Drain fitting with built-in pump

A drain fitting has a vessel formed with a laterally open housing outlet, at least one inlet, and an internal seat at the outlet. A pump is provided in the vessel and has a pump housing secured to the seat and having a pump output extending into the outlet and a pump intake, an impeller displaceable to move liquid through the housing from the intake to the output, and a motor in the housing driving the impeller. A check valve is provided in the pump output for preventing liquid flow back into the pump housing as well as means releasably securing the pump on the seat in the vessel. The pump housing is substantially closed and has its intake substantially lower than its output so that it acts as a gas trap.

FIELD OF THE INVENTION 
The present invention relates to a drain fitting. More particularly this 
invention concerns a drain fitting used when the liquid level in the drain 
occasionally is higher than the drain outlet. 
BACKGROUND OF THE INVENTION 
Normally no matter how many soil and rain stacks a building has, there is 
only one connection--the so-called sewer service line--to the sewer main 
that runs under the street. The sewer service line itself runs as a rule 
at a slight incline, of at least 3.degree., from the building down to the 
sewer main. In many areas, particularly ones where the sewers were laid 
down a long time ago, the sewer main is not very deep. As a result when 
the sewer system is heavily loaded, either by a heavy rain or simply by 
many users employing a line intended for lighter use, the effective liquid 
level in the sewer can be higher than that of the in-house drain, that is 
the sewer main can be completely full whereas it is normally only intended 
to run partially full. In such situations sewage can back up through the 
service line into the house drain and thence into the basement with the 
obvious unpleasant results. 
It is possible to protect against the worst effects of such a situation by 
the simple expedient of putting a backflow preventer or check valve in the 
sewer service line. Thus no sewage from outside can back up through the 
drain into the basement. Nonetheless since there is considerable back 
pressure holding the check valve closed, any waste descending the in-house 
waste lines will not be able to exit, and will simply rise up out of the 
lowermost drains in the building, creating on a small scale the same 
problem as with no check valve. 
The disadvantages of the above-described arrangement can be overcome by a 
system wherein the building drain is not connected directly to the service 
line, but to the intake of a pump whose output is connected to an elevated 
sump or storage vessel itself connected via a service line to the sewer 
main. The storage facility itself is provided at a level which is much 
higher than than the highest possible liquid level in the sewer main, so 
that sewage cannot possibly flow back through the storage vessel. Thus 
waste is pumped uphill by this pump to the elevated storage facility and 
then flows by gravity down into the sewer main. With such a system the 
pump must lift all waste, even when the liquid level in the sewer main is 
below that in the building drain, since the path to the sewer main has a 
high point over which the waste must be pumped. Obviously such a system 
uses a considerable amount of energy to operate the pump, and requires 
that a very heavy-duty pump be used. Furthermore any failure of the pump 
will result, whether or not the drain liquid level is above or below the 
level in the building drain, in a backup of waste in the building. 
It has also been suggested in German patent document 1,057,984 to provide a 
collecting sump in the building drain having a weir subdividing this sump 
into an upstream portion into which liquid waste flows from the building 
and a downstream portion connected via the sewer service line to the sewer 
main. A check valve is provided in the sewer service line. A float 
arrangement provided in the downstream portion of the collecting sump is 
actuated when liquid level in the downstream portion exceeds a 
predetermined level, as occurs when the sewer liquid level rises to close 
the check valve and sewage cannot flow out of the downstream portion. A 
pump is connected between this downstream portion and a bypass conduit in 
turn connected to the service line downstream of its check valve and is 
operated by this float arrangement to pump the waste via the bypass 
conduit into the service line in the event of a backup, as the pump is 
capable of generating sufficient pressure to overcome the back pressure in 
the line. 
