GB2554128A

GB2554128A - Pressure reducer assembly

Info

Publication number: GB2554128A
Application number: GB1710203.9A
Authority: GB
Inventors: Hecking Willi
Original assignee: Hans Sasserath GmbH and Co KG
Current assignee: Hans Sasserath GmbH and Co KG
Priority date: 2016-08-08
Filing date: 2017-06-27
Publication date: 2018-03-28
Also published as: DE202016104365U1; GB201710203D0

Abstract

The venting fitting is for drinking water heaters with an air cushion for receiving expansion water. The fitting comprises a housing 12 with a water inlet 14 and outlet 32, whereby in use water flows from the inlet through the housing to the outlet for tapping. An air inlet 72 is connected to the atmosphere and is separated from the water. A connection channel 68 connects the air inlet to an air outlet 74 and includes two backflow preventers 76,78 arranged in series. An air-filled pressure chamber is formed at least partially between the backflow preventers and exerts a pressure in an opening direction on the air-outlet-side backflow preventer 78 and in a closing direction on the other preventer 76. A moveable lifting element such as a piston 64 actuated by an annular diaphragm 44 limits the pressure chamber and is exposed to inlet pressure in the water inlet at one side and to the outlet pressure in the water outlet on the other side. The element moves when a pressure difference exists between the water inlet and water outlet, the movement causing a volume and pressure change in the pressure chamber to open or close the backflow preventers.

Description

₍₁₂,UK Patent Application „₉₎GB «„,2554128	(13) A 28.03.2018
	(43) Date of A Publication
(21) Application No: 1710203.9 (22) Date of Filing: 27.06.2017 (30) Priority Data: (31) 202016104365 (32) 08.08.2016 (33) DE	(51) INT CL: F24H 1/18 (2006.01) (56) Documents Cited: GB 2543868 A CN 203856692 U KR 20020095885
(71) Applicant(s): Hans Sasserath & Co KG (Incorporated in the Federal Republic of Germany) Muhlenstrasse 62, D-41352 Berlin, Germany	(55) l-ield of Search: INT CL E03B, F16K, F24D, F24H Other: EPODOC, WPI
(72) Inventor(s): Willi Hecking
(74) Agent and/or Address for Service: A.A. Thornton & CO. 10 Old Bailey, London, EC4M 7NG, United Kingdom

Title of the Invention: Pressure reducer assembly Abstract Title: Venting fitting for a drinking water heater

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Fig.1

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Pressure reducer assembly

Background of the invention

The invention relates to a venting fitting for drinking water heaters with an air cushion for receiving expansion water and a drinking water heater with such a venting fitting.

A drinking water heater essentially consists of a closed water-filled container. The container has an inlet which is usually provided at its lower end. Cold drinking water is filled into the container through this inlet. An electric heating coil or a heat exchanger with hot water flowing therethrough will heat the water in the drinking water heater. Hot water is provided at an outlet. If hot water is tapped, fresh drinking water is refilled through the inlet.

Prior Art

If water is heated in the drinking water heater it will expand. The expansion water generated in such a way can be released through a safety valve to a drain. The water is then lost. It is, therefore, known to use expansion vessels. The expansion water is received therein and can be returned. It is a disadvantage, however, that expansion vessels require a lot of volume. Their installation requires time and money and the devices are relatively expensive.

In the internet at www.megaflo.com, for example, the enterprise Heatrae Sadia sells drinking water heaters with the trade mark “Megaflo”, the drinking water heaters having an air cushion. The air cushion is provided in the same volume as the drinking water which shall be heated. A swimming separation plate separates the air cushion from the water. The air cushion enables the expansion of the water without activating the safety valve. The air cushion of this known assembly must be regularly re-filled.

GB 2 431 461 A and GB 2413 623 A describe a drinking water heater with an air cushion without a separating plate for internal expansion. A valve with a venturi jet nozzle is provided in the cold water supply line for re-filling the air cushion. Air is transported together with the water. The jet nozzle provides that air is introduced into the installation and into the air cushion without any control. It is a disadvantage of the assembly that the air comprised in the installation will cause an uneven water flow at the tap. Due to its high oxygen content air is also not desirable in the installation because the oxygen will promote corrosion of the installation.

