WO2010103560A1

WO2010103560A1 - Thermostatic system with electronic control for mixing hot and cold water

Info

Publication number: WO2010103560A1
Application number: PCT/IT2010/000105
Authority: WO
Inventors: Giancarlo Tedoldi
Original assignee: Nuova Galatron S.R.L.
Priority date: 2009-03-10
Filing date: 2010-03-10
Publication date: 2010-09-16
Also published as: ITBS20090041A1

Abstract

The invention concerns a thermostatic system with electronic control for the mixing of at least two fluids, in particular hot and cold water. It comprises a first solenoid valve (15) connected at the inlet to a conduit supplying hot water, a second solenoid valve (151) connected at the inlet to a conduit supplying cold water, and a mixing chamber (16) designed to receive in entry the water coming from both the solenoid valves and connectable at exit to at least one utilisation device. Between each of the solenoid valves (15, 15') and the mixing chamber (16) a flow rate sensor (18, 18') and a temperature sensor (19, 19") are provided which are designed to detect, respectively, the flow and temperature of the water flowing out of each of said solenoid valves and to emit corresponding electric signals in feedback towards an electronic control unit (22) configured to control the opening/closing of said valves individually and to vary the ratio of hot and cold mixed water so as to maintain the temperature in exit from the mixing chamber constant.

Description

"THERMOSTATIC SYSTEM WITH ELECTRONIC CONTROL FOR MIXING HOT AND COLD WATER"

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Field of the Invention

This invention relates, in general, to the faucet sector and concerns, in particular, a system _xfor mixing hot and cold water with adjusting the temperature and the rate of flow of the water. State of the Technique

The use of mixing valves as devices for the mixing of at least two fluid substances is by this time well known and widespread.

In particular, in the faucet sector a mixing valve is used to mix two types of water coming from two different water supply systems, typically hot and cold water, and to supply from the outlet, only cold water, or better mixed water at a given temperature, that can be pre-set. These mixing valves can be both the manual type, where the user, by adjusting a control lever can set the temperature and flow as is needed from the outlet, and the thermostat type, in which a thermostatic system arranges to automatically maintain the temperature of the water flowing out to be constant independent of the two hot and cold water flows at the input, by varying the mixing ratios taking into account that the rate of flow of the water can vary according to the change in pressure of the network. Usually, the adjustment of the temperature in this second type of mixing valves is controlled by devices that include a bulb sensitive to the heat which, by expanding and contracting according to the variation in temperature of the fluid flowing through a mixing chamber, varies, by the movement of a regulator, the heat ratios between the flows of the fluids entering and consequently the temperature of the mixed fluid in exit.

There are also some more advanced mixer valve models with which, besides being able to adjust the temperature of the mixed exit water, it is also possible to adjust the rate of flow. The temperature and rate of flow adjustments are carried out manually, by turning knobs and having as a reference some graduated scales inserted on them.

The faucet sector is moving towards, and is however looking for, systems for mixing hot and cold water by which the adjustments can also be controlled at a distance by buttons and possibly viewed on a display and which necessarily must be interfaced with electronic systems and maintaining furthermore and preferably the possibility also of adjusting manually.

And in fact, in this respect thermostatic valves of the so called electronic type have already been proposed, that use as a means of adjustment an auger type of valve operated by a step by step motor where, however, -the latter limits its action at, the command of an obturator in the same way as what happens in manual systems.

For example, in the patent US 5231722, concerning however another application ambit, that of the machine for laundries, the use of two non coincident proportional solenoid valves were proposed for a separate contribution of two fluids with different temperature levels and designed to be mixed in a mixing chamber before their delivery in a mixed form. These solenoid valves are piloted by a controller in answer to signals arriving from a temperature sensor provided in association with the mixing chamber of the two fluids. This proportional solenoid valves system, however, does not appear to have ever been used in the faucet field for sanitary fittings. Furthermore, it is only for a control of the temperature of the already mixed fluid and to provoke a variation in the capacity of the inflowing fluids only on the base of this data, without taking into consideration the reaction times of the solenoid valves so as to intervene and quickly adjust also the capacity/ratios of the inflowing fluids.

