Apparatus for determining and recording injection doses in syringes using electrical capacitance measurements
First Claim
1. In combination with a syringe, an apparatus for determining and recording a dose of an agent delivered with said syringe, said syringe being of the type comprising:
- a) a barrel for holding said agent;
b) a plunger movably positioned in said barrel for expelling said agent;
c) a capacitive element comprising a first conducting surface coupled to said barrel and a second conducting surface coupled to said plunger for mutual movement therewith such that the distance between said first conducting surface and said second conducting surface varies in dependence upon the position of said plunger inside said barrel;
d) an input terminal located on the outside of said syringe and electrically connected to said first conducting surface;
e) an output terminal located on the outside of said syringe and electrically connected to said second conducting surface;
said apparatus comprising;
a) a housing;
b) a field on the outside of said housing, said field having an input contact for contacting said input terminal and an output contact for contacting said output terminal;
c) a voltage generating means for producing a voltage difference across said input contact and said output contact, thereby charging said capacitive element when said input contact is contacting said input terminal and said output contact is contacting said output terminal;
d) a measuring means connected to said input contact and said output contact for measuring the capacitance of said capacitive element and for calculating from the capacitance said dose; and
e) a recording means connected to said measuring means for recording said dose.
3 Assignments
0 Petitions
Accused Products
Abstract
An apparatus for electrically determining and recording the dose of an agent delivered with a syringe of the type having a barrel for holding the agent and a plunger for expelling the agent. The syringe includes a capacitive element having first and second conducting surfaces arranged such that the capacitance of the capacitive element varies in dependence upon the dose of agent contained in the barrel. An input terminal and an output terminal located on the outside of the syringe are electrically connected to the first and second conducting surfaces, respectively. The apparatus produces a voltage difference across the terminals, thereby charging the capacitive element. A capacitance meter measures the capacitance and a microprocessor calculates the dose from the measured capacitance. The calculated dose is recorded by a digital memory unit.
487 Citations
24 Claims
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1. In combination with a syringe, an apparatus for determining and recording a dose of an agent delivered with said syringe, said syringe being of the type comprising:
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a) a barrel for holding said agent; b) a plunger movably positioned in said barrel for expelling said agent; c) a capacitive element comprising a first conducting surface coupled to said barrel and a second conducting surface coupled to said plunger for mutual movement therewith such that the distance between said first conducting surface and said second conducting surface varies in dependence upon the position of said plunger inside said barrel; d) an input terminal located on the outside of said syringe and electrically connected to said first conducting surface; e) an output terminal located on the outside of said syringe and electrically connected to said second conducting surface; said apparatus comprising; a) a housing; b) a field on the outside of said housing, said field having an input contact for contacting said input terminal and an output contact for contacting said output terminal; c) a voltage generating means for producing a voltage difference across said input contact and said output contact, thereby charging said capacitive element when said input contact is contacting said input terminal and said output contact is contacting said output terminal; d) a measuring means connected to said input contact and said output contact for measuring the capacitance of said capacitive element and for calculating from the capacitance said dose; and e) a recording means connected to said measuring means for recording said dose. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. In combination with a syringe, an apparatus for determining and recording a dose of an agent delivered with said syringe, said syringe being of the type comprising:
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a) a barrel for holding said agent; b) a plunger movably positioned in said barrel for expelling said agent; c) a capacitive element comprising a first conducting surface coupled to one side of said barrel and a second conducting surface coupled to the opposite side of said barrel such that the capacitance of said capacitive element varies in dependence upon the volume of said dose contained in said barrel; d) an input terminal located on the outside of said syringe and electrically connected to said first conducting surface; e) an output terminal located on the outside of said syringe and electrically connected to said second conducting surface; said apparatus comprising; a) a housing; b) a field on the outside of said housing, said field having an input contact for contacting said input terminal and an output contact for contacting said output terminal; c) a voltage generating means for producing a voltage difference across said input contact and said output contact, thereby charging said capacitive element when said input contact is contacting said input terminal and said output contact is contacting said output terminal; d) a measuring means connected to said input contact and said output contact for measuring the capacitance of said capacitive element and for calculating from the capacitance said dose; and e) a recording means connected to said measuring means for recording said dose. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification