Valve assembly for liquid dispensing unit and liquid dispensing unit for water purification system

Abstract

The present application relates to a valve assembly (10) for a liquid dispensing unit and a liquid dispensing unit for a water purification system, and to such a water purification system.

Description

Technical Field

[0001] The present invention relates to a valve assembly for a liquid dispensing unit and a liquid dispensing unit for a water purification system, and such a water purification system. Background Art

[0002] Most existing water purification and distribution systems for ultrapure water use solenoid valves to control the opening and closing of the dispensing unit. However, the solenoid valve only has an on-off setting. Therefore, some systems couple the solenoid valve with a motorized valve to allow the user to precisely control the dispensing flow rate (from drop-by-drop (or "drop-by-drop") dispensing to high flow rates). Both the solenoid valve and the motorized valve can be integrated together in the dispensing unit, or the motorized valve can be placed in a remote main system and only the solenoid valve placed in the dispensing unit.

[0003] Prior art water purification and distribution systems for ultrapure water are described, for example, in US 5,925,240 A, WO 2010 / 043899 A1 and US 11,035,484 B2.

[0004] These existing systems have several drawbacks:

[0005] (i) A PCB (Printed Circuit Board) with electronic components must be integrated into the distribution unit, where power is transmitted from the remote main system to the distribution or distribution unit;

[0006] (ii) solenoid valves and electric valves together are bulky components, which limits the integration and design options of the dispensing unit in order to maintain ergonomic operation;

[0007] (iii) energizing the actuating coil of the solenoid valve for a long period of time may cause heating, which may impair the quality of the purified water dispensed from the dispensing or dispensing unit;

[0008] (iv) In systems with more than one dispensing or dispense unit, an electric valve coupled to several solenoid valves allows only one flow rate setting at a time and it is not possible to set different flow rates for different dispensing or dispense units.

[0009] Fluid distribution systems often use valve assemblies with a pair of ceramic disks having openings, windows, or recesses that are opened and closed by relative rotation of the disks. One disk remains stationary within a housing, while the other disk is movable and driven to rotate to align or separate the disk openings, windows, or recesses, thereby allowing or preventing fluid flow through the valve assembly.

[0010] Utilize good surface properties, the discs adhere together, and when the openings, windows or recesses of the discs do not face each other (or overlap), a seal is achieved. This concept uses ceramic materials because they can have excellent surface properties after modification, which means that when the discs are in the closed position, fluid cannot flow between the discs. In addition, ceramic materials are extremely hard and wear-resistant so that ceramic valves can be used millions of times without damaging the seal. Therefore, this technology is commonly used in faucets sold on the consumer market. However, existing designs do not allow for precise distribution of flow rates as low as drop by drop, and / or can only be operated by applying significant force or momentum (which requires the actuator to be grasped by the user's whole hand).

[0011] The present invention aims to provide a valve assembly for a liquid dispensing unit and a liquid dispensing unit for a water purification system that solves at least one of the problems associated with existing solutions.

[0012] The present invention is particularly intended to provide a valve assembly for a liquid dispensing unit and a liquid dispensing unit for a water purification system (preferably a pure water or ultrapure water purification and dispensing system), which can control the opening and closing of dispensing, as well as the flow rate of dispensing as low as drop-by-drop (or "drop-by-drop") dispensing, while reducing size, cost and environmental impact by reducing the number of components and avoiding electronic devices, further allowing easy ergonomic operation and / or easy and robust assembly. Summary of the Invention

[0013] In order to solve the indicated problem, the present invention provides a valve assembly for a liquid dispensing unit as defined by claim 1 and a liquid dispensing unit for a water purification system as defined by claim 15. Preferred embodiments of the valve assembly and the liquid dispensing unit are defined in the dependent claims.

[0014] The present invention particularly provides a valve assembly for a liquid dispensing unit, comprising a pair of first and second disks to be rotated relative to each other, wherein mutually facing first and second sealing contact surfaces are arranged to be at least partially in sliding contact with each other, wherein the first disk has at least one window, and wherein the second disk has a solid portion and an opening portion, wherein the solid portion is arranged to completely cover and thereby close the at least one window of the first disk in a fully closed rotational position, and the opening portion is arranged to at least partially expose the at least one window of the first disk in a fully open rotational position.

[0015] Preferably, the solid portion of the second disc arranged to completely cover to close at least one window of the first disc in the fully closed rotational position is formed so as to include a portion of the second sealing contact surface which overlaps with the first sealing contact surface of the first disc surrounding the edge of the window via a sealing area having a width of 1.5 mm, preferably at least 2.0 mm.

