Connection device

Abstract

To provide a connection device that allows switching of connection states with a simple configuration. [Solution] The connecting device is connected to a first pump, a second pump, and a suction space. The connecting device comprises a first flow path connecting the first pump and the suction space, a second flow path connecting the second pump and the suction space, a third flow path connecting the first pump and the second pump, a first conduit communicating with the second and third flow paths, a valve, and a first space communicating with the suction space. The valve opens the third flow path and closes the second flow path when the air pressure in the first space falls below a predetermined air pressure.

Description

Technical Field

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[0001] The present invention relates to a connection device.

Background Art

[0002] When a plurality of pumps are connected to a suction target such as a vacuum vessel, a technique for switching the connection state of the plurality of pumps from a parallel state to a series state is known. For example, a technique using a switching valve that switches between a parallel state in which the suction ports and inlets of a plurality of micropumps communicate and a series state in which the suction port and inlet of any one of the micropumps communicate is known. In addition, a technique in which a series state and a parallel state can be selected via a switching magnet is also known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above technique, a controller for performing the opening and closing operation of the switching valve is required, and energization of the switching magnet is also required, which hinders miniaturization and power saving of the device.

[0005] On one side, an object is to provide a connection device capable of switching the connection state with a simple configuration.

Means for Solving the Problems

[0006] In one embodiment, the connecting device is connected to a first pump, a second pump, and a suction space. The connecting device includes a first flow path connecting the first pump and the suction space, a second flow path connecting the second pump and the suction space, a third flow path connecting the first pump and the second pump, a first conduit communicating with the second and third flow paths, a valve, and a first space communicating with the suction space. The valve opens the third flow path and closes the second flow path when the air pressure in the first space falls below a predetermined air pressure.

[0007] According to one embodiment, the connection state can be switched with a simple configuration. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of a suction system in an embodiment. [Figure 2] Figure 2 shows an example of the pump connection status. [Figure 3] Figure 3 is a cross-sectional view showing an example of the housing of a connecting device in an embodiment. [Figure 4] Figure 4 is an exploded perspective view showing an example of a connection device in an embodiment. [Figure 5] Figure 5 is a cross-sectional view showing an example of a connecting device in an embodiment. [Figure 6] Figure 6 is another cross-sectional view showing an example of a connecting device in an embodiment. [Figure 7] Figure 7 is a perspective view showing an example of a valve in an embodiment. [Figure 8] Figure 8 is another cross-sectional view showing an example of the first state of the connecting device in the embodiment. [Figure 9] Figure 9 is another cross-sectional view showing an example of the first state of the connecting device in the embodiment. [Figure 10] Figure 10 is another cross-sectional view showing an example of the first state of the connecting device in the embodiment. [Figure 11]Figure 11 is a piping diagram of the suction system in the first state of the embodiment. [Figure 12] Figure 12 is a cross-sectional view showing an example of a second state of the connecting device in the embodiment. [Figure 13] Figure 13 is a piping diagram of the suction system in a second state according to the embodiment. [Figure 14] Figure 14 is a perspective view showing an example of a valve in a modified example. [Figure 15] Figure 15 shows an example of a suction system in a modified example. [Figure 16] Figure 16 is a cross-sectional view showing an example of the first state of the connecting device in a modified example. [Figure 17] Figure 17 is a piping diagram showing an example of the first state of the suction system in a modified example. [Modes for carrying out the invention]

[0009] The embodiments of the suction system and connecting device disclosed in this application will be described in detail below with reference to the drawings. Note that the dimensional relationships and ratios of the elements in the drawings may differ from those in reality. There may also be differences in dimensional relationships and ratios between drawings. In some drawings, for the sake of clarity, a coordinate system may be shown in which the direction in which the valve 400, described later, is pressed by the coil spring 50 is the negative Z-axis direction. Throughout the description of the embodiments, the same components are denoted by the same reference numerals.

