Patent Application
20170114560
This invention refers to a floor and wall cleaner specially designed to be used in critical areas with difficult accessibility or restricted access, such as pools for housing a reactor vessel at a nuclear power station, in which human presence must be avoided as far as possible and, should this be necessary, this must be for the shortest possible time.
According to the invention, the floor cleaner comprises:
The pools in which the reactor of a nuclear power station is housed are made up of a cubicle which may be in a regular or irregular shape and have dimensions that can range from one or two dozen metres on the smallest horizontal side to several dozen metres on the larger side, with a height of several metres, able to temporarily house a large number of the components of the reactor in the dismantling stage.
The base of the pools tends to be of irregular shape. On one hand there are small-sized recesses which have to be cleaned preferably before emptying the pool, as these could contain radioactive material, and there are also uneven parts of the floor, amongst other reasons due to the bolts for holding the vessel of the reactor.
This thus requires a device for cleaning the floors of the pools in which reactors of nuclear power stations are housed which is able to clean narrow spaces, to the maximum width of the apparatus and which is able to get over any small obstacles which it might come up against.
As well as the floors, particles are deposited on the walls of these pools. Conventional devices are not nevertheless able to clean the walls, as if they did so it would be the suction force of the absorption system which would have to keep the device attached to the wall. Since these devices have to be made as far as possible of stainless steel or some other material able to be decontaminated, they have a high minimum weight, and the absorption systems conventionally used are not able to maintain their grip. Furthermore, even when the absorption capacity is enough to maintain a grip, any irregularity or space would cause loss of adherence, and the device would fall to the floor and have to be positioned again. Since the positioning task is extremely delicate, this risk in an installation of this sort makes such a system inoperative.
There are different types of floor cleaners. First of all there are manual cleaners, which have a rod with which the cleaning head is moved; this head is connected by means of a suction hose to a pump and normally to a filter to be returned to the pool. This type of cleaners cannot be used in the vessel of a nuclear reactor due to several problems:
EP 1472425 describes an independent floor cleaner for pools which comprises a set of support wheels and is provided with filtration and pumping means. It does not have means of controlling the movement at will.
A robot device known on the market as “ZODIAC Sweepy M3”, comprises a pair of lateral drive chains driven by motors and also comprises a motor for pumping water through a filter. The cleaning width is nevertheless interior, between the drive chains, for which reason it ends far from the outer edges. Furthermore, since this is conceived for cleaning swimming pools, it is not designed to get over obstacles.
In the nuclear industry, the “WEDA N600” device is also a compact device able to be handled in remote control or in automatic mode, which has, like the previous one, a pair of drive chains, in this case with front and rear brushes of a width roughly equal to that of the body of the device and in which the extraction system installed in the apparatus itself expels the water through filter bags.
The “ATOX underwater bottom cleaner” device has a structure similar to the previous ones, in that this is provided with lateral drive chains, with a filtration body operated with an exterior pump. One major disadvantage of this device is its weight, apart from the difficulties of cleaning the side zones, for the reasons given above.
Other devices, even whilst complying with some of the characteristics described in the devices mentioned, are machines with a greater size, weight, cost and with the disadvantages also described above, without the manoeuvring capacity which is intended to be solved with this invention.
Furthermore, any of these can be held up by a small obstacle, such as a bolt head two or three centimetres high, when said obstacle is not directly confronted by one of the drive chains.
An automated pool cleaning vehicle has been disclosed by US 2012/102664 A1, with a housing defining an interior having a pump and a filter bag. The bottom is normally concave. It includes a first and a second pair of wheels connected to the chassis, and also at least a middle roller. Contrary to the teachings of the present invention where the central rollers have a cleaning function in addition to the translation function, the rollers in US 2012/102664 A1 do not have a cleaning (bristling) function but just a translation function, and operate to overcome some kind of obstacles such as steps in a swimming pool. Since it is not conceived for nuclear installations, plastic parts can be used creating a light weight, so the suction force can keep it adhered to the walls. When failure of adherence is encountered, for example when a void portion is found and the suction do not keep the vehicle attached to the wall, the vehicle falls down to the bottom of the pool. The structure therefore does not contain a floater to approximate the resultant density when submerged to that of the water, and have not government means which allow the device to be positioned in a desired position. The rollers are at traction device not having a rotatable roller cleaner different than the traction system
WO 2013/30005 A1 discloses a device for use in nuclear installations. Since it must be manufactured with metal parts it has a substantial high weight. It comprises a pump with a nozzle connected to it and arranged to face surfaces to be cleaned. It comprises adjustable flotation means. The floater as designed is not capable to keep the centre of gravity of the device, so when found an obstacle or a void portion in the pool which reduces the suction this device also falls down to the bottom of the pool or must be supported by an external crane.
