Patent Description:
Dialysis is a treatment used to support a patient with insufficient renal function. The two principal dialysis methods are hemodialysis and peritoneal dialysis.

During hemodialysis ("HD"), the patient's blood is passed through a dialyzer of a dialysis machine while also passing a dialysis solution or dialysate through the dialyzer. A semi-permeable membrane in the dialyzer separates the blood from the dialysate within the dialyzer and allows diffusion and osmosis exchanges to take place between the dialysate and the blood stream. These exchanges across the membrane result in the removal of waste products, including solutes like urea and creatinine, from the blood. These exchanges also regulate the levels of other substances, such as sodium and water, in the blood. In this way, the dialysis machine acts as an artificial kidney for cleansing the blood.

During peritoneal dialysis ("PD"), a patient's peritoneal cavity is periodically infused with dialysis solution or dialysate. The membranous lining of the patient's peritoneum acts as a natural semi-permeable membrane that allows diffusion and osmosis exchanges to take place between the solution and the blood stream. These exchanges across the patient's peritoneum, like the continuous exchange across the dialyzer in HD, result in the removal of waste products, including solutes like urea and creatinine, from the blood, and regulate the levels of other substances, such as sodium and water, in the blood.

Many PD machines are designed to automatically infuse, dwell, and drain dialysate to and from the patient's peritoneal cavity. The treatment typically lasts for several hours, often beginning with an initial drain cycle to empty the peritoneal cavity of used or spent dialysate. The sequence then proceeds through the succession of fill, dwell, and drain phases that follow one after the other. Each phase is called a cycle.

<CIT> describes an accessory device for use with a hemodialysis system. The accessory device is configured so that it can perform more than one function related to the operation of a hemodialysis machine, including acting as a priming cartridge.

<CIT> describes a system for supplying a blood dialyser with dialysing fluid with connections enabling the system to be connected with the dialyser blood compartment, so that after a dialysing treatment, the supply system can be used to supply washing and sterilizing liquid both to the blood compartment and the dialysate compartment of the dialyser.

<CIT> describes a controlled blood dialysis system.

<CIT> describes that, in priming by a dialysate of arteriovenous blood circuits including a dialyzer of an artificial dialysis apparatus, drainage treatment tablets each formed by compressing and molding acidic agent powder are charged in a drainage funnel provided in an inlet part of a priming drainage line.

In one aspect, a drain apparatus for a dialysis machine includes a chamber, a lid, an inlet line, an outlet line, and a valve. The chamber is configured to receive an end of a fluid line extending from the dialysis machine. The lid is configured to be coupled to the chamber to form a seal with the chamber. A sensor is configured to detect a fluid level in the chamber. The inlet line has first end configured to be coupled to the chamber and a second end configured to be coupled to a fluid line of the dialysis machine. The outlet line has a first end configured to be coupled to the chamber and a second end configured to be coupled to a drain line of the dialysis machine. The valve is coupled to the outlet line and configured to control flow of fluid through the outlet line.

In a further aspect, a method includes emptying contents of a blood line set of a dialysis system into a chamber of a drain apparatus of the dialysis system, closing a lid of the drain apparatus to seal the chamber of the drain apparatus, flowing a disinfectant fluid through an inlet line of the drain apparatus from a dialysis machine of the dialysis system to the drain apparatus to at least partially fill the chamber of the drain apparatus with the disinfectant fluid, and flowing the disinfectant fluid through an outlet line of the drain apparatus from the drain apparatus to a drain line of the dialysis machine.

Implementations can include one or more of the following features.

A dialysis system can includes a dialysis machine with a fluid line and a drain line, a blood line set configured to be connected to the dialysis machine, and the drain apparatus coupled to the dialysis machine. The first end of the inlet line of the drain apparatus is coupled to the chamber and a second end coupled to the fluid line of the dialysis machine. The first end of the outlet line is coupled to the chamber and the second end is coupled to the drain line of the dialysis machine.

In some implementations, the fluid line and the drain line are parts of a hydraulic circuit of the dialysis machine and the dialysis system further includes a dialyzer connected to the hydraulic circuit of the dialysis machine.

In certain implementations, the drain line is downstream of the dialyzer.

In some implementations, the fluid line is upstream of the dialyzer.

In certain implementations, the second end of the outlet line is configured to be coupled to the drain line at a location upstream of a post-dialyzer flow pump of the dialysis machine.

In some implementations, the second end of the outlet line is configured to be coupled to the drain line at a location of the dialysis machine downstream of a drain valve of the dialysis machine.

In certain implementations, the drain apparatus further includes a pump coupled to outlet line and configured to pump fluid from the chamber of the drain apparatus to the drain line of the dialysis machine.

In some implementations, the drain apparatus is configured to drain fluid contained in the chamber of the drain apparatus through the outlet line of the drain apparatus to the drain line of the dialysis machine by gravity when the valve of the drain apparatus is in an open position.

In certain implementations, the second end of the inlet line is configured to be coupled to a portion of the fluid line downstream of a fluid filter of the dialysis machine.

In some implementations, the drain apparatus includes a lid coupled to the chamber and configured to form a seal with the chamber.

In certain implementations, the lid includes a vent and a hydrophobic filter disposed within the vent.

In some implementations, the chamber includes an inner funnel coupled to and nested within an outer funnel.

In certain implementations, the inner funnel and outer funnel form an annular channel and the first end of the inlet line is fluidly connected to the annular channel.

In some implementations, the annular channel is formed between an outer surface of the inner funnel and an inner surface of the outer funnel.

In certain implementations, the drain apparatus further includes a pump coupled to the outlet line.

In some implementations, the drain apparatus further includes one or more mechanical attachment devices coupled to the chamber and configured to position the end of a patient line extending from the dialysis machine inside the chamber.

In certain implementations, the drain apparatus further includes a vent extending through the lid, and a hydrophobic membrane coupled to the vent.

In certain implementations, the sensor includes a pressure sensor coupled to the outlet line.

In some implementations, the sensor includes an ultrasound sensor coupled to the chamber.

In certain implementations, the sensor includes an ultrasonic sensor and an ultrasonic receiver coupled to the lid.

In some implementations, the sensor includes a light transmitter and a light receiver coupled to the lid.

In certain implementations, the sensor includes one or more electrodes coupled to the chamber.

In some implementations, the lid includes one or more vent holes.

In certain implementations, emptying contents of a blood line set of a dialysis system into a chamber of a drain apparatus of the dialysis system includes connecting a patient line of the blood line set to the drain apparatus of the dialysis machine following performance of dialysis on a patient, flowing a saline solution through the patient line of the blood line set into the drain apparatus to flush remaining fluid in the blood line set into the drain apparatus, and disconnecting the patient line of the blood line set from the drain apparatus.

In some implementations, the method further includes stopping flow of the disinfectant fluid upon receiving a signal from a sensor coupled to the drain apparatus indicating that the chamber of the drain apparatus is filled with disinfectant solution.

In certain implementations, the disinfectant fluid dwells in the chamber of the drain apparatus for a predetermined amount of time.

In some implementations, flowing the disinfectant fluid through the outlet line of the drain apparatus from the drain apparatus to the drain line of the dialysis machine includes opening a valve coupled to the outlet line of the drain apparatus.

In certain implementations, flowing the disinfectant fluid through the outlet line of the drain apparatus from the drain apparatus to the drain line of the dialysis machine includes pumping the disinfectant fluid in the chamber of the drain apparatus to the drain line using a pump coupled to the outlet line of the drain apparatus.

In some implementations, flowing the disinfectant fluid through the outlet line of the drain apparatus from the drain apparatus to the drain line of the dialysis machine includes using negative pressure generated by a flow pump of the dialysis machine to pump the disinfectant fluid in the chamber of the drain apparatus to the drain line.

In certain implementations, the disinfectant fluid includes a chemical disinfectant.

In some implementations, the disinfectant fluid is hot water.

In certain implementations, flowing the disinfectant fluid through the inlet line of the drain apparatus from the dialysis machine to the drain apparatus to at least partially fill the chamber of the drain apparatus includes flowing the disinfectant fluid into the chamber at a rate sufficient to maintain a predetermined level of fluid in the chamber for a predetermined amount of time.

Advantages of the systems, devices, and methods described herein include ease of use for the user. By providing a drain apparatus that is coupled to the drain line of the dialysis machine, emptying and disinfecting the drain apparatus following priming or flushing patient lines is simplified by reducing the need to drain and sterilize the drain apparatus separately from the dialysis machine. Another advantage is that by incorporating the disinfection of the drain apparatus used for priming and flushing patient lines with disinfection of the dialysis machine, the overall time required to disinfect the drain apparatus and the dialysis machine is reduced. Another advantage is a reduced risk of spills and biohazards. For example, since the drain apparatus can be disinfected and drained while remaining connected to the dialysis machine, the need to transport the drain apparatus for disinfection, and thus risk spilling the contents of drain apparatus (e.g., patient line fluids), is greatly reduced.

Referring to <FIG>, a hemodialysis system <NUM> includes a hemodialysis machine <NUM> to which a disposable blood component set <NUM> that forms a blood circuit is connected. During hemodialysis, arterial and venous patient lines <NUM>, <NUM> of the blood component set <NUM> are connected to a patient and blood is circulated through various blood lines and components, including a dialyzer <NUM>, of the blood component set <NUM>. At the same time, dialysate is circulated through a dialysate circuit (shown in <FIG>) formed by the dialyzer <NUM> and various other dialysate components and fluid lines connected to the hemodialysis machine <NUM>. Many of these dialysate components and fluid lines are located inside the housing of the hemodialysis machine <NUM>, and are thus not visible in <FIG>. The dialysate passes through the dialyzer <NUM> along with the blood. The blood and dialysate passing through the dialyzer <NUM> are separated from one another by a semi-permeable structure (e.g., a semi-permeable membrane and/or semi-permeable microtubes) of the dialyzer <NUM>. As a result of this arrangement, toxins are removed from the patient's blood and collected in the dialysate. The filtered blood exiting the dialyzer <NUM> is returned to the patient. The dialysate that exits the dialyzer <NUM> includes toxins removed from the blood and is commonly referred to as "spent dialysate. " The spent dialysate is routed from the dialyzer <NUM> to a drain via a drain line <NUM>.

Still referring to <FIG>, the dialysate circuit of the hemodialysis machine <NUM> is formed by multiple dialysate components and fluid lines positioned inside the housing of the hemodialysis machine <NUM> as well as the dialyzer <NUM>, a dialyzer inlet line <NUM>, and a dialyzer outlet line <NUM> that are positioned outside of the housing of the hemodialysis machine <NUM>. The dialyzer inlet line <NUM> includes a connector adapted to connect to one end region of the dialyzer <NUM>, and the dialyzer outlet line <NUM> includes a connector adapted to connect to another end region of the dialyzer <NUM>.

Still referring to <FIG>, the hemodialysis machine <NUM> includes a touch screen <NUM> and a control panel <NUM>. The touch screen <NUM> and the control panel <NUM> allow the operator to input various different treatment parameters to the hemodialysis machine <NUM> and to otherwise control the hemodialysis machine <NUM>. In addition, the touch screen <NUM> serves as a display to convey information to the operator of the hemodialysis system <NUM>. A speaker <NUM> is positioned below the touch screen <NUM> and functions to provide audio signals to the operator of the system <NUM>. Thus, the hemodialysis machine <NUM> is capable of providing both visual alerts via the touch screen <NUM> and audio alerts via the speaker <NUM> to the operator of the system <NUM> during use.

The blood component set <NUM> of the hemodialysis system is secured to a module <NUM> attached to the front of the hemodialysis machine <NUM>. The module <NUM> includes a blood pump <NUM> capable of driving blood through the blood circuit. The module <NUM> also includes various other instruments capable of monitoring the blood flowing through the blood circuit. The module <NUM> includes a door <NUM> that when closed, as shown in <FIG>, cooperates with the front face of the module <NUM> to form a compartment sized and shaped to receive the blood component set <NUM>. In the closed position, the door <NUM> presses certain blood components of the blood component set <NUM> against corresponding instruments exposed on the front face of the module <NUM>. This arrangement facilitates control of the flow of blood through the blood circuit and monitoring of the blood flowing through the blood circuit.

As depicted in <FIG>, the hemodialysis system <NUM> also includes a drain apparatus <NUM> coupled to the hemodialysis machine <NUM>. The drain apparatus <NUM> includes a lid <NUM>, an inlet port <NUM>, an outlet port <NUM>, an inlet line <NUM>, an outlet line <NUM>, a drain apparatus pump <NUM>, and an outlet valve <NUM>.

