U.S. patent application number 11/531362 was filed with the patent office on 2007-03-15 for device for the performance adaptation of a liquid ring pump.
Invention is credited to Fausto Olivares, Peter Trimborn, Christoph Weber.
Application Number | 20070059185 11/531362 |
Document ID | / |
Family ID | 37461462 |
Filed Date | 2007-03-15 |
United States Patent
Application |
20070059185 |
Kind Code |
A1 |
Olivares; Fausto ; et
al. |
March 15, 2007 |
Device for the Performance Adaptation of a Liquid Ring Pump
Abstract
For a device (4) for the performance adaptation of a liquid ring
pump, said liquid ring pump (1) comprising a cylindrical workspace
(6) for conveying a conveyed fluid (15) between an intake socket
(16a) and a pressure socket (18a). The device (4) comprises a
control unit (28), control line (22) and a control element (26)
connected with the workspace (6). The device is designed to vary
the amount of operating liquid of the liquid ring pump (1) during
operation (running) of said pump. Also, a method for adapting the
performance of the liquid ring pump (1), which is performed in
particular via the device (4) is specified.
Inventors: |
Olivares; Fausto; (Sulzbach,
DE) ; Weber; Christoph; (Nurnberg, DE) ;
Trimborn; Peter; (Feucht, DE) |
Correspondence
Address: |
BARNES & THORNBURG LLP
P.O. BOX 2786
CHICAGO
IL
60690-2786
US
|
Family ID: |
37461462 |
Appl. No.: |
11/531362 |
Filed: |
September 13, 2006 |
Current U.S.
Class: |
417/68 |
Current CPC
Class: |
F04C 19/004 20130101;
F04C 19/001 20130101 |
Class at
Publication: |
417/068 |
International
Class: |
F04C 19/00 20060101
F04C019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 13, 2005 |
DE |
102005043434.7 |
Claims
1. A device (4) for performance adaptation of a liquid ring pump
(1), said pump: comprising a cylindrical workspace (6) for
conveying a conveyed fluid (15) between an air intake socket (16a,
16b), and a pressure socket (20a, 20b), wherein the workspace is
adapted to receive an operating fluid (5) which generates a liquid
ring (5a) during operation of the liquid ring pump (1), said device
comprising comprising a control element; a control line and a state
of operation wherein during operation said control line is in fluid
communication with said operating fluid (5), said control element
is actuated to release an amount of operating liquid through said
control line while the pump (1) is in operation, said operating
liquid is not immediately circulated back into said liquid ring
pump, said liquid being released is in addition to any liquid being
discharged through said outlets (20a, 20b)
2. The device according to claim 1, characterized in that a control
unit (28) is interfaced with said control element, wherein said
control unit cooperates in the actuation of said control
element.
3. The device according to claim 2 characterized in that the
control unit (28) is interfaced with at least one sensor (30),
wherein in said state of operation, said control unit cooperates in
the actuation of said control element in dependence upon
information received from said at least one sensor (30).
4. The device according to claim 3 characterized in that the sensor
is a pressure sensor disposed along a pathway (70) in which
conveying fluid (15) enters inlet (16a, 16b), said sensor upstream
of said inlet.
5. The device according to claim 4 characterized in that said
device includes at least one additional sensor for sensing
temperature, said temperature sensor also located along said
pathway.
6. A device according to one of claim 1 characterized in that said
control line during said state of operation receives operating
liquid from a shutdown or total drain outlet (2).
7. The device according to claim 6 characterized in that said
control line receives operating fluid during said state of
operation from a total discharge line (2a), said discharge line in
fluid communication with said total drain outlet (2).
8. The device according to claim 7 characterized in that said total
drain outlet includes a first outlet at a drive end side of the
pump and a second outlet at a non-drive end side of the pump,
wherein said control line is interfaced with said first and second
outlets such that during said state of operation, said control line
receives operating liquid through both outlets.
