[0001] The present invention relates to burettes and more particularly but not exclusively to medical burettes used to administer intravenous liquids.

BACKGROUND

[0002] Medical burettes are used to control the flow of liquid to be supplied to a patient intravenously. Frequently burettes can be provided with an injection port via which a further liquid (medication) may be introduced into the burette for delivery to the patient.

[0003] The further liquid may also be delivered via a septum or like device.

[0004] Known burettes are described in USA Patent 5885532 and Australian Patent

2006301931.

[0005] Disadvantages in respect of the above discussed burettes include not fully draining from the injection port the second liquid (medication), the generally complex of their construction, and frequently requiring additional clamps to restrict the flow of fluid.

[0006] A yet further disadvantage is the complexity of operation, making it difficult for medical professionals to correctly operate the burettes and associated clamps when compared with the operation of standard (ISO 8536-5) burettes.

OBJECT

[0007] It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages. SUMMARY

[0008] There is disclosed herein a burette including:

a hollow body providing a primary liquid inlet, a generally upright longitudinal axis, and enclosing a chamber to receive a liquid, a chamber first inlet and a chamber second inlet, and a chamber outlet;

a first valve, the valve being operatively associated with the first chamber inlet to close the first chamber inlet when liquid in the chamber exceeds a predetermined level; and

a second valve, the second valve being operable to provide a first passage joining the primary inlet and the first chamber outlet, and a second passage joining the primary inlet and said second chamber inlet.

[0009] Preferably, said second valve is operable to provide a third passage, the third passage connecting the injection port with said chamber.

[0010] Preferably, said second valve is operable to provide a fourth passage, said fourth passage providing a vent connecting the chamber atmosphere.

[0011] Preferably, said second and third passages communicate with said chamber via said second chamber inlet. ·

[0012] Preferably, said second valve includes a movable valve member eatable in a plurality of positions, the positions corresponding to said passages.

[0013] Preferably, said movable valve member is movable angularly about said axis to said positions.

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[0014] Preferably, said movable valve member is fixed to said chamber, so that movement of the movable valve member between its said positions is achieved by a user gripping said chamber causing angular movement of said chamber.

[0015] Preferably, the second valve is operable to simultaneously provide the first, third and fourth passages. [0016] Preferably, the second valve is operable to simultaneously provide the second, third and fourth passages.

[0017] Preferably, the second valve is operable to simultaneously provide the third and fourth passages.

[0018] Preferably, the second valve is operable to simultaneously provide the second and third passages.

[0019] Preferably, the second valve is operable to provide only the third passage.

[0020] Preferably, said second valve is operable to vary flow rate through the first passage between a maximum flow rate and zero flow rate

[0021] Preferably, the first, second, third and fourth passages are generally parallel to said axis.

[0022] Preferably, the burette further includes a base, with the body and movable valve member being attached with the movable valve member being movable angularly relative to the base about said axis.

[0023] Preferably, the second valve member is fixed to the body so that a user grips the body and moves the body relative to the base to move the second valve member relative to the base.

[0024] Preferably, the movable valve member is of a disc configuration.

[0025] Preferably, the burette further includes a seal located between the movable valve member and the base, with said seal having a plurality of passages aiding to provide the first, second and fourth passages.

[0026] Preferably, the seal and movable valve member provide a valve assembly, said base is a cap, and said cap engages said body so that the seal and movable valve member are located between the base and body.

[0027] Preferably, the first, second and fourth passages are generally parallel to said axis. BRIEF DESCRIPTION OF DRAWINGS

[0028] A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein:

[0029] Figure 1 is a schematic isometric view of a burette;

[0030] Figure 2 is a schematic isometric view of the end portion of the burette of Figure 1 :

[0031] Figure 3 is a schematic parts exploded isometric view of the end portion of Figure 2;

[0032] Figure 4 is a further parts exploded isometric view of the end portion of Figure 2;

^■ [0033] Figure 5 is a schematic illustration of portion of the burette of Figure 1;

[0034] Figure 6 is a schematic parts exploded isometric view of the portion of Figure 5;

[0035] Figure 7 is a schematic parts exploded isometric view of a modification of the portion of Figure 6;

[0036] Figures 8 to 12 are schematic illustrations of the portion of Figure 7 in various configurations; and

[0037] Figure 13 is a schematic sectioned side elevation of the end portion of the burette as shown in Figure 2.

