U.S. patent number 3,682,575 [Application Number 05/096,861] was granted by the patent office on 1972-08-08 for concrete pump.
Invention is credited to Gunnar Guddal, Karl Guddal.
United States Patent |
3,682,575 |
Guddal , et al. |
August 8, 1972 |
CONCRETE PUMP
Abstract
A concrete pump comprising a pair of hydraulically actuated
concrete pumping cylinders, a hopper for receiving a supply of
concrete to be pumped, a Y-shaped fitting including a pair of
inlets and a single outlet, and a valve coacting with the concrete
pumping cylinders, the hopper and the Y-shaped fitting to control
the flow of concrete through the pump. The valve includes a valve
body and a valve spool shiftable by a single hydraulic cylinder to
alternately connect the concrete pumping cylinders to the inlets of
the Y-fitting and to the hopper.
Inventors: |
Guddal; Karl (Seattle, WA),
Guddal; Gunnar (Seattle, WA) |
Family
ID: |
22259438 |
Appl.
No.: |
05/096,861 |
Filed: |
December 10, 1970 |
Current U.S.
Class: |
417/517; 417/900;
137/625.48 |
Current CPC
Class: |
F04B
15/023 (20130101); F04B 9/113 (20130101); F04B
9/1178 (20130101); F01L 23/00 (20130101); F01L
25/08 (20130101); F04B 7/025 (20130101); F04B
9/115 (20130101); F04B 1/02 (20130101); Y10S
417/90 (20130101); Y10T 137/86879 (20150401) |
Current International
Class: |
F04B
15/00 (20060101); F04B 1/02 (20060101); F04B
15/02 (20060101); F04B 1/00 (20060101); F04B
7/00 (20060101); F01L 25/08 (20060101); F04B
7/02 (20060101); F04B 9/115 (20060101); F01L
23/00 (20060101); F04B 9/00 (20060101); F04B
9/113 (20060101); F01L 25/00 (20060101); F04B
9/117 (20060101); F04b 007/00 (); F04b 015/02 ();
F16k 011/20 () |
Field of
Search: |
;417/517,900,516,518
;137/625.33,625.34,625.48 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
T838,319/599 |
|
Feb 1956 |
|
DT |
|
1,803,819 |
|
Oct 1968 |
|
DT |
|
Primary Examiner: Walker; Robert M.
Claims
This invention is hereby claimed as follows:
1. A concrete pump comprising a hopper for receiving concrete, a
pair of concrete pumping cylinders synchronously operated to be
alternately charged with concrete and to alternately discharge
concrete therefrom, a Y-shaped discharge fitting having a pair of
inlets and a single outlet adapted to be connected to a hose, a
valve arranged between said cylinders and the inlets of said
fitting for alternately connecting each of the cylinders to said
hopper to be charged and to said inlets of said fitting to be
discharged, said valve including a valve body having a pair of
inlet ports, one communicating with each cylinder, and a pair of
outlet ports axially aligned with the inlet ports, one outlet port
communicating with each inlet of said fitting, and a valve spool
(slidably received) reciprocably movable in said valve body between
first and second positions alternately connecting one of the inlet
ports with one of said outlet ports and the other of the inlet
ports with the hopper and closing the other of the outlet
ports.
2. A concrete pump as defined in claim 1, and means for driving
said concrete pumping cylinders and said valve spool in synchronism
to cause pumping of concrete from the hopper to and through the
Y-shaped discharge fitting.
3. A concrete pump as defined in claim 1, and means for driving
said concrete pumping cylinders and said valve spool in synchronism
to cause pumping of concrete from the Y-shaped discharge fitting to
and into the hopper.
4. A concrete pump as defined in claim 1, wherein said valve body
includes front and back opposed walls, the inlet ports being in the
back wall, and the outlet ports being in the front wall, and said
valve spool including spaced front and back plates interconnected
to move together and respectively sliding against the front and
back walls of the valve body, a single opening in the front plate
adapted to be alternately in alignment with an outlet port, three
openings in the back plate, the center opening being aligned with
the opening in the front plate and the outside openings being
spaced from the center opening a distance equal to the spacing of
the valve body inlet ports, and a tubular member extending between
the plates and interconnecting the opening in the front plate with
the center opening in the rear plate.
5. A concrete pump as defined in claim 4, wherein the openings in
the spool plates are the same size as the valve body ports.
6. A concrete pump as defined in claim 4, wherein the inlet ports
and openings in the back spool plate are larger than the outlet
ports and the opening in the front spool plate, and the tubular
member is frusto-conical with the large end at the back plate.
7. A concrete pump as defined in claim 6, wherein the concrete
pumping cylinders have a larger outlet diameter than the valve
inlet ports, and a frustoconically shaped connecting pipe extends
between each cylinder and inlet port.
8. A concrete pump as defined in claim 1, wherein said valve is
positioned horizontally below the hopper and effectively defines
the bottom of the hopper, and said valve is fully open to the
hopper throughout its length.
9. A concrete pump as defined in claim 8, wherein the valve body
includes front and back opposed walls and end walls all connected
to the bottom end of the hopper and a bottom wall, the inlet ports
being in the back wall, and the outlet ports being in the front
wall, and said valve spool including spaced front and back plates
of about the same height as the front and back walls of the valve
body and interconnected to move together in sliding relation along
the bottom wall and respectively against the front and back walls
of the valve body, a single opening in the front plate adapted to
be alternately in alignment with an outlet port, three openings in
the back plate, the center opening being aligned with the opening
in the front plate and the outside openings being spaced from the
center opening a distance equal to the spacing of the valve body
inlet ports, and a tubular member extending between the plates and
interconnecting the opening in the front plate with the center
opening in the rear plate.
