Classifications

• • E—FIXED CONSTRUCTIONS
  • E03—WATER SUPPLY; SEWERAGE
  • E03B—INSTALLATIONS OR METHODS FOR OBTAINING, COLLECTING, OR DISTRIBUTING WATER
  • E03B7/00—Water main or service pipe systems
  • E03B7/04—Domestic or like local pipe systems
• • E—FIXED CONSTRUCTIONS
  • E03—WATER SUPPLY; SEWERAGE
  • E03B—INSTALLATIONS OR METHODS FOR OBTAINING, COLLECTING, OR DISTRIBUTING WATER
  • E03B7/00—Water main or service pipe systems
  • E03B7/04—Domestic or like local pipe systems
  • E03B7/045—Domestic or like local pipe systems diverting initially cold water in warm water supply
• • E—FIXED CONSTRUCTIONS
  • E03—WATER SUPPLY; SEWERAGE
  • E03B—INSTALLATIONS OR METHODS FOR OBTAINING, COLLECTING, OR DISTRIBUTING WATER
  • E03B7/00—Water main or service pipe systems
  • E03B7/09—Component parts or accessories
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D17/00—Domestic hot-water supply systems
  • F24D17/0078—Recirculation systems
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D19/00—Details
  • F24D19/10—Arrangement or mounting of control or safety devices
  • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
  • F24D19/1051—Arrangement or mounting of control or safety devices for water heating systems for domestic hot water

Definitions

• the present invention relates to a water tapping point and a tap water network effectively impeding bacterial growth, in particular, legionella bacteria growth, in the water tapping point as well as in the water network.
• the hot water space and the mixing chamber constitute an environment for the growth of water-borne bacteria, especially the feared legionella bacteria that can increase in numbers up to 10,000- fold within 48 hours if the water temperature is about 35° C.
• the legionella bacterium does circulate in water as a free-living organism, and is also a part of a very complex micro-environment that is found, for example, on the inside of water tanks, water pipes and mixers.
• the bio film which there consists of micro-organisms, becomes a thin layer of slime and is surprisingly resistant to influences such as biocides used specifically for the purposes of combating the growth of the bacteria.
• a biocide may effectively kill all free-living bacteria in the water, but the bacteria in the biofilm will often survive and start to multiply in the water as soon as the conditions allow it.
• This capability of "hiding” makes certain bacteria e.g. legionella very difficult to effectively control.
• the problem is increasing, supposedly related to the more widespread use of modern apparatuses having spaces with stagnant water allowed to cool down or warm up to the hazardous temperature region of 25-50° C.
• a typical example of such apparatus and a potential source of legionella bacteria being modern thermostatic mixers. Bacterial growth is considered to cease at temperatures above 50° C.
• a tapping point including a mixer for hot and cold water, with a hot water and a cold water inlet, and a hot water and a cold water space.
• the mixer additionally is provided with a hot water outlet from the hot water space of the mixer. The outlet is connected to a hot water return pipe and through an arrangement of valves the hot water is always kept under circulation. This will assure that the water will not cool down to the hazardous temperature region 25-50° C.
• Thermally insulated return pipes for hot water are, in fact, often already installed in the water mains network of a building, whereby in such cases, the return pipes only need to be furnished with branches off to the respective tapping point. This will keep the installation and maintenance cost at a reasonable level.
• legionella and other bacteria have been considered to be a problem mainly in systems with heated water. Recently attention has been drawn also to the cold water systems. If the cold water is kept immovable for a long period it could heat up to the dangerous temperature region 25-50° C, for example during a hot summer day. Another potential risk is that the cold water system is heated by the hot water system. For example in a common thermostatic mixer the cold water spaces can be heated through thermal conduction from the hot water parts. Similarly warming up through thermal conduction could occur if the hot and cold water pipes are poorly isolated and too close to each other. At temperatures below 18° C legionella growth is known to be very limited. To the best knowledge of the inventor no prior art tapping points are designed to limit the heat transfer between hot and cold parts.
• One object of the present invention is to overcome the drawbacks of the prior art by providing a tap water network that effectively impedes bacterial growth in all parts of the network.
• Another object is to provide providing a tap water network that effectively impede bacterial growth at reasonable installation and maintenance costs.
• a tapping point is provided that allows continuous circulation of hot water in its hot water parts and continuous circulation of cold water in its cold water parts.
• the inventive tapping point gives the possibility to construct a water network with constant circulation of hot and cold water in all parts of the network. Any parts not suitable to circulate with hot or cold water are evacuated and ventilated.
