Magnetic suspension pump with symmetrical hollow thin-wall configuration and control method thereofTechnical Field
The invention relates to the technical field of biomedicine, in particular to a magnetic suspension pump with a symmetrical hollow thin-wall configuration and a control method thereof.
Background
Ventricular assist devices (VentricularAssist Device, VAD) play a critical role in the treatment of cardiac diseases. The haemolytic performance of a VAD device is a critical factor that must be appreciated during its design and use. Haemolysis, i.e. the rupture of erythrocytes to release hemoglobin, not only leads to anemia, but may also lead to renal failure and other complications. Therefore, reducing the rate of hemolysis is critical to improving the safety and effectiveness of VAD equipment.
Conventional mechanical axial flow pumps are prone to high shear forces and blood turbulence during operation due to the mechanical bearings and contact members in their design. These high shear forces and turbulence are one of the main causes of hemolysis. During the blood pumping process of the mechanical axial flow pump, blood cells are deformed and ruptured under high shear force, thereby causing hemolysis. Furthermore, wear and tear of the mechanical contact parts also increases the risk of haemolysis.
In contrast, the magnetic suspension centrifugal pump adopts a non-contact magnetic suspension technology, so that the existence of a mechanical bearing is eliminated, and the mechanical friction and contact wear are greatly reduced. However, although the magnetic levitation centrifugal pump has a remarkable advantage in terms of reducing mechanical wear, it generates a degree of turbulence and high shearing force at high rotation speed, thereby causing a problem of hemolysis.
Disclosure of Invention
This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be used to limit the scope of the application.
Therefore, the invention aims to provide a magnetic suspension pump with a symmetrical hollow thin-wall configuration and a control method thereof, and the optimized design of a flow channel structure and the combination of an advanced state space intelligent control technology can effectively reduce blood turbulence and shearing force, thereby remarkably reducing hemolysis and improving the safety and the effectiveness of VAD equipment.
In order to solve the technical problems, according to one aspect of the present invention, the following technical solutions are provided:
A magnetic suspension pump of symmetrical hollow thin-wall configuration, comprising:
the shell comprises an upper pump shell and a lower pump shell which is connected with the upper pump shell in a sealing way;
The magnetic suspension blades are arranged in the shell and are provided with symmetrical cavities, liquid inlet hollow channels are formed in the positions of the magnetic suspension blades between the cavities, and thin-wall channels communicated with the liquid inlet hollow channels are formed between the positions of the outer sides of the cavities and the inner wall of the lower pump shell;
And the magnetic suspension driving assembly is used for controlling and driving the magnetic suspension blades to rotate in the shell.
As a preferable scheme of the magnetic suspension pump with the symmetrical hollow thin-wall configuration, barb rings are arranged on the outer wall of the liquid inlet pipeline of the upper pump shell at equal intervals.
As a preferable scheme of the magnetic suspension pump with the symmetrical hollow thin-wall configuration, the outer wall of the lower pump shell is provided with a liquid outlet pipeline, and the inside of the liquid outlet pipeline is provided with an annular liquid outlet channel communicated with the thin-wall channel.
As a preferable scheme of the magnetic suspension pump with the symmetrical hollow thin-wall structure, the magnetic suspension blades, the upper pump shell and the lower pump shell surround to form a first slow flow cavity communicated with the liquid inlet hollow channel, and symmetrical second slow flow cavities are formed in positions, located on two sides of the liquid inlet hollow channel, of the inner walls of the magnetic suspension blades.
As a preferable scheme of the symmetrical hollow thin-wall magnetic suspension pump, the magnetic suspension driving assembly comprises a ring seat, radial stator magnetic suspension modules, axial stator magnetic suspension modules, radial rotor magnetic suspension modules, an axial rotor magnetic suspension module and a microcontroller, wherein the ring seat is coaxially arranged with a shell, the radial stator magnetic suspension modules are arranged on the side wall of the ring seat and are equidistantly arranged, the axial stator magnetic suspension modules are embedded at the bottom of the ring seat, the radial rotor magnetic suspension modules are arranged on the inner wall of a cavity at equal intervals, and the axial rotor magnetic suspension modules are arranged at the bottom of the cavity;
The microcontroller collects voltages of the radial rotor magnetic levitation module and the axial rotor magnetic levitation module and adjusts current values in the radial stator magnetic levitation module and the axial stator magnetic levitation module.
As a preferable scheme of the magnetic suspension pump with the symmetrical hollow thin-wall configuration, the upper pump shell and the lower pump shell are sealed by adopting an ultrasonic welding process.
As a preferable scheme of the magnetic suspension pump with the symmetrical hollow thin-wall configuration, the thickness of the thin-wall channel is smaller than that of the magnetic suspension pump.
As a preferable scheme of the symmetrical hollow thin-wall magnetic suspension pump, the radial stator magnetic suspension modules and the radial rotor magnetic suspension modules form a group of radial magnetic suspension modules, and the radial magnetic suspension modules are arranged in at least two groups.
