TUBE PUMP SYSTEM AND CONTROL METHOD OF THE SAME

Provided is a tube pump system including: a tube pump; a pipe including a flow channel causing a liquid delivered from a tube to flow formed therein; an orifice arranged at a first predetermined position; a selector valve arranged at a second predetermined position; and a control unit. The control unit controls the tube pump and the selector valve to synchronize a delivering timing to switch the tube pump from the stop state to the delivering state and a flowing timing to switch the selector valve from the blocking state to the flowing state and synchronize a stop timing to switch the tube pump from the delivering state to the stop state and a blocking timing to switch the selector valve from the flowing state to the blocking state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority benefits under U.S.C. § 119 to Japanese Patent Application No. 2023-116259 filed on Jul. 14, 2023, the contents of which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a tube pump system and a method for controlling the tube pump system.

2. Description of Related Art

Conventionally, a tube pump has been known where a tube having flexibility is intermittently compressed by a plurality of rollers so as to supply a liquid in the tube under pressure. The tube pump intermittently supplies the liquid under pressure and hence, pulsation (an operation where an increase and a decrease in flow rate is repeated) is generated in the liquid supplied under pressure.

Japanese Unexamined Patent Application, Publication No. 2018-44488 (patent document 1) discloses the following problem. When a tube compressed by a roller returns to the original shape, pulsation is generated due to a phenomenon that a liquid is drawn back toward the tube pump side from a path on the downstream side. Patent document 1 discloses a technique where, to suppress such pulsation, when one of a pair of roller units passes through a separation position, at which the roller unit separates from the tube, the pressure of a liquid in the tube closed due to contact with the pair of roller units is caused to rise. According to patent document 1, the pressure of a liquid in the tube is caused to rise and hence, it is possible to suppress the phenomenon that a liquid is drawn back toward the tube pump side.

In life science fields such as medical care or physical and chemical science, there may be a demand for intermittent ejection (dispense) of a fixed amount of a liquid used as an analyte or a sample. In a tube pump system disclosed in patent document 1, a pair of drive units configured to drive a pair of roller parts are controlled so that a flow rate corresponding to a liquid value measured by a flow meter is a predefined target flow rate. The tube pump system disclosed in patent document 1 is advantageous in that it is possible to suppress pulsation of an ejected liquid but is not optimized for use of intermittent ejection of a fixed amount of a liquid.

BRIEF SUMMARY

The present disclosure has been made in view of such circumstances and intends to provide a tube pump system and a control method of the same that enable a liquid delivered from a tube pump to a pipe to be intermittently ejected by a fixed amount from the pipe.

To achieve the above object, the tube pump system and the control method of the same of the present disclosure employ the following solutions.

The tube pump system according to one aspect of the present disclosure includes: a tube pump configured to deliver a liquid in a tube formed of a flexible material by intermittently pinching the tube and perform switching between a delivering state for delivering a liquid and a stop state for not delivering a liquid; a pipe connected to the tube at one end of the pipe and including a flow channel formed inside the pipe, the flow channel causing a liquid delivered from the tube to flow in a flow direction from the one end to the other end; a reduced diameter part arranged at a first predetermined position between the one end and the other end of the pipe and providing the smallest sectional area of a channel cross section orthogonal to the flow direction in the flow channel; a selector valve arranged at a second predetermined position between the one end and the other end of the pipe and configured to perform switching between a flowing state where a liquid passes through the second predetermined position and a blocking state where a liquid flow is blocked at the second predetermined position; and a control unit configured to control the tube pump and the selector valve so that a liquid is intermittently ejected from the other end of the pipe. The control unit controls the tube pump and the selector valve to synchronize a delivering timing and a flowing timing and synchronize a stop timing and a blocking timing, the delivering timing being a timing to switch the state of the tube pump from the stop state to the delivering state, the flowing timing being a timing to switch the state of the selector valve from the blocking state to the flowing state, the stop timing being a timing to switch the state of the tube pump from the delivering state to the stop state, and the blocking timing being a timing to switch the state of the selector valve from the flowing state to the blocking state.

According to the tube pump system of one aspect of the present disclosure, the tube pump intermittently pinches the tube formed of a flexible material, and thereby a liquid in the tube is delivered and guided to the flow channel formed inside the pipe whose one end is connected to the tube. The reduced diameter part providing the smallest sectional area of the channel cross section in the flow channel is arranged at the first predetermined position in the pipe. Since the liquid flow resistance at the reduced diameter part is largest in the flow channel, a liquid flowing through the flow channel from one end of the pipe to the reduced diameter part is in a state where the dynamic pressure is lower and the static pressure is higher compared to a case where the reduced diameter part is not provided in the flow channel.

According to the tube pump system of one aspect of the present disclosure, the tube pump and the selector valve are controlled so that the delivering timing at the tube pump and the flowing timing at the selector valve are synchronized and the stop timing at the tube pump and the blocking timing at the selector valve are synchronized. Since the stop timing at the tube pump and the blocking timing at the selector valve are synchronized, liquid ejection from the other end of the pipe is stopped in a state where the static pressure of the liquid is maintained constant between the one end of the pipe and the second predetermined position at which the selector valve is arranged.

Further, since the delivering timing at the tube pump and the flowing timing at the selector valve are synchronized, liquid ejection from the other end of the pipe is started in a state where the static pressure of the liquid is maintained constant between the one end of the pipe and the second predetermined position at which the selector valve is arranged. Since the start and the stop of the liquid ejection from the other end of the pipe are switched in a state where the static pressure of the liquid is maintained constant between the one end of the pipe and the second predetermined position at which the selector valve is arranged, the liquid delivered from the tube pump to the pipe can be intermittently ejected by a fixed amount from the other end of the pipe.

