WO2011067628A2

WO2011067628A2 - Water mixing system with water saving function

Info

Publication number: WO2011067628A2
Application number: PCT/IB2009/055545
Authority: WO
Inventors: Vítor António FERREIRA DA COSTA
Original assignee: Universidade De Aveiro
Priority date: 2009-12-02
Filing date: 2009-12-07
Publication date: 2011-06-09
Also published as: WO2011067628A3; PT104854A

Abstract

The present invention refers to a mixing system associated to an accumulation system which allows water savings in domestic water installations. When hot water is required at the valve exit (13), but no hot water is available at the valve inlet (11), the cold or partially water entering the mixing valve through the hot water entry (11) of the mixing valve goes to the accumulation reservoir (14), where it remains stored under pressure, until the hot water reaches the inlet (11) of the mixing valve or the accumulation reservoir (14) is filled with water. Only when hot water exists at the inlet (11) of the mixing valve, or when the accumulation reservoir (14) is charged with water, the water entering the valve through inlet (11) is conducted towards the mixing valve discharge (13). While water exists inside the accumulation reservoir (14), this is conducted towards the cold water inlet (12) of the mixing valve preferably to the cold water (19) coming from the main cold water distribution system, thus allowing potable water savings. Present invention applies in the construction industry, and more precisely in domestic water installation systems.

Description

Title of Invention: WATER MIXING SYSTEM WITH WATER

SAVING FUNCTION

Technical domain of the invention

[1] The present invention refers to a water mixing system consisting of a mixing valve associated to an accumulation system, which allows water savings in domestic installations. The present invention is preferably used by civil construction industry, and more precisely in domestic water installation systems.

Summary of the invention

[2] Usual mixing valves for domestic use promote mixing of two water currents, one of hot water and the other of cold water, in order to allow the existence, at the outlet of the mixing valve, of a mixed water current at a temperature that meets the needs of the user. The exit water temperature is between the temperatures of the inlet currents of cold and hot water entering the mixing valve. The usual mixing valves for domestic use promote, however, potable water loss. In fact, when the user wants hot or partially hot water at the outlet of the mixing valve, but no hot water exists at the valve inlet, the cold or partially cold water at the outlet of the mixing valve does not meet the temperature needs of the user, and it is usually potable water that is directly discharged into the sewage system.

[3] The reason behind the non-existence of hot water at the mixing valve inlet is associated with the volume of the duct linking the hot water source to the mixing valve. A period of time exists between the hot or partially hot water demand at the valve exit, and the hot water existence at the inlet of the mixing valve.

[4] The absence of hot water at the valve inlet, which is relevant for the herein proposed system, occurs when a hot water demand exists after a period during which no hot water demands existed. This corresponds, therefore, to the situation when the hot water distribution duct is initially filled with cold or partially cold water. During the referred waiting time, the cold or partially cold potable water that leaves the mixing valve does not meet the user temperature needs, and it is usually directly discharged into the sewage system.

[5] An opportunity exists for alternative systems to the usual mixing valves, considering water saving devices, and allowing the use, as potable water, of the cold or partially cold water that, during a given period of time, enters the mixing valve through the hot water inlet, which is usually directly discharged into the sewage system. Such alternative system should be applicable to common domestic installations, and they should not have significant operation differences when compared with the traditional systems, as well as significant differences in what concerns the installations that incorporate them.

Background of the invention

[6] Up to present time some systems have been proposed to allow water savings in

domestic installations, the most relevant, accordingly to the present invention, being (by chronological order):

US4750472 refers to a system based on a hot water closed circuit, a driven pump forcing the hot water circulation into the hot water distribution system, in order to guarantee the existence of hot water at the inlet (or nearly at the inlet) of the devices receiving hot water. This is a system trying to partially solve the same problem as that to be solved with the present invention, but the two systems are very different, as the system proposed in US4750472 uses a pump driven by an electric motor to force the water to return to an accumulation reservoir under pressure. On the contrary, the present invention is a purely mechanical system, without use of any type of pump, and has thus the advantage of no need of any additional electrical system and the associated electric consumption.