[0016] Preferably, the first and second sealing contact surfaces of the pair of first and second disks arranged at least partially in sliding contact with each other have a surface roughness Ra of at most 0.60 μm and / or a surface flatness of at most 0.80 μm, and are preferably polished or ground.

[0017] Preferably, the mutually facing first and second sealing contact surfaces of the pair of first and second discs are arranged so that between the fully closed rotational position and the fully open rotational position, 50% to 80%, preferably 55% to 75%, and most preferably 60% to 70% of the first and second sealing contact surfaces are in sliding contact with each other.

[0018] Preferably, the second disc is in free floating contact with the first disc or is biased towards the first disc by a biasing member.

[0019] Preferably, the at least one window of the first disc has a notch / indentation recessed into the material of the first disc from a plane defined by the first sealing contact surface of the first disc at one / the edge of the at least one window at the side where exposure of the at least one window begins when the second disc moves from the fully closed rotational position in the direction towards the fully open rotational position.

[0020] Preferably, the notch / indentation has a sharp end that gradually widens and / or deepens towards the at least one window.

[0021] Preferably, at least one window has an inclination or slope at a side wall adjacent to one / the side where exposure of the at least one window begins when the second disc moves from the fully closed rotational position in one / the direction toward the fully open rotational position, so that the free opening width of the at least one window in the thickness direction of the first disc gradually narrows with the distance from the plane of the first sealing contact surface.

[0022] Preferably, the valve assembly is sized to provide a flow rate through the at least one window from dropwise, preferably 20 mL / min, up to 2 L / min, within the range of rotational angles of relative movement between the fully closed rotational position and the fully open rotational position.

[0023] Preferably, the rotation angle between the fully closed rotation position and the fully open rotation position ranges from 50° to 70°, preferably from 55° to 65°, and most preferably about 60°.

[0024] Preferably, the first disc is provided with a positioning recess for preventing rotation and defining an installation position in the receiving portion of the liquid dispensing unit, and the positioning recess is formed and / or arranged asymmetrically with respect to the circumference of the first disc.

[0025] Preferably, the second disc is provided with one or more driver recesses and / or protrusions on a side opposite to the second sealing contact surface for engagement with a rotary actuator of the liquid dispensing unit.

[0026] Preferably, the first disc has a circular outer periphery and the second disc has a non-circular outer periphery, wherein the opening portion is arranged to at least partially expose the at least one window of the first disc, radially recessed from the outer periphery.

[0027] Preferably, the first disk and / or the second disk are made of a ceramic material, preferably alumina ceramic.

[0028] The present invention also provides, in particular, a liquid dispensing unit for a water purification system, comprising a supply pipe for purified water, an outlet for the purified water, and a valve assembly according to the present invention, which is arranged in a receiving portion of a housing so that the valve assembly can control the amount or rate of flow of purified water from the supply pipe to the outlet.

[0029] Preferably, the first disc of the valve assembly is rotationally fixed in position within the housing such that the at least one window communicates with the outlet, and the second disc is mounted in the housing so as to be in free-floating contact with the first disc and such that the first and second sealing contact surfaces are pressed against each other by water pressure from the supply conduit acting on the second disc.

[0030] Preferably, the second disc of the valve assembly is engaged by a manually operable rotary actuator for rotationally driving the second disc relative to the first disc between a fully closed rotational position and a fully open rotational position.

[0031] Furthermore, the present invention provides a water purification system comprising such a liquid dispensing unit as defined herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A perspective schematic diagram of an exemplary first disc of a valve assembly is shown.

[0033] Figure 2 A perspective schematic diagram illustrating an exemplary second disc of a valve assembly is shown.

[0034] Figure 3 A schematic top view of a valve assembly is shown, wherein Figure 1 and Figure 2 The first disc and the second disc are superimposed on each other.

[0035] Figure 4 A schematic partial cross-sectional side view of an exemplary dispensing unit provided with a valve assembly is shown.

[0036] Figure 5Schematic cross-sectional top views of an exemplary dispensing unit are shown with the valve assembly in a closed position (left view) and an open position (right view). DETAILED DESCRIPTION

[0037] The valve assembly of the present invention is a mechanical valve comprising a single pair of discs (preferably made of a ceramic material) that can be integrated into a dispensing unit of a water purification system to replace both electric and solenoid valves. The single pair of discs can be used to control the opening and closing of flow through the valve assembly, as well as dispensing flow rates ranging from drop-by-drop dispensing to high flow rates (i.e., from 20 mL / min to 2 L / min).