There are light swimming pool cleaners made of plastic materials which are able to go up the walls of pleasure swimming pools, but which are not usable in the pool of a nuclear power plant reactor for the reasons stated above, since plastic is not an acceptable material for said use, and neither do they have devices for controlling their movement.
None of said devices is able to efficiently clean the walls of the vessel of a nuclear power plant reactor in a controlled manner.
It is furthermore desirable for the same apparatus which is able to clean the walls to be able to clean the floor. This has advantages in the cost of the device, since instead of two (one for the walls and one for the floor) one will be enough and the operations can be performed consecutively with no need to perform two decontamination processes; one of these is enough at the end of both operations, for cleaning the floor and the walls.
It is furthermore desirable for the same apparatus to be suitable for cleaning sloping surfaces.
The invention being proposed consists of a floor cleaner which comprises a structure carrying the other items, which are as follows:
For proper cleaning of the floor, there are central interior rollers and front and rear exterior rollers. In particular, according to the preferred embodiment, two interior rollers are used, with the suction bell between them, and two exterior rollers, each of these, the front and rear ones, being placed on a hinged support in a normally central position. The interior rollers have a smaller size than the width of the cleaner, insofar as these are driven from at least one of their sides and between the drive system. The outer rollers are divided into two portions, and driven from the centre, so that the free end of each side reaches the maximum width of the cleaner; in particular the length of the rollers is slightly greater than the width of the cleaner casing.
The rollers are made up of a core and a sheath. It has been found that an ideal sheathing for proper cleaning is made up of rubber strips, arranged radially (in a transversal direction to the movement). Hence, at least some of the strips will have to be positioned radially in respect of the roller axis. These transversal strips may be joined to strips arranged on a plane perpendicular to the axle of the roller without impeding their operation.
In normal operation, with no obstacles, the exterior rollers and interior rollers turn in a direction so as to move the dirt towards the interior of the suction bell, that is, they drag the dirt along the floor towards the interior of the suction bell. The displacement is caused by the drive belts. The movement of the front belts and of the rear belts in this normal operation will be in mutually opposite rotation directions; however, when they come up against an obstacle, one of the rollers may possibly have a support which exerts significant force, so that the movement inverse to its displacement could block the floor cleaner, without the drive belts having sufficient support. For this reason, since the front rollers and the rear rollers are driven by independent motors, in the event of their coming up against an obstacle, such as a bolt head or a drop or rise in level of some centimetres, all the rollers may be made to run in forward motion, that is, in the same rotation direction as the wheels or drive belts, which helps to get over the obstacle in question.
The movement of the rollers is separate from the displacement movement of the cleaner, and is driven by two independent motors, as has already been said. The control device can nevertheless synchronise the motors for optimum operation.
For the movement of the rollers and the drive belts, there are respectively motors and mechanical transmission assemblies, each formed of a plurality of pinions engaging each other.
As has already been stated, the exterior rollers are driven from the central part; this central drive is made up of an arm or support which houses a mechanism, and sustains the corresponding parts of the lateral roller projecting outward, up to a width slightly over that of the casing. This means that the exterior rollers do not properly clean a central zone in which the support and the drive mechanism for the front and rear rollers are located, which is why this zone has to be cleaned by the interior rollers. The sheath of the interior rollers must thus be continuous on the longitudinal plane on which the mechanism for driving the exterior rollers is located, especially the front rollers.
Throughout the cleaning process different obstacles may come up, such as screw heads, bolt covers, etc. These obstacles do not tend to be over 2 or 3 cm in height but no compact conventional system is able to overcome these without getting jammed. If the arm carrying the front or rear rollers were rigidly fixed to with the housing of the cleaner, this would make it jam, since on rising up the obstacle, it also undesirably raises the drive belts, and the device loses traction. For this reason it has been designed for both the front arm and the rear arm to have a hinged support, and be subject to an elastic retaining tension, so that the elevation tension is lower than the cleaner's effective weight in the water and so that when an obstacle is reached said arm rises over the obstacle and the cleaner continues its travel and after the obstacle is reached by the drive belts, these are indeed able to get over this with no further problems, the arm returning to the normal working position when the elastic tension caused on reaching the obstacle has been released.
