Thermostatic mixing valve

Abstract

The invention relates to a thermostatic mixing valve in which in a bottom base and in the ceramic disks (4, 5) of the valve group there are obtained a hot water access path to the mixing chamber and an additional cold water path with an opening independent of the thermostatic device activation, by rotation of the flow control in a direction opposite to the opening of the water path regulated by the thermostatic device.

Description

[0001] THERMOSTATIC MIXING VALVE

[0002] The present invention relates to taps for mixing hot and cold water in sanitary facilities (wash-basins, showers, bathtubs, etc.), and in particular to a cartridge mixing valve provided with a thermostatic device suitable to maintain a constant water temperature.

[0003] It is known that conventional single-control mixing taps include a tap body with a cartridge mixing valve (hereinafter simply valve) removably inserted therein and a control lever for controlling a valve group, within the cartridge, made up of a pair of ceramic disks which adjust the flow of hot and cold water. This adjustment of the water, both in flow rate and in temperature, is carried out through the translation and rotation, respectively, of a mobile disk over an underlying fixed disk. In this way, the extent of aperture of the ports formed in said disks for the passage of hot and cold water is changed, and so is the ratio between hot water and cold water when they are mixed prior to the conveying to the tap mouth.

[0004] In order to maintain a constant temperature of the delivered water, both between two tap openings and during a same opening, it is possible to incorporate a thermostatic device in a conventional tap. Such a device acts downstream from the valve group by controlling the inflow of hot and cold water into the mixing chamber through respective ports. EP 0611260 is an example of such a conventional mixing tap with a thermostatic device.

[0005] As it will be better explained further on, this control is carried out automatically by a thermosensitive bulb which causes the shifting of a slider suitable to change the aperture of said ports in the mixing chamber. However, although known from some time, conventional thermostatic mixing valves still have some drawbacks of various nature:

[0006] - the asymmetric thermal expansion that occurs when only hot water is delivered;

[0007] - the calcareous encrustations, especially on the hot water side, which may jeopardize the correct operation of the device;

[0008] - the use of a single control for temperature and flow rate, that implies a difficult repeatability of temperature between two openings, as well as a poor precision in adjusting the temperature due to the limited travel of the single control; - as an alternative to the preceding point, the need to separate the flow rate control from the temperature control by placing the thermostatic device above the valve group to achieve a more precise adjustment of temperature through the rotation of a ring along a greater arc (up to 360°), and also without any problem of repeatability between two openings, which however results in a tap having a greater overall height and makes it difficult to reach the ring for the temperature adjustment. Furthermore, the flow rate adjustment is transmitted by a connection which passes through the thermostatic device, which is possibly used directly as a transmission means, and the more or less close coupling between the flow rate control and the temperature control leads to a mutual interference which may affect the device operation, and also the thermostatic device is stressed by loads not depending on its specific operation.

[0009] To overcome these drawbacks, the applicant has already patented an improved valve described in WO 2005 / 054971, to which reference is made for a detailed description of the structure of this valve and its advantages. However, even this known valve has drawbacks with regard to cold water supply.

[0010] In fact, if the user needs to deliver only cold water this requires a change in the temperature setting on the thermostatic device, which must then be reset to the normal temperature of use when the cold water delivery is completed. Alternatively, the user could take advantage of the response delay of the hot water delivery system, since cold water is always delivered at the initial stage of opening the tap regardless of the set temperature, but even this option has a twofold drawback: first, the limited amount of cold water delivered before the water temperature rises, and second, the waste of energy in activating the heater that takes place immediately as soon as the tap is opened.

[0011] It is therefore an object of the present invention to provide a thermostatic mixing valve that overcomes the above drawbacks. This object is achieved by means of a valve in which an additional cold water inlet / adjustment / supply path with independent opening by rotation of the flow control in the opposite direction from the opening of the traditional thermoregulated water path is obtained in a bottom base and in the two ceramic disks of the valve group. The main advantage of the present valve is to allow cold water to be delivered independently of thermoregulated water, so that the user can choose which of the two tap functions to use.

