Patent Application
20230010617
This Invention relates generally to sink drain systems with control features against colonization by pathogenic bacteria, and specifically, to the connection of sink drain systems to vertical drain stacks behind the wall to which the sink is attached wherein the connection enables chemical scouring treatment as well as orthogonally aligned connections.
The healthcare sink enables health care providers to practice hand hygiene prior to, during, and after attending to their patient. A variety of biological material gets washed down healthcare sink drains, leading to colonization of the drain by bacteria and other microorganisms. Drain microorganisms can originate not only from the sink side, but also from vertical drainage stacks or pipes connecting sink drains from floor to floor. For this reason once one sink becomes contaminated with pathogenic bacteria arising from patient material such as blood or stool washed from the hands of a healthcare attendant, pathogens can travel by a plurality of means across, down, and even up drainage connections between sinks in neighboring rooms, to arrive at a neighboring patient room sink via the connection of the sink drain of that neighboring room to the vertical or horizontal drainage stack connecting the original contaminated room sink with the neighboring room sink.
When the drain of the newly colonized sink is colonized by pathogenic bacteria arising from a sick patient in a neighboring room, or from pathogenic bacteria from a previous patient of that room, bacteria have the opportunity to travel by a plurality of means including but not limited to aerosols, splash, and touch transmission. When sink drain bacteria travel to a patient in the newly colonized room, or from a previous patient in that room, a patient can become infected with this travelling pathogenic bacteria. This is called a nosocomial infection. Nosocomial infections can mean a patient can die from an infection that the patient did not have when entering the hospital. And a primary locus of nosocomial infection is the entire drainset of the sink from sink to wall, where drainset refers to all the components including but not limited to drain, tailpiece, trap, wallbend, and connector to the vertical drainage pipe. A sink drain, sometimes called a plug, is a flanged, externally threaded pipe suspended from the drainage hole in the internal bottom of the sink bowl. A tailpiece is a tube running vertically from the downstream outlet of a sink drain to the upstream outlet of a trap. A trap is a bent tube or cast or injected or forged fitting in which drainage water collects in order to prevent sewer gases rising up from the sewer in a vertical drainage stack from entering a patient room. To the downstream egress of the trap is attached a wallbend, a bent pipe or tube leading to the vertical drainage stack comprised of one or more pieces. The wallbend is connected to the stack by a connector, the focus of this Application.
An overlay on simple nosocomial infection is the ready sharing of mobile resistance genes between bacteria meeting somewhere in the drainset of a healthcare sink. As bacteria move along a connection offered by a drainage stack and drainsets, bacteria evolve and accumulate antibiotic resistance through the sharing of genetic information. This transformation of a hospital drainage system into a bioreactor for the evolution of pathogens with multiple resistances for a range of antibiotics was not intended, and needs to be managed to heighten patient safety. A plurality of tools to control drainset bacterial colonization include but are not limited to sink design, drain design, tailpiece length, trap technologies, and chemical disinfection procedures.
One tool would be to remove sinks entirely from healthcare rooms. This is inconvenient for healthcare attendants for a plurality of reasons. Another sink option is to improve sink design to minimize effects that lead to bacterial vectoring that include but are not limited to splash, poor housekeeping owing to the provision of flat surfaces on the sink inviting temporary placement of objects moved elsewhere later, and aerosolization arising from direct impact of a supply faucet water stream on a drain grid. Whether these changes have real impact on pathogen control is rarely tested in gold standard, double blind unbiased experimentation, but does encourage replacement of old sinks with new sinks of different geometries, including but not limited to offset sinks, where the drain in the sink bowl is located off center of a central drain spout, avoiding direct contact of a supply water stream with the drain. Usually there is limited wall width for a sink installation, meaning that the line up or orientation of the drain outlet of a new offset sink does not match the orientation of a pre-existing drainage connection at the wall. This situation can prevent an orthogonal connection, as defined below.
The term orthogonal in connecting plumbing tubes and hubs describes a joining of a tube to a hub where the centerlines of both hub and tube are coincident. Without orthogonality a wallbend tube might be crookedly inserted and fixed into a hub, but with strain captured by the connection in the form of stress in the wallbend, the connector, or the soldering or solvent cementing of the connection itself. While a difference in height of the connection relative to the bottom of the drain tailpiece can be matched by cutting down a long tailpiece, and while a difference in the length of separation between the centerline of the drain and the centerline of the vertical drainage stack behind the wall can also be adjusted by cutting down a long wallbend; in contrast, often the angle of an existing wallbend at the connector cannot be orthogonally matched to the angle of the wallbend connector port of a connector relative to the wall, leading to a plurality of quick fix solutions, including but not limited to flexible rubber connectors and application of torque to a wallbend to make it fit, with predictable impacts on drainage seal, provision of foci for bacterial growth, and the integrity of the drain system, as will be discussed below as a secondary design focus in this Application.
To continue with the drainset, drain design and tailpiece length are other potential tools to limit pathogen spread. Again, experimental evidence must be collected from designed experiments. The challenge is the same as with investigating the performance of changed sink geometries: the statistical sample size necessary to generate results with a high degree of confidence can run to many years of testing over hundreds if not thousands of sinks in busy ICU rooms. Furthermore, this also requires access to patient swab data, a legal barrier. Such studies are expensive and rare, and even if successful, may not apply to a pathogen newly emerging after the study.
