Cleaning system for shell and tube heat exchangers

Abstract

A cleaning system for a shell and tube heat exchanger, and has an inlet flowpath an outlet flowpath and a pumping system. The heat exchanger includes first tubes of a first internal diameter, and second tubes of a second internal diameter, different from the first diameter. The inlet flowpath enables introduction of a plurality of cleaning balls into the heat exchanger, and has a first interface configured for engaging with an inlet end of the second tubes. The outlet flowpath enables extraction of the cleaning balls out of the heat exchanger, and has a second interface configured for engaging with an outlet end of the second tubes. The pumping system operates to cause the cleaning balls to be introduced into the heat exchanger via the inlet flowpath and to exit the heat exchanger via the outlet flowpath. The cleaning balls are configured for cleaning the lumens of the second tubes.

Description

[0001] CLEANING SYSTEM FOR SHELL AND TUBE HEAT EXCHANGERS

[0002] TECHNOLOGICAL FIELD

[0003] The presently disclosed subject matter relates to shell and tube heat exchangers, in particular to cleaning systems for shell and tube heat exchangers.

[0004] BACKGROUND

[0005] Shell and tube heat exchangers are well known, and include a bundle or nest of tubes accommodated in a cylindrical housing referred to as a "shell". Tube sheets are provided at each longitudinal end of the tube bundle, and the tube sheets are peripherally joined to the inside of the cylindrical housing. This structure essentially defines two separate flow paths: a tube-side flow path in which a tube side fluid flows through the lumens of the tubes; a shell-side flow path in which a shell side fluid flows in the space between the outside of the tubes and the inside of the cylindrical housing.

[0006] The two fluids are thus kept separate from one another and are not allowed to mix.

[0007] The tube-side flow path is often used for high pressure fluids, while the shell-side flow path is often used for a relatively lower pressure fluid.

[0008] Such shell and tube heat exchangers are commonly used for providing heat exchange between one fluid flowing in the tube-side flow path, and another fluid flowing in the shell-side flow path.

[0009] There are a variety of different examples of such shell and tube heat exchangers, including for example single pass heat exchangers, single pass series heat exchangers, and double pass heat exchangers. In at least some applications, water is commonly used as the fluid that flows through the tube-side flow path. Such applications often suffer from fouling and scaling in the inner surfaces of the tubes, which can result in a reduction in the heat transfer efficiency, an increase in energy consumption, and can also result in corrosion with associated increased maintenance costs and potential downtime.

[0010] One known solution to the fouling and scaling problem is the Automatic Condenser Cleaning System (ACCS) provided by CET Enviro. Essentially, a plurality of balls are periodically caused to flow through the tubes, and the balls operate to rub against the internal walls of the tubes to thereby scrub and rub the walls, preventing buildup of deposits on the tube internal surfaces. The balls are of a diameter matched to be very close to the internal diameter of the tubes to ensure close contact between the balls and the tube internal surfaces. This system is used in heat exchangers in which all the tubes in the tube bundle have the same nominal internal tube diameter.

[0011] There are some types of shell and tube heat exchangers in which, rather than having a single tube bundle in which the tubes all have the same internal tube diameter, the shell and tube heat exchangers each have two bundles of tubes, in which a first bundle has tubes of a first diameter and the second bundle has tubes of a second diameter, and in which the first diameter is greater than the second diameter.

[0012] Current cleaning systems such as for example the aforementioned ACCS system, are not suitable per se for such shell and tube heat exchangers since if large balls are used that are matched to the first diameter, these balls will not be able to enter and clean the second bundle of tubes as the internal diameters are too small for the balls to enter, and which can also lead to blocking of the second bundle tubes. Conversely, if small balls are used that are matched to the second diameter, these balls will not be able to properly rub against and clean the first bundle of tubes as the internal diameters are too large for the balls to form close contact with.

[0013] Conventionally, such types of shell and tube heat exchangers can only be cleaned by first opening the shell and tube heat exchangers, and then manually cleaning each of its components. GENERAL DESCRIPTION

[0014] According to a first aspect of the presently disclosed subject matter, there is provided a cleaning system for a shell and tube heat exchanger (interchangeably referred to herein as "heat exchanger" unless otherwise specified), the heat exchanger including a first tube bundle of first tubes, each said first tube having a respective first tube lumen, and a second tube bundle of second tubes, each said second tube having a respective second lumen, the first lumens each having a first internal diameter, the second lumens each having a second diameter, the second diameter being different from the first diameter, the cleaning system comprising: an inlet flowpath, configured for enabling introduction of a plurality of cleaning balls into the shell and tube heat exchanger, the inlet flowpath having a first interface configured for engaging with an inlet end of said second cluster of second tubes, the first interface configured for: providing free fluid communication between the inlet flowpath and said second cluster of second tubes via an inside of the first interface; providing free fluid communication between an outside of the inlet flowpath within the heat exchange chamber and said second cluster of second tubes via the inside of the first interface; and preventing passage of the balls between the inside of the first interface and the outside of the inlet flowpath within the heat exchange chamber; an outlet flowpath configured for enabling extraction of the cleaning balls out of the shell and tube heat exchanger, the outlet flowpath having a second interface configured for engaging with an outlet end of said second cluster of second tubes, the second interface configured for: providing free fluid communication between the outlet flowpath and said second cluster of second tubes via an inside of the second interface; providing free fluid communication between an outside of the outlet flowpath within the heat exchange chamber and said second cluster of second tubes via the inside of the second interface; and preventing passage of the balls between the inside of the second interface and the outside of the outlet flowpath within the heat exchange chamber; a pumping system configured for selectively causing the cleaning balls to be introduced into the shell and tube heat exchanger via the inlet flowpath and to exit the shell and tube heat exchanger via the outlet flowpath; wherein the cleaning balls are configured for cleaning said second lumens.

[0015] For example, said cleaning balls are incapable of cleaning said first lumens.

[0016] Additionally or alternatively, for example, said inlet flow path comprises an inlet line, a selectively actuable first valve, and a ball collector, wherein the inlet line extends between, and provides fluid communication between, the first interface and the pumping system.

[0017] Additionally or alternatively, for example, said first interface is configured for being affixed to a first sheet of the heat exchanger.

[0018] Additionally or alternatively, for example, said first interface is configured for engaging with respective second tube inlet ends of the second tubes.

[0019] Additionally or alternatively, for example, said first interface comprises a first convex structure defining enclose a first internal volume of the first interface, said first convex structure having a first open end, first outer walls, and an inlet port. For example, said inlet port connects the first interface to the inlet line. Additionally or alternatively, for example, said first open end has a first peripheral lip configured for abutting against, and being affixed to, an outward facing first face of the first sheet. For example, the first peripheral lip is fixable with respect to the first sheet on the outward facing first face of the first sheet. Additionally or alternatively, for example, said first peripheral lip circumscribes a first area on the outward facing first face of the first sheet, wherein said first area is such as to enclose said inlet ends of said second cluster of second tubes, and to concurrently exclude respective first tube inlet ends of the first tubes. Additionally or alternatively, for example, said first outer walls comprise a plurality of first through- holes, wherein said first through-holes provide free fluid communication between an outside of the first outer walls and the first internal volume. For example, the first outer walls are formed from sheets of a contiguous material, and which include the plurality of said first through-holes. Alternatively, said first outer walls are made from a net-like material having a plurality of respective weave threads and weft threads interlinked with one another, and in which the plurality of said first through-holes are formed in respective open areas formed between the weave threads and the weft threads. Additionally or alternatively, for example, said first through-holes each have a characteristic first dimension that is smaller than a nominal diameter of each of the cleaning balls.

[0020] Additionally or alternatively, for example, said outlet flow path comprises an outlet line, and a selectively actuable second valve, wherein the outlet line extends between, and provides fluid communication between, the second interface and the pumping system.

[0021] Additionally or alternatively, for example, said second interface is configured for being affixed to a second sheet of the heat exchanger.

[0022] Additionally or alternatively, for example, said second interface is configured for engaging with respective second tube outlet ends of the second tubes.

[0023] Additionally or alternatively, for example, said second interface comprises a second convex structure defining enclose a second internal volume of the second interface, said second convex structure having a second open end, second outer walls, and an outlet port. For example, said outlet port connects the second interface to the outlet line. Additionally or alternatively, for example, said second open end has a second peripheral lip configured for abutting against, and being affixed to, an outward facing first face of the second sheet. For example, the second peripheral lip is fixable with respect to the second sheet on the outward facing first face of the second sheet. Additionally or alternatively, for example, said second peripheral lip circumscribes a second area on the outward facing first face of the second sheet, wherein said second area is such as to enclose said outlet ends of said second cluster of second tubes, and to concurrently exclude respective second tube inlet ends of the first tubes. Additionally or alternatively, for example, said second outer walls comprise a plurality of second through-holes, wherein said second through-holes provide free fluid communication between an outside of the second outer walls and the second internal volume. For example, the second outer walls are formed from sheets of a contiguous material, and which include the plurality of said second through-holes. Alternatively for example, said second outer walls are made from a net-like material having a plurality of respective weave threads and weft threads interlinked with one another, and in which the plurality of said second through-holes are formed in respective open areas formed between the weave threads and the weft threads. Additionally or alternatively, for example, said second through-holes each have a characteristic second dimension that is smaller than a nominal diameter of each of the cleaning balls.

[0024] Additionally or alternatively, for example, the cleaning system comprises a controller operatively coupled to the first valve, the second valve, and the pumping system.

[0025] Additionally or alternatively, for example, the pumping system is configured for operating to selectively cause a first fluid flow to flow through the inlet flow path in a first direction from the pumping system to the first interface, and for enabling a plurality of said cleaning balls to flow within said first fluid flow. For example, the pumping system is further configured for operating to selectively cause a second fluid flow to flow through the outlet flow path in a second direction from the second interface to the pumping system, and for enabling the plurality of said cleaning balls to flow within said second fluid flow.

[0026] Additionally or alternatively, for example, the heat exchanger is any one of a single pass heat exchanger or a double pass heat exchanger.

[0027] Alternatively, for example, the heat exchanger is a single pass series heat exchanger, comprising a first heat exchanger housing and a second heat exchanger housing, coupled to one another in series, wherein:

[0028] - the first tubes of the first bundle of first tubes each comprises a first tube first part accommodated in the first heat exchanger housing and a first tube second part accommodated in the second heat exchanger housing; the second tubes of the second bundle of second tubes each comprises a second tube first part accommodated in the first heat exchanger housing and a second tube second part accommodated in the second heat exchanger housing;

[0029] - the first heat exchanger housing comprising a respective first sheet joined to the inlet openings of the first tube first parts of the first bundle of first tubes and to the inlet openings of the second tube first parts of the second bundle of first tubes; - the second heat exchanger housing comprising a respective second sheet joined to the outlet openings of the first tube second parts of the first bundle of first tubes and to the outlet openings of the second tube second parts of the second bundle of first tubes;

[0030] - the first heat exchanger housing comprising a respective second sheet joined to the outlet openings of the first tube first parts of the first bundle of first tubes and to the outlet openings of the second tube first parts of the second bundle of first tubes;

[0031] - the second heat exchanger housing comprising a respective first sheet joined to the inlet openings of the first tube second parts of the first bundle of first tubes and to the inlet openings of the second tube second parts of the second bundle of first tubes.

[0032] For example, the cleaning system further comprises a coupling flow path for coupling between the inlet flow path and the outlet flow path, for example wherein: said inlet flow path is configured for selectively enabling introduction of the cleaning balls into the first heat exchanger housing of the heat exchanger; said outlet flow path is configured for selectively enabling exit of the cleaning balls from the second heat exchanger housing of heat exchanger; and said coupling flow path is configured for selectively enabling exit of the cleaning balls from the first heat exchanger housing and subsequent introduction of the cleaning balls into the second heat exchanger housing of heat exchanger.

[0033] Additionally or alternatively, for example, the coupling flow path is configured for selectively enabling passage of the cleaning balls exclusively along a portion of a tube-side flow path between the second tubes of the first heat exchanger housing and the second tubes of the second heat exchanger housing, while concurrently preventing introduction of the sealing balls into another portion of the tube-side flow path corresponding to the first tubes of the second heat exchanger housing, or to the first tubes of the first heat exchanger housing.

[0034] Additionally or alternatively, for example, the coupling flow path couples all of the second tube outlet ends of the respective second tubes of first heat exchanger housing with all of the second tube inlet ends of the respective second tubes of second heat exchanger housing.

[0035] Additionally or alternatively, for example, the coupling flow path includes an outlet interface, a coupling line, and an inlet interface. For example, the coupling line extends between, and provides fluid communication between, the outlet interface and inlet interface. Additionally or alternatively, for example, the outlet interface is configured for engaging with all of the second tube outlet ends of the respective second tubes of first heat exchanger housing, and wherein the inlet interface is configured for engaging with all of the second tube inlet ends of the respective second tubes of second heat exchanger housing. For example, said outlet interface is configured for being affixed onto the respective second sheet of the first heat exchanger housing, and wherein said inlet interface is configured for being affixed onto the respective first sheet of the second heat exchanger housing.

[0036] According to a second aspect of the presently disclosed subject matter, there is provided a heat exchanger comprising a cleaning system as defined herein regarding the first aspect of the presently disclosed subject matter. For example, the heat exchanger further comprises a conventional ball cleaning system configured for cleaning the first tubes. For example, the heat exchanger can be any one of a single pass heat exchanger, a double pass heat exchanger, a single pass series heat exchanger.

[0037] According to a third aspect of the presently disclosed subject matter, there is provided a control system configured to monitor a parameter representative of fouling of the tube side flow path of a shell and tube heat exchanger, and further configured to activate a ball cleaning system with cleaning balls, responsive to the magnitude of the parameter crossing a predetermined threshold.

[0038] For example, the control system comprises a control system controller operatively coupled to a monitoring system. For example, the controller is operatively coupled to the ball cleaning system. Additionally or alternatively, for example, said monitoring system is configured to monitor a level of fouling of the tube side flow path of the shell and tube heat exchanger with respect to one or more fouling parameters.

