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 wall feedthrough
fitting. More particularly this invention concerns a fitting
which is cast into or subsequently fitted through a wall so that
electrical wires, pipes, and the like can pass through the wall
at the fitting.
Back~round of the Invention
In Canadian Patent No. 1,041,028 issued on October
24, 1978, there is disclosed a wall duct assembly comprising a
duct having on its outer surface retaining grooves in which are
provided seals. These seals can be axially compressed so that
when the unit is cast into a wall axial compression of the seals
forces them radially outwardly against the wall, radially
inwardly against the tube, and axially in one direction also
against the wall, thereby forming an excellent seal.
Such an arrangement has, however, the disadvantage
that two seals must be used, so that the construction costs are
somewhat elevated. Furthermore the device is frequently fouled
when the cable, pipe, or the like is pRssed through the duct, as
the inner surface of the seal is exposed when the cover or end
piece for the unit has been removed.
Objects of the Invention
It is therefore an object of the present invention to
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provide an improved wall feedthrough fltting.
Another object is to advance the principles set forth
in the above-mentioned copending application and improve thereon.
A further object is to provide such a wall feedthrough
fitting which is relatively simple to manufacture so that it can
be produced at relatively low cost, and which forms an excellent
tight seal.
Finally an object of the instant invention is to pro-
vide a wall fitting where the compressible seal part is protect-
ed from fouling when the end cap has been removed.
Summary of the Invention
These objects are attained according to the present in-
vention in a wall feedthrough fitting wherein an annular seal
surrounds a feedthrough tube whose opposite axial ends are each
exposed at a respective face of a wall in which the tube is em-
bedded. A holding ring surrounds the tube at the seal and radi-
ally engages the seal. This holding ring extends axially in one
direction beyond the seal toward one end of the feedthrough tube
and has between the seal and this one end an internal screw-
thread. A pressure ring is provided between the holding ring
and the tube, and is threaded into the screwthread of the hold-
ing ring so that it can bear axially in the opposite direction
on the seal. Thus screwing of the pressure ring into the hold-
ing ring presses the seal axially in this opposite axial direc-
tion.
With the fitting according to the instant invention
the seal ring itself is not exposed radially inwardly. Thus
the insertion of cable, pipe, or the like through the fitting
will not foul the seal. What is more, the single seal ring
serves for a complete sealing of the fitting with respect to
the wall around.
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According to this invention the pressure ring which is
threaded into the holding ring may itself bear directly axially
on the seal. This can advantageously be accomplished by forming
the one end of the tube of the fitting with an external thread
that meshes with the corresponding and complementary thread on
the pressure ring. This particular arrangement has considerable
advantages during installation of the fitting, in particular when
cast into a wall. The one~piece pressure ring is screwed into
place so as to lock the relative positions of the holding ring,
the seal and the feedthrough tube. Tightening of the pressure
ring after the wall is hardened around the unit tightens the
seal as described above. It is also possible after hardening of
the wall around the unit to withdraw the one-piece pressure ring
and replace it with various other units.
This last-mentioned possibility is particularly advan-
tageous when the user desires to provide an extension or nipple
one one side of the fitting. This extension can be constituted
as a tube or intermediate ring which has one axial face directed
in one axial direction and bearing directly on the pressure ring
2~ and another axial face directed in the opposite direction and
bearing on the seal. To this end the pressure ring is substan-
tially of L-section and has one L-leg extending axially and
formed with an external screwthread engaging the internal screw-
thread and another L-leg projectin~ radially inwardly from the
one L-leg and bearing directly axially in the opposite direction
on the intermediate ring. This intermediate ring may have a t~
bular portion extending axially in the one direction. The ad-
vantage of such an arrangement is the intermediate ring need
not be rotated to tighten the seal, instead the pressure ring
is rotated to press the intermediate ring into tight contact
with the seal, so that in effect the seal is formed with this
intermediate ring. ~onetheless the offset inner portion of the
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intermediate ring ensures that cables~ pipes, or the like passed
through it will not come into direct contact with the seal and
dirty it.
The feedthrough tube may in accordance with another
feature of this invention be constituted as the insulating lin-
ing sleeve surrounding a ground connector as described in the a-
bove-cited copending application. Thus fitted within this insu-
lating feedthrough sleeve is a bar of conductive material having
its ends exposed at the opposite faces of the walls and each
formed with a blind bore. Terminal screws threadable into this
blind bore allow an electrical connection to be made through the
wall, with virtually no possibility of leakage through the wall
at the connection.
Brief Description of the Drawinq
FIG. 1 is an axial partial section through a fitting
according to this invention;
FIG. 2 is a similar section through another fitting in
accordance with the present invention;
FIGS. 3 and 4 are axial partial sections through inter- -
mediate rings according to the instant invention; and
FIG. 5 is an axial section through a completely instal-
led fitting in accordance with the present invention.