[0012] A second advantage of the valve according to the present invention, in an alternative embodiment thereof, is to have a separate outlet for cold water that can feed a secondary tap outlet.

[0013] A further advantage of the valve according to the present invention is that it is made with an external structure that is substantially unchanged from the previous version described in WO 2005 / 054971, so that the latter can be easily replaced with the present updated version.

[0014] These and other advantages and features of the valve according to the present invention will be apparent to those skilled in the art from the following detailed description of an embodiment thereof with reference to the attached drawings in which:

[0015] Fig.1 is an exploded side view of the elements comprising said valve, some of which are in semi-section and others in section;

[0016] Fig.2 is a schematic side view in section showing the elements of Fig.1 in assembled condition;

[0017] Fig.3 is a perspective view from below of the two ceramic disks of the valve group;

[0018] Fig.4 is a top view of the lower disk;

[0019] Fig.5 is a perspective view from below of the upper disk;

[0020] Fig.6 is a top view of the upper disk;

[0021] Fig.7 is a top view of the bottom base with a related gasket;

[0022] Fig.8 is a side view of the flow control and its transmission element rotated to the cold water opening position;

[0023] Fig.9 is a side view of the valve group and base in the position corresponding to Fig.8;

[0024] Fig.10 is a sectional view along the A-A line of Fig.9;

[0025] Fig.l 1 is a top view of the valve group of Fig.9;

[0026] Fig.12 is a sectional view along the B-B line of Fig.11;

[0027] Fig.13 is a sectional view along the C-C line of Fig.11; Fig.14 is a side view of the flow control and its transmission element rotated to the thermoregulated water opening position;

[0028] Fig.15 is a side view of the valve group and base in the position corresponding to Fig.14; and

[0029] Fig.16 is a sectional view along the D-D line of Fig.15.

[0030] Since, as mentioned earlier, the present thermostatic valve is an evolution of the previous version described in WO 2005 / 054971, for ease of reference, Figs.l and 2 and the related description part of that document are given here, so that it is easier to understand the changes and innovations from that known valve.

[0031] These figures show that a valve according to the present invention includes a valve group, described in greater detail further on, consisting of a mobile upper disk 5, a fixed lower disk 4, a lower gasket 3 and a base 2, below which a relevant gasket 1 is arranged for the mounting into the tap body. In base 2 there are formed lateral openings C, F for the inflow of hot and cold water, respectively, and the central opening M for the outflow of the mixed water.

[0032] Inside the valve group there are arranged a lower spring 6 pushing from below a slider 8 that sealingly slides, thanks to an O-ring 7, in disk 5 and is pushed from above by a thermostatic member 9 passing through it. On the latter there is screwed an insert 10 that, thanks to an O-ring 11, is sealingly introduced in the central opening of a member 13 that transmits the flow rate control.

[0033] Also the top face of the upper disk 5 is sealed, thanks to an O-ring 12, against said member 13, so that the water is restrained below member 13. In this way the water pressure cannot interfere with the operation of the temperature and flow rate controls located in the top portion of the valve.

[0034] The operation of the thermostatic device of the present valve is similar to that of conventional thermostatic valves and is based on the thermostatic member 9 which, according to the mixed water temperature detected by the bottom bulb, causes the shifting of slider 8 within the transmission member 13 and the upper disk 5. Due to the push of the upper rod against a cap 15 secured, by means of a retaining ring 14, inside an adjusting bar 17 and pushed downwards by a spring 16, the thermostatic member 9 shifts slider 8 so as to change the extent of aperture of the inflow ports of the hot and cold water. These ports are formed, respectively, between the lower edge of slider 8 and the upper edge of base 2, within the upper disk 5, and between the upper edge of slider 8 and the transmission member 13.

[0035] The position of the adjusting bar 17, and therefore the compression of the lower spring 6, is set by rotating, through a non-illustrated knob, a temperature control member 18 which is screwed on the top portion of bar 17.

