JPH04346044A - Pillow-type pressure sensor - Google Patents

Abstract

PURPOSE:To prevent generation of hysteresis at the time of sensing pressure by using a disposal and low-cost pillow-type pressure reaction tool and allowing it to be set and retained after setting without generating stress. CONSTITUTION:A load-cell type load sensor 25 is fixed to a base 28 through a thin-plate press member 37. Also, a lug portion of a pillow-type pressure- reaction tool 24 is held from both surfaces by a hold pin of the base 28 and a pin cap of a holder cover 29. Then, the base-side hold pin is supported elastically or the pressure reaction tool 24 is held simultaneously from both surface sides by a load transmission plate 40 and a press plate 45, thus enabling the pressure reaction tool 24 to be set while keeping a natural state properly. Namely, the pressure reaction tool 24 cannot be set while it is being distorted, thus preventing the hysteresis of a pressure detection value from occurring.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a pressure detector used in medical equipment such as blood processing equipment, which performs linear pressure detection using a pillow-type pressure reaction jig that has been used for a long time. be.

0002

[Prior Art] In medical equipment such as blood processing equipment,
Blood components such as blood cells and plasma that are taken out of the body are processed to remove unnecessary substances, and then returned to the body for circulation. Since these medical devices take blood directly from the patient's body and return it, it is important to prevent the device from affecting the patient's body. To this end, blood pressure taken, plasma pressure and plasma filtration pressure during the treatment process, return blood pressure, etc. must be controlled within predetermined ranges.

For example, in a conventional blood processing apparatus 1 shown in FIG. 12, blood sampled by a blood pump 2 is supplied to a blood filter 3 and separated into blood cell components and plasma. The separated plasma is passed through a plasma filter 5 by a plasma pump 4.
The harmful macromolecular components contained in the plasma are filtered out. The plasma is then discharged in a concentrated state by the plasma removal pump 6. At this time, an amount of replacement fluid 7 corresponding to the concentrated plasma discharged by the plasma removal pump 6 is replenished via the replacement fluid pump 8 as necessary. The plasma thus processed is mixed with previously separated blood cell components and then returned to the body via the bubble detector 9.

[0004]The blood processing apparatus 1 has the following features:
In the middle of the above-mentioned processing route, a blood pressure detector 10, a blood filtration pressure gauge 11, a plasma pressure gauge 12, and a plasma filtration pressure gauge 1 are installed.
A total of five pressure detectors, ie, pressure sensor 3 and return pressure dynamometer 14, are installed to detect the presence or absence of an abnormality. However, these conventional pressure detectors utilize a drip chamber 15, as shown in FIG. That is, the air chamber 16 formed in the upper part of the drip chamber 15 is connected to a strain gauge type pressure sensor 18 via a pressure tube 17.
A filter 19 is installed in the middle of the pressure guiding tube 17 to allow air to pass through but to block the passage of liquid. Furthermore, the air chamber 16 of the drip chamber 15 is
It is connected to a liquid inlet line 20 and an air vent line 21 . On the other hand, a liquid outlet pipe 22 is connected to the lower end of the drip chamber 15. The air vent line 21 is for positioning the liquid level in the drip chamber 15, and can be considered to be normally closed.

[0005] Pressure detection is performed using the drip chamber 1.
This is done by detecting the pressure in the air chamber 16 of No. 5 with a pressure sensor 18. In the conventional blood processing device 1,
In this way, the pressure detector using the drip chamber 15 can detect the blood sampling pressure, blood filtration pressure, plasma pressure, etc.
It is designed to detect plasma filtration pressure, return blood pressure, etc.

