A SINGLE HANDLE MIXING VALVE HAVING A HYDRAULIC RESPONSIVE MEMBER PRESSING THE CARTRIDGE

Abstract: A mixing valve including a valve body (1), control means (25-27) a changeable cartridge (10) housing a fixed hard material plaque (18) and at least one movable hard material plaque (19) intended to cooperate with the fixed plaque under action of the control means (25-27) in order to regulate the flow rate and the mixing ratio of the valve, and with a hydraulic responsive member (50) acting as a piston, sealingly inserted with axial mobility in a corresponding bore of the valve body (1), between the valve bottom (1A) and a chamber for the cartridge (10). The hydraulic responsive member (50) has passages (51, 52) therethrough in communication with water inlets (7A, 8A) of the body (1) and also in communication with entrances in the cartridge (10); furthermore, the hydraulic responsive member (50) has surfaces which undergo the pressure of inlet (52), and a spring member (30) is interposed between the valve body (1A) and the hydraulic responsive member (50). This member thus charges the cartridge (10) with a force which, in any circumstance, is suitable for avoiding removal of the plaques (18, 19) the one from another or from their packings, and the positions of the inlets (7A, 8A) are made independent from the positions of the entrances of cartridge (10).

Description: DESCRIPTION A SINGLE HANDLE MIXING VALVE HAVING A HYDRAULIC RESPONSIVE MEMBER PRESSING THE CARTRIDGE TECHNICAL FIELD This invention relates to a mixing valve comprising a valve body with inlets for hot and cold water, at least one outlet for mixed water and an inner chamber for housing a cartridge, control means, a replacea¬ ble cartridge inserted in said chamber of the valve body, a fixed plaque of hard material having water passages mounted in said cartridge and at least a movable plaque housed in said cartridge, connected to said con¬ trol means and intended to cooperate with said fixed plaque in order to regulate the water flow delivered to the outlet and the mixing ratio between hot and cold water. BACKGROUND OF THE INVENTION Valves that incorporate sliding hard material plaques, commonly of ceramic, are well known and have many advantages over other types of valves: the hard material plaques are durable and provide for a long li¬ fe with virtually no leakage between the two highly polished valving surfaces of the plaques. However, in order to operate an effective clo- sure, the fixed and movable plaques of such valves should be pressed against the one another and against the respective packings by an adhe¬ sion force adequate to the inlet water pressure, which otherwise could separate the plaques the one from the other or from the respective pack¬ ings, thus rendering ineffective the closure. Commonly, this adhesion compressive force is obtained by having the fixed plaque seated on resi¬ lient elastomeric seals. The upper portion of the valve must have all its elements dimensioned precisely so that the movable plaque will be under compressive force. Manufacturing tolerances have to be within an extremely restricted range in order for the resilient elastomeric seals to function properly. If the total height of the internal valve members is slightly too great the elastomeric seals become excessively compres¬ sed and the plaques are pressed against each other with too great a for¬ ce and are therefore hard to operate, or even are blocked. On the other hand, if the total height of the internal valve members is slightly too little, the resilient elastomeric seals do not adequately press the two plaques together so that leakage may occur, not only, but the elastome¬ ric seals may even be displaced out from their seatings, thus requiring dismounting and repairing the valve. The action of thermal expansion of the components may be sufficient to give rise to said inconveniences. DISCLOSURE OF INVENTION The general object of this invention is to provide a simple and ra¬ tional means for applying to the cartridge bottom a force, directed to¬ wards the fixed plaque, adequate to the actual working conditions of the valve, this force being discharged by the fixed plaque, on its turn, on¬ to the movable plaque and thus also providing the needed adhesion force applied to the pair of plaques of the valve. A more specific object of the invention is to provide a valve of the type referred to, wherein an adhesion force adequate to any circumstance may be applied to the pair of plaques of the valve, tough not necessari¬ ly requiring for the cartridge to have specific shape or features, whe¬ reby it is possible to insert in such a valve the conventional cartrid¬ ges manufactured for usual valves. These objects are attained, according to the invention, by the fact that a valve having the features stated in the preamble further compris¬ es a hydraulic responsive member, acting