AU692203B2 - Cleaning system for cleaning the inside of fluid conducting tubing and associated apparatus - Google Patents

Description

ly~ OPI DATE 06/06/95 AOJP DATE 27/07/95 IN APPLN. ID 11847/95 |||fliii iIIIIU(| PCT NUMBER PCT/US94/13469 I II1 lIIII III IIIfl 1111111111 1 lll AU9511847 (51) International Patent Classification 6 F28G 1/12 (11) International Publication Number: Al (43) International Publication Date: WO 95/14205 26 May 1995 (26.05.95) (21) International Application Number: (22) International Filing Date: 18 N Priority Data: 08/154,062 18 Novemtb 08/258,887 13 June 199 08/258,888 13 June 199 PCT/US9,13469 I ovember 1994 (18.11.94) (81) Designated States: AM, AT, AU, BB, BG, BR, BY, CA, CH, CN, CZ, DE, DK, ES, FI, GB, GE, HU, JP, KE, KG, KP, KR, KZ, LK, LT, LU, LV, MD, MG, MN, MW, NL, NO, NZ, PL, PT, RO, RU, SD, SE, SI, SK, TJ, TT, UA, UZ, VN, European patent (AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OAPI patent (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), ARIPO patent (KE, MW, SD, SZ).

Published With international search report.

er 1993 (18.11.93) 4 (13.06.94) 4 (13.06.94) (71) Applicants: C.Q.M. LTD. [IL/IL]; 9, Shmotkin Street, 2nd floor, Old Industrial Area, 58117 Rishon Lezion (IL).

FRIEDMAN, Mark, M. [US/IL]; 4/9 Yehuda Halevi, 43556 Raanana (IL).

(72) Inventor: PEERY, Moshe; Kibbutz Yotvata (IL).

(74) Common Representative: FRIEDMAN, Mark, do Sheinbein, Robert, 2849 Birchtree Lane, Silver Spring, MD 20906

(US).

92 0 3 (54) Title: CLEANING SYSTEM FOR CLEANING THE INSIDE OF FLUID CONDUCTING TUBING AND ASSOCIATED

APPARATUS

(57) Abstract A cleaning system for cleaning the inside of fluid conduting tubing The cleaning system includes a plurality of balls (26) entrained by a fluid flowing through the system, separation apparatus (28) for separating the balls (26) from the fluid downstream of the tubing accumulator apparatus (60) for accumulating the balls downstream of the separation apparatus storage apparatus (62) for storing a volume of injection fluid and a compressor (64) for selectively providing a supply of compressed air into the storage apparatus (62) such that a portion of the volume of injection fluid passes through the accumulator apparatus (60) for entraining some of the balls (26) therewith for injection upstream of the tubing (14), 91L~ ~BPl~s

~BQIBIPI~BPI~C~~

WO 95/14205 PCT/US94/13469 CLEANING SYSTEM FOR CLEANING THE INSIDE OF FLUID CONDUCTING TUBING AND ASSOCIATED APPARATUS FIELD AND BACKGROUND OF THE INVENTION The present invention relates to systems using balls for cleaning the inside of tubing in condensers and other forms of heat-exchangers in general. The present invention further relates to separation apparatus for separating balls from a flow of liquid entraining the balls incorporated within such systems. The present invention still further relates to apparatus including a compressor for injecting a volume of liquid into a liquid conducting system.

Systems using balls for cleaning the inside of fluid-conducting tubing for preventing the build-up of coatings or any other fouling inside the tubing are known in the art. Such systems generally include separation apparatus and ball recirculation apparatus. Separation apparatus is deployed between the downstream side of the fluid conducting tubing and ball recirculation apparatus and is used for separating the balls from the flow of fluid circulating through the system after each pass of the balls through the tubing for delivery to the ball recirculation apparatus. Ball recirculation apparatus is deployed between the separation apparatus for receiving balls therefrom and the upstream side of the fluid conducting tubing and is used for recirculating the balls through the tubing by injecting them at a positive fluid pressure into the upstream side of tubing.

Conventional cleaning systems are known to suffer from a number of disadvantages. First, it is well known that separation appa.ratus which does not facilitate the delivery of balls to the ball recirculation apparatus detracts from the overall efficiency of a cleaning system. Second, ball recirculation apparatus which uses continuously driven pumps for recirculating the balls, for example US Patents 3,882,931 to Kumagai and 4,234,993 to Kintner, are not only expensive but also suffer from considerable downtime for maintenance and repair purposes. While, ball I .rrPllp~ PP" ~Sr ~e I- r I I I I- WO 95/14205 PCT/US94/13469 2 recirculation apparatus which uses a mechanically actuated ejector for ejecting the balls back into the upstream side of the tubing, for example US Patent 4,865,121 to Ben-Dosa, are highly susceptible to malfunctioning becaase of the tendency of the balls to get wedged between the ejector and a separator screen and therefore also require considerable downtime for maintenance and repair purposes. And third, it is well known that considerable volumes of conducting fluid, typically water, are discharged as waste.

There is thus a widely recognized need for, and it would be highly advantageous to have an inexpensive and efficient cleaning system for cleaning the inside of fluid conducting tubing which overcomes the abovementioned disadvantages.

