Heat Exchanger Tube Reamer And Cleaning Apparatus

Abstract

This invention relates to tube cleaning apparatus for removing deposits such as scale or other foreign matter from the interior surfaces of the tubes of various sizes of boilers, condensers and other heat exchangers, and more particularly to improvements in such apparatus limiting whipping action of the cleaning shafts and utilizing fluid under pressure for controlling the cleaning shafts for cleaning purposes in a new and improved manner.

Description

BACKGROUND OF THE INVENTION

U.S. Pat. No. 2,803,842, issued Aug. 27, 1957, to Joseph C. Fuller is directed to a machine or apparatus for cleaning heat exchanger tubes or the like, of which this invention is an improvement thereover, limiting undue guess work on the part of the machine operator in the patented structure and consequent possible damage to the cleaning apparatus.

FIELD OF THE INVENTION

This invention is particularly directed to improvements in tube cleaning apparatus, similar to that disclosed in U.S. Pat. No. 2,803,842 mentioned above, which utilizes separately or in combination, hydraulic and pneumatic power to operate the functioning components of the machine in their proper sequence. Manual control of all functions of the apparatus by a single operator is possible by the simple manipulation of certain valves when required as visually indicated by a sudden change in pressure readings on a previously positioned pressure gauge. A traveling guide bearing surrounding the rotatable cleaning shaft within the cylinder of the machine is utilized to prevent severe vibrations or whipping of the cleaning shaft and the consequent wear or damage to the apparatus or tubes being cleaned.

SUMMARY OF THE INVENTION

In accordance with the invention claimed, a new and improved apparatus for cleaning boiler tubes is provided which provides operator controls for sensing tube penetration of the cleaning shaft as well as improvements in the use of the power actuating fluid for controlling the apparatus.

It is therefore the principle object of this invention to provide an improved tube cleaning machine or apparatus which may be quickly and easily positioned and aligned with respect to the tube about to be cleaned, and operated by one man to perform the cleaning function in a thorough, efficient manner, regardless of the overall length of the tube being cleaned.

Another object of this invention is to provide an improved tube cleaning apparatus which is capable of efficiently and economically performing its function by utilizing the specific properties of any liquid solvent under pressure, such as water, oil based liquid, or compressed air, either separately or in combination to accomplish the control and cleaning function of the apparatus.

A further object of this invention is to provide an improved tube cleaning machine or apparatus which consists of a single portable unit or assembly which may be readily positioned relative to the tubes being cleaned in either a horizontal or vertical position, with its rotatable cleaning shaft in alignment with the center of said tubes, and which may be easily and quickly disassembled and reassembled to repair or replace damaged or worn component parts.

A still further object of this invention is to provide an improved tube cleaning machine or apparatus having a traveling bearing means which is associated with the rotating cleaning shaft inside of the cylinder in which it rotates, which acts to prevent excessive vibration and wear of the various components caused by whipping of the shaft within the cylinder.

Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more readily described by reference to the accompanying drawings in which:

FIG. 1 is a top plan elevational view of the assembled tube cleaning machine or apparatus of this invention showing its reaming tool and cylinder in proper horizontal alignment with the center of one of several heat exchanger tubes about to be cleaned.

FIG. 2 is a right side elevational view of the assembled machine shown in FIG. 1, showing its reaming tool and cylinder in proper vertical alignment with the center of one of several heat exchanger tubes about to be cleaned.

FIG. 3 is an enlarged fragmentary vertical sectional view taken substantially on the line 3--3 of FIG. 1 illustrating in detail the principle components of the machine.

FIG. 4 is a fragmentary vertical sectional view taken on the lines 4--4 of FIGS. 1 and 3, through one of the pressure line support members, illustrating one method of locating and securing the support members in spaced relation on the main cylinder and one method of attaching a pressure gauge to one of the located support members.

FIG. 5 is a fragmentary vertical sectional view taken on the lines 5--5 of FIGS. 1 and 3 illustrating one method of utilizing a clamping means to locate and secure the intermediate support member to the cylinder and base support plate and to provide radial indentations in the cylinder at that location, and one means of closing the apertures in the gauge support extensions which are not in use.

