Adjustable tube-cleaner device

Adjustable tube-cleaning device (10) has a scraper sub-assembly (16) which includes a substantially annular sleeve (32) on a circumferential outer surface (30) of an elastic core (14) which, in turn, is mounted on a central shaft (12). The sleeve (32) contracts toward a pre-formed, non-loaded configuration in which it has a smaller internal diameter than a diameter of the outer surface of the elastic core. The scraper assembly further includes a plurality of scrapping vanes (32) held by the sleeve to the elastic core and extending radially outwardly from the elastic core. Each of the scraping vanes has a scraping edge (54) directed radially away from the elastic core. The elastic core is substantially cylindrical and surrounds the central shaft between anchor (18) and adjustable compression member (26). The scraping vanes in one row of vanes can be placed on an angle relative to a plane perpendicular to an axis of the central shaft.

BACKGROUND OF THE INVENTION 
This invention relates to devices for cleaning insides of tubes or pipes, 
such as those found in heat exchangers, condensers, and other applications 
where tubes are susceptible to scale build-up, bio-fouling, or other 
heat-transfer-inhibiting deterioration. 
Heat exchangers for steam turbines have anywhere from 3,500 to 70,000 tubes 
therein, each being from 20 to 115 feet long. The efficacy of these tubes 
as heat exchangers, depends to a large extent, on the speed with which 
heat is transferred through their walls. "Build-up" on interior surfaces 
of the walls of these tubes detracts from their ability to transfer heat. 
Thus, tube cleaning devices are used to clean interior surfaces of such 
tubes, as well as of other tubes and pipes. 
U.S. Pat. No. 576,425 to Bilton et al discloses an appliance for scraping 
interiors of water mains or pipes including a screw-threaded spindle with 
two cones mounted thereon. Lever-like cutter blades mounted on each of the 
cones are expanded and contracted by stout rubber washers and regulating 
nuts mounted on the spindle behind the cutter blades. Thus, a scraping 
power of the cutter blades is obtained by adjusting each of the regulating 
nuts, which respectively bear on the rubber washers, for, in turn, bearing 
on the cutter blades. 
U.S. Pat. No. 5,305,488 to Lyle similarly discloses a tube-cleaning tool 
having a central shaft and two truncated-cone-shaped cutters with cutter 
blades, mounted thereon. In this regard, each of the cutters has a hole 
through a central axis thereof through which the shaft passes so that the 
cutters can slide along the shaft. Also mounted on the central shaft, one 
adjacent each respective cutter, are flexible bushings to press against 
the cutters and exert outward pivoting pressure on the lever-like cutter 
blades, as in Bilton et al. In Lyle, the cutters can slide along the shaft 
and press against each other, so that adjustment of cutter blades of both 
cutters with one adjustment is allowed. The shaft used to secure the 
cutters and flexible bushings to one another is formed with a twist in 
order to offset the two cutters with respect to one another. The Lyle 
device is propelled through an interior of a tube by fluid projected 
against a separate tail portion on the device. The tail portion is formed 
with openings that allow some fluid to flush through the tail portion to 
the cutter blades of the device. The Lyle device can be formed with a 
flexible shaft to enable it to move through "U" bent tubing. 
Other similar lever-blade expandable tube, or pipe, cleaning devices are 
disclosed in U.S. Pat. Nos. 1,122,246 to Beam; 1,608,347 to Thompson et 
al; 1,612,842 to Thompson et al; 2,402,796 to Wood; 2,636,202 to Hinzman; 
and 4,891,115 to Shishkin et al. 
There are several difficulties with these tube cleaning devices. For one 
thing, it is very difficult and expensive to refurbish scraper blades 
thereof when they become worn because they attach to and lever from hubs. 