SUMMARY OF THE INVENTION The main object of the present invention is for a low cost, simple and efficient cleaning system for cleaning the inside of fluid conducting tubing and associated apparatus.

Hence, there is provided according to a first aspect of the present invention, a cleaning system for cleaning the inside of fluid conducting tubing, the cleaning system comprising: a plurality of balls entrained by a fluid flowing through the system; separation apparatus for separating the balls from the fluid downstream of the tubing; accumulator apparatus for accumulating the balls downstream of the separation apparatus; storage apparatus for storing a volume of injection fluid, the storage apparatus being in communication with the accumulator apparatus, the storage apparatus being in communication with a point upstream of the tubing; and a compressor for selectively providing a supply of compressed air into the storage apparatus for injecting a portion of the volume of injection fluid from the storage apparatus to the point upstream of the tubing, a fraction of the volume of injection fluid passing through

~M

PI~I$ILI~L~L~BI~-

WO 95/14205 PCT/US94/13469 3 the accumulator apparatus for entraining some of the balls therewith for injection upstream of the tubing.

According to a further n"ature of the present invention, the accumulator apparatus and the storage apparatus are combined in a single housing.

According to a still further feature of the present invention, the housing includes a sieve and a funnel with a downward depending tube.

According to a yet still further feature of the present invention, the accumulator apparatus and the storage apparatus are configured as two separate airtight housings.

According to a yet still further feature of the present invention, the storage apparatus is at least partly filled by fluid run-off from the accumulator apparatus.

According to a yet still further feature of the present invention, the system further comprising a. pressure decreasing device for decreasing the pressure in the storage apparatus.

According to a yet still further feature of the present invention, the pressure decreasing device is a release valve.

According to a yet still further feature of the present invention, the pressure decreasing device is a pump.

According to a yet still further feature of the present invention, the system further comprising sensing means for sensing the level of the volume of fluid in the storage apparatus.

According to a yet still further feature of the present invention, the system further comprising a timer for operating the system.

There is also provided according to a second aspect of the present invention, separation apparatus for separating a plurality ofballs circulating through fluid conducting tubing having an upstream side and a downstream side, the separation occurring at the downstream side of the tubing, the separation apparatus comprising: a conduit having an inlet in flow I IbBBB I~IP~PLIIII~~II~L~ B~B~illdPI~ 1PI~ WO 95/14205 PCT/US94/13469 4 communication with the downstream side of the tubing, a ball outlet connected to a ball recirculation apparatus for recirculating the plurality of balls to the upstream side of the tubing and a fluid outlet connected to the upstream side of the tubing; and a generally cylindrical sieve substantially extending lengthwise between the inlet and the ball outlet in the conduit for trapping the plurality of balls therein as fluid continually flows from the inlet to the fluid outlet.

According to a further feature of the present invention, the crosssectional area of the inlet is substantially equal to the cross-sectional area of an outlet header neck of the tubing.

According to a still further feature of the present invention, the cross-sectional area of the sieve is substantially equal to the cross-sectional area of an outlet header neck of the tubing.

According to a yet still further feature of the present invention, the total open area of the sieve is at least approximately five times its crosssectional area.

According to a yet still further feature of the present invention, the total open area of the sieve is at least approximately five times the crosssectional area of an outlet header neck of the tubing.

According to a yet still further feature of the present invention, the ball outlet is located substantially center to the sieve.

According to a yet still further feature of the present invention, the apparatus comprising means for reducing turbulence in the flow of fluid within the vicinity of the fluid outlet.

According to a yet still further feature of the present invention, the apparatus further comprising means for reducing turbulence in the flow of fluid within the vicinity of the ball outlet.

According to a yet still further feature of the present invention, the apparatus further comprising means for urging the plurality of balls toward the ball outlet.

a IPrl~ll~qC~ ~Pkq% ~'1 YPI ~aar WO 95114205 PCT/US94/13469 According to a yet still further feature of the present invention, the apparatus further comprising means for compacting the motion of the plurality of balls such that the excursion of the plurality of balls from the axis of the ball outlet is decreased.

According to a yet still further feature of the present invention, the apparatus wherein the sieve includes a non-perforated portion.

According to a yet still further feature of the present invention, the apparatus wherein the sieve converges from the inlet towards the ball outlet.

According to a yet still further feature of the present invention, the apparatus wherein the sieve includes a constricted waist portion.

According to a yet still further feature of the present invention, the apparatus further comprising an insert extending from the ball outlet toward the inlet.

According to a yet still further feature of the present invention, the apparatus further comprising a second separation apparatus in parallel with the first separation apparatus, the second separation apparatus including a conduit having an inlet in flow communication with the downstream side of the tubing, a ball outlet connected to the inlet of the ball recirculatikn apparatus and a fluid outlet connected to an outlet fluid line, and a generally cylindrical sieve substantially extending between the inlet and the ball outlet.

According to a yet still further feature of the present inv,.ntion, the apparatus wherein the inlet of the second separation apparatus is substantially opposite the inlet of the first separation apparatus.

According to a yet still further feature of the pres'. ;nvention, the apparatus further comprising first and second valves deployed on the first and second fluid outlets, respectively.