[0039] For example, a first said fouling parameter is an approach temperature of the heat exchanger, wherein the approach temperature is a difference in temperature between a first temperature at a heat exchanger tube side outlet of the tube side flow path, and a second temperature at a heat exchanger shell side outlet of a shell side flow path of the heat exchanger. For example, said monitoring system includes at least a first temperature sensor configured for monitoring the first temperature at the heat exchanger tube side outlet of the tube side flow path, and a second temperature sensor configured for monitoring the second temperature at heat exchanger shell side outlet of the shell side flow path, and wherein the at least one first temperature sensor and the at least one second temperature sensor are operatively coupled to the control system controller. For example, the at least one first temperature sensor and the at least one second temperature sensor are configured for providing electrical, digital or electronic signals to the control system controller representative of the respective first temperature and second temperature being monitored by the first temperature sensor and the second temperature sensor. Additionally or alternatively, for example, the control system controller is configured for activating the ball cleaning system responsive to the approach temperature exceeding a predetermined threshold temperature.

[0040] Additionally or alternatively, for example, a second said fouling parameter is a level of negative pressure generated at the at a heat exchanger shell side inlet of a shell side flow path of the heat exchanger. For example, the monitoring system includes at least a pressure sensor configured for monitoring a pressure at the heat exchanger shell side inlet, wherein the pressure sensor is operatively coupled to the control system controller. For example, the at least one pressure sensor is configured for providing electrical, digital or electronic signals to the control system controller representative of the pressure being monitored by the pressure sensor. Additionally or alternatively, for example, the control system controller is configured for activating the ball cleaning system, responsive to the pressure exceeding a predetermined threshold pressure.

[0041] Additionally or alternatively, for example, a third said fouling parameter is a pressure difference in the tube side flow path, between a heat exchanger tube side inlet and a heat exchanger tube side outlet of the heat exchanger. For example, the monitoring system includes at least a first pressure sensor configured for monitoring a first pressure at the heat exchanger tube side inlet, and a second pressure sensor, configured for monitoring a second pressure at the heat exchanger tube side outlet, and wherein the first pressure sensor and the second pressure sensor are each operatively coupled to the control system controller. For example, the first pressure sensor and the second pressure sensor are each configured for providing electrical, digital or electronic signals to the control system controller representative of the first pressure being monitored by the first pressure sensor, and the second pressure being monitored by the second pressure sensor. Additionally or alternatively, for example, said control system controller is configured for activating the ball cleaning system, responsive to the pressure difference exceeding a predetermined threshold pressure difference.

[0042] Additionally or alternatively, for example, the ball cleaning system includes the cleaning system as defined herein regarding the first aspect of the presently disclosed subject matter.

[0043] Additionally or alternatively, for example, the ball cleaning system includes a conventional ball cleaning system.

[0044] Additionally or alternatively, for example, the shell and tube heat exchanger can be any one of a single pass heat exchanger, a double pass heat exchanger, a single pass series heat exchanger.

[0045] BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, examples will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0047] Fig- 1 shows in isometric view, a cleaning system according to a first example of the presently disclosed subject matter.

[0048] Fig- 2 shows in isometric view, a heat exchanger according to a first example of the presently disclosed subject matter, comprising the cleaning system example of Fig. 1.

[0049] Fig- 3 shows in cross-sectional side view the example of Fig. 2, taken along section A-A.

[0050] Fig. 4 shows in front view a first sheet of the heat exchanger example of Fig. 2.

[0051] Fig. 5 shows in rear view a second sheet of the heat exchanger example of Fig. 2. Fig- 6 shows in isometric view an example of an inlet interface of the cleaning system example of Fig. 2.

[0052] Fig- 7 shows in isometric view, a heat exchanger according to a second example of the presently disclosed subject matter, comprising a geometrical variation of the cleaning system example of Fig. 1.

[0053] Fig- 8 shows in cross-sectional side view the example of Fig. 7, taken along section B-B.

[0054] Fig. 9 shows in front view a first sheet of the heat exchanger example of Fig. 7.

[0055] Fig. 10 shows in rear view a second sheet of the heat exchanger example of Fig. 7.

[0056] Fig. 11 shows in isometric view the cleaning system example of Fig. 7.

[0057] Fig. 12 shows in isometric view, a heat exchanger according to a third example of the presently disclosed subject matter, comprising a cleaning system according to a second example of the presently disclosed subject matter.

[0058] Fig. 13 shows in cross-sectional side view the example of Fig. 12, taken along section C-C.

[0059] Fig. 14 shows in isometric view the cleaning system example of Fig. 12.

[0060] Fig. 15 schematically illustrates a first example of a control system according to the second aspect of the presently disclosed subject matter, operatively coupled to an example of a heat exchanger.

[0061] DETAILED DESCRIPTION

[0062] Referring to Fig. 1, a first example of cleaning system for a shell and tube heat exchanger according to a first aspect of the presently disclosed subject matter, is generally designated 100, and comprises an inlet flow path 200, and outlet flow path 300 and a pumping system 500.

[0063] In the first example, and referring to Figs. 2, 3, 4, 5, 6, the shell and tube heat exchanger, generally designated with reference numeral 600, is a single pass heat exchanger, and comprises a heat exchanger housing 650 (also referred to interchangeably herein as a shell) defining a heat exchange chamber 655. The heat exchange chamber 650 accommodates a first tube bundle of first tubes 660, and a second tube bundle of second tubes 680.

[0064] The heat exchanger housing 650 comprises a nominally cylindrical central portion 656, and two longitudinal ends 654, 658, each joined to the central portion 656 at opposite longitudinal ends thereof.

[0065] Referring in particular to Fig. 3 and Fig. 4, the first tubes 660 each have a respective first internal diameter DI, while the second tubes 680 each have a respective second diameter, D2.

[0066] The second diameter D2 is different from the first diameter DI. In at least this example, the second diameter D2 is smaller than the first diameter DI. However, in at least some alternative variations of this example, the second diameter D2 is greater than the first diameter DI.

[0067] Each first tube 660 has a respective open first tube inlet end 662 at a first longitudinal end thereof, a respective open first tube outlet end 664 at a second longitudinal end thereof, and a respective first lumen 665 extending between the first tube inlet end 662 and the first tube outlet end 664; there is open fluid communication between the first tube inlet end 662 and the first tube outlet end 664 via the first lumen 665.

[0068] Each second tube 680 has a respective open second tube inlet end 682 at a first longitudinal end thereof, a respective open second tube outlet end 684 at a second longitudinal end thereof, and a respective second lumen 685 extending between the second tube inlet end 682 and the second tube outlet end 684; there is open fluid communication between the second tube inlet end 682 and the second tube outlet end 684 via the second lumen 685.

[0069] A first sheet 672 is provided at a first longitudinal end of the first tubes 660 and the second tubes 680. The first sheet 672 is peripherally joined to the inside of the heat exchanger housing 650, in particular at one longitudinal end of the central portion 656. The first sheet 672 comprises a first plurality of holes, each of which is joined to a first tube inlet end 662 of a respective first tube 660, and further comprises a second plurality of holes, each of which is joined to a second tube inlet end 682 of a respective second tube 680. The first sheet 672 has an outward facing first face 671, and an inward facing first face 673. The first sheet 672 is connected at the perimeter of the outward facing first face 671 to the first longitudinal end 654.

[0070] A second sheet 674 is provided at a second longitudinal end of the first tubes 660 and the second tubes 680. The second sheet 674 is peripherally joined to the inside of the heat exchanger housing 650, in particular at the other longitudinal end of the central portion 656. The second sheet 674 comprises a first plurality of holes, each of which is joined to a first tube outlet end 664 of a respective first tube 660, and further comprises a second plurality of holes, each of which is joined to a second tube outlet end 684 of a respective second tube 680. The second sheet 674 has an outward facing second face 676, and an inward facing second face 677. The second sheet 674 is connected at the perimeter of the outward facing second face 676 to the second longitudinal end 658.

[0071] The heat exchange chamber 655 is thus divided into three zones, or volumes, by the first sheet 672 and the second sheet 674: a first zone ZN1 (or first volume), defined between the outward facing first face 671 and the inside of the first longitudinal end 654; a second zone ZN2 (or second volume), defined between the outward facing second face 676 and the inside of the second longitudinal end 658; a third zone ZN3 (or third volume), defined between the inward facing first face 673 and the inward facing second face 677.

[0072] A tube-side flow path TS is defined in which a tube side fluid TF flows between the first zone ZN1 and the second zone ZN2 via the lumens of the tubes 640, 680. A shell-side flow path SS is defined in which a shell side fluid SF flows in the space SP between the outside of the first tubes 660 and of the second tubes 680, and the inside of the heat exchanger housing 650 between the inside facing first face 673 of the first sheet 672 and the inside facing second face 677 of second sheet 674, i.e., within the third zone ZN3.

[0073] The tube side fluid TF and the shell side fluid SF are thus kept separate from one another in the heat exchanger 600, and the two fluids are not allowed to mix with one another.

[0074] For example, the tube-side flow path TS can be used for high pressure fluids, while the shell-side flow path SS can be used for a relatively lower pressure fluid.

[0075] The shell and tube heat exchanger 600 can thus be used for providing heat exchange between a tube side fluid TF flowing in the tube-side flow path TS, and another shell side fluid SF flowing in the shell-side flow path SS.

[0076] The heat exchanger 600, in particular the tube-side flow path TS, comprises a tube side inlet 612 and a tube side outlet 614, each in fluid communication with the first lumens 665 and the second lumens 685. The tube side inlet 612 is provided in the first longitudinal end 654 and opens into, and is in fluid communication with, the first zone ZN1. The tube side outlet 614 is provided in the second longitudinal end 658 and opens into, and is in fluid communication with, the second zone ZN2. In operation of the heat exchanger 600 the tube side fluid TF is caused to flow, essentially axially, from the tube side inlet 612 to the tube side outlet 614 via the first lumens 665 and the second lumens 685.

[0077] The heat exchanger 600, in particular the shell-side flow path SS, comprises a shell side inlet (not shown) and a tube side outlet (not shown), each in fluid communication with the inside space SP. In operation of the heat exchanger 600 the shell side fluid SF is caused to flow from the shell side inlet to the shell side outlet via the space SP.

[0078] In at least this example, the heat exchanger 600 optionally comprises a conventional ball cleaning system 900, installed for enabling cleaning of the first bundle of first tubes 660. For example, conventional ball cleaning system 900 can be an Automatic Condenser Cleaning System (ACCS) provided by CET Enviro. The conventional ball cleaning system 900 provides a plurality of first cleaning balls CB1, which are introduced into the tube-side flow path TS from a first ball collector 920 via inlet tubing 930 that opens into the tube side inlet 612, when urged by pump 950. The first cleaning balls CB1 thus pass into the tube side inlet 612 and into the first tubes 660 via the respective tube inlets 662, through the respective first lumens 665, and out of the respective first tube outlets 664, and are collected at the tube side outlet 614 and rerouted back to the ball collector 920 via outlet tubing 940.

[0079] The first cleaning balls CB1 have a nominal diameter DB1, which is nominally complementary to the inside diameter DI of the first tubes 660, such that as the first cleaning balls CB1 are caused to flow in the first tubes 660 in operation of the conventional ball cleaning system 900, the first cleaning balls CB1 clean the inside of the first tubes 660.

[0080] In at least this example, and referring in particular to Fig. 1, the inlet flow path 200 of the cleaning system 100 is configured for selectively enabling introduction of a plurality of second cleaning balls CB2 into the heat exchanger 600.

[0081] Furthermore, in at least this example, the outlet flow path 300 of the cleaning system 100 is configured for selectively enabling exit of the plurality of second cleaning balls CB2 from the heat exchanger 600, having first been introduced into the heat exchanger 600 via the inlet flow path 200.

[0082] The second cleaning balls CB2 have a nominal diameter DB2, which is nominally complementary to the inside diameter D2 of the second tubes 680, such that as the second cleaning balls CB2 are caused to flow in the second tubes 680 in operation of the cleaning system 100, the second cleaning balls CB2 clean the inside of the second tubes 680.

[0083] In particular, the inlet flow path 200 of the cleaning system 100 is configured for selectively enabling introduction of a plurality of second cleaning balls CB2 exclusively into a portion of the tube-side flow path TS corresponding to the second tubes 680, while concurrently preventing introduction of the second sealing balls CB2 into another portion of the tube-side flow path TS corresponding to the first tubes 660.

[0084] The inlet flow path 200 includes an inlet interface 220, an inlet line 240, a selectively actuable first valve 230, and a ball collector 260. The inlet interface 220 is configured for engaging with all of the second tube inlet ends 682 of the respective second tubes 680, and the inlet line 240 extends between, and provides fluid communication between, the inlet interface 220 and the pumping system 500.

[0085] The inlet line 240 is in the form of tubing having an internal diameter significantly greater than the diameter DB2 of the second cleaning balls CB2, to enable the second cleaning balls CB2 to flow freely in the inlet line 240 under the action of the pumping system 500.

[0086] The first valve 230 is provided in the inlet line 240, and in at least this example is electrically actuable between an open position, in which fluid flow (including the flow of said second cleaning balls CB2) through the inlet line 240 is permitted, and a closed position, in which fluid flow (including the flow of said second cleaning balls CB2) through the inlet line 240 is blocked.

[0087] The first valve 230 is operatively coupled to a controller 290, that controls operation of the first valve 230.

[0088] The inlet interface 220 is configured for: providing free fluid communication between the inlet flow path 200 and all of the second cluster of second tubes 680, in particular the respective second tube inlet ends 682 thereof; providing free fluid communication between the first zone ZN1 outside of the inlet flow path 200 and the second cluster of second tubes 680; and preventing passage of the second cleaning balls CB2 between an inside of the first interface 220 and the outside of the inlet flow path 200 within the first zone ZN1 of the heat exchange chamber 655.

[0089] In at least this example, and referring in particular to Fig. 6, the inlet interface 220 is in the form of a box or other convex structure, having an open end 221, outer walls 222, and inlet port 223.

[0090] The inlet port 223 connects the inlet interface 220 to the inlet line 240.

[0091] The open end 221 has a first peripheral lip 224 configured for abutting against, and being affixed to, the outward facing first face 671 of the first sheet 672. For example, the peripheral lip 224 can optionally include a flange that is boltable or otherwise fixable with respect to the first sheet 672 on the outward facing first face 671 thereof.