[0036] The temperature control member 18 projects from a housing body 19, which encloses the above-described elements and is coupled to base 2, and is axially locked on said housing body 19 by a retaining ring 22. Similarly, a flow rate control member 20 is inserted on the outside of body 19 and axially locked thereon by a retaining ring 21.

[0037] Member 20 externally engages the transmission member 13 by passing through suitable slots formed in body 19; on the latter there is also formed a grooved surface, above a similar grooved surface of member 20, to secure a fixed reference member for the setting of the temperature through member 18.

[0038] Referring now also to Figures 3 and 4, it can be seen that the lower fixed disk 4 is traditionally provided with three water passage ports 4c, 4f, and 4m for hot, cold, and mixed water, respectively, as well as a plurality of side recesses 4a (three in the example shown) to be locked into base 2. The innovative aspect of disk 4 according to the present invention lies in the presence of an additional passage 4b for cold water bypass. Such a passage 4b preferably has a greater angular extension in the part that opens on the top face of disk 4 than in the part that opens on the bottom face of disk 4, as best illustrated in Fig.12.

[0039] The mobile upper disk 5, shown in Figures 5 and 6, also has similar side recesses 5a (three in the example shown) to be controlled in rotation by element 13 through corresponding stems, as well as ports 5f, 5m for the passage of cold and mixed water, respectively. More specifically, in practice, port 5m does not act as a passage for mixed water but as a sliding seat for slider 8, and hot water port 5c extends with an essentially cam-like shape over about 180° and does not reach the upper face of the disk.

[0040] In other words, port 5c is not a real port but a chamber formed on the bottom face of disk 5, and it extends on the side of disk 5 opposite to that where port 5f is made. The cam profile makes it possible to achieve the progressive closure of port 4c to regulate the flow rate of hot water, which does not pass through slider 8 but flows immediately into base 2 mixing with the cold water coming from above.

[0041] The innovative aspect of disk 5 according to the present invention lies in the presence of a blind slot 5b formed on the lower face of disk 5, with such an extension and position as to overlap with the cold water passage 4f and the bypass passage 4b of disk 4 so as to act as a connection between said passages, as best illustrated in Figures 10-12.

[0042] Finally, the novel aspect of base 2 according to the present invention, shown in Fig.7, lies in the presence of an additional cold water bypass passage 2b, which preferably has a greater angular extension in the part opening on the top face of base 2 than in the part opening on the bottom face of base 2. Said passage 2b is obtained in such a position as to receive the cold water outflow from passage 4b and in turn is connected to the central opening M, as best illustrated in Figures 12 and 13.

[0043] The simple and effective operation of the present thermostatic valve is therefore readily understandable in the light of the above description with reference also to Figures 8-13. In the position shown in those figures, the flow control 20 has been rotated in one direction, e.g., to the left in Fig.8, starting from the tap closed position (STOP), dragging the transmission element 13 and the upper disk 5 in rotation as well so that the latter reaches the position shown in Figures 10-12.

[0044] In this way, the blind slot 5b is arranged to straddle passage 4f and passage 4b to allow cold water to enter through opening F in base 2, but without passing the upper disk 5 since passage 5f remains closed. From passage 4b, water flows out into the underlying passage 2b and finally through the central opening M to be delivered from the tap mouth (Fig.13). The adjustment of the flow rate obviously results from the degree of overlap between slot 5b and passage 4f.

[0045] In an alternative embodiment, not shown in the figures, passage 2b could lead to a separate outlet instead of the central opening M, so that the tap could have two separate outlets for cold water and mixed water.

[0046] For comparison, Figures 14-16 show the position for the delivery of mixed water. In the position shown in those figures, the flow control 20 has been rotated in the opposite direction, e.g., to the right in Fig.14, starting from the tap closed position (STOP), also dragging the transmission element 13 and the upper disk 5 in rotation so that the latter reaches the position shown in Figures 15-16.

