Note: Descriptions are shown in the official language in which they were submitted.
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Field of the Invention
The present invention relates to a safety device for
preventing water from flowing back into a supply line of a sanitary
fittiny.
Sanitary fittings exist wherein if dirty water is sucked
back into the supply line, the quality of the feed-water may be put
at risk. These fittings include in particular wash-basin and sink
fittings with a pull-out hose sprayhead, as well as shower and bath
regulators with a hose sprayhead. It may occur with such fittings
that the sprayhead lies in a basin or in a bath while, for example,
the supply line is broken. If the control cartridge of the fitting
is then opened, the basin or the bath may be emptied through the
sprayhead as a result of the low pressure, (i.e. vacuum) which is
built up in the supply line as a result of the water having flowed
out. These fittings must have safety devices by means of which
dirty water is prevented from being sucked back into the supply
line.
A safety device of this type is ~nown from German Offen-
legungsschrift 3,603,503. The fitting described in this German
Offenlegungsschrift has~a shut-off valve which is inserted into the
flow path between the supply line and the outlet of the fitting.
A venting path, into which a valve of the safety device is inserted,
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branches off from the flow path downstream from the shut-off valve
as seen in the direction o flow of the water. This valve is
des~igned as a sensitive nonreturn valve which is situated under
normal operating conditions in the closed position. The valve opens
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automatically under conditions enabling backElow and vents the
supply line and the flow path in order to prevent the water from
flowing back. It is now possible, under normal operating con-
ditions, for a vacuum to be built up momentarily in the flow path
following the shut-off valve/ in particular if the shut-off valve
closes quickly, as a result of which the valve of the safety device
can be forced to open/ which may have the consequence that water
penetrates through this valve in drops. In order to prevent this,
German Offenlegungsschrift 3,805,462 proposes arranging two valves
10 in the venting path, one behind another in such a way that, when the
water dispensing process is suddenly interrupted, the vacuum affects
only the first valve lying closer to the flow path. The delay be-
tween the two valves ensures that the second valve does not open
under these operating conditions, so that a drop of water penetrat-
ing through the first valve is caught in the region between the two
valves. In the event of low pressure vacuum of longer duration, as
occurs under conditions enabling backflow, both valves of the safety
device open in order to vent the supply line and the flow path and
to prevent water from flowing back into the supply line.
SUMMARY OF THE INVENTION
Starting from the above-noted state of the art, it is an
objeot of the present invention to provide a safety device for a
sanitary fitting which is functionally reliable and prevents water
from penetrating through the venting path even when the shut-off
valve is closed suddenly.
The lnvention provides a safety device for preventing
water from flowlng back into a supply line of a sanitary fitting
~which comprlses: a shut-off valve inserted into a flow path
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conducting the water from the supply line to an outlet; a venting
means for connecting the outlet to the surrounding air; a valve
inserted into the venting means, which valve is closed under normal
operating conditions and open under conditions enabling backflow in
order to vent the supply line; and an actuating member, pressured
by the flow in the flow means and connected to the valve body of
the valve, wherein said actuating member is automatically movable
by the flow of the water under conditions enabling backflow from
an operating position of the actuating member assumed under normal
operating conditions, in which the valve is held closed, into a
backflow postion, and wherein movement into the backflow position
of said actuating member causes opening of the valve.
Under normal operating conditions, the actuating member is
held in the operatLng position by the flow, which ensures that
under these conditions the valve is at all times closed. As a
result, the low pressure or vacuum built up by the closing oE the
shut-off valve cannot open the valve, even when the flow of water
is suddenly interrupted. Under conditions enabling backflow, the
actuating member is under pressure in the opposite direction to the
flow, which causes the actuating member to be moved into a backflow
position. As a result of this movement into the backflow position
the valve is forciblyopenedby the active connection between the
actuating member and the valve body. Under conditions enabling
backfio~, the supply line ls consequently unfaillngly vented.
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BRIEF DESCRIPTION OF THE DR~NINGS
The present invention will now be descri~ed in more detail
with reference to the exemplary embodiments shown in the drawings,
in which purely diagrammatically:
Fig. 1 shows in partial section a sink fitting with a pull-out
hose sprayhead and a safety device;
Figs. 2 and 3 show a first embodiment of a safety device under
normal operating conditions and under conditions enabling backflow,
respectively;
Figs. 4 and 5 show the safety device corresponding to Figs. 2
and 3 respsctively in plan view and in a horizontal sectional view
taken along line V in Fig. 2;
Figs. 6 and 7 show a second embodiment of the safety device,
and
Figs. 8 and 9 show the safety device corresponding to Figs. 6
and 7 equipped with a throttle element.
