DEVELOPMENT AND APPLICATION OF ALTERNATIVE DIRECTION AIR COMPRESSOR

DEVELOPMENT AND APPLICATION OF ALTERNATIVE DIRECTION AIR COMPRESSOR Takuya FUJIKAWA*, Osamu OYAMA* and Toshihiro YOSHIMISTU** * Department of Mechanical Engineering, School of Science and Technology Meiji University 1-1-1 Higashimita, Tamaku, Kawasaki city, Kanagawa, 214-8571 Japan (E-mail: ce02088@meiji.ac.jp) ** Department of Mechatronic Robot Kanagawa Institute of Technology 1030 Shimoogino, Astugi city, Kanagawa, 243-0292 Japan ABSTRACT This paper deals a new type of compressor that can deliver the air directions alternatively. This compressor is made by replacing the location of inhalation/exhalation air port into proper position of ordinary vane type air compressor. By using the compressor the direction or speed of cylinder can be selected changing the clockwise/counterclockwise rotational direction and the rotational speed of compressor and the extensional solenoid valves are not needed. In this report, we choose components of this compressor. The air motor that composes this compressor is paid to attention, and a new sample is examined. KEY WORDS Key words, Alternative Direction Air Compressor, Air Motor, Energy Saving INTRODUCTION In recent years, the global environmental problems, for example the global warming, have become increasingly serious. Therefore, we must always develop the machine which is designed in consideration of energy saving. In the field of pneumatics, to improve energy conservation and efficiency of the air compressor is a problem to be solved in the near future, because the source of power supply like air compressor use a huge energy. Incidentally as the case may be the pneumatic system requires the air compressor that can deliver the air both directions, that is, inhalation and exhalation from the viewpoint of energy saving. The reason is because it is possible to control the behavior of the pneumatic actuator by selecting the compressed air directions. Such air compressor can be seen in the literature, but is currently not given. Accordingly, the purpose of this study is the development of alternative direction air compressor and the verification of its fundamental characteristics. Furthermore, this study provides the new system which is configured by the alternate direction air compressor. ALTERNATE DIRECTION AIR COMPRESSOR The alternate direction air compressor is a new compressor that can switch the inlet and outlet and change the direction of air flow each other. In previous studies, the compressor that was designed to meet such a

functional specification was producted by hand made but the compressor could not get enough pressure because of the lack of precision of composed parts. So we focused an air motor that is commercially used as an actuator by using the air motor. Fig.1 shows the schema of the alternate direction air compressor. As shown in Fig.1, the compressor is made by air motor driven by the shaft of the electric motor. When the electric motor rotates the clockwise, the port 1 becomes the exhalation port and the port 2 is the inhalation port. On the other hand, when the electric motor rotates the counterclockwise the port 1 becomes inhalation port and the port 2 is exhalation port. This compressor can select the moving direction of cylinder by changing the clockwise or the counterclockwise rotational direction and the speed of cylinder is continuously changed by the rotational speed of compressor. This compressor needs no additional solenoid valve, speed controller and so on, not as the conventional pneumatic system. 1 2 Air moter Electric moter Inverter 1:Exhalation 2: 1: 2:EXhalation Figure 1 The alternate direction air compressor Air Motor In a past study, we suggested air motors which were constructed as the alternate direction air compressor. Table 1 shows specifications of the air motor. The internal structure of this air motor is a complete symmetry, and it may be said that it is the ideal construction for the alternate direction air compressor. Table 2 shows the Output characteristic of the alternate direction air compressor is made by this air motor. Table 1 Specifications of the previous air motor used for compressor TAV2R-030 Rated pressure (MPa) 0.5 Output (W) 220 At max Torque (N m) 1.7 output (0.5 MPa) Revolution (rpm) 1250 Air consumption (L/min) 650 Min starting torque (N m) 3.3 Mass (kg) 5 Interior volume (mm 2 ) 44 Table 2 The Output characteristic of the previous air motor used for compressor (MPa) Exhalation 0.13 0.073 Flow rate Exhalation 49.7 (L/min) 60.0 Total mass (kg) 12 We see from Table 2 that the output pressure of weak and does not sufficient for compressor. TAV2R-30 is the smallest air motor in this series. Therefor we developed the alternate direction air compressor using two types of air motors newly for improvement of the output. Table 3 shows specifications of the new air motors for the alternate direction air compressor. These two air motors differ in the size, but mechanism is a same. At max output (0.5 MPa) Table 3 Specifications of new air motors P1V-S03 P1V-S06 0A0E50 0A0E00 Rated pressure (MPa) 0.6 0.6 Output (W) 300 600 Torque (N m) 0.40 0.82 Revolution (rpm) 7250 7000 Air consumption (l/min) 480 900 Min starting torque (N m) 0.60 1.2 Mass (kg) 1.0 2.0 Electric Motor The alternate direction air compressor is driven by the shaft of the electric motor. The electric motor which we used is an AC motor. We used inverter to control the direction of rotation and the rotational speed of motor, in order to control the pressure and flow rate. Table 4 shows specifications of the electric motor. And Table 5 shows specifications of the inverter. Table 4 Specifications of the electric motor. EFOU-K Rated output (W) 200[4-pole] Rated torque (N m) 1.3 Rated speed (rpm) 1430[50Hz] Mass (kg) 6.7

