Blood treatment apparatus

Blood treatment device

Background of the invention

The invention relates to a blood treatment apparatus, and in particular to a blood treatment apparatus provided with a device for the online preparation of a treatment liquid.

Specifically, although not exclusively, the invention can be usefully applied in a dialysis machine equipped with a device for preparing a dialysis fluid from water and concentrates online.

As is well known, air bubbles in the dialysis liquid render the semipermeable dialyzer membrane ineffective. Therefore, a dialysis machine usually includes a device to remove the gas and minimize the gas in the dialysis fluid. For example, one type of gas removal system, as shown in US 3738382, includes a heater for heating water to a high temperature and a bubble removal chamber for removing gas from water heated to atmospheric pressure. . This system does not effectively degas the water and heating the water causes dissolved minerals to precipitate and clog the pipes inside the dialysis machine. A second type of gas removal system is shown in US 3528550. In this system water is fed to a degassing chamber that is maintained at a pressure below atmospheric pressure by a Venturi tube through which it flows The dialysis solution. Therefore, the pressure in the degassing chamber is directly related to the flow rate of the dialysis solution through the Venturi tube. The Venturi tube only applies a moderately negative pressure to the degassing tank and therefore does not effectively degas the water. In the degassing system shown in US 3528550, the pressure of the degassing chamber may vary with the flow rate of the dialysis solution which, in turn, may vary with the dialysis conditions, such as patient size, etc. Variations in the pressure of the degassing chamber can affect gas removal. During dialysis it is desirable to control the pressure of the dialysis solution in the dialyzer. However, changes in the dialysis solution flow rate through the dialyzer cause the dialysis solution pressure to vary.

US 4348280 provides a degassing system that operates independently of the dialysis solution flow rates and also provides means to control the dialysis solution pressure in the dialyzer when the dialysis solution flow rate changes. In the degassing system proposed by US 4348280, water is fed at normal body temperature to a degassing tank that is continuously subjected to a controllable high negative pressure. Pressure is provided by two pumps, one of them removing gas from the tank and extracting the other degassed water from the tank. Therefore, the pressure of the degassing tank is independent of the flow rate of the dialysis solution. The dialysis solution pressure and the flow rate in the dialyzer are controlled by a pair of flow restriction elements that are placed one upstream and the other downstream of the dialyzer. This allows precise control of the dialysis solution flow rate and the pressure inside the dialyzer.

US 4153554 discloses an apparatus for administering a dialysate solution to an artificial kidney. The apparatus prepares the solution by mixing water with a concentrated solution at a predefined ratio. Water enters a heater and then flows into a float tank that is filled with a controlled volume of water through a float controlled valve. Air bubbles are removed from the tank by means of a vacuum pump, which creates a partial vacuum in the float tank and passes air out of a ventilation hole. The water is then removed from the float tank by means of a supply pump and the pressure is increased again to a pressure of approximately +5 psig that is maintained by a pressure regulator disposed downstream of the supply pump. A deaerator removes the additional air from the water by passing the water over a vertical deflector near an upper air gap that is in communication with the upper part of the float tank by means of a conduit that has a restriction that is adapted to maintain the 5 psig pressure on the deaerator and therefore in the water when it comes out of the deaerator. Since the supply pump has to operate against a constant pressure of approximately 5 psig, it is possible to maintain a constant dialysate flow to an artificial kidney.

The hemodialysis apparatus of US 4828693 comprises means for removing the trapped air in the inlet water from the water stream before a metering pump. Air is removed in a deaeration loop using a deaerator that has a float valve and an air outlet. The inlet water is fed to a deaerator pressure regulator that has an outlet to the deaerator. The outlet of the deaerator is connected to a pump, and from there it returns to the pressure regulator completing the deaeration loop. The pump creates a negative pressure on the deaerator pressure regulator, drawing the inlet water into the deaerator, at which point the air trapped in the water escapes through the float valve and the air outlet at a lower negative pressure The deaeration pressure regulator controls the negative pressure at a selected value, for example -23 inches of mercury. The inlet water to the deaeration pressure regulator is generally controlled by a first pressure regulator at 12 psig. The outlet water of the deaeration pressure regulator is supplied to the metering pump. US 4828693 adds a second regulator, called a back pressure regulator, to receive the water from the deaeration pump and to control the pressure of that water to a value greater than 12 psig; for example, 15 psig. The back pressure regulator outlet then supplies water to the dialysate dosing pump. Therefore, the water pressure to the metering pump is independent of the inlet water pressure, since the deaerator loop serves as a constant volume water source to the pump and the pump is independent of the pressure and flow of the inlet water

