U.S. patent application number 12/737407 was filed with the patent office on 2011-05-12 for water jet type pump and method for operation thereof.
This patent application is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Vladimir Danov, Bernd Gromoll.
Application Number | 20110110796 12/737407 |
Document ID | / |
Family ID | 40765493 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110110796 |
Kind Code |
A1 |
Danov; Vladimir ; et
al. |
May 12, 2011 |
WATER JET TYPE PUMP AND METHOD FOR OPERATION THEREOF
Abstract
A water jet type pump is part of a system for generating an
ultrahigh vacuum. The pump includes a pump chamber through which an
ionic fluid flows at high velocity. The chamber has a first fluid
feed for the fluid, the first feed ending in a nozzle with a nozzle
opening, and a fluid discharge. A second feed of the pump chamber
is connected to a high pressure chamber to be evacuated. Gas is
suctioned out of the high vacuum chamber through the second feed by
way of the flowing fluid jet, which is used to discharge the gas
out of the pump chamber.
Inventors: |
Danov; Vladimir; (Erlangen,
DE) ; Gromoll; Bernd; (Baiersdorf, DE) |
Assignee: |
Siemens Aktiengesellschaft
Munich
DE
|
Family ID: |
40765493 |
Appl. No.: |
12/737407 |
Filed: |
April 9, 2009 |
PCT Filed: |
April 9, 2009 |
PCT NO: |
PCT/EP2009/054320 |
371 Date: |
January 11, 2011 |
Current U.S.
Class: |
417/55 ;
417/87 |
Current CPC
Class: |
F04F 5/54 20130101; F04F
5/04 20130101 |
Class at
Publication: |
417/55 ;
417/87 |
International
Class: |
F04F 9/08 20060101
F04F009/08; F04B 23/08 20060101 F04B023/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2008 |
DE |
10 2008 032 825.1 |
Claims
1-13. (canceled)
14. A water-jet pump to create a high vacuum, comprising: an ionic
fluid circulation fluid, the ionic fluid circulation fluid
containing at least one of sulfate ions, hydrogen sulfate ions,
alkyl sulfate ions, thiocyanate ions, phosphate ions, borate ions,
tetrakis hydrogen sulfate oborate ions, and silicate ions; a
chamber to communicate a through-flow of the circulation fluid; a
first feed to supply the circulation fluid to the chamber, the
first feed projecting into the chamber and terminating in a nozzle
orifice, the nozzle orifice having at least a tenfold reduction in
diameter relative to an upstream portion of the first feed; an
outlet for the circulation fluid from the chamber, the outlet being
positioned opposite to the nozzle orifice, in a flow direction; a
second feed, which leads into the chamber and is connected to a
space which is to be evacuated; a feed pump to deliver the
circulation fluid into the first feed at a pre-specified velocity
and/or at a pre-specified pressure; a storage tank with a check
valve to discharge gases; and a closed fluid circuit to connect the
feed pump to the first feed, to connect the outlet to the storage
tank and to connect the storage tank to the feed pump.
15. A water-jet pump to create a high vacuum, comprising: a chamber
to communicate a fluid through-flow; a first feed to supply the
fluid, which first feed projects into the chamber and terminates in
a nozzle orifice; an outlet for the fluid from the chamber, the
outlet being positioned opposite to the nozzle orifice, in a flow
direction; and a second feed, which leads into the chamber and is
connectable to a space which is to be evacuated, wherein the fluid
is an ionic fluid.
16. The pump as claimed in claim 15, further comprising means for
delivering the ionic fluid into the first feed at a pre-specified
velocity and/or at a pre-specified pressure.
17. The pump as claimed in claim 15, further comprising a feed pump
to deliver the ionic fluid into the first feed at a pre-specified
velocity and/or at a pre-specified pressure.
18. The pump as claimed in claim 17, further comprising: a storage
tank with a check valve to discharge gases; and a closed fluid
circuit to connect the feed pump to the first feed, to connect the
outlet to the storage tank and to connect the storage tank to the
feed pump.
19. The pump as claimed in claim 15, wherein the ionic fluid is a
liquid or a liquid-gas mixture.
20. The pump as claimed in claim 19, wherein the pump creates a
vacuum pressure reduction in the space to be evacuated, and the
pressure reduction depends upon the vapor pressure of the ionic
liquid.
