Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Pressure Cap
Description
The present invention relates to a pressure cap for
openings in tanks, in particular motor-vehicle
radiators, according to the generic part of Claim 1.
In a pressure cap of this kind, which is known from DE
41 07 525 C1, the first and the second valve bodies are
concentrically nested in each other, whereby the second
valve body can be axially moved back and forth between
two end positions limited by a sealing seat or an
axially opposite sealing surface of the internal cap
component, and whereby in rest position the first valve
body is provided with spring-loaded support by the
second valve body which is supported by the internal cap
component. The sealing surface of the second valve body,
which is supported by the sealing seat of the interior
cap component, lies radially outside in relation to the
sealing seat of the second valve body which supports the
sealing surface of the first valve body. This results in
the following two-step operating state for the reduction
of overpressure: When a first threshold value of the
interior tank pressure is exceeded, the radially
exterior effective surface of the second valve body
causes it to be lifted off the sealing seat of the
interior cap component, which facilitates the reduction
of overpressure via a first flow connection. As the
second valve body is lifted off, the first valve body is
lifted as well against the effect of its first pressure
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spring. If the interior tank pressure continues to rise,
the second valve body is moved against the axially upper
sealing surface of the interior cap component, which
causes the first flow connection to close again, thus
preventing the liquid medium, such as a coolant, to
erupt. The second valve stage, which is represented by
the first valve body, affects the safety function of the
pressure cap in such a way that the first valve body is
lifted off the second valve body if the internal tank
pressure continues to rise and the safe threshold value
is exceeded, causing a second flow connection between
the interior and the exterior of the tank to open.
A disadvantage with this prior-art pressure cap is that
the sealing seats and sealing surfaces of the two valve
bodies and the interior cap component as well as the
axial path of the second valve body must be adapted to
each other with close tolerances. Furthermore, the
individual components must be of a relatively complex
design, which also applies to the installation of the
components. Furthermore, the hysteresis behaviour in
opening and closing of the flow connections) between
pressure rise and pressure fall is unsatisfactory.
Also known from DE 197 53 592 Al is a pressure cap of
the type named above, in which in rest position the
first valve body is directly contiguous to a sealing
seat of the interior cap component, and the second valve
body, which in rest position is pressed by a first
pressure spring of the first valve body against a second
pressure spring, is in the first valve step, after the
first threshold value of the interior tank pressure is
i
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exceeded, pressed against another axially opposite
sealing seat on the interior cap component when the
second threshold value is reached, whereby the first
valve body is lifted off its sealing seat on the
interior cap component. This determines the first flow
connection between the two valve seats on the interior
cap component on one side and the first or second valve
body on the other side, and it is closed first by the
first valve body and then by the second valve body. When
the point of safe overpressure is exceeded, the first
valve body is lifted axially by a thus affected vacuum
valve body which establishes the second flow connection
by lifting off the second valve body. In this case, it
is not as critical to adapt the individual components to
each other with close tolerances, but the design of the
interior cap component is somewhat more complex.
It is the objective of the present invention to create a
pressure cap of the type mentioned above, which is
simpler to manufacture and easier to install while it
has a better hysteresis behaviour.
This objective is achieved with a pressure cap of the
type mentioned above which has the characteristics named
in Claim I. _
With the measures according to the invention it can be
achieved that the tolerances required in manufacturing
the individual components and adapting them to each
other do not have to be as close, and that assembly can
be quicker. The hysteresis behaviour is improved as the
result of a throttle gap arranged ahead of the seal.
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Furthermore, the flow connection between the second and
third valve body is achieved primarily due to the
presence of liquid coolant and not because of a higher
gas pressure. In other words, when the interior tank
pressure is increased, the air cushion above the liquid
coolant can flow off and contribute to pressure
equalization until it is eliminated and the liquid
coolant is in place.
Advantageous embodiments of the configuration of the
third valve body in the second valve body result from
the characteristics named in one or more of Claims 2 to
5.
With the characteristics according to Claim 6 it is
achieved that the second valve body is pressed against
the sealing seat on the interior cap component by the
pressure existing in the chamber above the throttle gap
between the second and the third valve bodies.
Advantageous configurations of the individual sealing
seats in relation to each other result from the
characteristics named in one or more of Claims 7 to 9.
With the characteristics according to Claim 10 and/or
I1, an advantageous configuration of the vacuum valve
body in the pressure cap is achieved.