FIG. 6 is a fragmentary horizontal sectional view through the four-way valve utilized to control the cleaning operation function of the machine, and is taken on the line 6--6 of FIG. 3.

FIG. 7 is an enlarged fragmentary vertical sectional view taken on the line 7--7 of FIG. 3 through the main cylinder and components of the traveling bearing member, illustrating one method of reducing the amount of pressure normally exerted on the front face of the bearing member.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the several views of the drawings for a more detailed description of the construction and other features of the invention by characters of reference, FIGS. 1, 2 and 3 illustrate the complete assembled tube reaming and cleaning machine or apparatus 10 of this invention which may be supported by the ground or floor of a building. For purposes of illustration, the apparatus is shown as mounted on a base plate 11. A main cylinder 12, which may be 10 to 20 feet or more in length depending on the length of tubes 13 to be cleaned, is supported in the upper header portions 14 and 15 of vertically extending brackets 16 and 17. These brackets are detachably mounted on the apparatus' supporting surface shown herein as base support plate 11 at the front and rear ends of the cylinder. Another vertically extending bracket 18 is located approximately mid-way between the ends of the cylinder and is detachably mounted on base support plate 20. The upper end of bracket 18 is provided with the lower portion 19' of an integral clamping member 19. Clamping member 19 is adapted to support and secure the cylinder at this location when the upper portion 19" of the clamping member 19 is secured to the lower portion 19' by means of bolts 20.

The upper portion 19" of the clamping member 19 is preferably formed integrally with or welded to a vertical support member or extension 21. Extension 21 may be formed of a piece of steel pipe or cast integrally with or connected to a hollow cylindrical horizontal extension 22 at its upper end. Extension 22 is adapted to receive and support a pressure line 23, as shown in FIGS. 2 and 3. The vertical extension 21 is also provided with a lateral extending threaded boss 24 having a horizontal port 25 which communicates with a vertical port 26 in the extension 21 and a drilled aperture 27 in the top wall of cylinder 12. The threaded boss 24 is adapted to receive either a closure cap 28 or a pressure gauge 29 in full view of the operator of the machine.

The pressure line 23 is also supported by several additional vertical support members 30 having hollow horizontal ring like extensions 31 and 32, respectively, at their top and bottom ends. The diameters of their bores are sized to fit snugly but slidably with the outside peripheries of pressure line 23 and cylinder 12, so that they may be slid on or off of the pressure line and cylinder when desired. Thus, support members 30 may be located and secured in spaced relation on the cylinder 12 by means of set screws 33, as shown in FIG. 3.

It should be noted that the vertical support members 30 are similar in construction to the vertical support member 21 previously described, in that they are each provided with lateral extending threaded bosses 24' having horizontal ports 25' which communicate with the vertical ports 26' and the apertures 27' in the top wall of the cylinder 12. Their threaded bosses 24' are adapted to receive either a closure cap 28 or support the pressure gage 29, in full view of the machine operator.

The several apertures 27 and 27' are drilled in and spaced longitudinally of cylinder 12 in its top arcuate wall at specific intervals or distances which correspond with the required longitudinal movement of a cleaning rod and piston assembly 34 arranged within cylinder 12 in order to accomplish the reaming and cleaning of any specific length of tube, such as for instance a 4, 6, 8, 10, 12, 14, 16, 18 and 20 foot length or longer depending on the length of cylinder 12, as clearly indicated in FIG. 2. The vertical support members 21 and 30 are thus positioned and secured on cylinder 12 to provide direct communication between the vertical ports 26 and 26' in the support members and the apertures 27 and 27' in the top wall of the cylinder and hence with the inside bore 35 of cylinder 12.

The rear end portion 23' of pressure line 23 is curved downwardly and secured in leak proof relation to the top of the header portion 14 of the rear vertical bracket 16 in such a manner that its interior bore communicates with a vertical port 36 in the header and with a counter-bore 37 in the front face of the header. The header is also provided with an annular groove 38 which is adapted to receive the rear end of cylinder 12 and a combination sealing ring and bumper 39. Bumper 39 is preferably made of rubber to seal and firmly support the rear end of cylinder 12. The upper forward end of the pressure line portion 23' is connected to line 23 by means of a coupling or union 40.

