U.S. patent number 3,891,352 [Application Number 05/409,809] was granted by the patent office on 1975-06-24 for liquid-piston type slurry pumping system.
This patent grant is currently assigned to Mitsubishi Kinzoku Kabushiki Kaisha. Invention is credited to Junya Tsukamoto.
United States Patent |
3,891,352 |
Tsukamoto |
June 24, 1975 |
Liquid-piston type slurry pumping system
Abstract
A liquid-piston type slurry pumping system is composed of a
rotary pump unit for delivering a pressurized operating fluid
having a specific gravity different from that of the slurry, at
least two valve boxes each having a suction valve and a delivery
valve connected to a slurry pipe line, at least two liquid
containers connected respectively to the valve boxes, passage means
extending between the containers and the pump unit, means for
changing over the passage means thereby to cause the operating
fluid to flow alternately into the liquid containers, detecting
means provided in each of the liquid containers for detecting
excessive displacement of a boundary surface formed between the
operating fluid and the slurry, and a controller for controlling
the operation of the fluid-passage changeover means in response to
a signal from the detecting means, whereby the movement of the
boundary surfaces in the containers is controlled by the controller
for stabilizing the operation of the pumping system.
Inventors: |
Tsukamoto; Junya (Hyogo,
JA) |
Assignee: |
Mitsubishi Kinzoku Kabushiki
Kaisha (Tokyo, JA)
|
Family
ID: |
14947581 |
Appl.
No.: |
05/409,809 |
Filed: |
October 26, 1973 |
Foreign Application Priority Data
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Nov 2, 1972 [JA] |
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47-126937 |
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Current U.S.
Class: |
417/101;
417/900 |
Current CPC
Class: |
F01L
25/08 (20130101); F04F 1/02 (20130101); F04B
9/113 (20130101); F04B 9/1172 (20130101); F04B
53/141 (20130101); Y10S 417/90 (20130101) |
Current International
Class: |
F01L
25/08 (20060101); F01L 25/00 (20060101); F04B
53/14 (20060101); F04B 53/00 (20060101); F04B
9/00 (20060101); F04B 9/113 (20060101); F04B
9/117 (20060101); F04F 1/02 (20060101); F04F
1/00 (20060101); F04f 011/00 (); F04b 015/02 () |
Field of
Search: |
;417/101,102,103,125,900,398,401 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,556,179 |
|
Oct 1969 |
|
DT |
|
245,512 |
|
Nov 1969 |
|
SU |
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2,002,190 |
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Aug 1970 |
|
DT |
|
Primary Examiner: Freeh; William L.
Assistant Examiner: Gluck; Richard E.
Attorney, Agent or Firm: Wenderoth, Lind & Ponack
Claims
What we claim is:
1. A liquid-piston type slurry pumping system operable in a slurry
pipe line, said system comprising: a pump unit of a type
continuously delivering a pressurized operating fluid which is of a
specific gravity different from that of slurry to be pumped and is
substantially immiscible with, insoluble in, and unreactive with
the slurry; at least two valve boxes each including a suction valve
and a discharge valve connected respectively to the pipe line; at
least a pair of liquid containers connected respectively to the
valve boxes; passage means connecting said containers and said pump
unit; means for changing over said passages between the pump unit
and the liquid containers, thereby to introduce the operating fluid
into the liquid containers alternately; detecting means provided in
each of the containers for detecting any displacement in excess of
a predetermined value of a boundary surface formed between the
fluid and the slurry coexisting in the containers; a controller for
controlling the operation of the fluid-passage changeover means in
response to signals from said detecting means, whereby the
pulsations of the boundary surfaces in the containers are
controlled in response to the detected results of the detecting
means, and the operation of the pumping system is thereby
stabilized; and
a piston-cylinder device provided between the liquid containers and
said fluid-passage changeover means, said device being comprised of
means isolating the operating fluid from the slurry but
transmitting hydraulic displacement between the operating fluid and
the slurry, first and third cylinders respectively including
pistons connected together operatively, and second and fourth
cylinders respectively including pistons connected together
operatively, the first side of the piston in the first cylinder and
the second side of the piston in the second cylinder being
connected to a passage in said fluid passages changing over means,
the second side of the piston in the first cylinder and the first
side of the piston in the second cylinder being connected to
another passage in said fluid passages changing over means, the
first side of the piston in the third cylinder and the second side
of the piston in the fourth cylinder being connected to one liquid
container, the second side of the piston in the third cylinder and
the first side of the piston in the fourth cylinder being connected
to the other liquid container, said operating fluid occupying both
sides of each of the first and second cylinders, and the interiors
of the third and fourth cylinders being occupied by an additional
operating fluid which forms a boundary surface in each of the
liquid containers between itself and the slurry.