Specific Descr ption
As shown in FIG. 1 a feedthrough tube 1 centered on an
axis A is formed with an annular outwardly concave seat 33 re-
ceiving an elastomeric 0-ring 3 dimensioned to snugly radially
inwardly bear on the tube 1 at the seat 33. Radially outside
the tube 1 is provided a holding ring 4 formed with an inwardly
concave seat 34 against which the seal 3 bears radially outward-
ly. The tube 1 and holding ring 4 are both made of a metal and
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are separate pieces movable relative to each other both radially
and axially. A space 5 open axially in both directions is de-
fined between the tube 1 and holding ring 4. Furthermore the
ring 4 has an axial extension or collar 6 formed with an inter-
nal screwthread 10. An L-section pressure ring 8 has an axially
extending leg formed with an external thread 9 that engages the
thread 10 and a radially inwardly extending leg 13 forming an
axial pusher face 12 and also formed with recesses 15 adapted to
be engaged by a wrench.
Between the pressure ring 8 and the tube 1 there is
formed a space 7 in which i~ received an intermediate or pusher
ring 11 forming a pusher surface 2 bearing axially on the por-
tion of the seal 3 exposed in the space 5 between the ring 4 and
the fitting 1. This intermediate ring 11 has a radially inward-
ly extending flange 14 that bears axially on the face 12 of the
leg 13 of the pressure ring 8. The pressure ring 8 is formed
with a radially inwardly projecting ridge 3~ engaging in a radi-
ally outwardly open annular recess 3Ç formed in the intermediate
ring 11 so that the two parts 8 and 11 are axially linked togeth-
2~ er but relatively rotatable and forcibly seaprable. In addition
the face or shoulder ~ of the intermediate ring 11 has an axial-
ly projecting bump 37 that axially bears on the seal 3.
The intermediate ring 11 having the flange 14 is actu-
ally merely the end part of an extension tube 17 having an end
16 adapted to fit a conduit or the like. This end 16 may be
formed with several holes dimensioned ro receive respective
pipes, conduits, or wires. It is also possible to merely ter-
minate the flange 14 as shown in FIG. 3 to leave a large-diame-
ter throughgoging hole 18. Furthermore as shown in FIG, 4 the
flange 14 can be extended across to form a closed end 16a that
may be drilled after installation as desired, or simply used to
close off the fitting if not needed or until needed.
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With the arrangement of the instant invention it is
possible to install the device to start with by providing a cap
32 at each end, and by employing a one-piece pressure ring 8a
having an internal thread 19 matching an external thread 38 as
shown in FIG. 2. This one-piece pressure ring 8a therefore has
on its outer periphery the screwthread 9 and on its inner peri-
phery the screwthread 19, both of identical hand and pitch.
The ring 8a is screwed into the assembly to hold it in the pro-
per position during casting of a wall around the device, with
the caps 32 preventing entry of the casting material, normally
concrete, into the fitting. Once the concrete is hardened the
one-piece ring 8a is withdrawn and can be replaced with the
arrangement sh~wn in FIG. 1.
After installation rotation of the ring ~ or 8a by
fitting an appropriate tool into the recess 15 will force the
shoulder surface 2 axially against the seal 3 and thereby press
it into excellent contact with the seats 33 and 34 and also into
contact with the concrete of the wall exposed between these
seats 33 and 34. Counter shoulders 31 and 31' formed by flanges
30 and 30' on the tube 1 and ring 4, respectively, prevent axial
shifting of these parts within the wall once it has hardened and
cured.
FIG. 5 shows how a tube la of insulating material may
receive internally a metal bar 20 secured in place by a trans-
verse pin 21 and having its opposite ends formed with threaded
blind bores 22 as described in the above-cited Canadian patent.
This arrangement is embedded in a wall 23 with the flanges 30a
forming the counter shoulder 31a at one face of the wall and
the seal arrangement at the op~osite face. During casting of
the wall plugs 24 are screwed into the bores 22 to prevent con-
crete or the like from entering them, but after instaliation
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terminal screws 25 having locknuts 26 can be screwed into these
bores 22 to form the electrical connection through the wall 23.
The one terminal screw 25 may have an extension 27 that is con-
nected to a ground rod, and the other screw 25 may be connected
to an eye 28 on the end of a ground cable.
At its end opposite the flange 30a there is provided a
holding ring 4, seal 3, and pressure ring 8a identical to Lhose
described in FIG. 2, In this arrangement after installation the
one-piece pressure ring 8a need merely be screwed in somewhat
tighter on the threads 38 and 10 of the tube la and holding ring
4 as described above to increase the sealing effect.
With the system according to the instant invention the
single seal 3 ensures that no leakage around the tube 1 will be
possible. This ring 3 can be tightened after installation of
the assembly, but at the same time is not exposed inside the
tube 1 so that fouling of this seal 3 during insertion of cables,
pipes, or the like through the tube 1 is almost impossible.
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