GB2317925A

GB2317925A - Peristaltic pump

Info

Publication number: GB2317925A
Application number: GB9620888A
Authority: GB
Inventors: John Nicholas James Watkins
Original assignee: VICTOR PYRATE Ltd
Current assignee: VICTOR PYRATE Ltd
Priority date: 1996-10-07
Filing date: 1996-10-07
Publication date: 1998-04-08
Also published as: AU4567797A; WO1998015737A1; GB9620888D0

Abstract

A hand-held peristaltic pump 10 comprises a plastic moulded housing 11 in which is mounted a length of elastically deformable plastic tubing 12 which passes through the housing such that ends 12a and 12b of the tube emerge at opposite sides of the housing 11. The tube passes between a battery driven electric rotor 15 and a stationary clamp 16. The clamp 16 is mounted in the housing 11 such that it may slide along an axis parallel to line A-A' of Figure 1. The clamp 16 is biased towards the position shown in Figure 1 by a stainless steel leaf spring 18 and may be manually displaced therefrom by depressing a pair of pivoting arms 19 located on opposed sides of the housing 11, for example to enable the tube to be flushed.

Description

PERISTALTIC PUMP AND METHOD The present invention relates to a peristaltic pump and to a method of operating such a pump.

Peristaltic pumps have been widely used for many years in scientific, medical and industrial applications.

An advantage of using a peristaltic pump, as opposed to other types of pump, is that of hygiene - the fluid being pumped comes into contact only with the tubing through which it passes, and does not contact the pump itself, thereby reducing the risk of contamination of the fluid.

For this reason, the use of peristaltic pumps is preferred in many medical applications, such as the pumping of blood when, for example, a patient's blood sample is being taken.

Previous known peristaltic pumps comprise a free standing housing which contains a mains-powered electric motor to drive a rotor, and a cartridge containing a length of tube which is squeezed by a succession of rollers mounted on the rotor, thereby to trap the fluid in the tube and pump it along the tube. An example of a known peristaltic pump is described in our UK Patent N" 1578022.

However, when for example such a pumping apparatus is used in removing samples of blood from a bed-bound patient it is inconvenient to use the known type of relatively bulky, mains powered, free standing apparatus. In addition, in this type of application it is often necessary to flush the tube with saline solution after each sample of blood is taken. Such a flushing operation is difficult in the known peristaltic pump, as it may require dismantling of at least part of the pump to free the tube from engagement with the rollers.

Accordingly, specific embodiments of the present invention aim to provide a peristaltic pump apparatus in which at least some of the aforementioned disadvantages are at least partially overcome.

According to the invention there is provided peristaltic pumping apparatus comprising an elastically deformable tube through which fluid is pumped in use, a rotatable member having at least one bearing portion arranged in use to bear on and traverse at least part of the length of the tube as the rotatable member rotates and a support member located on the side of the tube opposed to the rotatable member, so that the tube passes between the support member and the rotatable member, wherein at least one of the support member and the rotatable member is movable between a first position in which the tube is squeezed between the bearing portion and the support member as the bearing portion traverses the tube, thereby in use to cause fluid in the tube to be pumped therethrough, and a second position in which the support member is further from the bearing portion of the rotatable member as it traverses the tube than in the first position, wherein movement of the moveable member from the first position to the second position is effected by relative movement towards each other of two portions of the apparatus.

In a preferred arrangement the moveable member comprises the support member.

Preferably the apparatus is arranged to be operated manually such that the relative movement of the two portions may be effected in use by a single hand.

Preferably there is provided biasing means for bias the moveable member towards the first position.

The invention also includes a method of flushing a tube of a peristaltic pumping apparatus, the method comprising releasing the tube from occlusion between a rotatable member and a support member by moving at least one of the support member and the rotatable member from a first, occluding, position to a second, non-occluding, position, movement of the moveable member being effected by relative movement towards each other of two portions of the apparatus, and flushing the tube with cleaning fluid.

Other features of the invention are set out in the appended claims.

The invention may be carried into practice in various ways. An embodiment will now be described by way of example only with reference to the accompanying diagrammatic drawings in which: Figure 1 is a front view of a peristaltic pump according to a preferred embodiment of the invention; Figure 2 is a sectional view taken along the line A A' of Figure 1; Figure 3 is a front view of an upper part of the pump of Figures 1 and 2, in an alternative configuration; and Figure 4 is a rear view of the pump of Figures 1 to 3.