• a realization of the above-mentioned objects, according to one aspect of the invention, is a tapping point comprising a hot water inlet; a cold water inlet, a hot water space; a cold water space, a mixing chamber, a hot water outlet from the hot water space and a cold water outlet from the cold water space, providing a flow of hot return water from the hot water outlet and a flow of cold return water from the cold water outlet.
• the flow of return water from the hot water outlet and the flow of return water from the cold water outlet are combined into a common flow of return water. In doing so circulation of both the hot water and the cold water is achieved without the need of a separate cold water return network.
• the common flow of return water is thus arranged to flow in a common return water
• the water tapping point comprises a hot water inlet; a cold water inlet, a hot water space, a cold water space, a mixing chamber; a hot water outlet from the hot water space and a cold water outlet from the cold water space.
• the hot water outlet from the hot water space and the cold water outlet from the cold water space are combined, by passage means, into a common return water outlet, the latter being adapted for connection to a common return water pipe.
• the hot water outlet and the cold water outlet are provided with adjustment valves to control the flow and temperature of the return water.
• the adjustment valves are typically set once so that the common flow of return water gives a desired flow at a desired temperature which preferably is above 50°C.
• the mixing chamber is provided with a pressure sensitive valve, said valve arranged to open when the tapping point is not in use in order to drain and ventilate the mixing chamber and preferably also any equipment connected to the mixer chamber such as a shower hose, for example.
• FIG. 1 is a front view of a prior art tapping point
• Fig. 2 is a schematic view of the tapping point in Fig. 1 in a closed position
• Fig. 3 is a schematic view of the tapping point in Fig. 1 in an open position
• Fig. 4 is a schematic view of a prior art water supply system
• Fig. 5 a is a schematic view of a water tap point according to one embodiment of the present invention
• Fig. 5b is a schematic view of a alternative embodiment
• Fig. 6 is a partly longitudinal cross sectional view of a water tap point realised in the form of a mixer in accordance with a first embodiment of the invention
• Fig. 7 is a partly longitudinal cross sectional view of a water tap point realised in the form of a mixer in accordance with a second embodiment of the invention
• Fig. 8 is a longitudinal cross sectional view of a water tap point realised in the form of a mixer in accordance with a third embodiment of the invention.
• Fig. 9 is a schematic view of a water supply system in accordance with the present invention.
• the mixer 10 include a mixer housing 12 with a hot water inlet 20, a cold water inlet 40 and a mixer outlet 34 leading to a basin, bath or similar 80.
• the flow and temperature of the water that emerges from the mixer are adjusted by the knobs 14 and 16 respectively.
• the schematic representations in FIG. lb and lc show the principle of the mixer's 10 functional characteristics according to US patent 6,021,803.
• the hot water inlet 20, in connection with a hot water pipe 64 opens into a hot water space 22 that can occupy a larger or a smaller portion of the interior of the mixer housing 12.
• a piping passageway 28 and an inlet valve 30 between the hot water space 22 and a mixing chamber 32.
• the cold water inlet 40 in connection with a cold water pipe 70, opens in an equivalent manner, into a cold water space 42 that can occupy a larger or a smaller portion of the interior of the mixer housing 12.
• a piping passageway 48 and an inlet valve 50 between the cold water space 42 and the mixing chamber 32.
• the inlet valves 30, 50 and the outlet valve 36 are, as indicated in FIG. 2 and 3, mechanically connected to one another so that they can be adjusted when a user turns knob 14 to open the mixer to the position shown in FIG. 3, or to close the mixer to the position shown in FIG. 2.
• the temperature of the mixed water that emerges from the mixing chamber 32 is adjusted with the knob 16 that regulates the mutual opening positions of valves 30 and 50 for setting the desired temperature of the mixed water.
• Knob 16 is additionally connected to a thermostat 46 that is capable of comparing the desired set temperature with the actual temperature via a pipe 44 and that, using feedback via a schematically represented transfer device 47, adjusts the said mutual opening positions in accordance with this desire by what is, in fact, a known mechanism.
• the mixer 12 also has a hot water outlet 24 from the hot water space 22.
• the hot water outlet 24 is arranged to be connected with a return pipe 66 for hot water via an outlet valve 26.
• outlet valve 26 is arranged to be adjusted together with other valves by maneuvering knob 14.
• Outlet valve 26 is open in the closed mixer position (FIG. 2) and closed in the open mixer position (FIG. 3) so as to the hot water space is continuously flushed with hot water when the mixer is not in use.
• a drainage and ventilation outlet 54 extends from the mixer chamber 32. This is opened and closed by a valve 56, which is manoeuvred together with the other valves by turning knob 14. More specifically, valve 56 is arranged so that it is closed during the open mixing position (FIG. 3) and open during the closed mixing position (FIG. 2). If the mixer has two alternative outlets, such as a conventional pipe and a shower hose, both of these can be drained and ventilated via the outlet 54. To further reduce the risk of bacterial growth in the mixer chamber 32, said chamber is preferably constructed with a minimal volume.