Such a system, however, does not appear to be suitable to keep within the most stringent international regulations as regards to the delivery of hot water to sanitary equipment and the like, in the shower systems in particular. These regulations, in fact, foresee answering times and possible drawbacks in very tight water supplies. For example, if there is a lack of cold water or the carrying capacity of this water reduces considerably, the user could get scalded by the delivery of only the hot water, consequently the safety system must respond quickly. Here.- lies the necessity for a. prompt intervention so as to tstop the delivery of water or to reactivate the normal operating conditions. Objectives and Summary of the Invention

The aim of this invention is, on the one hand, to adhere to the present requests of the market as regards to mixing systems of hot and cold water electronically controllable and, on the other hand, to propose a hot and cold water mixing system for faucets able in actual fact to adjust the temperature and carrying capacity of the two types of starting out water, both before and after its mixing, to maintain the temperature of the mixed water delivered stable. Another aim is to propose an electronically controlled automatic system for mixing two fluids, able to instantly respond to the variations in temperature of the two types of hot and cold water also in case of a variation in the capacity or temperature of the fluid being received and also to function in the absence of electric input from the grid. Said aims are reached with a thermostatic mixing system of hot and cold water in the field of faucets according to claim 1 and therefore by taking advantage of temperature and capacity sensors in connection with a microprocessor configured to receive signals coming from said sensors and to control two proportional solenoid valves to control the flows of hot water to be mixed.

Practically the system of the invention is controlled to maintain the temperature of the mixed water delivered stable: both in case the temperature of one or the other of the two flows of water in input varies (due for example, in the case of the hot water, to-Hi the discontinuous turning on of a heating system and- .in the case of cold water, due to the climatic conditions of the ambient), and in case there is a variation in the pressure at input of the one or the other of the two flows of water (due for example to the opening of another faucet in the hydraulic system), to find a point of balance between the two flows of water that correspond in fact to the temperature wanted and set to maintain this temperature over a period of time.

The system of the invention is the source of numerous advantages that can be reassumed at least as follows: easy to install and personalization in relation to its uses; easy to adjust and stabilize over a period of time in the mixing of the two fluids and in the temperature of the mixed fluid delivered; a greater volume of water delivered in less space; less wear in time, as there is no need for components made of materials subject to wear with use, like ceramics, plastic and the like; greater practicality for use for those less able; improved aesthetics; easy to manage with other electronic appliances, such as telephones, remote controls, computers, etc.; and also the possibility of using the thermostatic system both as regards to each individual faucet, and as a "centralized" device at the service of all the sanitary equipment, for example, in the bathroom. Brief description of the Drawings

The invention will moreover be illustrated more in detail in the description thakfollows made- in reference to the indicative aπrcknot limiting drawings enclosed, in which:

Fig. 1 is a generally speaking hydraulic scheme of the mixing system including an electronic thermostatic mixer group;

Fig. 2 is a functional scheme of the thermostatic group in Fig.1 complete with an exit solenoid valve, bistable or not; Fig. 3 Shows a view of a possible several way diverting control valve to be used in combination with the mixer group in Fig. 2; and

Fig. 4 is a view as in Fig. 2, but implemented for the delivery of mixed water to several uses. Detailed Description of the Invention

According to the hydraulic drawing in Fig. 1 , the mixing system proposed here comprises an electronic thermostatic group 11 with an input 12 connected to a hot water delivery pipe, an input 13 connected to a cold water delivery pipe and an outlet 14 for hot, cold or mixed water towards at least one application at a required temperature and delivery capacity.

As shown in Figs. 1 and 2, the electronic thermostatic group 11 basically comprises two proportional solenoid valves, respectively 15, 15', connected, in the input, to the inputs of the hot water 12 and the cold water 13 and, in exit, to a mixer chamber 16 in communication in turn with a possible means of control of the delivery of the mixed water towards one or more applications. Between each of the solenoid valves 15, 15' and the mixer chamber 16 are provided a flowmeter 18, 18' and a temperature sensor 19, 19' designed to detect, respectively, the flowcapacity and temperature of the.water in exit from said solenoid valves and to emit corresponding electric signals. Also at the outlet of the mixing chamber 16 are provided a flowmeter 20 and a temperature sensor 21 designed to detect the capacity and temperature of the mixed water and to send corresponding signals towards an electronic management unit 22. Furthermore, always downstream of the mixing chamber 16, a safety solenoid valve 115 can be provided for closing the system in case of an emergency, for example should there be faults in the proportional solenoid valves.

This management unit 22 includes an electronic control board with conversion systems A/D and a microprocessor that controls the opening and closing, partial or total of the solenoid valves 15, 15', individually, in answer to the capacity and temperature signals sent by the flowmeters and by the temperature sensors each associated with the solenoid valves and at the exit of the mixer chamber. These units will also have means, - such as buttons and a possible display, nor shown - so as to be able to set up and present the capacity and temperature levels of the required mixed water.

In this way, at each variation in the capacity of the hot or cold water at the outlet of every solenoid valve originating from any cause, the management unit 22, that is to say the microprocessor, quickly intervenes in answer to the signals sent by the flowmeters, correspondingly adjusting the opening/closing of one and/or the other solenoid valve so as to reset and maintain the capacity and temperature parameters of the delivered mixed water constant, by adjusting the mixer ratios of the two flows of water. _^ . -. •, - , -.*.