There is also provided according to a third aspect of the present invention, a cleaning system for cleaning the inside of fluid conducting I ~a ~C II WO 95/14205 PCT/US94/13469 6 tubing, the system comprising: a plurality of balls entrained by a liquid flowing through the system; separation apparatus for separating some of the balls from the liquid downstream of the tubing; accumulator apparatus for accumulating some of the balls downstream of the separation apparatus; venturi apparatus upstream of the tubing and in communication with the accumulator apparatus for drawing the balls upstream of the tubing; and valve apparatus for selectively diverting substantially all of the liquid to flow through the venturi apparatus.

According to a further feature of the present invention, the accumulator apparatus has a rotatable sieve for assuming a first operative position for catching and accumulating balls and a second operative position for releasing balls when valve apparatus diverts liquid through the venturi apparatus.

There is also provided according to a fourth aspect of the present invention, a cleaning system for cleaning the inside of fluid conducting tubing, comprising: a plurality of balls entrained by a liquid flowing through the system; separation apparatus for separating the balls from the liquid downstream of the tubing; accumulator apparatus for accumulating the balls downstream of the separation apparatus; pump apparatus upstream of the tubing and in communication with the accumulator apparatus for drawing the balls upstream of the pump; and (e) valve apparatus for selectively communicating between the pump apparatus and the accumulator apparatus.

According to a further feature of the present invention, the accumulator apparatus has a rotatable sieve for assuming a first operative position for catching and accumulating balls and a second operative position for releasing balls when valve apparatus diverts liquid through the venturi apparatus.

There is also provided according to a fifth aspect of the present invention, apparatus for injecting a volume of liquid received from a source I ~~ra -a '191 WO 95/14205 PCT/US94/13469 7 of liquid into a liquid conducting system, the apparatus comprising: a compressor for selectively providing a supply of compressed gas; and (b) a tank including: a liquid inlet port selectively in flow communication with the source of the liquid for receiving a volume of liquid, (ii) a liquid outlet port selectively in flow communication with the liquid conducting system for delivering some of the volume of liquid, (iii) an air inlet port selectively in flow communication with the compressor for increasing the prevailing pressure in the tank so as to discharge some of the volume of liquid, and (iv) a pressure release valve for selectively decreasing the prevailing pressure within the tank.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: FIG. I a is a schematic view of a preferred embodiment of a cleaning system for cleaning fluid conducting tubing, constructed and operative according to the present invention, in which the balls of the system are accumulated in ball recirculation apparatus ready for injection upstream of the fluid conducting tubing; FIG. I b is a schematic view of the cleaning system of Figure l a in which the balls are dispersed through the fluid conducting tubing before being trapped in the separation apparatus of the cleaning system; FIG. lc is a schematic view of the cleaning system of Figure I a in which the balls are accumulated in the separation apparatus ready for delivery to the ball recirculation apparatus of the cleaning system; FIG. 2 is a schematic view of the cleaning system of Figure I modified to store all the cooling fluid used to entrain the balls from the separation apparatus to the ball recirculation apparatus; FIGS. 3a-3g are schematic views of the separation apparatus of the cleaning system shown in Figure 1 including improvements and modifications for facilitating the evacuation of balls therefrom; WO 95/14205 PCTUS94/13469 8 FIG. 4 is a schematic view of a novel separation apparatus, constructed and operative according to the teachings of the present invention, including parallel sets of separation apparatus; FIGS. 5a and 5b are schematic views of a second embcd'Aent of a cleaning system for cleaning fluid conducting tubing ai t* i, the teachings of the present invention in which the system is su "fore actuation of its ball recirculation apparatus in FIG. 5a and sometime after actuation of its ball recirculation apparatus in FIG. FIGS. 6a and 6b are schematic views of a third embodiment of a cleaning system for cleaning fluid conducting tubing according to the teachings of the present invention in which the system is shown before actuation of its ball recirculation apparatus in FIG. 6a and sometime after actuation of its ball recirculation apparatus in FIG. 6b; and FIGS. 7a and 7b are schematic views of a preferred embodiment of apparatus for injecting a volume of liquid from a source of liquid to a liquid conducting system before and after injection of a volume of liquid.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is of a cleaning system using balls for cleaning fluid conducting tubing in condensers and other forms of heatexchangers and associated apparatus.

The principles and operation of a cleaning system and the associated apparatus according to the present invention may be better understood with reference to the drawings and the accompanying description.

Referring now to the drawings, Figures la-Ic are schematic views of a cleaning system, generally designated 10, constructed and operative according to the teachings of the present invention, for cleaning a condenser 12 at different stages of operation. Condenser 12 includes fluid conducting tubing 14 through which a cooling liquid, such as water, passes to condense a fluid, such as steam or refrigerant gas, passing through WO 95/14205 PCTIUS94/13469 9 spaces between condenser tubing 14. The cooling fluid is pumped by a pump 20 through a closed circuit including an inlet conduit 22 at the upstream side of condenser 12 connected to the inlet header 16 of condenser 12, condenser tubing 14, and an outlet conduit 24 at the downstream side of condenser 12 connected to the outlet header 18 of condenser 12.