[0010] [Embodiment] Figure 1 shows an example of a suction system in an embodiment. As shown in Figure 1, the suction system 1 in the embodiment comprises a connecting device 10, a suction space 70, a first pump 610, and a second pump 620. The suction space 70, as well as the first pump 610 and the second pump 620, are connected to the connecting device 10. In the following, the first pump 610 and the second pump 620 may be collectively referred to as pump 600.

[0011] The pump 600 creates a negative pressure in the suction space 70 by sucking the gas in the suction space 70 through the connection device 10. The suction pressure of the first pump 610 will be described assuming that it is substantially the same as the suction pressure of the second pump 620. Note that the suction pressure of the first pump 610 and the suction pressure of the second pump 620 may be different.

[0012] The first pump 610 has a suction part 611 and a discharge part 612. Similarly, the second pump 620 has a suction part 621 and a discharge part 622. The suction part 611 of the first pump 610 is connected to the opening 240 of the connection device 10, and the discharge part 612 is connected to the opening 120 of the connection device 10. Also, the suction part 621 of the second pump 620 is connected to the opening 130 of the connection device 10, while the discharge part 622 communicates with the atmosphere.

[0013] The suction space 70 is a space whose interior becomes negative pressure when sucked by the pump 600. The suction space 70 is a space that can enhance storage performance and storage capacity by evacuating the gas in a space such as a vacuum storage container or a compression bag for clothes, but is not limited thereto. For example, the suction space 70 may be a suction path to a vacuum pump formed when the suction pad of the gripping device and the suction target are in close contact. The suction target may be, for example, a semiconductor wafer container such as a FOUP. The first connection part 71 of the suction space 70 is connected to the opening 230 of the connection device 10 shown by a broken line in FIG. 1. In the connection device 10 shown in FIG. 1, the openings 120, 130, and 240 are formed on the negative direction side of the Y axis, and the openings 110 and 230 shown by a broken line are formed on the positive direction side of the Y axis.

[0014] In this embodiment, the pump 600 may be connected to the connecting device 10 and the suction space 70 in parallel, as shown in Figure 2(a), or in series, as shown in Figure 2(b). Figure 2 shows an example of the pump connection state. In the parallel state, the discharge section 612 of the first pump 610, which is connected to the opening 120 of the connecting device 10, communicates with the atmosphere through the opening 110 of the connecting device 10 shown in Figure 1. Also, the suction section 621 of the second pump 620 is connected to the suction space 70 via the connecting device 10. On the other hand, in the series state, the discharge section 612 of the first pump 610 and the suction section 621 of the second pump 620 are connected via the openings 120 and 130 of the connecting device 10. In this case, the second pump 620 is connected to the suction space 70 via the first pump 610.

[0015] When pump 600 is connected in parallel to the suction space 70, the flow rate of gas drawn from the suction space 70 is approximately doubled, but the air pressure inside the suction space 70 cannot be lowered beyond the minimum negative pressure (first negative pressure) of the first pump 610 or the second pump 620. On the other hand, when pump 600 is connected in series to the suction space 70, the gas flow rate is the same as when there is only one pump, but the suction pressure can be increased, so a higher vacuum level (second negative pressure) than the first negative pressure can be achieved.

[0016] In this case, for example, when the pump 600 is started, it is connected in parallel to the suction space 70, and after the air pressure in the suction space 70 drops to a predetermined pressure (vacuum level improves), it is switched to a series connection, which allows a higher vacuum level to be reached more quickly than can be achieved with a parallel connection. In the following, the state in which the pump 600 is connected in parallel to the suction space 70 may be referred to as the first state, and the state in which the pump 600 is connected in series to the suction space 70 may be referred to as the second state. In addition, the predetermined air pressure at which the connection relationship between the pump 600 and the suction space 70 switches from the first state to the second state may be referred to as the third negative pressure.

[0017] The connection device 10 in this embodiment includes a valve 400 that switches between series connection and parallel connection depending on the air pressure in the suction space 70. Figure 3 is a cross-sectional view showing an example of the housing of the connection device in this embodiment. Figure 4 is an exploded perspective view showing an example of the connection device in this embodiment. Figure 3 shows a cross-section of the housing 20 of the connection device 10 cut along line AA shown in Figure 1.