US 4229299 discloses a dialysate dosing system provided with deaeration means for removing soluble gases from the heated water before passing it into the metering means. Water containing depolubilized gases is passed from a heater to a first tank with a vent hole. The partially deaerated water is removed from the first tank through a duct into a second tank with a vent hole. The duct has an adjustable flow restriction element that depressurizes the liquid to remove additional soluble gases therefrom. A pressure sensor is disposed downstream of the restriction element to allow any necessary adjustment of the flow restriction element in order to maintain a predetermined pressure level. A vacuum pump is arranged in the duct downstream of the pressure sensor. In order to improve the elimination of soluble gases, a recirculation duct joins the first tank with the second tank for the recirculation of a part of the water finally deaerated from the second tank to the first tank.

Document 5762782 describes a water treatment process for use in a dialysate preparation machine in which heated water is passed through a water pressure regulator past a manually operated valve. The pressure regulator supplies water to the dialysate preparation unit at a substantially constant pressure. The water then passes through a chamber loaded with a carbon filtration agent that removes organic material and dissolved gases from the water.

WO 00/57935 describes an apparatus for the preparation of peritoneal dialysis fluid in which preheated water passes through a series of components that remove dissolved gas from water. These components are a metering valve, a degassing restriction element, an expansion chamber, a degassing pump and a degassing chamber. In operation, water is recirculated from the degassing chamber by means of the metering valve through the degassing restriction element by means of the degassing pump. The decrease in pressure in the water due to the degassing restriction element causes the gas dissolved in the water to be forced out of the solution and begin to form bubbles in the water. The decrease in pressure due to the degassing restriction element is a function of the flow rate through it, which is kept constant by recirculation from the degassing chamber, at a flow rate set by the degassing pump.

The prior art also includes the AK 100/200 / 95® dialysis machines (produced by Gambro®) each comprising a blood treatment apparatus as in the preamble of claim 1.

Summary of the invention

A main object of the present invention is to effectively remove gas bubbles, especially air bubbles, from the entire circulatory system of a blood treatment apparatus to thereby increase the effectiveness of the treatment operation (eg, dialysate).

An advantage of the invention is to provide an economical and efficient degassing system for use in a blood treatment apparatus.

A further advantage of the invention is to provide a pump-type degassing system for use in a blood treatment apparatus in which the degassing is achieved effectively and effectively also when the degassing pump yields are reduced.

An additional advantage is to allow precise and reliable regulation of a desired gas concentration (neither too high nor too low) in the treatment liquid.

An additional advantage is to provide a device for the preparation of a treatment liquid provided with a pressure reducer disposed at the inlet of the hydraulic circuit in which there is no need to calibrate the pressure reducer when the device is installed at different altitudes.

Another advantage of the invention is that it provides a device for removing gases, which will allow a high separation rate to be achieved with a simple and compact type of construction.

An additional advantage of this invention is that it provides a pump-type degassing system for use in a blood treatment apparatus that is flexible because it can be adapted for use in various conditions and in which the relationship between degassing and other conditions. (altitude, dialysis fluid flow rate, dialysate fluid pressure, pump performance, etc.) will not change undesirably during operation.

A further advantage of the invention consists in the fact that the efficiency of the degassing pump can be maximized by appropriately selecting the degassing pressure set point.

These objects and advantages and many more, which will emerge best from the following description, are achieved by a blood treatment apparatus according to one or more of the appended claims.