Broadly speaking, cleaning system 10 includes three elements: balls 26 for forced circulation through condenser tubing 14 for cleaning same of bacteria or scale as it forms, separation apparatus, generally designated 28, and ball recirculation apparatus, generally designated 30. Separation apparatus 28 is deployed between the downstream side of condenser 12 and ball recirculation apparatus 30. Separation apparatus 28 is used for separating balls 26 from the flow of fluid circulating through system after each pass of balls 26 through condenser tubing 14. Separation apparatus 28 delivers balls 26 to ball recirculation apparatus 30 via conduit 32. Ball recirculation apparatus 30 is deployed between separation apparatus 28 for receiving balls 26 therefrom and the upstream side of condenser 12. Ball recirculation apparatus 30 is used for injecting balls 26 into the upstream side of condenser 12 via a conduit 34.

Conduits 32 and 34 are provided with one-way normally closed vaives 36 and 38, respectively. One-way valve 36 is opened when balls 26 are being delivered from separation apparatus 28 to ball recirculation apparatus 30 while one-way valve 38 is opened while balls 26 are being injected by ball recirculation apparatus 30 upstream of condenser 12. In addition, conduits 30 and 34 can be provided with normally open valves and 42, respectively, which are periodically closed for maintenance and repair purposes of ball recirculation apparatus Separation apparatus 28 includes a shunt conduit 44 having an inlet 46 connected to the downstream side of condenser 12, a fluid outlet 48 connected to outlet conduit 24 and a ball outlet 50 for delivery of balls 26 WO 95/14205 PCT/US94/13469 via conduit 32 to ball recirculation apparatus 30. Outlet conduit 24 is provided with a valve 52, inlet 46 is provided with a valve 54 and fluid outlet 48 is provided with a valve 56 for controlling the flow of fluid through separation apparatus 28. Typically, valve 52 is closed and valves 54 and 56 are open such that the flow of fluid downstream of condenser 12 is through separation apparatus 28 and not directly along outlet conduit 24. Periodically, valve 52 is opened and valves 54 and 56 are closed for interrupting operation of separator apparatus 28 for cleaning and other maintenance purposes.

Separation apparatus 28 also includes a gernerally cylindrical sieve 58 substantially extending lengthwise within shunt conduit 44 from inlet 46 to ball outlet 50 such that balls 26 are confined within a substantially closed volume therebetween. Within tlh confines of sieve 58, balls 26 perform a generally, slow moving ellipsoid motion denoted A as fluid flows from the downstream side of condenser 12 through shunt conduit 44 to outlet conduit 24.

The design features preferably embodied within separation apparatus 28 to achieve the complete evacuation of balls 26 therefrom during delivery to ball recirculation apparatus 30 are now described. Other improvements in separation apparatus 28 for elicitin, an environment conducive to the complete evacuation of balls 26 from sieve 58 are describe,d hereinbelow with reference to Figures 3a-3g. First, the crosssectional areas of an outlet header neck 18a of condenser tubing 14, inlet 46 and sieve 58 are substantially the same, thereby ensuring a generally smooth, laminar flow of fluid from condenser 12 through separation apparatus 28 to outlet conduit 24. Second, the pressure differential across the wall of sieve 58 is preferably as close to zero as possible, thereby ensuring that balls 26 are not urged against the wall of sieve 58 during their motion within the confines of sieve 58 but rather circulate freely therewithin. This pressure differential is best achieved by providing sieve WO 95/14205 PCT/US94/13469 11 58 with a total open area of at least approximately five times its crosssectional area. However, if the cross-sectional areas of outlet header neck 18a of condenser tubing 14, inlet 46 and sieve 58 are not the same, then the total open area of sieve 58 should be at least approximately five times the cross-sectionai area of the rate determining portion which is typically outer header neck 18a of condenser tubing 14. It should be noted that the total open area of a sieve is defined as the total area of its perforations.

Third, ball outlet 50 is preferably disposed at the center of sieve 58 for best fLilitating the generation of an intense vortex as the prevailing pressure within ball conduit 32 drops below the prevailing pressure within outlet conduit 24, thereby ensuring a complete evacuation of balls 26 from separation apparatus 28.

Broadly speaking, ball recirculation apparatus 30 includes four elements. First, a trap 60 for accumulating balls 26 in readiness for being injected into inlet conduit 22. Therefore, trap 60 is connected to conduit 32 for receiving balls from separation apparatus 28 and conduit 34 for the injection of balls 26 upstream of condenser 12. Trap 60 preferably has sufficient storage capacity to accommodate all balls 26 in circulation.

Second, an air-tight tank 62 for storing a volume of injection fluid which is displaced through trap 60 for entraining balls 26 stored therein to a position upstream of tubing 14. Tank 62 can be filled either by run-off from trap 60 or from a separate source of fluid (not shown) and preferably has sufficient storage capacity for injecting all the balls stored in trap into the mainstream fluid flow. Third, a compressor 64 for providing a supply of compressed air through an air pipe 66 fitted with a valve 68 for increasing the prevailing pressure in tank 62 for causing the displacement of the volume of injection fluid, And fourth, a pressure release device for lowering the pressure in tank 62 for priming cleaning system 10 for a subsequent recirculation of balls 26. Pressure release device 70 can be a valve or a pump. Typically, pressure release valve 70 discharges into a C- WO 95/14205 PCT/US94/13469 12 drain 71. Compressor 64, valve 68 and pressure release valve 70 can be operated by a timer (not shown) according to a pre-determined schedule or manually activated whenever it is desired to clean condenser 12.

