FR2661093A1 - Medical syringe made of plastic material, intended to be used only once, and neutralised by means of a chemical reaction which divides the shaft from the plunger - Google Patents

Abstract

The shaft consists of a tube made of plastic material with a very low melting point, its lower part is narrowed following a step (2) at the base of which a channel (3) is hollowed out, in which channel a ring of chemical substance (4) is fitted. During the injection push, a layer of chemical substance (7) spread over a step (6) hollowed out in a piece of tubular cross-section (1) held in the lumen of the syringe, and resting on the head of the plunger, comes into contact with the ring of chemical substance (4), resulting in a reaction which produces heat and divides the shaft from the plunger by means of melting of the plastic material at the base of the channel (3) to which there corresponds, on the inside of the shaft, a channel (5).

Description

 Medical syringe in disposable plastic nin reusable neutralization resulting from a chemical reaction.

 Actually, the abusive reuse but to which nothing is opposed on the technical level of serum intended for a single use is at the base of numerous contaminations favoring the transmission of seric diseases such as hepatitis B and AIDS (mainly in addicts). The latter disease, due to the current non-existence of a vaccine or effective treatment, gives the problem a renewed acuity and gravity.

 The syringe according to the invention is designed in such a way that only a round trip of the piston is possible.

The very beginning of the injection push, whether for the actual injection or for the expulsion of air or the adjustment of the quantity of liquid to be kept in the syringe, leads to a rupture of the plunger handle, both of which parties can however ensure the continuation of the injection, one being pushed by the other. But any new traction test on the handle is ineffective because the handle, amputated from its distal part, remains between the fingers of the manipulator. Note that the syringe is described here in a vertical position, needle pointing down, the upper body of the syringe is closed. The needle is welded to the syringe.

 The piston handle is a fairly large plastic tube, the lower part of which, overhanging the head by 1 or 2 cm, is narrowed. The passage from the upper part, wider, to the lower part, is done by a step in the hollow of which is hollowed a deep circumferential gutter to which responds, inside the handle, another gutter. This results in a considerable thinning of the puroi. A ring (toroid) of chemical A occupies the external gutter.

Surrounding the entire lower part and a few millimeters from the upper part of the handle, is a piece in the form of a tube section (FST 1) resting on the piston head and composed of two equal parts repaired longitudinally with a slight interlocking. This piece is in a tight position in the light of the serinque. However, it
is joined, but without any pressure, on the handle, according to a studied contiguity:
Thus, from bottom to top, over the greatest height of the narrowed lower part of the handle, and this up to a distance of a few millimeters from the crown of chemical substance A, this piece FST 1 is adjacent to the handle. Then it sees its internal diameter suddenly enlarge by a step. This enlarged diameter is that of the rest of the part to which it allows to pass at a distance from the very upper part of the narrowed part of the handle then to thread, on a few millimeters, the wide part of the handle on which
it fits without pressure.

 A chemical substance B is spread on the upper edge, looking up at the step appearing inside part FST 1.

The characteristic of chemical substances A and B is to react with each other by producing a sufficient quantity of heat intended to melt the plastic material at the level of the very thinned part of the wall of the handle. This amount of heat will be very minimal if we take within
make the plunger handle from a plastic material with the lowest possible melting point. The small space between the two steps and containing the two chemicals, A at the top and B at the bottom, is hermetically sealed. One can deposit there a substance (powder for example) able to protect the chemical substances A and B against humidity and, thus, to preserve very long their properties.

Contact between substances A and B occurs from the start of the injection. The manipulation takes place as follows:
- During the suction pulling on the piston handle, the FST 1 part is pushed upwards with a little effort because it is tightened in the syringe) by the piston head.

- At the start of the push on the handle the piston head descends, alone, over a distance of a few millimeters then the step of the handle is in contact with the step
of the FST 1 piece facing it. Note that in order for
the space between the two steps does not make room for
compression and thus compromises their rapprochement, the two
half-pieces (FST 1) are traversed longitudinally in their
middle with a channel starting, below, at the level of the section
placed on the piston head and ending at the top in the middle of
the horizontal side of the step. Thus, the class space will be set
in communication with the outside from the start of the push
on the piston, and only then, because the piston head, in
descending, releases the lower orifice of the channel.

