JPS6335835B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for a gas-driven pump such as a blood pump device.

BACKGROUND OF THE INVENTION Conventionally, as this type of device, one configured as shown in FIG. 1, for example, has been known. In the figure, reference numeral 1 is a compressor, 2 is a vacuum pump, 3 is a positive pressure tank, 4 is a negative pressure tank, 5 is a three-way electromagnetic switching valve, 6 is a pressure regulating valve, and 7 is a primary pressure tank.

A positive pressure tank 3 and a negative pressure tank 4 are maintained at a constant pressure by a pressure regulating valve 6 by operating a three-way electromagnetic switching valve 5.
Positive pressure and negative pressure are alternately applied to a gas-driven pump 8, such as a blood pump device, provided at the drive pressure outlet.

According to the above drive device, in order to supply constant pressure to the gas-driven pump 8 and operate it as rated,
It is necessary to set the tank capacities of the positive pressure tank 3 and the negative pressure tank 4 to be several tens of times (40 to 50 times) larger than the pump capacity of the gas-driven pump 8, for example.

The reason for this is as follows. That is, when the three-way electromagnetic switching valve 5 is switched, for example, when the positive pressure tank 3 is opened, the pressure inside the tank 3 is temporarily lowered, and when the negative pressure tank is opened, the pressure inside the tank 4 is decreased.
The pressure inside the tank will temporarily rise, but if the tank capacity is sufficiently large, these pressure drops and pressure rises will be negligible. However, when the tank capacity is insufficient, the rate of pressure drop and pressure rise is large. Since the pressure regulating valve 6 generally has a lower response speed than the three-way electromagnetic switching valve 5, it cannot immediately compensate for these pressure drops and pressure rises, and the influence of the pressure drop and pressure rise is on the drive pressure outlet. This will appear in the pressure waveform of the gas-driven pump 8.

A dashed line A in FIG. 2 shows a pressure waveform affected by such a pressure drop. In addition, the solid line B in the figure shows the pressure waveform when the tank capacity is sufficient, and the dotted line C shows the ideal pressure waveform.

As mentioned above, since the capacity of the tanks 3 and 4 needs to be sufficiently large, the equipment is mostly occupied by these tanks 3 and 4, which not only makes it difficult to downsize, but also increases the cost. It was hot.

The present invention has been made in view of the above circumstances, and its purpose is to provide a gas-driven pump that not only allows a gas-driven pump to operate as rated, but also reduces cost by downsizing the entire device. An object of the present invention is to provide a driving device for a driven pump.

That is, the present invention provides a gas pressure source that supplies a pressure higher than the positive pressure and/or a pressure lower than the negative pressure required by a gas-driven pump, and a gas pressure source that is switched between the gas pressure sources and a power amplifier. A solenoid valve device that controls the flow rate by changing the valve opening depending on the magnitude of the current value, and a current that is applied to the solenoid valve device according to the difference between the pressure on the outlet side of the solenoid valve device and the set pressure. The power amplifier is characterized by comprising a controller that controls the power amplifier.

Therefore, the capacity of the positive pressure tank and the negative pressure tank can be made as small as possible, or the entire apparatus can be downsized by omitting them.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram showing a first embodiment of the drive device of the present invention. In the figure, 9 is a compressor, 10 is a vacuum pump, 11 is a flow type electro-pneumatic proportional valve, 12 is a gas-driven pump, 13 is a power amplifier, 14 is a controller, 15 is a positive pressure tank, and 16 is a negative pressure tank It is.

The compressor 9 is connected to the positive pressure tank 15 and one port 20b on the inlet side of the electropneumatic proportional valve 11 via the flow path 17, and the vacuum pump 10 is connected to the negative pressure tank 1.
6. The other port 20 on the inlet side via the flow path 18
a, and the outlet side port 20c of the electropneumatic proportional valve 11 is connected to the gas-driven pump 12 via a flow path 19.

