JP2003065498A - Compressed air supply facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the wasteful consumption of power in the large-scaled compressed air supply facility to contribute to energy saving. SOLUTION: This compressed air supply facility 10 is composed of a main compressor 13, a main tank 11 connected to the main compressor 13 by means of a pipe 12, a plurality of air supply pipes 18 connected to the main tank 11 and having air taking-out branches 22 on the way, a sub-tank 20 connected to terminal ends of the air supply pipes through a common pipe 19, a sub- compressor 21 connected to the sub-tank 20, and a controller 26 for independently or simultaneously operating the main compressor 14 and the sub-compressor 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to compressed air supply equipment, and more particularly to compressed air supply equipment suitable for large-scale compressed air utilization equipment installed in factories and the like.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional compressed air supply facility includes a plurality of air compressors C, a receiver tank T for storing compressed air sent from the air compressors C, and a receiver tank T. And a plurality of air supply pipes 101 connected to the outlet side of the.
Each pipe 101 is provided with a branch pipe 102 for taking out air at a required work site. Further, the receiver tank T is provided with a pressure detection sensor PC, and in order to maintain the pressure in the receiver tank T within a predetermined range, the operation of some air compressors C is stopped when the pressure exceeds a certain pressure, and the pressure is kept constant. When it is further reduced, the stopped air compressor C is operated again.

In such conventional equipment, a plurality of air compressors C are centrally arranged in one place in order to reduce flow path loss to the receiver tank T and facilitate maintenance. Since the pipe pressure loss of the air supply pipe increases toward the end, the discharge pressure (0..MPa) obtained by adding the maximum pipe pressure loss (for example, 0.1 MPa) to the end supply pressure (for example, 0.6 MPa (gauge pressure, the same hereinafter)). 7 MPa
) Is set.

[0004]

In the above-mentioned conventional supply equipment, especially when the air supply pipe becomes long, the pipe pressure loss increases, and the discharge pressure increases accordingly. Therefore, when the load is low, excessive pressure may be generated at the end portion, resulting in wasted power consumption. Furthermore, since the pipe pressure becomes higher, the amount of air leakage increases, resulting in a waste of power. As the piping system and the like become complicated, there is a problem that it becomes difficult to identify the location where the compressed air leaks in the entire piping network.
A first object of the present invention is to reduce wasteful consumption of power in a large-scale compressed air supply facility and contribute to energy saving. Further, the second object of the present invention is to provide a compressed air supply facility that makes it easy to identify the location of air leakage in the piping network.

[0005]

The compressed air supply equipment of the present invention is provided with a main compressor, a main tank connected to the main compressor by a pipe line, and a main tank connected to the main tank. It is characterized in that it is provided with a plurality of air supply pipes having branches and a sub-tank connected to a terminal portion of these air supply pipes via a common pipe. In such compressed air supply equipment, it is preferable that a sub-compressor is connected to the sub-tank and a controller that operates the main compressor and the sub-compressor independently or simultaneously is provided. Further, it is preferable that a stop valve whose opening and closing can be remotely controlled by a controller is interposed at both ends of each of the plurality of air supply pipes. Furthermore, it is more preferable that the main compressor and the sub-compressor have different compression systems from each other.

[0006]

In the compressed air supply equipment of the present invention, the pressure fluctuation at the end of the air supply pipe is leveled by the supply from the sub-tank and other air supply pipes, and does not decrease significantly even under high load. Therefore, the discharge pressure of the main compressor can be made lower than in the conventional case. Then, by reducing the discharge pressure of the main compressor, power can be saved. Moreover, by reducing the discharge pressure, the pipe pressure is reduced, and the amount of leakage is reduced, which also saves power.

In the compressed air supply equipment in which the sub-compressor is connected to the sub-tank, the sub-compressor also operates at high load to maintain the pressure at the end. In that case, since the pressure at the end of the air supply pipe is compensated by the supply from the sub-compressor, the discharge pressure of the main compressor can be lowered. And when the load is low, the sub compressor (or main compressor)
To stop. When the load is low, there is little pressure loss in the pipeline, so there is little pressure reduction at the end even with only the supply from the main compressor. Therefore, there is no problem even if the discharge pressure of the main compressor is lowered. When the load is lighter, only the sub-compressor needs to be operated. Since the controller operates / stops the main compressor and the sub-compressors, management is easy even if they are distributed and they can be finely switched according to changes in load.

When a stop valve is provided at both ends of the plurality of air supply pipes, only one stop valve of the one pipe is opened to detect the air supply leak, thereby determining the leak amount of the pipe. Can be easily detected. The leak system and the leak amount can be easily specified by sequentially detecting the leak in each pipe. In particular, if both ends of a plurality of air supply pipes are respectively connected to the main tank and the sub tank, the network becomes complicated and it is difficult to specify the position of the leak. Therefore, by partitioning the network with such a stop valve, it becomes easier to find the leakage system and the leakage amount.

