GB2538556A

GB2538556A - Peristaltic pump

Info

Publication number: GB2538556A
Application number: GB1508785.1A
Authority: GB
Inventors: Samuel Skelton Christopher
Original assignee: VERDER Ltd
Current assignee: VERDER Ltd
Priority date: 2015-05-22
Filing date: 2015-05-22
Publication date: 2016-11-23
Anticipated expiration: 2035-05-22
Also published as: GB2538556B; GB201508785D0

Abstract

A peristaltic pump 1 comprises a peristaltic rotor assembly 3, a cover 5 for the rotor assembly, the cover being moveable between a first position in which the rotor assembly is shielded from access and a second position in which the rotor assembly is, a switch 7 biased towards a non-actuated configuration, and a control unit operatively associated with both the cover and the switch, said control unit being configured for controlling a drive arrangement for effecting rotation of the rotor assembly. When the cover is in the first position the rotor assembly rotates at a pumping speed irrespective of the configuration of the switch. When the cover is in the second position the rotor assembly rotates at an installation speed. When the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly.

Description

Peristaltic Pump The present invention relates to peristaltic pumps. The invention relates more particularly, but not necessarily exclusively, to peristaltic pumps having improved safety features.

Peristaltic pumps operate by means of a rotor assembly which, when rotating, is configured to compress periodically a flexible walled elongate conduit in the form of a tube against a complementary surface and along the length of the tube to apply a peristaltic action thereto.

During operation of such a pump, objects (such as body parts) can inadvertently become trapped in the rotor assembly, hence presenting a safety hazard. In order to mitigate such a hazard rotor assemblies are often provided with covers which are capable of shielding their rotating parts from access and thereby reducing the risk of objects becoming trapped inside.

During typical usage of a peristaltic pump, it may be necessary to perform maintenance work on the rotor assembly, particularly on the tube component thereof. Such maintenance may, for example, take the form of removal and re-installation of the tube to facilitate cleaning. Maintenance can be difficult, particularly in larger peristaltic pumps (such as those used for pumping concrete or sewage) which utilise correspondingly large tubes and rotor assemblies.

Access to the rotating parts of the rotor assembly is useful and often necessary when conducting pump maintenance. In terms of tube maintenance, for example, access enables an operator to ensure that the tube is correctly positioned within the device during installation. In order to enable such access, the cover may be in the form of a hinged door which can be repositioned, when required, for access to the moving parts.

Such doors may be provided with a detector configured to stop rotation of the assembly if the door is so repositioned (or otherwise removed), thereby further mitigating operating hazards.

Rotation of the rotor assembly can cause migration of the tube during normal use and so tubes are generally clamped in place in order to prevent such migration. Tube migration can, however, be useful in facilitating tube maintenance. In particular, rotation of the rotor assembly can be used to draw a tube into the rotor assembly during tube installation, or to eject a tube during tube removal. However, if the pump utilises a cover which is designed to stop rotation of the rotor assembly if the cover is removed, then clearly tube migration cannot be used to facilitate tube replacement while concurrently enabling access to the rotating parts.

It is an object of the present invention to obviate or mitigate the abovementioned disadvantages and to provide an improved peristaltic pump.

According to a first aspect of the present invention there is provided a peristaltic pump comprising: (i) a peristaltic rotor assembly; (H) a cover for the rotor assembly, the cover being moveable between a first position in which the rotor assembly is shielded from access and a second position in which the rotor assembly is accessible to an operator thereof; (Hi) an actuatable switch biased towards a non-actuated configuration; and (iv) a control unit operatively associated with both the cover and the switch, said control unit being configured for controlling a drive arrangement for effecting rotation of the rotor assembly; wherein, when the cover is in the first position, the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at a pumping speed irrespective of the configuration of the switch; when the cover is in the second position, and the switch is actuated, the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at an installation speed; and when the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly.

The present invention provides a convenient solution to the aforementioned disadvantages relating to pump maintenance and safety. Essentially, the pump of the present invention is configured to operate in three different modes: Pumping: This mode is entered when the cover is in the first (shielding) position.

In this mode, the control unit is able to cause the rotor assembly to rotate at a pumping speed, while the cover shields access to the rotating parts of the rotor assembly so that there is diminished risk of objects (e.g. body parts) becoming trapped inside. The pump is typically provided with tube clamping arrangement configured to grip a tube of the peristaltic pump in order to prevent tube migration during pumping mode.