Similarly, drain trap technologies can be used as tools to control bacterial colonization of traps with pathogenic microorganisms. The trap of a drain is a U-shaped bend of pipe or cast or injected or forged material through which drain water passes on its way to the vertical drainage stack. Technologies that can be added to the trap include but are not limited to heat, electrical potential difference, antimicrobial coatings, ultraviolet light, and removable traps for sterilization. All of these technologies introduce great capital and maintenance expense to what is otherwise a very inexpensive part.
Downstream to the trap of the sink drain system is the wallbend, a bent piece of tube (external diameter controlled) or pipe (internal diameter controlled) emanating vertically from the downstream end of the trap, bending ninety degrees to form a horizontal tube or pipe, finally connecting to the horizontal connection on the vertical, or at times horizontal, drainage stack. Wallbend infection management tools include but are not limited to antimicrobial materials and slippery internal coatings.
In hospitals around the world at the time of writing of this application, certain pathogenic bacterial species with multiple antibiotic resistance genes, called superbugs, colonize sink drain systems and cannot be eradicated by sink geometry, drain design, tailpiece length, trap technology, wall bend technology, or any combination of these tools. Standard disinfection regimes used in terminal cleaning of rooms, that is, the thorough cleaning of a healthcare room after a patient leaves it permanently, are also not effective against colonization by superbugs. Colonization of connecting drainage vertical stacks worsens this situation—cleaning one drain system leaves it open to re-infection by pathogenic bacteria lurking in the drainage stack.
Herein lies the primary focus of this Application. Even if a series of chemicals poured down the drain could effect albeit temporary kill of persistent bacterial colonization, the effect is limited as there is no significant residence time in the drainset. The chemicals merely flow through the drainset. A tool to increase residence time of chemicals within a drain system could include a drainage stop at the drainage connection between wallbend and the vertical drainage stack. This is a primary design focus of this Application.
Accordingly, it is an object of this invention to at least partially overcome some of the disadvantages of the prior art.
The key to sterilization of sink drainsets by chemicals is to add blockable functionality to the most downstream part of the sink drainset, in order that chemicals may be held long enough for them to kill bacteria lining the drain system between the sink and the wall. This can be accomplished using the connector Invention described in this Application. A secondary benefit of this connector is that it allows for orthogonal connection of the drainset wallbend to the connection attached to the downstream drainage stack, usually vertical. Key features of said connector are that it may be installed in an upward or sideways connection style depending on whether the wallbend has two or one ninety degree bends respectively, that the connector has a sealing cleanout port allowing for access for unblocking and optionally other technologies, and that the connector has a blocker that fits sealingly to the connector to block drainage of the sink drain system to enable extended chemical treatment.
A review of connection terminology is in order. A pipe is an outer diameter controlled hollow cylinder; a tube is an internal diameter controlled hollow cylinder; a hub or expansion is an expanded diameter terminus to a tube or pipe that allows for slidingly sealed insertion of a tube or pipe end; a thread ring is an external thread feature on the end of a hub; a basket nut is a compression nut adorned with a flat annular feature perpendicular to the centerline of a hub that encircles a piece of tube inserted into a connection hub and presses down onto the flange of an annular flanged seal provided in the internal diameter of the proximal hub end of an expansion hub during the process of threading said basket nut onto a thread ring provided around the proximal expansion terminus of the connector hub wherein the annular seal is placed; a solder joint being a heated metal seal between a tube and a hub, a solvent seal is a chemical bonding treatment between a plastic pipe and hub. More recently, an annular metal grip with seal has been added to connection technology used in plumbing.
In the drawings, which illustrate embodiments of the invention:
In some embodiments, aspects of the invention described in this Application comprise a system with a water supply in the form of a faucet, a perforated vessel in the form of a sink, and a drain system connected to a usually vertical drainage stack pipe contained in the wall in front of which is installed the sink. In the figures following, the water supply is not pictured and the drainage stack, either horizontal or vertical behind the wall, is also left out, owing in both cases to the diversity of solutions not relevant to this Invention.
In
In
Toward an explanation of the blocking functionality,
A detail of the same side view with a lateral cutaway 49 of the connector 29 described in this Application with a blocking plug 45 inserted into the cleanout port of the connector 29. The cutaway of the connector 29 wall reveals that the cylinder 51 of the blocking plug interrupts the flow of drainwater exiting the sink into the drain system. While the seal of an outer diameter controlled tube in an internal diameter controlled machined casting is a matter of the tolerance of machining chosen upon, with an appropriate tolerance an effective seal can be achieved that will keep a dose of chemical cleaners in the trap and wall bend for as long as takes to scour the bacteria off the internal walls of the drainset, avoiding the heavy torqueing as well as biofilm growth involved in a packed valve. The question of what to do with the blocker plug after cleaning depends on the materials used in the drainset. For example, a brass blocker plug can be sterilized in a bucket of chemicals, or in an autoclave, and then recycled.
In practice, opening a drainset requires a bucket with bleach in the bottom to catch leaks when the blocking plug is removed and the cleanout cap is replaced.
Accordingly, this Application presents a connector invention that provides a blocking functionality that allows for a thorough soaking of the drainset with appropriate cleaning chemicals over the needed period of time. Since the wall bend is angled to drain, the blocking plug can be designed in a plurality of ways to allow for flow while still inserted. This would be important if a series of different chemical treatments is required. The blocking plug could be shifted from open to closed to open for each stage of chemical treatment without entirely removing the blocking plug until the end of the treatments. Additional technology such as pathogen diagnostic reagents, battery powered ultraviolet light are also possible.