[0038] The mechanical valve assembly provides one or more of the following advantages over existing products due to its reduced size and complexity:

[0039] (i) The ability to have several dispensing units dispensing simultaneously at different flow rates in a single water purification system;

[0040] (ii) by removing the solenoid valve (and electric valve, if provided) and the PCB from the dispensing unit and / or the delivery unit, the size of the dispensing unit can be reduced, which provides for improved ergonomic handling of the dispensing unit;

[0041] (iii) the number and complexity of components of the distribution unit and / or dispenser unit can be reduced. In particular, the avoidance of electronics means that it is not necessary to provide power or control circuits to the distribution unit from a main system with a purification stage, and the connection between the main system and the distribution unit can be reduced to a double or single conduit, instead of two conduits and an electronic cable, all of which must be integrated in an outer casing or connected together by suitable means (e.g. cable ties);

[0042] (iv) From an environmental point of view, the simplicity of construction and the absence of electronic components are also advantageous, reducing the carbon footprint of the dispensing and / or delivery unit and improving its recyclability;

[0043] (v) the possibility of omitting the electronic part from the distribution unit and / or the dispensing unit further simplifies maintenance and repair of the unit if necessary, since no electronic connections need to be made;

[0044] (vi) from a manufacturing perspective, the valve assembly and liquid dispensing unit provided with the valve assembly provide simplified and more robust (ie, error-free) assembly; and

[0045] (vii) Finally, the valve assembly and the liquid dispensing unit equipped with it enhance design freedom: placing electronics close to hydraulic components in a small, enclosed space is a risk. This constrains the design of liquid dispensing or dispenser units, forcing inflow from the lower portion of the gun in most existing products. The absence of electronics, made possible by the use of a mechanical valve assembly, simplifies the constraints on the dispensing or dispenser unit's design and, from this perspective, reduces risk.

[0046] Referring now to the attached exemplary schematic diagram ( Figures 1 to 5 ) The present invention is described in detail based on preferred exemplary embodiments.

[0047] The valve assembly for a liquid dispensing unit and the liquid dispensing unit for a water purification system of the present invention will now be described with reference to exemplary embodiments.

[0048] Valve assembly 10 for liquid dispensing unit 1 (see Figure 4 ) includes a pair of first and second discs 11 and 12 to be rotated relative to each other, wherein first and second sealing contact surfaces 11a and 12a facing each other are arranged to be in at least partially sliding contact with each other.

[0049] The first disc 11 has at least one window 13a, 13b (two in the embodiment, at positions opposite to each other through the center of the disc). The second disc 12 has solid parts 14a, 14b and openings 15a, 15b, the solid parts 14a, 14b being arranged to be in the fully closed rotation position ( Figure 3 13a, 13b of the first disc 11, and the opening portions 15a, 15b are arranged to at least partially expose the at least one window 13a, 13b of the first disc 11 during a progressive relative rotation until it is positioned in a fully open rotational position. Here, too, the two solid portions 14a, 14b and the two opening portions 15a, 15b are provided in an embodiment to complement the two windows 13a, 13b of the first disc.

[0050] Although two of the windows and the corresponding open portion and solid portion are arranged in a rotationally symmetrical manner, the number may be one each or more than two distributed around the circumference.

[0051] As described subsequently, the windows 13a, 13b extend through the thickness of the first disc in the axial direction and serve as flow paths for fluid through the valve assembly in the axial direction.

[0052] The solid portion(s) 14a, 14b of the second disc 12, which is arranged to completely cover and thus close the window(s) 13a, 13b of the first disc 11 in the fully closed rotational position, is formed so as to include a portion of the second sealing contact surface 12a which overlaps with the first sealing contact surface 11a of the first disc 11 in a closed sealing area 16a, 16b surrounding the edges 13c, 13d of the window(s) 13a, 13b, respectively. The sealing areas 16a, 16b have a width of at least 1.5 mm, preferably at least 2.0 mm, to ensure sealing in the fully closed position (see Figure 3 ), the width being measured perpendicular to the edge, or more precisely, perpendicular to the tangent to the edge in the plane of the first sealing contact surface 11a and the second sealing contact surface 12a. The sealing of the housing of the dispensing unit in which the valve assembly is integrated is performed on the surface opposite to the first sealing contact surface 11a of the first disc 11 (if Figure 4 In the example of a lower disk, it can be implemented on the lower surface of the first disk and therefore requires a certain circular area without openings on the outside of the surface. These two requirements, combined with the need to maximize the opening area of ​​the window to set the desired maximum flow rate, determine the size, shape and characteristics of the two disks.

