Note: Descriptions are shown in the official language in which they were submitted.
104~}005
The invention relates to a high-pressure plunger pump having a
centrally arranged pressure valve, and a sleeve-like element mounted slidably
between the cylinder and the plunger, subjected to spring pressure, and
enclosing the pump pressure chamber.
In one known pump of this kind, the suction-valve element is
guided externally by the cylinder, which means that at high pressures there
is a danger of the suction-valve element jamming in the cylinder. In addi-
tion to this, there is an accumulation of heat in the transition area between
the suction-valve element and the cylinder wall. This known suction-valve
element must be machined internally and externally.
It is the purpose of the invention to design a high-pressure plunger
pump of the type mentioned above in a manner such that the efficiency is in-
creased, the reliability is improved, and the structure is simplified.
According to the invention, there is provided a high pressure
plunger pump having a pumping unit comprising: a housing defining a suction
chamber with an open end; a pump head extending over and closing the open
end of the suction chamber, the pump head and housing engaging one another
along a dividing plane; a retainer for securing said head to said housing;
a pressure valve in the pump head, having an inlet opening in said dividing
plane and a valve element normally closing said opening, an end face of the
valve element lying lsubstantially in said dividing plane; a collector
chamber in the pump head communicating with the suction chamber through the
pressure valve; a plunger mounted in said housing for reciprocation within
the suction chamber, the plunger being concentrically arranged relative to
the pressure valve inlet opening and valve element and having a forward dead
centre position in which a forward face of the plunger is disposed sub-
stantially in said divisional plane; a sleeve like suction valve element
carried on said plunger for sliding movement thereon and spring biased to a
closed position where an annular forward end face of the suction valve ele-
ment is engaged with a suction valve seat on the pump head, lying in the
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dividing plane and surrounding the pressure valve inlet opening.
Since the suction-valve element is guided on the plunger, the
outer surface of the element re~uires no machining. It is impossible for
the element to jam in the cham~er. In operation the element is washed by
suction fluid. I'he heat produced during the compression stroke is trans-
ferred from the element directly to the suction fluid.
The suction stroke of the suction-valve element, and thus the
opening and closing times thereof, may be determined by a stop associated
with the element.
The suction-valve element may be fitted to the plunger in a manner
such that a high-pressure seal forms within the suction valve as an hydro-
static seal. During the suction stroke, the suction valve is opened by the
returning plunger as a result of the fluid friction arising in the seal.
During the compression stroke, fluid in the suction chamber is
drawn into the gap between the plunger and the suction-valve element and
supports the sealing action.
While the unit is in operation, the retention of the pump head
to the housing may be adjusted according to the hydraulic pressure present
in the pump head.
The object of the application may be used not only as a plunger
pump, but also as an homogenizing unit for cream, pastes, and the like, or
for the purpose of accelerating polymerization processes.
Various exemplary embodiments of the invention are described here-
inafter and are illustrated in the drawings attached hereto, wherein:
Figure 1 is a longitudinal section through th~ pressure and
suction chambers of a pump;
Figure 2 is a view in the direction of arrow II in Figure l;
Figure 3 is a detail of Figure 1 in cross section;
Figure 4 shows another embodiment in longitudianl section;
Figure 5 is a variant of the design in Figure 4;
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Figure 6 is a view in the ~irection of arrow VI in Figure 5;
Figure 7 shows an example of the U-shaped retainer shown in
Figure 1 for the pump head;
Figure 8 is a section through an additional anchorage between the
pump-head and pump-housing;
Figure 9 shows another embodiment of the pump in which the suction-
valve element is in two parts;
Figur0 10 is a variant of the design in Figure 9;
Figure 11 shows another embodiment of a high-pressure plunger pump
in longitudinal section;
Figure 12 shows a detail, in section, of the design according to
Figure 11, to an enlarged scale.
In the pump shown in Figure 1, pump housing 26 has a suction chamber
61 to which suction fluid flows through a passage 60. A plunger 46 enters
this suction chamber through a low-pressure seal 4, the plunger being
driven, for example, by means of a crankshaft, a connecting rod, and a
crosshead.
The drawing shows the plunger at forward dead centre, i.e. at the
end of the compression stroke.
It may be gathered from the illustration that the pump has very
little dead space at the forward dead-centre position.
The pump head 27 is secured to the pump housing 26 by means of a
U-shaped retainer 28. To this end, the legs of the U-shaped retainer are
provided with anchoring rims 29 engaging behind anchoring projections 30
on housing 26.
Figure 1 shows a dove-tail type of joint between housing 26 and
retainer 28. The latter may be pushed onto the housing from the side, to-
gether with pump head 27.
Pump head 27 is aligned with retainer 28 by means of centering
pins 31.
