NO20141141A1 - Procedure and system for cleaning cooling pipes in heat exchangers - Google Patents

Description

The present invention relates to a method and a device for cleaning the fluid-carrying pipes in connection with heat exchangers, as can be seen from the introduction in the subsequent claims 1 and 7. In particular, the aim is to clean the cooling pipe surfaces of heat exchangers of the box cooler type . An application of the method and system is also discussed. With fluid-carrying pipes, one thinks in particular of the pipe circuits that carry the fluid that is to be heated or cooled by heat exchange. In connection with box coolers, these are cooling pipes, where the fluid must be cooled by the surrounding seawater.

Today, a large number of "box coolers" are used on board ships, and these must be regularly cleaned to maintain efficiency. With the current solution for cleaning, the box cooler must be dismantled while the ship is in dock/dry dock, and the cooler flushed clean. See mention later in this description.

Position of the technique:

Regarding the state of the art, reference should be made to the following German patent publications:

DE-10202406 (ERDMANN WOLFGANG

DE20004531 U1 (ANDREAS PEIL)

DE202012007061 U1 (HARALD MUELLER)

DE19725631 C1 (Jahn Frank)

DE10202406 mentions external cleaning of radiators. Placed on the upper side. Liquid-carrying nozzles. On the underside, the liquid is caught in a container and recycled/pumped back to the nozzles.

DE20004531 relates to external cleaning of convectors/radiators. The radiator is surrounded from above by waterproof foil that extends vertically towards an underlying container/bowl for absorbing liquid from liquid-carrying nozzles placed on the radiator's upper side. Here, cleaning can be carried out without dismantling the convector.

DE-202012007061 relates to a device similar to that which appears in DE-10202406. Here, a final treatment is carried out with clean water.

DE-19725631, like the above-mentioned publications, covers flushing of radiators. The rinse water is recycled and can be cleaned using filters.

The listed publications do not relate to the cleaning of box coolers on ships, but cover the external cleaning of radiators using flushing equipment.

It is an aim of the invention to produce a method and device which will make the cleaning of the heat exchanger tubes in box coolers easier and safer than previously known.

The method according to the invention is characterized by an upwardly open bag-shaped envelope being brought to enclose the tube set and its upper opening edge fixed in the exchanger tube set holder unit, and the bag is supplied and filled with cleaning agent which thus contacts the pipe surfaces, after which cleaning agent with the loosened removed impurities is withdrawn from the bag shape, as stated in the characteristic in the subsequent claim 1. The preferred embodiments are stated in the independent claims 2-6.

The device according to the invention is characterized by

- a first unit A comprising an upwardly open bag-shaped envelope (bag) designed to enclose the pipes, and means for attachment to the cooling box, as well as means for connecting lines/hoses for the supply of cleaning agent, and the diversion of the impure cleaning agent.

In one embodiment, said wires/tubes are connected to a second unit B, where

unit B includes a container for cleaning agent, outlet nozzles for connecting hoses to the bag, as well as pump(s) for conveying fluid/cleaning liquid, motor for operating pumps and a filter unit for cleaning and further handling of impure cleaning agent from the bag, and return (recycling ) of purified cleaning agent for the bag, as stated in claim 7. Preferred designs are stated in the subsequent non-independent device requirements.

According to the invention, the method and system according to the preceding claims are used for cleaning heat exchanger pipes in cooler boxes on ships, where the cooler box is placed in a bottom section of the ship, and where an isolated circulation circuit of fluid (gas liquid) is cooled in heat exchange with sea water (fresh water in a lake or sea salt water).

More specifically, the device constitutes a large open bag/bag, which is threaded, from the bottom up, on the outside of the can cooler. The bag is made of a waterproof canvas material. Box coolers are normally attached to the ship, such as in the ship's framework or bulkhead, in the top part of the box cooler so that the bottom and the vertical wall sections of cooling pipe sets are freely exposed and accessible. The bag has fasteners in its top part, and can be fitted in the top part of the cooler, or directly to the ship (framework) above the cooler. The bag now encloses the entire cooler with its heatsinks. Cleaning liquid can be added to the bottom of the bag. The bag gradually fills up with the liquid and the liquid level rises to the top. The liquid will flow around the cooling tubes in each cooling tube set, and will then flow out through the adapted outlet adjacent to the upper rim of the bag. The cleaning liquid, which is thus supplied from below, will now flow around the pipes and clean all the pipe parts in the box cooler.