When the compression methods of the main compressor and the sub-compressor are different from each other, it is possible to select and operate a compressor having an appropriate operating characteristic according to the change situation of the load.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a compressed air supply facility of the present invention will be described below with reference to the drawings. FIG. 1 is a piping system diagram showing an embodiment of a supply facility of the present invention, FIG.
a is an explanatory view showing an air flow of one air supply pipe of the supply equipment, FIG. 2b is a schematic graph showing a pressure loss of the air supply piping, and FIG. 3 is another embodiment of the supply equipment of the present invention. It is a piping system figure shown.

The supply equipment 10 shown in FIG. 1 includes a main tank 11 and a plurality of main compressors 13 connected to the inlet side of the main tank 11 by a pipe 12.
14, a common pipe 17 connected to the outlet side of the main tank 11 via a pipe 16, and a plurality of supply pipes 18 each having one end connected to the common pipe 17. The other ends of the supply pipes 18 are both connected to another common pipe 19, and the common pipe 19
Is connected to the outlet side of the sub tank 20. A sub compressor 21 is connected to the inlet side of the sub tank 20.

A branch pipe 22 for connecting to an air using device such as an air cylinder used in a factory is connected to each supply pipe 18. In addition, each supply pipe 1
A stop valve 23, which can be opened and closed by remote control, is provided at the end of the main tank 11 on the side of the main tank 11. Similarly, the stop valve 2 that can be remotely operated is also provided at the other end of the supply pipe 18.
4 is interposed. Those stop valves 23, 2
The control unit of No. 4 is connected to the controller 26 by the communication line 25. Further, the main tank 11 is provided with a pressure sensor 28, and the output signal thereof is connected to the control unit of the main compressors 13, 14, 15 via a communication line 29. At the same time, the pressure sensor 28 of the main tank 11 is connected to the controller 26 by a communication line 30. Similarly, the sub tank 20 is also provided with a pressure sensor 31, and its output signal is connected to the sub compressor 21 and the controller 26 by communication lines 32 and 33.

Main tank 11 and main compressor 1
3, 14, 15, the common pipe 17, the plurality of supply pipes 18, and the pressure sensor 28 of the main tank 11 may be the same as those used in the conventional compressed air supply equipment. That is, the main tank 11 is a pressure resistant container made of steel of about 30 to 40 liters for a compressor capacity of 1 Kw, which varies depending on the number of main compressors and the load capacity, and is a relief valve or drain cock for preventing overfilling. Is provided. As the main compressors 13, 14, 15, any of conventionally used ones such as a reciprocating type, a turbo type, a screw type can be adopted. The number of units is selected according to the load, but since the sub-compressor 21 can bear a part of the load, the number of units is small.

The pressure sensor 28 of the main tank 11 may be of any type, but may be a diaphragm type pressure sensor, for example. In addition, normally, as in the case of the conventional supply equipment, a pressure sensor 28 and a memory for storing the set pressure,
Also, control devices such as a programmable controller are integrated to control the number of operating main compressors 13, 14, 15 from 0 to 3 units. Then, the set value of the pressure sensor 28 is preferably set by the entire controller 26. However, the overall controller 26 may directly control the number of units.

The overall controller 26 includes a CPU, an arithmetic memory, a memory for storing programs, and an input / output.
A device having an output terminal or the like is used. However, it may be a programmable controller or the like. Thereby, it is possible to instruct an appropriate operation pattern according to various situations such as an operation situation and a change in load. Further, it is preferable that the stop valves 23, 24 can be manually opened and closed according to the arrangement of loads in the factory.

The sub tank 20 may be substantially the same as the main tank 11. The capacity is set according to the capacity of the sub-compressor 21 to be connected. The standard of the capacity is the same as that of the main tank described above.
The pressure sensor 31 may be the same as the pressure sensor 28 of the main tank 11. The set pressure in the sub-tank 20 is usually 0.05-
0.1Mpa Set higher or lower. This makes it possible to switch between base operation and operation that absorbs load fluctuations. However, it may be the same as the main tank 11.

The stop valve 23 may be of any type such as a sluice valve and a butterfly valve, but it is preferable that the loss of the flow passage when the valve is open is as small as possible. The operation shaft for opening and closing is connected to a driving element such as a motor and electrically controlled so that it can be opened and closed by remote control from the controller 26. The common pipe 19 on the sub-tank side may have the same thickness as the common pipe 17 on the main tank side. However, a thinner one may be used. In that case, the thickness will correspond to the capacity of the sub-compressor.