DESCRIPTION OF EMBODIMENTS

[0038] In the accompanying drawings there is schematically depicted a medical burette 10 to provide for the delivery of intravenous liquids to a patient. The burette 10 would be connected via a tube 11 to a supply (bag) of liquid. A tube 12 would then extend from the burette 10 to the patient.

[0039] The burette 10 includes an elongated hollow (generally cylindrical) body 13 enclosing a chamber 14 that is to contain a liquid or liquids to be delivered intravenously. [0040] Secured to the upper end of the body 13 is an end assembly 15. Preferably, the end assembly 15 is a cap assembly. The lower end of the body 13 provides a chamber outlet 16 for the chamber 14.

[0041] The assembly 15 provides the burette 10 with a primary inlet 17 to which the tube 11 is connected. The assembly 15 also provides a port 18 via which a further liquid, such as a medication, may be introduced to the chamber 14. The port 18 may be an injection port.

[0042] Extending downwardly from the assembly 15 so as to extend into the chamber 14 is a tube 19.

[0043] Located in the chamber 14 is a float 20. The float 20 uses a guide member 59 and engagement in the outlet 16 to be guided thereby in its vertical movement. The float 20 is guided to engage the lower end of the tube 19 to close the tube 19, when the depth of liquid in the chamber 14 exceeds a predetermined level (depth). The guide member 59 holds the lower end of the tube 19 in position, with the float 20 having fingers 60 slidably engaging the lower end portion of the tube 19 so as to be guided thereby. If liquid in the chamber 14 is below a predetermined level, the float 20 allows liquid to exit the lower end of the tube 19. Operation of the float 20 and tube 19 can be as described in the above Australian patent 2006301931. That is, the tube 19 and float 20 operate as a float valve.

[0044] The assembly 15 includes a base that is preferably a cap 21 having a transverse wall 22 and a skirt 23. The skirt 23 incorporates a plurality of resiliently deformable fingers 24 having internal barbs 25 that snap engage over an annular ridge 51 adjacent the upper end of the body 13 to fix the cap assembly 15 to the body 13.

[0045] Located in the cap 21 is a valve assembly 26 including a seal 27 of a disk .

configuration, and a movable valve member 28. The movable valve member 28 includes an annular flange 29 fixed (by adhesive or welding) to the upper edge of the body 13 so as to be secured thereto. The movable valve member 28 is of a disk configuration and is moved relative to the seal 27 and the cap 21 via a user gripping the body 13 and causing angular movement of the body 13 about the upright longitudinal axis 30 of the burette 10 and the body 13 (and therefore chamber 14). [0046] The seal 27 sealingly connects the underside of the wall 22 with the movable valve member 28. However the seal 28 is also provided with a plurality of passages to provide for the flow of liquid to pass the seal 27.

[0047] The wall 22 is also provided with a radially extending passage (slot) 33 that communicates with the primary 17.

[0048] The port 18 communicates with a passage 32 in the wall 22.

[0049] The seal 27 is formed of resilient material such as synthetic or rubber or a plastics material, and acts as a seal between the cap 21 and the valve member 28. However the seal 27 is provided with a plurality of passages including a plurality of passages 31, and passages 34, 35 and 36.

[0050] The movable valve member 28 includes a wall 37 transverse of the axis 30 through which there extends a plurality of passages 38, and passages 40, 41 and 42. In addition there are passages (slots) 43 and 44 as well as an angular passage (slot) 45 communicating with the passage 44. The passage 45 extends angularly about the longitudinal axis 30 at a substantially constant radius. The passages 33, 43 and 44 extend radially relative to the axis 30.

[0051] The movable valve member 28 also includes the abovementioned annular ridge 51 over which the barbs engage.

[0052] The seal 27 also has a peripheral slot 52 that engages a projection 58 that extends inwardly relative to the wall 22 to retain the seal 27 stationary with respect to the cap 21.

[0053] In operation of the above described burette 10, the valve assembly 26 can be configured to provide a plurality of passages by moving the valve member 28 angularly about the axis 30 relative to the cap 21 and the seal 27.

