Abstract: A liquid dosing arrangement has a liquid supply system with a first pressure sensor for measuring a first pressure p1; a liquid delivery system, with a second pressure sensor for measuring a second pressure p2; and an injection valve, which is arranged so that the liquid is supplied through a restricting member in the injection valve and let through the restricting member by a pulsed opening and closing valve mechanism. The pressure drop, and the dimensions of the restricting member in the injection valve, are selected to make the velocity ? of the liquid flowing through the restricting member is high enough to make the flow of liquid through the liquid delivery system independent of the viscosity of the liquid.

Abstract: An electromagnetic holding brake comprising a switchable electromagnet (4) for holding a movable sheet (6) in a predetermined position, wherein said brake further comprises a second fixated sheet (5) which is arranged substantially parallel to the movable sheet (6), such that said movable sheet (6) is clamped between the electromagnet (4) and the second sheet (5) when the current is switched on.

Abstract: An electrodynamic actuator has a permanently magnetic stationary part that forms an air-core with a magnetic field, and an armature with a coil arranged in the air-core. The armature moves in the magnetic field in the air-core dependent on a drive current fed to the coil. An increased accuracy is achieved by the provision of damping in relation to the speed of the armature, by arranging a sensing winding on the armature and connecting a calculation unit to the sensing winding. The calculation unit determines the speed of the armature from an induced voltage in the sensing winding caused by a movement of the armature in the magnetic field.

Abstract: An electromagnetic brake assembly has a brake shoe) movable between a first position at which it is located in a braking engagement with a movable surface and a second position at which it is located out of braking engagement with the movable surface. An electromagnet is energizable to bias the shoe to one or other of the first and the second positions and a power supply is provided having a direct current source for supplying a direct current flow to energize the electromagnet. The power supply further has an alternating current source that provides an alternating current flow through the electromagnet with a successively decreasing amplitude characteristic, after interruption of the direct current flow.

Abstract: A valve in a breathing device has a housing with an inlet and an outlet, a valve housing having an inlet and an outlet, a valve seat arranged in the housing, a valve body arranged in the housing to be freely moveable with respect to the valve seat between a closed position where the valve body completely covers the valve seat and an open position where the valve body is distanced from the valve seat. The valve body comprising a rigid central portion and a circumferential wrinkled and flexible portion devised for friction-free movement of the rigid central portion, and an actuator for controlling a force applied on the valve body in response to a control signal. The actuator includes an actuator body, a shaft having an end contactable with the valve body, and an electromagnetic displacement coil.

Abstract: An electromagnetic holding brake comprising a switchable electromagnet (4) for holding a movable sheet (6) in a predetermined position, wherein said brake further comprises a second fixated sheet (5) which is arranged substantially parallel to the movable sheet (6), such that said movable sheet (6) is clamped between the electromagnet (4) and the second sheet (5) when the current is switched on.

Abstract: An electrodynamic actuator has a permanently magnetic stationary part that forms an air-core with a magnetic field, and an armature with a coil arranged in the air-core. The armature moves in the magnetic field in the air-core dependent on a drive current fed to the coil. An increased accuracy is achieved by the provision of damping in relation to the speed of the armature, by arranging a sensing winding on the armature and connecting a calculation unit to the sensing winding. The calculation unit determines the speed of the armature from an induced voltage in the sensing winding caused by a movement of the armature in the magnetic field.

Abstract: An electromagnetic brake assembly has a brake shoe) movable between a first position at which it is located in a braking engagement with a movable surface and a second position at which it is located out of braking engagement with the movable surface. An electromagnet is energizable to bias the shoe to one or other of the first and the second positions and a power supply is provided having a direct current source for supplying a direct current flow to energize the electromagnet. The power supply further has an alternating current source that provides an alternating current flow through the electromagnet with a successively decreasing amplitude characteristic, after interruption of the direct current flow.

Abstract: A valve in a breathing device has a housing with an inlet and an outlet, a valve housing having an inlet and an outlet, a valve seat arranged in the housing, a valve body arranged in the housing to be freely moveable with respect to the valve seat between a closed position where the valve body completely covers the valve seat and an open position where the valve body is distanced from the valve seat. The valve body comprising a rigid central portion and a circumferential wrinkled and flexible portion devised for friction-free movement of the rigid central portion, and an actuator for controlling a force applied on the valve body in response to a control signal. The actuator includes an actuator body, a shaft having an end contactable with the valve body, and an electromagnetic displacement coil.

Abstract: A device for repeated registration of the number of thermal cycles to which a part for medical usage has been subjected has a temperature-sensitive element and/or a pressure-sensitive element arranged in conjunction with the part. This element reversibly changes its physical shape with temperature and/or pressure, variations in pressure being invariably associated with changes in temperature. A registration unit registers this change in shape when it exceeds a specific threshold value, as an indication of the part undergoing, or having undergone, a thermal cycle.

Abstract: In a method for locating a measurement and/or treatment catheter in a vessel or organ of a patient relative a fixed catheter, also positioned within the patient in the vicinity of the measurement and/or treatment catheter signals are transmitted from one of the catheters and received at the other one. The position and direction of the measurement and/or treatment catheter relative to the fixed catheter is then determined from the received signals. An arrangement for locating a measurement and/or treatment catheter, intended to be positioned in a vessel or organ of a patient, also includes a fixed catheter, also intended to be positioned within the patient in the vicinity of the measurement and/or treatment catheters. One of the catheters has a signal transmitter and the other one has a signal receiver for receiving signals from the signal transmitter. A signal processor determines from the received signals the position of the measurement and/or treatment catheter relative to the fixed catheter.

