Note: Descriptions are shown in the official language in which they were submitted.
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My present invention relates to a trap for a drain, designed to
oonduct waste water from a sump, gully or the like to a sewer.
In such a trap, especially one installed in a basement or some
other part of a dwelling, it is desirable to provide mEans for not only
blocking the escape of sewer gases but also preventing a backup of water
from the sewer to the trap. Under severe overflow conditions, as where
a sewer is flooded in a downpour, it is desirable to rely for this purpose
on a shutter more effective than a simple check valve to stop the flow. A -
trap with a dual seal, i.e. a check valve in the form of a ball float and
a shutter closable by a handwheel, is known for example from German utility
mDdel No. 1,917,289. Such a construction, however, is relatively cumber-
some and requires an enlargement of the drain in comparison with more
; usual traps. Even so, the handwheel crowded by the float valve is not
easily accessible and is difficult to operate.
The object of my present invention, therefOre~ is to provide an
improved anti-backup trap including a manually closable valve which is of
compact construction and can be fitted to a normal drain without major
alterations.
My invention is an anti-backup trap for a drain, comprising: an
upwardly open housing having a sidewall provided with an exit port for
entering waste water; a tubular insert in said housing ad~acent said sidewall,
said insert having a bottom inlet beneath the level of said exit port and
a side outlet registering with said exit port; a flap hinged to said insert
for outward swing mg to facilitate the outflow of water, said flap forming a
check valve to prevent the return of water from said exit port to said housing;
and manually operable shutter neans in said insert inteLposed between said
inlet and said outlet, said shutter means being accessible thr~ugh the top
of said housing; said insert being provided with an apertured partition
curved about a substantially horizontal axis, said outlet being substantially
centered on said axis, said shutter means comprising a tubular valve body
with a peripheral wall conforming to the curvature of said partition, said
body resting on said ~artition ~or rotation about said axis and having a
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peripheral opening alignable with an aperture of said partition in an
unblocking position.
I realize this object, in accordance with my present invention,
by providing a tubular insert adjacent a sidewall of an upwardly open
housing, this insert having a lateral outlet registering with an exit port
in that sidewall and further having a bottom inlet beneath the level of
that port. A flap hinged to the insert for outward swinging forms a check
- valve which facilitates the outflow of water from the housing but prevents
any return flow from the exit port. The insert also contains a manually
operable shutter mechanism interposed between its inlet and its outlet, the
shutter merhanism being accessible through the top of the housing upon the
removal of a lid normally overlying that top.
The shutter mechanism of my improved anti-backup trap includes
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an apertured partition within the insert and a coacting valve member located
either below or above that partition. In one embodiment, the partition is
curved about a substantially horizontal axis at the center of the outlet,
the valve member having a tubular body with a peripheral wall which conforms
to the curvature of the partition and rotatably rests thereon whereby a
peripheral opening in that body can be aligned with the partition aperture
in arl unblocking position and can be disaligned therefrom in a blocking
position. In another embodiment the valve body is a horizontal disk which
is vertically displaceable between a blocking and an unblocking position
with the aid of a handwheel through the intermediary of a leadscrew coupling.
The above and other features of my invention will now be described
in detail with reference to the accompanying drawing in which:
; Figure 1 is a longitudinal sectional view of an anti-hackup trap
embodying my invention;
Figure 2 is a similar view, drawn to a larger scale, of an
insert forming part of the trap of Figure l;
Figure 3 is a view similar to Figure 2, showing another embodi-
ment; and
Figure 4 is a top view of the housing of the trap shown in
Figure 1.
` As illustrated in Figures 1 and 4~ a trap according to my
;~ invention comprises a housing 10 of rectangular outline whose open top
forms a peripheral rabbet 2 for the seating of a removable lid 3. The
left-hand half of the lid is provided with a multiplicity of perforations
30 through which rainwater or other liquid wastes may enter the housing 10.
&e right-hand half of the lid 3 has a countersunk grip 4 to facilitate
its removal from the housing. Also illustrated in Figure 1 is a lateral
entrance port 1 through which waste water collected elsewhere, e.g. in a
` kitchen sink, can pass into the trap housing. A nipple 13 on the opposite
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sidewall of the housing, forming an exit port, is tilted slightly down-
wardly for connection to a nonillustrated sewer pipe. It will be noted
that both parts 1 and 13 lie in the upper half of housing 10.
A tubular insert 11 is molded or deep-drawn from a tough and
corrosion-resistant plastic material, such as polyester, from which the
housing 10 and its lid 3 may also be formed in like manner. Insert 11 is
removably seated in the housing 10 adjacent its right-hand sidewall provided
with the exit port 13. This insert, more fully illustrated in Figure 2,
comprises essentially a downwardly open conduit 22 forming a depending
skirt around a bottGm inlet 31; an outlet 32 on the side of the conduit
registers with exit port 13 and is centered on a horizontal axis A. An
upwardly concave partition 16 integral with conduit 22, centered on axis
A, has an elongate aperture 21 extending over the greater part of its
axial length. Partition 16 forms with the complementarily curved top 161
of conduit 22 a frustoconical shell tightly embracing a hollow frustoconical
valve body 17 coaxial therewith. Valve body 17, made of the same resinous
material as conduit 22, has an opening 20 which is similar to aperture 21
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and registers therewith in a normal unblocking position as illustrated in
solid lines in Figure 2. In an alternate blocking position, illustrated
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in dot-dash lines, aperture 21 is closed.
