Note: Descriptions are shown in the official language in which they were submitted.
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WO 96/00853 PCT/EP95/02411
Pump-Protecting Valve
The invention relates to a pump-protectinc valve with a
valve housing, with a pump connector disposed in a main flow-
through direction, with a feed water connector located opposite
the pump connector, with a bypass connector disposed laterally in
respect to the main flow-through direction and a mounting plate
closure located opposite the bypass connector, between which a
check valve disk, which is spring-loaded if required, is-seated
coaxially in respect to the bypass connector and mounting plate
closure in an axially displaceable manner and actuates an at least
single stage throttle valve which is coaxial with it, so that the
throttle valve is fully open when the check valve disk is closed,
and produces a bypass to the bypass connector from the side of the
pump connection, wherein a valve seat of the valve housing for the
check valve disk is located opposite the mounting plate closure.
A pump-protecting valve is known from DE ~-2 30 697 A1, on
which a spindle seated in the main flow-through direction and
having a check valve disk for controlling the bypass flow by means
of a perforated basket throttle valve is disposed. The
disadvantage in connection with this known pump-protecting valve
lies in that the various components of the valve are only
accessible after the valve housing has been removed from the
conduit of pipes.
Furthermore, another valve is known from DE-OS-1 906 305,
wherein the throttle valve is constituted by a second valve disk
located coaxially with the valve disk of the main straight-way
valve, wherein the two valve disks are fastened on a common,
vertically oriented valve rod, whose length between the valve
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disks is greater than the distance between the flow-through
opening and the overflow opening, so that with the outlet line
closed, the weight of the movable valve elements and the pressure
difference acting on the valve disk of the overflow opening opens
the overflow opening and closes the flow-through opening, while
with the opened outlet opening and a defined pressure difference
between the inlet and the outlet chamber, the pressure difference
acting on the valve disk of the flow-through opening opens the
flow-through opening and closes the overflow opening. With this
construction the valve seat of the throttle valve is necessarily
located on the side facing away from the mounting plate closure.
To service the valve it is necessary here to disassemble at least
the bypass connection in order to remove the throttle valve disk
through the bypass connector. After that the main valve disk can
be removed from the side of the mounting plate. Maintenance is
also made more difficult here because of the required dismantling
of the bypass line.
It is the object of the instant invention to create a pump-
protecting valve which is easy to manufacture and makes rapid
maintenance work possible without it being required to first
dismantle conduits of pipes connected with the valve.
This object is attained in that the check valve disk and
the throttle valve are seated so they can be removed from the
valve housing through the mounting plate closure.
The advantages which can be attained consist in particular
in that simple access to~all closure elements of the valve by
means of the removal of the mounting plate closure is made
possible. This leads to a simple way of exchanging the valve
elements.
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Contrary to a technical prejudice, the flow characteristics
in the main flow direction are not essentially worsened because of
-the diversion in the area of the valve. No greater friction
losses are created than with conventional valves whose check
valves are disposed in the main flow direction.
The dependent claims contain different advantageous
embodiments and further developments of the valve in accordance
with the invention.
Preferred exemplary embodiments of the invention will be
described in more detail below by means of the drawings. Shown
are in:
Fig. 1, a cross section through a pump-protecting valve in
accordance with a first exemplary embodiment;
Fig. 2, a cross section through a pump-protecting valve in
accordance with a second exemplary embodiment;
Fig. 3, a cross section through a pump-protecting-valve in
accordance with the first exemplary embodiment in Fig. 1 with an
additional check valve in the bypass line and an additional
connector for a manual starting line;
Fig. 4, a cross section through a pump-protecting valve in
accordance with a third exemplary embodiment;
Fig. 5, a cross section through a throttle valve spindle
from a pump-protecting valve in accordance with the third
exemplary embodiment in Fig. 4;
Fig. 6, a cross section through a pump-protecting valve in
accordance with the third exemplary embodiment in Fig. 4 with an
additional check valve in the bypass line and an additional
connector for a manual starting line;
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WO 96/00853 PCT/EP95/02411
Fig. 7, a cross section through a throttle valve spindle
from a pump-protecting valve in accordance with the third
exemplary embodiment with the additional check valve in Fig.6;
Fig. 8, a cross section through a pump-protecting valve in
accordance with the third exemplary embodiment in Fig. 4, but here
with a pump housing formed out of a solid material.
The pump-protecting valve (1) consists of a valve housing
(2, 2D) having flow-through connectors (4, 5, 12, 80) for a fluid
medium. The fluid medium is guided in a main flow-through
direction (3) through a pump connector (4) of the valve housing
(2, 2D) into a following feed-water connector (5) disposed on
the opposite side of the housing (2, 2D).