Additional features and advantages of the present invention will best emerge from the following detailed description of at least one preferred embodiment of the invention, illustrated by way of non-limiting example in the accompanying figures of the drawings.

Brief description of the drawings

The description is given below in this document, with reference to the figures of the drawings, provided as a non-limiting example and in which:

Figure 1 is a schematic diagram of a blood treatment apparatus according to a first embodiment of the present invention;

Figure 2 is a schematic diagram of a blood treatment apparatus according to a second embodiment of the present invention.

Detailed description

With reference to Figure 1 of the drawings cited above, 1 indicates in its entirety a blood treatment apparatus, in particular a hemodialysis or heme (dia) filtration apparatus.

The blood treatment apparatus 1 comprises a blood treatment unit 2 (hemodialyzer or heme (dia) filter) having a fluid chamber 3, a blood chamber 4, and a semipermeable membrane 5 separating the fluid chamber 3 of chamber 4 of blood.

An extracorporeal blood circuit connects a vascular access 6 of the patient with the blood chamber 4. The extracorporeal blood circuit comprises an arterial conduit 7 for transporting the blood to be treated from the vascular access 6 to an entrance of the blood compartment 4, and a venous conduit 8 for returning the treated blood to the vascular access 6. The extracorporeal blood circuit may be any extracorporeal blood circuit used during a prior art blood treatment.

The blood treatment apparatus 1 comprises a treatment fluid supply conduit 9 comprising a water inlet connected to a water source 10, and a treatment fluid outlet connected to the fluid chamber 3 (hemodialysis treatment) and / or to the extracorporeal blood circuit (hemodiafiltration / hemofiltration treatment), in particular to arterial duct 7 and / or venous duct 8 (before and / or after dilution).

The blood treatment apparatus 1 comprises a preparation device 11 connected to the treatment fluid supply conduit 9 for preparing the treatment fluid from water and concentrates. In this specific case, the treatment fluid is a dialysis (dialysate) fluid that can be used to form a replacement fluid for heme (day) filtration treatments.

The blood treatment apparatus 1 further comprises a degassing conduit 12 having an inlet 13 for receiving fluid containing gas from the water inlet, and an outlet 14 for supplying degassed fluid to the treatment fluid outlet. In the present embodiment, the treatment fluid supply conduit 9 has a first junction point, which in this specific case coincides with the inlet 13 of the degassing conduit 12 and from which the degassing conduit 12 is branched, and a second junction point, which in this specific case coincides with the outlet 14 of the degassing duct 12 and into which the degassing duct 12 flows. In the present embodiment, the preparation device 11 is located between the water inlet and the gas inlet 13 containing gas; In another embodiment (not illustrated) the preparation device 11 is located between the outlet 14 of degassed fluid and the outlet of treatment fluid.

A degassing unit 15 is operatively connected to the degassing conduit 12. The degassing unit 15 comprises a gas separator 16 for separating the gas in the fluid containing gas flowing in the degassing conduit 12, a flow restriction element 17 to reduce the pressure of the fluid flowing in the conduit 12 degassing, a degassing pump 18 for circulating the fluid in the degassing conduit 12, a pressure sensor 19 for emitting a pressure signal indicative of the pressure in the degassing conduit 12, and a control unit 20 designed to control the speed of the degassing pump 18 based on the pressure signal emitted by the sensor 19 of pressure.

In the present embodiment, the gas separator 16 comprises a gas separation chamber. The signal used by the control unit 20 to control the degassing pump 18 is one that indicates the absolute pressure in the degassing conduit 12. In the present embodiment, the pressure sensor 19 is an absolute pressure sensor designed to emit an absolute pressure signal. The degassing pump 18 has an administration outlet connected to a fluid inlet of the gas separator 16. The degassing pump 18 is located in the degassing conduit 12 between the restriction element 17 and the gas separator 16. The degassing pump 18 is located in the degassing conduit 12 between the pressure sensor 19 and the gas separator 16. The pressure sensor 19 is located in the degassing conduit 12 between the restriction element 17 and the gas separator 16. The pressure sensor 19 is located in the degassing conduit 12 between the restriction element 17 and the degassing pump 18.

