Patent Description:
This application is directed to a flow-regulating arrangement, particularly suited for use in an automated peritoneal dialysis system.

In an automated peritoneal dialysis system as disclosed, for example, in <CIT>, there are a pair (at least) of fluid distribution manifolds. Each of the manifolds has an elongated configuration and two or more ports that permit fluid to flow into or out of a central chamber that runs the length of the manifold, and tubing through which various treatment fluids flow is connected to the various ports. One length of tubing extends from an outlet port of one manifold to an inlet port of the other manifold, passing through a peristaltic pump that drives fluid between the manifolds and hence throughout the various fluid-flow lines of tubing. This is illustrated, for example, in Figures 7A - 7D and Figures 8A and 8D of <CIT> and the accompanying text.

Furthermore, <CIT> illustrates in Figure 8D an arrangement in which the manifolds and peristaltic pump are housed within a clamshell-type cassette case, and the various lines of tubing leading to and from the manifolds pass across openings formed in the halves of the cassette case. As further explained in the patent, flow through the various lines of tubing may be permitted or prevented by means of a linear actuator (solenoid clamp, stepper and screw drive, pinching mechanism like a plier grip, or other kind of mechanism) that is able to access and selectively clamp each of the various lines of tubing through its respective opening. From <CIT> a medical fluid injection system with an automated valve manifold is known, which comprises several cylindrical flow-directors, each of the flow-directing units having a shaped, rotary insert that rotates within a chamber to control a flow direction.

Because the fluid distribution assembly is to be used for medical treatment, it is important that flow through the various lines of tubing be controlled (i.e., permitted or prevented) with assurance. Additionally, as a medical device that is intended to be disposed of, cost of manufacture is a consideration.

Objects and advantages of embodiments of the disclosed subject matter will become apparent from the following description when considered in conjunction with the accompanying drawings.

Embodiments will hereinafter be described in detail below with reference to the accompanying drawings, wherein like reference numerals represent like elements. The accompanying drawings have not necessarily been drawn to scale. Where applicable, some features may not be illustrated to assist in the description of underlying features.

A flow-regulating system <NUM> in accordance with the disclosed subject matter is illustrated in <FIG>, <FIG>, and <FIG>. The system utilizes a disposable porting cassette <NUM>, which includes a pair of disc-shaped, rotary flow-directing units 104a, 104b that are housed within a clamshell-type cassette casing having side parts 106a and 106b.

As shown in <FIG>, multiple incoming-fluid delivery tubes 108a-108f, made from medical-grade material, are attached to respective tube-attachment fittings 110a-110f projecting from the flow-directing unit 104a, and multiple outgoing-fluid delivery tubes 112a-112f, also made from medical-grade material, are attached to respective tube-attachment fittings 114a-114f projecting from the flow-directing unit 104b. Additionally, a pumping tube segment <NUM> extends between the flow-directing units 104a and 104b, attached respectively to tube-attachment fitting <NUM> projecting from the flow-directing unit 104a and tube-attachment fitting <NUM> projecting from the flow-directing unit 104b. The pumping tube segment <NUM> passes through a peristaltic pump <NUM>, which can drive fluid in either direction through the pumping tube segment <NUM> depending on the direction of rotation of the peristaltic pump's actuator (not shown). The incoming-fluid delivery tubes 108a-108f may be attached to the tube-attachment fittings 110a-110f and outgoing-fluid delivery tubes 112a-112f may be attached to respective tube-attachment fittings 114a-114f by bonding or other suitable means known in the art.

Construction of the rotary flow-directing unit 104a (e.g., with tube-attachment fittings arranged as illustrated for the flow-directing unit 104a in <FIG>) is illustrated in <FIG>. The flow-directing unit 104b is similarly configured except for being a mirror image of the flow-directing unit 104a. The flow-directing unit 104a includes a generally circular, pan-shaped porting housing <NUM> and a disc-shaped, flow-controlling insert member <NUM> that fits into the porting housing <NUM>. Both components <NUM> and <NUM> may be made from medical-grade plastic or other suitable materials.

