Patent Grant
7334587
The present invention is directed to an assembly for use in hydroblast cleaning and, in particular, the hydroblast cleaning of heat exchangers. A typical heat exchanger comprises an outer shell or housing, generally cylindrical, through which a plurality of individual fluid carrying tubes extend. The tubes are typically formed of a heat conductive material such that heat can be exchanged between the fluids flowing through the tubes and fluid flowing about the tubes. During use, heat exchangers become fouled with scale and debris and their efficiency is reduced. Cleaning of such devices typically includes the use of a hydroblasting process in which the interior of the heat exchanger tubes are subjected to a low volume but extremely high velocity water spray. The spray or jets of water generated during hydroblasting may generate several thousand pounds of force. Typically, the hydroblast cleaning of heat exchangers requires the exchanger to be removed from the process area and taken to a cleaning area, usually a large concrete pad where the exchangers are subjected to hydroblast cleaning. The water and debris driven from the heat exchanger are contained on the concrete pad and collected in a sump. The process sprays a considerable amount of water about the surrounding area and generally creates a mess. It would be highly desirable to provide an assembly for use in the hydroblast cleaning of such devices that could better contain the high velocity water and debris extracted therefrom for collection and disposal. It would also be highly desirable if such a system allowed heat exchangers to be cleaned in place. Such a system would not only avoid the mess created with the hydroblast cleaning process but also would result in a substantial savings of time and expense in connection with the cleaning of typical heat exchangers.
Briefly, the present invention comprises an assembly for use in the hydroblast cleaning of heat exchangers. The assembly includes an end shield that is spaced from and axially aligned with the downstream end of the heat exchanger and an annular shield that surrounds the area between the end shield and the end of the heat exchanger. The end shield and annular shield cooperate to substantially contain the exiting spray and the debris driven from the heat exchanger tubes. An energy absorbing element may be mounted adjacent the downstream end of the heat exchanger for reducing the force of the extremely high velocity jets of water exiting the heat exchanger tubes. A waterproof flexible shroud is disposed about the shield portions of the assembly, the energy absorbing element and the downstream end of the heat exchanger. An aperture is provided in the underside of the annular shield so that the water and debris collected therein will drain into the shroud. A nozzle is provided in the lower portion of the shroud for draining the water and debris into a detachable hose or a portable collection device positioned on the ground below the shroud.
The portable collection device employed in the present invention is preferably is formed of a flexible and durable plastic material and defines a bottom surface, upstanding perimeter wall portions which are moveable between upright and folded positions and foldable support members. As a result of its configuration, the device can be readily folded into a compact disposition for travel and storage or disposed on the ground in an open upstanding position for collecting the spray and debris from the hydroblast cleaning of the heat exchanger tubes.
A portable washing station also is preferably provided for collecting any back spray and debris at the upstream end of the heat exchanger where the worker directs the high velocity water spray into the heat exchanger tubes. The station is positioned about the upstream end of the heat exchanger and houses both the upstream end of the heat exchanger and the person conducting the hydroblast cleaning. The washing station comprises a horizontal waterproof flooring having flexible side walls, a raised floor support, preferably in the form of a grid walkway which supports the worker above the flooring, a frame comprised of vertical and horizontal support members, a flexible water impermeable top carried by the frame and side curtains, preferably formed of a plurality of depending adjacent plastic strips, are carried by an upper portion of the frame so as to extend between the upper and lower portions of the frame, preferably on at least three full sides of the station. The heat exchanger extends through the open side of the station where the worker can hydroblast clean the exchanger tubes without obstruction. The flooring, attached side walls and the curtains defined on the remaining sides of the station will act to substantially contain any back spray within the station while protecting the surrounding area.
Through the aforesaid combination, the heat exchanger tubes can be thoroughly cleaned by a hydroblast process either in a designated cleaning pad area or substantially in place, the water and debris generated by the cleaning process is readily contained and collected for disposal and the individual conducting the hydroblast cleaning is maintained in a substantially protected environment. The entire assembly is lightweight and portable for use in industrial plants with tightly spaced equipment.
Referring now in detail to the drawings, the cleaning assembly 10 of the present invention is illustrated in use in the drawings in connection with the hydroblast cleaning of the flow tubes in a conventional cylindrical heat exchanger 12 (the interior flow tubes, baffles, support plates, etc. not being shown and the front and rear heads removed). The heat exchanger 12 defines a rear or upstream end 14, a forward or downstream end 16, and end flanges 14a and 16a. It is to be noted that the terms upstream end and downstream end are used herein with reference to the direction of the hydroblast cleaning spray as many heat exchangers are symmetrical with their front and rear heads removed, thus allowing the cleaning assembly 10 of the present invention to be secured to either end of the heat exchanger for cleaning the tubes therein.
In the embodiment of the invention illustrated in the drawings, the cleaning assembly 10 includes an energy absorbing element 18 for reducing the force of water jets exiting the heat exchanger. Further experimentation with cleaning assembly 10 may indicate that the use of an energy absorbing element in the assembly is not necessary. If included, the element absorbing element 18 can be of a variety of different configurations and is mounted on the downstream end flange 16a of the heat exchanger so as to be adjacent the downstream end 16 of the heat exchanger. In the presently preferred embodiment, the energy absorbing element 18 is mounted on the end flange 16a by means of a plurality of elongated threaded metal rods 20 which extend through apertures disposed in end flange 16a and are secured by threaded fasteners 22 (preferably wing nuts) adjacent the upstream end of flange 16a. The rods 20 project downstream from the end flange 16a in a parallel array. In its preferred configuration, the energy absorbing element 18 comprises a plurality of depending flexible ropes formed of a nylon or other suitable material secured at their upper end to a horizontally disposed angle iron 24 provided with two laterally spaced apertures 24a therein adapted to receive portions of the two upper rods 20 such that the energy absorbing element 18 can be mounted thereon and extend across the downstream end of the heat exchanger. Other forms of energy absorbing elements could include but are not limited to perforated metal panels and wire mesh screens.
