JPH0441867Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention is a pulsatile flow generator for testing artificial organs used for testing or researching the durability of artificial organs of the circulatory system used in the human body. Regarding.

[Conventional technology]

A fluid flow that periodically generates predetermined pressure fluctuations within a certain pressure range is called a pulsatile flow. For example, the flow in the circulatory system in which blood in the human body flows from the heart to various parts of the human body and returns to the heart is a pulsatile flow. Pulsatile flow allows better maintenance of organ circulation and peripheral circulation than non-pulsatile flow, and is therefore said to be advantageous in terms of cardiac function.

Conventionally, in the field of medical device technology, several pulsatile flow generators have been proposed to restore heart function for a short period of time due to the need to pump blood to various parts of the human body during heart surgery. A pulsatile flow generator is one such device. Figure 5 is a schematic diagram of a roller pump, and the principle is as shown in this diagram, the roller R and pump chamber W are brought into contact with each other halfway through their rotation, and the pump chamber W is squeezed while rotating the roller R. It is. For example, the pulsatile flow generator proposed in Medical Science [VoL.56, No. 5 (1986)] connects such a roller pump to a voltage control device and an arithmetic circuit, and the roller This device generates a pulsating flow by rapidly increasing the rotational speed within a certain angle range once or twice in between. According to the above research paper, it has been confirmed that this device can relatively easily generate good pulsatile flow.

[Problem that the invention attempts to solve]

Although the pulsatile flow generating device using the roller pump described above is capable of generating pulsatile flow, it is not possible to generate pulsatile flow due to actual physiological phenomena of the human body, such as blood vessels in myocardial restriction state, high blood pressure state, and pulsatile flow state of high pressure and low pressure. Reproducing fluctuations, etc. cannot be done without complex control. Artificial organs are currently in the development stage, and the pulsatile flow generator described above is only used for a short time when the human body needs it, such as during surgery.
Therefore, the durability of the artificial organ itself was not so much of an issue, but the short-term performance of static strength such as pressure resistance was the issue. However, once the performance of artificial organs has been perfected, the next issue becomes durability over long-term use.

For such durability, the materials used, strength design, etc. are important factors, but fatigue strength is the most important issue. Although various strength tests and fatigue tests for the material itself have been devised and can be used, no method has yet been developed for performing strength tests and fatigue tests on artificial organs that take into account the stress generated by internal pressure. Therefore, durability testing of artificial organs under conditions equivalent to or similar to physiological phenomena in the human body, especially conditions including pulsatile flow, will become an issue in the future.

[Purpose of invention]

This idea was devised in view of the above-mentioned problems, and its purpose is to develop a testing machine that can perform fatigue tests under the same conditions as when an artificial organ is attached to the human body, especially a test machine that is identical to the human body or Assuming a similar circulatory system mechanism, pulsatile flow can be generated close to actual conditions, including reproduction of pathological phenomena, and
It is an object of the present invention to provide a pulsatile flow generating device for artificial organ testing that can intentionally and easily change pressure fluctuations of pulsatile flow.

[Means for solving problems]

The pulsatile flow generating device for artificial organ testing of this invention includes:
In order to achieve the above objective, the liquid contained in the tank is pumped by a plunger pump driven by a cam mechanism with replaceable cams, and the liquid discharged from the plunger pump is delivered to the artificial organ through the accumulator. At the same time, the present invention is characterized in that a flow passage cross-sectional area adjusting valve is provided in the return pipe that leads the liquid exiting the artificial organ to the tank.

[Effect]

When the plunger pump is driven by a cam mechanism that is a driving device, the discharged liquid is sent out to the artificial organ through the accumulator while fluctuating in a constant pressure range. This sudden pressure rise due to discharge from the plunger pump is absorbed by the accumulator. The varying pressure range is determined by the spring load of the accumulator. Further, the standard setting of pressure fluctuations in the pipe line is carried out by adjusting the flow passage cross-sectional area control valve. That is, when the control valve is throttled, the pressure in the pipe line increases, and this state is maintained by the accumulator.

The period of pressure fluctuation can be changed by changing the rotation speed of the motor that drives the plunger pump.

The cam mechanism of the drive device generates reciprocating motion in the plunger rod according to the shape of the cam by rotating the cam. Such reciprocating motion is directly transmitted to the plunger pump and changes the discharge amount over time. Moreover, the pressure in the pipe line also changes in response to the change in the discharge amount over time. The cam of this cam mechanism can be replaced with a cam having a cam shape that produces the pressure fluctuations that are previously intended to be tested.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an overall schematic diagram of the apparatus according to the present invention. 1 is a liquid tank, 3 is a plunger pump,
5 is an accumulator, 7 is an artificial organ, and 9 is a valve, which are connected by a pipe 10 to constitute one circulation circuit.

The liquid 2 in the tank 1 corresponds to blood, and this tank 1 corresponds to the atrium.

The plunger pump 3 is a mechanism for feeding the liquid 2, and has a cam 14 directly connected to the motor 11.
It is designed to be driven in a reciprocating manner to move the plunger rod 4 up and down. Further, this plunger pump 3 is provided with valves 6 and 8 at the inlet and outlet of the chamber so that fluid flows only in one direction as shown in the figure. That is, this plunger pump 3 corresponds to the heart in the human body.

The accumulator 5 has a spring 19 connected to one end of a screw 20 for adjusting the load, and this screw 20 is screwed into and supported by a bracket 21. This accumulator 5 corresponds to the elasticity of blood vessels in the human body.

7 is an artificial organ for durability testing, and a pressure gauge 30 is installed at the liquid inlet to measure the liquid pressure P.