Disclosure of the invention

It is an object of the invention to provide a venting fitting for drinking water heaters with an air cushion for receiving expansion water, where the air cushion is automatically re-filled. According to the invention this object is achieved with a venting fitting of the above mentioned kind, comprising:

(a) a housing with a water inlet and a water outlet for water from a drinking water heater, adapted to have the water flowing from the inlet through the housing to the outlet for tapping;

(b) an air inlet provided at the housing which is connected to the atmosphere and which is separated from the water;

(c) an air outlet provided at the housing;

(d) a connection channel between air inlet and air outlet having two backflow preventers which are arranged in a series;

(e) an air filled pressure chamber which is formed at least partially between the backflow preventers, the pressure of such air filled pressure chamber exerting a pressure in an opening direction on the air-outlet-side backflow preventer and in a closing direction on the air-inlet-side backflow preventer;

(f) a moveable lifting element limiting the pressure chamber, which is exposed to inlet pressure in the water inlet at one side and to the outlet pressure in the water outlet on the other side and which carries out a compensation movement upon a pressure difference between the inlet- and the outlet pressure which causes a volume- and pressure change in the pressure chamber whereby the backflow preventers open or close.

The assembly according to the present invention provides a flow of the water through a housing.

Each time, when water is tapped, a pressure drop is effected at the water outlet. The outlet pressure decreases. Thereby, a pressure difference between the inlet pressure at the water inlet and the outlet pressure is effected. The pressure difference causes a compensation movement of the lifting element. It is moved in the direction of the water outlet by the increased inlet pressure. The movement of the lifting element simultaneously causes a decrease of the volume in the pressure chamber which is limited by the lifting element. Thereby the air pressure in the pressure chamber is increased. The backflow preventer on the side of the air outlet opens at increased air pressure in the pressure chamber. Simultaneously, the increased air pressure maintains the backflow preventer on the side of the air inlet in a closed position. Air is released through the open backflow preventer from the pressure chamber to the outlet in the container of the drinking water heater. In such a way the air cushion is re-filled with air. If the pressure difference is compensated the lifting element will move back to its idle position. Thereby, the volume in the pressure chamber is increased again. The pressure drops in the pressure chamber. The backflow preventer on the air outlet side closes. The backflow preventer on the air inlet side opens. Thereby, air enters from the atmosphere into the pressure chamber until the pressure conditions are compensated again.

Each time, when water is tapped, air is transferred to the air cushion with the assembly according to the present invention.

Preferably, it is provided that the air inlet is connectable to the inside of the water container of a drinking water heater and is separated from the water. The air will then, contrary to known assemblies, not flow through water-containing flow paths. Accordingly, the water is not enriched by air or oxygen.

The air outlet can end directly in the water or in the air cushion. However, a connection line in the form of a tube or a pipe may also be provided which ends in the water or in the air cushion. The air inlet can end in the atmosphere or also be connected by a connection line in the form of a tube or a pipe to the atmosphere.

The assembly according to the present invention may be located almost at any position along the water pipe before the tap. The venting assembly can be positioned inside the drinking water heater, for example below the water surface or in the air cushion. It is, however, also possible to provide the venting assembly outside the container of the drinking water heater. In this case, a connection line will transfer air from the air outlet into the container. Furthermore, it is possible to arrange the venting assembly not in the range of the hot water pipe, but in the cold water pipe.

It is only important, that a water flow is generated through the housing which causes a pressure difference between the inlet- and the outlet pressure upon tapping.

Preferably, it is provided that the lifting element in the housing separates an inlet chamber with inlet pressure from an outlet chamber with outlet pressure. Then the forces generated by the pressure differences directly act on the lifting element.

In particular, the lifting element may comprise a piston. The piston may be connected to the inner edge of a flexible, annular diaphragm and the outer edge of the flexible, annular diaphragm may be tightly fixed to the inside of the housing. Then, the effective area exposed to the forces caused by the pressure difference is not limited to the piston area. The diaphragm separates the inlet chamber from the outlet chamber, but enables an unaffected movement of the piston. It is also possible to use any other flexible or moveable element instead of a diaphragm.