[0092] Referring also to Fig. 4, the first peripheral lip 224 circumscribes a first area Al on the outward facing first face 671.

[0093] The first area Al is such as to enclose the second tube inlet ends 682 of all the second tubes 680, and to concurrently exclude the first tube inlet ends 662 of the first tubes 660.

[0094] The outer walls 222 enclose a first internal volume IV1, and comprise a plurality of through-holes 229 that provide free fluid communication between an outside of the outer walls 222 and the first internal volume IV1. For example, the outer walls 222 can be formed from flat or curved or molded sheets of a contiguous material, and which include the plurality of through-holes 229. Alternatively, for example, the outer walls 222 are made from a net-like material having a plurality of weave threads and weft threads interlinked with one another, and in which the plurality of through-holes 229 are formed in the open areas formed between the weave threads and the weft threads.

[0095] Referring again to Fig. 6, the through-holes 229 each have a characteristic first dimension DO, for example a diameter or minimum dimension of each through-hole 229.

[0096] The first dimension DO is smaller than the nominal diameter DB2 of each of the second cleaning balls CB2.

[0097] The plurality of through-holes 229 provide an aggregate open area for the inlet interface 220 through which fluid can flow. This aggregate open area can be larger than the remaining solid wall of the inlet interface 220 through which fluid cannot flow, or can be equal thereto or less than the remaining solid wall of the inlet interface 220. Thus, the number of through-holes 229 in the inlet interface 220 can be chosen to enable a desired flow to pass through the inlet interface 220 during cleaning operation.

[0098] Thus, once the second cleaning balls CB2 are in the first internal volume IV1 (delivered thereto via the inlet flow path 200), they cannot pass through the outer walls 222 and into the outside of the outer walls 222 in the first zone ZN1. Concurrently, the first cleaning balls CB1, which have a nominal diameter DB1 also greater than the first dimension DI, cannot pass from the outside of the outer walls 222 in the first zone ZN1, and thus are prevented from entering into the first internal volume IV1 via the outer walls 222.

[0099] Thus, the first interface 220, via the holes 229, allows free fluid flow therethrough (i.e., through the walls 222 thereof), but prevents the first balls CB1 and the second balls CB2 passing therethrough (i.e., through the walls 222 thereof), thereby separating the first balls CB1 from the second balls CB2.

[0100] In particular, the outlet flow path 300 of the cleaning system 100 is configured for selectively enabling removal of the plurality of second cleaning balls CB2 exclusively from a portion of the tube-side flow path TS corresponding to the second tubes 680, while concurrently preventing introduction of the second sealing balls CB2 into another portion of the tube-side flow path TS corresponding to the first tubes 660.

[0101] Referring in particular to Fig. 1, the outlet flow path 300 includes an outlet interface 320, an outlet line 340, and a selectively actuable valve 330.

[0102] The outlet interface 320 is configured for engaging with all of the second tube outlet ends 684 of the respective second tubes 680, and the outlet line 340 extends between, and provides fluid communication between, the outlet interface 320 and the pumping system 500, via the ball collector 260.

[0103] The outlet line 340 is in the form of tubing having an internal diameter significantly greater than the diameter DB2 of the second cleaning balls CB2, to enable the second cleaning balls CB2 to flow freely in the outlet line 340 under the action of the pumping system 500.

[0104] The second valve 330 is provided in the outlet line 340, and in at least this example is electrically actuable between an open position, in which fluid flow (including the flow of said second cleaning balls CB2) through the outlet line 340 is permitted, and a closed position, in which fluid flow (including the flow of said second cleaning balls CB2) through the outlet line 340 is blocked.

[0105] The second valve 330 is operatively coupled to the controller 290, that controls operation of the second valve 330. The outlet interface 320 is configured for: providing free fluid communication between the outlet flow path 300 and all of the second cluster of second tubes 680, in particular the respective second tube outlet ends 684 thereof; providing free fluid communication between the second zone ZN2 outside of the outlet flow path 300 and the second cluster of second tubes 680; and preventing passage of the second cleaning balls CB2 between an inside of the outlet interface 320 and the outside of the outlet flow path 300 within the second zone ZN2 of the heat exchange chamber 655.

[0106] In at least this example, the outlet interface 320 is similar to the inlet interface 220, mutatis mutandis, and similarly is in the form of a box or other convex structure, having an open end 321, outer walls 322, and outlet port 323.

[0107] The outlet port 323 connects the outlet interface 320 to the outlet line 340.

[0108] The open end 321 has a second peripheral lip 324 configured for abutting against, and being affixed to, the outward facing first face 676 of the second sheet 674. For example, the second peripheral lip 324 can optionally include a flange that is boltable or otherwise fixable with respect to the second sheet 674 on the outward facing first face 676.

[0109] Referring in particular to Fig. 5, the second peripheral lip 324 circumscribes a second area A2 on the outward facing first face 676.

[0110] The second area A2 is such as to enclose the second tube outlet ends 684 of all the second tubes 680, and to concurrently exclude the first tube outlet ends 664 of the first tubes 660.

[0111] The outer walls 322 enclose a second internal volume IV2, and comprise a plurality of through-holes 329 that provide free fluid communication between an outside of the outer walls 322 and the second internal volume IV2. For example, the outer walls 322 can be formed from flat or molded sheets of a contiguous material, and which include the plurality of through-holes 329. Alternatively, for example, the outer walls 322 are made from a net-like material having a plurality of weave threads and weft threads interlinked with one another, and in which the plurality of through-holes 329 are formed in the open areas formed between the weave threads and the weft threads.

[0112] The through-holes 329 each have a characteristic second dimension DOO, for example a diameter or minimum dimension of each through-hole 329.

[0113] The second dimension DOO is smaller than the nominal diameter DB2 of each of the second cleaning balls CB2.

[0114] In at least this example, the first dimension DO and the second dimension DOO are nominally equal to one another.

[0115] The plurality of through-holes 329 provide an aggregate open area for the outlet interface 320 through which fluid can flow. This aggregate open area can be larger than the remaining solid wall of the outlet interface 320 through which fluid cannot flow, or can be equal thereto or less than the remaining solid wall of the outlet interface 320. Thus, the number of through-holes 329 in the outlet interface 320 can be chosen to enable a desired flow to pass through the outlet interface 320 during cleaning operation.

[0116] Thus, once the second cleaning balls CB2 are in the second internal volume IV2 (having been delivered thereto via the second tubes 680), they cannot pass through the outer walls 322 and into the outside of the outer walls 322 in the second zone ZN2.

[0117] Concurrently, the first cleaning balls CB1, which have a nominal diameter DB1 greater than the second dimension DOO, cannot pass from the outside of the outer walls 322 in the second zone ZN2, and thus are prevented from entering into the second internal volume IV2 via the outer walls 322.

[0118] Thus, the second interface 320, via the holes 329, allows free fluid flow therethrough (i.e., through the walls 322 thereof), but prevents the first balls CB1 and the second balls CB2 passing therethrough (i.e., through the walls 322 thereof), thereby separating the first balls CB1 from the second balls CB2.

[0119] The ball collector 260 is provided in the inlet line 240, between the inlet interface 220 and the pumping system 500, and in at least this example between the first valve 230 and the pumping system 500. The ball collector 260 is also provided in the outlet line 340, between the outlet interface 320 and the pumping system 500, and in at least this example between the second valve 330 and the pumping system 500.

[0120] Thus the inlet line 240 and the outlet line 340 are in selective fluid communication with one another via the ball collector 260 and pumping system 500.

[0121] The ball collector 260 operates as a reservoir for the second cleaning balls CB2, and thus has a volumetric capacity to accommodate the plurality of second cleaning balls CB2.

[0122] The ball collector 260 is thus in fluid communication with the pumping system 500 and the inlet interface 220 via the inlet line 240 and first valve 230. Under the action of the pumping system 500 (and when the first valve 230 is open, and the second valve 330 is closed), for example under positive pressure generated by the pumping system 500, enables the plurality of second cleaning balls CB2 to be delivered to the inlet interface 220.

[0123] Similarly, the ball collector 260 is also in fluid communication with the pumping system 500 and the outlet interface 320 via the outlet line 340 and second valve 330. Under the action of the pumping system 500 (and when the second valve 330 is open, and the first valve 230 is closed), for example under negative (suction) pressure generated by the pumping system 500, enables the plurality of second cleaning balls CB2 to be received from the outlet interface 320.

[0124] The ball collector 260 is in fluid communication with the pumping system 500, selectively allowing working fluid to be pumped from the pumping system 500 and through the ball collector 260 in first direction towards the inlet interface 220, and selectively allowing working fluid to be pumped to the pumping system 500 through the ball collector 260 in a second direction (opposite to the first direction) from the outlet interface 320. The ball collector 260 also includes a net, trap, or other filtering arrangement at a longitudinal end thereof closest to the pumping system 500, to prevent the second cleaning balls CB2 from passing from the ball collector 260 to the pumping system 500. The pumping system 500 includes any suitable pump that can be operated to selectively provide a desired fluid flow in each one of the two directions through the pumping system 500 - in a first direction from the pump towards the inlet interface 220 in the inlet flow path 200, and in a second direction (opposite to the first direction) towards the pumping system 500 from the outlet interface 320 in the outlet flow path 300.

[0125] The cleaning system 100 is thus coupled to the heat exchanger 600 by engaging or otherwise affixing the inlet interface 220 to the outward facing first face 671 of the first sheet 672 via the open end 221, and such that the first peripheral lip 224 circumscribes the first area Al on the outward facing first face 671. In other words, the inlet interface 220 is affixed to the first sheet 672 in a manner to enclose therein the second tube inlet ends 682 of all the second tubes 680, and to concurrently exclude the first tube inlet ends 662 of the first tubes 660. Similarly, coupling of the cleaning system 100 to the heat exchanger 600 is further accomplished by engaging or otherwise affixing the outlet interface 320 to the outward facing second face 676 of the second sheet 674 via the open end 321, and such that the second peripheral lip 324 circumscribes the second area A2 on the outward facing first face 676. In other words, the outlet interface 320 is affixed to the second sheet 674 in a manner to enclose therein the second tube outlet ends 684 of all the second tubes 680, and to concurrently exclude the first tube outlet ends 664 of the first tubes 660.

[0126] Thus, when required or desired to operate the cleaning system 100 to clean the second tubes 680 of the heat exchanger 600, the controller 290 operates to close the second valve 330 and to concurrently open the first valve 230. At this point the second cleaning balls CB2 are accommodated in the ball collector 260.

[0127] The controller 290 then operates the pumping system 500 to cause a fluid flow to flow in the first direction through the inlet flow path 200 and towards the inlet interface 220, carrying the second cleaning balls CB2 with the fluid flow. Thereafter, continued pumping action by the pumping system 500 urges the second cleaning balls CB2 to flow through the second tubes 680, thereby cleaning the inside surfaces of the second tubes 680, and the second cleaning balls essentially collect at the outlet interface 320, while the fluid flow continues into the second zone ZN1 and thereafter through the outlet port 614. When all the cleaning balls are accumulated at the outlet interface 320, for example after a predetermined period of time in which the pumping system 500 is operating in the first direction, the controller 290 operates to open the second valve 330 and to concurrently close the first valve 230.

[0128] The controller 290 then operates the pumping system 500 to cause a fluid flow to flow in the second direction through the outlet flow path 300 and from the outlet interface 320, carrying the second cleaning balls CB2 with the fluid flow, towards the pumping system 500 and the ball collector 260. Thereafter, pumping action by the pumping system 500 continues until all the second cleaning balls CB2 are collected at the ball collector 260, for example after a predetermined period of time in which the pumping system 500 is operating in the second direction.

[0129] For example, the cleaning system 100 can be configured for operating according to a fixed schedule, for example in which the cleaning system 100 operates to clean the second tubes 680 in periodic intervals, wherein such intervals can be for example, once every 30 minutes.

[0130] Alternatively, for example, the cleaning system 100 can be configured for operating according to predetermined conditions indicative of a level of fouling having exceeded a predetermined threshold, for example according to the second aspect of the presently disclosed subject matter.

[0131] Optionally, the controller 290 can be operatively connected to the conventional ball cleaning system 900, and can be configured to activate operation of the conventional ball cleaning system 900 concurrently with activating operation of the ball cleaning system 100, or according to a different schedule.

[0132] The cleaning system 100 according to the first example can also be used with, and coupled to, other types of shell and tube heat exchangers.

[0133] For example, referring to Fig. 7 and Fig. 8, an example of such a shell and tube heat exchanger, generally designated with reference numeral 600", is a double pass heat exchanger, and comprises a heat exchanger housing 650" (also referred to interchangeably herein as a shell) defining a heat exchange chamber 655". The heat exchange chamber 650" accommodates a first tube bundle of first tubes 660", and a second tube bundle of second tubes 680".

[0134] The heat exchanger housing 650" comprises a nominally cylindrical central portion 656", and two longitudinal ends 654", 658", each joined to the central portion 656" at opposite longitudinal ends thereof.

[0135] Referring in particular to Fig. 9 and Fig. 10, the first tubes 660" each have a respective first internal diameter DI, while the second tubes 680" each have a respective second diameter, D2, similar to the single pass heat exchanger example of Figs. 4 and 5, mutatis mutandis.

[0136] The second diameter D2 is different from the first diameter DI. In at least this example, the second diameter D2 is smaller than the first diameter DI. However, in at least some alternative variations of this example, the second diameter D2 is greater than the first diameter DI.

[0137] Each first tube 660" has a respective open first tube first end 662" at a first longitudinal end thereof, a respective open first tube second end 664" at a second longitudinal end thereof, and a respective first lumen 665" extending between the first tube first end 662" and the first tube second end 664" ; there is open fluid communication between the first tube first end 662" and the first tube second end 664" via the first lumen 665".

[0138] Each second tube 680" has a respective open second tube first end 682" at a first longitudinal end thereof, a respective open second tube second end 684" at a second longitudinal end thereof, and a respective second lumen 685" extending between the second tube first end 682" and the second tube second end 684"; there is open fluid communication between the second tube first end 682" and the second tube second end 684" via the second lumen 685".