According to one embodiment, the bag is attached with longitudinal pipelines (indicated as 4 in figure 2), and these are equipped with a number of nozzles for flushing the pipe rods in the box cooler.

Supplying cleaning water from the bottom of the bag or from above with the help of nozzles is also a technique that does not appear in the listed publications.

The invention will subsequently be described in more detail, with reference to the accompanying figures, in which: Figure 1 shows a typical application of cooling boxes on a ship, and for which the present invention is to be used. Fig. 2 shows the principle of cleaning, a system where the bag 1 (unit A) encloses the cooler 3, as the cleaning liquid is recycled (and cleaned) via the container (4), also called unit B, the pump housing. Fig 3 shows in more detail the bag (container) 1 and the pipelines for supply and discharge of cleaning liquid, and the pipelines with nozzles for flushing.

Figure 4 shows a side view of the unit in Figure 3.

Figure 5 shows a cross-section of the bag according to Figure 3, while Figure 6 shows an even larger section of a detail in Figure 5.

Figure 1 shows a typical application of cooling boxes with heat exchanger tubes, placed in the bottom of the ship, and where an isolated circulation circuit of fluid (gas liquid) is cooled in heat exchange with seawater. The figure shows a lower section of the hull/keel part 100 of a ship, where a heat exchanger 110 with heat exchanger pipes 112 assembled in bundles is mounted inside a section 101 in the hull. The bundle of pipes 112 is attached to a frame 113 in an overlying deck 114, and is free-hanging downwards in the room 101 where seawater from the outside can flow freely in and out through opening grates/grilles 115 or 116 in the hull side and/or the bottom of the hull .

The heat exchanger unit 110 includes the necessary equipment at the top, such as a pumping station to bring the fluid to flow through the cooling circuit, or this can be carried out from other places in the ship. The top plate 113 comprises an outlet which is connected to each pipe.

In the specific case, the fluid (liquid/gas) in the pipe circuits 112 will be cooled by the colder seawater. The cooled fluid is then used for various cooling needs inside the ship, such as in cold rooms and to operate air conditioning systems on board.

Since the cooling pipes are contacted with seawater from the free seawater mass, a coating (scale) forms on the surface of these pipes 112, which over time reduces the heat exchange capacity. There is therefore a need to clean the pipes at regular intervals.

Today this is done, for example, by the entire pipe circuit 112 with the frame 113 having to be dismantled and removed from the ship to then be flushed clean with cleaning agent at a suitable cleaning station, after which the frame with pipes is screwed back into the deck 114 and the heat exchanger can be used again.

This has proven to be a time-consuming and expensive process, and it is an aim to produce an improved cleaning method.

In particular, it is a purpose to be able to carry out the cleaning without having to dismantle the frame with the pipe circuits 112.

Figure 2 shows a system that will fulfill this, i.e. without disassembling the pipe circuit. The figure shows the system's two units A and B.

Unit A comprising a bag for enclosing the cooling tubes, and means for attachment to the cooling box

Unit B includes container for cleaning agent, outlet nozzles for connecting hoses to the bag, as well as pump(s) for conveying fluid/cleaning liquid, motor for operating pumps and a filter unit for cleaning and further handling of unclean cleaning agent from the bag, and return of cleaned cleaning agent for the bag.

The unit A comprises a bag, sack or an upwardly open tight container 1 with means for supplying and withdrawing cleaning liquid to the space inside the bag. The figure at A is shown with the bag enclosing the exchanger tubes 112.

Unit B is a box-shaped apparatus - with a pump housing - and which includes a series of instrumentation for handling cleaning agent, chamber for containing clean cleaning agent, chamber for returned impure cleaning agent, and filter set for removing impurities, pumps and motor(s), so as electric motors, for operating these, for recycling cleaning agent.

These instruments are mounted in a stand 40 (figure 2), preferably with legs fitted with wheels, and include connectors for connecting hoses leading to and from the bag, a pump to feed the cleaning liquid into the bag in unit A through suitable lines- / hoses (the two circuits shown in figure 2), and to receive the cleaning liquid with the impurities from the pipe surfaces in return. The box also includes a cleaning unit in the form of a filter set that removes the impurities and a storage chamber for cleaned cleaning liquid which can then be returned to the bag, i.e. that a recirculation of cleaning liquid is created.