[0006]

[Problems to be Solved by the Invention] However, in the conventional pressure detector using the drip chamber 15, the liquid level in the drip chamber 15 also fluctuates as the pressure fluctuates, so it is difficult to absorb this fluctuation range. A volume greater than or equal to the capacity of the chamber must be stored in the chamber. For this reason,
There was a drawback that the priming volume had to be increased. Furthermore, before using the blood processing apparatus 1, it is necessary to adjust the air vent line 21 to adjust the height of the liquid level in the drip chamber 15. This is done in order to maintain the liquid level at the center of the liquid level fluctuation width of the drip chamber 15. In the conventional blood processing apparatus 1, such a drip chamber 15
It is necessary to set the liquid level height, and there are cases where 3 to 8 of these are provided in the entire device 1, which has the drawback of making the work extremely complicated. Further, setting the liquid level height requires skill, which is a cause of prolonging the preparation time.

On the other hand, in a pressure sensor using this drip chamber 15, an abnormal rise in the liquid level may occur in the drip chamber 15 for some reason, and the liquid may reach the filter 19. In the first place, the filter 19 is intended to protect the pressure sensor 18 from reaching the pressure sensor 18, but when it gets wet, air passage is blocked and the pressure sensor no longer functions as a pressure gauge. Therefore, malfunction of this measurement site has a serious effect on other parts, resulting in a failure of the entire blood processing device 1, which is a life-threatening problem in that the treatment is forced to be interrupted.

[0008]

[Means for Solving the Problems] The present invention improves and eliminates the above-mentioned conventional problems, and provides a pressure sensor that is low cost, disposable, and can accurately detect pressure fluctuations. The purpose is to provide equipment.

[0009]The first means adopted by the present invention to solve the above problem is to provide a substrate on which a load cell-type load sensor is installed on the front side, and to maintain a predetermined distance from the substrate. a flat load transmission plate and a flat holding plate disposed between the substrate and the holder cover; and a pillow type disposed between the load transmission plate and the holding plate. a pressure reaction jig, a pillow holding member that is attached to straddle the substrate and the holder cover and clamps a predetermined part of the pressure reaction jig, and the load transmission plate and the flat holding plate are rotated in conjunction with each other. This is a pillow-type pressure detector characterized by comprising a mechanism for moving the pressure sensor. The second means is a substrate on which a load cell-type load sensor is installed on the front side, a holder cover attached to the substrate to maintain a predetermined distance, and a holder cover disposed between the substrate and the holder cover. a flat load transmission plate and a flat holding plate; a pillow-shaped pressure reaction jig disposed between the load transmission plate and the holding plate; and a pillow-shaped pressure reaction jig installed across the substrate and the holder cover. The pillow-type pressure detector is characterized in that it is comprised of a pillow holding member that holds a predetermined portion of the pressure reaction jig, and a mechanism that elastically supports the pillow holding member on the substrate side. A third means includes a substrate having a load cell-type load sensor disposed on the front side, a thin plate pressing member that is coated on the front side of the load sensor and fixes it to the substrate, and the substrate. a holder cover attached to maintain a predetermined distance from the substrate; a flat load transmission plate and a flat holding plate disposed between the substrate and the holder cover; and between these load transmission and holding plates. 1. A pillow comprising a pillow-type pressure reaction jig disposed on the substrate, and a pillow holding member attached across the substrate and the holder cover and holding a predetermined portion of the pressure reaction jig. It is a type pressure detector.

