JP2000227807A - Fluid flow controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid flow controller capable of attaining cost-down, being disposable and identifying a fluid by making the configuration of a flow sensor head part simple and compact while highly accurately controlling the distribution of the fluid by highly accurately detecting a fine flow rate. SOLUTION: This device is provided with a flow sensor head part 208 attached to a casing 206 having a conduit 202, a means for regulating the distribution of the fluid in the conduit 202 and a control means for calculating the flow rate value of the fluid in the conduit 202 on the basis of an electric signal from the head part 208 and controlling a fluid distribution regulating means. An electrode terminal 52 of the head part 208 and an electrode terminal 210a of a connector 214 are electrically connected/disconnected by attaching/detaching the connector 214 to/from the casing 206. The control means controls the fluid distribution regulating means so that the calculated flow rate value of the fluid in the conduit 202 can be a target flow rate value on the basis of the calculated flow rate value and the target flow rate value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid flow control technology, and more particularly to a fluid flow control device suitable for controlling a flow rate when supplying a fluid at a very small flow rate. INDUSTRIAL APPLICABILITY The fluid flow control device of the present invention can be applied to injection of a drug solution into a living body, blood transfusion, blood collection, addition of a reagent solution for chemical analysis, or addition of a raw material solution for a chemical reaction.

[0002]

2. Description of the Related Art
In the medical field, a medical solution is injected into a patient for treating a disease. As one method of injecting the medicinal solution, an infusion for continuously administering the medicinal solution at a minute flow rate over a considerable period of time is performed. Adjustment of the flow rate of the drug solution during infusion is performed by deforming the cross-sectional shape of a certain portion of a synthetic resin tube constituting the drug solution flow channel, and manually adjusting the degree of the deformation. Such a flow rate adjustment is simple and is preferable when high accuracy is not required for the injection flow rate (the amount of the drug solution injected per unit time).

However, depending on the type of treatment or the type of medical solution, it may be necessary to inject the medical solution while maintaining a predetermined flow rate with high precision. In this case, only gravity is used as the injection driving power source and manual operation is performed. The normal drip technique of adjusting the flow rate by the method is not sufficient. That is, in this method, the flow rate adjustment is actually performed only by the initial setting of the flow rate, and it is not possible to cope with the fluctuation of the chemical solution flow rate due to the movement of the patient or the change of the surrounding environment.

[0004] By supplying a chemical solution using a pump capable of supplying at a constant pressure, a certain degree of accuracy improvement can be obtained as compared with a case where only gravity is used as an injection driving force source.
The actual flow rate may fluctuate due to deformation of the tube constituting the chemical flow conduit, and this cannot be dealt with.

As one method for controlling the flow rate with high accuracy, it has been proposed to detect a flow rate and control a fluid supply pump so as to obtain a desired flow rate based on the detected flow rate value. As a method of detecting the flow rate used for such flow rate control, it is conceivable to count the number of infusions. However, in this method, the drop of the drug solution is discontinuous (in the case of a minute flow rate of 0.5 cc / min). , The interval between infusions becomes longer), so that continuous control of the flow rate cannot be performed, and high-precision flow control cannot be performed.

[0006] Therefore, it is preferable to always detect the flow rate of the chemical solution actually flowing in the flow conduit in order to realize high-accuracy flow control. For this purpose, it is preferable to perform measurement by bringing the detection section (flow rate sensor head section) of the flow rate sensor into contact with the chemical solution in the flow pipe. And
In this case, it is preferable that the flow conduit and the flow sensor head be integrated with each other so as not to lower the flow detection accuracy.

However, due to the nature of medical treatment, a fluid flow conduit (synthetic resin tube having an injection needle at the tip) for injecting a drug solution used for a certain patient must not be used for another patient. Must be discarded (disposable). Therefore, when the flow conduit and the flow sensor head are integrated, they will be collectively disposable.
In order to realize low cost, it is necessary to simplify the structure of the flow sensor head and reduce the size.

On the other hand, when injecting a drug solution into a living body as described above, a drug solution other than a desired drug solution must not be inadvertently injected. This may require that the fluid be identified as desired or not. However, providing such a means for fluid identification separately from the flow sensor is not preferable because it increases the cost of the apparatus.

The technical problem of controlling the flow rate itself when injecting a drug solution into a living body has been described above.
There is a similar technical problem when control is performed to stop the injection of the chemical based on the completion of the injection of the predetermined amount of the chemical that is detected by integrating the flow rates detected by the flow rate detection.

In the above description, the infusion of a drug solution into a living body has been exemplified. However, there are similar technical problems in injecting and collecting a biological fluid such as blood transfusion into a living body or blood collection from a living body. Further, there is a similar technical problem in flow rate control and reagent stop control when adding a reagent solution for chemical analysis.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fluid flow control device that controls fluid flow with high accuracy based on a flow value obtained by detecting a fluid flow rate. In particular, it is an object of the present invention to provide a fluid flow control device capable of performing flow detection with high accuracy and performing high-precision flow control even if the fluid flow rate is minute.

Further, the present invention simplifies the structure of the flow sensor head in the fluid flow control device, reduces the size and lowers the cost, and in fact can dispose the flow sensor head together with at least a part of the flow pipe. It is to make.