[0053] First disc 11 and / or second disc 12 are preferably made of a ceramic material. When the valve assembly is to be integrated into a dispensing or distribution unit for ultrapure water, the type of ceramic material used should be selected to avoid any contamination of the ultrapure water. Alumina ceramic is a suitable and preferred material. However, depending on the situation and whether the required sealing performance of the sealing contact surface of the disc can be achieved, another material including a metal or alloy, or a different substrate with a suitable coating (including a ceramic coating) is possible.

[0054] The first disc 11 in the embodiment has a circular outer periphery, and the second disc 12 has a non-circular outer periphery, wherein the opening portions 15a, 15b are arranged to at least partially expose at least one window 13a, 13b of the first disc 11, radially recessed from the outer periphery (see Figure 2 However, the disc may have a peripheral shape other than circular. If the peripheral shape is "not circular", it may be convenient to retain at least one disc (i.e., the stationary disc) in the housing of the dispensing unit to prevent rotation by engagement with a correspondingly shaped recess or protrusion.

[0055] The first plate 11 is provided with positioning notches 17a, 17b at its periphery for positioning in the installation state. Figure 4 The dispensing unit 1 shown in FIG is prevented from rotating in the housing 2 and serves to define a unique installation position in the housing 2. The positioning recesses 17a, 17b are formed and / or arranged asymmetrically about the circumference of the first disc 11 in order to define a unique installation position.

[0056] The second disc 12 is provided with one or more driver recesses 18a, 18b and / or protrusions (not shown) on the side opposite to the second sealing contact surface 12a in the axial direction for engaging with the rotary actuator 3 of the liquid dispensing unit 1. In an embodiment, the recesses 18a, 18b are shallow recesses or grooves with a closed bottom that do not extend through the thickness of the second disc in the axial direction. The rotary actuator 3 is provided with matching protrusions 3a, 3b (see Figure 4 ) for engaging with the recesses 18a, 18b. The shape or profile of the recesses 18a, 18b and the matching protrusions 3a, 3b are asymmetrical so as to define a unique mounting orientation, or more precisely, a defined rotational position of the actuator 3 in which engagement is possible.

[0057] The sealing performance of disks 11, 12 depends primarily on the percentage of disk sealing contact surfaces 11a, 12a that are effectively in contact at the microscopic level. Therefore, the disk sealing contact surfaces are sized to achieve a predetermined percentage of the surface area in contact between the two disks. A percentage that is too low will compromise the seal, while a percentage that is too high will cause excessive operating effort. In the absence of external forces exerted on the disks during integration into a dispensing unit, as described below, this percentage of disk surface in contact, along with the water pressure and the friction of the seal on the actuator, is the only parameter that influences operating effort.

[0058] The first and second sealing contact surfaces 11a, 12a of the pair of first and second disks 11, 12, which are arranged at least partially in sliding contact with each other, have a surface quality or surface roughness Ra of at most 0.60 μm, more preferably at most 0.50 μm, most preferably at most 0.40 μm, and / or a flatness of at most 0.80 μm, preferably at most 0.70 μm, most preferably at most 0.60 μm, to produce a liquid-tight seal when in contact. Preferably, the first and second sealing contact surfaces 11a, 12a of the pair of first and second disks 11, 12 are polished or ground.

[0059] The mutually facing first and second sealing contact surfaces 11a, 12a of the pair of first and second discs 11, 12 are arranged so that between the fully closed rotational position and the fully open rotational position, 50% to 80%, preferably 55% to 75% and most preferably 60% to 70% of the first and second sealing contact surfaces 11a, 12a are in sliding contact with each other.

[0060] The force required to operate the valve assembly is proportional to the axial force applied to the disc:

[0061] Friction force = normal force * friction coefficient

[0062] Since the valve assembly will be integrated into a water dispensing unit (e.g., in the form of a "gun" that the user will hold with only one hand and operate with his thumb over a relatively small range of angular movement), low operating force is crucial. This is unlike similar fluid valves that are driven by a motor, or where the entire hand is used to operate the valve over a large range of angles.

