US3250320A - Heat exchanger bundle - Google Patents

Description

May 10, 1966 c. v. BELANGER HEAT EXGHANGER BUNDLE Filed Nov. 9, 1961` 1NVENTOR.

United States Patent O 3,250,320 HEAT EXCHAN GER BUNDLE Celestin Victor Belanger, Beaumont, Tex., assigner to Henry W. Allen, trustee, Beaumont, Tex. Filed Nov. 9, 1961, Ser. No. 151,403 7 Claims. (Cl. 165-94) My invention relates in particular to a tubular type heat exchanger of the classes yusually referred to as floating head, hairpin, fixed tu-be sheet, etc., which are used in refining and chemical industries and steam generating plants.

The ever increasing and perplexing problem of fouling on the heat transfer surfaces, especially the external surfaces of the tubes, has been a plague to the industries for years, and the tube bundle combination in this art is s-uch that the tube bundles cannot be adequately cleaned once they become fouled. This fouling occurs in a few months .in many proces-ses, and the bundles currently used require costly and tedious time consuming efforts for removal and cleaning as well as decreasing efficiency as the cumulative fouling progresses. In many instances costly spare alternates are necessary because the time for cleaning and reinstalling cannot be tolerated process wise. In all instances the fouling materials cannot be completely removed from the external surfaces of the tubes, yand in many instances this fouling is cumulative to the extent that complete replacement of the tube bundle is necessary. Furthermore, the undesirable characteristic of distorted tubes and tube sheets is unavoidable and uncorrectable because of current handling and cleaning methods. Distorted tubes reduce the efficiency of exchangers because they disrupt the liow pattern of the heat exchange streams, and distorted tube sheets make it impossi-ble to properly fi-t the bundles in the shells.

The modern art of tube bundle assemblies has remained essentially the same `for many years and no attempts have been made as an objective to provide an exchanger assembly with the structural characteristics tha-t provide means for preventing cumulative fouling on ythe external sur-faces of the tubes While the exchanger is in operation.

The principal portions of the exchangers used in refining and chemical industries where fouling occurs are the fioating head and hairpin types with the bundle portion constructed as an integral unit which is removable from the exchanger shell for cleaning or retub-ing. The solution yto the fouling problem is and has been beyond the realm of mechanical skill because the present and past art of heat exchanger assemblies has never been and is not at the present suitable -to cope with this plague.

The primary object of my invention is to provide a heat exchanger with novel and improved means for scraping the fouling materials from the external surfaces of Ithe tubes while the bundle is in operation in order to maintain maximum heat transfer at all times. This will eliminate costly process losses from shutdowns, maintenance costs of removing and cleaning bundles and providing costly spare bundles which are necessary because downtime for bundle cleaning, in many instances, cannot be ltolerated process wise.

VOther objects and features of novelty will be apparent from the following specification when read in connection with the accompany-ing drawings in which certain embodiments of the invention are illustrated by Way of example.

In the drawings:

FIGURE 1 is a vertical sectional View through a somewhat d-iagr-ammatically disclosed exchanger and illustrating one embodiment of the invention;

FIGURE 2 is a fragmentary sectional view showing a modified form of tube scraper elements; and

3,250,320 Patented May 10, 1966 'FIGURE 3 is a similar view showing a still further adaptation of thel type of scraper shown in FIGURE 1.

The exchanger shell is indicated at 1 in FIGURE 1 of the drawings and a stationary tube sheet at 2. A oating head A'tube sheet is indicated by the reference numeral 3. The tubes themselves are indicated at 8 and are surrounded by the spiral tube scraper elements 13 which are disposed for freer rotative movement around the tubes lto which they are applied.

For the purpose of rotating these spiral Scrapers there is provided the drive gear shaft upon which a drive gear -19 is keyed as at 23. The shaft is mounted in bearings 22 appropriately secured within the housing 21 which housing may be fixed in sealed relationship to the shell 1 as by means of the bolts 24.

The drive gear 19 enters the shell 1 through an opening therein and meshes with a gear 18 rotatably mounted upon one of the tubes 8 and having the spiral cleaners or Scrapers fixed thereto so as to rotate therewith. Each of the tubes 8 is provided with a similar gear 18 meshing with the gears 1S of adjacent tubes, and each of the gears 18 on its respective tube carries the scraper or cleaner elements '13.

Thus, the rotation of the drive gear 19 causes the Scrapers 13 to rotate around the tubes t-o shear and scrape any deposited accretion of fouling material from the external surfaces of the tubes.

If desired, friction drive wheels and driven wheels may be used instead of the cog-Wheels or gears 18 and 19.