[0018] As shown in Figure 4, the connecting device 10 includes a housing 20, a coil spring 50, sealing members 311, 312, 321, 322, 327 and 328, and a valve 400. Note that in Figure 4, the openings 110 and 230 shown in Figure 1, as well as some of the internal structure of the housing 20, are omitted from the illustration. The coil spring 50 is an example of a biasing member.

[0019] The housing 20 in this embodiment is a substantially rectangular parallelepiped member made of, for example, metal. The housing 20 has a first conduit 100 as shown in Figure 5 and second conduits 210 and 220 as shown in Figure 6. Figure 5 is a cross-sectional view showing an example of the connecting device in this embodiment. Figure 6 is another cross-sectional view showing an example of the connecting device in this embodiment. Figure 5 shows a cross-section of the connecting device 10 cut along the CC line shown in Figure 3, and Figure 6 shows a cross-section of the connecting device 10 cut along the BB line shown in Figure 3. In the following, the second conduits 210 and 220 may be referred to collectively as the second conduit 200.

[0020] As shown in Figure 3, the first conduit 100 and the second conduit 200 extend in the Z-axis direction. As shown in Figures 3 and 4, the first conduit 100 is formed near the center of the housing 20 in the X-axis direction, and the second conduit 200 is formed on the positive side of the X-axis relative to the first conduit 100. In this embodiment, the second conduit 200 does not intersect with the first conduit 100. Furthermore, as shown in Figure 3, the first conduit 100 and the second conduit 200 are connected by connecting conduits 270 and 280 that extend in the X-axis direction. The connecting conduits 270 and 280 have ends 271 and 281 that open on the positive side of the X-axis.

[0021] As shown in Figure 4, the valve 400 is positioned in the first conduit 100 of the housing 20. Figure 7 is a perspective view showing an example of the valve in the embodiment. As shown in Figure 7, the valve 400 has a shaft portion 450, a plurality of protrusions 410, 420, 430 and 440, and end portions 470 and 480. The valve 400 is formed of, for example, metal.

[0022] The shaft portion 450 extends in the Z-axis direction. The end portion 470 is the positive end portion in the Z-axis direction, and the end portion 480 is the negative end portion in the Z-axis direction. In this embodiment, the diameter of the shaft portion 450 is approximately 3 mm, and the diameters of the ends 470 and 480 are approximately 1 mm. In this case, the area D4 of the positive end face of the end portion 470 in the Z-axis direction is approximately the same as the area D4 of the negative end face of the end portion 480 in the Z-axis direction shown in Figure 7. Also, as shown in Figure 7, the end portion 470 protrudes from the positive end face of the shaft portion 450 in the Z-axis direction, and the end portion 480 protrudes from the negative end face of the convex portion 440 in the Z-axis direction.

[0023] The protrusions 410, 420, 430, and 440 are portions that project radially outward from the shaft portion 450. The protrusions 410, 420, 430, and 440 are formed spaced apart from each other, extending from the positive side to the negative side of the Z-axis. In this embodiment, the diameter of the protrusions 410, 420, 430, and 440 is approximately 5 mm.

[0024] As shown in Figures 4 and 5, the diameter of the first conduit 100 is formed to be approximately the same as the diameters of the protrusions 410, 420, 430, and 440 of the valve 400. In addition, grooves 140, 150, and 160, which have a larger diameter than other parts, are formed in the portion of the first conduit 100 facing the valve 400. For example, groove 160 is formed at the position where it connects to the connecting conduit 280, as shown in Figure 8, and groove 140 is formed at the position where the opening 120 is formed, as shown in Figure 9. Figures 8 and 9 are other cross-sectional views showing an example of the first state of the connecting device in the embodiment. Figure 8 shows a cross-section of the connecting device 10 cut along the DD line in Figure 6, and Figure 9 shows a cross-section of the connecting device 10 cut along the FF line in Figure 5.

[0025] In this case, the protrusions 410, 420, 430, and 440 and the portion of the first conduit 100 excluding the grooves 140, 150, and 160 are in contact without any gaps, as shown in Figure 10. Figure 10 is another cross-sectional view showing an example of the first state of the connecting device in the embodiment. Figure 10 shows a cross-section of the connecting device 10 cut along the line EE in Figure 6.