In some implementations, the lid <NUM> is coupled to the body of the drain apparatus <NUM> with a hinge. During use, the lid <NUM> of the drain apparatus <NUM> may be opened and the venous patient line <NUM> of the blood component set <NUM> may be placed within a chamber of the drain apparatus <NUM> to expel fluid from the venous patient line <NUM> into the chamber of the drain apparatus <NUM>.

The components of the hemodialysis machine <NUM> and the drain apparatus <NUM> can be disinfected between treatments. For example, a disinfectant fluid can be provided to and circulated through the hydraulic circuit of the hemodialysis machine <NUM> and the drain apparatus <NUM> between treatments in order to disinfect the hemodialysis machine <NUM> and drain apparatus <NUM>. As described in further detail herein, the drain apparatus <NUM>, when not in use, can be disinfected by closing the lid <NUM> and flowing disinfection fluid through the chamber of the drain apparatus <NUM>.

<FIG> depicts a cross section view of the drain apparatus <NUM> with the lid <NUM> closed. As depicted in <FIG>, the drain apparatus includes an inner funnel <NUM> and an outer funnel <NUM>. The inner funnel <NUM> forms a chamber <NUM> within the drain apparatus <NUM> configured to receive and collect liquid. The outer funnel <NUM> includes an upper lip <NUM> that encompasses an annular surface <NUM> of the inner funnel <NUM>. The inner funnel <NUM> of the drain apparatus <NUM> is nested within and connected to an outer funnel <NUM> of the drain apparatus <NUM>. As shown in <FIG>, the inner funnel <NUM> is connected to the outer funnel <NUM> proximate the outlet port <NUM> of the drain apparatus <NUM>. The inner funnel <NUM> can be connected to the outer funnel <NUM> by any suitable techniques, such as welding, injection molding, etc..

The nested arrangement of the inner funnel <NUM> and the outer funnel <NUM> creates an annular channel <NUM> between the inner funnel <NUM> and the outer funnel <NUM> that surrounds the inner funnel <NUM>. Fluid received through the inlet port <NUM> from the inlet line <NUM> can travel through the annular channel <NUM> between the inner funnel <NUM> and the outer funnel <NUM>, over the annular surface <NUM> of the inner funnel <NUM>, and into the chamber <NUM> of the drain apparatus. Arranging the inner funnel <NUM> and outer funnel <NUM> to create a <NUM> degree annular channel <NUM> enables fluid to be fairly evenly distributed to the entire surface of the chamber <NUM> of the drain apparatus <NUM>. In some examples, the inner funnel <NUM> and outer funnel <NUM> are arranged to form an annular channel <NUM> with a width of about <NUM> (<NUM> inches) to about <NUM> (<NUM> inches).

The inner funnel <NUM> and the outer funnel <NUM> of the drain apparatus <NUM> can be formed of any of various different medical grade materials. Examples of such materials include PVC, polyethylene, polypropylene, silicone, polyurethane, high density polyethylene, nylon, ABS, acrylic, isoplast, polyisoprene, polycarbonate, stainless steel, glass, titanium, carbon fiber, and porcelain.

As shown in <FIG>, a clip <NUM> is attached to the upper lip <NUM> of the outer funnel <NUM>. The clip <NUM> is configured to receive the venous patient line <NUM> of the hemodialysis system <NUM> and to position a patient end of venous patient line <NUM> within the chamber <NUM> of the drain apparatus. As described in the further detail herein, the chamber <NUM> is configured to collect fluids contained within the blood lines and provide the collected fluids to a drain via the outlet line <NUM> of the drain apparatus <NUM>.

Still referring to <FIG>, the drain apparatus <NUM> also includes a screen <NUM> located within and coupled to the inner funnel <NUM> of the drain apparatus <NUM>. The screen <NUM> is configured to prevent particulates above a defined size from entering, and potentially obstructing, the outlet line <NUM>. For example, the screen <NUM> includes a plurality of openings sized to allow fluid to flow through the screen <NUM> while preventing particulates above a defined size from entering the outlet line <NUM>. In some examples, the screen <NUM> includes openings with a diameter of about <NUM> (<NUM> inches) to about <NUM> (<NUM> inches) (e.g., <NUM> (<NUM> inch) diameter). The screen <NUM> is positioned in a location within the chamber <NUM> prevents blood lines positioned within the chamber <NUM> using the clip <NUM> from contacting the screen <NUM>. In some implementations, the screen <NUM> is removable and can be removed from the drain apparatus <NUM> for cleaning. The screen <NUM> can be formed of any of various different medical grade materials. Examples of such materials include PVC, polyethylene, polypropylene, silicone, polyurethane, high density polyethylene, nylon, ABS, acrylic, isoplast, polyisoprene, polycarbonate, stainless steel, titanium, and carbon fiber.

As shown in <FIG>, the lid <NUM> of the drain apparatus <NUM> includes a vent <NUM> with a hydrophobic filter <NUM>. The vent <NUM> extends through the lid <NUM> to outside the drain apparatus <NUM>. A coupler <NUM> is coupled to the vent <NUM> to create a fluid seal between the vent <NUM> and the lid <NUM>. The hydrophobic filter <NUM> is arranged within the vent <NUM>. As described in further detail herein, as the chamber <NUM> of the drain apparatus <NUM> is filled with fluid, air contained within the chamber <NUM> is displaced by the fluid and exits out the vent <NUM>, allowing for complete filling of the chamber <NUM>. Further, the hydrophobic filter <NUM> prevents liquids provided to the chamber <NUM> from exiting through the vent <NUM>. The hydrophobic filter <NUM> may be made of a hydrophobic material, such as polytetrafluoroethylene (PTFE) (e.g., expanded polytetrafluoroethylene (ePTFE)), a blend of polyethylene and carboxymethylcellulose, etc. In certain implementations, the hydrophobic filter <NUM> is a fibrous carrier with a matted and woven layer on top of which ePTFE or other micro-porous material is applied. The vent <NUM> can includes a plurality of pores, each pore having a diameter of about <NUM> to about <NUM> (e.g., <NUM>). In some examples, a material of the vent <NUM> expands in response to contacting fluid, which closes the plurality of pores in the vent <NUM> and prevents fluid from passing through the vent <NUM>.

Still referring to <FIG>, the inlet port <NUM> of the drain apparatus <NUM> is coupled to the inlet line <NUM>. In some implementations, the inlet line <NUM> is coupled to the inlet port <NUM> using a coupler. The inlet line <NUM> can be coupled to the inlet port <NUM> using a metal band or plastic band that restricts the tubing of the inlet line <NUM> around a barb of the inlet port <NUM>. A first end of the inlet line <NUM> is coupled to the inlet port <NUM> and a second end of the inlet line <NUM> is coupled to a fluid line of the hemodialysis machine <NUM>.

In the implementation shown in <FIG>, a drain apparatus inlet valve <NUM> is fluidly connected to the inlet line and is configured to control the flow of fluids into the chamber <NUM> via the inlet line <NUM>. The drain apparatus inlet valve <NUM> can be communicatively coupled to the hemodialysis machine <NUM> and can be opened and closed in response to signals received from the hemodialysis machine <NUM>. An example of a suitable valve is a solenoid valve.

The outlet port <NUM> of the drain apparatus <NUM> is coupled to the outlet line <NUM>. In some implementations, the outlet line <NUM> is coupled to the outlet port <NUM> using a coupler. The outlet line <NUM> can be coupled to the outlet port <NUM> using a metal band or plastic band that restricts the tubing of the outlet line <NUM> around a barb of the outlet port <NUM>. As described in further detail herein, a first end of the outlet line <NUM> is coupled to the outlet port <NUM> and a second end of the outlet line <NUM> is coupled to a drain line <NUM> of the hemodialysis machine <NUM>.

The drain apparatus outlet valve <NUM> is fluidly connected to the outlet line <NUM> of the drain apparatus <NUM> and is configured to control the flow of fluid from the outlet line <NUM> to the drain line <NUM>. In some implementations, the drain apparatus outlet valve <NUM> is communicatively coupled to the hemodialysis machine <NUM> and can be opened and closed in response to signals received from the hemodialysis machine <NUM>. An example of a suitable valve is a solenoid valve.

As shown in <FIG>, the drain pump <NUM> is fluidly coupled to the outlet line <NUM> of the drain apparatus <NUM>. The drain pump <NUM> is configured to pump fluid from the chamber <NUM> of the drain apparatus <NUM> through the outlet line <NUM> to the drain line <NUM> of the hemodialysis machine <NUM>. Any of various suitable pumps can be used, such as a peristaltic pump, a piston pump, an impeller pump, a magnetically driven gear pump, etc..

The inlet line <NUM> and the outlet line <NUM> of the drain apparatus <NUM> can be formed of any of various different medical grade materials. Examples of such materials include PVC, polyethylene, polypropylene, silicone, polyurethane, high density polyethylene, nylon, ABS, acrylic, isoplast, polyisoprene, and polycarbonate.

Still referring to <FIG>, a pressure sensor <NUM> is coupled to the outlet line <NUM> of the drain apparatus <NUM> proximate the outlet port <NUM>. The pressure sensor <NUM> is configured to measure the fluid pressure in the chamber <NUM> of the drain apparatus <NUM>. For example, the pressure inside the chamber <NUM> can be measured by the pressure sensor <NUM> while the chamber <NUM> is being filled with disinfectant fluid in order to determine when the chamber <NUM> is filled with disinfectant fluid based on the pressure in the chamber <NUM>. In some implementations, the pressure sensor <NUM> is an inline pressure transducer. Other types of pressure sensors that can be used include other types of pressure transducers, such as an M3200 pressure transducer.

<FIG> depicts a perspective view of the drain apparatus <NUM> of <FIG> with the lid <NUM> of the drain apparatus <NUM> in an open position and the venous patient line <NUM> attached to the drain apparatus <NUM> via the clip <NUM>. <FIG> depicts a perspective view of the drain apparatus <NUM> with the lid <NUM> in the closed position. As depicted in <FIG> and <FIG>, the lid <NUM> is attached to the outer funnel <NUM> by a hinge <NUM> such that the lid <NUM> can be moved between the open position depicted in <FIG> and the closed position depicted in <FIG>. The lid <NUM> forms a seal with the outer funnel <NUM> to seal the chamber <NUM> when in the closed position to prevent fluids from escaping the top of the chamber <NUM>. The lid <NUM> can be opened or closed based on the process being performed by the hemodialysis machine or the stage of hemodialysis treatment. For example, the lid <NUM> can be opened to receive the venous patient line <NUM> for draining contents of the line <NUM> into the drain apparatus. The lid <NUM> can be closed during disinfection of the drain apparatus <NUM>, as described in further detail herein.

As previously discussed, the dialysate circuit of the hemodialysis machine <NUM> of <FIG> is formed by multiple dialysate components and fluid lines positioned inside the housing of the hemodialysis machine <NUM> as well as the dialyzer <NUM>, the dialyzer inlet line <NUM>, and the dialyzer outlet line <NUM> that are positioned outside of the housing of the hemodialysis machine <NUM>.

<FIG> is a schematic showing the flow paths of fluids into, through, and out of the dialysate circuit <NUM>. The dialysate circuit <NUM> includes a number of dialysate components that are fluidly connected to one another via a series of fluid lines and the drain line <NUM>.

Still referring to <FIG>, a water inlet port <NUM> is configured to receive water from an external source and provide the water to a heat exchanger <NUM> via the fluid line. Heat exchanger <NUM> is configured to warm the water received by the dialysate circuit <NUM> through the water inlet port <NUM> using the heat of spent dialysate (or other fluid) flowing on an opposite side of the heat exchanger <NUM>.

After exiting the heat exchanger <NUM>, the warmed water flows to the deaeration and heating chamber <NUM>. The deaeration and heating chamber <NUM> is configured to heat and deaerate water received by the dialysate circuit <NUM> through the water port <NUM>. The heating and deaeration chamber <NUM> includes a temperature control thermistor <NUM> for monitoring the temperature of the heated water and a heater <NUM> to increase the temperature of the water received by the chamber <NUM>. For example, if the temperature of the water received by the deaeration and heating chamber <NUM> is below a threshold temperature, as detected by temperature control thermistor <NUM>, the heater <NUM> can be used to heat the water above the threshold temperature. An aeration orifice <NUM> is positioned between two of the sub-chambers 512C, 512D and is configured deaerate the flow of water as the deaeration pump <NUM> pumps the water from sub-chamber 512A to sub-chamber 512E.