The forward end of pressure line 23 is connected in sealed relation to the rear face of a four way valve 41, the outer body 41' of which is preferably square in shape and mounted between a pair of upwardly extending brackets 42. Brackets 42 may be formed integral with the top surface of portion 15.

A discharge line 43 is connected to the front face of the four-way valve body 41' and is connected to the center outlet of a T-fitting 44. T-fitting 44 has a right angle extension 43' which projects downward and rearwardly from its lower outlet where it is connected to a right angle fitting 45. Fitting 45 is mounted in the top surface of header portion 15 of the vertical bracket 17, thus providing communication between a port in the front side of the four-way valve body 41' and a vertical port 46 in portion 15 of bracket 17. A counter bore 47 in the rear face of header portion 15 is open to the inside bore 35 of cylinder 12. The rear face of header portion 15 is provided with a concentric annular groove 48 which is adapted to receive the front end of cylinder 12, and a combination sealing ring and bumber 49 made of rubber mounted therein seals and firmly supports the front end of cylinder 12.

The rear header portion 14 is provided with a detachable cover plate 50 and a sealing gasket 51 which are adapted to provide a closure means and access to a clean-out opening 52 into the counter bore 37 in the rear face of the header portion. The front header portion 15 is also provided with a detachable cover plate 53 and a sealing gasket 54. The cover plate has a forwardly projecting threaded extension 55 which is provided with a central bore 56 concentric with the center line 57 of the inside bore 35 of cylinder 12. This bore communicates with a similar bore 58 and counter bore 47 in header portion 15. The bores 56 and 58 have diameters which are just slightly greater than the diagonal measurement of the square shaped hollow cleaning rod 34' and provide suitable bearing surfaces for the reciprocating and rotating cleaning rod 34' extending therethrough.

A pair of vertically mounted spaced support members or plates 59 and 60 are shown as being secured to the base plate 11. The inside faces of these vertical plates are utilized to provide thrust bearing surfaces for a driving hub 61 and a driven hub 62. Each hub has attached thereto pulleys 63 and 64, respectively. A continuous V-belt 65 mounted thereon provides the driving means for rotating hub 62 and cleaning rod 34' in unison, but at the same time allows reciprocation of the cleaning rod in the hub through an aperture 62' in the center of the hub.

The driven hub 62 is provided at its front end with an inside threaded bore 71 and a counter bore 72 through the center of which the square cleaning rod 34' extends. The threaded bore 71 is adapted to receive an outside threaded male plug or gland nut 73 having an aperture 74 through which the cleaning rod extends a short distance. The counter bore 72 is filled with suitable packing material which is compressed and packed tightly around the sides of the cleaning rod 34' when the male plug or gland nut 73 is screwed into the threaded bore 71, thus preventing leakage of pressurized liquid or air from around the sides of the cleaning rod when the same is rotated and reciprocated.

The outer ends of hub 62 are adapted to rotate on suitable bearing members 59' and 60' mounted in the opposed inside faces of the vertical support plates 59 and 60, respectively. Hub 62 is restricted in lateral movement by the inside faces of the plates between which the end faces of hub 62 are retained. The rear face of hub 62 is also provided with a counter bore 72' which is filled with suitable packing material around cleaning rod 34' to further prevent leakage of pressurized liquid or air.

The rear face of the vertical support plate 59 is provided with an outside threaded extension 75 which projects rearwardly in horizontal and vertical alignment with the outside threaded extension 55 on the front cover plate 53. Extension 75 is provided with a central bore 76 which is slightly larger in diameter than the diagonal dimension of the square cleaning rod 34' which rotages and reciprocates therein. The threaded extensions 55 and 75 are detachably joined together in rigid, leak-proof relationship by a suitable coupling or union 77.

The propulsion means utilized to provide the necessary motive force to operate the drive train elements previously described, preferably comprises an air motor 66 which receives its power from a source of compressed air, such as an air compressor (not shown), through a flexible hose 67 and a T-fitting 68. Motor 66 rotates the driving hub 61 and its pulley 63 through their central shaft and the shaft of the air motor which are detachably coupled together at 69 as shown in FIGS. 1 and 2. Vertical support plates 59 and 60 are held in spaced relation by a tie plate 70, which is removably secured to the top end surfaces of the plates to increase the rigidity of the structure and to protect the machine operator's hands from sustaining injury from the moving parts.