[0139] Referring also to Fig. 9, a first sheet 672" is provided at a first longitudinal end of the first tubes 660" and the second tubes 680". The first sheet 672" is peripherally joined to the inside of the heat exchanger housing 650", in particular at one longitudinal end of the central portion 656". The first sheet 672" comprises a first plurality of holes, each of which is joined to a first tube first end 662" of a respective first tube 660", and further comprises a second plurality of holes, each of which is joined to a second tube first end 682" of a respective second tube 680". The first sheet 672" has an outward facing first face 671", and an inward facing first face 673". The first sheet 672" is connected at the perimeter of the outward facing first face 671" to the first longitudinal end 654".

[0140] A divider plate 675" (Fig. 8) can optionally be provided, joined to the first sheet 672", and projects outwardly in a nominally orthogonal manner from the outward facing first face 671". The divider plate 675" extends to and is also sealingly joined to the inside of the inside of the heat exchanger housing 650", in particular to the inside of the longitudinal end 654". The divider plate 675" thus essentially divides the first sheet 675" into two portions: a first sheet portion 672A" and a second sheet portion 672B".

[0141] In at least this example, the first sheet portion 672A" includes a portion of the plurality of first tube first ends 662", while the second sheet portion 672B" includes the remainder of the first tube first ends 662" of the plurality of first tubes 660, plus, all of the second tube first ends 682" of the plurality of second tubes 680". Such a separation ensures that the flow area provided in the first sheet portion 672A" by the summation of the portion of the plurality of first tube first ends 662" is about the same as the flow area provided in the second sheet portion 672B" by the summation of the remainder of the first tube first ends 662" and the summation of second tube first ends 682" of the plurality of second tubes 680"

[0142] A first area Al" can be defined on the outward facing first face 671" such as to enclose the second tube first ends 682" of all the second tubes 680", and to concurrently exclude the first tube first ends 662" of all the first tubes 660".

[0143] Referring also to Fig. 10, a second sheet 674" is provided at a second longitudinal end of the first tubes 660" and the second tubes 680" . The second sheet 674" is peripherally j oined to the inside of the heat exchanger housing 650" , in particular at the other longitudinal end of the central portion 656". The second sheet 674" comprises a first plurality of holes, each of which is joined to a first tube second end 664" of a respective first tube 660", and further comprises a second plurality of holes, each of which is joined to a second tube second end 684" of a respective second tube 680". The second sheet 674" has an outward facing second face 676", and an inward facing second face 677". The second sheet 674" is connected at the perimeter of the outward facing second face 676" to the second longitudinal end 658". A second area A2" can be defined on the outward facing second face 676" such as to enclose the second tube second ends 684" of all the second tubes 680", and to concurrently exclude the first tube second ends 664" of all the first tubes 660".

[0144] The heat exchange chamber 655" is thus divided into four zones, or volumes, by the first sheet 672" and the second sheet 674": a first zone ZN1" (or first volume), defined between the respective outward facing second face portion of the first sheet portion 672B" and the corresponding portion of the inside of the first longitudinal end 654"; a second zone ZN2" (or second volume), defined between the outward facing first face portion of the second sheet portion 672A" and the corresponding portion of the inside of the first longitudinal end 654"; a third zone ZN3" (or third volume), defined between the inward facing first face 673" and the inward facing second face 677"; a fourth zone ZN4" (or fourth volume), defined between the outward facing second face 676" of the second sheet 674" and the inside of the second longitudinal end 658".

[0145] A tube-side flow path TS is defined in which a tube side fluid TF flows between the first zone ZN1 and the second zone ZN2, via the lumens of the tubes 640", 680" and via the fourth zone ZN4".

[0146] A shell-side flow path SS is defined in which a shell side fluid SF flows in the space SP between the outside of the first tubes 660" and of the second tubes 680", and the inside of the heat exchanger housing 650" between the inside facing first face 673 of the first sheet 672" and the inside facing second face 677" of second sheet 674", i.e., within the third zone ZN3.

[0147] The tube side fluid TF and the shell side fluid SF are thus kept separate from one another in the heat exchanger 600", and the two fluids are not allowed to mix with one another.

[0148] For example, the tube-side flow path TS can be used for high pressure fluids, while the shell-side flow path SS can be used for a relatively lower pressure fluid. The shell and tube heat exchanger 600" can thus be used for providing heat exchange between a tube side fluid TF flowing in the tube-side flow path TS, and another shell side fluid SF flowing in the shell-side flow path SS.

[0149] The heat exchanger 600", in particular the tube-side flow path TS, comprises a tube side inlet 612" and a tube side outlet 614", provided at the first longitudinal end 654"

[0150] The tube side inlet 612" opens into, and is in open fluid communication with, the first zone ZN1", while the tube side outlet 614" opens into, and is in open fluid communication with, the second zone ZN2".

[0151] Thus, the tube side inlet 612" is in open fluid communication with the first sheet portion 672A" and the aforesaid portion of the plurality of first tube first ends 662". The tube side outlet 614" is in open fluid communication with the second sheet portion 672B" and the remainder of the first tube first ends 662" of the plurality of first tubes 660, plus, all of the second tube first ends 682" of the plurality of second tubes 680".

[0152] In operation of the heat exchanger 600" the tube side fluid TF is caused to flow from the tube side inlet 612" to the tube side outlet 614", first via the first lumens 665" of the portion of the first tubes 660" in the first zone ZN1", then via the fourth zone ZN4, then via the first lumens 665" of the remainder of the first tubes 660" and the second lumens 685" in the second zone ZN2". Thus, the tube side fluid TF essentially does a U- turn at the fourth zone ZN4".

[0153] The heat exchanger 600", in particular the shell-side flow path SS, comprises a shell side inlet (not shown) and a tube side outlet (not shown), each in fluid communication with the inside space SP. In operation of the heat exchanger 600" the shell side fluid SF is caused to flow from the shell side inlet to the shell side outlet via the space SP.

[0154] In at least this example, the heat exchanger 600" optionally comprises a conventional ball cleaning system 900", for example similar to the conventional ball cleaning system 900 of the first example, mutatis mutandis, installed for enabling cleaning of the first bundle of first tubes 660". For example, conventional ball cleaning system 900" can be an Automatic Condenser Cleaning System (ACCS) provided by CET Enviro.

[0155] The first cleaning balls CB1 have a nominal diameter DB1, which is nominally complementary to the inside diameter DI of the first tubes 660", such that as the first cleaning balls CB1 are caused to flow in the first tubes 660" in operation of the conventional ball cleaning system 900", the first cleaning balls CB1 clean the inside of the first tubes 660".

[0156] Referring to Fig. 1, Fig. 7, Fig. 8, Fig. 9 and Fig. 10, the cleaning system 100 can be coupled to the heat exchanger 600" by engaging or otherwise affixing the inlet interface 220 to the outward facing first face 671" of the first sheet 672" (in particular, to the second sheet portion 672B") via the open end 221, and such that the first peripheral lip 224 circumscribes the first area Al" on the outward facing first face 671". In other words, the inlet interface 220 is affixed to the first sheet 672" (in particular, to the second sheet portion 672B") in a manner to enclose therein the second tube first ends 682" of all the second tubes 680", and to concurrently exclude the first tube first ends 662" of all the first tubes 660". Similarly, coupling of the cleaning system 100 to the heat exchanger 600" is further accomplished by engaging or otherwise affixing the outlet interface 320 to the outward facing second face 676" of the second sheet 674" via the open end 321, and such that the second peripheral lip 324 circumscribes the second area A2" on the outward facing first face 676". In other words, the outlet interface 320 is affixed to the second sheet 674" in a manner to enclose therein the second tube second ends 684" of all the second tubes 680", and to concurrently exclude the first tube second ends 664" of the first tubes 660".

[0157] Thus, when required or desired to operate the cleaning system 100 to clean the second tubes 680" of the heat exchanger 600", the controller 290 operates to close the second valve 330 and to concurrently open the first valve 230. At this point the second cleaning balls CB2 are accommodated in the ball collector 260.

[0158] The controller 290 then operates the pumping system 500 to cause a fluid flow to flow in the first direction through the inlet flow path 200 and towards the inlet interface 220, carrying the second cleaning balls CB2 with the fluid flow. Thereafter, continued pumping action by the pumping system 500 urges the second cleaning balls CB2 to flow through the second tubes 680", thereby cleaning the inside surfaces of the second tubes 680", and the second cleaning balls essentially collect at the outlet interface 320", while the fluid flow continues into the fourth zone ZN4" and thereafter through the outlet port 614"

[0159] When all the cleaning balls CB2 are accumulated at the outlet interface 320, for example after a predetermined period of time in which the pumping system 500 is operating in the first direction, the controller 290 operates to open the second valve 330 and to concurrently close the first valve 230.

[0160] The controller 290 then operates the pumping system 500 to cause a fluid flow to flow in the second direction through the outlet flow path 300 and from the outlet interface 320, carrying the second cleaning balls CB2 with the fluid flow, towards the pumping system 500 and the ball collector 260. Thereafter, pumping action by the pumping system 500 continues until all the second cleaning balls CB2 are collected at the ball collector 260, for example after a predetermined period of time in which the pumping system 500 is operating in the second direction.

[0161] For example, the cleaning system 100 can be configured for operating according to a fixed schedule, for example in which the cleaning system 100 operates to clean the second tubes 680" in periodic intervals, wherein such intervals can be for example, once every 30 minutes.

[0162] Alternatively, for example, the cleaning system 100 can be configured for operating according to predetermined conditions indicative of a level of fouling having exceeded a predetermined threshold, for example according to the second aspect of the presently disclosed subject matter.

[0163] Optionally, the controller 290 can be operatively connected to the conventional ball cleaning system 900, and can be configured to activate operation of the conventional ball cleaning system 900 concurrently with activating operation of the ball cleaning system 100, or according to a different schedule.

[0164] Referring to Fig. 11, the geometrical form of the cleaning system 100 can vary from application to application, to suit the geometrical constraints of the respective heat exchanger. Thus, for example, when applying the cleaning system 100 to the double pass heat exchanger of Fig. 7, the cleaning system 100 of Fig. 11 can configure the inlet line 200 and the outlet 300 geometrically different from the example of Fig. 1.

[0165] In the third example, and referring to Fig. 12 and Fig. 13, the shell and tube heat exchanger, generally designated with reference numeral 600', is a single pass series heat exchanger, and comprises a two heat exchanger housings 650 A, 650B coupled in series.

[0166] The two heat exchanger housings 650 A and 650B (each also referred to interchangeably herein as a shell) are similar to one another, and each is similar to the heat exchanger housing 650 of the first example as disclosed herein, mutatis mutandis.

[0167] Thus, the first heat exchanger housing 650A defines a respective heat exchange chamber 655A comprising a nominally cylindrical central portion 656A and two longitudinal ends 654A, 658A, and accommodating a respective first tube bundle of first tubes 660A (each having a respective open first tube inlet 662A, a respective open first tube outlet 664A, and a respective first lumen 665A), and a respective second tube bundle of second tubes 680A (each having a respective second tube inlet 682A, a respective open second tube outlet 684A, and a respective second lumen 685A), a respective first sheet 672A (having a respective outward facing first face 671 A, and a respective inward facing first face 673A), a respective second sheet 674A (having a respective outward facing second face 676A, and a respective inward facing second face 677 A), a respective first zone ZN1A, a respective second zone ZN2A, a respective third zone ZN3A, a respective tube-side flow path TSA, a respective shell-side flow path SSA, a respective tube side inlet 612A and a respective tube side outlet 614A, respectively similar to the first heat exchanger housing 650, heat exchange chamber 655, cylindrical central portion 656, two longitudinal ends 654, 658, first tube bundle of first tubes 660, open first tube inlets 662, open first tube outlets 664, first lumens 665, second tube bundle of second tubes 680, second tube inlets 682, open second tube outlets 684, second lumens 685, first sheet 672, outward facing first face 671, inward facing first face 673, second sheet 674, outward facing second face 676, inward facing second face 677, first zone ZN1, second zone ZN2, third zone ZN3, tube-side flow path TS, shell-side flow path SS, tube side inlet 612 and tube side outlet 614, as disclosed herein for the first example, mutatis mutandis.

[0168] Similarly, the second heat exchanger housing 650B defines a respective heat exchange chamber 655B comprising a nominally cylindrical central portion 656B and two longitudinal ends 654B, 658B, and accommodating a respective first tube bundle of first tubes 660B (each having a respective open first tube inlet 662B, a respective open first tube outlet 664B, and a respective first lumen 665B), and a respective second tube bundle of second tubes 680B (each having a respective second tube inlet 682B, a respective open second tube outlet 684B, and a respective second lumen 685B), a respective first sheet 672B (having a respective outward facing first face 671B, and a respective inward facing first face 673B), a respective second sheet 674B (having a respective outward facing second face 676B, and a respective inward facing second face 677B), a respective first zone ZN1B, a respective second zone ZN2B, a respective third zone ZN3B, a respective tube-side flow path TSB, a respective shell-side flow path SSB, a respective tube side inlet 612B and a respective tube side outlet 614B, respectively similar to the first heat exchanger housing 650, heat exchange chamber 655, cylindrical central portion 656, two longitudinal ends 654, 658, first tube bundle of first tubes 660, open first tube inlets 662, open first tube outlets 664, first lumens 665, second tube bundle of second tubes 680, second tube inlets 682, open second tube outlets 684, second lumens 685, first sheet 672, outward facing first face 671, inward facing first face 673, second sheet 674, outward facing second face 676, inward facing second face 677, first zone ZN1, second zone ZN2, third zone ZN3, tube-side flow path TS, shell-side flow path SS, tube side inlet 612 and tube side outlet 614, as disclosed herein for the first example, mutatis mutandis.