The warmed and deaerated water flows from sub-chamber 512E to mixing chambers <NUM>, <NUM> where the water, acid concentrate, and bicarbonate concentrate are mixed. The dialysate circuit <NUM> includes an acid concentrate pump <NUM> coupled to a source of acid concentrate. The acid concentrate pump <NUM> is configured to pump acid concentrate into the flow of water travelling from the deaeration and heating chamber <NUM> to the mixing chambers <NUM>, <NUM>.

The dialysate circuit <NUM> also includes a bicarbonate pump <NUM> that is coupled to a source of bicarbonate. The bicarbonate pump <NUM> is configured to pump bicarbonate into the flow of water and acid concentrate between the deaeration and heating chamber <NUM> and the mixing chamber <NUM>, <NUM>.

The mixing chambers <NUM>, <NUM> are fluidly connected to a fluid line downstream of the acid concentrate pump <NUM> and bicarbonate pump <NUM>, and are configured to receive the combined flow of heated water, acid concentrate, and bicarbonate and mix the fluids to generate a uniform dialysate fluid. As shown in <FIG>, the mixing chambers <NUM>, <NUM> are arranged serially to ensure thorough mixing of the dialysate solution.

Balancing devices <NUM>, <NUM> are fluidly connected to a fluid line downstream of the mixing chambers <NUM>, <NUM>. The balancing devices <NUM>, <NUM> each include a spherical chamber that is divided into a first chamber half <NUM>, <NUM> and a second chamber half <NUM>, <NUM> by a flexible membrane <NUM>, <NUM>. As fluid flows into the first chamber halves <NUM>, <NUM>, fluid is forced out of the second chamber halves <NUM>, <NUM>, and vice versa. Valves <NUM> through <NUM> are used to control the flow of dialysate into and out of the balancing devices <NUM>, <NUM> such that as fresh dialysate is flowing into one balancing device <NUM>, spent dialysate is flowing into the other balancing device <NUM>, and vice versa. For example, as spent dialysate flows into the second chamber half <NUM> of balancing device <NUM> and forces fresh dialysate to flow out of first chamber half <NUM> of balancing device <NUM> towards the dialyzer <NUM>, fresh dialysate flows into first chamber half <NUM> of balancing device <NUM> and forces spent dialysate to flow out of the second chamber half <NUM> of balancing device <NUM> towards the drain, and vice versa. This alternation of fresh and spent dialysate flowing into the balancing devices <NUM>, <NUM> is controlled by valves <NUM> through <NUM>. This balancing device construction and alternating flow of fresh and spent dialysate helps to ensure that the volume of fluid entering the balancing devices <NUM>, <NUM> is equal to the volume of fluid exiting the balancing devices <NUM>, <NUM>. This helps to ensure that the volume of fresh dialysate entering the dialysate circuit is equal to the volume of spent dialysate exiting the dialysate circuit when desired during treatment, as described in greater detail below.

During hemodialysis, fresh dialysate passing through the first chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM> is directed to the dialyzer <NUM> through a dialysate filter <NUM>. Prior to filtration by dialysate filter <NUM>, the fresh dialysate flows through a conductivity cell <NUM> and a temperature monitor thermistor <NUM> downstream of the of the balancing devices <NUM>, <NUM>. The conductivity cell <NUM> and temperature monitor thermistor <NUM> regulate the temperature of the fresh dialysate entering the filter <NUM> and dialyzer <NUM>. The fresh dialysate flowing out of balancing devices <NUM>, <NUM> flows along a fluid line through the dialysate filter <NUM>, which is configured to filter the fresh dialysate received from the balancing devices <NUM>, <NUM> prior to providing the dialysate to the dialyzer <NUM>. One example of such a dialysate filter <NUM> is the DIASAFE®plus dialysis fluid filter available from Fresenius Medical Care filter. During hemodialysis, a bypass valve <NUM> is closed and a dialyzer inlet valve <NUM> is open in order to direct the flow of dialysate from the dialysate filter <NUM> to the dialyzer <NUM>.

During hemodialysis, the fresh dialysate flowing out of the first chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM> is directed through the dialyzer <NUM> toward the air separation chamber <NUM>. Spent dialysate exits the dialyzer <NUM> along a drain line <NUM> of the dialysate circuit <NUM>. A pressure sensor <NUM> located along the drain line <NUM> connecting the dialyzer <NUM> to the air separation chamber <NUM> is adapted to measure the pressure of the spent dialysate exiting the dialyzer <NUM>. Any of various different types of pressure sensors capable of measuring the pressure of the spent dialysate passing from the dialyzer <NUM> to the air separation chamber <NUM> can be used.

The spent dialysate exiting the dialyzer <NUM> collects in the air separation chamber <NUM>. The air separation chamber <NUM> uses an air sensor coupled to the air separation chamber <NUM> to detect air contained within the spent dialysate, and the air separation chamber <NUM> vents off any air contained with the spent dialysate. Air detected in the spent dialysate by the equalizing chamber travels through the vent valve <NUM> to the drain.

A dialysate flow pump <NUM> is configured to pump the spent dialysate from the air separation chamber <NUM> through a fluid line to the second chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM>. As previously discussed, the flow of spent dialysate into the balancing devices <NUM>, <NUM> is controlled by valves <NUM> and <NUM> to alternate the flow of spent dialysate between each of the second chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM>.

As one of the second chamber halves <NUM>, <NUM> of one of the balancing devices <NUM>, <NUM> fills with the spent dialysate, fresh dialysate within the first chamber half <NUM>, <NUM> of the respective balancing device <NUM>, <NUM> is expelled towards the dialyzer <NUM>. Subsequently, as the first chamber half <NUM>, <NUM> of the respective balancing device <NUM>, <NUM> is refilled with fresh dialysate, the spent dialysate is forced out the second chamber half <NUM>, <NUM> of the respective balancing device <NUM>, <NUM> is through one of valves <NUM>, <NUM>, respectively, via drain line <NUM> to the drain. As previously discussed, as fresh dialysate is flowing into one balancing device <NUM>, spent dialysate is flowing into the other balancing device <NUM>, and vice versa.

As shown in <FIG>, an ultrafiltration line <NUM> is connected to an outlet of the air separation chamber <NUM>. An ultrafiltration pump <NUM> is operatively connected to the ultrafiltration line <NUM> such that when the ultrafiltration pump <NUM> is operated, spent dialysate can be pulled from the air separation chamber <NUM> and directed to the drain via the ultrafiltration line <NUM>. Operation of the ultrafiltration pump <NUM> while simultaneously operating the dialysate flow pump <NUM> causes increased vacuum pressure within the line connecting the air separation chamber <NUM> to the dialyzer <NUM>, and thus creates increased vacuum pressure within the dialyzer <NUM>. As a result of this increased vacuum pressure, additional fluid is pulled from the blood circuit into the dialysate circuit across the semi-permeable structure (e.g., semi-permeable membrane or semi-permeable microtubes) of the dialyzer <NUM>. Thus, the ultrafiltration pump <NUM> can be operated to remove excess fluid from the patient.

As shown in <FIG>, the inlet line <NUM> of the drain apparatus is connected to a fluid line of the dialysate circuit downstream of the dialysate filter <NUM> and upstream of the dialyzer <NUM>. The dialyzer inlet valve <NUM> along a fluid line downstream of the dialysate filter <NUM> can be closed in order to direct flow of fluid exiting the dialysate filter <NUM> to the inlet line <NUM> and chamber <NUM> of the drain apparatus <NUM>.

Still referring to <FIG>, the outlet line <NUM> of the drain apparatus <NUM> is coupled to drain line <NUM> downstream of the drain valve <NUM> of the drain line <NUM>. As previously discussed, a drain apparatus outlet valve <NUM> is positioned along the outlet line <NUM>. When the valve <NUM> is closed, fluid provided to the chamber <NUM> through the inlet line <NUM> collects in the chamber <NUM> of the drain apparatus <NUM>. In some examples, fluid is continuously provided from a fluid line of the dialysate circuit <NUM> to the drain apparatus <NUM> via the inlet line <NUM> until the pressure sensor <NUM> positioned along the outlet line <NUM> detects a pressure in the chamber <NUM> of the drain apparatus <NUM> indicating that the chamber <NUM> is full of fluid. Opening the valve <NUM> allows fluid collected in the chamber <NUM> of the drain apparatus <NUM> to flow through the outlet line <NUM> to the drain line <NUM>. For example, after a heated disinfectant fluid provided to the chamber <NUM> via the inlet line <NUM> has been allowed to dwell in the chamber <NUM> for a predetermined amount of time, the valve <NUM> can be opened to drain the disinfectant fluid from the chamber <NUM> to the drain line <NUM>. The drain apparatus pump <NUM> positioned along the outlet line <NUM> can also be used to pump fluid from the chamber <NUM> of the drain apparatus <NUM> to the drain line <NUM> via the outlet line <NUM>.

The various fluid lines and drain line <NUM> of the dialysate circuit <NUM>, as well as the lines <NUM> and <NUM>, can be formed of any of various different medical grade materials. Examples of such materials include PVC, polyethylene, polypropylene, silicone, polyurethane, high density polyethylene, nylon, ABS, acrylic, isoplast, polyisoprene, and polycarbonate.

<FIG> is a schematic showing the flow paths of fluids into, through, and out of the blood circuit <NUM> of the hemodialysis system <NUM>. During hemodialysis treatment, one end <NUM> of the arterial patient line <NUM> is fluidly connected to an artery of a patient <NUM>. The arterial patient line <NUM> is also fluidly connected to an arterial pressure sensor <NUM>. Arterial pressure sensor <NUM> is fluidly connected to the arterial patient line <NUM> and is configured to measure the pressure of the blood flowing the arterial patient line <NUM>. As shown in <FIG>, the arterial pressure sensor <NUM> is positioned upstream of the blood pump <NUM> to measure a pre-pump arterial pressure. Upon detecting that the pressure within the blood circuit <NUM> has dropped below a certain level, the arterial pressure sensor <NUM> can transmit a signal to that effect to the hemodialysis machine <NUM>, which can activate an audio and/or visual alarm to alert the operator of the system of a drop in blood pressure of the patient <NUM>. In some implementations, the arterial pressure sensor <NUM> is provided as combination of a pressure transducer aligned with a pressure sensor capsule. For example, a pressure transducer may be positioned on a door <NUM> of the module <NUM> such that when the door <NUM> is closed, the pressure transducer presses against the pressure capsule and can measure the pressure of blood flowing through the capsule. For example, as the fluid pressure changes within the pressure sensor capsule, the amount of pressure applied to the pressure transducer by the pressure sensor capsule also changes.

The arterial patient line <NUM> extends from the patient <NUM> to a first pump line adaptor <NUM>, which connects the arterial patient line <NUM> to one end of a U-shaped pump line <NUM>. The other end of the pump line <NUM> is connected to a second pump line adaptor <NUM>, which is fluidly connected to a dialyzer inlet line <NUM>. The dialyzer inlet line <NUM> is connected via a tube adaptor to a blood entry port <NUM> of the dialyzer <NUM>. A blood exit port <NUM> of the dialyzer <NUM> is connected to another tube adaptor, which connects the dialyzer <NUM> to a dialyzer outlet line <NUM>. The blood pump <NUM> pumps blood from the artery of the patient <NUM> through the arterial patient line <NUM> to the dialyzer <NUM>.

A venous pressure sensor <NUM> is positioned along a dialyzer outlet line <NUM>, upstream of an air release device <NUM> and is configured to monitor blood pressure on the venous side of the dialyzer <NUM>. In some implementations, the venous pressure sensor <NUM> is provided as combination of a pressure transducer aligned with a pressure sensor capsule. For example, a pressure transducer may be positioned on a door <NUM> of the module <NUM> such that when the door <NUM> is closed, the pressure transducer presses against the pressure capsule and can measures the pressure of blood flowing through the capsule. For example, as the fluid pressure changes within the pressure sensor capsule, the amount of pressure applied to the pressure transducer by the pressure sensor capsule also changes.

