Title of Invention	BACKFLOW PREVENTER.
Abstract	TITLE: BACKFLOW PREVENTER There is disclosed a backflow preventer which is able to be inserted in to a gas or fluid duct and has a closing body which is designed as a hollow body which is open on the discharge side,w hich closeing body delimits between itself and a central closing body counterpart a through-flow passage channel, in which the closure body is able to be moved into an open position through the flow medium flowing in the through-flow direction (arrow 1) through the throughflow passage channel from a closed position, lying in a sealing manner against the closing body counterpart against the restoring force of its inherent elasticity and/or inherent stability, and in which the closing body in its unstressed closed position initially lies obly with a partial regioh, formed as a selaing lip, against a partial or end region of the closing body counterpart and under the load pressure of the fluid flowing back contrary to the through-flow direction, with the releasing of a buffer volume on the discharge side for the backflowing fluid is additinally able to be pressed against the closing body counterpart by a partial region of its longitudianl extent, characterized in that the closing body is held immovably relative to the closing body counterpart in the backflow preventer and the central closing body counterpart is connected with an oncoming flow plate.

Title of Invention

BACKFLOW PREVENTER.

Abstract

TITLE: BACKFLOW PREVENTER There is disclosed a backflow preventer which is able to be inserted in to a gas or fluid duct and has a closing body which is designed as a hollow body which is open on the discharge side,w hich closeing body delimits between itself and a central closing body counterpart a through-flow passage channel, in which the closure body is able to be moved into an open position through the flow medium flowing in the through-flow direction (arrow 1) through the throughflow passage channel from a closed position, lying in a sealing manner against the closing body counterpart against the restoring force of its inherent elasticity and/or inherent stability, and in which the closing body in its unstressed closed position initially lies obly with a partial regioh, formed as a selaing lip, against a partial or end region of the closing body counterpart and under the load pressure of the fluid flowing back contrary to the through-flow direction, with the releasing of a buffer volume on the discharge side for the backflowing fluid is additinally able to be pressed against the closing body counterpart by a partial region of its longitudianl extent, characterized in that the closing body is held immovably relative to the closing body counterpart in the backflow preventer and the central closing body counterpart is connected with an oncoming flow plate.