Also, it is difficult to control, and to make uniform, forces exerted by 
their scrapers on interior walls of tubes because the pressures their 
scrapers exert depend upon flexibilities of cutter blades as well as on 
force applying mechanisms at the hubs, including in some cases the 
elasticities of rubber washers, or bushings. In this regard, in both 
Bilton et al and Lyle, as resilient members are compressed, lever cutting 
blades pivot outwardly from central axis areas, or hubs (cones), thereby 
causing exaggerated motion of outer scraping areas of the lever cutting 
blades. This aggregated motion, along with the flexibility of the lever 
cutter blades, makes it difficult to achieve a predictable final adjusted 
movement and a predictable scraping pressure. 
It is an object of this invention to provide an adjustable tube-cleaner 
device that can be manufactured and assembled simply and economically, 
that can be economically refurbished, and that can be reliably and 
accurately adjusted to produce a predictable scraping pressure with a fine 
movement adjustment. 
SUMMARY OF THE INVENTION 
According to principles of this invention, an adjustable tube-cleaner 
device has a scraper assembly which includes a substantially annular 
sleeve mounted on a circumferential outer surface of an elastic core 
which, in turn, is mounted on a central shaft. The sleeve contracts toward 
a pre-formed configuration in which it has a smaller internal diameter 
than a diameter of the outer surface of the elastic core. The scraper 
assembly further includes a plurality of scraping vanes held by the sleeve 
to the circumferential outer surface of the elastic core for extending 
radially outwardly from the sleeve. Each of the scraping vanes has a 
scraping edge directed radially away from the elastic core. The elastic 
core is substantially cylindrical and surrounds the central shaft between 
anchor and adjustable compression members. 
The radial positions of the scraping edges can be adjusted relative to the 
central shaft by moving adjustable compression members along the shaft 
toward and away from one another to thereby compress and decompress the 
elastic core. This, in turn, radially expands and contracts the core outer 
surface and the resilient sleeve and scraping vanes mounted thereon for 
controlling a tightness with which the scraping edges of the scraping 
vanes fit in a tube being cleaned. 
In one embodiment, scraping vanes in one row of scraping vanes are angled 
relative to a plane perpendicular to an axis of the elongated shaft for 
automatically rotating the tube cleaning device.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
An adjustable tube-cleaning device 10 comprises generally a central shaft 
12, a substantially-cylindrical elastic core 14, and a scraper subassembly 
16. 
The central shaft 12 has an anchor, in the form of a head, 18 at one end 
thereof and threads 20 at an opposite threaded end thereof. An anchor 
washer 22 is mounted on the central shaft 12 abutting against the head 18 
while an adjustable washer 24 is mounted on the central shaft 12 at the 
threads 20 abutting against a nut 26. The nut 26 is engaged with the 
threads 20 to form an adjustable compression device. 
In one embodiment, the elastic core 14 is cylindrically shaped with a 0.549 
inch outer surface diameter, with the central shaft 12 passing through a 
central bore 28 thereof, with the elastic core 14 being positioned between 
the anchor washer 22 and the adjustable washer 24. As can be seen in FIG. 
2, outer perimeters of the anchor washer 22 and the adjustable washer 24 
have greater circumferences than a cylindrically-shaped core outer surface 
30 of the elastic core 14. In a preferred embodiment, the elastic core 14 
is constructed of an expandable rubber, however, other elastic materials 
can also be used such as a closed cell polyurethane foam. 
In the embodiment of the tube-cleaning device 10 depicted in FIGS. 1-4, the 
scraper subassembly 16 includes an annularly-shaped resilient, or 
flexible, sleeve 32 and, separate, scraping vane elements 34. 
In the depicted embodiment of FIGS. 1-3, the annularly-shaped resilient 
sleeve 32 is constructed of spring steel having a thickness of 0.04 
inches. The annularly-shaped resilient sleeve 32 thus forms a cylinder, as 
can be seen in FIGS. 1-3 which, if it were allowed to relax to an unloaded 
unstressed configuration, could have an inner diameter of around 0.767 
inches for a tube-cleaning device used for scraping tubes having 1 inch 
outer diameters, as will be further described below. The length L of the 
sleeve 32 in one embodiment is around 1.188 inches. In the FIG. 1 
embodiment the resilient sleeve 32 is cut longitudinally, but at a 
diagonal with the length, so that it has first and second diagonal ends 36 
and 38 and it is pre-stressed so that when it is allowed to go to the 
unloaded, unstressed, configuration the first and second diagonal ends 36 
and 38 overlap as is depicted in FIG. 1. 
