U.S. patent application number 16/307233 was filed with the patent office on 2019-08-22 for oil-lubricated rotary vane vacuum pump.
This patent application is currently assigned to Gebr. Becker GmbH. The applicant listed for this patent is Gebr. Becker GmbH. Invention is credited to Islam AKYILDIZ, Artjom KRAFT, Markus LOEBEL, Frank RISCHEWSKI.
Application Number | 20190257310 16/307233 |
Document ID | / |
Family ID | 59285229 |
Filed Date | 2019-08-22 |
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United States Patent
Application |
20190257310 |
Kind Code |
A1 |
KRAFT; Artjom ; et
al. |
August 22, 2019 |
OIL-LUBRICATED ROTARY VANE VACUUM PUMP
Abstract
An oil-lubricated rotary vane vacuum pump has a rotary vane unit
that includes a rotary vane chamber and a rotary vane rotor. The
vacuum pump has an oil separation and reprocessing device in which
oil and gas that have penetrated into the rotary vane unit are
separated by a separation device formed by a filter element and/or
a gravitational and/or impact separator and/or a fine particle
separator, preferably along with an oil foam decomposition device
and/or with an oil cooler and/or with an oil pump. One or more
monitoring and/or maintenance devices are provided for the devices,
and the oil separation and reprocessing device is accommodated in
an oil separation and reprocessing housing. The gas successively
flows through two separation devices within the oil separation and
reprocessing housing, and the two separation devices are both
accessible for maintenance from a face wall.
Inventors: |
KRAFT; Artjom; (Bochum,
DE) ; AKYILDIZ; Islam; (Dortmund, DE) ;
LOEBEL; Markus; (Bochum, DE) ; RISCHEWSKI; Frank;
(Hilden, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Gebr. Becker GmbH |
Wuppertal |
|
DE |
|
|
Assignee: |
Gebr. Becker GmbH
Wuppertal
DE
|
Family ID: |
59285229 |
Appl. No.: |
16/307233 |
Filed: |
July 5, 2017 |
PCT Filed: |
July 5, 2017 |
PCT NO: |
PCT/EP2017/066770 |
371 Date: |
December 5, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 2220/10 20130101;
F04C 2210/22 20130101; F04C 29/02 20130101; F04C 29/026 20130101;
F04C 25/02 20130101; F01C 21/007 20130101; F01C 21/10 20130101;
F04C 18/3446 20130101; F04C 2240/809 20130101 |
International
Class: |
F04C 29/02 20060101
F04C029/02; F04C 18/344 20060101 F04C018/344; F04C 25/02 20060101
F04C025/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 8, 2016 |
DE |
10 2016 112 570.9 |
Claims
1. An oil-lubricated rotary vane vacuum pump (1) with rotary vane
power unit (2), comprising a rotary vane chamber (5) and a rotary
vane rotor (6) and with an oil separating and recycling unit (3),
wherein a separation of oil and gas, which has passed through the
rotary vane power unit (2), is effected in the oil separating and
recycling unit (3) by a separating device (T.sub.1, T.sub.2), which
is preferably formed by a filter element and/or by a gravity and/or
impact separator (24) and/or a fine separator (25), preferably in
conjunction with an oil foam degradation unit and/or with an oil
cooler and/or with an oil pump, wherein one or more monitoring
and/or maintenance units (37) are provided for the said units and
the oil separating and recycling unit (3) is accommodated in an oil
separating and recycling housing (13) with sidewalls (14, 15), a
bottom wall (16), a ceiling wall (17) and face walls (18, 19),
wherein the sidewalls (14, 15) extend transversely to a rotation
plane of the rotary vane rotor (6) and define a longitudinal
extension of the oil separating and recycling housing (13), wherein
the gas within the oil separating and recycling housing (13) flows
through two separating devices (T.sub.1, T.sub.2), which are both
accessible for maintenance from a face wall (18).
2. The rotary vane vacuum pump according to claim 1, wherein both
separating devices (T.sub.1, T.sub.2) are singly insertable and
removable.
3. The rotary vane vacuum pump according to claim 1, wherein both
separating devices (T.sub.1, T.sub.2) are connected to each other,
combined for joint insertion and removal.
4. The rotary vane vacuum pump according to claim 1, wherein a gas
path is formed without valves between the separating device
(T.sub.1), which is first in gas flow direction (b) and the
separating device (T.sub.2), which is second in gas flow direction
(b).
5. The rotary vane vacuum pump according to claim 1, wherein the
length (c) of the gas path between the separating device (T.sub.1),
which is first in gas flow direction (b) and the separating device
(T.sub.2), which is second in gas flow direction (b) corresponds to
a diameter dimension or less, of the first separating device
(T.sub.1).
6. The rotary vane vacuum pump according to claim 1, wherein a
further separating device (T.sub.3) is provided, for example in the
form of a gravity and/or impact separator (24).
Description
FIELD OF THE ART
[0001] The invention relates to an oil-lubricated rotary vane
vacuum pump with rotary vane power unit comprising a rotary vane
chamber and a rotary vane rotor, and with an oil separating and
recycling unit, wherein the separation of oil and gas, which has
passed through the rotary vane power unit, is performed in a
separating unit, which is preferably formed by a filter element
and/or a gravity and/or impact separator and/or a fine separator,
preferably together with an oil foam degradation unit and/or with
an oil cooler, wherein one or more monitoring and/or maintenance
units are provided for the said units and the oil separating and
recycling unit is accommodated in an oil separating and recycling
housing, with sidewalls, a bottom wall, a ceiling wall and face
walls, wherein the sidewalls extend transversely to a rotation
plane of the rotary vane rotor and define a longitudinal extension
of the oil separating and recycling housing.