DESCRIPTION OF THE PREFERRED EMBODIM~NTS
The sanitary fitting shown in Fig. 1 has a fitting housing 10
and a pull-out type hose sprayhead 120 The fitting housing 10
essentially consists of three parts, these being a lower and an
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upper housing part 14 and 16, respectively, which form a Pixed
housing part 16a, as well as a casing element 20 mounted on the
latter so as to be able to pivot about an axis 18 extending in the
vertical directlon. The lower housing part 14 is designed
essentially in the form of a sleeve, so as to pierce, with a
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fastening connector 22, an approximately horizontall~ extending
edge 24 or a sink 26 and is held on the sink 26 by means of a nut
28 screwed onto the fastening connector 22. The upper housing part
16 is seated on the lower housing part 14 and fastened thereto.
The essentially cylindrical and fixed housing part 16a, formed from
the lower and upper housing part 14, 16, is surrounded by the
casing element 20 which is mounted thereon so as to be able to
pivot about the axis 18.
The upper housing part 16 has a cylindrical housing recess
30 open at the top and in the form of a blind hole, into which a
control cartridge 32, indicated only diagrammatically, ls inserted.
The control cartridge 32 is a single-lever mixing valve, as is
generally known and described in detail, for example, in Swiss
Patent Specifications 651,119 and 654,088. On the inlet side, the
control cartridge 32 is connected to supply lines 34 for cold and
warm water, only one of the supply lines 34 being shown in Fig. 1.
The supply lines 34 are led through the fastening connector 22 and
the lower housing part 14 from below and open out into a bore, not
shown, in the upper housing part 16, which bore connects the supply
20 ~ lines 34 to the control cartridge 32 on the inlet side.
A safety device 36, indicated only diagrammatically in
this figure, is connected downstream from the control cartridge 32
and is inserted into a further housing recess 38 in the upper
housing part 16 which is open on the side facing the lower housing
part 14 and is in the form of a blind hole. A passage opening 40,
which cornects the control cartridge 32 to the safety device 36 in
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flow, is provided between the housing recess 30 and the further
housing recess 38. A tube 42, which is led through the fastening
connector 22 under the sink 26l leads away and downwards from the
safety device 36 in the direction of the axis 18. The end of the
tube 42 on this side is connected to a flexible hose 44 of the hose
sprayhead 12, which hose is led with the other end region back
through the fastening connector 22, forming a storage loop
underneath the sink 26. The lower housing part 14 has an opening
46 extending approximately in a radial direction and through which
the end region of the hose 44 is passed into a neck 48 integrally
formed on the casing element 20 and projecting from the latter
obliquely upwards. The hose 44 opens into a sprayhead 50 the
handle 50', of which, with the end region on the hose side, is
plugged into a guide bush 48' arranged in the neck 48 and can be
pulled out from it again. The outlet of the hose sprayhead 12 is
designated by number 52. The opening 46 for the hose 44 is
designed so as to be so large in the circumferential direction of
the lower housing part 14 that it is possible for the casing
element 22 to easily pivot about the axis 18.
A venting channel 54, which runs from the further housing
recess 38 to the neck 48, is provided in the upper housing part 16.
~A hole 56 is provided on the upper side of the neck 48, which,
forming a venting path 58 together with the neck 48 and the venting
channel 54, connects the safety device 36 to the surrounding air.
A further possible embodiment of the venting path 58 is described
in Swiss Patent Application 04 481/89-9. The flow path 60 connects
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the supply line 34 to the outlet 52. It runs through the control
cartridge 32, the safety device 36, situated downstream from the
latter when seen in the direction of flow S of the water, the tube
42, the hose 44 and the sprayhead 50.
A first embodiment of the safety device 36 is illustrated
in Figs.2 and 3, shown in vertical section under normal operating
conditions and under conditions enabling backflow respectively.
