Fluid pump
First Claim
1. A fluid pump device for use in conjunction with a chamber having a contained volume which can be reduced elastically and which incorporates or is locatable in circuit with spaced-apart unidirectional valves through which fluid can be passed with cyclic compression and expansion of the chamber;
- said pump device comprising;
a pair of spaced-apart clamp elements between which the pumping chamber is located in use of the device,electrically energisable means operable when energized to move one of the clamp elements relative to the other in an opening direction to permit expansion of the chamber,biasing means for exerting a closing force on the clamp elements whereby the chamber is biased to a compressed condition following de-energisation of the electrically energisable means,timing means for detecting the time duration T incurred in compressing the chamber to a predetermined extent against back pressure exerted by fluid within the chamber,fault indicating means for providing a fault condition indication if during operation of the device the time duration T incurred in compressing the chamber is less than a first predetermined time period T1 as a result of an excessively low back pressure being present in the chamber or is greater than second predetermined time period T2 as a result of an excessively high back pressure existing in the chamber, andelectrically actuatable adjusting means for adjusting the force exerted by the biasing means so that, when the device is subjected to normal no-fault operating conditions, the terminal end of the time duration T is located within a time slot bounded by the predetermined time periods T1 >
T and T2 <
T.
1 Assignment
0 Petitions
Accused Products
Abstract
A medical infusion pump for use in conjunction with a valved elastomeric pumping chamber. The pump comprises a pair of clamp elements between which the pumping chamber is located and one of the clamp elements is movable relative to the other to effect cyclic compression and expansion of the pumping chamber. The movable clamp element is constituted by an extension of a solenoid armature and such clamp element moves in a direction away from the fixed clamp element, to permit expansion of the pumping chamber, when the solenoid is energized. A compression spring acts against the solenoid armature and serves to bias the movable clamp element in a closing direction when the solenoid is de-energized, whereby a compressive force is applied to the pumping chamber. An electric motor is coupled to the spring by way of a motion translating mechanism and, when energized, the motor functions to change the effective length of the spring and, hence, the biasing force exerted on the movable clamp element.
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Citations
11 Claims
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1. A fluid pump device for use in conjunction with a chamber having a contained volume which can be reduced elastically and which incorporates or is locatable in circuit with spaced-apart unidirectional valves through which fluid can be passed with cyclic compression and expansion of the chamber;
- said pump device comprising;
a pair of spaced-apart clamp elements between which the pumping chamber is located in use of the device, electrically energisable means operable when energized to move one of the clamp elements relative to the other in an opening direction to permit expansion of the chamber, biasing means for exerting a closing force on the clamp elements whereby the chamber is biased to a compressed condition following de-energisation of the electrically energisable means, timing means for detecting the time duration T incurred in compressing the chamber to a predetermined extent against back pressure exerted by fluid within the chamber, fault indicating means for providing a fault condition indication if during operation of the device the time duration T incurred in compressing the chamber is less than a first predetermined time period T1 as a result of an excessively low back pressure being present in the chamber or is greater than second predetermined time period T2 as a result of an excessively high back pressure existing in the chamber, and electrically actuatable adjusting means for adjusting the force exerted by the biasing means so that, when the device is subjected to normal no-fault operating conditions, the terminal end of the time duration T is located within a time slot bounded by the predetermined time periods T1 >
T and T2 <
T. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
- said pump device comprising;
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2. A fluid pump device for use in conjunction with a chamber having a contained volume which can be reduced elastically and which incorporates or is locatable in circuit with spaced-apart unidirectional valves through which fluid can be passed with cyclic compression and expansion of the chamber;
- the pump device comprising;
a pair of spaced-apart clamp elements between which the pumping chamber is located in use of the device; electrically energizable means operable when energized to move one of the clamp elements relative to the other in an opening direction to permit expansion of the chamber, biasing means for exerting a closing force on the clamp elements whereby the chamber is biased to a compressed condition following de-energization of the electrically energizable means, timing means for detecting the time duration T incurred in compressing the chamber to a predetermined extent against back pressure exerted by fluid within the chamber, fault indicating means for providing a fault condition indication if, during operation of the device, the time duration T incurred in compressing the chamber varies at a rate greater than a predetermined rate over successive operating cycles of the pump device as a result of an excessively low or an excessively high back pressure being present in the chamber, and electrically actuatable adjusting means for adjusting the force exerted by the biasing means so that, when the device is subject to normal, no fault, operating conditions, the terminal end of the time duration T is located within a time slot bounded by first and second predetermined time period T1 >
T and T2 <
T respectively, where the time period T1 is the time within which the chamber will be biased to a compressed condition if an excessively low back pressure exists within the chamber and the time period T2 is the minimum time that will be occupied in biasing the chamber to a compressed condition if an excessively high back pressure exists within the chamber.
- the pump device comprising;
Specification