STATE OF THE ART
[0002] Oil-lubricated rotary vane vacuum pumps of the kind
discussed here are known. These normally consist of a rotary vane
blower with a rotary vane housing forming a rotary vane chamber,
which rotary vane chamber is configured as a cylindrical bore. The
rotary vane rotor is normally cylinder-shaped, with slides which
are arranged in slots of the rotor. The slots in the rotor may be
strictly radially aligned with regard to a cross-section through
the rotor or extending at an acute angle to a radial. Mounting of
the rotor according to the state of the art is preferably given in
the vicinity of the lateral covers terminating the rotary vane
housing at either end.
[0003] When the vacuum pump is in operation the rotor rotates
radially offset relative to the centre axis of the rotary vane
housing. This results in closed chambers separated by the
essentially radially movably arranged slides, the size of which
changes during a revolution of the rotor. From the changes in size
differences in pressure result between individual chambers and thus
between the inlet side and the outlet side of the pump.
[0004] With oil-lubricated rotary vane vacuum pumps oil is
introduced into the rotary vane housing. Due to the oil gaps
between the different components get blocked. This also obstructs
the gas exchange between the adjusting chambers between the slides.
In this way higher vacuums are achieved in operation than with
so-called dry-running rotary vane vacuum pumps.
[0005] Depending on the design the oil together with the conveyed
gas is conveyed from the last chamber into the outlet. In addition,
due to the compression enthalpy in the system, the oil in the
system is heated. Also, the oil as a result of coming into contact
with the conveying medium, can become contaminated or can change as
a result of possible chemical reactions. The consequence of this is
a preferred recycling of the oil after it has left the blower area.
In this respect it is known to arrange for the oil to circulate in
a cycle through the appliance.
[0006] Further it is known to essentially perform the recycling
process in three part processes. As such separation of the oil and
gas is initially performed in several stages, as required. Coarse
separation of large oil drops through a respective filter element
may be provided as well as alternatively or in combination
therewith, a gravity and/or impact separation by redirecting the
gas and oil mixture and alternatively or in combination therewith,
by slowing the flow. To separate the oil and gas a fine separation
may further be provided, wherein the gas current is for example
guided through a special filter mat. In a further part process
degradation of the oil foam may be provided. Air bubbles enclosed
in the oil can get into the rotary vane chamber in the form of foam
and disadvantageously affect the function of the pump.
[0007] One or more monitoring and/or maintenance units may be
provided, for example an electrical oil level sensor and/or oil
level sight glass and/or an oil temperature monitor.
[0008] Moreover it is known to house the oil separating and
recycling unit in an oil separating and recycling housing, which is
separate from the rotary vane housing, but coupled thereto as
required. The sidewalls of such a housing extend transversely to
the rotation direction of the rotary vane rotor and thus preferably
essentially in axial extension direction of the rotary vane
rotor.
SUMMARY OF THE INVENTION
[0009] With regard to the described state of the art, the invention
deals with the task of further improving a rotary vane vacuum pump
of the type discussed and implemented so as to be favourable to
handling and/or maintenance and/or manufacturing, in particular as
regards oil separation.
[0010] One possible solution to the requirement according to a
first inventive idea presents itself for an oil-lubricated rotary
vane vacuum pump, where the aim is for the gas within the oil
separating and recycling housing to flow in succession through two
separating devices, both of which are accessible for maintenance
from one face wall.
[0011] According to the invention (at least) two separating devices
for the separation of oil and gas are provided in gas flow
direction. This results in an altogether better oil separation. The
first separating device when viewed in flow direction may be a fine
separating device, the second separating device in flow direction
may be a post-separating device for separating fine to finest oil
particles from the gas current.
[0012] Both separating devices are arranged within the oil
separating and recycling housing. Any interfaces on the housing for
connecting an external, additionally assignable separating device
are not necessary. Such interfaces as well as lines leading out of
them, for example hoses to an external separating device, represent
potential risks to the operation.
[0013] Due to the joint arrangement of both separating devices
within the same oil separating and recycling housing an internal
earthing of both components, moreover together with any further
components received in this housing, is possible. Static discharges
and flying sparks can be safely avoided in this way.
[0014] The sequentially connected separating devices in flow
direction offer a step-like separation.
[0015] The preferred accessibility of both separating devices via a
face wall of the oil separating and recycling housing has proven to
be favourable to handling, in particular with a preferred
one-behind-the-other arrangement of the separating devices, wherein
when viewed from the face wall the one separating device behind the
separating device initially visible from the face wall is at least
partially arranged to be hidden.
[0016] Further features of the invention will now, as well as in
the description of the figures, be explained in terms of their
preferred assignment to the subject of claim 1 or in relation to
features in further claims. But they may also be of importance in
terms of an assignment to merely individual features of claim 1 or
to the respective further claim or independently, respectively.
[0017] In one possible design the two separating devices may be
singly insertable and removable. Insertion/removal, as preferred,
may be performed in a specified order. Moreover removal of one
separating device may be dependent on the removal of the other
separating device.
[0018] In one alternative design the two separating devices may be
connected to each other for their combined joined insertion and
removal. Such a connection may be undone after a removal, for
example for replacing only one of the separating devices.
[0019] Insertion and removal may refer to the entire separating
unit (first and/or second separating device). In this respect
removal or insertion of only filter elements of the separating
devices is also possible. These filter elements may also be
accessible via the one face wall. Also this arrangement may be
chosen such that one separating device is completely removable from
the housing for maintenance or replacement, whilst with the second
separating device preferably only the associated filter element is
removable as part of the usual maintenance.
