Abstract:
An apparatus for cleaning the interior of a vessel for containing a sanitary product by ejecting a rotating stream of cleaning fluid. The apparatus features a stationary housing that forms an inlet for receiving a flow of cleaning fluid, a rotatable housing mounted for rotation on the stationary housing about a first axis, and a nozzle for ejecting the cleaning fluid, the nozzle being rotatably mounted on the rotatable housing so that the nozzle rotates about a second axis. A planetary gear train is driven by an impeller driven by the flow of cleaning fluid and drives the rotation of the rotatable housing. The planetary gear train is located between the apparatus inlet and the nozzle. A portion of the flow of cleaning fluid received by the inlet is diverted so as to flow through a passage through the planetary gear train so that the planetary gear train is cooled and lubricated without the use of oil-based or other lubricants unsuitable for contact with sanitary products that might contaminate the cleaning fluid.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to an apparatus and method for cleaning vessels, such as tanks and barrels, using a pressurized fluid stream. More specifically, the present invention relates to a vessel cleaning apparatus and method that is especially well suited to cleaning vessels that cannot be contaminated with oil or other lubricants, such as a vessel used for processing sanitary products.  
         BACKGROUND OF THE INVENTION  
         [0002]    Vessels, such as tanks, are frequently cleaned by inserting a cleaning machine, which is supplied with heated, pressurized cleaning fluid, through a access port in the vessel. The cleaning machine ejects the cleaning fluid as a high velocity jet that scours the inside walls of the tank so as to effect a cleaning action. In order to obtain as wide a coverage as possible, such cleaning apparatus frequently employ rotating nozzles that sweep around as they eject the cleaning fluid. Cleaning apparatus sold by Gamajet Cleaning Services, Inc., assignee of the current invention, achieve almost 360° coverage by rotating the nozzles around two mutually perpendicular axes. In such apparatus, the rotation of the nozzles is driven by a gear train that is, in turn, driven by the incoming flow of cleaning fluid via an impeller connected to the drive shaft for the gear train. Consequently, such apparatus are sometimes referred to as fluid powered, gear driven tank cleaning machines.  
           [0003]    One early version of a fluid powered, gear driven tank cleaning machine, known commercially as the Gamajet III, is shown in U.S. Pat. No. 3,637,138 (Rucker). In the late 1980&#39;s, Gamajet introduced the Gamajet IV cleaning machine, shown in U.S. Pat. No. 5,012,976 (Loberg), which had a relatively large maximum flow rate of 300 GPM. Like the Gamajet III, the Gamajet IV featured a gear train that comprised numerous stages of pinion and spurs gears that ultimately drove a ring gear fixed on a rotating T-housing assembly so as to cause rotation of the nozzles assembly about the first axis. A bevel gear fixed on the nozzle assembly mated with a bevel gear fixed on a stem housing, which remains stationary, so that rotation of the nozzle assembly about the first axis caused rotation of the nozzles about the second axis. The fluid inlet was formed at one end of the machine, while the gear train was disposed at the other end of the machine. The rotating nozzle assembly was disposed between the inlet and the gear train. The gear train was lubricated by the cleaning fluid flowing through the machine.  
           [0004]    In order to enable the impeller to operate at an efficient speed without causing the nozzles to spin too quickly, which can result in the production of a mist rather than a strong jet, the gear trains of fluid powered, gear driven tank cleaning machines must be capable of high speed reduction. In both the Gamajet III and IV, this high speed reduction was achieved by means of a number of successive stages of spur and pinion gears. In each stage, a small input pinion gear turns a large output spur gear, thereby causing an incremental speed reduction. The output spur gear of that stage is connected to a small input pinon gear of the next stage, and so on. Unfortunately, this approach results in a relatively large gear train. Thus, the gear box of the Gamajet IV is over four inches in diameter. When combined with the nozzle housing, the width of the machine is about 6 inches so that the minimum entry opening for the machine is over 6 inches. Consequently, such machines cannot be used in some applications, such as small tanks, which feature relatively small entry ports. Moreover, Gamajet IV machines were relatively heavy, approximately 30 lbs, making their manipulation during installation and use difficult.  