The FST 1 part and the piston head then descend
Thanks to the contact between the two steps the
crown of chemical A comes into contact with the layer
of chemical substance B, which produces heat and melts
the very thin layer of plastic at the bottom of the gutter containing the crown of chemical A.

- Although the piston handle is thus cut in
two parts, the descent of the piston can continue in
normal mechanical conditions because the top most
wide of the handle is sheathed, therefore stabilized, in the part
thinned upper part FST 1.

- The injection completed or not, no aspiration of
liquid is no longer possible because, if the manipulator pulls on the
sleeve, the upper part of it remains between the
fingers.

In another embodiment according to a variant
the piston handle and the FST 2 part include several
opposite markets with as many layers of substances
chemicals. The neck is also weakened by a pre-cut
vertical page with circumferential layout exceeding by
a few millimeters above and below the gutters dug
in the wall and future sites of thermal cutting.

In an embodiment according to another variant
chemicals and nature plastic
constituting the handle are studied to allow, during the
"chemical contact", a segmentation of the handle based on a
specific chemical action solubilization, extreme embrittlement,
crystallization etc ...) and not (or not exclusively) thermal.

In another embodiment the handle of the piston is composed of two distinct parts joined together by gluing a separate strip of paper sufficient tensile strength, but specially studied in the sense of great vulnerability to the future chemical reaction. The upper part of the handle is slightly larger in diameter. On the paper exactly at the level of the line separating the two parts of the handle, runs a thin line of chemical substance D. Piece FST 3, which does not include any upper shrinkage here, lines the lower part of the handle up to a distance of a few millimeters from the line of chemical substance D. On the upper and internal edge of the part FST 3 is applied a layer of chemical substance E intended to react, from the start of the injection push, with chemical substance D paper which is then destroyed sectioned)
It should be noted that, the upper part of the piston handle, being wider, does not allow the FST 3 part to encason it. Chemicals D and E will therefore not "create" but will remain in contact.

 In another embodiment a special photosensitive chemical is distributed at the base of the plunger handle, flush with the plunger head, in a deep circumferential gutter. It is masked by a piece in the form of a section of tube FST 4 clamped in the lumen of the syringe and resting on the head of the piston. Piston and FST 4 part are black. At the start of the injection push, the FST 4 piece remains high and lets in the light which acts on the photosensitive substance, the reaction of which produces sufficient heat to melt the plastic (at a very low melting point) very thinned at the bottom of the circumferential gutter. Thus the piston head is separated from the handle. It is obvious that the assembly of this model must be done in a dark room.

 In another similar embodiment, the chemical reacts on contact with air which slides between an FST 5 part (perforated longitudinally) and the piston head when the injection push begins.

the chemical used is between
two paper renderings slightly glued together but
strongly adhering, one (the upper one) to part FST 5, and
the other ('lower) to the piston head. The two renderings are
therefore separated from the start of the injection thrust. During
assembly, the double washer is simply inserted between
the piston head and the FST part 5.

In another form of realization the substanc
chemical is an appropriate mixture of two reacting substances
thermally, one in light, the other in contact with air.

These two substances also being between two
paper washers.

It should be noted that in all forms of
embodiment, the downward movement of the piston being braked by
the FST X part, it is impossible for the manipulator to practice
too fast an injection, not giving time to the substances
to react with each other (with slight withdrawal of the piston in
end of injection to preserve the integrity of the handle).

In all embodiments, the material
plastic constituting the handle having a melting point
sufficiently low, it is not necessary to use chemical substances that are too concentrated or in too large a quantity,
although they are out of reach of the liquid to be injected.

Thus the criteria of the legisla
tion in the matter. This legislation is so diverse and shifting
that the exact nature of the chemicals used
(moreover "prior art" because falling under conventional concepts
cannot be specified a priori. It's about
comply with current legislation.

Figures 1 to 10 illustrate the invention:
Figure 1 shows a general view of the syringe
"chemical".

Figures 3,4, and 5 illustrate the mode of neutralization of the
syringe.

Figure 6 shows the multilevel reaction model
chemical.

 Figure 7 illustrates the paper strip model.

 Figure 8 shows the photo-sensitive chemical model.

Figure 9 shows the paper double crown model and
chemical reacting with air contanct.

 Figure 10 details, by a section, the double crown.