as a piston, sealingly inserted with axial mobility in at least a corresponding bore of the valve body between the body bottom and said chamber intended to house the cartrid¬ ge, said hydraulic responsive member having fluid passages which are sealingly connected with the inlets of said body and open on the face of the hydraulic responsive member facing the chamber for the cartridge in order to supply hot and cold water to the water passages of said fixed plaque, said hydraulic responsive member having at least a surface ex¬ posed to the water pressure of at least one of said body inlets. Prefe¬ rably, in addition, a spring means is inserted between the valve body bottom and the hydraulic responsive member in order to apply to the lat¬ ter a force directed towards the chamber which houses the cartridge. Thanks to these characteristics, the hydraulic responsive member ap¬ plies to the cartridge a force proportional to the water pressure, due to said surface of the hydraulic responsive member exposed to the water pressure, as well as, if the case may be, a preloading force caused by said spring means. By a suitable design of the components, the total force applied to the pair of plaques and to the respective packings may be rendered sufficient for ensuring, in any working condition, a correct adhesion between said components, though at the same time avoiding ap- plication of unnecessarily great forces. In many cases a correct design allows to attain this behaviour even without providing spring means, however these latter can be provided whenever useful. Moreover, the hy¬ draulic responsive member also provides, by its passages, a connection of the body inlets to the cartridge entrances for hot and cold water, and since various shapes may be given to said passages the positions of the body inlets are rendered at a large extent independent from the po¬ sitions of the cartridge entrances for hot and cold water, thus allowing a more free design of the valve body. According to a specific embodiment of the invention, the hydraulic responsive member is provided with two projections sealingly inserted in corresponding seatings of the valve body, communicating with the water inlets, the total active surface of said projections, which undergoes a hydraulic pressure directed towards the cartridge, being greater than the total active surface of the hydraulic responsive member which under- goes a hydraulic pressure aiming to remove said hydraulic responsive member from the fixed plaque of the valve; the hydraulic responsive mem¬ ber may be formed by the bottom of the cartridge itself. BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics and advantages of the invention will be more clearly apparent from the following description of some embodi¬ ments, given as non limiting examples, diagram atically shown in the ap- pended drawings in which: Figures 1 to 4 are side elevational views of axial sections taken through four embodiments of the invention; Figure 5 shows a cross section taken perpendicularly to the valve axis, in register with the body inlets of any valve whatever .of figures 1 to 3; Figure 6 showh the axial section of a further embodiment of the in¬ vention; and Figure 7 is an axial view from inside of the bottom of the cartridge envelope of the valve according to figure 6, housing the seals for the fixed plate. BEST MODES FOR CARRYING OUT THE INVENTION Referring now to Figs. 1 to 3 and 5, a valve according to the inven¬ tion includes a body 1 provided with two inlet connections 7A and 8A for hot and cold water respectively, and with a mixed water outlet 40B. The body 1 has a bore intended for receiving a hydraulic responsive member acting as a piston, described later on, and this bore expands towards the body opening thus forming a hollow chamber 2 which is adapted to re¬ ceive a cartridge 10 as well as to collect the mixed water. Mixed water is then sent to the outlet 40B through a passage 39 shown in figure 5. The opening of body 1 is occluded by a cap member 5, which may for exam¬ ple be screwed, has a seal packing and holds a half-bearing 23 wherein there is seated a ball 25 serving as pivot for a control lever 26 having an inner arm 27 which operates the mechanisms of a cartridge 10 inserted into the body 1. The cartridge 10 may be of a conventional type, usually intended for valves of a type not embodying the invention, and includes an envelope 10, usually of plastics, a fixed hard material plaque 18 seated within the envelope 10 and provided with passage openings for hot and cold wa¬ ter, and a movable hard material plaque 19 positioned on the fixed pla¬ que 18 and movable by a control head 20 which in turn is guided by a ring 21 and is operated by arm 27. The control head 20 rests against a half bearing 22 which completes the seating for ball 24 and compresses a seal 24, the entity of whose compression