Conduit 22 forms an integral flange 12 around the outlet 32
which is defined by the broader end of the stationary frustoconical shell
16, 16~. A circular groove 34 in this flange accommodates a packing ring
36 to form a fluidtight seal with the confronting sidewall of housing 10.
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The broad end of valve body 17, open toward exit port 13, projects slightly
beyond flange 12 and forms an annular seat ~6 for a circular flap 25 acting
, as a check valve. Flap 25 has an arm 37 which is hinged at 38 to a lug 24
`~ firmly held in a recess 23 of flange 12. Hinge 38 lies directly above the
i seat 26 so that the flap 25, in the absence of countervailing fluid pressure,
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retur.ns under its own weight to its illustrated closure position in which
a convex face thereof comes to rest against that seat. As the entering
water rises within tube 22 above partition 16, the flap 25 is thrust aside
and swings outwardly into the exit port 13 to let the water escape into
the adjoining drain pipe.
The smaller, closed end of valve body 17 has a boss 17' journaled
in the opposite wall of corduit 22, this boss terminating in a square head
18 to which a handle 19 is removably fastened with the aid of a cotter pin
28. Handle 19, as shown in Figure 1, can be easily reached upon the removal
.~ 10 of lid 3 and can be swung through about 90 to establish either the un-
- blocking or the blocking position of valve body 17. In either position
the handle will include an angle of about 45 with the vertical; markings
27 (only one shown in Figure 2) may be provided on the outside of insert
11 to indicate the open or the closed state of the valve. ~ -
` The right-hand sidewall of housing 10 is formed with an upwardly
open pocket 15 baunded by a lip 39 which enters a pair of corresponding
notches 40 (only one shcw.n) in the bottom edge of conduit 22 to insure a
proper seating of insert 11 in the housing; a flat foot 14, separated by
the notches 40 from a cylindrical part of the skirt surrounding its inlet
: 20 opening 31, fits from above into pocket 15. The mDunting of the insert 11
is completed with the aid of bolts 35 projecting inwardly from the right-
hand housing wall on opposite sides of recess 23 (see also Figure 4) and ..
passing through nonillustrated lateral holes of flange 12. Reference is
si. made in this connection to my Canadian patent 1,044,111. .
As further shown in Figure 1, and as also disclosed in these
:; cDpending applications, the left-hand half of housing 10 underneath the
. perforated section of lid 3 may hold a removable filter screen, in the form
; of a basket 5 with handle 5a, designed to catch solid objects such as
pebbles dropping thrcugh the lid into the housing.
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The water level inside the housing is normally defined by the
lower edge of outlet 32, except upon closure of shut-off val~e 16, 17~ in
which case that level may go higher.
In figure 3 I have shown an alternate insert 111, comprising a
~_J ~ conduit 122 of a shape generally similar to that of conduit 22, forming
again a bottom inlet 131 and a lateral outlet 132 closable by a flap 125.
A partition 116, disposed horizontally between the inlet and the outlet, has -~
a circular aperture 121 bounded by a depending rim 1211 which constitutes
a seat for a valve body 117 in the shape of a horizontal disk. Partition
116, integral with the tubular housing wall 122, lies just below the level
of outlet 132. Underneath that partition, conduit 122 has a set of vertical
ribs 122~ which enter into peripheral notches of disk 117 and hold it
against rotation. The disk, whose diameter is substantially less than the
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width of conduit 122, is rigid with a vertical leadscrew 118 which is
threadedly engaged by a nut 119 rotatably journaled in the top wall of the
conduit. Nut 119 terminates in a handwheel ll9a~ accessible upon removal
of lid 3 (Figure 1), whose rotation raises the disk 117 from its illustrated
unblocking position into a blocking position on seat 121l. A depending
stem 118l, forming a downward extension of leadscrew 118, limits the down-
ward stroke of the disk by coming to rest on the bottom of housing 10.
In both inserts 11 and 111 the water entering from the bottom
can normally reach the outlet via a flow path whose cross-section is at
least equal to that of the outlet. The skirt formed by the conduit 22 or
122 below the normal water level should be high enough to prevent the
escape of sewer gases into the housing, that height being preferably not
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less than the diameter of outlet 32 or 132.
` As illustrated in Figures 1 and 4~ the rim of the housing sur-
rounding its inner rabbet 2 is provided with an outer peripheral flange
33 facilitating the clamping of that housing to an upward extension as
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described in my concurrently filed Canadian application Serial No. 253,579
filed May 28, 1976.
m e easy detachability of handle 19 simplifies the cleaning of
insert 11, upon its re~.oval from housing 10, since it is merely necessary
for that purpose to extract the valve body 17 by its broader end from the
shell 16, 16~. Even without such removal, the relative rotation of these
two valve members with the aid of handle 19 has a cleansing effect and
Impedes the accum~lation of grit between their coacting surfaces.
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