The safety device 36 is inserted from below into the
further housing recess 38 of the upper housing part 16. The safety
device 36 is more advantageously fastened to the upper housing part
16 in such a way that it can be dismantled easily, for example for
maintenance. It is thus possible to design the safety device 36
such that it can be screwed into the upper housing part 16 or
fastened in a known manner by means of screws, as shown in Figs. 6
and 7, having studs or spring rings. The passage opening 40, which
connects in terms of flow the safety device 36 inserted downstream
- as seen in the direction of flow S of the water - from the control
cartridge 32 to the latter, opens into the further recess 38 from
above (cf. also Fig. 1). The flow path connecting the supply line
to the outlet 52 is indicated in Figures 2 and 3 by an arrow 60.
The venting channel 54 of the venting path 58 opens into the
further housing recess 38 laterally.
The safety device 36 has a housing 62 which is essentially
symmetrical in rotation~about the axis 38' of the cylindrical
further housing recess 38, is introduced into the further housing
recess 38 from below and extends to a point above the venting
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channel 54. On the side facing the passage opening 40, the housing
62 has a recess 64 in the form of a blind hole and symmetrical in
rotation about the axis 38', in which an actuating body 68 is
arranged, which body is designed as an actuating member for a valve
66 and is likewise essentially symmetrical in rotation. An annular
valve seat 70 extending about the axis 38, which borders a vent
opening 72, is located on the base 64', of the recess 64O The vent
opening 72 extends from the valve seat 70, firstly downwards in the
direction of the axis 38' and then radially to a circumferential
groove 74 which is provided on the housing 62 and is connected in
terms of flow to the venting channel 54. The vent opening 72 is
part of the venting path 58 and, with the valve 66 open (Fig. 3),
connects the flow path 60 to the venting channel 54, and thus to
the surrounding air.
Around the valve seat 70, the base 64' has a groove-shaped
depression 76 from which originate flow bores 78 extending parallel
to the axis 38' and opening out at their lower end into an outlet
opening 80 in the housing 62. The outlet opening 80 is connected
in terms of flow to the tube 42 which is tightly inserted into a
cylindrical outlet passage 82 attached to the housing 62 and
extending in the direction of the axis 38', and held therein.
The actuating body 68 has a lower body part 84 and a
perforated disk 86 bearing against the latter from above. Flow
passages 88, which are arranged in two circles concentric with the
axis ~38', are aligned with one another and extend parallel to the
axis 38', ext-n- through the perforated disk 86 and the body part
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84, as is evident especially clearly in the plan view of the safety
device 36 shown in Fig. 4. The flow passages 88 open into a cup-
or bell-shaped cavity 90, which is open in a downward direction, in
the body part 84. The perforated disk 86 is secured on the body
part 84 by a set screw 92 projecting into the cavity 90, bearing
against the body part 84 with a screw shoulder 94 and piercing the
body part 84 with its screwthread 94' adjoining the screw shoulder
94 in an upward direction. The screwthread 94' is screwed into a
~orresponding counterthread in the perforated disk 86. A valve
body 98 of the valve 66, which valve body has a sealing lip 100
interacting with the valve seat 70 at its lower end region, is
seated on the stem 96 of the set screw 92. The valve body 98 is
held on the stem g6 between the head 94" of the set screw 92 and a
guard screen 102 integrally formed with the stem 96. The guard
screen 102 provided between the screw shoulder 94 and the valve
body 98 widens conically, as seen in the direction of flow S, and
tapers in one step, forming a flank 102' against which the valve
body 98 abuts. The annular valve body 98, made from rubber-elastic
material, has a shape similar to that of the guard screen 102, the
sealing lip 100 being separated by a circumferential groove 100'
from the part of the valve body 98 widening conically. The profile
of the guard screen 102 and of the valve body 98 forms, in vertical
se~tion,~a sawtooth shape, whose steep flanks face away from the
direction of flow S.
At the upper end, the safety device 36 has a sealing member
104~made from rubber-elastic material which is designed in the form
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of a rolling diaphragm. The annular and, in cross-section,
U-shaped sealing member 104 surrounds the upper end 62' of the
housing 62 and is held securely clamped at its inner end region
between the body part 84 of the actuating body 68 and the
perforated disk 86. ~t its outer end region, the sealing member
104 has a circumferential bead 104' which engages in a
circumferential securing groove 106 in the housing 62 and bears,
along its circumference, against the upper housing part 16. The
sealing member 104 thus prevents water from flowing through between
the housing 62 and the actuating body 68, but at the same time
seals off the circumferential groove 74 with its bead 104' so that
no water can pass between the housing 62 and the upper housing part
16 into the circumferential groove 74, and thus into the venting
path 58.
