JPH01198560A - Detector for detecting pressure of pipe transport fluid and air bubble contained therein - Google Patents

Abstract

PURPOSE:To detect the injection pressure of a liquid and the air bubble mixedly transported by said liquid, by fixing a pair of a transmitting element and a receiving element both of which have contact surfaces each composed of a semicolumnar surface crossing a tube on both sides thereof in opposed relationship and inserting the tube between both elements in a grasped state. CONSTITUTION:The outer diameter D of a soft tube 10 is changed when the pressure of the fluid flowing through the tube 10 is varied but, since the interval L between transmitting and receiving elements 1, 2 is kept constant, the collapse quantity of the grasped part 11 of the tube 10 is varied and the contact area thereof is changed by a change in a curvature R2 and, at the same time, the contact force thereof is varied. Said change quantity and variation are developed as the change quantity of the electric signal output from the receiving element 2 of the ultrasonic wave transmitted from the transmitting element 1 and, therefore, when the output signal of a change quantity operator 6 is quantitatively analyzed, the pressure of the fluid can be continuously measured. When the air bubble mixed in the fluid in the tube 10 passes through the narrow part between the transmitting element 1 and the receiving element 2, the quantity of the ultrasonic wave reaching the receiving element 2 is extremely reduced. Therefore, when the output of the change quantity operator 6 is equal to or less than the set value of an output setting device 7, the signal of a sudden change part is detected from a comparator 8 to be capable of being obtained as an air bubble detection signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a technology for detecting transport fluids, and particularly to a pressure and bubble detector for pipe transport fluids using flexible tubes for medical use.

[Conventional technology]

Soft tube circuit configurations are generally used as a means of hygienically transporting blood and drug solutions in medical practice, but detecting and measuring air bubbles and injection pressure in blood and infusions sent to patients is important for patient safety management. It goes without saying that this must be done as a normal medical duty in terms of health and treatment information1.For this reason, conventional means for detecting the pressure and bubbles contained in pipe-transported fluids using this type of flexible tube have been developed. Various types are used as

[Problem to be solved by the invention]

However, with the conventional means for detecting the pressure of the fluid transported in the flexible tube and the air bubbles contained therein, it is difficult to detect air bubbles non-invasively using light or ultrasonic waves, and when trying to continuously measure the injection pressure, There were problems in terms of hygiene and economics, such as the need to form a branch circuit for pressure detection in a part of the tube or use a specially processed tube. .

The present invention has been made in view of the above problems, and is a pressure and bubble detector for pipe-transported fluid that can detect the injection pressure of liquid transported in a flexible tube and the air bubbles mixed and transported in the liquid. The purpose is to provide blood donations and blood transfusion procedures.

In various treatments such as artificial dialysis and blood purification, medical procedures such as drug administration, or general liquid transport management, there is no need to process the soft tube, and the injection pressure of the transport liquid and the air bubbles contained can be controlled at the same time. The purpose is to provide a means for continuous detection and measurement.

(Means for Solving the Problems) The pipe transportation fluid pressure and air bubble detector according to the present invention includes:
In an infusion circuit using a soft tube, a pair of transmitting elements and a receiving element each having a contact surface made of a semi-cylindrical surface intersecting the tube are fixed facing each other from both sides of the tube, and the tube is inserted between the two elements. The gist of this is to insert the tube in advance so as to appropriately narrow the passage.

Further, the transmitting surface of the transmitting element and the receiving surface of the receiving element, which are in pressure contact with the soft tube, are formed into a semi-cylindrical shape, and are configured to be orthogonal to the tube.

[Effect]

That is, the ultrasonic wave transmitted from the transmitting element is received by the receiving element, and the fluid transported through the tube can be managed by analyzing the received signal.

When the fluid pressure flowing through the soft tube changes, the outer diameter of the tube changes, so the amount of collapse (area) of the portion inserted into one pixel element increases or decreases. This variation in the amount of collapse appears as a variation in the amount of ultrasonic waves transmitted from the transmitting element reaching the receiving element, and therefore, the pressure of the fluid can be continuously detected by quantitative analysis of the output signal from the receiving element.

In addition, when air bubbles mixed into the fluid flowing in the tube pass through the narrow area between the transmitting element and the receiving element, some of the ultrasonic waves are diffused or absorbed by the air bubbles, resulting in less ultrasonic waves reaching the receiving element. The amount of sound waves becomes extremely small. Therefore, bubbles can be detected by analyzing sudden changes in the signal output from the receiving element.

【Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the pipe transport fluid pressure and air bubble detector according to the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes an ultrasonic transmitting element, and reference numeral 2 denotes an ultrasonic receiving element. The transmitting surface 3 and the receiving surface 4 of each pixel element 1 and 2 have a semi-cylindrical shape, and this curvature R1 is equal to the soft tube 10.
It is essential that the curvature R2 is sufficiently smaller than the curvature R2 formed by the collapsed portion 11 (see FIG. 3). The pixel element 1.2 is arranged so that the semi-cylindrical axes of the tube 10, the transmitting surface 3, and the receiving surface 4 are perpendicular to the tube 10, and the tube 10 has a preset outer diameter so that the passage narrows. A tube 10 is placed between the pixel elements 1 and 2, which are fixed facing each other with a narrow interval.
By inserting it.

As shown in FIG. 4, the ultrasonic signal of a constant frequency and constant intensity transmitted from the transmitting element 1 passes through the wall of the soft tube IO and the fluid to be inspected flowing inside the tube, and reaches the receiving element 2. The receiving element 2 converts the signal into an electrical signal and outputs the signal. Therefore, this electric signal is outputted when the initial value storage device 5 and the variable calculation device 6 which adjusts the difference between the initial value storage device 5 and the output of the variable calculation device 6 are equal to or less than the set value of the output setting device 7. This can be detected by a circuit configuration consisting of a comparator 8.

When the fluid pressure flowing inside the flexible tube 10 changes, the outer diameter of the tube 10 changes, but since the spacing between the pixel elements 1.2 is kept constant, the pixel elements 1.2 can be inserted into the flexible tube 1.2 as shown in FIG. The amount of collapse of the portion 11 that is flattened changes, and the contact area changes as the curvature R2 formed by the collapse portion 11 changes, and at the same time, the contact force changes. Variations in the contact area and contact force become elements that change the characteristics of the ultrasonic waves emitted from the transmitting element 1 reaching the receiving element 2, and appear as the range of the electrical signal output from the receiving element 2 (see Figure 6). ), the pressure of the fluid can be continuously measured by quantitatively analyzing the output signal of the variable calculator 6.

Furthermore, when air bubbles mixed into the fluid flowing inside the tube 10 pass through the narrow portion between the transmitting element 1 and the receiving element 2,
Since a part of the ultrasonic waves from the emitting 4P element 1 is diffused or absorbed and blocked by the bubbles, the amount of ultrasonic waves reaching the receiving element 2 is extremely reduced (arrow A in FIG. 6). Therefore, a comparison level Eo is manually set in the output setter 7 in advance, and when the output of the variable calculator 6 is less than the set value of the output setter 7, the signal of the sudden change part (arrow A) is detected from the comparator 8. This can be obtained as a bubble detection signal.

〔Effect of the invention〕

As described above, the pipe transport fluid pressure and bubble content detector according to the present invention is a sweeping structure in which a part of the soft tube is inserted between the ultrasonic transmitting/receiving elements, so the soft tube does not need to be processed in any way. The injection pressure gauge 3111 of the liquid that is continuously transported within the tube can detect air bubbles that are mixed into the liquid and transported. Therefore, not only general liquid transport management, but also blood donation and blood transfusion procedures 1 in particular.
It is extremely useful as a cover for various treatments such as artificial dialysis, blood purification, and infusion management for medical procedures such as drug administration.

The practical effects of the present invention are extremely large.

[Brief explanation of the drawing]

, FIG. 1 is a front view of the pipe-transported fluid pressure and bubble contained detector according to the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a main part showing the relationship between the transmitting/receiving element and the contact part of the tube. An enlarged view, FIG. 4 is a block diagram showing an example of the circuit, FIG. 5 is an explanatory diagram showing the relationship between fluid pressure and contact surface, and FIG. 6 is a diagram showing the relationship between the output signal of the receiving element and the output signal of the comparator. This is a timing chart. 1... Ultrasonic transmitting element 2... Ultrasonic receiving element 5
...Initial value storage device 6...Variable calculator 7...
Output setting device 8... Comparator 10... Soft tube ('' Agent: Patent attorney Takashi Hatakeyama (Tori)

Claims (2)

[Claims] (1) In an infusion circuit using a soft tube, a pair of transmitting element and receiving element each having a contact surface consisting of a semi-cylindrical surface intersecting with the tube are fixed facing each other from both sides of the tube, and the above is described between the two elements. The method is characterized in that the tube is inserted in advance so as to appropriately narrow the passage, the ultrasonic waves transmitted from the transmitting element are received by the receiving element, and the fluid transported in the tube is managed by analyzing the received signal. Detector for pressure and air bubbles in pipe transport fluids. (2) The pipe transport fluid pressure and bubble detector according to claim 1, wherein the transmitting surface of the transmitting element and the receiving surface of the receiving element that are in pressure contact with the soft tube are semi-cylindrical.