JPH087109Y2 - Ambulance tube - Google Patents

Description

TECHNICAL FIELD The present invention relates to a structure of an elastic tube used in an elastic tube pump.

BACKGROUND ART As is well known, an elastic tube pump rotates a cylindrical side wall surface of a semi-cylindrical chamber and a shaft concentric with the semi-cylindrical chamber, which is bored in a flat casing made of a resin material such as polyvinyl chloride. In a pressing section formed by a pressing roller forming a movable surface with the cylindrical side wall surface of the main body composed of a pressing roller rotatably supported around an axis fixed on a concentric circle of a rotating disk By inserting the elastic tube and pressing the elastic tube with the pressing roller at least at two points to drive the rotary disk to rotate, the pressing roller rotates planetarily and continuously moves the elastic tube. . The infusion solution is pressure-fed in the moving direction by the pressing roller. Thus, the elastic tube is made of a soft vinyl chloride-based material, a silicon fluorine-based material, an olefin-based material having a soft, rubber-like elasticity and a restoring force. The reason is polyethylene, Teflon, etc.
In the case of a material that is hard but has a poor restoring force, the amount of infusion held between the pressing rollers at a certain point cannot be restored, and the amount of infusion held between the next pressing rollers cannot be restored. The first problem is that the area difference is small and the constant flow rate cannot be maintained. Looking at the fixed position of the tube, repeated bending stress is applied to the side of the cross section, resulting in early fatigue and rupture. This is because there is a second problem that it becomes unusable, whereas, on the other hand, a tube having a soft restoring property has a cross-section restoring force, does not change the infusion volume, and has a large fatigue resistance.

Problems of the Prior Art FIG. 3 is a view showing a pressed state of the elastic tube of the elastic tube pump in the above conventional example.
Is an elastic tube, and the elastic tube 1 is in the state shown in the drawing when pressed, but has a cylindrical cross section when not pressed. Reference numeral 2 is a casing, 21 is a cylindrical side wall, and the cylindrical side wall 21 is a side wall of a cylindrical chamber of the casing 2 and is a fixed surface. 3 is axis O
A pressing roller rotatably supported around -O 'holds the elastic tube 1 between the pressing roller 3 and the cylindrical side wall 21. When pressed, the elastic tube 1 has a perpendicular axis Y
The pressing force P acts on -Y. The pressing force P is the pressing roller 3
Although it is a constant value irrespective of the pressing position of the elastic tube 1, when viewed from the side of the elastic tube 1, the cross-section of the flow path is interrupted until the inner surfaces 12 come into contact with each other and the flow path is sealed, as shown in the figure, from the cylindrical cross section having a constant thickness. The area gradually decreases, and the pressing force P increases in inverse proportion to the flow passage cross-sectional area. That is, repetitive compressive stress is applied to the elastic tube 1 in proportion to the number of pressings of the pressing roller 3. Elastic tube 1
T ₂ | | tensile stress Yashirube direction in the elastic tube outer surface 11 when but being pressed, | T ₁ | is Yashirube direction compressive stress in the elastic tube inner surface _{12 | C 2 |, | C} 1 | is To work. When the elastic tube 1 is pressed as shown in the drawing, the elastic tube 1 has a frictional stress due to the elastic tube 1, the cylindrical side surface 21 and the pressing roller 3 added to the tensile stress of the outer surface 11, and the respective frictional stresses are not equal. T ₂ ≠ T ₁ . Compressive stress ｜
C ₂ | and | C ₁ | balance with the elastic reaction force of the elastic tube 1,
Since the compressive stresses | C ₂ | and | C ₁ | change according to the magnitude of the pressing force P, if the pressing force P is small, the compressive stresses | C ₁ |, | C ₂
| Is also small, and gap channels 13, 13 are formed at the sealing end of the inner surface 12 of the elastic tube 1, and leak is generated as a result of not being completely sealed, and therefore the infusion volume is small. Since the pushing force P must be increased in order to eliminate the gap flow paths 13 and 13, the tensile stresses | T ₁ | and | T ₂ | also increase, and the fatigue rate of the elastic tube 1 increases, resulting in early infusion failure. There was a problem of bringing.

