Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Rotary blood pump

In this centrifugal blood pump apparatus, one permanent magnet is provided in one surface of an impeller, a second permanent magnet is provided in an inner wall of a blood chamber, a third permanent magnet is provided in the other surface of the impeller, and a fourth permanent magnet and a rotor for driving the impeller to rotate are provided, with an diaphragm being interposed. An amount of change in attractive force between the first permanent magnet and the second permanent magnet and an amount of change in attractive force between the third and fourth permanent magnets when the impeller is eccentric are made substantially equal to each other. Therefore, a levitation position of the impeller can always be maintained at a substantially central position in a housing.

Centrifugal pump apparatus

In order to produce a pulsatile blood flow pattern that includes time periods of relatively high blood flow rates and time periods of relatively low blood flow rates, the operating speed of a blood pump can be selectively controlled to produce an operating speed pattern that includes time periods of relatively high rotation speeds and periods of relatively low rotation speeds For example, the blood pump is rotated at a first speed for a first period of time The speed of the blood pump is then decreased from the first speed to a second speed and is operated at the second speed for a second amount of time The speed of the blood pump is then decreased to a third speed for a third amount of time If desired, the operating speed pattern can be repeated to continue the pulsatile blood flow pattern

Generating artificial pulse

Materials and methods related to blood pump systems are described. These can be used in patients to, for example, monitor arterial pressure, measure blood flow, maintain left ventricular pressure within a particular range, avoid left ventricular collapse, prevent fusion of the aortic valve in a subject having a blood pump, and provide a means to wean a patient from a blood pump.

Blood flow meter

A method of estimating the blood flow rate of a heart ventricle assist device which is positioned externally of, or implanted in, a patient. The assist device comprises a blood pump having a rapidly rotating, electrically powered impeller, and comprises briefly interrupting power to the impeller to cause its rotation to slow. From this, blood viscosity can be estimated, which viscosity is used to obtain real time, estimated blood flow rates and pressure heads. Apparatus for accomplishing this is disclosed.

Sensorless flow estimation for implanted ventricle assist device

A centrifugal fluid pump assembly 1 includes a body section 5 and a control mechanism 6. The body section 5 includes a housing 20, an impeller 21 rotatable within the housing 20, and a motor 34 for rotating the impeller 21. The pump assembly 1 includes a motor current flow rate-related data storage section 60 for storing, for a plurality of different predetermined viscosities, predetermined viscosity-related flow rate data formed from a plurality of motor current flow rate relation data at a plurality of different impeller rotational speeds at predetermined fluid viscosity, a fluid measurement data inputting section 57, an impeller rotational speed measurement function, a motor current measurement function, and a flow rate calculating section 58 for using a fluid viscosity value, an impeller rotational speed value, a measured motor current and data stored in the motor current flow rate-related data storage section 60 to calculate a fluid flow rate.

Centrifugal fluid pump assembly

A centrifugal fluid pump assembly includes a body section and a control mechanism 6. The body section includes a housing, an impeller rotatable within the housing, and a motor for rotating the impeller. The pump assembly includes a motor current flow rate-related data storage section for storing, for a plurality of different predetermined viscosities, predetermined viscosity-related flow rate data formed from a plurality of motor current flow rate relation data at a plurality of different impeller rotational speeds at predetermined fluid viscosity, a fluid measurement data inputting section, an impeller rotational speed measurement function, a motor current measurement function, and a flow rate calculating section 58 for using a fluid viscosity value, an impeller rotational speed value, a measured motor current and data stored in the motor current flow rate-related data storage section to calculate a fluid flow rate.

Centrifugal fluid pump assembly with flow rate calculating section

PROBLEM TO BE SOLVED: To provide a centrifugal liquid-pumping system being equipped with a flow rate-calculating function which can easily and surely calculate a liquid flow rate (discharging amount) without using a flow meter SOLUTION: This centrifugal liquid-pumping system 1 is equipped with a main body section 5 and a control mechanism 6 The main body section 5 is equipped with a housing 20, an impeller 21 which rotates in the housing, and a motor 34 to rotate the impeller 21 The pumping system 1 is also equipped with a motor current/discharge rate-related data storage unit 60, a liquid measurement data input unit 57, and a discharging flow rate computing unit 58 In this case, the motor current/discharge rate-related data storage unit 60 stores specified viscosity-related discharging flow rate data comprising a plurality of motor current/discharge rate-related data for a plurality of impeller rotating numbers at specified liquid viscosities, for a plurality of specified viscosities being different The discharging flow rate computing unit 58 computes a liquid- discharge rate using an impeller rotating number-measuring function, a motor current value-measuring function, a liquid viscosity value, an impeller rotating number value, a motor current measured value, and the data stored in the motor current/discharge rate-related data storage unit COPYRIGHT: (C)2003,JPO

Masamichi Yanai

Papers

Centrifugal fluid pump assembly

Centrifugal fluid pump assembly with flow rate calculating section

Centrifugal liquid-pumping system