Box B is a mobile unit that is easy to carry with you, as hoses can easily be connected to and disconnected from, and extended to the bag construction (unit A) for connection to this.

As a cleaning agent, liquid such as water or suitable liquid chemicals can be used, and which may contain additives/substances that can promote the cleaning of the pipe surfaces for scale (marine shells) and impurities. The system also has the option of producing a cleaning liquid such as hot water, with a suitable temperature of up to 89-90 degrees Celsius.

The top plate 113 and cooling tubes 112 are shown at the top of unit A in Figure 2. The top plate 113 may be a hollow box, i.e. the same 113 shown in Figure 1, and may form part of the attachment mechanism for temporarily attaching and holding the top edge of the bag 1 in place. Down under the plate 113 protrudes the set of cooling pipes.

In Figure 2, the bag 1 is placed up and around the cooling box 112,113. Bag 1 is a dense plastic-like cloth that is open at the top. Around the upper edge 11 of the bag 1, a frame form 12 is integrated, which is used when attaching to the cooling box, and which helps to keep the opening open. At the bottom of the bag 1, i.e. adjacent to the bottom of the bag 14, a pipe connection 13 is integrated for connection to external hose 5 from unit B for delivery of cleaning agent to the bag or withdrawal from the bag. In the upper part, at the edge 11, a pipe connection 15 is also integrated for delivery/withdrawal of cleaning agent to/from the bag through the hose 9 back to the pump housing B.

The bag 1 is made of a flexible waterproof cloth, particularly reinforced flexible plastic cloth, which can thus be easily mounted on and around the cooling pipes. Such a design is necessary since it must be adapted to be moved into the chamber 101 in the bottom part of the ship, under tight space conditions, to then be positioned under the cooling pipe set 112, and then pulled up and around the pipe set 112. There is a great advantage of the invention that the bag 1 used for cleaning has such a flexible shape, i.e. that it is very easy to assemble and disassemble after the cooling pipes have been cleaned.

In addition to the fact that liquid can be introduced via the pipe connection 13, the system also includes that the framework to which the bag's upper edge 11 is attached comprises a number of pipes with spray nozzles which are brought to spray out the cleaning liquid more directly against the cooling pipe surfaces. In the example in Figure 1, three such mutually parallel tubes 16,17,18 are shown, where the two outermost ones, no. 16 and 18, lie parallel to each of the longitudinal edges of the opening of the bag 1, while the middle tube 17 lies in the middle above the opening of the bag 1. The tubes are assembled in a square frame shape using transverse rails 27 and 29, one at each end of the bag's edge-edge opening, see figure 2. It appears from figure 6 that the rails around the perimeter include a number of fastening eyes or holes 31 which are used to attach the bag construction 1 to the cooling pipe frame 112, so that the bag sits stably in place and can withstand the weight of the water filling the bag 1.

When the cooling pipe loops in a box cooler can include units with a given mutual distance at the top of the bag, the frame formed by pipes 16-17-18 and the rails 27,29 can be moved upwards to some extent so that, for example, the middle pipe 17 is located between two such cooling pipe units, cf. as outlined in figure 3.

The three pipes 16,17,18 are fluidly connected with a common supply hose 7 from the pump box A. From a common manifold connection at 19, branching hoses 19,20,21 respectively lead further into the parallel pipes 16,17,18. Each parallel pipe includes a number of nozzles with spray nozzles 125 which are aligned to spray against the pipe surfaces.

This means that cleaning agent can be added to the top 15 of the bag 1, and withdrawn from the bottom 13, or vice versa. The most preferred is to supply the cleaning agent into the bag 1 via the bottom pipe connection 13, and draw off the cleaning agent with impurities from the top pipe connection 15. By pumping the cleaning agent in at the bottom, you achieve that the impurities that float up can be collected in an upper layer of the liquid in bag 1.

By pumping the cleaning liquid into the bag 1 with a suitable pressure, like a powerful jet, a circulation is obtained in the liquid around the individual pipes in the cooling circuit 112, which enhances the cleaning of the pipe surfaces. In addition, the liquid can be water containing particularly cleaning additives, for example soap substances, which improve cleaning.

By the existence of the pipes 16-18 with the spray nozzles, the cooling pipes 112 can thus be cleaned in two modes. One is that the cleaning agent is pumped in through the pipe connection 13 and drained via the pipe connection 15, at the same time that the cleaning agent is sprayed against the cooling pipes through the nozzles 125.

