U.S. patent application number 09/794654 was filed with the patent office on 2001-10-25 for tube scraper.
Invention is credited to Sotirakos, Bill, Wang, Demao.
Application Number | 20010032659 09/794654 |
Document ID | / |
Family ID | 4165991 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010032659 |
Kind Code |
A1 |
Wang, Demao ; et
al. |
October 25, 2001 |
Tube scraper
Abstract
A scraper for removing deposits from the exterior of a tubular
member includes elements defining an outer jacket which has an
inwardly open circumferential recess and two aligned axial
openings, and a scraper element in the form of an elongate
resilient wire bent to define a series of integral, concatenated,
resilient segments, each pair of adjacent segments being connected
through a bend or geniculation. All geniculations are received
within the recess, and each segment of wire extends generally along
a chord of the aligned axial openings. The positions of the chords
are distributed around the circumference of the axial openings such
that, in order for the tubular member to be accommodated through
the aligned openings, the various segments must be deformed
outwardly, whereby the resilience of the thus deformed segment
urges it inwardly against the tubular member, and causes it to
clean the tubular member as the scraper moves axially.
Inventors: |
Wang, Demao; (Toronto,
CA) ; Sotirakos, Bill; (Thornhill, CA) |
Correspondence
Address: |
Todd M. Petersen
SHERIDAN ROSS P.C.
Suite 1200
1560 Broadway
Denver
CO
80202-5141
US
|
Family ID: |
4165991 |
Appl. No.: |
09/794654 |
Filed: |
February 27, 2001 |
Current U.S.
Class: |
134/6 ;
15/104.04; 15/246 |
Current CPC
Class: |
B08B 1/008 20130101;
C02F 2201/324 20130101; B08B 9/023 20130101; B21C 43/00 20130101;
C02F 1/325 20130101 |
Class at
Publication: |
134/6 ;
15/104.04; 15/246 |
International
Class: |
B08B 009/023; B08B
001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 20, 2000 |
CA |
2,306,546 |
Claims
1. For the removal of deposits from the exterior of a tubular
member, a scraper comprising: an outer jacket defining an inwardly
open circumferential recess and two aligned axial openings, a
scraper element in the form of an elongate resilient wire bent to
define a series of integral, concatenated, resilient segments, each
pair of adjacent segments being connected through a geniculation,
the geniculations being received within said recess with at least
one segment extending substantially along a chord of the aligned
axial openings, whereby, in order to accommodate the tubular member
through said aligned axial openings, the tubular member must deform
said at least one segment outwardly, so that the resilience of the
deformed segment urges it inwardly against the tubular member and
causes it to clean the tubular member as the scraper moves axially
relative to the tubular member.
2. The scraper of claim 1 in which the resilient wire is non-round
in transverse section.
3. The scraper of claim 1 in which the resilient wire has a
polygonal cross-section.
4. The scraper of claim 1 in which the resilient wire has a square
cross-section.
5. The scraper of claim 1 in which the bending of the resilient
wire is such that a given geniculation lies within the recess at a
location closely adjacent to, but not coincident with, the
locations of the geniculations which are three segments away from
the given geniculation in either direction.
6. The scraper of claim 1 in which the aligned openings are
substantially circular, and in which substantially all wire
segments extend substantially along chords of the aligned
openings.
7. The scraper of claim 1 in combination with means for supporting
the scraper in a position in which it can surround the tubular
member, and can move axially relative to the tubular member.
8. The scraper of claim 7 in which the bending of the resilient
wire is such that a given geniculation lies within the recess at a
location closely adjacent to, but not coincident with, the
locations of the geniculations which are three segments away from
the given geniculation in either direction, all geniculations being
rounded.
9. The scraper of claim 1 in which said outer jacket includes a
cylindrical outer member, a pair of annular washers adapted to fit
within said outer member in spaced-apart relation, and a pair of
circlips for holding the washers in place, the outer member having
internal circumferential grooves for receiving the circlips.
