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Timestamp: 2013-05-25 03:06:08
Document Index: 187068313

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Backflow Preventer Inventor Store
Patents sorted by company.	10/26/06 | Class 137 Monitor | RSS | Browse: Prev - Next Backflow preventer Abstract: 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. ...
Agent: Volpe And Koenig, P.C. - Philadelphia, PA, USInventor: Martin FangmeierUSPTO Applicaton #: #20060237076 - Class: 137853000 (USPTO) - 10/26/06 - Class 137 The Patent Description & Claims data below is from USPTO Patent Application 20060237076, Backflow preventer.
[0001] 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
[0002] Such backflow preventers are 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.
[0003] 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
[0004] From CH 572 179 A1 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
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
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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 according to the invention a
displaceable 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
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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 counterpart to be connected
to a through flow plate, provided with flow openings which open into the
passage channel.
[0016] 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
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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
[0022] 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
[0024] 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
[0025] 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,
[0026] FIG. 3: a top view of the backflow preventer according to FIGS. 1
and 2 on a through flow plate provided upstream.
[0027] 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.
[0028] 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.
[0029] 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 closing body 3 can
be displaced by the flow medium flowing in the flow direction Pf1 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.
[0030] 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 Pf1 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 Pf1, which contacts
with its edges at least one rest, here embodied as an annular flange 8,
in the gas or liquid line 2.
[0031] 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 through flow
plate is embodied as a sieve or perforated plate with preferably
honeycomb-shaped penetrating holes 9.
[0032] 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.
[0033] 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.
[0034] At its downstream partial region, the closing body 3 is embodied as
a narrowed and rounded sealing 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 sealing 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.
[0035] 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 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.
[0036] 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
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