Still another object of the present invention is to provide a fluid flow control device capable of discriminating whether or not a fluid whose flow rate is to be controlled is a predetermined measurement object.

A further object of the present invention is to provide a fluid flow rate control device capable of preventing an excessive rise in temperature of a fluid whose flow rate is controlled, and preventing a problem such as deterioration of the fluid or a flash explosion. It is in.

[0015]

According to the present invention, there is provided a flow sensor head mounted on a casing having a fluid flow conduit, which achieves the above objects.
A fluid flow adjusting means for adjusting the flow of the fluid in the fluid flow conduit; and calculating a flow value of the fluid in the fluid flow conduit based on an electric signal from the flow sensor head, and calculating the flow value based on the flow value. Control means for controlling the fluid flow adjusting means, a connector having one end connected to the casing and having the other end of a cable connected to the control means, the connector being detachably attached to the casing. Thus, an electrical connection / disconnection between the electrode terminal of the flow sensor head and the other end of the cable of the connector is provided.

In one aspect of the present invention, the control means controls the calculated flow rate value of the fluid in the fluid flow conduit to be the target flow rate value based on the calculated flow rate value and the target flow rate value. The fluid flow control means is controlled.

In one aspect of the present invention, the electrode terminals of the flow sensor head portion extend along the mounting / dismounting direction on a side surface of a convex portion extending along the mounting / detaching direction of the connector to / from the casing. A concave portion corresponding to the convex portion is formed in the connector, and an electrode terminal at the other end of the cable is disposed in the concave portion at a position corresponding to the electrode terminal of the flow rate sensor head portion. ing.

In one aspect of the present invention, the casing comprises a main body in which the fluid flow conduit is formed and a lid attached to the main body, and the lid includes the casing for the connector. An intermediate connector for attaching and detaching the connector is formed, and one end of the intermediate connector is connected to an electrode terminal of the flow sensor head portion, and an electrical connection and disconnection with the other end of the cable of the connector are performed. The other end.

In one embodiment of the present invention, the control means calculates an integrated flow rate based on the calculated flow rate of the fluid, and when the integrated flow rate reaches a target integrated flow rate, the fluid flow line The fluid flow control means is controlled so as to stop the flow of the fluid inside.

In one embodiment of the present invention, the flow sensor head has a flow detecting section having a heat generating function and a temperature sensing function, and a flow detecting section for receiving the influence of the heat generated by the flow detecting section and flowing the fluid to be detected. A flow rate detecting heat transfer member arranged to extend into the fluid flow path, wherein the flow rate detecting portion is formed on the flow rate detecting heat transfer member outside the fluid flow path. And a flow rate detecting thin film temperature sensing element disposed so as to be affected by the heat generated by the thin film heating element. A temperature sensing effected by heat absorption by the fluid to be detected is executed, and an electric signal corresponding to a flow rate of the fluid to be detected in the fluid flow conduit can be generated based on a result of the temperature sensing. is there.

In one embodiment of the present invention, the control means includes heat generation control means disposed on an energization path to the thin film heating element to control heat generation of the thin film heating element. The current supply to the thin film heating element is controlled so that an electric signal emitted from the flow sensor head and corresponding to the flow rate of the fluid to be detected matches a target.

In one embodiment of the present invention, the control means controls the fluid flow adjusting means to introduce a fluid into the fluid flow pipe to stop the flow of the fluid, An electrical signal emitted from the sensor head unit and corresponding to the flow rate of the detected fluid is compared with a threshold to identify which of the preset fluid types is in the fluid flow conduit. Things.

In one embodiment of the present invention, the heat transfer member for detecting a flow rate is formed in a flat plate shape, extends in a radial direction of the fluid passage, and passes through a center line of the fluid passage. Are arranged along the direction of the fluid passage in the fluid passage.

In one embodiment of the present invention, a fluid temperature sensor head for performing temperature compensation upon detecting the flow rate is attached to the casing, and the fluid temperature sensor head includes a fluid temperature detector. The fluid temperature detecting section and the fluid temperature detecting heat transfer member arranged to extend into the fluid flow conduit are thermally connected, and by attaching and detaching the connector to and from the casing. Electrical connection / disconnection between the electrode terminal of the fluid temperature sensor head and the other end of the cable of the connector is performed in the same manner as the electrode terminal of the flow sensor head.

In one embodiment of the present invention, the heat transfer member for detecting fluid temperature has a flat plate shape, extends in a radial direction of the fluid passage, and passes through a center line of the fluid passage. And is disposed along the direction of the fluid flow passage in the fluid flow passage.

In one embodiment of the present invention, the fluid flow adjusting means is a pump for driving the flow of the fluid in the fluid flow conduit.

[0027]

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

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of a fluid flow control device according to the present invention. The present embodiment is used to control the flow rate of the injected drug solution when injecting the drug solution into the living body.

In FIG. 1, reference numeral 200 denotes a fluid reservoir containing a chemical solution to be injected, and the fluid reservoir 200 has a synthetic resin tube 202 serving as a flow path of a fluid to be injected.
Are connected at one end (upper end). An injection needle 204 is connected to the other end of the tube 202. Tube 2
In the middle of 02, a casing 206 constituting the fluid flow control device is interposed, and a flow sensor head unit 208 is connected to the casing. Although not shown, the casing 206 is also connected to a temperature detection sensor head. The temperature detection sensor head and the flow sensor head 208 are connected to a control unit (control panel) 212 via a cable 210. The flow sensor head 208 and the temperature sensor head are connected to the connector 2 attached to the end of the cable 210.
14 electrically and mechanically.