The tube pump system according to one aspect of the present disclosure may be configured such that the tube pump has an accommodation part having an inner circumferential face arc-shaped about an axis, the tube being arranged on the inner circumferential face, a pair of roller parts accommodated in the accommodation part and configured to be rotated about the axis with the tube being closed from a closure position to a release position about the axis, and a pair of drive units configured to rotate each of the pair of roller parts in the same direction about the axis, the tube pump system further includes a pressure detecting unit to determine a pressure of a liquid delivered from the tube to the pipe, and the control unit controls each of the pair of drive units so that a variation range of the pressure of the liquid determined by the pressure detecting unit is within predetermined values when the pair of roller parts are rotated by at least one turn.

According to the tube pump system of the present configuration, the pair of roller parts are rotated in the same direction about the axis by the pair of drive units, respectively, and thereby the pair of roller parts are rotated from the closure position to the release position while pinching the tube. The control unit controls each of the pair of drive units to allow a liquid flowing in from the one end of the tube to be ejected from the other end of the tube. The variation range of a liquid pressure determined by the pressure detecting unit in at least one turn of rotation of the pair of roller parts represents how large the pulsation of the liquid pumped by the tube pump system is. When the tube that has been pinched by the roller parts by one of the pair of roller parts passing through the release position returns to the original shape, a larger pressure difference between the pressure of the liquid downstream of the release position and the pressure of the liquid upstream of the release position results in a larger variation range of the pressure. In the tube pump system of the present configuration, the control unit controls each of the pair of drive units so that the pressure variation range determined by the pressure detecting unit is within predetermined values. Thus, even when the state of pulsation dynamically changes, the pulsation can be suitably suppressed in accordance with the change.

The tube pump system of the above configuration may be formed such that the control unit controls a first rotation angle and a second rotation angle so that the variation range of the pressure determined by the pressure detecting unit is within the predetermined value, the first rotation angle being an angle about the axis between the pair of roller parts when a first one of the roller parts passes through the closure position, and the second rotation angle being an angle about the axis between the pair of roller parts when a second one of the roller parts passes through the release position.

According to the tube pump system of the present form, the pressure difference between the downstream liquid and the upstream liquid of the release position is in accordance with the first rotation angle and the second rotation angle. That is, a larger difference between the first rotation angle and the second rotation angle results in a higher pressure of the liquid in the tube closed due to the contact with the pair of roller parts, and a smaller difference between the first rotation angle and the second rotation angle results in a lower pressure of the liquid in the tube closed due to the contact with the pair of roller parts.

Accordingly, in the tube pump system of the present form, the control unit controls the first rotation angle about the axis between the pair of roller parts when the first roller part passes through the closure position and controls the second rotation angle about the axis between the pair of roller parts when the second roller part passes through the release position so that the variation range of the pressure determined by the pressure detecting unit is within predetermined values. According to the tube pump system of the present form, even when the state of pulsation dynamically changes, the pulsation can be suitable suppressed in accordance with the change.

The tube pump system according to one aspect of the present disclosure may be configured such that the first predetermined position at which the reduced diameter part is arranged is present between the one end of the pipe and the second predetermined position at which the selector valve is arranged, and the volume of the flow channel from the first predetermined position to the second predetermined position in the pipe is 1/10 or less of the volume from the one end of the pipe to the second predetermined position.

According to the tube pump system of the present configuration, the volume of the flow channel from the first predetermined position to the second predetermined position in the pipe is 1/10 or less of the volume from the one end of the pipe to the second predetermined position. Thus, when the tube pump is in the stop state and the selector valve is in the blocking state, it is possible to suppress the flow rate of a liquid flowing out from the first predetermined position at which the reduced diameter part is arranged to the second position at which the selector valve is arranged. It is thus possible to suitably suppress that the pressure of a liquid in the flow channel from the one end of the pipe to the reduced diameter part is reduced and the flow rate of the liquid intermittently ejected from the pipe is reduced accordingly.

The tube pump system according to one aspect of the present disclosure may be configured such that the control unit controls the tube pump and the selector valve so that a timing after a first predetermined period elapsed from the delivering timing is the flowing timing and that a timing after a second predetermined period elapsed from the stop timing is the blocking timing.

According to the tube pump system of the present configuration, by delaying the flowing timing by the first predetermined period from the delivering timing, it is possible to switch the state of the tube pump from the stop state to the delivering state to increase the pressure of a liquid held in the pipe and then switch the state of the selector valve from the blocking state to the flowing state to increase the ejecting amount of the liquid.

Further, by delaying the blocking timing by the second predetermined period from the stop timing, it is possible to switch the state of the selector valve from the flowing state to the blocking state to reduce the pressure of a liquid in the pipe in the blocking state without switching the state of the tube pump from the delivering state to the stop state to increase the pressure of the liquid held in the pipe. Further, by suitably adjusting the first predetermined period and the second predetermined period, it is possible to adjust the ejecting amount of the intermittently ejected liquid to a suitable amount.

The tube pump system according to one aspect of the present disclosure may be configured such that the control unit controls the tube pump and the selector valve so that a timing after a third predetermined period elapsed from the flowing timing is the delivering timing and that a timing after a fourth predetermined period elapsed from the blocking timing is the stop timing.

According to the tube pump system of the present configuration, by delaying the delivering timing by the third predetermined period from the flowing timing, it is possible to switch the state of the selector valve from the blocking state to the flowing state to reduce the pressure of a liquid held in the pipe and then switch the state of the tube pump from the stop state to the delivering state to reduce the ejecting amount of the liquid.

