US 5,782,814 AGranted

Apparatus for determining and recording injection doses in syringes using electrical inductance

AssigneeRaya Systems, Inc.

InventorsStephen J. Brown, Erik K. Jensen

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Abstract

An apparatus for determining and recording a dose of an agent delivered with a syringe. The syringe has a barrel for holding the agent and a plunger movably positioned in the barrel for expelling the agent. The plunger includes a magnetically responsive element, such as an iron core. The apparatus has a receptacle for receiving the syringe for dose measurement. An inductive element is positioned coaxially to the receptacle to produce a magnetic field. When the syringe is placed in the receptacle, the intensity of the magnetic field varies in dependence upon the position of the plunger in the barrel. The magnetic field induces a voltage in a conducting loop. A voltage meter is connected to the conducting loop to measure the induced voltage. A microprocessor is connected to the voltage meter to calculate the dose from the measurement of the induced voltage. A recorder, such as a digital memory unit, records the dose.

Claims32

Dependent claims

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, said plunger comprising a magnetically responsive element selected from the group consisting of diamagnetic materials and paramagnetic materials;
c) an inductive element for generating a magnetic field, said inductive element being coupled to said barrel such that the intensity of said magnetic field varies in dependence upon the position of said plunger in said barrel, and said inductive element having a first terminal and a second terminal;
d) an input terminal located on the outside of said syringe and electrically connected to said first terminal;
e) an output terminal located on the outside of said syringe and electrically connected to said second terminal;
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 causing an electric current to flow through said inductive element when said input contact is contacting said input terminal and said output contact is contacting said output terminal;
d) a magnetic response measuring means located within said housing for measuring said magnetic field and for calculating from the measurement of said magnetic field said dose;
and
e) a recording means connected to said magnetic response measuring means for recording said dose.

9 more elements

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, said plunger comprising a magnetically responsive element selected from the group consisting of diamagnetic materials and paramagnetic materials;
c) an inductive element coupled to said barrel such that the inductance of said inductive element varies in dependence upon the position of said plunger in said barrel, said inductive element having a first terminal and a second terminal;
d) an input terminal located on the outside of said syringe and electrically connected to said first terminal;
e) an output terminal located on the outside of said syringe and electrically connected to said second terminal;
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 causing an electric current to flow through said inductive element when said input contact is contacting said input terminal and said output contact is contacting said output terminal;
d) an inductance measuring means located within said housing for measuring the inductance of said inductive element and for calculating from the inductance said dose;
and
e) a recording means connected to said inductance measuring means for recording said dose.

9 more elements

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, said plunger comprising a magnetically responsive element selected from the group consisting of diamagnetic materials and paramagnetic materials;
said apparatus comprising:
a) a housing having a receptacle for receiving said syringe;
b) an inductive element for generating a magnetic field, said inductive element having a first terminal and a second terminal, and said inductive element being positioned coaxially to said receptacle such that when said syringe is placed in said receptacle, the intensity of said magnetic field varies in dependence upon the position of said plunger in said barrel;
c) a voltage generating means for producing a voltage difference across said first terminal and said second terminal, thereby causing an electric current to flow through said inductive element;
d) a magnetic response measuring means for measuring said magnetic field and for calculating from the measurement of said magnetic field said dose;
and
e) a recording means connected to said magnetic response measuring means for recording said dose.

6 more elements

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, said plunger comprising a magnetically responsive element selected from the group consisting of diamagnetic materials and paramagnetic materials;
said apparatus comprising:
a) a housing having a receptacle for receiving said syringe;
b) an inductive element having a first terminal and a second terminal, said inductive element being positioned coaxially to said receptacle such that when said syringe is placed in said receptacle, the inductance of said inductive element varies in dependence upon the position of said plunger in said barrel;
c) a voltage generating means for producing a voltage difference across said first terminal and said second terminal, thereby causing an electric current to flow through said inductive element;
d) an inductance measuring means for measuring the inductance of said inductive element and for calculating from the inductance said dose;
and
e) a recording means connected to said magnetic response measuring means for recording said dose.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/681,290Filed 22 Jul 1996 · continuation in part
Priority: 22 Jul 1994
Granted: 21 Jul 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification22 codes

A61M 5/1782
Syringes: devices aiding filling of syringes in situ
A61M 5/00
Devices for bringing media into the body in a subcutaneous, intra-vascular or
A61M 5/1684
Monitoring, detecting, signalling or eliminating infusion flow anomalies: by detecting the amount of infusate remaining, e.g. signalling end of…
A61M 5/1685
By detecting the amount of infusate remaining, e.g. signalling end of infusion: by detection of position of a floating member