As shown in <FIG>, the dialyzer outlet line <NUM> is coupled to an air release device <NUM>. The air release device <NUM> includes a vent assembly <NUM> located at the top of the air release device <NUM>. The vent assembly <NUM> allows air to pass therethrough while inhibiting (e.g., preventing) liquid from passing therethrough. If blood passing through the blood circuit <NUM> during treatment contains air, the air will be vented to the atmosphere as the blood passes through the air release device <NUM>.

In some implementations, the module <NUM> of the hemodialysis machine <NUM> includes a level detector <NUM> that aligns with the air release device <NUM> when the blood component set <NUM> is secured to the front face of the module <NUM>. The level detector <NUM> is adapted to detect the level of liquid (e.g., blood and/or saline) within the air release device <NUM>.

Still referring to <FIG>, a venous patient line <NUM> is connected to an exit port of the air release device <NUM> at a first end and is fluidly connected to a vein of a patient <NUM> during treatment at a second end <NUM>.

An air bubble detector <NUM> is positioned along the venous patient line <NUM> downstream of the air release device <NUM>. The air bubble detector <NUM> is capable of detecting air bubbles within the venous patient line <NUM>. The air bubble detector <NUM> includes a housing that forms a channel in which the venous patient line <NUM> is received. In some implementations, the door <NUM> of the module <NUM> of the hemodialysis machine <NUM> includes a fin that presses the venous patient line <NUM> into the channel of the housing and against a sensor of the air bubble detector <NUM> when the door <NUM> is closed.

An occluder <NUM> is positioned along the venous patient line <NUM> downstream of the air bubble detector <NUM>. The occluder <NUM> is configured to crimp the portion of the venous patient line <NUM> disposed therein to prevent blood from passing through the venous patient line <NUM> when activated. The occluder <NUM> can, for example, be connected to the air bubble detector <NUM> so that the occluder <NUM> can be activated when the air bubble detector <NUM> detects an air bubble within the venous patient line <NUM>. Such an arrangement helps to ensure that no air bubbles reach the patient in the event that the air release device <NUM> fails to remove one or more air bubbles from the blood. Similar to the air bubble detector <NUM>, the occluder <NUM> includes a housing that forms a channel in which the venous patient line <NUM> is received. In some implementations, the door <NUM> of the module <NUM> includes a fin that presses the venous patient line <NUM> into the channel of the housing of the occluder <NUM> when the door <NUM> is closed.

In addition to the blood lines forming the main blood circuit <NUM>, a saline delivery line <NUM> and a drug delivery line <NUM> can be connected to the blood circuit <NUM> for the introduction of saline and drugs (e.g., heparin), respectively, into the blood circuit <NUM>. As depicted in <FIG>, the saline delivery line <NUM> is connected at a first end to a saline bag <NUM> and at a second end to the first pump line adaptor <NUM>.

The drug delivery line <NUM> is connected at a first end to a syringe <NUM>, which can contain a drug to be provided to the patient <NUM>, and at a second end to the second pump line adaptor <NUM>. The syringe <NUM> may be coupled to a drug pump <NUM>. The drug pump <NUM> is a syringe pump that includes a clamping mechanism configured to retain the syringe <NUM> of the blood component set <NUM>. The drug pump <NUM> also includes a stepper motor configured to move the plunger of the syringe <NUM> along the axis of the syringe <NUM>. A shaft of the stepper motor is secured to the plunger in a manner such that when the stepper motor is operated in a first direction, the shaft forces the plunger into the syringe <NUM>, and when operated in a second direction, the shaft pulls the plunger out of the syringe <NUM>. The drug pump <NUM> can thus be used to inject a liquid drug (e.g., heparin) from the syringe <NUM> into the blood circuit <NUM> via the drug delivery line <NUM> during use, or to draw liquid from the blood circuit <NUM> into the syringe <NUM> via the drug delivery line <NUM> during use.

The various blood lines, the saline delivery line <NUM>, and the drug delivery line <NUM> can be formed of any of various different medical grade materials. Examples of such materials include PVC, polyethylene, polypropylene, silicone, polyurethane, high density polyethylene, nylon, ABS, acrylic, isoplast, polyisoprene, and polycarbonate.

The various blood lines, the saline delivery line <NUM>, and the drug delivery line <NUM> are typically retained within the module <NUM>. Various techniques can be used to secure the lines to the module <NUM>. For example, a carrier body with a series of apertures and recesses for capturing and retaining the various blood lines and components can be secured to the module <NUM> of the hemodialysis machine <NUM>. In some examples, mechanical attachment devices (e.g., clips or clamps) can be attached to a carrier body and used to retain the lines, and the carrier body can be attached to the module <NUM> of the hemodialysis machine <NUM>. As another example, the lines can be adhered to or thermally bonded to a carrier body, and the carrier body can be attached to the module <NUM> of the hemodialysis machine.

Referring to <FIG> and <FIG>, a method of preparing the hemodialysis system <NUM> for hemodialysis treatment will now be described. Before hemodialysis treatment is initiated, the blood component set <NUM> is connected to the hemodialysis machine <NUM>, as shown in <FIG>. For example, a first end of the arterial patient line <NUM> is attached to the pump line <NUM> via the first pump line adaptor <NUM> and a first end of the venous patient line <NUM> is attached to an exit port of the air release device <NUM>. Further, as depicted in <FIG>, before priming the hemodialysis system <NUM>, a patient end <NUM> of the arterial patient line <NUM> is coupled to the saline bag <NUM> via the saline delivery line <NUM> and a patient end <NUM> of the venous patient line <NUM> is attached to the drain apparatus <NUM> using the clip <NUM> of the drain apparatus. By attaching the venous patient line <NUM> to the drain apparatus <NUM> using the clip <NUM>, the patient end <NUM> of the venous patient line <NUM> can be positioned within the chamber <NUM> of the drain apparatus <NUM> without touching the walls of the inner funnel <NUM> of the drain apparatus <NUM>.

To begin priming the system <NUM>, saline is introduced from the saline bag <NUM> into the blood circuit <NUM> via the arterial patient line <NUM>. To draw the saline from the saline bag <NUM> through the arterial patient line <NUM> and into the blood circuit <NUM>, the blood pump <NUM> is turned on. The blood pump <NUM> draws the saline from the saline bag <NUM>, through saline delivery line <NUM> and the arterial patient line <NUM>, through the arterial pressure sensor <NUM>, and through the pump line <NUM> towards the dialyzer <NUM>. The saline flows into the dialyzer <NUM> via the dialyzer inlet line <NUM> and exits the dialyzer <NUM> via the dialyzer outlet line <NUM>. As the saline flows through the dialyzer outlet line <NUM> towards the air release device <NUM>, the saline passes through the venous pressure sensor <NUM>.

Next, the saline flows through an entry port of the air release device <NUM> and fills the air release device <NUM>. To fill the air release device <NUM>, the venous patient line <NUM>, which leads away from the air release device <NUM>, is clamped while the saline is forced into the air release device <NUM>. Air is forced out the top of the air release device <NUM> and through the vent assembly <NUM> as saline fills the air release device. Because the venous patient line <NUM> is still clamped at this time, the operation of the blood pump <NUM> builds a substantial amount of pressure within the blood air release device <NUM> via the vent assembly <NUM> of the air release device <NUM>. The saline does not pass through the vent assembly <NUM> because the membrane of the vent assembly <NUM> is hydrophobic.

Once the air release device <NUM> is filled with saline, the clamp is removed from the venous patient line <NUM> and saline flows through the venous patient line <NUM> towards the patient end <NUM> of the venous patient line <NUM>. Once the entire blood circuit <NUM> is filled with saline, any additional (e.g., excess) saline pumped through the blood component set <NUM> exits the patient end <NUM> of the venous patient line <NUM> and is captured by the chamber <NUM> of the drain apparatus <NUM>. The drain apparatus outlet valve <NUM> fluidly connected to the outlet line <NUM> of the drain apparatus <NUM> is open and the drain apparatus pump <NUM> is turned on during priming to draw saline collected from the venous patient line <NUM> by the drain apparatus <NUM> to the drain line <NUM> via the outlet line <NUM>.

The process of priming described above functions to remove air from within the blood circuit <NUM> and fills the blood circuit <NUM> with saline from the patient end <NUM> of the arterial patient line <NUM> to the patient end <NUM> of the venous patient line <NUM>. Once all air is out of the patient lines <NUM>, <NUM> and the blood circuit <NUM> is filled with saline, clamps are closed on the patient ends <NUM>, <NUM> of the patient lines <NUM>, <NUM>. Once clamped, the patient end <NUM> of the arterial patient line <NUM> is removed from the saline bag <NUM> and the patient end <NUM> of the venous patient line <NUM> is removed from the drain apparatus <NUM>.

After the initial priming, the patient ends <NUM>, <NUM> of the patient lines <NUM>, <NUM> can be connected together using a sterile recirculation connector and the saline contained within the blood circuit <NUM> can be recirculated through the blood circuit <NUM> away from the drain apparatus <NUM> until the patient <NUM> is ready for treatment.

Once the blood circuit <NUM> has been primed and the patient <NUM> is ready for treatment, the patient ends <NUM>, <NUM> of the arterial and venous patient lines <NUM>, <NUM> are connected to a patient <NUM>, as shown in <FIG>, and hemodialysis is initiated. Referring to <FIG> and <FIG>, a method of performing dialysis treatment using the hemodialysis system <NUM> will now be described.

During hemodialysis, blood is circulated through the blood circuit (i.e., the various blood lines and blood components, including the dialyzer <NUM>, of the blood component set <NUM>). At the same time, dialysate is circulated through the dialysate circuit (i.e., the various fluid lines and dialysate components, including the dialyzer <NUM>).

As shown in <FIG>, dialysate is generated by the dialysate circuit <NUM> and provided to the dialyzer <NUM> via fluid line of the dialysate circuit <NUM>. For example, referring to <FIG>, during hemodialysis, recirculation valve <NUM> is closed and water inlet valve <NUM> is open, and water used for generating dialysate is received by the hydraulic circuit <NUM> through the water inlet port <NUM>. The water passes through the heat exchanger <NUM>, the open water inlet valve <NUM>, and into the heating and deaeration chamber <NUM>. In some implementations, if the temperature of the water as detected by temperature control thermistor <NUM> of the heating sub-chamber 512A is below a threshold temperature, a heater <NUM> in heating sub-chamber 512B can be used to heat the water above the threshold temperature. The heated water passes through an aeration orifice <NUM> positioned between sub-chambers 512C, 512D to deaerate the flow of water.

During hemodialysis, the deaeration pump <NUM> pumps the flow of heated and deaerated water from deaeration and heating chambers <NUM> to the mixing chambers <NUM>, <NUM> via a fluid line. The flow of heated and deaerated water combines with a flow of acid concentrate provided by the acid concentrate pump <NUM> and a flow of bicarbonate provided by the bicarbonate pump <NUM>. As shown in <FIG>, the acid concentrate can be filtered by acid concentrate filter <NUM> prior to introduction of the concentrate into the flow of heated water. Similarly, bicarbonate provided by bicarbonate pump <NUM> can be filtered by bicarbonate filter <NUM> prior to introduction of the bicarbonate into the flow of heated water. The mixing chambers <NUM>, <NUM> receive the combined flow of heated water, acid concentrate, and bicarbonate and mix the fluids to generate a uniform dialysate fluid.

As previously discussed, the dialysate flows from mixing chamber <NUM> to the first chamber half <NUM>, <NUM> of one of the balancing devices <NUM>, <NUM> as controlled by valves <NUM> and <NUM>, respectively. As previously discussed, as fresh dialysate is flowing into one balancing device <NUM>, spent dialysate is flowing into the other balancing device <NUM>, and vice versa. As fresh dialysate flows into a first chamber halves <NUM>, <NUM>, spent dialysate is forced out the respective second chamber halves <NUM>, <NUM> through valves <NUM>, <NUM> via drain line <NUM>. Additionally, as spent dialysate flows into the second chamber halves <NUM>, <NUM> from dialyzer <NUM> via the air separation chamber <NUM>, the fresh dialysate in the respective first chamber halves <NUM>, <NUM> is forced out the respective balancing devices <NUM>, <NUM> through valves <NUM>, <NUM>, respectively, towards the dialyzer <NUM>.

