Patent ID: 12187994

DETAILED DESCRIPTION

The preferred embodiment and other embodiments, which can be used in industry and include the best mode now known of carrying out the invention, are hereby described in detail with reference to the drawings. Further embodiments, features and advantages will become apparent from the ensuing description, or may be learned without undue experimentation. The figures are not necessarily drawn to scale, except where otherwise indicated. The following description of embodiments, even if phrased in terms of “the invention” or what the embodiment “is,” is not to be taken in a limiting sense, but describes the manner and process of making and using the invention. The coverage of this patent will be described in the claims. The order in which steps are listed in the claims does not necessarily indicate that the steps must be performed in that order.

An embodiment of the present invention generally provides a plastic culture tube with screw cap, where there may be two positions for the cap on the tube that relate to air-flow. The first position snaps the cap onto the tube, but still allows air-flow into the culture tube. When the cap is further twisted, the tube fully closes into an air-tight seal. Embodiments of the present invention may set up an aerobic/anaerobic culture environment using a multiple position screw thread, without requiring an up-and-down snap cap. Embodiments may have various plastic materials in at least two sizes, including 12×75 mm or 17×100 mm tubes with appropriately-sized caps.

In an embodiment, the user may place a cap on to the threaded end of a culture tube and begin to turn the cap clockwise. An area of friction (a first “bump”) may be felt very soon into the first turn. Once that area of friction is past, the cap may now be firmly attached in an aerobic position to allow breathing of the tube's contents. The cap will tend not to fall off, be shaken off, or become otherwise detached. Embodiments may allow air to flow in and out of the tube, and if turned upside down, the liquid may slowly spill out. If one continues turning the cap an additional few degrees, a second area of friction may be felt. Turning past that second bump may allow the user to continue turning another half turn, at which point the cap may form an airtight and liquid-tight seal like any ordinary screw cap.

In an embodiment, before a cap-and-tube system is in the first position, a user may put the cap on the tube and then turn the screw cap down onto the tube until the user feels the first area of friction (resistance to turning the cap). When the user turns the cap further, the snapping ring is forced into the ring grove, causing a clicking noise and a sudden release of resistance. The user can easily tell when the cap is snapped into the first position. The cap (in the first position) is attached to the tube, but there is still an airway to the contents of the test tube. If the tube were set on its side or dumped over, the contents of the tube would probably spill out.

In an embodiment, the user may initially start to screw the cap onto the tube (“zero” position). In the first position, the snapping ring holds the cap at a precise distance so that air flows from the outside into the tube (perhaps according to FDA regulations). The snapping ring on the tube will snap into the snap groove of the cap, then pop out of the groove and into the snap ring chamber, and then travel up (not necessarily to the top). The ring of the tube will stop travelling upwards in the cap chamber when the tube rim meets the cap underside, resulting in the sealed position of the culture system. In this second position, the cap may form a seal with a mating ring on the underside of the cap. The mating ring extension to the cap may provide additional surface area to enhance contact and improve the seal between the cap and tube.

In embodiments, the first frictional position is secure, but not air tight. This is because there is a clearance between the tube rim and underside of the cap. A snap groove (a radial, uniform groove on the circular inside surface of the cap) holds the cap to the snapping ring on the tube, but also provides an airway. Air can flow into the tube through the first-position cap clearance, and also through the recesses in the snapping ring. The tube contents are open to the air until the user snaps it out of the first position, further twists the cap, and seals the system in a second position. The user can tell when the cap is tight (as in a typical screw cap) from the increased resistance to tightening.

Embodiments of a plastic cap may be reinforced around the snap groove, to provide support and room for the snapping ring.

Embodiments of caps may have ridges or small flanges on the outside, to help the user twist the cap.

Embodiments of the tube rim and cap underside may be flat, and the screw threads of the tube (tube threads) may correspond to and engage with the screw threads of the cap (cap threads). This may be consistent with commercial standards for flightings and threads of existing screw-caps and culture tubes.

Embodiments may give an additional visual indication to the user as to whether the system is in an aerobic or anaerobic position.

Embodiments of a two-position system, capable of both anaerobic and aerobic uses, may comply with standards for culture tube sizes and the machines that utilize test tubes. Embodiments may include (for example) 12×75 mm or 17×100 mm tubes.

FIG.1depicts an embodiment of a cap10and a tube20. Cap10may have an underside12, interior cap threads14which go down part of the way down the interior side of the cap, a snap ring chamber16, and a snap groove18near the bottom. Tube20may have tube rim22, tube walls24with exterior tube threads26, and a snapping ring28.

FIG.2depicts an embodiment of a cap10having a mating ring30on the cap underside that fits inside tube20to form the seal with the tube rim22. Embodiments of a tube20may have recesses32or other aerobic clearances on the snapping ring28and tube threads26, to form an air-path up the side of the tube to the tube rim.

FIG.3Adepicts tube20with a cap10attached in a first, aerobic position, having a clearance34at the top of the tube. Snapping ring28is engaged with tube rim22, yet the structure keeps a clear air-path so air can still get into the test tube. The structure alongside the walls of the tube keeps an open air-path, so the system is ready for aerobic (with-air) culturing.

FIG.3Bdepicts the tube and cap system, which may be twisted into either an aerobic or anaerobic position without completely opening the tube.

FIG.4depicts a tube20and cap10in an unsecured, fully-open position (depicted on the left), transitioning into a secured-but-aerobic position (right). On the left, snapping ring28of the tube is not yet engaged with snap groove18of the cap. On the right, the snapping ring28has been forced by the user into the first groove. The aerobic position (right) still has an aerobic clearance34at the top of the tube, because the snap groove18holds the snapping ring28in place, and the cap will not screw down any lower without the user feeling that the cap is going past the snap.

FIG.5depicts embodiments of recesses in the snapping ring. A preferred embodiment has two recesses34in the threads and flightings on the sides of the snapping ring28, which engage with the interior cap threads but keep an air pathway alongside the tube. The recesses34provide an aerobic air pathway alongside the walls of the tube24and the cap10. The pathway may be sealed by further twisting the cap and closing the top of the tube, but if there is a clearance at the top, the air pathway to the contents of the tube remains open.

FIG.6depicts a tube20and cap10in a secured-but-aerobic position (left) transitioning into a fully-sealed-anaerobic (right) position. The left side ofFIG.6is the same as the right-side ofFIG.4, where the snapping ring28on the tube is engaged with the snap groove18of the cap. There is a clearance34at the top of the tube. The snap ring chamber16is empty.

The right side ofFIG.6shows that the cap10has been screwed further down onto tube20, so that snap groove18and snapping ring28have disengaged. The snapping ring28is in the snap ring chamber16of the cap, and if the user twists the cap, the snapping ring28(a flange partway down the exterior of the tube) will slide up and down within the snap ring chamber16(an open area inside the cap between the ring groove and the cap threads). When tube10rises, tube rim22will approach cap underside12. When the clearance34at the top of the tube is eliminated, the cap and tube will press flush together to create second position having an air-tight seal. The user can detect this second position from the resistance to torque which happens when any screw-cap is twisted until tight.

FIG.7shows a cap10screwed all the way into an anaerobic position. Cap underside12may have a plastic, flexible mating ring30that engages with tube20and forms a seal with tube rim22. Snapping ring28on the tube may be retained within ring chamber16of the cap, preferably near or at the top of the chamber.