0010

[Operation] A pillow-type pressure reaction jig can be manufactured at a lower cost than a drip chamber. In the present invention, this pressure reaction jig is arranged between the substrate on which the load cell type load sensor is installed and the holder cover. When the pressure reaction jig is set, the load transmission plate and the holding plate are interlocked to simultaneously hold the load sensor from both sides so that the pressure reaction jig is not distorted. In the second means, an elastic support mechanism for the pillow holding member is provided on the substrate side. Furthermore, in the third means, the load cell type load sensor is installed on the substrate via a thin plate pressing member so that the load cell type load sensor is not distorted. In short, distortion factors caused by the set of pressure sensing parts are eliminated, and as a result, detection accuracy is improved. Therefore, the pillow-type pressure reaction jig can react to the internal pressure without changing its posture, and can accurately transmit fluctuations in the internal pressure to the load cell-type load sensor.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained below based on the embodiments shown in the drawings. Figures 1 to 8 are
Pillow-type pressure detector 23 according to the first embodiment of the present invention
This shows that. As shown in the figure, in this embodiment, a pillow-type pressure reaction jig 24 and a load cell-type load sensor 25 are used as means for detecting the pressure of the pressure detector 23. The pillow-type pressure reaction jig 24 is formed by pressure molding an elastic material such as vinyl chloride into a bag shape, and its cross-sectional shape tends to change from an ellipse to a circle depending on the pressure. Also, the bag portion 2 of this pressure reaction jig 24
At the four corners of 4a, flat tab-like ears 26a to 26 are provided.
d is formed. On the other hand, the load cell type load sensor 25 utilizes a commercially available load cell. The mechanism is that strain occurs in the load cell depending on the load, which changes the internal resistance of the load cell.
The magnitude of the load is accurately detected by detecting changes in the electrical output of the load cell.

The pillow-type pressure sensor 23 of this embodiment has a mounting base 27 and an elastic structure on the front side of the mounting base 27 so as to be able to swing freely in the front-rear direction (vertical direction in FIG. 3). It has a supported substrate 28 and a holder cover 29 that is disposed opposite to the substrate 28 with a predetermined distance therebetween.

The mounting base 27 has a recess 30 formed on its bottom side, a protrusion 31 for locking the holder cover 29 erected on one end side, and a column 32 erected on the other end side. It is set up. On the base side of this support 32, the substrate 2
One end side of the holder cover 8 is swingably supported, and one end side of a holder cover 29 is swingably supported on the distal end side. Further, at the upper and lower ends of the front side of the mounting base 27, there are fluid inflow pipes 52 connected to the pillow-shaped pressure reaction jig 24.
Tube holders 54 and 55 for fitting and holding the outflow pipe 53 are provided. Furthermore, the mounting base 27
Hold pins 50a to 50d are erected at the center of the front side of the pillow-type pressure reaction jig 24 to be inserted into the small holes of the rectangular ears 26a to 26d.

The board 28 is disposed in the recess 30 of the mounting base 27 via a spring 33 so as to be able to swing back and forth, and the stopper 34 is normally attached to the convex part 35 of the mounting base 27.
It is pressed and biased to come into contact with. Further, a chamber 36 is bored in the center of the front side of the substrate 28. This chamber 36 is for installing a load cell type load sensor 25. The inner surface (especially the bottom surface) of the chamber 36 is finished with extremely high precision in order to prevent the load sensor 25 from wobbling or becoming unstable. On the front side of the load sensor 25 fitted into the chamber 36, there is a load sensor 2.
A pressing member 37 such as a stainless steel plate with a thickness of 0.1 mm is provided to prevent the substrate 28 from lifting up.
It is attached to the front side of the camera via screws 38 or the like.

A load transmission plate 40 is also swingably attached to the substrate 28 so as to come into contact with the sensing protrusion 39 of the load sensor 25. As shown in FIG. 4, the load transmission plate 40 has its proximal end pivotally attached to the pivot portion 41 of the base plate 28 via a pin 42, and is supported in a cantilever manner. Further, the front end side of the load transfer plate 40 is held by a presser plate spring 43 so as not to be far away from the substrate 28 and to maintain a constant position. Further, side walls 44, 44 are erected on both sides of the load transfer plate 40 of the substrate 28 in order to maintain a predetermined gap between the load transfer plate 40 and the pillow-type pressure reaction jig 24. This side wall 44,
44 is for guiding the installation of the pressure reaction jig 24, and can be omitted. Furthermore, the substrate 2
Hold pins 50a to 50d erected on the mounting base 27 are located around the load transmission plate 40 of No.8.
Through-holes 60a to 60d are provided for insertion.