Full Text	2155686499 WP 2004/090394 PCT/EP2004/003724 Translation of PCT/EP2004/003724 Backflow Preventer The invention relates to a backflow preventer, which can be integrated into a gas or liquid line and which is provided with a closing body, embodied as a hollow body open at the drainage side. The closing body limits a passage channel between itself and a central closing body counterpart, with the closing body being displaceable by the flow medium flowing through the passage channel from a closing position, contacting the closing body counterpart in a sealing manner, into an opening position against the restoring force of its own elasticity and/or own stability. Such backflow preventers arc inserted into sanitary water lines, for example, in order to prevent the backflow of water and in particular the return suction of waste water into the drinking water lines. Such backflow preventers open when the water flows to an outlet. Here, the closing body is displaced by the flow medium, flowing in the flow direction or in the direction towards the outlet, from its closed position into the open position against the restoring force of a return spring. In the event of an undesired backflow, however, the closing body is pressed firmly against the valve seat and kept in its closing position, thus blocking the way back for the return flowing water. The backflow preventers of prior art are usually comparatively complicated and comprise multiple components, thus they are expensive in their production. Therefore, the object of the invention is to provide a backflow preventer characterized in a simple construction, with this simple construction favoring low production costs and operation without malfunction. From CH 572 179 Al a backflow preventer of the type mentioned at the outset is known, which can be inserted into a gas or liquid line. The known backflow preventer is provided with a cone-shaped closing body on its drainage side which is made from an elastic material, limiting a passage channel between itself and a central closing body counterpart. In a closing position the closing body contacts the closing body counterpart 215568 649 9 WP 2004/090394 PCT/EP2004/003724 in a sealing manner, which has a cone-shaped exterior contour and is provided circumference penetrations at its exterior for the fluid flowing through the closing body counterpart. The closing body, which contacts the closing body counterpart and thus closes the penetrations in a tightly sealing manner, is displaced by the fluid flowing through the passage channel in the flow direction against the restoring force of its own elasticity in the opening position. In contrast thereto, the fluid flowing opposite the flow direction is able to additionally press the closing body against the exterior circumference of the closing body counterpart. The use of such backflow valves in the field of one-lever mixing faucets is frequently plagued with the problem that during the closing of the cold water or warm water side, the water, which is enclosed between the closed backflow valve, on the one hand, and the also closed valve seat, on the other hand, is heated to a large extent by exterior influences, until system pressure develops which leads to damages in the weakest part of the supply line and, thus, frequently at the backflow valve. Ultimately, this can lead to a blockage of the supply line or an also undesired cross-flow. Due to the fact that the closing body provided in CH 572 179 A5 is pressed more and more tightly against the exterior circumference of the closing body counterpart by the pressure of the fluid flowing back against the flow direction, undesired high pressure can develop in the backflow preventer known from CH 572 179 A5. Two backflow preventers having a construction to that described in CH 572 179 A5 are known from DE 1 154 982 B and DE 842 567 C, with their use also being subject to the disadvantages and risks described above. Therefore, the object is to particularly provide a backflow preventer of the type mentioned at the outset, having a simple design which promotes low production costs and an operation free from malfunctions, with the backflow preventer also effectively counteracting any excessive increase in interior pressure, 2155686499 WP 2004/090394 PCT/EP2004/003724 In particular, the solution to this objective according to the invention provides in the backflow preventer of the type mentioned at the outset that the closing body, in its unstressed closing position, initially only contacts with a partial area, embodied as a sealing lip, a partial or end region of the closing body counterpart, which narrows in a direction of the flow, and which can be pressed under the stress of the load of fluid flowing back against the flow direction into a buffer volume for the back flowing fluid at the drainage side so that it can additionally be pressed with a partial region of its longitudinal extension against the closing body counterpart. The closing body of the backflow preventer according to the invention is embodied as a hollow body, open on the drainage side, and encompassing a central closing body counterpart. The hollow body initially contacts only with a partial section, embodied as a sealing lip, a partial or end section of the closing body counterpart, still not subjected to any strong backflow. Under the stress of the fluid flowing back opposite the flow direction, the closing body is additionally pressed against the closing body counterpart with a partial section of its longitudinal extension, blocking the return path of the back flowing medium. Here, not only is the sealing surface between the closing body and the closing body counterpart enlarged and the sealing effect effectively increased, also between the exterior of the closing body pressed towards the closing body counterpart, on the one hand, and the encompassing interior wall, on the other hand, a buffer volume on the drainage side is opened for the back flowing fluid, and thus an undesired and potentially damaging increase in interior pressure is compensated. When the fluid flows in the flow direction, though, the closing body is displaced by the flowing medium flowing through the passage channel from its closing position, in which it contacts the closing body counterpart in a sealing manner, into an opening position against the restoring force of its own elasticity and/or own stability. Here the closing body and the closing body counterpart limit a passage channel, in which a gaseous or liquid flow medium flows in the flow direction or outlet direction. Therefore, due to the fact that the closing body is embodied as a hollow body and is made from an inherently elastic material and due to the fact that in the backflow preventer 2155686499 WP 2004/090394 PCT/EP2004/003724 according to the invention a displaceablc valve body made from a hard metal can be omitted, an undesired development of noise is also avoided during the repositioning of the closing body from the open position into its closed position and pressure waves which develop by a fast closing of closing members at the drainage side are dampened. The pressure wave of backflow preventers of prior art, caused by the fast closing of a closing member at the drainage side and recognized as a disturbing noise, is reduced and effectively dampened in the backflow preventer according to the invention by the partial displacement of the buffer volume provided according to the invention. In order for the closing body to be able to execute the high number of opening and closing motions following in rapid sequence it is advantageous for the closing body to be produced from an elastic material. In order for the medium, flowing back at high pressure, not to be able to displace the closing body counterpart beyond the narrowing section, it is advantageous for the sealing lip to be provided, at its free edge region contacting the closing body counterpart, with a reinforcement at the edge which counteracts a widening of the circumference of the edge region. The reinforcement of the edge can be embodied as an annular and non-stretchable