The porting housing <NUM> has a circular bottom wall <NUM> and a ring-shaped sidewall <NUM>, with an open top. As best shown in <FIG>, tube attachment fittings <NUM> (corresponding to the attachment fittings 110a-110f in <FIG>) are integrally formed with and extend outwardly from the sidewall <NUM>, as does tube attachment fitting <NUM>. The tube attachment fittings <NUM>, <NUM> are hollow and cylindrical, with open outer ends <NUM>, <NUM>, respectively, and are open to the interior of the porting housing <NUM> via apertures <NUM>, <NUM>, respectively. The tube attachment fittings <NUM>, <NUM> may have features (not illustrated) such as hose barbs, luer locks, etc., to secure the various tubes to the tube attachment fittings <NUM>, <NUM>. As best illustrated in <FIG>, the tube attachment fittings <NUM> and corresponding apertures <NUM> are offset in the axial direction relative to the tube attachment fitting <NUM> and aperture <NUM>, with the apertures <NUM> being located closer to the open top of the sidewall <NUM> and the aperture <NUM> being located closer to the bottom wall <NUM>. The reason for this offset will be explained below.

The insert member <NUM>, on the other hand, has a generally puck-shaped body <NUM> and a circular positioning lip or flange <NUM> that extends circumferentially around the upper edge of the insert member <NUM>. As shown in <FIG>, the positioning flange <NUM> limits the extent to which the body <NUM> of the insert member can be inserted into the interior of the porting housing <NUM>.

Furthermore, the insert member <NUM> has a notch <NUM> formed at the edge <NUM> of the insert member <NUM>, where the peripheral surface <NUM> of the insert member <NUM> meets the bottom surface <NUM> of the insert member. The notch <NUM> forms a passageway that permits fluid to pass between the bottom surface <NUM> of the insert member <NUM> from a selected one of the tube attachment fittings <NUM> into a space <NUM> and to the attachment fitting <NUM>. One of the attachment fittings <NUM> is selected depending upon the rotational position of the insert member <NUM>.

As further illustrated in <FIG>, the insert member <NUM> is not as thick as the interior of the port housing <NUM> is deep. As a result, a chamber <NUM> is formed between the bottom surface <NUM> of the insert member and the bottom wall <NUM> of the port housing, and the apertures <NUM> are aligned with and opens into the chamber <NUM>. On the other hand, the apertures <NUM> are vertically positioned along the sidewall <NUM> (i.e., in the thickness direction) such that they are blocked by the peripheral surface <NUM> of the insert member, unless the notch <NUM> is positioned in front of a given one of the apertures <NUM>. For an aperture <NUM> that has the notch <NUM> positioned in front of it, fluid is able to flow between that aperture <NUM> and the chamber <NUM>. Thus, more broadly speaking, a fluid-flow pathway will extend through the flow-directing unit 104a from the tube attachment fitting <NUM> and aperture <NUM> having the notch <NUM> positioned in front of it; through the notch <NUM> and chamber <NUM>; and through the aperture <NUM> and tube attachment fitting <NUM>. Furthermore, it will be appreciated that different apertures <NUM> will be opened and other apertures <NUM> closed depending on the rotational position of the insert member <NUM> within the porting housing <NUM>.

A drive-engagement feature <NUM> is provided at the upper surface <NUM> of the insert member <NUM>. For example, as illustrated, the drive-engagement feature <NUM> could be a plus sign-shaped feature that stands proud relative to the upper surface <NUM> of the insert member. Alternatively, the drive-engagement feature could be a slot-shaped or cross-shaped recess; a post; a divot; gear teeth extending radially from the edge of the positioning flange <NUM>; or any other feature that can be engaged by a driving mechanism (illustrated and described below) and used to rotate the insert member <NUM> to a desired angular position within the porting housing <NUM>.

Additionally, a position-indicating feature <NUM> may also be provided on the upper surface <NUM> of the insert member <NUM>. The position-indicating feature <NUM> could be encoder markings that are detected by an optical sensor (illustrated and described below). Alternatively, the position-indicating feature could be indexing slots; magnets; or any other feature that can be sensed by a sensor to determine the angular position of the insert member <NUM>.