Referring particularly to Figure 1, there is shown generally at 10 a hand-held peristaltic pump. The pump 10 comprises a plastic moulded housing 11 in which is mounted a length of elastically deformable plastic tubing 12 which passes through the housing, such that ends 12a and 12b of the tube 12 emerge at opposite sides of the housing 11.

The tube 12 is secured in the housing by means of plastic clips 13 and 14 which are attached to the tube at respective ends 12a, 12b thereof, and which locate in corresponding mounting points lla, llb in the housing.

The tube 12 passes between a battery driven electric rotor 15 and a stationary clamp 16. The clamp 16 has an arcuate portion 16a against which the tube 12 rests in use. The clamp 16 is mounted in the housing 11 such that it may slide along an axis parallel to line A-A' of Figure 1, between an operating position shown in Figure 1 and a non-operating position, spaced from tube 12, which is shown in Figure 3. The clamp 16 is biased towards the position shown in Figure 1 by a stainless steel leafspring 18 which ensures that the clamp 16 always bears against the tube 12 with a substantially constant pressure, and may be manually displaced therefrom by depressing a pair of pivoting arms 19 located on opposed sides of the housing 11. When depressed inwardly, with respect to the housing 11, the arms pivot about integrally moulded spindle 20, causing portions l9a of the arms to push against clamp 16 at locations 16b, which in turn cause the clamp 16 to slide away from the tube 12, against the spring 18 to a maximum position at which the clamp 16 abuts end stop llc. When arms 19 are released the spring 18 returns the clamp 16 to the position shown in Figure 1.

The rotor 15, clamp 16, portions 19a of the arms and the portion of the tube 12 between the clamp 16 and rotor 15 are all enclosed in the housing 11 by a transparent plate 21 of polycarbonate material slideably mounted on the housing. At the foot of the housing is located an onoff switch 22 and an indicator lamp 23 which indicates a low charging condition of a battery (described in relation to Figure 2).

Turning to Figure 2, this shows the pump of Figure 1 in sectional view taken along the line A-A' of Figure 1.

Figure 2 shows a rear chamber lld of the housing 11 in which is mounted an electric motor and gearbox 24. In use the motor and gearbox drives a spindle 25 which passes through wall lle and on which the rotor 15 is mounted in a forward chamber llf. The motor 24 is preferably a 6-volt DC motor whose gearbox is arranged to drive the rotor at 40 r.p.m. maximum and is powered by a battery 26. Access to the battery 26 and the motor and gearbox 24 is through a detachable rear panel 27 which is mounted on the housing by means of two screws (shown in Figure 4). A printed circuit board 28 for controlling the motor 24 is mounted below the battery 26. The plate 21 is shown in broken lines in Figure 2, depicting the position to which it may be slid, for access to the tube and motor.

Figure 3 shows part of the pump 10 in the same view as Figure 1. In Figure 3 the clamp 16 is in its nonoperative position, spaced from the tube 12, the arms 19 having been depressed inwardly thereby causing the clamp 16 to slide against the action of the spring 18.

Figure 4 shows the pump in rear view, with part of the rear panel 27 cut away to reveal the motor and gear box 24, the battery 26 and the printed circuit board 28.

Figure 4 shows fixing screws 29 which are used for securing the rear panel 27 to the housing 11.

Other features shown in Figure 4 are a battery retaining clip 30 which holds the battery 26 in place, and an anchorage clip 31 at the top of the pump, for attaching the pump to a mounting point, such as a rail (not shown).

The tube 12 is inserted into the housing 11 by first removing the top plate 21, and then depressing inwardly the arms 19 so that the clamp 16 adopts the position shown in Figure 3. Firstly, clip 13 at the input end of tube 12 is located in the mounting point 11a of housing 11. Then the tube 12 is fed around the rotor 15. The clip 14, at the output end of the tube 12, is then located in the mounting point 11b of the housing 11. The arms 19 are then released, allowing the clamp 16 to return to the position shown in Figure 1, and the top plate 21 is replaced. The pump is then ready for use.

Referring to all of the Figures 1 to 4, an operation of the pump 10 will now be described.

As the rotor 15 rotates, each of the rollers 17 traverses in turn a portion of the tube 12 causing the tube to be occluded, i.e. each location on the portion of tube is sequentially squeezed by the succession of rollers 17. As each roller meets the tube, the tube becomes occluded and recovers its shape by elastic memory after the roller has passed. Fluid (not shown) in the tube 12 is therefore driven along the tube in advance of the roller, and as the tube re-opens behind the roller the partial vacuum thus created draws more fluid into the tube. In this way fluid is drawn into an inlet side 12a of the tube and pumped out of an outlet side 12b of the tube. The rate at which the fluid is pumped, for a given tube diameter, varies with the speed of rotation of the rotor 15.

