U.S. patent application number 11/400910 was filed with the patent office on 2006-11-09 for metering pump for varnish or lacquer.
This patent application is currently assigned to J.S. Staedtler GmbH & Co.. Invention is credited to Udo Klein, Joachim Kunkel, Winfried Ott.
Application Number | 20060251528 11/400910 |
Document ID | / |
Family ID | 37054992 |
Filed Date | 2006-11-09 |
United States Patent
Application |
20060251528 |
Kind Code |
A1 |
Klein; Udo ; et al. |
November 9, 2006 |
Metering pump for varnish or lacquer
Abstract
A metering pump for varnish or laquer includes a housing in
which are arranged a first gear wheel and a second gear wheel which
is in engagement with the first gear wheel. At least the first gear
wheel is mounted with a shaft in the housing. The pump further has
a sealing device provided for the first gear wheel, wherein each
gear wheel has a conveying area formed by a toothing, and wherein
the sealing device is arranged between the conveying area and an
end face area of the gear wheel. The sealing device is sealed in
the housing by a radial sealing device.
Inventors: |
Klein; Udo; (Dietzenbach,
DE) ; Kunkel; Joachim; (Rothenbuch, DE) ; Ott;
Winfried; (Rodgau, DE) |
Correspondence
Address: |
Friedrich Kueffner
Suite 910
317 Madison Avenue
New York
NY
10017
US
|
Assignee: |
J.S. Staedtler GmbH &
Co.
|
Family ID: |
37054992 |
Appl. No.: |
11/400910 |
Filed: |
April 8, 2006 |
Current U.S.
Class: |
417/366 |
Current CPC
Class: |
F04C 13/00 20130101;
B05B 9/0416 20130101; F04C 15/0026 20130101 |
Class at
Publication: |
417/366 |
International
Class: |
F04B 39/06 20060101
F04B039/06 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 12, 2005 |
DE |
10 2005 016 670.9 |
Claims
1. A metering pump for varnish or lacquer, the pump comprising a
housing, a first gear wheel, and a second gear wheel in engagement
with the first gear wheel, wherein at least the first gear wheel is
mounted with a shaft in the housing, further comprising a sealing
device for the first gear wheel, wherein each gear wheel has a
conveying area formed by a toothing, and wherein the sealing device
is arranged between the conveying area and an end face area of the
gear wheel, further comprising a radial sealing device for sealing
the sealing device in the housing.
2. The metering pump according to claim 1, wherein the toothing has
a base circle and wherein a radial distance between the sealing
device and the base circle is smaller than a radial distance
between the sealing device and the shaft.
3. The metering pump according to claim 2, wherein the radial
distance between the base circle and the sealing device is
.ltoreq.1 mm.
4. The metering pump according to claim 1, wherein the sealing
device is mounted in the housing so as to be nonrotatable.
5. The metering pump according to claim 1, wherein each gear wheel
has at least in an area of the sealing device a wear-resistant
surface.
6. The metering pump according to claim 5, wherein the
wear-resistant surface is comprised of a DLC-coating.
7. The metering pump according to claim 1, wherein the sealing
device is a sliding ring seal.
8. The metering pump according to claim 7, wherein the sliding ring
seal is comprised at least at a sealing surface thereof of a metal,
a hard metal, a ceramic materia, or a fluoroplastic material.
9. The metering pump according to claim 1, wherein the radial
sealing device is mounted in the housing with little dead
space.
10. The metering pump according to claim 1, wherein a mounting gap
exists between the radial sealing device and the conveying area,
wherein a rinsing medium which flows through the conveying area
flows through the mounting gap.
11. The metering pump according to claim 1, wherein the sealing
device seals axially at the gear wheel and radially in the housing
in a direction of the conveying area.
12. The metering pump according to claim 11, comprising a
tensioning device for axially and radially pretensioning the
sealing device.
13. The metering pump according to claim 1, further comprising a
supply connection of a protective medium ending radially within the
sealing device.
14. The metering pump according to claim 1, wherein both gear
wheels are mounted in the housing on a shaft each.
15. The metering pump according to claim 14, wherein the gear
wheels are mounted axially on both sides in the housing.
16. The metering pump according to claim 1, wherein the housing
comprises an assembly surface, wherein a lacquer supply connection
and a lacquer discharge connection end in the assembly surface,
wherein a drive train for the first gear wheel extends through the
assembly surface and wherein a supply block is mounted on the
assembly surface.
