3 is increased. When the purge valve 27 is opened, the purge air is guided to the silencer 28, silenced, and then discharged to the outside.

When the valve body f of the switching valve 26 is at the position shown in FIG. 2, the wet compressed air is guided into the A cylinder 3 to perform a dehumidification process in which it is adsorbed and dehumidified by the adsorbent 17, and is supplied from the supply port 9. Will be issued. In addition, a part of the dry air is led to the B cylinder 4 to desorb the moisture adsorbed by the adsorbent 17 to perform a regeneration step of regenerating the adsorbent. If the purge valve 27 is closed, the pressure in the B cylinder 4 is increased by the purge air, and if the purge valve 27 is open, the purge air is guided to the silencer 28 to be silenced and then discharged to the outside.

For example, as shown in FIG. 3, two units of the single unit dehumidifier described above are provided. As the first unit 1Y, an A cylinder 3a which is an adsorption cylinder
And a B cylinder 4b, and an air compressor C for supplying wet compressed air and a switching valve 26 are connected. The A cylinder 3a and the B cylinder 4b are communicated via the purge orifice 12, and are communicated from the check valves 18A and 18B to a supply destination (not shown) via the merging pipe 35. The second unit 2Y has exactly the same configuration as the first unit 1Y. For convenience of explanation, one suction cylinder is referred to as C cylinder 3c, and the other suction cylinder is referred to as D cylinder 3c.
It is referred to as a cylinder 4d. The other components are assigned the same reference numerals and a new description is omitted.

As shown in FIG. 4, during standard operation,
A cylinder 3a dehumidification in first unit 1Y (B cylinder 4b regeneration)
Switching of cylinder B dehumidification (A cylinder regeneration) is one cycle, and switching of C cylinder 3c dehumidification (D cylinder 4d regeneration) -D cylinder dehumidification (C cylinder regeneration) in the second unit 2Y is one cycle.

The change in the dew point temperature on the outlet side in the first unit 1Y is the lowest temperature DP2 when the dehumidifying process is started in the A-cylinder 3a, and thereafter, the dew-point temperature rises as the dehumidifying of the A-cylinder 3 elapses. At the temperature DP1 that has risen most when the dehumidification process is switched in the A cylinder 3a, the dehumidification process is started next in the B cylinder 4b, and the dew point temperature becomes the lowest. Then, the dew point temperature rises with the lapse of the dehumidification of the cylinder B. When the dew point temperature rises at the time of this switching, the dew point is switched to the dehumidification process in the cylinder A 3a, and the above-mentioned dew point temperature change is observed.

The C cylinder 3c and D in the second unit 2Y
The change in the dew point temperature in the cylinder 4d due to the process switching is exactly the same as the change in the dew point temperature in the first unit 1Y due to the process switching in the A cylinder 3a and the B cylinder 4b. Therefore, here, the change of the dew point temperature is shown in the same figure, and the new description is omitted.

Based on the switching control in the standard operation and the accompanying change in the dew point temperature, the control circuit 25 sets the switching timing between the units 1Y and 2Y to 1 / ｛2n (the number of units). ｝ Cycle is controlled to shift. Here, since two units are provided, (n = 2), and the switching timing is shifted by 1/4 cycle from the above equation.

For example, in the first unit 1Y, the A cylinder 3a
In the second unit 2Y, the dehumidification process has been switched to the D cylinder 4d before １ ／ cycle before switching to the dehumidification process. And
When the cylinder A continues the dehumidification process for 1/4 cycle, the second unit switches the dehumidification process from the cylinder D to the cylinder C 3c.

When the dehumidification of the A cylinder 3a and the D cylinder 4d overlaps, the change of the dew point temperature when the dehumidification process is switched on the A cylinder side, the dew point temperature is in the process of rising from the lowest temperature DP2. On the other hand, on the D-cylinder side, the dew point temperature has risen because the dehumidification step has already been switched to the dehumidification step, and reaches the highest temperature DP2 immediately before switching to the C-cylinder 3c. After all, the dry air supplied from the units 1Y and 2Y is guided to the supply destination after being joined to the merging pipe 35, so the dew point temperature of the dried air after merging is the dew point temperature of the A cylinder 3a and the D cylinder 4d. And an intermediate temperature change between them.

Since the same switching timing continues thereafter, the peaks and valleys of the amplitude of the dew point temperature between the units 1Y and 2Y are complemented with each other, and the highest dew point temperature DP1 until then is newly added. DP1 ', and the lowest dew point temperature DP2 is newly added to DP
Go up to 2 '.