Before the dialysate generated by the dialysate circuit <NUM> is provided to the dialyzer <NUM>, the dialysate passes through the dialysate filter <NUM> to remove any potential impurities in the dialysate. During hemodialysis, bypass valve <NUM> is closed and dialyzer inlet valve <NUM> is open to direct flow of dialysate from the dialysate filter <NUM> to the dialyzer <NUM>, and dialysate flows from the dialysate filter <NUM> to the dialyzer <NUM>. In addition, during hemodialysis, drain apparatus inlet valve <NUM> is closed to prevent dialysate from flowing into the drain apparatus during dialysis. If, during hemodialysis, pressure sensor <NUM> detects a build-up of fluid in the drain apparatus <NUM> for any reason (e.g., malfunction of valve <NUM>), valve <NUM> can be opened to empty the drain apparatus without interrupting the hemodialysis. In some implementations, the dialysate flows through a dialysate flow line indicator <NUM> prior to entering the dialyzer <NUM>.

During hemodialysis, spent dialysate exits the dialyzer <NUM> and passes through the dialysate circuit via the drain line <NUM>. As depicted in <FIG>, during hemodialysis, the dialyzer outlet valve <NUM> is open and spent dialysate is received from the dialyzer <NUM> by the drain line <NUM> and passes through a fluid line filter <NUM> and dialyzer outlet valve <NUM>. Fluid line filter <NUM> filters the spent dialysate exiting the dialyzer <NUM>. The spent dialysate exiting the dialyzer <NUM> passes through a pressure sensor <NUM> configured to measure the pressure of dialysate entering the drain line <NUM> from the dialyzer <NUM> and passes through a blood leak detector <NUM> configured to detect whether blood has leaked into the dialysate across the dialyzer <NUM> membrane.

Before entering the air separation chamber <NUM>, the spent dialysate flows through a post-dialyzer temperature thermistor <NUM> and a post-dialyzer conductivity cell <NUM> configured to regulate the temperature of the spent dialysate.

As previously discussed, the spent dialysate is received by the air separation chamber <NUM>, which is configured to vent off any air contained in the dialysate through valve <NUM>. The dialysate flow pump <NUM> draws dialysate from the air separation chamber <NUM>, through a drain check valve <NUM>, and into one of the second chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM> through one of valves <NUM> and <NUM>, respectively. Drain check valve <NUM> is fluidly coupled to the drain line <NUM> downstream of the dialysate flow pump <NUM> and is configured to prevent fluid from flowing backwards along the drain line <NUM> towards the dialysate flow pump <NUM>.

As fresh dialysate is provided to one of the first chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM>, the spent dialysate in the respective second chamber half is forced out the respective balancing device <NUM>, <NUM> along the drain line <NUM> to the heat exchanger <NUM>.

During hemodialysis, the ultrafiltration pump <NUM> operates simultaneously with the dialysate flow pump <NUM> to generate an increased vacuum pressure within the drain line <NUM> connecting the air separation chamber <NUM> to the dialyzer <NUM>, and thus creates increased vacuum pressure within the dialyzer <NUM>. As a result of this increased vacuum pressure, additional fluid is pulled from the blood circuit <NUM> into the dialysate circuit <NUM> across the semi-permeable structure (e.g., semi-permeable membrane or semi-permeable microtubes) of the dialyzer <NUM>. This additional fluid is passed along the drain line <NUM> through an ultrafiltration pump filter <NUM> downstream of the air separation chamber <NUM> and through an ultrafiltration check valve <NUM>, and to the drain line <NUM> and the heater. The ultrafiltration check valve <NUM> prevents fluid from flowing backwards along the ultrafiltration line <NUM> towards the ultrafiltration pump <NUM>.

After passing through the heat exchanger <NUM>, spent dialysate exits the dialysate circuit through the drain line <NUM> and travels to a drain outside the hemodialysis machine <NUM>.

Referring to <FIG>, during hemodialysis, the patient's <NUM> blood is drawn from the patient end <NUM> of the arterial patient line <NUM> into the blood circuit <NUM> by the blood pump <NUM>. In some implementations, prior to providing the patient's <NUM> blood the dialyzer <NUM>, the flow of blood is combined with saline provided by saline delivery line <NUM> and one or more drugs (e.g., heparin) provided from syringe <NUM> by drug pump <NUM> through the drug delivery line <NUM>. The combined flow enters the dialyzer <NUM> through dialyzer inlet line <NUM>.

After passing through the dialyzer <NUM>, the patient's <NUM> filtered blood exits the dialyzer <NUM> and enters the blood circuit <NUM> through the dialyzer outlet line <NUM>. The blood flows through the venous pressure sensor <NUM> to the air release device <NUM>. As previously discussed, the air release device <NUM> removes any air contained within the filtered blood through the vent assemble <NUM>.

After flowing through the air release device <NUM>, the deaerated, filtered blood flows through the venous patient line <NUM> to an air bubble detector <NUM>. As previously discussed, the air bubble detector is configured to detect air bubbles contained in the flow of blood. After passing through the air bubble detector <NUM>, the filtered blood passes through an occluder <NUM>. As previously discussed, the occluder <NUM> can, for example, be connected to the air bubble detector <NUM> so that the occluder <NUM> can be activated when the air bubble detector <NUM> detects an air bubble within the venous patient line <NUM>. If no air bubbles are detected by the air bubble detector <NUM>, the blood flows through the occluder <NUM> to the patient end <NUM> of the venous patient line <NUM>, and into the patient.

After the dialysis treatment has been performed, blood contained within the blood circuit <NUM> is reinfused (i.e. rinsed back) to the patient <NUM>. To perform reinfusion, the arterial patient line <NUM> is clamped, and the patient end <NUM> of the arterial patient line <NUM> is attached to the saline bag <NUM>. The arterial patient line <NUM> is then unclamped, and saline is pumped from the saline bag <NUM> through the arterial patient line <NUM> by the blood pump <NUM>. The saline is then pumped throughout the entire blood circuit <NUM> to the patient end <NUM> of the venous patient line <NUM> to push any blood remaining in the blood circuit <NUM> back to the patient <NUM> and fill the circuit <NUM> with saline.

Once a desired amount of the blood contained within the blood circuit <NUM> has been reinfused back to the patient <NUM>, the patient lines <NUM>, <NUM> are clamped and the venous patient line <NUM> is removed from the patient <NUM>. As depicted in <FIG>, the patient end <NUM> of the venous patient line <NUM> is attached to the drain apparatus <NUM> using the clip <NUM>. By attaching the venous patient line <NUM> to the drain apparatus <NUM> using the clip <NUM>, the patient end <NUM> of the venous patient line <NUM> is positioned within the chamber <NUM> of the drain apparatus <NUM> without touching the walls of the inner funnel <NUM>. The blood pump <NUM> draws the saline from the saline bag <NUM> through the arterial patient line <NUM> and circulates the saline throughout all components of the blood circuit <NUM>. After circulating through the blood circuit <NUM>, the saline exits the patient end <NUM> of the venous patient line <NUM> and collects in the chamber <NUM> of the drain apparatus <NUM>. The drain apparatus outlet valve <NUM> is open and the drain apparatus pump <NUM> is turned on to draw the saline collected from the venous patient line <NUM> by the drain apparatus <NUM> to the drain line <NUM> via the outlet line <NUM>. Saline is continuously pumped through the blood circuit <NUM> until all remaining patient fluids have been flushed from the blood circuit <NUM> into the drain apparatus <NUM>. In some cases, for example, saline is pumped through the blood circuit <NUM> until the saline bag <NUM> is empty.

After completing the patient's treatment and flushing the blood circuit <NUM>, the blood component set <NUM> is disconnected from the module <NUM> of the hemodialysis machine <NUM> and discarded. Dialysate contained within the dialysate circuit is pumped to a drain outside the hemodialysis machine via the drain line <NUM> using the dialysate flow pump <NUM> and/or the ultrafiltration pump <NUM>. Following treatment, the dialysate circuit and drain apparatus are disinfected in preparation for a subsequent treatment.

Referring to <FIG> and <FIG>, a method of disinfecting the dialysate circuit <NUM> and drain apparatus <NUM> will now be described. As previously discussed, after completing dialysis treatment and flushing the blood circuit <NUM>, the venous patient line <NUM> is removed from the drain apparatus <NUM> and discarded with the rest of the blood component set <NUM>. In some implementations, during disinfection, one or more of the acid concentrate port <NUM> and bicarbonate port <NUM> of the dialysate circuit are removed from the acid concentrate and bicarbonate sources and are connected to a source of chemical disinfectant fluid concentrate. Prior to disinfection of the dialysate circuit <NUM> and the drain apparatus <NUM>, the lid <NUM> of the drain apparatus <NUM> is closed to form a liquid-tight seal with the chamber <NUM> of the drain apparatus <NUM> and the drain apparatus outlet valve <NUM> on the outlet line <NUM> is closed.

Once the lid <NUM> of the drain apparatus is closed and the drain apparatus outlet valve <NUM> is closed, sterilization of the dialysate circuit <NUM> and drain apparatus <NUM> may begin. To disinfect the dialysate circuit <NUM> and drain apparatus <NUM>, water is pumped into the dialysate circuit <NUM> from the water inlet port <NUM> to the heat exchanger <NUM>.

Water heated by heat exchanger <NUM> flows from the heat exchanger <NUM> through the recirculation valve <NUM> to the heating and deaeration chamber <NUM>. The deaeration and heating chamber <NUM> is configured to heat and deaerate water received by the dialysate circuit <NUM> through the water port <NUM> for disinfection. The water is heated to a desired temperature in the heating and deaeration chamber <NUM>.

One or more of the acid concentrate pump <NUM> and the bicarbonate pump <NUM> pump chemical disinfectant concentrate into the flow of heated water exiting the heating and deaeration chamber <NUM>. The combined flow of heated water and chemical disinfectant concentrate are provided to the mixing chambers <NUM>, <NUM> to mix the heated water and disinfectant concentrate to create a homogenous disinfectant fluid.

Disinfectant fluid exits mixing chamber <NUM> and flows through valves <NUM> and <NUM> to the one of the first chamber halves <NUM>, <NUM> of the one of the balancing devices <NUM>, <NUM>. As with the flow dialysate solution, as disinfectant fluid flows through the first chamber half <NUM> of one balancing device <NUM>, disinfectant fluid flows into the second chamber half <NUM> of the other balancing device <NUM>, and vice versa, as controlled by valves <NUM> through <NUM>. Further, as with the flow of dialysate solution, as disinfectant fluid flows into the first chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM>, disinfectant fluid is simultaneously forced out of the second chamber halves <NUM>, <NUM>, and vice versa.

The disinfectant fluid flowing out of the first chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM> flows through a conductivity cell <NUM> and a temperature monitor thermistor <NUM> towards the dialysate filter <NUM>. During the initial flow of disinfectant fluid through the dialysate circuit <NUM>, the bypass valve <NUM> is open and the drain apparatus inlet valve <NUM> and the vent valve <NUM> are closed to direct disinfectant fluid from the dialysate filter <NUM> towards the post-dialyzer temperature thermistor <NUM> and the post-dialyzer conductivity cell <NUM> and through the air separation chamber <NUM>.

Disinfectant fluid is then pumped from the air separation chamber <NUM> to one of the second chamber halves <NUM>, <NUM> of one of the balancing devices <NUM>, <NUM> through valves <NUM> and <NUM>, respectively, by one or more of the dialysate flow pump <NUM> and the ultrafiltration pump <NUM>. As disinfectant fluid flows into the first chamber halves <NUM>, <NUM>, the disinfectant fluid in the second chamber halves <NUM>, <NUM> flows out of the second chamber halves <NUM>, <NUM> through valves <NUM>, <NUM>, respectively via the drain line <NUM>. During disinfection, the drain valve <NUM> is closed, and disinfectant fluid exiting second chamber halves <NUM>, <NUM> flows through the drain line <NUM> to the heat exchanger <NUM> and then back down through recirculation valve <NUM> via a fluid line.

Water is continuously added the dialysate circuit <NUM> via water inlet port <NUM> in order to produce disinfectant fluid to circulate throughout the entire dialysate circuit <NUM>. During disinfection, water inlet pressure regulator <NUM> monitors the fluid pressure of the fluid line extending from the water inlet port <NUM>, and whenever the water inlet pressure regulator <NUM> detects that a threshold pressure indicating the entire dialysate circuit is filled with disinfectant fluid has been reached, bypass valve <NUM> is closed and drain apparatus inlet valve <NUM> is opened. By closing bypass valve <NUM> and opening drain apparatus inlet valve <NUM>, disinfectant fluid exiting the dialysate filter <NUM> is directed to the drain apparatus <NUM> via the inlet line <NUM> coupled to the outlet of the dialysate filter <NUM>.