In FIGURE 2 of the drawings the scraping elements comprise the Washers 17 which are preferably spaced apart equally and sleeved over the `tubes 8. These washers are attached to one another and to the hub or end of the cog or gear 18 by means of the longitudinally extend- -ing rods 16. Thus, these washers are caused to rotate around the tube and to break up any incrustation of fouling material which may have been deposited thereon.

Of course, ythe main drive shaft 20 may be driven by any suitable source of power and the frequency and technique of operation of the tube cleaners are dependent upon the rate of deposition of the fouling material and this must lbe determined for each individual installation.

-In FIGURE 3 of Ithe drawings there is shown a modification of the spiral cleaner arrangement described in connection with FIGURE l. In this modification the spiral tube Scrapers -13 are wound about'the tubes in opposite lays and when the scrapers are sleeved over the tubes they overlap one another at intervals along adjacent tubes 8. In this manner rotating motion is imparted to all the tube Scrapers 13 from the initial scraper 13 which is the only one to have the gear or cog 1S secured `thereto. Thus, in effect, the Scrapers on all o-f the tubes except the initial one'are geared to adjacent Scrapers and act themselves as transmission gears, the initial drive of course having been applied to the drive shaft 20 and acting through the drive gear 19 upon the gear 1S carried by the Iini-tial tube.

It is obvious that minor changes in details of construction can be made without departing from the spirit of my invention.

Having fully described the parts of my invention and its mode of opera-tion, I claim:

1. In combination with ya heat exchanger having a shell, a pair of spaced tube sheets, and a plurality of tubes having ends disposed in apertures i-n said tube sheets, a tube scraper installation which comprises a plurality of scraper devices, each .mounted for free rotation on one of the tubes to remove accretions therefrom, a drive shaft, a rotatable driving member rigidly carried by said shaft and disposed in driving relationship with at least one Of said scraper devices to rotate the latter, a-nd the scraper devices of adjacent tubes being in driving contact with each other, whereby rotation of said drive shaft causes all of the scraper members to rotate on their respective tubes.

2. The combination as set forth in claim 1 in which said scraper devices each include a spiral coal scraper element, and in which adjacent scraper elements are coiled in opposite directions whereby the coils intermes-h in driving relationship.

3. In combination with a heat exchanger having a shell, a pair of spaced tube sheets, and a plurality of tubes 'having ends disposed -in apertures in said tube sheets, av

tube .scraper installation which comprises a plurality of driven sleeve elements, each mounted for -free rotation on one of the tubes, a scraper member sleeved on each of said tubes for rota-tion therearound to remoive accre? tions therefrom, means rigidly securing each of said scraper members to the sleeve element carried by the same tube, a drive shaf-t, a ro-tatable driving member rigidly carried by said shaft and disposed in driving relationship with at least one of said sleeves to rotate the latter,

and the sleeves of adjacent tubes being in driving Contact 4 toothed gear in mesh with at least one of said smaller gears.

5. The combination as set forth in claim 4 in which `the scraper members secured to the small toothed gears Icomprise spiral elements surrounding the respective tubes.

6. T'he combination as set forth in claim 4 in which the scraper members comprise annular washers surrounding the respective tubes and a series of longitudinal rods eonnecting said Washers with each other and With their respective toothed gears;

7. The combination as set forth in claim 3 in which an auxiliary casing is provided secured in common sealed relationship With the interi-or of said shell, and in which said driving member and at least a portion of-said drive shaft is housed Within said casing, and an opening provided through which said driving member may extend [from saidoasing into said shell to meshv with the tubecarried gears.

References Cited by the Examiner UNITED STATES PATENTS 10,964 5/1854 McMullen 122-379 392,548 11/ 1888 'Pickett 122--379 ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, PERCY L. PATRICK,

` Examiners.

Claims (1)

1. IN COMBINATION WITH A HEAT EXCHANGER HAVING A SHELL, A PAIR OF SPACED TUBE SHEETS, AND A PLURALITY OF TUBES HAVING ENDS DISPOSED IN APERTURES IN SAID TUBES SHEETS, A TUBE SCRAPER INSTALLATION WHICH COMPRISES A PLURALITY OF SCRAPER DEVICES, EACH MOUNTED FOR FREE ROTATION ON ONE OF THE TUBES TO REMOVE ACCRETIONS THEREFROM, A DRIVE SHAFT, A ROTATABLE DRIVING MEMBER RIGIDLY CARRIED BY SAID SHAFT AND DISPOSED IN DRIVING RELATIONSHIP WITH AT LEAST ONE OF SAID SCRAPER DEVICES TO ROTATE THE LATTER, AND THE SCRAPER DEVICES OF ADJACENT TUBES BEING IN DRIVING CONTACT WITH EACH OTHER, WHEREBY ROTATION OF SAID DRIVE SHAFT CAUSES ALL OF THE SCRAPER MEMBERS TO ROTATE ON THEIR RESPECTIVE TUBES.

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