In this specific case, the degassing pump 18 is a positive displacement pump (for example, a gear pump).

The blood treatment apparatus 1 further comprises a discharge conduit 21 that connects the fluid chamber 3 with a drain. The gas separator 16 comprises a gas outlet connected through a vent duct 22 to the discharge duct 21. The ventilation duct 22 is provided with a shut-off valve 23 controlled by the control unit 20.

A one-way valve 24 is disposed in the treatment fluid supply line 9 between the first junction point (inlet 13) and the second junction point (outlet 14) to block the flow from inlet 13 to outlet 14 .

During operation, the flow rate of the dialysate in the degassing conduit 12 must be greater (for example, twice greater) than the flow rate in the treatment fluid supply conduit 9. The fluid (in this case, the dialysate) entering the inlet 13 contains air bubbles and dissolved air. In order to reduce the air in the fluid, the fluid is forced to pass through the deaeration restriction element 17. The speed of the pump 18 is controlled from the pressure, in particular the absolute pressure, in the degassing conduit 12. In this specific case, the pump speed is controlled in a closed loop based on the pressure signal emitted by the pressure sensor 19. In particular, the degassing pump 18 controls the pressure in the degassing conduit 12 at a constant absolute pressure (for example, 100 mm Hg) set to achieve a desired degassing effect, in particular a desired percentage of gas in the flow fluid. treatment. In this way, the desired amount of gas in the treatment fluid is always achieved under various conditions (decrease in the efficiency of the degassing pump 18, narrowing of the restriction element 17, difference in altitude, etc.).

The removed air is collected in the gas separator 16 (chamber) and periodically vented to the drain. In this case, the liquid level in the separation chamber is monitored by a level sensor (not shown). When the level sensor detects air in the chamber, the valve 23 opens to vent the accumulated air. The valve 23 closes when the level sensor detects liquid again.

Reference will now be made to Figure 2 which shows a second embodiment according to the invention. The numbering in figure 1 has also been maintained in figure 2 for similar elements.

The blood treatment apparatus (hemodialysis or heme (dia) filtration apparatus) of Figure 2 comprises a blood treatment unit 2 (hemodialyzer or heme (dia) filter) having a fluid chamber 3, a chamber 4 blood, and a semipermeable membrane 5 that separates the fluid chamber 3 from the blood chamber 4.

An extracorporeal blood circuit connects a vascular access of the patient (not shown) with the blood chamber 4. The extracorporeal blood circuit comprises an arterial duct 7 and a venous duct 8.

The blood treatment apparatus 1 comprises a treatment fluid supply conduit 9 having a water inlet connected to a water source 10, and a treatment fluid outlet connected to the fluid chamber 3 (hemodialysis treatment) and / or arterial duct 7 and / or venous duct 8 (hemodiafiltration / hemofiltration treatment before and / or after dilution).

The blood treatment apparatus 1 comprises a preparation device 11 connected to the treatment fluid supply conduit 9 for preparing the treatment fluid from water and concentrates. In this specific case, the treatment fluid is a dialysis (dialysate) fluid that can be used to form a replacement fluid for heme (day) filtration treatments. The treatment fluid preparation device 11 may comprise a central administration system connected to the blood treatment apparatus 1, or a device for preparing a fluid from water and concentrates.

The blood treatment apparatus 1 further comprises a degassing conduit 12 having an inlet 13 for receiving fluid containing gas from the water inlet, and an outlet 14 for supplying degassed fluid to the treatment fluid outlet. In this specific case, the treatment fluid supply conduit 12 has a first junction point, which in this specific case coincides with the inlet 13 of the degassing conduit 12 and from which the degassing conduit 12 is branched, and a second junction point, which in this specific case coincides with the outlet 14 of the degassing duct 12 and into which the degassing duct 12 flows. In this specific case, the preparation device 11 is located between the degassed fluid outlet 14 and the treatment fluid outlet.