material inlay in the closing body edge region, for example. The simple production of the backflow preventers according to the invention is promoted, though, when the edge reinforcement is embodied as a circumferential, cross-sectional expansion or cross- sectional enlargement of the closing body. A preferred embodiment according to the invention provides for the closing body to have a rounded end region and to be embodied preferably in a drop-shaped manner. In this embodiment the high throughput and the little loss in pressure of the backflow preventer according to the invention is favored even more. In order to hold the closing body counterpart in the desired central position inside the closing body, embodied as a hollow body, it is advantageous for the central closing body 2155686499 WP 2004/090394 PCT/EP2004/003724 counterpart to be connected to a through flow plate, provided with flow openings which open into the passage channel. The through flow plate, in the area of the passage channel, is characterized in a flow resistance being as little as possible, when the through flow plate is embodied in the area of the passage channel as a sieve or perforated plate with flow openings embodied preferably honcycomb-shaped. The simple production of the backflow preventer according to the invention is favored even more, when the through flow plate and the closing body counterpart are connected to one another in one piece. An embodiment according to the invention which is produced in a particularly simple and cost-effective manner, provides for the closing body to be held to the exterior circumference of the through flow plate. In order to be able to produce the backflow preventer according to the invention with little expense and from only few components it is advantageous for the closing body with its closing body section held to the through flow plate to contact the interior circumference of the gas or liquid pipeline. In this embodiment a separate annular seal can be omitted. Instead of such an annular seal, the closing body performs the function with its closing body section contacting the interior circumference of the gas or liquid line. In order to enhance such sealing function even further it is advantageous for the edge region of the face of the closing body, contacting upstream the gas or liquid line in a sealing manner, is embodied as a circumferentially extending cross-sectional enlargement. Here, a particularly advantageous further development according to the invention provides for the closing body to be held with its cross-sectional enlargement in a holding groove provided at the exterior circumference of the through flow plate. 2155686499 WP 2004/090394 PCT/EP2004/003724 The reduced production expense is enhanced even further when the backflow preventer is essentially formed in two parts and the closing body, on the one hand, is provided both with a closing body counterpart and, on the other hand, with the through flow plate connected thereto in a single piece. Additional features of the invention are discernible from the following description of an embodiment according to the invention in connection with the claims and the drawing. The individual features can be embodied alone or combined in an embodiment according to the invention. In the drawings: Fig. 1: a backflow preventer, which can be inserted into a gas or liquid pipeline, shown in a cross section, in its original or closed position not subjected to any flow medium Fig. 2: the backflow preventer according to Fig. 1, with the backflow preventer is shown in its closed position on the left of the central axis and in its open position on the right of the central axis, and Fig. 3: a top view of the backflow preventer according to Figs. 1 and 2 on a through flow plate provided upstream. In Figs. 1 through 3 the backflow preventer is shown, which can be inserted into a gas or liquid line, and here it is integrated in a sanitary water line 2. The backflow preventer 1 is provided with a closing body 3 embodied as an essentially pot-shaped hollow body open at the drainage side. As clearly discernible from the closed or normal position of the backflow preventer 1, shown in Fig. 1 unimpinged by the flow medium, the closing body 3 limits a passage channel 5 between itself and a central closing body counterpart 4. 2155686499 WP 2004/090394 PCT/EP2004/003724 In the left half of Fig. 2 it is shown how the closing body 3, made from an elastic or shape-elastic material is additionally defined in the closed position by the back flowing flow medium impinging the closing body 3 on its exterior, causing a large partial section of its longitudinal extension to be pressed against the closing body counterpart 4. Here, the closing body contacts the closing body counterpart 4 under the pressure of the fluid flowing back opposite the flow direction such that between the closing body and the encompassing interior wall of the pipeline a downstream buffer volume is opened for the back flowing fluid. By opening the downstream buffer volume, any undesired increase in interior pressure is compensated, which otherwise might damage the gas or liquid pipeline and/or the functional unit integrated therein. Across therefrom, the backflow preventer 1 is shown in the right half of Fig. 2 in its opening position. Here it is obvious that the dosing body 3 can be displaced by the flow medium flowing in the flow direction Pfl through the passage channel 5 from a closed position, contacting a closing body counterpart 4 in a sealing fashion, into an open position against the restoring force of its own elasticity or its own stability. In Figs. 1 and 2 it is discernible that the closing body counterpart 4 made from a dimensionally stable material, has an end region, which narrows in the flow direction Pfl in a rounded fashion, here. For this purpose, the closing body counterpart 4 is embodied essentially drop-shaped. Here, the closing body counterpart 4 is connected in one piece with the upstream tip of a drop-shaped through flow plate 7, aligned laterally to the flow direction Pfl, which contacts with its edges at least one rest, here embodied as an annular flange 8, in the gas or liquid line 2. It is possible for at least one feeder channel to be penetrated by the closing body counterpart 4, which opens into the passage channel 5. However, here the through flow plate 7 is provided with penetrating openings 9, that open into the passage channel 5. From the top view onto the upstream face of the through flow plate 7, shown in Fig. 3, it is discernible that in the area of the passage channel, said blow plate is embodied as a sieve or perforated plate with preferably honeycomb-shaped penetrating holes 9. 2155686499 WP 2004/090394 PCT/EP2004/003724 The closing body 3 is held to the exterior circumference of the through flow plate 7. Here, the closing body 3 contacts with its closing body section, held to the through flow plate 7, the interior circumference of the gas or liquid pipeline 2 in such a sealing manner that any additional annular seal between the backflow preventer 1 and the gas or liquid pipeline 2 can be omitted. In order to improve the sealing effect of the closing body 3 in this area even more, the edge region of the face of the closing body 3, upstream contacting the gas or liquid line 2 in a sealing manner, is embodied as an annular-shaped encircling cross-sectional enlargement 10. Here, it is discernible in Figs. 1 and 2 that the closing body 2 is held with its cross-sectional enlargement 10 to a mounting groove 11 provided at the exterior circumference of the through flow plate 7. At its downstream partial region, the closing body 3 is embodied as a narrowed and rounded scaling lip 12, which contacts the end region 6 of the closing body counterpart 4. In order for the closing body 3 to additionally be pressed against the closing body counterpart 4, serving as a valve seat, by the flow medium impinging it from the outside and flowing in the opposite flow direction Pf2, and thus also preventing the edge region of the closing body 3, contacting the closing body