           [0005]    In 1994, Gamajet introduced the Gamajet V tank cleaning machine, which is shown in U.S. Pat. No. 5,954,271 (Minh et al.). As a result of its configuration, the gear train of the Gamajet V is housed in a gear box having a diameter of only approximately 2 inches. This is only one-half the diameter of the Gamajet IV gearbox. As a result of the reduced size of the gear box, together with the use of a compact nozzle housing, the Gamajet V can be easily inserted into a 3 inch diameter access port. In addition, the Gamajet V is relatively light weight, weighing only about 7 lbs. The gear train of the Gamajet V featured three stages of gears rotating within a rotating cylindrical ring gear. The first and second stages are planetary gears, while the third stage are stationary gears. A first pinion gear, which is driven by the impeller shaft, drives the first stage of planetary gears. The first stage of planetary gears drives a second pinion gear that then drives the second stage of planetary gears. The second stage of planetary gears drives a third pinion gear that then drives the stationary third stage of gears. The stationary gears of the third stage drive the cylindrical ring gear. The cylindrical ring gear drives a pinion gear that, via idler gears, drives the ring gear that rotates the nozzle assembly. As in the Gamajet IV, the fluid inlet of the Gamajet V was formed at one end of the machine, the gear train was disposed at the other end of the machine, and the rotating nozzle assembly was disposed between the inlet and the gear train. The planetary gear train is lubricated by grease and mounted in a sealed housing to minimize contamination of the cleaning fluid by the grease. Nevertheless, gear box leakage can still occur if the seals are compromised. Still later, Gamajet developed a tank cleaning machine, which is shown in U.S. Pat. No. 6,123,271 (Delaney et al.), hereby incorporated by reference in its entirety, that located the planetary gear train between the inlet and the rotating outlet nozzles and improved the sealing of the gear train.  
           [0006]    Despite the improvements in gear train sealing, the possibility of contamination of the cleaning fluid, and consequently the vessel being cleaned, with lubricants used within the gear train have limited the use of such cleaning machines in vessels used to process sanitary products in which lubricant contamination cannot be tolerated, such as food, beverages, pharmaceuticals, and personal care products such as shampoo. Consequently, in the past, vessels used for sanitary products that would otherwise have been ideal candidates for cleaning by compact planetary gear driven tank cleaning machines have instead been cleaned by machines that did not require gear trains and, consequently did not require lubrication, such as a non-rotating ball type cleaning apparatus, with numerous discharge nozzles formed about the circumference of a ball. However, such non-rotating apparatus cannot clean as effectively as the planetary gear train driven cleaning machines discussed above.  
           [0007]    Consequently, it would be desirable developed a planetary gear driven tank cleaning machine that did not require the use of any lubricants, including lubricants in the planetary gear train, that might contaminate the cleaning fluid.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of the current invention to provide an improved cleaning machine for cleaning the inside of vessels. This and other objects are achieved in an apparatus for cleaning the interior of a vessel by ejecting a rotating stream of cleaning fluid, comprising (i) a first fluid inlet for receiving the cleaning fluid, (ii) a rotatable housing mounted for rotation about a first axis, (iii) a nozzle having a first fluid outlet for ejecting the cleaning fluid received by the first fluid inlet, the nozzle rotatably mounted on the rotatable housing so that the nozzle rotates about a second axis, a first fluid passage placing the first fluid inlet in fluid flow communication with the first fluid outlet, (iv) an input shaft driven by the fluid received by the first fluid inlet, (v) a planetary gear train comprising a sun gear and at least one planetary gear mounted for rotation about the sun gear, the planetary gear train driven by the input shaft, the planetary gear train driving the rotatable housing to rotate about the first axis, (vi) a housing at least partially enclosing the planetary gear train, a second fluid passage formed within the housing, the sun gear and the planetary gear disposed within the second fluid passage, the second fluid passage having a second fluid(inlet and a second fluid outlet that together place the second fluid passage in flow communication with the first fluid passage, wherein at least a portion of the cleaning fluid received by the first fluid inlet flows through a portion of the first fluid passage and then flows into the second fluid inlet and then flows through the second fluid passage so as to flow over the sun gear and the planetary gear and then flows through the second fluid outlet so as to reenter the first fluid passage and then flows through the first fluid outlet.  