10. A concrete pump as defined in claim 9, wherein a bottom plate
is provided for the spool extending between and connected to the
front and back plates.
11. A concrete pump as defined in claim 9, wherein tracks are
provided in the bottom wall of the valve body in which are guidably
received the lower edge portions of the front and back spool
plates.
12. A concrete pump as defined in claim 11, and cross bars
extending between and connected to the front and back valve body
walls at the upper ends, said cross bars having tracks for guidably
receiving the upper edge portions of the front and back spool
plates.
13. A concrete pump as defined in claim 1, wherein quick disconnect
means is provided between the valve body and the concrete pumping
cylinders, and between the valve body and the Y-fitting.
14. A concrete pump as defined in claim 1, wherein means is
provided to lubricate the engaging surfaces of the valve spool and
valve body.
15. A concrete pump as defined in claim 1, wherein said valve is
positioned horizontally below the hopper, said valve body including
front and back opposed walls and top and bottom walls and end walls
all connected together to define a chamber in which the valve spool
operates in coaction therewith, the inlet ports being in the back
wall, the outlet ports being in the front wall, a pair of concrete
supply ports in the top wall aligned with the inlet and outlet
ports, said hopper including a bottom wall having a pair of
discharge ports, and connecting pipes between the discharge ports
and the supply ports.
16. A concrete pump as defined in claim 1, wherein each of said
concrete pumping cylinders includes a cylindrical casing having a
piston slidable therein between opposite ends thereof and connected
to a piston rod, and means for driving the pistons of said concrete
pumping cylinders including hydraulic cylinders axially aligned
therewith, each of said hydraulic cylinders including a cylindrical
casing having a piston slidable therein between opposite ends and
connected to a piston rod of said concrete pumping cylinder.
17. A concrete pump as defined in claim 1, wherein each of said
concrete pumping cylinders includes a cylindrical casing having a
piston slidable therein between opposite ends thereof, means for
driving the pistons of said concrete pumping cylinders including a
driving hydraulic cylinder including a cylindrical casing having a
piston slidable therein between opposite ends thereof and connected
to a piston rod, a power cylinder including a cylindrical casing
having a piston slidable therein and connected to the piston rod of
said driving hydraulic cylinder, a fluid connection from each end
of said power cylinder, one to each of said concrete pumping
cylinders, means connecting the pistons of the concrete pumping
cylinders so they move in opposite directions, and hydraulic fluid
in the power cylinder and concrete pumping cylinders, whereby
operation of the power cylinder causes alternate movement of the
pistons in the concrete pumping cylinders.
18. A concrete pump as defined in claim 1, wherein wear plates are
provided on the engaging surfaces of the spool and valve body.
19. A concrete pump as defined in claim 1, wherein wear rings are
provided at the inlet and outlet ports of the valve body.
Description
This invention relates in general to a concrete pump for pumping
concrete from a source to a nozzle, or for pumping concrete to
transport the concrete from one location to another, and more
particularly to a concrete pump capable of pumping both wet and dry
concrete, and still more particularly to a concrete pump having a
single movable valve spool for controlling concrete flow
therethrough, although the pump may also be used to pump other
dense and difficult to move fluid materials.
Heretofore, there have been several concrete pumps developed, none
of which could pump anything but wet concrete. For example, it has
only been possible to pump concrete having a 3 to 4 inch slump with
pumps heretofore known, while the pump of the invention can pump
concrete having a 1 inch slump, this being much drier. It should
also be recognized that the pump of the present invention can pump
wetter concrete with more efficiency than heretofore known pumps.
One of the problems of pumps already known lies in the fact that
the concrete must move through sharp angles and narrow openings to
enter the inlet side of the pump. Another problem with heretofore
known pumps is the need to use a plurality of valving members and
hydraulic cylinders for operating the valving members in order to
accomplish pumping action. For example, one known pump utilizes
four independent valves each independently powered by a hydraulic
cylinder in order to accomplish the desired flow of concrete
through the pump. Another known pump utilizes a flipper valve
arrangement which necessitates bending the concrete around sharp
corners to flow through the pump. It is not possible for dry
concrete to easily bend around sharp corners.
The pump of the present invention obviates the heretofore known
difficulties and enables relatively dry concrete to be pumped, such
as concrete having as low as one inch slump. The pump of the
invention includes a valve having a valve body and a valve spool
shiftable therein and powered by a hydraulic cylinder. The valve
body includes a pair of inlet ports to which are connected concrete
pumping cylinders, a pair of outlet ports aligned with the inlet
ports and having a Y-fitting connected thereto, wherein the
Y-fitting includes a pair of inlets and a single outlet. The valve
spool is movable within the valve body to coact with the inlet and
outlet ports and thereby control movement of concrete therethrough.