[0047] In this way, passage 5f is superimposed on passage 4f, while chamber 5c is superimposed on passage 4c and the mixing function of hot and cold water is achieved as shown in the section of Fig.2, while slot 5b is not superimposed on passage 4f.

[0048] It is therefore apparent that this improved version of the valve described in WO 2005 / 054971 provides a convenient additional function of direct cold water delivery while retaining all the advantages of the previous version:

[0049] - no problems with thermal expansion and calcareous encrustations at the top of the valve;

[0050] - fully independent temperature (6, 14-18) and flow (13, 20) controls, with the latter acting directly on the mobile disk 5 without dragging other elements;

[0051] - short valve consisting of only 22 parts, of which there are only 11 parts to be custom- made in metal, plastic or ceramic, resulting in a significant manufacturing cost advantage;

[0052] - possibility of further reducing the number of pieces by making insert 10 integral with element 9, or the fixed disk 4 integral with base 2 dispensing with gasket 3.

[0053] It is clear that the above-described and illustrated embodiment of the valve according to the invention is just an example susceptible of various modifications. For example, the exact shape and number of the members enclosed within housing 19 may be changed, in particular disks 4, 5 as well as base 2 as previously mentioned. Furthermore, all the members may be replaced by other mechanically equivalent members, such as recesses 4a and 5a which may be other types of rotational couplings.

[0054] Finally, the hot water chamber 5c can also be formed partly or completely in the top face of the fixed disk 4, reducing the height of the mobile disk 5 proportionally.

Claims

CLAIMS1. Thermostatic mixing valve comprising: a bottom base (2) provided with two lateral openings (C, F) for the inflow of hot and cold water, respectively, and a central opening (M) for the outflow of mixed water, a valve group with overlapping ceramic disks (4, 5) provided with ports (4c, 4f, 4m, 5f) and with the upper disk (5) mobile with respect to the lower disk (4) so as to adjust the flow rate of hot and cold water, a mixing chamber to which hot and cold water arrive through respective access paths, wherein the access path of the hot water is completely formed within said bottom base (2) and said ceramic disks (4, 5) whereas the access path of the cold water passes through said upper disk (5), a thermostatic device including a thermostatic member (9), a slider (8) that sealingly slides in a central seat (5m) of the upper disk (5), and a resilient contrast means (6) which are mobile within said mixing chamber, couplings for separate controls for adjusting the flow rate, through said valve group, and the temperature through said thermostatic device, characterized in that in the bottom base (2) and in the ceramic disks (4, 5) there is formed an additional path of cold water that does not pass through the upper disk (5) and with opening independent of the activation of the thermostatic device, by rotation of the coupling of the flow rate adjustment control in a direction opposite to the opening of the water path regulated by the thermostatic device.

2. Thermostatic mixing valve according to claim 1, characterized in that said additional cold water path includes a port (4b) for the bypass of cold water formed in the lower disk (4) close to a cold water port (4f), a blind slot (5b) formed in the bottom face of the upper disk (5) with an extension and position such as to overlap said bypass port (4b) and said cold water port (4f) of the lower disk (4) so as to connect said ports (4b, 4f), and a bypass port (2b) formed in the bottom base (2) at such a position as to receive the cold water exiting the bypass port (4b) of the lower disk (4) and in turn connected to a central opening (M) used also for the delivery of the mixed water or connected to a specific opening for the delivery of the cold water.

3. Thermostatic mixing valve according to claim 2, characterized in that the bypass port (4b) formed in the lower disk (4) has an angular extension greater in the portion opening in the top face than in the portion opening in the bottom face of the lower disk (4).

4. Thermostatic mixing valve according to claim 2 or 3, characterized in that the bypass port (2b) formed in the bottom base (2) has an angular extension greater in the portion opening in the top face than in the portion opening in the bottom face of the bottom base (2).

5. Thermostatic mixing valve according to any of the preceding claims, characterized in that the lower disk (4) is integral with the bottom base (2).

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