U.S. patent number 3,840,185 [Application Number 05/292,334] was granted by the patent office on 1974-10-08 for liquid ejection nozzle structure.
This patent grant is currently assigned to W. C. Heraeus GmbH. Invention is credited to Rolf Ruthardt.
United States Patent |
3,840,185 |
Ruthardt |
October 8, 1974 |
LIQUID EJECTION NOZZLE STRUCTURE
Abstract
To provide for laminar flow of liquid ejected through a nozzle
structure, the surface in the region of the edge zone of the
ejection duct of the nozzle is covered with a layer of crystal
columns of at least 2 .mu.m such that the axes of the crystal
columns are essentially parallel to the axis of the ejection duct
of the nozzle in the terminal region of the nozzle, the crystal
columns, in a plane transverse to the axis of the nozzle,
exhibiting a fine crystalline structure; the crystals are
preferably made with at least one of the metals of titanium,
vanadium, niobium, tantalum, chromium, molybenum, tungsten, iron,
cobalt, nickle, gold, silver, copper, aluminum and platinum-type
metals.
Inventors: |
Ruthardt; Rolf (Hanau,
DT) |
Assignee: |
W. C. Heraeus GmbH (Hanau,
DT)
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Family
ID: |
5821015 |
Appl.
No.: |
05/292,334 |
Filed: |
September 26, 1972 |
Foreign Application Priority Data
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Sep 30, 1971 [DT] |
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2148772 |
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Current U.S.
Class: |
239/591;
29/890.142; 239/DIG.19 |
Current CPC
Class: |
F04F
5/46 (20130101); Y10T 29/49432 (20150115); Y10S
239/19 (20130101) |
Current International
Class: |
F04F
5/00 (20060101); F04F 5/46 (20060101); B05b
001/00 (); B21d 051/00 () |
Field of
Search: |
;29/157C
;239/DIG.19,589,591,602 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,373,520 |
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Aug 1964 |
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FR |
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450,522 |
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Apr 1935 |
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GB |
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Primary Examiner: Ward, Jr.; Robert S.
Attorney, Agent or Firm: Flynn & Frishauf
Claims
I claim:
1. Liquid ejector, or nozzle structure comprising
a base structural unit (1) having an exit plane (5), and a duct (2)
formed therethrough extending through the exit plane to provide for
ejection of liquid through the structure from the exit plane, the
axis of the duct being perpendicular to the exit plane in the
region of the terminal zone of the duct,
and a layer (6) applied to the exit plane (4) of the structural
unit (1) of the ejector and applied at least in the region of the
edge zone of the duct (2), said layer having a thickness of at
least 2 .mu.m and comprising a crystalline columnar structure in
which the axes of the crystal columns are essentially parallel to
the axis (3) of the duct (2) in the exit zone of the duct, the
crystal columns of the crystalline layer (6) exhibiting a fine
crystalline structure transverse to the exit surface (5).
2. Ejector, or nozzle according to claim 1 wherein the crystal
columns are of metal.
3. Ejector, or nozzle according to claim 1 wherein the crystal
columns comprise at least one of the metals comprising the group of
titanium, vanadium, niobium, tantalum, chromium, molybdenum,
tungsten, iron, cobalt, nickel, gold, silver, copper, aluminum and
platinum-type metals.
4. Ejector, or nozzle according to claim 3 wherein platinum metals
comprise platinum, palladium, rhodium, iridium, ruthenium,
osmium.
5. Ejector, or nozzle according to claim 1 wherein the crystal
columns comprise at least one metal selected from the group of
titanium, vanadium, niobium and chromium.
6. Ejector, or nozzle according to claim 1 wherein the thickness of
the crystalline columnar layer is between 2 to 20 .mu.m.
7. Ejector, or nozzle according to claim 1 wherein the structure
(1) through which the duct is formed and on which the crystal
columnar layer (6) is applied comprises a metal including at least
one of the metals of steel, beonze, brass, hard metal, titanium,
titanium alloy, zirconium, zirconium alloy, tantalum, tantalum
alloy, molybdenum, molybdenum alloy, tungsten and tungsten
alloy.
8. Method of making a liquid ejector, or nozzle structure
comprising
forming a duct (2) transverse to the thickness of a base material
(1), the terminal end of the duct extending along an axis (3)
transverse to the surface (5) of the structure to form an exit
plane (4);
and coating said exit surface (5) with a crystalline structure of a
metal comprising at least one of the metals of the group of
titanium, vanadium, niobium, tantalum, chromium, molybdenum,
tungsten, iron, cobalt, nickel, gold, silver, copper, aluminum and
platinum-type metals, by precipitating at least one of said metals
on said exit surface (5) under a pressure of less than
10.sup..sup.-1 mm Hg.
9. Method according to claim 8 including the step of maintaining
the base structure (1) through which the duct (2) is formed, at
least in the region of the exit plane (5) at an elevated
temperature in the order of about 150.degree. C, or higher.
10. Method according to claim 8 wherein the metal is evaporated on
the base structure at a pressure of less than 10.sup..sup.-4 mm Hg.
Description
The present invention relates to a liquid ejector, or nozzle
structure for liquid under pressure.