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In the embodiment according to Figures 1 and 2, after the pump
head and the retainer have been slid onto pump housing 26, toggle-bar screws
32 are tightened, threaded shanks 33 thereof passing through threaded holes
in the central web 34 of the retainer and bearing against pump head 27. This
presses pump head 27 against end-face 35 of housing 26 and presses anchoring
rims 29 against anchoring projections 30. The seal between pump head 29 and
end-face 35 of the housing is achieved by means of a sealing ring 35a.
Thus toggle-bar screws 32, 33 produce a prestress between the pump
head, the retainer, and the pump housing, and this is present at all times.
As a variant of the design illustrated in Figures 1 and 2, it is
also possible to replace toggle-bar screws 32, 33 with eccentrics 3-7
(Figures 5 and 6) mounted to pivot about axes 39 in recesses 38 in central
web 34 of retainer 28, the said eccentrics being actuated by means of handles
40,
Anchoring rims 29 on retainer 28 may extend over the whole width
of the retainer. It is, however, also conceivable, as shown in Figure 7,
to make the rims in sections, thus producing a plurality of hooks in spaced
relationship to each other.
It is also unnecessary for a dove-tail type of attachment to be
2Q provided between the anchoring rims and the anchoring projections. Instead,
the anchorage may be designed as shown in Figure 8. In this case, the coop-
erating surfaces of anchoring rims 22a and anchoring projections 30a are at
right angles to the wall of the pump housing.
~ alve seat 41 of pressure valve 42, and valve seat 43 of suction-
valve element 44, lie in the area of the parting plane between pump housing
26 and pump head 27. Should the valve seats require refinishing, this may
be carried out quite easily after removal of the pump head.
During the suction stroke of plunger 46, under the action of a
spring 47 pressure valve element 45 closes the pressure-valve aperture, thus
defining one end of collector chamber 48 provided in pump head 27 for the
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medium being delivered. At the end facing the valve aperture, collector
chamber 48 has an aperture which is closed off by a piston 49 arranged to
slide in the collector chamber and acting upon central web 34 of retainer 28.
The pressure in the collector chamber defines the pressure applied by piston
49 to the central web 34 of retainer 28.
Thus, when the pump is in operation, a clamping force dependent
upon the pressure in collector chamber 48 is superimposed upon the pre-load
produced by toggle-bar screws 32, 33 or eccentrics 37, 40.
Pressure-valve element 42 has a pin 50, the free end of which is
adapted to-slide in a blind bore 51. An angled passage 52 is provided in the
pin for the purpose of equalizing the pressure between the piston chamber
formed by the blind bore and the free end of the pin, and collector chamber
48.
Return spring 47 surrounding pin 50 rests with one end on piston
49.
The embodiments illustrated in the drawings have three plungers 46
and therefore three collector chambers 48 in pump head 27. These collector
chambers are connected together through a bore 53, through which pressure
equalization is effected within the pump head.
A sleeve-like suction~valve element 44 is slidably mounted on the
plunger 46 and consists of two cylindrical sleeves 54, 55 which are joined
together by shrinkage or auto frettage. Rear edge 56 of sleeve 54 forms a
supporting surface for the end of return spring 57 of suction-valve element
44. During the suction stroke of plunger 46, the suction-valve element
follows the movement of the plunger against the action of spring 57, rear
edge 58 of sleeve 55 comes up against a stop surface 59. This stop 59 limits
the stroke of suction-valve element 44, which is less than the maximal travel
of spring 57. During the suction stroke of the pump, the medium being
delivered is drawn through a housing aperture 60 into suction chamber 61 of
the pump, whence it passes to the space defined by suction-valve element 44
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and plunger 46, which forms the pressure chamber during the compressîon stroke
of the pump.
Thus in the object of the application, it is only suction-valve
element 44 that is subjected to alternating loads during the suction and com-
pression strokes.
The cross-sectional area of the pressure chamber, of diameter dl,
is larger than the cross-sectional area of the suction-valve seat, of dia-
meter d2, so that an additional closing force is produced for the suction
valve, during the compression stroke, by the pressure of water on the
differential area.
During the suction stroke, a negative pressure occurs in the inter-
nal chamber of the suction-valve element 44. This negative pressure, in
conjunction with the slight initial pressure in the pump suction chamber,
allows a force to act upon the valve element, which force assists the valve
as it moves in the opening direction.
It is also possible to provide plunger 46, and the inner surface
of the suction-valve element associated therewith, with a micro-labyrinth
seal in which the labyrinth recess in the plunger are in staggered relation-
ship to the divisions in the suction-valve element. Relative movement between
the plunger and the suction-valve element produces vortexing of the delivery
medium, and this intensifies the sealing action between the plunger and the
suction-valve element.
In the embodiment according to Figure 4, inside diameter d3 of
low-pressure seal 4, and the corresponding diameter of the plunger end which
does not enter the suction-valve element are larger than diameter dl of the
other part of the plunger.