Preferably, it is provided that the piston and/or annular diaphragm is provided with openings connecting the inlet chamber to the outlet chamber. The water flow from the inlet chamber to the outlet chamber is led though such openings. A pressure compensation is effected also through such openings upon tapping.

In a further modification of the invention it is provided that the opening in the piston is provided with a backflow preventer opening in the direction of the outlet chamber. The backflow preventer forms a resistance for the flow. Only after a sufficient pressure difference has built up,

i.e. sufficient water is tapped, the backflow preventer will open.

Preferably, the annular diaphragm is provided with openings having an overall opening cross section which is smaller than the opening cross section of the opening in the piston. Small flow volumes may then bypass the backflow preventer by flowing through such small openings in the diaphragm. The tapping volumes are, therefore, not necessarily limited to large amounts. Alternatively, the diaphragm is closed, i.e. without openings and the piston has a bypass opening bypassing the backflow preventer cartridge. As long as the bypass opening has the identical cross section as the openings in the diaphragm operability will remain the same.

Preferably, a guiding for guiding the lifting element is provided. The lifting element may be biased by a spring which moves the lifting element to an idle position where the pressure chamber has a maximum volume. The lifting element must not be moved back to its initial position either at random or by hand - as it is the case with the pump for bicycles. The spring automatically pushes the lifting element back into its initial position after tapping. The volume in the pressure chamber is increased during the return-movement whereby a pressure drop is generated. This causes the backflow preventer on the air inlet side to open. Air enters through the air inlet into the pressure chamber. The spring power is selected in such a way that the resistance of the backflow preventer on the air inlet side between the air inlet and the air outlet can be overcome.

The object of the present invention is achieved in particular with a drinking water heater with an air cushion for receiving expansion water comprising a venting fitting of the above mentioned kind. Apart from such a venting fitting a drinking water heater comprises also a heatable, closed container for the water to be heated; an inlet for re-filling drinking water; and an outlet passage for hot water which starts below the water surface in the water and which is provided with an air cushion in the container above the water surface for receiving expansion water.

Further modifications of the invention are subject matter of the subclaims. An embodiment is described below in greater detail with reference to the accompanying drawings.

Definitions

In this description and in the accompanying claims all terms have the meaning well known to the person skilled in the art which is defined in technical literature, norms such as DIN EN 8011 and DIN EN 1717 and the relevant internet sites and publications, in particular of the lexical kind, such as www.wikipedia.de,www.wissen.de or www.techniklexikon.net, of competitors, research institutes, universities and associations, such as, for example, Deutscher Verein des Gas- und Wasserfaches e.V. or Verein Deutscher Ingenieure. In particular, the terms used here have not the opposite meaning of what the person skilled in the art will derive from the above publications.

Furthermore, the following meanings are the basis for the used terms:

fitting	is a component for the installation in or at a pipe, conduit or tubing or any other fluid installation for blocking, controlling or influencing of mass flows.
outlet	A fitting may be designed as one portion only or with a plurality of portions and is installed at one point in or at the pipe, conduit or tubing. Fittings are, for example and not exclusively: connection devices, connection fittings, main service valves, service fittings, throttle fittings, taps, tap installations, drain fittings, safety fittings, backflow protection devices, adjusting fittings. is an outlet side opening in a housing where a mass flow can flow out. In
axial	particular, the opening may be connected to a pipe or another fitting or freely open towards the atmosphere. is the direction of the rotational axis of components which are entirely or
bore hole	partially rotationally symmetric, such as pipes, tubes or elongated housings. In components without rotationally symmetry it designates the main flow direction in a section of the component. is any kind of connection between two cavities and blind holes.
passage inlet	is a connection enabling mass flows. is an upstream opening in a housing where a mass flow can flow into. In
housing	particular, the opening may be connected to a pipe or another fitting or open freely towards the atmosphere. limitation for matter, components, instruments and measuring devices towards the outside. A housing can be one portion or be constituted of a plurality of connected portions and may be constituted of one or more materials.
nut	machine element for establishing releasable connections. The nut is a hollow
Pipe	body with an inner thread. hollow body comprised of cylindrical sections. It usually serves as a pipe line.