Describing now the scraping vane elements 34, each of these is separate 
from the other vane elements and each is generally L-shaped, as can 
clearly be seen in FIG. 4, with a base leg 40 and a scraping leg 42 
perpendicular to the base leg 40. The base leg 40 is somewhat rounded in 
its width so as to properly fit on the core surface 30. In this respect, 
first and second opposite rows 44 and 46 of vane elements 34 are placed on 
the core surface 30 with toes 48 of the base legs 40 of the first row 44 
pointing toward those of the second row 46, and with the scraping legs 42 
of all of the vane elements 34 extending perpendicularly away from the 
core surface 30, as can be clearly seen in FIGS. 1-3. The scraping vane 
elements are constructed of 0.022 inch thick spring steel in the preferred 
embodiment. 
The toe 48 of each of the scraping vane elements 34 is narrower than the 
scraping leg 42, with the toe 48 and the scraping leg 42 being positioned 
at opposite ends of the base leg 40. In this regard, shoulders 50 are cut 
in each side of the base leg 40 between the toe 48 and the scraping leg 42 
to narrow that portion of the base leg 40, thereby forming the toe 48. As 
can be seen in FIGS. 1 and 3, the shoulders 50 of adjacent scraping vane 
elements 34 in the first row 44 form slots into which the toes 48 of 
scraping vane elements from the second row 46 are inserted, and vice 
versa. In this manner, the scraping vane elements 34 of the first and 
second rows 44 and 46 inter-engage so that the respective scraping legs 42 
in the first and second rows 44 and 46 are offset from one another. In one 
embodiment, the rows of scraping vanes, themselves, are separated from one 
another by 1.250 inches. 
When the embodiment of the tube-cleaning device 10 of FIGS. 1-4 are fully 
assembled, the base legs 40 of the first and second rows 44 and 46 of 
scraping vane elements 34 are surrounded by the resilient sleeve 32, as 
can be seen in FIGS. 1-3, for holding the scraping vane elements 34 of the 
first and second rows 44 and 46 tightly against the outer core surface 30 
of the elastic core 14. In this regard, the scraper subassembly 16, which 
is formed of the resilient sleeve 32 and the scraping vane element 34 of 
the first and second rows 44 and 46 are supported by the core surface 30 
and the resilient sleeve 32 in this embodiment. In the depicted embodiment 
there are six (6) scraping vane elements 34 in each row 44, 46, but in 
other embodiments there are other numbers of scraping vane elements (such 
as eight (8)). 
In operation, the elements of the tube-cleaning device 10 are assembled to 
appear as is depicted in FIGS. 1-3. For describing the manner of 
assembling, it will be assumed that the tube-cleaning device 10 will be 
used for cleaning tubes having a one inch outer diameter with 18, 20, or 
22 gauge wall thickness. For this embodiment, the following dimensions 
could be used with the core 10 being in a relaxed condition (see FIG. 15): 
______________________________________ 
elastic core 14 relaxed diameter CD 
0.623 inch 
scraping leg 42 height, 0.145 inch each .times. 2 = 
+ 0.290 inch 
vane scraping diameter VD 
0.913 inch 
inner diameter SD of relaxed sleeve 32 
0.767 inch 
elastic core 14 relaxed diameter CD 
- 0.623 inch 
space between relaxed core 14 and relaxed sleeve 32 
0.144 inch 
______________________________________ 
A 1 inch OD pipe has the following internal diameters, depending on its 
gauge: 
______________________________________ 
18 gauge ID 0.902 inch 
20 gauge ID 0.930 inch 
22 gauge ID 0.944 inch 
______________________________________ 
Thus, when the core is in the relaxed position, there is a 0.144 inch space 
between the outer surface of the core and the inner surface of the relaxed 
sleeve 32. However, the thickness of the scraping vane elements 34 which 
are placed in this space are 0.022 inch.times.2=0.044, which does not fill 
this 0.144 inch space between the outer surface of the core 14 and the 
inner surface of the sleeve 32. For this reason, it is quite easy to 
insert the base legs 40 of the scraping vane elements 34 between the 
resilient sleeve 32 and the elastic core 14. Once all of the scraping vane 
elements 34 are in place, as is shown in FIGS. 1 and 2, the nut 26 is 
