a. Field of the Invention
The field of the invention pertains to manifolds for splitting a fluid flow, more specifically, manifolds that uniformly split fluid from an inlet passage among a multiplicity of outlet passages.
b. Background Art
Splitting a quantity of fluid into equal portions is useful for many reasons. For example, a sample of fluid may be evenly distributed among the wells of a microtitration plate ("plate" or "microplate") or among a group of test tubes. In this manner, research may be conducted on several uniform samples at the same time, accelerating the research and allowing for direct correlation of results.
One existing method used to split a quantity of fluid into approximately equal portions involves dedicating a costly pump or syringe to each outlet passage. A common and less expensive method used for dispensing fluid into a microplate entails passing the fluid through a manifold. The instant invention relates to this latter method.
Customarily, a manifold comprises multiple ports or passages inserted into an elongated cylindrical cavity. Fluid is introduced into the cavity and subsequently dispersed through outlet ports into a receptacle (e.g., a microplate). A manifold with only two symmetrically placed outlet passages would have a nearly equal flow from its outlet passages. However, manifolds with more than two outlet passages are the most useful, and the more outlet passages, the greater the flow disparity.
In a typical manifold, the number of outlet passages is designed to match the number of wells in a single column of a microplate, which has several columns of wells. In this manner, the manifold may fill the microplate one column at a time. Thus, Manifolds having either eight or twelve outlet passages are common. The outlet passages are positioned, not necessarily symmetrically, on each side of the inlet passage. Accordingly, the flow from each of the outlet passages is not uniform in the absence of a flow modifying device such as the instant invention.
In the operation of a typical manifold for microplate dispersion applications, the manifold is first primed to eliminate the manifold's "dead volume" (i.e., the volume of fluid needed to fill the manifold before useful dispensing can start). Then, a volume of fluid equal to the volume desired for each well in a single column of the microplate times the number of outlet passages (which equals the number of wells in a single column of wells), is dispensed into the inlet passage of the manifold. Ideally, the manifold then evenly disperses the flow among the microplate wells of the column. However, the flow from the outlet passages nearest the inlet passage is typically less than the flow from the outlet passages most distant from the inlet passage. This discrepant flow pattern results from the internal flow dynamics of the manifold, which must be adjusted to balance the flow.