Liquid ejectors or nozzles in which liquid is ejected under
pressure from a duct, or nozzle structure is used in many
technological fields. It is frequently desired that the liquid is
ejected from the nozzle in laminar flow. Such ejection thus,
however, in many instances lead to difficulties if the liquid wets
the exit zone or surface of the nozzle structure or ejector, which
tends to deviate the liquid from the predetermined direction of the
nozzle axis. Such a case arises particularly if the exit edge of
the exit duct or nozzle structure is not perfectly symmetrical, or
geometrically exactly as designed, resulting in interference with
the flow of the liquid through the nozzle. It is particularly
important to maintain the accuracy and stability of the geometrical
shape of the exit edge of the nozzle duct, and to prevent wetting
of the edge zone of the exit surface of the ejector or nozzle by
the liquid being ejected.
It has previously been proposed to decrease the tendency to wet the
exit surface of nozzles by coating at least the edge zone of the
exit surface of the nozzle with polytetrafluorethylene.
Polytetrafluorethylene has, however, low resistance against creep
and the stability of the geometric shape of the exit edge of the
nozzle duct is insured only for a relatively short period of
time.
It is an object of the present invention to provide a liquid
ejector in which the exit zone of the nozzle or injector structure
is so constructed that unstable conditions of the geometry or shape
of the exit edge of the nozzle duct are avoided.
SUBJECT MATTER OF THE PRESENT INVENTION
It has been found, surprisingly, that by coating the exit surface
of the nozzle structure in the region of the exit zone of the
nozzle with crystalline columns of at least 2 .mu.m thickness, so
that the axes of the crystalline columns extend in general parallel
to the axis of the exit duct, such instabilities and deviation from
design of the nozzle structure, are avoided. The crystal column
structure, in a plane transverse to the axis of the nozzle duct, at
the exit edge, has a fine crystalline structure. It is particularly
desirable that the crystalline columnar layer is made of a metal,
and metals which are particularly suitable for the columnar layer
are titanium, vanadium, niobium, tantalum, chromium, molybdenum,
tungsten, iron, cobalt, nickel, gold, silver, copper, aluminum and
platinum-type metals; under platinum metals, the following are to
be understood: platinum, palladium, rhodium, iridium, ruthenium,
osmium. The results are particularly good when the crystalline
columns are made of titanium, vanadium, niobium or chromium.
It is believed that the effect of the crystalline columnar layer,
in accordance with the present invention, and the stability of the
geometry of this layer is derived from the crystalline structure of
the columnar layer itself. In the flow direction, which is
essentially laminar, a coarsely crystalline, ideally single crystal
structure is present, extending parallel to the laminar flow of the
liquid, that is, to the axis of the nozzle. In a plane
perpendicular to the flow direction, the crystalline columnar layer
has a fine crystalline structure. Thus, on the one hand,
interference of laminar flow in the flow direction by change of
grain boundaries are avoided; on the other hand, the liquid cannot
spread in the edge zone of the plane exit surface of the ejector,
that is, perpendicular to the flow direction, and thus wetting of
the edge zone by accumulation of changes in grain limits are
avoided due to the fine crystalline structure.
In accordance with the feature of the invention, the crystalline
columns are applied to a base, through which the ejector nozzle is
formed, which is preferably a metal such as steel, in a vacuum of
at least 10.sup..sup.-1 mm Hg, preferably less than 10.sup..sup.-4
mm Hg, by precipitation, preferably evaporation on the surface. In
a preferred form of the process, the liquid ejector structure is
maintained at an elevated temperature, for example in the order of
150.degree. C, depending on the metal which is being evaporated on
the nozzle surface.
The invention will be described by way of example with reference to
the accompanying drawing, wherein the single FIGURE illustrates a
schematic cross sectional view of a liquid ejector made in
accordance with the present invention.
The liquid ejector 1 is made of a base metal plate, for example
steel, and is formed with an extrusion or ejection duct 2. The
terminal zone of duct 2 extends along an axis 3, transverse to the
exit surface 4. Duct 2 has a liquid applied therethrough, under
pressure, to provide for essentially laminar flow of the liquid
from the duct 2. The exit surface 5 of the nozzle structure 1 is
coated, at least in the region of the terminal zone surrounding the
exit plane 4 by means of a crystalline columnar layer 6. The axes
of the crystalline columns extend in general parallel to axis 3 of
the exit duct, at least in the region of the terminal zone. The
crystalline columnar layer 6 exhibit a fine crystalline structure
in a plane parallel to the exit plane 5.
The length of the crystal columns, that is, the thickness of the
crystalline layer 6 is in excess of 2 .mu.m, preferably in excess
of 6 .mu.m; the thickness is determined by designed considerations
and by the process of application and may extend to 20 .mu.m or
more, but may be less for various applications, for example may be
between 6-12 .mu.m.
The base plate may be of metal other than steel, such as bronze,
brass, hard metal, titanium, titanium alloy, zirconium, zirconium
alloy, tantalum, tantalum alloy, molybdenum, molybdenum alloy,
tungsten and tungsten alloy.
* * * * *