This system has the considerable advantage that the pump only operates when 
the effective liquid level in the sewer main is dangerously high. As a 
result no energy is used under normal circumstances. Furthermore it is 
possible to employ a relatively light-duty pump, as compared to the 
continuous-duty pump needed in the other above-described pump system, as 
the pump only operates periodically and need only be able to move the 
waste from a single building. Still this arrangement requires considerable 
extra plumbing, and normally excavation of the sewer service line in order 
to install it in an existing drain system. Thus the first costs are quite 
high. 
OBJECTS OF THE INVENTION 
It is therefore an object of the present invention to provide an improved 
drain fitting. 
Another object is the provision of such a drain fitting which overcomes the 
above-given disadvantages. 
SUMMARY OF THE INVENTION 
These objects are attained according to the instant invention in a drain 
fitting having a vessel formed with a laterally open housing outlet, at 
least one inlet, and an internal seat at the outlet. A pump is provided in 
the vessel and has a pump housing secured to the seat and having a pump 
output extending into the outlet and a pump intake, an impeller 
displaceable to move liquid through the housing from the intake to the 
output, and a motor in the housing driving the impeller. A check valve is 
provided in the pump output for preventing liquid flow back into the pump 
housing as well as means releasably securing the pump on the seat in the 
vessel. 
Thus the system according to the instant invention can be retrofitted 
relatively easily into an existing typical drain of the type provided at 
the upstream end of the sewer service line. Means is provided according to 
this invention for operating the pump to force liquid through the check 
valve into the service line when the liquid level in the vessel exceeds a 
predetermined limit, so that the system only operates when the effective 
liquid level in the sewer main is above the liquid level in the vessel. 
According to further features of this invention the fitting is provided 
with seal means between the pump output and the housing outlet for 
preventing flow from the vessel into the housing outlet except through the 
pump output. This seal means includes seals fitted between the pump 
housing and the vessel. The pump output according to the invention is 
above the pump intake and the pump housing is substantially closed except 
at the output and intake, so that the pump housing acts as a gas trap. 
According to this invention the pump housing is formed with a pump passage 
and a bypass passage. The pump passage passes over the impeller and the 
bypass passage past the impeller. In addition the pump is provided with a 
valve member displaceable between one position blocking the pump passage 
and permitting flow through the bypass passage and another position 
blocking the pump passage and permitting flow through the bypass passage. 
This valve member is a flap pivotal on the pump housing adjacent the 
intake. The pump passage includes a pumping chamber containing the 
impeller and closed on one side by the flap in the one position. The flap 
is so oriented that when the pump impeller is driven by its motor it 
pressurizes the pump chamber to force the flap into a position blocking 
the bypass passage, but when the pump impeller is not driven the flap 
blocks the pump passage for flow through the pump via the bypass passage. 
As a result the pump impeller will not be exposed to a constant flow of 
dirty liquid when it is not actually pumping, and flow through the fitting 
according to this invention is not impeded by the impeller when same is 
not being driven. 
The uppermost portion of the intake is spaced below the lowermost portion 
of the output by a distance equal generally to the height of the output. 
Thus good flow will be obtained through the arrangement according to this 
invention, with good gas-blocking ability. Similarly the flow 
cross-sections of the two passages are each as large as that of the 
output, so that the system according to the instant invention will not 
impede flow into the service line. 
The motor according to the present invention is electric and is provided 
with a feed wire, the vessel being formed with a throughgoing opening 
through which the wire passes and provided with a seal snugly surrounding 
the wire. A special conduit screwed via appropriate fittings to the vessel 
contains this wire. 
It is also possible according to the invention to provide a connecting pipe 
between the pump housing and the outlet. Furthermore it lies within the 
scope of this invention to provide the motor outside the vessel. 
According to this invention the pump can have a removable output tube 
forming the pump output and provided with the check valve. This output 
tube includes a pair of fitted-together and coaxial tube parts each 
provided with a respective such check valve. Releasable connecting means 
between the tube parts and the pump housing secures the tube parts 
together and secures the tube parts to the pump housing. The pump housing 
is provided at the outlet with a collar snugly fitting in the outlet and 
fitted in turn into the tube. The seal means includes a seal ring 
surrounding the collar and annularly engaging the vessel around the 
outlet. The check valve has a pivotal valve flap, or it can have a valve 
element formed by a ball.