The supply facility 10 constructed as described above is
For example, use as follows. [Normal operation] Generally, the set pressure of the main tank 11 and the set pressure of the sub tank 20 are shifted. However, the same set pressure can be used. In any case, the set pressure of the main tank 11 can be made lower than that of the conventional supply facility (see FIG. 4) in which compressors are centrally arranged.

That is, in the supply installation shown in FIG. 2a,
In the conventional case (corresponding to when the stop valve 24 on the sub tank 20 side is closed in FIG. 2A), compressed air is supplied from one side of the supply pipe 18, flows out from the branch pipe 22, and is connected to the branch pipe 22. It is consumed by equipment (load) that uses compressed air. Therefore, the compressed air in the supply pipe 18 flows in one direction from the upstream side to the terminal end, as indicated by an imaginary line arrow N1. The pressure distribution thereby gradually decreases towards the end, as shown by the phantom line M1 in FIG. 2b. The pressure loss s1 at the end portion increases as the flow rate in the pipeline increases, and becomes lower than the pressure P1 of the main tank 11 by about 0.1 MPa in the rated operation (or 100% operation). Therefore, the working pressure p at the end is 0.6
If the pressure is MPa, the set pressure P1 of the main tank needs to be set to about 0.7 MPa, for example.

On the other hand, when the pressure p at the end of the sub-tank 20 and the sub-compressor 21 is maintained at 0.6 MPa, the compressed air in the supply pipe 18 flows from both ends toward the center as indicated by the solid arrow N2. Flow and its flow rate is about 1
It becomes about / 2, and the length of the flow channel becomes about 1/2 on average. Therefore, as shown by the solid line M2, the pressure distribution is low at the center and high at both ends, and is averaged over the whole, and the maximum pressure loss s2 is about 1/8. Therefore, the set pressure P2 of the main tank 11 is about 0.61 MPa. The same set pressure may be applied to the sub tank 20.

By thus reducing the set pressure of the main tank 11, the main compressors 13, 1
The discharge pressures of 4 and 15 can be lowered to the same extent, and the required power can be reduced. That is, from the relationship between pressure and air power, if the discharge pressure is reduced by 0.1 MPa, the power will be about 10
% Can be reduced.

Further, if the pressure in the main tank is lowered and the pipe pressure is lowered, the amount of leakage is also reduced, and, for example, the discharge pressure is 0.
If it decreases by 1Mpa, the leakage amount will decrease by about 6%.

By thus providing the sub-tank and the sub-compressor on the terminal side of the supply pipeline, the discharge pressure of the main tank is reduced and the leakage due to it is reduced, thereby achieving energy saving.

[Unit control] When the load is reduced, the number of main compressors operating is reduced to two or one while the sub-compressor is operating. Further, if the load is further reduced, the operation of the sub-compressor is stopped. As a result, the total energy consumption can be reduced.

[Adjustment of Tank Set Pressure] In the case of the above-mentioned unit number control operation, the main tank 11 and the sub tank 2
By changing the pressure set value of 0, it is possible to select an efficient machine as the base operating machine according to the load fluctuation state, and further achieve the energy saving effect. For example, when the main compressor is a turbo type, the sub-compressor is a screw type, and the load variation is large, the set pressure on the sub-tank 20 side is increased to increase the operating time of the sub-compressor 21 that is efficient with respect to the load variation. On the contrary, when the fluctuation of the load is small, the energy used can be further reduced by increasing the set pressure of the main tank 11 and prolonging the operating time of the turbo type main compressors 13, 14, 15 with good rated operating efficiency. .

[Leakage Detection] Further, in the supply equipment 10 of FIG. 1, since both ends of each supply pipe 18 are connected to the common pipes 17 and 19, air will flow in from both sides of the pipe. Therefore, in the supply facility 10 of FIG.
Remotely controlled stop valves 23, 24 are provided at both ends of 8. Therefore, for example, when the apparatus is stopped, the stop valves 23 and 24 are all closed and the main tank 1
By sequentially opening the stop valves 23 on the one side one by one, the leak system and the leak amount can be easily specified. The stop valves 23 and 24 can be opened and closed by manually operating the controller 26 as described above, but can also be automatically and sequentially performed by using a predetermined program. In that case, the pressure sensor 28 of the main tank 11 detects a change in pressure. The amount of leakage can be determined, for example, by the ratio of the time from the start of operation of the compressor until the pressure reaches a predetermined value, and the time for the pressure to drop after the compressor is stopped.