[0063] Therefore, for ergonomic operation, it is crucial to minimize the force required to open and close the valve assembly. To this end, the axial force applied to the discs should be minimized to limit the friction between the discs to a minimum. Extensive testing has shown that water pressure is generally sufficient to press the discs together and achieve a seal without the need for additional force.

[0064] The valve assembly is integrated in Figure 4 In the distribution unit illustrated in FIG, the second disc 12 is arranged as the upper disc and is preferably mounted in free-floating contact with the first disc 11 in order to minimize the operating forces of the water distribution unit. An axial stop is present in the upper manifold to determine and fix the height of the first disc or lower disc and to utilize Figure 4 The custom seal 7a shown in Figure 1 achieves a seal between the first disc 11 and the housing. Subsequently, there is a functional gap between the drive actuator 3 (i.e. the protrusions 3a, 3b in the recesses 18a, 18b of the second disc 12) to ensure that no axial forces are exerted between the discs, other than those due to the fluid pressure acting on the second disc 12 and pressing it against the first disc 11.

[0065] Reduced forces and improved operating ergonomics can be achieved not only by optimizing disk performance and integration with the free-floating second or upper disk, but also by optimizing the rotary seal on the drive actuator.

[0066] In certain applications, it may be beneficial to enhance the sealing effect by slightly biasing the second disk 12 toward the first disk 11 by means of a biasing member (not shown), for example, a resilient member, such as an elastic seal (e.g., an O-ring) or a spring, arranged between the drive actuator 3 and the upper surface of the second disk 12. Such a biasing member may, for example, be arranged in the space between the protrusions 3a, 3b and the upper surface of the second disk 12 (not shown in the figures).

[0067] For the intended use in a liquid dispensing unit for ultrapure water, the disc design and disc performance are optimized to achieve a wide range of flow rates: a good seal must be achieved in the fully closed position and flow rates from stable and easily achievable drop-by-drop dispensing to up to 2 L / min (when the valve assembly is fully open) with limited pressure drop must be provided over a limited ergonomic angle range that allows operation when the liquid dispensing unit is to be used with only one hand and operated with the thumb while the rest of the hand holds the device.

[0068] The size and arrangement of the disc of the valve assembly, in particular the window(s) 13a, 13b, the solid portion 14a, 14b and the opening portion 15a, 15b, are therefore configured to provide a range of rotational angles between a fully closed rotational position and a fully open rotational position which will be between 50° and 70°, preferably between 55° and 65°, and most preferably about 60°.

[0069] The valve assembly 10 is sized to provide a flow rate of from dropwise, preferably 20 mL / min, up to 2 L / min through the at least one window (13a, 13b) within the rotational angle range of relative movement between the fully closed rotational position and the fully open rotational position.

[0070] In particular, in order to provide a stable and easily achievable drop-by-drop dispensing from the fully closed position at the beginning of the operating range (or, although not directly described below, correspondingly from the fully open position towards the end of the operating range), the at least one window 13a, 13b of the first disc 11 has a notch / dent 13e which is recessed into the material of the first disc 11 at one / the edge 13c, 13d of the at least one window 13a, 13b from the plane defined by the first sealing contact surface 11a of the first disc 11, the notch / dent 13e being located at the side where exposure of the at least one window 13a, 13b begins when the second disc 12 moves from the fully closed rotational position in the direction towards the fully open rotational position (see Figure 1 and 3 ). Preferably, only one of the windows 13a, 13b of the first disc 11 has a notch / dent 13e. However, depending on the specific requirements, both windows 13a, 13b or, if the disc 11 has more than two windows, any number of these windows may have such a notch / dent.

[0071] The notch / dent 13e has a sharp tip that gradually and continuously widens in a horizontal direction defined by the extension of the plane of the first sealing contact surface and / or gradually deepens in a direction perpendicular to this plane toward the at least one window 13a, 13b. In other words, the surface of the cross section of the notch / dent 13e increases in the circumferential direction of the first disk 11 toward the at least one window 13a, 13b.

[0072] Furthermore, in order to smooth the flow of liquid when the second disc 12 is further rotated beyond the range of the notch / dent 13e, the at least one window 13a, 13b has an inclination or slope 13f at a side wall adjacent to the side where exposure of the at least one window 13a, 13b begins when the second disc 12 moves from the fully closed rotational position in the direction toward the fully open rotational position, so that the free opening width or surface of the cross-section of the at least one window 13a, 13b in the thickness direction or axial direction of the first disc 11 gradually narrows over at least a certain range with the distance from the plane of the first sealing contact surface 11a.