On the other hand, the holder cover 29 has a flat pressing plate 45, which faces the load transmitting plate 40, attached to the surface on the substrate 28 side. The presser plate 45 is screwed into the holder cover 29 by means of an operating handle 46 attached to the front side of the holder cover 29 so as to move toward and away from the holder cover 29. Also, the holder cover 29
An opening/closing elastic pawl 47 that engages with the locking protrusion 31 of the mounting base 27 is attached to the side surface opposite to the pivot portion. Further, the substrate 28 and the holder cover 29 are
The respective arm portions of the mounting base 27 that are pivotally attached to the columns 32 are connected via rods 48 .

[0017] The load transmission plate 40 and the holding plate 4
5, the aforementioned pillow-type pressure reaction jig 24 is disposed. This pillow-type pressure reaction jig 24 is installed between both plates 40 and 45, and the small holes 49a to 49d (see FIG. 6) provided in the ears 26a to 26d are connected to the substrate 28. Hold pins 50a of the mounting base 27 inserted into the through holes 60a to 60d
50d to be inserted and supported. The hold pins 50a to 50d are attached to the holder cover 2.
It is adapted to be fitted and attached to the pin caps 51a to 51d of No.9. Therefore, these hold pins 50a
50d to 50d and pin caps 51a to 51d, the pressure reaction jig 24 is installed between the load transmission plate 40 and the holding plate 45, and the elastic pawl 47 for opening and closing is locked to the locking protrusion 31. In this state, the ears 26a to 26 of the pressure reaction jig 24
d is clamped and fixed, and functions as a pillow holding member.

Next, the usage of the pillow type pressure detector 23 constructed as described above will be explained. First, a pillow-type pressure reaction jig 24 is set. This setting is performed with the holder cover 29 open as shown in FIGS. 1 and 5. This holder cover 29 is connected to the substrate 28 via a rod 48. Therefore, the substrate 28 is
In the open state, the holder cover 29 is pushed down and retreated toward the bottom of the recess 30 of the mounting base 27 against the biasing force of the spring 33, as shown by the chain line in FIG.

By the way, in this embodiment, the set of the pressure reaction jig 24 includes a hold pin that protrudes through the substrate 28 in the space between the retreated substrate 28 and the opened holder cover 29. This is done by inserting the small holes 49a to 49d of the ears 26a to 26d of the pressure reaction jig 24 into the holes 50a to 50d. In addition, the tube holders 54 and 55 of the mounting base 27 are provided with an inflow pipe 52 of the pressure reaction jig 24.
and 53 are fitted and held. In this case, the hold pins 50a to 50d and the tube holder 54,
55 are on the same plane, the inflow pipe 52 and the outflow pipe 5
3 can be formed in a straight line so as not to bend with respect to the bag portion 24a.

[0020] Also, at the time of this setting, the load transmission plate 4
As shown by the chain line in FIG.
, the bag portion 24a of the pressure reaction jig 24 and the load transmission plate 40 never come into direct contact with each other. When the board 28 is fixed to the mounting base 27, this is because the ears 26a to 2 of the pressure reaction jig 24
6d to open the small holes 49a to 49d.
This is to prevent the bag portion 24a from contacting the load transmission plate 40 and being set while being deformed when it is fitted into the pin caps 51a to 51d. Note that the position of the pressure reaction jig 24 at the start of this set is the same position as when the set is completed, as shown by the solid line in FIG. 3, and the pressure reaction jig 24 moves freely until the set is completed. There is no difference.

To explain this in more detail, for example, when the pressure detector 23 of this embodiment is incorporated into an assembly in which the blood processing apparatus 1 is incorporated into one board as shown in FIG. , the mounting base 27
is attached and fixed to the board of the blood processing device 1, so various piping such as the blood pump 2 and filter 3 that are attached to the board, and the inflow pipe 52 and outflow pipe 5 of the pressure reaction jig 24 are attached.
3 and the bag portion 24a can be arranged in the same plane. Therefore, the inflow pipe 52 and the outflow pipe 53 will not be bent when replacing the pressure reaction jig 24, etc., and the life of the piping in this portion can be extended.

