PERISTALTIC PUMP TUBE

Abstract

A tube for a peristaltic pump comprises an elastically deformable tubular body (2) made from a PVC composition containing: 100 phr of a PVC resin having a K value, measured according to standard ISO 1628-2, of not less than 85, from 40 to 100 phr of DEHA plasticizer, from 0.05 to 1.0 phr of lubricant, from 0.3 to 15.0 phr of stabilizer and co-stabilizer. The deformable tube, which is usefully employed for liquid transport in a dialysis apparatus, enables a high level of fluid transport efficiency to be maintained, even after many hours of peristaltic pump operation.

Claims

1-20. (canceled)

21: An apparatus for extracorporeal blood treatment comprising: a rotary peristaltic pump including a rotor having at least one squeezing roller, and a stator; a tube for placement between the rotor and the stator, the tube including an elastically deformable tubular body configured to be repeatedly squeezed by the at least one squeezing roller, the tubular body made from a material including a blend of at least: a vinyl chloride resin having a K value of not less than 85 measured according to standard ISO 1628-2, and a plasticizer including an ester of adipic acid; and a fluid transport line in fluid communication with the tube.

22: The apparatus of claim 21, wherein the tube is insertedly attached to the fluid transport line.

23: The apparatus of claim 21, wherein the fluid transport line is positioned and arranged (i) for an extracorporeal blood transport, (ii) as an infusion line for a medical fluid, (iii) as a dialysis fluid supply line to a dialyzer, or (iv) as a drainage line.

24: The apparatus of claim 21, wherein the rotor induces a negative pressure within an inlet of the tube of less than −200 mmHg.

25: The apparatus of claim 21, wherein the material is at least one of (i) not above 100 phr of the plasticizer, wherein phr means parts by weight per hundred parts by weight of resin, (ii) above 40 phr of the plasticizer, (iii) between 40 and 100 phr of the plasticizer, or (iv) between 50 and 80 phr of the plasticizer.

26: The apparatus of claim 21, wherein the material includes (i) 100 phr of the vinyl chloride resin, (ii) from 40 to 100 phr of the plasticizer, (iii) from 0.05 to 1.0 phr of one or more lubricants, and (iv) from 0.3 to 15.0 phr of one or more stabilizers and co-stabilizers.

27: The apparatus of claim 21, wherein the ester of adipic acid is an alkyl ester.

28: The apparatus of claim 27, wherein the alkyl ester is DEHA.

29: An apparatus for extracorporeal blood treatment comprising: a rotary peristaltic pump including a rotor having at least one squeezing roller, and a stator; a tube for placement between the rotor and the stator, the tube including an elastically deformable tubular body configured to be repeatedly squeezed by the at least one squeezing roller, the tubular body made from a material including a vinyl chloride resin having a K value of not less than 85 measured according to standard ISO 1628-2, and wherein the tubular body is made entirely of a single layer of the material; and a fluid transport line in fluid communication with the tube.

30: The apparatus of claim 29, wherein the tube is insertedly attached to the fluid transport line.

31: The apparatus of claim 29, wherein the fluid transport line is positioned and arranged (i) for an extracorporeal blood transport, (ii) as an infusion line for a medical fluid, (iii) as a dialysis fluid supply line to a dialyzer, or (iv) as a drainage line.

32: The apparatus of claim 29, wherein the rotor induces a negative pressure within an inlet of the tube of less than −200 mmHg.

33: The apparatus of claim 29, wherein the material includes (i) 100 phr of the vinyl chloride resin, wherein phr means parts by weight per hundred parts by weight of resin, (ii) from 40 to 100 phr of the plasticizer, (iii) from 0.05 to 1.0 phr of one or more lubricants, and (iv) from 0.3 to 15.0 phr of one or more stabilizers and co-stabilizers.

34: An apparatus for extracorporeal blood treatment comprising: a rotary peristaltic pump including a rotor having at least one squeezing roller, and a stator; a tube for placement between the rotor and the stator, the tube including an elastically deformable tubular body configured to be repeatedly squeezed by the at least one squeezing roller, the tubular body made from a material including a vinyl chloride resin having a K value configured to produce not more than a thirty percent drop in flowrate over at least seventy hours of operation; and a fluid transport line in fluid communication with the tube.