[0169] Thus, in at least this example, essentially:

[0170] - the first tubes of the first bundle of first tubes each comprises a first tube first part (corresponding to the first tubes 660A of the first heat exchanger housing 650A) accommodated in the first heat exchanger housing 650A and a first tube second part (corresponding to the first tubes 660B of the second heat exchanger housing 650A) accommodated in the second heat exchanger housing 650B; the second tubes of the second bundle of second tubes each comprises a second tube first part (corresponding to the second tubes 680A of the first heat exchanger housing 650A) accommodated in the first heat exchanger housing 650A and a second tube second part (corresponding to the second tubes 680B of the second heat exchanger housing 650A) accommodated in the second heat exchanger housing 650B; - the first heat exchanger housing comprising a respective first sheet (corresponding to first sheet 672A of the first heat exchanger housing 650A) joined to the inlet openings of the first tube first parts (i.e., first tubes 660A) of the first bundle of first tubes and to the inlet openings of the second tube first parts (i.e. second tube 680A) of the second bundle of first tubes;

[0171] - the second heat exchanger housing comprising a respective second sheet (corresponding to second sheet 674B of the second heat exchanger housing 650B) joined to the outlet openings of the first tube second parts (i.e., second tunes 660B) of the first bundle of first tubes and to the outlet openings of the second tube second parts (i.e. second tube 680B) of the second bundle of first tubes;

[0172] - the first heat exchanger housing 650 A comprising a respective second sheet (i.e., second sheet 674A) joined to the outlet openings of the first tube first parts (i.e., first tubes 660A) of the first bundle of first tubes and to the outlet openings of the second tube first parts (i.e., second tubes 680A) of the second bundle of first tubes;

[0173] - the second heat exchanger housing 650B comprising a respective first sheet (i.e., first sheet 672B) joined to the inlet openings of the first tube second parts (i.e., the first tubes 660A) of the first bundle of first tubes and to the inlet openings of the second tube second parts (i.e., the second tubes 680B) of the second bundle of first tubes.

[0174] In the third example, the tube side inlet 612A of the first heat exchanger housing 650A is the tube side inlet of the heat exchanger 600', while the tube side outlet 614B of the second heat exchanger housing 650B is the tube side outlet of the heat exchanger 600' . Furthermore, the tube side outlet 614A of the first heat exchanger housing 650A is directly connected to, and is in free fluid communication with, the tube side inlet 612B of the second heat exchanger housing 650B.

[0175] Also in the third example, the second zone ZN2A of the first heat exchanger housing 650A is contiguous with and in free fluid communication with the first zone ZN1B of the second heat exchanger housing 650B. The second zone ZN2A and the first zone ZN1B together define a collective zone ZN1B2A. In at least this example, the heat exchanger 600' optionally comprises a conventional ball cleaning system 900', for example similar to the conventional ball cleaning system 900 of the first example, mutatis mutandis, installed for enabling cleaning of the first bundle of first tubes 660A and the first bundle of tubes 660B via a plurality of first cleaning balls CB1. For example, conventional ball cleaning system 900' can be an Automatic Condenser Cleaning System (ACCS) provided by CET Enviro.

[0176] Referring to Fig. 14, a second example of cleaning system 100' comprises an inlet flow path 200', an outlet flow path 300' and a pumping system 500', substantially similar to the inlet flow path 200, outlet flow path 300 and pumping system 500 as disclosed herein for the first example of the cleaning system, mutatis mutandis, with some differences, as will become clear herein.

[0177] In particular, the second example of cleaning system 100', comprises a coupling flow path 400' for coupling between the inlet flow path 200' and the outlet flow path 300'.

[0178] As with the first example, mutatis mutandis, the inlet flow path 200' of the cleaning system 100' according to the second example is configured for selectively enabling introduction of a plurality of second cleaning balls CB2 (as disclosed herein regarding the first example, mutatis mutandis) into the first heat exchanger housing 650A of the heat exchanger 600'. The outlet flow path 300' of the cleaning system 100' according to the second example is configured for selectively enabling exit of the plurality of second cleaning balls CB2 from the second heat exchanger housing 650B of heat exchanger 600'.

[0179] The coupling flow path 400' of the cleaning system 100' according to the second example is configured for selectively enabling exit of the plurality of second cleaning balls CB2 from the first heat exchanger housing 650A and subsequent introduction of the plurality of second cleaning balls CB2 into the second heat exchanger housing 650B of heat exchanger 600'.

[0180] As with the first example, mutatis mutandis, the second cleaning balls CB2 have a nominal diameter DB2, which is nominally complementary to the inside diameter DI of the second tubes 680A, 680B, such that as the second cleaning balls CB2 are caused to flow in the second tubes 680A, 680B in operation of the cleaning system 100', the second cleaning balls CB2 clean the inside of the second tubes 680A, 680B. In particular, the inlet flow path 200' of the cleaning system 100' is configured for selectively enabling introduction of a plurality of second cleaning balls CB2 exclusively into a portion of the tube-side flow path TS corresponding to the second tubes 680A of the first heat exchanger housing 650A, while concurrently preventing introduction of the second sealing balls CB2 into another portion of the tube-side flow path TS corresponding to the first tubes 660A of the first heat exchanger housing 650A.

[0181] The inlet flow path 200' includes an inlet interface 220', an inlet line 240', a selectively actuable first valve 230', and a ball collector 260', which are similar to the inlet interface 220, inlet line 240, selectively actuable first valve 230, and ball collector 260, respectively, as disclosed herein for the first example, mutatis mutandis.

[0182] Thus, the inlet interface 220' is configured for engaging with all of the second tube inlet ends 682A of the respective second tubes 680A of first heat exchanger housing 650A, and the inlet line 240' extends between, and provides fluid communication between, the inlet interface 220' and the pumping system 500'.

[0183] The first valve 230' is provided in the inlet line 240', and in at least this example is electrically actuable between an open position, in which fluid flow (including the flow of said second cleaning balls CB2) through the inlet line 240' and the coupling flow path 400' is permitted, and a closed position, in which fluid flow (including the flow of said second cleaning balls CB2) through the inlet line 240 and the coupling flow path 400' is blocked.

[0184] The first valve 230' is operatively coupled to a controller 290' (similar to the controller 290 as disclosed herein for the first example, mutatis mutandis), that controls operation of the first valve 230' and of the pumping system 500'.

[0185] The inlet interface 220' is configured for: providing free fluid communication between the inlet flow path 200' and all of the second cluster of second tubes 680A of first heat exchanger housing 650A, in particular the respective second tube inlet ends 682A thereof; providing free fluid communication between the first zone ZN1A outside of the inlet flow path 200' and the second cluster of second tubes 680A of the first heat exchanger housing 650A; and preventing passage of the second cleaning balls CB2 between an inside of the first interface 220' and the outside of the inlet flow path 200' within the first zone ZN1A of the first heat exchanger housing 650A.

[0186] In at least this example, the inlet interface 220' is similar in form and function to the inlet interface 220 as disclosed herein for the first example, mutatis mutandis.

[0187] For example, the inlet interface 220' is in the form of a box or other convex structure, having an open end 221', outer walls 222' (having a plurality of through holes 229'), and inlet port 223' that connects the inlet interface 220' to the inlet line 240', similar to the first example, mutatis mutandis, and the open end 221' has a first peripheral lip 224' configured for abutting against, and being affixed to, the outward facing first face 671A of the first sheet 672A of the first heat exchanger housing 650A. For example, the peripheral lip 224' can optionally include a flange that is boltable or otherwise fixable with respect to the first sheet 672A on the outward facing first face 671 A.

[0188] The first peripheral lip 224' circumscribes a first area Al' on the outward facing first face 671 A, such as to enclose the second tube inlet ends 682A of all the second tubes 680A of the first heat exchanger housing 650A, and to concurrently exclude the first tube inlet ends 662A of the first tubes 660A of the first heat exchanger housing 650A, similar to the first area Al of the first example, mutatis mutandis.

[0189] The through-holes 229' provide free fluid communication between an outside of the outer walls 222' and the first internal volume thereof, and have a respective first dimension DO that is smaller than the nominal diameter DB2 of each of the second cleaning balls CB2.

[0190] The plurality of through-holes 229' provide an aggregate open area for the inlet interface 220' through which fluid can flow. This aggregate open area can be larger than the remaining solid wall of the inlet interface 220' through which fluid cannot flow, or can be equal thereto or less than the remaining solid wall of the inlet interface 220'. Thus, the number of through-holes 229' in the inlet interface 220' can be chosen to enable a desired flow to pass through the inlet interface 220' during cleaning operation. Thus, the second cleaning balls CB2 cannot pass through the outer walls 222' per se. Concurrently, the first cleaning balls CB1, which have a nominal diameter DB1 greater than the first dimension DO, also cannot pass through the outer walls 222'.

[0191] In particular, the outlet flow path 300' of the cleaning system 100 is configured for selectively enabling removal of the plurality of second cleaning balls CB2 exclusively from a portion of the tube-side flow path TS corresponding to the second tubes 680B of the second heat exchanger housing 650B, while concurrently preventing introduction of the second sealing balls CB2 into another portion of the tube-side flow path TS corresponding to the first tubes 660A of the second heat exchanger housing 650B.

[0192] The outlet flow path 300' includes an outlet interface 320', an outlet line 340', and a selectively actuable valve 330', which are similar to the outlet interface 320, outlet line 340, and selectively actuable valve 330, respectively, as disclosed herein for the first example, mutatis mutandis.

[0193] The outlet interface 320' is configured for engaging with all of the second tube outlet ends 684B of the respective second tubes 680B of the second heat exchanger housing 650B, and the outlet line 340' extends between, and provides fluid communication between, the outlet interface 320' and the pumping system 500', via the ball collector 260'.

[0194] The second valve 330' is provided in the outlet line 340', and in at least this example is electrically actuable between an open position, in which fluid flow (including the flow of said second cleaning balls CB2) through the outlet line 340' is permitted, and a closed position, in which fluid flow (including the flow of said second cleaning balls CB2) through the outlet line 340' is blocked.

[0195] The second valve 330' is operatively coupled to the controller 290', that controls operation of the second valve 330'.

[0196] The outlet interface 320' is configured for: providing free fluid communication between the outlet flow path 300' and all of the second cluster of second tubes 680B of the second heat exchanger housing 650B, in particular the respective second tube outlet ends 684B thereof; providing free fluid communication between the second zone ZN2B outside of the outlet flow path 300' of the second heat exchanger housing 650B and the second cluster of second tubes 680B of the second heat exchanger housing 650B; and preventing passage of the second cleaning balls CB2 between an inside of the outlet interface 320' and the outside of the outlet flow path 300' within the second zone ZN2B of the second heat exchanger housing 650B.

[0197] In at least this example, the outlet interface 320' is similar to the inlet interface 220', mutatis mutandis, and similarly is in the form of a box or other convex structure, having an open end 321', outer walls 322' (having a plurality of through-holes 329'), and outlet port 323' that connects the outlet interface 320' to the outlet line 340', similar to the first example, mutatis mutandis, and the open end 321' has a second peripheral lip 324' configured for abutting against, and being affixed to, the outward facing first face 676B of the second sheet 674B of the second heat exchanger housing 650B. For example, the second peripheral lip 324' can optionally include a flange that is boltable or otherwise fixable with respect to the second sheet 674B on the outward facing first face 676B of the second heat exchanger housing 650B.

[0198] The second peripheral lip 324' circumscribes a second area A2' on the outward facing first face 676B of the second heat exchanger housing 650B, such as to enclose the second tube outlet ends 684B of all the second tubes 680B of the second heat exchanger housing 650B, and to concurrently exclude the first tube outlet ends 664B of the first tubes 660B of the second heat exchanger housing 650B, similar to the second area A2 of the first example, mutatis mutandis.

[0199] The through-holes 329' provide free fluid communication between an outside of the outer walls 322' and the first internal volume thereof, and each through-hole 329' has a characteristic second dimension DOO that is smaller than the nominal diameter DB2 of each of the second cleaning balls CB2.

[0200] The plurality of through-holes 329' provide an aggregate open area for the outlet interface 320' through which fluid can flow. This aggregate open area can be larger than the remaining solid wall of the outlet interface 320' through which fluid cannot flow, or can be equal thereto or less than the remaining solid wall of the outlet interface 320'. Thus, the number of through-holes 329' in the outlet interface 320' can be chosen to enable a desired flow to pass through the outlet interface 320' during cleaning operation.

[0201] In at least this example, the first dimension DO and the second dimension DOO are nominally equal to one another.

[0202] Thus, once the second cleaning balls CB2 cannot pass through the outer walls 322' per se. Concurrently, the first cleaning balls CB1, which have a nominal diameter DB1 greater than the second dimension DOO, also cannot pass through the outer walls 322' per se.

[0203] The coupling flow path 400' of the cleaning system 100' is configured for selectively enabling passage of a plurality of second cleaning balls CB2 exclusively along a portion of the tube-side flow path TS between the second tubes 680A of the first heat exchanger housing 650A and the second tubes 680B of the second heat exchanger housing 650B, while concurrently preventing introduction of the second sealing balls CB2 into another portion of the tube-side flow path TS corresponding to the first tubes 660B of the second heat exchanger housing 650B, or indeed to the first tubes 660A of the first heat exchanger housing 650A.

[0204] The coupling flow path 400' of the cleaning system 100' essentially couples all of the second tube outlet ends 684A of the respective second tubes 680A of first heat exchanger housing 650A with all of the second tube inlet ends 682B of the respective second tubes 680B of second heat exchanger housing 650B.

[0205] The coupling flow path 400' includes an outlet interface 420', a coupling line 440', and an inlet interface 460'.

[0206] The outlet interface 420' is configured for engaging with all of the second tube outlet ends 684A of the respective second tubes 680A of first heat exchanger housing 650A

[0207] The inlet interface 460' is configured for engaging with all of the second tube inlet ends 682B of the respective second tubes 680B of second heat exchanger housing 650B.

[0208] The coupling line 440' extends between, and provides fluid communication between, the outlet interface 420' and inlet interface 460'. In at least this example, and referring again to Fig. 12, the coupling line 440' exits the tube side outlet 614A, runs outside the heat exchanger 600', and enters the tube side inlet 612B. However, in at least some alternative variations of this example, the respective coupling line can be fully accommodated within the respective heat exchanger, between the respective tube side outlet of the respective first heat exchanger housing, and the respective tube side inlet of the respective second heat exchanger housing.

