| 主权项 |
1. A device for dispensing fluid to a patient and indicating a flow condition of the fluid through the device, the device comprising:
a fluid reservoir configured to provide a source of fluid under pressure; a continuous flow path from the source providing a continuous and substantially constant flow rate of the fluid under pressure, the continuous flow path in fluid communication with the source of fluid and a catheter for delivery of the fluid to the patient; a flow regulator included in the continuous flow path, the flow regulator setting the flow rate of the fluid through the continuous flow path from the source of fluid to the patient; and at least one pre-biased indicator in fluid communication with the continuous flow path, the at least one pre-biased indicator configured to provide a discrete visual signal that the pressure of the fluid in the continuous flow path is different from a predetermined level of pressure, thereby indicating a fluid flow condition, wherein the at least one pre-biased indicator comprises:
a housing having a first end, a second end, one or more walls defining an interior channel, and an axial dimension, the first end of the housing being in fluid communication with the continuous flow path, and at least a portion of the housing being transparent or translucent;a flexible sleeve positioned within the interior channel of the housing, the flexible sleeve comprising: a first surface, an opposed second surface, a first end located within the interior channel of the housing near the first end of the housing and in fluid communication with the continuous flow path, a second end sealingly engaged with the housing, and a flexible, generally annular portion joining the first end and second end of the sleeve, the annular portion defining a rolling annular fold intermediate the first end and the second end such that at least a portion of the first surface of the flexible sleeve is generally adjacent the one or more housing walls and at least a portion of the second surface of the flexible sleeve defines a sleeve cavity; anda biasing element located at least partially within the sleeve cavity and between the first end of the housing and the second end of the housing, the biasing element being configured to deform at a predetermined pressure so the first end of the flexible sleeve moves from a first axial position to at least a second axial position to provide a discrete visual signal that the pressure of a fluid in the continuous flow path is different from the redetermined level of pressure,wherein the movement of the flexible sleeve in an axial direction causes a portion of the second surface of the flexible sleeve to evert at the rolling annular fold so that it becomes directly adjacent the one or more housing walls. |