A pump 216 for driving fluid flow in the tube 202 is detachably attached to the tube 202. The pump is, for example, a tube pump,
By adjusting the number of revolutions of the rotor, the flow of the fluid can be adjusted, and the flow rate can be adjusted including the stop of the flow of the fluid. The tube 202 is also detachably attached with a fluid flow control unit 218 that controls the flow of fluid in the tube by clamping the tube. The pump 216 and the fluid flow control unit 218 are connected to the control unit 212 by cables 220 and 222, respectively.

As shown in FIG. 1, the control means 212 includes an operation switch 212a for setting the type of the fluid to be injected, a desired flow rate, a desired integrated flow rate, etc. A display unit 212b for displaying the integrated fluid flow value, the set fluid flow value, the integrated fluid flow value, and the like.
And a lamp (a kind of display unit) 212c for issuing a warning when the detected fluid type is other than the desired one.

FIG. 2 shows the casing 206 shown in FIG.
FIG. 4 is a cross-sectional view showing a state where the flow rate sensor head unit 208 and the fluid temperature sensor head unit are attached to the fluid supply line, and shows a cross section along a fluid flow passage through which fluid flows.

In FIG. 2, reference numeral 2 denotes a casing body, and a fluid circulation pipe 4 for circulating a fluid to be detected is formed through the casing body. The pipe 4 extends to both ends of the casing body 2. A indicates the center line of the pipeline 4. The casing body 2 is made of synthetic resin, for example, vinyl chloride resin, glass fiber reinforced polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polycarbonate (PC), or the like having high chemical resistance and oil resistance.

In the present embodiment, the casing body 2
Two element unit holding portions 50 and 60 are formed adjacent to the pipe 4 at positions separated along the pipe 4. Each of these element unit holding portions 50 and 60 has a two-stage cylindrical inner surface centered on the radial direction of the pipeline 4. The flow rate detection unit (flow rate sensor head) 51 is held by the first element unit holding section 50, and the second
The fluid temperature detecting unit (fluid temperature sensor head) 61 is held by the element unit holding section 60 of FIG.

A holding plate 32 for the flow rate detecting unit 51 and the fluid temperature detecting unit 61 is arranged on the casing body 2, and the lid 26 is fixedly arranged thereon. The casing is composed of the casing body 2 and the lid 26.

FIG. 3 is a sectional view of the flow rate detection unit 51. As shown in FIG.
Reference numeral 1 denotes a flow rate detecting unit 12, a fin plate 14 as a heat transfer member joined to the flow rate detecting unit 12 by a bonding material 16 having good thermal conductivity, an electrode terminal 52, and an electrode of the flow rate detecting unit 12. It has a bonding wire 28 electrically connected to the corresponding electrode terminal 52 and a base 53 made of synthetic resin. The base portion 53 is preferably made of a synthetic resin having a low heat transfer property (that is, having thermal insulation properties) and a high chemical resistance and a high oil resistance. The base portion 53 has a two-stage cylindrical outer peripheral portion having a shape corresponding to the inner peripheral surface of the element unit holding portion 50. From the base portion 53, a part of the fin plate 14 extends toward the conduit 4 and a part of the electrode terminal 52 extends on the side (outside) opposite to the conduit 4. That is, the flow rate detector 12, the bonding material 16, a part of the fin plate 14, a part of the electrode terminal 52, and the bonding wire 28 are sealed by the base 53.

The upper portion of the base portion 53 is formed as a semi-cylindrical convex portion, and a single planar surface portion of the electrode terminal 52 is exposed on the planar surface portion. The upper convex portion of the base portion 53 extends through the openings formed in the holding plate 32 and the lid portion 26 to the outside of the casing. The electrode terminal 52 extends in parallel with the axial direction of the two-stage cylindrical shape of the base portion 53.

The fluid temperature detecting unit 61 shown in FIG. 2 is basically different from the flow rate detecting unit 51 in that a fluid temperature detecting unit is used instead of the flow rate detecting unit 12. That is, the fluid temperature detection unit 61 includes a fin plate 14 ′ as a heat transfer member joined to the fluid temperature detection unit with a joining material having good heat conductivity, an electrode terminal 62,
It has a bonding wire for electrically connecting the electrode of the fluid temperature detecting section to the corresponding electrode terminal 62, and a base section made of synthetic resin. The shape of the base part is the flow rate detection unit 51.
Similarly, the semi-cylindrical upper projection extends through the openings formed in the holding plate 32 and the lid 26 to the outside of the casing.

O-rings 54 and 64 as seal members for the pipeline 4 are provided between the outer peripheral surfaces of the flow rate detecting unit 51 and the fluid temperature detecting unit 61 and the inner peripheral surfaces of the element unit holding portions 50 and 60, respectively. Is interposed.