2. a liquid-piston type slurry pumping system as set forth in claim
1 wherein said operating fluid used in the pumping unit is a gas
such as air or steam.
3. In a liquid-piston type slurry pumping system for conducting a
slurry through a pipeline and including pumping means having a
suction side and a pressure side and continuously delivering a
pressurized operating fluid having a specific gravity lower than
that of the slurry and substantially immiscible with, insoluble in,
and unreactive with the slurry, at least one pair of valve boxes
connected, respectively, to the pipeline in parallel relationship
to each other and each including a suction valve and a discharge
valve, at least one pair of liquid containers respectively
connected to said valve boxes, a boundary surface formed in each of
said containers between operating fluid and slurry contained
therein, passage means connecting said containers and said pumping
means, means for changing over said passage means to alternatively
introduce the operating fluid delivered from said pumping means
into one of said containers, detector means for detecting a level
of said boundary surface in each of said containers, and control
means for controlling the operation of said changeover means in
response to detection of the level by said detecting means, the
improvements comprising:
said detector means for each container being comprised of means for
detecting a displacement of said boundary surface beyond a
predetermined raised level in the container, each container being
connected at an upper portion thereof to said passage means;
said changover means being comprised of a single sliding changeover
valve movable between a first position in which a first of said
containers is connected to the suction side of said pumping means
and a second container is connected to the pressure side and a
second position in which said first container is connected to the
pressure side of said pumping means and said second container is
connected to the suction side of said pumping means;
said control means being adapted to shift said changeover valve
from said first position to said second position when said boundary
surface in said first container reaches said predetermined raised
level, and from said second position to said first position when
said boundary surface in said second container reaches said
predetermined raised level;
a piston-cylinder device interposed between said liquid containers
and said changeover valve, said piston-cylinder device separating
said passage means into a first section containing a first
operating fluid adapted to be pumped by said pumping means and a
second section containing a second operating fluid, said boundary
surface in each container being formed between said second
operating fluid and the slurry, said piston-cylinder device
isolating the first operating fluid from the slurry but
transmitting hydraulic displacement between said first operating
fluid and the slurry, said piston-cylinder device being comprised
of first and third cylinders each including a piston, said
respective pistons operatively connected together, and second and
fourth cylinders each including a piston, said pistons being
operatively connected together, said pistons of each cylinder
dividing said cylinder into two regions, said first and second
cylinders being connected to a first common passage adapted to be
selectively connected to the pressure and suction sides of said
pumping means by said changeover valve, said first and second
cylinders being connected to a second common passage adapted to be
selectively connected to the suction and pressure sides of said
pumping means by said changeover valve, said first and second
common passages respectively communicating with different regions
in said first and second cylinders, said third and fourth cylinders
being connected to said first and second liquid containers in
different regions thereof, said first operating fluid occupying
both regions of said first and second cylinders, both regions of
said third and fourth cylinders being occupied by said second
operating fluid.