Therefore, it is possible to supply dry air having a small change in the dew point temperature, and a stable dew point temperature zone is obtained. Then, the highest dew point temperature DP1 'is lower than the highest dew point temperature DP1 in the single unit, and the lower target dew point temperature can be cleared.

On the other hand, when the amount of air required at the supply destination is very small, or when the humidity of the compressed air introduced from the compressor C is extremely low and the air is dried, the load becomes low. The control circuit 25 makes a judgment based on the detection signal received from the controller and controls to shift to the energy saving operation. Alternatively, a dew point sensor 40 may be provided in the merging pipe 35, and the determination may be made based on the actual measurement of the dew point temperature.

As shown in FIG. 5 in which the first unit 1Y is applied, the fluctuation range of the dew point temperature is extremely large under a normal load (standard operation), but the switching is performed in a temperature range where the dew point temperature is low at a low load. In addition, even during the energy saving operation, the switching valve 27 switches at the same timing as during the standard operation, and the A cylinder 3a and the B cylinder 4b repeat the dehumidification process at equal intervals. On the other hand, the purge valve 27 is controlled to be closed for a predetermined cycle.

The closing timing of the purge valve 27 is adjusted, for example, when it is confirmed that the energy saving operation has been started in the A cylinder 3a and then the operation is switched to the dehumidification process in the B cylinder 4b. The closing time of the purge valve 27 is determined by the switching valve 26.
Is continued for two cycles. As long as the purge valve 27 is closed, there is no external discharge of purge air, and there is no energy loss and energy is saved.

The lowest dew point temperature DP2 when dehumidifying the B cylinder 4b
When it rises slightly from, switch to A cylinder 3a dehumidification,
Gradually rise. Before the temperature rises to the highest dew point temperature DP1, the operation is switched to the dehumidification of the cylinder B, and the temperature gradually increases from the dew point temperature slightly lowered, and reaches the highest temperature DP1 when the purge valve 27 is closed.

The purge valve 27 is opened at the same time as the switching valve 26 switches to the B cylinder 4b dehumidification process, and the dew point temperature changes in a high range. If the low load condition is maintained as it is, the dew point temperature will exceed the upper limit,
Perform energy-saving operation again at the right time. That is,
The purge valve 27 is closed again at the same timing as when the dehumidification process is switched from the A cylinder 3a to the B cylinder 4b. Hereinafter, the control of the energy saving operation described above is performed.

The energy-saving operation of the unit alone is as described above. In an apparatus having a plurality of units 1Y and 2Y, the switching control is performed at the following timing. As shown in FIG. 6, here, the closing time of the purge valve 27 is continued for three cycles, and if it continues thereafter, the dew point temperature becomes too high, so that the purge valve 27 is opened for one cycle and then closed again. The opening / closing operation described above is repeated.

For example, in each unit 1Y, 2Y,
The three cycles for continuing to close the purge valve 27 and the first and second half cycles thereof are referred to as four sets for one cycle, and the control circuit 25 determines the switching timing of the energy saving operation between the units 1Y and 2Y. 1 / n (number of units) set Control to shift. Here, since two units are provided, (n = 2), and the switching timing of each unit 1Y and 2Y is shifted by セ ッ ト set from the above equation.

The change in the dew point temperature is as shown at the bottom of FIG. For example, when the purge valve 27 is opened and dehumidification is performed in the A cylinder 3a at the beginning of the first set of the first unit 1Y, the dew point temperature slightly increases from the lowest temperature DP2. Since the second unit 2Y is shifted by 1/2 set, the dehumidification process is performed in the C cylinder 3c, the purge valve 27 is kept closed, and the dew point temperature is the highest temperature D at the end of this process.
It becomes P1. Therefore, the dew point temperature of the dry air that has come out of the first unit 1Y and the second unit 2Y and merged is
It is just in the middle temperature zone.

Thereafter, in the first unit 1Y, the B cylinder 4
Switching to dehumidification b, the purge valve 27 is closed. In the second unit 2Y, switching to the D cylinder 4d dehumidification is performed, and the closing of the purge valve 27 is continued. Therefore, each unit 1Y, 2Y
The dew point temperature of the dry air coming out of the chamber is in the middle temperature range, which is not different from the previous state.