In the preferred embodiment of the present invention, trap 60 and tank 62 are preferably combined in a single housing, generally designated 72, having a port 74 through which pass both incoming and outgoing balls 26. Trap 60 includes a sieve 76 for separating balls 26 from the cooling fluid draining through port 74 from conduit 32 and for storing them in readiness for recirculation. Tank 62 is defined by a catch basin 78 for capturing the cooling fluid which runs-off from sieve 76 and a tube downward depending therefrom. Housing 72 can be further provided with a viewing glass 82 for enabling observation of the accumulation and discharge of balls 26 and a drainage valve 84 for cleaning and other maintenance purposes. Alternatively, trap 60 and tank 62 can be provided as discrete units.

With reference now to Figure 2, it is a further feature of the present invention that ball recirculation apparatus 30 can be modified such that most, if not all, of the cooling fluid used for entraining balls 26 thereinto can be recirculated rather a portion thereof being vented as waste to drain 71. In this case, the storage capacity of tank 62 can be increased such that it has sufficient capacity to store all the cooling fluid used for entraining balls 26 into trap 60. Alternatively, depending on the particular installation, a second tank 86 can be provided for receiving the overflow from tank 62 through a connection 88. In this case, compressor 64 pro ides a supply of compressed via an air line 90 fitted with a valve 92 and a pressure release valve 94 connected to tank 86. Ball recirculation apparatus 30 preferably includes sensors 96a and 96b used for determining the maximum and minimum volumes of cooling fluid in ball re;firculation apparatus d r, 11~811111~ ~II W O 95/14205 PCT/US94/13469 13 An operation cycle of cleaning system 10 will now be explained with reference to Figures Ia-lc. As can be clearly seen, Figure la depicts balls 26 accumulated in trap 60 just before their injection upstream of tubing 14, Figure lb depicts balls 26 dispersed through condenser 12 before being separated from the main flow of fluid by separation apparatus 28 and Figure 1 c depicts balls 26 accumulated in separation apparatus 28 before their delivery to ball recirculation apparatus Injection of balls 26 in trap 60 at a positive fluid pressure to a point upstream of condenser 12 is achieved by opening valve 68, closing valve 1 0 70 and activating compressor 64 to provide a supply of compressed air through air supply pipe 66 into tank 62. The prevailing pressure in tank 62 is regulated such that the volume of injection fluid therein is driven through tube 80 and ball trap 60, thereby entraining balls 26 therewith. At the time of discharge of balls 26 from ball recirculation apparatus 30, the prevailing pressure in tank 62 is greater than the downstream pressure of the cooling fluid in condenser 12 causing one way-valve 36 to close and the upstream pressure of the cooling fluid in condenser 12 causing one-way valve 38 to open. Valve 68 is closed and pressure release valve 70 is opened after injection of balls 26, causing a pressure differential to be developed between the cooling fluid flowing through condenser 12 and the prevailing pressure in tank 62 causing one-way valve 38 to close.

Once balls 26 have been injected to a point upstream of condenser 12, they are forcibly circulated through condenser 12 in a generally clockwise direction along with the main flow of cooling fluid through cleaning system 10. Balls 26 pass through condenser tubing 14 and are collected in sieve 58 of separation apparatus 28. Balls 26 perform a generally, slow moving ellipsoid motion denoted A within the confines of sieve 58 as cooling fluid flows from the downstream side of condenser 12 through shunt conduit 44 to outlet conduit 24.

WO 95/14205 PCT/US94/13469 14 After a pre-determined time, typically sufficient to enable most, if not all, of balls 26 to be trapped in sieve 58, ball recirculation apparatus is activated such that the prevailing pressure in tank 62 suddenly drops below the prevailing pressure within outlet conduit 24. The sudden pressure drop causes a relatively abrupt diversion in the flow of cooling fluid through separation apparatus 28 such that most of the cooling fluid is discharged through ball outlet 50 along conduit 32 instead of through fluid outlet 48 along outlet conduit 24. Hence, in sharp contrast to the gentle motion of balls 26 within sieve 58, balls 26 are evacuated therefrom by an intense vortex of cooling fluid entraining balls 26 through ball outlet toward ball recirculation apparatus After evacuation of balls 26 from sieve 58, the pressure in tank 62 is regulated such that the cooling fluid flowing through separation apparatus 28 reverts back to flow through fluid outlet 48 to outlet conduit 24. Balls 26 are accumulated by sieve 76 in trap 60 while the cooling fluid entraining them drains through sieve 76 for storage in tank 62. If necessary, tank 62 is topped up with cooling fluid from a separate source to ensure that a sufficient volume of injection fluid is stored for injecting all the balls stored in trap 60 into inlet conduit 22. The above cycle is performed periodically according to the rate of deposit of coatings and other matters on the inside of condenser tubing 14.

With reference now to Figures 3a-3g, there are illustrated further improvements for implementation in separation apparatus 28 for providing an environment conducive to the complete evacuation of balls 26 from sieve 58. Figures 3a-3c illustrate improvements to separation apparatus 28 in which fluid outlet 48 is disposed toward ball outlet 50 while Figures 3d- 3g illustrate improvements to separation apparatus 28 in which fluid outlet 48 is disposed toward inlet 46. Generally, the arrangement in which fluid outlet 48 is disposed toward ball outlet 50 is preferred because the flow of fluid through fluid outlet 48 tends to urge balls 26 towards ball outlet Ip~i~Y~gar~msranr~uR-prrY-~ WO 95114205 PCT/US94/13469 thereby facilitating their evacuation. However, in certain installations, space requirements do not allow for this arrangement and, therefore, flid outlet 48 is disposed toward inlet 46.

