US1842563A - Slug for condenser tubes - Google Patents

Description

Jan. 26, 1932.

w. F. OBERHUBER' 1,842,563

SLUG FOR CONDENSER TUBES Filed Jan. 4, 1927 2 Sheets-Sheet l l 1/ I l Jan. 26, 1932. w. F. OBERHUBER 1,842,563 v SLUG FOR CONDENSER TUBES Filed Jan.'4. 1927 2 Sheets-Sheet 2 Patented Jan. 25, 1932 PATENT OFF? "WILLIAM F. OBERHUBER, OF LANSDOWNE, PENNSYLVANIA, ASS IG-NOR T FRANKLIN DEVELOPHEELNT COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA Application filed January 4, 1927.

invention relates to longitudinally perfora l slugs for cleaning condenser tubes and the like, and that operate by being driven wugh the dirty tubes by the pressure of l ich a fluid as air, steam or water.

it purpose of my invention is to simultaneously rotate and fmwvardly progress a rubber plug or slug through a condenser tube in; means of the drii'in fluid, using the fluid pressure back of the i to drive it forward and the i'iuid passing through the slug to 1'0- te lo the sing as well as to Wash away loosened dirt from ahead of the slug.

it further purpo:-:e is to enlarge the rear end of a rubber slug and provide a flared opening therein to cooperate with longitudinally extending external guides which maintain the slug in alignment and form clearance spaces between them to receive dislodged dirt.

further purpose is to removably mount 'ing at the rear of a slug, anchoring the spring! to the forward end of the slug, using 'priug or not according to the condition e corulenser tube to be cleaned. it A further purpose is to guide the driving fluid to the surface of a slug at the front oi the slug by means of circumferentially extending interior grooves which flare to or nearly to the full diameter of the slug.

L ier purpose to use a hollow rubber slug a scraper spring behind it and to determine the tightness of the spring against the bore of the tube by the force re- "u to pull the spring.

5 is fi'uther purpose .is to use spirally eX- tending interior fluid passages in the slug, both for the purpose of guiding a discharge against the tube in ad nurse of the slugs and to pass anchors for a trailing scraper carried by the slug.

further purpose is to trz'insform longitudinally extending guide ribs upon a slug eX- terior into ircuuiferoutially moving scrapiuosu r to b v the reaction of operating fluid pa nun through the slug along spiral paths.

have preferred to illustrate a few slightly different slugs only, all of one general form, aiming the many in which my invention may appear. selecting slugs which are practical, efficient, reliable and inexpensive and which SLUG FOR CONDENSER TUBES Serial No. 158,879.

at the same time Well illustrate the principles of my invention.

Figure 1 is a side elevation of one of the slugs, corresponding to the view from the position of line 11 in Figure 2.

Figure 2 is a rear end elevation of the structure seen in Figure 1.

Figure 3 is a front end elevation of the structure seen in Figure 1 corresponding to the View from line 3-3 of that figure.

Figure i is a section taken upon the line 4il of Figure 5.

Figure eta is a section slightly modified from Figure Figure I is a section corresponding to line 55 of l igure 4.

Figure 6 is a fragmentary longitudinal view of a tube section and of one of my slugs in place to which I have added a spring scraper, the view corresponding to line 66 of Figure '2' but being slightly modified therefrom.

Figure 7 is a section upon line 7--7 of Figure 6.

Figure 8 is a side elevation of a second slug facing in the opposite direction from Figure 1.

Figure 9 is a front elevation of the structure seen in Figure 8.

Figure 10 is a section of Figure 9 taken upon line 10-10.

Figure 11 is a rear elevation of the structure seen in Figure 8.

Figures 12 and 14- are front and rear elevations respectively of a slightly changed slug.

Figure 13 is a section of Figure 12 upon line 1313.

Figure 15 is a longitudinal section of a structure corresponding to Figure 10 but with a scraper in position.

Figure 16 is a rear end elevation of the structure seen in Figure 15.

In the drawings similar numerals indicate like parts.

