EP0728286B1

EP0728286B1 - Cleaning system for cleaning the inside of fluid conducting tubing and associated apparatus

Info

Publication number: EP0728286B1
Application number: EP95902659A
Authority: EP
Inventors: Moshe Peery
Original assignee: FRIEDMAN Mark M; C Q M Ltd
Current assignee: FRIEDMAN Mark M; C Q M Ltd
Priority date: 1993-11-18
Filing date: 1994-11-18
Publication date: 2001-09-05
Anticipated expiration: 2014-11-18
Also published as: CN1312458A; CN1154834C; EP0728286A4; HU221834B1; CZ143996A3; AU1184795A; KR960706061A; CN1135257A; BR9408567A; KR100346769B1; WO1995014205A1; CZ289247B6; HUT75003A; AU692203B2; PL177797B1; PL314467A1; DE69428207T2; JPH09509244A; HU9601332D0; RU2137999C1

Description

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a cleaning system according to the features of the preamble of claim 1.

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 apparatus 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 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 because 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. A cleaning system as defined in the preamble of claim 1 is known from US-A-3 882 931 or EP-A-148 509.

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 above-mentioned 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 the present invention, a cleaning system for cleaning the inside of fluid conducting tubing, the cleaning system comprising: (a) a plurality of balls entrained by a fluid flowing through the system; (b) separation apparatus for separating the balls from the fluid downstream of the tubing; (c) accumulator apparatus for accumulating the balls downstream of the separation apparatus; characterised by (d) 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 by (e) 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 the accumulator apparatus for entraining some of the balls therewith for injection upstream of the tubing.

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

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

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

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

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

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

The separation apparatus for separating a plurality of balls circulating through fluid conducting tubing having an upstream side and a downstream side, the separation occurring at the downstream side of the tubing, comprises: (a) a conduit having an inlet in flow 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 (b) 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 embodiment of the present invention, the cross-sectional 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 embodiment 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 embodiment of the present invention, the total open area of the sieve is at least approximately five times its cross-sectional area.

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

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

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

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

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

According to a yet still further embodiment of the present invention, the I 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 embodiment 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 recirculation 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 embodiment of the present invention, 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 embodiment of the present invention, the apparatus further comprising first and second valves deployed on the first and second fluid outlets, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1a 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. 1b is a schematic view of the cleaning system of Figure 1a in which the balls are dispersed through the fluid conducting tubing before being trapped in the separation apparatus of the cleaning system;

FIG. 1c is a schematic view of the cleaning system of Figure 1a 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 1 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; and

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.

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 heat-exchangers 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 1a-1c 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 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 10 after each pass of balls 26 through condenser tubing 14.

Separation apparatus

28 delivers balls 26 to ball recirculation apparatus 30 via a 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

valves

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

40 and 42, respectively, which are periodically closed for maintenance and repair purposes of ball recirculation apparatus 30.

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 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 generally 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 the 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 eliciting an environment conducive to the complete evacuation of balls 26 from sieve 58 are described hereinbelow with reference to Figures 3a-3g. First, the cross-sectional 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 58 with a total open area of at least approximately five times its cross-sectional 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-sectional 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 facilitating 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 60 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 70 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 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 80 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 provides 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 recirculation apparatus 30.

An operation cycle of cleaning system 10 will now be explained with reference to Figures 1a-1c. As can be clearly seen, Figure 1a depicts balls 26 accumulated in trap 60 just before their injection upstream of tubing 14, Figure 1b depicts balls 26 dispersed through condenser 12 before being separated from the main flow of fluid by separation apparatus 28 and Figure 1c depicts balls 26 accumulated in separation apparatus 28 before their delivery to ball recirculation apparatus 30.

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 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.

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

30 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 50 toward ball recirculation apparatus 30.

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 50, thereby facilitating their evacuation. However, in certain installations, space requirements do not allow for this arrangement and, therefore, fluid 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 non-perforated portion 98 toward the end of sieve 58 disposed toward ball outlet 50.

Non-perforated portion

98 can extend from a generally semi-trough 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 50.

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 outlet 50.

With reference now to Figures 3d and 3e, sieve 58 can include a non-perforated portion 102 deployed to reduce turbulence within the 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 112b. 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 30. For the sake of clarity, balls 26 entrapped in separation apparatus 112a are 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 from separation apparatus 112b in the same manner. After balls 26b are evacuated, valve 114b is reopened such that separation apparatus 112 reverts back to its normal operation.