Also known from DE 197 32 885 A1 is a pressure cap with
a safety locking mans for openings in tanks. This
safety locking means makes it possible to prevent the
pressure cap being unscrewed when positive pressure
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prevails, namely by locking the pressure cap so that the
filler neck on the tank cannot be rotated. This prior-
art safety lock uses an axially movable insert which
- surrounds the interior cap component and/or its valve
assembly, and which is therefore directly exposed to the
positive pressure prevailing in the tank, since its
inner floor is arranged in the opening of the filler
neck. This axially movable insert is held in an
additional tubular interior component so that it is
axially movable while the pressure cap cannot be rotated
against it. When positive pressure occurs in the tank,
the insert is moved axially in the direction of the
pressure cap and engages in same but cannot be rotated.
This results in the anti-rotational locking of the
pressure cap via the insert and the additional interior
component with the filler neck of the tank.
The measures to be taken in accordance with that prior
art, to ensure anti-rotation and/or a safety lock, are
complex in terms of the design, and they require a large
number of components. Furthermore; the axially movable
insert as well as the additional tubular interior
component increase the diameter of the internal cap
component of the pressure cap or reduce the effective
surface of the valve arrangement of the pressure cap,
which has negative implications for the response
behaviour of the valve arrangement.
To remedy this situation, such a pressure cap is
provided with the characteristics according to Claim 12,
which means that its anti-rotation at positive pressure
can be ensured in a manner that is simple to design and
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to manufacture and is therefore more cost-effective to
produce. This is the case because thanks to the direct
deflection of movement from the first valve body, no
additional components are necessary, but instead, at
positive pressure, an idling connection is created
between the cap component comprising the thread or such
and the manipulating element or handling lid. This
idling connection within the exterior cap component at
positive pressure has the considerable advantage, in
comparison with locking the pressure cap at positive
pressure, that the activation of the anti-rotational
means becomes evident, thus eliminating the possibility
that force is used in case of a blockage.
Another space-saving feature for the valve arrangement
results when the characteristics in accordance with
Claim 13 are provided. The characteristics according to
Claim 14 are provided to support a return movement of
the coupling insert.
An advantageous embodiment of the coupling insert
results from the characteristics according to Claim 15.
It can be practical to provide suitable claw elements
having the characteristics in accordance with Claim 16.
In accordance with the characteristics of Claim 17, a
guide element. is provided for the direct transmission
of movement from the first valve body to the coupling
insert.
For the favourable control of the coupling insert even
at low positive pressure, it is provided to design the
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first valve body in two parts in accordance with the
characteristics of Claim 18. Embodiments of this are
based on the characteristics of one or more of Claims 19
to 21.
Further details of the invention are described below,
where the invention is described in with reference to
the embodiments shown in the drawings, where
Fig. 1 shows the partly longitudinal section of a
pressure cap for a motor-vehicle radiator,
with a positive-pressure / vacuum valve
arrangement in closed initial position, in
accordance with a first embodiment of the
present invention;
Fig. 2 shows the pressure cap according to Fig. 1 in
a position after the internal tank pressure
has exceeded a first threshold value;
Fig. 3 shows the pressure cap according to Fig. 1
after the internal tank pressure has exceeded
a second threshold value, or when dynamic
pressure prevails;
Fig. 4 shows the pressure cap according to Fig. 1
when the internal tank pressure has exceeded a
third safety threshold value; -
Fig. 5 shows the partly longitudinal section of a
pressure cap for a motor-vehicle radiator,
with a positive-pressure / vacuum valve
arrangement in closed initial position and
with an engaged anti-rotational means in
accordance with a second embodiment of the
present invention;
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Fig. 6 shows the pressure cap according to Fig. 5 in
a position at slight positive pressure inside
the tank and a disengaged anti-rotational
means;
Fig. 7 shows the pressure cap according to Fig. 1 in
a position after the interior tank pressure
has exceeded a first threshold value;
Fig. 8 shows the pressure cap according to Fig. 1
after the interior tank pressure has reached a
second threshold value or when dynamic
pressure prevails; and
Fig. 9 shows the pressure cap according to Fig. 5
when the interior tank pressure has exceeded a
third safety threshold value.
The pressure cap I1 for tanks such as motor-vehicle
radiators, shown in Fig. 1 to 4 in accordance with a
first embodiment, has an exterior cap component 13 which
is provided with a handling lid 12 and to which an
interior cap component 14 with a vacuum / positive-
pressure valve arrangement 15 is mounted. When in use,
the pressure cap II is fixed, for example screwed, to a
radiator neck (not shown). The interior cap component 14
extends inside the radiator neck toward the interior of
the radiator. -
An O ring 16 seals the interior cap component against
the wall of the radiator neck. The overpressure part of
the valve arrangement 15 is designed in two steps, and
it has the purpose of preventing the radiator from
boiling over in a first overpressure stage and
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protecting the radiator system against damage due to
excessive overpressure in a second overpressure stage.