counterpart 4 with the edge region from being pushed by the high pressure of back flowing medium, over the tapering end section 6 of the closing body counterpart 4, the scaling lip 12 is provided at its free edge region contacting the closing body counterpart 4 with an edge reinforcement 13 counteracting any expansion of the edge region circumference. This edge reinforcement 13 is here embodied as a circumferentially extending cross-sectional expansion or cross- sectional enlargement of the closing body 3. The closing body 3 of the backflow preventer 1 shown here is embodied as a hollow body open at the drainage side, encompassing the central closing body counterpart 4. The closing body 3 and the closing body counterpart 4 define between each other the passage channel 5 through which a gaseous or liquid flow medium flows in the flow direction or towards the outlet Pf 1. Here, the closing body 3 is displaced by the flow medium 2155686499 WP 2004/090394 PCT/EP2004/003724 flowing through the passage channel 5 from the closing position, sealing at the closing body counterpart 4, against the restoring force of its own elasticity and/or own stability into its opening position. However, in the event of backflow of the flow medium in the opposite direction Pf2, the closing body 3, impinged on the outside by the back flowing medium, is held in its closing position, which blocks the backward flow of the back flowing medium. A particular advantage of the backflow preventer 1 shown here is the fact that it can be produced inexpensively and from very few components. The backflow preventer 1 shown here is embodied in two components and essentially comprises, on the one hand, the closing body counterpart 4 connected in one piece to the through flow plate 7 and, on the other hand, the closing body 3. The backflow preventer shown here is characterized in a high flow capacity and a comparatively low pressure loss. 2155686499 Amended Claim 1 under Article 19 1. Backflow preventer (1), which can be inserted into a gas or liquid line (2), comprising a closing body (3) embodied as a hollow body open on a drainage side, which limits a passage channel (5) between the closing body and a central closing body counterpart (4), the closing body (3) being displaceable by a flow medium flowing through the passage channel (5) in a flow direction (Pf 1) from a closed position, contacting the closing body counterpart (4) in a sealing manner, into an open position against a restoring force of an elasticity and/or a stability of the closing body, wherein the closing body (3), in an unstressed closed position, initially contacts only a partial or edge region (6) of the closing body counterpart (4) with a partial region embodied as a sealing lip (12) of the closing body and can additionally be pressed against the closing body counterpart (4) with a partial region of a longitudinal extension thereof under a pressure of the fluid flowing against the flow direction (Pf 1), opening a downstream buffer volume for back flowing fluid, characterized in that the closing body (3) is non-removably held on the backflow preventer in the gas or liquid line. 2. A backflow preventer according to claim 1, characterized in that a free edge region of the sealing lip (12), which contacts the closing body counterpart (4), is provided with an edge reinforcement (13) to compensate against expansion of an edge region circumference. 3. A backflow preventer according to one of claims 1 or 2, characterized in that the edge reinforcement (13) is embodied as an annular cross-sectional expansion or a cross- sectional enlargement of the closing body (3). 4. A backflow preventer according to one of claims 1 through 3, characterized in that the closing body counterpart (4) has a rounded end section (6) and is preferably embodied in a drop shaped manner. 2155686499 WP 2004/090394 PCT/EP2004/003724 5. A backflow preventer according to one of claims 1 through 4, characterized in that the central closing body counterpart (4) is connected to a through flow plate (7), which has penetrating openings (9) which open into the passage channel (5). 6. A backflow preventer according to one of claims 1 through 5, characterized in that the through flow plate (7) in an area of the passage channel (5) is embodied as a sieve or perforated plate with preferably honeycomb-shaped penetrating openings (9). 7. A backflow preventer according to one of claims 1 through 6, characterized in that the through flow plate (7) and the closing body counterpart (4) are connected to one another in one piece. 8. A backflow preventer according to one of claims 1 through 7, characterized in that the closing body (3) is held at the exterior circumference of the through flow plate (7). 9. A backflow preventer according to one of claims 1 through 8, characterized in that the closing body (3) includes a closing body section held at the through flow plate (7) that contacts an interior circumference of the gas or liquid line (2) in a sealing manner. 10. A backflow preventer according to one of claims 1 through 9, characterized in that an upstream face edge region of the closing body (3), contacting the gas or liquid line (2) in a scaling manner, is embodied as an annular cross-sectional enlargement (10). 11. A backflow preventer according to one of claims 1 through 10, characterized in that the closing body (3) is held with the cross-sectional enlargement in a fastening groove (11) provided in an exterior circumference of the through flow plate (7). 2155686499 WP 2004/090394 PCT/EP20fl4J)03724 CLAIMS 1. Backflow preventer (1), which can be inserted into a gas or liquid line (2), comprising a closing body (3) embodied as a hollow body open on a drainage side, which limits a passage channel (5) between the closing body and a central closing body counterpart (4), the closing body (3) being displaceable by a flow medium flowing through the passage channel (5) in a flow direction (Pf 1) from a closed position, contacting the closing body counterpart (4) in a sealing manner into an open position against a restoring force of an elasticity and/or a stability of the closing body, characterized in that the closing body (3), in an unstressed closed position, initially contacts only a partial or edge region (6) of the closing body counterpart (4) with a partial region embodied as a sealing lip (12) of the closing body and can additionally be pressed against the closing body counterpart (4) with a partial region of a longitudinal extension thereof under a pressure of the fluid flowing against the flow direction (Pf 1), opening a downstream buffer volume for back flowing fluid. 2. A backflow preventer according to claim 1, characterized in that a free edge region of the sealing lip (12), which contacts the closing body counterpart (4), is provided with an edge reinforcement (13) to compensate against expansion of an edge region circumference. 3. A backflow preventer according to one of claims 1 or 2, characterized in that the edge reinforcement (13) is embodied as an annular cross-sectional expansion or a cross-sectional enlargement of the closing body (3). 4. A backflow preventer according to one of claims 1 through 3, characterized in that the closing body counterpart (4) has a rounded end section (6) and is preferably embodied in a drop shaped manner. The invention relates to a backflow preventer (1) integrateable into a gas or liquid pipeline (2). The inventive backflow preventer consists of a closing body (3) which is embodied in the form of a hollow body which is open on a drainage side thereof and defines a passage channel (5) between itself and the central counterpart (4) opposite thereto. Said closing body (3) is displaceable by a flow medium flowing through the passage channel (5) in a flow direction (Pf 1) from a sealing contact thereof with said counter part (4) of the closing body to the open position thereof against the opposing force of elasticity and /or stability thereof. Said backflow preventer (1) is easily producible even with a small number of components and is characterised by a high flow and low pressure loss.