Figure 1 shows a general view of the syringe
according to the invention with, overcoming the piston head, the part in
form of section of FST tube (1) composed of two parts
nested.

Figure 2 shows a longitudinal section of the
lower part of the syringe with the step (2) which separates
the two parts, of different diameter, of the handle. In the hollow of
this step is hollowed out the gutter (3) where the crown is housed
of chemical substance A (4). A gutter (5) is dug, at the same
level, inside the wall of the handle. Exhibit FST 1 (1)
includes a step (6) carrying on its edge the layer of
chemical substance B (7). Room (8) communicates with the outside
by the longitudinal channel (9).

Figure 3 shows a longitudinal section of the
syringe in the aspiration phase. FST 1 is pushed towards
the top by the piston head.

Figure 4 shows the start of the push phase
injection. Chemicals A (4) and B (7) come into play
contact thanks to the bringing together of the two markets. The heat
resulting cuts the piston handle to a significant level
considerably thinned by the external circumferential gutters (3)
and internal (5). The piston can however continue to descend,
pushed by the stump of the piston handle.

Figure 5 shows that an aspiration attempt
in order to reuse the syringe is vain. The handle remains between the fingers of the manipulator.

 FIG. 6 shows the variant with two levels of upper (5) and lower (1) chemical reaction. Part FST 2 (10) is arranged accordingly, as is the handle.

 FIG. 7 illustrates the strip model of adhesive paper (11) carrying a line of chemical substance D (12) intended to react with the chemical substance E (13) applied to the upper and internal edge of the part FST 3 (14) .

 FIG. 8 shows the photo-sensitive chemical model (15) masked by the part FST 4 (16) before the use of the syringe.

 FIG. 9 shows, in longitudinal section, the chemical substance model (17) reacting on contact with air during the separation of the two paper renderers.

 FIG. 10 shows, in section, the two paper renderings glued respectively to the part FST 5 (20 and to the head of the piston by the adhesive layers (21) and (22). An air intake is made through the channels (23) (Fig: 9) opening through perforations (one of them in (24) opening the upper washer.

Claims (7)