Table 5 Specifications of the inverter. L100-002MFR Applicable motor 4-pole,200W Rated capacity 0.6kVA Rated input voltage 100-115V 50/60Hz Rated output voltage 3-phase 200-230V Rated output current 1.4A Control method Line to line sine wave PWM Output frequency range 0.5-360Hz Output Characteristic for The Alternate Direction Air Compressor We show the performance of the alternate direction air compressor using these air motors with electric motor in Table 6. The figure 2 shows the pressure in each rotational speed and the figure 3 shows the Flow rate in each rotational speed. Figure 2 in each rotational speed Table 6 Output characteristic for the compressor P1V-S03 0A0E50 P1V-S06 0A0E00 CW 4880 3160 Exhalation Revolution CCW 4860 3330 (rpm) CW 5870 3160 CCW 5870 3330 CW 0.185 0.153 Exhalation CCW 0.188 0.151 (MPa) CW -0.081-0.073 CCW -0.078-0.074 CW 35.3 51.8 Exhalation Flow rate CCW 33.2 51.0 (L/min) CW 35.1 43.0 CCW 33.9 44.8 CW 7.16 16.4 Air capacity Exhalation CCW 6.83 16.2 par a roll CW (ml/rev) 5.98 12.9 CCW 5.78 13.4 Compressor efficiency (%) 54.4 66.0 Total mass 7.7 8.7 CW ; Clockwise CCW ; Counter-Clockwise Figure 3 Flow rate in each rotational speed Compressor Efficiency Because the internal volume and revolution levels of compressor are different, we compared it with the performance as the each compressor. We calculated efficiency from following expressions (1) (2) and show the result in table 7. L 0 = P Q 60 η = L 0 100 L i L 0 : Output of the compressor (kw) P : pressure (MPa) Q : Flow rate (L/min) η : Compressor efficiency (%) L i : Shaft input of the compressor (kw) (1) (2) We decided to use for calculation with a value of the biggest exhalation pressure of Table 6. In addition, a value of Shaft input of the compressor [L i ] is used consumption power energy of AC motor which we

connected. Table 7 Compressor efficiency comparison Air motor Output (kw) Efficiency (%) TAV2R-030 0.108 53.8 P1V-S030A0E50 0.110 54.4 P1V-S060A0E00 0.132 66.0 The Present Problems We aim at the development of the compressor that needs downsizing and the high output. This is contradicting performance. Thus we prepare samples about air motors and AC motor and choose it. About the air motor, the structure of the compression room chooses the samples of methods different conventionally. We adopted the compression method of the vane type, but plan improvement of the output using the compression method of the piston type as the thing which the high output can expect airtightness from highly more. About the AC motor, we prepare a sample with high output power and plan output improvement about the air motor of the vane type. Comparison about The Air Motor We show air motor to use for the choice of the compressor in Table 8. Sample 1 and 2 are the air motor of a vane type suggested conventionally. About the air motor of the radial piston type, we prepared for the thing of the standard that start torque and mass were close in because we compare it with the vane type. There are sample 3 and 4. We inspect each characteristic using these sample, we choice the most suitable component. Table 9 Evaluation of characteristics experiment result of compressor sample Revolution [rpm] [MPa] Flow rate [L/min] Ex. In. Ex. In. Ex. In. No.1 3160 3160 0.153 0.073 51.8 43.0 No.2 4880 58700 0.185 0.081 35.3 35.1 No.3 1460 2670 0.185 0.083 47.2 52.9 No.4 2800 4540 0.255 0.097 36.2 39.3 Table 10 Efficiency comparison of each sample Sample Output (kw) Efficiency (%) No.1 0.132 66.0 No.2 0.110 54.4 No.3 0.146 72.8 No.4 0.154 77.0 Sample Table 8 Comparison of air motor s specifications Compression method Max power [w] Min start torque [Nm] Weight [kg] No.1 Vane 600 1.23 2.0 No.2 Vane 300 0.60 1.0 No.3 Radial piston 135 1.96 2.5 No.4 Radial piston 73.5 0.686 1.45 Figure 4 Exhalation pressure of each sample Results About each sample, we constitute an interactive model compressor using the same AC motor and measure pressure, flow quantity and the number of revolutions of the verge (See Figure 9). And we show the each sample efficiency comparison in the Table 9. In the figure 4 is exhalation pressure of each sample and in the figure 5 is flow rate of each sample. Figure 5 flow rate of each sample