Safe: This mode is entered when the cover is in a second (access) position and the switch is not actuated and includes the situation where the switch was actuated, but is subsequently released, and returned to a non-actuated configuration. In this mode, the position of the cover enables access to the rotor assembly for maintenance. Additionally, the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly. Such prevention includes the situation where the drive arrangement was rotating the rotor assembly, in which situation the drive arrangement is caused to cease further rotation; and also includes the situation where the drive arrangement was not rotating the rotor assembly, in which situation the drive arrangement is prevented from rotating the rotor assembly. As a result, the risk of objects becoming trapped in the rotor assembly's rotating parts is mitigated.

Installation: This mode is entered when the cover is in the second (access) position and the switch is actuated. In this mode, the position of the cover enables access to the rotor assembly for maintenance. Additionally, the rotor assembly is able to rotate at an installation speed to facilitate tube maintenance by virtue of actuation of the switch. Rotation at an installation speed is useful for a number of reasons. The rotating action can, for example, be used to draw a tube into the rotor assembly during tube installation, and/or to eject a tube during tube removal. Due to the biased nature of the switch, continuous actuation is required in order maintain the pump in this mode. In this way, the switch operates as a "dead man's switch", automatically returning the pump to the safe mode in the event of incapacitation of the operator. When installing the tube of the pump any tube clamping arrangement should be disengaged to enable tube movement/migration.

The pump of the present invention therefore provides a convenient means by which a peristaltic pump may be operated in a safe manner, while also facilitating maintenance of the rotor assembly comprised therein.

Conveniently, the peristaltic pump of the present invention may be supplied as a complete pumping unit together with the drive train arrangement for effecting rotation thereof. In other words, according to a second aspect of the present invention there is provided a peristaltic pump comprising: (i) a peristaltic rotor assembly; (H) a drive arrangement for effecting rotation of the peristaltic rotor assembly; (Hi) a cover for the rotor assembly, the cover being moveable between a first position in which the rotor assembly is shielded from access and a second position in which the rotor assembly is accessible to an operator thereof; (iv) an actuatable switch biased towards a non-actuated configuration; and (v) a control unit operatively associated with both the cover and the switch, said control unit being configured for controlling the drive arrangement; wherein when the cover is in the first position the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at a pumping speed irrespective of the configuration of the switch; when the cover is in the second position and the switch is actuated, the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at an installation speed; and when the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly.

The cover, switch and control unit may be supplied as a kit of parts for retrofitting to an existing peristaltic pump. To that end, according to a third aspect of the present invention there is provided a kit of parts for fitting to a peristaltic pump that comprises a rotor assembly, the kit comprising: (i) a cover for the rotor assembly which, when fitted to the pump, is moveable between a first position in which the rotor assembly is shielded from access and a second position in which the rotor assembly is accessible to an operator thereof; (H) an actuatable switch biased towards a non-actuated configuration; and (Hi) a control unit operatively associated with both the cover and the switch, said control unit being configured for controlling a drive arrangement of the peristaltic pump for effecting rotation of the rotor assembly; wherein when fitted to the pump, when the cover is in the first position the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at a pumping speed irrespective of the configuration of the switch; when the cover is in the second position, and the switch is actuated, the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at an installation speed; and when the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly.

Preferred features common to both the first, second and third aspects of the present invention are described below.

In the practice of the invention, when the pump is in its "safe-mode", the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly. When in this mode, although not actively driven, the rotor assembly may nevertheless be permitted to rotate (i.e. to "free-wheel") if desired, for example by being turned manually by an operator of the pump. Manual rotation may be useful for assisting in pump maintenance, such as for feeding a replacement tube into the rotor assembly during tube installation.

It will be appreciated that permission of manual rotation may not be desired in some instances. As a result, when the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit may be configured to prevent the rotor assembly from rotating. Prevention of rotation may be effected by any suitable means well known to those of skill in the art. The rotor assembly may, for example, be provided with one or more brakes operatively associated with the control unit such that, when in "safe-mode", the one or more brakes is/are configured to prevent the rotor assembly from rotating.

Peristaltic pumps may be configured to pump fluids at numerous different speeds. In some instances the pump may operate relatively quickly to maximise fluid displaced thereby. Such speeds of operation may be too fast to facilitate careful installation and ejection of a tube during maintenance. Accordingly, in certain embodiments the installation speed may be slower than the pumping speed. In other instances, it may be desirable to operate the pump relatively slowly in pumping mode, for example in applications where only a relatively small quantity of fluid displacement is required.

Such speeds of operation may be too slow for efficient installation of a tube. Accordingly, in further embodiments the installation speed may be faster than the pumping speed. In still further embodiments, the installation speed may be the same as the pumping speed. The installation speed is preferably between 1 and 20 rpm.