Inside the interior cap component, the overpressure part
of the valve arrangement 15 has a first valve body 17
and a second valve body 18 as well as a third valve body
19.
The first valve body l7 is arranged in the direction of
the outside of the cap above the second valve body 18,
while the third valve body 19 is placed coaxially inside
the second valve body 18,
The first valve body 17 is designed in the farm of an
upside-down valve disk, the side of which facing the
inside of the radiator is provided with a ring seal 21
whose sealing surface faces axially inside. The first
valve body 17, at its side facing away from the inside
of the radiator, is compressed by a recoil spring 22
whose end facing away from the first valve body 17 is
supported by a spring plate 23, which in turn is
supported by the interior cap component 19. The first
valve body 17 is biased by the recoil spring 22 in the
direction of the inside of the radiator. Over seal 21,
which is designed as a flat ring seal, the first valve
body 17 bears on a first ring-shaped sealing seat 24 of
the second valve body 18.
The one-piece second valve body 18 has a hood element
26, whose free face is provided with the first sealing
seat 24, and a concentric hollow cylindrical receptacle
27 for the third valve body 19 pointing from the floor
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28 of the hood element 26 to the inside of the radiator.
Floor 28 between hood element 26 and receptacle 27 is
provided around its outer circumference with a flange
whose peripheral groove incorporates a second ring seal
in the form of an 0 ring 31. Added to this O ring 31 is
a second sealing seat 32 which is designed as a collar
rim on interior cap component 14. This collar rim 32 is
formed between an upper section of interior cap
component 14 (the hollow cylindrical section that has a
greater interior diameter and accommodates the first
valve body 17 and the hood element 26 of the second
valve body 18) and a lower section of interior cap
component 14 (the section that has a smaller interior
diameter and surrounds the receptacle 27 of the second
valve body 18) . On this lower section, the interior cap
component 14 is provided with an axial opening 33. By
means of recoil spring 22, the first ring seal 21 of
first valve body 17 is pressed against the first sealing
seat 24 of the second valve body 18, whose second ring
seal 31 in turn is pressed against interior cap
component 14. Between the underside of the first ring
seal 2I of the first valve body 17 and the upper side of
floor 28 of the second valve body 18 is a cylindrical
chamber 34 whose outer circumference in axial direction
between floor 28 and the underside of the first ring -
seal 21 is constant. In the middle, chamber 34 is in
communication with recess 37 in the second valve body 18
via a hole 35 in floor 28. At a cone-shaped section 38
at one free end of receptacle 27, recess 37 opens into
the axial opening 33 of the interior cap component 14,
Between hole 36 and recess 37, the second valve body 18
is provided with a shoulder which points toward the
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inside of the radiator and holds a third flat ring seal
39.
The third valve body 19, which can be designed for
example as a rotating element stepped in axial direction
around the periphery, is axially movable in recess 37 of
the second valve body 18. The third valve body 19 has a
neck section 41 of small diameter, which is movable
within hole 36 and inside the third ring seal 39, as
well as a shoulder section 42 whose slanted shoulder
area forms a third sealing seat 43 allocated to the
third ring seal 39 on the second valve body 18, and also
a cylindrical bulge section 44 which is supported in a
manner not shown in detail by the inner wall of cone-
shaped section 38 of the second valve body 18. For this
purpose, inside recess 37, a second pressure spring 46
is provided, one end of which is supported by the
underside of the third ring seal 39 of the second valve
body 18, while the other end is supported by a shoulder
between shoulder section 42 and the bulge section 44 of
the third valve body 19: The third valve body 19 is
biased toward the inside of the radiator by means of the
second pressure spring 46. Between the bulge section 44
of the third valve body 19 and the interior
circumference of recess 37 of the second valve body 18,
a very narrow annular gap is provided whose width is in
the magnitude of just a few hundredths of a millimeter.
This annular gap 47, as are hole 36 and chamber 34,
forms part of a first flow connection 50 between the
inside and the outside of the cap. A second flow
connection 51 bypasses the outer circumference of the
second valve body 18 (see Fig. 4).
