SPIKE CONNECTOR FOR AN INFUSION SET

Abstract: An improved needle device for infusion of the type including a liquid delivering passage and an air introducing passage extending in parallel with each other is disclosed. The needle device comprises a tubular needle (1), a bottom portion (6) into which the rear part of the tubular needle is immovably fitted, a flange portion (9) made integral with the bottom portion, a cover member (4) airtightly secured to the flange portion and a valve disc (8) received beneath a circular projection on the flange-shaped part of the cover member. As air enters through an air inlet port (10) on the flange portion, the valve disc is raised up so that air is introduced into the interior of a parenteral liquid container via a cutout on the circular projection, a clearance between the bottom portion and the cover member and an annular clearance between the tapered foremost end of the cover member and the tubular needle. When liquid in the container flows out through the air inlet port, the valve disc comes in the inside wall surface of the flange portion under the effect of dead weight of the liquid itself to close the air inlet port with the valve disc.

Description: BACKGROUND OF THE INVENTION Technical Field of the Invention The present invention relates a needle device for infusion of the type including a liquid delivering passage and an air introducing passage extending in parallel with each other. Such a device is disclosed in GB-A-2 105 695 and in EP-A-0 001 144. Description of the Prior Art In general, a parenteral liquid infusion set is constructed such that a needle device is provided at one end so as to allow a tubular needle to be pierced into the interior of a container in which parenteral liquid is contained and a vein needle is provided at the other end thereof to be pierced to a vein of a patient. In addition, the infusion set includes a drip chamber and a flexible tube extending between the needle device and the vein needle. The conventional needle device required for the infusion set is classified into two types, i.e., one of them being such that it includes only a liquid delivering passage but an air introducing passage is provided separately and the other one being such that it includes a liquid delivering passage and an air introducing passage extending in parallel with each other. A few examples of the needle device of the last-mentioned type are disclosed in official gazettes of Japanese Published Utility Model NO. 36400/1976, Japanese Laid-Open Utility Model NO. 30232/1985 and Japanese Laid-Open Utility Model NO. 30233/1985. Specifically, the needle device as disclosed in Japanese Published Utility Model NO. 36400/1976 is such that a needle tube is divided into two passages, one of them serving as a liquid delivering passage and the other one serving as an air introducing passage. The needle device as disclosed in Japanese Laid-Open Utility Model NO. 30232/1985 is such that a needle tube is formed with a longitudinally extending groove on the side wall thereof so as to allow the groove to serve as an air introducing passage. Further, the needle device as disclosed in Japanese Laid-Open Utility Model NO. 30233/1985 is such that a needle tube is contoured in a double walled structure so that the inner passage serves as a liquid delivering passage and the outer passage serves as an air introducing passage. Normally, the air introducing passage is fitted with a filter for preventing dust and bacteria in the air from being introduced into the interior of a container. Lately, the filter has been molded of hydrophobic material such as polytetrafluoroethylene resin or the like resin so as to prevent liquid in the container from flowing back to the outside. A needle device of the type including a liquid delivering passage and an air introducing passage extending in parallel with each other can simply be used but it has a problem that it is bulky and complicated in structure, resulting in an increased production cost. With the needle device including an air introducing passage which is fitted with a filter made of hydrophobic material, if liquid contains a surface active agent, there arises a problem that the liquid is liable to gradually permeate through the filter. Another problem is that once the filtered is filled with liquid, air permeates therethrough with much difficulties. SUMMARY OF THE INVENTION The present invention has been made with the foregoing background in mind and its object resides in providing a needle device for infusion of the type including a liquid delivering passage and an air introducing passage extending in parallel with each other wherein the device is simple in structure, has smaller dimensions and can easily be produced at an inexpensive cost. Other object of the present invention is to provide a needle device for infusion of the type including a liquid delivering passage and an air introducing passage extending in parallel with each other wherein the device assures that liquid does not undesirably flow or leak to the outside. To accomplish the above objects, the present invention provides a needle device according to claim 1. Still, there is no barrier to the air flow even the cutout is one, but it may be provided for more than two. As air enters through the air inlet port, the valve disc is raised up so that air is introduced into the interior of a parenteral liquid container via the cutout