The valve housing (2, 2D) has a center wall (23) extending
essentially parallel with the main flow-through direction (3),
which divides the interior of the housing (2, 2D) into a chamber
on the side of the feed water connector-and one on the side of the
pump connector. A flow-through opening for the main flow disposed
crosswise to the main flow-through direction is located in this
center wall. This flow-through opening has a valve seat ring (22)
on the side of the feed water connector and is closed by means of
a check valve disk (10), pressed by the force of a spring against
the opening.
The walls of the pump connector (4) on the one hand, and of
the feed water connector (5) on the other, are shaped in such a
way that the flowing medium undergoes the smallest possible
friction losses during a change of direction of at least 90
degrees. For this purpose a cylinder-shaped wall (6) of the pump
connector (4) extends at an acute angle in respect to the main
flow-through direction (3). In the further course of the pump
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connector (4), its wall makes a transition into a bowl-shaped wall
(7), which deflects the medium crosswise in respect to the main
flow-through direction (3) and guides it on into the area of the
feed water connector (5). In the connecting area with the pump
connector (4)j the feed water connector (5) has a bowl-shaped wall
(8), along which the fluid medium approaches the direction of the
perpendicular main flow-through direction (3).
Inclined walls (9) disposed on the downstream side assure
that the outlet opening of the feed watex connector (5) is
disposed coaxially in respect to the inlet opening of the pump
connector (4).
As soon as the flow-through quantity is disrupted
downstream of the feed water connector (5), the check valve disk
(10) disposed crosswise in respect to the main flow-through
direction (3) closes. In cooperation with a throttle valve (11,
llA, llB) disposed coaxially with the disk, the fluid medium is
deflected into a bypass connector (12, 12D) extending crosswise
with the main flow-through direction (3) and coaxially with the
valve disk (10).
The housing (2, 2D) is closed opposite the bypass connector
(12, 12D), which is arranged coaxially with the valve disk (10),
by means of a mounting plate closure (20), which is connected with
the valve housing (2, 2D) by screw connections (26) which are
screwed into blind bores (30) in the housing (2, 2D).
Essentially three exemplary embodiments are represented in
the drawing figures, two of which are designed mainly for
employment in systems of low pressure, and one as a high pressure
version.
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W0 96/00853 PCT/EP95/02411
In a first exemplary embodiment in accordance with Fig. 1
and Fig. 3, the throttle valve is designed as a perforated
basket throttle valve (11). This perforated basket throttle
valve (11) consists of a sleeve (18) disposed on the check valve
disk (10), which is placed over a regulating bushing (14)
provided in the valve housing (2, 2D), constituting the inflow
to the bypass connector (12).
This regulating bushing (14) is screwed into the bypass
connector (12) from the housing interior coaxially with the bypass
connector (12). An annular sealing face (60) is formed on the
surface of the regulating bushing (14) at the end of the thread
(63) of the regulating bushing (14) and in the screwed-in state
presses against a sealing seat (61) in the bypass connector (12)
and seals the regulating bushing (14) against the bypass connector
(12).
The front face of the regulating bushing (14) oriented
toward the bypass connector (12) has a flow-through opening. The
opposite front face of the regulating bushing (14) is embodied as
a closed front face (15).
The surface of the regulating bushing (14) has a plurality
of openings (16). In a position of the pump-protecting valve (1)
crosswise to the flow, these openings (16) correspond to through-
bores (17) in the sleeve (18) on the check valve disk (10). As
soon as the main flow is blocked on the downstream side, the
sleeve (18) of the check valve disk (10), pre-stressed by means of
a spring (19), is pushed completely on the regulating bushing (14)
of the perforated basket throttle valve (11). The edge (21) of
the check valve (10), held on the exterior by the mounting plate
closure (20), simultaneously pushes against a reinforced valve
seat ring (22) of the valve seat housing (2). In this position
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the check valve disk (10) completely closes the flow-through
opening formed in a center wall (23) of the valve housing (2) with
its piston. The flow-through in the direction of the feed water
connector (5) is completely blocked by this.
Instead, the fluid medium is guided through the through-
bores (17) of the sleeve ~18) and through the openings (16) of the
regulating bushing (14) inside the regulating bushing (14) and
through its one front face leaves the valve housing (2) in the
transverse direction.