The specific installation speed selected will likely depend on the application and may also depend on the size of the tube for installation.

In preferred embodiments of the invention the peristaltic pump and/or kit further comprise a speed control member, the speed control member being operatively associated with the control unit to enable adjustment of the pumping and/or installation speed(s) as desired.

The peristaltic pump may be configured such that, when the pump is in the installation mode, the rotor can be selectively caused to rotate in either a forwards or backwards (reverse) direction. The rotor may, for example, be selectively rotatable in either a clockwise or a counter clockwise direction. It will be appreciated that operating the rotor in a "forwards" direction is useful for feeding a tube into the rotor assembly. Conversely, operating the rotor in a "backwards" (or "reverse") direction may be useful for tube ejection.

Selective forward and backwards rotation may be achieved in a number of ways. The aforementioned ("first") actuatable switch may be configured to enable rotation of the rotor in a "forwards" direction and the pump may be provided with a second actuatable switch configured to enable rotation of the rotor in the backwards direction. The switches may be actuated independently of each other, actuation of the first switch being used to enable rotation in a forwards direction, and actuation of the second switch being used to enable rotation in a backwards direction.

Alternatively, the switches may be configured to operate in conjunction with one another. In particular, actuation of the first switch may cause the rotor to run at an installation speed in a default direction (e.g. in the forwards direction). Actuation of the second switch concurrently with the first switch may cause the rotor to run in a direction opposite to this default direction (e.g. in the reverse direction). The second switch may be in the form of a toggle switch configured to toggle the default direction of rotation upon actuation of the first switch between a forwards or backwards direction. Other configurations will be apparent to those of skill in the art.

Movement of the cover between the first and second positions may be detected by means of a detector, the detector being able to be triggered when the cover moves between the first and second positions and thereby enabling the control unit to switch between the abovementioned operational modes. Suitably, the detector could comprise electronic components, such as a reed switch and magnet or electromagnetic coil, an inductive proximity sensor, an optical sensor, and/or a pressure plate. Many other suitable detection means are well known to those skilled in the art.

The operative association between the control unit and the cover and/or the control unit and the actuatable switch may be achieved through signalling devices associated with those components, said devices enabling one or more signals to be sent between said components to indicate their state. The actuatable switch might, for example, be provided with a signalling device configured to signal the control unit to convey information relating to the actuated or non-actuated state of that switch. Similarly, the cover may be provided with a signalling device configured to convey information relating to the position of the cover (i.e. whether it is in the first or second position). By extension, the control unit may be configured to process signals to determine whether to switch between the aforementioned operational modes.

Signalling devices may be useful for effecting operative association and/or control of various components of the pump and/or kit. Conveniently, for example, control of the drive arrangement may be achieved by means of one or more signals sent from the control unit. The control unit may, for example, be configured to send (i) a pumping mode signal for controlling the drive arrangement to cause the rotor assembly to rotate at a pumping speed; (H) an installation signal for controlling the drive arrangement to cause the rotor assembly to rotate at an installation speed; and/or (Hi) a stop signal for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly.

Other signals which may be usefully conveyable by the components of the pumps and/or kit of the present invention will be apparent based on the preceding and forthcoming description. Generally speaking, signals may be used to indicate the state, or control the behaviour, of any suitable component of the pumps of the present invention. For example, in accordance with embodiments of the invention in which the control unit is configured for controlling the drive arrangement to prevent rotation of the rotor assembly when the cover is in the second (access) position, a further signal may comprise a prevention signal for effecting such control.

Depending on the application, movement between the first (shielding) position and the second (access) position may be characterised in terms of only a slight movement of the cover. Such a slight movement may, for example, be of the order of the size of a human finger in applications where it is important to shield an operator's fingers from the moving parts. The pump may, therefore, be configured such that it is only necessary to move the cover by about 5 to 10 cm to move between the first (shielding) and second (access) positions. In other instances, however, repositioning the cover in the second (access) position may require a more substantial movement from the first (shielding) position. The operative association between the cover and the control unit should be adequately configured having due regard to that which is to be shielded in the circumstances.

For convenience, the cover is preferably attachable to the rotor assembly. In particularly preferred embodiments, the cover may be hingedly attached to the rotor assembly, said cover being able to move between said first (shielding) and second (access) positions by pivoting about said hinge. Such a hingedly attached cover may conveniently be in the form of a door. In other preferred embodiments, the cover may simply clip onto the rotor assembly, said cover being in the first (shielding) position when clipped onto the assembly, and in the second (access) position when unclipped from the assembly. Other configurations of cover design will be apparent to those skilled in the art.