9. A device according to one of claim 1 characterized in that said
control line during said state of operation receives operating
liquid from at least one internal shaft seal supply aperture
(3).
10. The device according to claim 9 characterized in that said
inner shaft seal aperture includes a first opening at a drive end
side of the pump and a second opening at a non-drive end side of
the pump, wherein said control line is interfaced with said first
and second openings such that during said state of operation, said
control line receives operating liquid through both openings.
11. A method for performance adaptation of a liquid ring pump (1),
said pump comprising a cylindrical workspace (6) for conveying a
conveyed fluid (15) between an air intake socket (16a, 16b) and a
pressure socket (20a, 20b) wherein the workspace is adapted to
receive an operating fluid (5) which generates a liquid ring (5a)
during operation of the liquid ring pump (1), said method
characterized by: varying a hydraulic characteristic of the liquid
ring pump (1) as control variable.
12. The method, according to claim 11, characterized by actuating a
control element (26) interfaced with a control line (22) to release
a determined amount of operating fluid (5) through said line while
the pump (1) is in operation, said liquid being released is in
addition to any liquid being discharged through said pressure
socket; a. refraining from immediately circulating said operating
fluid back into a workspace of a liquid ring pump.
13. The method, according to claim 12 characterized by affecting
the actuation of said control element (26) by a control unit
28.
14. The method, according to claim 13 characterized by actuating
said control element (26) in dependence upon information received
from at least one sensor (30).
15. The device according to claim 14 characterized in that the
sensor is a pressure sensor disposed along a pathway in which
conveying fluid enters inlet (16a, 16b), said sensor upstream of
said inlet.
Description
[0001] We hereby claim foreign priority under section 119 of the US
Patent statute, based on German application 102005043434.7, filed
Sep. 13, 2005.
FIELD
[0002] The invention relates to a device for the performance
adaptation of a liquid ring pump, said pump comprising a
cylindrical workspace for conveying a conveyed fluid between a
fluid inlet (intake socket) and a fluid outlet (pressure socket),
wherein an operating fluid is contained in the workspace, said
device controls the volume of operating liquid in the pump during
operation of the pump.
BACKGROUND
[0003] A liquid ring pump is suitable for conveying dry or
liquid-containing gases and is commonly used both as a vacuum pump
and also as a compressor. A liquid ring pump of this type has an
impeller eccentrically arranged inside a casing that contains an
operating fluid. Water is often used as the operating fluid. During
operation of the pump, the rotation of the impeller causes the
operating fluid in the pump casing to form a liquid ring that lifts
off on the suction side from an impeller hub of the impeller and
revolves with the same. The liquid ring cooperates with the
impeller to draw in fluid at the inlet, compress the fluid, and
discharge it at the outlet. Due to the pump principle, the conveyed
fluid when discharged via the pressure socket (outlet) is mixed
with the operating fluid. The operating fluid is subsequently
separated from the conveyed gas in a separator and fed back to the
pump. The operating liquid in some pump arrangements can also serve
to seal spaces between the shaft, impeller and plate port of a
pump. A liquid ring pump is revealed, for example, in the printed
publication U.S. Pat. No. 4,392,783.
[0004] Industrial processes in vacuum and pressure applications,
within the framework of which liquid ring pumps are employed, are
often subject to periodical and also non-periodical changes. As a
result, the performance requirement placed on the given liquid ring
pump generally changes as well. Liquid ring pumps, however, for the
benefit of a simple design, often are not controllable or
adjustable with respect to their driving power. Liquid ring pumps
of this type are often sized for maximum load or maximum process
requirements, and they therefore typically draw, too much driving
power during normal operation. In the vast majority of existing
installations, the excess power of the liquid ring pumps is reduced
by means of a throttle regulation, false air, or bypass regulation.
The excess driving power is simply disposed of in these cases.
[0005] Some modern systems employ liquid ring pumps that regulate
the power requirement during changing process conditions via a
speed adaptation by means of a converter. However, converters
consume a certain amount of the conserved energy through electrical
losses. Additionally, the use of a converter disadvantageously
entails a comparatively high investment expenditure, additional
space requirement, and increased susceptibility to failure.