[0020] The gas path between the first separating device viewed in
gas flow direction and the second separating device viewed in gas
flow direction may be designed valvefree, as is preferred. This, as
is preferable, results in a transition without pressure loss from
the first separating device into the second separating device,
wherein in a preferred design the line section defining the gas
path between the separating devices is given through the oil
separating and recycling housing.
[0021] The length of the gas path in gas flow direction between the
first separating device viewed in gas flow direction may correspond
to a diameter dimension or less of the first separating device. The
length of the gas path can tend towards zero, for a direct (linear)
sequential arrangement of the two separating devices. The diameter
dimension of the first separating device preferably refers to a
maximum extension dimension in a cross-section transversely to the
longitudinal extension/transversely to the gas flow direction
within the separating device, here with regard to the filter
material serving the oil separation.
[0022] With a preferred circular-cylindrical design of the first
separating device/its separating filter, the maximum extension
dimension in cross-section is the diameter dimension. For an
exemplary cross-section of the filter material the previously
mentioned diameter dimension corresponds for example to the longest
extension dimension in the cross-section area.
[0023] The separating devices are fine separating or air/oil
separating elements, further so-called oil mist separators, wherein
the in-gas-flow-direction downstream second separating device
comprises a higher degree of separation compared to the first
separating device and thus a higher particle filter class.
[0024] Also, as preferred, the one or more monitoring and/or
maintenance units may be arranged in only three cover parts, which
are attached to the two face walls of the oil separating and
recycling housing, wherein the oil separating and recycling housing
may, by the way, be formed with sidewalls, a bottom wall, a ceiling
wall and face walls for a monitoring and/or maintenance unit.
[0025] The cover parts may be assigned to the face walls of the oil
separating and recycling housing. As such one face wall may be
configured for example as the rear side cover, and one service
cover may be assigned to a front face wall common used in
operation. In addition the service cover may have a maintenance
cover arranged on it, which is removable for maintenance
purposes.
[0026] Moreover the monitoring and/or maintenance units, further
preferably all monitoring and/or maintenance units relevant to
normal operation of the vacuum pump, may be provided in or on the
three cover parts. Furthermore, frequently used monitoring and/or
maintenance units may be provided in the service cover or in the
maintenance cover which can be arranged on the service cover/are
accessible via the same.
[0027] Essential functions are preferably situated within the area
of the three cover parts/can be performed within the area of these.
In particular these functions are oil filling and/or oil checking
and/or oil monitoring and/or oil draining and/or fastening of one
or both separating devices and/or providing access for the
maintenance of the one or both separating devices and/or fastening
of a float device and/or providing access to the float device
and/or providing space for separated oil and/or providing a return
for collected oil and/or a receptacle for the maintenance cover
and/or dividing the oil separating and recycling housing into an
upper and lower space and/or connecting an oil heater and/or
connecting a water cooler and/or connecting a filter and/or
connecting elements downstream of the vacuum pump and/or directing
discharged air into a defined direction.
[0028] The oil separating and recycling housing as such without the
above-mentioned cover parts is preferably without a relevant
function, at least as regards the user interface. V Thus this
housing may be constructed in a simple manner. As such the ceiling
wall and the bottom wall in particular, further preferably also at
least one external sidewall may be designed without any preparation
for arranging relevant devices.
[0029] The float device is generally a control for the through-flow
from the upper into the lower chamber. It is influenced in
particular by an oil level developing in the upper chamber.
Exceeding a certain predefined oil level shall be avoided. In the
following, for simplicity's sake, this device is always called
float device. The common return of the separated oil of both
separating devices into the oil circuit is effected via this float
device.
[0030] In a further design the one or more monitoring and/or
maintenance units may be arranged on a removable maintenance cover
of the oil separating and recycling unit, wherein when the
maintenance cover is removed, one or both separating devices and/or
a float device are accessible for maintenance.
[0031] The one or more monitoring and/or maintenance units may be
assigned to a housing area of the oil separating and recycling
unit, in which area a removable maintenance cover is formed. The
monitoring and/or maintenance units may be directly arranged/formed
on the maintenance cover, or as required in the direct vicinity of
the maintenance cover in the surrounding housing area. This leads
to a reduction in the space required for the rotary vane vacuum
pump in the installation and usage area. By removing the
maintenance cover from the oil separating and recycling housing
access to components of the oil separating and recycling unit is
made possible, in particular access to one or both separating
devices and/or a float device. Such a float device may be required
in order to allow the gas current to flow selectively through the
one or more separating units as a consequence of differences in
pressure in the area of the vacuum pump. This involves separated
oil being collected in a cavity preferably formed in a service
cover forming a face wall of the oil separating and recycling
housing. A hollow body is arranged in the cavity which may also be
called an oil-collecting chamber, the hollow body being connected
to a joint, preferably a rotary joint and a seal. The seal blocks
the return of the oil. As the oil level rises the hollow body
starts to float, and the joint causes the seal to be raised, which
frees an opening for the return of the oil.
[0032] The maintenance cover may be configured and arranged in such
a way that the oil behind it in the oil separating and recycling
housing cannot escape on removal of the maintenance cover, wherein
the maintenance cover may be arranged in the area of one face wall
of the oil separating and recycling housing. Or the maintenance
cover may be arranged on a service cover assigned to a face wall of
the oil separating and recycling housing.
