Abstract
A firetube scraper device comprising: at least one carriage assembly mounted on the firetube; a drive line and drive means for displacing the carriage assembly longitudinally along the firetube; wherein said carriage assembly surrounding the entire circumference of the firetube and comprising at least one row of scraper fins, each of said scraper fins having an inner surface adapted to frictionally engage an outer firetube surface defined by at least an upper portion of the surface of the firetube exposed to contaminants deposited onto a firetube surface.
Claims
1. A firetube scraper device comprising: at least one carriage assembly mounted on the firetube; a drive line and drive means for displacing the carriage assembly longitudinally along the firetube; wherein said carriage assembly surrounding the entire circumference of the firetube and comprising at least one row of scraper fins, each of said scraper fins having an inner surface adapted to frictionally engage an outer firetube surface defined by at least an upper portion of the surface of the firetube exposed to contaminants deposited onto a firetube surface; and wherein each scraper fin has a front side and a backside, the front side having a curvature adapted to frictionally contact the external surface of the firetube, and wherein the backside of each scraper fin comprises a plurality of projections substantially perpendicular to the backside.
2. The firetube scraper device according to claim 1, further comprising a spraying system comprising a plurality of nozzles positioned on an arm extending laterally from a desanding line located substantially above and parallel to the drive line.
3. The firetube scraper device according to claim 2 wherein the carriage assembly further comprises two opposite ends flexibly connected to one another to surround the circumference of the firetube.
4. The firetube scraper device according to claim 1, wherein the at least one row of scraper fins includes at least two rows with scraper fins that are staggered relative to one another.
5. The firetube scraper device according to claim 1, wherein each one of the plurality of the rows of scraper fins substantially surround the circumference of the firetube.
6. The firetube scraper device according to claim 1, wherein each one of the scraper fins has a curved front surface adapted to frictionally engage the curvature of the firetube.
7. The firetube scraper device according to claim 1, wherein backside comprising fastening means positioned on the projections for securing the scraper fin to the carriage assembly.
8. The firetube scraper device according to claim 7, wherein backside comprising at least one lateral aperture located on a projection, said aperture adapted to receive a scraper fastening means.
9. The firetube scraper device according to claim 8, wherein the scraper fastening means is a rod adapted to be inserted through an aperture located on the clamp arm and through the aperture located in the projection of the scraper fin.
10. The firetube scraper device according to claim 1 wherein the carriage assembly comprises: a main overhead carriage member operationally connected to the drive line; and at least one pair of clamp arms, each clamp arm having two extremities; wherein each one of said clamp arm having a first extremity hingedly connected to the main overhead carriage member and a second extremity connected to a second extremity of the opposite clamp arm by fastening means.
11. The firetube scraper device according to claim 10, wherein each one of said clamp arms having an elongated arcuate shape adapted to contour the curvature of the firetube.
12. The firetube scraper device according to claim 11, wherein the fastening means is a spring adapted to resiliently secure the opposing second extremities of the at least two clamp arms to provide frictional contact of the scrapers onto the firetube.
13. The firetube scraper device according to claim 10, wherein the fastening means are selected form the group consisting of: springs; nuts and bolts, clamps.
14. The firetube scraper device according to claim 1, wherein the carriage assembly comprises two pairs of clamp arms, each pair spaced apart from one another by at least one row of scraper fins.
15. The firetube scraper device according to claim 14, wherein each clamp arm has a plurality of spaced apertures located along a side thereof and adapted to receive therethrough a scraper fin fastening means.
16. The firetube scraper device according to claim 15, wherein the said scraper fin fastening means is a rod.
17. The firetube scraper device according to claim 1, wherein the outer firetube surface defined by at least an upper portion of the surface of the firetube exposed to contaminants deposited onto the firetube surface is substantially the outer firetube surface defined as the uppermost quadrant of said firetube.
18. The firetube scraper device according to claim 1, wherein the outer firetube surface defined by at least an upper portion of the surface of the firetube exposed to contaminants deposited onto the firetube surface is substantially the outer firetube surface defined as the upper half of said firetube.
19. A firetube scraper device comprising at least one carriage assembly; a drive line and drive means operatively connect to the carriage assembly and adapted to displace such longitudinally along the firetube; a desanding line located substantially above and parallel to the drive line, said desanding line comprising a spraying system adapted to spray a liquid onto the carriage assembly; wherein said carriage comprising a plurality of rows of scraper fins arranged around the circumference of the carriage assembly so as to frictionally contact an external surface of the firetube.
