Fluid flow detector

1. A fluid flow detector for detecting the flow of a fluid in a transfusion line, comprising:

a detector main body defining a fluid flow channel having a circular cross section and comprising, an upstream hole formed at an upstream end of the detector main body, a downstream hole formed at a downstream end of the detector main body, a fluid flow detection channel positioned adjacent the upstream hole, a discharge channel positioned adjacent the downstream hole, and an intermediate flow channel provided between the fluid flow detection channel and the discharge channel; and

a mobile body positioned within the fluid flow channel and dimensioned to be movable along the fluid flow channel in response to the flow of a fluid inside the fluid flow channel, and in which an outer peripheral edge part of a face of the fluid flow channel which is orthogonal to the direction of movement is formed to be circular;

wherein the diameter of the fluid flow detection channel is smaller than the diameter of the discharge channel, and the maximum diameter of the outer peripheral edge part of the face of the fluid flow channel orthogonal to the direction of movement of the mobile body is set to be slightly smaller than the diameter of the fluid flow detection channel, and the upstream hole and the downstream hole are formed with a size and shape such that fluid can flow around the mobile body through the upstream and downstream holes;

wherein the intermediate flow channel has a diameter that becomes steadily greater from the fluid flow detection channel towards the discharge channel;

wherein the intermediate flow channel has a length in a longitudinal direction that is smaller than the diameter of the outer peripheral edge part of the mobile body; and

wherein the fluid flow detection channel, the discharge channel, and the intermediate flow channel, are arranged in a straight line.

2. A fluid flow detector according to claim 1 , in which the mobile body consists of a spherical body.

3. A fluid flow detector according to claim 1 , wherein the fluid flow channel from between the upstream hole and the downstream hole consists of a shape in which the peripheral edge part of the upstream hole and downstream hole orthogonal to the flow of fluid is elliptical.

4. A fluid flow detector according to claim 1 , in which an inflow pipe comprising a female luer which links in communication with the fluid flow channel is joined to the upstream hole of the detector main body, and an outflow pipe comprising a male luer which links in communication with the fluid flow channel is joined to the downstream hole of the detector main body.

5. A fluid flow detector according to claim 1 , wherein the fluid flow detector is incorporated into a transfusion line that includes a fluid supply part and a fluid supply channel through which passes a fluid supplied from the fluid supply part, and the fluid flow detector is arranged in the fluid supply channel.

6. A fluid flow detector, comprising:

a detector main body defining a fluid flow channel having an upstream end and an downstream end, the fluid flow channel defining a fluid flow detection channel disposed on the upstream end, a discharge channel disposed on the downstream end, and an intermediate flow channel provided between the fluid flow detection channel and the discharge channel; and

a mobile body movably disposed within the fluid flow channel between the fluid flow detection and discharge channels, wherein the discharge channel has a diameter larger than the fluid flow detection channel, and wherein the mobile body is configured to be selectively positioned within the fluid flow detection channel to provide indicia of fluid flow within the fluid flow detection channel;

wherein the intermediate flow channel has a diameter that becomes steadily greater from the fluid flow detection channel towards the discharge channel;

wherein the intermediate flow channel has a length in a longitudinal direction that is smaller than the diameter of the outer peripheral edge part of the mobile body; and

wherein the fluid flow detection channel, the discharge channel, and the intermediate flow channel, are arranged in a straight line.

7. A fluid flow detector according to claim 6 , wherein the mobile body is positioned to move towards the discharge channel in response to gravitational force acting on the mobile body when the detector main body is disposed in an initial position.

8. A fluid flow detector according to claim 6 , wherein the diameter of the fluid flow detection channel is slightly larger than the diameter of the mobile body so that fluid may flow past the mobile body within the fluid flow detection channel.

9. A fluid flow detector according to claim 6 , wherein the mobile body is shaped and dimensioned to enable fluid to flow through the fluid flow channel at a predetermined minimum flow rate.

10. A fluid flow detector according to claim 6 , wherein the mobile body is spherically shaped.

11. A fluid flow detector according to claim 6 , wherein the fluid flow channel is dimensioned to accommodate a predetermined minimum flow rate of between about 0.1 ml/hr and about 20 ml/hr.

12. A fluid flow detector according to claim 6 , wherein at least one of the fluid flow detection and discharge channels of the fluid flow channel is configured to be visually perceptible to a user.

13. A fluid flow detector according to claim 6 , wherein the fluid flow channel is configured to receive a drug solution for passage to a patient's body.

14. A fluid flow detector according to claim 6 , wherein at least one of the upstream end and the downstream end of the fluid flow channel is configured to engage a medical device.