10. A method of removing deposits from the exterior of a tubular
member, the method comprising: providing a scraper which includes:
an outer jacket defining an inwardly open circumferential recess
and two aligned axial openings, and a scraper element in the form
of an elongate resilient wire bent to define a series of integral,
concatenated, resilient segments, each pair of adjacent segments
being connected through a geniculation, the geniculations being
received within said recess with at least one segment extending
substantially along a chord of the aligned axial openings, and
inserting the tubular member through said aligned openings so as to
deform said at least one segment outwardly, whereby the resilience
of the deformed segment urges it inwardly against the tubular
member and causes it to clean the tubular member as the scraper
moves axially relative to the tubular member.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to a method and apparatus
for maintaining the external surface of a tubular member free of
scale, deposits, and the like. This invention is particularly
suited to the scraping and cleaning of protective quartz tubes used
in the ultra-violet sterilisation and/or disinfection of water and
other liquids, but is not limited thereto.
BACKGROUND OF THE INVENTION
[0002] It is well known to use ultraviolet light in the
sterilisation and/or disinfection of water. In addition,
ultraviolet light may be used to effect other treatments or
reactions in fluids, including water and air. The ultraviolet light
is typically obtained from a lamp that is in the form of a straight
hollow tube of a material transparent to ultraviolet light,
especially a quartz tube. A quartz sheath may also be used.
Electrical connections extend through the sealed ends of the tubes,
and these electrical connections are protected from contact with
the fluid.
[0003] The surface of the ultraviolet lamp, or outer sheath if
used, tends to accumulate scale, deposits or the like, especially
after a period of continuous use. The problems of scale and other
deposits are partially acute in the treatment of water.
Accumulation of scale and other deposits on the surface of the tube
reduces the transmission of ultraviolet light from the lamp into
the fluid. This causes a decrease in the intensity of the light and
consequently the efficiency and effectiveness of the treatment
decreases. In the treatment of water, cleaning of the outer surface
of the tube may be required weekly, daily or even more frequently,
depending on the quality of the water being treated.
[0004] Cleaning of the tubes could be effected by removal of the
tubes from the fluid and scraping or chemical treatment. In the
typical situation of use of a plurality of tubes in a cluster, this
might require partial disassembly of the apparatus and extended
down-time in the use of the apparatus.
[0005] Various methods have been developed for cleaning of tubes
without removal of the tubes from the fluid, using brushes, wipers
or the like. One such system is disclosed in U.S. Pat. No.
5,266,280, issued Nov. 30, 1993 to Hallett. In this system, a
cylindrical UV-transparent sheath is utilized to isolate a UV lamp
from the interior space of a reactor vessel. The sheath is sealed
in such a way as to isolate the UV lamp from the fluid. A brush
device is provided for brushing the exterior surface of the sheath
to remove materials deposited from the fluid. The brush device has
at least two brushes with bristles extending radially inwardly
towards the sheath as the brushes encompass the sheath. The brushes
are coupled together in spaced-apart manner on the sheath with a
device for reciprocating the brushes along the exterior of the
sheath, preferably on a periodic basis.
[0006] U.S. Pat. No. 3,462,597, issued on Aug. 19, 1969 to Young,
discloses a UV lamp system for water purification that includes a
wiper system for the protective sheath surrounding the UV lamp. The
wiper system comprises wiper rings made from Teflon.TM. or like
material not affected by UV radiation. The rings are spaced apart
from one another and are preferably split so that they can be
elastically or resiliently held on the outside of the protective
tube by a spring. The wiping ring is connected to a ring holder
which is engaged by a rod that extends through an end of the
reactor. The ring holder is then reciprocated to provide a wiping
action along the protective tube to remove physical or biological
materials that have deposited on the outside of the tube. However,
the system would seem to be inadequate to accommodate dimensional
variations in the protective tube, which is normally made of
quartz. Further, use of wiper rings made of Teflon.TM.
fluoropolymer or similar material would not clean the quartz
surface due to a) the lack of a sharp, hard scraping surface (such
as a razor) and b) the inherent slipperiness of Teflon
fluoropolymer.