Similarly, and with the same objective, the management unit will intervene to adjust opening/closing of the solenoid valves also in answer to the temperature signals coming from each temperature sensor. The system can be integrated in a single body to facilitate the installation in use and given its position in the shower, bathrooms or the like, it will have to be prepared to function at a low tension, 9-12 Volt, and be provided with a buffer battery 23, which, should there be a drop in the network feed, it will however provide autonomous operating, keeping the proportional solenoid valves open at least for a sufficient length of time to complete a shower for example.

As regards to a possible delivery control means of the water exiting from the electronic thermostatic group 11 towards the applications, which could be a shower head, possible lateral hand showers, massage jets, etc, provided in a shower cabin, it could be made up of a solenoid valve 17 bistable or not as shown in Fig. 2, or of a flow deviator 17' -Fig. 3. This, for example, may have a central hole, 24 to receive mixed water editing from the thermostatic group and lateral delivery holes 25 of the water and other uses by means of an internal deviator - not shown - controlled by a knob 26 and configured to put the central hole from time to time in communication selectively with each of the holes.

As an alternative, a same electronic thermostatic group 11 can be adopted to deliver the water to different sanitary equipment, such as - a bathroom 27, a shower 28, a washbasin -29, a bidet 30 as shownϊin Fig. 4, connecting to the outlet 14 of the group the same number of solenoid valves on/of 31 that open when required by the user by means of push buttons, when the is sanitary equipment is used.

The system described above was referring to two different capacity and temperature control characteristics of hot and cold water to be delivered also in the form of a mixture, this still means however that it can be used to take advantage of and to control the mixing and delivery of other fluids with other characteristics such as for example, pH, concentrations, colours, etc, making use of sensors 32, 33 from time to time appropriate when connected with a relative solenoid valve 34, as shown in a part of Fig. 4.

Claims

"THERMOSTATIC SYSTEM WITH ELECTRONIC CONTROL FOR MIXING HOT AND COLD WATER" * * * * C L A I M S

1. Thermostatic system with electronic control for the mixing of at least two fluids, in particular hot and cold water, comprising a first solenoid valve (15) connected at inlet to a conduit supplying hot water, a second solenoid valve (15¹) connected at inlet to a conduit supplying cold water, and a mixing chamber (16) designed to receive in entry the water coming from both the solenoid valves and connectable at exit to at least one utilisation device to feed with hot water, cold water or mixed water, characterised in that between each of the solenoid valves (15, 15') and the mixing chamber (16) a flow rate sensor (18, 18') and a temperature sensor (19, 19') are provided which are designed to detect, respectively, the flow and temperature of the water flowing out of each of said solenoid valves and to emit corresponding electric signals in feedback towards an electronic control unit (22) configured to control the opening/closing of said valves individually in response to the signals arriving from said sensors so as to vary the ratio of hot and cold mixed -• water and to maintain the temperature, in. exit from the mixing chamber constant.

2. Thermostatic system according to claim 1 , characterised in that also at the outlet of the mixing chamber are provided a capacity sensor (20) and a temperature sensor (21 ) also connected to the electronic control unit (22).

3. Thermostatic system according to claim 1 or 2, characterised in that said solenoid valves are proportional solenoid valves and each capacity sensor is a flowmeter.

4. Thermostatic system according to any of the previous claims, characterised in that the electronic control unit comprises an electronic control board with A/D conversion systems and a microprocessor that controls partial or total opening and closing of the proportional solenoid valves in response to the flow and temperature signals coming from the sensors upstream of the solenoid valves and mixing chamber, respectively, said unit also comprising means for memorising and visualising the capacity and temperature values to be set.

5. Thermostatic system according to any of the previous claims, characterised in that downstream of the mixing chamber (16) can be provided a safety solenoid valve (115) to interrupt the delivery of water should the proportional solenoid valves breakdown.

6. Thermostatic system according to any of the previous claims characterised by a low tension electric feed source comprising at least one buffer battery.

7. Thermostatic system according to any of the previous claims,;f characterised -in that it is enclosed in a container for. its installation in. use and provided with connecting means to an electric feed source including a buffer battery and means for connecting it to an electric feed source including a buffer battery and means for connecting to the conduits for supplying fluids to be mixed and control means of the distribution of the fluid in exit.

8. Thermostatic system according to any of the previous claims characterised in that the exit of the mixing chamber is connected to at least a means for controlling the distribution of the water to several user devices, said means being made up of a solenoid valve or a flow deviator.

9. Thermostatic system according to any of the claims 1-7, characterised in that the exit of the mixing chamber two or more solenoid valves are connected, which are set up and controllable by hand to selectively deliver the water from said mixing chamber towards as many utilisation devices.