Description
BRIEF DESCRIPTION OF THE FIGURES
(1) The invention may be more completely understood in consideration of the following description of various embodiments of the invention in connection with the accompanying figure, in which:
(2) FIG. 1 is a perspective view of the firetube scraper device according to a preferred embodiment of the present invention;
(3) FIG. 2 is a side view of the firetube scraper device according to a preferred embodiment of the present invention;
(4) FIG. 3 is a cropped side view of the firetube scraper device according to a preferred embodiment of the present invention;
(5) FIG. 4 is a close up side view of the drive rod assembly of the firetube scraper device according to a preferred embodiment of the present invention;
(6) FIG. 5 is a close up side view of the beta drive system of the firetube scraper device according to a preferred embodiment of the present invention;
(7) FIG. 6 is a perspective view of the beta drive system of the firetube scraper device according to a preferred embodiment of the present invention;
(8) FIG. 7 is a side view of the beta drive system of the firetube scraper device according to a preferred embodiment of the present invention;
(9) FIG. 8 is a side view of the carriage assembly of the firetube scraper device according to a preferred embodiment of the present invention;
(10) FIG. 9 is a close up perspective view of the spring retainer of the carriage assembly of the firetube scraper device according to a preferred embodiment of the present invention;
(11) FIG. 10 is a top view of the carriage assembly of the firetube scraper device according to a preferred embodiment of the present invention;
(12) FIG. 11 is a front view of the carriage assembly of the firetube scraper device according to a preferred embodiment of the present invention;
(13) FIG. 12 is an elevated perspective view of the carriage assembly of the firetube scraper device according to a preferred embodiment of the present invention;
(14) FIG. 13 is a perspective view of the mounting brackets for the carriage assembly according to a preferred embodiment of the present invention;
(15) FIG. 14 is a perspective view of the desanding line used with the firetube scraper according to a preferred embodiment of the present invention;
(16) FIG. 15 is a front view of a scraper fin according to a preferred embodiment of the present invention;
(17) FIG. 16 is a back view of a scraper fin according to a preferred embodiment of the present invention;
(18) FIG. 17 is a side view of a scraper fin according to a preferred embodiment of the present invention; and
(19) FIG. 18 is a perspective view of a scraper fin according to a preferred embodiment of the present invention.
(20) FIG. 19 is a cropped cross-sectional view of the firetube showing the carriage member according to a preferred embodiment of the present invention.
(21) FIG. 20 is a close up perspective view of the firetube showing the carriage member according to a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
(22) FIGS. 1 and 2 show the firetube scraper device (1) according to a preferred embodiment of the present invention. The firetube scraper is intended to be used on the external surface of the tube (2) where polymers and other solids deposits under exposure to the high heat of the firetube. The deposition of the solids on the firetube leads to both a loss of effectiveness and eventual tube failure which is both costly and time intensive to replace. According to the preferred embodiment depicted in FIGS. 1 and 2, a desanding line (3) is located substantially above and parallel to the drive line (5).
(23) According to the preferred embodiment illustrated in FIGS. 1 and 2, the firetube scraper is designed to be fitted around a firetube and to move longitudinally along the tube through the use of a screw drive mechanism. The screw drive is the preferred embodiment of the drive system, other drive mechanisms, such as hydraulic or pulley could function as another embodiment of the drive mechanism. A plurality of scraping tools affixed on the scraper around the circumference of the tube are in frictional contact with the surface of the tube and move along the surface thereof through the action of a screw drive mechanism. FIG. 1 shows a firetube and the scraper located at five different positions on the tube. FIG. 2 is a close up of the scraper showing the frame holding a plurality of scrapers (shoes) located in such a manner as to cover the entire circumference of the firetube.