[0033] As regards its longitudinal extension, the oil separating
and recycling housing may be comprised of a profile with a
consistent cross-section. Such a profile may be an extruded section
profile. This makes it possible to produce the housing of the oil
separating and recycling plant in a particularly economic manner.
The contour is preferably identical at each point of the
longitudinal axis of the housing part. With regard to an extruded
section profile an aluminum-wrought alloy is pressed through a
two-dimensional die, so that an elongated profile is produced,
which can be cut to the preferred length. This allows producing
such a housing with dimensionally stable contours over the entire
length.
[0034] The external surfaces may be formed optically clean and
even. Further working steps, in particular surface treatment steps,
may be omitted, in particular with a manufacture from an extruded
section profile. Moreover, as a result of the proposed construction
of the housing, the surface of the same may be presented as a
decorative element.
[0035] The consistent cross-section profile, preferably the
extruded section profile, offers the possibility of modifying the
volume of the oil separating and recycling unit and to adapt it to
the needs of the application.
[0036] Insofar as reference is made above and below to an extruded
section profile, it is, also in general terms, always to be
understood as a consistent section profile.
[0037] It may further be provided that the maintenance cover forms
part of a face wall of the oil separating and recycling housing or
the face wall in total. In the operating position of the vacuum
pump the face wall may be aligned with/face an operator or control
person. In a preferred design the maintenance cover covers an
opening provided in the face wall of the housing, through which for
example the one or both separating devices and/or the float device
are accessible for maintenance. As such the maintenance cover as
regards its cover surface, may be of a size, which corresponds to
0.25 to 0.5 times the outward-pointing end surface of the face
wall.
[0038] The separating devices, as regards the through-flow
direction, can be arranged in longitudinal direction of the oil
separating and recycling unit. Further, the separating devices, as
regards the through-flow direction, are preferably arranged in
longitudinal direction of the extruded section profile of the
housing.
[0039] Preferably the maintenance cover is arranged as an extension
of at least one of the separating devices in the area of the face
wall. A longitudinal centre axis of the separating device can, as
an extension of the same, pass through the maintenance cover in the
area of its broadside surfaces.
[0040] After removal of the maintenance cover the filter element,
preferably in form of a special filter mat, can be removed from the
separating device configured as a fine separating device. It can
then be simply replaced for example by a new filter element.
[0041] A sidewall is provided between the rotary vane power unit
and the oil separating and recycling unit. This may be the sidewall
of the oil separating and recycling housing. The sidewall may
comprise a through-opening, through which compressed gas with a
percentage of oil from the rotary vane power unit can enter into
the oil separating and recycling unit.
[0042] The gas entering with a percentage of oil can, in a first
portion of the oil separating and recycling unit, flow in
counter-direction to a second portion, in which second portion oil
separation, for example fine separation, takes place. The flow
direction, as preferred from now on, may be in longitudinal
extension of the oil separating and recycling housing, and thus as
further preferred, in longitudinal extension of the extruded
section profile. This is an essential flow direction from one end
region of the housing along its longitudinal extension to the other
end region of the housing, wherein deviations may be provided from
a strictly linear flow direction within this flow from one end to
the other end of the housing.
[0043] Below the through-opening a housing portion may follow
formed as a flow path, into which oil flows which has been
separated from the gas as a result of gravity and/or centrifugal
forces. This housing portion may serve as an oil sump, may thus be
configured as a kind of oil trough. A first separation of gas and
oil is preferably effected via a gravity and/or centrifugal force
separation.
[0044] In order to permit an oil change, possibly also a connection
of an oil cooling circuit, the housing portion has at least one oil
outlet opening. This may, as is preferred, be formed in the
vertically lowest area of the housing portion, when the vacuum pump
is in the installation and operating position. Further preferably
the oil outlet opening is closable.
[0045] The oil outlet opening may also be accessible from an face
wall of the oil separating and recycling housing. In a preferred
design the oil outlet opening is assigned to the face wall, on
which the maintenance cover is also arranged.
[0046] In order to, in particular, separate particles out of the
oil separated from the gas, an oil filter may further be provided
in the housing portion or assigned to the same, through which the
oil present in the housing portion can be directed. The oil filter
may preferably be an exchangeable oil filter.
[0047] The oil directed through the oil filter can preferably be
fed into the rotary vane chamber. To this end a pump may be
provided, which sucks the oil collecting in the housing portion in
through the oil filter and conveys it into the rotary vane chamber
of the rotary vane power unit. A design without pump is preferred,
and oil delivery is effected by making use of the pressure
difference between the oil collecting chamber and the working space
of the vacuum pump.
[0048] A filter mat may be provided in the fine separating device
(first separating device). This filter mat is preferably
replaceable, wherein in a preferred design, such a replacement is
performed from the one face wall comprising the maintenance cover,
following removal of the maintenance cover.
[0049] The filter mat may be tube-shaped with an inner flow path
for the gas/oil mixture. Oil separated in the fine separating
device flows, in a preferred design, via the post-separator (second
separating device) and via the float device into the housing
portion comprising the oil collecting chamber.
[0050] The flow resistance of the filter elements (filter mat) in
the separating devices results in a pressure difference in front of
and behind the fine separating device. This may be up to 400 mbar
depending on the volume current currently delivered by the
pump.
[0051] The float device may be formed directly on the maintenance
cover or preferably be accessible after removal of the maintenance
cover. This also offers an improvement in maintenance.
[0052] Also an oil level indication may be provided on the face
wall, in or on the maintenance cover, as required. The oil level of
the vacuum pump can be read therefrom. This may be a conventional
sight glass or alternatively an analogue or digital measurement
value display.