• the cold water space 42 can be equipped with a water outlet, preferably through a valve like the hot water outlet valve 26, and connected to a return pipe. Every tapping point will accordingly need to be served with one hot water pipe, one cold water pipe, one hot water return pipe and one cold water return pipe.
• the corresponding tap water system is schematically illustrated in FIG. 4.
• the water mains network comprising of a least one pipe for hot water 450, one hot water return pipe 440, one cold water pipe 420 and one cold water return pipe 430 is branched off, typically at each floor of a building, via pressure controlled regulators 410 and fed to the individual tapping points 400, here illustrated by the above-described thermostatic shower mixers.
• the return cold water is kept cold by a cooling device 460 and the hot water by heating device 470.
• the mixer comprising a mixer housing 500, a hot water inlet 505, a cold water inlet 510 and a mixed water outlet 515 leading to a shower, for example.
• the hot water inlet 505 is connected to a hot water pipe 520 and leads to a hot water space 525.
• the cold water inlet 510 is connected to cold water pipe 530 and cold water space 535.
• the hot water space 525 and cold water space 535 are via valves 540 and 545, respectively, connected to a mixer chamber 550.
• the valves 540 and 545 are operated separately, or are mechanically coupled to each other in a "single -lever" arrangement, and may incorporate thermostatic devices through e.g. arrangements previously described with reference to the prior art mixer of FIG. 2.
• the hot water space is equipped with a hot water outlet 555 and the cold water space with a cold water outlet 560.
• the hot water outlet 555 and the cold water outlet 560 are via adjustment valves 565 and 570, respectively, joined in a common return water outlet 575 and connected to a common return water pipe 580.
• the purpose of adjustment valves 565 and 570 is to set proper flows of the hot and cold return water and hence also the temperature of the return water.
• the adjustment valves 565 and 570 are typically adjusted at installation to give the desired flow and temperature, preferably above 50° C, of the water in the return pipe and are not adjusted during normal operation. This temperature selected to impede bacterial growth as discussed above.
• This temperature selected to impede bacterial growth as discussed above.
• the cold water space 535 and the hot water space 525 are combined into a common inlet water space 527, in which the cold and hot water is mixed prior to, via the valve 585, entering the mixer chamber 550, as seen in FIG 5b.
• the valves 540 and 545 which may include thermostatic devices, are arranged between the respective inlets, 520 and 530, and the common inlet water space 527.
• the common inlet water space 527 is connected to the common return water outlet 575 which in turn is connected to a common return water pipe 580.
• the mixer chamber 550 is not subjected to circulating water when the mixer is not in use. Therefore, to minimize the risk of bacteria growth, the mixer chamber 550 is evacuated through a drainage and ventilation outlet 585 via a valve 590.
• the valve 590 is preferably a pressure sensitive valve arranged to open when the pressure in the mixing chamber falls below a preset value. When both the inlet valves 540 and 545 have been manoeuvred to a closed position, i.e. when the mixer is no longer in use, the pressure will drop in the mixer chamber 550 and the valve 590 will open to drain the mixing chamber. Pressure sensitive valves with suitable characteristics are commercially available. Care has to be taken to also drain and ventilate the parts of the tapping point connected to the mixed water outlet 415. In FIG.
• a shower hose 595 is formed in a spiral shape e.g. with metallic reinforcements and extended by placing the hand shower 597 in a wall support 598 positioned so that the s shower hose spiral will have a continuous downward directed curvature. This arrangement assures that no water will be trapped within the shower hose 595 or the hand shower 597 and all water will drain through drainage and ventilation outlet 585.
• Tapping points can indeed have a more complex construction with a larger plurality of valves, cold and hot water spaces and mixer chambers. Also the size and shape of such spaces can be varied in compliance with the design and/or the intended use of the tapping point.
• the hot and cold water spaces could be comprised in the hot and cold water inlets, for example.
• the skilled in the art will appreciate that also other structures than the above illustrated can utilize the principles of the invention to achieve a circulation of hot and cold water and to drain, with the aid of pressure sensitive valves, any space not suitable for circulation.
• the hot water outlet 555 and the cold water outlet 560, of FIG. 5 are realized by passages 655 and 660, respectively, within the housing of the mixer and are connected to a common return water outlet 675 (corresponding to 575).
• the passages 655 and 660 are provided in the wall of the mixer housing (602).
