FR2477278A1 - METHOD OF CLEANING PLATE EXCHANGERS AND DEVICE FOR IMPLEMENTING THE METHOD - Google Patents

Abstract

1. Apparatus for cleaning parallel plates of heat exchangers by mean of rotating brushes motor-drived, characterized by the fact it is comprising : a movable frame (7) supporting at least one truck (10) able to go down and up, each truck (10) being provided with platforms (13) bearing motors (14) of which each drives a pair of brushes (16), the lot of platforms, motors and brushes being able to rock round a shaft (17) perpendicular to the moving course of the trucks (10), the frame (7) bearing moreover parallel masks (18) which turn around an axle (19) placed at the lower part of the frame and parallel masks (18') which turn around an axle (19') on the upper part of the frame, the two axles (19, 19') remaining parallel to the swinging-shaft (17) for the brushes.

Description

The present invention relates to cleaning devices

  exchangers and more particularly mobile cleaning stations.

  It is known that in plate exchangers, commonly used

  for example in thermal power plants or refineries, the circulation of

  The formation of liquids is often accompanied by the formation of deposits on the surface of walls and plates and the thickness of these deposits increases with time. The presence of deposits reduces the heat exchange and the

  reduction of the heat transfer coefficient can not be compensated

  see that by slowing the flow of fluids what

  IO leads to a reduction in plant efficiency.

  Therefore, it is essential to carry out periodic cleaning of the exchanger. However, this cleaning must be fast and

  do not cause a long service interruption.

  So far, the plates of the exchangers have been cleaned by

  manual brushing. These cleaning operations are generally relative

  long. Of course, cleaning can also be done by the injection of a suitable chemical, but the result is not always the expected one and the discharge of polluted water implies

  often a special treatment of these.

  Thus, an object of the invention is to provide a rapid method of cleaning the plate of the heat exchangers,

  Another object of the invention is to provide a device permitting

  putting automated cleaning of plates.

  Another object of the invention is to provide a device

  effective cleaning, only by means of mechanical scrubbing

  and wash with water. Indeed, it is desired to avoid any stripper or chemical that could become a contaminant in-a

  nuclear power station or refinery.

  This goal is achieved by using a cleaning method essentially comprising the following steps: the pre-separation of the plates to be treated, the establishment of a cleaning device provided with low and high masks and brushes, the tilting- low masks and their blocking, the tilting of high masks and their blocking, the separation of the masks high and low, the tilting of the brushes and 3.5 their blocking, the translation of brushes from the bottom to the top of the surfaces of the plates and from top to bottom low, while they are rotating and that water is projected, then the swing ofbrushes and

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  masks in reverse and moving-treated plates.

  With this method, the various steps are performed very quickly since they are automated. According to the state of the surfaces

  to clean the water from the ramps is sent to an appropriate pressure.

  In addition, several cylindrical brushes are used. A brush is applied against a surface of the plate to be cleaned and a

  another brush is applied against the surface of the next plate.

  This pair of brushes is actuated by a single motor provided with a gear such that the first brush rotates in the opposite direction to the direction of rotation of the second brush. The brushes are all parallel and during the cleaning cycle they go up and down along the plates to be cleaned. Thus, thanks to the device according to the invention, the complete brushing of each plate face is carried out in a few seconds. Since several pairs of brushes are used, several plates can be brushed simultaneously, which further increases the speed of cleaning.

  In general, four pairs of brushes are preferably used.

  - We can clean eight faces of plates at the same time. This number of

  brushes is of course not limiting.

  Moreover, the spacing of the masks makes it possible to apply them against the joints of the plates and to keep the latter in the separated position. Masks have any shape such as poeition

  tipped, they come to cover the plate joints of the exchanger.

  In addition, as the brushes and masks can occupy a rest position, that is to say that they are not tilted, one can

  bring the cleaning device in front of the plates. These plates are-

  spaced parallel and as the brushes and masks can tilt, they come to be interposed-between the plates to proceed on the one hand cleaning the plates and on the other hand to the protection of the joints. Masks have an additional function which is to maintain

  the plates of the exchanger in the separated position.

  Of course, it is also possible to interpose between the spaced plates, in a water projection system which allows to drive the detached solid particles by brushing. We can, if desired, project strippers. However chemicals are to be avoided for the cleaning of nuclear power plant heat exchangers, any contamination to be avoided. The possibility of having a significant water pressure replaces

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the addition of stripper.

  The following description, with reference to the attached drawings

  a non-limitative example, will help to better understand how

  The present invention can be practiced.

  FIG. 1 is a front view of a heat exchanger at

  plates during a cleaning cycle.

  Figure 2 is a side view of a cleaning device.

  according to the invention, in the rest position.

  Figure 3 is a sectional view along the line III-III of the exchanger of Figure 1, which is cleaned by a device according to the invention. FIG. 4 schematically represents the means used to bring brushes intended to clean a heat exchanger

according to Figure 1.

  In Figure 1, we see an exchanger I consisting mainly of a multitude of parallel plates 2 and slidable along the slide 3a. These plates are generally provided with openings

  3. The liquid to be cooled circulates between the

  2 while a cooling fluid circulates in a different direction

  for the flow of heat to be transmitted from one fluid to another.

  The liquid flowing between the plates is usually water.

  As a result, deposits may form on the face of each plate wall, the thickness of which increases with time. To make

  cleaning, use the post below according to the invention.