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In the centre of the first valve body 17 is an opening
56 which on the side facing the inside of the radiator
is closed by a vacuum valve body 57 of valve arrangement
15. The main section 58 of this vacuum valve body 57
extends through the central opening 56. The end of the
main section is under pressure from a third pressure
spring 59, the one end of which is supported by a
shoulder of the main section 58 and the other end of
which is supported by the surface of valve body 17 that
faces the outside of the cap. In that manner, the
annular sealing seat 61 of vacuum valve body 57 seals
and is contiguous to the underside of the first ring
seal 21 of the first valve body 17. The sealing seat 61
of the vacuum valve body 57 lies radially inside the
first sealing seat 24 of the second valve body 18, while
the latter lies radially outside the second sealing seat
32 of the interior cap component 14, and the latter in
turn lies radially outside the third sealing seat 43 on
the third valve body 19. All sealing seats 24, 32, 43,
61 point axially outside, while all sealing surfaces 21,
31, 39 point axially inside.
In the initial operating position shown in Fig. 1, in
which a first threshold value of the inside tank
pressure is not yet exceeded, the first flow connection -
50 is closed by the sealing contiguity of the first
valve body I7 with its first ring seal 21 on the first
sealing seat 24 of the second valve body. In other
words, in chamber 34 and thus on the underside of the
first ring seal 41 of the first valve body 17, the
pressure prevailing inside the tank extends through
annular gap 47 in the form of the air cushion existing
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over the liquid coolant. The second flow connection 51
along the outer periphery of the second valve body 18 is
closed by the sealing contiguity of the second seal 31
of the second valve body 18 on the second sealing seat
32 of the interior cap component 14.
If the inside tank pressure rises above a predetermined
first threshold value, the pressure cap 1l reaches the
operating state shown in Fig. 2, in which due to the
increased inside tank pressure, the first valve body 17
is lifted against the effect of its first pressure
spring 22 with its first ring seal 21 from the first
sealing seat 24 of the second valve body 18, thus
opening the first flow connection 50, so that air can
flow outside from the air cushion over the liquid
coolant and- thus can compensate or reduce the
overpressure. Due to the overpressure in chamber 34, the
second valve body I8 with its second ring seal 31
continues to be pressed against the second sealing seat
32 of the interior cap component 14. If this causes the
overpressure to be reduced again below the first
threshold value, the first valve body 17 again seals and
is contiguous to the second valve body 18.
If on the other hand the inside tank pressure continues
to rise during or after the deflation of the air
cushion, and if this leads to a state where the liquid
coolant reaches the underside of the second and third
valve bodies 18, 19, the liquid coolant will accumulate
at the entrance of annular gap 47, due to the very
narrow width of the latter, thus causing the
accumulation of dynamic pressure on the full-surface
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underside of the third valve body 19. This dynamic
pressure results in an axial movement of the third valve
body 19 against the effect of its third pressure spring
59 at the end of which the third sealing seat 43 of the
third valve body 19 is contiguous to the third ring seal
39 of the second valve body 18, closing the first flow
connection 50 (see Fig. 3).
The closing of the first flow connection 50 between the
second and third valve bodies 18, 19 results in the
reduction of pressure in chamber 34 to below the above
named predetermined threshold value, so that the first
valve body 17 is moved toward the second valve body 18
by the effect of its first pressure spring 22. This
state is shown in Fig. 3 as well. If the inside tank
pressure is reduced because the radiator is cooling
down, and the liquid coolant is therefore returned, the
third valve body 19 is returned under the effect of its
second pressure spring 46, so that the first flaw
connection 50 in this section opens again, as shown in
Fig. 1
If, on the other hand, the inside tank pressure
continues to rise and exceeds an upper safety value, the
second valve body 18 is lifted (against the first -
pressure spring 22 that presses upon valve body 17) from
the second sealing seat 32 on the interior cap component
14, so that the second flow connection 51 is opened,
which allows the reduction of the said overpressure (see
Fig. 4). The lifting of the second valve body 18 from
the inside cap component 14 can be supported by an
additional (fourth) pressure spring 54 surrounding the
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receptacle 27. This fourth spring is supported at one
end by the underside of the floor 28 of the second valve
body 18 and at the other end by an inner shoulder of the
Lower section of the interior cap component 14 (drawn as
a dotted line in Fig. 4).