4. The improved liquid-piston type slurry pumping system as set
forth in claim 3, wherein said first operating fluid is a gas such
as air or steam.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to liquid-piston type pumping
systems to be used with liquids containing foreign materials and/or
abrasive particles, such as muddy water or ore slurry, and more
particularly to improvements in the pumping system.
A liquid-piston type pumping system which comprises a plunger pump
and a liquid container through which the plunger pump is connected
to a valve box having a suction valve and a discharge valve is
known. During operation, the interior of the valve box and the
lower part of the liquid container is filled with a liquid
containing foreign materials and/or abrasive particles, such as
muddy water or ore slurry (hereinafter simply called a slurry),
while the interior of the plunger pump and the upper part of the
liquid container is occupied by an operating fluid, such as oil,
having a lower specific gravity than that of the liquid (or slurry)
and being substantially immiscible with, insoluble in, and
unreactive with, the slurry.
In the liquid container, a distinct boundary surface is formed
between the slurry, occupying the lower part of the container, and
the operating fluid, which is immiscible with the slurry and
occupying the upper part of the container, and the boundary surface
is moved up and down in a reciprocating manner in accordance with
the operation of the plunger pump, the surface thus acting in the
manner of a liquid piston or a diaphragm piston. The up-and-down
movement of the boundary surface causes opening and closing of the
suction valve and the discharge valve in the valve box connected to
a slurry pipe line, and hence the slurry is pumped at a
comparatively high pressure through the pumping system.
Although the above described slurry pump system is advantageous in
that the plunger pump can be operated with an operating fluid
absolutely free from abrasive particles and intrusion of the slurry
into the plunger pump is effectively prevented by the provision of
the liquid container, the plunger pump constituting an essential
component of the conventional system requires a considerable size
and weight when it is desired to increase the capacity of the
pumping system, and the operation thereof is not sufficiently
smooth and noiseless. Furthermore, a volumetric relation must be
maintained between the sizes of the valve box, liquid container,
and the displacement of the plunger pump, and a mere increase in
the displacement of the plunger pump will produce a hazardous
exceeding of the predetermined limitations of the boundary surface
in the liquid container. In addition, the maintenance of the
boundary surface within an appropriate range in the liquid
container at the starting stage of the pumping system is essential,
and hence automatic operation or remote control of the pumping
system has been substantially difficult.
SUMMARY OF THE INVENTION
In view of the above noted difficulties in the conventional
liquid-piston type slurry pump system, a primary object of the
present invention is to provide an improvement whereby automatic
operation or a remote control of the pumping system can be executed
without accompanying severe vibration or abnormal pressure
rise.
Another object of the invention is to provide an improved
liquid-piston type slurry pump system wherein the size and weight
of the entire system can be substantially reduced, and the
transportation and mounting thereof can be substantially
facilitated.
Still another object of the invention is to provide an improved
liquid-piston type slurry pump system wherein a rotary type pump
unit can be used instead of a plunger type pump unit, whereby the
delivery of the pump system can be varied without any trouble.
A further object of the invention is to provide an improved
liquid-piston type slurry pump system, the essential parts of which
are available on the market, whereby the production cost of the
pumping system can be substantially reduced.
The above described and other objects of the present invention can
be achieved by an improved liquid-pistion type slurry pump system
comprising: a pump unit of a type continuously delivering a
pressurized operating fluid of a specific gravity different from
that of slurry to be pumped and being substantially immiscible
with, insoluble in, and unreactive with the slurry; at least two
valve boxes each having suction and discharge valves connected
respectively to a slurry pipe line; at least two liquid container
means respectively connected to the valve boxes; passage means
connecting the containers and sais pump unit; means for changing
over the passages extended between the pump unit and the liquid
container means thereby to introduce the operating fluid into the
liquid container means alternately; detecting means provided in
each of the container means for detecting any displacement in
excess of a predetermined value of a boundary surface formed
between the fluid and slurry coexisting in the container means
during operation of the pump system; and a controller for
controlling the operation of the fluid-passage changeover means in
response to a signal from said detecting means, whereby the
pulsations of the boundary surfaces in the container means are
controlled in response to the detected results of the detecting
means, and the operation of the pumping system is thereby
stabilized.