[0053] Further, an overpressure valve or a bursting disc may be
arranged, as required, on the face wall or in the maintenance
cover. Such an overpressure valve or bursting disc serves as a
safeguard against a sudden overpressure in the appliance. In case a
bursting disc is arranged in the maintenance cover, a safe
operating state may be reinstated after an event in a simple manner
regarding handling, for example by, in total, changing the
maintenance cover.
[0054] In a further design a temperature monitoring element may be
arranged in the face wall, as required, in the maintenance cover or
associated with the maintenance cover. This in particular serves
monitoring of the oil temperature.
[0055] The gas separated out of the oil may in a possible design
exit through the face wall, further for example through the
maintenance cover. To this end the face wall, in particular the
maintenance cover, comprises an appropriate outlet opening.
[0056] In one possible design the maintenance cover comprises a gas
outlet connection. This may be arranged for connection to a sound
absorber or a continuation element. As such the gas outlet
connection, in a first design of the maintenance cover, may be
provided with a thread. This may be used for connection to outlet
piping. The thread may also be used for connection to a bursting
disc. As required, the bursting disc may also be arranged and
fastened in the outlet piping. If required a pipe line, a sound
absorber or other gas conducting elements may be connected. By
changing the maintenance cover an appropriately equipped
maintenance cover may be arranged if the appliance is situated at
the place of use.
[0057] In a further design the gas outlet connection may be
provided with a possibly removable redirecting cap, in which the
exiting gas is redirected by at least 60.degree. with regard to a
given outlet direction. Preferably redirection is chosen such that
the exiting gas flows out in downward-direction. As a result noise
pollution in operation of the vacuum pump is reduced because the
sound is directed in a direction towards the bottom. The gas outlet
connection may also be arranged so as to be rotatable on the
maintenance cover, so that for example redirection to the side or
towards the top is possible.
[0058] The oil separating and recycling housing may comprise
integrally formed chambering comprising an upper and a lower
chamber with, in the installation state as regards gravity, an
upper and a lower chamber, wherein in longitudinal direction of the
oil separating and recycling housing a face wall may be connected
at the front and at the back. As part of the preferred manufacture
of the housing the integral forming of chambers may be produced
from an extruded section profile. The upper chamber, in the
preferred design, serves, in particular, to receive the separating
devices, whilst the chamber which is the lower chamber when the
vacuum pump is in operation, constitutes the previously described
housing portion. The face walls to be connected each form an
end-side termination of the oil separating and recycling housing.
One of the face walls may comprise an opening covered by the
previously described maintenance cover.
[0059] At least one face wall preferably constitutes a connection
of the chambers. With a preferably counter-directed flow within the
chambers at least one face wall may constitute gas-redirection
regions.
[0060] The through-opening from the rotary vane power unit/from the
rotary vane chamber to the oil separating and recycling unit leads,
in a preferred design, into the lower chamber of the oil separating
and recycling housing. This through-opening is joined, when viewed
in flow direction, to the gravity and/or impact separator.
[0061] Further the lower chamber, in a preferred design constitutes
an oil collecting container.
[0062] One or more cooling lines preferably integrated in the
extruded section profile may be provided assigned to the oil
collecting container. Inlets and outlets for cooling the oil by
means of an external cooler may also be provided in the area of the
oil collecting container.
SHORT DESCRIPTION OF THE DRAWINGS
[0063] The invention will now be explained in detail by way of the
attached drawing, which merely represents an exemplary embodiment
and in which
[0064] FIG. 1 shows an oil-lubricated rotary vane vacuum pump in a
perspective view;
[0065] FIG. 2 shows a respective top view;
[0066] FIG. 3 shows the vacuum pump in a side view, looking at a
face wall with the maintenance cover;
[0067] FIG. 4 shows the section as per line IV-IV in FIG. 3;
[0068] FIG. 5 shows the section as per line V-V in FIG. 2;
[0069] FIG. 6 shows a perspective detail view of the oil separating
and recycling housing;
[0070] FIG. 7 shows a perspective detail view of the face wall with
associated maintenance cover and a gas outlet connection attachable
to the maintenance cover;
[0071] FIG. 8 shows a perspective detail view of the maintenance
cover, looking at the inner surface when in use;
[0072] FIG. 9 shows a sectional view of the oil separating and
recycling housing;
[0073] FIG. 10 shows the section as per line X-X in FIG. 2.
DESCRIPTION OF THE EMBODIMENTS
[0074] What is shown and described, initially with reference to
FIG. 1, is an oil-lubricated rotary vane vacuum pump 1 with a
rotary vane power unit and an oil separating and recycling unit
3.
[0075] The rotary vane power unit 2 comprises a power unit housing,
in which a rotary vane chamber 5 with a rotary vane rotor 6 are
arranged. The power unit housing is covered by a hood 4 and side
covers 11 and 12 arranged respectively, at the end with reference
to a longitudinal axis.
[0076] The rotary vane chamber 5 is configured as a cylindrical
bore in the power unit housing. The rotary vane chamber 5 comprises
a longitudinal extension, which orients itself on the bore axis of
the rotary vane chamber 5.
[0077] The cylindrically shaped rotary vane rotor 6 is
eccentrically arranged relative to the rotary vane chamber 5.
Correspondingly, the rotor axis x extends in parallel, but offset
to the chamber axis.
[0078] The rotary vane rotor 6 comprises several, in the exemplary
embodiment three slides 7. These are arranged in a slidably movable
manner in approximately radially aligned slots 8 of the rotor 6
when viewed in cross-section. Due to the rotation of the rotary
vane rotor 6 as a result of the centrifugal force the slides 7 are
pressed against the wall bounding the rotary vane chamber 5.