FIG. 4 shows the casing 206 and the connector 21.
FIG. 4 is an exploded perspective view showing an engagement relationship with No. 4. In this figure, the fluid temperature detection unit 61 is not shown, but is arranged in the same attitude as the flow rate detection unit 51 as described above.

The connector 214 has a flow detection unit 5
The concave portion 2 having a shape corresponding to the semi-cylindrical convex portion of the base portion and the semi-cylindrical convex portion of the base portion of the fluid temperature detecting unit 61.
14a and 214b are formed. The electrode terminal 2 of the flow rate detection wiring of the cable 210 facing the inside of the concave portion 214a.
10a is exposed. The electrode terminal 210a is arranged at a position corresponding to the electrode terminal 52 of the flow detection unit 51. An electrode terminal (not shown) of the fluid temperature detecting wiring of the cable 210 is exposed and disposed facing the inside of the concave portion 214b. The electrode terminals are arranged at positions corresponding to the electrode terminals of the fluid temperature detection unit 61.

The casing 206 has engaging portions 20 on both sides.
6a, corresponding to the connector 214
Are formed with engaging portions 214c on both sides. The engaging portion 214c can be elastically opened outward at the end on the casing side, and the connector 214 can be fixed elastically to the engaging portion 206a. When the connector is fixed, the flow rate sensor head 208 and the fluid temperature sensor head are fitted in the recesses 214a and 214b, respectively, and the electrical connection between the electrode terminals of these heads and the electrode terminals of the cable 210 is secured. Is done.
By opening the tip of the engaging portion 214c outward, the engagement between the engaging portion 214c and the engaging portion 206a can be easily released.

As shown in FIG. 5, the flow rate detecting section 12 has an insulating layer 12 on the upper surface (first surface) of the substrate 12-1.
-2, and a thin film temperature sensing element 12-7 for flow rate detection is formed thereon.
Is formed thereon, an insulating layer 12-6 is formed thereon, and a thin-film heating element 12-3 and a pair of electrode layers 12-4 and 12-5 for the thin-film heating element are formed thereon. Insulating layer 12 on top
-8, and a pair of electrode layers 12- for the bonding portion of the thin film temperature sensing element 12-7 for flow rate detection and the thin film heating element.
Pad layer 12 covering 4, 12-5 bonding portions
-9 is formed in a chip shape. Substrate 12-1
Is about 0.5mm thick and 2-3mm in size
It is possible to use a silicon or alumina material having a square shape (when using an insulating substrate such as alumina, the insulating layer 12-2 can be omitted). A cermet patterned to a desired shape with a thickness of about 1 μm can be used, and the electrode layers 12-4 and 12-5 have a thickness of 0.5 μm.
About nickel or about 0.1 μm thick
Can be used, and the insulating layer 1
As 2-2, 12-6, and 12-8, those made of SiO ₂ having a film thickness of about 1 μm can be used. As the thin film thermosensitive body 12-7, a film having a thickness of about 0.5 to 1 μm and having a desired shape, for example, A stable metal resistance film having a large temperature coefficient such as platinum or nickel patterned in a meandering shape can be used (or a manganese oxide-based NTC thermistor can be used). The pad layer 12-9 may be made of gold. As described above, since the thin-film heating element 12-3 and the thin-film thermosensitive element 12-7 are disposed very close to each other with the thin-film insulating layer 12-6 interposed therebetween, the thin-film thermosensitive element 12-7 is thin-film. The heating element 12-3 is immediately affected by the heat generated.

As shown in FIG. 3, the flow rate detector 1
2, a flat fin plate 14 as a heat transfer member is provided on one surface of the substrate 2, ie, the second surface of the substrate 12-1.
It is joined by. The fin plate 14 may be a flat plate made of, for example, copper, duralumin, or a copper-tungsten alloy, and the joining material 16 may be, for example, a silver paste.

The fin plate 14 has an upper part joined to the flow rate detector 12 and a lower part extending into the pipeline 4. The fin plate 14 extends across the line 4 from the top to the bottom as shown in FIG. 2 through the center in the cross section of the line 4 having a substantially circular cross section. However, the pipe 4 does not necessarily have to have a circular cross section, and may have an appropriate cross section. In conduit 4,
The width (dimension in the pipe direction) of the fin plate 14 is sufficiently larger than the thickness of the fin plate 14. For this reason, the fin plate 14 can satisfactorily transfer heat between the flow rate detection unit 12 and the fluid without significantly affecting the flow of the fluid in the pipeline 4.

The temperature detecting section is formed in a chip shape in which a similar thin-film thermosensitive element (a thin-film thermosensitive element for fluid temperature compensation) is formed on the same substrate as the flow rate detecting section 12. That is, the temperature detecting section can be configured in the same manner as in FIG. 5 except that the thin film heating element 12-3, the pair of electrode layers 12-4, 12-5, and the insulating layer 12-6 are removed. Further, the fin plate 14 ′ is joined to the temperature detecting section by a joining material in the same manner as the flow rate detecting section 12.

FIG. 6 is a block diagram showing the configuration of the control means 212 of this embodiment.

