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Bi-Directional Ratchet Syringe

Make syringes more useful
  [vote for,

Syringes are widely used. Within the medical field, predictably, and elsewhere. This is because they're dirt cheap positive displacement pumps available in all sorts of convenient sizes, with nice connectors and valves available to fit. Sometimes, it's useful to apply pressure, or selective vacuum to a syringe. Pull a slight vacuum to encourage blood to fill the barrel, or apply positive pressure to a gas-liquid mix in the barrel to force the liquid through a filter, for example. This can get tiring on the hands.

So, let's improve it. On the plunger, specifically on the + section part between the thumb pad and the rubber seal, there should be a toothed section. Possibly cut into one, or all four of the ends of the = cross section. Next, there should be two simple, plastic flexible ratchet teeth mounted on the barrel component. One should allow free movement in but not out, and the other out but not in. The plunger teeth and the ratchet component should be engaged or disengaged by simply rotating the plunger within the barrel. Hope that's clear.

bs0u0155, Apr 21 2015

Syringe gun ratchet action http://www.adhesive...s.co.uk/syrguns.htm
Unidirectional only, however. Your idea is better bs. [bhumphrys, Apr 22 2015]


       //Sometimes, it's useful to apply pressure, or selective to a syringe.// I was following up to that point.   

       Apart from that - yes, sort of. But only useful (as you note) when the barrel contains some gas.
MaxwellBuchanan, Apr 21 2015

       fixed. This idea was inspired by the Qiagen Maxi kit. Designed by torturers or incompetents, can't decide.   

       //But only useful (as you note) when the barrel contains some gas//   

       Not with the vacuum. There's plenty of times when you might want to pull a vacuum and then open a tap somewhere else. Vacutainers are essentially an expensive pre-vacuumed syringe.
bs0u0155, Apr 21 2015

       //Not with the vacuum.//   

       Yes, I suppose so.   

       (Only ever used Qiagen mini and midis; the midi is a waste of time as it's far quicker to do 10 minis.)
MaxwellBuchanan, Apr 21 2015

       On reflection, [+] because it should be possible to do this just by slightly altering the existing plastic components.   

       The plunger rotation (to engage either the "forward" or "reverse" ratchet) should require a definite positive action, with the syringe initially being in a "no ratchet" position. I can imagine, if not, that the feature could be annoying to people using syringes ratchetlessly* routinely.   

       *As far as I can ascertain, this is the first appearance on the interweb of the word "ratchetlessly". You heard it here first.
MaxwellBuchanan, Apr 22 2015


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