           [0009]    The current invention also encompasses a method of cleaning a vessel suitable for containing a sanitary product, comprising the steps of (i) introducing a cleaning machine into the vessel, (ii) introducing a flow of cleaning fluid into an inlet of the cleaning machine, (iii) rotating an impeller by directing the cleaning fluid to flow over the impeller so that the impeller drives rotation of a planetary gear train, the planetary gear train driving rotation of a rotatable body housing about a first axis, the rotatable body housing driving rotation of a rotatable nozzle housing about a second axis, (v) directing the flow of cleaning fluid received by the inlet through a passage to a nozzle mounted on the rotatable nozzle housing so that the nozzle rotates with the rotatable nozzle housing, (vi) ejecting the cleaning fluid from the nozzle, (vii) cooling and lubricating the planetary gear train by diverting a portion of the flow of cleaning fluid from the passage so as to cause the portion of the cleaning fluid to flow through the planetary gear train and then reintroducing the portion of the cleaning fluid back into the passage so that the reintroduced portion of the cleaning fluid is then ejected from the nozzle 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is an isometric view of a vessel cleaning machine according to the current invention.  
         [0011]    [0011]FIG. 2 is a longitudinal cross-section of the cleaning machine shown in FIG. 1 taken along line II-II shown in FIG. 1.  
         [0012]    [0012]FIG. 3 is an exploded view of the cleaning machine shown in FIG. 1.  
         [0013]    [0013]FIG. 4 is an isometric view of the drive train of the cleaning machine shown in FIG. 1.  
         [0014]    [0014]FIG. 5 is an exploded view of the planetary gear train portion of the drive train assembly shown in FIG. 4.  
         [0015]    [0015]FIG. 6 is an isometric view, partially cut away, of the planetary gear train portion of the drive train assembly shown in FIG. 4.  
         [0016]    [0016]FIG. 7 is a detailed longitudinal cross-section of the planetary gear train shown in FIG. 6.  
         [0017]    [0017]FIG. 7( a ) is a view similar to FIG. 7 but with the planetary gears deleted from the upper half of the cross-section to better illustrate the flow path of cleaning fluid through the planetary gear train.  
         [0018]    [0018]FIG. 8 is a transverse cross-section through the planetary gear train shown in FIG. 7 taken along line VIII-VIII.  
         [0019]    [0019]FIG. 9 is a transverse cross-section through the planetary gear train shown in FIG. 7 taken along line IX-IX.  
         [0020]    [0020]FIG. 10 is a transverse cross-section through rear bearing housing taken along line X-X shown in FIG. 7.  
         [0021]    [0021]FIG. 11 is a transverse cross-section through the gearing for the T-housing taken along line M-XI shown in FIG. 2. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]    A vessel cleaning machine  1  according to the current invention is shown in FIG. 1. The cleaning machine  1  is primarily comprised of a stationary structure and a rotating structure. As shown in FIGS. 1 and 2, the stationary structure is comprised of an inlet housing  2 , an upper stem  4  and a base  6 . An inlet  14  is formed within the inlet housing  2  and forms one end of the machine. The other end of the machine is formed by the base  6 . The rotating structure is comprised of a rotating T-housing  8  and a nozzle housing  10  mounted on the T-housing. Preferably, three spray nozzles  12  are mounted on the nozzle housing  10 .  
         [0023]    In operation, pressurized cleaning fluid  3  is supplied to the machine inlet  14 , for example via a hose threaded into the inlet housing  2 . When the apparatus is used to clean a vessel intended for sanitary products, the cleaning fluid is typically water, which may be at ambient temperature or may be heated to a temperature as high as about 190° F. As discussed more fully below, the fluid  3  drives gearing that causes the T-housing  8 , including the nozzle housing  10 , to rotate about axis A 1  and causes the nozzle housing to rotate about axis A 2 , which is preferably perpendicular to axis A 1 . Eventually, the cleaning fluid  7  is ejected from the spray nozzles  12 . Since the nozzles rotate about both axes A 1  and A 2 , the spray pattern they produce provides essentially 360° coverage so as to provide effective cleaning of the vessel walls.  
         [0024]    FIGS.  3 - 11  show the cleaning machine  1  in more detail. The inlet housing  2  is threaded onto the cap  22  of the upper stem  4  and secured by means of a set screw  20 . The stem cap  22  is attached by screws  26  to the upper stem  4 . The T-housing  8  is mounted on front and rear bearings  52  and  54 , respectively. The bearings  52  and  54  are mounted on a stem  87  that is mounted to the upper stem  4  by means of screws  89 .  
         [0025]    This arrangement enables the T-housing  8  to rotate about the centerline of the upper stem  4  and stem  87 , which forms the axis A 1 .  