is defined by the half-bearing 22 resting against cap member 5. Resilient elastomeric seals are dis¬ posed on the bottom of the cartridge envelope 10, towards the inside for the fixed plaque 18 and towards the outside for sealing with respect to the valve body, and more precisely, in this case, with the hydraulic responsive member to be described later on. It is recognized that the cartridge 10 is conventional in structure and that the operation thereof is also conventional and well known and does not require further expli- cation. With reference to figure 1, a hydraulic responsive member 50 in the form of a piston is positioned within the bore of body 1 for axial move¬ ment therein. The hydraulic responsive member 50 is interposed between the chamber 2 for cartridge 10 and the bottom 1A of body 1 and has two passages 51 and 52 designed for communicating the inlets 7a and 8a of body I with two entrances of the cartridge 10 corresponding to the pas¬ sage openings of the fixed plaque 18. The seal between each passage 51, 52 and the corresponding inlet 7A, 8A is given by packings 53, 54, while a peripheral packing 55 seals the piston 50 with respect of the bore of body 1. A passage 56 through piston 50 connects one of the passages, in this case passage 52, to a chamber 57 formed between the piston 50 and the bottom 1A of the body 1, which chamber, therefore, communicates with one of the inlets 7A, 8A, in this case with inlet 8A. A spring 30 is mounted between the piston 50 and the bottom 1A and is compressed there- between. The assembly of the mixing valve (made when there is not yet water inlet pressure) has the spring 30 and the piston 50 dropped into the bo- re of body 1; the cartridge 10 is then placed within the chamber 2 along with all the controlling, driving and sealing members, and a cap 5 is screwed into position forcing the cartridge 10 against the piston 50 and this latter down into the bore, thus compressing the spring 30. The spring 30 causes the piston to bias the cartridge upwardly so that the fixed plaque 18 is compressed against the movable plaque 19; the strenght of spring 30 is selected in order to correspond to the minimum force which prevents leakages at low water pressure. When later on a water pressure is sent to the inlets 7A and 8A, this ; < essure is transmitted through the passage 56 to chamber 57 and it pushes upwards piston 50 to bias the cartridge 10 upwardly and provide a compressive force between the fixed plaque 18 and the movable plaque 19. This force is proportional to the water pressure and it increases the adhesion between the plaques 18 and 19 and between them and the respec- tive packings. The active. surface of piston 30 is suitably chosen in order that the force thus applied to the valve plaques and their pack¬ ings be in any event adequate for a correct operation at the actual ope¬ ration pressure, anyhow this latter may vary. The adhesion is immedia¬ tely increased as well in case of accidental overpressures, due for example to water hammers in the supply pipings. The removal of the pla¬ ques from their contact and the displacement of the packings is thus systematically avoided. A gap 0 provided between the cap 5 and the cartridge envelope 10 al¬ lows for upward movement to a limited degree of the cartridge envelope, connected with the above operation. Gap 0 is so chosen that, by in¬ creasing water pressure, at a certain time the envelope 10 rests against cap 5, thus avoiding further increase of the pressure applied to the inner cartridge parts. A similar gap 0A provided between the piston 50 and the cartridge bottom also allows relative limited movement there- between, to define the compression received by the interposed packing. As shown in figure 5, the passages 51 and 52 of piston 50 can be angled a desired amount and positioned to accommodate different loca- tions of inlets 7A and 8A and different location ' s of the water entrances of the cartridge. Therefore, with the proper construction of piston 50, matching of different valve bodies to different standard cartridges is possible. With reference to figure 2, in the second embodiment piston 50 is formed by an upper part 50A and a lower part 50B. The upper part 50A is provided with the passages 51, 52 and carries the packings 53, 54, and the lower part 50B has the packing 55, the passage 56 and further pack¬ ings for sealing with the upper part 50A. A spring 30A, formed in this case by an elastomeric body, is mounted within the chamber 57 to assist in the upward bias of the piston 50. In this case, the lower part 50B has a diameter less than the upper part 50A, thus forming a stepped pis¬ ton, and the bore in body 1 has correspondingly two different diameters. A stepped piston allows for hydraulic pressure acting on a predetermined area which is independent of the outer diameter of the piston which can be variable to