Valve arrangement 15 assumes the initial position shown
in Fig. 1 when the pressure inside the radiator varies
between a vacuum and a first overpressure value. Such
pressure conditions occur, for example, in a vehicle
that has been parked for some time, or when the coolant
inside the radiator of a moving vehicle is sufficiently
cooled by the outside wind stream and/or with support
from the fan. If, for example, the vehicle is parked
after a long drive, pressure may rise so much inside the
radiator that the valve arrangement 15 is supplied with
coolant (air, water or water vapour). If due to this
after-heating effect, the coolant volume expands so much
that it exceeds the tank volume, this would necessarily
result in the expulsion of coolant. As described above,
this undesirable effect can be prevented by valve
arrangement 15 assuming the operating state shown in
Fig. 2 and 3. If there is any further uncontrolled
pressure increase in the cooling system in that
operating state, the eruption of coolant and other
detrimental effects caused by excessive demands on the
radiator tank and/or the hose connections must be
prevented. Such effects can be prevented by the second
valve stage according to the state shown in Fig. 4,
which limits the tank pressure to a predetermined safety
value.
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If there is vacuum pressure inside the radiator, and if
this vacuum exceeds a predetermined vacuum threshold
value, the vacuum valve body 57 with its sealing seat 61
will be lifted - starting from the operational state
according to Fig. 1 - from the underside of the first
ring seal 21 of the first valve body 17 to the inside of
the radiator. The vacuum valve body 57 is lowered
against the bias of the third pressure spring 59, so
that a flow connection path will open (in a manner not
shown) between the inside and the outside of the
radiator.
The pressure cap 111 shown in Fig. 5 to 9 according to
another embodiment, for example for a motor vehicle
radiator, has an exterior cap component 113 provided
with a manipulating element or handling lid 112, from
which an interior cap component 114 with a vacuum /
overpressure valve arrangement 1I5 is suspended. When in
use, the pressure cap 111 is fixed, for example screwed,
to a radiator neck (not shown). The interior cap
component 114 extends inside the radiator neck toward
the interior of the radiator. An O ring 116 seals the
inferior cap component 114 against the wall of the
radiator neck.
In the case of the two-part exterior cap component 113,
the cap-like manipulating element or handling lid 112 is
axially fixed to the pressure cap element 113, here
designed as a screw cap element, but it can be rotated
in circumferential direction. This rotatability is
blocked when pressure inside the radiator is normal, by
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means of an axially movable coupling insert 180 for
screwing and unscrewing the pressure cap 111.
The overpressure part of the valve arrangement 115 is
formed in two steps and has the purpose of preventing
the radiator from boiling over in a first overpressure
stage, and of ensuring protection against damage to the
radiator system due to excessive overpressure in a
second overpressure stage. Inside the interior cap
component 114, the overpressure part of valve
arrangement 115 has a first valve body 117 and a second
valve body 118, as well as a third valve body 1I9. The
first valve body 117 is arranged in the direction of the
cap's outside above the second valve body 118, while the
third valve body 119 is accommodated coaxially inside
the second valve body 118.
The first valve body 117, designed in two parts, is
provided with a radially interior valve body part 165
roughly in the form of a valve disk, and a-radially
exterior valve body part 166; these overlap on the
edges, whereby the radially interior part sits on top of
the radially exterior valve body part. On the side of
the two valve body parts 165, 166 facing the inside of
the radiator, an annular membrane seal 121 is provided -
with sealing surfaces axially turned inward. The
radially exterior stepped valve body part ,166 of the
first valve body 117 is compressed by a recoil spring
122 on the side facing away from the inside of the
radiator. The end of this spring which faces away from
the first valve body 117 is supported by a valve disk
123 which in turn is supported by the interior cap
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component 114. By means of the recoil spring 122, the
radially exterior valve body part 166 of the first valve
body 117 is biased in the direction of the inside of the
radiator. Over the radially exterior flat sealing rim
168 of annular membrane seal I21, the radially exterior
valve body part 166 sits on a first annular sealing seat
124 of the second valve body 118. The radially interior
valve body part 165 of the first valve body 117 is
provided with a central recess 137 whose annular
limiting edge is surrounded by the interior part of
annular membrane seal 121. Toward the inside of the
radiator, this radially interior U-shaped sealing rim
167 of annular membrane seal 121 forms a sealing surface
for a vacuum valve 157 still to be described. On the
side of the outer edge, the radially interior valve body
part 165 bears directly on the inner edge of the
radially exterior valve body part 16& of the first valve
body 117.