[0007] U.S. Pat. No. 3,562,520, issued on February, 1971 to Hippen,
discloses the use of a wiper system to routinely clean a protective
quartz tube surrounding a UV lamp. The wiper system includes a
number of ring-like wiper elements surrounding and in wiping
contact with the external surface of the protective tube. The wiper
assembly is urged along the tube by a coil spring. When water to be
treated flows through the reactor, the wiper returns to the other
end of the tube to effect a wiping of the area of the tube between
the inlet and outlet. This is said to ensure that the protective
tube is free of deposits during each start-up of the water
purifying device.
[0008] U.S. Pat. No. 3,904,363, issued on Sep. 9, 1975 to Free,
discloses a wiper system that is also activated by water flow.
However, for extended continuous water flow, the protective tube
would not be cleaned. Water flow moves the wiper system to one end
of the tube and keeps it there. When the water shuts off, the
wipers descend to the base of the reactor under the influence of
gravity. The wiper system includes a flexible semi-rigid plastic or
flexible metal membrane. The membrane may be a brush-like textured
membrane of composite or plastic material. However, the membrane is
very thin and is likely to be inadequate to remove stubborn
deposits on the protective sheath. Also, the plastic version of the
wiper would be subject to deterioration under a high intensity UV
radiation from high powered lamps.
[0009] The inability of the devices disclosed in U.S. Pat. Nos.
3,562,520 and 3,904,363 to operate with a continuous flow of water
would mean that an extended water flow through the device would
result in the gradual build-up of deposits on the protective tube.
This would reduce the transmittal of UV light, and consequently the
effectiveness of the UV radiation in treating bacteria.
[0010] U.S. Pat. No. 5,528,044, issued on Jun. 18, 1996 to
Hutchinson discloses use of a wiper assembly having a rod that can
be moved from outside the reactor chamber to mechanically
reciprocate the wiper assembly. The wiper assembly has a plate with
a plurality of radial inwardly extending finger members that engage
the outer surface of the tube surrounding the lamp.
[0011] Additional patents are U.S. Pat. Nos. 4,482,809, 4,872,980,
5,006,244 and 5,418,370, all issued to Maarschalkerweerd. In the
devices described in first three of these patents, the sleeve
surrounding the UV lamps becomes periodically fouled with foreign
materials, and then requires manual cleaning to remove such
materials. The latter patent overcomes this disadvantage by
providing a cleaning apparatus which incorporates a cleaning sleeve
engaging a portion of the exterior of the radiation source assembly
and moveable between a retracted position and an extended position.
The cleaning sleeve includes the chamber in contact with part of
the radiation source, which chamber is supplied with a cleaning
solution suitable to remove undesired materials. Such a method and
apparatus for cleaning tends to be relatively complicated and
expensive.
[0012] A simple and effective method and apparatus for cleaning the
exterior surfaces of tubes would be beneficial.
SUMMARY OF THE INVENTION
[0013] In view of the disadvantages of the prior art enumerated
above, it is an object of one aspect of this invention to provide a
scraper for removing deposits from the exterior of a tubular member
such as a protective quartz sheath.
[0014] Accordingly, one aspect of the present invention provides,
for the removal of deposits from the exterior of a tubular member,
a scraper comprising:
[0015] an outer jacket defining an inwardly open circumferential
recess and two aligned axial openings,
[0016] a scraper element in the form of an elongate resilient wire
bent to define a series of integral, concatenated, resilient
segments, each pair of adjacent segments being connected through a
geniculation,
[0017] the geniculations being received within said recess with at
least one segment extending substantially along a chord of the
aligned axial openings,
[0018] whereby, in order to accommodate the tubular member through
said aligned axial openings, the tubular member must deform said at
least one segment outwardly, so that the resilience of the deformed
segment urges it inwardly against the tubular member and causes it
to clean the tubular member as the scraper moves axially relative
to the tubular member.