A circular containment shield 26, preferably formed of a durable plastic material is mounted on rods 20 downstream of the energy absorbing element 18. Shield 26 can be square, circular or of any other desired shape and defines a transverse dimension substantially equal to the diameter of the end flange 16a on the heat exchanger. Differently sized shields and energy absorbing elements would be provided for differently sized heat exchangers. Shield 26 is provided with apertures 26a therein for receiving the downstream end portions of mounting rods 20 to effect the mounting of the containment shield in axial alignment with the energy absorbing element 18 and the central axis of the heat exchanger 12. The containment shield 26 is secured in place by fasteners 22 (e.g. wing nuts) that threadably engage rods 20 thereby fixing the shield 26 and energy absorbing element 18 in axial alignment. Rods 20 are preferably formed of about 0.25 inch diameter threaded steel rods and thus provide inherent flexibility to accommodate the mounting of the shield and energy absorbing element in substantial alignment.
A relatively thin and flexible water-impermeable sheet 30, preferably formed of galvanized steel and having an axial length of about 12-18 in., depending on the size of the unit, is wrapped about rods 20 between the containment shield 26 and the energy absorbing element 18 and secured in a cylindrical disposition by straps 32 and buckles 34 so as to provide an annular shield that cooperates with the end shield 26 to substantially contain the spray and debris passing through the heat exchanger tubes during cleaning. It is to be understood that any suitable fastener could be employed to releasably secure sheet 30 about rods 20. Alternatively, the end and annular containment shields 26 and 30 could be formed of a single-piece construction. An aperture 36, approximately 4 inches in diameter, is formed in sheet 30 so as to be positioned at the bottom of the annular shield upon the sheet being secured in a cylindrical configuration about rods 20 so as to define a drain for the water and debris.
A containment cover or shroud 38, preferably formed of an 18 oz. vinyl so as to render the cover flexible and waterproof, is disposed about end shield 26, the annular shield 30, the energy absorbing element 18, the end flange 16a on the heat exchanger and a portion of the downstream end of the heat exchanger. An elastic band 40 is preferably formed in the upstream portion of shroud 38 so as to secure the cover in place about the downstream body portion of the heat exchanger as best seen in
In one embodiment of the present invention (see
If desired, a second energy absorption element 60 can be mounted on a similarly positioned plurality of horizontal extending rods 62 carried by the upstream end flange 14a of the heat exchanger 12 such that element 60 is spaced from and axially aligned with the upstream end of the heat exchanger. Element 60 would preferably be of the same configuration as energy absorbing element 18 although other configurations and mountings could be employed. Element 60 would allow the hydroblasting wand to be inserted between the depending ropes or other elements thereon by the operator, allow the operator to freely move the wand during cleaning and absorb the energy of any high velocity spray bouncing off the heat exchanger and back towards the operator. Element 60 would also deflect some of the back spray away from the operator.
A portable lightweight washing station 70 is preferably provided at the upstream end of the heat exchanger for collecting the back spray deflected off the heat exchanger during cleaning. In its preferred configuration, the station 70 is of a generally square configuration and is positioned on a second spill containment berm 72, substantially identical to containment berm 50, and additionally includes an elevated grid walkway 74 preferably formed of a plastic or other lightweight durable material and elevated slightly above the flooring of containment berm 72. The washing station 70 has a lightweight frame 76 comprising vertical and horizontal elements 76a and 76b, a plastic lightweight cover 78 and a plurality of adjacent curtains 80 hanging from an upper portion of frame 76 so as to extend about at least three of the sides of the station 70. Curtains 80 preferably are each comprised of a plurality of depending plastic strips 81 hanging in close disposition so as to define the curtains. Alternatively, and more economically, each curtain could be formed of a single sheet of plastic material, preferably having a vertical slit provided therein for access to the interior of the station through the sides or rear thereof. The slits could be left open or be provided with a zipper closure. Such embodiments would be more economical than the use of adjacent plastic strips 81 and could be disposable.
Station 70 is positioned such that the upstream end 14 of the heat exchanger extends into the interior of the station through the open side not covered by curtains 80. If desired, depending plastic strips or narrow curtains could be extended across lateral portions of the open end of the shelter, leaving a portion of that side of the shelter open so that the end 14 of the heat exchanger can extend therethrough unimpeded by the plastic strips or curtains. So positioned, the station 70 allows the worker to stand within the shelter while he or she directs the high velocity water spray from the hydroblasting cleaning wand into the heat transfer tubes. The return spray bouncing off of the heat exchanger or the components thereof is then largely retained within the station 70, protecting the surrounding area from the water and debris. Preferably, the plastic curtains extending about the sides of the washing station is defined by thin rectangular vinyl strips approximately 6 inches wide by 0.060 inches thick.
Various changes and modifications can be made in carrying out the present invention without departing from the spirit and scope thereof. Insofar as these changes and modifications are within the purview of the appended claims, they are to be considered as part of the present invention.
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|---|---|---|---|
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| Number | Date | Country | |
|---|---|---|---|
| 20060266390 A1 | Nov 2006 | US |