Further, by delaying the stop timing by the fourth predetermined period from the blocking timing, it is possible to switch the state of the selector valve from the flowing state to the blocking state to increase the pressure of a liquid held in the pipe and then switch the state of the tube pump from the delivering state to the stop state to increase the pressure of the liquid in the pipe in the blocking state. Further, by suitably adjusting the third predetermined period and the fourth predetermined period, it is possible to adjust the ejecting amount of the intermittently ejected liquid to a suitable amount.

In a control method of a tube pump system according to one aspect of the present disclosure, the tube pump system includes a tube pump configured to deliver a liquid in a tube formed of a flexible material by intermittently pinching the tube and perform switching between a delivering state for ejecting a liquid and a stop state for not delivering a liquid, a pipe connected to the tube at one end of the pipe and including a flow channel formed inside the pipe, the flow channel causing a liquid delivered from the tube to flow in a flow direction from the one end to the other end, a reduced diameter part arranged at a first predetermined position between the one end and the other end of the pipe and providing the smallest sectional area of a channel cross section orthogonal to the flow direction in the flow channel, and a selector valve arranged at a second predetermined position between the one end and the other end of the pipe and configured to perform switching between a flowing state where a liquid passes through the second predetermined position and a blocking state where a liquid flow is blocked at the second predetermined position. The control method includes: a first control step of controlling the tube pump and the selector valve to synchronize a delivering timing and a flowing timing, the delivering timing being a timing to switch the state of the tube pump from the stop state to the delivering state, and the flowing timing being a timing to switch the state of the selector valve from the blocking state to the flowing state; and a second control step of controlling the tube pump and the selector valve to synchronize a stop timing and a blocking timing, the stop timing being a timing to switch the state of the tube pump from the delivering state to the stop state, and the blocking timing being a timing to switch the state of the selector valve from the flowing state to the blocking state.

According to a control method of the tube pump system of one aspect of the present disclosure, the tube pump intermittently pinches the tube formed of a flexible material, and thereby a liquid in the tube is delivered and guided to the flow channel formed inside the pipe whose one end is connected to the tube. The reduced diameter part providing the smallest sectional area of the channel cross section in the flow channel is arranged at the first predetermined position in the pipe. Since the liquid flow resistance at the reduced diameter part is largest in the flow channel, a liquid flowing through the flow channel from one end of the pipe to the reduced diameter part is in a state where the dynamic pressure is lower and the static pressure is higher compared to a case where the reduced diameter part is not provided in the flow channel.

According to a control method of the tube pump system of one aspect of the present disclosure, the tube pump and the selector valve are controlled so that the delivering timing at the tube pump and the flowing timing at the selector valve are synchronized and the stop timing at the tube pump and the blocking timing at the selector valve are synchronized. Since the stop timing at the tube pump and the blocking timing at the selector valve are synchronized, liquid ejection from the other end of the pipe is stopped in a state where the static pressure of the liquid is maintained constant between the one end of the pipe and the second predetermined position at which the selector valve is arranged.

Further, since the delivering timing at the tube pump and the flowing timing at the selector valve are synchronized, liquid ejection from the other end of the pipe is started in a state where the static pressure of the liquid is maintained constant between the one end of the pipe and the second predetermined position at which the selector valve is arranged. Since the start and the stop of the liquid ejection from the other end of the pipe are switched in a state where the static pressure of the liquid is maintained constant between the one end of the pipe and the second predetermined position at which the selector valve is arranged, the liquid delivered from the tube pump to the pipe can be intermittently ejected by a fixed amount from the pipe.

According to the present disclosure, a tube pump system and a control method of the same are provided that enable a liquid delivered from a tube pump to a pipe to be intermittently ejected by a fixed amount from the pipe.

DETAILED DESCRIPTION

First Embodiment

A tube pump system according to a first embodiment of the present disclosure and one embodiment of a control method thereof will be described below with reference to the drawings. A tube pump system700of the present embodiment is a device that pumps a liquid from an inflow end701to an outflow end702and intermittently ejects a fixed amount of a liquid from the outflow end702. For example, the liquid pumped from the tube pump system700of the present embodiment is a liquid used as an analyte or a sample.

As illustrated inFIG.1, a tube pump system700of the present embodiment includes a tube pump100, a pipe200, a pressure sensor (pressure detecting unit)300, an orifice (reduced diameter part)400, a selector valve500, and a control unit600. Respective features of the tube pump system700of the present embodiment will be described below.

The tube pump100is a device that pumps a liquid from the inflow end701to the outflow end702. The tube pump100pumps a liquid by repeating an operation of moving rollers while pinching a flexible tube101by the rollers. The liquid ejected from the tube pump100to the pipe200passes through the orifice400and the selector valve500and reaches the outflow end702. The state of the tube pump100is switched by the control unit600between a delivering state for delivering a liquid and a stop state for not delivering a liquid. The detail of the tube pump100will be described later.

The pipe200is a pipe member whose one end200ais connected to the tube101of the tube pump100and in which a flow channel for causing a liquid delivered from the tube101to flow in a flow direction from the one end200ato the other end200bis formed. A nozzle201is attached to the other end200bof the pipe200. The pipe200is formed of a flexible material (for example, a resin material such as silicone). The pipe200can maintain the pressure of a liquid flowing through the flow channel to be higher than the atmospheric pressure when the channel sectional area of the orifice400is suitably set.

As illustrated inFIG.1, a first predetermined position P1at which the orifice400is arranged is present between the one end200aof the pipe200and a second predetermined position P2at which the selector valve500is arranged. The volume of the flow channel from the first predetermined position P1to the second predetermined position P2in the pipe200is preferably 1/10 or less of the volume from the one end200aof the pipe200to the second predetermined position P2.

When the channel sectional area of the pipe200is the same in the entire section except for the orifice400, the length L3of the flow channel from the first predetermined position P1to the second predetermined position P2in the pipe200is preferably 1/10 or less of the length L2from the one end200aof the pipe200to the second predetermined position P2. The length L2is a length of the sum of the length L1from the one end200aof the pipe200to the first predetermined position Pl and the length L3.