accomodate differently sized cartridges 10, thus allowing optimize the valve design. Furthermore, forming the piston 50 with two separate parts 50A and 50B ensures easier manufacture and allows stan¬ dardization of parts among devices with different arrangements. How- ever, when such advantages are not of interest, the piston parts 50A and 50B can be made integral therewith to form an integral stepped piston which still maintains the predetermined hydraulic responsive area of the piston. Figure 3 shows another modification to the embodiments of figures 1 and 2, wherein the bottom portion 50B of piston 50 is fully made from elastomeric material which provides both for an integral spring means and for sealing the chamber 57. Again, there is a passage 56 that com¬ municates chamber 57 with inlet 8A. The bottom portion 50B could even have a diameter different from that of upper part 50A, as in the case of figure 2. Figure 4 shows an embodiment where the piston 50C is stepped at two different diameters, and of course the corresponding bore in body 1 is also complementarily stepped. ' Seals 60, 61 and-62 of piston 50C are co¬ axially mounted about the piston and the passages 51 and 52 have their inlet ends at different heights and are mutually separated by seal 61. An annular chamber 57A is formed between piston 50C and the bore in body 1C, where these components are stepped, and it is in fluid communication with inlet 8A. Therefore the hydraulic pressure acts on piston 50C on its annular surface provided at the stepping thereof. Furthermore, a closed chamber 59 is formed between piston 50C and bottom 1A of valve body IB, and it contains some air which is entrapped at the time of in- stallation and is then compressed by piston 50C. This compressed air acts as an air spring to give an upward bias onto piston 50C, replacing the spring means 30 or 30A . Alternatively, the chamber adjacent the body bottom 1A can retain its operation as water pressure chamber according to figures 1 to 3, and an air pressure chamber can be provided when the piston and its bore are stepped. The pistons, in all embodiments, can be prevented from rotating in the body 1, if this is deemed suitable, by the introduction of a dowel or other well known engineering technique, substantially in the same way in which the cartridge is usually prevented from rotating. In the particular embodiment shown in figures 6 and 7, the hydraulic responsive member is incorporated with the cartridge bottom. The valve has a body 1 having bottom inlets 7 and 8 for hot and cold water respec¬ tively, which open in register with seatings 3 and 4 of the body bottom. Body 1 has a bore 2 for cartridge 10, whose bottom extends to form pro¬ jecting connections 11 and 12 inserted in seatings 3 and 4 wherein they seal by means of packings 15 and 16. A packing 17 seals between the bo¬ dy of envelope 10 and the fixed plaque 18. A spring 30, formed by a bent disc having two openings for the passage of projections 11 and 12, is inserted between the bottom of cartridge 10 and the bottom of body 1. This spring provides for a constant thrust applied to the cartridge, whereas the hydraulic pressure within the seatings 3 and 4 of body 1 acts onto the projections 11 and 12 of the bottom of cartridge envelope 10, which therefore form a hydraulic responsive member acting as a pis¬ ton. It is needed that the total active surface of said projections, which undergoes a hydraulic pressure directed towards the cartridge, be greater than the total active surface of the hydraulic responsive parts (including the fixed plaque) which undergoes a hydraulic pressure aiming to remove said parts from the movable plaque of the valve. Said hydraulic responsive member formed by the bottom of the cart¬ ridge may be integral with the remaining part of the cartridge envelope, as shown, or even it could be a member separate therefrom. Of course, with this embodiment, in which the hydraulic responsive member is formed by the bottom of the cartridge envelope 10, the cart¬ ridge should have a specific shape and cannot be a conventional valve cartridge. Therefore this embodiment can be used only when there is no problem involved in the use of a specific cartridge, and it does not al¬ low some of the advantages stated with reference to the former embodi¬ ments. In the examples shown a pre-loading spring means is provided in one or another form. However such spring means can be avoided if the pres- sure responsive area of the piston is adequately larger than the area on which the hydraulic pressure acts aiming to separate the plaques and their packings. In effect, a leakage can in this case take place at the time of installation, but in the above conditions the piston will at a later time be pushed up to contact with the cartridge and provides then for a seal, which is successively maintained by the hydraulic pressure.

