Venting device

A venting device for sanitary conduits comprising a first edge 12 and a second edge 10 bounding an air passage 7. One side of a valve 8 of flexible material is retained on the upper side of first edge 12, the other side provided with a downwardly extending ledge 13 moveably engages the top 15 of second edge 10. The valve 8 is provided with a thinned portion 9 near the first edge 12.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a venting device for sanitary conduits 
comprising an air inlet and destined to prevent in buildings an escape of 
gases from a conduit for used water to the ambiance, and comprising a 
displaceable valve being able to abut sealingly against a seat, said seat 
being formed by a second and a first edge of an air passage between a 
conduit for used water and the ambiance. 
2. Description of the Prior Art 
An automatic venting device of this type for sanitary conduits adapted to 
discharge used water and destined in houses or buildings to cause on the 
one hand ambient air to flow into conduits at the event of an 
underpressure; and on the other hand to prevent the escape of contaminated 
air via the air inlet at the event of an overpressure or a regulated 
pressure in the conduits, is known from German Offenlegungsschrift No. 28 
38 111 and No. 28 38 068. 
Said known automatic venting device exhibits the disadvantage that the seal 
of the displaceable valve upon the seat is often rather inappropriate so 
that evil smelling gases may easily escape to the outside from the 
discharge conduits for used water. This inconvenience gets the worse in 
that pollutions such as dust particles, may contaminate the edge of the 
air inlet, engaging the displaceable valve, thus causing an insufficient 
seal between said edge and the displaceable valve, in the course of time. 
On the other hand, said valve cannot be removed from the seat in a 
sufficiently rapid manner at the event of an underpressure in the conduit 
for the discharge of used water, so that the known disadvantage of noise 
cannot sufficiently be obviated at the occurence of an underpressure in 
the discharge conduit. 
SUMMARY OF THE INVENTION 
It is a primary object of the present invention to provide an improved 
automatic venting device of the abovementioned type, which does not suffer 
from these disadvantages. 
This object is attained according to the invention in that the valve of 
flexible material is retained upon a first edge and the freely moveable 
other side of the valve is able to adjoin the second edge sealingly. 
When employing a valve of the above construction the aforementioned 
disadvantages will not occur while, moreover, the flexible valve will move 
over the top of the second edge at the occurence of an overpressure in the 
conduit, so that dust particles, if any, will be removed. 
It has been found that at the event of an underpressure in the conduit, the 
use of a valve fixed in this manner, will provide an optimum venting 
without any evil smelling gases escaping at the event of an overpressure 
in the conduit. 
The valve is very advantageously provided with a thinned portion, so that 
on the one hand a relatively thick valve to obtain a very good seal can be 
used which valve has on the other hand an optimum flexibility, thus being 
able to adjoin the second edge to obtain an optimum seal. 
The presence of the thinned portion also improves the flexibility of the 
valve so that an easy displacement over the top of the second edge can be 
effected at the event of an overpressure and the said top can be kept 
perfectly clean without the presence of any contaminations or dust 
particles. 
The valve is advantageously fixed upon an edge by means of a fixing member, 
so that the valve can be fixed in the automatic venting device in a very 
cheap manner. 
The freely moveable edge part of the valve is preferably provided with a 
member bounding a displacement of the valve so that, at the occurence of 
an extremely great overpressure in the conduit, said valve cannot be 
displaced over the top of the second edge thus causing the entire sealing 
of the venting device to get lost, notwithstanding the very good 
flexibility of the valve due to the presence of the thinned portion. 
The member bounding the displacement of the valve very advantageously 
consists of a ledge directed towards the inside of the second edge. 
The valve preferably consists of flexible material, such as a natural or a 
synthetic rubber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a syphon consisting of a cylindrical body comprising a first 
and a second cylindrical part 1.sup.1, 1.sup.2, being mutually connected 
at point 2 by screws and connected to the main through a pipe 3. Parts 
1.sup.1 and 1.sup.2 consist of plastics. 
A pipe 4 connected to a sink or wash-stand 5 of the like projects from the 
cylindrical body. A water lock 6 prevents the escape of evil smelling 
gases from the conduit for used water. 
The top end of the device comprises an annular air passage 7 being on the 
one hand bounded by a cylindrical second edge 10 embracing an inner wall 
14 and an upper surface 15. 
On the other hand the air passage is bounded by a cover 16 comprising an 
annular skirt 16a. 
A circumferential edge of a flexible valve 8 of rubber is fixed between the 
inner side 17 of the cover 16 and the top 11 of a first edge 12 being 
integral with the first part 1.sup.1. 
In FIG. 1 said valve 8 allows the air passage 7 to be open whilst FIG. 2 
shows the situation of an overpressure prevailing in the inner side of 
conduit 3, so that valve 8 is pressed sealingly upon upper surface 15 of 
the second edge 10 while deforming valve 8 of deformable material. An 
optimum seal of valve 8 is obtained by a thinned portion 9 provided in the 
area adjacent the edge portion of valve 8, and clamped between the top 11 
of the first edge 12 and the inner side 17 of cover 16. 
This thinned portion 9 preferably extending over the entire circumference 
provides an optimum seal of the valve 8. 
To prevent the outer edge of the displaceable part of valve 8 to be pressed 
over the top 15 of edge 10 at the event of a too great overpressure in 
conduit 3, the freely displaceable edge part of the valve comprises member 
13 in the form of an annular ledge for bounding a valve displacement, 
which ledge is integral with the valve. 
Due to the use of said shoulder 13 directed towards the inner side 14 of 
the second cylindrical edge 10, the edge part of valve 8 cannot possibly 
be pressed over the top of the second edge 10 at the event of very high 
overpressures in conduit 3, so that an optimum seal is maintained. 
In order to obtain a good engagement of valve 8 and top 15 of the second 
edge 10, the top 15 of the second edge 10 preferably has a rounded shape. 
Said rounded shape even prevents noise in the case that ambient air flows 
inwardly along the second edge 10, which noise would be audible when said 
top side 15 would have a non-rounded shape. 
Valve 8 is preferably slopingly postured whilst the clamped edge portion 
and the top side 15 of the second edge have a normal position. Drops of 
water falling upon the valve will therefore easily disappear, due to the 
inclined position of valve 8. 
The openings between the lands 18 of the air passage 7 are advantageously 
closed by a filter, e.g. for insects. 
FIG. 3 shows a vertical pipe 19 connected to a venting channel (not shown), 
its upper end provided with a Venturi-shaped narrowing consisting of a 
truncated conical collar 20, terminating in a second edge 10 and 
co-operating with a cover 21 through a first edge 12 in such a manner, 
that the annular air inlet 7 extending along the circumference is formed. 
Said annular air inlet extending along the circumference can be sealed off 
by an annular valve 8 which is being retained upon the top side 11 of the 
first edge 11. The remaining reference numerals are the same as in FIG. 1.