JPH02154739A - Automatic blood pressure measuring instrument - Google Patents

Abstract

PURPOSE:To always exactly measure blood pressures by providing a reference tank which is pressurized by a pressurizing means, such as a pump, and is reduced in pressure at a specified rate, a pressurizing zone which is pressurized by a pressurizing means, and a flow passage for discharge which discharges air through a pressure comparing section which is connected to the pressurizing zone and compares the pressure with the pressure in the reference tank. CONSTITUTION:The pump 1 is operated to supply the air into the reference tank 2. The air flows through a check valve 4 and through the flow passage into the pressurizing zone 5. The air in the tank 2 is discharged at the specified rate per unit time through a constant discharge valve 3 when the supply from the pump 1 is stopped after the pressure in the pressurizing zone 5 attains the prescribed value or above. The air in the tank 2 decreases at a specified ratio and the internal pressure thereof decreases at the specified rate as well. On the other hand, the air in the pressurizing zone 5 is discharged through an outflow path 8 as well. The pressure on the pressurizing zone 5 side is compared with the pressure in the tank 2 by a pressure comparing valve 10 at this time and the air is so discharged that both the pressures are equaled. The pressure in the pressurizing zone 5 decreases in the same manner as the pressure in the tank 2 and decreases at the specified rate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic blood pressure measuring device that enables stable pressure reduction.

[Prior Art] FIG. 2 is a configuration diagram of a simple blood pressure monitor. 21 is a pump driven by a small DC motor; 22 is a pressurization band such as a cuff that is wrapped around the arm and tightens the arm by introducing air pressurized by the pump 21 through a tube 23; and 24 is a pressure band inside the tube, that is, pressurization. Obi 2
2 is a pressure sensor that measures the air pressure; 25 is a constant discharge valve that always discharges a small amount of air in the tube; and 26 is a solenoid valve that is normally closed and that discharges the air in the tube in a short time after blood pressure measurement. This is a sudden haiben.

After the pump 21 is operated to supply a predetermined amount of high-pressure air to the pressurizing band 22 to stop pulsation, the pump 21 is stopped. Once the pump 21 stops, the air pressure will not increase any further, so
The air in the pipe is discharged through a constant discharge valve 25 in a constant small amount. Eventually, the pressure sensor 24 measures the systolic blood pressure. Thereafter, the air in the tube continues to be exhausted through the constant exhaust valve 25, and the pressure sensor 24 eventually measures the diastolic blood pressure. Thereafter, the quick exhaust valve 26 is operated to exhaust the air inside the pipe at once.

A constant discharge valve used in such a blood pressure monitor is shown, for example, in FIGS. 34 is a suction board which similarly has a chamber 35 on the upper surface of the center; 36 is a sealing body made of rubber with a diaphragm 37 formed in the center; 38 is a sealing body made of rubber and having a hole 39 in the center. A seal body 36 is sandwiched between the substrates 30 and 32, and a seal body 38 is sandwiched between the substrates 30 and 34, and these are assembled together with screws (not shown).

40 is a suction hole formed in communication with the chamber 35 for introducing pressurized air from the pump, 41 is an inflow path formed in the center of the substrate 30 and communicated with the chamber 31, and 42 is an inflow hole of the inflow path 41. Projections protruding into the chamber 31 are formed at four locations on the periphery at 90 degree intervals; 43 is an artificial part formed by recessing a portion of the periphery of the chamber 31 on the top surface of the substrate 30; 44 is a projection on the top surface of the substrate 30; The first small chamber 45 formed at the periphery is a narrow passage formed in the shape of a groove on the upper surface of the substrate 30 so as to communicate the entrance portion 43 and the small chamber 44 . In order to make this passage 45 long, it is arranged in a zigzag shape inwardly and outwardly using the entire surface, as shown in FIG.

47 is a second small chamber formed around the lower surface of the substrate 32;
Reference numeral 48 indicates a discharge passage formed vertically through the periphery of the substrate 32, and reference numeral 49 indicates a small chamber 47 and a discharge passage 48 on the lower surface of the substrate 32.
It is a narrow passage formed in the shape of a groove. This passage 49, like the passage 45, is formed long as shown in FIG.

50 is a screw hole formed in the center of the substrate 32 so as to communicate with the chamber 33. 51 is an adjustment screw screwed into the screw hole 50, and 52 is a concave portion of the adjustment screw 51.

Reference numeral 53 denotes a ventilation hole that is formed to penetrate from the recess 52 to the outside. A spring 54 has one end inserted into the recess 52 and the other end in contact with the diaphragm 37. Due to the elasticity of the spring 54, the diaphragm 37 is brought into contact with the protrusion 42 with a predetermined force. This force can be adjusted by turning the adjustment screw 51. The inside of the chamber 33 is maintained at atmospheric pressure by the ventilation holes 53.