17. The metering pump according to claim 16, wherein the shaft of
the first gear wheel ends in an area of the assembly surface and
has a coupling profile at the assembly surface.
18. The metering pump according to claim 16, wherein the supply
block has a projection surrounding the drive train, wherein the
projection engages in a recess of the assembly surface.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a metering pump for varnish
or laquer. The pump includes a housing in which are arranged a
first gear wheel and a second gear wheel which is in engagement
with the first gear wheel. At least the first gear wheel is mounted
with a shaft in the housing. The pump further has a sealing device
provided for the first gear wheel, wherein each gear wheel has a
conveying area formed by a toothing, and wherein the sealing device
is arranged between the conveying area and an end face area of the
gear wheel.
[0003] 2. Description of the Related Art
[0004] A gear pump having the features described above is known
from DE 19 56 528 A. In order to seal the area of the pump which
does not come into contact with the material to be conveyed, for
example, the shaft, relative to the conveying area, an elastic or
resilient sealing device is arranged at the end faces of the gear
wheels directly underneath the toothing. For accommodating the
sealing device, recesses are provided either in the housing walls
or in the end faces of the gear wheels.
[0005] Metering pumps for varnish or lacquer have been found useful
in the lacquering technology. They are important means for
achieving a varnish application which is of a high quality and
uniform.
[0006] When carrying out many lacquering tasks, for example,
lacquering of motor vehicle bodies, a color change is relatively
frequently required. It is essential in this connection that the
color metered by the metering pump is not contaminated by the
previously used color. For example, if a white lacquer is applied
to a vehicle body, even the smallest residues of the lacquer are
extremely detrimental to a previously applied red color.
[0007] Consequently, the metering pump is cleaned between the
application of two colors. For this purpose, a rinsing liquid is
conducted through the pump in the same manner essentially as the
previously conducted lacquer or color liquid. The pump is operated,
so that the rinsing liquid can flush out the color residues which
are still in the pump. However, this procedure requires a
relatively long time and also a relatively large quantity of
rinsing liquid.
[0008] The prior art discloses measures for minimizing the area
which comes into contact with the lacquer or colored liquids in
order to be able to effectively rinse out the color residues.
[0009] WO 01/86150 A1 discloses a metering pump in which the first
gear wheel is unilaterally connected to a shaft in the housing. The
second gear wheel is freely arranged in the housing and is guided
by a wall which surrounds the second gear wheel. The shaft of the
first gear wheel is guided by a sleeve which is radially sealed
relative to the housing by means of an O-ring.
[0010] DE 198 49 200 A1 discloses a gear pump with sealing devices,
wherein the sealing devices are arranged between the end face of
the gear wheels and the housing wall. Chambers which can be
pressurized are arranged underneath the sealing devices. This
pressure then acts from the other side of the sealing device
against the pressure of the liquid to be conveyed and thereby, in
addition to the sealing devices, prevents the penetration of the
liquid into protected areas.
[0011] WO 98/25029 A1 discloses a motor pump unit in which the pump
is constructed as a gear pump. in order to protect the drive shaft
of the gear wheel from the conveyed liquid, an annular groove is
provided at the end face of the gear wheel, wherein the annular
groove receives a sealing means which seals the end face of the
gear wheel relative to the housing wall. The sealing means is
composed of an O-ring and an additional ring which is stationary
relative to the O-ring and protects the O-ring against wear due to
friction.
[0012] EP 1 164 293 A2 describes a rinsable gear pump. Additional
ducts ensure that the rinsing agent flows through the bearing gap
of the drive shaft over the entire width of the bearing. This
ensures an effective cleaning of the gear pump, so that no sealing
device is required between the end faces of the gear wheels and the
housing wall.
[0013] DE 26 06 172 C2 discloses a rotary piston machine for
liquids. The machine has an externally meshing gear wheel which is
in engagement with an internally meshing gear wheel which has one
tooth more than the externally meshing gear wheel. The sealing
device between the externally meshing gear wheel and the housing
wall is accommodated in an annular groove and consists of an
elastic sealing ring and a metal sealing ring. The metal sealing
ring remains stationary relative to the elastic sealing ring,
however, the metal sealing ring produces a slight friction with
respect to the side wall.
SUMMARY OF THE INVENTION
[0014] Therefore, it is the primary object of the present invention
to provide a metering pump which operates economically.
[0015] In accordance with the present invention, in a metering pump
of the above-described type, the above object is met by sealing the
sealing device in the housing by means of a radial sealing
device.