[0026] In this configuration, a portion of the first conduit 100 is blocked by a portion of the valve 400. For example, the first space 170, which is the positive side portion of the first conduit 100 in the Z-axis direction, is a space blocked from the other portion of the first conduit 100 by a protrusion 410 of the valve 400. Similarly, the second space 180, which is the negative side portion of the first conduit 100 in the Z-axis direction, is a space blocked from the other portion of the first conduit 100 by a protrusion 440 of the valve 400. In this embodiment, the second space 180 communicates with the atmosphere via an atmospheric communication port 190. In the following description, when referring to the coil spring 50, the first space 170, and the second space 180 being in the first state, they may be referred to as coil spring 51, first space 171, and second space 181, respectively.

[0027] As shown in Figure 6, the second conduit 210 is formed on the positive side of the Z-axis, and the second conduit 220 is formed on the negative side of the Z-axis. Furthermore, the cross-sectional area of ​​the second conduit 220 is larger than that of the second conduit 210.

[0028] The openings 110, 120, and 130 described above are connected to the first conduit 100, and the openings 230 and 240 are connected to the second conduits 210 and 220. The openings 110, 120, and 130 are formed to be spaced apart from each other from the positive side to the negative side of the Z-axis, and the openings 230 and 240 are formed to be opposite each other in the Y-axis direction, approximately in the center of the Z-axis.

[0029] Furthermore, the ends of each conduit in the embodiment are sealed by sealing members 311, 312, 321, 322, 327, and 328. The sealing members are, for example, rubber stoppers.

[0030] For example, as shown in Figure 4, the positive end 101 of the first conduit 100 in the Z-axis direction is sealed by a sealing member 311, and the negative end 102 in the Z-axis direction is sealed by a sealing member 312. Similarly, the positive end 211 of the second conduit 220 in the Z-axis direction is sealed by a sealing member 321, and the negative end 221 in the Z-axis direction is sealed by a sealing member 322. Furthermore, the ends 271 and 281 of the connecting conduits 270 and 280 are sealed by sealing members 327 and 328, respectively. In this case, the first space 170 is the portion of the first conduit 100 surrounded by the protrusion 410 of the valve 400 and the sealing member 311, and the second space 180 is the portion of the first conduit 100 surrounded by the protrusion 440 of the valve 400 and the sealing member 312.

[0031] As shown in Figure 5, the connecting pipe 270 is connected to the first space 170 of the first pipe 100. The connecting pipe 280 is connected to the groove 160 formed in the first pipe 100, as shown in Figures 5 and 8, and is not connected to the second space 180. In this case, the air pressure in the first space 170 is linked to the air pressure in the suction space 70, which is connected via the second pipe 210. On the other hand, the air pressure in the second space 180 is linked to atmospheric pressure via the atmospheric communication port 190.

[0032] In the first state, the suction system 1 has piping as shown in Figures 5, 6, and 11. Figure 11 is a piping diagram of the suction system in the first state according to the embodiment.

[0033] In this embodiment, the first flow path S1 connecting the first pump 610 and the suction space 70 includes the openings 230 and 240 of the connecting device 10. The second flow path S2 connecting the second pump 620 and the suction space 70 includes the opening 130, the connecting conduit 280, and the portion 136 of the first conduit 100 between the opening 130 and the groove 160. The third flow path S3 connecting the first pump 610 and the second pump 620 includes the openings 120 and 130, and the portion 123 of the first conduit 100 between the openings 120 and 130. The fourth flow path S4 connecting the first pump 610 to the atmosphere includes the openings 120 and 110, and the portion 112 of the first conduit 100 between the openings 120 and 110.

[0034] Valve 400 is pressed in the negative direction on the Z-axis by the coil spring 51 shown in Figure 5. In the first state, the protrusion 430 of valve 400, as shown in Figures 7 and 11, does not block the portion 136 of the first conduit 100 between the opening 130 and the connecting conduit 280, similar to the protrusion 440. Also, the protrusion 420 of valve 400 blocks the portion 123 of the first conduit 100 between the openings 120 and 130, but does not block the portion 112 between the openings 120 and 110.