tightened so that the adjustable washer 24 is driven toward the anchor 
washer 22, thereby squeezing the elastic core 14 and forcing its outer 
surface, as well as the scraping vane elements 34, outwardly. Eventually, 
elements of the tube cleaning device 10 will have the following 
dimensions: 
______________________________________ 
inner diameter SD of sleeve 32 
0.767 inch 
elastic core 14 diameter CD 
- 0.723 inch 
space between core 14 and sleeve 32 
0.044 inch 
______________________________________ 
Thus, the base legs 40 of the scraping vane elements 34, which are 0.022 
inches thick.times.2=0.044 inches fits exactly between the sleeve and the 
core and is held therebetween by friction. In this configuration the 
following dimensions exist: 
______________________________________ 
elastic core 14 diameter CD 
0.723 inch 
scraping leg 42 height 0.145 inch each .times. 2 = 
+ 0.290 inch 
vane scraping diameter VD 
1.013 inch 
______________________________________ 
This is the size of the tube-cleaning device 10 when it is to be inserted 
into a 22 gauge 1 inch tube, which has an inner diameter of 0.944 inches. 
When it is intended to use this tube-cleaning device for cleaning a tube, 
such as a condenser tube 52 of a condensing system in a steam power plant 
(not shown) a tube-cleaning device 10 is chosen which, when its elastic 
core is not substantially compressed between the anchor and adjustable 
washers 22 and 24, scraping edges 54 of its first and second rows 44 and 
46 of scraping vane elements 34 define circles having diameters which are 
in a range of slightly smaller than to slightly larger than an interior 
diameter of the tube 52. The adjusting nut 26 is then tightened on the 
threads 20 of the central shaft 12 to drive the adjustable washer 24 
toward the anchor washer 22, thereby compressing the elastic core 14 
between the anchor and adjustable washers 22 and 24. This, in turn, causes 
the outer core surface 30 to move radially outwardly, thereby driving the 
scraping vane elements 34 outwardly and expanding the resilient sleeve 32 
so that overlapping first and second end portions 36 and 38 of the 
resilient sleeve 32 slide on one another to create less overlap. During 
this procedure, the scraping vane elements 34 are continuously held 
tightly against the core surface 30 by the resilient sleeve 32. This 
adjustment is made until the scraping edges 54 fit snugly within the inner 
diameter D of the tube 52. At this point, the tube-cleaning device 10 is 
inserted into one end of the tube 52 and fluid pressure is applied to the 
tube 52 behind the tube-cleaning device to drive the tube-cleaning device 
through the tube 52. As the tube-cleaning device 10 is driven through the 
tube 52, its scraping edges 54 scrape along the interior surface of the 
tube 52 and thereby scrape off scale, fouling, or other build-up in the 
tube 52. The diameter of the outer core surface can be increased by at 
least 5% by tightening the nut 26. 
In an enhanced embodiment of the structure depicted in FIGS. 1-3, the 
resilient sleeve 32 has a relaxed inner diameter of 0.60 inches. This 
inner diameter is smaller than the relaxed outer diameter CD of the 
elastic core 14 which, as is mentioned above, is 0.63 inch. When such a 
sleeve is in this relaxed condition, its ends 36 and 38 overlap. In order 
to place the elastic core 14 and the based legs 40 of the scraping vane 
element 34 between such a sleeve and the elastic core, one must expand the 
sleeve. A jig (not shown) can be employed for this purpose. Once the 
sleeve 32 and the scraping vane elements 34 are mounted on the elastic 
core 14, the first and second ends 36 and 38 of the resilient sleeve are 
held slightly spaced from one another to form a gap therebetween. In 
another embodiment, the height of the scraping leg 42 is 0.150 inch rather 
than 0.145 inch as is discussed in the example given above. All of the 
other dimensions can remain the same in this embodiment, however it should 
be understood that these dimensions can vary from one embodiment to the 
next and that the dimensions given above are exemplary of the particular 
embodiments of the invention described. Also, elements from the various 
embodiments can be combined in other ways. 