backflow preventer safety fitting to prevent backflow. A device which is designated to prevent

	the backflow of a fluid flow in a direction opposite to a designated flow direction.
shoulder	transition between section having different diameters or thicknesses.
socket	rim or transition portion at an opening.
valve	component for blocking or controlling a fluid flow.

tap (=tap point) is the point where either water or drinking water is directly tapped by a user or tapped by a connected apparatus

Brief description of the drawings

Fig.1 is a cross section of a venting fitting for drinking water heaters, when a small amount of water is tapped along a cross sectional plane A-A.

Fig.2 is a cross section of the venting fitting of Figure 1, along a cross sectional plane CC which is rotated by an angle of 90 degrees.

Fig. 3 is a cross section of the venting fitting of Figure 1 in an idle position, if no water is tapped.

Fig.4 shows a detail of Figure 3, with two backflow preventers between the air inlet and the air outlet where the backflow preventer on the side of the air inlet is open.

Fig.5 is a cross section similar to the one in Figure 2, in the idle position shown in Figure

3, when no water is tapped.

Fig.6 shows a detail of Figure 1 with two backflow preventers between the air inlet and the air outlet where the backflow preventer on the side of the air outlet is open.

Fig.7 corresponds to Figure 1 with larger flow volumes.

Fig. 8 shows a drinking water heater where the venting fitting is positioned in the range of the water surface.

Fig.9 shows a drinking water heater where the venting fitting is positioned outside the water container.

Fig. 10 shows the fresh water line towards a drinking water heater with an integrated venting fitting.

Fig. 11 corresponds to Figure 7 with larger flow volumes along a cross sectional plane C-C which is rotated by an angle of 90 degrees.

Fig. 12 is an exploded view of the assembly of Figure 1.

Fig. 13 corresponds to Figure 8 with a boiler model to scale.

Fig. 14 corresponds to Figure 9 with a boiler model to scale.

Detailed description of the embodiments

Figure 1 shows a venting fitting generally designated with numeral 10. The venting fitting 10 is provided with a housing 12. A water inlet 14 is provided at the lower end of the housing 12. In the present embodiment the water inlet 14 has the form of a threaded socket 20. It is, however, also possible to use an opening or a pipe- or tube-shaped water inlet. The housing 12 has two portions. A lower housing portion 15 has an essentially cylindrical wall 16 and a bottom 18. The threaded socket 20 is integrated with the water inlet 14 at the lower end of the bottom 18. An upper housing portion 22 is screwed into the lower housing portion 15. A thread 24 is provided for this purpose. The upper housing portion 22 also has an essentially cylindrical wall 26. A threaded socket 30 is integrated to the top 28 of the upper housing portion 22. The threaded socket 30 forms a water outlet 32. In the present embodiment the housing portions 15 and 22 and the threaded sockets 20 and 30 are coaxially arranged. An non-coaxial arrangement is, however, also possible.

Six guiding ribs 36 circularly extend from the bottom of the lower housing portion 15. The guiding ribs 36 are elongated and extend in an axial direction into the inside of the lower housing portion 15. A piston generally designated with numeral 38 is moveably guided by the guiding ribs 36.

The piston 38 is provided with elongated guiding members 40 at its lower end. The guiding members 40 are also arranged in a circle and co-operate with the guiding ribs 36 in such a way, that the piston is moveably guided in an axial direction. The circle of guiding members 40 engage in the circle of guiding ribs 36. The guiding ribs 36 and the guiding members 40 each have a length which ensures an overlapping at all times even if the piston 38 is in its upper end position. The upside of the guiding ribs 36 form a lower stop for the piston 38.