The radially interior valve body part 165 is provided,
near its radial outer edge, with an axially projecting
annular edge 169 on which sits a guidance sleeve I71 the
inner end of which overlaps the annular edge 169
radially on the inside in offset fashion. Directly
bearing on the other axial end of the guidance sleeve -
171, which is formed by one-piece projecting fingers
172, is the coupling insert 180 under the effect of a
pressure spring 181 which is supported by the inside of
handling lid 112 of exterior cap component 113. The
coupling insert 180 is provided with a disk 185 in turn
provided with axially downward extending finger-like
claws 182 whose cross section corresponds to the fingers
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172 of guidance sleeve 171. As shown in Fig. 5, in s
state without pressure, the fingers 172 of guidance
sleeve 171 as well as the claws 182 of the coupling
insert 180 engage in axial recesses 173 of closure
element 110 of the exterior cap component 112.
Furthermore, axially toward the outside, i.e. facing
away from claws 182, the coupling insert disk 185 is
provided with projecting claws 183 which in positive
connection grasp between an axially aligned
circumferential serration 184 of handling lid 112. The
inward facing claws 182 are lying on a radially interior
ring, while the axially outward pointing claws 183 lie
on a radially exterior ring. In the initial or normal
position shown in Fig. 5, an anti-rotational connection
exists between the handling. lid 112 and the closure
element I10 of exterior cap component 113, so that the
pressure cap 111 can be screwed to and unscrewed from
the filler neck (not shown) of a tank.
The one-piece second valve body 118 is provided with a
hood element 126 whose free face is provided with the
first sealing seat 124, and a concentric and hollow
cylindrical receptacle 127 (pointing away from the floor
128 of hood element 126 and toward the inside of the
radiator) for the third valve body 119. The floor 128
between the hood element 126 and the receptacle 127 is
provided with a flange in whose circumferential groove a
second ring seal in the form of an 0 ring 131 is
incorporated. Added to 0 ring 131 is a second sealing
seat 132 which is designed as a collar rim on the
interior cap component 119. This collar rim 132 is
formed between an upper section of interior cap
s
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component 114 (the hollow cylindrical section that has a
greater interior diameter and accommodates the first
valve body 117 and the hood element 126 of the second
valve body 118) and a lower section of interior cap
component 114 (the section that has a smaller interior
20 diameter and surrounds the receptacle 127 of the second
valve body 118). On this lower section, the interior cap
component 114 is provided with an axial opening 133. By
means of recoil spring 122, the first ring seal 121 of
first valve body I7 is pressed against the first sealing
seat 24 of the second valve body 118, whose second ring
seal 131 in turn is pressed against interior cap
component 1I4.
Between the underside of the first annular membrane seal
121 of the first valve body 117 and the upper side of
floor 128 of the second valve body 118 is a cylindrical
chamber 134 whose outer circumference in axial direction
between floor 128 and the underside of the first annular
membrane seal 121 is constant. In the middle, chamber
134 is in communication with recess 137 in the second
valve body 118 via a hole 135 in floor 128. At a cone-
shaped section 138 at one free end of receptacle 127,
recess 137 opens into the axial opening 133 of the
interior cap component II4. Between hole 136 and recess
137, the second valve body 118 is provided with a
shoulder which points toward the inside of the radiator
and holds a third flat ring seal I39.
The third valve body 119, which can be designed for
example as a rotating element stepped in axial direction
around the periphery, is axially movable in recess 137
a
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of the second valve body 118. The third valve body 119
has a neck section I41 of small diameter, which is
movable within hole 136 and inside the third ring seal
139, as well as a shoulder section 142 whose slanted
shoulder area forms a third sealing seat 143 allocated
to the third ring seal 139 on the second valve body 118,
and also a cylindrical bulge section I44 which is
supported in a manner not shown in detail by the inner
wall of cone-shaped section 138 of the second valve body
118. For this purpose, inside recess 137, a second
pressure spring 146 is provided, one end of which is
supported by the underside of the third ring seal 139 of
the second valve body 118, while the other end is
supported by a shoulder between shoulder section 142 and
the bulge section 144 of the third valve body 119. The
third valve body 119 is biased toward the inside of the
'radiator by means of the second pressure spring 146.
Between the bulge section 144 of the third valve body
119 and the interior circumference of recess 137 of the
second valve body 118, a very narrow annular gap is
provided whose width is in the magnitude of just a few
hundredths of a millimeter. This annular gap 147, as are
hole 136 and chamber 34, forms part of a first flow
connection 150 between the inside and the outside of the
cap. A second flow connection 151 bypasses the outer
circumference of the second valve body 118 (see Fig. 9).