Broadly speaking, the improvements are designed to achieve one or more of the following effects. First, reducing turbulence, particularly within the vicinity of ball outlet 50 as a result of the flow of fluid through fluid outlet 48. Second, urging balls 26 toward ball outlet 50 such that the pull of the vortex generated by the drop in pressure in ball conduit 32 has increased pulling power on balls 26. Third, the pull of the vortex generated by the drop in pressure in ball conduit 32 can be substantially directed toward balls 26 such that the vortex has increased pulling power thereon. And finally, compacting the motion of balls 26 such that the excursion of balls 26 from the axis of ball outlet 50 is decreased, thereby increasing the pulling power of the vortex generated by the drop in pressure in ball conduit 32.

With reference now to Figures 3a-3c, sieve 58 can be adapted to reduce turbulence within the vicinity of ball outlet 50 by providing a nonperforated portion 98 toward the end of sieve 58 disposed toward ball outlet 50. Non-perforated portion 98 can extend from a generally semitrough shape (Figure 3a) to a full cylindrical shape (Figure 3b).

Alternatively, rather than adapting sieve 58, separation apparatus 28 can include a funnel-shaped insert 100 (see Figure 3c) having its narrow aperture toward ball outlet 50 and its wide aperture toward inlet 46. Sieve 58 and insert 100 form a substantially continuous wall to maintain a confined environment for balls 26 between inlet 46 and ball outlet Insert 100 is designed to compact the ellipsoid motion of balls 26 such that the pull of the vortex is accentuated to facilitate evacuation of balls 26 through ball out!'t With reference now to Figures 3d and 3e, sieve 58 can include a non-perforated portion 102 deployed to reduce turbulence within the I WO 95/14205 PCT/US94/13469 16 vicinity of fluid outlet 48, thereby minimizing the disruptive influence on balls 26. Still again, separation apparatus 28 can be equipped with an insert 104 extending from ball outlet 50 toward inlet 46 for directing the pulling power of the vortex generated by the pressure drop in conduit 32 such that balls 26 are more readily evacuated from separation apparatus 28, With reference now to Figures 3f and 3g, modifications to sieve 58 include a converging sieve 106 or a sieve 108 with a constricted waist portion 110. Sieve 106 compacts the excursion of balls 26 toward ball outlet 50 such that the pulling force of the vortex generated by the pressure drop in conduit 32 has an increased pull on balls 26. In contrast, sieve 108 maintains balls 26 in the vicinity of ball outlet 50 once they have passed through constricted waist portion 110, from where the vortex can readily evacuate them from separation apparatus 28.

With reference now to Figure 4, a separation apparatus, generally designated 112, is shown including two sets of separation apparatus 112a and 1 12b. Separation apparatus 112a and 112b have constructions similar to separation apparatus 28 and therefore similar elements are numbered likewise. For reasons to become apparent hereinbelow, inlet 46a is preferably substantially opposite to inlet 46b and separation apparatus 112 further includes valves 114a and 114b deployed on fluid outlets 48a and 48b, respectively.

The operation of separation apparatus 112 is now described. In normal operation, valves 114a and 114b are open such that cooling fluid flowing through condenser tubing 12 flows in substantially equal proportions through separation apparatus 112a and 112b to outlet conduit 24. Hence, balls 26 are drawn in approximately equal quantities into both separation apparatus 112a and 112b after they have passed through condenser tubing 14 following injection by ball recirculation apparatus For the sake of clarity, balls 26 entrapped in separation apparatus 112a are Ai~iWEeAB~aa~slraa~as~arsa~~ WO 95/14205 PCT/US94/13469 17 denoted balls 26a while balls 26 entrapped in separation apparatus 112b are denoted balls 26b.

After entrapment of balls 26, one of valves 114a and 114b is temporarily closed, for example valve 114a, in preparation for the evacuation, in this case, of balls 26a from separation apparatus 112a.

Closing valve 114a causes both the fluid originally flowing through separation apparatus 112a to be diverted such all the fluid flowing through condenser tubing 12 flows through separation apparatus 112b and balls 26a to be substantially stationary within the confines of sieve 58a. The standing of balls 26a facilitates their evacuation by the intense vortex generated when fluid flows through separation apparatus 112a again due to the activation of ball recirculation apparatus 30 to drop the prevailing pressure in ball conduit 32a below the prevailing pressure at inlet 46a.

After evacuation of balls 26a, valve 114a is opened and valve 114b is temporarily closed, thereby enabling the evacuation of balls 26b lmr separation apparatus 112b in the same manner. After balls 26b v, evacuated, valve 114b is reopened such that separation apparatus 112 reverts back to its normal operation.