[0035] In this case, the fourth flow path S4, including section 112, is open and communicates with the atmosphere from the discharge section 612 of the first pump 610. Also, another section 136 of the first pipeline 100 is not blocked by the protrusion 420 or 430 of the valve 400. In this case, the second flow path S2, including section 136, is open and gas is drawn from the suction space 70 to the second pump 620.

[0036] On the other hand, the third flow path S3, which includes section 123, is blocked by the protrusion 420 of the valve 400. As a result, the first pump 610 and the second pump 620 are connected in parallel to the suction space 70.

[0037] In the first state, the end 480 of the valve 400 abuts against the sealing member 312 as shown in Figure 5. In this case, the end face of the convex portion 440 of the valve 400 on the negative side of the Z-axis is in contact with the atmospheric pressure in the second space 180. Also, in the first state, the end face of the shaft portion 450 on the positive side of the Z-axis and the end face of the convex portion 410 on the positive side of the Z-axis are in contact with the gas in the first space 170. The atmospheric pressure of the gas in the first space 170 is approximately the same as the negative pressure in the suction space 70.

[0038] In this case, the force F1 applied to the valve 400 from the positive side of the Z-axis and the force F2 applied from the negative side of the Z-axis are as shown in equations (1) and (2) below.

[0039] F1 = Negative pressure within the suction space 70 × Area of ​​the first end face + Biasing force of the coil spring 50 ... Equation (1)

[0040] F2 = Atmospheric pressure × Area of ​​the second end face ... Equation (2)

[0041] In this embodiment, the area of ​​the first end face is the sum of the area of ​​the end face of the shaft portion 450 (the annular portion located radially outward from the end portion 470), the area of ​​the end face of the convex portion 410 (the annular portion located radially outward from the shaft portion 450), and the area of ​​the end portion 470. The area of ​​the first end face is, for example, the sum of the area of ​​the portion corresponding to D1, the portion corresponding to D3, and the portion corresponding to D4 shown in Figure 7. The area of ​​the second end face is the area of ​​the end face of the convex portion 440 (the annular portion located radially outward from the end portion 480), for example, the area of ​​the portion corresponding to D2 shown in Figure 7. In the first state shown in Figure 5, no force is applied to the end portion 480 that is in contact with the sealing member 312 from the negative direction side of the Z axis, so the area of ​​the end face of the end portion 480 is not included in the area of ​​the second end face used to calculate the force F2. In this case, the area of ​​the first end face is larger than the area of ​​the second end face by an area D4 corresponding to the diameter of the end portion 470. In the first state, the end portion 480 comes into contact with the sealing member 312, which prevents the protrusion 440 from coming into close contact with the sealing member 312.

[0042] Before the first pump 610 and the second pump 620 start operating, the air pressure in the suction space 70 is close to atmospheric pressure. In this case, force F1 > force F2, so valve 400 is in the first state shown in Figure 5.

[0043] When the first pump 610 and the second pump 620 begin suction operation, the air pressure in the first space 171 decreases. When the pressure in the first space 171 falls below a predetermined pressure, the force acting on the valve 400 due to the difference between the atmospheric pressure in the second space 181 and the pressure in the first space 171 exceeds the biasing force of the coil spring 50, so force F1 < force F2, and the valve 400 moves to the positive side of the Z axis. As a result, the end face of the end 480 of the valve 400 separates from the seal member 312, and the atmospheric pressure in the second space 180 is applied to the end face of the end 480. In this state, the force F22 applied to the valve 400 from the negative side of the Z axis is as shown in equation (3) below.

[0044] F22 = F2 + atmospheric pressure × area of the end face of end portion 480 ··· Equation (3)

[0045] That is, since F1 < F2 < F22, the connecting device 10 transitions from the first state shown in FIG. 5 to the second state shown in FIG. 12. FIG. 12 is a cross-sectional view showing an example of the second state of the connecting device in the embodiment. In the following, when expressing that the coil spring 50, the first space 170, and the second space 180 are in the second state, they may be respectively denoted as coil spring 52, first space 172, and second space 182.