SUMMARY
[0006] The invention is therefore based on the object of providing
a device for the performance adaptation of a liquid ring pump, as
well as a method carried out especially by said device for the
performance adaptation of the liquid ring pump.
[0007] Accordingly, one embodiment of the device comprises a
control line interfaced with a control element. The control line is
fluidly connected to the workspace or chamber of the pump. The
control line and element are designed to modify, as a correcting
variable, a hydraulic characteristic of the liquid pump. The
modified characteristic is preferably the volume of operating
liquid in the chamber during operation (running) of the pump.
[0008] As an alternative to the variation of the quantity of
operating fluid, or in combination therewith, the device could be
designed to modify the viscosity of the operating fluid contained
in the workspace.
[0009] To regulate and change the volume of liquid during operation
of the pump, one embodiment of the invention uses a control line
fluidly connected to the total drain connection or outlet(s).
Standard pumps generally have a total drain connection allowing for
the drainage of the operating fluid from the pump when the pump is
not in operation i.e., shut down. The control line cooperates with
a control element (valve) which is interfaced with a control unit.
The control unit actuates the valve of the control line based on
input from one or more sensors or other actuators which monitor
process parameters. The sensors could be process pressure,
temperature, flow volume, or humidity sensors disposed at, in or up
stream of the fluid inlet intake socket. Moreover, the volume of
process liquid and/or dry content of the product can also be used
as a process parameter. The actuator, in addition to sensors, could
include a push button on the control unit. The push button
activates the valve to release a predetermined amount of operating
liquid during operation.
[0010] The control unit compares the actual value or values to a
pre-set value or values for the process parameters and discharges a
volume of operating fluid during operation to bring the actual
values in line with the pre-set values. Therefore, the use of a
control unit is advantageous in that it allows for the regulation
of the pump by taking into account process parameters such as the
physical characteristics of the conveyed fluids, one such
characteristic being process pressure. It also, of course, allows
one to take into account other process variables such as
temperature.
[0011] As an alternative to the use of a control unit, the
controlling element, such as the valve, may be activated manually.
The control element may also be activated, pneumatically or
hydraulically by signals from the control unit or from other
means.
[0012] As an alternative to using the total drain connections
(total outflow disposed at the bottom of the workspace), the
control line is interfaced with one or more of the internal shaft
sealing supply connections present in known pumps. In this case,
fluid is removed during operation through these sealing supply
connections.
[0013] As a further alternative, the control line is interfaced
with the pump by providing a unique connection in the pump for the
control line.
[0014] The object is additionally met according to the invention
with a method. The above explanations regarding advantages and
embodiments of the inventive device shall be logically translated
to a method for controlling the performance of a liquid ring
pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] To explain the device and method in more detail, example
embodiments of the invention are described below and in the
drawings:
[0016] FIG. 1 is a cross sectional view of a liquid ring pump
having suitable standard connections for interfacing with an
embodiment of our device for performance adaptation of a liquid
ring pump; the shown pump includes an impeller bounded on each
axial side by a port plate, each port plate being coupled to an end
shield.
[0017] FIGS. 1a, and 1b are front plan views of the end shields
shown in FIG. 1.
[0018] FIG. 2 is a stripped down schematic diagram showing an
embodiment of our device interfaced with a liquid ring pump.
[0019] FIG. 3 is a stripped down schematic diagram showing our
device interfaced with a liquid ring pump.
[0020] FIG. 4 is a stripped down schematic illustration of a pump
arrangement comprising a liquid ring pump and our device for the
performance adaptation of the liquid ring pump, said device
comprising a control line discharging into the total outflow
connection of the pump.
[0021] FIG. 5 is a stripped down schematic illustration according
to FIG. 4 of a variant of the device wherein the device for the
performance adaptation additionally incorporates a control line
interfaced with the peak of the workspace of the pump.