This invention is in part a development of the subject matter of my application, Ser. No. 85,533, filed February 2, 1926.

In the above application I disclosed and claimed an internally rifled slug in order to make it rot-ate during its passage through a condenser tube by the reaction of the driving fluid. I did not at the time of the prior invention appreciate the advantage of rifling or internally spiralling throughout the full length of the slug and particularly throughout the discharge end of the perforation. I also did not appreciate the advantage of providing simultaneous clearance and guiding surface in front of the Wiping portion of the slug.

Describing this form shown in Figures 1-5:

The slug is made of rubber and comprises externally a forwardly extending ribbed guiding portion having ribs 20 and intervening grooves 21 with a cylindrical enlarged sealing flange 22.

The slug is hollow and is grooved so as to provide spiral passages 23 which are farther apart at the front and at the rear than at the middle. The enlarged opening provided by the enlargement of these passages at the rear at 24 facilitates nearly radial compression of this rear flange 22 so that the slug may pass through a tube 25 (Figure 6) somewhat smaller than the diameter of the flange 22. At the same time this inwardly compressible flange becomes radially expansible by the pressure of the driving fluid so that the fit of the flange against the tube is a function both of the expansive power of the rubber and of the pressure and character of fluid by which the slug is being driven.

The spiral passages are not only further from the center at the front and rear than at the middle, but are larger in cross-section, considered merely as passages, also at these two ends providing a convergence and with a compressible fluid a compression of fluid from the rear to the middle with a corresponding divergence and expansion (with an expansible fluid) of the fluid streams beyond the middle to their point of discharge near the circumference. The discharging streams leave the slug near the circumference with a. direction which is spiral and which is also divergent from the axis, with the result that they strike the interior of any tube 25 in a direction which is diagonal and a composite of these two slopes and which is highly desirable for the purpose of cutting the dirt ahead of the advancing slug.

Ordinarily these slugs are driven by water, steam or air. Where water is used there is no bodily compression nor expansion of the stream, but with steam and air there will be compression from the rear to a predetermined point shown near the middle and expansion beyond this point. with either water or steam the fluid will have the effect of wetting the layer of dirt within the tube and thus facilitating its removal.

The construction and location of the spiral passages provides an open interior within the grooves to passages at the front and a plug tended to tbe shown in Figure 4. In it the forward flares of the passages in their entireties as well as of the sections of each indiif idual passage extend clear to the front surace.

The expansion of the individual passages toward the forward end may desirably be omitted where the guiding. fluid is a liquid. Vfhere the tube is used sometimes with air or steam and sometimes with water I prefer to have the forward end of the passages through the slug expand.

In the form shown in Figures 6 and 7 the slug is desirably the same as in Figures 1 to 5.

When a condenser tube is very dirty, particularly when hard scale is deposited upon the inside of the tube, the rubber material of the slug is inadequate to remove the scale. I then fasten a spiral spring 27 to the slug. The forward spiral of the spring slug is of reduced size and surrounds the head of a fastening member 28 which extends through the slug and is anchored at the forward end thereof. Preferably the fastening member is provided with a head 29 and two stems 30 which pass through two of the slug passages and registering passages 31 of a washer 32. They are then bent over the washer at 32, thus securing and anchoring the spring.

lVhen the slug is driven through a tube and the spring is in place the slug pulls the spring along and the pull is carried upon the washer through the divided stem of the fastening member. The spring tends to unwind with the strain upon it, reducing its diameter in proportion to the resistance met, i. e., according to the volume and hardness of the scale.

The spring and washer are very readily removable by turning up the ends of the stem members. However, ordinarily, a small number of slugs with springs will be kept for this service. Unless the tube to be cleaned is in bad condition the spring will usually not be needed. 7 When driving the slug through a condenser tube without its auxiliary spring, I prefer to use air or steam as a driving medium but find it preferable to use water when the spring is used.

