JP6078750B2 - Suction system - Google Patents

Description

  The present invention relates to a suction system including a first suction device and a second suction device and configured to be able to suck gas from a suction target by switching both suction devices to either a parallel connection state or a serial connection state. It is.

  As a suction system of this type, a vacuum exhaust device is disclosed in Patent Document 1 below. This vacuum evacuation device includes a pair of vacuum pumps 1a and 1b and three valves 2a to 2c for switching both vacuum pumps 1a and 1b to either a parallel connection state or a serial connection state. It is configured so that air can be exhausted (sucked) from the subject. In the following description, the two vacuum pumps 1a and 1b in Patent Document 1 are distinguished from each other in order to distinguish them from the constituent elements of the suction systems 1 and 1A described in the “DETAILED DESCRIPTION OF THE INVENTION”. When the “vacuum pump 1a” is referred to as the “first vacuum pump”, the “vacuum pump 1b” is referred to as the “second vacuum pump”, and the valves 2a to 2c are distinguished from each other, The “valve 2a” is referred to as “first valve”, the “valve 2b” is referred to as “second valve”, and the “valve 2c” is referred to as “third valve”.

  In this vacuum evacuation device, first, the first valve and the third valve are opened, and the second valve is closed to switch the first vacuum pump and the second vacuum pump to the parallel connection state. Make it work. At this time, the suction port of the second vacuum pump is connected to the exhaust target by opening the first valve, and air is sucked from the exhaust target by both vacuum pumps. Further, by closing the second valve and opening the third valve, the discharge port of the first vacuum pump is communicated with the exhaust destination without being communicated with the suction port of the second pump. The sucked air is exhausted toward the exhaust destination. As a result, the vacuum pressure in the pipe connecting the exhaust target and the vacuum exhaust device gradually increases.

  On the other hand, when the vacuum pressure in the pipe reaches the specified pressure (when the vacuum pressure in the pipe is high enough to make it difficult to suck air when connected in parallel), both vacuum pumps The first vacuum pump and the second vacuum pump are switched to the serial connection state by closing the first valve and the third valve and opening the second valve while maintaining the state in which is operated. At this time, the first valve is closed and the second valve is opened, whereby the suction port of the second vacuum pump is connected to the discharge port of the first vacuum pump. In addition, when the third valve is closed, the discharge port of the first vacuum pump is disconnected from the exhaust destination, and the air discharged from the first vacuum pump is sucked by the second pump and exhausted to the exhaust destination. Become.

  In this series connection state, since the air discharged from the discharge port of the first vacuum pump is sucked by the second vacuum pump, the resistance (exhaust resistance) generated when the air is discharged from the first vacuum pump is reduced. 1 The suction efficiency of the vacuum pump is improved. As a result, even if the vacuum pressure in the piping is somewhat high due to the operation in the parallel connection state, it is possible to suck more air from the exhaust target by both vacuum pumps switched to the serial connection state. The vacuum pressure in the pipe rises to a sufficiently high vacuum pressure than when operating in a state.

Japanese Utility Model Publication No. 4-119373 (page 3-5, Fig. 1-3)

  However, the conventional vacuum exhaust apparatus has the following problems to be solved. That is, in the conventional evacuation apparatus, the first vacuum pump and the second vacuum pump are switched between the parallel connection state and the series connection state by changing the open / close state of the first valve, the second valve, and the third valve. Configuration is adopted. In this case, although the above-described Patent Document 1 does not clearly indicate the opening / closing order of the valves, for example, when the two vacuum pumps are switched to the serial connection state, the third valve is opened prior to opening the second valve. When closed (when the third valve is closed earlier than the second valve is opened), a so-called cutoff operation occurs in the first pump, and there is no destination for the air discharged from the first pump. It becomes a state. In such a state, a great burden is placed on the first pump, and when the time for the cutoff operation is long (when the time from closing the third valve to opening the second valve is long), the first pump breaks down. There is a problem of fear.

  Further, in this type of vacuum exhaust apparatus, for example, when a large amount of air is sucked from the exhaust target, the vacuum pressure in the pipe connecting the exhaust target and the vacuum exhaust apparatus is large. May decrease. When such a state is reached, it is necessary to increase the vacuum pressure in the pipe in a short time by switching both vacuum pumps operating in the series connection state to the parallel connection state. In this case, the above-mentioned Patent Document 1 does not clearly indicate switching from the serial connection state to the parallel connection state, but when switching to the parallel connection state, for example, the second valve prior to opening the third valve. Is closed (when the second valve is closed earlier than the third valve is opened), the cutoff operation occurs in the first pump, and there is no destination for the air discharged from the first pump. It becomes. Even in such a state, the first pump is heavily loaded, and when the time for the cutoff operation is long (when the time from closing the second valve to opening the third valve is long), the first pump fails. There is a problem of fear.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a suction system capable of avoiding a failure of the suction device.

In order to achieve the above object, the suction system according to claim 1 includes a first suction device and a second suction device, and is configured to be able to suck a gas from a suction target by the both suction devices. Connected in parallel to the suction target, the suction port of the first suction device is connected to the suction target, and the suction port of the second suction device is connected to the suction target of the first suction device. A suction system configured to be switchable to any one of a series connection state connected to an outlet, wherein the control unit switches and controls the suction devices to either the parallel connection state or the series connection state; A first connection pipe for connecting the suction port of the first suction device to the suction target, a second connection pipe for connecting the suction port of the second suction device to the suction target, and the second connection A first on-off valve arranged in a pipe, a discharge pipe connected to the discharge port of the first suction device, a second on-off valve arranged in the discharge pipe, and the discharge pipe One end portion is connected between the end portion on the first suction device side and the portion where the second on-off valve is disposed, and the end portion on the second suction device side in the second connection pipe and the first A third connection pipe having the other end connected between the arrangement parts of the on-off valve, and a third on-off valve arranged in the third connection pipe, wherein the first on-off valve, The two on-off valves and the third on-off valve are respectively configured by electromagnetic valves that are controlled to be opened and closed by the control unit, and the control unit controls the first on-off valve to close and controls the second connection pipe. The movement of the gas from the connection part of the third connection pipe toward the suction target is regulated, To, after allowing the movement of gas towards the second connecting pipe from the discharge pipe by opening controls the third on-off valve, the discharge pipe by closing controlling said second on-off valve The movement of the gas from the outside toward the end on the first suction device side is regulated to switch the suction devices to the serial connection state.

Aspiration system of claim 2, wherein, in the aspiration system of claim 1, further comprising a pressure sensor for detecting the vacuum pressure in said first connection pipe, wherein, based on the sensor signal from the pressure sensor The vacuum pressure in the first connection pipe is specified, and when the specified vacuum pressure exceeds a predetermined first vacuum pressure, the closing control of the first on-off valve, the third on-off valve And the closing control of the second on-off valve is performed to switch the suction devices to the serial connection state. Note that “when the first vacuum pressure is exceeded” includes not only “the moment when the first vacuum pressure is exceeded” but also “a few seconds (a slight time) defined in advance after the first vacuum pressure is exceeded. ) (When the vacuum pressure at this time has passed) or “when a predetermined time (slight time) has passed since the first vacuum pressure was exceeded” This includes “when the state exceeding the vacuum pressure is maintained”.

The suction system according to claim 3 includes a first suction device and a second suction device, and is configured to be able to suck gas from the suction target by the suction devices, and the suction port of the suction devices is the suction target. And a serial connection state in which the suction port of the first suction device is connected to the suction target and the suction port of the second suction device is connected to the discharge port of the first suction device. A control unit configured to switch the suction devices to either the parallel connection state or the serial connection state, and the suction of the first suction device. A first connection pipe for connecting a mouth to the suction target, a second connection pipe for connecting the suction port of the second suction device to the suction target, and a second connection pipe disposed on the second connection pipe. 1 open A valve, a discharge pipe connected to the discharge port of the first suction device, a second on-off valve disposed in the discharge pipe, and an end of the discharge pipe on the first suction device side And one end of the second on-off valve is disposed between the end of the second connection pipe on the second suction device side and the disposition of the first on-off valve. A third connecting pipe having the other end connected thereto; and a third on-off valve disposed in the third connecting pipe, wherein the first on-off valve is connected from the suction target to the second suction device. consists of a check valve for regulating the movement from the connection portion of the third connection pipe of the gas towards the said aspiration object in the second connecting pipe as well as permit movement of gas towards the second on-off valve and the The third on-off valve is an electromagnetic valve that is controlled to open and close by the control unit. The controller is configured to control the closing of the second on-off valve after allowing the gas to move from the discharge pipe to the second connection pipe by controlling the opening of the third on-off valve. Then, the movement of the gas from the outside of the discharge pipe toward the end on the first suction device side is regulated to switch the two suction devices to the serial connection state .