[0073] As mentioned before, the valve assembly of the present invention is particularly designed and advantageously intended for use in a liquid dispensing unit 1 for a water purification system. The valve arrangement in a preferred embodiment of the liquid dispensing unit 1 is integrated in Figure 4 The liquid dispensing unit 1 in the form of a "gun" to be held by a single hand of a user, with the valve assembly operated by the thumb, comprises a housing 5, a supply conduit 6 for purified water connected to an upwardly directed port 9 of the housing 5, and an outlet 8 for the purified water directed downwardly in a typical upright holding orientation.

[0074] The valve assembly 10 is arranged in the housing 2 of the housing 5 so that the valve assembly 10 can control the amount or rate of flow of purified water from the supply pipe 6 to the outlet 8. The housing 2 communicates with the port 9 and the outlet 8 of the housing 5.

[0075] The first disc 11 of the valve assembly 10 is rotationally fixed in position within the housing 2 (eg, by engaging with locating notches 17a, 17b at the periphery of the first disc 11 (see Figure 1 ) engaging projections or by means of a matching shape of the receiving portion, so that at least one window 13a, 13b is in communication with the outlet 8. The outer periphery of the surface of the first disc surrounding the lower opening of the window(s) is sealed against the housing 5 by means of an annular seal 7a, so that all liquid entering the outlet 8 from the receiving portion 2 must pass through the window(s) 13a, 13b of the first disc 11.

[0076] As described above, second disc 12 is shown mounted in receptacle 2 so as to be in free-floating contact with first disc 11 and with first and second sealing contact surfaces 11a, 12a pressed against each other solely by water pressure from supply conduit 6 acting on second disc 12.

[0077] The second disc 12 of the valve assembly 10 is engaged with a manually operable rotary actuator 3, 4 for rotationally driving the second disc 12 between a fully closed rotational position and a fully open rotational position within the rotational range described above relative to the first disc 11. The rotary actuator includes a shaft 4 and a driver 3 connected to the lower end of the shaft 4.

[0078] Although the driver 3 and the shaft 4 can be made of the same material (i.e., essentially consisting of it), it is preferred that the driver 3 and the shaft 4 are made of different materials. Preferably, the driver 3 is made of (i.e., essentially consisting of) a material having a low content of leachables (i.e., having a low tendency to release contaminants). Non-limiting examples of materials suitable for the driver 3 can be selected from the group consisting of polyacetal and polypropylene. A preferred example of a material suitable for the driver 3 is polyoxymethylene (POM). Preferably, the shaft 4 is made of a material having good mechanical strength (especially torsional strength) to allow accurate and precise operation of the ceramic disc, which is particularly necessary for finding the droplet dispensing position. Non-limiting examples of such materials suitable for the shaft 4 can be selected from polyamide (PA), reinforced (e.g., with fiber reinforcement or talc) polyamide, and reinforced (e.g., with talc) polypropylene. A preferred example of a material suitable for the shaft 4 is polyphthalamide (PPA).

[0079] A portion of the actuator, not shown in the figures, extends to the exterior of the housing 5 and is accessible to the thumb of the hand for operation to rotationally drive the second disc 12 and can be shaped according to desired ergonomics. The rotary actuator is sealed against the housing 5 by an O-ring or gasket 7b to prevent the liquid from escaping the receptacle 2 (except through the outlet 8). The specific design of the actuator is not critical, provided that floating positioning and contact of the second disc relative to the first disc is achieved without introducing additional axial forces associated with the operation of rotating the second disc from the fully closed rotational position to the fully open rotational position (see also FIG. Figure 5 ).

[0080] In an embodiment, the second disk 12 is provided on the outer circumference with additional protrusions 14 c , 14 d , which are inserted into corresponding peripheral grooves 2 a , 2 b of the accommodation portion 2 , so as to guide and limit the rotation range of the second disk 12 .

[0081] In addition to considerations regarding hydraulic performance and usability, the shapes and features of the two trays are optimized for a simple and robust assembly process, wherein the possibility of incorrectly assembling parts in the housing of the liquid dispensing unit is very limited. In particular, the positioning recesses 17a, 17b on the first tray 11 for holding the first tray in place are asymmetrical so as to fit into the housing 2 in which the first tray 11 is integrated in only one position. The asymmetrical ribs 2c, 2d in the housing 2 for holding the first or lower tray 11 in a fixed position also prevent the upper tray from being installed in an incorrect angular position (see Figure 5 ).