The body portion 41' of the four-way valve 41 is provided with four ports 78, 79, 80 and 81, all of which are in the same horizontal plane. Two of the ports, namely, 78 and 80, are opposed longitudinally and the other two ports 79 and 81 are opposed in a lateral plane, as shown in FIGS. 3 and 6. Ports 78 and 79 normally communicate with an arcuate passage 82 in valve 41 and ports 80 and 81 normally communicate with an arcuate passage 83 in valve 41. All ports and passages are in the same horizontal plane with the passages being formed in a rotatable cylindrical core 84 which is secured in the bore of the valve body 41' by any suitable means, such as a retaining washer 85 and a nut 86. Nut 86 is threaded onto a downwardly projecting stud extending from the bottom surface of the cylindrical core 84.

The port 78 in the valve body 41' communicates with the front end of pressure line 23, and port 80 communicates with the discharge line 43, as previously mentioned. Ports 79 and 80 communicate with a flexible feed hose 87 and a flexible discharge hose 88, respectively, which are secured in leak-proof relation on the left and right sides of the valve body. Feed hose 87 is adapted to carry any liquid cleaning solvent under pressure from any suitable source to the four-way valve 41, and the flexible discharge hose 88 is adapted to provide for passage of dispensed liquid into a storage tank or container (not shown) from which it may be reclaimed and used again. Hose 88 is also used to dispense pressurized or latent air to the atmosphere, as will be later explained.

The rotatable core 84 is provided at its upper end with an integral square extension 89, which projects upwardly through a clearance hole in the flat circular plate 90. Plate 90 is secured to and held in stationary relationship on the top end of the valve body 41' by welding, and its integral, smooth surfaced central boss provides a bearing surface for a flat surfaced operating or control lever 91. Control lever 91 is demountably attached to the projecting end of the square extension 89 by means of a square hole in lever 91 which fits snugly around the square extension, thereby allowing the machine operator to move the lever about an arc causing the four-way valve core 84 to be rotated to assume the desired port communicating position in the valve body 41' or an intermediate position which prevent communication between the ports. All of these positions are indicated by the letters "A," "B" and "C" shown in FIG. 6.

The operating or control lever 91 is provided on its flat upper surface with a suitable one-way air valve 92. This valve attached to lever 91 by screws or other suitable means has hose receiving projections extending from each of its ends. One extension is adapted to receive in clamped relationship one end of a flexible air hose 93. The other end of hose 93 is clamped to one side of the T-fitting 68 for receiving compressed air from the supply hose 67. Air valve 92 may be opened by a manually operated push button 94 located in the top of its valve housing.

The opposed opposite end projection from air valve 92 is adapted to receive in clamped relation one end of a comparatively short flexible air hose 95. The other end of hose 95 is secured in clamped relation to the top end of the T-fitting 44, as clearly shown in FIGS. 1 and 2 of the drawings. The specific function of air valve 92 and the respective flexible hoses 93 and 95 will be further explained as this description proceeds.

The main cylinder 12 may be fabricated of suitable metal or high impact strength plastic, having various inside diameters, depending on the need for utilizing liquid or air or a combination of both under pressures required for efficient functioning of the machine. The inside bore 35 of the cylinder should be smoothly surfaced or finished to allow for quick and easy reciprocation of the cleaning rod and piston assembly 34 within the cylinder.

The cleaning rod and piston assembly preferably consists of a square shaped, hollow cleaning rod 34' which is provided with a pair of small holes 96 at its extreme forward exposed end. Holes 96 communicates with the hollow interior of the rod 34', a traveling piston or bearing 97, which surrounds the rod and is normally positioned approximately mid-way in the bore of the cylinder, and a propulsion piston 98 which provides a suitable bearing for the hollow cylindrical rear end portion 99 of the rod 34'. Piston 98 is provided with an integrally mounted thrust washer 100 at its front end, which in turn is welded or otherwise secured to the extreme rear end of the cleaning rod 34'. The open end of the hollow cylindrical portion 99 of rod 34' is threaded to receive a thrust washer 101 and a pair of suitable lock nuts 102. Nuts 102 may be adjusted to limit the longitudinal movement of piston 98 between the thrust washers 100 and 101.