A suction system according to a fourth aspect of the present invention is the suction system according to the third aspect , further comprising a pressure sensor that detects a vacuum pressure in the first connection pipe, and the control unit is based on a sensor signal from the pressure sensor. The vacuum pressure in the first connection pipe is specified, and when the specified vacuum pressure exceeds a predetermined first vacuum pressure, the opening control of the third on-off valve and the second opening / closing Valve closing control is performed to switch the suction devices to the serial connection state.

The suction system according to claim 5 includes a first suction device and a second suction device, and is configured to be able to suck a gas from a suction target by the suction devices, and the suction port of the suction devices is the suction target. And a serial connection state in which the suction port of the first suction device is connected to the suction target and the suction port of the second suction device is connected to the discharge port of the first suction device. A control unit configured to switch the suction devices to either the parallel connection state or the serial connection state, and the suction of the first suction device. A first connection pipe for connecting a mouth to the suction target, a second connection pipe for connecting the suction port of the second suction device to the suction target, and a second connection pipe disposed on the second connection pipe. 1 open A valve, a discharge pipe connected to the discharge port of the first suction device, a second on-off valve disposed in the discharge pipe, and an end of the discharge pipe on the first suction device side And one end of the second on-off valve is disposed between the end of the second connection pipe on the second suction device side and the disposition of the first on-off valve. A third connection pipe having the other end connected thereto; and a third on-off valve disposed in the third connection pipe, the first on-off valve, the second on-off valve, and the third on-off valve. Are each configured by an electromagnetic valve that is controlled to be opened and closed by the control unit, and the control unit controls the opening of the second on-off valve so that the end from the first suction device side is connected to the outside of the discharge pipe. After allowing the movement of the gas to go, the exhaust is controlled by closing the third on-off valve To restrict the movement of gas towards the second connecting pipe from the pipe, then, to permit movement of gas towards the second suction device from said aspirated by opening controls the first on-off valve wherein Both suction devices are switched to the parallel connection state.

A suction system according to a sixth aspect is the suction system according to the fifth aspect , further comprising a pressure sensor that detects a vacuum pressure in the first connection pipe, and the control unit is based on a sensor signal from the pressure sensor. The vacuum pressure in the first connection pipe is specified, and when the specified vacuum pressure falls below a predetermined second vacuum pressure, the opening control of the second on-off valve, the third on-off valve And the opening control of the first on-off valve is performed to switch the suction devices to the parallel connection state. Note that “when the pressure falls below the second vacuum pressure” includes not only “the moment when the pressure falls below the second vacuum pressure”, but also “a time of a few seconds (a slight time) defined in advance after the pressure falls below the second vacuum pressure”. ) (When the vacuum pressure at this time is reached) or “when a predetermined time of about a few seconds (slight time) has passed after falling below the second vacuum pressure” This includes “when the state below the vacuum pressure is maintained”.

The suction system according to claim 7 includes a first suction device and a second suction device, and is configured to be able to suck a gas from a suction target by the suction devices, and the suction port of the suction devices is the suction target. And a serial connection state in which the suction port of the first suction device is connected to the suction target and the suction port of the second suction device is connected to the discharge port of the first suction device. A control unit configured to switch the suction devices to either the parallel connection state or the serial connection state, and the suction of the first suction device. A first connection pipe for connecting a mouth to the suction target, a second connection pipe for connecting the suction port of the second suction device to the suction target, and a second connection pipe disposed on the second connection pipe. 1 open A valve, a discharge pipe connected to the discharge port of the first suction device, a second on-off valve disposed in the discharge pipe, and an end of the discharge pipe on the first suction device side And one end of the second on-off valve is disposed between the end of the second connection pipe on the second suction device side and the disposition of the first on-off valve. A third connecting pipe having the other end connected thereto; and a third on-off valve disposed in the third connecting pipe, wherein the first on-off valve is connected from the suction target to the second suction device. consists of a check valve for regulating the movement from the connection portion of the third connection pipe of the gas towards the said aspiration object in the second connecting pipe as well as permit movement of gas towards the second on-off valve and the The third on-off valve is an electromagnetic valve that is controlled to open and close by the control unit. The control unit is configured to control the opening of the second on-off valve to permit the movement of gas from the end on the first suction device side toward the outside of the discharge pipe, and then to control the third on-off valve. Is controlled to block the movement of the gas from the discharge pipe to the second connection pipe, and the two suction devices are switched to the parallel connection state .

The suction system according to claim 8 is the suction system according to claim 7 , further comprising a pressure sensor for detecting a vacuum pressure in the first connection pipe, wherein the control unit is based on a sensor signal from the pressure sensor. The vacuum pressure in the first connection pipe is specified, and when the specified vacuum pressure falls below a predetermined second vacuum pressure, the opening control of the second on-off valve and the third opening / closing Valve closing control is performed to switch the suction devices to the parallel connection state.

According to the suction system of claims 1 and 3 , after the control section allows the gas to move from the discharge pipe to the second connection pipe by controlling the opening of the third on-off valve, the second on-off valve By controlling the gas from the outside of the discharge pipe to the end of the first suction device by switching the suction device to a serially connected state, thereby controlling the opening of the third on-off valve. As a result, it is possible to avoid a situation in which the movement of the air from the discharge port of the first suction device to the outside of the discharge pipe is restricted, so that a situation in which the first suction device causes a cutoff operation when switching to the serial connection state is avoided. Can do. Thereby, since the situation where a big burden is applied to the first suction device can be avoided, the failure of the first suction device can be preferably avoided.

Further, according to the suction system of claim 1, wherein the control unit, of a gas toward the suction target from the connecting portion of the piping the third connection in a second pipe connection by closing controlling the first on-off valve After restricting the movement, the opening control of the third on-off valve and the closing control of the second on-off valve are performed to switch both suction devices to the serial connection state. The air discharged from the discharge port of the suction device to the discharge pipe and flowing into the second connection pipe via the third connection pipe does not move toward the suction target. The situation where the supplied vacuum pressure falls can be avoided suitably.

Furthermore, according to the suction system of the second aspect , when the vacuum pressure in the first connection pipe specified by the control unit based on the sensor signal from the pressure sensor exceeds the first vacuum pressure, the first The suction devices are automatically controlled according to the state of the suction target by switching the suction devices to the serial connection state by performing the closing control of the on-off valve, the opening control of the third on-off valve, and the closing control of the second on-off valve. Therefore, a sufficient amount of air can be reliably sucked from the suction target under a sufficiently high vacuum pressure required for the suction target.

According to the suction system of the third aspect, the movement of the gas from the suction target to the second suction device is allowed and the gas flowing from the connection part of the third connection pipe in the second connection pipe to the suction target is allowed. Since the first on-off valve is configured by a check valve that restricts movement, the opening of the third on-off valve is controlled when switching to the serial connection state, and the air discharged from the discharge port of the first suction device to the discharge pipe Flows into the second connection pipe through the third connection pipe, the first on-off valve is automatically switched to the closed state, and the suction target from the connection portion of the third connection pipe in the second connection pipe Since the movement of the air toward is restricted, the situation in which the vacuum pressure supplied to the suction target decreases when switching to the serial connection state can be suitably avoided. In addition, since one of the plurality of on-off valves necessary for switching to the serial connection state is configured with an inexpensive on-off valve, the manufacturing cost of the suction system can be sufficiently reduced.

Furthermore, according to the suction system of the fourth aspect , when the vacuum pressure in the first connection pipe specified by the control unit based on the sensor signal from the pressure sensor exceeds the first vacuum pressure, the third By performing opening control of the on-off valve and closing control of the second on-off valve and switching both suction devices to the serial connection state, both suction devices can be automatically switched to the serial connection state according to the state of the suction target. Therefore, it is possible to reliably suck a sufficient amount of air from the suction target under a sufficiently high vacuum pressure required for the suction target.

According to the suction system of claims 5 and 7 , after the control unit allows the movement of the gas from the end on the first suction device side to the outside of the discharge pipe by opening control of the second on-off valve. By controlling the closing of the third on-off valve to restrict the movement of gas from the discharge pipe to the second connection pipe and switching both suction devices to the parallel connection state, from the end on the first suction device side Since the movement of the air from the discharge pipe to the second connection pipe is restricted after the movement of the air toward the outside of the discharge pipe is permitted, the first suction device is switched when switching to the parallel connection state Thus, it is possible to suitably avoid a situation in which a deadline operation occurs. Thereby, since the situation where a big burden is applied to the first suction device can be avoided, the failure of the first suction device can be preferably avoided.