[7] US4922943 refers to a system to the return and accumulation of the water leaving the domestic or industrial mixing valves, using the short time periods during which the exit water is not being used (such as, for example, in domestic applications, soaping and rubbing, in order not to have to adjust the flow and the exit temperature for a new use after the a short period during which the exit water was not used. Each hot water device using hot water incorporates an additional valve with two stable positions, through which it is selected whether the device should operate normally or if it should operate with the function of return and hot water saving. It is a system whose main objective is to save the water corresponding to the time periods of flow and temperature adjustment to the user needs, which is markedly different from the herein proposed system. With the system proposed by US4922943, and taking as example the usual bath operation, only at the beginning of the bath are the flow and temperature adjusted to the user needs, and during the bath phases that do not require water the water leaving the valve is conducted to an accumulation system. The normal operation of the valve, water exit to the bath operations or the water accumulation function, are both set by the additional valve associated to the hot water using devices. In this way, water loss associated with the time period for flow and temperature adjustments to the user needs only occur once, at the beginning of the bath operation, and not at the beginning of each of the bath phases requiring hot or partially hot water. System proposed in document US4922943 requires a change on the devices using hot water, in order to include, each of them, an additional valve with two stable positions, and it is needed a high accumulation capacity as it is needed to accumulate not only the water corresponding to the initial adjustment of the system to the user needs, but also the water corresponding to the periods when water flows in the valve but is not used by the user (periods during which the additional valve is commanded in order to direct the water leaving the valve to the accumulation system). The here proposed system does not require any additional device on the equipments using hot water, it does not require the user operation to select when the water must follow for the normal use or to the accumulation system (the operation mode of the here proposed system is automatic, in terms of the hot water inlet temperature in the mixing valve), and the required accumulation capacity is only that corresponding to the water volume contained in the tube linking the hot water source and the mixing valve.

[8] System proposed in US5165456 does accumulation of the cold water during the

waiting time for hot water at the outlet of the used device, from which the water is sent through a mixing valve. However, the system proposed in US5165456 does not consider the integration of the mixing valve and the accumulation system as a whole, while this integration is part of the present invention. Due to that, with the system proposed by US5165456 it is not possible to conduct the water entering the hot water inlet of the mixing valve to the accumulation system or to the outlet of the mixing valve, depending on the temperature of the water entering the valve through the hot water inlet or on the level of charge of the accumulation system, and the water contained in the accumulation system is not used preferably to the cold water coming from the cold water distribution system. Another fundamental difference is that with the system proposed by US5165456 the water that is not lost is not accumulated under pressure, and it is to be used in any other application or use different from that which originates it. With the present invention, the water that is saved is accumulated under pressure and it is later used as water entering the mixing valve, that is, it is to be used by the same application that originates it.

[9] The system proposed in US6098213 accumulates the cold water when waiting for hot water at the inlet of the mixing valve. However, the here proposed system does not consider the integration of the mixing valve and of the accumulation system as a whole, this integration being proposed in the present invention. Once again, also with the system proposed in US6098213 it is not meet the conduction of the water entering the valve through the hot water inlet to the accumulation system or to the outlet of the mixing valve as function of the temperature of the water entering the mixer through the hot water inlet or the charge of the accumulation system, and the water contained in the accumulation system is not to be used preferably to the water coming from the cold water distribution system. Also here a fundamental difference is that with the system proposed in US6098213 the water that is not lost is not accumulated under pressure, and it is to be used in any other application or use different from that which originates it. With the present invention, the water that is saved is accumulated under pressure and it is later used as water entering the mixing valve, that is, it is to be used by the same application that originates it. With system proposed in US6098213 water that is saved is to be used in applications/uses that do not require pressurized water, like WC cistern filling.

] System proposed in the (pedido international do sistema inicialmente proposto) has essentially the same operation principles of the here proposed system, which is considered, however, an evolution from the original system considered in that document. However, the here proposed system only requires two external hydraulic connections of the mixing valve, as it is also the case for the common mixing valves, and the mixing valve of the previous system proposed in the referred documents requires more than only the referred two external hydraulic connections. In order to allow only two external connections of the mixing valve, it is necessary that the selection system of the cold water entering the mixing valve be considerably different from the cold water selector of the system previously considered in the above referred documents, and in this case the cold water selector system is mainly a pressure regulation, or pressure reduction, valve, which only permits that cold water from the cold water distribution system enters the mixing valve if the water pressure in the accumulation system decreases below a pre-established value. The here proposed system has the advantage that the mixing valve only needs two external hydraulic connections, as it is the case for the common mixing valves.

General Description of the Invention

] The present invention concerns a water mixing system composed by a mixing valve and an accumulation system, in order to allow water savings in domestic installations. The proposed system, accordingly to the present invention, has characteristics that give it the water saving function, namely a water mixing valve and a water accumulation system. The proposed mixing valve has changes when compared with the usual mixing valves, in order to be integrated into the integrated system with the water saving function. The proposed system presents considerable changes in relation to its previous version (International Application of the system initially disclosed ), with the objective of requiring only two external hydraulic connections, similarly with the usual mixing valves.