Figures 5a and 5b illustrates a second embodiment of a cleaning system, generally designated 116, equipped with venturi apparatus, generally designated 118, in communication with trap 60 via conduit 34 for drawing balls 26 into inlet conduit 22 at a point upstream of condenser tubing 14. Venturi apparatus 118 includes a shunt conduit 120 disposed between inlet and outlet pipes 122 and 124, respectively and having a narrow section 126 such that closing of a normally open valve 128 on inlet conduit 22 causes diversion of fluid through shunt conduit 120 such that the high velocity of the fluid through narrow section 126 draws balls 26 from trap 60. It should be noted that even when valve 128 is open, fluid still flows through venturi apparatus 118, however, there is no appreciable drop in pressure at inlet header 16 because o; the relative large diameter I I-C- M ~I~Wre~gar~.~Pprraasrsa~a I--d WO 95/14205 PCTUS94/13469 18 of inlet conduit 22 compared to that of section 126. Trap 60 preferably has a rotatable sieve 130 under the control of an actuator 132 for assuming a first operative position for catching and accumulating balls 26 and a second operative position for releasing balls 26 when valve 128 is closed.

Figures 6a and 6b illustrates a third embodiment of a cleaning system, generally designated 134, where trap 60 is in communication with inlet conduit 22 upstream of pump 20 for drawing balls 26 thereinto when a valve 136 deployed on conduit 34 is opened. Trap 60 preferably has rotatable sieve 130 under the control of an actuator 132 for assuming a first operative position for catching and accumulating balls 26 and a second operative position for releasing balls 26 when valve 136 is opened.

Turning now to Figures 7a and 7b, there is shown a preferred embodiment of a liquid injection apparatus, generally designated 200, constructed and operative according to the teachings of the present invention, for injecting a volume of liquid received from a source of liquid 202 into a liquid conducting system 204. It can be appreciated that liquid injection apparatus 200 is a modified implementation of ball recirculation apparatus 30 and that the liquid received from source of liquid 202 can be either homogenous or heterogenous with the liquid flowing in liquid conducting system 204 depending on the particular implementation of liquid injection apparatus 200.

Apparatus 200 generally includes a tank 206 for storing a volume of liquid received from source 202 and a compressor 208 for injecting some or all of the contents in tank 206 into system 204 as will become apparent below. Tank 206 preferably has an inlet port 210 through which passes incoming liquid along inlet line 212 from source 202 and an outlet port 214 through which es outgoing liquid along outlet line 216 into system 204. Hydraulic one-way valves 218 and 220 are deployed on inlet and outlet lines 212 and 216, respectively, for ensuring the flow of liquid rra~o ~P SI~ I~sgsr~areaasr~ WO 95/14205 PCT/US94/13469 19 from source 202 to system 204. Alternatively, one-way valves 218 and 220 are solenoid operated.

Compressor 208 provides a supply of compressed fluid, typically compressed air, via an air line 222 connected to tank 206 at air inlet 224.

Air line 222 is fitted with a valve 226 and a pressure release valve 228 for controlling the prevailing pressure in tank 206 by enabling a supply of compressed air from compressor 208 and evacuating air from tank 206, respectively. One-way valves 218 and 220, valve 226 and pressure release valve 228 can be operated in a number of modes of operation for the periodic injection of liquid from tank 206 into system 204. Such modes include according to a pre-determined schedule, in response to indications provided by sensors 230a and 230b detecting the level of the volume of liquid in tank 206 or manual activation.

An operation cycle of apparatus 200 is now described with reference to Figures 7a and 7b where Figure 7a shows tank 206 substantially empty while Figure 7b shows tank 206 substantially full of liquid before its injection into system 204. Liquid passes along inlet line 212 through open one-way valve 218 from source 202 and accumulates in tank 206.

Typically, valve 226 is closed and pressure release valve 228 is open such that the prevailing pressure in tank 206 is atmospheric, The volume of liquid in tank 206 increases until the level of the liquid reaches sensor 230a as shown in Figure 7b. On activation, sensor 230a transmits a signal for opening valve 226 and closing pressure release valve 228, thereby establishing flow communication between tank 206 and compressor 208.

Compressor 208 supplies compressed air to tank 206 such that the prevailing pressure in tank 206 is sufficient to close valve 216 to shut-off the supply of liquid from source 202 and drive the volume of liquid through outlet 214 along outlet pipe 216 to system 204. After tank 206 has been substantially emptied, the level of the liquid therein reaches sensor 230b as shown in Figure 7a. On activation, sensor 230b primes apparatus sp II yly~slur~irr*ollrrY WO 95/14205 PCTIUS94/13469 200 for the next injection of liquid by reducing the prevailing pressure in tank 206 by opening pressure release valve 224 and closing valve 222.

While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.

c II 1

Claims (10)

1. A cleaning system for cleaning the inside of fluid conducting tubing, the cleaning system comprising: a plurality of balls entrained by a fluid flowing through the system; separation apparatus for separating said balls from the fluid downstream of the tubing; accumulator apparatus for accumulating said balls downstream of said separation apparatus; storage apparatus for storing a volume of injection fluid, said storage apparatus being in communication with said accumulator apparatus, said storage apparatus being in communication with a point upstream of the tubing; and a compressor for selectively providing a supply of compressed air into said storage apparatus for injecting a portion of said volume of injection fluid from said storage apparatus to said point, a fraction of said volume of injection fluid passing through said accumulator apparatus for entraining some of said balls therewith for injection upstream of the tubing.

2. The system as in claim 1 wherein said accumulator apparatus and said storage apparatus are combined in a single housing.