[0019] A further aspect of the present invention provides a method
of removing deposits from the exterior of a tubular member, the
method comprising:
[0020] providing a scraper which includes:
[0021] an outer jacket defining an inwardly open circumferential
recess and two aligned axial openings,
[0022] and a scraper element in the form of an elongate resilient
wire bent to define a series of integral, concatenated, resilient
segments, each pair of adjacent segments being connected through a
geniculation,
[0023] the geniculations being received within said recess with at
least one segment extending substantially along a chord of the
aligned axial openings,
[0024] and inserting the tubular member through said aligned
openings so as to deform said at least one segment outwardly,
whereby the resilience of the deformed segment urges it inwardly
against the tubular member and causes it to clean the tubular
member as the scraper moves axially relative to the tubular
member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Two embodiments of this invention are illustrated in the
accompanying drawings, in which like numerals denote like parts
throughout the several views, and in which:
[0026] FIG. 1 is an exploded, perspective view of the main
components of one embodiment of this invention;
[0027] FIG. 2 is an axial sectional view of the primary components
seen in FIG. 1, also in exploded relation;
[0028] FIG. 3 is an end elevation of the assembled scraper of which
the parts are shown in FIGS. 1 and 2, illustrating the theoretical
positioning of one segment of a scraper element (made of bent
wire), to illustrate the principle of the invention;
[0029] FIG. 4 is a view similar to FIG. 3, showing a tubular member
in transverse section passing through aligned openings of a jacket
member, with the tubular member bending the scraper segment out of
position, thus creating inward pressure, allowing the wire segment
to clean a portion of the surface of the tubular member;
[0030] FIG. 5 is an axial view of the scraper, showing a number of
wire segments;
[0031] FIG. 6 is an axial sectional view of a portion of the main
holding element of the second embodiment, which is similar to the
same element in FIG. 2; and
[0032] FIG. 7 is a schematic side elevation showing a tubular
member, a scraper member, and means for moving the scraper member
along the tubular member.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The present invention provides a scraper for removing
deposits from the exterior of a tubular member, such as a tubular
quartz sheath. In particular embodiments, the scraper provides a
scraper element for contacting the tubular member. Such a scraper
element may take the form of an elongate resilient wire held within
an outer jacket so as to present segments of the wire extending
along chords of aligned axial openings. In this manner, the tubular
member can be accommodated through the openings only by deforming
the wire segments outwardly. The resilience of the segments urges
them against the tubular member and longitudinal movement of the
scraper, resulting in cleaning of the surface of the tubular
member.
[0034] Attention is first directed to FIG. 1, which illustrates the
four basic elements of the scraper 9 described herein. The four
elements are seen in axially aligned but exploded relation, for
clarity.
[0035] Shown at the extreme left in FIG. 1 is an outer jacket 10,
to the right of which is a scraper element 12, followed by a washer
14 and a circlip 16. While FIG. 1 shows only one washer 14 and one
circlip 16, it is to be understood that the complete assembly
requires two washers and two circlips.
[0036] As best seen in FIG. 2, the outer jacket 10 has the shape of
a hollow circular cylinder with an outer cylindrical wall 18 and an
inner cylindrical wall 20. In the inner cylindrical wall 20 are
provided two spaced-apart grooves 22, each adapted to receive a
circlip 16. Each circlip 16 is sized so as to resiliently "snap"
into position within the corresponding groove 22. As best seen in
FIG. 1, each circlip 16 is a penannular member, shaped such that
the free ends 24 can resiliently approach each other to make the
effective diameter smaller and allow it to be snapped into
position.