[0016] As a result of the configuration according to the present
invention, it is ensured that no varnish or lacquer liquid can flow
past the sealing device so that a contamination of the components
which should be kept clean will not occur. This radial sealing
device may be constructed simply as an O-ring, because it must only
seal between two static components, i.e., the housing and the
sliding ring seal. The areas into which the lacquer liquid can
penetrate remain small because they are defined by the sealing
device. The farther out the sealing device is arranged, the greater
is an end face area at the end face of the gear wheel to which the
lacquer liquid can no longer be admitted. Consequently, the sealing
device automatically also holds back lacquer liquid from the shaft,
so that sealing the shaft relative to the outside is essentially
less complicated. Of course, there still remain in the area of the
toothing surfaces of the gear wheel on the side of the end face,
namely, the end faces of the individual teeth. Lacquer liquid can
penetrate into these areas. However, this is not critical because
rinsing liquid can also penetrate into these areas in a manner
which is comparable to the penetration of the lacquer liquid.
Consequently, it is relatively simple to ensure that the rinsing
liquid has sufficiently removed the previous color since the area
to be rinsed is smaller, less rinsing agent is required. This saves
cost. The rinsing time is shortened. This also increases the useful
life of the pump. The pump also usually has a longer service life
because it is reliably ensured that the lacquer liquid does not
penetrate into the bearing areas by means of which the shaft is
supported in the housing. All of these factors make the operation
of the pump constructed in this manner extremely economical.
[0017] Preferably, the toothing has a base circle, and a radial
distance between the sealing device and the base circle is smaller
than a radial distance between the sealing device and the shaft.
Independently of the diameter of the gear wheels being used, it is
ensured that the lacquer liquid which can be admitted into the area
between the gear wheel and the housing can be kept small.
[0018] The radial distance between the base circle and the sealing
device is preferably .ltoreq.1 mm. The sealing device should not be
arranged directly at the base circle, so that the risk of damage
due to passing tooth gaps is kept small. However, if a spacing is
provided which is 1 mm or less, it is ensured, on the one hand,
that the risk of damage to the sealing device is small. On the
other hand, it is ensured that the area which can be contaminated
does not become too large.
[0019] The sealing device is arranged preferably in the housing so
as to be nonrotatable relative to the housing. Accordingly, the
sealing device remains stationary. The sealing device is not taken
along by the rotating gear wheel. This keeps the wear down.
[0020] The gear wheel preferably has at least in the area of the
sealing device a wear-resistant surface. This wear-resistant
surface can be deposited on the gear wheel. This wear-resistant
surface can also be formed by an insert which interacts with the
sealing device. A wear-resistant surface increases the service
life.
[0021] In accordance with a particularly preferred feature, the
wear-resistant surface has a DLC-coating. "DLC" means "diamond-like
carbon," i.e., a carbon coating similar to diamonds. The material
especially has excellent sliding properties. The coating is
particularly suitable for interacting with low friction with the
sealing device. It is also possible to provide the entire gear
wheel with a DLC-coating.
[0022] Preferably, the sealing device is a sliding ring seal. Such
seals can be manufactured of materials which are wear and corrosion
resistant and have good frictional properties.
[0023] It is particularly preferred in this connection that the
sliding ring seal has at least at its sealing surface a metal,
particularly a hard metal, a ceramic material or a fluorocarbon
material. Such materials have a sufficient wear resistance and
additionally ensure a sufficient sealing effect. Preferably,
silicon carbide SiC is used.
[0024] The radial sealing device is preferably arranged with little
dead space in the housing. In other words, the radial sealing
device is arranged in such a way that only a small space remains
between the conveying area and the radial sealing device which
could be contaminated by lacquer liquid. In the same manner,
cleaning of this small dead space is equally simple.
[0025] It is equally advantageous if a mounting gap remains between
the radial sealing device and the conveying area, wherein a rinsing
agent which flows through the conveying area can flow through the
mounting gap. In the same manner in which lacquer liquid can
penetrate to the radial sealing device, it is ensured that the
rinsing liquid, which must be introduced anyway for cleaning the
conveying area and the remaining areas of the metering pump, can
penetrate up to the radial sealing device in order to rinse out the
lacquer liquid.
[0026] The sealing device preferably provides a sealing effect
axially at the gear wheel and radially in the housing toward the
conveying area. The most important aspect is the axial sealing
effect relative to the gear wheel. This ensures that the end face
of the gear wheel can for the most part be kept free of lacquer
liquid. The radial sealing device merely prevents a circumvention
of the axial sealing device.