Claims: CLAIMS 1 . A mixing valve comprising a valve body (1) with inlets (7A,8A) for hot and cold water, at least one outlet (40B) for mixed water and an inner chamber for housing a cartridge (10), control means (25-27), a re- placeable cartridge (10) inserted in said chamber of the valve body (1), a fixed plaque (18) of hard material having water passages mounted in said cartridge (10) and at least a movable plaque (19) housed in said cartridge (10), connected to said control means (25-27) and intended to cooperate with said fixed plaque (18) in order to regulate the water flow delivered to the outlet and the mixing ratio between hot and cold water, characterized in that it further comprises a hydraulic respon¬ sive member (50), acting as a piston, sealingly inserted with axial mo¬ bility in at least a corresponding bore of the valve body (1) between the body bottom (1A) and said chamber intended to house the cartridge (10), said hydraulic responsive member (50) having fluid passages (51, 52) which are sealingly connected with the inlets (7A,8A) of said body and open on the face of the hydraulic responsive member (50) facing the chamber for the cartridge (10) in order to supply hot and cold water to the water passages of said fixed plaque (18), said hydraulic responsive member (50) having at least a surface exposed to the water pressure of at least one of said body inlets. 2 . A mixing valve according to claim 1, characterized in that a spring means (30,30A,50B) is interposed between the valve body bottom (1A) and said hydraulic responsive member (50) for pushing the hydraulic responsive member toward the chamber that contains the cartridge (10). 3. A mixing valve according to claim 1, characterized in that said hydraulic responsive member (50) and the corresponding bore in the valve body (1) have a constant diameter on their whole lenght. 4 . A mixing valve according to claim 1, characterized in that said hydraulic responsive member (50) and the corresponding bore in the valve body (1) are stepped, each having two portions with differing diameters. 5 . A mixing valve according to claim 1, characterized in that a pressure chamber (57) is formed between the valve body bottom (1A) and the hydraulic responsive member (50), this chamber (57) communicating with one of the passages of the hydraulic responsive member (50) through an opening (56) passing through said hydraulic responsive member. 6 . A mixing valve according to claim 4, characterized in that a pressure chamber (57A) is formed between said hydraulic responsive mem¬ ber (50) and the corresponding bore, in that region in which said compo¬ nents are stepped, this chamber (57A) communicating with one of the body inlets (7A,8A). 7. A mixing valve according to claim 2, characterized in that said spring means is formed by a spring (30). 8. A mixing valve according to claim 2, characterized in that sai spring means includes a resilient elastomeric material (30A,50B). 9 . A mixing valve according to claim 2, characterized in that an air pressure inner chamber (59) is formed between the valve body bottom (1A) and the hydraulic responsive member (50), and said spring means is formed by the air contained in said chamber (59), compressed by the hy¬ draulic responsive means (50). 10 . A mixing valve according to claim 2, characterized in that said hydraulic responsive member (50) and the corresponding bore are stepped, each having two portions of differing diameters, and that an air pressu¬ re inner chamber is formed between the hydraulic responsive member (50) and the corresponding bore in that region in which said components are stepped, and said spring means is formed by the air contained in said chamber, compressed by an annular portion of the hydraulic responsive member (50) defined by the stepping thereof. 11 . A mixing valve according to claim I, characterized in that said passages (51,52) of the hydraulic responsive member (50) are so shaped as to make the positions of the inlets (7A,8AMn the valve body (1) in¬ dependent from the positions of the entrances of cartridge (10). 12 . A mixing valve according to claim 1, characterized in that said hydraulic responsive member (50) includes two * parts (50A,50B) , the first part (50A) having the passages ' (51,52) and housing packings which seal with the inlets of the body, and the second part (50B) being mount¬ ed with seals acting towards the bore of body (1) and the first part (50A) and having a passage (56) therethrough. 13 . A mixing valve according to claim 12, characterized in that said second part (50B) of the hydraulic responsive member (50) is formed by a body of elastomeric material also forming the seals (figure 3). 14 . A mixing valve according to claim 1, characterized in that the passages (51,52) of said hydraulic responsive member (50) open on its skirt surface at different axial levels and are fluidly separated by a seal (61) extending about the perimeter of said hydraulic responsive member (figure 4). 15 . A mixing valve according to claim 1, characterized in that the hydraulic responsive member (10) has two projections (11,12) sealingly inserted in corresponding seatings of the valve body (1), communicating with the water inlets (7,8), and that the total active surface of said projections (11,12), which undergoes a hydraulic pressure directed to¬ wards the cartridge, is greater than the total active surface of the hy- draulic responsive parts (including the fixed plaque 18) which undergoes a hydraulic pressure acting in the opposite direction. 16 . A mixing valve according to claim 15, characterized in that said hydraulic responsive member is formed by the bottom of the cartrid¬ ge (10).

Inventors: KNAPP ALFONS, KNAPP, ALFONS
Applicants: GEVIPI AG, GEVIPI A.G.
Application year: 1985
Main classification: F16K11
IPC codes: F16K11