[Separation operation] In the supply facility 10 of FIG. 1, the first and second supply pipes 18 from the top are
The stop valve 23 on the main tank side is opened and the stop valve 24 on the sub tank 20 side is closed. On the other hand, for the third and fourth supply pipes 18, the stop valve 23 on the main tank side is closed and the stop valve 24 on the sub tank 20 side is opened. Stop valve 2
By opening and closing 3, 24, the plurality of supply pipes 18 can be divided into two groups, and the compressors 21 or the compressor groups (13, 14, 15) for supplying air can be assigned to each group. In that case, the supply pressure is the same as in conventional equipment. However, in equipment where the compression method of a plurality of compressors is changed, for example, the main compressors 13, 14, 15 are reciprocating type, and the sub-compressor 21 is turbo type, pulsation may occur depending on the requirements of the usage site in the factory. It is possible to supply air in appropriate conditions such as air that may be present or air that has as little pulsation as possible.

The supply facility 10 in FIG. 1 has one sub-compressor 21, but it may have two or more sub-compressors 21 as in the supply facility 40 shown in FIG. Figure 3
In this case, two sub tanks 20a and 20b are connected to both ends of the common pipe 19 on the terminal side, and sub compressors 21a and 21b are connected to the respective sub tanks. Other configurations are substantially the same as those of the supply facility 10 of FIG. When three or more compressors are used in this way, it is possible to meet the demands of more diverse factory use sites by changing the compression type of each compressor to, for example, a reciprocating type, a turbo type, or a screw type. Two or more sub-compressors 21a, 2
1b can also be connected to one sub-tank like a main compressor. However, it is preferable to provide them in separate sub-tanks 20a and 20b, respectively, so that the base machines can be selected depending on the load conditions. In addition,
Since the air from the two sub-compressors 21a and 21b is individually supplied to the supply pipe 18, a stop valve 41 that opens and closes by remote control may be provided in the middle of the common pipe 19 as shown by an imaginary line.

In each of the above embodiments, the sub-compressor is connected to the sub-tank. However, the sub-compressor may not be provided, and the end sides of a plurality of supply pipes may be simply connected by a common pipe, and the sub-tank may be connected to the common pipe. In that case, the pressure decrease of one supply pipe can be compensated from another supply pipe through the common pipe or from the sub tank, so that the set pressure of the main tank can be somewhat lowered. As a result, the energy saving effect is smaller than the case where the sub-compressor is provided, but some energy saving effect and leakage reduction effect are expected.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing an embodiment of a compressed air supply facility of the present invention.

FIG. 2a is an explanatory view showing the air flow in one air supply pipe of the supply equipment, and FIG. 2b is a schematic graph showing the pressure loss of the air supply pipe.

FIG. 3 is a piping system diagram showing another embodiment of the supply facility of the present invention.

FIG. 4 is a piping system diagram showing an example of a conventional supply facility.

[Explanation of symbols]

10 supply equipment 11 Main tank 12 piping 13, 14, 15 Main compressor 16 piping 17 Common pipe (main side) 18 Supply piping 19 Common pipe (sub side) 20 sub tanks 21 Sub compressor 22 Branch pipe 23, 24 Stop valve 25 communication lines 26 Controller 28 Pressure sensor 29, 30 communication line 31 Pressure sensor 32, 33 communication line 40 supply equipment 20a, 20b Sub tank 21a, 21b Sub compressor 41 stop valve

Continued front page    (72) Inventor Katsuhiro Yuraki             Daihatsu 1-1 Daihatsu-cho, Ikeda City, Osaka Prefecture             Tsu Industry Co., Ltd. (72) Inventor Jiro Maeyama             3-4-1 Yurakucho, Chiyoda-ku, Tokyo             Machine Industry Co., Ltd. (72) Inventor Kazuhisa Yokota             3-4-1 Yurakucho, Chiyoda-ku, Tokyo             Machine Industry Co., Ltd. F term (reference) 3H076 AA35 AA39 BB31 BB50 CC41                       CC95                 3J071 AA04 BB03 BB14 CC03 CC12                       CC16 DD36 EE38 FF16

Claims (4)

[Claims] 1. A main compressor, a main tank connected to the main compressor by a pipeline, a plurality of air supply pipes connected to the main tank and having a branch for extracting air in the middle thereof, and the air for them. A compressed air supply facility including a sub tank connected to a terminal portion of a supply pipe via a common pipe. 2. A compressed air supply facility comprising a sub-compressor connected to the sub-tank, and a controller for operating the main compressor and the sub-compressor independently or simultaneously. 3. The supply facility according to claim 2, wherein a stop valve whose opening and closing can be remotely controlled by a controller is interposed at both ends of each of the plurality of air supply pipes. 4. The supply facility according to claim 2, wherein the main compressor and the sub-compressor have different compression systems.