The pressure sensor300is a device that determines the pressure of a liquid delivered from the tube101of the tube pump100to the pipe200. The pressure sensor300is arranged upstream in the flow direction from the orifice400in the pipe200that guides a liquid from the tube pump100to the selector valve500. The pressure sensor300transfers a determined pressure to the control unit600.

The orifice400is a member arranged at the first predetermined position P1in the flow channel between the one end200aand the other end200bof the pipe200and providing the smallest sectional area of the channel cross section orthogonal to the flow direction in the flow channel. The orifice400is a member for maximizing a liquid flow resistance in the flow channel to increase the static pressure of a liquid in the upstream portion from the orifice400in the flow direction of the pipe200.

Herein, it is desirable to set the sectional area of the channel cross section of the orifice400such that the static pressure of a liquid in the upstream portion from the orifice400in the flow direction of the pipe200ranges from 20 kPaG to 250 kPaG. It is desirable to set the sectional area of the channel cross section of the orifice400to range, in particular, from 90 kPaG to 110 kPaG. Herein, “G” means a gage pressure. The sectional area of the channel cross section defined by the orifice400is set to a range of 5% or larger and 70% or smaller, for example, relative to the sectional area of the channel cross section of the remaining portion of the pipe200.

The selector valve500is a valve body arranged at the second predetermined position P2between the one end200aand the other end200bof the pipe200. The selector valve500switches the state between a flowing state where a liquid passes through the second predetermined position P2and a blocking state where a liquid flow is blocked at the second predetermined position P2. For example, the selector valve500is a pinch valve that pinches the outer circumference face of the flexible pipe200to close the fluid channel.

The control unit600is a device that controls the tube pump100and the selector valve500so that a fixed amount of a liquid is intermittently ejected from the other end200bof the pipe200. The control unit600controls each of a first drive unit50and a second drive unit60described later so as to cause a liquid flowing in from one end of the flexible tube101of the tube pump100to be ejected from the other end of the tube101.

As described later, the control unit600controls the tube pump100and the selector valve500to synchronize a delivering timing to switch the state of the tube pump100from the stop state to the delivering state and a flowing timing to switch the state of the selector valve500from the blocking state to the flowing state. Further, the control unit600controls the tube pump100and the selector valve500to synchronize a delivering timing to switch the state of the tube pump100from the delivering state to the stop state and a blocking timing to switch the state of the selector valve500from the flowing state to the blocking state.

As shown inFIG.1, the control unit600includes a memory unit610. The memory unit610stores a program performed by the control unit600. The control unit600reads and performs the program stored in the memory unit610, thus performing respective processes mentioned later. The memory unit610is formed of a nonvolatile memory capable of rewriting data, for example. As will be mentioned later, the control unit600adjusts a control waveform for controlling the first drive unit50and the second drive unit60, and stores the adjusted control waveform in the memory unit610. The control unit600reads the control waveform stored in the memory unit610so that the control unit600can control the first drive unit50and the second drive unit60using the adjusted control waveform.

Next, the tube pump100of the tube pump system700will be explained.FIG.2is a front view of a tube pump illustrated inFIG.1.FIG.3is a sectional view taken along the arrow A-A of the tube pump illustrated inFIG.2.

The tube pump100of this embodiment shown inFIG.2is a device where a first roller unit10(first contact member) and a second roller unit20(second contact member) are rotated around an axis line X1(first axis line) in the same direction so as to make a fluid in a tube101which flows into the tube101discharge from an inflow-side end portion101ato an outflow-side end portion101b. The pipe200is connected to the outflow-side end portion101b.FIG.2shows the tube pump100in a state where a cover83shown inFIG.3is removed.

In the tube pump100, the tube101is arranged in a circular-arc shape around the axis line X1along an inner peripheral surface82bof a recess82aof a roller housing unit82that houses the first roller unit10and the second roller unit20. As shown inFIG.2, the first roller unit10and the second roller unit20housed in the roller housing unit82are rotated around the axis line X1along a counter-clockwise rotation direction (a direction shown by an arrow inFIG.2) while being in contact with the tube101.

As shown inFIG.3, the tube pump100of the embodiment includes: the first roller unit10and the second roller unit20that rotate around the axis X1while being in contact with the tube101; a drive shaft30(a shaft member) that is arranged on the axis X1and is coupled to the first roller unit10; a drive cylinder (a cylindrical member)40that is coupled to the second roller unit20; a first drive unit50that transmits a drive force to the drive shaft30; a second drive unit60; and a transmission mechanism70(a transmission unit) that transmits a drive force of the second drive unit60to the drive cylinder40.

The first roller unit10has: a first roller11that rotates around an axis parallel to the axis X1while being in contact with the tube101; a first roller support member12coupled to the drive shaft30so as to integrally rotate around the axis X1; and a first roller shaft13both ends of which are supported by the first roller support member12, and to which the first roller11is rotatably attached.

The second roller unit20has: a second roller21that rotates around an axis parallel to the axis X1while being in contact with the tube101; a second roller support member22coupled to the drive cylinder40so as to integrally rotate around the axis X1; and a second roller shaft23both ends of which are supported by the second roller support member22, and to which the second roller21is rotatably attached.

The lower end of the drive shaft30is coupled to the first drive shaft51, and an upper end thereof is inserted into an insertion hole formed in the cover83. A third bearing member33that rotatably supports a tip of the first drive shaft51around the axis X1is inserted into the insertion hole of the cover83. In addition, the drive shaft30is rotatably supported around the axis X1on an inner peripheral side of the drive cylinder40by a cylindrical first bearing member31inserted along the outer peripheral surface, and a cylindrical second bearing member32formed independently from the first bearing member31.