         [0026]    A swirler  16 , is mounted within the stem cap  22  and serves to pre-swirl the incoming stream of pressurized cleaning fluid  3 . As discussed in aforementioned U.S. Pat. No. 6,123,271, the swirler  16  preferably comprises a disc-shaped body having a number of passages  17 . The passages  17  are oriented at an acute angle with respect to the axis A 1  that, preferably, is no more than about 30°. The passages  17  swirl the cleaning fluid  3  before it reaches the impeller  18 . Alternatively, a stationary vane type swirler could also be used.  
         [0027]    After exiting the swirler  16 , the cleaning fluid flows over an impeller  18 , to which it imparts sufficient torque to rotate an input drive shaft  76  on which the impeller is mounted. The input drive shaft  76  is supported by a front bearing housing  28  in which a bearing containing a tungsten carbide sleeve  66  is press mounted. An input pinion gear  78  mounted on the end of the input drive shaft  76  drives a planetary gear train  5 .  
         [0028]    The planetary gear train  5  is enclosed within a housing formed by the front bearing housing  28 , a cylindrical ring gear  44 , and a rear bearing housing  34 . As shown in detail in FIGS.  6 - 9 , the planetary train  5  is comprised of four stages of planetary gearing, one of which is shown in FIG. 9, and each of which includes three planetary gears  97  that are driven by a sun gear. The sun gear for the first planetary gear stage is formed by the input pinion gear  78  and for the three succeeding stages by gears  93 . The sun gears  93  are each affixed to the rear face of a support member  77 . The planetary gears are mounted on three shafts that project from the front face of each of the support members  77 . Preferably, each planetary gear  97  has a bushing made from carbon filled polyphenylene sulfide. Washers  75  and  79  are disposed on either side of the planetary gears  97 . As shown best in FIG. 9, each stage of planetary gears  97  rotate within a cylindrical ring gear  44  having teeth  91  formed on its inside diameter, which causes rotation of the support member  77 . The rotation of the support member  77  drives the sun gear  93  of the next stage. The last support member, which is part of the planetary gear train output shaft  80 , is connected to an output drive shaft  36 , as shown in FIG. 2. Preferably, the speed reduction achieved by the planetary gear train  5  is at least about 250:1, and in one embodiment of the invention is 256:1.  
         [0029]    The front end of the output drive shaft  36  is supported by the rear bearing housing  34 . An output pinion gear  38  is mounted on the end of the output drive shaft  36 . As shown best in FIGS. 4 and 11, the output pinion gear  38  drives two idler gears  58  that are supported by shafts  60 . The idler gears  58  are not planetary gears and do note rotate about the A 1  axis. The shafts  60  extend between an idler shaft base  92  and the base  6 . The idler shaft base  92  is secured to the stem  87  by screws  55 , while the base  6  is secured to the idler shaft base by means of screws  50 . As shown in FIG. 11, the idler gears  58  drive a ring gear  48 , retained in the T-housing  8 . The ring gear  48  is fixed to the T-housing  8  by means of a key  49  so that rotation of the ring gear  48  drives rotation of the T-housing.  
         [0030]    The gearing shown in FIG. 11 results in an additional speed reduction that is preferably at least about 3:1, and is more preferably about 3.33:1, so that, when combined with the planetary gear train  5 , the total gear reduction is at least about 750:1, and in one embodiment of the invention is about 850:1. Consequently, the speed of rotation of the T-housing  8  is reduced by a factor of at least about 750:1 compared to the speed of rotation of the impeller  18 . This arrangement allows the impeller  18  to turn at high speed in order to derive sufficient energy from the cleaning fluid  3  while allowing the nozzles  12  to turn at sufficiently low speed to effect proper cleaning.  