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 within the scope of the appended claims.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included just for the sole purpose of increasing intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

A cleaning system for cleaning the inside of fluid conducting tubing (14), the cleaning system comprising:

(a) a plurality of balls (26) entrained by a fluid flowing through the system;

(b) separation apparatus (28; 112, 112A, 112B) for separating the balls from the fluid downstream of the tubing (14); and

(c) accumulator apparatus (60) for accumulating the balls (26) downstream of the separation apparatus (28); characterized by

(d) storage apparatus (62) for storing a volume of injection fluid, the storage apparatus (62) being in communication with the accumulator apparatus (60), the storage apparatus (62) being in communication with a point (74) upstream of the tubing (14); and by

(e) a compressor (64) for selectively providing a supply of compressed air into the storage apparatus (62) for injecting a portion of the volume of injection fluid from the storage apparatus (62) to the point (74), a fraction of the volume of injection fluid passing through the accumulator apparatus (60) for entraining some of the balls (26) therewith for injection upstream of the tubing (14).
The system of claim 1 wherein the separation apparatus (28) includes a generally cylindrical sieve (58) and a ball outlet (50) located substantially in the center of the sieve (58).
The system of claims 1 or 2 wherein the accumulator apparatus (60) and the storage apparatus (62) are combined in a single housing (72).
The system of claims 1 or 2 wherein the accumulator apparatus (60) and the storage apparatus (62) are configured as two separate airtight housings.
The system of one or more of claims 1-4 wherein the accumulator apparatus (60) includes a further sieve (76) and wherein the storage apparatus (62) is at least partly filled by fluid run-off from the accumulator apparatus (60).
The system of one or more of claims 1-5 further comprising a pressure decreasing device (70) for decreasing the pressure in the storage apparatus (62).
The system of claim 6 wherein the pressure decreasing device (70) is a release valve.
The system of claim 6 wherein the the pressure decreasing device (70) is a pump.
The system of one or more of claims 1-8 further comprising sensing means (96b) for sensing the level of the volume of fluid in the storage apparatus (62); or further comprising a timer for operating the system.
The system of claim 1 wherein the separation apparatus (28) includes:

a conduit (44) having an inlet (46) in flow communication with the downstream side of the tubing (14), a ball outlet (50) operatively connected to the accumulator apparatus (60) for recirculating the balls (26) to the upstream side of the tubing (14) and a fluid outlet (48) connected to the upstream side of the tubing (14); and

a generally cylindrical sieve (58) substantially extending lengthwise between the inlet (46) and the ball outlet (50) in the conduit (44) for trapping the plurality of balls (26) therein as fluid continually flows from the inlet (46) to the fluid outlet (48).
The system of claim 10 wherein the cross-sectional area of the inlet (46) is substantially equal to the cross-sectional area of an outlet header neck (18a) of the tubing (14); or wherein the cross-sectional area of the sieve (58) is substantially equal to the cross-sectional area of an outlet header neck (18a) of the tubing (14).
The system of claim 10 wherein the total open area of the sieve (58) is at least approximately five times its cross-sectional area; or wherein the total open area of the sieve (58) is at least approximately five times the cross-sectional area of an outlet header neck (18a) of the tubing (14); or wherein the ball outlet (50) is located substantially center to the sieve (58) .
The system of one or more of claims 10-12 further comprising means (102) for reducing turbulence in the flow of fluid within the vicinity of the fluid outlet (48); or further comprising means (98) for reducing turbulence in the flow of fluid within the vicinity of the ball outlet (50); or further comprising means (104) for urging the plurality of balls (26) toward the ball outlet (50); or further comprising means (106, 108) for compacting the motion of the plurality of balls (50) such that the excursion of the plurality of balls (26) from the axis of the ball outlet (50) is decreased.
The system of one or more of claims 10-12 wherein the sieve (58) includes a non-perforated portion (98, 102); or wherein the sieve (58) converges from the inlet (46) towards the ball outlet (50); or wherein the sieve (58) includes a constricted waist portion (110); or further comprising an insert (104) extending from the ball outlet (50) toward the inlet (46).
The system according to one or more of claims 10-14 further comprising a second separation apparatus (112B) in parallel with the first separation apparatus (112A), the second separation apparatus (112B) including a conduit (44B) having an inlet (46b) in flow communication with the downstream side of the tubing (14), a ball outlet (50B) connected to the inlet of the ball recirculation apparatus and a fluid outlet (48B) connected to an outlet fluid line, and a generally cylindrical sieve (58B) substantially extending between the inlet (46B) and the ball outlet (50B).
The system of claim 15 wherein the inlet (46B) of the second separation apparatus (112B) is substantially opposite the inlet (46A) of the first separation apparatus (112A); or further comprising first and second valves (114A, 114B) deployed on the first and second fluid outlets (48A, 48B), respectively.