[0079] In operation of the vacuum pump 1 the rotary vane rotor 6
rotates radially offset to the centre axis of the rotary vane
chamber 5, this in consequence of being driven via a motor
rotatingly impacting the rotor shaft, in particular electric motor
9. This results in closed chambers 10, separated by the radially
movably arranged slides 7, wherein the size of the chambers changes
during a revolution of the rotary vane rotor 6.
[0080] The rotary vane chamber 5 is closed on either side with
regard to its longitudinal axis by rotary vane covers 46 and 47
(see FIG. 10).
[0081] Outside the power unit housing, for example associated with
the side cover 12, the electric motor 9 is preferably fastened to
the power housing. The shaft of the rotary vane rotor 6 may extend
through the respective side cover 12 in order to permit
torque-proof engagement of the electromotor 9.
[0082] Changes in the size of chambers 10, when the vacuum pump is
in operation results in pressure differences between the individual
chambers 10 and thus between the inlet side and the outlet side of
the thus formed blower.
[0083] The drive via the electric motor 9 may be arranged directly
on the rotor shaft or, as further preferred, via a coupling.
[0084] Oil-lubricated rotary vane power units are characterized in
that with these oil is introduced into the rotary vane chamber 5.
This oil leads to gaps between the different components becoming
blocked, in particular between the slides 7 and the wall of the
rotary vane chamber 5. The exchange of gas between the different
chambers 10 is thus obstructed. In this way, during operation,
higher vacuums are achieved than is possible with dry-running
rotary vane pumps.
[0085] Depending on the construction the oil together with the
conveyed gas is conveyed out of the last chamber 10 of the rotary
vane power unit 2. In addition the oil is heated due to the
compression enthalpy in the system. Since the oil comes into
contact with the conveying medium (gas), this may contaminate or
may change due to possible chemical reactions.
[0086] The oil flows in a cycle process through the vacuum pump 1.
This means that after it has left the rotary vane power unit 2, it
must be recycled. The oil separating and recycling unit 3 serves
this purpose.
[0087] The unit 3 is connected to the rotary vane power unit 2 so
that a unit is formed consisting of rotary vane power unit 2, oil
separating and recycling unit 3 and electric motor 9.
[0088] The oil separating and recycling unit 3 to begin with
comprises an oil separating and recycling housing 13, with
sidewalls 14, 15, a bottom wall 16, a ceiling wall 17 and face
walls 18, 19.
[0089] The face walls 18 and 19, viewed in longitudinal extension
of the housing 13, which longitudinal extension corresponds to the
longitudinal extension of the rotary vane power unit 2, are
arranged at either end of the housing integrally formed by the
sidewalls 14 and 15, the bottom wall 16 and the ceiling wall 17, in
particular are connected by screws to the housing. The face wall 18
is preferably formed by a service cover and the face wall 19 is
formed by a rear side cover.
[0090] The housing 13, as regards its longitudinal extension, may
consist of an extruded section profile 20, in particular of an
aluminum extruded section profile. The oil separating and recycling
housing 13 comprises an essentially consistent cross-section over
its length, when viewed along its longitudinal extension while
maintaining a dimensionally stable contour. Moreover during
manufacture of the housing 13 by means of an extrusion process the
external surfaces are designed optically uniform and clean so that
surface treatment steps for optical improvement of the surface may
be omitted. Provision need merely be made for necessary machining
steps such as breakthroughs in the sidewalls and/or bottom wall
and/or ceiling wall.
[0091] Also manufacture of the housing 13 by means of an extrusion
process may be utilized such that apart from the surface the shape
of the housing may be configured such that in the end this defines
the design characterizing element.
[0092] The sidewalls 14 and 15 extend transversely to a rotation
plane of the rotary vane rotor 6, wherein in the embodiment shown
the sidewall 14 also represents the fastening plane for fastening
the oil separating and recycling housing 13 in the power unit
housing.
[0093] The face wall 18 arranged at the end finishes flush with the
adjacent side cover 11 on the external side of the wall in one
possible embodiment, and the same preferably goes for the ceiling
wall 17 and the bottom wall 16 with the adjoining adjacent wall
portions of the power unit housing. This results in a compact and
optically pleasing unit.
[0094] The external surface of the sidewall 15 facing away from the
rotary vane power unit 2 and thus facing the outside is shaped in a
corrugated manner (see FIG. 9 in particular) as regards a
cross-section in the rotation plane of the rotary vane rotor 6.
When viewed in cross-section across the extension length of the
sidewall 15, this results in uniform rounded elevations, which are
connected with each other via valleys. This results in an
enlargement of the surface in the area of the sidewall 15 and thus
in an improvement of the heat dissipation in operation of the
vacuum pump 1.
[0095] The corrugated surface in a preferred design continues in
the facing surface areas of the face walls 18 and 19.
[0096] The oil separating and recycling housing 13 comprises a
preferably integrally formed chambering. With regard to an
installation state, as depicted, this results, as regards gravity,
in a lower chamber 21 and an upper chamber 22. The division of the
chambers 21 and 22 is achieved by a separating bar 23 extending
transversely to the sidewalls 14 and 15 with regard to a
cross-section as per FIG. 9.
[0097] In operation of the vacuum pump 1, separation of oil and gas
takes place in particular in the oil separating and recycling
unit.