The openings (16) extend radially in the surface area of
the regulating bushing (14). Several through-bores (17) of the
sleeve (18) are assigned per opening (16) and are pushed one after
the other over the respective opening (16). The flow to the
bypass connector (12) in the partial closing positions of the
check valve disk (10) is respectively controlled by means of a
suitable number, disposition and size of the corresponding
through-openings (16, 17) in such a way that a predetermined
steady (modulated) regulation of the minimum flow-through quantity
is assured. The minimum amount is the quantity of medium flowing
through required by the upstream connected (to be protected) pump
so that it does not become thermally overloaded.
When used as pump-protecting valve for centrifugal pumps,
only half the stroke of the valve is preferably used, i.e. the
bypass is closed as soon as the main flow-through valve is half
opened. If the valve (1) is to be used as an overflow valve for a
positive displacement pump, the entire stroke can also be used in
a simple manner by widening the perforated area in the regulating
bushing (14) and/or in the sleeve (18).
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WO 96/00853 PCT/EP95/02411
Because of the simple design of the valve elements, the
bores (16, 17) can be easily adapted to special operational
conditions by reworking in situ.
If the blockage of the flow on the downstream side of the
feed water connector (5) is removed, the check valve disk (10) is
brought into an opening position against the spring force wherein
the flow-through opening of the center wall (23) is open and the
fluid medium flows only in the main flow direction.
So that a defined pressure is exerted on the check valve
disk (10) from the direction of the pump connector or the throttle
valve, and a defined force balance is assured in the valve (1),
the sleeve (18) has relief bores (27), which connect the space
between the closed front wall (15) of the regulating bushing (14)
and the check valve disk (10) with the pump connector (10). -
The transversely oriented check valve disk (10) is held in- the housing (2, 2D), coaxially in respect to the bypass connector
(12, 12D) and axially displaceable, by means of the sleeve (18)
guided on the regulating bushing (14) of the perforated basket
throttle valve (11). The valve disk (10) has a guide sleeve (24)
on the side toward the mounting plate which is connected in a
loose fit with a sleeve (25) of the mounting plate closure (20).
The check valve disk (10) with the sleeve (18) of the
throttle valve (11) can be easily taken out together with the
mounting plate closure (20) by releasing the screw connection
(26).
In order to also take the regulating bushing (14) of the
throttle valve (ll) out easily after the valve disk (lO) has been
removed, the outer surface (62) of the regulating bushing (14) at
the end pointing to the mounting plate closure (20) is embodied as
8-
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W0 96/00853 PCT/EP95/02al
an external hexagon for receiving a corresponding commercially
available tool, for example a hollow socket wrench. The
- regulating bushing (14) can then be screwed out of the bypass
connector (12, 12D) through the mounting plate closure (20) by
means of this tool.
In place of an external hexagon, the regulating bushing
(14) can of course also be provided with-another tool receptacle,
such as a hexagon socket wrench, torque wrench receiver or a slit
for the insertion of a screw driver.
In accordance with a second exemplary embodiment in Fig. 2,
the throttle valve (llA) is designed as a single-stage cone valve.
The elements below, which correspond to the first exemplary
embodiment, are provided with the same reference numerals.
~The cone valve consists of a valve cone (28) which is
connected via a central shaft (29) and bars (30) extending
radially outward from the shaft (29) with the check valve disk
(10) and is disposed coaxially with it. The valve cone (28) is
seated axially displaceable in a regulating bushing (14A). The
regulating bushing (14A) has a section (31) against whose inside
(32) the valve cone (28) rests with all its surfaces when the
bypass valve is closed. The valve cone (28) is guided with
sliding fit in the regulating bushing (14A). If the check valve
disk (10) is moved into the closed position, the valve cone (28),
and subsequently the bars (30), slide on the inside (32) of the
section (31) until the check valve disk (10) pushes against the
valve seat ring (22).
A pressure relief bore (33), axially extending through the
cone valve, the check valve disk (10) and the guide sleeve (24),
is provided for pressure relief. It connects the inner chamber
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WO 96/00853 PCT/EP95/02411
(34) of the guide sleeve (24) with an interior chamber of the
regulating bushing (14A) located on the bypass side of the valve
cone (28). With its guide sleeve (24), the check valve disk (10)
is placed sealingly in the bushing (25) of the mounting plate
(20), so that the fluid medium guided through the pressure relief
valve (33) cannot flow off in the main flow direction to the feed
water connector (5).
Since in this exemplary embodiment the regulating bushing
(14A) is hardly subjected to any wear and can also not become
plugged, in principle the regulating bushing (14A) can also be
fixedly connected~with the housing in this case, for example by
shrinking.