The valve spool includes a pair of opposed plates, one coacting
with the inlet ports of the valve body and the other coacting with
the outlet ports. The plate coacting with the inlet ports includes
three openings, while the plate coacting with the outlet port
includes a single opening. The tubular member extends between the
single opening of the one plate and the center opening of the other
plate. One of the openings in the plate having three openings, and
the center opening is aligned with the inlet ports of the valve
body during each of the two positions into which the valve spool
may move. Accordingly, the opening in the other plate and common to
the tubular member extending between the plates is alternately in
communication with one or the other of the inlets to the Y-fitting,
and therefore one of the outlet ports to the valve body is always
closed to the hopper and valve spool, while the other is always
open to the tubular member. With respect to the plate having three
openings, the opening on either side of the center opening is
either connected to a pumping cylinder and a hopper or is not being
used. It can therefore be recognized that a single movable valve is
arranged in a valve body for effecting flow control of concrete
into the Y-fitting. Suitable hydraulic and electrical controls are
provided for synchronously operating the concrete pumping cylinders
and the valve spool. The capacity of the pump may be easily changed
by changing the capacity of the concrete pumping cylinders.
It is therefore an object of the present invention to provide a new
and improved concrete pump.
Another object of the invention is in the provision of a concrete
pump that is simple in construction in that it has a low number of
parts, and which is easily convertible for changing its capacity,
and which is constructed to minimize leakage of concrete.
Another object of the present invention is in the provision of a
concrete pump capable of pumping relatively dry concrete, such as
concrete having as low as one inch slump.
Other objects, features, and advantages of the invention will be
apparent from the following detailed disclosure, taken in
conjunction with the accompanying sheets of drawings, wherein like
reference numerals refer to like parts, in which:
FIG. 1 is a perspective view of the concrete pump according to the
invention mounted on a trailer;
FIG. 2 is a top plan view of the essentially mechanical components
of the concrete pump, with some parts broken away and other parts
shown in dotted lines for purposes of clarity;
FIG. 3 is an enlarged partially fragmentary and broken view taken
substantially along line 3--3 of FIG. 2 showing some parts in
vertical section and other parts in side elevation;
FIG. 4 is an enlarged fragmentary sectional view taken
substantially along line 4--4 of FIG. 7 through the valve with the
valve spool omitted;
FIG. 5 is a broken, partly sectional and partly side elevational
view taken substantially along line 5--5 of FIG. 7;
FIG. 6 is a top plan view of a stud or pin employed for providing
quick detachable coupling of the pumping cylinders and
Y-fitting;
FIG. 6a is a vertical sectional view taken through one of the studs
mounted on the valve and illustrating a part anchored by a pin in
phantom, and taken substantially along line 6A-- 6A of FIG. 6;
FIG. 7 is a broken horizontal sectional view taken through the
valve body of the valve embodiment shown in FIG. 3;
FIG. 8 is a partly diagrammatic, partly horizontal sectional view
taken through the valve of FIG. 3 and illustrating the position of
the movable parts when the valve spool is in one position;
FIG. 9 is a view similar to FIG. 8 but illustrating the valve spool
in the other position and also showing the movable parts as they
are moved to the corresponding position;
FIG. 10 is a schematic diagram of a hydraulic circuit for actuating
the concrete pumping cylinders;
FIG. 11 is a broken and partly sectional view of a hydraulic
cylinder employed for powering a concrete pumping cylinder, and
illustrating the limit switch arrangement;
FIG. 12 is a schematic diagram of the hydraulic circuit for
operating the valve spool of the valve;
FIG. 13 is an electrical schematic diagram for the solenoid
actuated hydraulic valves that drive the concrete pump of the
invention;
FIG. 14 is a transverse sectional view taken through a modified
valve wherein the spool includes a bottom wall;
FIG. 15 is a longitudinal vertical sectional view, partly broken,
and of the valve embodiment of FIG. 10, and taken substantially
along line 15--15 of FIG. 14;
FIG. 16 is a transverse sectional view taken through a still
further modified valve according to the invention;
FIG. 17 is a horizontal sectional view taken through a further
modification of the invention and illustrating a tapered tube in
the valve spool;
FIG. 18 is a front elevational view of a further modification of
the invention illustrating the hopper and valve arrangement;
FIG. 19 is a top plan view of the hopper taken substantially along
line 20--20 of FIG. 18;
FIG. 20 is a fragmentary enlarged sectional view taken
substantially along line 20--20 of FIG. 18, showing the valve spool
in one position;
FIG. 21 is a fragmentary enlarged sectional view taken
substantially along line 21--21 of FIGS. 18 and 20;
FIG. 22 is a fragmentary enlarged sectional view taken
substantially along line 22--22 of FIG. 20;
FIG. 23 is a generally diagrammatic and somewhat sectional view of
a further modified concrete pumping cylinder drive arrangement and
illustrating the parts in one position; and
FIG. 24 is a view similar to FIG. 22 but illustrating the parts in
another position.
Referring now to the drawings, the concrete pump of the invention
is preferably mobilized to facilitate movement from one location to
another, and it therefore may be mounted on a trailer or on a truck
chassis. Mounting of the pump on a trailer is illustrated in FIG.
1. The pump generally includes a pair of concrete pumping cylinders
26 and 27, a hopper 28, a Y-fitting 29, and a valve 30. The
concrete pumping cylinders 26 and 27 are respectively driven by
reciprocating hydraulic motors 31 and 32 in the form of hydraulic
cylinders, while the valve 30 is controlled by a hydraulic motor 33
in the form of a hydraulic cylinder. An engine 34 drives one or
more hydraulic pumps 35 which supplies fluid power to the hydraulic
cylinders 31, 32 and 33.