[0054] The passages include a first passage 46 (Figure 12). The first passage 46 provides for communication between the primary inlet 17 and the tube 19 to deliver fluid to the interior 14, with the delivery being governed by operation of the float valve, that is the float 20. This passage 46 includes passages 33, 35, 41, 44 and 45. [0055] Flow rates through the passage 46 can also be varied. This is achieved by selecting the position at which the passage 35 communicates with the passage 45. If the communication is most remote from the passage 44, maximum resistance is provided. If however the passage 35 communicates close to the passage 44, then minimum resistance is provided thereby enhancing flow.

[0056] The second passage 47 provides for communication between the primary inlet 17 and the chamber 14 and includes passages 33, 35, 43 and 41 (Figure 1 1). The second passage can also be provided passages 33, 35 and 42 (Figure 9).

[0057] The third passage 48 provides a permanent communication between the port 18 and the chamber 14. The passage 48 includes passages 34 and 56 (Figure 8), passages 34 and 57 (Figure 9), passages 34 and 40 (Figure 10), passages 34 and 41 (Figure 11) and passages 34 and 38 (Figure 12).

[0058] The fourth passage 49 is a vent passage and uses one of the passages 50, one of the passages 31 and the passage 39 (Figure 12), one of the passages 50, the passage 55 and 39 (Figure 11), and one of the passages 50, the passage 36 and the passage 39 (Figure 10).

[0059] The valve assembly 26 can be configured by operation of a health professional to provide a variety of functions, with operation of the burette 10 being reasonably simple. The health professional merely grips the body 13 and moves it angularly relative to cap 21 about the longitudinal axis 30. This angular movement causes the valve member 28 to move relative to the valve member 27 and the cap 21.

[0060] In Figures 6 to 12 of the accompanying drawings, the cap 21, seal 27 and movable valve member 28 have been simplified to aid in the understanding of the operation of the valve 26. For example in Figure 6, the passages 31 are illustrated. However in Figure 7, the passages 31 are illustrated as a slot 31. The same applies to the passages 48 which are illustrated in Figure 7 as a slot 48. The same applies to the passages 50. Also in Figures 5 to 12, the cap 21, seal 27 and valve member 28 have a tag which aids in visualising their relative angular positions. The passages 46, 47, 48 and 49 extend substantially parallel to the axis 30. [0061] The functions provided by the burette including the following:

[0062] (1) "Autostart"

In this configuration the valve 26 provides the first, third and fourth passages 46, 48, 49 and is illustrated in Figure 12. In this configuration intravenous liquid is delivered via the primary inlet 17 and delivered to the chamber 14 via the tube 19 and by operation of the float 20. The vent passage 49 is open and the health professional may deliver medication to the port 18 for delivery to the chamber 1 ^* 4 via the passage 48. The passage 47 is not operative. The flow rate via passage 46 can also be varied to a "medium" flow rate.

[0063] (2) "Fill"

In this configuration the valve 26 provides the vent open as well as the second passage 47 and the third passage 48 together with the fourth passage 49. In this configuration medication delivered by the port 18 is flushed through the valve assembly 26 via the intravenous fluid delivered to the primary inlet 17. This configuration also provides for filling of the chamber 14. This configuration is illustrated in Figure 11. The passage 46 is not operative.

[0064] (3) "Empty"

In this configuration only the vent fourth passage 49 and the third passage 48 are opened and provides for emptying of the chamber 14 through the outlet 16. This configuration is illustrated in Figure 10. The passages 46 and 47 are not operative.

[0065] (4) "Tube"

In this configuration the third and fourth passages 48 and 49 are open. This configuration merely provides communication between the primary inlet 17 and the chamber 14, and bypasses operation of the float valve, that is cooperation of the float 20 and the lower end of the tube 19. This configuration is illustrated in Figure 9. The passages 46 and 47 are not operative. [0066] (5) "Stop"

In this configuration the passages 46, 47 and 49 are not operative. Only the third passage 48 is operative.

[0067] The positions of the movable valve member 28 to provide the above functions is identified by a plurality of recesses 53, in the annular ridge 51 , that snap engage with a ridge 54 of the cap 15. Each recess 53 corresponds to one of the above functions. When the ridge 41 is located therein, then the burette operates to provide the appropriate function.

[0068] The above described preferred embodiment provides a number of advantages including ease of operation, and providing the functions that are required of a health professional in operating devices for delivery of liquids intravenously, including burettes and clamps.