Fluid metering device

摘要

A method and apparatus for metering fluids that are parenterally administered to a patient. The fluid metering device consists of a plastic housing having a primary fluid channel formed therein that is in fluid communication with a fluid source. A secondary fluid channel is also formed in the housing and is connected at one end to the primary fluid channel so as to be in fluid communication therewith. Fluid flows through the primary fluid channel and through a fixed resistor that is in series with the primary fluid channel. The fluid then flows through a drip tube in series with the fixed resistor. From the drip tube, the fluid is collected in a drip chamber. The secondary fluid channel is vented into the drip chamber so that the pressure at the open end of the stationary fluid channel will be the same as the pressure in the drip chamber. Thus, the fixed resistor will cause the fluid to back up, entering the secondary fluid channel. Because the pressure in the secondary fluid channel is the same as the pressure in the drip chamber, the level of fluid in the secondary fluid channel will be proportional to the rate of fluid flow. The rate of fluid flow through the primary fluid channel may therefore be read directly from the level of fluid in the secondary fluid channel.