After the pressure reaction jig 24 is set in this manner, the holder cover 29 is rotated from the state shown by the chain line in FIG. It is fitted and locked into the locking protrusion 31. In other words,
Close the holder cover 29. This allows rod 4
8, the substrate 28 is rotated and returned to the position shown by the solid line in FIG. This closing operation of the holder cover 29,
Due to the rotation return operation of the substrate 28, the hold pins 50a to 50d inserted into the small holes 49a to 49d of the ears 26a to 26d of the pressure reaction jig 24 are fitted with the pin caps 51a to 51d of the holder cover 29. The ears 26a to 26d to 2 of the pressure reaction jig 24
6d is now held between both sides. Further, as the holder cover 29 closes, the load transmission plate 40 attached to the base plate 28 and the pressing plate 45 of the holder cover 29 simultaneously clamp the bag portion 24a of the pressure reaction jig 24 from both sides. Therefore, there is no possibility that these members 40 and 45 and the bag portion 24a are set in a twisted state.

[0023] This completes the setting of the pressure reaction jig 24. In this state, the magnitude of the output value of the load sensor 25 varies depending on the set state of the pressure reaction jig 24 used. Therefore, the load sensor 25
It is necessary to calibrate the detected values output from the That is,
It is necessary to set the "initial value" of the load sensor 25. This setting can be made by adjusting the operating handle 46 attached to the holder cover 29 and moving the presser plate 45 to the holder cover 29.
Do this by approaching or separating from 9. As a result, the compression state of the bag portion 24a of the pressure reaction jig 24 is changed, and the force pressing the load sensor 25 through the load transmission plate 40 is changed. Therefore, the magnitude (initial value) of the signal output from the load sensor 25 is set in a non-use state in which no fluid flows into the pressure reaction jig 24. By setting this initial value, pressure reaction jig 2
The slope of the output signal characteristic curve of 4 is determined.

After setting the initial value of the load sensor 25 in this way, the fluid to be actually measured is
It is sufficient to pass from the inflow pipe 52 to the pressure reaction jig 24 and the outflow pipe 53. Thereby, in the load sensor 25, the load cell reacts according to the pressure of the fluid passing through the pressure reaction jig 24, and the pressure of the fluid is continuously detected. Of course, the output signal value from the load sensor 25 is
It goes without saying that this is automatically calculated by a built-in computer based on the slope of the characteristic curve for which the initial value has been set, and is displayed as the detected pressure of the fluid.

[0025] Therefore, this pillow type pressure detector 23 is
When applied to the blood processing apparatus 1 shown in FIG. 12, lower and upper limits such as blood sampling pressure, hemofiltration pressure, plasma pressure, plasma filtration pressure, return blood pressure, etc., and intermediate values from the lower limit to the upper limit are It is capable of continuous and accurate detection and has excellent functionality for controlling medical equipment. Further, it can be set in the conventional blood processing apparatus 1 very easily and in a short time, and the preparation time can be significantly shortened. Furthermore, unlike the conventional drip chamber 15 shown in FIG. 13, the filter 19 does not get wet, which may cause malfunction or interrupt treatment.

In this case, when the patient is changed, the disposable blood circuit newly installed in the blood processing device 1 is cleaned and primed, but the pillow-shaped pressure response included in the disposable blood circuit is cleaned and primed. Since the jig 24 is also new, the initial value of the load sensor 25 may be reset accordingly. Of course, the preparation is extremely simple since it only requires adjusting the operating handle 46. Moreover, the pressure reaction jig 24 has been widely used as a limit switch that detects only the upper or lower limit of pressure.

By the way, the proven pressure reaction jig 2
4, if this is simply used in combination with the load sensor 25, the bag portion 24a of the pressure reaction jig 24 will deform into an odd shape, making it impossible to accurately detect pressure. In this embodiment, the pressure reaction jig 24 is held in the following manner so that fluid pressure can be continuously and accurately detected.

