GB2274322A

GB2274322A - Cleaning heat exchanger tubes

Info

Publication number: GB2274322A
Application number: GB9400504A
Authority: GB
Inventors: Henry Mcgaughey
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-13
Filing date: 1994-01-12
Publication date: 1994-07-20
Also published as: GB9400504D0; GB9300573D0

Abstract

Mobile apparatus for cleaning e.g. heat exchanger tubes includes a ball collector (18) in which a plurality of elastomeric balls may be retained. The plurality of balls may be supplied to a tube to be cleaned using connection means (58, 64), the balls scouring the interior walls of the tube and thus cleaning it. The apparatus also includes pump means (20) for circulating the balls through the tube, and the whole apparatus is mounted on a towable trailer. The diverter (66) may be permanently mounted in the main tube or may be part of the mobile apparatus and placed in line by means of a branch connection and valve arrangement (Fig. 10). <IMAGE>

Description

TUBE CLEANING APPARATUS The invention relates to tube cleaning apparatus, particularly to apparatus for the cleaning of heat exchanger tubes.

It is a particular problem that the tubes of, for example, tube type heat exchangers need cleaning from time to time since otherwise their working efficiency will fall off through the build-up of lime scale and rust. It has previously been proposed to circulate elastomeric balls through the tubes of such apparatus, each ball being an interference fit in the tubes concerned, so that the interior walls of said tubes are scoured clean.

However, such cleaning has previously been done using apparatus permanently associated with the heat exchanger apparatus, largely because it is found that a high velocity of fluid flow is necessary to enable the elastomeric balls to do their work effectively. The large capacity pumps used to operate the heat exchangers have been used to circulate the elastomeric balls through the tubes of the apparatus.

Accordingly the present invention provides a mobile tube cleaning apparatus including ball collector means in which at least one ball may be retained, said at least one ball being usable for circulation through a tube to be cleaned, connection means for connecting the ball collector means to the tube, and pump means for circulating the at least one ball through the tube.

In this way a more convenient apparatus is provided for the cleaning of, for example, tubes of heat exchanges.

Preferably, the connection means includes means for connection to ball diverter means, in use said ball diverter means being for separating the ball(s) from water flowing in the tube being cleaned. Thus the ball(s) may be returned to the ball collector means whilst the water flowing through the heat exchanger and tube being cleaned may remain in the heat exchange system. In a first embodiment the ball diverter means is located in the tube to be cleaned, typically on the downstream side of the heat exchanger. In a second embodiment the ball diverter means is included in the mobile cleaning apparatus.

The ball diverter means may include a valve operable to either permit the ball(s) to pass through the diverter means or to retain the balls in the collection means.

The mobile apparatus may include a towable trailer vehicle provided with road wheels and with hitch mechanism by means of which it can be connected to the towing bracket of a motor vehicle. The pump unit and ball collector may be permanently mounted on said towable trailer vehicle and connected together by suitable pipework.

However, in one embodiment, at least the ball separator or diverter unit may be capable of being dismounted from the trailer vehicle for use.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a side view of mobile cleaning apparatus incorporating a first embodiment of the invention, Figure 2 is a front view thereof, Figure 3 is a plan view thereof, Figure 4 is a diagrammatic view of mobile cleaning apparatus incorporating a first embodiment of the present invention connected to heat exchange apparatus, Figure 5 is a diagrammatic view of mobile cleaning apparatus incorporating a second embodiment of the present invention connected to heat exchange apparatus, Figure 6 is a front view thereof, Figure 7 is a plan view thereof, Figures 8 and 9 are diagrammatic sectional views of items forming part of the apparatus, Figure 10 is a hydraulic circuit diagram relating to the second embodiment, and Figure 11 is a longitudinal section through the item of apparatus shown diagrammatically in Figure 9, and showing how the item may be constructed in practice.

Referring now to Figures 1 to 3 of the drawings, the cleaning apparatus there illustrated is mounted on the flat deck 10 of a towable trailer vehicle provided with road wheels 12. A front portion of an A-frame 14 of the vehicle is provided with a conventional hitch mechanism 16 by means of which it can be connected to the towing bracket of a motor vehicle. The trailer vehicle is provided with brakes, rear lights etc. (not shown) which may conform fully with the requirements of the Road Traffic Act.