According to the suction system of the fifth aspect , the control unit performs the opening control of the second on-off valve and the closing control of the third on-off valve, and then performs the opening control of the first on-off valve, thereby subjecting to suction. The movement of the air from the discharge pipe to the second connection pipe is restricted by allowing the movement of the gas from the exhaust pipe to the second suction apparatus and switching both suction apparatuses to the parallel connection state. The opening and closing of the 1 on-off valve causes the air that has been discharged from the discharge port of the first suction device to the discharge pipe and flows into the second connection pipe through the third connection pipe toward the suction target. Since it does not move, a situation in which the vacuum pressure supplied to the suction target is reduced when switching to the parallel connection state can be suitably avoided.

Further, according to the suction system of the sixth aspect , when the vacuum pressure in the first connection pipe specified by the control unit based on the sensor signal from the pressure sensor falls below the second vacuum pressure, the second The suction devices are automatically controlled according to the state of the suction target by performing the opening control of the on-off valve, the closing control of the third on-off valve, and the opening control of the first on-off valve to switch both suction devices to the parallel connection state. Therefore, it is possible to reliably suck a sufficient amount of air from the suction target under a sufficiently high vacuum pressure required for the suction target.

According to the suction system of the seventh aspect, the movement of the gas from the suction target to the second suction device is allowed and the gas from the connection portion of the third connection pipe in the second connection pipe to the suction target is allowed. By configuring the first on-off valve with a check valve that restricts movement, the third on-off valve is controlled to be closed when switching to the parallel connection state, and movement of air from the discharge pipe to the second connection pipe is restricted. In this state, when the vacuum pressure in the second connection pipe is sufficiently increased by the suction of air in the second connection pipe by the second suction device, the first on-off valve is automatically switched to the open state. Since the movement of air from the suction target to the second suction device is allowed, a situation in which the vacuum pressure supplied to the suction target is reduced when switching to the parallel connection state can be suitably avoided. In addition, since one of the plurality of on-off valves necessary for switching to the parallel connection state is configured with an inexpensive on-off valve, the manufacturing cost of the suction system can be sufficiently reduced.

Furthermore, according to the suction system of the eighth aspect , when the vacuum pressure in the first connection pipe specified by the control unit based on the sensor signal from the pressure sensor falls below the second vacuum pressure, the second By performing opening control of the on-off valve and closing control of the third on-off valve to switch both suction devices to the parallel connection state, both suction devices can be automatically switched to the parallel connection state according to the state of the suction target. Therefore, it is possible to reliably suck a sufficient amount of air from the suction target under a sufficiently high vacuum pressure required for the suction target.

  In the present specification, “pressure lower than atmospheric pressure (negative pressure)” is referred to as “vacuum pressure”, and “pressure above atmospheric pressure (positive pressure)” is simply referred to as “pressure”. In addition, a state in which the vacuum pressure is close to absolute vacuum is referred to as “high vacuum pressure (high vacuum state)”, and a state in which the vacuum pressure is close to atmospheric pressure is referred to as “low vacuum pressure (low vacuum). State) ”, changing from a vacuum pressure close to atmospheric pressure to a vacuum pressure close to absolute vacuum is called“ vacuum pressure rises ”, and changes from a vacuum pressure close to absolute vacuum to a vacuum pressure close to atmospheric pressure. This is called "vacuum pressure decreases".

It is a lineblock diagram showing the composition of suction system 1 concerning an embodiment of the invention. It is a block diagram which shows the structure of 1 A of suction systems which concern on other embodiment of this invention.

  Hereinafter, embodiments of a suction system will be described with reference to the accompanying drawings.

  First, the configuration of the suction system 1 will be described with reference to the attached drawings.

  A suction system 1 shown in FIG. 1 is an example of a “suction system”, and includes vacuum pumps 2a and 2b, an inverter circuit 2c, a pressure sensor 3, and a control unit 4, and includes an injection molding machine, a suction holding device, and a vacuum packaging machine. In addition, air (an example of “gas”) is sucked by vacuum pumps 2a and 2b from various suction targets such as tools for degassing air in various containers such as boxes and bags (vacuum is applied to the suction target). Pressure supply).

  Specifically, in the suction system 1, the suction port of the vacuum pump 2a is connected to the suction target via the pipes P1a and P1, and the suction port of the vacuum pump 2b is connected to the suction target via the pipes P1b and P1. It is connected. The pipe P1a has a check valve CV1 (ball type, disk type, which allows movement of air from the pipe P1 side (suction target side) toward the vacuum pump 2a and restricts movement of air in the reverse direction. And a mechanical one-way valve such as a swing type: as an example, a ball check valve is provided, and the pipe P1b allows air to move from the pipe P1 side (the suction target side) toward the vacuum pump 2b, In addition, a check valve (for example, a ball check valve) CV2 that restricts air movement in the reverse direction is provided. Thereby, in this suction system 1, even when the vacuum pumps 2a and 2b are stopped, it is possible to prevent the vacuum pressure in the pipe P1 from decreasing for a certain period of time. In addition, when it is not necessary to maintain the vacuum pressure in the piping P1 when the vacuum pumps 2a and 2b are stopped, the check valves CV1 and CV2 can be omitted. Further, an electromagnetic valve SV2 that opens or closes the pipe P1b according to the control of the control unit 4 is disposed in the pipe P1b.

  In the suction system 1, the discharge port of the vacuum pump 2a is opened to the atmosphere via the pipe P2a, and the discharge port of the vacuum pump 2b is opened to the atmosphere via the pipe P2b. Furthermore, an electromagnetic valve SV3 that opens or closes the pipe P2a according to the control of the control unit 4 is disposed in the pipe P2a. In the suction system 1, one end is connected between the end of the pipe P2a on the side of the vacuum pump 2a and the portion where the electromagnetic valve SV3 is disposed, and the end of the pipe P1b on the side of the vacuum pump 2b. And a pipe P3 having the other end connected between the solenoid valve SV2 and the portion where the solenoid valve SV2 is disposed. Further, an electromagnetic valve SV1 that opens or closes the pipe P3 according to the control of the control unit 4 is disposed in the pipe P3.

  In this case, the solenoid valve SV1 permits air movement from the pipe P2a to the pipe P1b (that is, air movement from the discharge port of the vacuum pump 2a to the suction port of the vacuum pump 2b) in a state in which the opening is controlled. The movement of air from the pipe P2a to the pipe P1b is regulated in a state in which the closing control is performed. The solenoid valve SV2 allows air to move from the pipe P1 side (at the suction target side) to the vacuum pump 2b in a state in which the opening is controlled, and from the pipe P1 side to the vacuum pump 2b in a state in which the opening is controlled. The movement of air and the movement of air from the connection part of the pipe P3 in the pipe P1b toward the pipe P1 side are restricted.

  Further, the electromagnetic valve SV3 allows air movement (discharge to the atmosphere) from the discharge port of the vacuum pump 2a to the outside of the pipe P2a in the state in which the opening is controlled, and in the state in which the vacuum pump 2a is controlled in the closed state. The movement of air from the discharge port toward the outside of the pipe P2a and the movement of air from the outside of the pipe P2a toward the discharge port of the vacuum pump 2a (intrusion of air from the pipe P2a) are restricted. Thereby, in this suction system 1, as will be described later, the electromagnetic valve SV3 is opened, the electromagnetic valve SV1 is closed, and the electromagnetic valve SV2 is opened, so that the vacuum pump is applied to the suction target. 2a and 2b are connected in parallel (parallel connection state), the electromagnetic valve SV2 is closed, the electromagnetic valve SV1 is opened, and the electromagnetic valve SV3 is closed, thereby vacuuming the suction target. The pumps 2a and 2b can be switched to either a state in which the pumps 2a and 2b are connected in series (series connection state).

  In the suction system 1 of this example, the pipes P1 and P1a are combined to correspond to the “first connection pipe”, and the pipes P1 and P1b are combined to correspond to the “second connection pipe”. . In this example, the pipe P2a corresponds to the “discharge pipe” and the pipe P3 corresponds to the “third connection pipe”. Further, in this example, the electromagnetic valve SV2 disposed in the pipe P1b corresponds to a “first on-off valve”, and the electromagnetic valve SV3 disposed in the pipe P2a corresponds to a “second on-off valve”. The electromagnetic valve SV1 disposed in the pipe P3 corresponds to a “third on-off valve”.

  The vacuum pumps 2a and 2b are configured to include, as a power source, a motor that rotates at a rotational speed (rotational speed) corresponding to the frequency of the electric power supplied from the inverter circuit 2c. In this case, in this example, as an example, the vacuum pump 2a corresponds to a “first suction device”, and the vacuum pump 2b corresponds to a “second suction device”. Moreover, in the suction system 1 of this example, as an example, both vacuum pumps 2a and 2b are configured by a vacuum pump having the same suction capability per rotation speed (a vacuum pump having the same processing capability).