[0046] In the second state shown in FIG. 12, the valve 400 is moving in the positive direction on the Z-axis. In this case, the end portion 470 on the positive direction side of the valve 400 on the Z-axis abuts against the seal member 311, while the end portion 480 on the negative direction side of the Z-axis is separated from the seal member 312. As a result, in addition to the area of the second end face in Equation (2), the atmospheric pressure in the second space 182 is also applied to the end face of the end portion 480. Also, the coil spring 52 is being pressed in the positive direction on the Z-axis and is compressed. In the second state, when the end portion 470 abuts against the seal member 311, the contact between the convex portion 410 and the seal member 311 is suppressed.

[0047] In the second state, as shown in FIGS. 12 and 13, as the valve 400 moves, the connection relationship between the first pump 610 and the second pump 620 and the suction space 70 transitions from a parallel connection to a series connection. FIG. 13 is a piping diagram of the second state of the suction system in the embodiment. As shown in FIGS. 12 and 13, the convex portion 420 of the valve 400 moves to a position that closes the portion 112 in the first pipe 100. As a result, the fourth flow path S4 including the portion 112 is blocked, and the third flow path S3 including the portion 123 in the first pipe 100 is released. Also, the convex portion 430 of the valve 400 moves to a position that closes the portion 136 in the first pipe 100. As a result, the second flow path S2 including the portion 136 is blocked.

[0048] In this second state, the discharge section 612 of the first pump 610 shown in Figure 1 is connected to the suction section 621 of the second pump 620 instead of the atmosphere, thereby changing the connection relationship between the first pump 610 and the second pump 620 and the suction space 70 from parallel connection to series connection.

[0049] In the second state, the end portion 470 that contacts the sealing member 311 is not subjected to the air pressure in the first space 172. Therefore, the force F21 applied to the valve 400 from the positive side of the Z-axis in the second state is lower than the force F1 shown in Equation 1 in the first state. The force F21 in the second state is as shown in Equation (4) below.

[0050] F21 = F1 - Negative pressure within the suction space 70 × Area of ​​the end face 470 ... Equation (4)

[0051] In the second state, for example, if the first pump 610 and the second pump 620 stop operating, the air pressure in the first space 172 also rises as the air pressure in the suction space 70 rises. As a result, if F21 > F22, the connecting device 10 returns from the second state shown in Figure 12 to the first state shown in Figure 5.

[0052] As described above, the connection device 10 in the embodiment is connected to the first pump 610, the second pump 620, and the suction space 70. The connection device 10 includes a first flow path S1 connecting the first pump 610 and the suction space 70, a second flow path S2 connecting the second pump 620 and the suction space 70, a third flow path S3 connecting the first pump 610 and the second pump 620, a first pipeline 100 communicating with the second flow path S2 and the third flow path S3, a valve 400, and a first space 170 communicating with the suction space 70. When the air pressure in the first space 170 falls below a predetermined air pressure, the valve 400 opens the third flow path S3 and closes the second flow path S2. With this configuration, the connection state can be switched with a simple configuration without using pressure sensors or solenoid valves, and without accepting other external operations, thus enabling power saving and cost reduction of the connection device 10. Furthermore, since the number of parts can be reduced, the productivity of the connection device 10 can be improved and it can be made smaller.

[0053] Furthermore, in this embodiment, the valve 400 moves between the first position and the second position and does not stop in an intermediate position. As a result, for example, the second flow path S2 and the fourth flow path S4 and the third flow path S3 are not opened or closed simultaneously, thus reducing energy loss when switching between the series state and the parallel state.

[0054] Furthermore, in this embodiment, in both the first and second states, the first flow path S1, which is connected to the second pipeline 200 shown in Figure 6 and includes openings 230 and 240, is not closed. That is, the first flow path S1 remains open regardless of the state of valve 400. With this configuration, even if the suction by the second pump 620 momentarily stops when switching from a parallel state to a series state, the suction operation by the first pump 610 continues without interruption, thus reducing the time lag during switching.