35: The apparatus of claim 34, wherein the flowrate as commanded is constant over the at least seventy hours of operation.

36: The apparatus of claim 34, wherein the K value is not less than 85 measured according to standard ISO 1628-2.

37: The apparatus of claim 34, wherein the K value is no more than 105 measured according to standard ISO 1628-2.

38: The apparatus of claim 34, wherein the material further incudes a plasticizer including an ester of adipic acid.

39: The apparatus of claim 34, wherein the material is at least one of (i) not above 100 phr of the plasticizer, wherein phr means parts by weight per hundred parts by weight of resin, (ii) above 40 phr of the plasticizer, (iii) between 40 and 100 phr of the plasticizer, or (iv) between 50 and 80 phr of the plasticizer.

40: An apparatus for extracorporeal blood treatment comprising: a rotary peristaltic pump including a rotor having at least one squeezing roller, and a stator; a tube for placement between the rotor and the stator, the tube including an elastically deformable tubular body configured to be repeatedly squeezed by the at least one squeezing roller, wherein the tubular body is made entirely of a single layer of a material including: 100 phr of a vinyl chloride resin, wherein phr means parts by weight per hundred parts by weight of resin, from 50 to 80 phr of a plasticizer comprising DEHA, from 0.05 to 1.0 phr of one or more lubricants, and from 0.2 to 10.0 phr of one or more stabilizers based on calcium and zinc and one or more co-stabilizers comprising epoxy soya oil; and a fluid transport line in fluid communication with the tube.

41: The apparatus of claim 40, wherein the tube includes: an external cylindrical surface, an internal cylindrical surface, a thickness of about 0.8 millimeter, and an internal diameter of about 3.2 millimeters.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 shows a sectioned tract of a tube realised in accordance with the present invention.

[0018] FIG. 2 is a schematic view of a peristaltic pump comprising the tube of FIG. 1.

[0019] FIG. 3 illustrates a dialysis set comprising the tube of FIG. 1.

[0020] FIG. 4 is a diagram comparing the percentage drop in flow rate in a peristaltic pump over a period of time, for a deformable tube of the invention and for a deformable tube of another type.

DETAILED DESCRIPTION

[0021] With reference to FIG. 1, 1 denotes in its entirety a tube for a peristaltic pump, comprising an elongate tubular body 2 which is elastically deformable by squeezing, and which is flexible. The tubular body 2 has a cylindrical, smooth and continuous surface, and an internal surface which is also cylindrical, smooth and continuous, has a thickness of about 0.8 millimetre and an internal diameter of about 3.2 millimetres. The tubular body 2 is made from a material containing at least a vinyl chloride resin and an least a plasticizer. The tubular body 2 is made whole, in a single layer of the said material.

[0022] The PVC resin used has a K value, measured according to ISO 1628-2 standards, of not less than 85. More specifically, the resin has a K value, measured according to ISO 1628-2, of not less than 95. In laboratory testing, the results of which will be described herein below, a PVC resin was used that had a rated K value of 100. The use of polymerized vinyl chloride with K above 95 is known, for example from DE 4317741, for producing PVC formulations used in the thermoplastic manufacturing of soft elasticized products by extrusion, pressing, calendering or sintering.

[0023] The material of the tubular body 2 contains a quantity of plasticizer which is not above 100 phr, where phr means parts in weight per hundred parts of resin. The plasticizer content is also above 40 phr. In greater detail, the content in weight of plasticizer in the tubular body 2 is comprised between 50 and 80 phr. In a specific embodiment which has been subjected to laboratory testing, the material of the tubular body contains about 75.5 phr of plasticizer. In the embodiment the plasticizer used is a monomer.

[0024] The plasticizer comprises, in particular, a derivative of adipic acid. More specifically, the derivative can be an alkyl ester of adipic acid, such as for example di-2-ethyl-hexyl-adipate, commonly known as DOA or DEHA. The use of DEHA as a plasticizer for PVC compositions in the manufacturing of bio-compatible articles is known, for example from patent publication U.S. Pat. No. 5,955,519.

[0025] A formulation of the material used for realising the tubular body 2 is the following: [0026] 100 phr of PVC resin; [0027] from 40 to 100 phr of plasticizer; [0028] from 0.05 to 1.0 phr of one or more lubricants; [0029] from 0.1 to 5.0 phr of one or more stablizers; [0030] from 0.2 to 10.0 phr of one or more co-stabilizers.