First, the pressure reaction jig 24 and the load sensor 25 are set in such a way that no distortion occurs. Regarding the load sensor 25, the inner surface of the chamber 36 of the substrate 28 is finished with high precision, and the load sensor 25 is set so as not to wobble. Further, a thin plate pressing member 37 is provided to prevent the load sensor 25 from jumping out of the chamber 36 when the pressure reaction jig 24 is replaced. Regarding the pressure reaction jig 24, a predetermined gap is formed between the side walls 44, 44 so that when the bag portion 24a senses the pressure and expands, it abuts against the side walls 44, 44 and does not have an irregular shape. has been established. This is because if the bag portion 24a comes into contact with the side walls 44 and becomes distorted, the pressure acting on the bag portion 24a will be biased and will not be accurately transmitted to the load transmission plate 40. Regarding the pressure reaction jig 24, as described above, in order to prevent the pressure reaction jig 24 from being set in a deformed state when setting it, the substrate 28 and the holder cover 29 are opened and closed in conjunction with each other, and both sides of the pressure reaction jig 24 are I try to hold this at the same time.

Furthermore, in this pressure detector 23, by using a special jig to hold the pressure reaction jig 24 after setting it, stable pressure detection can be performed without causing distortion. That's what I do. One of them is to use the pressure reaction jig 24 using the substrate 28 and holder cover 29 described above.
The ear portions 26a to 26d of the bag portion 24a are fixed so that the bag portion 24a does not deform into an irregular shape in response to fluid pressure, and undergoes stable expansion changes. Another method is to transmit the expansion due to the fluid pressure of the bag portion 24a to the load sensor 25 via the load transmission plate 40, and to pivotally support the base end of the load transmission plate 40 with a pin 42. This prevents the load transmission plate 40 from twisting and enables accurate load transmission.

FIG. 9 shows the results of an experiment in which fluid pressure was actually detected using the pillow-type pressure detector 23 according to the first embodiment of the present invention. This experiment was conducted by changing the distance between the holder cover 29 and the holding plate 45 and changing the initial value setting three times. In each case, the fluid pressure was gradually increased, and then the fluid pressure was sequentially decreased to the original pressure, which was performed as one cycle. Thereby, it is possible to detect hysteresis of the pressure detector 23. According to the experimental results shown in FIG. 9, in either case, the value detected by the load cell-type load sensor 25 changes in a quadratic curve with respect to changes in fluid pressure, causing systeresis. Accurate pressure detection is performed without any trouble. In addition, by adjusting the operation handle 46 and changing the distance between the holder cover 29 and the holding plate 45, the initial value of the load sensor 25 can be changed, and the load sensor 2
It is possible to determine the slope of the output signal characteristic curve of 5.

For reference, FIG. 10 shows a set of load sensor 25 and pressure reaction jig 24 intentionally
These are the fluid pressure detection results when the test was performed in a twisted state. As is clear from these results, in each case, the trajectory when the pressure is increased is different from the trajectory when the pressure is decreased, resulting in so-called hysteresis. From this, it is clear how important it is to set the load sensor 25 and pressure reaction jig 24 in the correct posture.

FIG. 11 shows a pillow-type pressure detector 56 according to a second embodiment of the present invention. In this embodiment, hold pins 58a to 58d on the substrate 57 side that sandwich the ears 26a to 26d of the pressure reaction jig 24 are elastically supported by springs 59 within the substrate 57. The board 57 is fixed, and the holder cover 29
is pivotally connected at one end to this substrate 57, and can be opened and closed freely. In this case, the pressure reaction jig 24 may be set by closing the holder cover 29 with the pressure reaction jig 24 placed on the hold pins 58a to 58d. In this case as well, the ears 26a to 26 of the pressure reaction jig 24
d can be set in its natural posture without pulling, so hysteresis does not occur in pressure detection. Other configurations and effects are basically the first
This is the same as in the embodiment.