The cylindrical end portion 99 of rod 34' is adapted to rotate freely in a bearing sleeve member 103 which has been pressed into the central bore of piston 98. The outside diameter of sleeve member 103 is slightly less than the inside diameter of the main cylinder bore 35, and is provided with a pair of circumferential grooves which serve to retain a pair of "0"-rings 104, which are preferably made of neoprene rubber and sized to fit tightly in the bore 35 of the cylinder to prevent pressurized liquid or air passing from one side of the piston to the other. These "0"-rings are not tight enough to interfere with easy reciprocal movement of the piston and cleaning rod within the bore of the cylinder.

The traveling piston or guide bearing 97 is similar in size and shape to the propulsion piston 98, except that its outside diameter is considerably less than the inside diameter or bore 35 of the cylinder 12. A pair of "0"-rings 105 which are retained in similar circumferential grooves in the piston as in piston 98 are adapted to fit quite loosely in the cylinder bore to prevent excessive vibration of the piston or guide bearing 97 within bore 35 of cylinder 12 as it travels within the bore during a tube cleaning operation.

The traveling piston 97 serves as a guide bearing for the rotatable square cleaning rod 34' and provides a passage for pressurized liquid or air through the piston. To this end the piston is provided with a central bore 105 into which a hollow sleeve 106 extends. Sleeve 106 is provided with an integral enlarged circular rim or flange 107 at one end and an outside threaded portion at its other end. The threaded portion extends beyond the end face of the piston for retaining a sealing pressure cup 108, preferably made of flexible rubber, between the front face of the piston and a washer by means of a nut 109. Nut 109 may be tightened to secure the sleeve 106 and the sealing pressure cup 108 in place.

The inside diameter or bore 110 of the hollow sleeve 106 is just slightly larger than the diagonal dimension of the square cleaning rod 34' which it surrounds thereby providing a suitable bearing surface for contacting the rounded corners of the square rod as it rotates. The bore also provides four arcuate open sectors 111 around the flat outer walls of the cleaning rod through which pressurized liquid or air may pass at all times.

To complete the cleaning rod and piston assembly 34 it should be noted that the extreme forward exposed end of the cleaning rod 34' is provided with the usual carbide or tungsten tipped cleaning tool or bit 112 which may be secured to the end of the rod beyond the pair of small holes 96. The bit may be made in any size depending on the inside diameters of the heat exchanger or other tubes to be cleaned.

OPERATION OF APPARATUS

Having described in the preceding paragraphs the various features and construction of the components that make up the improved heat exhanger tube reaming and cleaning machine or apparatus, the operation of the machine or apparatus by a single attendant or operator will now be described.

It first should be understood that the machine is designed and can be operated to clean tubes of any given length, for example, from 4 to 20 feet, which distances may be indicated on the outside surface of the main cylinder 12 without causing the rotating cleaning rod 34' with its attached bit 112 to extend more than a few inches beyond the far end of the cleaned tube. This feature prevents severe damage to the cleaning rod by the stress and bending forces that would be applied to the out-board exposed end of the rotating cleaning rod should it be exposed beyond the far end of the cleaned tube more than a few inches.

With the machine positioned with its cylinder 12, cleaning rod 34' and cutting bit 112 in alignment with the center of, for example, a 4 foot tube to be cleaned, a pressure gauge 29 is threaded to a boss 24' on the indicated 4 foot vertical support member 30. Closure caps 28 are in place on all the other threaded bosses 24 and 24' along cylinder 12. The operator then activates air motor 66 causing compressed air to flow into the motor through the hose 67 from a source of air under pressure (not shown). This procedure causes the driving hub 61 and its pulley 63 to be rotated at a predetermined speed. Pulley 64 on the driven hub 62 is driven by V-belt 65 causing rotation of the square cleaning rod 34' with its associated cleaning tool or bit 112.