A degassing unit 15 is operatively connected to the degassing conduit 12. The degassing unit 15 comprises a gas separator 16 for separating the gas in the fluid containing gas flowing in the degassing conduit 12, a flow restriction element 17 to reduce the pressure of the fluid flowing in the conduit 12 degassing, a degassing pump 18 for circulating the fluid in the degassing conduit 12, a pressure sensor 19 for emitting a pressure signal indicative of the pressure in the degassing conduit 12, and a control unit 20 designed to control the speed of the degassing pump 18 based on the pressure signal emitted by the sensor 19 of pressure.

In the present embodiment, the gas separator 16 comprises a gas separation chamber. The signal used by the control unit 20 to control the degassing pump 18 is a signal indicative of the absolute pressure in the degassing conduit 12. In this specific case, the pressure sensor 19 is an absolute pressure sensor designed to emit an absolute pressure signal. The degassing pump 18 has an administration outlet connected to a fluid inlet of the gas separator 16. The degassing pump 18 is located in the degassing conduit 12 between the restriction element 17 and the gas separator 16. The degassing pump 18 is located in the degassing conduit 12 between the pressure sensor 19 and the gas separator 16. The pressure sensor 19 is located in the degassing conduit 12 between the restriction element 17 and the gas separator 16. The pressure sensor 19 is located in the degassing conduit 12 between the restriction element 17 and the degassing pump 18. In the present embodiment, the degassing pump 18 is a positive displacement pump (for example, a gear pump).

The blood treatment apparatus 1 further comprises a discharge conduit 21 that connects the fluid chamber 3 with a drain. The gas separator 16 comprises a gas outlet connected through a drain conduit 22 to the drain. The ventilation duct 22 can be connected to the discharge duct 21. The ventilation duct 22 is provided with a shut-off valve 23 controlled by the control unit 20.

A one-way valve 24 is disposed in the treatment fluid supply line 9 between the first junction point (inlet 13) and the second junction point (outlet 14) to block the flow from inlet 13 to outlet 14 .

The apparatus of Figure 2 further comprises a pressure reducer 25 arranged immediately after the water inlet to control the pressure by restricting the flow of fluid. A normally closed inlet valve 26 is located downstream of the pressure reducer 25. The apparatus of Figure 2 comprises a first ultrafilter 27 designed to retain bacteria or endotoxins. The first ultrafilter has a first chamber (retention chamber) separated from a second chamber (permeate chamber) by means of a semipermeable membrane. A washing conduit 28 connects an outlet of the first chamber of the first ultrafilter with the drain. A hole 29 is disposed in the wash conduit 28 to limit the flow of the washed fluid through the first chamber and the wash conduit 28 and then into the drain. A check valve 30 prevents a return flow from the drain from contaminating the first ultrafilter 27.

A heater 31 is disposed in the degassing conduit 12 upstream of the restriction element 17 to heat the inlet fluid. A temperature sensor 32 measures the temperature of the fluid in the degassing conduit 12 (downstream of the heater 31). The control unit 20 controls the heater 31 to ensure that the temperature measured by the sensor 32 is within a desired range. A flow switch 33 is disposed in the degassing conduit 12. The control unit 20 recognizes an alarm situation (and disconnects the power of the heater 31, for example) when the flow rate through the flow switch 33 is less than a predetermined value. In another embodiment (not shown), the heater 31 is located downstream of the restriction element 17, for example, between the restriction element 17 and the degassing pump 18, or between the restriction element 17 and the pressure sensor 19 .

A bypass valve 34 of the restriction element is disposed in a bypass conduit connected to the degassing conduit 12, to bypass the restriction element 17. The bypass valve 34 of the restriction element, which is normally closed, opens during a heat disinfection procedure (which serves to disinfect the hydraulic circuit of the blood treatment apparatus) and closes during a blood treatment procedure. When the bypass valve 34 of the restriction element is opened during a heat disinfection process, the degassing restriction element 17 is derived in order to prevent the heated liquid (water) from boiling.