By the way, the present invention is not limited to the above-described embodiments, and for example, the shapes and sizes of the substrates 28, 57 and the holder cover 29, as well as the pressure reaction jig 24
The shape, number, etc. of the ears 26a to 26d can be changed as appropriate. Furthermore, other clamping means such as clips and clamps may be used as the means for clamping and fixing the ears 26a to 26d. Furthermore, this pressure detector 2
3 can also be applied to medical equipment other than the blood processing apparatus 1 and other equipment that detects fluid pressure.

[0034]

[Effects of the Invention] As explained above, in the present invention,
By combining an inexpensive pillow-type pressure reaction jig with a proven track record and a load cell-type load sensor using a special holder mechanism, we provide an inexpensive pressure detector that is highly accurate, reliable, and disposable. be able to. Therefore, when this pressure detector is used in medical equipment such as blood processing equipment, the preparation time can be significantly reduced compared to conventional methods, and failures and malfunctions are less likely to occur.
There are no problems such as being forced to interrupt treatment. Furthermore,
The load cell type load sensor and the pressure reaction jig can be set and held in the correct posture so that no distortion occurs, and hysteresis does not occur in the detected pressure value.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a state in which a pressure detector holder cover of a first embodiment of the present invention is opened.

FIG. 2 is a perspective view of a pressure detector according to a first embodiment of the present invention.

FIG. 3 is a plan view of a pressure detector according to a first embodiment of the present invention.

FIG. 4 is a perspective view of a substrate according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing the mounting base and holder cover of the first embodiment of the present invention.

FIG. 6 is a front view showing a substrate and a pressure reaction jig according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional plane of the substrate of the first embodiment of the present invention.

FIG. 8 is a partial front view of the substrate of the first embodiment of the present invention.

FIG. 9 is a drawing showing measurement results of the pressure detector of the first embodiment of the present invention.

FIG. 10 is a diagram showing hysteresis of a pressure sensor.

FIG. 11 is a partially sectional plan view of a pressure detector according to a second embodiment of the present invention.

FIG. 12 is an overall block diagram of a conventional blood processing device.

FIG. 13 is a front view of a drip chamber of a conventional blood processing device.

[Explanation of symbols]

23...Pressure detector 24...Pressure reaction jig 25...Load sensor 28...Substrate 29...Holder cover 33...Spring 36...Chamber 37...Thin plate pressing member 40...Load transmission plate 45...pressing plate 48...Rod 56...Pressure detector 57...Substrate

Claims (3)

[Claims] 1. A substrate having a load cell-type load sensor installed on the front side, a holder cover attached to the substrate to maintain a predetermined distance, and a holder cover disposed between the substrate and the holder cover. a flat load transfer plate and a flat presser plate; a pillow-type pressure reaction jig disposed between the load transfer plate and the presser plate; A pillow-type pressure detector comprising a pillow holding member that holds a predetermined portion of a pressure reaction jig, and a mechanism that rotates the load transmission plate and the flat holding plate in conjunction with each other. 2. A substrate on which a load cell-type load sensor is installed on the front side, a holder cover attached to the substrate to maintain a predetermined distance, and a holder cover disposed between the substrate and the holder cover. a flat load transfer plate and a flat presser plate; a pillow-type pressure reaction jig disposed between the load transfer plate and the presser plate; A pillow-type pressure detector comprising a pillow holding member that holds a predetermined portion of a pressure reaction jig, and a mechanism that elastically supports the pillow holding member on the substrate side. 3. A substrate comprising a load cell-type load sensor disposed on the front side, a thin plate pressing member that is coated on the front side of the load sensor and fixes it to the substrate, and a pressing member that is attached to the substrate. a holder cover attached to maintain a predetermined distance from the base plate, a flat load transmission plate and a flat holding plate disposed between the substrate and the holder cover, and a space between the load transmission plate and the holding plate. 1. A pillow comprising a pillow-type pressure reaction jig disposed on the substrate, and a pillow holding member attached across the substrate and the holder cover and holding a predetermined portion of the pressure reaction jig. Type pressure detector.