The valve 9 serves as an orifice provided in the conduit to expand, reduce, or adjust the cross-sectional area of the flow path through which the liquid 2 flows, and has the effect of imparting resistance to the conduit. That is, this valve 9 is for reproducing the high and low blood pressure states in the peripheral blood vessels of the human body.

In the circulation circuit configured as above, when the motor 11 is operated to drive the cam mechanism, the cam 1
4 moves the plunger rod 4 of the plunger pump 3 up and down via the connecting rod 17 and lever 15 to discharge the liquid 2. As described above, the plunger pump 3 discharges the liquid 2 from the tank 1 only in one direction of the accumulator 5, and does not allow it to flow back.

Then, the plunger rod 4 is caused to generate reciprocating motion according to the shape of the cam 14. This reciprocating movement causes the discharge amount to change over time, and the pressure in the pipe line also changes in response to the change in the discharge amount over time. Therefore, if the shape of the cam 14 is set in advance to a shape that produces an intended pressure variation, it is possible to replace and use a cam that produces any pressure variation depending on the purpose of the test.

The liquid 2 enters an accumulator 5 provided in the middle of the pipe line 10. This accumulator 5 has the role of absorbing the sudden pressure rise due to discharge from the plunger pump, and also maintains the pressure in the pipeline to a certain level when the flow cross section of the liquid 2 in the orifice of the valve 9 is expanded or contracted. It serves to maintain the

The liquid 2 then enters the artificial organ 7 from the accumulator 5, exits the artificial organ 7, passes through the valve 9, and enters the tank 1. Here, when the valve 9 is throttled to reduce the cross-sectional area of the flow path, the pressure in the pipe line 10 increases, and the accumulator 5 maintains the standard setting for pressure fluctuations at a high level.

Next, changes in the pressure P of the conduit displayed on the pressure gauge at the entrance of the artificial organ will be explained.

Taking as an example a cam having the shape shown in FIG. 5, FIG. 2 shows a pressure gauge 30 installed at the entrance of the artificial organ 7.
It shows the change in pressure P of . The amplitude L of this pressure P is determined by the spring load of the spring 19 of the accumulator 5. The load applied to spring 19 is screw 2
0, and the amplitude L can be changed by adjusting this screw 20. The period of pressure fluctuation is determined by the rotation speed of the motor 11.

FIG. 3 shows the state of pressure fluctuation when the rotational speed of the motor 11 is increased or decreased in the state shown in FIG. 2. By changing the rotation speed of the motor 11 in this manner, the cycle H of pressure change, that is, the frequency, can be changed.

FIG. 4 shows the movement of the reference position for pressure fluctuations. That is, when the cross-sectional area of the flow path is narrowed by the valve 9, this reference position moves upward by Z, and when it is expanded, it is located at the bottom.

Basically, the pressure at the inlet of the artificial organ fluctuates as described above, but the liquid driven by the cam mechanism and discharged from the plunger pump 3 reaches the plunger pump 3 before the pressure in the accumulator 5 returns to its original value. The next discharge is performed at , and the intended pulsatile flow is obtained. In addition, in Fig. 1, the accumulator 5
may be placed between the artificial organ 7 and the valve 9.

Furthermore, if it is intended to cause different pressure fluctuations in the conduit 10, it is sufficient to replace and use a different cam for that purpose.

〔Effect of the invention〕

As described in detail above, the pulsatile flow generator for artificial organ testing of the present invention uses a plunger pump driven by a cam mechanism to pump the liquid contained in the tank, and the liquid pumped by the plunger pump is supplied to the artificial organ via an accumulator, and a flow passage cross-sectional area adjustment valve is provided in the retan conduit that returns the liquid exiting the artificial organ to the tank. Since the plunger pump corresponds to the heart, the accumulator corresponds to the elasticity of blood vessels, and the flow path cross-sectional area control valve corresponds to blood pressure, a pulsatile flow can be obtained with a system similar in structure and function to the human body. Furthermore, since the plunger pump is driven by a cam mechanism, the shape of the cam can freely generate a pulsating flow that changes minutely and intricately within one cycle, just like the pressure changes from the actual heart. As described above, with this invention, it is possible to manufacture a pulsating flow generating device that generates complicated pressure changes with a simple mechanism and at low cost. A cam is the most stable and reliable mechanism for repeating complex pressure fluctuations in one cycle. In addition, necessary pattern changes can be easily made by replacing the cam.

[Brief explanation of the drawing]

FIG. 1 shows an overall schematic diagram of the pulsatile flow generator according to this invention. Fig. 2 shows changes in the pressure P of the pressure gauge 30 installed at the entrance of the artificial organ 7, and Fig. 3 shows the state of pressure fluctuation when the rotation speed of the motor 11 is increased or decreased in the state shown in Fig. 2. shows. Fourth
The figure shows the movement of the reference position of pressure fluctuations. FIG. 5 shows an example of a cam having a specific shape, and FIG. 6 shows a principle diagram of a roller pump. 1...Liquid tank, 3...Plunger pump, 4...Plunger rod, 5...Accumulator, 6, 8...Valve, 9...Valve, 10...Pipe line, 11...Motor, 13...Crank , 14...
... Drive cam, 15 ... Lever for driving plunger pump, 16 ... Lever rotation fulcrum for driving plunger pump, 19 ... Spring for accumulator, 20
...Adjustment screw, 21...Mounting bracket for adjustment screw, 30...Pressure gauge.

Claims (1)

[Scope of utility model registration request] A circulation pipe is formed from a tank containing liquid to the tank via the artificial organ, and a plunger pump for liquid feeding driven by a cam mechanism and an accumulator are sequentially connected to the pipe from the former tank to the artificial organ. A pulsating flow generation device for artificial organ testing, characterized in that a flow passage cross-sectional area adjustment valve is disposed in a conduit extending from the artificial organ to the tank.