[0027] It is also advantageous if the sealing device is axially and
radially pretensioned by means of a tensioning device. The
tensioning device makes it possible to adjust the sealing forces,
so that the penetration of lacquer liquid in areas in which the
lacquer liquid is not desired, can be reliably avoided.
[0028] A supply connection of a protective medium preferably ends
radially within the sealing device. Such a protective medium may be
a liquid, for example, a protective oil. The protective medium can
be used for building up a pressure within the sealing device,
wherein the pressure corresponds to the pressure of the lacquer
liquid outside of the sealing device. This reliably prevents
lacquer liquid from penetrating past the sealing device.
[0029] Preferably, both gear wheels are mounted with a shaft each
in the housing. This keeps the wear of the second gear wheel low.
This does result in an additional area, i.e., the bearing area of
the shaft of the second gear wheel, which theoretically could be
contaminated. However, if a corresponding seal is also provided at
the gear wheel, this risk again is eliminated.
[0030] The gear wheels are preferably supported axially on both
sides in the housing. In other words, a shaft extends through each
gear wheel or the gear wheels have shaft stubs on both sides. This
has the advantage that practically no bending forces act on the
bearing of the gear wheels. The shafts on both sides can also be
reliably sealed by means of the sealing device described above.
[0031] The housing preferably has an assembly surface where a
lacquer supply connection and a lacquer discharge connection are
located, wherein a drive train for the first gear wheel extends
through the assembly surface, wherein a supply block is mounted at
the assembly surface. Even when the metering pumps operate
reliably, it is occasionally necessary to carry out maintenance or
an exchange. If the connections are provided practically only in
the assembly surface, the connections at supply and discharge and
the connection in the drive train are simultaneously disconnected
when the housing is separated from the supply block. Additional
measures for providing lines or other connections are practically
not required. Accordingly, the metering pump is divided into two
modules, i.e., the supply block on the one hand, and the housing
with the two gear wheels, which form the actual pump, on the other
hand. This significantly facilitates maintenance.
[0032] The shaft of the first gear wheel preferably ends in the
area of the assembly surface and is provided there with a coupling
profile. When the housing is to be exchanged, then the shaft does
practically not project beyond the assembly surface or projects
only to a slight extent. This means that the housing remains very
compact which, in turn, facilitates transport and reduces the
danger of injury.
[0033] Preferably, the supply block has a projection which
surrounds the drive train, wherein the projection engages in a
recess of the assembly surface. This projection facilitates the
assembly of the housing at the supply block. Moreover, the area of
the connection between the supply block and the housing which is
subjected to the greatest mechanical load, is constructed in such a
way that this load can be absorbed without problems.
[0034] The various features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
to and forming a part of the disclosure. For a better understanding
of the invention, its operating advantages, specific objects
attained by its use, reference should be had to the drawing and
descriptive matter in which there are illustrated and described
preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
[0035] In the drawing:
[0036] FIG. 1 is a longitudinal sectional view of a metering pump
for varnish or lacquer, shown in a partially disassembled
state;
[0037] FIG. 2 is a sectional view taken along sectional line II-II
of FIG. 1; and
[0038] FIG. 3 is a detail of FIG. 1 on a larger scale.
DETAILED DESCRIPTION OF THE INVENTION
[0039] FIG. 1 of the drawing shows a metering pump 1 for varnish or
lacquer in a cross-sectional view and divided into two structural
groups.
[0040] The metering pump 1 has a housing 2 which is formed by an
upper plate 3, a lower plate 4, and an intermediate plate 5. As can
be seen in FIG. 2, the intermediate plate 5 has two approximately
circular recesses 6, 7 which partially overlap. A first gear wheel
8 is arranged in the first recess 6 and an second gear wheel 9
which meshes with the first gear wheel 8 is arranged in the second
recess 7.
[0041] A gear pump of this type operates as follows. The first gear
wheel 8 is driven by a shaft 10 in a direction 11 and drives the
second gear wheel 9 which rotates in a direction 12 having an
opposite direction of rotation. The teeth of the two gear wheels 8,
9 engage in each other in an engagement area 13. When leaving the
engagement area 13, a volume existing between the teeth is
enlarged, so that a lacquer liquid can flow from a supply
connection 14 into the intermediate spaces between the teeth. A
lacquer liquid present in the intermediate spaces between the teeth
is then taken along by the teeth of the two gear wheels 6, 7 in the
direction of movement. The intermediate spaces between the teeth
are closed after a short duration of rotation by the intermediate
plate 5. The liquid present in the intermediate spaces between the
teeth is then displaced in the engagement area from the
intermediate spaces and can be discharged through the discharge
connection 15. The operation of such a gear pump is known in the
art.