[0098] To this end to start with a gravity and/or impact separator
24 and a downstream (in gas flow direction) two-stage separator are
provided, which is composed of a first separating device T.sub.1 in
form of a fine separating device 25 and a downstream second
separating device T.sub.2 in the form of a post-separating device
43.
[0099] The oil/gas mixture enters from the rotary vane power unit 2
via through-opening 26 in the area of the sidewall 14 into the oil
separating and recycling unit 3.
[0100] With the entry into the unit 3 a coarse separation of large
oil drops through the gravity and/or impact separator 24 takes
preferably place initially as a consequence of redirection of the
gas/oil mixture and a slow-down of the flow.
[0101] The entry of the oil/gas mixture into the unit 3 takes place
in consequence of a respective arrangement of the through-opening
26 in the area of the lower chamber 21, in which accordingly a
separating device T.sub.3 may be arranged, such as in the form of a
gravity and/or impact separator 24.
[0102] The housing portion 27 resulting below the through-opening
26 in the area of the lower chamber 21 serves like a kind of oil
trough in which an oil sump collects. Thus an oil collecting
container is formed in the lower chamber 21.
[0103] Further, the lower chamber 21 forms a flow path with a flow
a oriented in longitudinal direction of the housing. This flow a is
directed in direction of the rear face wall 19.
[0104] In order to avoid that the gas flow stirs up the oil
collecting in the oil sump, the area of the oil trough is covered
by a pulled-in filter sheet 44.
[0105] The inside of the face wall 19 is configured for redirecting
the flow from the lower chamber 21 into the upper chamber 22, in
which the flow path formed in the upper chamber 22 permits a flow b
in the opposite direction to flow a in the lower chamber 21.
[0106] The separating devices T.sub.1 and T.sub.2 are provided in
the upper chamber 22 in a linear one-behind-the-other
arrangement.
[0107] The fine separating device 25 (separating device T.sub.1)
comprises a tube-shaped filter mat 42, the tube axis of which is
preferably pointing in the same direction as the rotor axis x of
the rotary vane rotor 6. Further the fine separating device 25 is
essentially arranged oriented in longitudinal direction of the oil
separating and recycling housing 13.
[0108] In gas flow direction b downstream of the fine separating
device 25 a post-separating device 43 is provided in the upper
chamber 22. The gas exiting from the fine separating device 25 is,
of necessity, guided through the post-separating device 43. The
length c of the gas path between the first separating device
T.sub.1 (fine separating device 25) viewed in gas flow direction b
and the second separating device T.sub.2 (post-separating device
43) viewed in gas flow direction b approximately corresponds to a
fourth to third of the diameter dimension of the first separating
device T.sub.1 (with regard to the largest cross-section extension
dimension of the filter-effective element).
[0109] The oil-gas mixture redirected from the lower chamber 21
into the upper chamber 22 is selectively and successively guided
through the two separating devices T.sub.1 and T.sub.2, wherein a
pressure difference results in front of the first separating device
T.sub.1 and behind the second separating device T.sub.2, which
depending on the delivery pressure of the rotary vane power unit 2
may be up to 400 mbar.
[0110] Furthermore an oil foam degradation device may be provided
in the oil separating and recycling unit 3.
[0111] Moreover an oil filter 28 is provided. This may be arranged
assigned to the floor area of the oil separating and recycling
housing 13, further preferably to the rear face wall 19. The oil
present in the oil sump is sucked-in through the oil filter 28 and
in particular freed from solid particles.
[0112] Utilizing the pressure difference between the lower chamber
21 and the chamber 10 in the rotary vane power unit 2 the oil
filtered in the oil filter 28 is conveyed via the suction line 29
into the rotary vane power unit 2.
[0113] By means of an external cooler not shown cooling of the in
particular filtered oil can be performed. To this end respective
inlets and outlets are provided in the area of the lower chamber
21.
[0114] Cooling paths can also be provided in the profile of the
housing 13, for example in the area of the bottom wall 16 and/or
the sidewalls 15 (assigned to the lower chamber 21).
[0115] The face wall 18 preferably facing an operator when in use
leaves a passage on the inside of the wall for connection of the
upper chamber 22 to the lower chamber 21, which passage is formed
by a float device 30. Oil separated at the two separating devices
T.sub.1 and T.sub.2 is directed back into the reservoir in the area
of the lower chamber 21, this through the float device 30. Due to
the above-described pressure difference in front of and behind the
separating devices T.sub.1 and T.sub.2 this prevents gas entering
through the through-opening 26 into the lower chamber 21 from
flowing in a bypass-like manner directly to the gas outlet 31.
[0116] In addition an oil bath heater may be provided in order to
heat the oil prior to the start of the vacuum pump 1.
[0117] Moreover additional water cooling may be provided.
[0118] The oil bath heater and/or water cooling may be arranged on
the face wall 19.
[0119] In the face wall 18 facing away from the electric motor 9
and forming a front side when in operation a window-like opening 32
extending at least approximately over the entire cross-section
surface of the upper chamber 22 and assigned to the upper chamber
22 may be provided. This window opening is closed by a maintenance
cover 33 when the vacuum pump 1 is in operation. The maintenance
cover 33 may be screwed to the face wall 18, preferably via a
seal.
[0120] The gas outlet 31 is provided in the maintenance cover 33.
To this end the maintenance cover comprises a through-opening 34,
to which a gas outlet connection 35 can be connected on the outside
of the wall of the maintenance cover 33.
[0121] The gas outlet connection 35 may be configured as a
removable redirecting cap 36, in which the exiting gas, as regards
its alignment given by the gas outlet connection, the alignment
being essentially the same as the flow b in the upper chamber 22,
is directed by at least 60.degree., preferably up to 90.degree., in
a downward direction towards the plane given by the bottom wall 16.