A circumferential sealing groove 108, in which an 0-ring 110
is arranged which bears against the upper housing part 16 below the
venting channel 54 on the circumference side in order to seal off
the venting path 58 from the surroundings in the region of the
safety device 36, is integrally formed with the housing 62 beneath
the circumferential groove 74. The invention thus serves to
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prevent any water penetrating into the venting path 58 from being
able to flow out in an uncontrolled manner from the fitting.
As shown in Fig. 2, the actuating body 68 is situated in the
operating position assumed under normal operating conditions. In
this operating position, the actuating body 68 is supported by a
; shoulder 112 integrally formed with the body part 84, counter to
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the direction of flow S, against a stop 114 on the housing 62
interacting with this shoulder 112. It is thus ensured that under
normal operating conditions the sealing lip lO0 bears precisely
against the valve seat 70.
At its lower end region, the body part 84 has a sliding bead
116 by means of which the actuating body 68 is guided smoothly on
the housing 62 in and counter to the direction of flow S.
Calcification of the safety device 36 between the sliding bead 116
and the sealing member 104 in the region between the housing 62 and
the actuating body 68 is thereby also prevented.
In Fig. 3, the actuating body 68 is shown as being raised into
the backflow position 68' counter to the direction of flow S. The
sealing member 104 in the form of a diaphragm here abuts, at the
upper end 38'' of the further housing recess 38, the upper housing
~art 16 and limits movement of the actuating body 68 counter to the
direction of flow S. Since the valve body 98 is connected rigidly
to the actuating body 68, with the actuating body 68 being situated
in the backflow position 68', the valve 66 is opened by the sealing
lip 100 being lifted off the valve seat 70. In this case, the flow
path 60, and thus the supply line 34 (see also Fig. 1), is
connected to the venting path 58, and thus to the surrounding air,
and i5 vented.
Fig. 5 shows a sectional view taken along the height of the
line V in Fig. 2 through a further possible embodiment of the
housing 62 of the safety device 36. The vent opening 72 extends in
this embodiment initially in the direction of the axis 38', and
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then forks into two arms 72' extending in a radial direction which
are aligned with each other. On both sides of the two arms 72'
three flow bores 78 extend in each case in the direction of the
axis 38', and connect the recess 64 in the housing 62 to the outlet
opeining 80 (cf. also Figures 2 and 3). The flow bores 78 are
distributed in a circle about the axis 38'.
The safety device 36 shown in Figures 2 to 5 works as
follows: under normal operating conditions, the actuating body 68
is situated in the operating position shown in Fig. 2. The valve
66 is closed here and the flow path 60 is thus separated from the
venting path 58. When the control cartridge 32 is opened (cf. Fig~
1), the water flows in the direction of flow S through the passage
opening 40 into the further housing recess 38 and thereby pressures
the actuating body 68 and the sealing member 104. The shoulder 112
abutting-the stop 114 thus prevents movement of the actuating body
68 in the direction of arrow S counter to the force generated by
the stress of the water in the direction of flow S. The sealing
lip 100 of the valve 66 consequently bears precisely against the
valve seat 70. The water flows along the flow path 60 through the
flow passages 88 in the actuating body 68 to the cavity 90 from
where, flowing through the flow bores 78, it passes into the outlet
opeing 80. From here the water is conveyed through the tube 42,
the hose 44 and the spayhead 50 to the outlet 52. The guard
screen 102 and the thickened section on the valve body 98 meanwhile
prevent the sealing lip 100 from being pressured directly by the
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water flowing through the flow passages 88 and from suffering
damage as a result.
Even when the water dispensing process is shut off
suddenly by quickly closing the control cartridge 32, the valve 66
remains closed since, in spite of a low pressure or vacuum which
may have built up as a result in the part of the flow path 60 down-
stream from the control cartridge 32 when seen in the direction of
flow S, the actuating body 68 is drawn by the inertia of the column
of water in the direction of flow S, which prevents the sealing lip
100 from lifting off the valve seat 70. Under normal operating
conditions, the possibility of water penetrating through the venting
path 58 is consequently prevented.
