Claims
- 1. A device for facilitating the transfer of the contents of a tubular receptacle having an axis to a fluid suction member, the suction member having a suction chamber and stem communicating with the chamber, the receptacle having an open end sealably closed by an injectable closure, said device comprising:
- a cannula having an axis and adapted to pierce a closure and having a passageway adapted to pass
- a suction member stem through the closure and vent the interior of 9 receptacle to the atmosphere,
- the cannula having an outer shroud with an axis, said shroud adapted to slide over an open receptacle end to guide the cannula during piercing,
- the cannula having a pointed tip defined by a generally planar cut slanted to the cannula axis to form an acute angle for piercing the closure,
- the cannula being positioned parallel to and off-center from the shroud axis in a position opposite to the direction of the taper of the point of the cannula to compensate for the sideways movement created during piercing the closure and to cause the cannula tip to be located approximately on the receptacle axis after piercing.
- 2. A device set forth in claim 1 wherein the cannula has a penetrable, reclosable member closing the passageway and the shroud has an upper flange defining a cuplike receptacle and which device also includes an annular retainer positioned in said cuplike receptacle securing the penetrable member in the passageway.
- 3. A device set forth in claim 2 wherein the shroud has an inner wall with axial ribs to position the shroud relative to the receptacle.
- 4. A device set forth in claim 2 wherein the flange has an inside wall with a ring-groove formed therein and the retainer has an outside wall with dimples formed thereon adapted to engage the ring-groove in a detent-like action to maintain the retainer in position and wherein the shroud inner wall defines axial ribs to position the shroud relative to the receptacle.
- 5. A device for facilitating the transfer of the contents of a tubular receptacle having an axis to a fluid suction member, the suction member having a suction chamber and stem communicating with the chamber, the receptacle having an open end, said device comprising:
- an injectible closure positioned in an open end of a receptacle,
- a cannula having an axis and adapted to pierce the closure and having a passageway adapted to pass a suction member stem through the closure and vent the interior of the receptacle to the atmosphere,
- the cannula having an outer shroud with an axis, said shroud adapted to slide over the open receptacle end to guide the cannula during piercing,
- the cannula having a pointed tip defined by a generally planar cut slanted to the cannula axis to form an acute angle for piercing the closure,
- the cannula being positioned parallel to and off-center from the shroud axis in a position opposite to the direction of the taper of the point of
- the cannula to compensate for the sideways movement created during piercing the closure and to cause the cannula tip to be located approximately on the receptacle axis after piercing.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part of an application Ser. No. 494,300 filed May 13, 1983, now abandoned.
This invention relates to a novel method and device for transferring fluids from a sealed receptacle to successive suction devices.
In the clinical and biological research fields various devices have been constructed for receiving a sample of a fluid under test, separating the components of the fluid and separately withdrawing the components for further test and analysis. One such device is described in U.S. Pat. No. 4,212,948 issued July 15, 1980 to Gordon L. Dorn. The Dorn patent describes a technique for selectively separating microorganisms from any anti-microbial factors in a sample fluid such as a lysed blood sample. The blood sample is injected into a sterile confined zone containing both a cushioning agent and a lysing agent. The lysed blood sample is then centrifuged such that the microbial pathogens will pass out of suspension and collect in a layer adjacent the interface of the cushioning agent and the blood sample itself.
To facilitate removal of the separated sample components, a centrifuge receptacle having both top and bottom injectable stoppers or closures is used. The inner surface of the bottom closure is positioned at an angle which is a complement of the angle at which centrifugation is to be performed. Next a vent needle is inserted through the top closure, a second hypodermic needle with suction device or syringe attached is inserted through the bottom closure to a distance beyond the separated microbial pathogens into the residual blood sample which is then withdrawn. After vortexing, a second hypodermic needle with syringe is injected through the bottom closure to a distance immediately adjacent the inner surface of the bottom closure and the microbial pathogens removed and subjected to further test.
While the separation procedure described by Dorn is excellent, it does have certain disadvantages. For one, it requires extensive manipulation of two separate syringes and a third vent tube needle. Further the bottom entry approach can cause "bulging" of the cushioning layer and a remixing of the separated microbial pathogens with residual blood. This tends to defeat to some extent the entire purpose of the centrifugal separation.