[0022] FIG. 6 is a schematic depiction according to FIG. 5 of an
additional variant of the pump device.
DETAILED DESCRIPTION
[0023] FIG. 1 shows a liquid ring pump 1 which has an approximately
cylindrical workspace 6, total drain connections or outlets 2 and
inner shaft seal supply connections or apertures 3. The workspace
has a central axis 40 and is radially surrounded by housing 41 The
connections or apertures 2 and 3 are suitable for interfacing with
the device or assembly 4 for controlling the volume of operating
fluid 5 in the workspace or operating chamber 6 of liquid ring pump
1. The operating/sealing supply liquid inlets 7 are also shown. The
pump also includes an impeller 11 supported eccentrically relative
to the workspace 6 with impeller blades 11a and hub 11b, and a
shaft 12. In the axial direction, the workspace 6 is bounded by
port plates 21a, 21b which are coupled to end shields 18a, 18b. The
end shields are symmetrical with each other. The end shields each
have inlets 13 to internal shaft seal connections 3. The work space
6 is filled with operating liquid 5. The operating liquid or fluid
5 is usually water. See FIG. 4. The operating fluid or liquid 5 can
serve to seal the interstices 43 between impeller 11, shaft 12 and
port plates 21a, 21b.
[0024] In operation, the impeller rotates in the direction 14. An
amount of conveyed fluid 15 is drawn into inlets 16a, 16b of end
shields or heads 18a, 18b. The conveyed fluid 15 exits outlets 20a,
20b.
[0025] In more detail, during operation of the pump, the impeller
blades or vanes 11a force the operating fluid 5 into a fast
rotating movement so that the operating fluid 5, under action of
the centrifugal force, forms a liquid ring 5a that is concentric
relative to the workspace 6. As a result of the eccentric mounting
of the impeller 11, a sickle-shaped space 6b is created between the
liquid ring 5a and impeller 11 within which conveyed fluid 15 is
transported in the direction of rotation 14. The conveyed fluid 15
is a dry or wet gas.
[0026] Now referring to FIG. 2, the interface of device 4 with a
total drain or shutdown drain connection 2 can be seen. The device
4 includes a control line, pipe or conduit 22. The line 22 is
interfaced with total drain line 2a by way of a two way valve 24.
Total drain line 2a is at the drive end. For reference end shield
18a is located at the drive end. Line 22 is also interfaced with a
control element 26 downstream of valve 24. The control element may
be an electronically or mechanically actuated valve.
[0027] Control element 26 is interfaced with control unit 28.
Interfaced with control unit 28 is sensor or sensors 30. The sensor
or sensors 30 can be for sensing process pressure, temperature,
humidity or flow volume. Sensors 30 can be located up stream, at,
or in fluid inlets 16a, 16b. Arranging the sensor(s) at the intake
socket, i.e., on the suction side, is particularly advantageous, as
the values for pressure, volume flow, temperature and humidity of
the conveyed fluid are not yet influenced and distorted through
pressure loss, leakage, or diffusion of the operating fluid into
the conveyed fluid. In this embodiment, it is also shown that the
control unit 28 receives signals from a temperature sensor 30
located along the pump discharge pathway 71. The reference 4 in the
drawings is not intended to refer to the whole pump assembly but
rather only the Device which is the control unit, sensors, and
control line.
[0028] Line 70 generally shows a flow path of the conveyed fluid 15
which enters the pump via inlets 16a, 16b. Line 71 generally shows
the path of conveyed fluid 15 exiting outlets 20a, 20b.
Additionally line 72 generally depicts the pathway of supply liquid
which enters inlets 7. The supply liquid can be operating fluid 5
and can serve as sealing fluid to seal the spaces 43.