21. The pump as claimed in claim 15, wherein the ionic fluid
contains at least one of sulfate ions, hydrogen sulfate ions, alkyl
sulfate ions, thiocyanate ions, phosphate ions, borate ions,
tetrakis hydrogen sulfate oborate ions, and silicate ions.
22. The pump as claimed in claim 15, wherein the space to be
evacuated is an ultra-high vacuum chamber, and gas is exchanged
between the pump and the ultra-high vacuum chamber via the second
feed.
23. The pump as claimed in claim 22, wherein the pump created a
vacuum pressure reduction in the space to be evacuated, and the
vacuum pressure reduction reduces the pressure to a pressure range
of 10.sup.-7 to 10.sup.-12 mbar.
24. The pump as claimed in claim 15, wherein piping is used to form
at least one of the first feed, the second feed and the fluid
outlet.
25. A method for evacuating a space, comprising: providing a pump
comprising: a chamber to communicate a ionic fluid through-flow; a
first feed to supply the ionic fluid, which first feed projects
into the chamber and terminates in a nozzle orifice; an outlet for
the ionic fluid from the chamber, the outlet being positioned
opposite to the nozzle orifice, in a flow direction; and a second
feed, which leads into the chamber and is connectable to a space
which is to be evacuated; creating a jet of ionic fluid through the
chamber of the pump; drawing gas into the chamber with the jet of
ionic fluid; and discharging the gas from the chamber with the jet
of ionic fluid.
26. The method as claimed in claim 25, wherein creating a jet,
drawing gas, and discharging the gas are carried out in sequence,
are carried out continuously at the same time, or are carried out
in pulses.
27. The method as claimed in claim 25, wherein the jet of ionic
fluid is created using the Venturi effect.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and hereby claims priority to
International Application No. PCT/EP2009/054320 filed on Apr. 9,
2009 and German Application No. 10 2008 032 825.1 filed on Jul. 11,
2008, the contents of which are hereby incorporated by
reference.
BACKGROUND
[0002] The present invention relates to a pump in the style of a
water-jet pump for creating a high vacuum.
[0003] For creating an ultra-high vacuum, turbomolecular pumps,
cryopumps, sorption pumps, rotary plunger pumps, positive
displacement pumps and jet pumps are used. As jet pumps, water-jet
pumps or pumps based on oils as liquid are used. Only vacuum
pressures which lie within the range of the vapor pressure of the
liquid which is used can be achieved by these pumps. Therefore,
known water-jet pumps and oil pumps can be used only as fore-pumps
for creating a fore-vacuum, and for creating especially ultra-high
vacuums have to be supplemented by downstream pumps such as
turbo-molecular pumps. The pump systems which are constructed in
this way are complex, expensive and labor-intensive in
maintenance.
SUMMARY
[0004] It is one potential object to disclose a simply constructed
pump with which vacuums into the ultra-high vacuum range are to be
created. In particular, it is a potential object to disclose a pump
with as few parts as possible, above all with few or no movable
parts in order to be able to operate the pump in a wear-free and
cost-effective manner, and with a simple way to create an
ultra-high vacuum which is as beneficial as possible. In addition,
a simple method for operating such a pump is to be disclosed.
[0005] The inventors propose a pump for creating a high vacuum,
especially for creating an ultra-high vacuum, is to be constructed
in the style of a water-jet pump or of a corresponding type. For
this purpose, it comprises at least one chamber which is exposable
to throughflow by a fluid in one flow direction. This chamber has
at least one first feed for the fluid, which projects into the
chamber and terminates in a nozzle orifice. In addition, the
chamber has at least one outlet for the fluid, which is arranged
opposite the nozzle orifice, as seen in the flow direction.
Furthermore, the chamber has at least one second feed which leads
into the chamber and is to be connected to a space which is to be
evacuated. An ionic fluid is used as the fluid for such a pump.
[0006] In a preferred embodiment of the pump, provision is made for
delivering the ionic fluid at a prespecified velocity and/or a
prespecified pressure to the first feed, which preferably uses at
least one feed pump.