When ports 20b and 20c communicate, pressurized air is sent from compressor 9 to gas-driven pump 12, and when ports 20a and 20c communicate, air is sent from gas-driven pump 12 to vacuum pump 10. The gas is sucked in, and by repeating this alternately, the gas-driven pump 12 is driven.

Here, the compressor 9 is set to generate a positive pressure higher than the maximum positive pressure required by the gas-driven pump 12, and the vacuum pump 10 is set to generate a positive pressure higher than the minimum negative pressure required by the gas-driven pump 12. It is also set to generate a low negative pressure. This is done because pressure loss occurs due to air resistance in the flow paths 17 to 19, etc., and to provide enough margin for control with the electropneumatic proportional valve 11. Furthermore, the positive pressure tank 15 and the negative pressure tank 16 have a small role as conventional pressure sources, but rather act as buffer tanks, and for this reason, the tank capacity is several times the pump capacity of the gas-driven pump 12. It's only a matter of degree.

In addition, the electropneumatic proportional valve 11 has ports 20a and 20b.
In addition to switching operations, the opening degree of the port 20c (ports 20a, 20b) is changed.

FIG. 4 shows the electropneumatic proportional valve 11 in detail.
The electropneumatic proportional valve 11 includes a valve main body 20 equipped with the above-mentioned ports 20a to 20c, a valve spool 21, a spring 22 that urges the valve spool 21 in the direction of arrow A shown in the figure, and a spring 22 that urges the spool 21 in the direction of arrow A shown in the figure. 22 and a solenoid 23 that moves in the direction of arrow B shown in the figure, and the valve spool 21 is stopped and moved to an arbitrary position by the force balance between the solenoid 23 and the spring 22, and the valve spool 21 is moved to a desired position to open the port. The air flow rate is controlled by switching the ports 20a and 20b and changing the opening degree of these ports 20a and 20b.

FIG. 5 shows the relationship between the current value applied to the solenoid 23 and the opening degree of the ports 20a and 20b (the solid line shows the opening degree of the port 20a, and the dotted line shows the opening degree of the port 20b), and Figure 6 a~
c indicates the movement position of the valve spool 21. When the current value to the solenoid 23 is 0, the valve spool 21 is moved in the direction of arrow A by the elastic force of the spring 22, as shown in FIG. It will be fully opened.

When the current value applied to the solenoid 23 increases, the valve spool 21 is moved by the solenoid 23 in the direction of arrow B against the elastic force of the spring 22, and the port 20 is moved as shown by the solid line in FIG.
The aperture degree of b becomes smaller in proportion to the current value. Then, the port 20b becomes fully closed. At this time, the valve spool 21 is positioned as shown in FIG. 6b.

Furthermore, as the current value applied to the solenoid 23 increases, the degree of opening of the port 20a increases in proportion to the current value, as shown by the dotted line in FIG. When the current value reaches the maximum, the port 20a becomes fully open. At this time, the valve spool 21 is positioned as shown in FIG. 6c.

When the current value decreases, port 2
The opening degree of port 0a becomes smaller, and port 20a
When the current value becomes fully closed, the opening degree of the port 20b increases in proportion to the decrease in the current value, and when the current value becomes 0, the port 20b becomes fully open as described above.

The power amplifier 13 is controlled by the controller 14 to energize the solenoid 23 of the electropneumatic proportional valve 11 configured as described above. The controller 14 includes a setting signal generator 24 that generates a pulse signal corresponding to the pneumatic pulse acting on the gas-driven pump 12, and a gas-driven pump provided in the flow path 19 on the outlet side of the electropneumatic proportional valve 11. A pneumatic converter 25 that detects the air pressure acting on the pump 12, and an error comparator 2 that detects the difference between the signals of the setting signal generator 24 and the pneumatic converter 25.
It consists of 6. The error comparator 26 is composed of a plurality of operational amplifiers 26a to 26c.