If the extremely rare situation occurs where, with the
control cartridge 32 open, a low pressure or vaccum is created in
the feed line 34, the water then attempts to flow back into the
supply line counter to the direction of flow S, the actuating body
68 is thus stressed counter to the direction of flow S, which
results in it being raised from the operating position shown in
Fig. 2 into the backflow position 68' shown in Fig. 3. The valve
66 is thus compuIsorily opened. This now results in the supply
; line 34 being connected to the surrounding air by the venting path
58 and the flow path 60, and consequently being vented. Water as a
result is prevented from being subsequently drawn from the outlet
52 into the supply line 34. The sawtooth-shaped embodiment of the
guard screen
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102 and of the valve body 98 has a larger flow resistance counter
to the direction of arrow S than in the direction of arrow S,
which, under conditions enabling back flow, increases the force
counter to direction of arrow S for raising the actuating body 68
into the backflow position 68'. As a result, an even more rapid
opening of the valve 66 is obtained. It should be taken into
consideration that, with the valve 66 open, the outlet side of the
fitting is also vented by the. venting path 58. When fresh water is
first conveyed in the direction of flow S, the actuating body 68 is
then transferred immediately back into the operating position by
the stress, which causes the valve 66 to close.
Figures 6 and 7 show, in a vertical section, a further
embodiment of the safety device 36, which is very similar to the
embodiment shown in Figures 2 to 4. The essential difference is
that a nonreturn valve 118 is provided in the outlet opening 80 and
closes automatically under conditions enabling backflow, in order
to prevent water from being sucked through the outlet 52. The
parts corresponding to each other in Figures 6 and 7~ and 2 and 3
respectively are provided with identical reference numerals and
will only be described further where this is necessary for
understanding of Figures 6 and 7. For further details, reference
should be made to the corresponding description of Figures 2 to 4.
The safety device 36 is inserted from below into the further
housing recess 38 of the upper housing part 16 and is held by means
of a locking screw 120 extending in the radial direction relative
i: to the axis 38' and screwed into the upper housing part 16. The
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locking screw 120 has a frustoconical tip at its end region facing
the housing 62 of the safety device 36 and engages into a securing
groove 122 provided circumferentially on the housing 62.
On the side facing the passage opening 40, the housing 62,
which is essentially symmetrical in rotation about the axis 38',
has the recess 64 in the form of a blind hole in which the
actuating body 68 for the valve 66 is provided. The annular valve
seat 70 of the valve 66, which seat delimits the vent opening 72,
is designed on the base 64' of the recess 64. This vent opening 72
extends from the valve seat 70, firstly downwards in the direction
of the axis 38' and subsequently in the radial direction to the
circumferential groove 74 which is integrally formed on the housing
62 and connected in terms of flow to the venting channel 54 in the
upper housing part 16. The valve 66 thus separates the venting path
58 from the flow path 60 of the water. The depression 76 in the
base 64', away from which depression the flow bores 78 extend
parallel to the axis 38' to the outlet opening 80, extends around
the~valve seat 70. These flow bores 78 are arranged in a circle
around the axis 38'.
The nonreturn valve 118 provided in the outlet opening 80 has
a valve body element 124 which is made from rubber-elastic
materlal, is in the form of an annular disk and is securely clamped
with its inner end region by means of a screw 126 between the upper
wall 80 of the outlet opening 80 and a washer 128. As seen in
the radial direction, the washer 128 ends before thP flow bores 78
open into~the outlet opening 80 and is bent downwards at its outer
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edge region. seyond the clamping region between the upper wall 80'
and the washer 128, the valve body element 124 is bent downwards in
the shape of a bell, when water flows in the direction of flow S,
as is shown in Fig. 6. If, on the other hand, no water flows, the
valve body element 124 bears, as a result of its inherent
stiffness, against the upper wall 80' (cf. Fig. 7). The bent-back
edge of the washer 128 prevents injury to the valve body element
124 when it is stressed by the water flowing out from the flow
bores 78 in the direction of flow S. The screw 126 pierces, with
its shank, as one moves away from the vent opening 72, the housing
wall 62 " between the vent opening 72 and the outlet opening 80,
the annular valve body element 124 and the washer 128, and a nut
126' is seated on it from below.
A connecting flange 130, in which the end region of the tube
42 on this side is inserted and secured, is screwed into the
downwardly pointing outlet opening 80. The outlet opening 80 is
sealed off relative to the surroundings by means of an 0-ring 132
which is laid in an undercut 134 behind the screw thread 130' of
the connecting flange 130 and bears against the housing 62 on the
circumference side.