[0082] Two protrusions 3a, 3b for engaging with recesses 18a, 18b in the second or moving disk 12 (see Figure 4 ) are also different from each other to allow only one angular position relative to the axis of the actuator. This is important when the stops on the valve (fully open and fully closed) are defined between the shaft and the housing 5.

[0083] The ribs 2e, 2f between the peripheral grooves 2a, 2b of the housing 2 serve to define these stops and therefore also influence the outer shape of the second or mobile disk 12 which should rotate freely over its operating range despite these ribs 2e, 2f.

[0084] The present valve assembly and liquid dispensing unit can be used in applications with different user requirements. For example, a user may want to use the present valve assembly and liquid dispensing unit for "volumetric dispensing," i.e., to dispense a predetermined volume of purified water from the liquid dispensing unit. In such cases, it may be advantageous to preset the valve assembly, as defined herein, to a defined flow rate, using a solenoid valve to open and close the flow of purified water through the supply conduit for purified water, through the valve assembly, as defined herein, to the outlet for purified water. Such a solenoid valve can be actuated using any suitable actuator, such as a foot pedal, which gives the user the freedom to use their hands. Alternatively, the solenoid valve can be actuated by a simple switch or even by a remote control.

[0085] Therefore, the present liquid dispensing unit 1 optionally includes a solenoid valve that controls the flow of purified water through the supply pipe 6 for purified water, through the valve assembly 10 as defined herein, to the outlet 8 for purified water. Such a solenoid valve can be placed at any location that allows controlling the flow of purified water through the supply pipe 6 for purified water, through the valve assembly 10 as defined herein, to the outlet 8 for purified water. For example, a suitable location may be before or at the inlet of the purified water into the supply pipe, or anywhere along the supply pipe 6; preferably, such a solenoid valve is placed before or at the inlet of the purified water into the supply pipe 6.

[0086] Alternatively, such a solenoid valve can also be placed at the dispensing point (ie the outlet 8).

[0087] Of course, the valve assembly can also be rotationally actuated using a motor (preferably a servo motor or a stepper motor). Optionally, such a motor may further include a mechanical gear for reducing the actuation speed. Such a motor is arranged so that it rotates the second disk 12 directly or indirectly (e.g., via a shaft). For example, the motor may be positioned so that it rotationally drives the shaft 4.

[0088] The present liquid dispensing unit can be used as part of a water purification system, in particular a water purification system for providing pure or ultrapure water in a laboratory environment. Therefore, the present application also provides a water purification system comprising such a liquid dispensing unit as defined herein.

Claims

1. A valve assembly (10) for a liquid dispensing unit (1), comprising: A pair of first discs (11) and second discs (12) to be rotated relative to each other, wherein mutually facing first sealing contact surfaces (11a) and second sealing contact surfaces (12a) are arranged to at least partially come into sliding contact with each other, wherein the first plate (11) has at least one window (13a, 13b), and The second disk (12) has a solid portion (14a, 14b) and an opening portion (15a, 15b), wherein the solid portion (14a, 14b) is arranged to completely cover and close the at least one window (13a, 13b) of the first disk (11) in a fully closed rotational position, and the opening portion (15a, 15b) is arranged to at least partially expose the at least one window (13a, 13b) of the first disk (11) in a fully open rotational position.

2. The valve assembly (10) according to claim 1, wherein The solid portion (14a, 14b) of the second disc (12) arranged to completely cover the at least one window (13a, 13b) of the first disc (11) in the fully closed rotational position to close the at least one window (13a, 13b) of the first disc (11) is formed so as to include a portion of the second sealing contact surface (12a), which overlaps the first sealing contact surface (11a) of the first disc (11) surrounding the edge (13c, 13d) of the window (13a, 13b) through a sealing area (16a, 16b) having a width of at least 1.5 mm, preferably at least 2.0 mm.

3. The valve assembly (10) according to claim 1 or claim 2, wherein: The first sealing contact surface (11a) and the second sealing contact surface (12a) of the pair of first disks (11) and second disks (12) arranged to at least partially come into sliding contact with each other have a surface roughness Ra of at most 0.60 μm and / or a surface flatness of at most 0.80 μm, and are preferably polished or ground.

