GB2204098A - Closure plug - Google Patents

Abstract

A closure plug 10 for a cylindrical tube containing, say, a blood sample has a stepped wall 11, 12 to permit evacuation of the tube as the plug is inserted in its open end. A specimen of liquid may be introduced into the evacuated tube through a diaphragm 18 in the plug using a hypodermic needle. A sample of the liquid specimen may be drawn up into an open-ended sample tube 60 by driving the sample tube through a circular line of weakness 19 in the diaphragm whereupon the sample tube displaces from the plug an axially apertured 21 a piston 20 which is driven down the specimen tube by the sample tube to drive specimen liquid through the aperture and up the sample tube from its open end. <IMAGE>

Description

CLOSURE PLUG This invention relates to a plug for sealing a bottle, vessel or other container, which plug is arranged tb be pierced by a tube for drawing a column of liquid into the tube from within the bottle etc. The plug has particular utility in the medical field.

It is known in the medical field to obtain a sample of blood in a container, sealed by a closure plug, then to pierce the closure plug with one end of a glass sample tube and to draw a column of blood from the container up the sample tube by applying suction to its other end.

Known sedimentation tests are then carried out on the column of blood thus provided in the glass sample tube. However the separate steps of piercing the closure plug with the sample tube and applying suction to the upper end of the sample tube are required.

I have now devised a closure plug enabling a column of liquid to be drawn into a sample tube simply by piercing the closure plug of a container with the sample tube and continuing to push the sample tube through the closure plug and into the container.

In accordance with this invention, there is provided a closure plug for sealing a bottle, vessel or other container, the closure plug being formed with a diaphragm which can be pierced by a sample tube and the closure plug being provided with a piston member which can be separated from the closure plug by pushing the sample tube through the closure plug after piercing said diaphragm, which piston member forms a piston relative to said bottle, vessel or other container and displaces liquid in said bottle etc.

through an aperture in said piston member and up the sample tube as the piston member is pushed into said bottle etc. by said sample tube.

Preferably the closure plug is arranged to enable evacuation of the bottle etc. so that the bottle etc. will draw the sample of blood or other liquid into itself by suction through a fine tube or -needle if the latter is pierced through the plug. Preferably the closure plug is arranged to seat in the open top of the bottle etc. whilst leaving a clearance for enabling evacuation of the bottle etc., the plug being capable of then being pushed inwardly to seal the top of the bottle etc. This plug then enables a sample of blood to be drawn directly into the bottle etc.

from the patient, and subsequently the column of blood to be drawn from the bottle by pushing a sample tube through the closure plug, without any need to remove the closure plug and without any need to transfer blood from one container to another, thus simplifying the processes but also avoiding the risk of people carrying out the processes coming into contact with the blood itself.

An embodiment of this invention will now be described by way of example only and with reference to the accompanying drawings, in which: FIGURE 1 is a part-side view, part-longitudinal section of a closure plug in accordance with this invention; FIGURE 2 is a section through part of an apparatus serving to evacuate a container and then push the closure plug inwardly to seal the container; and FIGURE 3 is a side view of a container sealed by the closure plug of Figure 1 and containing a blood sample and showing a glass sample tube being pushed through closure plug to cause a column of blood to be drawn into the sample tube.

Referring to Figure 1 of the drawings, there is shown a generaly tubular closure plug 10 formed of resilient rubber or plastics material. The plug 10 comprises a middle section 11 with a plain generally cylindrical outer surface, a reduced-diameter lower section 12 joined to the middle section 11 by a chamfered or conical transition 13, and a larger-diameter upper section 14 presenting an annular flange 15 for sitting on the rim of a container which the plug is to close. The lower section 12 is provided with a series of vertical ribs 16 (e.g. 4 ribs) equally spaced around the circumference and projecting from the otherwise generally cylindrical outer surface of this section, but not projecting radially as far as the outer surface of the middle section 11 of the plug.The plug 10 is formed with a cylindrical passage 17 extending along its axis from its top end to its lower end, but this passage 17 is closed by a thin diaphragm 18 adjacent the top of the plug. This diaphragm 18 may be pierced by a sharp needle, for the purpose of drawing blood through the needle and into an evacuated container closed by the plug: when such a needle is ten withdrawn from the plug, the resilient nature of the material of which the plug is made ensures that the diaphragm will re-seal.The diaphragm 18 is further weakened along a circular line so that it can be pierced readily by a glass sample tube, as will be described with reference to Figure 3: thus a circular groove 19 is formed in the upper surface of the diaphragm 18 and a corresponding groove 19a is formed in the lower surface of the diaphragm (but does not extend for quite the full 3600).

A piston member 20 is engaged into the. lower end of the closure plug 10 as shown in Figure 1. Piston member 20 has a disc-shaped portion 21 and a tubular stem 22 projecting from it. The disc-shaped portion 21 is formed with an aperture 21a communicating with the longitudinal passage 22a of the stem 22. A rib 17a is formed around the passage 17 of the plug 10 and a rib 23 is formed around the stem 22 of the piston element. The piston member 20 is pushed into the lower end of the passage 17 of the plug 10 until rib 23 of the piston member lies above the rib 17a of the plug, engaging the two members together. The lower surface of the piston member is domed as shown.By pushing the piston member into the plug so far that its rib 23 lies above the rib 17a of the plug, the disc-shaped portion 21 is itself drawn slightly into the passage 17, with the effect of reducing the overall diameter of the disc-shaped portion 21 at this time.