[0055] Furthermore, according to the embodiment, the atmospheric pressure threshold at which the device switches from the first state to the second state can be easily changed by adjusting the area of ​​the first and second end faces of the valve 400 and the strength of the coil spring 50. In this embodiment, atmospheric pressure is assumed to be 101325 Pa.

[0056] For example, in this embodiment, if the minimum negative pressure (first negative pressure) of the pump 600 is -70kPa, a coil spring 50 as shown in Table 1 is used. Note that the change in spring force when the valve 400 moves is approximately 10%.

[0057] [Table 1]

[0058] With this configuration, when the negative pressure in the suction space 70 is higher than -55kPa, the valve 400 is in the first state shown in Figure 5, because the force F1 applied to the valve 400 from the positive side of the Z-axis is greater than the force F2 applied from the negative side of the Z-axis. On the other hand, when the negative pressure falls below -55kPa, the force F1 < force F2, and the valve transitions to the second state shown in Figure 12. This makes it possible to achieve a second negative pressure (for example, -95kPa) that is lower than the first negative pressure. In this case, the predetermined atmospheric pressure (third negative pressure) is -55kPa, which is higher than the first negative pressure. Note that the negative pressure when returning from the second state to the first state may differ from the third negative pressure.

[0059] [Differentiation] The configuration of the embodiment has been described above, but the embodiment is not limited thereto. For example, the biasing member may be a leaf spring, rubber or other elastic material in addition to the coil spring 50, or it may pull the valve 400 in the negative direction along the Z axis instead of pressing it. Furthermore, in order to improve accuracy and response speed, the valve 400 is preferably formed by precision machining of metal, for example, to reduce the gap with the first pipe 100, but it may also be formed from other materials such as resin, depending on the size of the valve, etc.

[0060] Furthermore, in this embodiment, the valve 400 and coil spring 50 are easily positioned in the housing 20 by being inserted into the first conduit 100 in the Z-axis direction, for example, before the sealing members 311 and 312 are attached to the housing 20.

[0061] Furthermore, the housing 20 is not limited to a roughly rectangular parallelepiped shape as shown in Figure 1, but may also be of other shapes such as a roughly cubic shape, a roughly cylindrical shape, or a roughly spherical shape.

[0062] Furthermore, as shown in Figure 14, the formation of recesses such as grooves 811 and 812 on the convex portion 810 of the valve 800 improves the balance of forces in the circumferential direction. Figure 14 is a perspective view showing an example of a modified valve. As shown in Figure 14, in the modified valve 800, the convex portion 810 on which grooves 811 and 812 are formed receives uniform pressure in the circumferential direction, thus improving the balance of forces in the circumferential direction. Similarly, grooves 821 and 822, 831 and 832, and 841 and 842 are formed on the convex portions 820, 830 and 840. Likewise, as shown in Figure 16, grooves 140, 150 and 160 are formed in the first conduit 100 of the housing 900, so that the valve 800 receives uniform pressure in the circumferential direction. With this configuration, the bias of the valve 800 is eliminated and the frictional force between the valve 800 and the first conduit 100 is reduced, so that the valve 800 can move more smoothly. The number of grooves formed on the valve 800 is just an example; each protrusion may have only one groove, or three or more grooves. Similarly, the number of grooves formed on the first conduit 100 is just an example; it may have no grooves at all. Furthermore, instead of grooves, protrusions may be formed on the valve 800 or the first conduit 100. It is desirable that the recesses or protrusions formed on the valve 800 or the first conduit 100 do not hinder the movement of the valve 800 within the first conduit 100, and that, for example, in the second state shown in Figure 12, no gap is created between the opening 110 and the first conduit 100.

[0063] Furthermore, as shown in Figures 15 to 17, the first space 170 may be in direct communication with the suction space 700, rather than via the second conduit 200. Figure 15 is a diagram showing an example of a suction system in a modified example. Figure 16 is a cross-sectional view showing an example of the first state of the connecting device in a modified example. Figure 17 is a piping diagram showing an example of the first state of the suction system in a modified example. Figure 16 shows a cross-section of the connecting device 90 shown in Figure 15, cut along line AA shown in Figure 1.