Concrete is suitably supplied to the hopper 28, and operation of
the concrete pumping cylinders 26 and 27 and the valve 30 causes
the concrete pumping cylinders to be alternately charged with
concrete and to discharge concrete. Discharge of concrete is
alternately made to one of the sides of the Y-fitting 29 which is
suitably connected to a flexible or rigid pipe 36, that may
terminate in a nozzle 37 for the pneumatic application of concrete
in a wall system or the like. Compressed air may also be supplied
to the nozzle for facilitating discharge of concrete therefrom. It
should be appreciated that the concrete pump may merely be used to
transport concrete from one location to another. More specific
operation of the pump will be hereinafter set forth in connection
with the hydraulic circuits which control the hydraulic cylinders,
as seen in FIGS. 10 and 12, and the synchronization of the
cylinders by means of a suitable electrical circuit and switching
arrangement as seen in FIG. 13.
The valve 30, details of which are illustrated in FIGS. 3, 4, 5 and
7 to 9, includes generally a valve body 40 and a valve spool 41.
The valve is positioned below the hopper 28, so that concrete is
fed to the valve and the valve controls the flow of concrete to the
Y-fitting 29. In order to facilitate the movement of concrete from
the hopper into the valve, since the hopper is tapered toward the
bottom, an agitator 42 is positioned just above the valve 30 within
the lower end of the hopper, and it is defined by a shaft 43
extending cross-wise of the hopper and bearingly supported in
opposed hopper walls, and a plurality of fingers or tines 44 which
extend from the shaft, and which are capable of moving through the
concrete to maintain it in mixed form and flowable at the inlet to
the valve 30. A suitable rotatable fluid motor 45, FIG. 2, may be
mounted on one end of the hopper and drivingly connected to the
agitator shaft 43 to provide rotating power to the agitator. The
fluid motor 45 may be driven from the source of the pressurized and
hydraulic fluid developed by the pump 35.
The valve body 40 of the valve 30 includes a bottom wall 47, front
and back walls 48 and 49, and opposite end walls 50 and 51, all
arranged together to define a rectangularly shaped chamber in which
the valve spool 41 is received. As seen particularly in FIG. 7, the
front wall of the valve body is provided with a pair of outlet
ports 52 and 53, while the back wall 49 is provided with inlet
ports 54 and 55, it being appreciated that the outlet port 52 and
the inlet port 54 are aligned, while the outlet port 53 and the
inlet port 55 are aligned.
The outlet ports 52 and 53 are connected to the Y-fitting 29,
wherein the Y-fitting includes a pair of legs or inlets 56 and 57
merging into a single leg or outlet 58. Thus, the legs 56 and 57
become inlet members to the leg 58, the latter of which becomes an
outlet or discharge member. A single flange 59 provided at the
inlet ends of legs 56 and 57 defines a mounting flange for mounting
the Y-fitting to the valve front wall 48, and in this connection,
the flange 59 is provided with a plurality of stud holes 60 which
are received on studs 61 carried by the front wall 48.
As seen in detail in FIGS. 6 and 6a, each stud 61 is provided with
a threaded portion 62 at one end which is adapted to be received in
a threaded hole 63 of the valve body front wall 48. Each stud is
provided with a pin opening 64 that is adapted to receive a
removable pin 65 which serves to lock the flange 59 in place
tightly against the valve body wall 48. Any suitable gasket may be
provided between the Y-fitting flange and wall if desired to
eliminate leakage and enhance the sealing relation between the
flange and valve body. The pin and stud arrangement enables quick
disconnect and quick connect of the Y-fitting to the valve 30.
During disconnection, the pins would be driven free and removed
from the pin openings so that the flange and Y-fitting could easily
be pulled from the studs. Similarly, when mounting the Y-fitting
and flange onto the valve body, following the positioning of the
flange onto the studs, the pins are inserted into the pin openings
and driven into tight engagement to firmly fix the Y-fitting in
place on the valve body. Accordingly, Y-fittings of various sizes
can be easily substituted, and in the event of any clogging
problems, the Y-fitting may be quickly and easily removed to enable
cleaning and unclogging.
The concrete pumping cylinders 26 and 27 are similarly detachably
fastened to the valve body 40, wherein the pumping cylinders are
respectively provided with mounting flanges 68 and 69. Each pumping
cylinder mounting flange includes a plurality of stud holes for
receiving studs 70 that are secured to the back wall 49 of the
valve body. Removable pins 71 are received in pin openings in the
studs, which pins are hammered into position or removed as the case
may be when mounting or demounting of the pumping cylinders to the
valve body. Accordingly, the pumping cylinders may easily be
exchanged for replacements or cylinders of different capacity.
Again, suitable gaskets may be provided between the valve wall and
mounting flanges to seal against leakage. The pumping cylinders 26
and 27 will of course be in alignment with the inlet ports 54 and
55, while the legs 56 and 57 of the Y-fitting 29 will be in
alignment with the outlet ports 52 and 53. Moreover, in the event
of maintenance requirements for the pumping cylinders, they may
easily be disengaged from the valve body.
The valve spool 41 may take many forms, but in the embodiment of
FIGS. 1 to 9, includes front and back plates 74 and 75 of about the
same height as the front and back walls of the main valve body, but
of much shorter length in order to facilitate movement within the
valve body. The front plate 74 includes a single opening 76, while
the back plate 75 includes three openings 77, 78 and 79. The
centers of the openings are at the same level as the centers of the
inlet and outlet ports of the valve body. The central opening 78 in
the back plate 75 is aligned with the opening 76 in the front plate
74, and a tubular member 80 extends between these openings and is
suitably secured to the front and back plates, such as by welding,
so that the front opening 76 and the rear central opening 78 are
always in communication with each other. The outside rear openings
77 and 79 are spaced from the central opening 78 a distance equal
to the spacing between the inlet ports 54 and 55 of the valve body,
whereby alignment of the rear central opening 78 with one or the
other of the inlet ports will cause the alignment of one or the
other of the rear openings 77 and 79 with the other inlet port.