3. The system as in claim 2 wherein said housing includes a sieve and a funnel with a downward depending tube.

4. The system as in claim 1 wherein said accumulator apparatus and said storage apparatus are configured as two separate airtight housings. IlgC- I The system as in claim 1 wherein said storage apparatus is at least partly filled by fluid run-off from said accumulator apparatus.

6. The system as in claim 1 further comprising a pressure decreasing device for decreasing the pressure in said storage apparatus.

7. The system as in claim 6 wherein said pressure decreasing device is a release valve.

8. The system as in claim 6 wherein said pressure decreasing device is a pump.

9. The system as in claim I further comprising sensing means for sensing the level of the volume of fluid in said storage apparatus. The system as in claim 1 further comprising a timer for operating the system.

11. A system as claimed in any one of claims 1 to 10 and substantially as hereinbefore described with reference to and/or as shown in any of the Figures of the drawings. DATED this second day of April 1998 C.Q.M. LTD. and MARK M FRIEDMAN Patent Attorneys for the Applicant: F.3. RICE CO. *o 4-" -0 CIO U)9 C-o 00 2z VI. 9 tr9 721 0OL WO 95/14205 WO 9514205PCTIUS94/13469 5/12 28 28 SUBSITUTE SHEET (RULE 26) WO 95/14205 WO 9514205PCT1US94/13469 6/12 28 FIG.3D 28 28 WO 95/14205 WO 9514205PCT/US94/13469 7/12 28 FIG.3G 112 4 4A 11 2A -7 FIG.4 9LZ L 9Z 911 In c~9c 0i 02 0i 911 WO 95/14205 WO 954205PTIUS94/13469 12/12 200 200 202 ITERNATIONAL SEARCH REPORT International application No. PCTIUS94/ 13469 CLASSIFICATION OF SUBJECT MATITER IPC(6) :F280 1/12 US CL :165/95; 15/3.51 According to Internthtional Patent Classification (TPC) or to both national classification and IPC

111. FIELDS SEARCHED Minimum documentation searched (classification systn followed by classification symbols) U.S. 165/95; 15/3.5, 3.51, 104.062 Documentation searched other than minimum documentation to the extent that such documents arc included in the fields searchcd Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, With indication, where appropriate, of the relevant passages Relevant to claim No, Y US, A, 3,919,732 (HONMVA ET AL) 18 November 1975, see 1-10, 32 entire document. Y DE, A, 1,247,359 (ONUKI) 17 August 1967, see entire 1-10, 32 document. Y US, A, 4,620,589 (KOLLER) 4 November 1986, see Figures 11-27 1-4. Y US, A, 4,865,121 (BEN-DOSA) 12 September 1989, see All 11-27 Figures. Y JP, A, 238,397 (SHIMOBAYASHI) 04 October 1988, see All 11-27 Figures. Y US, A, 4,578,838 (PRINZ) 01 April 1986, see All Figures. 29, 31 F'uther documents are listed in the continuation of Box C. ElJ See patent family annex. special categories of cited documnents: inter document published after the internotlonnl filhap dle or priorit documentdefining the general Bate, of the art which ia not considered dari ndl nor teoni th e ivationbucietondradth to be of particular relevance picpeo hoyudryn h neto .X document or particular relevance: the clajitme invention cannot he E' earlier document published on or after the international filing date considered novel or cannot he considered to mitlve un, inventive step document which tony throw doubts on priority claim(s) or which is when the document is taken atone cited to establish the publication date of another citation or other *Y oueto atcla eeactecame neto antb special reason (as apecified)douetopatclrrlvneth isndivnincnote considered to involve an inventive step whieniite dlocumnent is document referring to an oral disclosure. use, exhibition or other combined with one or more other such documntsu, munch combination means being obvious to a person skilled in the art document published priorto the international rilig date but later than documnent member or the sme patent family the priority date claimed Date of the actual complet.ion of the international search Date of mailing of the intetjiational search report 18 JANUARY 1995 13 FEB 1995 Name and mailing addreils of the ISA/US Authorized officer COMmi1116ioner of Patents and Trademarks Box PCT LEONARD R. LEO Washington. D.C. 20231 Facsimile No. NOT APPLICABLE Teleohone No. (703) 305-2611 Form PCT/ISA1210 (second sheet)(July 1992)* ITERNATIONAL SEARCH REPORT International application No. PCT/US94/13469 C (Continuation). DOCUMENTS LONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No, A US, A, 3,978,917 (HONMA ET AL) 07 September 1976, see 1-10, 32 Figure 1. A US, A, 4,569,097 (ECHOLS) 11 Febiruary 1986, see Figure 1, 1-10, 32 A JP, A, 14,190 (SASAKI) 25 January 1982, see All Figures. 1-10, 32 A BE, A, 525,076 (BI'TTERFIELD) 31 December 1953, see Figure 1-10, 32 1. A JP, A, 356,697 (TAKAHATA) 10 December 1992, see All 1-10, 32 Figures. A US, A, 4,544,027 (GOLDBERG) 01 October 1985, see Figure 1. 11-27 A US, A, 5,086,833 (BEN-DOSA) 11 February 1992,see Figure 1. 11-27 Form PCT/ISA1210 (continuation of second shcct)(uly 1992)*