As a preferable scheme of the symmetrical hollow thin-wall magnetic suspension pump, the radial rotor magnetic suspension module and the axial rotor magnetic suspension module comprise at least one Hall sensor and a communication module which are used for communicating and transmitting signals with a microcontroller, and a micro battery is arranged in the magnetic suspension pump for supplying power.
A control method of a magnetic suspension pump with a symmetrical hollow thin-wall structure is characterized by comprising the following specific steps:
S1, building a circulating blood path, and building a path for simulating blood from an inlet to an outlet of a magnetic suspension pump after pre-charging and exhausting;
s2, initializing a system, and ensuring that Hall sensors in the radial rotor magnetic levitation module and the axial rotor magnetic levitation module work normally without obvious zero drift and temperature drift;
s3, solving the relation between the current i (t) of the inner coil of the magnetic levitation motor and the rotating speed omega (t) of the inner rotor of the motor, wherein the relation is represented by kirchhoff voltage law, and the circuit equation of the coil of the magnetic levitation motor is as followsWherein R is the internal resistance of the motor, L is the inductance of the motor, ke is the back electromotive force coefficient, V is the voltage, and the above are constants;
s4, establishing a rotation dynamics model, wherein the rotation motion equation of the magnetic suspension blade is as follows according to Newton' S second lawWherein b is a damping coefficient, J is a moment of inertia, and kt is a torque coefficient;
S5, establishing currentAnd rotational speedThe differential equation relation of the constituted vector is used for designing and calculating the state equation of the microcontroller:
wherein the matrixAs distinguishable constants, matrixCan be treated as constant when the voltage is constant;
S6, the microcontroller collects voltage signals of the radial rotor magnetic levitation module and the axial rotor magnetic levitation module, adjusts current of the axial stator magnetic levitation module in real time according to a state equation of the microcontroller so that the magnetic levitation blades overcome self gravity to levitate, adjusts current values in the radial stator magnetic levitation module in real time, and applies rated torque to the magnetic levitation blades through changing magnetic field intensity and magnetic field direction to achieve high-speed rotation of the magnetic levitation blades;
s7, the magnetic suspension blade rotating at a high speed sucks simulated blood, and the blood flows out through the liquid outlet pipeline after flowing through the hollow channel and the thin-wall channel in the magnetic suspension blade.
Compared with the prior art, the invention has the beneficial effects that the magnetic suspension blade with the symmetrical hollow structure is designed to be used as the rotor by optimizing the flow channel design of the pump, the rotor of the blade and the lower pump shell form a thin-wall long and narrow passage, a dynamic differential equation model based on a state space is established, the radial and axial stator currents are controlled in real time by the microcontroller, the high-speed rotation and suspension of the rotor blade can be realized, the turbulent flow effect during the blood flowing can be greatly inhibited, the blood flowing is more stable and uniform, the vortex and local high-shear area is reduced, the fluid dynamics characteristic is improved, and the hemolysis is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following detailed description will be given with reference to the accompanying drawings and detailed embodiments, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive faculty for a person skilled in the art. Wherein:
FIG. 1 is a schematic illustration of the external structure of a magnetic suspension pump of the present invention in a symmetrical hollow thin-wall configuration;
FIG. 2 is a schematic diagram of the assembly structure of a ring seat, a radial stator magnetic levitation module and an axial stator magnetic levitation module of a magnetic levitation pump with a symmetrical hollow thin-wall configuration;
FIG. 3 is a cross-sectional view of a magnetic suspension pump of the present invention in a symmetrical hollow thin-wall configuration;
fig. 4 is a control schematic diagram of a magnetic suspension pump and microcontroller of a symmetrical hollow thin-wall configuration of the present invention.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings.
Next, the present invention will be described in detail with reference to the drawings, wherein the sectional view of the device structure is not partially enlarged to general scale for the convenience of description, and the drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
The invention provides a magnetic suspension pump with a symmetrical hollow thin-wall configuration and a control method thereof, which can effectively reduce blood turbulence and shearing force by optimally designing a flow channel structure and combining an advanced state space intelligent control technology, thereby remarkably reducing hemolysis and improving the safety and the effectiveness of VAD equipment.
Example 1
Fig. 1 to 3 are schematic structural views of an embodiment of a magnetic suspension pump with a symmetrical hollow thin-wall structure according to the present invention, referring to fig. 1 to 3, a main body portion of the magnetic suspension pump with a symmetrical hollow thin-wall structure includes a housing 100, a magnetic suspension blade 200 and a magnetic suspension driving assembly 300.
The casing 100 includes an upper casing 110 and a lower casing 120 sealingly connected to the upper casing 110, in this embodiment, the upper casing 110 and the lower casing 120 are sealed by an ultrasonic welding process, and preferably, barb rings 110a are disposed on the outer wall of the liquid inlet pipe of the upper casing 110 at equal intervals, so that the liquid inlet pipe of the upper casing 110 is more tightly connected to the connected pipe.
