Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
11~203C)
The present invention relates to a non-return valve,
more specifically the invention relates to a multiple inlet non-
return valve for abrasive fluids.
When an abrasive fluid such as mine tailings in a water
suspension is pumped through a pipe line, it is preferable to
have an abrasive lining within the pipe otherwise the interior
surface of the pipe is subject to excessive wear. Two or more
pumps in parallel, one of which is on standby, are usually used
for pumping abrasive slurries along pipelines. If one pump
should break down or have to be replaced, then the system still
work satisfactorily with one or more of the remaining pumps.
Such a system allows regular shut downs of one pump without
shutting down the system. To avoid back flushing to the shut
down pump, a non-return valve sometimes referred to as a check
valve is fitted in the line from the pump Preferably the non-
return valve is a multiple check valve which has two or more
inlets connected to two or more pumps, and one outlet leading to
the pipe line.
Multipl~ check valves are known, however, the majority
of these valves rely on flap members or closure members seating
over inlet ports and each flap member has a hinge at one side
which pivots about a hinge pin. Such a valve is satisfactory for
` liquids, however, i* is not satisfactory for-slurries, particu-
larly abrasive slurries, the particles in the slurry settle
around the hinge causing it to jam and very shortly the check
valve becomes inoperable. Attempts to provide a check valve which
does not have hinges therein have resulted in one type of valve
referred to as a ball check valve presently available and shown
in Canadian Patent 849,30~ to Harper. This valve has no pivoting
flap members for slurry particles to jam up. It includes a hard
rubber ball moving through a path of travel from one inlet to an
adjacent inlet seat. It has been found that the ball may become
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worn on one or more sides and can become stuck in the path of
travel causing the valve to become inoperative.
It is a purpose o~ the present invention to provide a
multiple inlet check valve for abrasive fluids that overcomes the
problems encountered with other types of check valves used in
this service.
The present invention provides a multiple inlet check
valve for abrasive fluids comprising a valve housing having at
least two inlet ports each of which is located on a separate
surface sloped toward one another and one outlet port, the
housing having an abrasive resistant lining throughout, a
closure member for each inlet port, the closure member including
a top abrasive resistant layer and a bottom abrasive resistant
layer with a rigid disc sandwiched therebetween, the bottom
abrasive resistant layer adapted to seal on the inlet port, and
a flexible flap integral with the closure member joined to each
inlet port.
In one embodiment each of the flexible flaps is joined
to an outer edge of each inlet port remote from the other inlet
ports. In another embodiment each of the flexible flaps is
joined to an inner edge of each of the two inlet ports, and
including a strap means between the closure members adapted to
keep one inlet port open when the other inlet port is closed,
and the other inlet port open when the one inlet port is closed.
In a preferred embodiment the check valve has two
inlet ports and the housing is in the shape of an inverted Y.
In another embodiment the abrasive resistant lining and the top
and bottom abrasive resistant layers of the closure member are
formed from rubber.
In drawings which illustrate the embodiments of the
invention,
Fig. 1 is an iso~etric view partially in section of
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one embodiment of a multiple inlet check valve of the present
invention.
~ig. 2 is a cross sectional elevation of the multiple
inlet check valve shown in Fig. l.
Fig. 3 is a cross sectional elevation of another
embodiment of a multiple inlet check valve of the present
invention with a strap between the closure members.
Referring now to the drawings a multiple inlet check
valve 10 is shown having a valve housing ll with an outlet port
12 at the top thereof, and two inlet ports 13 entering the lower
portion of the housing ll. The housing 11 as shown in the draw-
ings is welded steel plate construction and has an abrasive re-
sistant lining 14 throughout. In the embodiment shown the lining
is a rubber lining having a hardness of 35 to 40 Shore A Duro-
meter sold under the trade mark Linatex. The outlet port 12 is
circular and has a standard pipe flange 15. Both the outlet
port 12 and the flange surface have an abrasive resistant lining
thereon. A standard pipe flange may be connected to the flange
15 so the valve can be installed within a standard pipe line.
The valve housing 11 has two lower sloped surfaces 16.