As shown inFIG.3, the first drive unit50and the second drive unit60are housed inside a casing (a housing member)80. A gear housing unit81for housing the transmission mechanism70, and a support member90that supports the first drive unit50and the second drive unit60are attached to an inside of the casing80. In addition, the roller housing unit82for housing the first roller unit10and the second roller unit20is attached to an upper part of the casing80.

The roller housing unit82has the recess82athat houses the first roller unit10and the second roller unit20. The recess82ahas the inner peripheral surface82bformed into a circular-arc shape around the axis line X1. As shown inFIG.3, the tube101is arranged in a circular-arc shape around the axis line X1along the inner peripheral surface82b.

A first through hole that extends along the axis X1and a second through hole92that extends along an axis X2are formed in the support member90. The first drive unit50is attached to the support member90by a fastening bolt (illustration is omitted) in a state where a first drive shaft51is inserted into the first through hole91formed in the support member90. Similarly, the second drive unit60is attached to the support member90by a fastening bolt (illustration is omitted) in a state where a second drive shaft61is inserted into the second through hole92formed in the support member90. As described above, each of the first drive unit50and the second drive unit60is attached to the support member90, which is the integrally formed member.

The first drive unit50has; the first drive shaft51; the first electric motor52; and a first reducer53that reduces a velocity of rotation of a rotation shaft (illustration is omitted) rotated by the first electric motor52, and transmits the rotation to the first drive shaft51. The first drive unit50rotates the first drive shaft51around the axis X1by transmitting a drive force of the first electric motor52to the first drive shaft51.

The first roller support member12of the first roller unit10is coupled to the tip side of the drive shaft30so as to integrally rotate around the axis X1. The drive force by which the first drive unit50rotates the first drive shaft51around the axis X1is transmitted from the first drive shaft51to the first roller unit10through the drive shaft30.

The second drive unit60has; the second drive shaft61arranged on the axis X2; a second electric motor62; and a second reducer63that reduces a velocity of rotation of a rotation shaft (illustration is omitted) rotated by the second electric motor62, and transmits the rotation to the second drive shaft61. The second drive unit60rotates the second drive shaft61around the axis X2by transmitting a drive force of the second electric motor62to the second drive shaft61.

The transmission mechanism70has: a first gear unit71that rotates around the axis X2(a second axis) parallel to the axis X1; and a second gear unit72to which a drive force of the second drive shaft61is transmitted from the first gear unit71. The transmission mechanism70transmits the drive force of the second drive shaft61around the axis X2to the outer peripheral surface of the drive cylinder40, and rotates the drive cylinder40around the axis X1.

The second roller support member22of the second roller unit20is coupled to a tip side of the drive cylinder40so as to integrally rotate around the axis X1. As described above, the drive force by which the second drive unit60rotates the second drive shaft61around the axis X2is transmitted to the outer peripheral surface of the drive cylinder40by the transmission mechanism70, and is transmitted from the drive cylinder40to the second roller unit20.

Next, discharging of a liquid performed by the tube pump system700of this embodiment will be explained with reference to drawings. As shown inFIG.1, the tube pump system700of this embodiment detects a pressure of the liquid discharged from the tube pump100to the pipe200by the pressure sensor300, and transmits the pressure of the liquid to the control unit600.

In the tube pump system700shown inFIG.1, a control signal for controlling the first drive unit50and the second drive unit60of the tube pump100is transmitted from the control unit600to the tube pump100. The tube pump100may be formed as a device in which the control unit600is incorporated. In this case, the control unit600incorporated in the tube pump100generates a control signal for controlling the first drive unit50and the second drive unit60, and transmits the control signal to the first drive unit50and the second drive unit60.

FIG.4is a front view showing the tube pump100in a state where the first roller unit10reaches a closing position Po1.FIG.5is a front view showing the tube pump100in a state where the second roller unit20reaches a releasing position Po2. The closing position Po1indicates a position around the axis line X1at which a state of the first roller unit10or the second roller unit20changes over from a state of not closing the tube101to a state of closing the tube101. Further, the releasing position Po2indicates a position around the axis line X1at which a state where the first roller unit10or the second roller unit20closes the tube101is released so that a state of the first roller unit10or the second roller unit20changes over to a state of not closing the tube101. Each of the first roller unit10and the second roller unit20is independently rotated around the axis line X1in a state where the first roller unit10or the second roller unit20closes the tube101in cooperation with the inner peripheral surface82bfrom the closing position Pol to the releasing position Po2.

0°, 90°, 180° and 270° shown inFIG.4andFIG.5indicate rotation angles around the axis line X1, and indicate angles in the counterclockwise direction with the position of 0° as a reference. The closing position Po1is at a rotation angle of 50°, for example. The releasing position Po2is at a rotation angle of 310°, for example.

The first rotation angle0θ1shown inFIG.4is a rotation angle around the axis line X1formed between the first roller unit10and the second roller unit20when the first roller unit10passes through the closing position Po1. A second rotation angle θ2shown inFIG.8is a rotation angle around the axis line X1formed between the first roller unit10and the second roller unit20when the second roller unit20passes through the releasing position Po2.

Next, a process performed by the control unit600will be described.FIG.6is a flowchart showing the process performed by the control unit600to cause the tube pump100to continuously deliver a liquid at a fixed flow rate.

When power is supplied, a target flow rate Ft [ml/min] instructed by an operator is set, the control unit600starts the respective processes shown inFIG.6. The control unit600controls the first drive unit50and the second drive unit60such that the flow rate of a liquid delivered by the tube pump100agrees with the target flow rate Ft [ml/min]. The control unit600maintains the selector valve in an open state when the process shown inFIG.6is performed.