  The inverter circuit 2c constitutes a “control unit” in combination with the control unit 4, and changes the frequency of the power supplied to the vacuum pumps 2a and 2b according to the control of the control unit 4, thereby enabling the vacuum pumps 2a and 2b. Operate at an arbitrary rotational speed (controls the rotational speeds of the vacuum pumps 2a and 2b). As an example, the pressure sensor 3 is disposed in the pipe P1 described above, and the vacuum pressure in the pipe P1 when the air is sucked by the vacuum pumps 2a and 2b (“the vacuum pressure in the first connection pipe”). A sensor signal that can specify one example) is output.

  As described above, the control unit 4 constitutes a “control unit” in combination with the inverter circuit 2c, and controls the suction system 1 as a whole. Specifically, the control unit 4 calculates the vacuum pressure in the pipe P <b> 1 based on the sensor signal from the pressure sensor 3. Further, the control unit 4 controls the electromagnetic valves SV1 to SV3 to either the open state or the closed state in accordance with the calculated vacuum pressure in the pipe P1 or the operating state of the suction system 1, whereby both vacuum pumps 2a, 2b is switched to either a parallel connection state or a series connection state (execution of switching control). Further, the control unit 4 operates the vacuum pumps 2a and 2b by controlling the inverter circuit 2c to supply power to both the vacuum pumps 2a and 2b.

  Next, suction processing (vacuum pressure supply processing) for sucking air from the suction target by the suction system 1 will be described with reference to the accompanying drawings.

  In this suction system 1, when a start switch of an operation unit (not shown) is operated, the control unit 4 controls the electromagnetic valve SV1 to a closed state and controls the electromagnetic valves SV2 and SV3 to an open state, and an inverter The circuit 2c is controlled to start operation of both vacuum pumps 2a and 2b. At this time, the movement of the air from the pipe P2a to the pipe P1b is restricted by the closing control of the electromagnetic valve SV1, and the air from the pipe P1 (suction target) to the suction port of the vacuum pump 2b by the opening control of the electromagnetic valve SV2. The flow of air is allowed, and the flow of air from the discharge port of the vacuum pump 2a to the outside of the pipe P2a (opening of air from the vacuum pump 2a) is allowed by opening control of the electromagnetic valve SV3, so that both vacuum pumps 2a , 2b are connected in parallel. Further, the supply of electric power from the inverter circuit 2c causes the vacuum pump 2a to start sucking air in the pipe P1a, and the vacuum pump 2b starts to suck air in the pipe P1b.

  In this case, at the start of operation of the vacuum pumps 2a and 2b, the insides of the pipes P1, P1a, P1b, P2a, P2b, and P3 are at atmospheric pressure. Therefore, when the air in the pipe P1a is sucked by the vacuum pump 2a, the check valve CV1 is opened, and movement of air from the suction target toward the vacuum pump 2a is allowed, and the pipe P1b is allowed by the vacuum pump 2b. When the air inside is sucked, the check valve CV2 is opened and air movement from the suction target to the vacuum pump 2b through the electromagnetic valve SV2 is allowed. As a result, air is sucked from the suction target by the vacuum pump 2a through the pipes P1 and P1a, and air is sucked from the suction target by the vacuum pump 2b through the pipes P1 and P1b. Thereby, the inside of the pipes P1, P1a, P1b is in a vacuum state, and the vacuum pressure gradually increases according to the elapsed time from the start of operation of the vacuum pumps 2a, 2b.

  Further, the air sucked into the vacuum pump 2a through the pipes P1 and P1a is discharged from the discharge port to the pipe P2a. At this time, the solenoid valve SV1 arranged in the pipe P3 connected to the pipe P2a is controlled to be closed, and the ingress of air from the pipe P2a to the pipe P3 is restricted, but is arranged in the pipe P2a. Since the opening of the solenoid valve SV3 is controlled and the flow of air from the vacuum pump 2a to the outside of the pipe P2a is allowed, the vacuum pump 2a is discharged from the vacuum pump 2a to the pipe P2a without causing a cutoff operation. The discharged air passes through the electromagnetic valve SV3 and is released into the atmosphere. Further, the air sucked into the vacuum pump 2b through the pipes P1 and P1b is released from the discharge port into the atmosphere through the pipe P2b.

  On the other hand, the control unit 4 performs the closing control of the electromagnetic valve SV1, the opening control of the electromagnetic valves SV2 and SV3, and the power supply control from the inverter circuit 2c, and at the same time, the sensor output from the pressure sensor 3 Calculation (specification) of the vacuum pressure in the pipe P1 based on the signal is started. In addition, the control unit 4 exceeds 93.0 kPa when a predetermined time of several seconds elapses after the calculated vacuum pressure exceeds 93.0 kPa (an example of “first vacuum pressure”) as an example. When the closed state is maintained (an example of “when exceeding the first vacuum pressure”), the solenoid valve SV1 is closed and controlled while the operations of both vacuum pumps 2a and 2b are continued. Both the vacuum pumps 2a and 2b are switched to a serial connection state by controlling the opening and then closing the solenoid valve SV3. In addition, as the above “first vacuum pressure”, the amount of air sucked per unit time (the amount of increase in vacuum pressure per unit time) is switched to the series connection state rather than continuing the operation in the parallel connection state. What is necessary is just to prescribe | regulate the vacuum pressure which increases.

  At this time, the solenoid valve SV2 is controlled to be closed, so that the air moves from the pipe P1 (subject of suction) to the vacuum pump 2b via the pipe P1b, and from the connection part of the pipe P3 in the pipe P1b to the pipe P1 ( The movement of air toward the suction target) is restricted. Further, the opening of the electromagnetic valve SV1 is controlled so that the pipe P2a connected to the discharge port of the vacuum pump 2a and the pipe P1b connected to the suction port of the vacuum pump 2b communicate with each other via the pipe P3. As a result, the movement of air from the pipe P2a to the pipe P1b is allowed, and the discharge port of the vacuum pump 2a and the suction port of the vacuum pump 2b are connected to each other. Furthermore, by closing control of the solenoid valve SV3, entry of air into the pipe P2a and release of air discharged from the vacuum pump 2a into the pipe P2a are restricted. Thereby, both vacuum pumps 2a and 2b are switched to a serial connection state, and air from the suction target is sucked by the vacuum pump 2a, and air discharged from the vacuum pump 2a to the pipe P2a passes through the pipes P3 and P1b. It is sucked by the vacuum pump 2b and released to the atmosphere via the pipe P2b.

  Further, when both the vacuum pumps 2a and 2b are switched to the serial connection state, since the air discharged from the vacuum pump 2a is sucked by the vacuum pump 2b, the vacuum resistance is reduced by the amount that the exhaust resistance of the vacuum pump 2a is reduced. The suction efficiency of the pump 2a is improved. Therefore, by continuing the suction of air by both vacuum pumps 2a and 2b in the serial connection state, suction is performed even in a state where the vacuum pressure in the pipes P1a and P1 is higher than the vacuum pressure that can be reached in the parallel connection state. It becomes possible to suck air from the object. Thereby, the vacuum pressure in the pipes P1a and P1 further increases, and air is sucked from the suction target under a sufficiently high vacuum pressure required for the suction target.

  In this case, as described above, when the two vacuum pumps are switched to the serial connection state in the conventional evacuation apparatus, when the third valve is closed before the second valve is opened, the cutoff operation is performed in the first pump. If this occurs, a large burden is placed on the first pump, and when the time for the cutoff operation is long, the first pump may break down. On the other hand, in the suction system 1 of this example that controls the closing of the electromagnetic valve SV3 after the opening of the electromagnetic valve SV1 when the control unit 4 switches both vacuum pumps 2a and 2b to the serial connection state, the vacuum pump 2a Since the release of the atmosphere is restricted after the air discharged from the air is sucked by the vacuum pump 2b, a situation in which a cutoff operation occurs in the vacuum pump 2a is preferably avoided.

  Further, when the two vacuum pumps are switched to the serial connection state in the conventional evacuation device, when the second valve is opened prior to closing the first valve, the suction ports of both the vacuum pumps are evacuated (suction object). ) The air discharged from the first pump flows into the pipe for connecting to the pipe, and the vacuum pressure in the pipe connected to the exhaust target (suction target) may decrease due to this. . On the other hand, in the suction system 1 of this example that controls the opening of the electromagnetic valve SV1 after closing the electromagnetic valve SV2 when switching to the serial connection state, the vacuum pump 2a is connected to the pipe P1b via the pipes P2a and P3. Since the air that has moved inward does not flow into the pipe P1, a situation in which the degree of vacuum in the pipe P1 decreases is also suitably avoided.