Full Text

2155686499
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Translation of PCT/EP2004/003724
Backflow Preventer
The invention relates to a backflow preventer, which can be integrated into a gas or liquid
line and which is provided with a closing body, embodied as a hollow body open at the
drainage side. The closing body limits a passage channel between itself and a central
closing body counterpart, with the closing body being displaceable by the flow medium
flowing through the passage channel from a closing position, contacting the closing body
counterpart in a sealing manner, into an opening position against the restoring force of its
own elasticity and/or own stability.
Such backflow preventers arc inserted into sanitary water lines, for example, in order to
prevent the backflow of water and in particular the return suction of waste water into the
drinking water lines. Such backflow preventers open when the water flows to an outlet.
Here, the closing body is displaced by the flow medium, flowing in the flow direction or
in the direction towards the outlet, from its closed position into the open position against
the restoring force of a return spring. In the event of an undesired backflow, however,
the closing body is pressed firmly against the valve seat and kept in its closing position,
thus blocking the way back for the return flowing water.
The backflow preventers of prior art are usually comparatively complicated and comprise
multiple components, thus they are expensive in their production. Therefore, the object
of the invention is to provide a backflow preventer characterized in a simple construction,
with this simple construction favoring low production costs and operation without
malfunction.
From CH 572 179 Al a backflow preventer of the type mentioned at the outset is known,
which can be inserted into a gas or liquid line. The known backflow preventer is
provided with a cone-shaped closing body on its drainage side which is made from an
elastic material, limiting a passage channel between itself and a central closing body
counterpart. In a closing position the closing body contacts the closing body counterpart

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in a sealing manner, which has a cone-shaped exterior contour and is provided
circumference penetrations at its exterior for the fluid flowing through the closing body
counterpart. The closing body, which contacts the closing body counterpart and thus
closes the penetrations in a tightly sealing manner, is displaced by the fluid flowing
through the passage channel in the flow direction against the restoring force of its own
elasticity in the opening position. In contrast thereto, the fluid flowing opposite the flow
direction is able to additionally press the closing body against the exterior circumference
of the closing body counterpart.
The use of such backflow valves in the field of one-lever mixing faucets is frequently
plagued with the problem that during the closing of the cold water or warm water side,
the water, which is enclosed between the closed backflow valve, on the one hand, and the
also closed valve seat, on the other hand, is heated to a large extent by exterior
influences, until system pressure develops which leads to damages in the weakest part of
the supply line and, thus, frequently at the backflow valve. Ultimately, this can lead to a
blockage of the supply line or an also undesired cross-flow.
Due to the fact that the closing body provided in CH 572 179 A5 is pressed more and
more tightly against the exterior circumference of the closing body counterpart by the
pressure of the fluid flowing back against the flow direction, undesired high pressure can
develop in the backflow preventer known from CH 572 179 A5.
Two backflow preventers having a construction to that described in CH 572 179 A5 are
known from DE 1 154 982 B and DE 842 567 C, with their use also being subject to the
disadvantages and risks described above.
Therefore, the object is to particularly provide a backflow preventer of the type
mentioned at the outset, having a simple design which promotes low production costs and
an operation free from malfunctions, with the backflow preventer also effectively
counteracting any excessive increase in interior pressure,

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In particular, the solution to this objective according to the invention provides in the
backflow preventer of the type mentioned at the outset that the closing body, in its
unstressed closing position, initially only contacts with a partial area, embodied as a
sealing lip, a partial or end region of the closing body counterpart, which narrows in a
direction of the flow, and which can be pressed under the stress of the load of fluid
flowing back against the flow direction into a buffer volume for the back flowing fluid at
the drainage side so that it can additionally be pressed with a partial region of its
longitudinal extension against the closing body counterpart.
The closing body of the backflow preventer according to the invention is embodied as a
hollow body, open on the drainage side, and encompassing a central closing body
counterpart. The hollow body initially contacts only with a partial section, embodied as a
sealing lip, a partial or end section of the closing body counterpart, still not subjected to
any strong backflow. Under the stress of the fluid flowing back opposite the flow
direction, the closing body is additionally pressed against the closing body counterpart
with a partial section of its longitudinal extension, blocking the return path of the back
flowing medium. Here, not only is the sealing surface between the closing body and the
closing body counterpart enlarged and the sealing effect effectively increased, also
between the exterior of the closing body pressed towards the closing body counterpart, on
the one hand, and the encompassing interior wall, on the other hand, a buffer volume on
the drainage side is opened for the back flowing fluid, and thus an undesired and
potentially damaging increase in interior pressure is compensated. When the fluid flows
in the flow direction, though, the closing body is displaced by the flowing medium
flowing through the passage channel from its closing position, in which it contacts the
closing body counterpart in a sealing manner, into an opening position against the
restoring force of its own elasticity and/or own stability. Here the closing body and the
closing body counterpart limit a passage channel, in which a gaseous or liquid flow
medium flows in the flow direction or outlet direction.
Therefore, due to the fact that the closing body is embodied as a hollow body and is made
from an inherently elastic material and due to the fact that in the backflow preventer