[0209] The outlet interface 420' is configured for: providing free fluid communication between the coupling flow path 400' and all of the second cluster of second tubes 680A of first heat exchanger housing 650A, in particular the respective second tube outlet ends 684A thereof; providing free fluid communication between the collective zone ZN1A2B outside of the coupling flow path 400' and the second cluster of second tubes 680A of the first heat exchanger housing 650A; and preventing passage of the second cleaning balls CB2 between an inside of the outlet interface 420' and the outside of the coupling flow path 400' within the collective zone ZN1B2A.

[0210] In at least this example, the outlet interface 420' is similar in form and function to the outlet interface 320' as disclosed herein, mutatis mutandis.

[0211] For example, the outlet interface 420' is in the form of a box or other convex structure, having an open end 421', outer walls 422' (having a plurality of through holes 429'), and inlet port 423' that connects the outlet interface 420' to the coupling line 440', similar to the open end 321', outer walls 322', through holes 329', and inlet port 323', mutatis mutandis. The open end 421' has a first peripheral lip 424' configured for abutting against, and being affixed to, the outward facing second face 676A of the second sheet 674A of the first heat exchanger housing 650A. For example, the peripheral lip 424' can optionally include a flange that is boltable or otherwise fixable with respect to the second sheet 674A on the outward facing second face 676A.

[0212] The first peripheral lip 424' circumscribes a first area A3' on the outward facing second face 676A, such as to enclose the second tube outlet ends 684A of all the second tubes 680A of the first heat exchanger housing 650A, and to concurrently exclude the first tube outlet ends 664A of the first tubes 660A of the first heat exchanger housing 650A, similar to the first area A2 of the first example, mutatis mutandis.

[0213] The through-holes 429' provide free fluid communication between an outside of the outer walls 422' and the first internal volume thereof, and have a respective third dimension DO' that is smaller than the nominal diameter DB2 of each of the second cleaning balls CB2.

[0214] The plurality of through-holes 429' provide an aggregate open area for the outlet interface 420' through which fluid can flow. This aggregate open area can be larger than the remaining solid wall of the outlet interface 420' through which fluid cannot flow, or can be equal thereto or less than the remaining solid wall of the outlet interface 420'. Thus, the number of through-holes 429' in the outlet interface 420' can be chosen to enable a desired flow to pass through the outlet interface 420' during cleaning operation. In at least this example, This aggregate open area is significantly smaller than the remaining solid wall of the outlet interface 420', such that only a relatively small fluid flow can pass through the walls of the outlet interface 420', while most of the fluid flow (and second balls CB2) that arrives at the outlet interface 420' from all the second tubes 680A of the first heat exchanger housing 650A proceeds to the coupling line 440' via the inlet port 423'. In at least some alternative variations of this example, the outlet interface 420' has no through holes or other openings that would otherwise allow fluid flow through outer walls 422'.

[0215] Thus, the second cleaning balls CB2 cannot pass through the outer walls 422' per se. Concurrently, the first cleaning balls CB1, which have a nominal diameter DB1 greater than the third dimension DO', also cannot pass through the outer walls 422'.

[0216] The inlet interface 460' is configured for: providing free fluid communication between the coupling flow path 400' and all of the second cluster of second tubes 680B of second heat exchanger housing 650B, in particular the respective second tube inlet ends 682B thereof; providing free fluid communication between the collective zone ZN1B2A outside of the coupling flow path 400' and the second cluster of second tubes 680B of the second heat exchanger housing 650B; and preventing passage of the second cleaning balls CB2 between an inside of the inlet interface 460' and the outside of the coupling flow path 400' within the collective zone ZN1A2B.

[0217] In at least this example, the inlet interface 460' is similar in form and function to the inlet interface 220' as disclosed herein, mutatis mutandis.

[0218] For example, the inlet interface 460' is in the form of a box or other convex structure, having an open end 431', outer walls 432' (having a plurality of through holes 439'), and inlet port 433' that connects the inlet interface 460' to the coupling line 440', similar to the open end 321', outer walls 322', through holes 329', and inlet port 323', mutatis mutandis. The open end 431' has a first peripheral lip 434' configured for abutting against, and being affixed to, the outward facing first face 671B of the first sheet 672B of the second heat exchanger housing 650B. For example, the peripheral lip 434' can optionally include a flange that is boltable or otherwise fixable with respect to the first sheet 672B on the outward facing first face 671B.

[0219] The first peripheral lip 424' circumscribes a fourth area A4' on the outward facing first face 671B, such as to enclose the second tube inlet ends 682B of all the second tubes 680B of the second heat exchanger housing 650B, and to concurrently exclude the first tube inlet ends 662B of the first tubes 660B of the second heat exchanger housing 650B, similar to the first area Al of the first example, mutatis mutandis.

[0220] The through-holes 439' provide free fluid communication between an outside of the outer walls 432' and the first internal volume thereof, and have a respective fourth dimension DOO' that is smaller than the nominal diameter DB2 of each of the second cleaning balls CB2.

[0221] The plurality of through-holes 439' provide an aggregate open area for the inlet interface 460' through which fluid can flow. This aggregate open area can be larger than the remaining solid wall of the inlet interface 460' through which fluid cannot flow, or can be equal thereto or less than the remaining solid wall of the inlet interface 460'. Thus, the number of through-holes 439' in the inlet interface 460' can be chosen to enable a desired flow to pass through the inlet interface 460' during cleaning operation. In at least this example, This aggregate open area is significantly smaller than the remaining solid wall of the inlet interface 460', such that only a relatively small fluid flow can pass through the walls of the inlet interface 460', while most of the fluid flow (and second balls CB2) that arrives at the inlet interface 460' from coupling line 440' via the inlet port 433' proceeds to all the second tubes 680B of the second heat exchanger housing 650B. In at least some alternative variations of this example, the all the second tubes 680A of the first heat exchanger housing 650A has no through holes or other openings that would otherwise allow fluid flow through outer walls 432'. Thus, the second cleaning balls CB2 cannot pass through the outer walls 432' per se. Concurrently, the first cleaning balls CB1, which have a nominal diameter DB1 greater than the fourth dimension DOO', also cannot pass through the outer walls 432'.

[0222] In at least this example, the third dimension DO' and the fourth dimension DOO' are nominally equal to one another.

[0223] In at least this example, the first dimension DO, the second dimension DOO, the third dimension DO' and the fourth dimension DOO', are all nominally equal to one another.

[0224] The ball collector 260' is provided in the inlet line 240', between the inlet interface 220' and the pumping system 500', and in at least this example between the first valve 230' and the pumping system 500'.

[0225] The ball collector 260' is also concurrently provided in the outlet line 340', between the outlet interface 320' and the pumping system 500', and in at least this example between the second valve 330' and the pumping system 500'.

[0226] Thus the inlet line 240' and the outlet line 340' are in selective fluid communication with one another via the ball collector 260' and pumping system 500'.

[0227] The ball collector 260' operates as a reservoir for the second cleaning balls CB2, and thus has a volumetric capacity to accommodate the plurality of second cleaning balls CB2.

[0228] The ball collector 260' is thus in fluid communication with the pumping system 500' and the inlet interface 220' via the inlet line 240' and first valve 230'. Under the action of the pumping system 500' (and when the first valve 230' is open, and the second valve 330' is closed), for example under positive pressure generated by the pumping system 500', enables the plurality of second cleaning balls CB2 to be delivered to the inlet interface 220'.

[0229] Similarly, the ball collector 260' is also in fluid communication with the pumping system 500' and the outlet interface 320' via the outlet line 340' and second valve 330'. Under the action of the pumping system 500' (and when the second valve 330' is open, and the first valve 230' is closed), for example under negative (suction) pressure generated by the pumping system 500', enables the plurality of second cleaning balls CB2 to be received from the outlet interface 320.

[0230] The ball collector 260' is in fluid communication with the pumping system 500', selectively allowing working fluid to be pumped from the pumping system 500' and through the ball collector 260' in first direction towards the inlet interface 220, and selectively allowing working fluid to be pumped to the pumping system 500 through the ball collector 260' in a second direction (opposite to the first direction) from the outlet interface 320'. The ball collector 260' also includes a net, trap, or other filtering arrangement at a longitudinal end thereof closest to the pumping system 500, to prevent the second cleaning balls CB2 from passing from the ball collector 260' to the pumping system 500'.

[0231] The pumping system 500' includes any suitable pump that can be operated to provide a desired fluid flow in both directions through the pumping system 500' - in a first direction from the pumping system 500' towards the inlet interface 220' in the inlet flow path 200', and in a second direction (opposite to the first direction) towards the pumping system 500' from the outlet interface 320' in the outlet flow path 300'.

[0232] The cleaning system 100' can be coupled to the heat exchanger 600' by engaging or otherwise affixing the inlet interface 220' to the outward facing first face 671A of the first sheet 672A of the first heat exchanger housing 650A via the open end 221', and such that the first peripheral lip 224' circumscribes the first area Al' on the outward facing first face 671A. In other words, the inlet interface 220' is affixed to the first sheet 672A of the in a manner to enclose therein the second tube inlet ends 682A of all the second tubes 680A of the first heat exchanger housing 650A, and to concurrently exclude the first tube inlet ends 662A of all the first tubes 660A of the first heat exchanger housing 650A Similarly, coupling of the cleaning system 100' to the heat exchanger 600' is further accomplished by engaging or otherwise affixing the outlet interface 320' to the outward facing second face 676B of the second sheet 674B of the second heat exchanger housing 650B via the open end 321', and such that the second peripheral lip 324' circumscribes the second area A2' on the outward facing first face 676B. In other words, the outlet interface 320' is affixed to the second sheet 674B of the second heat exchanger housing 650B in a manner to enclose therein the second tube outlet ends 684B of all the second tubes 680B and to concurrently exclude the first tube second ends 664B of the first tubes 660B of the second heat exchanger housing 650B.

[0233] Furthermore, coupling of the cleaning system 100' to the heat exchanger 600' is further accomplished by engaging or otherwise affixing the outlet interface 420' to the outward facing second face 676 A of the second sheet 674 A of the first heat exchanger housing 650A via the open end 421', and such that the second peripheral lip 424' circumscribes the third area A3' on the outward facing second face 676B. In other words, the outlet interface 420' is affixed to the second sheet 674A of the first heat exchanger housing 650A in a manner to enclose therein the second tube outlet ends 684A of all the second tubes 680A and to concurrently exclude the first tube second ends 664A of the first tubes 660A of the first heat exchanger housing 650A.

[0234] Similarly, coupling of the cleaning system 100' to the heat exchanger 600' is further accomplished by engaging or otherwise affixing the inlet interface 460' to the outward facing first face 671B of the first sheet 672B of the second heat exchanger housing 650B via the open end 431', and such that the second peripheral lip 434' circumscribes the fourth area A4' on the outward facing first face 671A. In other words, the inlet interface 460' is affixed to the first sheet 674B of the second heat exchanger housing 650B in a manner to enclose therein the second tube inlet ends 682B of all the second tubes 680B and to concurrently exclude the first tube inlet ends 662B of the first tubes 660B of the second heat exchanger housing 650B.

[0235] Thus, when required or desired to operate the cleaning system 100' to clean the second tubes 680A, 680B of the heat exchanger 600', the controller 290' operates to close the second valve 330' and to concurrently open the first valve 230'. At this point the second cleaning balls CB2 are accommodated in the ball collector 260'. The controller 290' then operates the pumping system 500' to cause a fluid flow to flow in the first direction through the inlet flow path 200' and towards the inlet interface 220', carrying the second cleaning balls CB2 with the fluid flow. Thereafter, continued pumping action by the pumping system 500' urges the second cleaning balls CB2 to flow through the second tubes 680A of the first heat exchanger housing 650A, thereby cleaning the inside surfaces of the second tubes 680A, and the second cleaning balls CB2 essentially pass through to the outlet interface 420'.

[0236] As the pumping system 500' continues to operate, the second cleaning balls CB2 are urged to flow in the coupling flow path 400', from outlet interface 420', through the coupling line 440', and to the inlet interface 460'.

[0237] As the pumping system 500' continues to operate further, the second cleaning balls CB2 are urged to flow through the second tubes 680B of the second heat exchanger housing 650B, thereby cleaning the inside surfaces of the second tubes 680B, and the second cleaning balls CB2 essentially pass through to the outlet interface 320'.

[0238] When all the cleaning balls CB2 are accumulated at the outlet interface 320', for example after a predetermined period of time in which the pumping system 500' is operating in the first direction, the controller 290' operates to open the second valve 330' and to concurrently close the first valve 230'.

[0239] The controller 290' then operates the pumping system 500' to cause a fluid flow to flow in the second direction through the outlet flow path 300' and from the outlet interface 320', carrying the second cleaning balls CB2 with the fluid flow, towards the pumping system 500' and the ball collector 260'. Thereafter, pumping action by the pumping system 500' continues until all the second cleaning balls CB2 are collected at the ball collector 260', for example after a predetermined period of time in which the pumping system 500' is operating in the second direction.

[0240] For example, the cleaning system 100' can be configured for operating according to a fixed schedule, for example in which the cleaning system 100' operates to clean the second tubes 680A, 680B in periodic intervals, wherein such intervals can be for example, once every 30 minutes. Alternatively, for example, the cleaning system 100' can be configured for operating according to predetermined conditions indicative of a level of fouling having exceeded a predetermined threshold, for example according to the second aspect of the presently disclosed subject matter.

[0241] Optionally, the controller 290' can be operatively connected to the conventional ball cleaning system 900', and can be configured to activate operation of the conventional ball cleaning system 900' concurrently with activating operation of the ball cleaning system 100, or according to a different schedule.

[0242] According to a second aspect of the presently disclosed subject matter, there is provided a control system, and corresponding method of operation, the control system configured to monitor a level of fouling of the tube side flow path of a shell and tube heat exchanger, and further configured to activate a cleaning system with cleaning balls, responsive to the level having exceeded a predetermined threshold.

[0243] According to this aspect of the presently disclosed subject matter, such a shell and tube heat exchanger can include any shell and tube heat exchanger that includes a shell-side flow path and a tube side flow path, for example as discussed herein. For example, the shell and tube heat exchanger can be a single pass heat exchanger, for example as disclosed herein relating to Figs. 1 to 6, mutatis mutandis, or a double pass heat exchanger, for as disclosed herein relating to Figs. 7 to 11, mutatis mutandis, or a single pass series heat exchanger, for as disclosed herein relating to Figs. 12 to 14, mutatis mutandis. Such a shell and tube heat exchanger can be used in a variety of applications, for example as chiller or as a condenser.