  On the other hand, for example, when the state of the suction target changes and a large amount of air is sucked from the suction target per unit time (a state where the load on the suction system 1 is increased), in the serial connection state, from the suction target It may be difficult to suck air sufficiently, and the vacuum pressure in the pipe P1 may gradually decrease. Therefore, the control unit 4 has a vacuum pressure of 93.0 kPa (an example of “second vacuum pressure”) as an example based on the sensor signal output from the pressure sensor 3 during operation in a serial connection state. The vacuum pump 2a is in a state where a state of less than 93.0 kPa is maintained at the time when a predetermined time of about several seconds has passed since the pressure is less than (a case when the pressure is less than the second vacuum pressure). , 2b, while controlling the opening of the solenoid valve SV3, the solenoid valve SV1 is controlled to close, and then the opening of the solenoid valve SV2 is controlled to switch both vacuum pumps 2a, 2b to the parallel connection state. In addition, as the “second vacuum pressure”, the amount of air sucked per unit time (the amount of increase in vacuum pressure per unit time) is switched to the parallel connection state rather than continuing the operation in the series connection state. When the vacuum pressure increases, that is, when switching from the serial connection state to the parallel connection state, the time required to increase to the vacuum pressure required for the suction target is shortened (short time to the required vacuum pressure) The vacuum pressure can be specified.

  At this time, the flow of air from the discharge port of the vacuum pump 2a toward the outside of the pipe P2a is permitted by controlling the opening of the electromagnetic valve SV3. Further, the movement of air from the pipe P2a to the pipe P1b is restricted by closing control of the electromagnetic valve SV1. Further, the opening of the solenoid valve SV2 allows the air flow from the pipe P1 (suction target) to the vacuum pump 2b. Thereby, both vacuum pumps 2a and 2b are switched to a parallel connection state, air is sucked from the suction target by the vacuum pump 2a via the pipes P1 and P1a, and from the suction target by the vacuum pump 2b via the pipes P1 and P1b. Air is sucked, and air sucked by the vacuum pump 2a is discharged to the pipe P2a and released to the atmosphere, and air sucked by the vacuum pump 2b is discharged to the pipe P2b and opened to the atmosphere. Therefore, the amount of air sucked per unit time is increased as compared to when both vacuum pumps 2a and 2b are operated in a series connection state, and as a result, the inside of the pipe P1 is larger than when the operation in the series connection state is continued. The vacuum pressure rises in a short time. As a result, air can be sucked from the suction target under a sufficiently high vacuum pressure required for the suction target in a relatively short time.

  In this case, as described above, when the two vacuum pumps are switched to the parallel connection state in the conventional evacuation apparatus, when the second valve is closed before the third valve is opened, the cutoff operation is performed in the first pump. If this occurs, a large burden is placed on the first pump, and when the time for the cutoff operation is long, the first pump may break down. On the other hand, in the suction system 1 of this example in which the electromagnetic valve SV1 is closed after the opening of the electromagnetic valve SV3 is controlled, the end of the vacuum pump 2a side is controlled by the opening control of the electromagnetic valve SV3 when switching to the parallel connection state. Since the solenoid valve SV1 is controlled to be closed after the movement of the air from the pipe P2a to the outside of the pipe P2a is permitted, the movement of the air from the pipe P2a to the pipe P1b is restricted. The situation that occurs is preferably avoided.

  In addition, when the two vacuum pumps are switched to the parallel connection state in the conventional vacuum exhaust device, if the first valve is opened prior to closing the second valve, the suction ports of both vacuum pumps are to be exhausted (suction target). ) The air discharged from the first pump flows into the pipe for connecting to the pipe, and the vacuum pressure in the pipe connected to the exhaust target (suction target) may decrease due to this. . On the other hand, in the suction system 1 of this example that controls the opening of the electromagnetic valve SV2 after performing the closing control of the electromagnetic valve SV1, the piping P2a passes through the pipe P3 to the piping P1b by the closing control of the electromagnetic valve SV1. Since the opening of the solenoid valve SV2 is controlled in a state where the flow of the air to be shut off, a decrease in the vacuum pressure in the pipe P1 due to the inflow of air sucked from the vacuum pump 2a toward the vacuum pump 2b is avoided. .

  Thereafter, by continuing the operation in the parallel connection state, the vacuum pressure in the pipe P1 gradually increases. When the state of the suction target changes and the air sucked from the suction target decreases per unit time (when the load on the suction system 1 decreases), the pipe P1 is sucked by the vacuum pumps 2a and 2b. The internal vacuum pressure exceeds a predetermined vacuum pressure (the “first vacuum pressure” described above). At this time, as described above, the control unit 4 performs the closing control of the electromagnetic valve SV2, the opening control of the electromagnetic valve SV1, and the closing control of the electromagnetic valve SV3 while continuing the operation of both the vacuum pumps 2a and 2b. It carries out in order and switches both vacuum pumps 2a and 2b to a serial connection state. Thereby, it will be in the state by which air is attracted | sucked from the suction object under the sufficiently high vacuum pressure required in the suction object.

  As described above, according to the suction system 1, the control unit 4 controls the opening of the electromagnetic valve SV1 to allow the movement of air from the pipe P2a to the pipe P1b, and then controls the electromagnetic valve SV3 to be closed. By restricting the movement of air from the outside of the pipe P2a toward the end on the vacuum pump 2a side and switching both vacuum pumps 2a and 2b to a serial connection state, the exhaust of the vacuum pump 2a is controlled prior to the opening control of the solenoid valve SV1. As a result of avoiding a situation in which the movement of air from the outlet toward the outside of the pipe P2a is restricted, it is possible to avoid a situation in which a shutoff operation occurs in the vacuum pump 2a when switching to the serial connection state. Thereby, since the situation where a big burden is applied to the vacuum pump 2a can be avoided, failure of the vacuum pump 2a can be preferably avoided.

  Further, according to the suction system 1, the control unit 4 controls the closing of the electromagnetic valve SV2, thereby restricting the movement of air from the connection portion of the pipe P3 in the pipe P1b toward the suction target, and then opening the electromagnetic valve SV1. By performing control and closing control of the electromagnetic valve SV3 to switch both the vacuum pumps 2a and 2b to the serial connection state, when the opening of the electromagnetic valve SV1 is controlled, it is discharged from the discharge port of the vacuum pump 2a to the pipe P2a. Since the air flowing into the pipe P1b through the pipe P3 does not move toward the pipe P1 (suction target), the vacuum pressure in the pipe P1 (the vacuum pressure supplied to the suction target) decreases when switching to the serial connection state. It is possible to preferably avoid the situation.

  Furthermore, according to this suction system 1, when the vacuum pressure in the pipe P1 specified by the control unit 4 based on the sensor signal from the pressure sensor 3 exceeds the “first vacuum pressure”, the solenoid valve SV2 By performing blockage control, opening control of the solenoid valve SV1, and blockage control of the solenoid valve SV3, and switching the vacuum pumps 2a and 2b to the serial connection state, the vacuum pumps 2a and 2b are automatically operated according to the state of the suction target. Therefore, a sufficient amount of air can be reliably sucked from the suction target under a sufficiently high vacuum pressure required for the suction target.

  Further, according to the suction system 1, the control unit 4 controls the opening of the electromagnetic valve SV3, thereby allowing the movement of air from the end on the vacuum pump 2a side toward the outside of the pipe P2a, and then the electromagnetic valve SV1. By controlling the blockage, the movement of air from the pipe P2a to the pipe P1b is restricted and the vacuum pumps 2a and 2b are switched to the parallel connection state, so that the air flowing from the end on the vacuum pump 2a side to the outside of the pipe P2a Since the movement of the air from the pipe P2a to the pipe P1b after the movement is permitted is restricted, it is possible to suitably avoid a situation in which the vacuum pump 2a causes a shut-off operation when switching to the parallel connection state. . Thereby, since the situation where a big burden is applied to the vacuum pump 2a can be avoided, failure of the vacuum pump 2a can be preferably avoided.

  Further, according to the suction system 1, the control unit 4 performs the opening control of the electromagnetic valve SV3 and the closing control of the electromagnetic valve SV1, and then controls the opening of the electromagnetic valve SV2, so that the suction target is changed to the vacuum pump 2b. By switching the vacuum pumps 2a and 2b to the parallel connection state while allowing the movement of the air toward the solenoid valve SV2 is controlled to be open after the movement of the air from the pipe P2a to the pipe P1b is restricted. As a result, the air discharged from the discharge port of the vacuum pump 2a to the pipe P2a and flowing into the pipe P1b via the pipe P3 does not move toward the pipe P1 (suction target). A situation in which the vacuum pressure in P1 (the vacuum pressure supplied to the suction target) decreases can also be suitably avoided.