The front and rear plates 74 and 75 of the valve spool 41, are of
the same length and aligned with each other, and maintained in
alignment by the tubular member 80, and a plurality of connecting
cross bars 81, FIGS. 2 and 3, so that the front and back plates
maintain their proper position in slidable relation against the
front and back walls of the valve body and move together upon being
shifted from one position to the other as illustrated in FIGS. 8
and 9.
Wear plates 82 of hardened steel, FIG. 3, are epoxy glued to the
engaging faces of the spool and valve body to provide long wear.
They may be replaced by melting the glue and installing new
plates.
In order to facilitate maintenance and to enable changing capacity
of the valve, wear rings 83, FIGS. 8 and 9, may be provided for the
inlet and outlet ports of the valve body, which wear rings may
easily be replaced when necessary, or may be exchanged for wear
rings of different size to change the inlet and outlet port size.
The wear rings are merely held in place by the flanges of the
pumping cylinders and Y-fittings, and the front and back plates of
the valve spool. When changing the capacity of the valve, a sleeve
may be inserted in the tubular member 80 to coact with the size of
the wear rings. Therefore, to change the capacity, it is only
necessary to change the size of the rear rings, utilize a sleeve in
the tubular member 80, and change the size of the concrete pumping
cylinders.
The valve spool 41 is shifted between two positions shown in FIGS.
8 and 9 by the reciprocating fluid motor 33 in the form of a
hydraulic cylinder which includes a cylinder 85 having a piston 86
therein and secured to a piston rod 87. The hydraulic cylinder 33
is double acting and may be operated by alternately connecting
pressure and exhaust lines to the fluid lines 88 and 89 at opposite
ends of the cylinder 85. The piston rod 87 is movable through a
sealed opening 90 in end wall 50 of the valve body, and is
connected at its terminal end to a fitting 91, FIGS. 8 and 9, which
is in turn suitably connected to the tubular member 80 of the valve
spool. Thus, actuation of the hydraulic cylinder 33 will produce
shifting of the valve spool 41 between the positions shown in FIGS.
8 and 9, wherein the concrete pumping cylinders are alternately
connected to the hopper so they can be charged with concrete and to
one of the Y-fitting legs so that the charge can be pumped through
the Y-fitting 29. As seen in FIG. 8, the pumping cylinder 26 is in
its pumping or discharge stroke, and therefore in communication
with the inlet leg 56 of the Y-fitting 29 through the alignment of
the inlet port 54, the rear opening 78 in the valve spool, the
tubular member 80, the front opening 76, the outlet port 52, and
the Y-fitting leg inlet 56, while the other pumping cylinder 27 is
in communication with the hopper and during it suction stroke will
draw concrete into the cylinder through the rear opening 77 in the
valve spool and the inlet port 55 of the valve body. Conversely,
when the concrete pumping cylinders are making the opposite stroke,
the pumping cylinder 26 is sucking concrete and being charged,
while the pumping cylinder 27 is pumping concrete through the
tubular member 80 of the valve spool and into the Y-fitting inlet
leg 57, and during this cycle, the outlet port 52 is closed to the
hopper. Similarly, during the previous cycle as shown in FIG. 8,
the outlet port 52 is closed to the hopper by the front plate 74 of
the valve spool. Therefore, it can be appreciated that while the
outlet ports 52 and 53 of the valve body are alternately connected
to the concrete pumping cylinders, they are likewise alternately
closed by the valve spool.
In order to facilitate cleaning of the valve 30, following the use
of the pump, which may be accomplished by feeding water to the
hopper and pumping it through the pumping cylinders and the
Y-fitting, a drain and clean out plug 92 may be provided in the
bottom wall 47 of the valve body. While not necessary, the
Y-fitting 29 may also be removed during cleaning. Further, as will
be hereinafter explained, the pump may be placed in reverse to draw
water through the Y-fitting and back into the valve and hopper in
order to expedite cleaning.
The pumping cylinders 26 and 27 operate opposite to each other,
that is, when one of the pumping cylinders is in the pumping cycle,
the other is in the suction cycle. The pumping cylinder 26 includes
a piston 95 slidable therein and connected to a piston rod 96,
while the pumping cylinder 27 includes a piston 97 connected to a
piston rod 98.
The hydraulic circuitry employed for operating the hydraulic
cylinders 31 and 32 which in turn power the concrete pumping
cylinders 26 and 27 is illustrated in FIG. 10. The piston rod 96 of
the pumping cylinder 26 is connected directly to the piston 100
operable in the hydraulic cylinder 31, while the piston rod 98 of
the pumping rod 27 is connected directly to the piston 101 operable
in the hydraulic cylinder 32. Suitable seals will be provided for
the piston rods 96 and 98 to prevent leakage from the concrete
pumping cylinders or from the hydraulic drive cylinders, and a
lubrication box 102, FIGS. 2 and 3, may be provided between the
hydraulic drive cylinders and the concrete pumping cylinders to
provide lubrication for the piston rods.
A four-way solenoid operated hydraulic control valve 103
alternately connects the blind ends of the hydraulic cylinders 31
and 32 to pressure and exhaust to alternately cause the concrete
pumping cylinders to move through charge and discharge cycles.