[0007] The pump can preferably be connected to a closed fluid
circuit or integrated into this, which comprises the feed pump for
creating a fluid pressure in the at least one first fluid feed and
which comprises a storage tank with a check valve for discharging
gases, which storage tank is connected to the at least one fluid
outlet and to the feed pump.
[0008] The ionic fluid which is to be provided for the pump may be
a liquid and/or also a liquid-gas mixture. If applicable, a
corresponding gas can also be used as fluid.
[0009] In this case, it is advantageous that with the pump the
pressure in the space which is to be evacuated can be adjusted in
dependence upon the ionic liquid which is used, especially upon the
vapor pressure of the ionic liquid.
[0010] As ionic fluid, a fluid which contains sulfate ions,
hydrogen sulfate ions, alkyl sulfate ions, thiocyanate ions,
phosphate ions, borate ions, tetrakis hydrogen sulfate oborate
ions, or silicate ions, is preferably selected.
[0011] Furthermore, the at least one second feed is preferably
connected to an ultra-high vacuum chamber for an exchange or
removal of gas between the ultra-high vacuum chamber and the at
least one feed. As a result of the exchange of gas, an ultra-high
vacuum, which lies within the pressure range of 10.sup.-7 to
10.sup.-12 mbar, can be created in the ultra-high vacuum
chamber.
[0012] In one preferred embodiment, the pressure in the ultra-high
vacuum chamber is dependent upon the ionic liquid which is used,
especially upon the vapor pressure of the ionic liquid.
[0013] In a further preferred embodiment, the at least one first
fluid feed and/or the at least one second feed and/or the at least
one fluid outlet are, or is, designed in the form of at least one
pipe in each case.
[0014] The inventors also propose a method for operating the pump,
which involves:
Creating a jet of fluid which flows through the chamber of the
pump, drawing in gas in and/or into the chamber by the fluid jet,
and discharging the gas from the chamber by the fluid jet. The
steps in this case can be carried out in the stated sequence
continuously at the same time or one after the other in pulses.
[0015] In a preferred embodiment of the operating method, the
so-called Venturi effect is utilized by a corresponding design of
the pump. In this way, high flow velocities of the fluid in the
chamber and therefore particularly high negative pressures at the
second feed are to be achieved which can lead to corresponding high
vacuums into the range of ultra-high vacuums in a connected space
which is to be evacuated.
[0016] The proposals aregenerally based on the idea that by the use
of ionic fluids such as liquids in the specially designed jet
pumps, a beneficial ultra-high vacuum can be created in a simple,
reliable, low-wear and therefore inexpensive manner as a result of
the low vapor pressure of such fluids, without the necessity of a
large number of pump systems.
[0017] The previously mentioned advantages which are associated
with the pump ensue for the operating method.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] These and other objects and advantages of the present
invention will become more apparent and more readily appreciated
from the following description of the preferred embodiments, taken
in conjunction with the accompanying drawings of which:
[0019] FIG. 1 shows in a greatly schematized view a construction
for creating an ultra-high vacuum with a jet pump.
[0020] FIG. 2 shows a detail of the chamber of the pump.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to like elements throughout.
[0022] In FIG. 1, the construction of a system 1 for creating
especially an ultra-high vacuum HV is shown. The system 1 comprises
a pump 2 with a first fluid feed 3 and a second feed 4 and also a
fluid outlet 5. The pump 2 is integrated into a closed fluid
circuit 9 which uses an ionic liquid as fluid F. The pump functions
in the manner of a water-jet pump, wherein its operating medium,
however, is not water but an ionic liquid or a corresponding
liquid-gas mixture.
[0023] In the fluid circuit 9, the flow direction of the fluid F is
identified by s. With regard to the flow direction, a feed pump 6
is connected upstream to the pump 2 and creates a high fluid
pressure in at least one pipe-like section 9a of the fluid circuit
9 upstream of the pump 2. Fluid F at a high flow velocity and/or at
a high internal fluid pressure is therefore pumped by the feed pump
6 to the pump 2 via the section 9a of a pipe system. The fluid F
enters a chamber 11 of the pump 2 there via the first fluid feed 3.
For this, the feed projects a little into the chamber and is
designed there as a nozzle with a nozzle orifice 3a (cf. FIG. 2).