[0244] In any case, and referring to Fig. 15, such a heat exchanger, generically referred to herein by reference numeral 1000, includes a tube side flow path TSFP and a shell side flow path SSFP.

[0245] The tube side flow path TSFP extends between a heat exchanger tube side inlet 1010, a heat exchanger tube side outlet 1020 and the lumens 1070 of a plurality of tubes 1030 therebetween.

[0246] The shell side flow path SSFP extends between a heat exchanger shell side inlet 1040, a heat exchanger shell side outlet 1050 and the external surfaces 1060 of the plurality of tubes 1030 therebetween. While in Fig. 15 the shell and tube heat exchanger is schematically depicted as a single pass heat exchanger, the following disclosure also applies, mutatis mutandis, to other types of shell and tube heat exchangers, for example double pass heat exchangers or single pass series heat exchangers.

[0247] According to this aspect of the presently disclosed subject matter, such a cleaning system can include a conventional cleaning system, installed for enabling cleaning of the bundle of tubes 1030, for example similar to the conventional ball cleaning system 900 of the above first example according to the first aspect of the presently disclosed subj ect matter, mutatis mutandis, via a plurality of first cleaning balls CB1. For example, conventional ball cleaning system 900 can be an Automatic Condenser Cleaning System (ACCS) provided by CET Enviro.

[0248] Additionally or alternatively, according to the second aspect of the presently disclosed subject matter, and in the example of Fig. 15, the tubes 1030 of the tube side flow path TSFP includes a first bundle of first tubes having a first diameter, and a second bundle of second tubes having a second diameter, for example according to the first aspect of the presently disclosed subject matter, for example as disclosed herein regarding Figs. 1 to 14, mutatis mutandis. In such examples, and referring for example to Fig. 15, two ball cleaning systems can be provided, a first ball cleaning system 1400 for cleaning the lumens of the first bundle of first tubes, and a second ball cleaning system 1600 for cleaning the second bundle of second tubes.

[0249] For example, such a first ball cleaning system 1400 can include a conventional cleaning system, installed for enabling cleaning of the first bundle of tubes of the plurality of tubes 1030, for example similar to the conventional ball cleaning system 900 of the above first example according to the first aspect of the presently disclosed subject matter, mutatis mutandis, via a plurality of first cleaning balls CB1. For example, conventional ball cleaning system 1400 can be an Automatic Condenser Cleaning System (ACCS) provided by CET Enviro.

[0250] For example, the second cleaning system 1600 can include the cleaning system 100 or 100' according to the first aspect of the presently disclosed subject matter, for example as disclosed herein regarding Figs. 1 to 6, mutatis mutandis, or for example as disclosed herein regarding Figs. 7 to 11, mutatis mutandis, or for example as disclosed herein regarding Figs. 12 to 14, mutatis mutandis.

[0251] Referring again to Fig. 15, a first example of a control system according to the second aspect of the presently disclosed subject matter, generally designated with reference numeral 2000, comprises a controller 2100 operatively coupled to a monitoring system 2300.

[0252] The controller 2100 is also operatively coupled to the first ball cleaning system 1400 and to the second ball cleaning system 1600, in a manner to cause the first ball cleaning system 1400 and to the second ball cleaning system 1600 to selectively operate to clean the tubes 1030 of the tube side flow path TSFP of the heat exchanger. In at least some alternative variations of this example, in which there is only a one ball cleaning system, for example a conventional cleaning system, the respective controller is operatively coupled to the respective ball cleaning system.

[0253] The monitoring system 2300 is configured to monitor a level of fouling of the tube side flow path TSFP of the shell and tube heat exchanger. Such a level of fouling can be determined with respect to one or more fouling parameters FP.

[0254] A first such fouling parameter, generally designated herein with reference numeral FP1, is the so-called approach temperature TA of the heat exchanger 1000.

[0255] The approach temperature TA is defined herein as the difference in temperature between a first temperature Ti at the heat exchanger tube side outlet 1020 of the tube side flow path TSFP, and a second temperature T2 at the heat exchanger shell side outlet 1050 of the shell side flow path SSFP, i.e.:

[0256] FP1 = TA = Ti - T2

[0257] Accordingly, in at least this example, monitoring system 2300 includes at least a first temperature sensor 2310 configured for monitoring the first temperature Ti at the heat exchanger tube side outlet 1020 of the tube side flow path TSFP, and a second temperature sensor 2320 configured for monitoring the second temperature T2 at heat exchanger shell side outlet 1050 of the shell side flow path SSFP. The first temperature sensor 2310 and the second temperature sensor 2320 are operatively coupled to the controller 2100, for example via lines 2312 and 2322 respectively, and are configured for providing electrical, digital or electronic signals to the controller 2100 representative of the respective first temperature Ti and second temperature T2 being monitored by the first temperature sensor 2310 and the second temperature sensor 2320.

[0258] For example, each one of the first temperature sensor 2310 and the second temperature sensor 2320 can include any suitable temperature sensor, which are well known in the art for example.

[0259] The controller 2100 is configured for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, responsive to the first fouling parameter FP1, i.e., the approach temperature TA exceeding a predetermined threshold temperature TT.

[0260] Such a threshold temperature TT can depend on the specific heat exchanger, and can vary between one heat exchanger and another heat exchanger.

[0261] The threshold temperature TT can be defined as a particular approach temperature TA at which a particular level of fouling is suspected in the lumens 1070 is affecting the efficiency of the heat exchanger on the one hand, but is still low enough to be removable by the respective cleaning balls CB1, CB2, on the other hand.

[0262] The threshold temperature TT can be determined for any particular heat exchanger for example via an approach temperature calibration process.

[0263] For example, such a calibration process can include running the heat exchanger for a predetermined length of time, for example one or two days, and automatically activating the first ball cleaning system 1400 and to the second ball cleaning system 1600 at a baseline frequency, for example once every 30 minutes. Concurrently, the approach temperature TA is monitored. This can be repeated a few times, each time changing the cleaning frequency, for example to once an hour, once every ninety minutes and so on. The variation of approach temperature TA with cleaning frequency can then be determined. For example, when the heat exchanger is first used, the respective approach temperature TA provides a baseline approach temperature TAO that corresponds to relatively clean lumens 1070. Prior to each cleaning cycle the approach temperature TA is expected to increase. The slower the cleaning frequency, i.e., the longer the time interval between cleaning cycles, the higher the approach temperature TA is expected to be prior to the cleaning cycle being started. If after each cleaning cycle, at a particular cleaning frequency, the approach temperature TA returns to the baseline approach temperature TAO (or within a particular percentage thereof, for example 20% thereof, then it can be assumed that the cleaning cycle, at the cleaning frequency, is successful and effective. On the other hand, if the approach temperature TA does not return to the baseline approach temperature TAO after cleaning cycles at a particular cleaning frequency, this can be indicative that there is too much fouling, and the respective approach temperature TA prior to the cleaning cycle is above such a desired threshold temperature TT.

[0264] From the above calibration process, an assessment of a reasonable or maximum approach temperature TA can be provided (corresponding to the respective threshold temperature TT) in which it can be expected that the approach temperature TA will return to the baseline approach temperature TAO, or within some range close thereto, after the cleaning cycle.

[0265] For example, the threshold temperature TT can be 0.3°C or 0.5°C, or within a range 0.3°C to 1.0°C, or within a range 0.5°C to 1.5°C, or within a range 0.5°C to 2.0°C, or within a range 0.5°C to 3.0°C.

[0266] Optionally, the rate at which the approach temperature TA is increasing can be monitored, and the controller 2100 can be configured for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, responsive to the rate of change of the approach temperature TA exceeding a predetermined threshold rate. Such a predetermined rate can be determined via a calibration process, for example similar to the above calibration process for the threshold temperature, mutatis mutandis.

[0267] Optionally, suitable algorithms based on Al (artificial intelligence) can be generated for optimizing operation of the controller 2100 for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, based on the approach temperature TA and / or the rate of change of the approach temperature TA.

[0268] The use of the first parameter FP1 can be particular advantageous in at least some applications in which the respective heat exchanger is in the form of a water-cooled condenser or in the form of a chiller, in which the first temperature Ti corresponds to the respective saturated refrigerant condensing temperature, and the second temperature T2 corresponds to the respective leaving condenser water temperature. In at least some examples, a second such fouling parameter, generally designated herein with reference numeral FP2, is the vacuum or negative pressure generated at the at the heat exchanger shell side inlet 1040 of the shell side flow path SSFP of the heat exchanger 1000.

[0269] The second fouling parameter FP2 can be particular advantageous in at least some applications in which the respective heat exchanger is in the form of a condenser in power stations and the like, in which the shell side fluid that flows into shell side flow path SSFP is in the form of steam entering the heat exchanger shell side inlet 1040, the steam condensing into liquid water prior to exiting the heat exchanger shell side outlet 1050.

[0270] Without being bound to theory, inventor considers that as the level of fouling in the lumens 1070 increases, the efficiency of the heat exchanger reduces, and thus the shell side flow path SSFP is less effective in producing the necessary heat transfer, leading to lower levels of condensation in the shell side flow path SSFP, which in turn changes the level of the negative pressure at the heat exchanger shell side inlet 1040.

[0271] Accordingly, in at least this example, monitoring system 2300 includes at least a pressure sensor 2340 configured for monitoring the pressure Pi at the heat exchanger shell side inlet 1040. The pressure sensor 2340 is operatively coupled to the controller 2100, for example via line 2342, and are configured for providing electrical, digital or electronic signals to the controller 2100 representative of the pressure Pi being monitored by the pressure sensor 2340.

[0272] For example, pressure sensor 2340 can include any suitable pressure sensor, which are well known in the art for example.

[0273] The controller 2100 is configured for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, responsive to the second fouling parameter FP2, i.e., the pressure Pi exceeding a predetermined threshold pressure PT.

[0274] Such a threshold pressure PT can depend on the specific heat exchanger, and can vary between one heat exchanger and another heat exchanger.

[0275] The threshold pressure PT can be defined as a particular pressure Pi at which a particular level of fouling is suspected in the lumens 1070 is affecting the efficiency of the heat exchanger on the one hand, but is still low enough to be removable by the respective cleaning balls CB1, CB2, on the other hand.

[0276] The threshold pressure PT can be determined for any particular heat exchanger for example via a pressure calibration process, for example similar to the temperature calibration process as disclosed herein, mutatis mutandis.

[0277] Optionally, the rate at which the pressure Pi is changing can be monitored, and the controller 2100 can be configured for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, responsive to the rate of change of the pressure Pi exceeding a predetermined threshold rate. Such a predetermined rate can be determined via a calibration process, for example similar to the above calibration process for the threshold temperature, mutatis mutandis.

[0278] Optionally, suitable algorithms based on Al (artificial intelligence) can be generated for optimizing operation of the controller 2100 for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, based on the pressure Pi and / or the rate of change of the pressure Pi.

[0279] In at least some examples, a third such fouling parameter, generally designated herein with reference numeral FP3, is the pressure difference AP in the tube side flow path TSFP, between the heat exchanger tube side inlet 1010 and the heat exchanger tube side outlet 1020 of the heat exchanger 1000.

[0280] The third fouling parameter FP3 can be particular advantageous in at least some applications of shell and tube heat exchangers.

[0281] Without being bound to theory, inventor considers that as the level of fouling in the lumens 1070 increases, the pressure difference AP drops.

[0282] Accordingly, in at least this example, monitoring system 2300 includes at least a first pressure sensor 2350 configured for monitoring a first pressure Pi at the heat exchanger tube side inlet 1010, and a second pressure sensor 2360, configured for monitoring a second pressure P2 at the heat exchanger tube side outlet 1020. The first pressure sensor 2350 and the second pressure sensor 2360 are each operatively coupled to the controller 2100, for example via lines 2352, 2362, and are configured for providing electrical, digital or electronic signals to the controller 2100 representative of the first pressure Pi being monitored by the first pressure sensor 2350, and the second pressure P2 being monitored by the second pressure sensor 2360.

[0283] For example, first pressure sensor 2350 and the second pressure sensor 2360 can each include any suitable pressure sensor, which are well known in the art for example.

[0284] The pressure difference AP is defined herein as the difference in pressure between the first pressure Pi and the second pressure P2, i.e.:

[0285] FP3 = AP = Pi - P2

[0286] The controller 2100 is configured for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, responsive to the third fouling parameter FP3, i.e., the pressure difference AP exceeding a predetermined threshold pressure difference APT.

[0287] Such a threshold pressure difference APT can depend on the specific heat exchanger, and can vary between one heat exchanger and another heat exchanger.

[0288] The threshold pressure difference APT can be defined as a particular pressure difference AP at which a particular level of fouling is suspected in the lumens 1070 is affecting the efficiency of the heat exchanger on the one hand, but is still low enough to be removable by the respective cleaning balls CB1, CB2, on the other hand.

[0289] The threshold pressure difference APT can be determined for any particular heat exchanger for example via a pressure calibration process, for example similar to the temperature calibration process as disclosed herein, mutatis mutandis.

[0290] Optionally, the rate at which the pressure difference APT is changing can be monitored, and the controller 2100 can be configured for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, responsive to the rate of change of the pressure difference APT exceeding a predetermined threshold rate. Such a predetermined rate can be determined via a calibration process, for example similar to the above calibration process for the threshold temperature, mutatis mutandis. Optionally, suitable algorithms based on Al (artificial intelligence) can be generated for optimizing operation of the controller 2100 for activating the first ball cleaning system 1400 and the second ball cleaning system 1600, based on the pressure difference APT and / or the rate of change of the pressure difference APT.

[0291] In the method claims that follow, alphanumeric characters and Roman numerals used to designate claim steps are provided for convenience only and do not imply any particular order of performing the steps.

[0292] Finally, it should be noted that the word “comprising” as used throughout the appended claims is to be interpreted to mean “including but not limited to”.

[0293] While there has been shown and disclosed examples in accordance with the presently disclosed subject matter, it will be appreciated that many changes may be made therein without departing from the scope of the presently disclosed subject matter as set out in the claims.