] The present system comprises:

a) A mixing valve, which includes the dilatable bulb (2) assembled over a perforated disk (1), the bulb being attached to rod (3) that joins the perforated sliding piston (4), which is linked through rod (6) to piston (7) which is pushed from the right to the left by the spring (5), two levers setting the hot water (9) and cold water (10) inlets, and a check valve (8); and b) A water accumulation device which includes the accumulation reservoir (14), spring (15), and pistons (16) and (17) linked through the rod (18).

When opening the hot water inlet (9) of the mixing valve, but there is no hot water at inlet (11) of the mixing valve, the cold or partially cold water entering the valve through the hot water inlet (11) is conducted to the accumulation reservoir (14), where it remains stored under pressure. Only when hot water exists at the inlet (11) of the valve, or when the accumulation system is fully charged with water, the water entering the valve through the hot water inlet (11) is conducted directly to the discharge (13) of the mixing valve. Water retained in the accumulation reservoir (14) is conducted to enter the mixing valve through the cold water inlet (12), as it was fresh water coming from the cold water distribution system. The accumulation system is such that it gives preference to the use of the accumulated water in reservoir (14), that is, while water exists in the accumulation reservoir (14) it is conducted to the cold water inlet (12) of the mixing valve preferably to the cold water coming from the cold water distribution system (19).

[13] The system is operated by the user as a normal mixing valve through the operation over two levers that set the flow rates of hot (11) and cold (12) water inlets, represented in Figures 1 and 2, but that results in a single duct in Figure 3.

[14] During the period of time when hot or partially hot water is expected at the valve exit

(13) , but no hot water exists at the hot water inlet (11) and the accumulation reservoir

(14) is not fully charged with water, the cold or partially cold water that enters the valve through the hot water inlet (11) is conducted to the accumulation reservoir (14), and during this period of time there is no water discharge at outlet (13) of the mixing valve. Absence of hot water at the hot water inlet (11) is due to the volume of the duct linking the hot water source to the mixing valve, as a time delay exists between the hot water demand at the mixing valve and the existence of hot water at the inlet (11) of the mixing valve. Capacity of the accumulation reservoir (14) is dictated mainly by the conjugation of two factors: the volume of water that one wants to save, and the volume of the duct linking the hot water source and the mixing valve.

Description of the Drawings

[15] Figure 1 - Schematic representation of the proposed mixing valve, the numbers

referring to:

1- Perforated and fixed disk;

2- Dilatable bulb;

3- Rod;

4- Perforated piston;

5- Spring; 7- Piston;

8- Check valve;

9- Hot water closure/inlet;

10- Cold water closure/inlet;

11- Hot water inlet in the mixing valve;

12- Cold water inlet in the mixing valve, or exit of cold water from the mixing valve towards the accumulation system;

13- Mixed water outlet from the mixing valve for use.

[16] Figure 2 - Schematic representation of the accumulation system that works together with the proposed mixing valve, where the numbers refer to:

14- Accumulation reservoir;

15- Spring;

16- Piston;

17- Piston;

18- Rod;

19- Cold water inlet, from the cold water distribution system

[17] The mixing valve and the accumulation system work together, as illustrated by

Figure 3.

[18] Figure 3 - Schematic representation of the integrated system with the wanted potable water saving function, composed by the mixing valve and by the accumulation system. Reference numbers in Figure 3 refer to the same elements as indicated before, in Figures 1 and 2, and they are thus addressed through the same reference numbers.

[19] The accumulation system in Figure 2 can reside in the most adequate place, but it should be as close as possible of the mixing valve schematically presented in Figure 1. Outlet (12) of the accumulation system of Figure 2 is linked to the inlet (12) of the mixing valve. Also, there is only a hydraulic connection between the accumulation system and the cold water inlet (12) in the mixing valve.

[20] The proposed system does not present additional difficulties in what concerns its installation as it only requires two external hydraulic connections, as it is also the case for the common mixing valves. The complete system is presented in Figure 3, the two hydraulic connections (inlets) of the mixing valve being the hot water inlet (11) and the cold water inlet (12). However, in this case the cold water inlet (12) comes from the accumulation system, conjugated with the cold water selection system, the cold fresh water coming from the main cold water distribution system through inlet (19).

Detailed Description of the Invention

[21] The temperature sensor element, which evaluates the temperature of the water at the hot water inlet (11) of the mixing valve, is the dilatable bulb (2) in Figure 1, whose volume increase is converted into a horizontal linear deformation (length increase), taking Figure 1 as reference.