SPECIFIC DESCRIPTION 
As seen in FIG. 1 the system according to this invention has a sewer main H 
provided well below ground level S and provided with manhole-access 
passages R, inputs N, and standard sewer service lines 5 which are 
normally tipped at about a 3.degree. slope to the horizontal toward the 
main H. Each such service line 5 is connected to the outlet 6 of a drain 
fitting 1 provided in the basement K of a building B. The drain fitting 1 
has according to this invention a vessel 3 in which a pump 4 acts as a gas 
trap and into which a waste line 2 empties. 
In the prior-art systems, as shown in dashed lines, the service line 5 is 
interrupted and connected to the intake of a pump P connected via a line L 
to a sump or storage vessel Z provided much higher than the sewer main H 
and connected through a steeply pitched service line F to the main H. This 
pump P operates nearly continuously to displace all liquid waste from the 
building B up to the vessel Z, whence it flows by gravity down to the main 
H. 
As seen in more detail in FIG. 2 the vessel 3 is of standard construction, 
corresponding to the usual shape, size, and dimensions for a floor drain 
that constitutes the last connection between the household drain lines 2 
and the service line 5. According to this invention the vessel 3 is formed 
with a seat 7 and is provided with studs or bolts 8 that allow a flange 23 
of the pump 4 to be fixed in place at the outlet 6. 
This pump 4 itself is a nonpositive displacement, axial-input/radial output 
pump having a rotor 30 whose shaft 31 carries an impeller 11 provided in a 
pump chamber 28 having a downwardly directed axial input 27 and a 
horizontally directed radial output 29. The pump 4 has a closed multipart 
housing 12 with a carrying bale 32 and a lower part 21, which latter is 
formed with horizontally opening intakes 13. Thus this housing forms a 
main downstream passage portion 14 opening at one end at the pump output 
15 and at the other end either through the pump-chamber output 29 into the 
chamber 28 or through another passage portion 37 into the region of the 
intakes 13. Between the lower edge u of pump output 15 and the upper edges 
of the intake openings 13 is a vertical distance G which therefore 
constitutes a gas trap when the vessel is filled at least to a level III 
with liquid waste, as the pump housing 12 is closed except at the intakes 
13 and output 15. 
A valve 37 is constituted by a valve flap 35 pivoted at 34 on the pump 
housing 12 and movable between a position shown in solid lines blocking 
the passage portion 36 and a position shown in dashed lines blocking the 
pump-chamber output 29. When the pump 4 is not energized flow through the 
portion 36 normally pushes this flap 35 into the dashed-line position so 
that flow through the pump 4 bypasses the pump chamber 28, as the 
resistance to flow through the pump chamber 28 is greater than passing it 
through the bypass passage 36. When the pump 4 is energized to rotate the 
impeller 11, however, the flap 35 moves down to block the bypass passage 
36 and allow flow through the pump 4 to take place exclusively via the 
pumping chamber 28. 
The pump 4 is provided at the pump output 15 with an output tube 16 formed 
by a pair of output-tube parts 55 and 55' which have slightly 
frustoconical ends so that they can fit snugly into each other, with the 
inner tube part 55 fitting over a collar 58 of the pump housing 12 and 
having a flange 59 clamped between an inner wall 60 of the vessel 3 and 
the pump housing 12. The end of the tube part 55 forms a pivot 17 for a 
lever 18 carrying a flap 38 which is engageable on a seat 39 of the tube 
part 55 to form an inner flap-type check valve 10. The outer tube part 55' 
engages with integral fingers 57 in recesses 56 in the inner tube part 55 
to hold itself in place thereon, these fingers 57 deforming elastically as 
the two parts 55 and 55' are fitted together. Another check valve 10' of 
construction identical to that of the check valve 10 of the inner tube 
part 55 is provided on the outer part 55'. Either of these valves 10 or 
10' could be provided with manual actuation means, so that the fitting 
could be manually closed if desired. 