The switch may take the form of a miniature snap-action switch (also known as a micro switchTm), toggle switch, button, lever, foot pedal and/or dial. Many other suitable switch designs are well known to those skilled in the art.

For a better understanding, the present invention will now be more particularly described, by way of non-limiting example only, with reference to and as shown in the accompany schematic drawings (not necessarily to scale) in which: Fig. 1 is a schematic perspective view of an embodiment of the peristaltic pump of the present invention; and Fig. 2 is a further schematic perspective view of the pump shown in Fig. 1.

Referring to Figs. 1 and 2, there is shown therein an embodiment of pump according to the present invention in the form of a complete pumping unit 1, the unit 1 comprising a peristaltic rotor assembly 3 and a drive arrangement (not labelled, the drive arrangement being encased within the pump unit 1 and therefore not visible in the figure) for effecting rotation of the rotor assembly 3.

Pump unit 1 is provided with a cover in the form of a door 5 for shielding the rotor assembly 3 from access and thereby mitigating risks in relation to objects (for example body parts) becoming trapped inside. Pump unit 1 further comprises an actuatable switch 7. Both the door 5 and the switch 7 are operatively associated with a control unit in the form of electrical circuitry (not labelled) provided within the pump unit 1 (and therefore not visible in the figure). The control unit is configured to cause the drive arrangement to enter different operational modes depending on the position of the door 5 and the actuation state of the switch 7, as described more fully below.

Pump unit 1 is a generally cuboid shaped box structure having major upper and lower sides. A frontal face 9 of the unit is vertically divided into two sections. A right-hand section 9a of the frontal face is comprised of the rotor assembly 3 and a left-hand section 9b is comprised of a control panel 11 incorporating said actuatable switch 7.

The door 5 shielding the rotor assembly 3 is generally square-shaped and attached to the pump unit 1 by means of a pair of hinges 5a provided along a vertical edge of the door 5. The door 5 is attached to a left-most vertical edge of the right-hand section 9a of the pump unit's frontal face. The hinges 5a enable access to the rotor assembly 3, when desired, by enabling the door 5 to pivot between open (rotor assembly-accessible) and closed (rotor assembly-shielded) positions. The door 5 is shown in an open position in Fig. 1, and in a closed position in Fig. 2.

The door 5 comprises a locking tab 13 located mid-way down its right-most vertical edge, said tab 13 projecting outwardly from the door 5 at an angle perpendicular to the door's plane at a side thereof such that the tab projects towards the pumping unit 1 when the door 5 is in the closed position. The tab 13 is provided with a pin (not labelled/visible in the Figures) which is able to interact with a correspondingly shaped slot 15 in the pump unit 1 to retain the door 5 in place when in the closed (rotor assembly-shielded) position. In addition to the aforementioned retaining function of the pin and slot 15, these components, together, also function as a detector for detecting the position of the door 5. In particular, the pin and slot 15 behave as a pressure plate detector which is activated when the door 5 is in the closed position. The detector is able to signal the control unit to convey information relating to the position of the door 5 and thereby provides the aforementioned operative association of the door 5 with the control unit.

The actuatable switch 7 of the control panel 11 is biased towards a non-actuated configuration and is configured to signal the control unit to convey information relating to the actuated or non-actuated state of that switch 7, thereby providing the aforementioned operative association with the control unit.

The control panel further comprises, in addition to the actuatable switch 7, a power button 17 for toggling the pump unit between an "on" or "off" state and a display 19 for displaying information relating to the pumping speed of the pump unit 1.

As shown in Fig. 2 only, the rotor assembly 3 is provided with two tube clamps 21 which are capable of restricting movement of a tube provided therein (tube not shown) and thereby preventing tube migration during pumping. For clarity, the tube clamps 21 are not shown in Fig. 1.

In use, the signals sent by the door 5 and switch 7 to the control unit enable the pump unit 1 to operate in three different modes: Pumping: This mode is entered when the door 5 is in the first (shielding) position as shown in Fig. 2. In this mode, the control unit is configured for controlling the drive arrangement to cause the rotor assembly 3 to rotate at a pumping speed, while the door 5 shields access to the rotating parts of the rotor assembly 3 so that there is diminished risk of objects (e.g. body parts) becoming trapped inside.