[0029] Prior to operation, the control unit is programmed so as to
have a specified or desired process parameter Ps. During operation,
the control unit compares actual process parameter values Pi to the
specified parameters. The actual parameters are collected and
transmitted to the control unit 28 via sensors 30. The control
unit, in dependence on a comparison result transmits signals to
actuate control element 26 to discharge an amount of operating
fluid from chamber 6 to vary the actual value Pi to meet the
desired value Ps. The control element 26 of course can be a valve
directly actuated by control unit 28 or indirectly actuated by the
control unit by way of a motor. In the case of direct activation,
one could use a solenoid valve. A motor actuated valve however has
the advantage that the size of the valve aperture can be varied by
the motor to more precisely control the discharge. In general, to
increase the flow of conveyed fluid 15, an amount of operating
fluid 5 is discharged, during operation of the pump. The amount of
discharged fluid is in addition to any fluid being discharged
through outlets 20, 20b. The discharged fluid is not immediately
re-circulated back into the workspace 6. The valve can be actuated
in other ways including manually, hydraulically, or
pneumatically.
[0030] It should be noted that although device 4 uses a line 22
which branches off from total drain line 2a at the drive end, it is
contemplated that by using appropriate valves and actuators one
could use a single line for both the total drain line 2a and
control line 22 (See discussion on FIG. 4, supra.). Further,
although device 4 is shown as regulating discharge out of total
drain outlet 2 in connection with total drain line 2a, device 4
could regulate the discharge at the total drain connection 2 on the
non-drive end, i.e. at shield 18b. As a further alternative, the
control line 22 could include a conduit which interfaces the total
drain connections 2 at both the drive end and non drive end of the
pump with valve 26.
[0031] FIG. 3 shows an alternative way of interfacing a control
line 32 of device 4 for controlling the level of the operating
fluid 5, during operation of the pump, with existing pump
connections. In this embodiment, the control line is interfaced
with the inner shaft seal connections 3 on both the drive and
non-drive end. The internal shaft seal supply to which the control
line is interfaced is generally shown at 3a. The interface with
connections 3 could be through inlets 13. A liquid supply line or
pathway which feeds the liquid into the pump is generally shown by
line 73. The fluid could be operating fluid 5 for the liquid ring
or for the sealing of the spaces 43
[0032] Interfaced with control line or conduit 32 is control
element 26. The control element 26 is actuated in the same manner
as control element 26 in FIG. 2. In this embodiment, it is also
shown that the control unit 28 receives signals from a temperature
sensor 30 located along the pump discharge pathway 71.
[0033] In accordance with FIG. 4, the device 4 comprises a control
line 100 for discharging and feeding operating fluid 5 into the
workspace 6. The control line 100 opens into total outflow or
shutdown drain connection 2 of the workspace 6. The control line
100 has a controlling element 102, which is designed especially in
the style of a bi-directionally operable operating-fluid pump.
Depending on the activation of the controlling element 102,
operating fluid 5 can thus be either fed to or removed from the
workspace 4. The control line 100 can serve as the total drain line
after shut down. The device 4b additionally comprises control unit
28, which enables actuation of the controlling element 102 via
sensors 30.
[0034] FIG. 5 shows an additional embodiment. In contrast to the
embodiment according to FIG. 4, the device, in this case
incorporates two separate control lines namely one feed control
line 200a and one discharge control line 200b. The discharge
control line 200b opens into the peak 202 of the workspace 6. The
feed control line 200a opens into the workspace at the total
outflow 2. The control line 200b is preferably is interfaced with
the inner shaft seal connection 3. The interface could be through
inlets 13
[0035] The feed control line 200a and the discharge control line
200b each have a controlling element 206a and 206b in the form of a
control valve or pump for regulating the flow of the operating
fluid through control lines 200a, 200b. Control unit 28 enables
activation of controlling elements 206a, 206b depending on the
input from the sensor(s) 30.
[0036] In accordance with FIG. 6, the device, in contrast to the
embodiment according to FIG. 5, comprises only the single control
line 300 for discharging operating fluid 5. Controlling element 26
is interfaced with control line 300. The control line 300 could
have its own unique connection or interface with the inner shaft
seal connections. 3
* * * * *