FIG. 5 depicts a second embodiment U-shaped scraping vane element 56 which 
forms scraping legs 42a and 42b for forming first and second rows similar 
to the first and second rows 44 and 46 of the FIG. 1 embodiment. Although 
the scraping legs 42a and 42b are shown in FIG. 5 directly opposite one 
another it would also be possible of offset them by properly shaping a 
base 40a of the U-shaped scraping vane element 56. Also, a scraping vane 
element 58 could be constructed as shown in FIG. 8, which is also 
U-shaped. 
FIG. 7 depicts another enhancement of the embodiment of FIGS. 1-4. The 
scraping vane element 60 (FIG. 7) of the FIG. 6 embodiment is like the 
scraping vane element 34 of the FIG. 1 embodiment, with the exception that 
its scraping leg 62 is on a 5.degree.-20.degree. angle (10.degree. in a 
preferred embodiment) relative to a plane perpendicular to the length of 
its base leg 64. Thus, when the scraping element 60 is mounted on the 
elastic core 14, the scraping leg 60 is at an angle to a plane 
perpendicular to the axis of elongation of the central shaft 12. 
In a tube-cleaning device 66 of the FIG. 6 embodiment, scraping vane 
elements 34 are used to form the first row 44 while the angled scraping 
vane elements 60 are used to form a second row 46a. The tube-cleaning 
device 66 is used in the same way as is the tube-cleaning device 10, 
however, when it is shoved through the tube 52 by fluid pressure the 
angled scraping legs 62 are driven by the fluid pressure to cause the 
tube-cleaning device 66 to rotate about the axis of its central shaft 12, 
thereby enhancing a cleaning effect of the tube-cleaning device 66. 
FIG. 9 depicts an embodiment of this invention in which a resilient sleeve 
68 and scraping vane elements 70 are formed as a scraper subassembly 16a 
which is made of one piece of spring steel. The scraper subassembly 16a 
can be constructed as one endless circular sleeve, or, it can have a break 
72 therein with overlapping, or not overlapping ends. Again, the scraper 
subassembly 16a is held on the elastic core 14 primarily by compressing 
generated friction. It would also be possible to combine a scraper 
subassembly 16a with an outer resilient sleeve 32, by placing the outer 
resilient sleeve 32 about the scraper subassembly 16. 
FIGS. 10 and 11 depict a modified first embodiment of this invention which 
is identical to the embodiment of FIG. 1 with the exception that the first 
and second diagonal ends 36 and 38 of the resilient sleeve 32 do not 
overlap as they do in the FIG. 1 embodiment, rather there is a gap 74 of 
from 0.1-0.2 inches between the first and second diagonal ends 36 and 38. 
In another embodiment, which is identical with, or similar to, the 
embodiment depicted in FIGS. 10 and 11, the first and second ends 36 and 
38 are not diagonal at all, but rather extend parallel to the axis of the 
central shaft 12. In fact, a cross-sectional view of a slightly-modified 
such tube-cleaning device 10 is depicted in FIG. 13. The embodiment 
depicted in FIG. 13 is identified as a seventh embodiment in that it not 
only has a gap 74 which is parallel with the axis of the central shaft 12 
but in that it has the additional feature that the scraping legs 42 of the 
scraping vane elements 34 are fanned at their side edges 76 so that gaps 
78 between the scraping legs 42 are quite small. This allows the scraping 
legs 42 to scrap greater areas along a tube being cleaned. 