Note that as the gas-driven pump 12, a blood pump device for an artificial heart is used. As shown in FIG. 7, for example, this blood pump device includes a pressure-resistant housing outer case 28 having a port 27 for introducing and discharging gas, and a flat bag-shaped blood chamber 29 provided in the upper part of the housing outer case 28. Tatsuba part 3
It is configured to be airtightly housed through the 0. A blood introduction conduit 31 and a blood discharge conduit 32 are erected in substantially parallel to the collar 30, and check valves 33 and 34 are provided in these blood introduction conduit 31 and blood discharge conduit 32. It is being Of course, other types of blood pumps may also be used.

Next, the operation of the above embodiment will be explained with reference to FIGS. 8a to 8c.

Now, when a signal of _H1 level is output from the setting signal generator 24, this signal is inverted by the operational amplifier 26a and becomes a signal of _L1 level. At this time,
In the flow path 19, since the vacuum pump 10 has just completed the suction operation, the operational amplifier 26 is transferred from the pneumatic converter 25.
An _L2 level signal is output to b. The signals from operational amplifiers 26a and 26b are operational amplifier 26c.
The signal is inverted at _H2 level and input to one terminal of the power amplifier 13.
3 to L ₃ level signals are output to the solenoid 23. That is, the current value supplied to the solenoid 23 becomes 0, and the port 20b is fully opened as described above, whereby compressed air is supplied from the compressor 9 into the outer case 28 of the blood pump device, which is the gas-driven pump 12. Blood chamber 2
Blood is pushed out from 9.

When the signal output from the pneumatic converter 25 increases as the pressure increases, the value of the current supplied from the power amplifier 13 increases sequentially from 0, and the degree of opening of the port 20b decreases, causing the inside of the outer case 28 to The amount of compressed air supplied decreases.

The signal output from the setting signal generator 24 is L ₄
When the level changes, the output of the power amplifier 13 becomes H ₃
level, the current value applied to the solenoid 23 becomes maximum, and the port 20a is fully opened as described above. As a result, air is sucked into the vacuum pump 10 from inside the outer case 28 and blood is introduced into the blood chamber 29.

When the signal output from the pneumatic converter 25 decreases as the pressure decreases, the current value decreases sequentially from the maximum value, and the opening degree of the port 20a decreases.

That is, when a rectangular pulse as shown in FIG. 8a is output from the setting signal generator 24, a current having a waveform as shown in FIG. The air pressure pulse shown is obtained.

The switching speed of the ports 20a and 20b is almost the same as that of a normal electromagnetic switching valve, and there is almost no problem of pressure drop or pressure increase during switching.

Therefore, the gas-driven pump 12 can be driven as rated without using a large-capacity tank like the conventional one.

FIG. 9 shows a second embodiment of the invention. This second embodiment differs from the first embodiment described above only in that the positive pressure tank 15 and negative pressure tank 16 are omitted, and the other configurations are the same.

In this way, the positive pressure tank 15 and the negative pressure tank 16
Even if this is omitted, the electropneumatic proportional valve 11 can drive the gas-driven pump 12 without any problem if operated as described above.

As in both of the above embodiments, the gas-driven pump 12
When using a blood pump device as a blood pump device, the pulse signal output from the setting signal generator 24 has a positive pressure, negative pressure, period, and duty ratio according to the characteristics of the blood pump device and the condition of the patient using the blood pump device. etc. will be set accordingly.

Furthermore, if the setting signal generator 24 is automatically controlled based on patient data (for example, blood pressure, blood flow, etc.), there is no need for doctors and nurses to constantly monitor the driving conditions of the device, and there is no fool-proof system for the patient. Treatment becomes safe.

In addition, although the said Example showed the case where the compressor 9 and the vacuum pump 10 were used, either one may be used. For example, when only the compressor 9 is used, the atmosphere becomes the negative pressure source, and the vacuum pump 10
When only the air is used, the atmosphere becomes the source of positive pressure.

In addition, the blood pump device is not limited to the sac type, but can also be applied to diaphragm type and other types.
It can also be applied to drive an intra-aortic balloon pump, etc. In this case, it is driven via a bellows, diaphragm, etc. It can also be used as a pressure wave generator.