About the pressure, the difference by the air motor s exhalation was of particular note. Though all samples became more lightweight than the air motor which we used, we were able to get high pressure. About the air motor of the vane type, getting high pressure is thought that we were able to put it up to high rotational speed. About the air motor of the radial piston type, getting high pressure is thought that the air tight of the compression room is superiority. In the flow rate, we were not able to get ever-impressive flow rate by the capacity of the compression room having decreased for smaller and lighter air motor. A decrease in flow rate, however, is approximately 30%. It is not a big loss, because weight is lightweight approximately 50%. We prepared near samples of the weight in each compression method, but we did not see different in the pressure or flow rate. New AC Motor We suggest that we use new AC motor for output improvement about the alternate direction air compressor. It is a problem, however, how we choose new AC motor. So we chose an AC motor not to lose the advantage to be able to carry itself of the alternate direction air compressor. Actually, we were based on 11.7[kg] which is total mass of the first alternate direction air compressor and chose an AC motor not to surpass it. Table 11 shows specifications of the electric motor. And Table 12 shows specifications of new inverter that is used to turn new AC motor. Table 11 Specifications of new AC motor. TFO-FK Rated output (W) 400[4-pole] Rated torque (N m) 1.3 Rated speed (rpm) 1410[50Hz] Mass (kg) 8.2 Table 12 Specifications of new inverter. WJ200-004L Applicable motor 4-pole,400W Rated capacity 1.0kVA Rated input voltage 200-240V 50/60Hz Rated output voltage 3-phase 200-240V Rated output current 3.0A Control method Line to line sine wave PWM Output frequency range 0.10-400.00Hz To aim at the high output and rotary level we constituted the alternate direction air compressor using P1V-S060 and AC motor of 400[W] and we examined output characteristic from it. In addition, we compared it about each compressor. We show the combination of air motor and AC motor that was compared in table 13 Table 13 Combination of air motor and AC motor The alternate direction air compressor Air motor AC motor Sample 1 P1V-S060 A0E00 [400W] Sample 2 P1V-S060 EFOU-K A0E00 [200W] Sample 3 P1V-S030 EFOU-K A0E50 [200W] Total mass 10.2[kg] 8.7[kg] 7.7[kg] Results First, we show below result of a measurement about Sample 1. We show output characteristic for Sample 1 in Table 11. In addition, we show the pressure in each number of revolutions in Figure 5 and Figure 6 and the flow rate in each number of revolutions in Figure 7 and Figure 8. Second, we compare sample 1 to the others. Figure 9 shows pressure and Figure 10 shows flow rate each sample in exhalation when each sample turns clockwise. Furthermore, we show compressor efficiency comparison about each sample in Table 12. Table 11 Output characteristic for Sample 1 Revolution (rpm) (MPa) Flow rate (L/min) Sample 1 Exhalation 3920 5183 Exhalation 0.254-0.085 Exhalation 54.8 50.3 Compressor efficiency (%) 58.0 Total mass 10.2 CW ; Clockwise CCW ; Counter-Clockwise Table 12 Compressor efficiency about each sample Air motor Output (kw) Efficiency (%) Sample 1 0.232 58.0 Sample 2 0.132 66.0 Sample 3 0.110 54.4

Figure 6 of each sample compressor at a high rotary level and succeeded in measurement of the max pressure and flow quantity together. The important part of this argument is that the compressor is useful as a movable small compressor. But we have a problem that the compressor produces heat when we operate it at a high rotary level. Because it is thought that this leads to loss of the energy, the construction of the system which can remove heat effectively is necessary. In addition, because compressor efficiency falls by the improvement of the rotary level, we think about the changes of the compression method of the air motor and want to develop a more efficient interactive model compressor. REFERENCES 1. Takeyuki Sasaki, Osamu Oyama and Toshihiro yoshimitsu, Development and Application of Alternate Direction Air Compressure, The JFPS Symposium on Fluid Power, 2010 2. Takeyuki Sasaki, Osamu Oyama and Toshihiro yoshimitsu, Development and Application of Closed system, 2011. Figure 7 Flow rate of each sample First, we have verified that the pressure is 0.254 [MPa], the flow rate is 54.8 [L/min] and the revolution is 3920 [rpm] in exhalation when sample 1 turns clockwise by this experiment. And we identified the compressor efficiency that is 58.0 [%] by these results. The difference of output by the rotatory direction is not seen. Second, in figure 6 and figure 7, the sample 1 s performance is higher than sample 2 s in a high rotary level. Sample 1 s compressor efficiency is lower than sample 2. We would suggest that it is caused by the development of fever in the alternate direction air compressor. CONCLUSION In this study, we developed a new-type alternate direction air compressor is constructed by a air motor or a new AC motor. About air motor, we prepared near samples of the weight in each compression method, but we did not see the difference by the air motor s exhalation was of particular note in the pressure or flow rate. About AC motor, we succeeded in using the