(24) As shown in FIG. 14, the desanding line (3) comprises a spraying system (7) adapted to spray a liquid onto the carriage assembly (9). The liquid is sprayed through a plurality of nozzles (11) positioned along a branch (13) substantially perpendicular to the desanding line (3). Preferably, the branch (13) has a slight outward curvature in order to have the liquid spray over a larger area of the carriage assembly (9). The liquid is discharged through the nozzles (11) at a velocity sufficient to reach the carriage assembly (9) and remove the particulates that have been removed by the scrapper fins (43). This has several advantages. First, it increases the life expectancy of the scraper fins as these wear out when rubbing the solid particulates contained in the liquid against the firetube. Prompt removal of these particulates through the use of the desanding line allows to minimize the time of contact between the scraper fins, the sand and the firetube. A second advantage is to make the scraping action more efficient as buildup is avoided or at least minimized thus facilitating the work of the scraper fins.
(25) FIGS. 19 and 20 show an alternative embodiment of the desanding line where it is centrally mounted between the top section and the bottom section of the firetube. In this embodiment, the arms of the spraying system (7) of the desanding line (3) adopt the curvature of the bottom section of the firetube.
(26) Drive Line
(27) The embodiments shown in FIGS. 1 to 3 show a firetube scraper having 5 carriage assemblies (9) disposed along the length of the bottom tubing (2a). Each carriage assembly (9) is adapted to move longitudinally along the firetube and scrape a predetermined section thereof. The carriage assemblies are attached to the drive line (5) through supports (7) located on the main overhead carriage member (19). The drive line is itself installed on the firetube by installing a support member wedged in between the bottom (2a) and top (2b) tube sections. The drive line (5) comprises a gearbox mount which itself comprises the screw assembly to move the moving frame (25) along the drive line (5). The moving frame (25) comprises the mounting brackets (27) to mount each carriage assembly onto the drive line (5). The mounting brackets can be more clearly seen in FIG. 13. The mounting brackets comprise an upper section (29) and a lower section (31) bolted together through the use of four hexagonal screws (33). The lower section of the mounting brackets comprises a channel (35) in which the mounting support (41) is inserted during assembly and subsequently the lower and upper sections are fastened together with the screws (33). Preferably, each carriage assembly has at least one mounting bracket, more preferably they have two or more.
(28) FIGS. 4 through 7 depict the drive line (5) and the various components making up the inner workings thereof. More specifically, FIG. 4 depicts the internals of the drive system. Present on the moving frame (25) of the drive line (5) is a series of various types of seals intended on eliminating the potential for leaks into the drive line. The relative simplicity of the movement (simply longitudinal) of the drive line is intended on minimizing the possible breakdowns of the moving parts of this device.
(29) FIG. 4 shows a close up of the drive rod assembly. The thrust flange (101) is secured to the thrust flange cap (103) with socket head cap screws (113). The gearbox mount is fastened to the thrust flange (101), thrust flange cap (103) and vessel nozzle with stud bolts (109) and hex nuts (110). A dowel pin (106) secures the thrust washers (127) and washer spacers (126) inside the thrust flange (101) and thrust flange cap (103). An O-ring (108) seals the thrust flange (101) and the flange cap (103). Gasket (111) seals the thrust flange (101) to the vessel nozzle on the opposite side of the gearbox mount. Socket head cap screws (112) secure together a wiper seal, shaft seal, O-ring (129), and seal retainer ring (122) providing a seal between the thrust flange cap (103) and quill shaft (121). A speedi sleeve is installed on quill shaft (121) and is a replaceable sealing surface that wears as quill shaft (121) rotates relative to shaft seal and wiper seal. Shaft seal is the primary seal for the assembly. Seal gland (117) secures the primary seal (114) and primary wiper (107) to the thrust flange by means of socket head cap screws (112). Primary seal (114) and primary wiper (107) seal the quill shaft (121) to the thrust flange (101). A speedi sleeve is installed on quill shaft (121) and is a replaceable sealing surface that wears as the quill shaft (121) rotates relative to the primary shaft seal and primary wiper seal. An adapter (118) is located at the end of the shaft quill (121) and surround the latter's end. Adapter (118) converts the splined end connection of the quill shaft (121) to a suitable bore for connecting to the prime mover and/or gearbox (102). The quill shaft (121) is in rotational contact with bearings (119) and (120). All radial loads on quill shaft (121) are resolved through bearings (119) and (120). The thrust nut (123) and bearing nut (124) work in combination to resolve the thrust loads from the system. The bearing nut (124) is locked in place with set screws (133). The thrust nut (123) is in rotational contact with the thrust washers (127). Another spacer washer (126) is abutted against one side of the thrust nut (123) of the beta drive while a thrust washer (127) is abutted against the other side.