4. The valve assembly (10) according to any one of claims 1 to 3, wherein: The mutually facing first sealing contact surfaces (11a) and second sealing contact surfaces (12a) of the pair of first discs (11) and second discs (12) are arranged so that between the fully closed rotational position and the fully open rotational position, 50% to 80%, preferably 55% to 75%, of the first sealing contact surfaces (11a) and the second sealing contact surfaces (12a) are in sliding contact with each other.

5. The valve assembly (10) according to any one of claims 1 to 4, wherein: The second disc (12) is in free-floating contact with the first disc (11) or is biased toward the first disc (11) by a biasing member.

6. The valve assembly (10) according to any one of claims 1 to 5, wherein: The at least one window (13a, 13b) of the first disk (11) has a notch / dent (13e) recessed from a plane defined by the first sealing contact surface (11a) of the first disk (11) into the material of the first disk (11) at an edge (13c, 13d) of the at least one window (13a, 13b) / the edge (13c, 13d) at the side where exposure of the at least one window (13a, 13b) begins when the second disk (12) moves from the fully closed rotational position in the direction toward the fully open rotational position.

7. The valve assembly (10) according to claim 6, wherein The notch / indentation (13e) has a sharp end that gradually widens and / or deepens towards the at least one window (13a, 13b).

8. The valve assembly (10) according to any one of claims 1 to 7, wherein: The at least one window (13a, 13b) has an inclination or slope (13f) at a side wall adjacent to the side portion / the side portion where the exposure of the at least one window (13a, 13b) begins when the second disk (12) moves from the fully closed rotational position in the direction / the direction toward the fully open rotational position, so that the free opening width of the at least one window (13a, 13b) in the thickness direction of the first disk (11) gradually narrows with the distance from the plane of the first sealing contact surface (11a).

9. The valve assembly (10) according to any one of claims 1 to 8, wherein: The valve assembly (10) is dimensioned to provide a flow rate through the at least one window (13a, 13b) from dropwise, preferably 20 mL / min, up to 2 L / min, within a range of rotational angles of relative movement between the fully closed rotational position and the fully open rotational position.

10. The valve assembly (10) according to any one of claims 1 to 9, wherein: The rotation angle between the fully closed rotation position and the fully open rotation position ranges from 50° to 70°, preferably from 55° to 65°, and most preferably about 60°.

11. The valve assembly (10) according to any one of claims 1 to 10, wherein: The first disc (11) is provided with positioning recesses (17a, 17b) for preventing rotation and defining an installation position in the receiving portion (2) of the liquid dispensing unit (1), wherein the positioning recesses (17a, 17b) are formed and / or arranged asymmetrically with respect to the circumference of the first disc (11).

12. The valve assembly (10) according to any one of claims 1 to 11, wherein: The second disc (12) is provided with one or more driver recesses (18a, 18b) and / or protrusions on a side opposite to the second sealing contact surface (12a) for engaging with a rotary actuator (3) of the liquid dispensing unit (1).

13. The valve assembly (10) according to any one of claims 1 to 12, wherein: The first disk (11) has a circular outer circumference, and the second disk (12) has a non-circular outer circumference, wherein the opening portion (15a, 15b) is arranged to at least partially expose the at least one window (13a, 13b) of the first disk (11) radially recessed from the outer circumference.

14. The valve assembly (10) according to any one of claims 1 to 13, wherein: The first disk (11) and / or the second disk (12) are made of ceramic material, preferably alumina ceramic.

15. A liquid dispensing unit (1) for a water purification system, comprising: a supply pipe for purified water (6); an outlet (8) for purified water; as well as The valve assembly (10) according to any one of claims 1 to 14 is arranged in the receiving portion (2) of the housing (5) so that the valve assembly (10) can control the amount or rate of flow of purified water from the supply pipe (6) to the outlet (8).

16. The liquid dispensing unit (1) according to claim 15, wherein The first disc (11) of the valve assembly (10) is rotationally fixed in position within the housing (2) such that the at least one window (13a, 13b) communicates with the outlet (8), and the second disc (12) is mounted within the housing (2) so as to be in free-floating contact with the first disc (11) and such that the first sealing contact surface (11a) and the second sealing contact surface (12a) are pressed against each other by water pressure from the supply pipe (6) acting on the second disc (12).

17. The liquid dispensing unit (1) according to claim 15 or claim 16, wherein The second disc (12) of the valve assembly (10) is engaged with a manually operable rotary actuator (3, 4) for rotationally driving the second disc (12) relative to the first disc (11) between the fully closed rotational position and the fully open rotational position.

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