The externally input AC 100 V is converted into DC 5 V by the power supply circuit. In the analog section, a flow sensor (the flow sensor head section 208: 51) and a temperature compensation sensor (the fluid temperature sensor head section 6)
An analog electric signal corresponding to the flow rate output is generated by an electric circuit including (1) as a part. This analog signal is converted into a digital signal by an AD converter and input to a microcomputer. The microcomputer performs flow rate calculation, integrated flow rate calculation, fluid identification, etc.
Based on these results, the infusion pump (the pump 216) and the fluid flow control unit 218 are controlled via the DA converter. In addition, a display and a warning are displayed on the display unit (the display unit 212b and the lamp 212c) via the display unit driver. A desired fluid type, a target flow value, a target integrated flow value, and the like are input to the microcomputer by operation switches. The microcomputer is connected to a monitoring terminal (for example, located at a nurse's station in a hospital) via the SIO.

FIG. 7 is a circuit diagram showing a configuration of the analog section including a flow sensor head section and a fluid temperature sensor head section. With reference to FIG. 7 and other drawings, the flow rate detection and fluid identification and the flow rate control operation based on these in this embodiment will be described.

In FIG. 7, the power supply is a constant voltage circuit 10.
2 is supplied. The output of the constant voltage circuit 102 is supplied to a bridge circuit 104. The bridge circuit 104 includes a thin film temperature sensing element 104-1 for flow rate detection and the thin film temperature sensing element 10 for temperature compensation.
4-2 and the variable resistors 104-3 and 104-4.

The voltages at points a and b of the bridge circuit 104 are input to the differential amplifier circuit 106. The differential amplifier circuit 106
Is made variable by a variable resistor 106a. The output of the differential amplification circuit 106 is input to the integration circuit 108. The differential amplification circuit 106 and the integration circuit 108 with variable amplification factors function as responsiveness setting means.

On the other hand, the power supply is connected to the collector of the NPN transistor 110, and the emitter of the transistor 110 is connected to the heating element 112. The output of the integration circuit 108 is input to the base of the transistor 110. That is, the power supply supplies current to the thin-film heating element 112 via the transistor 110, and the voltage applied to the heating element 112 is
It is controlled by a partial pressure of zero. And transistor 1
The voltage divided by 10 is controlled by the output of the integrating circuit 108 input to the base via the resistor, and the voltage of the transistor 11
Numeral 0 functions as a variable resistor, and functions as heat generation control means for controlling heat generation of the heat generating element 112. Thin film heating element 112
As a signal indicating the state of controlling the energization of
Is used. This signal is an analog electric signal corresponding to the flow rate output.

In the flow rate detecting section 12, based on the heat generated by the thin film heating element 12-3 (112 in FIG. 7) shown in FIG. 12-7 thin film thermosensitive element
(104-1 in FIG. 7) is executed. Then, as a result of the temperature sensing, a, b of the bridge circuit 104
The difference between the voltages Va and Vb at the point is obtained.

The value of (Va-Vb) changes when the temperature of the thin film temperature sensing element 104-1 for flow rate detection changes according to the flow rate of the fluid. Variable resistors 104-3, 104-4 in advance
By appropriately setting the resistance value, the value of (Va-Vb) can be made zero in the case of a desired fluid flow rate serving as a reference. At this reference flow rate, the output of the differential amplifier circuit 106 is zero, the output of the integration circuit 108 is constant, and the resistance value of the transistor 110 is also constant. In this case, the partial pressure applied to the heating element 112 is also constant, and the flow rate output at this time indicates the reference flow rate.

When the fluid flow rate increases or decreases from the reference flow rate, the output of the differential amplifier circuit 106 differs depending on the polarity (the resistance-temperature characteristic of the flow rate detecting temperature sensing element 104-1) according to the value of (Va-Vb). ) And the magnitude changes, and the output of the integration circuit 108 changes accordingly. The rate of change of the output of the integrating circuit 108 is determined by the variable resistor 106a of the differential amplifier 106.
Can be adjusted by setting the amplification factor. The response characteristics of the control system are set by the integrating circuit 108 and the differential amplifier circuit 106.

When the fluid flow rate increases, the temperature of the flow sensing temperature sensing element 104-1 decreases, so that the amount of heat generated by the heating element 112 is increased (that is, the amount of current is increased).
From the integration circuit 108, a control input is made to the base of the transistor 110 so as to reduce the resistance of the transistor 110.

On the other hand, when the fluid flow rate decreases, the temperature of the flow rate detecting temperature sensing element 104-1 increases.
12 to reduce the amount of heat generation (that is, reduce the amount of current)
As described above, a control input for increasing the resistance of the transistor 110 is made from the integration circuit 108 to the base of the transistor 110.

As described above, the heat generation of the heating element 112 is feedback-controlled so that the temperature detected by the flow rate detecting temperature sensing element 104-1 always becomes the target value regardless of the change in the fluid flow rate. (If necessary, the polarity of the output of the differential amplifier circuit 106 is appropriately inverted according to the positive / negative of the resistance-temperature characteristic of the temperature sensing element 104-1 for flow rate detection).

FIG. 8 shows that the detected fluid is water, ethanol,
In the case of 0% saline solution and 10% saline solution, how the value of the flow rate output [V], which is the voltage applied to the heating element 112, changes when the flow rate value changes. It is shown.