on the circular projection, a groove on the inside wall surface of the flange portion, a clearance between the cover member and the rear portion of the tubular needle and an annular clearance between the foremost tapered end of the cover member and the tubular needle. When liquid in the container flows out via the air inlet port, the valve disc is brought in close contact with the inside wall surface of the flange portion under the effect of force derived from dead weight of the liquid itself to close the air inlet port with the valve disc while preventing the liquid from flowing out through the air inlet port. It is preferable that the flange portion is airtightly secured to the cover member by welding or by using an adhesive. Other objects, features and advantages of the present invention will be readily apparent from reading of the following description which has been made with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustrated in the following drawings in which: Fig. 1 is a sectional view of a needle device for infusion in accordance with an embodiment of the present invention, and Fig. 2 is a cross-sectional view of the needle device taken in line A - A' in Fig. 1. DESCRIPTION OF THE PREFERRED EMBODIMENT Now, the present invention will be described in detail hereinafter with reference to the accompanying drawings which illustrate a preferred embodiment thereof. Fig. 1 is a sectional view of a needle device in accordance with an embodiment thereof. As will be apparent from the drawing, the needle device of the present invention includes a tubular needle 1, a needle bottom portion 6, a cover portion 4 and a valve disc 8. The tubular needle 1 is sharpened so as to allow its foremost portion to be pierced into a rubber stopper. In the illustrated embodiment, the foremost portion of the tubular needle 1 is formed with an opening at the foremost end thereof like an injection needle. Alternatively, the foremost end of the tubular needle 1 may be kept closed but the needle 1 may be formed with an opening on the side wall thereof. This arrangement prevents a part of the rubber stopper from being cut off by a piercing operation of the needle 1. The rear end part of the tubular needle 1 is firmly held by the bottom portion 6 using an adhesive. The bottom portion 6 is made integral with a flange 9 at a substantially middle part therof and an air inlet port 10 is formed on the flange 9. An air permeable sheet 11 is adhesively attached to the outer surface of the flange 9 to cover the air inlet port 10 therewith, and the valve disc 8 is placed inside of the air inlet port 10. Any material is employable for the air permeable sheet 11, if it is proven that it prevents dust and bacteria in the air from passing through the air permeable sheet 11. Generally, it is preferable to use paper or nonwoven fabric for the air permeable sheet 11 from the viewpoint of strength, productivity and cost. The air permeable sheet 11 can be attached round the circular edge of the air inlet port 10 by welding the peripheral edge of the air permeable sheet 11 or using an adhesive. The valve disc 8 is molded of flexible material such as rubber, soft synthetic resin or the like and it is particularly preferable to employ silicone rubber as material for the valve disc 8. The valve disc 8 is preferably designed in the form of a circular disc but a contour of the valve disc 8 should not be limited only to this. Alternatively, other suitable contour may be employable. Usually, a thickness of the valve disc is determined in the range of 0.2 to 0.8 mm. The cover member 4 is designed to surround the rear end part of the tubular needle 1 and the front side of the flange 9 and it is airtightly secured round the periphery of the flange 9. As is apparent from Fig. 1, the fore part of the cover member 4 is tapered to facilitate piercing of the foremost end of the cover member 4 into a container, and an annular fine clearance is formed between the tubular needle 1 and the inner wall of the tapered part of the cover member 4 so as to allow air to flow therethrough. In addition, an annular clearance is provided between the bottom portion 6 of the tubular needle 1 and the cover member 4 so that air is introduced into the container via the air inlet port 10 and the foregoing annular clearances. As is best seen in Fig. 2 which is a sectional view of the needle device taken in line A - A' in Fig. 1, the cover member 4 is formed with a circular projection 7 in which a part of the valve disc 8 is received. The circular projection 7 is cut out at the left-hand part as seen in Fig. 2 so that the annular clearance between the cover member 4 and the bottom portion 6 is communicated with the cutout of the circular projection 7 via a groove on the inside wall of the cover member 4. Normally, air which has entered through the inlet port 10 lifts up the valve disc 8 to create a clearance between the valve disc 8 and the inside wall of the flange 9, whereby it flows into the interior of the needle device via the thus created clearance. If it happens that liquid in the container flows down against the air flow, it depresses the valve disc 8 on the inside wall surface of the flange 9 under the effect of gravity force of the liquid itself to close the inlet port 10 with the valve disc 8. Consequently, the valve disc 8 prevents the liquid from flowing out through the inlet port 10 via the cutout of the circular