The invention will be more clearly understood from the following
detailed description of the invention when read in conjunction with
the accompanying drawings, wherein like parts are designated by
like reference numerals and characters.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a diagram schematically showing a liquid-piston type
slurry pump system constituting a first embodiment of the present
invention;
FIG. 2 is a diagram schematically showing another example of the
liquid-piston type slurry pump system constituting a second
embodiment of the present invention; and
FIG. 3 is a diagram showing a modification of the liquid container
means constituting an essential component of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1 which shows an example of the liquid-piston
type slurry pump system according to the present invention, two
valve boxes 1 and 1a of a similar construction are provided. The
valve box 1 has a suction valve 2 and a discharge valve 3, which
are connected with a suction pipe 4 and a discharge pipe 5 branched
from a main slurry pipe line 6. Likewise, the valve box 1a has a
suction valve 2a and a discharge valve 3a, which are connected to a
suction pipe 4a and a discharge pipe 5a, respectively, both being
also branched from the main slurry pipe line 6.
The slurry pump system further comprises two liquid container means
8 and 8a, each having two ports, one at the bottom and the other at
an upper side thereof, and the valve boxes 1 and 1a are connected
through pipes 7 and 7a to the bottom ports of the liquid container
means 8 and 8a, respectively. Thus, the interior of the two valve
boxes 1 an 2 and the lower halves of the liquid containers 8 and 8a
are filled with slurry X or the like introduced from the suction
pipes 4 and 4a as the pump system is operated.
The upper side ports of the liquid containers 8 and 8a are further
connected through pipes 9 and 9a to an electromagnetic changeover
valve 10 which is in turn connected through a suction pipe 12 and a
discharge pipe 13 to a pump unit 11 of, for instance, a turbine
type rotatable in a constant direction.
The upper half of each of the liquid containers 8 and 8a and the
interior of the electromagnetic valve 10 are filled with an
operating fluid Y, such as oil, which does not mix with, dissolve
in, or react with, the slurry to be pumped and has a lower specific
gravity than that of the slurry. Since the lower half of each of
the liquid containers 8 and 8a is filled with the slurry introduced
through the valve boxes 1 and 1a from the main slurry pipe line,
distinct boundary surfaces 14 and 14a are formed between the slurry
X and the operating fluid Y in the containers 8 and 8a.
In the upper parts of the liquid containers 8 and 8a, there are
provided detectors 15 and 15a for detecting variations of the
boundary surfaces 14 and 14a in the liquid containers 8 and 8a.
When any one of the boundary surfaces 14 and 14a is elevated until
it contacts the tip of the corresponding detector 15 or 15a, a
controller 16 is operated, and the electromagnetic changeover valve
10 is thereby activated as will be described more fully
hereinafter.
The slurry pump system of this example operates as follows. In the
case where the electromagnetic changeover valve 10 is so positioned
as shown in FIG. 1 that the suction pipe 12 and the discharge pipe
13 are connected with the pipes 9 and 9a, respectively, the
operating fluid Y flows from the upper part of the liquid container
8 through the pipe 9, a passage of the changeover valve 10, the
suction pipe 12, the rotary pump unit 11, the discharge pipe 13,
another passage of the changeover valve 10, and a section of pipe
9a to the upper part of the liquid container 8a as indicated by
solid line arrow marks in FIG. 1. Thus, the boundary surface 14 in
the liquid container 8 is elevated, and an additional quantity of
the slurry is sucked from the suction pipe 4 into the valve box 1
and also into the lower half part of the liquid container 8. At the
same time, the boundary surface 14a in the liquid container 8a is
lowered, so that a part of the slurry X contained in the lower part
of the container 8a is pushed out through the valve box 1a and the
pipe 7a into the discharge pipe 5a and further into the delivery
side of the main slurry pipe line 6.