The magnetic levitation blades 200 are arranged in the housing 100, and have symmetrical cavities 210, and the magnetic levitation blades 200 are positioned between the cavities 210 and have liquid inlet hollow channels H, and the positions positioned outside the cavities 210 and the inner wall of the lower pump housing 120 form a thin-wall channel L communicated with the liquid inlet hollow channels H.
Wherein, a row of radial stator magnetic levitation modules 320 and a row of radial rotor magnetic levitation modules 340 form a group of radial magnetic levitation modules, and the radial magnetic levitation modules are arranged at least in two groups, the outer wall of the lower pump shell 120 is provided with a liquid outlet pipeline 120a, the inside of the liquid outlet pipeline is provided with an annular liquid outlet channel 120b communicated with the thin-wall channel L, the magnetic levitation blades 200, the upper pump shell 110 and the lower pump shell 120 surround to form a first slow flow cavity M communicated with the liquid inlet hollow channel H, and symmetrical second slow flow cavities N are formed in positions of the inner walls of the magnetic levitation blades 200 positioned at two sides of the liquid inlet hollow channel H for relieving turbulence of blood in the hollow channel H of the magnetic levitation blades 200, so that blood flow is more stable and uniform.
The magnetic levitation driving assembly 300 is used for controlling and driving the magnetic levitation blades 200 to rotate in the housing 100, in this embodiment, the magnetic levitation driving assembly 300 includes a ring seat 310 coaxially arranged with the housing 100, radial stator magnetic levitation modules 320 disposed on the side wall of the ring seat 310 and equidistantly arranged, an axial stator magnetic levitation module 330 embedded at the bottom of the ring seat 310, radial rotor magnetic levitation modules 340 disposed on the inner wall of the cavity 210 and equidistantly arranged, an axial rotor magnetic levitation module 350 disposed at the bottom of the cavity 210, and a microcontroller, wherein the microcontroller collects voltages of the radial rotor magnetic levitation modules 340 and the axial rotor magnetic levitation modules 350 and adjusts current values in the radial stator magnetic levitation modules 320 and the axial stator magnetic levitation modules 330, and preferably, the radial rotor magnetic levitation modules 340 and the axial rotor magnetic levitation modules 350 include at least one hall sensor and a communication module for communicating signals with the microcontroller and supplying power to the built-in micro battery.
Example 2
The invention also provides a control method of the magnetic suspension pump with the symmetrical hollow thin-wall structure, which can realize the high-speed rotation and suspension of the rotor blade by utilizing the microcontroller to control the radial and axial stator currents in real time, can greatly inhibit the turbulent flow effect when blood flows through, and ensures that the blood flow is more stable and uniform, and specifically, the control method of the magnetic suspension pump with the symmetrical hollow thin-wall structure comprises the following specific steps:
S1, building a circulating blood path, and building a path for simulating blood from an inlet to an outlet of a magnetic suspension pump after pre-charging and exhausting;
s2, initializing a system, and ensuring that Hall sensors in the radial rotor magnetic levitation module 340 and the axial rotor magnetic levitation module 350 work normally without obvious zero drift and temperature drift;
s3, solving the relation between the current i (t) of the inner coil of the magnetic levitation motor and the rotating speed omega (t) of the inner rotor of the motor, wherein the relation is represented by kirchhoff voltage law, and the circuit equation of the coil of the magnetic levitation motor is as followsWherein R is the internal resistance of the motor, L is the inductance of the motor, ke is the back electromotive force coefficient, V is the voltage, and the above are constants;
S4, establishing a rotation dynamics model, wherein the rotation motion equation of the magnetic suspension blade 200 is as follows according to Newton' S second lawWherein b is a damping coefficient, J is a moment of inertia, and kt is a torque coefficient;
S5, establishing currentAnd rotational speedThe differential equation relation of the constituted vector is used for designing and calculating the state equation of the microcontroller:
Wherein the matrixAs distinguishable constants, matrixCan be treated as constant when the voltage is constant;
S6, the microcontroller collects voltage signals of the radial rotor magnetic levitation module 340 and the axial rotor magnetic levitation module 350, adjusts current of the axial stator magnetic levitation module 330 in real time according to a state equation of the microcontroller so that the magnetic levitation blade 200 can overcome self gravity to levitate, adjusts current values in the radial stator magnetic levitation module 320 in real time, and applies rated torque to the magnetic levitation blade 200 by changing magnetic field intensity and magnetic field direction to realize high-speed rotation of the magnetic levitation blade 200;
S7, the magnetic suspension blade 200 rotating at a high speed sucks simulated blood, and the blood flows through the hollow channel H and the thin-wall channel L in the magnetic suspension blade 200 and then flows out through the liquid outlet pipeline 120 a.
Although the invention has been described hereinabove with reference to embodiments, various modifications thereof may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the features of the disclosed embodiments may be combined with each other in any manner as long as there is no structural conflict, and the exhaustive description of these combinations is not given in this specification merely for the sake of omitting the descriptions and saving resources. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.