U.S. patent application number 16/327586 was filed with the patent office on 2019-07-18 for production of a porous aluminum filter for a diaphragm pump.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. The applicant listed for this patent is SIEMENS AKTIENGESELLSCHAFT. Invention is credited to Frank HANNEMANN, Sebastian RAHM, Marcus WEDER.
Application Number | 20190217233 16/327586 |
Document ID | / |
Family ID | 59772595 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190217233 |
Kind Code |
A1 |
HANNEMANN; Frank ; et
al. |
July 18, 2019 |
PRODUCTION OF A POROUS ALUMINUM FILTER FOR A DIAPHRAGM PUMP
Abstract
A method produces a porous, arched aluminum fluidization element
for a diaphragm pump for fluidizing, covering and delivering
pulverized products, such as pulverized coal, using inert gas at
pressures of up to 7 MPa. The fluidization element ensures that
fluidizing gas is supplied and homogeneously distributed in the
pump lower region, and the contour of the space for pulverized
materials may be advantageously designed in the diaphragm
deflection area and optionally adapted to the diaphragm guide rod.
In this way, a homogeneous and reversible deformation of the
diaphragm is obtained with minor wear as far as possible. At the
end of the delivery process of the diaphragm pump, the diaphragm is
applied to the arched, half-shell-shaped fluidization surface in an
extensively flat manner, and a small dead volume can be obtained,
which results in minimal space for pulverized materials with a high
delivery rate and little high-pressure gas loss.
Inventors: |
HANNEMANN; Frank;
(Roettenbach, DE) ; RAHM; Sebastian; (Dresden,
DE) ; WEDER; Marcus; (Bannewitz OT Haenichen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SIEMENS AKTIENGESELLSCHAFT |
Muenchen |
|
DE |
|
|
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
Muenchen
DE
|
Family ID: |
59772595 |
Appl. No.: |
16/327586 |
Filed: |
August 22, 2017 |
PCT Filed: |
August 22, 2017 |
PCT NO: |
PCT/EP2017/071073 |
371 Date: |
March 5, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D 2239/10 20130101;
F04B 43/02 20130101; F04B 53/22 20130101; F04B 43/06 20130101; B01D
2239/1216 20130101; B01D 39/2051 20130101 |
International
Class: |
B01D 39/20 20060101
B01D039/20 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 25, 2016 |
DE |
10 2016 216 016.8 |
Claims
1. A method for producing a gas-permeable body which is formed with
aluminum, in which method salt is admixed to an aluminum melt, the
mixture composed of aluminum melt and salt is allowed to solidify,
the solidified mixture is processed into the desired body form, and
the salt is removed from the body form by means of a dissolution
process.
2. The method for producing a gas-permeable body as claimed in
claim 1, wherein the desired porosity and filter fineness is set by
means of the size of the salt grains.
3. A gas-permeable body composed of aluminum, which is produced by
means of the following sequence of working steps: admixing salt to
an aluminum melt, solidifying the mixture composed of aluminum melt
and salt, processing the solidified mixture into the desired body
form, and removing the salt from the body form by means of a
dissolution process.
4. The gas-permeable body as claimed in claim 3, wherein a porous
metallic filter material is formed.
5. The gas-permeable body as claimed in claim 4, wherein the
fineness of the filter material amounts to <40 .mu.m.
6. The gas-permeable body as claimed in claim 4, wherein the
fineness of the filter material amounts to <20 .mu.m.
7. The gas-permeable body as claimed in claim 3, wherein the
gas-permeable body is connected to a gas-impermeable body so as to
form a unit.
8. The gas-permeable body as claimed in claim 3, wherein the
gas-permeable body is part of a gas-impermeable aluminum body.
9. The gas-permeable body as claimed in claim 3, wherein the body
form is adapted to the deflected form of a diaphragm of a dust
pump.
10. The gas-permeable body as claimed in claim 3, wherein a dust
feed pipe (7) is connected at the lowest point.
11. The gas-permeable body as claimed in claim 3, wherein at least
one support (8) is formed integrally.