Still referring to <FIG> and <FIG>, disinfectant fluid flows through the open drain apparatus inlet valve <NUM> and the inlet line <NUM> to the inlet port <NUM> of the drain apparatus <NUM>, and flows up into and fills the annular channel <NUM> between the inner funnel <NUM> and outer funnel <NUM>. Once the disinfectant fluid reaches the top of the annular channel <NUM>, the curved upper lip <NUM> of the outer funnel <NUM> forces the solution over the annular surface <NUM> of the inner funnel <NUM>, causing the disinfectant fluid to run down the surface of the inner funnel <NUM>. Because the annular channel <NUM> completely surrounds the inner funnel, the disinfectant fluid is evenly distributed across the surface of the inner funnel <NUM> and washes the entire surface of the inner funnel <NUM>.

During this portion of the disinfection, the drain apparatus outlet valve <NUM> is closed to allow the chamber <NUM> of the drain apparatus <NUM> to be filled with disinfectant fluid. In addition, during this portion of disinfection, the pump <NUM> is in a position to prevent disinfectant fluid from flowing to the drain line <NUM> via the outlet line <NUM> in order to allow the chamber <NUM> of the drain apparatus <NUM> to be filled with disinfectant fluid. As disinfectant fluid enters the chamber <NUM> of the drain apparatus <NUM> via the inlet line <NUM> and annular channel <NUM>, the chamber <NUM> begins to fill with disinfectant fluid and any air in the chamber <NUM> exits out the vent <NUM> and hydrophobic filter <NUM> coupled to the closed lid <NUM> of the drain apparatus <NUM>. The hydrophobic filter <NUM> attached to and covering the vent <NUM> prevents disinfectant fluid from passing through the vent <NUM>. This arrangement of the vent <NUM> and hydrophobic filter <NUM> allows substantially all of the air in the chamber <NUM> to be displaced by disinfectant fluid, allowing for almost the entire chamber <NUM> of the drain apparatus <NUM> to be filled with disinfectant fluid when the outlet valve <NUM> is closed.

The pressure sensor <NUM> coupled to the outlet line <NUM> of the drain apparatus <NUM> monitors the fluid pressure in the chamber <NUM> during disinfection. Once the pressure sensor <NUM> detects that the pressure in the chamber <NUM> has reached a threshold pressure indicating that the chamber <NUM> is filled with fluid, drain apparatus inlet valve <NUM> is closed to prevent any additional disinfectant fluid from entering the chamber <NUM> via the inlet line <NUM>. In some implementations, once the pressure sensor <NUM> detects that the pressure in the chamber <NUM> has reached a threshold pressure indicating that the chamber <NUM> is filled with fluid, a signal is sent to close the water inlet valve <NUM> in order to prevent additional water from being added to the dialysate circuit <NUM> via the water inlet port <NUM> and stop the production of disinfectant fluid.

Once the chamber <NUM> is full of disinfectant fluid, the drain apparatus outlet valve <NUM> remains closed for a predetermined amount of time to allow the disinfectant fluid to dwell in the chamber <NUM> for a predetermined amount of time. In some implementations, the disinfectant fluid dwells in the chamber <NUM> for at least <NUM> minutes (e.g., at least <NUM> minutes, <NUM> minutes to <NUM> minutes).

After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened. The drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>. The drain apparatus pump <NUM> continues to run until all of the disinfectant fluid is pumped out of the drain apparatus <NUM> to the drain line <NUM>.

Similarly, once the disinfectant fluid has recirculated through the dialysate circuit for a predetermined amount of time, the recirculation valve <NUM> is closed and the drain valve <NUM> is opened to direct the disinfectant fluid through the drain line <NUM> towards a drain. In some implementations, the dialysate flow circuit pumps the disinfectant fluid through the balancing devices <NUM>, <NUM> and along the drain line <NUM> through drain valve <NUM>. In some implementations, the drain valve <NUM> and the drain apparatus outlet valve <NUM> are opened at or near the same time, and the dialysate circuit <NUM> and drain apparatus <NUM> are drained of disinfectant fluid simultaneously.

While certain embodiments have been described above, other embodiments are possible.

<FIG>, for example, is a schematic showing an alternate arrangement of the dialysate circuit <NUM> and the drain apparatus <NUM> of the hemodialysis machine <NUM>. As shown in <FIG>, the drain apparatus <NUM> does not include a drain apparatus pump (e.g. drain apparatus pump <NUM> of <FIG>) along the outlet line <NUM> between the outlet port <NUM> of the drain apparatus <NUM> and the drain line <NUM>. In such instances, drain apparatus <NUM> is configured such that the fluid contained within the chamber <NUM> of the drain apparatus <NUM> is gravity drained to the drain line <NUM> via the outlet line <NUM> whenever the drain apparatus valve <NUM> is open. For example, during disinfection of the drain apparatus <NUM>, disinfectant fluid contained in the chamber <NUM> of the drain apparatus <NUM> drains through the outlet line <NUM> to the drain line <NUM> by gravity whenever the drain apparatus outlet valve <NUM> is opened.

In some embodiments, the drain apparatus includes a drain pump along the outlet line <NUM> (such as drain pump <NUM>), but does not include a drain valve (e.g., drain valve <NUM> of <FIG>, <FIG>) along the outlet line <NUM> between the outlet port <NUM> of the drain apparatus <NUM> and the drain line <NUM>. In such instances, drain pump <NUM> acts to control the flow of fluid out of the chamber <NUM> via the outlet line <NUM>. For example, during disinfection of the drain apparatus <NUM>, the drain pump <NUM> can be configured to block fluid from flowing through the outlet line <NUM> to the drain until the pump <NUM> is activated to pump the fluid from the chamber <NUM> to the drain line <NUM> via the outlet line <NUM>.

<FIG> is a schematic showing an alternate arrangement of the dialysate circuit <NUM> and drain apparatus <NUM> of the hemodialysis machine <NUM>. As shown in <FIG>, the inlet line <NUM> of the drain apparatus <NUM> is fluidly connected to the fluid line downstream of the dialysate filter <NUM> and the outlet line <NUM> of the drain apparatus <NUM> is fluidly connected to a portion of the drain line <NUM> of the dialysate circuit <NUM> upstream of the dialysate flow pump <NUM>. In this arrangement, as depicted in <FIG>, the drain apparatus <NUM> does not include a drain apparatus pump (e.g. drain apparatus pump <NUM> of <FIG>) along the outlet line <NUM>. Instead, the negative pressure created by dialysate flow pump <NUM> of the dialysate circuit <NUM> is used to draw fluid contained within the chamber <NUM> of the drain apparatus <NUM> out of the drain apparatus <NUM> through the drain apparatus outlet valve <NUM> via the outlet line <NUM>. Using this arrangement, fluid contained within the chamber <NUM> of the drain apparatus <NUM> is drained through the outlet line <NUM> and provided to the dialysate circuit <NUM> downstream of the air separation chamber <NUM>. The dialysate flow pump <NUM> is then used to pump the fluid away from the drain apparatus <NUM> through the drain line <NUM> to one of the second chamber halves <NUM>, <NUM> of one of the balancing devices <NUM>, <NUM> and on to the drain, as described above. For example, using this arrangement during disinfection of the drain apparatus <NUM>, the drain apparatus outlet valve <NUM> is open and the dialysate flow pump <NUM> draws the disinfectant fluid contained in the chamber <NUM> of the drain apparatus <NUM> through the outlet line <NUM> to a portion of the drain line <NUM> of the dialysate circuit <NUM> downstream of the air separation chamber <NUM>. The dialysate flow pump <NUM> then flows the disinfectant fluid to one of the second chamber halves <NUM>, <NUM> of one of the balancing devices <NUM>, <NUM> via the drain line <NUM>. Finally, the disinfectant fluid exits the second chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM> and flows to a drain via the drain line <NUM>.

Similarly, in some implementations, the outlet line <NUM> of the drain apparatus <NUM> can be fluidly connected to a portion of the drain line <NUM> of the dialysate circuit <NUM> upstream of the ultrafiltration pump <NUM> of the dialysate circuit. In this arrangement, negative pressure created by ultrafiltration pump <NUM> of the dialysate circuit <NUM> is used to draw fluid contained within the chamber <NUM> of the drain apparatus <NUM> out of the drain apparatus <NUM> through the drain apparatus outlet valve <NUM> via the outlet line <NUM>. The ultrafiltration pump <NUM> is then used to pump the fluid away from the drain apparatus <NUM> through the drain line <NUM> to one of the second chamber halves <NUM>, <NUM> of the one of balancing devices <NUM>, <NUM> and on to the drain, as described above.

Additionally, while the inlet line <NUM> of the drain apparatus <NUM> has been described as being fluidly connected to the fluid line downstream of the dialysate filter <NUM>, the inlet line <NUM> can alternatively be coupled to a fluid line of the dialysate circuit <NUM> at any other point within the dialysate circuit <NUM> upstream of the dialyzer <NUM>.

While the drain apparatus <NUM> is described as having a vent <NUM> and hydrophobic filter <NUM> to allow for complete filling of the chamber <NUM> of the drain apparatus <NUM>, other configurations of the drain apparatus may alternatively be provided to allow for complete filling of the chamber <NUM>. <FIG> depict cross-section views of alternate drain apparatuses for the hemodialysis system of <FIG>.

As depicted in <FIG>, in some implementations, rather than having a vent and hydrophobic filter (e.g., vent <NUM> and hydrophobic filter <NUM> of <FIG>), the lid <NUM> of the drain apparatus can include a plurality of vents or holes <NUM> through the lid <NUM>. In this arrangement, the lid <NUM> of the drain apparatus <NUM> is liquid-tight when closed and fluid contained within the chamber <NUM> of the drain apparatus can exit through the holes <NUM> in the lid <NUM>. This arrangement of the holes <NUM> in the lid <NUM> of the drain apparatus <NUM> allows all of the air in the chamber <NUM> of the apparatus <NUM> to be displaced by disinfectant fluid during disinfection, allowing for the entire chamber <NUM> to be filled with disinfectant fluid when the outlet valve <NUM> is closed. In some implementations, in order to fill the chamber <NUM> of the drain apparatus <NUM> with disinfectant fluid during disinfection, a pressure sensor <NUM> coupled to the outlet line <NUM> monitors the fluid pressure in the chamber <NUM> of the drain apparatus <NUM> during disinfection, and once the pressure sensor <NUM> detects that the pressure in the chamber <NUM> has reached a threshold pressure indicating that the chamber <NUM> is filled with fluid, drain apparatus inlet valve <NUM> is closed to prevent additional disinfectant fluid from entering the chamber <NUM> via the inlet line <NUM>. Once the chamber <NUM> is filled with disinfectant fluid, the disinfectant fluid is allowed to dwell in the chamber <NUM> for a predetermined amount of time. In some implementations, once the pressure sensor <NUM> detects that the pressure in the chamber <NUM> has reached a threshold pressure indicating that the chamber <NUM> is filled with fluid, a signal is sent to close the water inlet valve <NUM> in order to prevent additional water from being added to the dialysate circuit <NUM> via the water inlet port <NUM> and stop the production of disinfectant fluid. After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened and the drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>.

As depicted in <FIG>, in some implementations, the lid <NUM> of the drain apparatus <NUM> is not liquid-tight when in a closed position and the chamber <NUM> of the drain apparatus <NUM> is filled with disinfectant fluid during disinfection by metering the flow of disinfectant fluid into inlet line <NUM> of the drain apparatus <NUM> using the balancing devices <NUM>, <NUM> of the dialysate circuit <NUM>. For example, once the drain apparatus inlet valve <NUM> is opened during disinfection, the amount of disinfectant fluid exiting the balancing devices <NUM>, <NUM> towards the drain apparatus <NUM> can be controlled to provide the exact amount of disinfectant fluid required to fill the fluid line between the balancing devices <NUM>, <NUM> and the inlet line <NUM>, the inlet line <NUM>, and the chamber <NUM> of the drain apparatus <NUM>. In this arrangement, as disinfectant fluid enters the chamber <NUM>, an equal amount of air contained in the chamber <NUM> exits the chamber <NUM> around the non-liquid-tight lid <NUM>. In some implementation, the lid <NUM> of the drain apparatus <NUM> includes vents or holes (such as holes <NUM> of <FIG>). In some examples, each stroke of the balancing devices <NUM>, <NUM> provides <NUM> ccs of disinfectant fluid to the drain apparatus <NUM> via the inlet line <NUM>, and a calculated number of strokes of the balancing devices <NUM>, <NUM> are performed in order to provide the amount of disinfectant fluid necessary to fill the chamber <NUM> of the drain apparatus <NUM>. Once the chamber <NUM> is filled with disinfectant fluid, drain apparatus outlet valve <NUM> remains closed to allow the disinfectant fluid to dwell in the chamber <NUM> for a predetermined amount of time. After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened and the drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>.