A pressure regulator 35 is disposed in the treatment fluid supply conduit 9 between the degassing conduit 12 and a supply pump 36 which circulates a fluid in the treatment fluid supply conduit 9. The pressure regulator 35 is disposed downstream of the degassing conduit 12. The pressure regulator 35 is set to maintain a desired pressure in the sources 37a and 37b of concentrate. When the sources of concentrate comprise cartridges of dry concentrates, moderate overpressure within the cartridges may be desirable. The pressure regulator 35 prevents a pressure that is too low to produce gas bubbles upstream of the supply pump 36. In addition, the pressure regulator 35 prevents or reduces pressure peaks from the gas separator 16 (gas separation chamber or bubble trap) during the evacuation of the gas described above.

The treatment fluid preparation device (dialysate) comprises at least two injection ducts each operatively associated with a concentrate source 37a and 37b (liquid or solid concentrates), a dosing pump 38a and 38b, and a sensor 39a and 39b of conductivity that controls a respective dosing pump at a set conductivity value. The injection lines are supplied with a solvent (for example, water) from a line that branches off the treatment fluid supply line 9.

The apparatus of Figure 2 comprises a second ultrafilter 40 designed to retain bacteria or endotoxins. The second ultrafilter 40 has a first chamber (retention chamber) separated from a second chamber (permeate chamber) by means of a semipermeable membrane. A wash conduit 41 connects an outlet of the first chamber of the second ultrafilter 40 with the discharge conduit 21. The wash conduit 41 is provided with a wash valve 42 that opens periodically (or under predetermined conditions) to tangentially wash the second ultrafilter 40.

A first bypass line 43 is disposed upstream of the second ultrafilter 40 to connect the supply line 9 with the discharge line 21. The first bypass line 43 is provided with a first valve 44

5 bypass A second bypass conduit 45 is disposed downstream of the second ultrafilter 40 to connect the supply conduit 9 with the discharge conduit 21. The second bypass conduit 45 is provided with a second bypass valve 46. A shut-off valve 47 is disposed in the discharge conduit 21 before the second bypass conduit 45. A discharge pump 48 is disposed downstream of the washing line 41. The discharge pump 48 is disposed downstream of the first and second bypass lines 43 and 45. The discharge pump 48 circulates the fluid to the drain. A fluid balancing system controls the discharge pump 48 (and the supply pump 36) to regulate the weight loss of a patient undergoing blood treatment. In this specific case, the fluid balance system comprises an upstream flowmeter 49 disposed before the blood treatment unit 2 in the supply conduit 9, and a downstream flowmeter 50 disposed after the blood treatment unit 2 in the discharge duct 21.

fifteen The control unit 20 is designed to control the degassing pump 18 (during treatment) at a flow rate that is greater than that of the treatment fluid supply pump 36. During the treatment, the valve 34 is closed and the fluid (water) is passed through the degassing restriction element 17. The degassing system of the apparatus of Figure 2 works as described above to reduce the gas in the fluid.

The control unit 20 is designed to control the degassing pump 18 at a predetermined degassing pressure set point.

The degassing pressure can be set as low as possible in order to maximize the degassing performance, that is, the removal of oxygen. However, there are some limitations as to how low the degassing pressure can be set. For example, a degassing pressure that is too low can result in cavitation in the pump resulting in increased wear and / or loss of pump efficiency.

25 The degassing set point selection can be a balance between degassing performance and other requirements such as, for example, the duration of the pump, the cost and the energy consumption.

In a further embodiment (not shown), A blood treatment apparatus differs from the apparatus of Figure 1 (or Figure 2) only in that the pressure signal indicating the absolute pressure in the degassing conduit 12 can be supplied by processing two pressure signals emitted by a first sensor relative pressure disposed in the degassing conduit 12 (in the same location as the absolute pressure sensor 19) and a second pressure sensor indicating the atmospheric pressure. A calculation unit can calculate an absolute pressure value from said two pressure signals, for example, as a difference between the pressure values ​​indicated by the two pressure signals. The control unit 20 may include the calculation unit.