When the boundary surface 14 in the container 8 is further elevated
until it contacts the tips of the detector 15, the controller 16 is
operated, and the electromagnetic changeover valve 10 is
transferred to another position wherein the operating fluid
delivered from the rotary type pump unit 11 is passed in the
direction indicated by the arrow-headed broken lines in FIG. 1, and
the boundary surface 14 is now pushed down and the boundary surface
14a is elevated in the respective liquid containers 8 and 8a. The
slurry X contained in the lower part of the container 8 is thus
driven toward the valve box 1, and a part thereof is delivered into
the discharge pipe 5 and further into the main slurry pipe line
6.
At an instant when the boundary surface 14a is elevated to a level
at which it touches the tip of the detector 15a, the controller 16
is again operated, and the electromagnetic valve 10 is thereby
switched back to its original position wherein the operating fluid
is circulated in the solid-line-arrow-marked direction shown in
FIG. 1, whereby the slurry is discharged from the valve box 1a into
the main discharge pipe line 6.
The above described operation is repeated continuously until a
desired quantity of slurry is pumped up from the suction pipes 4
and 4a and discharged into the discharge pipes 5 and 5a in an
alternate manner.
As will be apparent from the above description, the liquid-piston
type pump system of this example comprises at least a pair of valve
box-liquid container assemblies and a changeover valve. Moreover
since the operating fluid is passed through the changeover valve
alternately into the liquid containers under the control of the
controller, operable in response to the detected positions of the
boundary surfaces in the liquid containers, a pump unit of a size
and weight substantially smaller than the conventional plunger pump
unit can be used in the pumping system, whereby numerous
advantageous features as described hereinbefore can be
realized.
Another example of the liquid-piston type slurry pump system is
indicated in FIG. 2 wherein like parts as in the first embodiment
are designated by like reference numerals and characters.
This system is different from that of the first example in that a
piston-cylinder device 20 is interposed between the changeover
valve 10 and the liquid containers 8 and 8a. The piston-cylinder
device 20 comprises first and second cylinders 23 and 23a including
pistons 24 and 24a, respectively, and third and fourth cylinders 26
and 26a including pistons 27 and 27a, respectively. The pistons 24
and 27 are unitarily connected together through a rod 29, and the
pistons 24a and 27a are also connected together in a unitary manner
through another rod 29a. An end of a first pipe 21, the other end
of which is connected to one port of the changeover valve 10 having
four ports, is connected to the region above the piston 24 in the
first cylinder 23 and also to the region below the piston 24a in
the second cylinder 23a. An end of a second pipe 22, the other end
of which is connected to another port of the changeover valve 10,
is connected to the region below the piston 24 in the first
cylinder 23 and the upper side of the piston 24a in the second
cylinder 23a.
Likewise, an end of a pipe 25, the other end of which is connected
to the liquid container 8, is connected above the piston 27
included in the third cylinder 26 and also to the fourth cylinder
26a below the piston 27a. An end of a pipe 25a, and the other end
of which is also connected to the liquid container 8a, is connected
to the third cylinder 26, in the region below the piston 27 and to
the region above the piston 27a in the fourth cylinder 26a.
In the second embodiment of the invention, a reservoir 30 is
further provided on the suction side of the rotary pump unit P for
supplying the operating fluid Y through the pump unit P, changeover
valve 10, pipes 21 and 22, and through the interior of the
cylinders 23 and 23a, while another kind of operating fluid Z,
which does not mix with, dissolve in, or react with, the slurry X
to be pumped and has a specific gravity lower than that of the
slurry, is contained in the upper parts of the liquid containers 8
and 8a, interiors of the pipes 25 and 25a, and the third and fourth
cylinders 26 and 26a.