In step S101, the control unit600detects the pressure of a liquid which flows through the pipe200using the pressure sensor300. The control unit600causes the memory unit610to store a pressure detected by the pressure sensor300when the first roller unit10and the second roller unit20are rotated around the axis line X1through at least one revolution (one revolution, three revolutions, for example).

In step S102, the control unit600determines with reference to the pressure stored in the memory unit610whether or not the fluctuation ΔP of pressure when the first roller unit10and the second roller unit20are rotated around the axis line X1through at least one revolution falls within the predetermined value Pdif. When the fluctuation ΔP does not fall within the predetermined value Pdif, the control unit600advances the process to step S103. On the other hand, when the fluctuation ΔP falls within the predetermined value Pdif, the control unit600advances the process to step S105.

In step S103, the fluctuation ΔP of pressure is larger than the predetermined value Pdif and hence, the control unit600adjusts the first rotation angle θ1shown inFIG.4and the second rotation angle θ2shown inFIG.5so as to reduce the fluctuation ΔP of pressure. The reason for the adjustment of the first rotation angle θ1and the second rotation angle θ2is that a pressure difference between liquid on the downstream side of the releasing position Po2and liquid on the upstream side of the releasing position Po2is a value which corresponds to the first rotation angle θ1and the second rotation angle θ2. That is, the larger a difference between the first rotation angle θ1and the second rotation angle θ2, the higher the pressure of a liquid in the tube101which is closed by contact with the first roller unit10and the second roller unit20becomes. The smaller a difference between the first rotation angle θ1and the second rotation angle θ2, the lower the pressure of a liquid in the tube101which is closed by contact with the first roller unit10and the second roller unit20becomes.

The control unit600adjusts a control waveform based on which the first drive unit50and the second drive unit60are controlled such that the second rotation angle θ2is smaller than the first rotation angle θ1. The control waveform is adjusted as described above so as to cause a liquid which flows into the tube101at a pressure substantially equal to the atmospheric pressure to be discharged to the pipe200in a state where the pressure of the liquid is set higher than the atmospheric pressure. When the second rotation angle θ2is set smaller than the first rotation angle θ1, the pressure of a liquid discharge to the pipe200is set higher than the atmospheric pressure.

In step S104, the control unit600adjusts an angular velocity of the first roller unit10and the second roller unit20such that the flow rate per unit time of a liquid discharged to the pipe200from the end portion of the tube101is maintained at the target flow rate Ft (predetermined flow rate). The control unit600adjusts the angular velocities of the first roller unit10and the second roller unit20such that the larger the first rotation angle θ1, the lower an average angular velocity becomes, whereas the smaller the first rotation angle θ1, the higher an average angular velocity becomes. The reason the angular velocity of the first roller unit10and the second roller unit20is adjusted as described above is that the first rotation angle θ1decides the amount of liquid closed in the tube101by the first roller unit10and the second roller unit20.

The larger the first rotation angle θ1, the larger the amount of liquid which is closed in the tube101becomes. Whereas the smaller the first rotation angle θ1, the smaller the amount of liquid which is closed in the tube101becomes. The control unit600controls the angular velocity of the first roller unit10and the second roller unit20corresponding to the amount of liquid closed in the tube101, thus maintaining the target flow rate Ft (predetermined flow rate).

In step S105, the control unit600determines whether or not an instruction for change of the target flow rate Ft or end of control is provided by the operator and, if the determination is YES, the present flowchart ends the process. If the determination is NO, the control unit600repeats the process subsequent to step S101.

The process illustrated inFIG.6described above is a process performed by the control unit600to cause the tube pump100to continuously deliver a liquid at a fixed flow rate. In contrast, the process illustrated inFIG.7is a process performed by the control unit600to cause the tube pump100to intermittently deliver a liquid at a fixed flow rate.FIG.7is a flowchart illustrating a process performed by the control unit600to cause the tube pump100to intermittently deliver a liquid at a fixed flow rate.

In step S201, the control unit600performs control to maintain the state where the first drive unit50and the second drive unit60are stopped so that the tube pump100is in the stop state for not delivering the liquid.

In step S202, the control unit600controls the selector valve500into a closed state so that the selector valve500is in the blocking state where the liquid flow is blocked at the second predetermined position P2.

In step S203, the control unit600determines whether or not to start a dispensing operation to cause the liquid delivered from the tube pump100to the pipe200to be intermittently ejected by a fixed amount from the nozzle201of the pipe200and, if the determination is YES, proceeds with the process to step S204or, if the determination is NO, ends the process of the present flowchart.

In step S204, the control unit600controls the first drive unit50and the second drive unit60to operate so that the tube pump100is in the delivering state for delivering a liquid.

In step S205, the control unit600controls the selector valve500into an open state so that the selector valve500is in the flowing state where a liquid flows through the second predetermined position P2.

In step S204and step S205, the control unit600causes the delivering timing, which is to switch the state of the tube pump100from the stop state to the delivering state, and the flowing timing, which is to switch the state of the selector valve500from the blocking state to the flowing state, to be the same to synchronize the delivering timing and the flowing timing.

In step S206, the control unit600determines whether or not an operation period has elapsed from the delivering timing and, if the determination is YES, proceeds with the process to step S207or, if the determination is NO, repeats the determination of step S206. The operation period is a time period set in accordance with the amount of a liquid ejected from the other end200bof the pipe200by a single time of dispensing operation. For example, the operation period is set to be 0.3 seconds or longer and 30 seconds or shorter.

In step S207, the control unit600switches the state of the first drive unit50and the second drive unit60from the operation state to the stop state so as to switch the state of the tube pump100from the delivering state to the stop state.

In step S208, the control unit600switches the state of the selector valve500from the open state to the closed state so as to switch the state of the selector valve500from the flowing state to the blocking state.