As a result the sound is directed towards the bottom, which leads
to a reduction in noise pollution.
[0122] Preferably the gas outlet connection 35 is rotatably
arranged on the maintenance cover 33, so that the exhaust air can
be selectively directed for example also to the side or towards the
top.
[0123] The redirecting cap 36 can be replaced, for example, by a
gas outlet connection for connection to a sound absorber or a
continuation element.
[0124] Moreover a maintenance cover 33 with redirecting cap 36 may
be replaced by a maintenance cover 33 for connection for example to
external piping.
[0125] The oil separating and recycling unit 3 comprises a number
of monitoring and/or maintenance units 37. As such an oil level
indication 38 for determining the oil quantity may be provided in
the face wall 18, assigned to the lower chamber 21. The oil level
indication 38 may be formed by an oil sight glass and/or an
electrical oil level sensor.
[0126] Also a possible oil temperature indication may be arranged
in the area of the face wall 18.
[0127] Further both the flow and the return for changing the oil in
the oil separating and recycling unit 3 may be provided in the face
wall 18. To this end an oil outlet opening 39 and a fill-in
connection 40 are provided in the face wall 18 in one design.
[0128] After removal of the maintenance cover 33 assigned to the
face wall 18 both separating devices T.sub.1 and T.sub.2 and the
float device 30 are accessible for maintenance and, as required,
replacement from the operating side of the vacuum pump 1.
[0129] As such following removal of the face wall 18 the separating
device T.sub.2 (post-separating device 43) is initially exposed.
This can then be removed from the upper chamber 22. The
post-separating device 43 may be fastened for example on a
carriage-type frame 45. The post-separating device 43 in one design
can be removed from the upper chamber 22 together with the frame
45, whereafter the filter mat 42 of the fine separating device 25
is also free for removal/the filter mat 42 can be accessed for
maintenance purposes.
[0130] The gas path between the two separating devices T.sub.1 and
T.sub.2 is designed without valves, and in the depicted embodiment,
with regard to solely one cross-section, is surrounded by the
material of the oil separating and recycling housing 13 in the area
of the upper chamber 22.
[0131] The post-separating device 43 may comprise a filter mat or
the like, which is essentially permeable in flow direction b.
[0132] In addition an overpressure valve may be arranged in the
maintenance cover 33.
[0133] The overpressure valve serves as a safeguard against a
sudden overpressure in the oil separating and recycling unit 3; is
thus preferably part of the monitoring unit.
[0134] The face walls 18 and 19 as well as the maintenance cover 33
are, as cover parts A, B and C, assigned directly or indirectly
(cover part C/maintenance cover 33) to the oil separating and
recycling housing 31.
[0135] As a consequence of the above-described arrangement of the
monitoring and/or maintenance units 37 as well as of the design of
the over parts A, B and C, preferably all interfaces are
accommodated in an easily accessible manner in the area of the face
walls 18, 19, so that the space requirement for the appliance is
reduced, thereby increasing ease of maintenance and simplifying
manufacture of the oil separating and recycling housing.
[0136] The above statements serve to explain the inventions covered
in total by the application, wherein the inventions further develop
the state of the art, at least due to the following feature
combinations, also on their own, respectively, i.e.
[0137] A rotary vane vacuum pump 1, which is characterized in that
the gas within the oil separating and recycling housing 13 flows in
succession through two separating devices T.sub.1, T.sub.2, both of
which are accessible for maintenance from a face wall 18.
[0138] A rotary vane vacuum pump 1, which is characterized in that
both separating devices T.sub.1, T.sub.2 are singly insertable and
removable.
[0139] A rotary vane vacuum pump 1, which is characterized in that
both separating devices T.sub.1, T.sub.2 are connected to each
other, combined for joint insertion and removal.
[0140] A rotary vane vacuum pump 1, which is characterized in that
a gas path is formed without valves between the separating device
T.sub.1 which is first in gas flow direction b and the separating
device T.sub.2, which is second in gas flow direction b.
[0141] An oil-lubricated rotary vane vacuum pump 1, which is
characterized in that the length c of the gas path between the
separating device T.sub.1 which is first in air flow direction and
the separating device T.sub.2 which is second in air flow direction
b corresponds to a diameter dimension or less, of the first
separating device T.sub.1.
TABLE-US-00001 List of reference symbols 1 vacuum pump 2 rotary
vane power unit 3 oil separating and re- cycling unit 4 hood 5
rotary vane chamber 6 rotary vane rotor 7 slide 8 slot 9 electric
motor 10 chamber 11 side cover 12 side cover 13 oil separating and
re- cycling housing 14 sidewall 15 sidewall 16 bottom wall 17
ceiling wall 18 face wall 19 face wall 20 extruded section profile
21 lower chamber 22 upper chamber 23 separating bar 24 gravity
and/or impact separator 25 fine separating device 26 through
opening 27 housing portion 28 oil filter 29 suction line 30 float
device 31 gas outlet 32 opening 33 maintenance cover 34 through
opening 35 gas outlet connection 36 redirecting cap 37 monitoring
and maintenance unit 38 oil filter indication 39 drain opening 40
fill-in connection 42 filter mat 43 post-separating device 44
filter sheet 45 frame 46 rotary vane side cover 47 rotary vane side
cover a flow b flow c length x rotor axis A cover part C cover part
T.sub.1 separating device T.sub.2 separating device T.sub.3
separating device
* * * * *