Patent Application
20090097995
1. Technical Field
The present invention relates to a syringe pump for suction and exhaustion of a fixed quantity, and more particularly to a syringe pump, which is capable of taking in and out a fixed quantity of liquid or powder (hereinafter, collectively referred to as “fluid”) more precisely by moving a piston using a linear actuator.
Especially, the above syringe pump uses the linear actuator which applies linear motion of a piezoelectric motor in order to move the piston, such that suction and exhaustion of the fluid can be performed more precisely through controlling of power supply with respect to the piezoelectric linear motor.
2. Description of the Related Art
Generally, a fixed quantity feeder system is used to supply a precise quantity of chemical solution in a laboratory or medical substance as a medical instrument.
In such a fixed quantity feeder system, a stepping motor is generally used as a driving means for controlling the movement of a piston.
However, the conventional fixed quantity feeder system has such a complicated structure that manufacturing thereof is difficult. Furthermore, since the structure is hard to be in a compact size, handling of the system is inconvenient.
In addition, the stepping motor conventionally applied in the fixed quantity feeder system may sometimes cause vibration or resonance at certain frequency, thereby deteriorating the function of supplying a fixed quantity fluid.
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a syringe pump, capable of controlling movement of a piston more precisely.
Especially, it is another object of the present invention to provide a syringe pump, capable of controlling a moving distance of a piston more precisely by intermittently supplying power to a linear actuator that moves the piston, and accordingly precisely controlling quantity of fluid being taken in and out of a cylinder.
More preferably, it is yet another object of the present invention to provide a syringe pump, capable of reducing the whole size of the pump by using the piezoelectric linear motor as a linear actuator.
In accordance with an aspect of the present invention, there is provided a syringe pump comprising a cylinder which includes a receiving space, a piston which is mounted in the cylinder to pump liquid or powder in and out of the cylinder, and a piezoelectric linear actuator which moves the piston in a reciprocating manner.
In addition, the piezoelectric linear actuator may comprise a piezoelectric motor constituted by piezoelectric mediums.
The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings such that those who are skilled in the art can easily understand and implement the present invention.
As shown in the drawings, the syringe pump includes a linear actuator 3.
More specifically, the syringe pump according to the embodiment of the present invention comprises a cylinder 1 which includes a receiving space, a piston 2 which is mounted in the cylinder 1 to move liquid or powder in and out with respect to the cylinder 1, and a linear motor 3 which moves the piston 2 in a reciprocating motion.
In the above-structured syringe pump with the piezoelectric linear motor, the cylinder 1 and the piston 2 are used to take in certain liquid or micro powder and exhaust the liquid or powder to a desired place, having a similar structure with a syringe. The liquid and powder will be referred to as fluid.
That is, the cylinder 1 is formed as a tube holding a receiving space 1a for receiving the fluid. As shown in
The cylinder 1 further includes a needle connection part 11 having a small diameter at the inlet and outlet hole such that the fluid can be supplied to or taken in from a narrow space as desired. Additionally, a needle 4 is removably connected to the needle connection part 11.
As shown in
The above cylinder 1 and needle 4 are structured in substantially the same manner as those of a general syringe. Therefore, the structure of the present invention can be achieved by adding a piston which includes the linear actuator 3 to the general conventional syringe.
The linear actuator 3 constituting the syringe pump, as shown in the drawings, is preferably implemented by a piezoelectric linear motor in order to reciprocate the piston 2.
The piezoelectric linear motor is a sort of motor that applies the principle in that a piezoelectric element contracts and expands according to power supply. As shown in the drawings, the piezoelectric linear motor includes a plurality of legs extending and contracting in a certain direction like a motion of an inchworm in accordance with power supply, thereby moving by itself or moving other parts in a pushing manner. Since the piezoelectric linear motor is generally known and applied in the art, detailed description thereof will be omitted herein.
In the above structure, as shown in
In a case where the piston 2 is thus directly connected to the linear actuator 3, the piston 2 is moved as the linear actuator 3 moves along an inner wall of the cylinder 1.
In other words, the linear actuator 3 shown in
Another method for achieving connection between the piston 2 and the linear actuator 3 is illustrated in
As shown in the drawings, a rod 5 may be additionally mounted between the piston 2 and the linear actuator 3.
More specifically, as shown in
Furthermore, when the piston 2 is connected thus using the rod 5, the linear actuator 3 used in the embodiment of the present invention can also be easily adopted in existing syringe pumps.
As shown in the drawings, a connection protrusion 51 having a spherical shape is formed at an end of the rod 5, facing the piston 2 so as to connect the rod 5 with the piston 2. In addition, the piston 2 is formed with the connection recess 21 of a spherical shape for force-fit with the connection protrusion 51.
Thus, since connection parts of the rod 5 and the piston 2 are structured in the form of the spherical protrusion and the spherical recess, respectively, the piston 2 can be moved vertically in the cylinder 1 even when the rod 5 is inclined to a certain direction.
In addition, a sealant member 2a is mounted around the outer circumference of the piston 2 to prevent leakage of the fluid through a gap between the piston 2 and the cylinder 1.
In the above-structured syringe pump, the linear actuator 3 may have various modified configurations according to the present invention. Also, the embodiment is illustrated in the drawings only by way of example, but does not limit the present invention.
As can be appreciated from the above description, in accordance with a syringe pump according to the embodiment of the present invention, control of a moving distance of a piston can be performed more precisely by intermittently supplying power to a linear actuator. As a result, quantity of fluid taken in and out of a cylinder can be precisely controlled.
Especially, since the piezoelectric linear motor is used as a linear actuator for operating the piston, the syringe pump can be achieved in a compacter size.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2007-0103742 | Oct 2007 | KR | national |