In a further embodiment (not shown), a blood treatment apparatus differs from the apparatus of Figure 1 (or

35 Figure 2) only in that the degassing conduit forms a section (initial, intermediate or final section) of the treatment fluid supply conduit without forming a loop between two junction points thereof. In this embodiment, the degassing conduit and the treatment fluid supply conduit form a continuous fluid conduit, whereby the flow rate of the degassing conduit is equal to the flow rate of the treatment fluid supply conduit and the supply pump of the treatment fluid supply conduit can act as a degassing pump of the degassing conduit.

Legends:

1 Blood treatment device

two Blood treatment unit

3 Fluid chamber

Four. Five 4 Chamber of blood

5 Semipermeable membrane

6 Vascular access of the patient

7 Arterial duct

8 Venous duct

9 Treatment fluid supply conduit

10 Water source

<dl><dt>11 </dt><dd>Treatment fluid preparation device </dd></dl>

<dl><dt>12 </dt><dd>Degassing duct </dd></dl>

<dl><dt>13 </dt><dd>Degassing duct inlet </dd></dl>

<dl><dt>14 </dt><dd>Degassing duct outlet </dd></dl>

<dl><dt>15 </dt><dd>Degassing unit </dd></dl>

<dl><dt>16</dt><dd> Gas separator </dd></dl>

<dl><dt>17 </dt><dd>Flow Restriction Element </dd></dl>

<dl><dt>18 </dt><dd>Degassing pump </dd></dl>

<dl><dt>19 </dt><dd>Pressure sensor </dd></dl>

<dl><dt>20 </dt><dd>Control unit </dd></dl>

<dl><dt>21 </dt><dd>Discharge duct </dd></dl>

<dl><dt>22 </dt><dd>Ventilation duct </dd></dl>

<dl><dt>23 </dt><dd>Closing valve </dd></dl>

<dl><dt>24 </dt><dd>One-way valve </dd></dl>

<dl><dt>25 </dt><dd>Pressure reducer </dd></dl>

<dl><dt>26</dt><dd> Inlet valve </dd></dl>

<dl><dt>27 </dt><dd>First ultrafilter </dd></dl>

<dl><dt>28 </dt><dd>Washing duct </dd></dl>

<dl><dt>29 </dt><dd>Orifice </dd></dl>

<dl><dt>30 </dt><dd>Retention valve </dd></dl>

<dl><dt>31</dt><dd> Heater </dd></dl>

<dl><dt>32 </dt><dd>Temperature sensor </dd></dl>

<dl><dt>33 </dt><dd>Flow switch </dd></dl>

<dl><dt>34 </dt><dd>Restriction Element Bypass Valve </dd></dl>

<dl><dt>35 </dt><dd>Pressure regulator </dd></dl>

<dl><dt>36 </dt><dd>Supply pump </dd></dl>

<dl><dt>37 </dt><dd>Sources of concentrate (37a, 37b) </dd></dl>

<dl><dt>38 </dt><dd>Dosing pumps (38a, 38b) </dd></dl>

<dl><dt>39 </dt><dd>Conductivity sensors (39a, 39b) </dd></dl>

<dl><dt>40 </dt><dd>Second ultrafilter </dd></dl>

<dl><dt>41 </dt><dd>Washing duct </dd></dl>

<dl><dt>42 </dt><dd>Wash valve </dd></dl>

<dl><dt>43 </dt><dd>First bypass duct </dd></dl>

<dl><dt>44 </dt><dd>First bypass valve </dd></dl>

<dl><dt>45 </dt><dd>Second bypass duct </dd></dl>

<dl><dt>46 </dt><dd>Second bypass valve </dd></dl>

<dl><dt>47 </dt><dd>Closing valve </dd></dl>

<dl><dt>48 </dt><dd>Discharge pump </dd></dl>

<dl><dt>49 </dt><dd>Upstream flowmeter </dd></dl>

<dl><dt>50 </dt><dd>Downstream flowmeter</dd></dl>