First, the control means 212 controls the fluid flow control means (the pump 216 and the fluid flow control section 218) to introduce the fluid into the tube 202, and to flow the fluid through the fluid flow pipe 4 in the casing 2. Is satisfied, the flow of the fluid is stopped, and the type of the detected fluid is identified as one of the preset ones. As shown in FIG. 8, the output value with respect to the flow rate differs depending on the type of the fluid, and although not explicitly shown in the figure, the flow rate is 0 [cc /
min], the output value is 2.23 [V] when the fluid is air, 2.86 [V] when the fluid is ethanol, and when the fluid is water. The output value is 3.03 [V], the output value is 3.15 [V] when the fluid is 10% saline, and the output value when the fluid is 20% saline. Is 3.16 [V]
It is.

The control means 212 has an EPR as a storage means.
In OM, for a plurality of fluids that are expected to be distributed in advance,
A threshold value intermediate between these values is set for the output value when the flow rate is 0, and the magnitude relationship between the flow rate output actually detected when the flow rate is 0 and a plurality of threshold values stored in the EPROM is set. The comparison identifies which of the preset fluids is detected.

Whether the fluid to be detected is desired or not is determined by
It can be set by the operation switch. When an undesired fluid is detected, the display unit (warning lamp 212)
c). This can prevent injection when air is mixed in the injection fluid or when a fluid other than the desired injection fluid is excessively supplied from the fluid reservoir 200.

The above-described fluid discrimination utilizes the fact that heat transfer differs based on the difference in specific heat and heat conductivity depending on the type of fluid, and such a difference in heat transfer is remarkable. A plurality of fluids can be distinguished from each other.

In the above-described fluid identification, when it is detected that the fluid is desired, the control means 2
12 controls the pump 216 and the fluid flow control unit 218 to resume fluid flow in the tube 202,
Perform fluid injection from. The flow rate of the fluid is detected by the control means 212. That is, a calibration curve indicating the relationship between the flow rate and the output value for a plurality of fluids as shown in FIG. 8 is stored in advance in the EPROM, and corresponds to the output value relating to the fluid determined to be desired by the fluid identification. To obtain the flow value. This can be displayed on the display unit.

The detected flow rate value is compared with a target flow rate value set in advance by an operation switch, and based on the comparison, the fluid flow rate is set so that the calculated flow rate value of the fluid in the fluid flow conduit becomes the target flow rate value. Control the flow control means.

The detected flow value is integrated to calculate a flow integrated value, which can be displayed on the display unit. When the flow integrated value reaches the target flow integrated value, the flow rate in the fluid flow conduit is reduced. It is also possible to control the fluid flow adjusting means so as to stop the flow of the fluid.

In the above embodiment, regardless of the flow rate of the fluid to be detected, the temperature of the flow rate detecting temperature sensing element 104-1 around the heating element 112 is maintained substantially constant. It is possible to prevent deterioration of the fluid to be detected and prevent occurrence of ignition explosion of the flammable fluid to be detected. Further, since the heating element 112 does not require a constant voltage circuit, there is an advantage that a low output constant voltage circuit 102 for the bridge circuit 104 may be used. Therefore, the calorific value of the constant voltage circuit can be reduced, and the flow rate detection accuracy can be maintained satisfactorily even if the flow rate sensor head is downsized.

Further, in this embodiment, since the flow rate detecting section 12 is a chip-shaped one in which a thin-film heating element and a thin-film temperature sensing element are laminated, the responsiveness is good and the flow rate with high accuracy is high. Detection and fluid identification can be performed, and based on this, flow control with high accuracy and high-speed response can be performed.

The connector 214 and the casing 20
6 can be easily attached and detached, and at the time of attachment / detachment, the electrode terminals of the sensor head and the cable end are electrically connected and disconnected, so that the sensor head can be attached together with the casing 206 and the tube 202. Disposable,
Other components can be used repeatedly.

In this embodiment, the fin plate 1
4, 14 'extend in the radial direction of the fluid flow conduit and pass through the center line A of the fluid conduit, so that even when the fluid is a viscous fluid, it is possible to accurately detect the flow rate and identify the fluid.

FIGS. 9 and 10 are views showing another embodiment of the fluid flow control device according to the present invention. These figures are
2 and 4 of the embodiment described with reference to FIGS.
It is a figure which shows the same part as. This embodiment differs from the above-described embodiments of FIGS. 1 to 8 only in the portions shown in FIGS. 9 and 10, and the other portions are the same.

FIG. 9 is a sectional view showing a state where the flow rate sensor head and the fluid temperature sensor head are attached to the casing, and FIG. 10 is an exploded perspective view showing an engagement relationship between the casing and the connector. In these figures, parts having the same functions as those in FIGS. 2 and 4 are denoted by the same reference numerals.

In the present embodiment, the flow sensor head 2
08 '(51') and fluid temperature sensor head 61 '
Is a flow sensor head unit 208 shown in FIGS.
It differs from (51) and the fluid temperature sensor head 61 in that the base has no upper convex portion. In the present embodiment, the casing 206 has the outer lid 8. In the present embodiment, the casing has a main body including the lid portion 26, and the outer lid 8 serving as a lid is attached to the main body. A wiring board 26 ′ is attached to the outer lid 8, and the flow sensor head 2 is attached to the wiring board 26 ′.
The electrode terminal 52 of the fluid temperature sensor head part 61 'is connected to the electrode terminal 52 of the fluid temperature sensor head 08' (51 ').