[0042] Instead of a gear pump having two gear wheels with external
gear engagement, it is also possible in a corresponding manner to
use a gear pump having an externally engaging gear wheel and an
internally engaging gear wheel, wherein the externally engaging
gear wheel has a smaller diameter than the internally engaging gear
wheel and both gear wheel are arranged eccentrically relative to
each other. In that case, a sickle-shaped disc is arranged in a gap
area between the two gear wheels. This type of sickle pump is also
known in the art and can be used in a similar manner in the present
case.
[0043] Each gear wheel 8, 9 has teeth with tooth tips and
intermediate spaces between the teeth, and tooth bases. The tooth
tips are situated in each gear wheel 8, 9 on a tip circle 16. The
tooth bases are located in each gear wheel on a base circle 17. A
conveying area 18, 19 seen in FIG. 1 is defined between the tip
circle 16 and the base circle 17.
[0044] As can be seen in FIG. 1, the two gear wheels 8, 9 and the
intermediate plate 5 have practically the same thickness.
Accordingly, the two gear wheels 8, 9 rest against the plate 3 and
the lower plate 4; of course, a small play exists in order to
facilitate the rotary movement of the two gear wheels 8, 9 in the
housing 2.
[0045] In order to prevent the lacquer liquid from penetrating into
the area between the two gear wheels 8, 9 and the upper plate 3 or
the lower plate 4, each gear wheel 8, 9 has a sealing device 20-23
at its upper side as well as at its lower side. All sealing devices
20-23 are principally of the same construction. These seals 20-23
will therefore be explained in connection with the sealing device
21 seen in FIG. 1 or the sealing device 20 seen in FIG. 3.
[0046] The sealing device 21 has an axial projection 24 which does
not extend over the entire circumference of the sealing device 21.
This projection 24 engages in a corresponding recess in the lower
plate 4 and, thus, ensures that the sealing device 21 does not
rotate.
[0047] A spring element 25 biases the sealing device 21 with a
small force in the direction of the gear wheel 8. Consequently, an
O-ring 26 surrounds the sealing device 21 and ensures that lacquer
liquid does not flow from the conveying area 18 past the side of
the sealing device 21 facing away from the gear wheel 8.
[0048] The sealing device 21 interacts with an insert 27 which is
arranged in the end face of the gear wheel 8. This insert 27 has an
increased resistance to wear. It may be made, for example, of
ceramic or a metal, particularly a hard metal. It is also possible
to provide this insert 27 with a DLC-coating, i.e., a diamond-like
coating. A DLC-coating may also be applied directly on the end face
of the gear wheel 8.
[0049] As can be seen in FIG. 3, the radial sealing device 26 which
seals the sealing device 20 relative to the housing 2 is mounted
with little dead space in the housing 2. The dead space is
practically only determined by the fact that the web which holds
the radial sealing device 26 may not be too thin, so that it will
not break. Remaining between the conveying area 18 and the radial
sealing device 26 is a mounting gap 47 which is dimensioned in such
a way that a rinsing liquid which flows through the conveying area
18 can also flow through the mounting gap 47, so that any lacquer
liquid which has penetrated up to this point can be conveyed away
by the rinsing liquid.
[0050] As can be seen in FIG. 3, the tensioning means 25 is
constructed as a set of springs. The tensioning means tensions the
sealing device 20 axially relative to the end face of the gear
wheel 8. Simultaneously, the tensioning means 25 can be constructed
in such a way that it radially outwardly tensions the sealing
device relative to the housing 2. This can be realized in a simple
manner by providing the set of springs 25 with an external diameter
which is slightly greater than the internal diameter of the sealing
device 20.
[0051] The sealing device 21 is constructed as a sliding ring seal.
The sealing device 21 may also be of a material which is resistant
to wear, particularly metal, for example, hard metal, a ceramic
material or a fluoroplastic material, preferably silicon
carbide.