Cleaning rod 34' then rotated within bore 35 of cylinder 12, bearing sleeves 103 and 106 in the propulsion piston 98 and the traveling piston 97, bearing surfaces of the bore 58 in the header portion 15, bore 56 in the cover plate 53, and the threaded extension 55. The operator then opens the flexible feed line or hose 87 by actuating a quick action valve (not shown) to allow water, oil or any suitable liquid solvent to flow under pressure into the line. With the manual controls lever 91 in the position indicated by the letter "A" in FIG. 6, liquid under pressure flows through the arcuate passage 82 in the valve core, into the pressure line 23, through the vertical port 36 and into the counter bore 37 in the rear header 14. The liquid then flows through the hollow cylindrical rear end portion 99 and the square hollow center of the cleaning rod 34' to the pair of small holes 96 near the front end of the cleaning rod. The liquid is then ejected from rod 34' through holes 96 in the form of a spray to provide a flushing and lubricating action as the revolving cleaning bit 112 and cleaning rod 34' progresses through the tube being cleaned.

Coincident with the above described action, the pressurized liquid in the counter bore 37 exerts force on the rear face of the propulsion piston 98 causing this piston and the associated cleaning rod 34' to move forward in bore 35 of the cylinder. The traveling piston or bearing 97 remains substantially in the position shown in FIG. 3 of the drawings, thereby acting as a stabilizing element to prevent excessive vibration of the rotating cleaning rod 34'. Bearing 97 permits air or liquid which might be trapped in the cylinder bore 35, in front of piston 98 to be exhausted through the arcuate open longitudinal sectors 111 formed between the bore of the hollow sleeve 106 and the sides of the square rotating cleaning rod, counter bore 45, the vertical port 46 in the front header portion 15, angle fitting 45, pipe extension 43', T-fitting 44, discharge line or pipe 43 and the arcuate passage 83 in the four-way valve core 84, into and out of the discharge line or hose 88, to atmosphere or a reservoir (not shown).

As the propulsion piston 98 moves forward in bore 35 of the cylinder, the operator observes that the pressure reading on gauge 29 remains practically stable or at "0." As the piston continues its forward movement and passes slightly beyond the vertical communicating ports 26' in the vertical support member 30, and the port 27' in the top of the cylinder wall, which are located precisely at the 4 foot indication on the outer periphery of cylinder, the fluid under pressure forcing the piston and rod forward enters ports 27' and 26' and the horizontal port 25' in the threaded boss 24' on which the pressure gauge 29 is mounted, causing the gauge's pointer to suddenly indicate a higher pressure reading indicating to the operator that the cleaning rod has reached the end of the 4 foot stroke necessary to clean the particular tube 13 of that specific length.

When the operator observes this fact, he immediately moves the valve control lever 91, one-fourth of a turn, or 90.degree. to the position indicated by the letter "C" in FIG. 6. This action reverses the flow of pressurized liquid from the feed line or hose 87 through the core of the four-way valve into the discharge pipes 43 and 43', fitting 44 and 45, vertical port 46, counter bores 47 and 35 of the cylinder, through the arcuate longitudinal open sectors 111 in the traveling piston bearing 97 to the front face of the propulsion piston 98. The pressure on the front face of piston 98 causes this piston to be moved rearwardly to its starting position at the rear of the cylinder, simultaneously withdrawing the attached rotating cleaning rod and its cleaning tool or bit 112 from tube 13. The liquid which remains in bore 35 of cylinder 12 to the rear of piston 98 is forced back through the hollow cleaning rod and out the pair of small holes 96 as the cleaning rod is being withdrawn from the tube just cleaned. This liquid movement provides an additional flushing action in tube 13 to remove any particles of scale that may be left in the tube.

It should be evident from the above description of the operational features of the tube cleaning machine of the present invention, that tubes of any length, such as 12, 14, 16, 18, and 20 foot lengths may be cleaned thoroughly with equal efficiency and dispatch, and all the machine operator has to do when preparing to clean tubes that are, for example, 16 foot in length in a like manner, is to remove the pressure gauge 29 from its 4 foot indicator position and install the gauge on the threaded boss 24' of the 16 foot indicator position and to place a closure cap 28 on the 4 foot threaded boss. The operator then operates the cleaning machine in precisely the same manner as disclosed above.