Referring to Figure 2 of the drawings, the closure plug of Figure 1 is shown seated in the open top of a container 30 in the form of a glass tube. Thus the plug 10 sits with its lower section 12 pushed into the container 30, the ribs 16 ensuring that this lower section is a push-fit into the tube 30 but also ensuring that a clearance is maintained between the outer surface of the plug and the inner surface of the tube 30 at this time. Also, because the discshaped portion 21 of the piston member has been drawn slightly into the plug passage 17, causing a slight reduction in its overall diameter as described above, there is a clearance between the periphery of the disc-shaped portion 21 and the inner surface of the tube 30. In this position of the plug, the tube 30 can be evacuated, but then the plug can be pushed inwardly in order for its middle section 11 to become positioned in the open top of the tube 30, thus sealing the latter.

In order to evacuate and seal the tube 30, firstly the plug is applied to the tube to the position shown in Figure 2, that is to say with just the lower section 12 within the tube. Then the tube 30, with the closure plug, is placed in a tubular carrier 40 as shown. A modification of the apparatus disclosed in my British patent application No. 8520785 (which is herein incorporated by reference) is used for evacuating the tube 30 and then pushing the plug inwardly to seal the tube. Firstly the tubular carrier 40, carrying the tube 30 and closure plug as shown, is placed on a platform 51 of the apparatus below a plunger assembly 52,54. Then e.g. by operating a manual lever, the assembly 52,54 is lowered so as to urge the rim of a tubular member 52 onto the rim of the carrier 40, thus closing the top of the latter in a sealing manner.Continued movement of the operating lever of the apparatus displaces a piston in a piston-and-cylinder suction actuator, to apply suction through the tubular plunger 54 and thus evacuate the space at the bottom of member 52 and also evacuate the tubular carrier 40 and the tube 30. In a final portion of movement of the operating lever of the apparatus, the plunger 54 is displaced downwardly relative to the tubular member 52, and its enlarged lower end 53 bears on the top of the plug to push it downwardly and to its sealing position within the tube 30. The operating lever of the apparatus is then allowed to return to its initial position and the carrier 40 is removed from the apparatus and the sealed tube 30 is removed from the carrier 40.

The sealed and evacuated tube 30 can now be used to draw into itself a sample of blood, by piercing the diaphragm 18 of the plug with one end of a fine needle so as to apply suction to this end of the needle and draw blood through the needle from its other end and into the tube 30. When the needle is then withdrawn from the diaphragm 18, the latter re-seals under the resiliency of the material from which it is made. The piston member 20 has so far remained engaged with the lower end of the plug 10.

Figure 3 shows a column of blood being drawn into a glass sample tube 60 from the container tube 30. The lower end of the sample tube 60 is pushed against the top of the diaphragm 18 so as to pierce this by causing rupture along the lines of weakness 19,19a. However, the circular piece of diaphragm 18 which is bounded by the circular lines 19, 19a remains attached to the surrounding portion of the diaphragm, by the portion which interrupts the line 19a.

The sample tube 60 is a sealing fit within the aperture now formed in the diaphragm 18, and is now pushed through this aperture so as firstly to engage the piston member 20 and then to displace member 20 and disengage it from the plug 10. The disc-shaped portion 21 of the piston member is now free to expand into sealing engagement with the inner surface of the container tube 30, and it now forms a piston relative to the tube 30. Continued inward movement of the sample tube 60 displaces the piston member downwards to eventually contact the blood 70 and force this through the aperture 21a in the piston member and up the sample tube 60. The domed lower surface of the portion 21 ensures that the air will be expelled before blood starts to displace from the container 30. The movement of the sample tube 60 is stopped when a column of blood of the required height has been obtained in the tube 60.

The closure plug which has been described thus enables a column of blood or other liquid to be bbtained in a simple manner, by pushing a rigid sample tube through the closure plug and using it to drive the piston member so that a single operation both inserts the sample tube and obtains the column. The preferred embodiment which has been described has the additional advantage that it enables preevacuation of the container in a simple and reliable manner, and then enables blood to be drawn into the container directly from the patient and then the column of blood to be obtained, without any risk of the people carrying out these processes coming into contact with the blood.

Claims (7)

1. A closure plug for sealing the open end of a cylindrical container, the plug having a diaphragm which can be pierced by an open-ended sample tube and an apertured piston member which can be separated from the remainder of the plug by pressure applied to it by the sample tube as the tube extends through the diaphragm, said displaced piston member being capable of forming a sliding seal with the inside wall surface of the container to displace progressively any fluid in said container, via the aperture in the piston member, into the sample tube.

2. A closure plug as claimed in claim 1 adapted to permit evacuation of the container during seating of the plug in the open end of the container.

3. A closure plug as claimed in claim 2 wherein the plug has a stepped wall surface with a relatively small diameter end section to mate with the container end during said evacuation and a relatively large diameter intermediate section for sealing with said container following said evacuation.

4. A closure plug as claimed in claim 3 wherein the end section has a plurality of axially-extending radially outwardly projecting ribs.

5. A closure plug as claimed in any one of claims 1 to 4 wherein the diaphragm has an incomplete circle of weakness, permitting the sample tube to part the diaphragm along said line of weakness and cause the parted circular portion to be displaced by pivoting around the remaining, unweakened arc of the circle defined by the line of weakness.

6. A closure plug as claimed in any one of the preceeding claims wherein the piston member is resilient and elastically movable between an indrawn disposition in which it is resiliently engaged with the remainder of the plug and has a relatively small diameter, and a deployed, sweeping disposition detached from the remainder of the plug and has a relatively large diameter, the said engagement being responsible for the reduction in the diameter of the piston member.

7. A closure plug substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.