[0037] The circlips 16 are spaced axially away from each other to
allow the inclusion of the two washers 14, each lying immediately
adjacent one of the circlips 16 (shown in broken lines within the
jacket 10), and also containing the scraper element 12, this lying
between the washers 14.
[0038] To avoid confusion, it should be explained that FIG. 2 shows
each circlip 16 in two positions: both outside and inside the
jacket 10, and similarly, each washer 14 is shown both outside and
inside the jacket 10. The inside positions for all such elements
are in broken lines.
[0039] Returning to FIG. 1, the scraper element 12 takes the form
of an elongate resilient wire bent to define a series of integral,
concatenated, resilient segments 26, with each pair of adjacent
segments 26 being connected through a geniculation 28. The
geniculations 28 are rounded. When so bent, the scraper element
consists of a series of relatively straight portions connected in
sequence by rounded portions. More accurately, the scraper element
12 of a preferred embodiment is formed by bending a resilient wire
to form a series of approximate triangles with blunt apices, in
such a way that each geniculation is at a location closely adjacent
to, but not coincident with, the locations of the geniculations
which are three segments away from the given geniculation in either
direction.
[0040] The scraper element 12 is received within a recess defined
by the jacket 10 and the two washers 14, this being identified by
the numeral 30 in FIG. 2.
[0041] As can be seen in FIG. 5, the result of bending the elongate
resilient wire into the shape seen in FIG. 1 is that substantially
all of the wire segments extend substantially along chords of the
aligned axial openings 32 which are defined by the washers 14.
[0042] To illustrate theoretically what is happening, attention is
directed to FIG. 3, which shows only a single wire segment 26a
extending along a chord of the opening 32. Comparing FIGS. 3 and 4,
it will be seen that when a tubular member (shown in transverse
section at 34 in FIG. 4) takes up a central position within the
opening 32, it can only do so by forcing the wire segment 26a
outwardly. However, because the wire is resilient, it will seek to
remain in the position of FIG. 3, and its outwardly deflection will
cause it to push inwardly against the outer surface of the tubular
member 34, thus allowing it to carry out a scraping and cleaning
action on the surface when the scraper 9 moves along the tubular
member 34. By arranging for substantially all of the wire segments
to press inwardly against the tubular member in the same way, there
will occur a multiple scraping action which is highly effective and
efficient.
[0043] As previously pointed out, FIG. 5 is a more accurate
depiction of the scraper configuration.
[0044] It should be further pointed out that the number of wire
segments seen in FIG. 1 is far less than the actual practical
number, which is closer to about 100.
[0045] In the embodiment shown in FIG. 6, the left side of the
jacket 10a is changed to a simple inward projecting flange 36,
which performs the same function as the leftward washer 14 (in FIG.
2).
[0046] Thus, it can be seen that the jacket 10, 10a, with two or
with one washer (held in place by a circlip 16) defines an inwardly
open circumferential recess 30 and two aligned axial openings
32.
[0047] To enhance the scraping function of the scraper element 12,
the resilient wire may be non-round in transverse section.
Preferably the resilient wire has a polygonal cross-section, which,
even more preferably, is a square cross-section.
[0048] It is to be understood that the scraper 9 would be mounted
in association with means adapted to support it in a position from
which it can surround the tubular member, and can be moved axially
relative to the tubular member. This is schematically shown in FIG.
7, depicting a tube 34, a scraper 9 connected to a carriage member
42 adapted to move longitudinally along a threaded screw 44. As the
screw 44 is rotated, the carriage 42 will be moved to the left or
to the right (depending upon the sense of the rotation), and will
carry the scraper 9 longitudinally of the tubular member 34.
[0049] While two embodiments of this invention have been
illustrated in the accompanying drawings and described hereinabove,
it will be evident to those skilled in the art that changes and
modifications may be made therein without departing from the
essence of this invention, as set forth in the accompanying
claims.
* * * * *