The upper surface of the substrate 30 and the lower surface of the substrate 32 are separated by a seal member 36, and the chambers 31 and 33 are opposed to each other but separated by a diaphragm 37. Also, small room 4
4 and the small chamber 47 are also facing each other, but these are the seal body 36
It communicates through the hole 55. Six bodies 56 extend downward from the center of the diaphragm 37 and loosely penetrate into the inflow passage 41, and the tips of these six bodies 56 are thick (thus forming a valve part 57. 58 shown in Figure 5
．． Reference numeral 59 is a hole formed in the substrate 30, 32 for passing an assembly screw.

In such a configuration, when pressurized air is supplied from the pump to the suction hole 40, this air flows from the chamber 35 through the inflow path 41 and into the chamber 31 from between the protrusions 42. The air is further supplied to the inlet section 439 passageway 45. Small room 44. Hole 55.
The small chamber 471 is supplied to the discharge passage 48 through the passage 49. A small amount of air that has passed through these elongated passages is discharged from the exhaust passage 48. In the chamber 31, the air flowing out into the passage is replaced by the inlet passage 4.
The air pressure increases because there is more air entering the diaphragm 3.
7 is displaced to the chamber 33 side, and the inlet of the inflow path 41 is closed by the valve portion 57.

As a result, the pressure in the chamber 31 gradually decreases, so the diaphragm 37 is again displaced toward the chamber 31, the valve portion 57 moves away from the population, and the inflow path 41 opens.

In order to repeat such operations, the air pressure in the chamber 31 is controlled to be kept constant no matter what pressure of air is supplied from the pump. Therefore, a constant small amount of air is always discharged from the discharge passage 48.

[Problem to be Solved by the Invention 1] As described above, a blood pressure measuring device using a constant evacuation valve gradually reduces the pressure in the cuff at a constant rate by ejecting a small amount of air through constant defecation. This enables highly accurate measurements.

However, blood pressure measuring devices using this constant discharge valve reduce the pressure (therefore, depending on the thickness of the arm and the degree of winding of the cuff, even if the pressure of the cuff is the same, the amount of pressure that is fed into the cuff may vary). The amount of air in the cuff will be different. Therefore, if air is expelled at a constant rate, the rate of decompression will differ depending on the amount of air in the cuff. For example, if your arm is thick,
If the pressures are the same, the amount of air is large, the rate of pressure reduction is low, and measurement takes time. Conversely, if the arm is thin, the amount of air is small, so the decompression speed is high and the measurement time is shortened, but if the speed is too high, the measurement accuracy will deteriorate. For this reason, conventional blood pressure measurement devices are provided with an adjustment mechanism for reducing pressure at a constant rate.

However, adjustment is troublesome, and in practice it is often used without adjustment.

An object of the present invention is to provide an automatic blood pressure measuring device that can always reduce pressure at a constant rate without making the above-mentioned adjustments.

[Means for Solving the Problems] The blood pressure measuring device of the present invention includes a reference tank that is pressurized by a pressurizing means such as a pump and depressurized at a constant rate, and a pressure cuff that is pressurized by the pressurizing means. The system is equipped with a discharge passage connected to the pressurizing zone and exhausted through a pressure comparison section that compares the pressure in the reference tank with the pressure in the reference tank. The air supply is stopped, and the air in the pressurized band is discharged from the discharge flow path via the pressure comparison valve, and the systolic blood pressure and diastolic blood pressure are measured in this order while gradually reducing the pressure. When the pressure in the pressure band is reduced, the pressure in the reference tank is reduced at a constant rate, and as described above, the discharged air from the pressure band is compared with the reference tank in the pressure comparison section, and the pressure in the pressure band is determined as the standard. By discharging the tank so that it is equal to the pressure inside the tank, the pressure in the pressurized band is reduced at a constant rate, similar to the pressure reduction in the reference tank.

[Example] Next, an example of the blood pressure measuring device of the present invention will be described based on the drawings. In Fig. 1, 1 is a pressurizing part such as a pump, 2
3 is a reference tank having a predetermined capacity, and 3 is a constant discharge valve connected to the reference tank 2. For example, a structure as shown in FIGS. 3 to 5 described above is used. 5 is a pressure band connected to the basic tank 2 via a check valve 4 and an air inflow path 7. Reference numeral 10 designates a pressure comparison valve, which is composed of a base body 11 having a concave portion forming a chamber 14, another base body 12 having a concave portion forming a chamber 15, and a diaphragm 13 sandwiched between these base bodies 11 and 12.