Sometimes small obstacles are nevertheless located in the centre of the cleaner and are not reached by the drive belts. To solve this drawback, at least one of the rollers, and in particular all of these, have been provided with a set of wheels joined to their axle, so that when the cleaner comes up against an obstacle, these wheels continue to pull. The wheels have a smaller diameter than that of the corresponding brush, so that they will not have contact with the floor unless an obstacle with sufficient height is found. This guarantees that the cleaning is correct in routes with no obstacles. Since the rollers are driven by independent motors, two by two (one for the front ones and one for the rear ones) when an obstacle is reached which holds up the floor cleaner, all the rollers will rotate in the same direction, the wheels of said rollers thus pressing on the obstacle and easily getting over this.
According to a less preferred option for embodiment, the wheels of one of the rollers can be freely rotating, independently of the roller movement.
The alignment of the support wheels of the interior rollers with the position of the arm holding the mechanism for driving the exterior rollers should be avoided, insofar as said exterior rollers do not reach the position of said supporting arm.
The suction head is placed held on the cover of the structure, and comprises an upper suction mouth which is connected to a suction pump, either directly or through a conduit; if this is joined to a conduit, a connector is provided, freely rotating at both ends and in a central zone also at 45°, allowing the positioning of the conduit with no restriction both from the upper head and from any lateral position.
The structure is made up of lateral elements and means of joining said elements; it also comprises an upper cover holding the suction head, and protectors or covers at the front and rear, essentially symmetrical except for the holes for the corresponding connectors. The structure is closed at the front and rear by the corresponding rollers. According to one option each of the lateral elements is formed of a pair of separate parallel plates which define a chamber housing mechanical transmission and possibly drive assemblies.
Even when a turbine has been used for the cleaner to grip the floor in embodiments prior to this invention, this is insufficient. Furthermore, since the suction bell is in a central position, a turbine has to be displaced from said centre, and although this is not critical in cleaning floors, it causes unwanted imbalances when this has to clean walls, which could make the cleaner fall to the floor, requiring further repositioning. The floor and wall cleaner of the invention is thus provided with at least a pair of turbines, which may run simultaneously or independently. The use of turbines for adherence placed symmetrically in respect of the longitudinal and/or transversal central plane has been shown to have a satisfactory result, which cannot be achieved with a single one.
Since the device may be used in a dark zone, such as the pool of reactor vessel at a nuclear power plant, the cleaner is designed to have lighting means, at least in the forward motion direction, but possibly also for reverse movement.
It is also designed for this to have at least one camera and possible two, one at the front and one at the rear, so that the state of cleaning achieved can be known at all times as well as the directions to be taken.
One of the problems for keeping the cleaner on a wall is the weight of the device. As already stated, plastic materials cannot be used in operations in radioactive zones, for which reason the cleaner has a significant weight, of several dozen kilograms.
For this reason the casing has been provided on both sides with two supports for joining this to a float. The float has the aim of compensating part of the cleaner's weight. In particular, it has been designed to have a pair of supports on each side, so that when only walls have to be cleaned, the alignment of the float is roughly over the centre of gravity of the cleaner. When this has to clean sloping surfaces the anchorage could nevertheless be hinged, or arranged in any other position.
The float comprises a normally prismatic sealed body, with a fixed volume, when the apparatus is operating. This sealed body can also comprise an inflatable interior membrane. It is designed to have inlet/outlet valves for cleaning or ballast, normally with water, when the volume required for the specific application is lower than the total volume of the chamber. This float exerts an upward force of from 40% to 90% of the weight of the cleaner, according to the design specifications, apart from overcoming its own weight. Furthermore, to regulate proper operation of the ascending and descending operations it has also been designed for the body to be provided with a second chamber fitted with an inflatable membrane, with a variable body which totally neutralises the weight of the body or even which makes this float. This second chamber is made with perforated sheet metal, so that when the membrane inflates, any water found inside said second chamber can easily be drained out.