Lines 104 and 105 respectively connect the blind ends of the
hydraulic cylinders 31 and 32 to control valve 103 which is also
connected to pressure and exhaust or drain lines 106 and 107. The
pump 35 in reality includes two stages, one of which is used to
handle the hydraulic circuitry for the concrete pumping cylinders,
and is designated 35a and the other of which is used for hydraulic
circuitry handling the shifting of the valve spool 41 and which is
designated 35b. The inlet end of the pump 35a is connected to the
reservoir or tank 108, while the outlet or pressure side is
connected to the pressure line 106. The rod ends of the hydraulic
cylinders 31 and 32 are connected in common by line 109, which line
is also connected through a pressure responsive valve 110 to tank
108. Accordingly, the hydraulic fluid on the rod ends of the
pistons in the hydraulic cylinders 31 and 32 is forced back and
forth between the hydraulic cylinders by the pressure applied to
the blind end sides of the pistons. Inasmuch as leakage will be
experienced, the excess fluid at the rod ends of the pistons can be
returned to tank through opening of the pressure responsive or
overload valve 110 when the pressure in the common line 109 exceeds
the set point of the valve 110.
The hydraulic circuitry for controlling the shifting of the valve
spool 41 is illustrated in FIG. 12, wherein a four-way solenoid
operated hydraulic control valve 112 alternately connects the rod
and blind side of the piston 86 to pressure and tank. Lines 113 and
114 connect the control valve 112 to the valve spool hydraulic
cylinder 33. Inasmuch as a quick and positive shifting of the spool
41 is desired, an accumulator 115 is provided for feeding
pressurized fluid through the control valve 112 to the hydraulic
cylinder 33. The accumulator is charged by a pump 35 through a
pressure line 116. The suction side of the pump is connected to
tank 117 through suction line 118. When the desired pressure is
reached in the accumulator, an unloading valve 119 will be actuated
to connect the pressure line 116 back to tank while maintaining the
pressure in the accumulator. A tank line 120 is connected to the
control valve 112. Thus, operation of the control valve 112 will
cause shifting of the valve spool 41 through the operation of the
hydraulic valve cylinder 33.
Electrical circuitry for synchronizing the operation of the pumping
cylinders and the valve spool is illustrated in FIG. 13. It should
be appreciated that any type of electrical circuitry may be
provided, and further that any type of hydraulic circuitry may be
employed, and that what is illustrated is typical. Each of the
solenoid actuated control valves 103 and 112 include a pair of
solenoids designated respectively as 103A, 103B, 112A and 112B. The
circuitry of FIG. 13 includes a start switch 122, a stop switch
123, relays 124, 125 and 126, normally open limit switches 127 and
128, and a forward-reverse switch 129. The limit switches 127 and
128 are mounted on the hydraulic cylinders 31 and 32 which power
the concrete pumping cylinders 26 and 27. A typical mounting
arrangement is shown in FIG. 11 in connection with hydraulic
cylinder 31, wherein a collar 130 is provided on the common piston
rod 96 to engage and drive a movable pin 131 and actuate the limit
switch 127. A similar arrangement would be provided for the
hydraulic cylinder 132 to actuate the limit switch 128 at the end
of the pumping cycle for the respective concrete cylinder.
Power is supplied to the circuitry through terminal points 132 and
133. The stop switch 123 is normally closed while the start switch
122 is normally in open position. Momentary pressing of start
switch 122 energizes relay 124 to close contacts 124a and thereby
bypass the start switch 122 and hold relay 124 in energized
condition. Depressing of the start switch 122 also bypasses limit
switch 127 to energize relay 125 and cause closing of contacts
125a, 125b, 125c and opening of contacts 125d. Closing of the
contacts 125a causes shifting of the control valve 103 to cause
actuation of the cylinder 32 and concrete pumping cylinder 27
through its pumping cycle. The forward-reverse switch 129 is in the
forward position as illustrated. Closing of contacts 125b causes a
shifting of the valve spool 41 to the position whereby the pumping
cylinder 27 is in communication with one side of the Y-fitting to
pump concrete therethrough. Closing of contacts 125c causes holding
of relay 125 through normally closed contacts 126c, while opening
of normally closed contacts 125d prevents any possible actuation of
relay 126 until the limit switch 128 is closed. Upon closing of
limit switch 128 by the piston rod in cylinder 32, relay 126 is
energized causing opening of normally closed contacts 126c and
deenergization of relay 125. Further, energization of the relay 126
causes closing of contacts 126a to operate the control valve 103
and apply pressure to the blind end of the hydraulic cylinder 31
while connecting the blind end of the hydraulic cylinder 32 to tank
thereby causing the pumping cylinder 26 to move through a pumping
stroke while the pumping cylinder 27 will move through a suction
stroke. At the same time, contacts 126b are closed to operate
control valve 112 and shift the valve spool 41 so that the pumping
cylinder 26 is placed in communication with the Y-fitting while the
pumping cylinder 27 is placed in communication with the hopper.
When the hydraulic cylinder 31 reaches the end of its forward
travel, it will close limit switch 127 to energize relay 125 and
cause deenergization of relay 126 and reverse the hydraulic control
valves to cause reversal of the spool valve position and reverse
movement of the concrete pumping cylinders. The cycling continues
as the limit switches are alternately closed. Pumping is stopped
upon opening the stop switch 123 and deenergizing relay 124 and the
other one of the relays that is energized. By actuating the
forward-reverse switch 129 to take the position opposite from that
of FIG. 13, the relative cycling of the valve spool 41 and the
pumping cylinders 26 and 27 are reversed to cause the pumping
action from the Y-fitting back into the hopper.