As explained above, according to the present invention, there is provided a gas pressure source that supplies a pressure higher than the positive pressure and/or a pressure lower than the negative pressure required by a gas-driven pump, and a switching operation between the gas pressure source and the gas pressure source. At the same time, there is a solenoid valve device that controls the flow rate or pressure by changing the valve opening depending on the magnitude of the current value from the power amplifier, and a solenoid valve device that controls the flow rate or pressure by changing the valve opening depending on the magnitude of the current value from the power amplifier, and an electromagnetic valve device that controls the current according to the difference between the pressure on the outlet side of the solenoid valve device and the set pressure. Since it is equipped with a controller that controls the power amplifier so as to energize the valve device, the capacity of the positive pressure tank and the negative pressure tank can be made as small as possible, or the capacity of the negative pressure tank can be omitted to reduce the size of the entire device. be able to.

Further, by changing the setting signal, various gas pressure pulse waveforms can be obtained, and therefore, it can be used to drive various gas-driven pumps.

Next, specific examples of the present invention will be explained.

A sac-type blood pump device with a total capacity of 300 c.c. of the pump and tube is driven by the drive device (first embodiment of the present invention) shown in Fig. 3, and the pressure waveform inside the housing outer case is measured by a pressure transducer. As a result, the pressure wave rise was 90% at the maximum air pressure value of 100 to 300 mmHg and the minimum value of 10 to 50 mmHg.
value, a 50ms rectangular air pressure wave was obtained. The positive pressure tank 15, negative pressure tank 16, electropneumatic proportional valve 11, etc. used were as follows.

Positive pressure tank 15...tank capacity 2, maximum setting pressure 1.5Kg/cm ² , minimum 1.0Kg/cm ² .

Negative pressure tank 16...tank capacity 2, maximum setting pressure - 600mmHg, minimum 200mmHg.

Electropneumatic proportional valve 11...Valve opening area 13.8mm ² , coil resistance 26Ω, maximum current 750mA.

Pneumatic converter 25...Output 6mV/mmHg.

Setting signal generator 24...Outputs an arbitrary rectangular waveform with an output voltage of 0 to 15V at 0.3 to 3Hz and a duty ratio of 20 to 80%.

Power amplifier 13...Maximum 20V, 0.75V.

For comparison, similar measurements were made using the apparatus shown in Figure 1, but in this case, it took 100 mL for both the positive pressure tank and the negative pressure tank to obtain the rectangular air pressure wave as shown above. I needed more than that.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional device, Fig. 2 is a pressure waveform diagram, Fig. 3 is a block diagram showing a first embodiment of the present invention, Fig. 4 is a sectional view of an electropneumatic proportional valve, and Fig. 5 6 is a graph showing the relationship between the current value and the opening degree of the port, FIGS. 6 a to 6 c are explanatory diagrams of the operation of the electropneumatic proportional valve, FIG. 7 is an exploded perspective view of the sac-type blood pump device, and FIG. FIG. 9 is a diagram showing the output waveform from the set pressure generator, FIG. 9B is an output waveform diagram from the power amplifier, FIG. 9... Compressor, 10... Vacuum pump, 11... Solenoid valve device (electro-pneumatic proportional valve), 12... Gas-driven pump,
13...Power amplifier, 14...Controller, 17-19...
Flow path, 24... Setting signal generator, 25... Pneumatic converter, 26... Error comparator.

Claims (1)

[Claims] 1. A gas pressure source that supplies a pressure higher than the positive pressure and/or a pressure lower than the negative pressure required by a gas-driven pump, and the gas pressure source is switched and the current value from the power amplifier is adjusted. A solenoid valve device that controls the flow rate by changing the valve opening degree,
A gas-driven type, characterized by comprising a controller that controls the power amplifier so as to supply a current to the solenoid valve device according to the difference between the pressure on the outlet side of the solenoid valve device and the set pressure. Pump drive device.