In Flg. 7, the nonreturn valve 118 is shown under conditions
enabling backflow. If water attempts to flow counter to the
direction of flow S from the outlet 52 (cf. Fig. 1) in the
direction towards the supply line 34, the rubber-elastic valve body
element 124 is stressed from below, which results in the valve body
element 124 being pressed against the upper wall 80' and the
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openings of the flow bores 78 being tightly sealed. Water as a
result is prevented from flowing back counter to the direction of
flow S.
The actuating body 68 has the lower body part 84 which is
essentially symmetrical in rotation and the perforated disk 86
arranged above it and bearing against it. Flow passages 88, whi~h
are aligned with one another, are arranged in a circle about the
axis 38' and extend parallel to this axis 38', extend through the
perforated disk 86 and the body part 84. The bell- or cup-shaped
cavity 90, into which the flow passages 88 open and which is open
in a downward direction, is integrally formed on the body part 84.
The valve body 98, interacting with the valve seat 70 and with
which the sealing lip 100 is integrally formed on the side facing
the valve seat 70, is provided in this cavity 90. The annular
valve bodv 98 is seated on a stem 136 which extends in the
direction of the axis 38', bears with a stem shoulder 136' against
the body part 84, penetrates the latter and engages with its upper
end region into a blind hole 138 in the perforated disk a6. The
stem 136 is designed with a finned or ribbed shape at its end
region engaging into the blind hole 138 in order to hold the stem
.
136 in the perforated disk 86. Downstream from the stem shoulder
136', when viewed in the direction of flow S, the guard screen 102
widening out conically is designed on the stem 136 and tapers,
forming the:flank~102', in the form of a step. A rib 136 " is
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integrally formed on the lower end region of the stem. The valve
body 98 seated on the stem 136 is held between this rib 136 " and
the flank 102', fixed in terms of displacement.
The upper end 62' of the housing is surrounded by the rolling
diaphragm-like sealing member 104, U-shaped in cross section and
made from rubber-elastic material, which sealing member is secured
at its outer end by means of the bead 104l engaging into the
securing groove 106 of the housing 62. On the circumference side,
the bead 104' bears against the upper housing part 16. The bead
104' thus also seals off the circumferential groove 74 from above.
The sealing member 104 is clamped with its inner end region between
the body part 84 and the perforated disk 86.
In the operating position of the actuating body 68 shown in
Fig. 6, the latter bears with the circumferential shoulder 11~
against the stop 114 of the housing 62, it thus being ensured that
the lip 100 bears precisely against the valve seat 70 when the
valve 66 is closed.
In Fig. 7, the actuating body 68 is shown, under conditions
enabling backflow, raised into the backflow position 68'. In this
position, the valve 66 is compulsorily opened and the flow path 60
as a result is connected to the venting path 58. By moving back
and forth, the actuating body 68 is slidingly and smoothly guided
from the operatlng position into the backflow position, and vice
versa, by means of the sliding bead 116 on the housing 62. Tilting
is thereby also prevented by the sealing member 104 in the form of
a diaphragm.
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Under normal operating conditions, the actuating body 68
is situated in the operating position shown in Fig. 6. The valve
66 is closed at all times and the nonreturn valve 118 is closed as
long as no water is flowing. With the control cartridge 32 open
(cf. Fig. 1), the water flows in the direction of flow S along the
flow path 60 through the flow passages 88 in the actuating body 68
and the flow bores 78, with the nonreturn valve 118 being held open,
to the outlet opening 80 where it is conveyed to the tube 42. The
tube 42 conducts the water to the hose 44 which guides it as far as
the hose sprayhead 12 from which it emerges at the outlet 52. The
venting path 58 is separated from the flow path 60 by the closed
valve 66. If, with the control cartridge 32 open, a low pressure
or vacuum is now set up in the supply line 34, it is possible for
water to be sucked from the outlet 52 counter to the direction of
flow S. Under these conditions enabling backflow, the nonreturn
valve 118 closes automatically, as a result of which water is
prevented from flowing back into the supply line 34.