In the centre of the radially interior valve body part
165 of the first valve body 117 is an opening 156 which
on the side facing the inside of the radiator is closed
by a vacuum valve body 157 of valve arrangement 115. The
main section 158 of this vacuum valve body 157 extends
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through the central opening 156. The end of the main
section is under pressure from a third pressure spring
159, the one end of which is supported by a shoulder of
the main section 158 and the other end of which is
supported by the surface of valve body 117 that faces
the outside of the cap. In that manner, the annular
sealing seat 161 of vacuum valve body 157 seals and is
contiguous to the underside of the first annular
membrane seal 121 of the first valve body 117. The
sealing seat 161 of the vacuum valve body 157 lies
radially inside the first sealing seat 124 of the second
valve body 118, while the latter lies radially outside
the second sealing seat 132 of the interior cap
component 114, and the latter in turn lies radially
outside the third sealing seat 143 on the third valve
body 119. All sealing seats 124, 132, 143, 161 point
axially outside, while all sealing surfaces 121, 131,
139 point axially inside.
In the initial operating position shown in Fig. 5, in
which a first threshold value of the inside tank
pressure is not yet exceeded, the first flow connection
150 is closed by the sealing contiguity of the first
valve body 117 with its first annular membrane seal 121
on the first sealing seat 124 of the second valve body -
118. In other words, in chamber 134 and thus on the
underside of the first annular membrane seal 121 of the
first valve body 117, the pressure prevailing inside the
tank extends through annular gap 147 in the form of the
air cushion existing over the liquid coolant. The second
flow connection 151 along the outer periphery of the
second valve body 118 is closed by the sealing
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contiguity of the second seal 131 of the second valve
body 118 on the second sealing seat 132 of the interior
cap component 114.
If the inside tank pressure rises to a certain value
which lies above the normal or ambient pressure, but
below a first threshold value of the inside tank
pressure, the unscrew protection of pressure cap 111 is
activated. As shown in Fig. 6, the radially interior
valve body part 165 of the first valve body 117 is moved
upward, while the second valve body 118 remains in its
sealing position. Furthermore, the radially exterior
valve body part 166 of the first valve body 117 remains
in its sealing position in relation to the second valve
body 118. The annular membrane seal 121 allows this
relative movement between the radially interior valve
body part 165 and the radially exterior valve body part
166 due to the membrane seal's meandering shape between
its two sealing rims 167 and 168. The guidance sleeve
171, which sits on the radially interior valve body part
165 is moved along with said part toward the outside in
the direction indicated by arrow A. The said guidance
sleeve 171 in turn moves the coupling insert 180 against
the effect of pressure spring 181, and the guidance
sleeve's fingers 172 push the claws 183, which are
pointing axially inward, out of the recesses 183 in
closure element 110. This axial movement ends when the
inner shoulder of guidance sleeve 171 strikes ,against
closure element 110. The disengagement of the coupling
element 180 from the closure element 110 of exterior cap
component 112 has the effect that the handling lid 112
idles in relation to the closure element 110; so that
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starting at a certain predetermined overpressure (in
this case, for example, 0.3 bar), it is no longer
possible for the pressure cap I11 to unscrew from the
filler neck.
I0 If the inside tank pressure rises further, i.e. above
the predetermined first threshold value (for example 1.4
bar), the valve arrangement II5 reaches the operating
state shown in Fig. 7. Tn this state, due to the
increased inside tank pressure, the radially exterior
I5 sealing rim 168 of the radially exterior valve body part
166 of the first valve body 117 lifts off the first
sealing seat 124 of the second valve body I17 against
the effect of its first pressure spring 122, thus
opening the first flow connection 150 and allowing air
20 to flow outside from the air cushion above the liquid
coolant, thus compensating or reducing the overpressure.
Due to the overpressure in chamber 134, the second valve
body 118 with its second ring seal 131 continues to be
pressed against the second sealing seat 132 of the
25 interior cap component 114. If this causes the
overpressure to be reduced again below the first
threshold value, the radially exterior valve body part
166 again is contiguous to the second valve body 118.
The unscrew protection remains activated as before.
If on the other hand the inside tank pressure continues
to rise during or after the deflation of the air
cushion, and if this leads to a state where the liquid
coolant reaches the underside of the second and third
valve bodies 118, I19, the liquid coolant will
accumulate at the entrance of annular gap 147, due to
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the very narrow width of the latter, thus causing the
accumulation of dynamic pressure on the full-surface
underside of the third valve body 119. This dynamic
pressure results in an axial movement of the third valve
body 119 against the effect of its second pressure
spring 146 at the end of which the third sealing seat
143 of the third valve body I19 is contiguous to the
third ring seal 139 of the second valve body 118,
closing the first flow connection 150 (see Fig. 8).