When starting the cleaning, one mode could be to pump in liquid until bag 1 is completely filled, and then stop the pumping and let the liquid in bag 1 stand still for a while and let the liquid act to clean the pipe surfaces, before the liquid with the impurities ( such as solid flakes, particles, or liquid-dissolved impurities, is drained from the bag.This filling mode can then continue until the tubes 112 are surface clean.

Bag 1 can then be emptied completely and it can be disconnected from the cooling box inside the chamber, after which the cooling box can resume its normal heat exchanger function in the ship.

With the present invention, where a flexible upwards open bag is used to cover a cooler box, a solution has been produced which eliminates the time-consuming and expensive cleaning solutions that have been used up to now. It therefore represents a major advance in this area of cleaning refrigerated boxes.

Claims (12)

1. Method for cleaning a tube set (112) in a heat exchanger mounted in a holder (113), where the tube set is brought into contact with a liquid cleaning agent to remove impurities from the tube surfaces in the tube set, characterized by an upwardly open bag-shaped envelope (1) is brought to enclose the tube set and its upper opening edge is fixed in the exchanger tube set (112) holder unit (113), and the bag is supplied and filled with cleaning agent which thus contacts the pipe surfaces, after which cleaning agent with the loosened removed impurities is withdrawn from the bag form (1). 2. Method in accordance with claim 1, characterized in that the cleaning agent is introduced into a lower part (13) of the bag into contact with the pipes (112), and is withdrawn, together with the impurities, from an upper part (15) of the bag. 3. Method in accordance with claim 1, characterized in that the cleaning agent is sprayed out through adapted nozzles (125) and directly onto the pipe surfaces, when supplied via a separate cleaning agent circuit (7 -19,20,21 - 16,17,18). 4. Method in accordance with claim 3, characterized in that the cleaning agent is sprayed out through adapted nozzles (125) arranged in the upper part of the bag form (1). 5. Method in accordance with one of the preceding claims, characterized in that the cleaning agent is supplied to the two circuits by pumping from a common pump unit in the unit (pump housing) (B). 6. Method in accordance with one of the preceding claims, characterized in that the return of impure cleaning agent is received in the unit (B) and recycled by the impurities being separated and taken care of, while clean cleaning agent is returned to the cleaning agent circuits for supply to the bag (1). 7. System for cleaning a fluid-carrying tube set (112) in a heat exchanger mounted in a holder (113), characterized by- a first unit A comprising an upwardly open bag-shaped envelope (bag) (1) designed to enclose the tubes in the tube set, and means for attachment to the heat exchanger, as well as means for connecting lines/hoses for the supply of cleaning agent, and diversion of the impure cleaning agent. 8. System in accordance with claim 7, characterized in that wires/tubes are connected to a second unit B, where unit B comprises container for cleaning agent, outlet nozzles for connecting hoses to the bag (1), as well as pump(s) for conveying fluid/cleaning liquid, motor for operating pumps and a filter unit for cleaning and further handling of impure cleaning agent from the bag, and return (recycling) of purified cleaning agent to the bag (1). 9. System in accordance with claim 8, characterized by the unit A with an upwardly open bag (1) is arranged to enclose the pipe set, and comprises an inlet (15) in the lower part for the supply of cleaning agent, and an upper outlet (13) for removal of cleaning agent, ie the two inlets (13) and outlet (15), respectively, are connected to associated lines connected to the unit (B) for cleaning agent, in a first cleaning agent circuit, and which includes pumps for conveying cleaning agent through lines/hoses, as well as Altar equipment for removing impurities in used cleaning agent , so that clean cleaning agent can be recycled to the bag (1). 10. System in accordance with claims 7 - 9, characterized by a further cleaning agent circuit, comprising a number of tubes with spray nozzles which are arranged connected to the bag (1) carrier frame (16-17-18; 27,29) in its upper part, and includes nozzles with spraying nozzles (125) which are aimed at the pipe surfaces (112). 11. System in accordance with one of claims 7-10, characterized in that the bag (1) is made of a flexible waterproof fabric, in particular reinforced flexible plastic fabric, which is thus easy to mount up and around the cooling pipes, as the upper part of the bag (1) is 12. Application of the method and system according to the preceding claims, for cleaning heat exchanger pipes in cooling boxes on ships, where the cooling box is located in a bottom section of the ship, and where an isolated circulation circuit of fluid (gas liquid) is cooled in heat exchange with seawater.