The pump housing 12 is formed with a flange 23 at the output 15 and having 
a lower edge 24 received in the pocket 7. The bolts or studs 8 engage 
through the upper portion of this flange 23 to hold the pump 4 rigidly but 
removably in place in the vessel 3. A seal ring 54 is received in a groove 
63 of the flange 23 and is compressed between this flange 23 and the inner 
vessel surface 60. In order to ensure a good fit and seal at the pump 
output 15, the inner tube part 55 has a radially outer surface 61 that is 
frustoconically tapered and that presses radially outwardly against the 
inner periphery of the seal ring 54. 
The vessel 3 is provided internally adjacent the pump 4 with a particle 
trap 19 constituted as an upwardly open small vessel positioned directly 
under the holes 20 of a removable cover of the drain fitting 1 and also 
under the location where the conduit or conduits 2 empty into the vessel 
3. A float 70 is carried on an arm 71 above the particle-trap vessel 19 
and is connected to a controller 72 that switches the pump 4 on and off. 
To this end the pump 4 has a feed wire 64 that passes out of a side wall 
3a of the vessel 3 through a fitting formed of a pair of screwed together 
parts 65 and 67 compressing labyrinth-style seals 66. 
When the liquid level inside the vessel 3 rises to the level indicated at 
I, which is well above the lowermost part u of the outlet 15, the 
controller 72 switches on the pump 4 to force the liquid into the outlet 
16 and thence into the service line 5 past the check valves 10 and 10'. 
Unless there is back pressure holding the check valves 10 and 10' closed, 
the vessel 3 normally is not full above the level indicated at III, which 
level III is only slightly above the lowermost portion u of the outlet 15. 
FIG. 3 shows an arrangement similar in function to the arrangement of FIG. 
2, but wherein an outlet tube 16'" has a seat 39' for an inner check valve 
10a' whose valve member is a ball 40 rollable on an incline 41 upward away 
from the seat 39. The outer check valve 10 is identical to the inner check 
valve 10 of FIG. 2, having a valve flap 38' carried on an arm 18' pivoted 
at 17' and engageable with an annular seat 42. 
FIG. 4 shown as arrangement similar to that of FIG. 3 but wherein an outlet 
tube 16 has an inner check valve 10 identical to that of FIG. 2, and 
wherein an outer check valve 10a" is provided with a valve seat 43 for a 
ball 40' ridable along an incline 44 and captured in the tube 16' by a 
grate 45. 
In FIG. 5 the housing 12 has a collar 16" extending from its flange 23' and 
provided with a one-piece outlet tube 47 forming two seats 39" and 39'" 
for flap-type check valves identical to those of FIGS. 2 and 3, 
respectively. 
In FIG. 6 and arrangement is shown where the pump 4 is suspended on holders 
48 inside the vessel 3' and is connected to the outlet 6 by a short 
conduit 49. In addition the motor 30' here is mounted outside the vessel 
3'. 
The arrangement of FIG. 7 has a particle trap 50 mounted on the holders 48 
and the pump 4 is provided at its outlet with an additional small-diameter 
conduit 51 that bypasses the check-valve flap 38 and itself provided with 
a small check valve 52. Thus the pump 4 can work against the little check 
valve 52, which will take substantially less head to open so that the pump 
4 can be a relatively light-duty pump. In such an arrangement the vessel 
3' can be dimensioned rather large so that the light-duty pump 4 need not 
be able to handle peak loads. 
The system according to the instant invention therefore can take the place 
of a standard drain fitting, and can even be retrofitted into a standard 
drain fitting. It only functions when there is a backup in the service 
line, which rarely occurs more often than a few times a year, so that when 
there is no dangerous condition it consumes no energy. What is more, it 
can be easily serviced by removal of the entire pump and gas-trap 
assembly, and removal of this assembly gives good access to the service 
line 6 in the event it has to be snaked out.