Means for Solving Problems The present invention has been made to solve the above-mentioned problems of the conventional elastic tube. In the elastic tube cross section, a soft organic elastic material having a high elastic modulus from the inner peripheral surface to the outer peripheral surface is used. A highly reliable elastic tube that provides a structured elastic tube that increases the fatigue limit of the elastic tube and withstands long-term use because the inner peripheral surface sealing end is completely sealed even with a small pressing force without air passages. The purpose is to

Embodiment FIG. 1 (A) shows a cross section of an elastic tube 100 of the present invention, and the cross section is constant in the length direction. The material of the elastic tube 100 is the same as the conventional infusion tube in that it is a soft vinyl chloride type, silicon fluorine, olefin type, etc. and has rubber-like elasticity and a restoring force, but the conventional elastic tube 1 is all constant. Since it is made of a material, it has a constant elastic modulus, but the elastic tube 100 of the present invention shown in FIG. 1 (A) has a different elastic modulus from the center O toward the radial direction R. In the figure, R ₁ is the inner surface radius of the elastic tube 100, R ₂ is the outer surface radius, E ₁₀₁ and E
₁₀₂ represent elastic moduli corresponding to the inner peripheral surface radius R ₁ and the outer peripheral surface radius R ₂ , respectively, and the elastic moduli on the same radius are equal. FIG. 1 (B) shows a change in elastic modulus in the radial direction, which is small at the inner peripheral surface radius R ₁ and is large toward the outer peripheral surface radius R ₂ . In FIG. 1 (B), 1 shows a state in which the elastic modulus changes linearly from E ₁₀₁ to E ₁₀₂ from the radius R ₁ to R ₂ , and II is a little from the inner peripheral surface radius R ₁ side. The change in the radius causes a sharp change in the elastic modulus, and the radius of the outer peripheral surface R ₂
Although the change in the vicinity is small, III is the opposite of II, and the change in the elastic modulus is small in the vicinity of the inner peripheral surface radius R ₁ and suddenly increases as it approaches the outer peripheral surface radius R ₂ . I mentioned above,
The elastic moduli of II and III are small on the inner peripheral surface radius R ₁ side and are large on the outer peripheral surface radius R ₂ side, and the restoring force after the elastic tube 100 is pressed is in the large elastic modulus portion on the outer peripheral surface side. Given that the gap passage 13 has a small elastic modulus on the inner peripheral surface side, the elastic reaction force against the compressive force is also small, so that it can be removed with a small pressing force.

FIG. 2 (A) is an elastic tube 100 showing another embodiment.
In the cross-sectional view of the inner surface radius R ₁ to R ₁₂ , the low elastic modulus E ₁₁₁
Elastic material of uniform material, high elastic modulus E from radius R ₁₂ to R ₂
The elastic member _{112 is made} of a uniform material. FIG. 2 (B) shows a relationship of elastic moduli in the radial direction of the elastic tube 100, in which the low elastic portion 111 from the radius R ₁ to R ₁₂ is thin, and from the radius R ₁₂ to the radius R ₂ . High elasticity section 112
Is made thicker and the gap flow path 13 is sealed with a thin low-elasticity portion 111 without reducing the elastic restoring force so that the liquid can be effectively infused with a low pressing force. The elastic member is made of a different material.

Effect As is clear from the above description, when the conventional elastic tube is used when pressing the transfusion pressure, it is necessary to press the elastic tube so that there is no gap flow path. In the elastic tube of the present invention, the elastic modulus is small on the inner peripheral side, so that the elastic reaction force is small and therefore a small pressing force Since it is possible to eliminate the gap flow path, it is possible to provide an elastic tube having a high reliability because the fatigue limit of the elastic tube is large and the life is long.

[Brief description of drawings]

FIG. 1 (A) is a sectional view of the elastic tube of the present invention,
(B) is a diagram showing the relationship between the thickness in the radial direction of the elastic tube and the elastic modulus, and FIGS. 2 (A) and 2 (B) are diagrams for explaining another embodiment. It shows the same relationship as A) and (B). FIG. 3 is a diagram for explaining a force relationship when a conventional elastic tube is pressed. 1, 100 ... Elastic tube, 2 ... Casing, 3 ...
Pressing roller.

Claims (2)

[Scope of utility model registration request] 1. An elastic tube communicating with a liquid source, a pressing means for pressing the elastic tube between two points sandwiching at least one section to seal the liquid, and the pressing means on the elastic tube. In an infusion pump for injecting a liquid in a pressing movement direction, the elastic tube is made of a soft organic material having a high elastic modulus, and the elastic modulus of the soft organic material is set on the inner peripheral side of the elastic tube. An elastic tube characterized by having a small outer circumference. 2. In the cross section of the elastic tube, the inner peripheral side has a composite shape of low elastic material and the outer peripheral side is made of different elastic materials of high elastic material and each has a uniform thickness, and the inner peripheral low elastic layer is formed on the outer peripheral side. The elastic tube according to claim 1, wherein the elastic tube is thinner than the high elastic layer.