  Furthermore, according to this suction system 1, when the vacuum pressure in the pipe P1 specified by the control unit 4 based on the sensor signal from the pressure sensor 3 falls below the “second vacuum pressure”, the solenoid valve SV3 By performing opening control, closing control of the solenoid valve SV1, and opening control of the solenoid valve SV2 to switch both the vacuum pumps 2a and 2b to the parallel connection state, both the vacuum pumps 2a and 2b are automatically operated according to the state of the suction target. Therefore, a sufficient amount of air can be reliably sucked from the suction target under a sufficiently high vacuum pressure required for the suction target.

  Next, another embodiment of the suction system will be described with reference to the accompanying drawings. In addition, about the component similar to said suction system 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The suction system 1A shown in FIG. 2 is another example of the “suction system”, and the vacuum pumps 2a and 2b switched to either the parallel connection state or the series connection state in the same manner as the suction system 1 described above. Thus, air can be sucked from various suction objects (vacuum pressure is supplied to the suction objects). In this suction system 1A, in place of the electromagnetic valve SV2 in the suction system 1 described above, the check valve CV2 disposed in the pipe P1b is caused to function as a “first on-off valve” so that the vacuum pump 2b is pulled from the suction target (pipe P1). The configuration is the same as that of the suction system 1 except that a configuration is adopted in which the movement of the air toward the suction target (pipe P1) from the connection portion of the pipe P3 in the pipe P1b is permitted. ing.

  In this suction system 1A, when a start switch of an operation unit (not shown) is operated, the control unit 4 controls the electromagnetic valve SV1 to a closed state and controls the electromagnetic valve SV3 to an open state, as well as an inverter circuit 2c. Is controlled to start operation of both vacuum pumps 2a, 2b. At this time, supply of electric power from the inverter circuit 2c causes the vacuum pump 2a to start sucking air in the pipe P1a, and the vacuum pump 2b starts to suck air in the pipe P1b.

  Further, the movement of air from the pipe P2a to the pipe P1b is restricted by the closing control of the electromagnetic valve SV1, and the flow of air (vacuum) from the discharge port of the vacuum pump 2a to the outside of the pipe P2a by the opening control of the electromagnetic valve SV3. Release of air from the pump 2a) is permitted. In this case, at the start of operation of the vacuum pumps 2a and 2b, the insides of the pipes P1, P1a, P1b, P2a, P2b, and P3 are at atmospheric pressure. Therefore, when the air in the pipe P1a is sucked by the vacuum pump 2a, the check valve CV1 is opened, and movement of air from the pipe P1 (suction target) toward the vacuum pump 2a is allowed, and the vacuum pump When the air in the pipe P1b is sucked by 2b, the check valve CV2 is opened, and movement of air from the pipe P1 (suction target) toward the vacuum pump 2b is allowed.

  As a result, both vacuum pumps 2a and 2b are connected in parallel, and air is sucked from the suction target by the vacuum pump 2a via the pipes P1 and P1a, and from the suction target by the vacuum pump 2b via the pipes P1 and P1b. Air is aspirated. Thereby, the inside of the pipes P1, P1a, P1b is in a vacuum state, and the vacuum pressure gradually increases according to the elapsed time from the start of operation of the vacuum pumps 2a, 2b.

  Further, the air sucked into the vacuum pump 2a through the pipes P1 and P1a is discharged from the discharge port to the pipe P2a. At this time, the solenoid valve SV1 arranged in the pipe P3 connected to the pipe P2a is controlled to be closed, and the ingress of air from the pipe P2a to the pipe P3 is restricted, but is arranged in the pipe P2a. Since the opening of the solenoid valve SV3 is controlled and the flow of air from the vacuum pump 2a to the outside of the pipe P2a is allowed, the vacuum pump 2a is discharged from the vacuum pump 2a to the pipe P2a without causing a cutoff operation. The discharged air passes through the electromagnetic valve SV3 and is released into the atmosphere. Further, the air sucked into the vacuum pump 2b through the pipes P1 and P1b is released from the discharge port into the atmosphere through the pipe P2b.

  On the other hand, the control unit 4 controls the closing of the electromagnetic valve SV1, the opening control of the electromagnetic valve SV3, and the power supply control from the inverter circuit 2c, and simultaneously outputs the sensor signal output from the pressure sensor 3. The calculation (specification) of the vacuum pressure in the piping P1 is started. In addition, the control unit 4 exceeds 93.0 kPa when a predetermined time of several seconds elapses after the calculated vacuum pressure exceeds 93.0 kPa (an example of “first vacuum pressure”) as an example. When the state is maintained (an example of “when exceeding the first vacuum pressure”), the opening of the solenoid valve SV1 is controlled while the operations of both vacuum pumps 2a and 2b are continued, and then the solenoid valve SV3 is turned on. Both vacuum pumps 2a and 2b are switched to a serial connection state by closing control. In addition, as the above “first vacuum pressure”, the amount of air sucked per unit time (the amount of increase in vacuum pressure per unit time) is switched to the series connection state rather than continuing the operation in the parallel connection state. What is necessary is just to prescribe | regulate the vacuum pressure which increases.

  At this time, the opening of the electromagnetic valve SV1 is controlled so that the pipe P2a connected to the discharge port of the vacuum pump 2a and the pipe P1b connected to the suction port of the vacuum pump 2b are connected via the pipe P3. Therefore, the movement of air from the pipe P2a to the pipe P1b is allowed, and the discharge port of the vacuum pump 2a and the suction port of the vacuum pump 2b are connected to each other. Further, by closing control of the electromagnetic valve SV3, the entry of the atmosphere into the pipe P2a and the release of the air discharged from the vacuum pump 2a into the pipe P2a are restricted.

  Further, as will be described later, the suction efficiency of the vacuum pump 2a is improved, the vacuum pressure in the pipes P1 and P1a is increased, and the air discharged from the vacuum pump 2a flows into the pipe P1b through the pipes P2a and P3. Since the vacuum pressure on the connection site side (vacuum pump 2b side) of the pipe P3 in the pipe P1b is reduced by the amount, the check valve CV2 is automatically closed, and vacuum is supplied from the pipe P1 (suction target) through the pipe P1b. The movement of air toward the pump 2b and the movement of air from the connection part of the pipe P3 in the pipe P1b toward the pipe P1 (suction target) are restricted. Thereby, both vacuum pumps 2a and 2b are switched to a serial connection state, and air from the suction target is sucked by the vacuum pump 2a, and air discharged from the vacuum pump 2a to the pipe P2a passes through the pipes P3 and P1b. It is sucked by the vacuum pump 2b and released to the atmosphere via the pipe P2b.

  Further, when both the vacuum pumps 2a and 2b are switched to the serial connection state, since the air discharged from the vacuum pump 2a is sucked by the vacuum pump 2b, the vacuum resistance is reduced by the amount that the exhaust resistance of the vacuum pump 2a is reduced. The suction efficiency of the pump 2a is improved. Therefore, by continuing the suction of air by both vacuum pumps 2a and 2b in the serial connection state, suction is performed even in a state where the vacuum pressure in the pipes P1a and P1 is higher than the vacuum pressure that can be reached in the parallel connection state. It becomes possible to suck air from the object. Thereby, the vacuum pressure in the pipes P1a and P1 further increases, and air is sucked from the suction target under a sufficiently high vacuum pressure required for the suction target.

  In this case, when the control unit 4 switches both vacuum pumps 2a and 2b to the serial connection state, in the suction system 1A of this example that controls the closing of the electromagnetic valve SV3 after the opening of the electromagnetic valve SV1, the suction system 1 described above is used. In the same manner as described above, since the air discharged from the vacuum pump 2a is inhaled by the vacuum pump 2b and the release to the atmosphere is restricted, a situation in which a shutoff operation occurs in the vacuum pump 2a is preferably avoided. Further, in the suction system 1A of the present example in which the “first on-off valve” is configured by the check valve CV2, the check valve CV2 is automatically set immediately after the opening of the electromagnetic valve SV1 is controlled when switching to the serial connection state. Therefore, the air that has moved from the vacuum pump 2a toward the pipe P1b via the pipes P2a and P3 does not flow into the pipe P1. For this reason, the situation where the vacuum degree in the piping P1 falls at the time of switching to a serial connection state is also avoided suitably.