Description
[0001] The invention relates to a method for producing a
gas-permeable body which is formed with aluminum, and to a
gas-permeable aluminum body produced in accordance with said
method.
[0002] A body produced in accordance with the method according to
the invention can be advantageously used as a loosening surface in
a diaphragm pump for the fluidizing and charging of products in
dust form, such as for example coal dust, by means of inert gas at
pressures of up to 7 MPa as a filter element.
[0003] Continuous and inexpensive dense-stream conveying in the
case of fluctuating dust quality of dusts for combustion for carbon
and biomass gasification plants is of increasing importance in
order, for example, to operate gasification plants economically and
with high availability. This aim is achieved in a particular manner
using a diaphragm pump as proposed in the patent application
DE102016201182 of Jan. 27, 2016. The material for conveying in dust
form is in this case drawn into the diaphragm pump from below, is
charged and fluidized in a subsequent step, and is subsequently
conveyed out under pressure. The residual gas volume in the dust
chamber of the diaphragm pump is expanded in a final step after the
material for conveying has been conveyed out, and the pump cycle
begins again. Owing to this cyclic (discontinuous) mode of
operation, it is normally the case that multiple pump heads are
connected together in order to ensure continuous operation. For
this purpose, the individual pump cycles are implemented with a
phase offset with respect to one another. Filter materials which
satisfy the requirements with regard to compressive strength and
temperature resistance are for example the metallic filtration
fabrics described in DE102012216084, sintered metal and sintered
plastic. The described robust materials are available only in a
flat or plate-like structure and not in the required size or
dimensions. Mechanical processing into other geometrical shapes,
such as for example half-shells, is not possible owing to the
required filter fineness and the damage to or clogging of the
porous filter structure that arises during mechanical
processing.
[0004] From the special print from "Industriepumpen +Kompressoren"
["Industrial pumps and compressors"], 16th volume, book 3-2010,
pages 120-123, Vulkan-Verlag Essen, with the title "Prozesspumpen
mit zustandsuberwachter redundanter Schlauchmembran-Einspannung"
["Process pumps with state-monitored redundant hose diaphragm
clamping"] by Heinz M. Nagel, a process pump is known, the double
diaphragm of which is monitored with regard to integrity by means
of coupling fluid and connection to a diaphragm rupture
indicator.
[0005] The invention is based on the object of providing a filter
element for feeding fluidizing and charging gas into the pressure
vessel of a diaphragm pump, which filter element combines the
requirements of pressure resistance, temperature resistance,
adequate filter fineness, producibility with low outlay, and
interaction with the diaphragm for the purposes of high diaphragm
availability.
[0006] The object is achieved by means of a method for producing a
gas-permeable aluminum body having the features of claim 1, and by
means of a gas-permeable aluminum body produced in accordance with
said method, having the features of claim 3.
[0007] The invention utilizes the realization that, for the mode of
operation of the diaphragm pump, a uniformly distributed feed of
the fluidizing gas in the lower region of the dust pump is
essential. In the case of the loosening element produced in
accordance with the invention, it is ensured that, by means of
processing to form a domed filter element with a 3-dimensional
shaping, any clogging of the material is avoided, and a uniform
porosity can be realized.
[0008] The loosening element produced in accordance with the
invention has a constant porosity, whereby it can be ensured that
superfine dust particles do not ingress into the loosening surface
during the expansion process of the dust chamber, giving rise to a
uniformly distributed feed of fluidizing gas into the dust chamber
during the charging process.
[0009] The invention permits a structural design of the dust
chamber with a contour which is adapted in a particularly
advantageous manner to the deflection of the diaphragm and possibly
to the guide rod of the diaphragm. In this way, a uniform and
reversible deformation of the diaphragm with the least possible
wear is achieved.
[0010] After the completion of the conveying-out process of the
diaphragm pump, it can be achieved that the diaphragm (3) lies
substantially areally against the half-shell-shaped loosening
surface (5). By means of this advantageous embodiment, a small dead
volume can be achieved, which leads to a minimal dust chamber
volume (10) with a simultaneously high conveying rate and low
losses of high-pressure gas.