projection 7. If this cutout is excessively narrow, air flowing is obstructed. On the contrary, if it is excessively wide, the valve disc 8 is held unstably. Thus, a size of the cutout should preferably be determined in the range of 5 to 180 degrees in terms of an angle as seen from the center of the circular projection 7. Still, there is no barrier to the air flow even the cutout is one, but it may be provided more than two. In the case where the number of cutout is plural, the total angle should be determined in said range. As mentioned above, the cover member 4 is airtightly secured to the flange 9. It is preferable that this airtight securing is accomplished by welding or by using an adhesive. Particularly, it is most preferable that airtight securing is accomplished by employing a supersonic welding process. The needle device of the present invention is practically used in such a manner that a tube of a infusion set or a drip chamber is connected to the rear end of the needle device. When the needle device is put in practical use, the tubular needle 1 and the tapered fore end of the cover member 4 are pierced into the interior of a parenteral liquid container through a rubber stopper. Liquid in the container flows out from the rear end of the bottom portion 6 through the interior of the tubular needle 1, while air is introduced into the interior of the container via the air permeable sheet 11, the air inlet port 10, the clearance between the valve disc 8 and the inside wall of the flange 9 and the annular clearance 2 between the tubular needle 1 and the foremost end of the cover member 4. Usually, the tubular needle 1 is made of metallic material, e.g., stainless steel. Alternatively, it may be made of hard synthetic resin. It is preferable that the bottom portion 6 and the cover member 4 are molded of synthetic resin by employing an injection molding process. Since the both members are simple in configuration, there is no need of using a split mold assembly, and a number of members can simultaneously be molded using a single mold. Polypropylene, ABS resin, polyethylene and polycarbonate can be noted as a typical synthetic resin for molding the bottom portion 6 and the cover member 4. Since the needle device of the present invention is simple in structure and can be produced on a mass production line, it can be designed in smaller dimensions and produced at an inexpensive cost. Thus, it can preferable be used as a disposable type medical instrument. In addition, since it is equipped with a reverse flow preventive valve, there is no danger that liquid in a parenteral liquid container leaks out from the air inlet port. Consequently, it can safely be used for any kind of parenteral liquid. While the present invention has been described above with respect to a single preferred embodiment thereof, it should of course be understood that it should not be limited only to this but various changes or modifications may be made without departure from the scope of the present invention as defined by the appended claims.

Claims: A needle device for infusion of the type including a liquid delivering passage and an air introducing passage, comprising: a tubular needle (1) of which the foremost end is sharpened, said tubular needle (1) serving as said liquid delivering passage, a bottom portion (6) into which the rear part (5) of the tubular needle (1) is firmly fitted, a flange portion (9) made integral with said bottom portion (6), said flange portion (9) being formed with an air inlet port (10) which is covered with an air permeable sheet (11), a cover member (4) in which the rear part (5) of the tubular needle (1) and the bottom portion (6) are received with a clearance held therebetween, respectively, said cover member (4) being airtightly secured to said flange portion (9), the fore part of the cover member (4) being tapered with said needle protruding therethrough, and while defining an annular clearance between the inner wall of the cover member and the tubular needle (1), said annular clearance serving as said air introducing passage, and a valve disc (8) of elastomeric material is placed on the air inlet part (10) of the flange portion (9), said valve disc (8) being received between a circular projection (7) on the flange-shaped part of the cover member (4), and the flange (9) a part of said circular projection (7) being cut out to define an air passage, such that air can enter through said air inlet port (10), whereby the valve disc (8) is raised up so that air is introduced into the interior of a parenteral liquid container, and when liquid in said container flows down into the air passage, the valve disc (8) is brought in close contact with the inside wall surface of the flange portion (1) due to the weight of said liquid itself so as to prevent leakage of liquid through the air inlet port. The needle device as claimed in claim 1, wherein (more than two) cutouts in the circular projection (7) are provided. The needle device as claimed in claim 1, wherein the flange portion is airtightly secured to the cover member by welding or by using an adhesive. The needle device as claimed in any of the preceeding claims, when said cover member (4) is airtightly secured around the periphery of the flange (9).

Inventors: IWATA, MINORU, NOJI, YUKIO, YAMASHITA, HIDEYUKI
Applicants: JAPAN MEDICAL SUPPLY CO., LTD.
Application year: 1990
Main classification: A61M5
IPC codes: A61M5