The valve for controlling the flow of concrete between the hopper,
the concrete pumping cylinders and the Y-fitting may take other
forms than that shown in the embodiment of FIGS. 1 to 9 without
changing the concrete flow path. It should be appreciated that the
valve of the embodiment of FIGS. 1 to 9 is such that it is open at
the top directly to and in communication with the lower end of the
hopper so as to facilitate movement of concrete into the valve. In
this respect, the valve defines the hopper bottom. Once the
concrete is in the valve, it need only be sucked into one of the
concrete pumping cylinders, and thereafter discharged along a
straight path from the concrete cylinder through the valve spool
tubular member 80 and into the Y-fitting. It should be appreciated
that the concrete does not have to flow around corners in passing
between the hopper and pumping cylinders, for it first
gravitationally flows directly into the valve spool and then is
drawn directly into one of the concrete pumping cylinders. This
feature enhances the efficiency of the concrete pump and enables it
to easily pump concrete of low slump.
The valve illustrated in FIGS. 14 and 15, and generally designated
137 differs from that shown in FIGS. 1 to 9 only in that the valve
spool 138 includes a bottom plate 139 arranged between the front
and back plates 140 and 141 so that the valve spool is further
reinforced. Cross bars 142 additionally hold the front and back
walls in spaced apart relation, as will the tubular member 143. The
valve spool is slidably received in the valve body 144, the latter
of which is of the same construction as the valve body 40 in the
embodiment of FIGS. 1 to 9. Similarly, the hopper 145 together with
the Y-fitting 146 and the pump cylinders 147 are the same as in the
first embodiment. Likewise, the piston rod 148 is connected at one
end to the tubular member 143 and associated with a reciprocating
fluid motor for shifting the valve spool within the valve body. The
front and back plates 140 and 141, as well as front and back walls
of the valve body are provided with the same openings as in the
first embodiment. Similarly, the end edges of the front and back
plates as well as the bottom plate of the valve spool are tapered
to facilitate movement through the concrete received in the valve.
The operation of a concrete pump having the valve of this
construction is identical to that of the embodiment of FIGS. 1 to
9.
The embodiment of FIG. 16 illustrates a variation in valve
construction, wherein the valve is designated by the numeral 150
and includes a valve body 151 within which is slidably arranged a
valve spool 152. The valve body includes front and back walls 153
and 154, and a bottom wall 155. The front and back walls are on the
outer edges of the bottom wall. A plurality of cross bars 156
extends across the front and back walls at the upper end. Both the
bottom wall and the cross bars are held in place by elongated
fastening bars 157. The valve spool 152 includes front and back
plates 158 and 159, separated by a tubular member 160. As in the
other embodiments, the front and back walls of the valve body, and
the front and back plates of the valve spool include ports and
openings in the same positions. The lower edges of the front and
back plates of the valve spool are slidably received in
longitudinally extending tracks or grooves 161 and 162 formed in
the bottom wall 155 of the valve body, while the upper ends of the
plates are slidably received in tracks or grooves 163 and 164
formed in the cross bars 156, thereby guidably arranging the valve
spool within the valve body. Normally, the cement of the concrete
provides sufficient lubrication for the engaging surfaces of the
valve spool and the valve body. However, when the pump is being
cleaned, it may be necessary to provide further lubrication, and in
that event, grease or the like may be introduced to the engaging
surfaces of the valve spool and valve body by means of grease
fittings 165 and 166. Any number of grease fittings may be provided
along the valve body for admitting grease to the areas needing
lubrication. The operation of the valve shown in FIG. 16, relative
to the flow of concrete from the hopper 167 into the pumping
cylinders 168 and out the Y-fitting 169 is the same as in the
embodiment of FIGS. 1 to 9.
Another form of valve and pumping cylinder variation is illustrated
in FIG. 17, wherein the structure is intended to permit greater
pumping capacity, while at the same time maintaining compactness of
the pump by maintaining a relatively short stroke on the pumping
cylinders and maintaining a relatively short length on the valve,
this being important from the standpoint of providing a concrete
pump that can be easily transported. The valve of this embodiment
is generally designated as 172, and includes a valve body 173
within which a valve spool 174 is respectably arranged. The valve
body includes a front wall 175 having outlet ports 176, and a back
wall 177 having inlet ports 178. A Y-fitting 179 is secured to the
front wall 172 in the same fashion as before mentioned, while
pumping cylinders 180 and 181 are secured to the back wall in the
same fashion as heretofore mentioned. The valve spool 174 includes
a front plate 182 having a single opening 183, and a back plate 184
having openings 185, 186 and 187. The inlet and outlet ports of the
valve body are sized differently as illustrated in FIG. 17 wherein
the inlet ports 178 are larger than the outlet ports 176.
Similarly, the valve spool openings 185, 186 and 187 in the back
plate are larger than the valve spool openings 183 in the front
plate. Accordingly, the velocity of concrete flow into the pumping
cylinders is lower than the velocity of concrete flow into the
fitting 179.