[0052] As mentioned above, the first gear wheel 8 is mounted with a
shaft 10 in the housing 2. The second gear wheel 9 is also mounted
with a shaft 28 in the housing. The two shafts 10, 28 are
rotatable, wherein the shaft 10 is connected through a wedge 29 so
as to rotate with the first gear wheel 8.
[0053] As can be seen in FIG. 1, the radial distance of the sealing
devices 20-23 from the conveying area 18, 19 is significantly
smaller than the radial distance between the sealing devices 20-23
and the shafts 10, 28. More precisely, the distance refers to the
side of the sealing devices 20-23 which faces the lacquer liquid,
i.e., the point up to which the lacquer liquid can penetrate.
Accordingly, it is clearly visible that the areas at the end faces
of the gear wheels 8, 9, which could be contaminated by the lacquer
liquid, are relatively small. Similarly, only a small quantity of
rinsing liquid is required if the metering pump 1 must be cleaned
between two colors.
[0054] The radial distance between the sealing devices 20-23 and
the conveying areas 18, 19 should in all cases be at most 1 mm. On
the one hand, this maintains the area at the end faces of the gear
wheels 8, 9 which can be contaminated by lacquer liquid. On the
other hand, there is little danger that the sealing devices 20-23
will be located alternatingly opposite a tooth and a tooth gap and
will wear.
[0055] For cleaning the metering pump, a cleaning liquid or rinsing
liquid is supplied in a similar manner as the lacquer liquid
through the supply connection 14 and is discharged through the
discharge connection 15. This rinsing liquid penetrates into the
same areas as previously the lacquer liquid and takes with it the
color residues in these areas.
[0056] In addition, a sealing oil supply 30 is provided which ends
radially within the sealing devices 20-23. For this purpose, a
sealing oil supply has a main duct 31 from which extend two branch
ducts 32, 33 which, in turn, have branches 34 to 37 which extend
radially in the shafts 10, 28 and end approximately in the areas of
the axial ends of the gear wheels 8, 9 in an area between the shaft
10 or 28 and the gear wheel 8 or 9.
[0057] The shaft 10 additionally has a shaft sealing device 38
whose primary purpose is to prevent the sealing oil from emerging
from the housing 2. Lacquer liquid is already prevented by the
sealing devices 20-23 to a sufficient extent from being able to
escape from the housing 2.
[0058] The housing 2 has an assembly surface 39 in which the supply
connection 14 ends. The supply connection 14, as seen in FIG. 2, is
not arranged in the same plane as the axes of the shafts 10, 28.
The discharge connection 15 also ends in the assembly surface,
however, it is perpendicularly offset relative to the drawing plane
of FIG. 1. The shaft 10 ends approximately in the assembly line 39.
It has a coupling profile 40 at this end.
[0059] The purpose of the assembly surface 39 is to be able to
mount a supply block 41 on the housing 2. The supply block 41 is
fastened to the housing 2 by means which are not illustrated in
detail, such as bolts. Lines 42 to the supply connection 14 or the
discharge connection 15 are arranged in the supply block 41,
wherein the lines can be closed or opened by a valve 43. Moreover,
a drive shaft 44 is arranged in the supply block 41, wherein the
drive shaft 44 is connected to a drive motor which is not
illustrated in detail. When the supply block 41 is mounted on the
housing 2, the drive shaft 44 is in engagement with the shaft 10,
so that the gear well 8 can be driven.
[0060] The supply block 41 has a projection 45 which surrounds the
drive shaft 44, wherein the projection 45 protrudes into a
corresponding recess 46 in the upper plate 3 when the supply block
41 is mounted on the housing 2. On the one hand, this makes it
possible to achieve an alignment of the drive shaft 44 relative to
the shaft 10. On the other hand, the mechanical strength of the
connection between the housing 2 and the supply block 41 is
increased.
[0061] Accordingly, if the metering pump 1 is to be disassembled by
removing the housing 2 from the supply block 41 it is only
necessary to separate the mechanical connection between the supply
block 41 and the housing 2 and it is then possible to pull the
housing 2 from the supply block 41, which usually is mounted so as
to be stationary, perpendicularly relative to the assembly surface
39. This separates the mechanical drive connection to the drive
shaft 44 as well as the liquid connection to the ducts 42.
[0062] Of course, it is also possible that the sealing oil supply
30 extends through the supply block 41, however, this feature is
not illustrated.
[0063] While specific embodiments of the invention have been shown
and described in detail to illustrate the inventive principles, it
will be understood that the invention may be embodied otherwise
without departing from such principles.
* * * * *