Further still, a circumferential recess <NUM> is suitably formed in the peripheral surface <NUM> of the insert member <NUM>, just under the positioning flange <NUM>. A sealing member <NUM> such as an O-ring made from medical-grade material fits within the circumferential recess <NUM> and bears against the radially inner surface <NUM> of the sidewall <NUM> to seal the interior of the flow-directing unit <NUM>. Additionally, means to secure the insert member <NUM> within the porting housing <NUM> (not illustrated) may also be provided. Such means may include clamps; a circumferential flange extending from the peripheral surface <NUM> of the insert member that engages with a corresponding circumferential groove formed in the radially inner surface <NUM> of the sidewall <NUM>; etc..

Use of the porting cassette <NUM> is illustrated in <FIG>. As shown in <FIG>, one of the cassette side parts 106b includes a pair of apertures 162a, 162b through which the flow-directing units 104a, 104b can be accessed. The porting cassette is inserted into a receiving slot <NUM> within the flow-porting section of an automated peritoneal dialysis system (not illustrated), with the flow-directing units 104a, 104b aligned with and accessible to reciprocating drive members 166a, 166b through the apertures 162a, 162b. The reciprocating drive members 166a, 166b have features (e.g., end faces) that are configured to engage with the drive-engagement features <NUM> of the flow-distribution units 104a, 104b so that the drive members 166a, 166b can rotate the insert members <NUM> of the flow-distribution units 104a, 104b to various positions to open and close the various apertures <NUM> of the flow-distribution units. By adjusting the rotational positions of the insert members <NUM> of the flow-distribution units 104a, 104b, the flow of fluid through the incoming-fluid delivery tubes 108a-108f and the outgoing-fluid delivery tubes 112a-112f can be regulated.

The flow-porting section of the automated peritoneal dialysis system includes a controller <NUM>, which receives a flow path command from the system to establish a desired combination of incoming fluid path and outgoing fluid path. The controller <NUM> then commands stepper motors 172a, 172b to drive the drive members 166a, 166b to commanded angular positions to achieve the desired flow path. Furthermore, position sensors 174a, 174b detect the position-indicating features <NUM> on the flow-distribution units 104a, 104b. In this manner, the controller <NUM> is provided with the necessary information to control the positions of the insert members <NUM> of the flow-distribution units 104a, 104b and hence to control the overall fluid-flow pathway.

Given the relatively compact design of the fluid-distribution units, they can be fabricated relatively inexpensively. This is beneficial for medical components that are to be disposed of. Additionally, the design reduces complexity of the overall peritoneal dialysis system in that the settings for just two components - namely, the angular positions of the insert members of the two flow-distribution units - needs to be regulated instead of the actuation states of clamping devices on each of the various fluid-flow lines. Further still, the design affords high assurance that flow will be prevented or allowed through the various lines.

Claim 1:
A disposable medical flow-regulating device (<NUM>), comprising:
a pair of cylindrical flow-directors, each of the cylindrical flow-directors having a housing part and a flow-directing unit (104a, 104b) with tube attachment fittings (110a-110f, <NUM>-114f);
a pumping tube segment (<NUM>) extending from a transfer fitting (<NUM>) on one of the flow-directing units (104a) to the transfer fitting (<NUM>) on the other of the flow-directing units (104b) to establish a fluid flow path between the two flow-directing units (104a, 104b);
each of the flow-directing units (104a, 104b) having a shaped, rotary insert (<NUM>) that rotates within a chamber to select one of the tube attachment fittings (110a-110f, <NUM>-114f) at a given angular position to connect with respective one of the transfer fittings (<NUM>, <NUM>) whereby a selectable channel from a first flow-directing unit tube attachment fitting (110a-110f, <NUM>-114f) to a second flow-directing unit tube attachment fitting (110a-110f, <NUM>-114f) is defined; and
tubing elements (108a-108f, 112a-112f) from a fluid circuit are connected to the tube attachment fittings (110a-110f, <NUM>-114f) of each of the flow-directing units such that selectable flow paths in the fluid circuit may be defined by rotating a respective rotary insert (<NUM>), wherein the pair of cylindrical flow-directors and the pumping tube segment (<NUM>) are partially enclosed in a support frame (106a, 106b) to form a cartridge enclosure (<NUM>).