A nut 42 is screwed onto the piston 38. The inner edge 46 of an annular diaphragm 44 is fixed to the piston 38 with such nut 42. The annular diaphragm 44 consists of flexible plastic material. The outer edge 48 of the annular diaphragm 44 is clamped between an annular projection 50 which extends towards the inside on the inside of the wall 16 and the underside of the upper housing portion 22. The outer edge 48 of the annular diaphragm 44 is, therefore, tightly fixed to the housing. The inner edge 46 follows the piston movement.

The piston 38 and the annular diaphragm 44 divide the inside of the housing 12 into an inlet chamber 52 and an outlet chamber 54. Inlet pressure is present in the inlet chamber 52 which is connected to the inlet 14. Outlet pressure is present in the outlet chamber 54 which is connected to the outlet. This can be well recognized in Figure 2.

The annular diaphragm 44 has openings 56. The openings 56 have a relatively small diameter. The openings 56 connect the inlet chamber 52 to the outlet chamber 54. Small amounts of water can flow from the inlet 14 through the openings 56 to the outlet 32. This is illustrated by an arrow 58. The openings 56 enable a slow pressure compensation between the inlet chamber 52 and the outlet chamber 54.

The piston 38 is biased by the force of a spring 60. The spring pushes the piston 38 downwards in an idle position. Such idle position is shown in Figure 3. At its upper end the spring is supported at the inside at the top of the upper housing portion 22.

The upside of the piston 38 is tightly connected to an upper piston portion 64 by means of webs 62. The piston portion 64 is cylindrical and moveably guided in a hollow cylinder guiding 66 in an axial direction. The upper rim of the guiding 66 is integrated in the inside of the upside of the upper housing portion 22 and extends downwardly therefrom. An annular O-seal 86 seals the inside of the guiding 66 against the outlet chamber 54. The piston portion 64 follows the movement of the piston 38. The spring 60 is arranged around the guiding 66 and the piston portion 64. The spring 60 has a smaller diameter than the inner edge of the annular diaphragm 44. Thereby, the annular diaphragm 44 moves outside the spring and the upper piston portion 64 between the inlet chamber 52 and the outlet chamber 54.

In the range of the upside 28 of the upper housing portion 22 a connection passage 68 is provided with an essentially tubular housing 70. The connection passage 68 connects an air inlet 72 to an air outlet 74. In the present embodiment the housing 70 of the connection passage extends horizontally lateral through the axis 34. Another shape is, however, also possible. The housing 70 is arranged above the upside 28 but underneath the threaded socket 30 with the outlet 32. The outlet chamber 54 extends sideways around the housing 70 to the outlet 32. This can be well seen in Figure 2. In such a way the outlet chamber 54 is connected to the outlet 32.

In the present embodiment an inlet portion 73 is inserted on the air inlet side into the housing 70. The inlet portion 73 is connected to the housing 70 by means of a bayonet connection. The inlet portion 73 is a bent pipe section in the present embodiment. By suitable design of the inlet portion 73 the venting fitting 10 can be adapted to different environmental conditions. In a similar way an outlet portion 75 is connected to the air outlet side of the housing 70 by means of a bayonet connection.

Two backflow preventers 76 and 78 are provided in the connection passage 68. In the present embodiment the backflow preventers 76 and 78 are coaxially arranged. In an non-linear connection passage 68, however, it is possible to arrange the backflow preventers in a geometrically different consecutive order. The backflow preventers 76 and 78 open in the direction of the air outlet 74. An air filled cavity 80 is present between the backflow preventers 76 and 78.

A bore hole 82 is provided on the upside 28 of the upper housing portion 22. The bore hole 82 extends to the upper end of the cavity 80. The lower end of the bore hole 82 ends in the inside of the cylindrical guiding 66. Consequently, the bore hole 82 connects the inside 84 of the cylindrical guiding 66 to the cavity 80. The cavity 80, the bore hole 82 and the inside 84 of the cylindrical guiding form an air-filled pressure chamber. The upper piston portion 64 follows the movement of the piston 38 in an axial direction. Thereby, the volume of the air-filled portion of the inside 84 of the cylindrical guiding 66 changes. The upper piston portion 64 is provided with an annular seal in the form of an O-ring 86. Thereby, the inside 84 of the cylindrical guiding 66 is sealed against the outlet chamber 54. The cylindrical guiding 66 is long enough in an axial direction to ensure that the annular sealing 86 remains in the guiding 66 even in the lowest piston position of the piston 38.