In the exemplary embodiments of the pump-protecting valve
in accordance with the invention represented up to now, the
throttle valve (11, llA) does not close 100~, a defined small
leakage flow always remains, which flows off into the bypass
connector. Therefore these exemplary embodiments are only
suitable for employment in low pressure applications.
But when used in high-pressure applications, the bypass
must be absolutely sealed, leakage via the bypass is not
permissible, because otherwise the throttle valve would be
destroyed within a few hours by erosion and cavitation damage.
An appropriate high-pressure version is represented in Fig.
4. In this case the throttle valve (llB) is a three-stage valve
with a regulating spindle (50) disposed on the valve disk (10) and
having valve cones (51A, 51B) placed behind each other coaxially
in respect to the valve disk (10) and with a valve disk (54). The
regulating spindle (50) is guided in an axially displaceable
manner in a regulating bushing (14B). In the opened position of
-10 -
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the check valve disk (10), the valve cone (51A) which is first on
the mounting plate side pushes with its appropriately shaped rear
edge (53) against a sealing seat (52) disposed at the front inside
the regulating bushing (14B) and pointing in the direction toward
the bypass connector. The valve cones (51A, 51B) and the valve
disk (54) located at the rear rest with their cylindrical sliding
faces (42) against cylindrical wall areas (43) of the regulating
bushing (14B) .
When the check valve disk (10) is moved into the closed
position, the sliding faces (42) of the valve cones (51A, 51B) or
the valve seat (54) move along the cylindrical wall areas (43) OL
the regulating bushing in the direction toward the bypass
connector until the valve cones (51A, 51B) reach the widenings
(44) of the control bushing (14B), so that the fluid medium can
flow off on the bypass side. Then the regulating spindle (50) is
only guided over the valve disk (54) by bars (58) resting on the
inner wall of the regulating bushing (14B) in the rear area on the
bypass connector side. The wall areas between the bars (58) are
recessed, tapering conically toward the back in order to assure
here, too, a continuous widening of the flow-through opening when
the regulating spindle is displaced.
The regulating spindle (50) is interlockingly and
frictionally connected with the check valve disk (10). For this
purpose the check valve disk with its guide sleeve (24) is
centrally drilled out. The portion of the regulating spindle(50) on
the side of the mounting flange is pushed into this bore from the
side of the-bypass connector and contacts the valve disk (10) with
a reinforcing ring (56) of the regulating spindle (50) engaging
the check valve disk (10). This reinforcing ring (56) is enclosed
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WO 96/00853 PCT/EP95/02411
in a seal (46) for the sealing connection with the check valve
disk 10. The regulating spindle (50) is clamped on the check
valve disk (10) via a spring washer (57) which reaches around the
end of the regulating spindle (50) on the side of the mounting
plate and pushes against the guide sleeve (24) of the check valve
disk (10).
The check valve disk (10) is guided by means of its guide
sleeve (24) in the bushing (25) of the mounting plate (20) in the
same way as in the prior exemplary embodiments.
A pressure relief bore (55), which extends axially from the
valve disk (54) disposed on the bypass side through the regulating
spindle (50) into the area of the inner chamber (34) of the guide
sleeve (24) is provided for pressure relief. A seal (58) is
provided for sealing between the bushing (25) and the guide sleeve
(24).
The base of the valve disk (54) on the bypass side and
the base, toward the interior chamber (34), of the guide sleeve
(24) with the inserted regulating spindle (50) should preferably
be of the same size in order to neutralize the pressure, usually
unknown, in the bypass connector (12, 12D).
A thread for receiving a threaded rod is threaded into the
regulating spindle (50) at the end of the pressure relief bore
(55) toward the mounting plate for easier removal of the
regulating spindle (50) during disassembly.
The embodiment of the throttle valve (llB) in three stages
takes care of higher pressure conditions, especially in the open
state of the throttle valve (llB). In an alternative manner it is
also possible to embody the throttle valve (llB) with one, two and
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WO 96/00853 PCT/EP95/02~11
of course also more than three stages if the amount of pressure is
correspondingly lower or higher.
Optionally, each of the exemplary embodiments mentioned can
be provided with an additional bypass check valve (70) in the
bypass connector (12, 12D). This is shown in connection with the
first exemplary embodiment in Fig. 3; in Fig. 4 for the third
exemplary embodiment. This check valve (70) is intended to
prevent the bypass tl2) from being drained in the direction toward
the pump housing when the installation is shut down.
