A DEVICE FOR SLIDING VALVES, PARTICULARLY FOR MIXING FAUCETS

Abstract: A mixing faucet with two cooperating valve plates (17,18) for controlling the throughflow quantity and/or mixing ratio of the liquids. For reducing the armature sound level at narrow control slots (25) between the two valve plates (17), (18) it is suggested that guiding members (24) are arranged at least in the area in front of the inlet openings (19,20) in the longitudinal direction of the flow passage duct, i.e. in the direction from the inlet openings towards the outlet opening, which guiding members cause the liquid or the liquids to flow laminarly through the flow passage duct.

Description: A device for sliding valves, particularly for mixing faucets The present invention relates to a device for sliding valves, particularly for mixing faucets of the kind comprising two valve plates, which are engaging each other, one of which valve plates is fixed and provided with inlet openings and an outlet opening, and the other being movable relative to the first one and provided with a flow passage duct for adjusting the flow and/or the mixing ratio of the liquids. Background of the invention In previously known valves of the kind mentioned above the movable valve plate is controlled by means of a control lever. The valve plates are favourably made of a ceramic material, whose surfaces facing each other are polished so that no sealing devices are needed. At narrow control slots however, i.e. at flow through a narrow slot, troublesome acoustic phenomena will occur. Several factors influence the formation of sounds from the fittings, i.e. the through-flow quantity, the construction of the mixing valve, the size of the control slot, cavitation, the sealing plate's tendency to vibrate, the use of flow resistances etc. The size of the control slot has for example a large influence on the resulting sound, since the flow velocity in the slot increases the smaller the slot is. The increase of the throughflow will also cause a considerable increase of the high frequency part of the sound, which therefore seems even more disturbing. Without making any actions, the sound level may reach 30-35 dB(A) for a certain through-flow quantity. Oxygen in the water is released at the high flow velocities, which occur when the control slot is narrow, and slot cavitation occurs and the beam entering the mixing chamber will have unstable magnitude and direction, resulting in sound effect generating phenomena. Authorities who stipulate the allowable sound level for outlet armatures, have subdivided the armatures in different classes I-III, and different groups A-C, where the sound level for armature group I may be equal to or less than 20 dB(A) at 3 bar and for armature group II equal to or less than 30 dB(A) at 3 kPa. If the group in question also shall belong to class A, the through-flow is allowed to be equal to or less than 15 1/mien (or 0,25 1/s) at the same pressure, while for class B the corresponding value is 25 1/mien (or 0,42 l/s). It is of course desired by all armature manufacturers to be placed in group I and class A, which however until now has been almost impossible for the kind of armature in question. In the constructions known so far these problems have been approached one by one. In the German Patent appln. 23.56.326 it is described how the flow passage duct is provided with one or more screens. In the German OS 23.56.211 it is described how a screen like the one mentioned above is used together with an airfilled elastic body. With screens of the kind used in these two constructions good noise reducing properties can be achieved, but a drawback is that particles in the water will clog the screens and the noise reducing properties will be lost after some time. The US Patent 4.157.099 descibes at least one protrution in the flow passage duct combined with a plurality of overlapping screens. In the German Patent appl. 26.58.024 it is described how the surfaces of the flow passage duct may be provided with different structures like corrugations etc. These two constructions does however rather increase the turbulence than they stabilize the flow. It has furthermore been tried to attenuate the sound by carefully rounding off the edges of the mixing chamber, always aiming at damping the noise. Also combinations of the actions mentioned above have occurred, together with the introduction of fixed resistors adapted for a certain flow quantity. Purpose and most important features of the invention The purpose of the present invention is to achieve a simple, reliable and cheap construction, that presents a silent f;Low resistance which at the same time changes simultaneously with the size of the control slot, but also stabilizes the flow entering the flow passage duct. These problems have been solved by arranging guiding members at least in the area in front of the inlet openings in the longitudinal direction of the flow passage duct, i.e. in the direction from the inlet openings towards the outlet opening, which guiding members cause the liquid or the liquids to flow laminarly through the flow passage duct. Description of the drawings Figure 1 shows a section through a mixing faucet, e.g. a wash-basin mixer which is provided with a device according to the invention. Figure 2 shows a section through the valve plates in the mixing faucet. Figures 3, 4 and 5 show the valve plates of figure 2 in view from above and in different relative positions. Figure 6 shows a section along line IV-IV of figure 4. Figure 7 shows in perspective view an alternative embodiment of the guiding means. Description of the preferred embodiment The mixing faucet shown in figure 1 is of the so called single lever operated type and comprises a valve housing 11 with a spout 12 and a control lever 13, by which, on one hand, the upper part of the mixing housing 14 is rotatable around a vertical axis, and on the other hand is tiltable around a horizontal axis 15. The lever 13 can be thought of as a two-armed lever, which is journalled around a vertical as well as around a horizonal axis and the shorter lever arm 16 which acts upon a movable valve plate 17. This engages a second fixed valve plate 18, which is provided with two inlet openings 19, 20 for cold and hot water respectively, and an outlet opening 21, which communicates with the spout 12 through a duct 22. The movable valve plate 17 is provided with a flow-passage duct 23 formed therein, in which duct are arranged guiding members 24, which in the embodiment shown in fig. 2-6 are formed by thin sheets arranged in parallel and extending over substantially the entire depth and length of the duct, and at least in the region at the inlet openings 19,20 extending all the way to the flat side 10 of the valve plate 18. The depth of the flow passage duct 23 is conveniently chosen so that the sheets 24 have a reasonably larger extension in the depth dimension than their thickness and spacing. By providing the flow passage duct 23 with very narrow but deep ducts as seen in the flow direction of the liquds, a correspondingly small number of ducts 25 between the sheets 24 will be activated as shown for example in figure 5 where the inlet opening 19 expose only a very little control slot. The extension and resistance of the ducts 25 are matched to the size of every apropriate control slot, and to the entering water quantity determined thereby. The flow entering through the control slot is catched in the exposed ducts 25 and will thereby achieve a controlled stable flow into the control slot and a steady laminar flow through the ducts 25. At an increased control slot opening i.e. at increased flow, more and more ducts 25 will gradually be exposed. Practical tests and measurement of sound levels at the mixer according to the invention have shown that at a flow of about 0,15 liter per second and a pressure drop of 300 kPa, the. sound level from the armature without guiding organs was about 30 dB(A) while it has been possible to decrease the sound level to about 15 dB(A) with guiding members according to the invention. For comparison it can be mentioned that it with the above mentioned devices for decreasing the armature sound level such as screens, rubber dampers, bottom structure design etc. was possible to decrease the sound level of the armature only to 25 dB(A) according to our measurements. It is not necessary that the guiding members i.e. the sheets 24 extend over the entire length of the flow passage duct and as can be seen from figure 2 the sheets 24 may in front of the outlet opening 21 be provided with a concavity 26 where a first mixing of the liquids may occure. It may also be convenient that the depths of the ducts 25 increase as seen from the inlet openings 19, 20, which is also shown in figure 2. It is also possible to design the ducts 25 with a cross-section increasing in a direction towards the outlet opening 21 i.e. the sheets 24 diverge in a direction from the inlet openings 19, 20 towards the outlet openings 21. In the embodiment shown in figures 1-6 the sheets 24 constitute an integrated part of the valve plate 17. If the valve plate is made of ceramic material it is thus convenient that the sheets also constitute one piece with the valve plate. The same advantageous effect may however be achieved if the guiding members 24 constitute a separate part that is loosely inserted into the flow passage duct 23. This guiding means may for instance be made of a suitable plastic material, where the sheets are connected to 'each other by a base plate 27 which has substantially the same shape as the bottom surface of the flow passage duct 23. The invention is not limited to the embodiments shown, but a number of variations are possible within the scope of the claims.