(30) The coupling mechanism of the beta drive system includes a drive coupling (130), an hexagonal bolt (131) and nut (132).
(31) FIG. 3 is a close-up view of the carriage assembly (9) and the spraying system (7) located above each carriage assembly (9) and adapted to spray the carriage as the latter moves back and forth during operation to clean the scraper fins.
(32) FIGS. 8-12 show the carriage assembly of the firetube scraper device according to the embodiment of FIGS. 1-3. FIGS. 8 and 11 show the placement of the scraper fins to show the staggering of scraper fins (43) on each subsequent row of fins to ensure proper scraping of the external surface of the firetube (2).
(33) Carriage Assembly
(34) According to a preferred embodiment of the present invention as depicted in FIGS. 8 to 12, the carriage assembly comprises: a main overhead carriage member (19) operationally connected to the drive line (5) through support (41); and two pairs of clamp arms (45) and (45a), each clamp arm (45) having two extremities (47) and (47a); wherein each one of said clamp arm having a first extremity (47) hingedly connected to the main overhead carriage member (19) and a second extremity (47a) connected to a second extremity of the opposite clamp arm by fastening means. Preferably, the main overhead carriage member (19) is a weldment. A weldment is a unit composed of an assemblage of pieces welded together. The mounting supports (41) adapted to be mounted on the mounting brackets (27) located on the moving frame 25 of the drive line (5) are preferably mounted on the main overhead carriage member (19).
(35) Scraper Fins
(36) FIGS. 15 to 18 illustrate the scraper fins according to a preferred embodiment of the present invention. Each scraper fin (43) has a front side (61) and a backside (63), the front side (61) having a curvature adapted to frictionally contact the external surface of the firetube. According to a preferred embodiment, the backside of a scraper fin comprises a plurality of projections substantially perpendicular to the backside. More preferably, the backside (63) comprising fastening means attachment points (65, 65a, 65b) positioned on the projections for securing the scraper fin (43) to the carriage assembly (9). Also more preferably, the backside comprising at least one lateral aperture located on a projection, said aperture adapted to receive a scraper fastening means (69).
(37) According to the illustrated embodiment, the scraper fastening means is a rod (69) adapted to be inserted through an aperture located on the clamp arm and through the aperture located in the projection of the scraper fin.
(38) Preferably, the rod will be inserted through an aperture located proximate the middle of the back side (63) of a scraper fin located on a first row and through an aperture located proximate one extremity of the backside of a scraper fin located on the subsequent row.
(39) According to a more preferred embodiment, the rod (69) will be inserted through an aperture located in the middle of the backside of a scraper fin on a first row and the apertures located on the adjoining extremities of the backside of neighboring scraper fins located on the subsequent row. Ideally, the backside of the scraper has a total of at least three apertures adapted to receive rods therethrough to secure the scraper fins to the carriage assembly. The backside will define a longitudinal axis (71) preferably located in the middle thereof. Along this axis (71) are positioned a central aperture and an aperture located at a first extremity and an aperture located at the opposite extremity. Preferably, to allow more efficient placement of scraper fins (43) along a row, the apertures located at the first and second extremity are offset to one another with respect to the axis so as to allow staggering of the apertures from subsequent scraper fins and thus provide additional stability to each fin.
(40) Preferably, each scraper fin has a central projection on its back side extending beyond the surface defined by the front side and adapted to abut on one end against the aperture located at one extremity of the backside of a scraper fin located on the subsequent row and at the opposite end against the clamp arm. Preferably also, the projections located at each extremity of the scraper fins also extend beyond the plane defined by the front surface so as to allow for a hinge connection with the extremity of the adjoining scraper fin.
(41) Each rod (69) adapted to be inserted into the lateral apertures located on the projections (75) on the backside of the scraper fins (43) and fastened at both extremities (71a)(71b) to a clamp arm (45).
(42) The pair of clamp arms (45 and 45a) are fastened to one another at their second extremity (47a) so as to surround the circumference of the firetube (2) further comprising a spring retainer (77) to maintain the clamp arms (45 and 45a) in proximate position around the firetube allowing frictional contact onto the external surface of the firetube by the scraper fins.
(43) The embodiments described herein are to be understood to be exemplary and numerous modification and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the claims appended hereto, the invention may be practiced otherwise than as specifically disclosed herein.