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according to the invention a displaceablc valve body made from a hard metal can be
omitted, an undesired development of noise is also avoided during the repositioning of
the closing body from the open position into its closed position and pressure waves which
develop by a fast closing of closing members at the drainage side are dampened. The
pressure wave of backflow preventers of prior art, caused by the fast closing of a closing
member at the drainage side and recognized as a disturbing noise, is reduced and
effectively dampened in the backflow preventer according to the invention by the partial
displacement of the buffer volume provided according to the invention.
In order for the closing body to be able to execute the high number of opening and
closing motions following in rapid sequence it is advantageous for the closing body to be
produced from an elastic material. In order for the medium, flowing back at high
pressure, not to be able to displace the closing body counterpart beyond the narrowing
section, it is advantageous for the sealing lip to be provided, at its free edge region
contacting the closing body counterpart, with a reinforcement at the edge which
counteracts a widening of the circumference of the edge region.
The reinforcement of the edge can be embodied as an annular and non-stretchable
material inlay in the closing body edge region, for example. The simple production of
the backflow preventers according to the invention is promoted, though, when the edge
reinforcement is embodied as a circumferential, cross-sectional expansion or cross-
sectional enlargement of the closing body.
A preferred embodiment according to the invention provides for the closing body to have
a rounded end region and to be embodied preferably in a drop-shaped manner. In this
embodiment the high throughput and the little loss in pressure of the backflow preventer
according to the invention is favored even more.
In order to hold the closing body counterpart in the desired central position inside the
closing body, embodied as a hollow body, it is advantageous for the central closing body

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counterpart to be connected to a through flow plate, provided with flow openings which
open into the passage channel.
The through flow plate, in the area of the passage channel, is characterized in a flow
resistance being as little as possible, when the through flow plate is embodied in the area
of the passage channel as a sieve or perforated plate with flow openings embodied
preferably honcycomb-shaped.
The simple production of the backflow preventer according to the invention is favored
even more, when the through flow plate and the closing body counterpart are connected
to one another in one piece.
An embodiment according to the invention which is produced in a particularly simple and
cost-effective manner, provides for the closing body to be held to the exterior
circumference of the through flow plate.
In order to be able to produce the backflow preventer according to the invention with
little expense and from only few components it is advantageous for the closing body with
its closing body section held to the through flow plate to contact the interior
circumference of the gas or liquid pipeline. In this embodiment a separate annular seal
can be omitted. Instead of such an annular seal, the closing body performs the function
with its closing body section contacting the interior circumference of the gas or liquid
line.
In order to enhance such sealing function even further it is advantageous for the edge
region of the face of the closing body, contacting upstream the gas or liquid line in a
sealing manner, is embodied as a circumferentially extending cross-sectional
enlargement. Here, a particularly advantageous further development according to the
invention provides for the closing body to be held with its cross-sectional enlargement in
a holding groove provided at the exterior circumference of the through flow plate.

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The reduced production expense is enhanced even further when the backflow preventer is
essentially formed in two parts and the closing body, on the one hand, is provided both
with a closing body counterpart and, on the other hand, with the through flow plate
connected thereto in a single piece.
Additional features of the invention are discernible from the following description of an
embodiment according to the invention in connection with the claims and the drawing.
The individual features can be embodied alone or combined in an embodiment according
to the invention.
In the drawings:
Fig. 1: a backflow preventer, which can be inserted into a gas or liquid pipeline, shown in
a cross section, in its original or closed position not subjected to any flow medium
Fig. 2: the backflow preventer according to Fig. 1, with the backflow preventer is shown
in its closed position on the left of the central axis and in its open position on the
right of the central axis, and
Fig. 3: a top view of the backflow preventer according to Figs. 1 and 2 on a through flow
plate provided upstream.
In Figs. 1 through 3 the backflow preventer is shown, which can be inserted into a gas or
liquid line, and here it is integrated in a sanitary water line 2. The backflow preventer 1
is provided with a closing body 3 embodied as an essentially pot-shaped hollow body
open at the drainage side.
As clearly discernible from the closed or normal position of the backflow preventer 1,
shown in Fig. 1 unimpinged by the flow medium, the closing body 3 limits a passage
channel 5 between itself and a central closing body counterpart 4.