An intermediate connector 230 for attaching / detaching the casing to / from the connector 214 'is formed on the outer lid 8. The wiring of the intermediate connector 230 has one end connected to the wiring board 26' and the other end connected. An electrode terminal 230a is provided for electrical connection / disconnection with the electrode terminal at the end of the cable of the connector 214 '.

The connector 214 ′ and the intermediate connector 230 are easily fitted by being pushed in, so that the electrode terminal of the head portion and the cable 2 are connected via the wiring board 26 ′.
Electrical connection with the ten electrode terminals is secured. The engagement between the connector 214 'and the intermediate connector 230 can be easily released by pulling out.

The operation of this embodiment is the same as that of the embodiment shown in FIGS. In the present embodiment, the connector 21 is connected via the intermediate connector 230 fixed to the casing.
4 ′ and the sensor head, the cable 210 is connected and disconnected when the connector is attached and detached and when the device is used.
Therefore, even if an external force is applied, the force is not directly transmitted to the sensor head, and the safety of the device is improved.

In the above embodiment, the injection of a drug solution into a living body has been described as an example. However, the present invention can also be applied to flow rate control at the time of injecting or collecting a biological fluid such as blood transfusion into a living body or blood sampling from a living body. . Further, the present invention can also be applied to flow rate control and reagent addition stop control when a reagent solution for chemical analysis is added.

[0078]

As described above, according to the flow rate control device of the present invention, a high precision fluid flow rate is detected even if the fluid flow rate is very small, and the fluid flow can be controlled with high precision based on the flow rate value obtained thereby. In addition, control can be performed with high-speed response.

Further, according to the present invention, it is possible to simplify the configuration of the flow sensor head in the fluid flow control device, to reduce the size and cost, and to dispose the flow sensor head together with at least a part of the flow pipe. Can be enhanced.

Further, according to the present invention, it is possible to identify whether or not the fluid whose flow rate is to be controlled is a predetermined measurement object.

Further, according to the present invention, it is possible to prevent an excessive rise in temperature of the fluid whose flow rate is controlled, and to prevent the occurrence of troubles such as deterioration of the fluid and a flash explosion.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an embodiment of a fluid flow control device according to the present invention.

FIG. 2 is a cross-sectional view showing a state where a flow sensor head and a fluid temperature sensor head are mounted on a casing shown in FIG.

FIG. 3 is a cross-sectional view of a flow detection unit.

FIG. 4 is an exploded perspective view showing an engagement relationship between a casing and a connector.

FIG. 5 is an exploded perspective view of a flow detection unit of the flow sensor.

FIG. 6 is a block diagram illustrating a configuration of a control unit.

FIG. 7 is a circuit diagram showing a configuration of an analog unit including a flow sensor head unit and a fluid temperature sensor head unit.

FIG. 8 is a graph showing a relationship between a flow value and a flow output value.

FIG. 9 is a cross-sectional view showing a mounting state of a flow sensor head and a fluid temperature sensor head to a casing in another embodiment of the fluid flow controller according to the present invention.

FIG. 10 is an exploded perspective view showing an engagement relationship between a casing and a connector.

[Explanation of symbols]

 Reference Signs List 2 Casing main body part 4 Fluid flow conduit 5 Element housing part 8 Casing outer lid 12 Flow rate detecting part 12-1 Substrate 12-2 Insulating layer 12-3 Thin film heating element 12-4, 12-5 Electrode layer 12-6 Insulating layer 12-7 Thin film temperature sensing element for flow rate detection 12-8 Insulating layer 14, 14 'Fin plate 16 Bonding material 26 Lid portion 26' Wiring board 28 Bonding wire 30 External lead wire 32 Holding plate 50 Element unit holding portion 51, 51 'Flow rate detecting unit 52 Electrode terminal 53 Base part 54 O-ring 60 Element unit holding part 61, 61' Fluid temperature detecting unit 62 Electrode terminal 63 Base part 64 O-ring 104-1 Flow rate detecting thin film temperature sensing element 104-2 Temperature compensation thin-film thermosensitive element 112 Thin-film heating element 200 Fluid reservoir 202 Tube 204 Injection needle 206 Casing 20 a Engaging section 208, 208 'Flow rate sensor head section 210 Cable 212 Control means 212a Operation switch 212b Display section 212c Lamp 214 Connector 214a, 214b Concave section 214c Engaging section 216 Pump 218 Fluid flow control section 220, 222 Cable 230 Intermediate connector 230a Electrode terminal A Pipe center line

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kiyoshi Yamagishi 1333-2, Hara-shi, Ageo-shi, Saitama F-term (reference) 2F035 EA04 EA08 5H307 AA14 AA15 BB01 BB05 BB16 DD10 DD11 DD12 DD20 EE22 FF06 FF15 GG11 GG13 GG15 HH04 HH11 HH12

Claims (13)