The apparatus mounted on the trailer vehicle includes a ball collector unit 18, a pump 20 and pipework generally indicated 22, at least some of the lengths of pipe constituting the pipework 22 being lengths of flexible pipe or being lengths of pipe with flexible end portions or angle joints to enable the pipework to be installed in different arrangements to suit the layout of different heat exchanger installations. The ball collector unit is a device whereby a plurality of elastomeric balls (not shown) can be allowed to circulate in a hydraulic system in which the unit is installed or collected in said unit. As illustrated in Figure 8 the unit comprises a tank 24 in which a conical perforate basket 26 is located to divide the tank into upper and lower compartments.A butterfly valve (or vent valve) 28 is provided in a lower portion of the basket which can be opened to allow the balls to pass freely through the unit or closed to retain said balls in the basket.

Also included in the apparatus is a control panel 50 which is used to control the operation of the pipe cleaning apparatus. For example it may include means for adjusting the speed of operation of the cleaning apparatus.

Figure 4 illustrates the use of the cleaning apparatus in a heat exchange apparatus. The heat exchange apparatus includes a heat exchanger or cooler 52 to which water is supplied via inlet and outlet pipes 54 and 56 respectively. The ball collector 18 is connected via pipe 58 and valve 60 to the inlet pipe 54. Similarly the outlet pipe 56 is connected via valve 62 and pipe 64 to the pump unit 20. Located in a portion of the outlet pipe 56 is a ball diverter 66 (also known as a ball separator unit or a strainer section). The ball diverter 66 separates the balls from the water flowing in the outlet pipe 56 and returns the balls via pipe 64 to the ball collector 18. In this way the ball diverter 66 operates in a similar fashion to the ball separator unit 30 which will be described below. The general operation of the system will be described below with respect to a second embodiment.

Figures 5, 6 and 7 illustrate a second embodiment of cleaning apparatus according to the present invention.

Included in the second embodiment, mounted on the trailer, is a ball separator unit 30 (see Figure 9) similar to the ball collector unit 18. It comprises a tank 32 containing a conical perforate basket 34 and the balls together with a part of the water flow can pass freely through the unit from an inlet 33 to a first outlet 36 whereas the remainder of the water flow can pass freely through holes in the basket to a larger second outlet 38.

Referring now to Figure 10, in the hydraulic circuit there illustrated a heat exchanger, generally indicated 40 has a plurality of tubes 42 which need cleaning from time to time to prevent the build-up of lime scale and rust. Pipes 44 and 46 are part of the heat exchanger installation and carry water to and from the heat exchanger; they are of relatively large bore so that an adequate flow of water through the heat exchanger produced by a pump (not shown) will be maintained.

Shown in chain-dotted lines in Figure 10 is apparatus according to the second embodiment of the invention by means of which the heat exchanger tubes can be cleaned, that is to say, the ball collector unit 18, the pump 20, the ball separator unit 30 and lengths of pipe 22 by means of which the apparatus is connected between the pipes 44 and 46.

The heat exchanger installation is shown to have been fitted with permanent pipe connections 43, 45 and 47 by means of which the cleaning apparatus has been able to be connected to it, said pipe connections being fitted with respective valves V1, V2 and V3 which will all be closed when the apparatus embodying the invention is removed from the installation. (A further valve V4 is provided this being installed in the pipe 46 near the pipe connection 45. Said further valve V4 is closed when the apparatus embodying the invention is connected to the installation for use; it is re-opened when the apparatus has been used and is to be removed).

A downstream end of the temporary pipework 22 is thus connected to the pipe connection 43 and the inlet 33 of the ball separator unit 30 is connected to the pipe connection 45. The second outlet 38 from the ball separator unit is connected to the pipe connection 47.

Relatively short lengths of temporary pipework 23 are used to connect the ball separator unit to the connections 45 and 47 of pipe 46.

The bore diameters of the lengths of pipework 23 are the same as or similar to the bore diameters of the pipes 44 and 46 which are part of the heat exchanger installation. (Said lengths of pipework are, however, relatively short and can thus be accommodated on the towable trailer vehicle without undue difficulty and can reasonably easily be moved into position for use when required).

It will therefore be understood that the same or substantially the same through-put of water can be maintained whilst the cleaning operation is in progress as when the heat exchanger is operating normally. This is important because it has been found that cleaning of the heat exchanger tubes is more effective when a high rate of flow is maintained.