- R E V E N D I C A T I O N S  1 - Medical syringe made of single-use plastic material which cannot be reused, according to the invention, the neutralization of which results from a chemical reaction which affects the handle of the piston.  Characterized in that the plunger handle is a fairly large plastic tube, the lower part (syringe described in vertical position, needle pointing down), overcoming the head on one or two centimeters, is narrowed. The passage from the upper part, wider, to the lower part, is made by a step (2) in the hollow of which a deep circumferential gutter is dug (3) to which responds, inside the handle, another gutter (5). This results in considerable thinning of the wall. A ring (torus) (4) of chemical A occupies the external gutter (3).  Characterized in that, surrounding the entire lower part and a few millimeters from the upper part of the handle, there is a piece in the form of a tube section (FST 1) (1) resting on the piston head and composed of two separate equal parts longitudinally (with a slight interlocking). This part is in the tight position in the lumen of the syringe. On the other hand, it is joined, but without any pressure, on the handle, according to a studied contiguity.  Characterized in that this contiguity is organized in the following manner, from bottom to top: over the greatest height of the narrowed lower part of the handle, and this up to a distance of a few millimeters from the crown of chemical substance A ( 4) this FST 1 piece (1) is adjacent to the handle. Then it sees its internal diameter suddenly increase by a step (6). This enlarged diameter is that of the rest of the part to which it allows to pass at a distance from the very upper part of the narrowed part of the handle and then to encas, over a few millimeters, the wide part of the handle on which it fits without pressure.  Characterized in that, on the upper edge of the step (6), appearing inside the part FST 1 (1), is spread a chemical substance B (7).  very low.  wall of the handle. This plastic at a melting point  plastic material at the level of the part, very thinned from the  sufficient heat to melt the  (4) and B (7) have the property of reacting to each other by producing  Characterized in that the chemical substances A  tance (in powder for example) intended to fight against humidity.  A (4) and B (7), is hermetically sealed and may contain a subs  between the steps (2) and (6) and containing the chemical substances  Characterized in that the small space (8) included  a little effort because it is tight in the syringe.  is pushed upwards by the piston head. Which requires  When pulling the suction piece FST 1 (1)  as follows :  Characterized in that its neutralization is done  plastic layer at the bottom of the gutter (3) containing the ring of chemical substance A (4). The handle is thus sectioned. So that the space (8) between the steps (2) and (6) does not form a compression chamber and thus does not compromise their coming together, the two half-pieces FST 1 (1) are crossed longitudinally in the middle by a channel (9) starting, at the bottom, at the level of the section placed on the head of the piston and ending at the top in the middle of the horizontal face of the step (6). B (7), hence the production of heat and fusion of the very thin  chemical A (4) then reacts with the chemical layer  of FST 1 (1) facing it. The Crown of Substance  then the sleeve (2) of the handle comes into contact with the sleeve (6)  of the piston descends, alone, over a distance of a few millimeters  At the start of the push on the handle the head  only then.  channel (9) and puts the classic space (8) in communication with the outside  The piston head, going down, releases the lower opening of the  upper part FST 1 (1).  handle is sheathed, therefore stabilized in the thinned part  normal mechanical because the upper, widest part of the  the descent of the piston can continue under conditions  Although its handle is cut in two parts  fingers.  liquid is no longer possible because, if the manipulator pulls on the handle, the upper part of it remains between the  Whether the injection is finished or not, no  neutralization of the syringe.  inject too quickly to try to avoid  light from the syringe, it is impossible for the manipulator to  piston being braked by part FST 1 (1) clamped in the  Characterized in that, the downward movement of the  2 - Syringe according to claim 1 characterized  in that the piston handle and the part FST 2 (10) comprise  several steps opposite, with as many layers of subs  chemical tances.  the gutters dug in the wall, and future sites of thermal cutting.  differential exceeding a few millimeters above and below  weakened by a vertical precut with a circumferential layout  Characterized in that the handle is, moreover,  3 - Syringe according to claim 1 or 2 character  laughed at in that the chemicals and the nature of the  material, plastic constituting the handle are studied for  allow, during the "chemical contact", a sectioning of the handle  based on a specific chemical action (solubilization, extreme  embrittlement, crystallization) and not (or not exclusively)  thermal.  4 - Syringe according to claim 1 characterized  in that the piston handle is made up of two parts  separate joined by gluing a strip of paper  adhesive (11) of sufficient tensile strength, but special  also studied in the sense of great vulnerability to  future chemical reaction.  handle is slightly larger in diameter.  Characterized in that the upper part of the  runs a thin line of chemical D (12).  level of the line of separation of the two parts of the handle,  CAracterized in that, on paper, exactly at  meters from the chemical line D (12).  lower part of the handle up to a distance of a few milli  includes no upper shrink here, string the  Characterized in that the part FST 3 (14), which does not  which is then sectioned.  injection boost, with chemical substance D (12) from the paper,  chemical substance E (13) intended to react, from the start of the  internal part FST 3 (14) is applied a layer of  Characterized in that, on the upper edge and  FST 3 (14).  piston handle, being wider, does not allow the workpiece  Characterized in that, the upper part of the  5 - Syringe according to claim 1 characterized  in that a special photosensitive chemical substance (15) is  distributed at the base of the plunger handle, flush with the head, in  a deep circumferential gutter. She is masked by  an FST 4 piece (16) clamped in the lumen of the syringe and  resting on the piston head. Piston and part FST 4 (16) are  black in color.  the piston head is thus separated from the handle.  thinned at the bottom of the circumferential gutter. The  melt the plastic at a very low melting point) very  reaction is producing enough heat to make  the light which acts on the photosensitive substance (15), the  injection piece FST 4 (16) remains high and lets through  Characterized in that, at the start of the push  6 - Syringe according to claim 5 characterized  in that the chemical (17) reacts on contact with air  which slides between a FST 5 piece (20) perforated longitudinally (23) and the piston head, at the start of the thrust  injection.  separated from the start of the push. The injection.  (lower (19), at the piston head. The two washers are  one (the upper one (18), in room FST 5 (20), and the other  called together but strongly adhering (calle (21) and (22),  between two paper washers (18) and (19) weakly  Characterized in that the substance used is  7 - Syringe according to claim 7 characterized in that the chemical substance is an appropriate mixture of two thermally reacting substances, one to light, the other to contact with air. These two substances are also included between two paper discs.