  This device 4 (see Figure 2) is movable by two wheels that move in a rail 6. A frame 7 rests on the wheels and the wheels 8 which are parallel to them. U-shaped brackets 9 support two carriages 10 which can be raised or lowered along the brackets which are provided with rollers or wheels. The driving shaft It drives a chain 12 which itself actuates the carriages 10. These

  the last are provided with trays 13 supporting four motors 14

  each dragging two shafts 15 in opposite directions, by means of a gear

  swimming (not shown). Each shaft actuates a 16-cylinder brush.

  drique. Therefore, the device has eight brushes rotating in pairs in opposite directions. The trays 13 are connected by trays bearing supports (not shown). In addition, they can rotate around the tilting shaft 17. The angles 9 are fixed on a high frame 7 '; Chassis 7 and 7 'are each connected to eight masks 18 and 18'. Each mask 18 and 18 'is mobile around

  axis 19 and 19 'and can move from the vertical position (representing

  in solid lines in Figure 2) d the horizontal position

  (shown in broken lines). All the masks 18 are parallel

  _5 leles and equidistant, as well as masks 18 '.

  To clean a plate heat exchanger, the following procedure is carried out: the plates are spread apart so as to leave four gaps 20. The mobile cleaning station 4 is then brought, allowing it to roll in the rail 6, in front of the spaced apart plates . These preliminary operations are not automatic but we understand that they can become so if necessary. The mobile station is not

  motorized in this embodiment. However, we also conceive

it can be.

  The automatic cleaning cycle starts therefore. The eight masks tilt around the axis 19, according to the arrow B (Figure 2). The masks are rotated by means of four jacks 2i (FIG. 4), each rod T of which is fastened to one end 23 of the rigid rod 24, the other end 22 of which is fixed to the mask 18. The end 23 undergoing translation the mask 18 is rotated. To tilt the mask in the direction of arrow B it is enough to act the cylinder

  21 in the opposite direction. ' We keep the masks down in this low position.

  abutment, so that the joints 3 are constantly protected. This block

  The cage is made by means of spines, the stems of which come into a hole in the masks. These locking cylinders of the lower masks are four in number. Tilt cylinders and

  * blocking are attached to the side 7 carriages.

  Top masks are similarly tipped

  in the direction of arrow B 'to protect the joints 3 superior

  laughing and are stuck in this position. Finally, the masks are

  spaced and are plates against the plates of exchangers they maintain-

  are spaced apart by two jacks.

  The plates 13 as well as the motors 14 and the eight brushes 16 then rock around the shaft 17, according to the arrow C, thanks to a system of cylinders similar to the jack system used for the tilting of the masks. Likewise, the plates 13 are blocked in

  working position, using .verins. -

  The brushes are therefore in the position shown on the

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  Figures I and 3 and the masks are in the position shown in Figure 3. As seen more in detail in Figure 1, a brush 16 rotating in the direction S rubs against the face 25 of a plate and the brush 16 The conjugate which is driven by the same motor rotates in the opposite direction S 'while rubbing against the face 25' of the next plate. In order to completely sweep the surface of the plate face,

  the brushes are translated in the direction of the arrow 7 (FIG.

  re 2 and 3) and climb to the top of the plates, thanks to the motor shaft II and the chain 12. The brushes come down again to perform a complete cycle. While the brushes rotate

  and their translational movement, water is sprayed through

number of nozzles 26.

  When the movement of brush back and forth is complete, the plates 13 supporting the brushes swing in the opposite direction of the arrow a, then the low and high masks are removed from the plates and finally the high masks return to the vertical position; the

  Low masks then return to their upright position.

  The cleaned plates are moved to the left and

against the previous ones.

  The masks are made of stainless steel. Of course, they can be of any shape and need only to protect the joints, usually of rubber, arranged around the openings

between the plates.

RE V E N D I C A T I 0 N S

  1. A method for cleaning parallel plates of heat exchanger, characterized by the implementation of the following steps: the pre-separation of the plates to be treated, the establishment of a cleaning device with low and high masks and of brushes, the tilting of masks down and their blocking, the tilting of high masks and their blocking, the separation of the masks low and high, the tilting of the brushes and their blocking, the translation of the brushes from bottom to top of the surfaces plates, then from top to bottom, while they are rotating and that water is projected i tilting brushes

  in the opposite direction, the reconciliation of the low and high masks, the

  masks in the opposite direction, and finally the movement of

treated plates.

  2. Method according to claim 1, characterized in that the displacement of the plates and the establishment of the cleaning device

are possibly automated.

  3. Method according to any one of claims 1 or 2,

  characterized in that the plates are moved parallel to each other

to each other.

  4. Method according to any one of claims 1 to 3,

  characterized in that the spacing of the masks makes it possible to apply them

  -on the joints of the heat exchanger plates and to maintain these

in a remote position.

  5. Device for applying the cleaning method according to

  any of claims 1 to 4, characterized in that

  comprises: a movable frame (7) supporting at least one carriage (10) which can lower or rise, each carriage (10) being provided with trays (13) supporting motors (14) which each cause a brush (16) , the set of trays, motors and brushes swinging about a shaft (15) perpendicular to the direction of travel of the carriages (10), the frame (7) further supporting parallel masks (18, 18 ') rotating about an axis located at the lower part of the frame, and parallel masks rotating about an axis (19, 19 ') located at the upper part of the frame, the axis of rotation (19) of the masks low and the axis of rotation (19 ') of the top masks being parallel to the tilting shaft of the brushes.

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  6. Device according to claim 5, characterized in that

  each motor (14) rotates a brush (16) and rotates

opposite a brush nearby.

  7. Device according to any one of claims 5 or

  6, characterized in that the brushes (16) and their support (13)

  slow by means of jacks fixed on the carriages.

  8. Device according to any one of claims 5 or

  6, characterized in that the masks (18, 18 ') are tilted by means

  of jacks fixed on the chassis (7).

  9. Device according to any one of claims 8 to

  9, characterized in that the masks (18, 18 ') are constituted by plates whose conformation is such that, in the tilted position, they cover the joints (3) of the plates of the exchanger

to clean.