Referring to <FIG>, in some implementations, the lid <NUM> of the drain apparatus <NUM> is not liquid-tight when in a closed position and the drain apparatus <NUM> includes an ultrasound sensor <NUM> coupled to the outer funnel <NUM> is configured to detect the liquid level <NUM> inside the chamber <NUM> of the drain apparatus <NUM>. For example, during disinfection, the level of disinfectant fluid in the chamber <NUM> of the drain apparatus <NUM> is monitored by the ultrasound sensor <NUM>. During disinfection, drain apparatus outlet valve <NUM> is closed and disinfectant fluid is provided to the chamber <NUM> of the drain apparatus <NUM> via the inlet line <NUM>. In this arrangement, as disinfectant fluid enters the chamber <NUM>, an equal amount of air contained in the chamber <NUM> exits the chamber <NUM> around the non-liquid-tight lid <NUM>. In some implementation, the lid <NUM> of the drain apparatus <NUM> includes vents or holes (such as holes <NUM> of <FIG>). Once the ultrasound sensor <NUM> detects that level <NUM> of disinfectant fluid is at or near the top of the chamber <NUM>, the drain apparatus valve <NUM> is closed to prevent any additional disinfectant fluid from entering the chamber <NUM> of the drain apparatus <NUM> and the disinfectant fluid is allowed to dwell in the chamber <NUM> for a predetermined amount of time. In some implementations, once the ultrasound sensor <NUM> detects that the liquid level <NUM> is at or near the top of the chamber <NUM> such that the chamber <NUM> is filled with fluid, a signal is sent to close the water inlet valve <NUM> in order to prevent additional water from being added to the dialysate circuit <NUM> via the water inlet port <NUM> and stop the production of disinfectant fluid. After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened and the drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>.

Referring to <FIG>, in some implementations, the lid <NUM> of the drain apparatus <NUM> is not liquid-tight when in a closed position and one or more electrodes <NUM> are positioned within the chamber <NUM> of the drain apparatus and configured to detect the level <NUM> of chemical disinfectant fluid inside the chamber <NUM> of the drain apparatus <NUM>. For example, the one or more electrodes <NUM> may be attached to the top of the inner funnel <NUM> of the drain apparatus and configured to interact with disinfectant fluid. During disinfection, drain apparatus outlet valve <NUM> is closed and disinfectant fluid is provided to the chamber <NUM> of the drain apparatus <NUM> via the inlet line <NUM>. In this arrangement, as disinfectant fluid enters the chamber <NUM>, an equal amount of air contained in the chamber <NUM> exits the chamber <NUM> around the non-liquid-tight lid <NUM>. In some implementation, the lid <NUM> of the drain apparatus <NUM> includes vents or holes (such as holes <NUM> of <FIG>). Once the chemical disinfectant fluid is at or near the top of the chamber <NUM>, the chemicals in the disinfectant fluid will interact with the one or more electrodes <NUM> located near the top of the chamber <NUM>, indicating that the chamber <NUM> is full of disinfectant fluid. In some implementations, once the one or more electrodes <NUM> detect that the level <NUM> of disinfectant fluid is at or near the top of the chamber <NUM>, the drain apparatus valve <NUM> is closed to prevent any additional disinfectant fluid from entering the chamber <NUM> of the drain apparatus and the disinfectant fluid is allowed to dwell in the chamber <NUM> for a predetermined amount of time. In some implementations, once the one or more electrodes <NUM> detect that the level <NUM> of disinfectant fluid is at or near the top of the chamber <NUM>, a signal is sent to close the water inlet valve <NUM> in order to prevent additional water from being added to the dialysate circuit <NUM> via the water inlet port <NUM> and stop the production of disinfectant fluid. After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened and the drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>. Any of various suitable electrodes can be used to detect fluid levels, such as an in-line tube electrode with an optical slot, a conductive rod probe, etc..

As depicted in <FIG>, in some implementations, the lid <NUM> of the drain apparatus <NUM> is not liquid-tight when in a closed position and the drain apparatus <NUM> includes an ultrasonic transmitter <NUM> and ultrasonic receiver <NUM> configured to detect the liquid level <NUM> inside the chamber <NUM> of the drain apparatus <NUM>. In this arrangement, as disinfectant fluid enters the chamber <NUM>, an equal amount of air contained in the chamber <NUM> exits around the non-liquid-tight lid <NUM>. In some implementation, the lid <NUM> of the drain apparatus <NUM> includes vents or holes (such as holes <NUM> of <FIG>). As shown in <FIG>, the ultrasonic transmitter <NUM> and ultrasonic receiver <NUM> can be coupled to the inside surface <NUM> of lid <NUM> of the drain apparatus <NUM> facing towards the chamber <NUM> of the drain apparatus <NUM> when the lid <NUM> is in a closed position. During disinfection, drain apparatus outlet valve <NUM> is closed, lid <NUM> is closed over the chamber <NUM>, disinfectant fluid is provided to the chamber <NUM> of the drain apparatus <NUM> via the inlet line <NUM>, and the ultrasonic transmitter <NUM> transmits soundwaves through the lid <NUM> to the chamber <NUM>. The soundwaves transmitted by ultrasonic transmitter <NUM> bounce off the surface of liquid in the chamber <NUM> and are received by the ultrasonic receiver <NUM>. Based on the intensity of the soundwaves received by the ultrasonic receiver <NUM>, the level <NUM> of disinfectant fluid in the chamber <NUM> of the drain apparatus <NUM> can be determined. Once the sound waves received by the ultrasonic receiver <NUM> indicate that level <NUM> of disinfectant fluid is at or near the top of the chamber <NUM>, the drain apparatus valve <NUM> is closed to prevent any additional disinfectant fluid from entering the chamber <NUM> of the drain apparatus. In some implementations, once the sound waves received by the ultrasonic receiver <NUM> indicate that the liquid level <NUM> is at or near the top of the chamber <NUM>, a signal is sent to close the water inlet valve <NUM> in order to prevent additional water from being added to the dialysate circuit <NUM> via the water inlet port <NUM> and stop the production of disinfectant fluid. After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened and the drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>. Any of various suitable ultrasonic transmitters and receivers can be used to detect fluid levels, such as an ultrasonic gap sensor.

Referring to <FIG>, in some implementations, the lid <NUM> of the drain apparatus <NUM> is not liquid-tight when in a closed position and the drain apparatus <NUM> includes a light transmitter <NUM> and light receiver <NUM> configured to detect the liquid level <NUM> inside the chamber <NUM> of the drain apparatus <NUM>. In this arrangement, as disinfectant fluid enters the chamber <NUM>, an equal amount of air contained in the chamber <NUM> exits around the non-liquid-tight lid <NUM>. In some implementation, the lid <NUM> of the drain apparatus <NUM> includes vents or holes (such as holes <NUM> of <FIG>). As shown in <FIG>, the light transmitter <NUM> and light receiver <NUM> can be coupled to the inside surface <NUM> of lid <NUM> of the drain apparatus <NUM> facing towards the chamber <NUM> of the drain apparatus <NUM> when the lid <NUM> is in a closed position. During disinfection, drain apparatus outlet valve <NUM> is closed, lid <NUM> is closed over the chamber <NUM>, disinfectant fluid is provided to the chamber <NUM> of the drain apparatus <NUM> via the inlet line <NUM>, and the light transmitter <NUM> transmits light waves into the chamber <NUM>. The light waves transmitted by light transmitter <NUM> bounce off the surface of liquid in the chamber <NUM> and are received by the light receiver <NUM>. Based on the intensity of the light waves received by the light receiver <NUM>, the level <NUM> of disinfectant fluid in the chamber <NUM> of the drain apparatus <NUM> can be determined. Once the light waves received by the light receiver <NUM> indicate that level <NUM> of disinfectant fluid is at or near the top of the chamber <NUM>, the drain apparatus valve <NUM> is closed to prevent any additional disinfectant fluid from entering the chamber <NUM> of the drain apparatus. In some implementations, once the light waves received by the light receiver <NUM> indicate that the liquid level <NUM> is at or near the top of the chamber <NUM>, a signal is sent to close the water inlet valve <NUM> in order to prevent additional water from being added to the dialysate circuit <NUM> via the water inlet port <NUM> and stop the production of disinfectant fluid. After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened and the drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>. Any of various suitable light transmitters and receivers can be used to detect fluid levels, such as an optical switch sensor.

Referring to <FIG>, in some implementations, the lid <NUM> of the drain apparatus <NUM> is not liquid-tight when in a closed position and the drain apparatus <NUM> includes a level sensor <NUM> coupled to the drain apparatus <NUM>. Level sensor <NUM> is configured to detect the liquid level <NUM> inside the chamber <NUM> of the drain apparatus <NUM>. For example, during disinfection, the level of disinfectant fluid in the chamber <NUM> of the drain apparatus <NUM> is monitored by the level sensor <NUM>. During disinfection, drain apparatus outlet valve <NUM> is closed and disinfectant fluid is provided to the chamber <NUM> of the drain apparatus <NUM> via the inlet line <NUM>. In this arrangement, as disinfectant fluid enters the chamber <NUM>, an equal amount of air contained in the chamber <NUM> exits the chamber <NUM> around the non-liquid-tight lid <NUM>. In some implementations, the lid <NUM> of the drain apparatus <NUM> includes vents or holes (such as holes <NUM> of <FIG>). Once the level sensor <NUM> detects that level <NUM> of disinfectant fluid is at or near the top of the chamber <NUM>, the drain apparatus valve <NUM> is closed to prevent any additional disinfectant fluid from entering the chamber <NUM> of the drain apparatus <NUM> and the disinfectant fluid is allowed to dwell in the chamber <NUM> for a predetermined amount of time. In some implementations, once the level sensor <NUM> detects that the liquid level <NUM> is at or near the top of the chamber <NUM> such that the chamber <NUM> is filled with fluid, a signal is sent to close the water inlet valve <NUM> in order to prevent additional water from being added to the dialysate circuit <NUM> via the water inlet port <NUM> and stop the production of disinfectant fluid. After the disinfectant fluid has dwelled in the chamber <NUM> for the predetermined amount of time, the drain apparatus outlet valve <NUM> is opened and the drain apparatus pump <NUM> draws the disinfectant fluid out of the chamber <NUM> through outlet port <NUM> and the open drain apparatus outlet valve <NUM> to the drain line <NUM> via the outlet line <NUM>. Any of various suitable level sensors can be used, such as a level switch, a magnetic level switch, a magnetic float sensor, a pneumatic level sensor, an electrode level sensor, a conductivity level sensor, etc..

While the methods described above for disinfecting the drain apparatus <NUM> involve allowing the disinfectant fluid to dwell in the chamber <NUM> of the drain apparatus <NUM> for a predetermined amount of time, other techniques can alternatively or additionally be used. In some implementations, for example, once the chamber <NUM> of drain apparatus <NUM> is filled with disinfectant fluid (as determined using the methods above), the drain apparatus outlet valve <NUM> is opened to allow disinfectant fluid to flow through the outlet line <NUM> to the drain line <NUM>, and additional disinfectant fluid is simultaneously provided to the chamber <NUM> via the inlet line <NUM>. In some implementations, once the chamber <NUM> is filled with disinfectant fluid and the outlet valve <NUM> has been opened, the dialysate circuit <NUM> pumps disinfectant fluid to the chamber <NUM> via the inlet line <NUM> at a rate sufficient to maintain the disinfectant fluid level <NUM> in chamber <NUM> (i.e., keep the chamber filled with disinfectant fluid). This "continuous flow" method of draining and simultaneously filling of the chamber <NUM> of the drain apparatus <NUM> can be performed for a predetermined amount of time to ensure that the chamber <NUM> is properly disinfected. In some implementations, the disinfectant fluid continuously flows through and fills the chamber <NUM> for at least <NUM> minutes (e.g., at least <NUM> minutes, <NUM> to <NUM> minutes). In some examples, after the disinfectant fluid has been flowing and filling the chamber <NUM> for the predetermined amount of time, the drain apparatus inlet valve <NUM> is closed and the solution contained in the chamber <NUM> of the drain apparatus <NUM> exits the chamber <NUM> through drain apparatus outlet valve <NUM> via the outlet line <NUM> to the drain line <NUM>.