[0011] In the case of a hydraulically driven diaphragm pump for the
pneumatic high-pressure conveyance of fluidized dusts, which
diaphragm pump is equipped with the filter element produced in
accordance with the invention, the pressure vessel that encloses
the dust chamber has small dimensions with a minimized wall
thickness, which leads to a reduction in production outlay.
[0012] In one particular embodiment of the invention, the loosening
surface 5 has, at the lowest point, a circular opening to which
there is fastened a dust pipe 7 through which the material for
conveying in dust form can be conveyed in and conveyed out, which
material for conveying thus cannot pass into the gas chamber
13.
[0013] Advantageous refinements of the invention are specified in
the subclaims.
[0014] The invention will be discussed in more detail below in an
exemplary embodiment, to an extent required for the purposes of
understanding, on the basis of FIG. 1.
[0015] The diaphragm pump illustrated in FIG. 1 is an apparatus
composed of two pressure-resistant half-shells (1, 12) which are
connected to one another in gas-tight fashion by means of a flange
connection (2). The flange connection has, aside from the
possibility of easy disassembly of the dust pump, the additional
function of fastening and clamping the diaphragm (3) and the
loosening surface (5) by means of a filter flange (4). By means of
the spherical geometry, it is thus possible for an advantageous
deflection, which conserves the filter material, of the diaphragm
into the dust chamber in the form of a paraboloid of revolution to
be realized. The deflection of the diaphragm is in this case caused
by an action of force of the hydraulic liquid, as described for
example in DE102016201182. Abrupt changes are avoided, and after
the completion of the conveying-out process, it can be achieved
that the diaphragm (3) lies substantially areally against the
half-shell-shaped loosening surface (5). By means of this
advantageous embodiment, a small dead volume can be achieved, which
leads to a minimal dust chamber volume (10) with a simultaneously
high conveying rate and low losses of high-pressure gas. To avoid
undesired movements and folding during the conveying-out process,
the diaphragm is guided and stabilized in terms of its movement by
means of a guide rod (9). The guide rod may, in a particularly
advantageous embodiment, perform additional tasks such as for
example the determination of the position of the diaphragm by means
of measuring position transducers.
[0016] The invention is furthermore based on the problem of
generating dense-stream conveying, described in DE 2005047583, by
generating a fluidized bed within the dust chamber. This is
achieved during the charging and conveying-out process by means of
a homogeneous feed of gas via a half-shell-shaped and gas-permeable
loosening surface (5). As filter material for the loosening surface
(5), use is made of porous metal, for example aluminum, with an
adequately small pore size and filter fineness of <20 .mu.m. It
can thus be ensured that superfine dust particles do not ingress
into the loosening surface during the expansion process.
[0017] For the production of porous metal, liquid metal, for
example aluminum, together with granulated salt is cast into a
half-shell mold. Salt has a significantly higher melting point for
example in relation to metals such as aluminum, and does not change
into the liquid state of aggregation, but rather distributes
uniformly in the melt. After solidification of the metal, the salt
is washed out by means of a salt-dissolving liquid, and porous and
gas-permeable metal is formed. An advantage of this method consists
in the possibility of performing mechanical processing prior to the
washing-out of the salt crystals. In this way, clogging of the
pores is ruled out. The required porosity and filter fineness is
set by means of the size of the salt grains.
[0018] In order to realize an advantageous flange seal (2), the
loosening surface (5) may be formed in two layers; as a porous
metal in the lower region and as a solid material in the flange
region.
[0019] In a particular embodiment of the invention, the
half-shell-shaped casting mold of the loosening surface (5) is
expanded to include additional ring-shaped and/or punctiform
support elements (8). It is thus possible for the half-shell-shaped
loosening surface (5) composed of porous metal to be fitted and
fastened into the lower pressure-resistant half-shell (12) composed
of solid material. A gas chamber 13 is advantageously formed
between the loosening surface composed of porous metal and the
pressure-resistant half-shell, which gas chamber can be used for
the distribution of the loosening and charging gas. The feed and
discharge of the loosening and charging gas is realized by openings
6 in the lower pressure-resistant half-shell 12.