[22] When both inlets (11,12) of the mixing valve are totally closed (9, 10), such that it is guaranteed the closure of the hot water inlet (9) and of the cold water inlet (10), there are no water currents entering the valve and consequently there is no outlet water current (13) leaving it.

[23] Using Figure 1 as reference, if hot water inlet (9) is total or partially opened, thus allowing inlet hot water thorough inlet (11), but the entering water is not hot water, water flows through the holes of fixed disk (1), and as it is cold or partially cold the bulb (2) does not increase its dimension, that is related with piston (4) through rod (3), piston (4) being pushed to the left by the action of spring (5), and piston (4) closes the eventual opening allowing the exit of water entering through inlet (11) towards outlet

(13) of the mixing valve, which is the main water exit of the mixing valve.

[24] Using Figure 1 as reference, the hot water current (11) that cannot flow towards outlet (13) of the mixing valve, flows through the holes of piston (4), through the check valve (8) towards the accumulation reservoir (14). As the accumulation reservoir

(14) receives water pressure inside it increases, thus also increasing the pressure at which water current (12) leaves the mixing valve. This pressure acts over piston (7), and the set formed by pistons (4) and (7) and rod (6) is forced to move to the right, and piston (4) reaches a position such that it allows the exit of water current (11) towards outlet (13) of the mixing valve. If the cold water inlet (10) is opened when the hot water inlet (9) is open, the cold water is directed towards outlet (13) of the mixing valve no matter the temperature of the water entering the mixing valve through the hot water inlet (11), and the amount of water in the accumulation reservoir (14). If both currents of hot (11) and cold (12) water enter the mixing valve, and at the inlet (11) there is no hot water, bulb (2) does not increase its length and, by action o spring (5) piston (4) is forced to the left and does not allow the water current (11) to flow towards outlet (13) of the mixing valve, and it is directed to the accumulation reservoir (14) if it is not fully charged with water, and cold water current (12) is directed towards outlet

(13) of the mixing valve. If both currents of hot (11) and cold (12) water enter the mixing valve, and at the inlet (11) there is no hot water, but accumulation reservoir

(14) is fully charged with water, pressure of current (11) that cannot reach exit (13) increases, and this pressure acts over piston (7) forcing the set formed by pistons (4) and (7) and rod (4) to move to the right, piston (4) reaches a position that allows the exit of the water current (11) towards outlet (13) of the mixing valve, and the cold water current (12) is also directed to outlet (13) of the mixing valve. Using Figure 1 as reference, if both currents of hot (11) and cold (12) water enter the mixing valve, and at the inlet (11) hot water exists, bulb (2) does increase its length and, by action of rod (3) that reaches piston (4), this is forced to move to the right, and allows the water current (11) to flow to outlet (13) of the mixing valve, and cold water current (12) is directed towards outlet (13) of the mixing valve. This is the situation corresponding to the normal operation of the mixing valve.

[25] The cold water current (12) entering the mixing valve is always directed towards outlet (13) of the mixing valve and the water saving function of the system is related with the saving of the water entering the mixing valve through the hot water inlet (11) only, when it is not hot but only cold or partially hot. The cold water current (12) entering the mixing valve comes from the accumulation system presented in Figure 2 preferably to the cold water coming from the main cold water distribution system.

[26] If the accumulation reservoir (14) in Figure 2 is not charged, by action of spring (15) the set formed by pistons (16) and (17) and by rod (18) moves to the right, and allows passage of water from the main cold water distribution system (19) towards the inlet of the cold water (12) of the mixing valve. If the accumulation reservoir (14) is charged with water, the set formed by pistons (16) and (17) and by rod (18) moves to the left under the action of the pressure in the accumulation reservoir (14), against spring (15), thus closing the passage of cold water (19) from the main cold water distribution system directly to the inlet (12) of the mixing valve.

[27] When the accumulation reservoir (14) of Figure 2 is charged, the set formed by

pistons (16) and (17) and by rod (18) of Figure 2 moves to the left under the action of the pressure in the accumulation reservoir (14), against the spring (15) in Figure 2, and closes the passage of the cold water (19) coming from the main cold water distribution system towards the cold water inlet (12) of the mixing valve, but the passage of the water contained in the accumulation reservoir (14) of Figure 2 towards the cold water inlet (12) of the mixing valve is always possible, thus giving rise to a cold water selecting system that preferably uses the water contained into the accumulation reservoir (14) and not the cold water coming from the main cold water distribution system to feed the cold water inlet (12) of the mixing valve.