[Claims] 1. A flow sensor head mounted on a casing having a fluid flow conduit, a fluid flow adjusting means for regulating the flow of fluid in the fluid flow conduit, and an electric signal from the flow sensor head. Control means for calculating a flow rate value of the fluid in the fluid flow path based on the flow rate value, and controlling the fluid flow control means based on the flow rate value. One end of the casing is connected to the control means. A connector having the other end of the cable is detachably mounted, and the connection and disconnection of the electrode terminal of the flow sensor head portion and the other end of the cable of the connector are performed by attaching and detaching the connector to and from the casing. A fluid flow control device characterized in that: 2. The control means according to claim 1, wherein said control means controls said fluid flow control means so that a calculated flow value of the fluid in said fluid flow conduit is equal to said target flow value based on said calculated flow value and said target flow value. The fluid flow control device according to claim 1, wherein the control is performed. 3. An electrode terminal of the flow sensor head portion is disposed on a side surface of a convex portion extending along a direction in which the connector is attached to and detached from the casing, and is arranged along the attachment and detachment direction. A concave portion corresponding to the convex portion is formed on the connector, and an electrode terminal at the other end of the cable is disposed in the concave portion at a position corresponding to the electrode terminal of the flow rate sensor head. To claim 1
3. The fluid flow control device according to any one of 2. 4. The casing comprises a main body in which the fluid flow conduit is formed, and a lid attached to the main body. The lid has a lid for attaching and detaching the casing to and from the connector. An intermediate connector is formed, and the intermediate connector has one end connected to an electrode terminal of the flow rate sensor head portion and the other end of a wiring for electrical connection / disconnection with the other end of the cable of the connector. The fluid flow control device according to claim 1, wherein: 5. The control means calculates a flow rate integrated value based on the calculated flow rate value of the fluid, and when the flow rate integrated value reaches a target flow rate integrated value, controls the flow of the fluid in the fluid flow conduit. The fluid flow control device according to any one of claims 1 to 4, wherein the fluid flow adjusting means is controlled so as to stop. 6. The flow rate sensor head section includes a flow rate detection section having a heat generation function and a temperature sensing function, and a flow rate detection head section which is affected by heat generation in the flow rate detection section and is provided in a fluid flow passage for flowing a fluid to be detected. A flow rate detecting heat transfer member disposed so as to extend, and the flow rate detecting section is a thin film heating element formed on the flow rate detecting heat transfer member outside the fluid flow conduit. A flow rate detecting thin film temperature sensing element disposed so as to be affected by the heat generated by the thin film heating element, and the fluid to be detected via the flow rate detecting heat transfer member based on heat generation in the flow rate detecting section. A temperature sensing effected by heat absorption is performed, and an electric signal corresponding to the flow rate of the fluid to be detected in the fluid flow conduit can be generated based on the result of the temperature sensing. Claim 1
6. The fluid flow control device according to any one of 5. 7. The control means includes heat generation control means disposed on a current supply path to the thin film heating element to control heat generation of the thin film heating element, wherein the heat generation control means emits heat from the flow sensor head. And controlling the energization of the thin film heating element so that an electric signal corresponding to the flow rate of the fluid to be detected matches a target.
7. The fluid flow control device according to any one of 6. 8. The control unit controls the fluid flow control unit to introduce a fluid into the fluid flow conduit to stop the flow of the fluid, and then emits the fluid from the flow sensor head unit. A comparison is made between an electric signal corresponding to the flow rate of the detected fluid and a threshold value to identify which of the preset fluid types is in the fluid flow conduit. The fluid flow control device according to any one of claims 1 to 7, wherein 9. The heat transfer member for flow rate detection is formed in a flat plate shape, extends in a radial direction of the fluid passage, passes through a center line of the fluid passage, and is connected to the fluid passage. The fluid flow control device according to any one of claims 6 to 8, wherein the fluid flow control device is disposed along the direction of the pipe in the inside. 10. A fluid temperature sensor head for performing temperature compensation at the time of the flow rate detection is attached to the casing, wherein the fluid temperature sensor head includes a fluid temperature detector, and the fluid temperature A detection unit and a heat transfer member for detecting fluid temperature that are arranged to extend into the fluid flow conduit are thermally connected, and the flow sensor head unit is connected to and detached from the casing by the connector. The electrical connection / disconnection between the electrode terminal of the fluid temperature sensor head and the other end of the cable of the connector is performed in the same manner as in the case of the electrode terminal. The fluid flow control device according to any of the preceding claims. 11. The heat transfer member for detecting fluid temperature has a flat plate shape, extends in a radial direction of the fluid passage, and passes through a center line of the fluid passage. The fluid flow control device according to claim 10, wherein the fluid flow control device is arranged in a path along the direction of the pipe. 12. The fluid flow control device according to claim 1, wherein the fluid flow adjusting means is a pump that drives the flow of the fluid in the fluid flow conduit. 13. A flow sensor head mounted on a casing having a fluid flow conduit, a fluid flow adjusting means for regulating the flow of fluid in the fluid flow conduit, and an electric signal from the flow sensor head. Control means for calculating a flow rate value of the fluid in the fluid flow conduit based on the flow rate value, and controlling the fluid flow control means based on the flow rate value.The control means controls the fluid flow control means. After introducing a fluid into the fluid flow conduit to stop the flow of the fluid, a comparison is made between a threshold value and an electrical signal emitted from the flow rate sensor head and corresponding to the flow rate of the detected fluid. A fluid type control device for identifying which type of fluid in the fluid flow conduit is preset.