In operation the space 21 between the external guiding ribs 20 provides a region for receiving dirt wiped from the inside of the tubes. The blast of driving fluid is discharged forwardly and circumferentially near the forward edge of the slug and drives much of the dirt ahead and out of the way. Usually a slug will be sent through a number of times before a tube is cleaned. If the tube be very dirty initially the spring member shown in Figures 6 and T will preferably be used at first to take out the rough heavy scale. Subscquently the slug may be sent through a n umber of times without the spring for final cleaning and polishing.

It find that T can clear the dirt in large measure from the grooves 21 by either of two methods through the use of openings from these channels into the adjacent passages 23. i prefer to use these openings for suction of the dirt and scale through them into the nozzle channels referred to as passages 23 and when so used place the openings near or beyond the middle of the length of the grooves, preferably at the points of greatest restriction of the passages where the velocity of the luiiii is accordingly greatest. The openings are so shown in Figure l and are there rai'lially. lowever they can be sloped laterally or in planes through the axis or as a combination of these.

The holes 3-1- are shown in Figures 1, 1 and in only and no holes are shown in Fig are (3. it will be obvious that they could be used in any of the structures shown. They n enter the channels 23 at any point Where re will be an injector effect and their ternnnation at the points of greatest passage ronz-iitriction has been determined upon for the purpose of getting the highest fluid velocity for suction and for this purpose only.

I find that sucking of the dirt into the dream of driving fluid or gas through the openings 34 has an advantage additional to the clearing of the paces or grooves 21 in that the dirt thus fed into the driving stream contains some scale and when driven by the stream has a sand blast effect upon the scale and dirt engaged by the stream in advance of the plug.

The other means of using these openings is by outward blast into the grooves as distinguished from the suction means. I have shown it in connection with Figures 8, 10 and ii. but not in 15. In Figures 8, 10 and 11 the openings 36 connect with the interior toward the rear of the sing and open into the 'ear parts of the grooves 21 so that there is a blast of air through these rear openings and out through the grooves, as distinguished from the suction present in the other form. lilvidently these blast openings shown in Figures a, 10 and 11 can be applied in any of the figures.

lt is, of course, evident that the two means of clearing the grooves of dirt and scale are capable of use together so that fluid pressure entering the grooves at the rear from opening; such as 36 will supply fluid pressure in the grooves to assist in the inward flow of fluid, dirt and scale due to suction through the openings 34. As seen in the section 4a these two sets of openings may be mechanically assisted by forming a slight pocket 37 extending transversely of each groove 21 so that dirt and scale crowding in toward the front by reason of the forward movement of the slug will be trapped at this point and will more conveniently and effectively be sucked down by the suction of the inducing fluid and forced down into the inducing fluid by the pressure of fluid passing through openings 86.

l: have omitted the openings 34 and 36 from some of the slugs, have shown one set 3% or one set 30 only in others and both SQLS of openings in Figure do for the purpose of indicating that these parts of my invention may be used or not as preferred and where used, the suction alone may be applied or the pressure alone, or both suction and pressure as preferred.

In Figures 8 to 16 the slug is solid except for separate openings 23 and, where a spril'lg is to be used, a central hole 88 shown in Figures 15 and 16. Four openings 23 are shown in each of Figures 811 and 15 and 16 whereas asingle opening 23 only is shown in Figures 12--1il. Each of the openings 23 is spiraled and is flared from back to front. They do not diverge radially.

Though the split pin form of fastening the spring shown in Figures 6 and 7 is preferred and could be used I have shown a bolt 39 fitting into a front washer l0 used as a nut,

just to indicate that other fastenings may beused. It may be burr-ed to lock the bolt from withdrawal.

It will be evident that air or steam may be expanded, diverged from the axis and given a circumferential whirl at the same time by the shape and location of the fluid passages, or that any one or two of these features may be used together where the entire combination is not desired.

The reaction of the fluid against the walls of the passage and of the ejected fluid against the air and against the interior walls of the tube result in turning the slug while it is passing through the tube. At their forward ends the ribs are expanded against the tube interior by the pressure of the fluid against the outer walls of the passages. lit will be noted that the passages preferably agree in number with the number of ribs and terminate directly beneath them.

