In-line sensors for dialysis applications

Abstract

A fluid preparation apparatus for a renal failure treatment is disclosed. In an example, the fluid preparation apparatus includes an inlet configured to receive water from a water source and a fluid line fluidly connected to the inlet. The apparatus also includes a pump fluidly connected to the fluid line. The pump is configured to pump concentrate from a concentrate container to mix with the water to form a fluid mixture. The apparatus further includes a sensor configured to measure a composition characteristic of the fluid mixture. Additionally, the apparatus includes a controller operably coupled to the pump, the sensor, and a valve. The controller is configured to receive a composition characteristic value from the sensor, and cause the valve to route the fluid mixture for the renal failure treatment when the composition characteristic value indicates that the fluid mixture is suitable for the renal failure treatment.

What is claimed is: 
     
         1 . A fluid preparation apparatus for a renal failure treatment comprising:
 an inlet configured to receive water from a water source;   a fluid line fluidly connected to the inlet;   a concentrate pump fluidly connected to the fluid line at a mixing point, the concentrate pump configured to pump concentrate from a concentrate container to mix with the water beginning at the mixing point to form a fluid mixture;   a sensor located downstream from the mixing point and configured to measure a composition characteristic of the fluid mixture;   a valve located downstream from the sensor; and   at least one controller operably coupled to the concentrate pump, the valve, and the sensor, the at least one controller configured to
 receive at least one composition characteristic value from the sensor, and 
 cause the valve to route the fluid mixture for the renal failure treatment when the at least one composition characteristic value indicates that the fluid mixture is suitable for the renal failure treatment. 
   
     
     
         2 . The fluid preparation apparatus of  claim 1 , wherein the sensor comprises an ion-selective sensor suitable for sensing two or more of an ion selected from the group consisting of ammonium, sodium, calcium, magnesium, potassium, carbonate, bicarbonate, hydrogen or hydronium, hydroxyl, chloramine, and chloride. 
     
     
         3 . The fluid preparation apparatus of  claim 1 , wherein the composition characteristic is at least one of a conductivity, a pH, a temperature, a total dissolved solids, a calcium level, a magnesium level, a total hardness, or a carbonate alkalinity. 
     
     
         4 . The fluid preparation apparatus of  claim 1 , wherein the sensor is an amperometric sensor suitable for sensing chlorine and chloramines. 
     
     
         5 . The fluid preparation apparatus according to  claim 1 , wherein the water comprises fresh water or a spent dialysis solution. 
     
     
         6 . The fluid preparation apparatus of  claim 1 , further comprising a mixing chamber located at the mixing point, the mixing chamber configured to enable the water to mix with the concentrate from the concentrate container. 
     
     
         7 . The fluid preparation apparatus of  claim 1 , wherein the fluid line is a to-patient fluid line and the sensor is a first sensor, the apparatus further comprising:
 a patient outlet line positioned to receive used dialysate from a patient; and   a second sensor provided in the patient outlet line to measure a composition characteristic of the used dialysate.   
     
     
         8 . The fluid preparation apparatus of  claim 7 , wherein the at least one controller is operably connected to the second sensor and configured to (i) route the used dialysate to a drain line when a value of the composition characteristic of the used dialysate indicates that the used dialysate is not reusable, and (ii) route the used dialysate to the fluid line before the mixing point for reuse when at least one composition characteristic value of the used dialysate indicates that the used dialysate is reusable. 
     
     
         9 . The fluid preparation apparatus of  claim 7 , wherein the composition characteristic of the used dialysate is at least one of a conductivity, a pH, a temperature, a total dissolved solids, a calcium level, a magnesium level, a total hardness, or a carbonate alkalinity. 
     
     
         10 . The fluid preparation apparatus of  claim 1 , wherein the at least one controller is further configured to:
 determine whether a pumping speed of the concentrate pump is to be adjusted based on the at least one composition characteristic value;   adjust the pumping speed of the concentrate pump based on the at least one composition characteristic value, so that the fluid mixture forms a solution suitable for the renal failure treatment; and   when the at least one composition characteristic value does not indicate that the fluid mixture is suitable for the renal failure treatment, (i) adjust the pumping speed of the concentrate pump to produce a new fluid mixture, and (ii) cause the valve to route the fluid mixture to a point located before the mixing point for generating the new fluid mixture.   
     
     
         11 . A system for preparing dialysis fluid, the system comprising:
 a purification cartridge comprising a purification medium for water;   a heater for heating the water received from the purification cartridge;   a pump for pumping and metering a concentrate;   a mixing chamber configured for receiving the concentrate from the pump and for mixing the concentrate with the water at a mixing point to form a fresh dialysis solution;   a filter for filtering the fresh dialysis solution; and   a sensor located downstream from the mixing point and configured to measure a composition characteristic of the fresh dialysis solution;   a valve located downstream from the sensor; and   at least one controller operably coupled to the pump, the valve, and the sensor, the at least one controller configured to
 receive at least one composition characteristic value from the sensor, and 
 cause the valve to route the fresh dialysis solution for the renal failure treatment when the at least one composition characteristic value indicates that the fresh dialysis solution is suitable for the renal failure treatment. 
   
     
     
         12 . The system of  claim 11 , further comprising an ultrafilter for removing bacteria and microorganisms from the water or from the fresh dialysis solution. 
     
     
         13 . The system of  claim 11 , further comprising a reverse osmosis filter for cleaning the water or the fresh dialysis solution. 
     
     
         14 . The system of  claim 11 , further comprising an ultraviolet light source for irradiating the water or the fresh dialysis solution, the ultraviolet light source placed upstream of the filter. 
     
     
         15 . The system of  claim 11 , further comprising an air trap for removing air from the fresh dialysis solution. 
     
     
         16 . The system of  claim 11 , wherein the water comprises fresh water or a spent dialysis solution. 
     
     
         17 . The system of  claim 11 , wherein the sensor is a first sensor, the system further comprising:
 a patient outlet line positioned to receive used dialysate from a patient; and   a second sensor provided in the patient outlet line to measure a composition characteristic of the used dialysate.   
     
     
         18 . The system of  claim 17 , wherein the at least one controller is operably connected to the second sensor and configured to (i) route the used dialysate to a drain line when a value of the composition characteristic of the used dialysate indicates that the used dialysate is not reusable, and (ii) route the used dialysate to the fluid line before the mixing point for reuse when at least one composition characteristic value of the used dialysate indicates that the used dialysate is reusable. 
     
     
         19 . The system of  claim 17 , wherein the composition characteristic of the used dialysate is at least one of a conductivity, a pH, a temperature, a total dissolved solids, a calcium level, a magnesium level, a total hardness, or a carbonate alkalinity. 
     
     
         20 . The system of  claim 11 , wherein the at least one controller is further configured to:
 determine whether a pumping speed of the pump is to be adjusted based on the at least one composition characteristic value;   adjust the pumping speed of the pump based on the at least one composition characteristic value, so that the fluid mixture forms a solution suitable for the renal failure treatment; and   when the at least one composition characteristic value does not indicate that the fluid mixture is suitable for the renal failure treatment, (i) adjust the pumping speed of the pump to produce a new fluid mixture, and (ii) cause the valve to route the fluid mixture to a point located before the mixing point for generating the new fluid mixture.