Further, while the disinfectant fluid used to disinfect the dialysate circuit <NUM> and the drain apparatus <NUM> has been described as including a chemical disinfectant concentrate, the disinfectant fluid can alternatively be composed of hot water alone (i.e., without the addition of chemical disinfectant concentrate). In some examples, the disinfectant fluid is heated to a temperature of at least <NUM>.

While the hydrophobic filter <NUM> of the drain apparatus <NUM> has been described as being arranged within the vent <NUM> of the drain apparatus, the hydrophobic filter <NUM> can alternatively be incorporated into the lid <NUM> of the drain apparatus <NUM>. For example, the lid <NUM> can include an opening therethrough and the hydrophobic filter <NUM> can be arranged within the opening in the lid <NUM>.

While the lid <NUM> has been described as being attached to the drain apparatus <NUM> using a hinge <NUM>, the lid <NUM> can be attached to the drain apparatus <NUM> using alternative attachment mechanisms, such as clips, threads, an injection molded attachment, magnets, etc. In some examples, the lid <NUM> is attached to the drain apparatus <NUM> along a pivoting axis such that that lid <NUM> can be pivoted along to the axis to cover the drain apparatus <NUM>. In some implementations, the lid <NUM> is pivoted about an axis by a stepper motor attached to the lid <NUM>. In some embodiments, the lid <NUM> may be unattached from the drain apparatus <NUM> and can be placed on top of the apparatus <NUM> to seal the chamber <NUM>, such as during disinfection of the chamber.

While the methods above involve attaching only the venous patient line <NUM> to the drain apparatus <NUM> during priming and following treatment, the arterial patient line <NUM> may additionally or alternatively be attached to the drain apparatus <NUM> to prime and flush the arterial patient line <NUM>. For example, referring to <FIG>, before priming the hemodialysis system <NUM>, both the patient end <NUM> of the arterial patient line <NUM> and the patient end <NUM> of the venous patient line <NUM> can be attached to the drain apparatus <NUM> using the clip(s) <NUM> of the drain apparatus. A first end of the saline delivery line <NUM> can be attached to the saline bag <NUM> and a second end of the saline delivery line <NUM> can be attached to a port <NUM> on the arterial patient line <NUM>. To begin priming the system <NUM>, saline is introduced from the saline bag <NUM> through the saline delivery line <NUM> and through the port <NUM> on the arterial line <NUM>. Saline is first provided to the portion of the arterial patient line <NUM> between the patient end <NUM> of the arterial patient line <NUM> and the port <NUM> on the arterial patient line <NUM>.

Once the portion of the arterial patient line <NUM> between the patient end <NUM> of the arterial patient line <NUM> and the port <NUM> on the arterial patient line <NUM> is filled with saline, a clamp proximate the patient end <NUM> of the arterial patient line <NUM> is clamped. The blood pump <NUM> is then turned on to draw saline from the saline bag <NUM>, through saline delivery line <NUM> and the port <NUM> on the arterial patient line <NUM>, through a portion of the arterial patient line <NUM> between the port <NUM> on the arterial patient line <NUM> and the dialyzer <NUM>. The saline flows into the dialyzer <NUM> via the dialyzer inlet line <NUM> and exits the dialyzer <NUM> via the dialyzer outlet line <NUM>.

As the saline flows through the dialyzer outlet line <NUM> towards the air release device <NUM>, the saline passes through the venous pressure sensor <NUM>. Next, the saline flows through an entry port of the air release device <NUM> and fills the air release device <NUM>. Once the air release device <NUM> is filled with saline, a clamp on the venous patient line <NUM> is removed and saline flows through the venous patient line <NUM> towards the patient end <NUM> of the venous patient line <NUM>. Once the entire blood circuit <NUM> is filled with saline, any additional (e.g., excess) saline pumped through the blood component set <NUM> exits the patient end <NUM> of the venous patient line <NUM> and is captured by the chamber <NUM> of the drain apparatus <NUM>. Once all air is out of the patient lines <NUM>, <NUM> and the blood circuit <NUM> is filled with saline, a clamp is closed on the patient end <NUM> of the venous patient line <NUM>. Once clamped, the patient ends <NUM>, <NUM> of the patient lines <NUM>, <NUM> are removed from the drain apparatus <NUM>.

Similarly, in some implementations, both the arterial patient line <NUM> and the venous patient line <NUM> can be attached to the drain apparatus <NUM> to flush the patient lines <NUM>, <NUM> following dialysis. For example, referring to <FIG>, once a desired amount of the blood contained within the blood circuit <NUM> has been reinfused back to the patient <NUM>, the patient lines <NUM>, <NUM> are clamped, removed from the patient <NUM>, and both the patient end <NUM> of the arterial patient line <NUM> and the patient end <NUM> of the venous patient line <NUM> are attached to the drain apparatus <NUM> using the clip(s) <NUM>. A first end of the saline delivery line <NUM> can be attached to a saline bag <NUM> and a second end of the saline delivery line <NUM> can be attached to a port <NUM> on the arterial patient line <NUM>. Saline is introduced from the saline bag <NUM> through the port <NUM> on the arterial line <NUM> via the saline delivery line <NUM>.

Saline is first provided to the portion of the arterial patient line <NUM> between the patient end <NUM> of the arterial patient line <NUM> and the port <NUM> on the arterial patient line <NUM>. The saline exits the patient end <NUM> of the arterial patient line <NUM> into the chamber <NUM> of the drain apparatus. Saline is continuously provided until all remaining patient fluids in the portion of the arterial patient line <NUM> between the patient end <NUM> of the arterial patient line <NUM> and the port <NUM> on the arterial patient line <NUM> have been flushed into the drain apparatus <NUM>.

Once the portion of the arterial patient line <NUM> between the patient end <NUM> of the arterial patient line <NUM> and the port <NUM> on the arterial patient line <NUM> is flushed of patient fluids, a clamp proximate the patient end <NUM> of the arterial patient line <NUM> is clamped. The blood pump <NUM> is then turned on to draw saline from the saline bag <NUM> through the saline delivery line <NUM> and the port <NUM> on the arterial patient line <NUM> and circulate saline throughout all components of the blood circuit <NUM>. After circulating through the blood circuit <NUM>, the saline exits the patient end <NUM> of the venous patient line <NUM> and collects in the chamber <NUM> of the drain apparatus <NUM>. The drain apparatus outlet valve <NUM> is open and the drain apparatus pump <NUM> is turned on to draw the saline collected from the venous patient line <NUM> by the drain apparatus <NUM> to the drain line <NUM> via the outlet line <NUM>. Saline is continuously pumped through the blood circuit <NUM> until all remaining patient fluids have been flushed from the blood circuit <NUM> into the drain apparatus <NUM>. In some cases, for example, saline is pumped through the blood circuit <NUM> until the saline bag <NUM> is empty.

While the drain apparatus <NUM> has been described as including a clip <NUM> to attach the venous patient line <NUM> to the drain apparatus <NUM>, other mechanical attachment devices, such as clamps, ties, straps, hooks, latches, etc., can alternatively or additionally be used to attach the patient line(s) <NUM>, <NUM> to the drain apparatus. In some implementations, the drain apparatus <NUM> includes two or more mechanical attachment devices.

While the drain apparatus <NUM> has been described as including a coupler <NUM> to attach the vent <NUM> to the lid <NUM> of the drain apparatus <NUM>, in some examples the vent is coupled to the lid without a separate coupler. For example, as depicted in <FIG>, drain apparatus <NUM> includes a vent <NUM> with a clip portion <NUM> that is configured to flex and fill an opening <NUM> in the lid <NUM> and couple the vent <NUM> to the lid <NUM>. The clip portion <NUM> of the vent <NUM> is semi-rigid and compresses to fit into the opening <NUM> of the lid <NUM>. In addition, once positioned within the opening <NUM>, the clip portion <NUM> of the vent <NUM> expands to secure the vent <NUM> in place within the opening <NUM>. In order to remove the vent <NUM> from the lid <NUM>, a force is applied to the vent <NUM> and the diameter of the clip portion <NUM> of the vent <NUM> is compressed so that the clip portion <NUM> can slide out of the opening <NUM> of the lid <NUM>. Once removed from the lid <NUM>, the clip portion <NUM> of the vent <NUM> expands to its original, uncompressed diameter. In some examples, the vent <NUM> is replaced as part of periodic maintenance. In some implementations, a plurality of pores in hydrophobic filter <NUM> close in response to contact with water, and vent <NUM> is replaced following closure of the pores in the hydrophobic filter <NUM>.

In some examples, a leak detection sensor is positioned below the drain apparatus <NUM> (e.g., proximate the outlet port <NUM> of the drain apparatus) to detect malfunctions in the drain apparatus <NUM> resulting in fluid leaks from the drain apparatus <NUM>. The leak detection sensor can be communicably coupled to the drain apparatus inlet valve <NUM> and the drain apparatus inlet valve <NUM> can be automatically closed in response to the leak detection sensor detecting fluid leaking from the drain apparatus <NUM>.

While the arterial pressure sensor <NUM> has been described as being arranged upstream of the blood pump <NUM> to measure a pre-pump arterial pressure, it can alternatively be positioned downstream of the blood pump <NUM> to measure a post-pump arterial pressure, or an additional arterial pressure sensor can be positioned downstream of the blood pump <NUM> to measure a post-pump arterial pressure.

While the methods above involve circulating saline through the patient lines <NUM>, <NUM> and the blood circuit <NUM> to flush the patient lines <NUM>, <NUM> and blood circuit of any remaining patient fluids, alternatively air may be pumped through the blood circuit <NUM> and patient lines <NUM>, <NUM> to flush the patient lines <NUM>, <NUM> and blood circuit <NUM> of any remaining patient fluids. For example, the arterial patient line <NUM> can be disconnected from the saline delivery line <NUM>, and blood pump <NUM> can be used to draw air through the blood circuit <NUM> via the arterial patient line <NUM>.

While the methods above involve using valves <NUM> through <NUM> to control flow of disinfectant fluid to alternate the flow of disinfectant fluid between the first chamber halves <NUM>, <NUM> and second chamber halves <NUM>, <NUM>, alternatively all of the balancing device valves <NUM> through <NUM> can be opened during disinfection of the dialysate circuit <NUM>. For example, during disinfection, all of valve <NUM> through <NUM> can be open such that disinfectant fluid flowing out of mixing chambers <NUM>, <NUM> flows into all four chamber halves <NUM>, <NUM>, <NUM>, <NUM> simultaneously.

While the methods above involve disinfectant fluid flowing into the second chamber halves <NUM>, <NUM> of the balancing devices <NUM>, <NUM> from the air separation chamber <NUM> and disinfectant fluid flowing out of the second chamber halves <NUM>, <NUM> through valves <NUM>, <NUM>, alternatively valves <NUM> and <NUM> can remain closed during disinfection, such that as disinfectant fluid flows into first chamber half <NUM> of balancing devices <NUM>, disinfectant fluid is simultaneously forced out of the second chamber half <NUM> of balancing device <NUM> and into the second chamber half <NUM> of balancing device <NUM>. Similarly, in some implementations, as disinfectant fluid flows into first chamber half <NUM> of balancing devices <NUM>, disinfectant fluid is simultaneously forced out of the second chamber half <NUM> of balancing device <NUM> and into the second chamber half <NUM> of balancing device <NUM>.

Claim 1:
A drain apparatus (<NUM>) for a dialysis machine, the drain apparatus comprising:
a chamber (<NUM>) configured to receive an end of a fluid line extending from the dialysis machine;
a lid (<NUM>, <NUM>) configured to be coupled to the chamber to form a seal with the chamber;
a sensor (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to detect a fluid level in the chamber;
an inlet line (<NUM>) having a first end configured to be coupled to the chamber and a second end configured to be coupled to a fluid line of the dialysis machine;
an outlet line (<NUM>) having a first end configured to be coupled to the chamber and a second end configured to be coupled to a drain line of the dialysis machine; and
a valve (<NUM>) coupled to the outlet line and configured to control flow of fluid through the outlet line.