Safe: This mode is entered when the door 5 is in a second (access) position as shown in Fig. 1 and the switch 7 is not actuated. In this mode, the position of the door 5 enables access to the rotor assembly 3 for maintenance. Additionally, the control unit is configured for controlling the drive arrangement to prevent it from rotating the rotor assembly 3. Such prevention includes the situation where the drive arrangement was rotating the rotor assembly, in which situation the drive arrangement is caused to cease further rotation; and also includes the situation where the drive arrangement was not rotating the rotor assembly, in which situation the drive arrangement is prevented from rotating the rotor assembly. As a result, the risk of objects becoming trapped in the rotating parts of the rotor assembly 3 is mitigated.

Installation: This mode is entered when the door 5 is in the second (access) position as shown in Fig. 1 and the switch 7 is actuated. In this mode, the position of the door 5 enables access to the rotor assembly 3 for maintenance. Additionally, the control unit is configured for controlling the drive arrangement to cause the rotor assembly 3 to rotate at an installation speed to facilitate tube maintenance. Rotation at an installation speed is useful for a number of reasons. The rotating action can, for example, be used to draw a tube into the rotor assembly 3 during tube installation, and/or to eject a tube during tube removal. The tube clamps 21 should be removed during such installation operations, since otherwise movement of the tube would be restricted. Due to the biased nature of the switch 7, continuous actuation is required in order maintain the pump unit 1 in this mode. In this way, the switch 7 operates as a "dead man's switch", automatically returning the pump unit 1 to the safe mode in the event of incapacitation of the operator.

Claims

CLAIMS: 1. A peristaltic pump comprising: (i) a peristaltic rotor assembly; (H) a cover for the rotor assembly, the cover being moveable between a first position in which the rotor assembly is shielded from access and a second position in which the rotor assembly is accessible to an operator thereof; (Hi) an actuatable switch biased towards a non-actuated configuration; and (iv) a control unit operatively associated with both the cover and the switch, said control unit being configured for controlling a drive arrangement for effecting rotation of the rotor assembly; wherein, when the cover is in the first position, the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at a pumping speed irrespective of the configuration of the switch; when the cover is in the second position, and the switch is actuated, the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at an installation speed; and when the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly.
2. The peristaltic pump according to claim 1, wherein the operative association between the control unit and the cover is provided through means of a detector, the detector being triggerable when the cover moves between the first and second positions.
3. The peristaltic pump according to claim 2, wherein the detector comprises a reed switch and magnet or electromagnetic coil, an inductive proximity sensor, an optical sensor, and/or a pressure plate.
4. The peristaltic pump according to any preceding claim, wherein the cover is attachable to the rotor assembly.
5. The peristaltic pump according to claim 4, wherein the cover is hingedly attached to the rotor assembly, said cover being able to move between said first and second positions by pivoting about said hinge.
6. The peristaltic pump according to any preceding claim, wherein the installation speed is slower than the pumping speed.
7. The peristaltic pump according to any preceding claim, wherein the installation speed is between 1 and 20 rpm.
B. The peristaltic pump according to any preceding claim, further comprising a speed control member, the speed control member being operatively associated with the control unit to enable adjustment of the pumping and/or installation speed(s).
9. The peristaltic pump according to any preceding claim, wherein when the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit is configured to prevent the rotor assembly from rotating.
10. The peristaltic pump according to any preceding claim further comprising a drive arrangement for effecting rotation of the rotor assembly.
11. The peristaltic pump according to any preceding claim wherein the rotor can be selectively caused to rotate in either a forwards or backwards (reverse) direction.
12. The peristaltic pump according to claim 11, further comprising an additional actuatable switch configured to enable switching rotation of the rotor between the forwards and backwards (reverse) directions.
13. A peristaltic pump substantially as hereinbef ore described with reference to the accompanying Figures.
14. A kit of parts for fitting to a peristaltic pump that comprises a rotor assembly, the kit comprising: (i) a cover for the rotor assembly which, when fitted to the pump, is moveable between a first position in which the rotor assembly is shielded from access and a second position in which the rotor assembly is accessible to an operator thereof; (H) an actuatable switch biased towards a non-actuated configuration; and (Hi) a control unit operatively associated with both the cover and the switch, said control unit being configured for controlling a drive arrangement of the peristaltic pump for effecting rotation of the rotor assembly; wherein when fitted to the pump, when the cover is in the first position the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at a pumping speed irrespective of the configuration of the switch; when the cover is in the second position, and the switch is actuated, the control unit is configured for controlling the drive arrangement to cause the rotor assembly to rotate at an installation speed; and when the cover is in the second position and the switch remains in or returns to its non-actuated configuration, the control unit is configured for controlling the drive arrangement to prevent it from rotating or further rotating the rotor assembly.