When the machine is utilized to clean a 12 foot or longer tube, it should be noted and understood that the traveling piston or bearing 97 will be caused to move forward in the cylinder bore 35 from its normal intermediate position as shown in FIG. 3, by the force exerted on its rear face when contacted by the front end of the propulsion piston 98 in its forward travel necessary to clean the longer tube. On the return stroke of piston 98 and the consequent withdrawl of the cleaning rod 34' from the tube just cleaned, the traveling piston or bearing 97 with the rotating rod passes through it, must be returned to its normal intermediate position. The propulsion piston 98 also must be returned to its normal starting position at the rear end of the cylinder.

The above action is accomplished in the following manner: the pressure or force required for the return stroke of both pistons and the cleaning rod, is now exerted on the front area of the scaling pressure cup 108 which is attached to the traveling piston 97. This piston and the propulsion piston 98 are caused to move rearwardly by this force with piston 97 being stopped in its travel in bore 35 of the cylinder by means of a pair of arcuate projections 113 which extend slightly into bore 35. These projections have previously been formed therein by the drawing together of the two halves of the clamping member 19 at this intermediate point in the cylinder, as shown in FIG. 5 of the drawings. It is of course necessary that the propulsion piston 98 continues its rearward travel to the end of the cylinder bore. This is easily accomplished because the surface area of the sealing pressure cup 108 at the front of piston 97 is less than the surface area of the flat front end of piston 98. A portion of the pressurized liquid or air impinging in bore 35 by-passes cup 108 through the arcuate open sectors 111 between the walls of bore of the sleeve 106 and the sides of the square cleaning rod 34'. Thus, a greater pressure is exerted on the front face of piston 98 than piston 97 to cause it to continue its rearward travel. Should the differential in pressures at the front end of the pistons 97 and 98 not be sufficient to accomplish this result, piston 97 and the sealing pressure cup 108 could be provided with a plurality of small longitudinal holes 114, as shown in FIG. 7, to increase still further this differential of pressure.

After having completed the process of cleaning a particular tube by using a liquid under pressure as the motive force and cleaning agent, a considerable amount of fluid remains in bore 35 of the cylinder. This fluid, such as oil, is for all practical purposes, lost, as it is discharged through the discharge line 88 into a sewer where it may cause excessive pollution or into a tank where some of it may be reclaimed. This action taking place each time the machine is being used to clean another tube, and with hundreds of tubes to be cleaned, this loss of cleaning fluid is expensive.

The loss of cleaning fluid could be partly or wholly eliminated by utilizing compressed air as the motive force and cleaning agent, either alone or in combination with a liquid agent. To accomplish the cleaning process of tubes by this method one may use liquid under pressure for the forward stroke of the piston and cleaning rod assembly and compressed air for the return stroke of the same.

Liquid under pressure may be used to complete the forward or tube cleaning stroke of the pistons and cleaning rod assembly as previously described. During this forward stroke, the operator places a removable stop pin 115 in a hole 116 located in the flat circular plate 90. This pin provides an abutment which contacts the side of the control lever 91 when said lever has been rotated one-eighth of a turn or exactly 45.degree. . When the pressure gauge on cylinder 12 indicates that the cleaning rod assembly 34 has reached the end of its forward stroke, the operator immediately moves the control lever to contact the stop pin 115. Pin 115 was previously positioned to stop the lever at the one-eighth turn position as indicated by the letter "B" in FIG. 6, thus closing the four-way valve 41 and preventing it from communicating with all of the pressure and discharge lines. The operator then presses the push button 94, which controls the flow of air through the one-way air valve 92 and holds it down during the entire return stroke of the cleaning rod and piston assembly 34, which is accomplished by the pressure exerted on the front face of the pistons by the compressed air as it flows from its source through the supply hose 67, T-connection 68, flexible hose 93, air valve 92, flexible hose 95, T-44, discharge pipe extension 43', fitting 45, vertical port 46 in the header member 15, counter bore 47, and the bore 35 of cylinder 12 where it exerts the necessary force on the front faces of the pistons to withdraw the cleaning rod and its attached cleaning tool end or bit from the tube just cleaned.

It should therefore be evident from the above description that utilizing a 50--50 combination of pressurized liquid and compressed air as the motive forces for operating the tube cleaning machine of this invention, results in efficient performance and material savings to the users of the machine.