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In the left half of Fig. 2 it is shown how the closing body 3, made from an elastic or
shape-elastic material is additionally defined in the closed position by the back flowing
flow medium impinging the closing body 3 on its exterior, causing a large partial section
of its longitudinal extension to be pressed against the closing body counterpart 4. Here,
the closing body contacts the closing body counterpart 4 under the pressure of the fluid
flowing back opposite the flow direction such that between the closing body and the
encompassing interior wall of the pipeline a downstream buffer volume is opened for the
back flowing fluid. By opening the downstream buffer volume, any undesired increase in
interior pressure is compensated, which otherwise might damage the gas or liquid
pipeline and/or the functional unit integrated therein. Across therefrom, the backflow
preventer 1 is shown in the right half of Fig. 2 in its opening position. Here it is obvious
that the dosing body 3 can be displaced by the flow medium flowing in the flow
direction Pfl through the passage channel 5 from a closed position, contacting a closing
body counterpart 4 in a sealing fashion, into an open position against the restoring force
of its own elasticity or its own stability.
In Figs. 1 and 2 it is discernible that the closing body counterpart 4 made from a
dimensionally stable material, has an end region, which narrows in the flow direction Pfl
in a rounded fashion, here. For this purpose, the closing body counterpart 4 is embodied
essentially drop-shaped. Here, the closing body counterpart 4 is connected in one piece
with the upstream tip of a drop-shaped through flow plate 7, aligned laterally to the flow
direction Pfl, which contacts with its edges at least one rest, here embodied as an annular
flange 8, in the gas or liquid line 2.
It is possible for at least one feeder channel to be penetrated by the closing body
counterpart 4, which opens into the passage channel 5. However, here the through flow
plate 7 is provided with penetrating openings 9, that open into the passage channel 5.
From the top view onto the upstream face of the through flow plate 7, shown in Fig. 3, it
is discernible that in the area of the passage channel, said blow plate is embodied as a
sieve or perforated plate with preferably honeycomb-shaped penetrating holes 9.

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The closing body 3 is held to the exterior circumference of the through flow plate 7.
Here, the closing body 3 contacts with its closing body section, held to the through flow
plate 7, the interior circumference of the gas or liquid pipeline 2 in such a sealing manner
that any additional annular seal between the backflow preventer 1 and the gas or liquid
pipeline 2 can be omitted.
In order to improve the sealing effect of the closing body 3 in this area even more, the
edge region of the face of the closing body 3, upstream contacting the gas or liquid line 2
in a sealing manner, is embodied as an annular-shaped encircling cross-sectional
enlargement 10. Here, it is discernible in Figs. 1 and 2 that the closing body 2 is held
with its cross-sectional enlargement 10 to a mounting groove 11 provided at the exterior
circumference of the through flow plate 7.
At its downstream partial region, the closing body 3 is embodied as a narrowed and
rounded scaling lip 12, which contacts the end region 6 of the closing body counterpart 4.
In order for the closing body 3 to additionally be pressed against the closing body
counterpart 4, serving as a valve seat, by the flow medium impinging it from the outside
and flowing in the opposite flow direction Pf2, and thus also preventing the edge region
of the closing body 3, contacting the closing body counterpart 4 with the edge region
from being pushed by the high pressure of back flowing medium, over the tapering end
section 6 of the closing body counterpart 4, the scaling lip 12 is provided at its free edge
region contacting the closing body counterpart 4 with an edge reinforcement 13
counteracting any expansion of the edge region circumference. This edge reinforcement
13 is here embodied as a circumferentially extending cross-sectional expansion or cross-
sectional enlargement of the closing body 3.
The closing body 3 of the backflow preventer 1 shown here is embodied as a hollow body
open at the drainage side, encompassing the central closing body counterpart 4. The
closing body 3 and the closing body counterpart 4 define between each other the passage
channel 5 through which a gaseous or liquid flow medium flows in the flow direction or
towards the outlet Pf 1. Here, the closing body 3 is displaced by the flow medium

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flowing through the passage channel 5 from the closing position, sealing at the closing
body counterpart 4, against the restoring force of its own elasticity and/or own stability
into its opening position. However, in the event of backflow of the flow medium in the
opposite direction Pf2, the closing body 3, impinged on the outside by the back flowing
medium, is held in its closing position, which blocks the backward flow of the back
flowing medium.
A particular advantage of the backflow preventer 1 shown here is the fact that it can be
produced inexpensively and from very few components. The backflow preventer 1
shown here is embodied in two components and essentially comprises, on the one hand,
the closing body counterpart 4 connected in one piece to the through flow plate 7 and, on
the other hand, the closing body 3. The backflow preventer shown here is characterized
in a high flow capacity and a comparatively low pressure loss.