Simultaneously, as a result of the low pressure or vacuum
existing on the supply side, the actuating body 68 is raised into
the backflow position 68' shown in Fig. 7, which causes the valve
66 to open compulsorily. As a result, the supply line 34 is
connected by the venting path 58 to the surrounding air. When
; fresh water is next conveyed in the direction of flow S, the
actuating body~68 is~moved back again into the operating position
:
by the pressure of the water, which causes the valve 66 to close
compulsorily.~ ~
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- 20 -
It is, of course, also conceivable for the nonreturn valve
118, which is inserted into the flow path and inserted downstream
in the direction of flow S from the opening of the venting path 58
into the flow path 60, to be designed differently. A ball valve is
thus also in particular conceivable.
Figures 8 and 9 show the safety device 36 shown in Figures 6
and 7 but where a throttle element 140 made from rubber-elastic
material and seated on the stem 96 has been provided instead of the
guard screen 102. The reference numerals in Figs. 8 and 9
correspond to those in Figures 6 and 7 and, as for the structure
and functioning of the safety device 36, reference should be made
to these figures and the corresponding description.
The annular throttle element 140 has a cross-section like that
of a bell so that it bears against the body part 84 on the side
facing the cavity 90 when there is no water flowing in the
direction of flow S and covers the flow passages on the body part
84 (Fig. 9). A through-hole 142 is provided in the throttle
element 140 which is aligned with one of the flow passages 88 and
has a narrower free cross~section than the corresponding flow
passage 88'. When water flows in the direction of flow S through
the flow passages 88, the throttle element 140 is deformed by the
downward pressure of the water, as shown in Fig. 8. It thereby
:
assumes the same guard function for the sealing lip 100 as the
guard screen 102 (Figs. 2,3,6,7).
~ The stem 96 has, on the side facing the body part 84 relative
to~the valve body 98,~a circumferential securing rib 144 in order
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2~2~8~
-21- 25561-67
to hold the valve body 98 securely between it and the rib 136" and
to clamp securely the throttle element 140 between it and the body
part 84. In the region of the throttle element 140 and the body
part 84, the stem 96 is cylindrical and it is secured in the
perforated disk 86 with its upper end region of a fin- or rib-like
design which engages in the blind hole 138.
Under normal conditions, the actuating body 68 is situated
in the operating position shown in Fig. 8, the sealing lip 100
bearing against the valve seat 70 in order to keep the valve 66
closed. With the control cartridge 32 open (Fig. 1), the watex flows
in the direction of flow S through the safety device 36, the
throttle element 140 being deformed into the position shown in Fig.
8 and the nonreturn valve 118 being opened. If the flow of water
is interrupted by closing the control cartridge 32, the throttle
element 140 b~ars automatically against the body part 84 and the
nonreturn valve 118 closes.
If a low pressure or vacuum is set up in the supply line
34, with the conl:rol cartridge 32 open, the nonreturn valve 118
closes, the throttle element 140 bears against the body part 84,
sealing all the flow passages 88 with the e~ception of flow passage
88', and the actuating body 68 is raised into the backflow position
68' as a result of the supply-side suction effect (Fig. 2). As a
result of this movement of the actuating body 68 into the backflow
position 68', the valve 66 is compulsorily opened. As a result of
the relatively small cross section of the through-hole 142 relative
to ehe cross-~e_tions of the venting path 58 and of the part of the
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2~2258~
- 22 -
flow path 60 situated downstream from the throttle element 140 as
seen in the direction of flow S, the force on the actuating body 68
for moving the same into the backflow position 68' becomes greater
than in an embodiment according to Figs. 2 to 7 with no throttle
element 140. ~ven with relatively small cross-sections of the
venting path 58 and the closed nonreturn valve 118, a very rapid
opening of the valve 66 is thereby achieved under conditions
enabling backflow. The supply-side low pressure is then eliminated
by air flowing through the flow path and the through-hole 142.
When water next flows in the direction of flow S, the
actuating body 68 is brought back into the operating position by
under pressure with water, which causes the valve 66 to close
compulsorily.
The restriction of the flow path 60 by the throttle element
140 also helps to prevent water from flowing back in the event that
the nonreturn valve 118 is defective. It can be seen that the
safety device 36 shown in Figures 2 and 3 can also be equipped with
a corresponding throttIe element.
It is, of course, also possible to provide several
through-holes, but the cross-section of all the through-holes taken
together should be smaller than the smallest flow cross-section of
the venting path 58.
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~2258~
- 23 -
The actuating member may, of course, have a design other than
that shown in the figures. In any case, it is situated in the flow
path and is pressured by the water. It may, for example, be
designed as a throttle element or as a resisting member and is
actively connected to the valve body.
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