Claims

CLAIMS:

1. A cleaning system for a shell and tube heat exchanger, the shell and tube heat exchanger including a first tube bundle of first tubes, each said first tube having a respective first tube lumen, and a second tube bundle of second tubes, each said second tube having a respective second lumen, the first lumens each having a first internal diameter, the second lumens each having a second diameter, the second diameter being different from the first diameter, the cleaning system comprising: an inlet flowpath, configured for enabling introduction of a plurality of cleaning balls into the shell and tube heat exchanger, the inlet flowpath having a first interface configured for engaging with an inlet end of said second cluster of second tubes, the first interface configured for: providing free fluid communication between the inlet flowpath and said second cluster of second tubes via an inside of the first interface; providing free fluid communication between an outside of the inlet flowpath within the heat exchange chamber and said second cluster of second tubes via the inside of the first interface; and preventing passage of the balls between the inside of the first interface and the outside of the inlet flowpath within the heat exchange chamber; an outlet flowpath configured for enabling extraction of the cleaning balls out of the shell and tube heat exchanger, the outlet flowpath having a second interface configured for engaging with an outlet end of said second cluster of second tubes, the second interface configured for: providing free fluid communication between the outlet flowpath and said second cluster of second tubes via an inside of the second interface; providing free fluid communication between an outside of the outlet flowpath within the heat exchange chamber and said second cluster of second tubes via the inside of the second interface; and preventing passage of the balls between the inside of the second interface and the outside of the outlet flowpath within the heat exchange chamber; a pumping system configured for selectively causing the cleaning balls to be introduced into the shell and tube heat exchanger via the inlet flowpath and to exit the shell and tube heat exchanger via the outlet flowpath; wherein the cleaning balls are configured for cleaning said second lumens.

2. The cleaning system according to claim 1, wherein said cleaning balls are incapable of cleaning said first lumens.

3. The cleaning system according to any one of claims 1 to 2, wherein said inlet flow path comprises an inlet line, a selectively actuable first valve, and a ball collector, wherein the inlet line extends between, and provides fluid communication between, the first interface and the pumping system.

4. The cleaning system according to any one of claims 1 to 3, wherein said first interface is configured for being affixed to a first sheet of the shell and tube heat exchanger.

5. The cleaning system according to any one of claims 1 to 4, wherein said first interface is configured for engaging with respective second tube inlet ends of the second tubes.

6. The cleaning system according to any one of claims 1 to 5, wherein said first interface comprises a first convex structure defining enclose a first internal volume of the first interface, said first convex structure having a first open end, first outer walls, and an inlet port.

7. The cleaning system according to claim 6, wherein said inlet port connects the first interface to the inlet line.

8. The cleaning system according to any one of claims 6 to 7 when depending from claim 4, wherein said first open end has a first peripheral lip configured for abutting against, and being affixed to, an outward facing first face of the first sheet.

9. The cleaning system according to claim 8, wherein the first peripheral lip is fixable with respect to the first sheet on the outward facing first face of the first sheet.

10. The cleaning system according to any one of claims 8 to 9, wherein said first peripheral lip circumscribes a first area on the outward facing first face of the first sheet, wherein said first area is such as to enclose said inlet ends of said second cluster of second tubes, and to concurrently exclude respective first tube inlet ends of the first tubes.

11. The cleaning system according to any one of claims 6 to 10, wherein said first outer walls comprise a plurality of first through-holes, wherein said first through-holes provide free fluid communication between an outside of the first outer walls and the first internal volume.

12. The cleaning system according to claim 11, wherein the first outer walls are formed from sheets of a contiguous material, and which include the plurality of said first through-holes.

13. The cleaning system according to claim 11 , wherein said first outer walls are made from a net-like material having a plurality of respective weave threads and weft threads interlinked with one another, and in which the plurality of said first through-holes are formed in respective open areas formed between the weave threads and the weft threads.

14. The cleaning system according to any one of claims 11 to 13, wherein said first through-holes each have a characteristic first dimension that is smaller than a nominal diameter of each of the cleaning balls.

15. The cleaning system according to any one of claims 1 to 14, wherein said outlet flow path comprises an outlet line, and a selectively actuable second valve, wherein the outlet line extends between, and provides fluid communication between, the second interface and the pumping system.

16. The cleaning system according to any one of claims 1 to 15, wherein said second interface is configured for being affixed to a second sheet of the shell and tube heat exchanger.

17. The cleaning system according to any one of claims 1 to 16, wherein said second interface is configured for engaging with respective second tube outlet ends of the second tubes.

18. The cleaning system according to any one of claims 1 to 17, wherein said second interface comprises a second convex structure defining enclose a second internal volume of the second interface, said second convex structure having a second open end, second outer walls, and an outlet port.

19. The cleaning system according to claim 18, wherein said outlet port connects the second interface to the outlet line.

20. The cleaning system according to any one of claims 18 to 19 when depending from claim 16, wherein said second open end has a second peripheral lip configured for abutting against, and being affixed to, an outward facing first face of the second sheet.

21. The cleaning system according to claim 20, wherein the second peripheral lip is fixable with respect to the second sheet on the outward facing first face of the second sheet.

22. The cleaning system according to any one of claims 20 to 21, wherein said second peripheral lip circumscribes a second area on the outward facing first face of the second sheet, wherein said second area is such as to enclose said outlet ends of said second cluster of second tubes, and to concurrently exclude respective second tube inlet ends of the first tubes.

23. The cleaning system according to any one of claims 18 to 22, wherein said second outer walls comprise a plurality of second through-holes, wherein said second through- holes provide free fluid communication between an outside of the second outer walls and the second internal volume.

24. The cleaning system according to claim 23, wherein the second outer walls are formed from sheets of a contiguous material, and which include the plurality of said second through-holes.

25. The cleaning system according to claim 23, wherein said second outer walls are made from a net-like material having a plurality of respective weave threads and weft threads interlinked with one another, and in which the plurality of said second through- holes are formed in respective open areas formed between the weave threads and the weft threads.

26. The cleaning system according to any one of claims 23 to 25, wherein said second through-holes each have a characteristic second dimension that is smaller than a nominal diameter of each of the cleaning balls.

27. The cleaning system according to any one of claims 3 to 26, comprising a controller operatively coupled to the first valve, the second valve, and the pumping system.

28. The cleaning system according to any one of claims 3 to 27, wherein the pumping system is configured for operating to selectively cause a first fluid flow to flow through the inlet flow path in a first direction from the pumping system to the first interface, and for enabling a plurality of said cleaning balls to flow within said first fluid flow.

29. The cleaning system according to claim 28, wherein the pumping system is further configured for operating to selectively cause a second fluid flow to flow through the outlet flow path in a second direction from the second interface to the pumping system, and for enabling the plurality of said cleaning balls to flow within said second fluid flow.

30. The cleaning system according to any one of claims 1 to 29, wherein the shell and tube heat exchanger is a single pass heat exchanger.

31. The cleaning system according to any one of claims 1 to 29, wherein the shell and tube heat exchanger is a double pass heat exchanger.

32. The cleaning system according to any one of claims 1 to 29, wherein the shell and tube heat exchanger is a single pass series heat exchanger, comprising a first heat exchanger housing and a second heat exchanger housing, coupled to one another in series, wherein:- the first tubes of the first bundle of first tubes each comprises a first tube first part accommodated in the first heat exchanger housing and a first tube second part accommodated in the second heat exchanger housing; the second tubes of the second bundle of second tubes each comprises a second tube first part accommodated in the first heat exchanger housing and a second tube second part accommodated in the second heat exchanger housing;- the first heat exchanger housing comprising a respective first sheet joined to the inlet openings of the first tube first parts of the first bundle of first tubes and to the inlet openings of the second tube first parts of the second bundle of first tubes;- the second heat exchanger housing comprising a respective second sheet joined to the outlet openings of the first tube second parts of the first bundle of first tubes and to the outlet openings of the second tube second parts of the second bundle of first tubes;- the first heat exchanger housing comprising a respective second sheet joined to the outlet openings of the first tube first parts of the first bundle of first tubes and to the outlet openings of the second tube first parts of the second bundle of first tubes;- the second heat exchanger housing comprising a respective first sheet joined to the inlet openings of the first tube second parts of the first bundle of first tubes and to the inlet openings of the second tube second parts of the second bundle of first tubes.

33. The cleaning system according to claim 32, further comprising a coupling flow path for coupling between the inlet flow path and the outlet flow path.

34. The cleaning system according to claim 33, wherein: said inlet flow path is configured for selectively enabling introduction of the cleaning balls into the first heat exchanger housing of the heat exchanger; said outlet flow path is configured for selectively enabling exit of the cleaning balls from the second heat exchanger housing of heat exchanger; and said coupling flow path is configured for selectively enabling exit of the cleaning balls from the first heat exchanger housing and subsequent introduction of the cleaning balls into the second heat exchanger housing of heat exchanger.

35. The cleaning system according to any one of claims 33 to 34, wherein the coupling flow path is configured for selectively enabling passage of the cleaning balls exclusively along a portion of a tube-side flow path between the second tubes of the first heat exchanger housing and the second tubes of the second heat exchanger housing, while concurrently preventing introduction of the sealing balls into another portion of the tubeside flow path corresponding to the first tubes of the second heat exchanger housing, or to the first tubes of the first heat exchanger housing.

36. The cleaning system according to any one of claims 33 to 35, wherein the coupling flow path couples all of the second tube outlet ends of the respective second tubes of first heat exchanger housing with all of the second tube inlet ends of the respective second tubes of second heat exchanger housing.

37. The cleaning system according to any one of claims 33 to 36, wherein the coupling flow path includes an outlet interface, a coupling line, and an inlet interface.

38. The cleaning system according to claim 37, wherein the coupling line extends between, and provides fluid communication between, the outlet interface and inlet interface.

39. The cleaning system according to any one of claims 37 and 38, wherein the outlet interface is configured for engaging with all of the second tube outlet ends of the respective second tubes of first heat exchanger housing, and wherein the inlet interface is configured for engaging with all of the second tube inlet ends of the respective second tubes of second heat exchanger housing.

40. The cleaning system according to claim 39, wherein said outlet interface is configured for being affixed onto the respective second sheet of the first heat exchanger housing, and wherein said inlet interface is configured for being affixed onto the respective first sheet of the second heat exchanger housing.

41. A heat exchanger comprising a cleaning system as defined herein in any one of claims 1 to 40.

42. A heat exchanger according to claim 41, further comprising a conventional ball cleaning system configured for cleaning the first tubes.

43. A control system configured to monitor a parameter representative of fouling of the tube side flow path of a shell and tube heat exchanger, and further configured to activate a ball cleaning system with cleaning balls, responsive to the magnitude of the parameter crossing a predetermined threshold.

44. The control system according to claim 43, comprising a control system controller operatively coupled to a monitoring system.

45. The control system according to claim 44, wherein the controller is operatively coupled to the ball cleaning system.

46. The control system according to any one of claims 44 to 45, wherein said monitoring system is configured to monitor a level of fouling of the tube side flow path of the shell and tube heat exchanger with respect to one or more fouling parameters.

47. The control system according to claim 46, wherein a first said fouling parameter is an approach temperature of the shell and tube heat exchanger, wherein the approach temperature is a difference in temperature between a first temperature at a heat exchanger tube side outlet of the tube side flow path, and a second temperature at a heat exchanger shell side outlet of a shell side flow path of the shell and tube heat exchanger.

48. The control system according to claim 47, wherein said monitoring system includes at least a first temperature sensor configured for monitoring the first temperature at the heat exchanger tube side outlet of the tube side flow path, and a second temperature sensor configured for monitoring the second temperature at heat exchanger shell side outlet of the shell side flow path, and wherein the at least one first temperature sensor and the at least one second temperature sensor are operatively coupled to the control system controller.

49. The control system according to claim 48, wherein the at least one first temperature sensor and the at least one second temperature sensor are configured for providing electrical, digital or electronic signals to the control system controller representative of the respective first temperature and second temperature being monitored by the first temperature sensor and the second temperature sensor.

50. The control system according to any one of claims 47 to 49, wherein the control system controller is configured for activating the ball cleaning system responsive to the approach temperature exceeding a predetermined threshold temperature.

51. The control system according to any one of claims 46 to 50, wherein a second said fouling parameter is a level of negative pressure generated at the at a heat exchanger shell side inlet of a shell side flow path of the shell and tube heat exchanger.

52. The control system according to claim 51 , wherein the monitoring system includes at least a pressure sensor configured for monitoring a pressure at the heat exchanger shell side inlet, wherein the pressure sensor is operatively coupled to the control system controller.

53. The control system according to claim 52, wherein the at least one pressure sensor is configured for providing electrical, digital or electronic signals to the control system controller representative of the pressure being monitored by the pressure sensor.

54. The control system according to any one of claims 52 to 53, wherein the control system controller is configured for activating the ball cleaning system, responsive to the pressure exceeding a predetermined threshold pressure.

55. The control system according to any one of claims 46 to 54, wherein a third said fouling parameter is a pressure difference in the tube side flow path, between a heat exchanger tube side inlet and a heat exchanger tube side outlet of the shell and tube heat exchanger.

56. The control system according to claim 55, wherein the monitoring system includes at least a first pressure sensor configured for monitoring a first pressure at the heat exchanger tube side inlet, and a second pressure sensor, configured for monitoring a second pressure at the heat exchanger tube side outlet, and wherein the first pressure sensor and the second pressure sensor are each operatively coupled to the control system controller.

57. The control system according to claim 56, wherein the first pressure sensor and the second pressure sensor are each configured for providing electrical, digital or electronic signals to the control system controller representative of the first pressure being monitored by the first pressure sensor, and the second pressure being monitored by the second pressure sensor.

58. The control system according to any one of claims 55 to 57, wherein said control system controller is configured for activating the ball cleaning system, responsive to the pressure difference exceeding a predetermined threshold pressure difference.

59. The control system according to any one of claims 43 to 58, wherein the ball cleaning system includes the cleaning system as defined in any one of claims 1 to 40.

60. The control system according to any one of claims 43 to 59, wherein the ball cleaning system includes a conventional ball cleaning system.

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