The cleaner comprises an electronic control system. The electronic control system determines the actions of speeds and movement directions of each of the motors for driving the displacement or movement of the rollers and the turbine, of the lighting and picture-taking elements, or indicates any fault which might arise in the device. The electronic system comprises a sealed connection plate for connecting electric supply and control cables of the device.
The control body is placed outside the device, and joined to this by means of supply cables for the different elements, insofar as it been shown that the radiation received in the pool quickly disables some of the functions. The governing system is normally placed in a remote control unit, which is normally a computer. This could possibly have an intermediate unit, for example a float which minimises the requirements of control cable sections, when the distances are too long, and which also enables control by means of wireless means.
In order to illustrate the following explanation, ten sheets of drawings are attached to this descriptive report, representing the essence of this invention in eleven figures, and in which:
The following reference numbers are used in said figures:
The invention being proposed consists, as stated in the heading, of a floor and wall cleaner, governed by remote control, suitable for use in cleaning the floors and walls of the pools housing the vessel of nuclear power stations.
This is made up of a drive and cleaning body (100) and a floatation body (200).
The drive and cleaning body (100) is mainly made up of components of stainless steel and comprises the following elements:
In this configuration, the drive and cleaning body (100) has a maximum width of roughly 32 cm and a length of roughly 41 cm, and has a floatation body roughly 90 cm long, which allows great manoeuvring capacity and can reach recesses which would be impossible for other devices due to their dimensions and structure.
To give the cleaner the required floatability to be able to move along a wall or sloping surface, normally from the top downwards, it has been designed for said cleaner to comprise a floatation body (200). The floatation body (200) is formed of a casing or housing (201) with at least one first sealed chamber, which can also be provided with an interior inflatable membrane. This first chamber is provided with inlet/outlet connections for filling/emptying and interior cleaning. This will normally be full of air, but in some applications, or to be used with a lighter body, it may be partly full of water, the rest being air, which means that the float force can be regulated. The floatation body (200) is provided with coupling arms (202) on both sides of one of its ends. These coupling arms (202) comprise at least two holes (203) or means of connection to other corresponding ones on the outer walls of the lateral elements (11). These arms will preferably hold the lateral walls by means of securing screws in all their holes. However, especially when used for cleaning sloping surfaces, the arms will be secured with a single screw on each side, allowing the floatation body to tilt (200) in respect of the drive and cleaning body (100), held by the coupling arms (202).
The floatation body comprises lateral impulsion turbines (204). In a preferential embodiment, the lateral impulsion turbines (204) are attached to the coupling arms (202), along with the first chamber (201). The activation of these turbines when the cleaner is in a state of weightlessness through the compensation of the weight with the corresponding floating force will enable a lateral displacement to a new cleaning position. The turbines for securing the cleaner body will return the cleaner to the surface of the wall so that the assembly has free travel in all degrees since it is provided with forward and reverse movements, rotation, gripping and withdrawing from the surface to be cleaned, and lateral displacement.
According to a preferential embodiment, the floatation body (200) also comprises a second chamber (205) with variable volume, provided with an interior inflatable membrane. Filling/emptying said second chamber (205) with air is done by means of a connection (206) to an external compressor. Depending on whether greater or lesser floatation of the cleaner is needed, the variable volume chamber will be totally empty, thus meaning that the effective weight of the cleaner will be the maximum or will be partly full, or totally full of air, and the effective weight will therefore be the minimum. The second chamber comprises at least one perforated wall, so that when the inner balloon inside this is filled (totally or partly) with air, the water that the volume of air displaces can be drained out. According to a particular embodiment, the first fixed volume chamber and the second variable volume chamber constitute a prismatic body to which the coupling arms ( ) are linked; the chamber with variable volume is preferably located in the portion furthest from said prismatic body.
Furthermore, insofar as the floatation body (200) will when cleaning walls always be located at the top of the drive and cleaning body (100), it has been designed for the floatation body (200) to be provided in the portion furthest from said drive and cleaning body (100) with a scraper (210). The scraper is formed of a soft strip (211), normally made of rubber, arranged on a holding part (212); in accordance with a preferential embodiment this support is made up of a tube with circular section made of a light material and filled with injected foam, thus minimizing its density and constituting a further floating part. In a preferred embodiment, the holding part is set on one or more supports joined to the floatation body (200) which allow the scraper to take up different angular positions, modifying the distance to the wall in the same way in accordance with operating requirements.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/ES2014/070448 | 5/30/2014 | WO | 00 |