[0031] Any type of lubricant suitable for PVC mixtures can be used.

[0032] Among the usable stabilizers are Ca/Zn stabilizers, based on calcium and zinc.

[0033] A usable co-stabilizer is, for example, epoxy soya oil (ESO), although other types of known co-stabilizers suitable for PVC can be used.

[0034] The deformable tube, especially in the case of medical use, can be sterilized using any known sterilization process, such as for example using penetrating beta/gamma rays or ethylene oxide. The above-illustrated PVC composition exhibits good resistance to penetrating rays.

[0035] FIG. 2 schematically shows a peristaltic pump 3 for transport of a fluid, using a deformable tube 1 such as the one described above. The peristaltic pump 3, which in the embodiment is rotary, comprises a rotor 4 provided with a plurality of squeezing rollers 5, a stator 6 external of the rotor, and a deformable tube arranged between the rotor 5 and the stator 6. The deformable tube is inserted in a fluid transport line 7 which can be, for example, a line for extracorporeal blood transport, or an infusion line for a medical fluid, or a dialysis fluid supply line to a dialyzer filter, or an out-flowing discharge fluid drainage line from a blood treatment unit, and so on.

[0036] FIG. 3 shows, schematically, a set for fluid transport in an extracorporeal blood treatment; more specifically it shows a set for extracorporeal blood transport for a dialysis treatment. The set comprises an arterial line 8, provided with a pump segment 9 realized by the tube of the present invention, and a venous line 10, each provided with one end, respectively 81 and 101, for connection to the blood circulation system of a patient, and another end, respectively 82 and 102, for connection to a blood treatment unit (of known type and not illustrated).

[0037] The tube of the invention is for coupling a peristaltic pump of the type which is operatively associated, in particular, to apparatus for extracorporeal blood treatment, such as for example apparatus predisposed to perform one or more of the following treatments: hemodialysis, hemofiltration, therapeutic plasma exchange, hemodiafiltration, pure ultrafiltration.

[0038] These apparatus can be of a type suitable for intensive treatment of kidney failure, or of a type suitable for periodic treatments.

[0039] The tube of the invention is further couplable with peristaltic pumps suitable for other medical uses such as, for example, apparatus for infusion of a medical fluid into a patient where there is the presence of at least one peristaltic pump.

Example

[0040] A deformable tube for a peristaltic pump was manufactured using the following PVC formulation: [0041] 100 phr of PVC resin with K of about 100, commercially known as Vinnolit® S 4099; [0042] 75.5 phr of DEHA plasticizer; [0043] 5.0 phr of ESO co-stabilizer; [0044] 1.2 phr Ca/Zn stabilizer; [0045] 0.2 phr of lubricant.

[0046] The tube was made by extrusion of a blend of the above ingredients. The blend was heated to a temperature of between 120 and 150° C. to enable good blending of the various components, after which the resulting dry blend was used for extrusion of the tube. Extrusion temperature for the deformable tube was about 160-180° C. Tube dimensions are those of the tube 1 of FIG. 1. The extruded tube was then sterilized using ethylene oxide and applied together with a rotary peristaltic pump of a dialysis machine for various operational hours.

[0047] The diagram of FIG. 4 shows, on the horizontal axis, the operational time expressed in hours, and on the vertical axis the drop in the test fluid flow rate through the peristaltic pump, expressed in percentage terms with respect to the initial flow rate with the tube when not in a worn state.

[0048] The diagram of FIG. 4 includes an indication of the drop in flow rate over a time period, with the peristaltic pump rotor speed kept at a constant rate, of the deformable tube made according to the above description (PVC with K=100). In a second line the drop in flow rate is indicated at the same rotor speed and the same pressure P.sub.in at the pump inlet (P.sub.in=−200 mmHg), using a tube of the same dimensions as the above, but made using a PVC composition in which the PVC resin is about K=80.

[0049] It has been demonstrated, then, that thanks to the tube made according to the present invention, the drop in flow rate caused by tube wear is considerable reduced.

[0050] More specifically, the above improvement is particularly evident in use with peristaltic pumps with deformable tubes, where, during use, the negative pressure at pump inlet P.sub.in is less than about −20 mmHg.