Other devices are known which are capable of transfering fluid from a source into fluid collection containers. One such device is described in U.S. Pat. No. 3,608,550 issued Sept. 28, 1971 to Stawski. Stawski proposes using a cannula to pierce the rubber stopper of a fluid container. This cannula is of sufficient internal diameter so that a second cannula may be inserted through the first cannual and yet provide an air vent for the fluid container. A syringe is connected to the second cannula for each sample fraction to be withdrawn. While suitable, this structure is relatively complex requiring two components plus a plurality of syringes for each fluid container. Furthermore, it is not adapted to pierce relatively heavy rubber stoppers which are of sufficient thickness to maintain a vacuum within a tube as in the Dorn tube. Careful quidance is needed for the cannula in order to pierce the rubber stopper accurately along the axis of the fluid container.
Scislowicz in his U.S. Pat. No. 3,206,073 describes a dispensing container having a plastic spout adapted to pierce a rubber stopper 34. Even here the piercing of the stopper 34 is difficult to achieve in an accurate manner since there is no guidance provided and would be most difficult if the event it were used to pierce relatively thick rubber stoppers.
Many of the disadvantages of these prior art devices for transferring the contents of a receptacle to various suction devices are averted by the use of top entry procedures for accessing the interior of the receptacle and withdrawing its several contents using plastic transfer pipettes. More specifically, a device is constructed in accordance with this invention for facilitating the transfer of the contents of a receptacle to at least a pair of successive fluid suction members. Each suction member has a suction chamber and a stem communicating with the chamber. The receptacle has a open end sealably enclosed by an injectable closure. The transfer device includes a cannula adapted to pierce the closure. The cannula has a passageway adapted to pass a suction member stem through the closure and at the same time vent the interior of the receptacle to the atmosphere. Also, the cannula has an outer shroud adapted to slide over the open receptacle end closure to guide the cannula during penetration.
Preferably the cannula is formed of a rigid plastic with a sharpened tip capable of piercing the closure without causing "coring". This is a common occurrence with syringes of larger diameter as is required to permit the passage of a still thinner needle or stem therethrough. The cannula and shroud are integral. A suitable rigid plastic may be used such as an acetal resin or nylon. The shroud has an inside diameter greater than the outside diameter of the closure to facilitate expansion of the closure during the piercing operation. Also the shroud has a lower end with an internal flange adapted to engage lightly the closure for positioning the transfer device over the closure prior to piercing.
The fluid suction members are pipettes having an integral hollow bulb and a connected hollow stem. They also are constructed of a flexible plastic material. One of the pipettes has a stem of a length less than that of the receptacle such that it may be inserted through the cannula only to a distance capable of removing the residual blood and incapable of dipping down into the separated microbial pathogens. The second pipette has a length typically slightly greater than that of the receptacle plus closure so that it may extend to the very bottom of the receptacle and remove the microbial pathogens. To facilitate such removal when a tapered, bottom stopper is used, as described in the Dorn patent, the stem should be flexible to permit its bending over to the periphery of the tube-receptacle where the angled bottom stopper engages the sidewall of the tube. The ends of the stems may be rounded to facilitate their use. The hollow bulbs of the pipettes may be sized to accommodate the amount of fluid it is desired to withdraw.
In an alternative embodiment of the invention, the cannula is positioned off the axis of the shroud in a direction opposite that of the point of the cannula. This compensates for the tendency of the plastic cannula to offset in the direction of the angled cannula tip during piercing.
Using the transfer device of this invention greatly facilitates the removal of successive fractions of fluids from a receptacle. With this device, the shroud is first easily and lightly fitted over the receptacle top closure. The internal flange of the shroud facilitates this by engaging the exterior of the closure and holds the transfer device in position until the closure can be pierced. Piercing preferably is accomplished using a press although it can be accomplished by hand. During piercing, the cannula is guided by the transfer devices shroud which fits over the closure and receptacle. Following piercing, one of the suction members is inserted into the receptacle through the cannula and fluid is withdrawn. Next the one suction member is withdrawn and a second suction member is filled in a similar manner. Thus the several fractions can be removed each using a separate suction member in succession.
In an alternative embodiment of the inventors, the transfer device is provided with a septum in the cannula. This aids in containing aerosols within the receptacle and wiping the exterior surface of the pipette stem. The septum may be formed of a suitable foam or other compliant material that when precut provides easy access for the pipette stem.
US Referenced Citations (14)
Foreign Referenced Citations (4)
| Number |
Date |
Country |
| 468683 |
Jan 1952 |
ITX |
| 673281 |
Jun 1952 |
GBX |
| 2025858A |
Jan 1980 |
GBX |
| 2026992 |
Feb 1980 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
494300 |
May 1983 |
|
Patent Grant
4808381