The tubular member 188 extending between the front and back plates
of the valve spools is frusto-conical in shape wherein it has a
larger inlet end than outlet end, the inlet end being at the back
plate of the spool. Further, the pumping cylinders include cylinder
walls 180a and 181a within which the pistons 180b and 181b
reciprocate, and the outlet ends of the cylinders are connected to
the valve body by frusto-conically shaped pipe sections 189 and
190, wherein the inlet ends of the sections are larger than the
outlet ends.
This embodiment is important where it is desired to increase the
capacity of the concrete pump wherein the tapered tubular member
188 and the tapered pipe sections 189 and 190 permit larger pumping
cylinders to be used without increasing the length of the pumping
cylinders as would be necessary if the same size pumping cylinders
would be employed. Further, the length of the valve need not be as
long as it would have to be if the openings and ports were of a
size equal to that of the pumping cylinders. It is important that
the distance between the adjacent edges of the inlet ports 178 of
the valve body be such that the discharge end of the tubular member
188 at the front plate of the valve spool be closed prior to the
inlet end of the tubular member at the back plate but opened to the
next pumping cylinder to prevent backflow of concrete from the
Y-fitting into hoppers.
The embodiment of FIGS. 18-22 illustrates another form of the
invention wherein the valve spool of the valve is not open directly
to the hopper throughout its length, but communicates with the
hopper through pipe sections. The valve, generally designated by
numeral 193, includes a valve body 194 within which the valve spool
195 is reciprocably positioned. The valve spool 195 includes a
front plate 196f in spaced relation from a back plate 196b, top and
bottom plates 196t and 196l, and end plates 196d and l96e. Three
openings 197a, 197b and 197c are provided in the back plate 196b,
and two openings 198a and 198b are provided in the front wall 196f.
Openings 197a and 197b in the back plate align with openings 198a
and 198b, and tubular members 199a and 199b respectively extend
therebetween. The center opening 197c communicates with an elbow
200 that also communicates with an opening 200a in the top plate
196t.
The valve body 193 includes front and back walls 201 and 202, a
bottom wall 203, and a top wall 204, all arranged in box form, and
closed at opposite ends by end walls 205 and 206. Inlet openings to
the valve 193 are provided in the top wall by openings 207 and 208,
FIG. 20, which are in communication with outlet openings 209 and
210 formed in the bottom wall 211 of the hopper 212, by means of
connecting pipes 213 and 214. The inlet openings 207 and 208 in the
valve are aligned with the inlet and outlet ports of the valve
body, whereby charging of the concrete pumping cylinders is
facilitated. The operation of the pump of this embodiment is
essentially the same as that of the other embodiments, wherein the
pumping cylinders are alternately charged with concrete and then
discharge the concrete through a tubular member of the valve spool
and the outlet Y-fitting 216.
A variation for driving the concrete pumping cylinders is
illustrated in the embodiment of FIGS. 23 and 24, wherein the
pumping cylinders 220 and 221 have their pistons 222 and 223
interconnected by a flexible cable 224 which extends through the
rod ends of the cylinders and over a guide 225. Hydraulic fluid is
pumped from a power cylinder 226 into one or the other of the
pumping cylinders 220 and 221 against the cable sides of the
pistons, and the power cylinder is actuated by a further hydraulic
cylinder 227. The power cylinder 226 includes a cylinder 228, one
end of which is in communication with the pressure chamber of
concrete pumping cylinder 220 by means of a line 229, and the other
end of which is in communication with the pressure chamber of the
concrete pumping cylinder 221 through a line 230. A piston 231 is
slidable within the cylinder 228 and provided with a piston rod 232
that is connected to the piston 233 of the hydraulic drive cylinder
227. The piston 233 of the drive cylinder 227 is slidably received
within a cylinder 234 which is in a suitable hydraulic circuit for
causing synchronized operation of the pumping cylinders. The
hydraulic circuitry for the drive cylinder 227 is completely
independent from the hydraulic circuitry for the power cylinder 226
and the concrete pumping cylinders, whereby the hydraulic fluid
operating the drive cylinder 227 will not mix with that operating
the power cylinder 226. Therefore, any possible leakage across the
pistons of the concrete pumping cylinders, while going into the
hydraulic fluid of the circuitry driving the pumping cylinders,
will not affect the hydraulic circuitry for the drive cylinder
227.
In operation, as seen in FIG. 23, where the power cylinder piston
231 is driven downwardly, it pressurizes the fluid in the lower end
of the cylinder and drives it into the pumping cylinder 220 to
force the piston 222 downwardly to pump the concrete therefrom.
Forcing the piston 222 through the pumping cycle will cause the
piston 223 and the pumping cylinder 221 to go through the return
stroke by the cable connection between the pistons and cause the
pumping cylinder 221 to be charged with concrete. However, it
should be appreciated that the vacuum created at the head end of
each piston during operation of power cylinder 226 will retract the
piston. Yet the connection of the pistons by cable 224 provides a
more positive retraction. The low pressure fluid in the pumping
cylinder 221 will be driven back into the power cylinder 226 on the
low pressure side of the piston 231. The opposite movements of the
pumping cylinder are effected upon driving the piston 231 of the
power cylinder in the upward direction as illustrated in FIG. 24.
The size of the power cylinder 226 may be relatively large so that
it has a short stroke, thereby making it more compact.
This embodiment illustrates how the overall length of the concrete
pumping cylinder can be reduced by directly driving the pumping
cylinders rather than driving same with hydraulic cylinders as in
the other embodiments.
It will be understood that modifications and variations may be
effected without departing from the scope of the novel concepts of
the present invention, but it is understood that this application
is to be limited only by the scope of the appended claims.
* * * * *