This plunger configuration i s an advantage in the case of a high-
pressure plunger pump equipped with a plurality of plungers operating in a
chronologically staggered relationship to each other. During the compression
stroke of one plunger, end-face 22 of the plunger, produced by enlarged
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diameter d3, delivers suction fluid from suction chamber 2, through a pass-
age into the suction chambers of the other plungers. This improves the over-
all suction ratio.
Slidably mounted on the plunger 5 is a sleeve-like suction-valve
element 6, with which a biasing spring 7 is associated. One end of spring 7
rests against rear end 8 of the suction-valve element, while the other end
rests against a flange 9 on a sleeve 10 secured in the pump housing 1.
Sleeve 10 extends into the interior of cylindrical helical spring 7 with the
front end-face 11 of the sleeve limiting the return stroke of the suction-
valve element 6.
The sleeve-like design of the suction-valve element makes it easy,
from the production point of view, to produce a dimensionally stable suction-
valve element which does not change shape under the loads associated with the
compression stroke. Thus the sealing gap between the suction-valve element
and the plunger retains its predetermined size.
In the embodiment according to Figures 9 and lO, suction-valve
elements 85, 85a and 85b are made in two parts. In the design according to
Figure 9, the suction-valve element has a sleeve 87 guided on plunger 86 and
a valve part 88. A spring 90 is provided between valve part 88 and sleeve
87.
Sleeve 87 is arranged between pump head 9O and rear plunger guide
91 with a certain amount of play. Sleeve 87 has slots 92 adjacent pump head
90. In this embodiment, the suction-valve element is surrounded by an annu-
lar screen 93.
During the return stroke of the plunger, a vacuum is formed within
the suction-valve element, and this opens valve part 88 by compressing spring
89. If there is any initial pressure in suction chamber 94, this increases
the force acting to open valve part 88.
In the design according to Figure lO, valve part 88b is carried on
sleeve 87b. Spring 89b, arranged between sleeve 87b and valve part 88b, has
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one end bearing against a stop ring 95 secured to sleeve 87b. The other end
of spring 89b bears against rear end-face 96 of valve part 88b.
The designs according to Figures 9 and 10 are suitable for both
horizontal and vertical pumps.
In the embodiment according to Figures 11 and 12, pump housing
101, in which a plurality of plungers 102 may be arranged side by side, is
connected to pump head 104 by means of laterally insertable bars 103.
The pump housing has a suction chamber iO5 to which suction fluid
is delivered through a passage 106. Plunger 102 en~ers the suction chamber
through a seal 107, the plunger being driven by a crankshaft, a connecting
rod, and a crosshead.
Suction-valve element 108 is carried entirely on the plunger.
Associated with the suction-valve element is a spring 109 which endeavours
to keep the said element in the closed position shown in Figure 14, During
the suction stroke, the force of spring 109 must be overcome by suction-
valve element 108. The suction stroke is limited by a stop 1~ which co-
operates with rear end-face 111 of the suction-valve element.
Plunger 102 has a rod part 112 and a sleeve 113 enclosing the rod
part.
2n In the forward area of plunger 102, rod part 112 has a reduced
diameter forming an annular space 114 defined peripherally by sleeve 113.
This annular space is connected through a transverse passage 115, and a pass-
age 116 lying on the longitudinal axis of the plunger, with pump pressure
chamber 117, formed by suction-valve element 108. In this embodiment,
passage 116 passes through a threaded stud, extending from the front face of
rod part 112, onto which a nut 118 is screwed in order to secure a stop
plate 119 for the front annular surface of sleeve 113. Seat 120 of the suc-
tion valve, and seat 121 of pressure valve element 122, are arranged on a
valve-seat ring 123. This valve-seat ring, which is mounted in a recess in
pump head 104, can easily be replaced after the pump head has been removed
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from the pump housing.
A sealing ring 124 is provided, adjacent the rear end of the
annular space, 114 between rod part 112 and sleeve 113 of the plunger.
Figure 12 shows the sealing gap 125 between suction-valve element
108 and sleeve 113 of plunger 102, to an enlarged scale.
The pressure in pressure chamber Pl decreases, in sealing,gap 125,
in the direction of the drive-end of the plunger, reaching a valve P2 in the
end
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area of annular space 114.
Since annular space 114 is slightly staggered towards the drive-end,
in relatlon to the front end of the plunger, the pressure in the sealing gap
associated with annular space 114 is lower, during the compression stroke,
than the pressure in annular space 114, which coincides with the pressure in
pressure chamber 117. This deforms sleeve 113, as shown in dotted lines in
Figure 15, leading to a reduction in the cross section of sealing gap 125.
The deformation of the plunger sleeve, induced by the pressure of
the medium being delivered, lies within the elastic limit of the sleeve, so
that when the pressure drops, the sleeve again assumes its normal shape. This
ensures a satisfactory seal between the plunger and the suction-valve element
in the case of plunger pumps operating at very high pressures, of 1000 bars and
more, for example.
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