2155686499
Amended Claim 1 under Article 19
1. Backflow preventer (1), which can be inserted into a gas or liquid line (2), comprising a
closing body (3) embodied as a hollow body open on a drainage side, which limits a
passage channel (5) between the closing body and a central closing body counterpart (4),
the closing body (3) being displaceable by a flow medium flowing through the passage
channel (5) in a flow direction (Pf 1) from a closed position, contacting the closing body
counterpart (4) in a sealing manner, into an open position against a restoring force of an
elasticity and/or a stability of the closing body, wherein the closing body (3), in an
unstressed closed position, initially contacts only a partial or edge region (6) of the
closing body counterpart (4) with a partial region embodied as a sealing lip (12) of the
closing body and can additionally be pressed against the closing body counterpart (4)
with a partial region of a longitudinal extension thereof under a pressure of the fluid
flowing against the flow direction (Pf 1), opening a downstream buffer volume for back
flowing fluid, characterized in that the closing body (3) is non-removably held on the
backflow preventer in the gas or liquid line.
2. A backflow preventer according to claim 1, characterized in that a free edge region of the
sealing lip (12), which contacts the closing body counterpart (4), is provided with an edge
reinforcement (13) to compensate against expansion of an edge region circumference.
3. A backflow preventer according to one of claims 1 or 2, characterized in that the edge
reinforcement (13) is embodied as an annular cross-sectional expansion or a cross-
sectional enlargement of the closing body (3).
4. A backflow preventer according to one of claims 1 through 3, characterized in
that the closing body counterpart (4) has a rounded end section (6) and is
preferably embodied in a drop shaped manner.

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5. A backflow preventer according to one of claims 1 through 4, characterized in
that the central closing body counterpart (4) is connected to a through flow plate
(7), which has penetrating openings (9) which open into the passage channel (5).
6. A backflow preventer according to one of claims 1 through 5, characterized in
that the through flow plate (7) in an area of the passage channel (5) is embodied
as a sieve or perforated plate with preferably honeycomb-shaped penetrating
openings (9).
7. A backflow preventer according to one of claims 1 through 6, characterized in
that the through flow plate (7) and the closing body counterpart (4) are connected
to one another in one piece.
8. A backflow preventer according to one of claims 1 through 7, characterized in
that the closing body (3) is held at the exterior circumference of the through flow
plate (7).
9. A backflow preventer according to one of claims 1 through 8, characterized in
that the closing body (3) includes a closing body section held at the through flow
plate (7) that contacts an interior circumference of the gas or liquid line (2) in a
sealing manner.
10. A backflow preventer according to one of claims 1 through 9, characterized in
that an upstream face edge region of the closing body (3), contacting the gas or
liquid line (2) in a scaling manner, is embodied as an annular cross-sectional
enlargement (10).
11. A backflow preventer according to one of claims 1 through 10, characterized in
that the closing body (3) is held with the cross-sectional enlargement in a
fastening groove (11) provided in an exterior circumference of the through flow
plate (7).

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CLAIMS
1. Backflow preventer (1), which can be inserted into a gas or liquid line (2),
comprising a closing body (3) embodied as a hollow body open on a drainage
side, which limits a passage channel (5) between the closing body and a central
closing body counterpart (4), the closing body (3) being displaceable by a flow
medium flowing through the passage channel (5) in a flow direction (Pf 1) from a
closed position, contacting the closing body counterpart (4) in a sealing manner
into an open position against a restoring force of an elasticity and/or a stability of
the closing body, characterized in that the closing body (3), in an unstressed
closed position, initially contacts only a partial or edge region (6) of the closing
body counterpart (4) with a partial region embodied as a sealing lip (12) of the
closing body and can additionally be pressed against the closing body counterpart
(4) with a partial region of a longitudinal extension thereof under a pressure of the
fluid flowing against the flow direction (Pf 1), opening a downstream buffer
volume for back flowing fluid.
2. A backflow preventer according to claim 1, characterized in that a free edge
region of the sealing lip (12), which contacts the closing body counterpart (4), is
provided with an edge reinforcement (13) to compensate against expansion of an
edge region circumference.
3. A backflow preventer according to one of claims 1 or 2, characterized in that the
edge reinforcement (13) is embodied as an annular cross-sectional expansion or a
cross-sectional enlargement of the closing body (3).
4. A backflow preventer according to one of claims 1 through 3, characterized in
that the closing body counterpart (4) has a rounded end section (6) and is
preferably embodied in a drop shaped manner.
The invention relates to a backflow preventer (1) integrateable into a gas or liquid pipeline (2). The inventive backflow preventer consists of a closing body (3) which is embodied in the form of a hollow body which is open on a drainage side thereof and defines a passage channel (5) between itself and the central counterpart (4) opposite thereto. Said closing body (3) is displaceable by a flow medium flowing through the passage channel (5) in a flow direction (Pf 1) from a sealing contact thereof with said counter part (4) of the closing body to the open position thereof against the opposing force of elasticity and /or stability thereof. Said backflow preventer (1) is easily producible even with a small number of components and is characterised by a high flow and low pressure loss.

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Patent Number

219510

Indian Patent Application Number

01868/KOLNP/2005

PG Journal Number

19/2008

Publication Date

09-May-2008

Grant Date

07-May-2008

Date of Filing

19-Sep-2005

Name of Patentee

NEOPERL GMBH

Applicant Address

KLOSTERRUNSSTRASSE 11, 79379 MULLHEIM, GERMANY.

Inventors:

#	Inventor's Name	Inventor's Address
1	FANGMEIER, MARTIN	LIESTENGASSE 2C, 79424, AUGGEN, GERMANY.

PCT International Classification Number

F16K 15/14

PCT International Application Number

PCT/EP2004/003724

PCT International Filing date

2004-04-07

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	103 16 903.2	2003-04-12	Germany