  On the other hand, for example, when the state of the suction target changes and a large amount of air is sucked from the suction target per unit time (a state where the load on the suction system 1A is increased), in the serial connection state, from the suction target It may be difficult to suck air sufficiently, and the vacuum pressure in the pipe P1 may gradually decrease. Therefore, the control unit 4 has a vacuum pressure of 93.0 kPa (an example of “second vacuum pressure”) as an example based on the sensor signal output from the pressure sensor 3 during operation in a serial connection state. The vacuum pump 2a is in a state where a state of less than 93.0 kPa is maintained at the time when a predetermined time of about several seconds has passed since the pressure is less than (a case when the pressure is less than the second vacuum pressure). , 2b, while controlling the opening of the solenoid valve SV3, the solenoid valve SV1 is controlled to be closed, thereby switching both vacuum pumps 2a, 2b to the parallel connection state. In addition, as the “second vacuum pressure”, the amount of air sucked per unit time (the amount of increase in vacuum pressure per unit time) is switched to the parallel connection state rather than continuing the operation in the series connection state. When the vacuum pressure increases, that is, when switching from the serial connection state to the parallel connection state, the time required to increase to the vacuum pressure required for the suction target is shortened (short time to the required vacuum pressure) The vacuum pressure can be specified.

  At this time, the flow of air from the discharge port of the vacuum pump 2a toward the outside of the pipe P2a is permitted by controlling the opening of the electromagnetic valve SV3. Further, the movement of air from the pipe P2a to the pipe P1b is restricted by closing control of the electromagnetic valve SV1. Further, in this state where the movement of air from the pipe P2a to the pipe P1b is restricted, the vacuum pressure on the vacuum pump 2b side in the pipe P1b is increased by the air in the pipe P1b being sucked by the vacuum pump 2b. At this time, the vacuum pressure in the pipe P1 is reduced due to a change in the state of the suction target. Therefore, when the vacuum pressure on the vacuum pump 2b side in the pipe P1b becomes higher than the vacuum pressure on the pipe P1 side (the suction target side) in the pipe P1b due to the suction of air in the pipe P1b by the vacuum pump 2b. The valve CV2 is automatically opened, and movement of air from the pipe P1 toward the vacuum pump 2b is allowed.

  Thereby, both vacuum pumps 2a and 2b are switched to a parallel connection state, air is sucked from the suction target by the vacuum pump 2a via the pipes P1 and P1a, and from the suction target by the vacuum pump 2b via the pipes P1 and P1b. Air is sucked, and air sucked by the vacuum pump 2a is discharged to the pipe P2a and released to the atmosphere, and air sucked by the vacuum pump 2b is discharged to the pipe P2b and opened to the atmosphere. Therefore, the amount of air sucked per unit time is increased as compared to when both vacuum pumps 2a and 2b are operated in a series connection state, and as a result, the inside of the pipe P1 is larger than when the operation in the series connection state is continued. The vacuum pressure rises in a short time. As a result, air can be sucked from the suction target under a sufficiently high vacuum pressure required for the suction target in a relatively short time.

  In this case, in the suction system 1A of this example that controls the closing of the solenoid valve SV1 after opening the solenoid valve SV3, the opening control of the solenoid valve SV3 is performed at the time of switching to the parallel connection state in the same manner as the suction system 1 described above. As a result, the electromagnetic valve SV1 is controlled to be closed after the movement of air from the end on the vacuum pump 2a side to the outside of the pipe P2a is permitted, and the movement of air from the pipe P2a to the pipe P1b is restricted. The situation in which the shut-off operation occurs in the vacuum pump 2a is preferably avoided. Further, in the suction system 1A of the present example in which the “first on-off valve” is configured by the check valve CV2, when the vacuum pressure in the pipe P1b rises to some extent by suction by the vacuum pump 2b switched to the parallel connection state Since the check valve CV2 is automatically opened, the “first on-off valve” in the state where the vacuum pressure on the vacuum pump 2b side in the pipe P1b is lower than the vacuum pressure on the pipe P1 side (the suction target side) in the pipe P1b. "Is not open, thereby avoiding a situation where the vacuum pressure in the pipe P1 is lowered.

  Thereafter, by continuing the operation in the parallel connection state, the vacuum pressure in the pipe P1 gradually increases. When the state of the suction target changes and the air sucked from the suction target decreases per unit time (when the load on the suction system 1A decreases), the pipe P1 is sucked by suction by both vacuum pumps 2a and 2b. The internal vacuum pressure exceeds a predetermined vacuum pressure (the “first vacuum pressure” described above). At this time, as described above, the control unit 4 continues the operation of both the vacuum pumps 2a and 2b, and executes the opening control of the electromagnetic valve SV1 and the closing control of the electromagnetic valve SV3 in this order to perform both vacuums. The pumps 2a and 2b are switched to the serial connection state. Thereby, it will be in the state by which air is attracted | sucked from the suction object under the sufficiently high vacuum pressure required in the suction object.

  Thus, according to this suction system 1A, the control unit 4 controls the opening of the solenoid valve SV1, thereby allowing the movement of air from the pipe P2a to the pipe P1b, and then closing the solenoid valve SV3. By restricting the movement of air from the outside of the pipe P2a toward the end on the vacuum pump 2a side and switching the vacuum pumps 2a and 2b to the serial connection state, the electromagnetic valve SV1 is controlled in the same manner as the suction system 1 described above. Prior to opening control, the situation in which the movement of air from the discharge port of the vacuum pump 2a toward the outside of the pipe P2a can be avoided. As a result, the situation in which the vacuum pump 2a is cut off when switching to the serial connection state is avoided. be able to. Thereby, since the situation where a big burden is applied to the vacuum pump 2a can be avoided, failure of the vacuum pump 2a can be preferably avoided.

  In addition, according to the suction system 1A, the check valve CV2 that allows the movement of air from the suction target toward the vacuum pump 2b and restricts the movement of air from the connection portion of the pipe P3 in the pipe P1b toward the suction target “ By configuring the “first on-off valve”, the opening of the electromagnetic valve SV1 is controlled when switching to the serial connection state, and the air discharged from the discharge port of the vacuum pump 2a to the pipe P2a flows into the pipe P1b via the pipe P3. Since the check valve CV2 is automatically switched to the closed state and the movement of air from the connection part of the pipe P3 to the pipe P1 (suction target) in the pipe P1b is restricted, A situation in which the vacuum pressure in the pipe P1 (the vacuum pressure supplied to the suction target) decreases can be suitably avoided. In addition, since one of the plurality of on-off valves necessary for switching to the serial connection state is configured with an inexpensive check valve CV2, the manufacturing cost of the suction system 1A can be sufficiently reduced.

  Furthermore, according to the suction system 1A, when the vacuum pressure in the pipe P1 specified by the control unit 4 based on the sensor signal from the pressure sensor 3 exceeds the “first vacuum pressure”, the solenoid valve SV1 By performing opening control and closing control of the electromagnetic valve SV3 to switch both vacuum pumps 2a and 2b to a serial connection state, both vacuum pumps 2a, 2a, 2b, Since 2b can be automatically switched to the serial connection state, a sufficient amount of air can be reliably sucked from the suction target under a sufficiently high vacuum pressure required for the suction target.

  Further, according to the suction system 1A, the control unit 4 controls the opening of the electromagnetic valve SV3, thereby allowing the movement of air from the end on the vacuum pump 2a side to the outside of the pipe P2a, and then the electromagnetic valve SV1. By closing control, the movement of the air from the pipe P2a to the pipe P1b is restricted, and both vacuum pumps 2a and 2b are switched to the parallel connection state, so that the end on the vacuum pump 2a side is the same as the suction system 1 described above. Since the movement of air from the pipe P2a to the pipe P1b is restricted after the movement of the air from the section toward the outside of the pipe P2a is permitted, the cutoff operation is performed on the vacuum pump 2a when switching to the parallel connection state. The situation which arises can be avoided suitably. Thereby, since the situation where a big burden is applied to the vacuum pump 2a can be avoided, failure of the vacuum pump 2a can be preferably avoided.

  In addition, according to the suction system 1A, the check valve CV2 that allows the movement of air from the suction target toward the vacuum pump 2b and restricts the movement of air from the connection portion of the pipe P3 in the pipe P1b toward the suction target “ By configuring the “first on-off valve”, the solenoid valve SV1 is controlled to be closed when switching to the parallel connection state, and the movement of air from the pipe P2a to the pipe P1b is restricted, and in this state, the inside of the pipe P1b by the vacuum pump 2b When the vacuum pressure in the pipe P1b is sufficiently increased due to the suction of the air, the check valve CV2 is automatically switched to the open state, and the movement of air from the pipe P1 (suction target) to the vacuum pump 2b is allowed. Therefore, a situation in which the vacuum pressure in the pipe P1 (the vacuum pressure supplied to the suction target) is reduced when switching to the parallel connection state is also suitably avoided. Rukoto can. In addition, since one of the plurality of on-off valves necessary for switching to the parallel connection state is configured with an inexpensive check valve CV2, the manufacturing cost of the suction system 1A can be sufficiently reduced.