An eighth embodiment depicted in FIG. 14 is the same as the embodiment 
depicted in FIG. 13 with the exception that instead of having only one 
resilient sleeve 32, there are two concentric resilient sleeves, namely, 
an inner resilient sleeve 80 and an outer resilient sleeve 81. Both the 
inner and outer resilient sleeves 80 and 81 have gaps 82 and 84. An 
advantage in having a gap, such as the gap 74 of the FIG. 13 embodiment, 
and the gaps 82 and 84 of the FIG. 14 embodiment, rather than an overlap, 
as is shown in FIG. 1, is that the sleeve applies a more even pressure on 
the scraping vane elements so that some scraping legs 42 of the scraping 
vane elements 34 do not protrude radially outwardly more than other. The 
two resilient sleeves of the eighth embodiment of FIG. 14 apply the 
pressure yet more uniformly. FIG. 14 also shows the flared, or fanned, 
scraping legs 42 of the scraping vane element 34. 
FIG. 15 is simplified to only show the elastic core 14 and the scraping 
vane elements 34, with their flared scraping legs 42. The dimensions 
referred to above are also designated on this drawing. 
Finally, FIG. 12 depicts a sixth embodiment of this invention in which 
three rows of scraping vane elements 34a, 34b, and 34c are all mounted on 
an extra long elastic core 14'. In this case two axially-spaced resilient 
sleeves 32a and b are required, with the resilient sleeve 32a holding the 
scraping vane elements 34a and 34b to the elastic core 14' and the 
resilient sleeve 32b holding the scraping vane elements 34c to the elastic 
core 14'. In another embodiment, not depicted, rather than having a single 
elongated elastic core 14', there are two elastic cores, one being of a 
length of the elastic core 14 of the FIGS. 1 and 10 embodiments, and the 
other being a shorter elastic core on embodiment, not depicted, rather 
than having a single elongated elastic core 14', there are two elastic 
cores, one being of a length of the elastic core 14 of the FIGS. 1 and 10 
embodiments, and the other being a shorter elastic core on which the 
scraping vane elements 34c are mounted. In this case a washer would be 
inserted between the elastic core on which the scraping vane elements 34b 
are mounted and the elastic core on which the scraping vane elements 34c 
are mounted. 
An important benefit of the tube-cleaning device of this invention is that 
since the scraping vane elements thereof are only held primarily by 
friction to the elastic core, they can be relatively easily replaced for 
refurbishing the tube-cleaning device 10 by merely loosening the resilient 
sleeve. In this regard, the scraping edges 54 of the scraping legs 42 
periodically wear so that the scraping vane elements must be replaced. 
Another benefit of this invention related to its shape and size is that it 
does not require a special separate fluid contact element, or impeller, to 
drive it through tubes because the scraping legs and the washers 
themselves substantially fill the tubes, thereby forming an adequate fluid 
contact element which also allows passage of some fluid for cleaning. In 
fact in the FIG. 6 embodiment, where there are angled scraping legs, the 
scraping legs also serve to rotate the tube cleaning device as it is being 
driven along a tube for enhancing its cleaning ability. 
Yet another benefit of this invention is that radially inside ends of the 
scraping legs bare directly against the elastic core rather than via 
metallic spring leaves as in most prior-art devices. Because of this, the 
pressure with which the scraping legs 42 exert against inside surfaces of 
tubes is dependent primarily only on the elasticity and resilience of the 
elastic core 14. Thus, the scraping pressure exerted by the scraping legs 
42 is more predictable and easier to regulate than it is for most 
prior-art tube-cleaning devices. 
Each scraping vane element is easily inserted into, and removed from, the 
tube-cleaning device of this invention by relieving the tension on the 
elastic core 14 by loosing the nut 26, placing it into the enlarged space 
between the core and the sleeve, and than again tightening the nut 26. 
The invention has been particularly shown and described with reference to a 
preferred embodiment. It will be understood by those skilled in the art 
that various changes in form and detail may be made therein without 
departing from the spirit and scope of the invention.