In step S207and step S208, the control unit600causes the stop timing, which is to switch the state of the tube pump100from the delivering state to the stop state, and the blocking timing, which is to switch the state of the selector valve500from the flowing state to the blocking state, to be the same to synchronize the stop timing and the blocking timing.

In step S209, the control unit600determines whether or not to end the dispensing operation and, if the determination is YES, ends the process of the present flowchart or, if the determination is NO, proceeds with the process to step S210.

In step S210, the control unit600determines whether or not a suspension period has elapsed from the stop timing and, if the determination is YES, proceeds with the process to step S204or, if the determination is NO, repeats the determination of step S210. The suspension period is a time period set in advance in the control unit600by the input from the operator. For example, the suspension period is set to be 1 second or longer and 10 seconds or shorter.

As described above, the control unit600synchronizes the delivering timing and the flowing timing to start liquid ejection from the other end200bof the pipe200and synchronizes the stop timing and the blocking timing to stop the liquid ejection from the other end200bof the pipe200. The ejecting amount of the liquid is an amount in accordance with the operation period from the delivering timing to the stop timing. The control unit600controls the tube pump100and the selector valve500so as to repeat the operation to eject a fixed amount of a liquid from the other end200bof the pipe200until the dispensing operation ends.

According to the tube pump system700of the present embodiment described above, the following effects and advantages are achieved.

According to the tube pump system700of the present embodiment, the tube pump100intermittently pinches the tube101formed of a flexible material, and thereby a liquid in the tube101is delivered and guided to the flow channel formed inside the pipe200whose one end200ais connected to the tube101. The orifice400providing the smallest sectional area of the channel cross section in the flow channel is arranged at the first predetermined position P1in the pipe200. Since the liquid flow resistance at the orifice400is largest in the flow channel, a liquid flowing through the flow channel from one end of the pipe200to the orifice400is in a state where the dynamic pressure is lower and the static pressure is higher compared to a case where the orifice400is not provided in the flow channel.

According to the tube pump system700of the present embodiment, the tube pump100and the selector valve500are controlled so that the delivering timing at the tube pump100and the flowing timing at the selector valve are synchronized and the stop timing at the tube pump100and the blocking timing at the selector valve are synchronized. Since the stop timing at the tube pump100and the blocking timing at the selector valve are synchronized, liquid ejection from the other end200bof the pipe200is stopped in a state where the static pressure of the liquid is maintained constant between the one end200aof the pipe200and the second predetermined position P2at which the selector valve500is arranged.

Further, since the delivering timing at the tube pump100and the flowing timing at the selector valve are synchronized, liquid ejection from the other end200bof the pipe200is started in a state where the static pressure of the liquid is maintained constant between the one end200aof the pipe200and the second predetermined position P2at which the selector valve500is arranged. Since the start and the stop of the liquid ejection from the other end200bof the pipe200are switched in a state where the static pressure of the liquid is maintained constant between the one end200aof the pipe200and the second predetermined position P2at which the selector valve500is arranged, the liquid delivered from the tube pump100to the pipe200can be intermittently ejected by a fixed amount from the other end200bof the pipe200.

According to the tube pump system700of the present embodiment, the first roller part10and the second roller part20are rotated in the same direction about the axis X1by the first drive unit50and the second drive unit60, respectively, and thereby the first roller part10and the second roller part20are rotated from the closure position Pol to the release position Po2while pinching the tube101. The control unit600controls each of the first drive unit50and the second drive unit60to allow a liquid flowing in from the inflow side end101aof the tube101to be ejected from the outflow side end101bof the tube101.

The variation range of a liquid pressure determined by the pressure sensor300in at least one turn of rotation of the first roller part10represents how large the pulsation of the liquid pumped by the tube pump system700is. When the tube101that has been pinched by one of the first roller part10and the second roller part20passing through the release position Po2returns to the original shape, a larger pressure difference between the pressure of a liquid downstream of the release position Po2and the pressure of a liquid upstream of the release position Po2results in a larger variation range of the pressure. In the tube pump system700of the present embodiment, the control unit600controls each of the first drive unit50and the second drive unit60so that the pressure variation range determined by the pressure sensor300is within predetermined values. Thus, even when the state of pulsation dynamically changes, the pulsation can be suitably suppressed in accordance with the change.

According to the tube pump system700of the present embodiment, the volume of the flow channel from the first predetermined position P1to the second predetermined position P2in the pipe200is 1/10 or less of the volume from the one end200aof the pipe200to the second predetermined position P2. Thus, when the tube pump100is in the stop state and the selector valve500is in the blocking state, it is possible to suppress the flow rate of a liquid flowing out from the first predetermined position P1at which the orifice400is arranged to the second position P2at which the selector valve500is arranged. It is thus possible to suitably suppress that the pressure of the liquid in the flow channel from the one end200aof the pipe200to the orifice400is reduced and the flow rate of the liquid intermittently ejected from the pipe200is reduced accordingly.

Second Embodiment

Next, the tube pump system700according to a second embodiment of the present disclosure will be described with reference to the drawings. The second embodiment is a modified example for the first embodiment and is substantially the same as the first embodiment except for features described below, and the description of the same features will be omitted below.

The control unit600of the first embodiment causes the delivering timing at the tube pump100and the flowing timing at the selector valve500to be the same and causes the stop timing at the tube pump100and the blocking timing at the selector valve500to be the same. In contrast, the control unit600of the present embodiment defines that the timing after a first predetermined period has elapsed from the delivering timing at the tube pump100is the flowing timing at the selector valve500and the timing after a second predetermined period has elapsed from the stop timing at the tube pump100is the blocking timing of the selector valve500.