  Furthermore, according to this suction system 1A, when the vacuum pressure in the pipe P1 specified by the control unit 4 based on the sensor signal from the pressure sensor 3 falls below the “second vacuum pressure”, the solenoid valve SV3 By switching the vacuum pumps 2a and 2b to the parallel connection state by performing the opening control and the closing control of the electromagnetic valve SV1, the vacuum pumps 2a and 2b are automatically switched to the parallel connection state according to the state of the suction target. Therefore, it is possible to reliably suck a sufficient amount of air from the suction target under a sufficiently high vacuum pressure required for the suction target.

  The example in which the “first vacuum pressure” and the “second vacuum pressure” are the same vacuum pressure (93.0 kPa in the above example) has been described, but the “first vacuum pressure” is the “second vacuum pressure”. It is also possible to define a higher vacuum pressure.

1,1A Suction system 1,1A
2a, 2b Vacuum pump 3 Pressure sensor 4 Control unit CV1, CV2 Check valve P1, P1a, P1b, P2a, P2b, P3 Piping SV1 to SV3 Solenoid valve

Claims (8)

A parallel connection state in which the first suction device and the second suction device are provided so that gas can be sucked from the suction target by the suction devices, and the suction ports of the suction devices are connected to the suction target, respectively. The suction port of the first suction device is connected to the suction target and can be switched to either a serial connection state in which the suction port of the second suction device is connected to the discharge port of the first suction device. A suction system,
A control unit that switches and controls the suction devices to either the parallel connection state or the series connection state;
A first connection pipe for connecting the suction port of the first suction device to the suction target;
A second connection pipe for connecting the suction port of the second suction device to the suction target;
A first on-off valve disposed in the second connection pipe;
A discharge pipe connected to the discharge port of the first suction device;
A second on-off valve disposed in the discharge pipe;
One end portion is connected between the end portion on the first suction device side in the discharge pipe and the disposition site of the second on-off valve, and the end on the second suction device side in the second connection pipe A third connecting pipe having the other end connected between the first and the first on-off valve,
A third on-off valve disposed in the third connection pipe,
The first on-off valve, the second on-off valve, and the third on-off valve are respectively configured by electromagnetic valves that are controlled to open and close by the control unit,
The control unit restricts the movement of the gas from the connection portion of the third connection pipe in the second connection pipe to the suction target by closing the first on-off valve, and then the first 3. After allowing the gas to move from the discharge pipe to the second connection pipe by controlling the opening of the on-off valve, the second on-off valve is closed to control the second on-off valve from the outside of the discharge pipe. The suction system which controls the movement of the gas which goes to the edge part by the side of 1 suction device, and switches both said suction devices to the said serial connection state. A pressure sensor for detecting a vacuum pressure in the first connection pipe;
The control unit specifies a vacuum pressure in the first connection pipe based on a sensor signal from the pressure sensor, and when the specified vacuum pressure exceeds a predetermined first vacuum pressure, the closing control of the first on-off valve, the third suction system of claim 1, wherein the opening control of the on-off valve and that performs closed control of the second on-off valve switching the two suction device to the series connection state. A parallel connection state in which the first suction device and the second suction device are provided so that gas can be sucked from the suction target by the suction devices, and the suction ports of the suction devices are connected to the suction target, respectively. The suction port of the first suction device is connected to the suction target and can be switched to either a serial connection state in which the suction port of the second suction device is connected to the discharge port of the first suction device. A suction system,
A control unit that switches and controls the suction devices to either the parallel connection state or the series connection state;
A first connection pipe for connecting the suction port of the first suction device to the suction target;
A second connection pipe for connecting the suction port of the second suction device to the suction target;
A first on-off valve disposed in the second connection pipe;
A discharge pipe connected to the discharge port of the first suction device;
A second on-off valve disposed in the discharge pipe;
One end portion is connected between the end portion on the first suction device side in the discharge pipe and the disposition site of the second on-off valve, and the end on the second suction device side in the second connection pipe A third connecting pipe having the other end connected between the first and the first on-off valve,
A third on-off valve disposed in the third connection pipe,
The first on-off valve allows movement of gas from the suction target toward the second suction device, and moves gas from the connection portion of the third connection pipe in the second connection pipe toward the suction target. It consists of a check valve that regulates
The second on-off valve and the third on-off valve are respectively constituted by electromagnetic valves that are controlled to open and close by the control unit,
The controller controls the opening of the third on-off valve to allow gas to move from the discharge pipe to the second connection pipe, and then controls the second on-off valve to close the exhaust. A suction system that restricts the movement of the gas from the outside of the piping to the end on the first suction device side and switches both suction devices to the serial connection state. A pressure sensor for detecting a vacuum pressure in the first connection pipe;
The control unit specifies a vacuum pressure in the first connection pipe based on a sensor signal from the pressure sensor, and when the specified vacuum pressure exceeds a predetermined first vacuum pressure, The suction system according to claim 3 , wherein opening control of the third on-off valve and closing control of the second on-off valve are performed to switch the suction devices to the serial connection state. A parallel connection state in which the first suction device and the second suction device are provided so that gas can be sucked from the suction target by the suction devices, and the suction ports of the suction devices are connected to the suction target, respectively. The suction port of the first suction device is connected to the suction target and can be switched to either a serial connection state in which the suction port of the second suction device is connected to the discharge port of the first suction device. A suction system,
A control unit that switches and controls the suction devices to either the parallel connection state or the series connection state;
A first connection pipe for connecting the suction port of the first suction device to the suction target;
A second connection pipe for connecting the suction port of the second suction device to the suction target;
A first on-off valve disposed in the second connection pipe;
A discharge pipe connected to the discharge port of the first suction device;
A second on-off valve disposed in the discharge pipe;
One end portion is connected between the end portion on the first suction device side in the discharge pipe and the disposition site of the second on-off valve, and the end on the second suction device side in the second connection pipe A third connecting pipe having the other end connected between the first and the first on-off valve,
A third on-off valve disposed in the third connection pipe,
The first on-off valve, the second on-off valve, and the third on-off valve are respectively configured by electromagnetic valves that are controlled to open and close by the control unit,
The controller controls the opening of the second on-off valve to allow the movement of gas from the end on the first suction device side to the outside of the discharge pipe, and then controls the third on-off valve to be closed. By restricting the movement of the gas from the discharge pipe to the second connection pipe, the opening of the first on-off valve is then controlled to control the movement of the gas from the suction target to the second suction device. A suction system that allows movement and switches the suction devices to the parallel connection state. A pressure sensor for detecting a vacuum pressure in the first connection pipe;
The control unit specifies a vacuum pressure in the first connection pipe based on a sensor signal from the pressure sensor, and when the specified vacuum pressure falls below a predetermined second vacuum pressure, The suction system according to claim 5 , wherein opening control of the second opening / closing valve, closing control of the third opening / closing valve, and opening control of the first opening / closing valve are performed to switch the suction devices to the parallel connection state. A parallel connection state in which the first suction device and the second suction device are provided so that gas can be sucked from the suction target by the suction devices, and the suction ports of the suction devices are connected to the suction target, respectively. The suction port of the first suction device is connected to the suction target and can be switched to either a serial connection state in which the suction port of the second suction device is connected to the discharge port of the first suction device. A suction system,
A control unit that switches and controls the suction devices to either the parallel connection state or the series connection state;
A first connection pipe for connecting the suction port of the first suction device to the suction target;
A second connection pipe for connecting the suction port of the second suction device to the suction target;
A first on-off valve disposed in the second connection pipe;
A discharge pipe connected to the discharge port of the first suction device;
A second on-off valve disposed in the discharge pipe;
One end portion is connected between the end portion on the first suction device side in the discharge pipe and the disposition site of the second on-off valve, and the end on the second suction device side in the second connection pipe A third connecting pipe having the other end connected between the first and the first on-off valve,
A third on-off valve disposed in the third connection pipe,
The first on-off valve allows movement of gas from the suction target toward the second suction device, and moves gas from the connection portion of the third connection pipe in the second connection pipe toward the suction target. It consists of a check valve that regulates
The second on-off valve and the third on-off valve are respectively constituted by electromagnetic valves that are controlled to open and close by the control unit,
The controller controls the opening of the second on-off valve to allow the movement of gas from the end on the first suction device side to the outside of the discharge pipe, and then controls the third on-off valve to be closed. Thus, a suction system that restricts the movement of gas from the discharge pipe to the second connection pipe and switches the suction devices to the parallel connection state. A pressure sensor for detecting a vacuum pressure in the first connection pipe;
The control unit specifies a vacuum pressure in the first connection pipe based on a sensor signal from the pressure sensor, and when the specified vacuum pressure falls below a predetermined second vacuum pressure, The suction system according to claim 7 , wherein opening control of the second on-off valve and closing control of the third on-off valve are performed to switch the suction devices to the parallel connection state.

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