An inlet 11 a is formed in one base 11 and connected to the reference tank 2 via a flow path 9 . Further, another inlet 12a is formed in the other base 12 and connected to the pressurizing band 5 via the flow path 8, and an exhaust port 16 is formed in the center. This pressure comparison valve lO allows the pressure in the chamber 14, that is, the pressure in the reference tank 2, to be adjusted to the pressure in the chamber 15, that is, the pressure in the pressurizing band 5.
, the diaphragm 13 blocks the exhaust port 16. Further, when the pressure in the chamber 14 becomes lower than the pressure in the chamber 15, the diaphragm 13 moves to the left in the drawing, and the air in the pressure band 5 is discharged. Therefore, when the pressure in the reference tank 2 decreases, the exhaust port 16 opens and the air in the pressurized band 5 is discharged, and the pressure decreases and becomes equal to the pressure in the reference tank 2. In this way, the pressure in the pressure band is always kept equal to the reference pressure, which is the pressure in the reference tank 2.

In the blood pressure measuring device having such a configuration, when the pump 1 is operated to supply air into the reference tank 2, air is further supplied from the reference tank 2 through the check valve 4 and into the pressurizing zone 5 through the flow passage. If the supply from the pump is stopped when the pressure in the pressure band 5 exceeds the desired value, the air in the reference tank 2 will be
A constant amount of air is discharged through the constant discharge valve 3 per unit time. As a result, the air inside the reference tank 2 decreases at a constant rate, and the pressure inside it also decreases at a constant rate.

On the other hand, the air within the pressurized zone is also discharged through the outflow passage 8. Here, as described above, the pressure on the pressurized band side is compared with the pressure in the reference tank by the pressure comparison valve lO, and the pressure is discharged so that the two become equal. The pressure in the pressurized band 5 therefore decreases in the same way as the pressure in the reference tank 2. Here, as described above, the pressure within the reference tank 2 decreases at a constant rate.

Therefore, the pressure in the pressure band also decreases at a constant rate. While the pressure of the cuff decreases at a constant rate, the systolic blood pressure and diastolic blood pressure are sequentially measured by the pressure sensor 6.

In the blood pressure measuring device of this embodiment, the rate of change in pressure in the reference tank is not affected by the thickness of the arm, etc. Therefore, the rate of pressure reduction, etc. is determined only by the air exhaust rate by the constant exhaust valve, and the desired constant rate is maintained. It is possible to keep it. Furthermore, the rate of pressure reduction in the pressure band is determined by the rate of decrease in pressure in the reference tank, and is therefore not affected by the amount of air in the pressure band.

For example, even if the amount of air in the pressure band is large, the amount of air discharged from the pressure band automatically increases and the pressure is always reduced in accordance with the rate of decrease of the pressure in the reference tank.

The check valve 4 used in this embodiment may not be used, and in this embodiment, air is supplied from the pump 1 to the reference tank 2 and further pressurizes the pressure band 5 through the inflow path 7. However, there is a method of pressurizing directly from pump 1, that is, pump 1.
The reference tank 2 and the pressure band 5 may each be pressurized directly. Furthermore, the reference tank and the pressurizing zone may be pressurized using separate pressurizing means. In any case, pressurization is stopped after the reference tank and pressure band are brought to approximately the same high pressure, and the pressure in the pressure band continues to decrease while remaining at the same pressure as the pressure in the reference tank.

[Effects of the Invention] In the blood pressure measuring device of the present invention, the pressure in the cuff is reduced at a pressure equal to the pressure in the reference tank, which is always reduced at a constant rate.
Regardless of the condition of the pressure cuff, such as the thickness of the subject's arm or the degree of wrapping of the cuff, measurements can always be made quickly and with high accuracy at the desired pressure reduction rate. .

[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of an embodiment of the blood pressure measuring device of the present invention, Figure 2 is a diagram showing the configuration of a conventional blood pressure monitor, and Figures 3 to 5 are constant discharge valves used in the blood pressure monitor. It is a figure showing an example. ■...Pump, 2...Reference tank, 3...Constant discharge valve.

Claims (1)

[Claims] a pressurizing section; a pressurizing band pressurized by air supplied from the pressurizing section and connected to an exhaust path for depressurizing;
A reference tank capable of continuously depressurizing at a constant speed, and a pressure comparison section disposed in the exhaust path and comparing the pressure of the pressurizing band with the pressure of the air in the reference tank, After pressurizing the pressure band and pressurizing the inside of the reference tank by the pressurizing section, the pressure of the pressure band is determined to be equal to the pressure inside the reference tank by the pressure comparison section of the exhaust gas from the pressure band. This automatic blood pressure measuring device is configured to continuously reduce the pressure in the cuff at a constant rate by evacuating the cuff so that the pressure in the cuff becomes constant, and to measure the systolic blood pressure and the diastolic blood pressure in this order during this pressure reduction.