Claims: Claims 1. Device for sliding valves, particularly for mixing faucets of the kind comprising two valve plates (17,1,8), which are engaging each other, one of which valve plates (18) is fixed and provided with inlet openings (19,20) and one outlet opening (21), and the other one (17) being movable relative to the first one and provided with a flow passage duct (23) for adjusting the flow and/or the mixing of the liquids, characterized thereby that guiding members (24) are arranged at least in the area in front of the inlet openings (19,20) in the longitudinal direction of the flow passage duct (23), i.e. in the direction from the inlet openings (19,20) towards the outlet opening (21), which guiding members (24) consist of thin sheets extending over substantially the entire depth of the flow passage duct (23) and being adapted to cause the liquid or the liquids to flow laminarly through the mentioned flow passage duct. 2. Device according to claim 1, c h a r a c t e r i. z e d t h e r e b y that the sheets (24) have a considerably larger extension in the depth dimension of the flow passage duct (23) than their thickness and spacing. 3. Device according to claims 1, or 2, characterized thereby that the sheets (24) are arranged parallel to each other. 4. Device according to claims 1, or 2, characterized thereby that the sheets (24) are arranged to converge in a direction from the inlet openings (19, 20) towards the outlet opening (21). 5. Device according to one or more of the prerceding claims, characterized thereby that the sheets (24) partly are arranged to extend over the entire length of the flow passage duct (23), partly to the upper edge of the movable valve plate (17) in the area in front of the inlet openings (19, 20), and partly to a level somewhat below the upper edge of the movable valve plate (17) in front of the outlet opening (21). 6. Device according to any of the preceding claims, characterized thereby that the sheets (24) are integral with constitute one piece with the movable valve plate (17). 7. Device according to any of the previous claims 1-5, characterized thereby that the sheets (24) are interconnected via a base plate (27) which has substantially the same shape as the flow passage duct (23).

Inventors: RIIS, VALDEMAR
Applicants: VAERGAARDA ARMATURFAB AB
Application year: 1982
Main classification: F16K11
IPC codes: F16K47, F16K11