• Adjustment valves 665 (565) and 670 (570) are provided before the passages connect to the common return water outlet 675, and are made easily adjustable from outside the mixer housing. Shown in the figure are also a hot and cold water inlet, 605 and 610 respectively, and the hot and cold water space, 625 and 635 respectively and a mixing chamber (650).
• FIG. 7 shows another embodiment of the present invention having the junction of the cold and hot water outlet placed outside of the mixer housing.
• the mixer 702 has separate outlets for the return hot water 755 and the return cold water 760.
• the return cold water and the return hot water are then led into an external device, comprising passages for hot and cold water, 704 and 706, respectively, preferably incorporated in a mixer wall support 708 as indicated in FIG. 7, and connected to a common return water outlet 775.
• the wall support can also include the adjustment valves 765 and 770. Shown in the figure are also a hot and cold water inlet, 705 and 710 respectively. As discussed above cold parts of a mixer should be kept cold and hot parts kept hot.
• FIG. 7 shows another embodiment of the present invention having the junction of the cold and hot water outlet placed outside of the mixer housing.
• the mixer 702 has separate outlets for the return hot water 755 and the return cold water 760.
• the return cold water and the return hot water are then led into an external device, comprising passages for
• the shaft 808 is connected to the valve 840 controlling the flow of hot water from the hot water space 825 to the mixer chamber 850.
• the shaft 812 is connected to the valve 845 controlling the flow of cold water from the cold water space 835.
• the valves 840 and 845 are in mutual operation through the shafts 808 and 812 and the handle 814, preferably in a material of low thermal conductivity.
• the knob 816 adjusts the portion of hot water led into the mixer chamber 850. Indicated in the figure are the hot water outlet 855 and the cold water outlet 860 to allow circulation of hot and cold water and the drainage valve 890.
• the thermal transfer between the hot and cold parts of the mixer is reduced.
• the thermal transfer can be further reduced.
• the water mains network can by utilizing the invention, above exemplified with different embodiments, be significantly simplified in comparison with the network of FIG. 4.
• FIG. 9 an exemplary tap water network according to the invention is schematically illustrated.
• the network comprises of a one pipe for hot water 940, one return water pipe 930, one cold water pipe 920 and is branched off, via pressure controlled regulators 910 and fed to the individual tapping points 900.
• the return water pipes are arranged according to the well- known Tishelman coupling principles in order to achieve proper circulation.
• no cold water return pipes are needed and (b) no cooling device 460 is needed.
• the adjustments of all the individual adjustment valves 570 and 565, the regulators in 910 as well as other, in this description omitted, means necessary to control the flow and pressure in a water network is considered to be well-known for the skilled in the art.
• tapping points according to the invention By installing tapping points according to the invention at all tapping points both hot and cold water are kept under constant circulation in the entire water supply network and this irrespective of if the tap points are open or closed. The risk of immovable water heating up or cooling down to the hazardous temperature region is significantly reduced. It should be noted that all tapping points, not only for e.g. shower faucets should be of the kind afforded by the invention in order to maintain the circulation of both hot and cold water in all parts of the water network.
• the invention has been exemplified with embodiments describing water tapping points like shower/bath faucets, but should not be considered limited to such devices. Other applications e.g. dental units would equally well benefit from the invention. Of special importance would be to utilise the invention in equipment rarely used such as emergency showers and emergency eye showers.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mechanical Engineering (AREA)
• Hydrology & Water Resources (AREA)
• Combustion & Propulsion (AREA)
• Public Health (AREA)
• General Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Water Supply & Treatment (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Domestic Plumbing Installations (AREA)
• Devices For Dispensing Beverages (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)
• Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
• Excavating Of Shafts Or Tunnels (AREA)
• Multiple-Way Valves (AREA)

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Citations (5)

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• 2001
  • 2001-07-24 SE SE0102604A patent/SE523144C2/sv not_active IP Right Cessation
• 2002
  • 2002-07-22 EP EP02759016A patent/EP1409902B1/de not_active Expired - Lifetime
  • 2002-07-22 AU AU2002324390A patent/AU2002324390B2/en not_active Expired
  • 2002-07-22 WO PCT/SE2002/001404 patent/WO2003010453A1/en active IP Right Grant
  • 2002-07-22 ES ES02759016T patent/ES2302831T3/es not_active Expired - Lifetime
  • 2002-07-22 JP JP2003515786A patent/JP4253583B2/ja not_active Expired - Fee Related
  • 2002-07-22 CN CNB028187156A patent/CN100430632C/zh not_active Expired - Lifetime
  • 2002-07-22 AT AT02759016T patent/ATE388358T1/de not_active IP Right Cessation
  • 2002-07-22 DE DE60225450T patent/DE60225450T2/de not_active Expired - Lifetime

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