The closing of the first flow connection 150 between the
second and third valve bodies I18, 119 results in the
reduction of pressure in chamber 134 to below the above
named predetermined threshold value, so that the
radially exterior first valve body 117 is moved toward
the second valve body 118 by the effect of its first
pressure spring 122. This state is shown in Fig. 8 as
well. If the inside tank pressure is reduced because the
radiator is cooling down, and the liquid coolant is
therefore returned, the third valve body 119 is returned
under the effect of its second pressure spring 146, so
that the first flow connection 150 in this section opens
again, as shown in Fig. 5.
If, on the other hand, the inside tank pressure
continues to rise and exceeds an upper safety value, the
second valve body 118 is lifted (against the first
pressure spring 122 that presses upon valve body 117)
from the second sealing seat 132 on the interior cap
component 114, so that the second flow connection 151 is
opened, which allows the reduction of the said
overpressure (see Fig. 9). The unscrew protection
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remains activated as before. Thus, the said overpressure
can be reduced via the second flow connection, after
which it is possible to return the valve bodies via the
various operating states through the individual pressure
springs and coupling insert 180, as shown in Fig. S. If
the lower claws 183 of the coupling insert 180 are
radially offset in relation to the recesses 173 in the
closure element 110, it is enough to turn the handling
lid 110 [sicJ to bring the claws 183 and the recesses
173 into alignment again, so that the compressed
1S pressure spring 181 brings the coupling element into he
non-activated position again opposite to the direction
indicated by arrow A.
Valve arrangement 115 assumes the initial position shown
in Fig. 5 when the pressure inside the radiator varies
between a vacuum and the first overpressure value. Such
pressure conditions occur, for example, in a vehicle
that has been parked for some time, or when the coolant
inside the radiator of a moving vehicle is sufficiently
cooled by the outside wind stream and/or with support
from the fan. If, for example, the vehicle is parked
after a long drive, pressure may rise so much inside the
radiator that the valve arrangement 115 is supplied with
coolant (air, water or water vapour). If due to this -
after-heating effect, the coolant volume expands so much
that it exceeds the tank volume, this would necessarily
result in the expulsion of coolant. As described above,
this undesirable effect can be prevented by valve
arrangement 115 assuming the operating state shown in
Fig. 6 to 8. If there is any further uncontrolled
pressure increase in the cooling system in that
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operating state, the eruption of coolant and other
detrimental effects caused by excessive demands on the
radiator tank and/or the hose connections must be
prevented. Such effects can be prevented by the second
valve stage according to the state shown in Fig. 9,
which limits the tank pressure to a predetermined safety
value.
If there is vacuum pressure inside the radiator, and if
this vacuum exceeds a predetermined vacuum threshold
value, the vacuum valve body 157 with its sealing seat
161 will be lifted - starting from the operational,
state according to Fig. 5 - from the underside of the
first annular membrane seal 121 of the first valve body
117 to the inside of the radiator. The vacuum valve body
157 is lowered against the bias of the-third pressure
spring 159, so that a flow connection path will open (in
a manner not shown) between the inside and the outside
of the radiator.
In a version (not shown) of one or-both of the above
embodiments, the sealing seat 61 or 161 of the vacuum
valve body 57, 157 is provided not on a level plate
arranged in a chamber 34, 134, but provided on a plate
whose cross section toward the outer periphery is
sawtooth-shaped and is arranged in a cylindrical. chamber
34, 134. Furthermore, in versions of one or both of the
said embodiments, the second sealing seat 32, 132 for 0
ring 31, 131 is designed as a conical surface.
In accordance with another version (not shown) of one
and/or the other embodiment of Fig. 1 to 4 or 5 to 9,
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the third valve body 19 or 119 is cup-shaped and able to
open toward the opening into the cylindrical chamber 34
or 134. The upper rim of this cup-shaped valve body
forms a ring seat for a sealing gasket which surrounds
the said opening into the cylindrical chamber 34, 134.
The cup-shaped third valve body accommodates a pressure
spring which corresponds to pressure spring 46, 146
which presses it down and away from the said sealing
gaket. The function of this third valve body remains the
same as that of the third valve body 19, 119 of the said
embodiments. In other words, when the ring seat of this
cup-shaped third valve body presses against the sealing
gasket, the respective flow connection is closed.