The check valve (70) essentially consists of a sealing
hollow piston (74), guided in a sleeve (76) and open toward the
bypass side, which is pressed by a spring (75) with the outer edge
of its front face on the side of the mounting plate against a
sealing face (72) disposed in the sleeve (76). On the bypass side
the spring (75) presses against a support ring (71), which is held
by means of a spring washer (79) in the sleeve (76). If
sufficient pressure is generated in the sleeve (76) ahead of the
check valve (70), the sealing piston (74) of the check valve (70)
is pushed back by this into a widening in the inner wall of the
sleeve (76) and the medium can flow off past the front face
through drain holes (73) disposed in the lateral wall of the
sealing piston (74), through the sealing piston (74) and the
support ring (71) of the check valve (70) to the bypass connector
(12, 12D).
In the low pressure version with the perforated basket
throttle valve (11), the regulating bushing (14) is used at the
same time as a guide sleeve (76) for the check valve and has an
appropriate sealing face (72). The sealing piston (74) is
inserted from the side of the bypass and is then clamped via a
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spring (75) and the bottom part (71) with a spring washer (79) in
the regulating bushing (14).
In the high pressure version the check valve is in a
separate guide sleeve ( 76) and is inserted behind the screwed-in
regulating bushing (14B) into the bypass connector and is sealed
against it by a seal ring (77). In order to be able to remove the
check valve (70) also through the mounting plate closure (20), the
sealing piston (72) of the check valve (70) has a threaded bore
(78) on the front, into which a threaded rod can be screwed.
In the high pressure version the entire disassembly of the
valve elements is performed as follows:
First the mounting plate closure (20) is removed. Then the
safety ring (57) is removed from the regulating spindle (50).
Subsequently the valve disk (10) is pulled off the regulating
spindle (50), then the regulating bushing (14B), together the
regulating spindle (50), is screwed out of the bypass connector
(12) with the help of a commercially available hoilow socket
wrench and is removed through the mounting plate closure-(20).
After this the regulating spindle can be pulled out through
the back of the regulating bushing (14B). If desired, a threaded
rod or the like, which can be screwed into the face of the
regulating spindle (50) on the side of the mounting plate, can be
used to aid the removal of the regulating spindle (50) with the
regulating bushing (14B) and for pulling the regulating spindle
(50) out of the regulating bushing (14B). To remove the check
valve (70), a threaded rod is then screwed into the threaded bore
(78) at the head of the sealing piston (72), and the entire check
valve (70) is pulled out of the bypass connector (12). Finally,
-14-
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WO 96/00853 PCT/EP95/02~11
the check valve (70) can be disassembled following the removal o
the spring washer (79) from the sleeve (76).
A further possible option is the installation of a so-
called manual starting line via a manual starting connector (80).
This manual starting connector is integrated directly into
the mounting plate closure (20) and connected with the interior of
the valve housing (2) via through-holes (81) in the mounting plate
or in a flanged section (82) of the guide sleeve (25) for the
check valve disk (10).
For throttling the flow, there is at least one, and in
the high pressure version several, for example three, perforated
disks (83), the so-called throttle disks, which are disposed one
behind the other in the manual starting connector (80).
Such a manual starting line is used in certain --
installations for starting in order to protect the bypass side
during start-up. For this purpose a valve located in the manual
starting line is opened (these valves are not shown in the
representation), while a valve, following the feed water connector
(5), is closed in the main flow-through direction (3). When the
pump is started up, the medium then flows first through the main
valve past the valve disk (10) and through the manual starting
line back into the supply reservoir. The bypass remains closed
during the start-up. Only after some time is the manual starting
valve closed and the main flow-through valve opened, so that the
bypass valve is then also operating.
The valve housing (2, 2D) is preferably made as a cast housing
(2). This reduces manufacturing costs, reduces the material used
and is therefore gentler on the resources. When using special
materials which cannot be cast, for example for using pump-
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WO 96/00853 PCT/EP95/02411
protecting valves (1) in areas in which resistance against saltwater or chemicals, or a special temperature resistance is
required, the housing (2D) can also be formed from a solid
material, for example special VA materials, copper or others.
A corresponding exemplary embodiment is shown in Fig. 8.
The arrangement inside the formed housing (2D) and a cast housing
(2) is essentially the same, except for a few changes on account
of production techniques.
In the cast housing version the bypass connector (12) is
either screwed into a transverse connector (13) of the valve
housing (2) and provided with a sealing weld seam (64) (for
example Fig. 1), or is only welded to the transverse bars (13)
(Fig. 2).
In the formed embodiment the entire bypass connector (12D)
is flanged to the valve housing (2D) by means of a screw
connection (65) and sealed by means of a seal ring (Fig. 8).
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