         [0031]    As shown in a FIG. 2, a stationary bevel gear  40  is attached to the stem  87 . The bevel gear  40  engages a bevel gear  42  fixed to the bottom of the nozzle housing  10 . Thus, rotation of the T-housing  8  about axis A 1  under the urging of the ring gear  48  and other gearing, shown in FIG. 4, causes the stationary bevel gear  40  to drive the bevel car  42 , thereby causing the nozzle housing  10  to rotate about its axis A 2 . The gear ratio between the bevel gears  40  and  42  is preferably slightly greater than 1 1 so that each 360° revolution of the T-housing  8  causes the nozzle housing  10  to rotate about 366° 
         [0032]    The flow path of the cleaning fluid  3  through the machine will now be discussed with reference to FIG. 2. After flowing over the swirler  16  and the impeller  18 , the fluid flows through an annular passage  30  The initial portions of the passage  30  are formed by an annular region created between the stem cap  22  and the front bearing housing  28  and then by a plurality of holes  31  formed within the front bearing housing  28 . The intermediate portions of the passage  30  are formed by an annular region created between the ring gear  44  and the upper stem  4  and then by holes  35  in the rear bearing housing  34 . The final portions of the passage  30  are formed first by an annular region created between the output drive shaft  36  and the stern  87 , then by four large openings  88  formed in the stem, then by a nose portion  51  of the T-housing  8 , and then by openings  57  in the nose From the openings  57  in the nose  51 , the cleaning fluid  7  flows radially outward through outlets formed in the noses  12   
         [0033]    As shown best in FIGS.  7 ( a ) to  9 , according to an important aspect of the current invention, a portion  3 ′ of the cleaning fluid, flowing axially through the portion of flow path  30  disposed in the upper stem  4 , is diverted into a series of radially oriented holes  41  formed in the ring gear  44 . From the inlet holes  41 , the cleaning fluid  3 ′ continues to flow radially inward to an annular inlet manifold  47  formed by a relief in the rear face of the front bearing housing  28  From the manifold  47 , the cleaning fluid  3 ′ flows axially along the valleys  43  formed between the teeth  91  on the inside diameter of the ring gear  44  and then into the space,  46  within the ring gear that is between the planetary gears  97  of the first stage of planetary gearing. The cleaning fluid  3 ′ then flows axially from stage to stage of the planetary gear train  5  by flowing through the valleys  43  in the ring gear teeth  91  and between the small radial gap between the planetary gear support members  77  or washers  79  and the ring gear teeth. After exiting the last stage of planetary gearing, the cleaning fluid  3 ′ flows into an annular outlet manifold  53  formed by a relief in the front face of the rear bearing housing  34 . From the outlet manifold  53 , the cleaning fluid  3 ′ is directed to a series of four axially oriented holes  45  extending through the rear bearing housing  34 . From the holes  45 , the now somewhat heated cleaning fluid  3 ′ flows axially so as to return to the passage  30 , specifically, the portion of the passage  30  formed between the stem  87  and the output drive shaft  36 .  
         [0034]    Note that since the inlet passages  41  and outlet passages  45  of the planetary gear train cooling flow path are located between the cleaning fluid inlet  14  and the discharge nozzles  12 , and the inlet passages  41  are disposed upstream of the outlet passages  45  with respect to the main cleaning fluid passage  30 , there is ample pressure drop available to ensure an adequate flow of cleaning fluid  3 ′ through the planetary gear train.  
         [0035]    Since the ring gear  44  is disposed within the intermediate portion of the passage  30 , cleaning fluid  3  flows over the ring gear so as to absorb a portion of the heat generated within the planetary gear train  5 . Moreover, by flowing directly through the planetary gear train  5  and over the planetary gears  97  and sun gears  78  and  93 , the diverted portion  3 ′ of the cleaning fluid cools and lubricates the planetary gear train  5 . Preferably, the amount of cooling and lubrication is sufficient so that oil-based lubricants, such as grease, or other lubricants considered to be contaminants with respect to sanitary products, such as lithium grease, need not be used in the planetary gear train  5 . Most preferably, no oil-based or other lubricants considered to be contaminants with respect to sanitary products would be used anywhere in the cleaning machine.  
         [0036]    In order to accommodate any reduction in lubrication and cooling associated with using cleaning fluid as essentially the exclusive cooling and lubrication medium, all of the components of the cleaning machine are preferably made of materials that will not rust or corrode when exposed to cleaning fluid. Most preferably, except for bushings and seals, the entire cleaning machine is made from stainless steel alloys. In one embodiment of the invention, the portions of the machine that are more highly loaded—such as the sun  78 ,  93  and planetary gears  97 , the shafting  36 ,  76 ,  80 , the planetary gear support members  77 , the ring gear  44 , etc.—are made from 17-4 PH stainless steel heat treated to H-900. Other, more lightly loaded components—such as the washers  75 ,  79 —are made from 316 stainless steel.  
         [0037]    The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.