It should be understood that the tube cleaning machine of this invention, could use compressed air entirely as its motive force and cleaning agent, by merely removing the flexible feed hose 87 from its supply source of liquid under pressure and attaching it to a supply source of compressed air. This system utilizes the forces of compressed air coming through the pair of holes 96 at the end of the cleaning rod to blow out particles of scale and other foreign matter from the tube being cleaned.

Although but one embodiment of the invention has been shown and described, it should be evident to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

Claims

What is claimed is:

1. A tube cleaning device comprising:

a cylinder,

a coaxial shaft sealed therein,

a piston slidably supported in said cylinder,

said shaft having an inner end rotatably connected to said piston,

the outer end of said shaft projecting out of said cylinder and provided with a tube cleaning means,

means for rotating said shaft,

means for connecting the ends of said cylinder alternately to a source of fluid under pressure and to the atmosphere to extend and to retract said shaft and said cleaning means,

a plurality of ports spacedly positioned at predetermined positions along the length of said cylinder and adapted to be alternately connected to said pressure fluid source and said atmosphere by the traverse of said piston across said port,

a pressure responsive means selectively connected to communIcate with a predetermined port in said cylinder to indicate a particular extended position of said pisten and said shaft, and

a sliding bearing within said cylinder between said piston and one end of said cylinder and mounted for movement along said shaft during at least a part of the movement of said piston to extend said shaft for controlling whip lash of said shaft,

said bearing being moved by said piston toward one end of said cylinder during movement of said shaft out of said cylinder and by fluid under pressure when said piston moves said shaft back into said cylinder.

2. The tube cleaning device set forth in claim 1 wherein:

said sliding bearing is detachably held at a given point within said cylinder for movement therefrom toward said one end of said cylinder by said piston as it moves through a predetermined portion of said cylinder during a tube cleaning operation.

3. The tube cleaning device set forth in claim 1 wherein:

said shaft and piston are provided with a passageway therethrough connected with at least one fluid discharge port in said tube cleaning means, and

said fluid under pressure when actuating said piston to extend said shaft forcing fluid through said passageway out of said port in said tube cleaning means to aid in cleaning said tube.

4. The tube cleaning device set forth in claim 3 wherein:

said piston when retracting said shaft forcing at least a part of the fluid in said cylinder in front of said piston formerly used for extending said shaft through said piston and said shaft and out of said port in said tube cleaning means to flush out the tube as said shaft and tube cleaning means are withdrawn therefrom.

5. The tube cleaning device set forth in claim 3 wherein:

said fluid under pressure is a liquid solvent.

6. The tube cleaning device set forth in claim 1 wherein:

said means for connecting the ends of said cylinder alternately to a source of fluid under pressure comprises a valve for connecting one end of said cylinder to a liquid solvent under pressure for extending said shaft and for connecting the other end of said cylinder to air under pressure for retracting said shaft.

7. The tube cleaning device set forth in claim 6 in further combination with:

means in said cylinder for restraining said sliding bearing in substantially the center of said cylinder during a retracting stroke of said shaft and for releasing said sliding bearing for moving toward one end of said cylinder by engagement with said piston when said shaft is moved to its extended position.

8. The tube cleaning device set forth in claim 7 wherein:

said sliding bearing is provided with apertures therethrough for conducting fluid under pressure past said bearing and to said piston for causing said piston to retract said shaft.

9. A tube cleaning device comprising:

a cylinder,

a coaxial shaft sealed therein,

a piston slidably supported in said cylinder,

said shaft having an inner end rotatably connected to said piston,

the outer end of said shaft projecting out of said cylinder and provided with a tube cleaning means,

means for rotating said shaft,

means for connecting the ends of said cylinder alternately to a source of fluid under pressure and to the atmosphere to extend and to retract said shaft and said cleaning means,

a plurality of ports spacedly positioned at predetermined positions along the length of said cylinder and adapted to be alternately connected to said pressure fluid source and said atmosphere by the traverse of said piston across said port, and

a pressure responsive means selectively connected to communicate with a predetermined port in said cylinder to indicate a particular extended position of said piston and said shaft.