These sloped surfaces 16 extend across each inlet port 13. Each
inlet port 13 is enclosed in an inlet port housing 17 which in
turn is connected to the valve housing ll beneath the sloped
surface 16. Between the valve housing ll and the inlet port
housing 17 is a check valve assembly 18 comprising a closure
member l9 formed of flexibe abrasion resistant material, prefer-
ably rubber, integral with a flexible flap 20 which is held be-
tween the main valve housing ll and the inlet port housing 17.
As shown in Figs. l and 2 the flexible flap 20 is at the upper
edge of the sloped surface 16 so that the closure members 19
open away from each other. A seat 21 is provided on the sloped
surface 16 so that when the valve is closed, the closure member
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19 fits against the seat 21 thus sealing the inlet port 13.
The closure member 19 has a rigid disc 22 backing onto the flex-
ible layer so that the closure member remains rigid when the
valve is closed. A top layer 23 of resilient material such as
rubber, surrounds the rigid disc 22 so that the complete inside
of the housing 11 is coated with an abrasion resistant material,
preferably rubber, and wear is kept to a minimum. The closure
member 19 remains against ths seat 21 when there is no pressure
on the underside of the inlet side of the valve, however, as
soon as the pressure in the inlet port 13 e~ceeds the pressure
in the housing 11, the closure member 19 opens and the flexible
flap 20 guides the closure member 19 so that it moves in a sub-
stantially 90 path.
As soon as the pressure in the inlet port 13 drops so
that it is equal to or less than the pressure in the housing 11,
the flexible flap 20 guides the flexible member 19 down to seal
the inlet port 13 against the seat 21. In the embodiment shown
in the drawings, the valve is in the shape of an inverted Y
having two inlet ports 13 at the bottom and one outlet port 12
at the top.
The two inlet ports 13 have standard flanges 24 which
may be connected to standard pipe lines and lead to the discharge
from the pumps. When one pump is operating, the closure member
19 opens and the slurry from the pump passes through the inlet
port 13 into the housing 11 and out through ths outlet port 12.
c~ t'~ r
Immediate]yithat pump is turned off the closure member 19 drops
onto the seat 21. There is hardly any slurry that flushes back
through the inlet port 13 when a pump is turned off~ If another
pump is turned on or is running when one of the pumps is turned
off, then flow continues out of the outlet port 12 without inter-
ruption. Both inlet ports may have flows pumping through at the
same time, and both closure members 19 then remain open. There
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are no exposed surfaces for wear by abrasive slurries, further-
more there are no hinges or other mechanical moving parts which
; can be affected by depositing solids out of the slurry thereon.
In the embodiment shown in Fig. 3, the flexible flap
20 is at the lower edge of the sloped surface 16 so that the
closure members lg open towards each other. A strap 30 extends
from one closure member 19 to the other joined to the top of
each closure member 19 by a machine bolt 31. The strap 30 is of
sufficient length so that when one or the other of the closure
members 19 are open, the other port 13 is closed. Both ports
13 may be open but only one port may be closed. This configura-
tion is used to prevent slurry settling in the housing 11. In
some situations where there are a large number of solid particles
conveyed through a pipe line, a stoppage of both pumps must not
allow both ports to close because the solid particles settle
down in the valve housing causing silting which may prevent the
closure members 19 from opening. Thus, the present embodiment
provides a valve wherein one port 13 is always open and silting
cannot occur in the housing.
Whereas two inlets are shown in the drawings it will
be apparent to those skilled in the art that a plurality of in-
lets of any feasible number could be used to pump slurries into
a housing. One or more outlets may then be provided for feeding
the slurry to a conveying pipe line. As shown in the drawing,
the closure member 19 rests on a seat 21 which is sloped at an
angle to the horizontal. This is a preferred embodiment?
however, the seat may be horizontal or may be positioned at
almost any location provided one of the closure members 19 can
close when there is no flow from that inlet port 13 into the
interior of the housing 11. The configuration of the housing
11 shown in the drawings is formed of welded steel plate, however,
this configuration could be a casting. The shape of the housing
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could be completely different provided the flaps had
sufficient space to open to leave access from the inlet port
to the outlet port, this is all that is required.