[0064] As shown in Figure 15, in the modified suction system 9, the suction space 700 further includes a second connection part 701 connected to the opening 991 of the third conduit 990 of the connection device 90, in addition to the first connection part 71 connected to the opening 230 of the connection device 90. Also, as shown in Figure 16, the housing 900 of the connection device 90 in the modified example does not include a second conduit 210 connected to the third conduit 990.

[0065] In the modified example, the force F11 applied to the valve 800 from the positive side of the Z-axis is as shown in equation (11) below.

[0066] F11 = Negative pressure within the suction space 700 × Area of ​​the first end face + Biasing force of the coil spring 50 ... Equation (11)

[0067] When the force F11 shown in equation (11) falls below the force F2 shown in equation (2), the valve 800 moves to the positive side of the Z-axis. As a result, the connection state between the pump 600 and the suction space 700 transitions from the first state to the second state.

[0068] As described above, in the modified connection device 90, the first space 970 of the pump 600 communicates with the suction space 700. With this configuration, the pump 600 can be converted from parallel connection to series connection at a desired third negative pressure with greater precision.

[0069] Although the present invention has been described above based on various embodiments and modifications, it goes without saying that the present invention is not limited to these embodiments and modifications, and that various modifications are possible without departing from the spirit of the invention. Such modifications without departing from the spirit are also included within the technical scope of the present invention, and this will be clear to those skilled in the art from the description of the claims. [Explanation of symbols]

[0070] 1,9 Suction system, 10,90 Connection device, 20,900 Housing, 50 Coil spring, 70,700 Suction space, 100 First conduit, 101,102 End, 110,120,130 Opening, 140,150,160 Groove, 170,970 First space, 180 Second space, 190 Atmospheric communication port, 200,210,220 Second conduit, 211,221 End, 230,240 Opening, 270,280 Connecting conduit, 271,281 End, 311,312,321,322,327,328 Seal member, 400,800 Valve, 410,420,430,440,810,820,830,840 Convex part, 450; Shaft part, 470, 480; End part, 610; First pump, 620; Second pump, 990; Third pipeline, 991; Opening

Claims

1. It is connected to the first pump, the second pump, and the suction space. A first flow path connecting the first pump and the suction space, A second flow path connecting the second pump and the suction space, A third flow path connecting the first pump and the second pump, A first conduit communicating with the second flow path and the third flow path, Valves and A first space communicating with the aforementioned suction space, Equipped with, The valve opens the third passage and closes the second passage when the air pressure in the first space falls below a predetermined air pressure. Connection device.

2. It has a fourth flow path that communicates with the first pump and the first pipeline and connects the first pump to the atmosphere, The valve closes the second and fourth passages when opening the third passage. The connecting device according to claim 1.

3. It has a second space that communicates with the atmosphere, The valve is positioned in the first pipeline and is movably positioned between the first space and the second space. The connecting device according to claim 2.

4. The connecting device according to claim 3, wherein the first space and the second space include a part of the first pipeline and are spaces isolated from the second flow path, the third flow path, or the fourth flow path by a part of the valve.

5. The connecting device according to claim 3, further comprising a biasing member that biases the valve toward the second space.

6. The connecting device according to claim 1 or 2, wherein the valve has a recess or protrusion formed in a direction intersecting the direction of movement of the valve, in the portion facing the first conduit.

7. The connecting device according to claim 1 or 2, wherein the first conduit has a recess or a protrusion formed in a direction intersecting the direction of movement of the valve, in the portion facing the valve.

8. A second pipeline that does not intersect with the first pipeline, A connecting conduit that connects the first conduit and the second conduit, Includes, The first flow path communicates with the second conduit. The connecting device according to claim 1.

9. The connecting device according to claim 8, wherein the first flow path maintains an open state regardless of the state of the valve.

10. The connecting device according to claim 8 or 9, wherein the first space is in communication with the second conduit.

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