The rotation of the slug causes the longitudinal edges of the guiding ribs to assist in cleansing the interiors of the tubes, the dirt scraped and rubbed off accumulating in the grooves between these guiding ribs.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain part or all of the benefits of my invention without copying the structure shown, and I, therefore, claim all such in so far as they fall within the reasonable spirit and scope of my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. A slug for cleaning condenser tubes, comprising a hollow rubber body, a rear sealing flange and external forward guiding ribs, the body having an interior spiralled groove reduced in cross-section from the rear to approximately the middle and enlarged forwardly thereof.

2. A slug for cleaning condenser tubes comprising a hollow rubber body having a plurality of interior fluid passages converging toward one another and reducing in distance from the axis from the rear to an intermediate point and diverging from one another and increasing in distance from the axis from that point to the front of the slug.

3. A slug for cleaning condenser tub-es, comprising a hollow rubber body having a plurality of interior fluid passages converging toward one another and reducing in distance from the axis from the rear to an intermediate point and diverging from one another and increasing in distance from the axis from that point to the front of the slug, and having a solid portion at the front between the fluid passages.

4. A slug having a rubber body, said body having spiralled passages from rear to front diverging from the middle portion of the length of the slug.

5. "x slug having a rubber body, said body having spiralled passages from rear to front converging from the rear for a portion of the length of the slug and then diverging to the front of'the slug.

6. A slug having a rubber body, said body having a centrally open hollow forwardly from the rearward end for a portion of the length of the slug and including a plurality of grooves about the open central portion of the hollow and having passages spiralling and diverging forwardly from the hollow to the front of the slug.

7. A slug having a rubber body, said body having a hollow forwardly from the rear ward end for a portion of the length of the slug and a plurality of grooves about the hollow communicating therewith and passages spiralling, flaring and diverging from the forward end of the hollow to the front of the slug.

8. A rubber slug hollow forwardly for a portion of its length from its rearward end, having forwardly converging spiralled grooves extending forwardly from the rearward end of the hollow and connecting with spiralled passages from the hollow to the front of the slug and disposed about the center line of the slug, the grooves and passages being larger in cross-section at the rear and front of the slug respectively than at intermediate points of the slug.

9. A. rubber slug hollow for a portion of its length from its rearward end, having forwardly spiralled grooves about the hollow and passages connected therewith spiralling to the front of the slug and disposed about the center line thereof at the front, the grooves and passages being larger in crosssection at the rear and front respectively than at intermediate points of the slug, respectively forwardly converging toward the axis and diverging from the axis.

10. In a slug for cleaning condenser tubes, a rubber body, guiding ribs exteriorly of the body extending longitudinally over the middle of the length and to the front portion of the body, and a rear flange larger than the ribs and adapted to be swelled by the driving fluid, the rear end of the body being hollow within the flange.

11. A slug of rubber having a plurality of external longitudinally extending guiding ribs and corresponding passages through the body terminating beneath the ribs.

12. A slug of rubber having its front end formed with alternating ribs and grooves and having forwardly flaring passages through the slug terminating respectively beneath the ribs. I

13. In a slug for cleaning condenser tubes, a rubber body, a scraper adapted to be dragged by the body, a pressure-distributing plate across the front of the slug, and a fastener for the scraper passing through the body and anchored in the plate.

M. In a slug for cleaning condenser tubes, a rubber body having passages through it diverging from the axis toward the forward end and external longitudinal ribs on the forward part of the body forming grooves between them, there being openings from the grooves to the passages providing suction from the grooves into the passages by ejector effect.

15. In a slug for cleaning condenser tubes, a hollow rubber body, longitudinally extending ribs on the forward part of the body forming grooves between them, and blast openings from the rear part of the hollow body into the grooves.

16. In a slug for cleaning condenser tubes, a hollow rubber body, a rear flange: on the body and longitudinally extending ribs on the body forming grooves between, there being blast openings toward the rear into the grooves and suction openings ahead of the blast openings, extending from the grooves to the hollow of the body.

WILLIAM F. OBERHUBER.

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