Abstract: A catheter arrangement has an active catheter, positionable in a vessel or organ of an animal, having at least one transducer disposed proximal the catheter tip; and a fixed catheter, also positionable within the animal in the vicinity of the active catheter, carrying a number of reference transducers. A signal processing unit is arranged to selectively operate the transducers to send and receive signals between the active and fixed catheters. The signal processing unit operates to calculate from the received signals at least two independent locations of the active catheter relative to the fixed catheter and to combine the independently calculated locations to provide a weighted average determination of the location in which the relative contributions of the calculated locations to the determined location decrease as their associated error values increase.

Abstract: In a method and apparatus for determining the position of a catheter inside the body of a patient, position signals are transmitted between the catheter and a position location unit, located at a distance from the catheter, the position signals are transmitted during a calibration stage from known calibration positions inside the body, or position signals, transmitted by the position location unit, are received at the known calibration positions. A correction function is determined from the difference between the calibration positions derived from the received location signals and the known, true calibration positions, whereupon catheter positions, derived from received position signals, are corrected in subsequent measurement stages according to the correction function.

Abstract: A flow regulator, suitable for use in a respirator/ventilator, has a conduit through which a medium flows whose flow is to be regulated and a choke valve arranged outside the conduit. The choke valve includes a first solenoid, a pressure actuator that is moved by the shaft end of the first solenoid, and a fixed element with the conduit disposed between the pressure actuator and the fixed element. Actuation of the first solenoid displaces the pressure actuator so as to alter the cross-section of the conduit. The shaft of the first solenoid exhibits an effective stroke length so that the pressure actuator, in a first limit position, leaves the flow cross-section of the conduit unaltered and, in a second limit position, partially compresses the conduit against the detent. The flow regulator is made lightweight and inexpensive and also has a comparatively low power consumption by using a second solenoid having a shaft which exhibits a short effective stroke length compared to the shaft of the first solenoid.

Abstract: A device for locating a port, facing the exterior of a patient, on a medical implant has at least one magnet and a detector arranged to sense magnetic fields. The magnet is associated with the implanted port and the detector is arranged to sense the magnetic field from the outside of the patient's body and, on the basis thereof, determine the location of the port. Alternatively, the detector is associated with the (implanted) port and the magnet is intended to be moved across the area above the detector on the exterior of the patient's body to then determine the location of the port from the magnetic field detected. The device can alternatively use a coil which is associated with the (implanted) port and a ferromagnetic element is moved on the exterior of the patient's body over the area above the coil. Changes in the inductance of the coil when the ferromagnetic means is moved are monitored and, therefrom, the position of the port is identified.

Abstract: An implantable infusion system has a neutral pressure medication supply container for liquid medication to be delivered to the patient, the supply container being devised so that its volume changes according to the amount of medication it contains, and a pump for pumping medication from the supply container, via a catheter, to the patient's body. The supply container and the pump are arranged inside an enclosure to which the catheter is connectable at the output of the pump. A closed space, at least partly contained inside the enclosure, in which the supply container is arranged, and in which essentially atmospheric pressure prevails, is arranged to change its volume to a corresponding degree when the volume of the supply container changes, so that the pressure is kept essentially unchanged.

Abstract: In a method for internally cleaning an implanted infusion system, having an infusion pump connected on its outlet side to a catheter via a nonreturn valve and a flushing port downstream of the nonreturn valve and upstream of the catheter, a first flow of cleaning fluid is passed through the infusion pump and the nonreturn valve. A second flow of secondary fluid is supplied through the flushing port, and a third fluid flow is discharged through the flushing port. A device for such cleaning has a pump such as a syringe connected to the flushing port for supplying the second flow of secondary fluid, for diluting or otherwise modifying the cleaning fluid passing through the infusion pump and the nonreturn check valve, and for discharging the third flow.

Abstract: In a method for measuring the flow resistance of a catheter in an implanted medication infusion system, the system having a medication reservoir and a pump that conveys the medication from the reservoir into the patient through a catheter connected to the discharge of the pump via a one-way valve, and having a rinsing input for direct access to the catheter disposed upstream of the catheter and downstream of the pump, the time required in order to pump a pre-determined liquid volume through the catheter via the rinsing input at a predetermined pressure is measured. In a device for such a flow check, a testing device is provided for connection to the rinsing input, which pumps a predetermined liquid volume through the catheter via the rinsing input at a predetermined pressure. Measuring sensors are provided for supplying signals from which the time required for pumping this liquid volume can be determined.

Abstract: Known implanted medication infusion systems have a medication container and a pump for pumping medication from the medication container into the patient via a catheter connected to the output of the pump. A flushing port is arranged downstream of the pump and upstream of the catheter. In a method for cleaning the catheter, a cleaning fluid is flushed through the flushing port and into the catheter. The orifice of the catheter is, during cleaning, placed in communication with the exterior of patient, and is isolated from the interior of the patient in order to convey the cleaning fluid out of the patient.

Abstract: In a device for conveying liquids having an intermittently energized pump and a filter for retaining air bubbles preceding the input side of the pump, the filter contains an admission opening in the form of a long gap and the gap volume is greater than the conveying volume of the pump given a single pump action. Even an air bubble that nearly completely covers the gap cannot be conveyed therethrough as long as the gap is in contact with the liquid to be pumped at some location.