During a cleaning operation, the valves V1, V2 and V3 will all be open and the pump transfers the elastomeric balls from the pipe 46 to the pipe 44 through the relatively small bore pipework 22. As the cleaning operation proceeds, the greater part of the water flowing into the ball separator unit will flow freely through the basket 34 and back into the pipe 46 whilst the balls will be strained out to pass through the pump 20 and ball collector unit 18. When the cleaning operation has been completed, the valve 28 of the ball collector unit will be closed so that the circulating balls will all be collected in said unit. The respective valves carried by the pipe connections 43, 45 and 47 will then be closed and the valve V4 re-opened, and the apparatus shown in chain-dotted lines in Figure 6 removed.

It will of course be understood that at least some of the apparatus embodying the invention may be dismountable from the trailer on which it is shown to be mounted in Figures 5 to 8. However, in some circumstances the apparatus may be used whilst trailer mounted, save for the lengths of pipework by means of which the apparatus is to be connected to the upstream and downstream ends of the tube or tubes which are to be cleaned. Only the lengths of pipework 23 are of very substantial bore diameter. These will therefore be as short as possible and the ball separator unit 30 will be positioned in close proximity to the pipe connections 45 and 47.

In Figures 5 to 8 the motor driven pump unit 20 is shown connected to the ball collector unit 18 by means of pipes 21 and it is convenient if the hydraulic circuit illustrated in Figure 10 (and similarly that of Figure 4) can be set up without dismounting those items from the trailer. In this case the ball separator unit will almost certainly need to be dismounted from the trailer to be connected between the pipe connections 45 and 47 of the pipe 46 of the installation which is to be cleaned.

However, in being positioned towards the rear of the trailer in the illustrated embodiment, there is a possibility of the trailer being able to be backed into position adjacent the pipe 46 of the installation concerned so that the required pipe connections to the ball separator unit can be made without dismounting the latter from the trailer. The precise manner in which the apparatus is used, that is to say which items will be dismounted from the trailer in order to set up the hydraulic circuit diagrammatically illustrated in Figure 10, and how many lengths of pipe 22 will be required to make the necessary connections, will depend upon the layout of the heat exchanger installation concerned Various modifications may be made. For example, in Figure 11 there is illustrated a simplified form of the ball separator unit 30 shown in diagrammatic form in Figure 9.In this practical construction, the tank 32 is formed by a length of full bore pipe, that is to say a bore substantially the same diameter as that of the pipe connection 45 and temporary pipework 23. The conical perforate basket 34 extends some distance along said length of full bore pipe and is connected to the first outlet 36, which in this case is a length of smaller bore pipe extending through the side wall of the full bore pipe, by means of an elbow 35.

Furthermore, instead of the temporary pipework 22 being constituted by the lengths of separate pipe illustrated in the drawings, there will preferably be employed lengths of thick walled plastics pipe, this being sufficiently resilient that it can be used whatever the layout of the heat exchanger installation concerned.

When being transported, a relatively long length of plastics pipe of this kind may for example be coiled around the other items of equipment mounted on the trailer (or in fact if the trailer vehicle is to be towed by a van the length of plastics pipe may be coiled on a drum carried in the van).

Claims

CLAIMS:

1. Mobile tube cleaning apparatus including: ball collector means in which at least one ball may be retained, said at least one ball being usable for circulation through a tube to be cleaned, connection means for connecting the ball collector means to the tube, and pump means for circulating the at least one ball through the tube.

2. Mobile tube cleaning apparatus according to claim 1 in which the connection means includes means for connection to ball diverter means, in use said ball diverter means being for separating the ball(s) from water flowing in the tube being cleaned.

3. Mobile tube cleaning apparatus according to claim 2 in which said ball diverter means is located in the tube to be cleaned.

4. Mobile tube cleaning apparatus according to claim 2 in which said ball diverter means is included in said apparatus.

5. Mobile tube cleaning apparatus according to any of the above claims mounted on a towable trailer.

6. Mobile tube cleaning apparatus according to any of the above claims in which the ball collector means includes a valve operable to either permit the ball(s) to pass through the collector means or to retain the balls in the collection means.

7. Mobile tube cleaning apparatus substantially as any one embodiment herein described with reference to the accompanying drawings.