An example of typical use of the pump 10 is that of taking samples of a patient's blood for analysis. In order to do this the input end 12a of the tube 12 is connected to a patient's bloodstream (not shown) and the output end 12b of the tube 12 is connected to a portable computerised analyser (not shown). A bag of saline solution (not shown) is also connected to the input tube 12, via a suitable valve (not shown) for the purpose of cleaning the tube 12.

After each sample of blood is pumped from the patient to the analyser, the tube 12 must be cleaned. This is achieved by flushing the tube with saline solution. In order to allow flushing of the tube 12 with saline solution the arms 19 of the pump 10 are depressed inwardly causing the clamp 16 to move away from the tube 12. The tube is then no longer occluded between the clamp 16 and rollers 17, thereby allowing the free flow of cleaning saline solution therethrough. In this configuration, no pumping will take place even if the rotor 15 is made to turn.

When the tube 12 has been flushed, the arms 19 are released and the pump is again ready to operate normally.

An advantage of the pump 10 over prior known peristaltic pumps is the ease with which it may be used.

A user may operate the pump by holding it in one hand, and may facilitate flushing of the tube readily for example by depressing arms 19 with the finger and thumb of one hand and turning a tap or valve connected to a source of saline solution with the other hand without dismantling the pump 10 to remove the tube 11.

If it is required to remove the clamp 16 and spring 18 for cleaning, the top plate 21 is first slideably moved and the arms 19 may then be lifted out of their pivotal engagement in the housing. The rotor 15 is then be lifted from its engagement with the spindle 25 and the clamp 16 and spring 18 may then be removed.

Claims

CLAIMS:

1. Peristaltic pumping apparatus comprising an elastically deformable tube through which fluid is pumped in use, a rotatable member having at least one bearing portion arranged in use to bear on and traverse at least part of the length of the tube as the rotatable member rotates and a support member located on the side of the tube opposed to the rotatable member, so that the tube passes between the support member and the rotatable member, wherein at least one of the support member and the rotatable member is movable between a first position in which the tube is squeezed between the bearing portion and the support member as the bearing portion traverses the tube, thereby in use to cause fluid in the tube to be pumped therethrough, and a second position in which the support member is further from the bearing portion of the rotatable member as it traverses the tube than in the first position, wherein movement of the moveable member from the first position to the second position is effected by relative movement towards each other of two portions of the apparatus.

2. Apparatus according to Claim 1, in which the moveable member is the support member.

3. Apparatus according to Claim 1 or 2, in which at least one of the said two portions comprises an actuator.

4. Apparatus according to any of Claims 1 to 3, wherein the apparatus is arranged to be operated manually such that the relative movement of the two portions may be effected in use by a single hand.

5. Apparatus according to Claim 1 or Claim 2, wherein the two portions comprise two actuators which are operable by movement towards each other.

6. Apparatus according to any of Claims 1 to 5, including biasing means which are arranged to bias the moveable member towards the first position.

7. Apparatus according to Claim 5, wherein the actuators comprise pivotal arms bearing at one end on the support member and pivotable by movement towards each other of their other ends to move the support member from the first to the second position.

8. Apparatus according to any of the preceding claims arranged in use to be hand-held.

9. Apparatus according to any of the preceding claims wherein the rotatable member comprises six bearing portions.

10. Apparatus according to Claim 9, wherein the bearing means comprise rollers.

11. Apparatus according to any of the preceding claims wherein the rotatable member is driven by a battery powered electric motor.

12. A method of flushing a tube of a peristaltic pumping apparatus, the method comprising releasing the tube from occlusion between a rotatable member and a support member by moving at least one of the support member and the rotatable member from a first, occluding, position to a second, non-occluding, position, movement of the moveable member being effected by relative movement towards each other of two portions of the apparatus.

13. A method according to Claim 12, in which the movement of the support member from the first to the second position is manual, and is achieved by causing movement towards each other of the two portions which portions comprise actuating members.

14. Peristaltic pumping apparatus substantially as herein described with reference to the accompanying drawings.

15. A method of flushing a tube of a peristaltic pumping apparatus, the method being substantially as herein described with reference to the accompanying diagrammatic drawings.