Next, in the first unit 1Y, the A cylinder 3a
Switching to dehumidification, the closing of the purge valve 27 is continued, switching to dehumidification of the C cylinder 3c in the second unit 2Y, closing of the purge valve is continued, and the dew point temperature is continued from the previous switching. To rise. In particular, the second unit 2Y alone exceeds the highest dew point temperature DP1 alone, but merges with the dry air from the first unit 1Y in the relatively low dew point temperature range, so that the highest temperature is obtained at the end of this step. Dew point temperature DP
Stay at one.

In the first unit 1Y, the operation is switched to the dehumidification of the cylinder B 4b, and the closing of the purge valve 27 is continued.
In Y, the mode is switched to the D cylinder 4d dehumidification, and the closing of the purge valve 27 is continued. The dew point temperature is not different from the previous state on both the B cylinder 4b side and the D cylinder 4d side, and the dew point temperature change of the combined dry air is exactly the same.

In the next switching, since the timing coincides with the timing of shifting by セ ッ ト set, the above description is replaced with the first unit 1Y by the second unit 2Y, and the second unit 2Y
By replacing the first unit 1Y with the first unit 1Y.

As described above, when the energy saving operation is performed by providing the plurality of units 1Y and 2Y, the switching timing between the units is set, so that the unit where the dew point temperature in the latter half of the setting exceeds the highest temperature is set. , The lower dew point temperature of the other unit is reduced to cover.

That is, the adsorbent 17 can be used without increasing the dew point temperature of the dry air more than necessary during the energy saving operation.
It is possible to extend the life of the device by putting it in a relatively high range so as not to burden the user. Further, the purge time can be made longer, the consumption of compressed air can be further reduced, and more efficient energy saving operation can be performed.

[0048]

As described above, according to the present invention, in a large-sized dehumidifier having a plurality of units, the switching timing between the units during the standard operation and during the energy saving operation is optimized, By supplying a dry gas having a small fluctuation range of the dew point temperature, the accuracy and reliability are improved, and the energy saving operation in which the purge amount is reduced is performed, so that the energy can be further saved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a dehumidifier as a single unit, showing a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the dehumidifier as a single unit, illustrating the same embodiment, illustrating a process different from FIG. 1;

FIG. 3 is a circuit configuration diagram of the dehumidifier having a plurality of units according to the embodiment.

FIG. 4 is a diagram illustrating the same embodiment and illustrating a switching timing between units in a standard operation and a change in dew point temperature.

FIG. 5 is a view showing the embodiment and illustrating a switching timing and a change in dew point temperature during an energy saving operation by a single unit.

FIG. 6 is a view showing the embodiment and illustrating switching timing between units in a standard operation and a change in dew point temperature.

[Explanation of symbols]

17: adsorbent, 3a, 4b, 3c, 4d: adsorption cylinder (A cylinder, B cylinder, C cylinder,
D cylinder), 1Y: first unit, 2Y: second unit, C: compressor, 26: switching valve, 27: purge valve, 35: merging pipe, 25: control circuit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyuki Inoue 246 Yukitaka, Oaza, Suzaka City, Nagano Orion Machinery Co., Ltd. F-term (reference) 4D012 CA01 CB16 CD10 CE01 CE03 CF02 CF03 CF05 CF10 CG01 CJ03 4D052 AA01 CD01 DA02 DB01 FA09 GA01 GA04 GB01 GB03 GB04 GB08 HA01 HA02 HA03

Claims (2)

[Claims] In a dehumidifying apparatus provided with a plurality of (n) units, wherein a pair of adsorption cylinders filled with an adsorbent is one unit, a dehumidification step of dehumidifying and drying a compressed gas wetted by one of the adsorption cylinders in each unit. None, the adsorbent regeneration step is performed by the other adsorption column, and the dehumidification step and the regeneration step are alternately switched between the two adsorption columns as one cycle, and the dry gas is continuously supplied in a continuous cycle. Switching control characterized by performing standard operation, combining dry gas supplied from each of the above units, and shifting the process switching timing by 1 / {2 × the number of units (n)} cycles between the units. Method. 2. The compressed gas dehumidifier according to claim 1, wherein energy saving operation is performed in which the gas containing moisture desorbed from the adsorbent is not purged to the outside during a predetermined cycle for each unit, and one set is provided during the predetermined cycle. A switching control method characterized in that the switching timing of the energy saving operation in each unit is shifted by 1 / unit number (n) between the units.