The piston 38 is provided with a center bore hole 88. A backflow preventer 90 sits in such center bore hole 88. A shoulder 92 on one side and a securing ring 91 secure the position of the backflow preventer 90. The backflow preventer 90 opens in an upward direction in the representation in the direction of the outlet chamber 54.

The described assembly operates as follows:

Figure 3 and Figure 5 show the assembly in a position where no water is tapped and no water flows. In this position the spring 60 pushes the piston 38 in a lower end position. In this position the underside of the piston 38 pushes against the upside of the ribs 36. The upside of the ribs 36 form a lower stop.

If a small amount of water is tapped water flows in the direction of the arrow 96. The water flows from the inlet 14 in the direction of the arrow 98. This can be seen in Figures 1 to 3. It flows in the direction of the arrow 94 through the inlet chamber 52 to the openings 56 in the diaphragm 44. Small amounts of water flow through the openings 56 in the diaphragm into the outlet chamber 54. This illustrated by an arrow 58. Water flows from the outlet chamber 54 to the outlet 32. The water passes the housing 70 of the connection passage 68. This is illustrated by arrows 100 in Figure 2. If small amounts of water are tapped the cross section of the openings 56 in the diaphragm is sufficient to achieve a slow pressure compensation. If larger amounts of water are tapped the cross section of the openings 56 is not sufficient anymore for a quick pressure compensation. A pressure drop is generated between the outlet chamber 54 and the inlet chamber 52. The pressure in the outlet chamber 54 is smaller. Due to the pressure difference the diaphragm 44 and thereby the piston also are moved upwards in the representation in the direction of the outlet chamber 54. This situation is shown in Figures 1 to

3. The upper piston portion 64 is moved upwards together with the piston 38. Thereby, the volume in the pressure chamber comprising cavity 80, bore hole 82 and the inside 84 of the cylindrical guiding 66 is reduced. Accordingly, the pressure in the pressure chamber is increased.

The increased air pressure in the pressure chamber 80, 82, 84 acts on the backflow preventer 76 on the side of the air inlet in a closing direction. This backflow preventer 76 remains closed. The increased air pressure in the pressure chamber 80, 82, 84 acts on the backflow preventer 78 on the side of the air outlet in an opening direction. This situation is shown in Figure 6. The air is, therefore, pressed from the pressure chamber through the backflow preventer 78 in the direction of the air outlet 74 until the pressure conditions are again compensated. It does not matter, how long the tapping procedure takes. It is only important, that water is tapped for at least a short period of time, causing a pressure difference with a piston movement of the piston 38.

With the time a pressure compensation is effected between the inlet chamber 52 and the outlet chamber 54 through the openings 56. The spring 60 pushes the piston 38 back down in the representation to its initial position. Thereby, the volume in the pressure chamber 80, 82 and 84 is increased again. The increase of the volume causes a pressure drop of the air pressure in the pressure chamber 80, 82, 84. The low pressure thus generated causes the backflow preventer 78 on the side of the air outlet 74 to close. Simultaneously, the backflow preventer 76 on the side of the air inlet 72 will open. The air inlet 72 is connected to the atmosphere. Accordingly, the air can re-fill through the connection passage 68 from the air inlet 72 through the backflow preventer 76 into the pressure chamber 80, 82, 84.

The bore 88 in the piston 38 forms another connection between the outlet chamber 54 and the inlet chamber 52. If larger amounts of water are tapped the water not only flows through the small openings 56 in the diaphragm. Due to the pressure difference between the inlet chamber 52 and the outlet chamber 54 the backflow preventer 90 in the bore hole 88 will open also. Larger amounts of water flows through the backflow preventer 90 into the outlet chamber 54 (Figure 11).

The assembly causes the water flow to influence the pressure conditions with each tapping procedure in such a way that air is pressed from the pressure chamber to the air outlet 74. At the end of the tapping procedure the outlet pressure builds up again and air is sucked in from the air inlet 72 into the pressure chamber.