[0020] In the case of a hydraulically driven diaphragm pump for
pneumatic high-pressure conveying of fluidized dusts, the reliable
sealing of the dust chamber from the hydraulic chamber, which are
separated by means of the diaphragm, is of particular importance.
The deflection of the diaphragm and the associated drawing-in and
conveying-out of the material for conveying in dust form is
achieved by virtue of the hydraulic fluid in the hydraulic chamber
situated above the diaphragm being forced in and forced out. Within
this conveying process, the ingress of dust into the hydraulic
liquid or of hydraulic liquid into the dust chamber is associated
with considerable plant malfunctions and would lead to cumbersome
repairs.
[0021] One special feature of the invention consists in the
monitoring and assurance of the diaphragm leak-tightness. For this
purpose, the diaphragm (3) is designed as a double diaphragm with
integrated pressure sensor for leakage monitoring. In this way, it
is possible for a hermetically sealed separation between hydraulic
chamber (11) and dust chamber (10) to be ensured, and damage to the
diaphragm can be identified in good time. Cumbersome repair and
cleaning measures of the entire dust system or hydraulics system in
the event of diaphragm damage are avoided, and the leak-tightness
of the diaphragm is maintained during the fault situation.
[0022] In the case of the diaphragm 3 being designed as a double
diaphragm, two resiliently elastic diaphragms are arranged so as to
be mechanically supported relative to one another such that a
closed intermediate space is formed between the diaphragms, which
intermediate space can be monitored by means of a pressure sensor
.DELTA.p (14). During fault-free operation, the intermediate space
has a pressure lower than the pressure in the hydraulics chamber or
the dust chamber. If a pressure increase is now detected in the
intermediate chamber, a leakage of one of the two diaphragms of the
double diaphragm is inferred. The two diaphragms may be arranged so
as to be mechanically supported relative to one another in
punctiform fashion by virtue of a layer of balls being arranged
between them. The two diaphragms may be arranged so as to be
mechanically supported relative to one another by virtue of a
coupling liquid being introduced between them, which coupling
liquid is operatively connected to the pressure sensor
.DELTA.p.
[0023] The resiliently elastic diaphragm may be formed with an
elastomer or a solid PTFE mixture. In the case of the double
diaphragm, one of the two diaphragms may be realized by means of an
elastomer, and the other of the two diaphragms may be realized by
means of a solid PTFE mixture.
[0024] The invention is also provided by means of a diaphragm pump
for fluidizing and conveying dusts, in the case of which [0025] the
pressure-resistant housing of the dust pump is composed of two
half-shells which are connected by means of a flange connection and
into which a diaphragm and a loosening surface are flange-mounted,
[0026] the loosening surface is formed in layers from porous
material in the lower region and solid material in the region of
the flange connection, [0027] the loosening surface is designed as
a half-shell and comprises support elements, and a gas chamber
exists between pressure-resistant lower half-shell and loosening
surface.
[0028] The present invention has been discussed in detail for
illustrative purposes on the basis of specific exemplary
embodiments. Here, elements of the individual exemplary embodiments
may also be combined with one another. The invention is therefore
intended not to be restricted to individual exemplary embodiments,
but rather restricted only by the appended claims.
LIST OF REFERENCE DESIGNATIONS
[0029] 1 Pressure-resistant upper half-shell, hydraulics half-shell
[0030] 2 Container flange [0031] 3 Diaphragm [0032] 4 Filter flange
[0033] 5 Loosening surface composed of porous metallic filter
material [0034] 6 Openings for charging and conveying gas, gas pipe
[0035] 7 Inner pipe for inlet and outlet of the dust, dust pipe
[0036] 8 Ring-shaped, punctiform, strip-shaped support elements
[0037] 9 Diaphragm guide/guide rod [0038] 10 Dust chamber [0039] 11
Hydraulics chamber [0040] 12 Pressure-resistant lower half-shell,
dust half-shell [0041] 13 Gas chamber [0042] 14 Pressure sensor
.DELTA.p
* * * * *