The fluid is sharply accelerated in the process. The acceleration
is brought about according to the so-called Venturi effect on
account of a corresponding design of the nozzle. The fluid flow
velocity is increased for example tenfold to a hundred fold or
thousand fold. Fluid flow velocities up to sonic speed are
possible. The flow velocity is dependent upon the fluid pressure
directly in front of the nozzle and upon the nozzle diameter in
proportion to the piping diameter of the first fluid feed 3. The
fluid jet, which discharges at high velocity from the nozzle at its
orifice 3a, absorbs portions of the gas which is in the chamber 11,
for example as a result of impacts with the gas molecules and
vortices as a result of friction in the gas in the chamber. The gas
molecules which are entrained with the fluid flow discharge from
the chamber 11 together with the fluid F at the fluid outlet 5
which lies opposite the nozzle orifice 3a.
[0024] Via a section 9b of the piping system, the fluid F which
discharges from the chamber 11 via the fluid outlet 5 is directed
into a storage tank 7. The fluid F is collected there and entrained
gas molecules can escape from the fluid and, via a check valve 8,
be discharged to the environment or into a further collecting tank.
The collected fluid from the storage tank 7 can then be fed to the
feed pump 6 by a further section 9c of the piping system, with
which a completed fluid circuit 9 in the piping system results.
[0025] In the chamber 11 of the pump 2, the gas molecules which are
entrained and transported away with the fluid F lead to a negative
pressure at a second feed 4 of the chamber 11 of the pump 2. A
high-vacuum chamber 10 is connected to the second feed 4 of the
pump chamber 11 via a piping system 12, for example a stainless
steel pipe. Thus, an exchange or transporting of gas can take place
between the high-vacuum chamber 10 and the pump chamber 11. The
negative pressure which is created in the pump chamber 11 leads to
a flow of gas, which gas can flow from a higher gas pressure in the
high-vacuum chamber 10 to a lower gas pressure in the pump chamber
11. Only when a pressure balance has taken place, i.e. when the
same gas pressure exists in the high-vacuum chamber 10 and in the
pump chamber 11, does exchange of gas between the ultra-high vacuum
chamber 10 and the pump chamber 11 no longer take place. The
exchange of gas between the high-vacuum chamber 10 and the pump
chamber 11 can therefore lead to a pressure drop in the high-vacuum
chamber 10, i.e. gas is thus to be pumped out of the high-vacuum
chamber 10 into the pump chamber 11.
[0026] With the described method, a gas pressure or a vacuum with a
pressure which corresponds at least approximately to the vapor
pressure of the fluid F which is used, can be created in the
high-vacuum chamber 10. By using an ionic fluid as the operating
medium of the pump 2, high-vacuum gas pressures can be achieved,
i.e. a high vacuum in a high-vacuum chamber 10 which reaches into
the ultra-high vacuum range of 10.sup.-7 to 10.sup.-12 mbar.
[0027] Ionic fluids which are suited to the pump are known for
example from "Angewandte Chemie" (Applied Chemistry), 2000, Volume
112, pages 3926 to 3945. According to this, liquids which at low
temperatures, particularly at temperatures below 100.degree. C.,
are melting salts with non-molecular, ionic character, are
generally considered as such fluids. An especially advantageous
property of such ionic liquids for use in the pump is that these
have a practically non-measurable vapor pressure (at the usual
application temperatures). Therefore, in spaces which are to be
evacuated, negative pressures, which correspond to the vapor
pressure of the liquids which are to be used, can be achieved.
During operation of the pump, practically no liquid evaporates so
that the drawn-in gas is easy to separate from the liquid.
[0028] Particularly suitable are fluids F (liquid or in a two-phase
liquid-gas mixture) which contain sulfate ions, hydrogen sulfate
ions, alkyl sulfate ions, thiocyanate ions, phosphate ions, borate
ions, tetrakis hydrogen sulfate oborate ions, or silicate ions, at
least as the chief portion (i.e. more than 50% by volume).
[0029] The invention has been described in detail with particular
reference to preferred embodiments thereof and examples, but it
will be understood that variations and modifications can be
effected within the spirit and scope of the invention covered by
the claims which may include the phrase "at least one of A, B and
C" as an alternative expression that means one or more of A, B and
C may be used, contrary to the holding in Superguide v. DIRECTV, 69
USPQ2d 1865 (Fed. Cir. 2004).
* * * * *