Figures 8 to 10 illustrate how the assembly can be used for re-filling an air cushion in a drinking water heater.

Figure 8 is not to scale and schematically illustrates a first embodiment. The venting fitting 10 is installed in the range of the water surface 102 inside the water container (shown in a minimized form). Water is re-filled through an inlet 106 from a water source, such as, for example, a cold water supply. This is represented by arrow 108. The water inlet 14 of the venting fitting 10 is installed below the water surface 102. The lid of the water container 104 is provided with an opening to the atmosphere and a consecutive pipe socket 109. The pipe socket 109 can be an integrated part or screwed on. The air inlet 72 is inserted into the pipe socket 109 with a thread and sealed. The air outlet 74 ends without any further devices below the water surface. In an alternative embodiment, which is not shown here, the air outlet 74 ends over the water surface 102.

The water outlet 32 extends through an opening in the lid of the water container 104 (a tube section, for example, may serve as a connecting member). An additional, tubular guiding is provided in the present embodiment where the threaded socket 30 is screwed on.

If water is tapped water is re-filled through the inlet 106. The pressure drop at the outlet 32 causes air to be pressed into the water. It moves upwards and re-fdls the air cushion 110. After finishing the tapping procedure air is sucked in through the air inlet 72 from the atmosphere.

The venting fitting 10 can be entirely installed outside the container 112 of the drinking water heater. This is shown in Figure 9. Then the water inlet 14 extends through a tubular connection 116 through the lid of the container 112. The tubular connection 116 ends in the water below the water surface 118. The air inlet 72 does not require any further connection elements, as it is already present in the atmosphere. The air outlet 74 is connected to the inside of the container by a tube or a pipe connection 120. In the present embodiment the pipe connection 120 ends directly in the air cushion 122. The venting fitting 10 is identical in both embodiments shown in Figures 8 and 9.

Figure 10 shows a slightly varied embodiment. There, not the flow of hot water from the water container is used for generating a pressure difference, but the flow of cold water. The fitting 10 is installed inside the pipe line for the cold water supply of the water container. An air outlet is not provided. The air is transferred into the water through a bore hole 124. The bore hole 124 connects the range behind the backflow preventer 78 with water-guiding water outlet 32. The air in this embodiment is transported together with water into the drinking water heater. A Venturieffect, as disclosed with known assemblies, however, is here not used either.

Claims

1. Venting fitting for drinking water heaters with an air cushion for receiving expansion water, comprising:

(c) an air outlet provided at the housing;

2. Venting fitting according to claim 1, characterized in that the air inlet is connectable to the inside of the water container of a drinking water heater and is separated from the water.

3. Venting fitting according to claim 1 or 2, characterized in that the lifting element in the housing separates an inlet chamber with inlet pressure from an outlet chamber with outlet pressure.

4. Venting fitting according to claim 3, characterized in that the lifting element comprises a piston.

5. Venting fitting according to claim 4, characterized in that the piston is connected to the inner edge of a flexible, annular diaphragm and the outer edge of the flexible, annular diaphragm is tightly fixed to the inside of the housing.

6. Venting fitting according to claim 4 or 5, characterized in that the piston and/or annular diaphragm is provided with openings connecting the inlet chamber to the outlet chamber.

7. Venting fitting according to claim 6, characterized in that the opening in the piston is

10 provided with a backflow preventer opening in the direction of the outlet chamber.

8. Venting fitting according to claim 6 or 7, characterized in that the annular diaphragm is provided with openings having an overall opening cross section which is smaller than the opening cross section of the opening in the piston.

9. Venting fitting according to any of the preceding claims, characterized by a guiding for guiding the lifting element.

10. Venting fitting according to any of the preceding claims, characterized in that the lifting

20 element is biased by a spring which moves the lifting element to an idle position where the pressure chamber has a maximum volume.

11. Drinking water heater with an air cushion for receiving expansion water comprising a venting fitting according to any of the preceding claims.

Intellectual

Property

Office

Application No: Claims searched:

GB1710203.9

1-11