Flexible plastic hose and method for manufacturing same
Disclosed is a flexible plastic hose ( 1 ) comprising a tubular hose body ( 2 ) having web portions ( 7 ) and a helical reinforcing rib ( 8 ), and a cuff ( 3 a ) mounted to an extremity ( 16 ) of the hose body ( 2 ) comprising a molded end fitting ( 5 a ) bonded to the extremity ( 16 a ), and a stress relief element ( 4 ) with a first segment (S 1 ) having an internal screw-thread ( 15 ) complementary to the helical reinforcing rib ( 8 ). Disclosed is also a method for making same, and use of the hose ( 1 ) as a medical hose.
1. A flexible plastic hose comprising:
a hose body having a flexible tubular outer wall comprising web portions alternating with reinforcing rib portions of at least one helical reinforcing rib, the web portions having predetermined properties chosen for providing flexibility to the hose body and the at least one reinforcing rib having predetermined properties for providing crush resistance to the hose body; and
a cuff mounted to at least a first extremity of the hose body and comprising:
a stress relief element located at an entrance side of the cuff where the hose body enters the cuff, the stress relief element having a first segment with an internal screw-thread complementary to the helical reinforcing rib for and closely fitting around the hose body without being bonded to the first extremity of the hose body, the stress relief element being for reducing stress exerted on the web portions at the first extremity during use of the hose, wherein the stress relief element is screwed onto the first extremity of the hose body such that a portion of the first extremity of the hose body extends beyond the stress relief element; and
a moulded end fitting having a bore for connecting the hose to another device, the end fitting being integrally moulded on the first extremity of the hose body and over part of the stress relief element and being bonded to said part of the stress relief element and said portion of the first extremity of the hose body.
2. The flexible plastic hose according to claim 1 , wherein the stress relief element further comprises a second, substantially cylindrical segment without the internal screw-thread at the entrance side of the cuff, having an inner diameter provided for closely fitting around the reinforcing rib in axial direction but allowing flexibility of the hose body in its longitudinal direction.
3. The flexible plastic hose according to claim 1 , wherein the stress relief element further comprises a first and a second substantially cylindrical outer surface having a first resp. second outer diameter, the first cylindrical outer surface being said part of the stress relief element over which the moulded end fitting is mounted and to which the moulded end fitting is bonded.
4. The flexible plastic hose according to claim 3 , wherein the first cylindrical outer surface further comprises protrusions and/or recessions for also providing a mechanical lock between the moulded end fitting and the stress relief element.
5. The flexible plastic hose according to claim 1 , wherein the internal screw thread of the stress relief element extends over at least half a winding of the helical reinforcing rib.
6. The flexible plastic hose according to claim 1 , wherein the pitch of the rib or ribs is at least 3.0 mm.
7. The flexible plastic hose according to claim 1 , wherein the wall thickness of the web portions is 0.10-0.25 mm.
8. The flexible plastic hose according to claim 1 , wherein the web portions are made of a material chosen from the group comprising: polyolefin, metallocene PE, polyvinylchloride (PVC), flexible PVC, and any other material approved according to ISO 10993 for use in medical applications.
9. The flexible plastic hose according to claim 1 , wherein the rib comprises at least one material selected from the group of: polypropylene, polyethylene, and any other material approved according to ISO 10993 for use in medical applications.
10. The flexible plastic hose according to claim 1 , wherein the end fitting comprises a material selected from the group of: polypropylene, polyethylene, polyester and any other material approved according to ISO 10993 for use in medical applications.
11. The flexible plastic hose according to claim 1 , wherein at least one electrical wire/cable is integrated into the outer wall of the hose body.
12. The flexible plastic hose according to claim 11 , wherein the at least one electrical wire/cable is connected to an electrical interface integrated in the end fitting of the cuff.
13. A method of manufacturing a flexible plastic hose, comprising the steps of:
a) providing a hose body having a flexible tubular outer wall comprising web portions alternating with reinforcing rib portions of at least one helical reinforcing rib, the web portions having predetermined properties chosen for providing flexibility to the hose body and the at least one reinforcing rib having predetermined properties for providing crush resistance to the hose body;
b) providing a stress relief element having a first segment with an internal screw thread complementary to the helical reinforcing rib provided for closely fitting around the hose body;
c) screwing the stress relief element on a first extremity of the hose body, such that the at least one helical reinforcing rib is engaged in the internal thread of the stress relief element and the stress relief element closely fits around the first extremity without being bonded thereto, and in such a way that the extremity of the hose body extends beyond the stress relief element;
d) integrally moulding or spin welding an end fitting having a bore onto the first extremity of the hose body and over part of the stress relief element, such that the end fitting is bonded to the first extremity and the stress relief element.
14. The flexible plastic hose according to claim 1 , wherein the hose is manufactured in predetermined plastic materials suitable for medical purposes.
15. The flexible plastic hose according to claim 14 , wherein at least one electrical wire is integrated into the outer wall of the hose body, the electrical wire preferably being located inside and isolated by the reinforcing ribs, and being provided for a purpose or use selected from (i) warming up a fluid inside the hose body, (ii) as a temperature sensor, (iii) as a humidity sensor, (iv) as a sensor for oxygen, carbon dioxide presence, and (v) for any other type of sensor.
16. The flexible plastic hose according to claim 1 , wherein the internal screw thread of the stress relief element extends over at least one winding of the helical reinforcing rib.
17. The flexible plastic hose according to claim 1 , wherein the internal screw thread of the stress relief element extends over at least two windings of the helical reinforcing rib.
18. The flexible plastic hose according to claim 1 , wherein the pitch of the rib or ribs is at least 5.0 mm.
19. The flexible plastic hose according to claim 1 , wherein the wall thickness of the web portions is 0.16-0.22 mm.
20. The flexible plastic hose according to claim 9 , wherein the rib is surrounded by a coating comprising the same material as is used in the web, or a material compatible therewith.
21. The flexible plastic hose according to claim 1 , wherein at least one electrical wire/cable is integrated into the outer wall of the hose body, the electrical wire/cable being integrated in the reinforcing ribs or in the web.