The second embodiment of the invention operates as follows. When
the changeover valve 10 is at a position for sending the operating
fluid Y in the solid-line-arrow-marked direction into the pipe 21,
the pistons 24 and 24a in the first and second cylinders 23 and
23a, respectively, are displaced downward and upward as indicated
by further solid-line-arrow marks in FIG. 2. Thus, a part of the
operating fluid at the opposite sides of the pistons 24 and 24a is
sent back through the pipe 22 and the changeover valve 10 to the
reservoir 30 on the suction side of the pump unit 11.
The downward and upward movements of the pistons 24 and 24a,
respectively, cause the pistons 27 and 27a to move downward and
upward as indicated by solid-line-arrow marks, and a part of the
intermediate operating fluid Z contained in the spaces underside
and upperside of the pistons 27 and 27a in the third and fourth
cylinders 26 and 26a, respectively, is thereby forced into the
upper part of the second liquid container 8a through the pipe 25a.
Thus, the boundary surface 14a in the second liquid container 8a is
forced down, and a part of the slurry X contained in the valve box
1a is delivered into the main slurry line 6.
On the other hand, the above-mentioned downward and upward
movements of the pistons 27 and 27a, respectively, cause the
suction of a part of the intermediate operating fluid Z from the
upper part of the first container 8 through the pipe 25 into the
spaces at the upper side and the lower side of the pistons 27 and
27a, respectively. The boundary surface 14 in the container 8 is
thereby elevated, and the slurry in the suction pipe 4 is thereby
sucked into the valve box 1 and toward the lower part of the
container 8. When the boundary surface 14 is ultimately brought
into contact with the tip of the detector 15, the controller 16 is
thereupon operated, the changeover valve 10 thus being operated,
whereby the first operating fluid Y is passed in a direction
opposite to that in the above description, as indicated by
arrow-headed broken lines.
In the second embodiment of the invention, since the
piston-cylinder device 20 is provided between the changeover valve
10 and the liquid containers 8 and 8a, any possibility of
undesirable components, such as abrasive particles and the like,
contained in the slurry being mixed with the operating fluid Y can
be completely eliminated. Furthermore, when the diameter of the
first and second cylinders differs from the diameter of the third
and fourth cylinders, the pressure and the delivery of the
liquid-piston type slurry pump system can be changed. In addition,
since the operating fluid Y is acting on the slurry through the
interposition of the second operational fluid Z of the above
specified character, the operational fluid Y may be air or steam
instead of a liquid substance, whereby a pump unit P in the form of
an air turbine or a steam turbine may also be used in such a
modification.
In FIG. 3, there is illustrated still another embodiment of the
present invention, wherein two pairs of liquid containers 18, 18a,
and 28 and 28a are added to the existing liquid containers 8 and 8a
in FIG. 1. The containers 8, 18, and 28, and 8a, 18a, and 28a are
connected in series, respectively, and three kinds of operating
fluids Y, Z.sub.1, and Z.sub.2 are used therein, so that boundary
surfaces 14, 14a, 31, 31a, 32, and 32a are formed between the
slurry and the operating fluid Z.sub.1 and between the operating
fluids Z.sub.1 and Z.sub.2, and Z.sub.2 and Y. The operating fluid
Z.sub.1 may be an oil, and the operating fluid Z.sub.2 may be, for
instance, water. The boundary surface detectors 15 and 15a are
provided in the liquid containers 28 and 28a provided in the last
stage.
In this embodiment of the invention, any possibility of the slurry
X mixing into the operating fluid Y can be completely eliminated,
and, furthermore, the possibility of the slurry X acting on the
detectors 15 and 15a can be avoided. When water is selected as the
operating fluid Z.sub.2 as described above, any trace of the slurry
X which might have intruded in the operating fluid Z.sub.2 can be
easily removed by replacing the operating fluid Z.sub.2 since
water, constituting the fluid Z.sub.2, is cheap.
* * * * *