[28] In what concerns operation, the proposed system is operated in the same way as the common mixing valves, the main difference being that when the water current (11) entering the mixing valve through the hot water inlet is being directed towards the accumulation reservoir (14) there is no water being discharged through the main exit (13) of the mixing valve, thus avoiding water losses that otherwise were discharged into the sewage system.

[29] In what concerns installation, the proposed system is installed in the same way as the common mixing valves, as the mixing valve has only two hydraulic connections to the exterior, as it is also the case for the usual mixing valves.

Claims

Water mixing system for domestic use with water saving function comprising a mixing valve and an accumulation system, wherein the mixing valve has only two inlets (11,12), and has a regulation system that automatically directs cold or partially water that enters the hot water inlet (11) of the mixing valve towards the accumulation reservoir (14), such that preferably during its normal operation, the valve releases through outlet (13) a mixture of hot water that enters through inlet (11) and of cold water that enters through inlet (12), such that the cold water entering inlet (12) comes preferably from the accumulation reservoir (14).

Water mixing system for domestic use according to claim 1, wherein the mixing valve includes a dilatable bulb (2) assembled on a perforated fixed disk (1), the dilatable bulb being linked to a rod (3) that abuts the perforated piston (4), which is linked through rod (6) to piston (7), the later being pushed to the left by action of spring (5), the mixing valve comprising two levers controlling the closure or opening (9,10) of the hot and cold water inlets, respectively, and further comprising a check valve (8). Water mixing system for domestic use according to claim 1, wherein the accumulation system includes a cold or partially cold water accumulation reservoir (14), and a cold water selection system composed by the set formed by pistons (16) and (17), and rod (18) linking them, and by spring (15) that abuts piston (16) pushing it to the right.

Water mixing system for domestic use according to claim 1, wherein the mixing valve receives hot water (11) and supplies mixed water through the outlet (13), and when hot water is absent from the inlet (11) such cold or partially cold water passes through passage (12) towards the accumulation reservoir (14). Water mixing system for domestic use according to the previous claims, wherein the accumulation of water is made in the accumulation reservoir (14) of cold or partially cold water that enters the mixing valve through its hot water inlet (11), the so accumulated water being afterwards used to feed the cold water current entering the mixing valve through inlet (12).

Water mixing system for domestic use according to the previous claims, wherein the water contained in the accumulation reservoir (14) is used instead of the cold water coming from the main cold water distribution system (19) to feed the cold water inlet (12) of the mixing valve, which is accomplished by action of the pressure in the accumulation reservoir (14) acting over the selector set (16, 17, 18), which closes the cold water inlet (19) coming from the main cold water distribution system

Water mixing system with water saving function according to the previous Claims, comprising the following operation phases:

a) when no hot water exists at the hot water inlet (11) of the mixing valve, cold or partially cold water enters the mixing valve through the hot water inlet (11) and since the bulb (2) does not swell, that water is directed towards the accumulation reservoir (14) through outlet (12) of the mixing valve, and enters the accumulation reservoir (14), this process ending when hot water reaches inlet (11) of the valve or when the accumulation reservoir (14) is fully charged with water under pressure;

b) when hot water enters the hot water inlet (11) of the mixing valve, bulb (2) swells, and rod (3) forces the movement of piston (4) to the right, thus allowing the exit of hot water (11) towards the normal exit (13) of the mixing valve;

c) when the accumulation reservoir (14) is charged with water, water entering through the hot water inlet (11) is discharged through the normal exit (13) of the mixing valve, no matter the temperature of the water entering through inlet (11) of the mixing valve.

Water mixing system with water saving function according to claim 5, wherein the levers are used open or close the hot (9) and cold (10) water inlets of the mixing valve, so as to regulate the flow rates of hot or cold water that enter the mixing valve through inlets (11) and (12), respectively, which are mixed and leave the mixing valve through outlet (13) of the mixing valve, making use of the water accumulated into the accumulation reservoir (14) preferably to the cold water coming from the main cold water distribution system (19).

Water mixing system with water saving function for domestic use according to claim 1, wherein the mixing valve only needs two external hydraulic connections, as it is also the case for the conventional mixing valves. [Claim 10] Water mixing system with water saving function for domestic use according to claim 1, wherein water accumulated under pressure in the accumulation reservoir (14) is used, yet at a pressure lower than the inlet pressure of the hot water (11) in the mixing valve, without the need for any additional means (mechanical, electrical or any other) to pressurize the accumulated water.