FIG.8is a flowchart illustrating a process performed by the control unit600to cause the tube pump100to intermittently deliver a liquid at a fixed flow rate in the tube pump system700according to the second embodiment of the present disclosure. Since steps except for step S304A and step S307A inFIG.8are the same as the corresponding steps inFIG.7of the first embodiment, the description thereof will be omitted below.

In step S304A, the control unit600determines whether or not a first predetermined period has elapsed from the delivering timing and, if the determination is YES, proceeds with the process to step S305or, if the determination is NO, repeats the determination of step S304A. For example, the first predetermined period is set to 10 msec or longer and 1000 msec or shorter.

In step S307A, the control unit600determines whether or not a second predetermined period has elapsed from the stop timing and, if the determination is YES, proceeds with the process to step S308or, if the determination is NO, repeats the determination of step S307A. For example, the second predetermined period is set to 10 msec or longer and 1000 msec or shorter.

As described above, the control unit600defines that the timing after the first predetermined period has elapsed from the delivering timing at the tube pump100is the flowing timing at the selector valve500and the timing after the second predetermined period has elapsed from the stop timing at the tube pump100is the blocking timing at the selector valve500. According to the tube pump system700of the present embodiment, by delaying the flowing timing by the first predetermined period from the delivering timing, it is possible to switch the state of the tube pump100from the stop state to the delivering state to increase the pressure of a liquid held in the pipe200and then switch the state of the selector valve500from the blocking state to the flowing state to increase the ejecting amount of the liquid.

Further, by delaying the blocking timing by the second predetermined period from the stop timing, it is possible to switch the state of the selector valve500from the flowing state to the blocking state to reduce the pressure of a liquid in the pipe200in the blocking state without switching the state of the tube pump100from the delivering state to the stop state to increase the pressure of the liquid held in the pipe200. Further, by suitably adjusting the first predetermined period and the second predetermined period, it is possible to adjust the ejecting amount of the intermittently ejected liquid to a suitable amount.

Third Embodiment

Next, the tube pump system700according to a third embodiment of the present disclosure will be described with reference to the drawings. The third embodiment is a modified example for the first embodiment and is substantially the same as the first embodiment except for features described below, and the description of the same features will be omitted below.

The control unit600of the first embodiment causes the delivering timing at the tube pump100and the flowing timing at the selector valve500to be the same and causes the stop timing at the tube pump100and the blocking timing at the selector valve500to be the same. In contrast, the control unit600of the present embodiment defines that the timing after a third predetermined period has elapsed from the flowing timing at the selector valve500is the delivering timing at the tube pump100and the timing after a fourth predetermined period has elapsed from the blocking timing at the selector valve500is the stop timing at the tube pump100.

FIG.9is a flowchart illustrating a process performed by the control unit600to cause the tube pump100to intermittently deliver a liquid at a fixed flow rate in the tube pump system700according to the third embodiment of the present disclosure. Since steps except for steps S404, S404A, and S405and steps S407, S407A, and S408inFIG.9are the same as the corresponding steps inFIG.7of the first embodiment, the description thereof will be omitted below.

In step S404, the control unit600controls the selector valve500into the open state so that the selector valve500is in the flowing state where a liquid flows through at the second predetermined position P2.

In step S404A, the control unit600determines whether or not a third predetermined period has elapsed from the switching timing and, if the determination is YES, proceeds with the process to step S405or, if the determination is NO, repeats the determination of step S404A. For example, the third predetermined period is set to 10 msec or longer and 1000 msec or shorter.

In step S405, the control unit600controls the first drive unit50and the second drive unit60to operate so that the tube pump100is in the delivering state for delivering a liquid.

In step S407, the control unit600switches the state of the selector valve500from the open state to the closed state so as to switch the state of the selector valve500from the flowing state to the blocking state.

In step S407A, the control unit600determines whether or not a fourth predetermined period has elapsed from the blocking timing and, if the determination is YES, proceeds with the process to step S408or, if the determination is NO, repeats the determination of step S407A. For example, the fourth predetermined period is set to 10 msec or longer and 1000 msec or shorter.

In step S408, the control unit600switches the state of the first drive unit50and the second drive unit60from the operating state to the stop state so as to switch the state of the tube pump100from the delivering state to the stop state.

As described above, the control unit600defines that the timing after the third predetermined period has elapsed from the flowing timing at the selector valve500is the delivering timing at the tube pump100and the timing after the fourth predetermined period has elapsed from the blocking timing at the selector valve500is the stop timing at the tube pump100. According to the tube pump system700of the present embodiment, by delaying the delivering timing at the tube pump100by the third predetermined period from the flowing timing at the selector valve500, it is possible to switch the state of the selector valve500from the blocking state to the flowing state to reduce the pressure of a liquid held in the pipe200and then switch the state of the tube pump100from the stop state to the delivering state to reduce the ejecting amount of the liquid.

Further, by delaying the stop timing at the tube pump100by the fourth predetermined period from the blocking timing at the selector valve500, it is possible to switch the state of the selector valve500from the flowing state to the blocking state to increase the pressure of a liquid held in the pipe200and then switch the state of the tube pump100from the delivering state to the stop state to increase the pressure of the liquid in the pipe200in the blocking state. Further, by suitably adjusting the third predetermined period and the fourth predetermined period, it is possible to adjust the ejecting amount of the intermittently ejected liquid to a suitable amount.

Other Embodiments

Although the tube pump system700is provided with the orifice400providing the smallest channel sectional area in the channel through which a liquid is guided from the tube pump100to the outflow end702in the above description, other forms may be employed. For example, a needle valve providing the smallest channel sectional area in the channel through which a liquid is guided from the tube pump100to the outflow end702may be provided instead of the orifice400. The channel sectional area of the needle valve can be changed within a predetermined range.