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(11) | EP 1 563 918 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method and machine for cleaning large bolts |
| (57) Method and Machine for cleaning large bolts. Machine for cleaning large bolts consisting of a support containing the cleaning means. It has a cover which covers the operation, preventing any contaminating items from getting out. The bolt is received vertically, tilted until it reaches a horizontal position in which the cleaning is done and then passed on vertically again. It has a shaft and drive means for altering the vertical position to horizontal and vice-versa. The cleaning operation is done by moving brushes and turning the bolt horizontally. The brushes follow a cam set close to the bolt position. It also includes a working method which consists of reception in the vertical position, tilting, verification and placing back in the vertical position for delivering the clean bolt. This is for application in cleaning large bolts, especially the sort used for securing nuclear power station reactors. |
[0001] The technical field involved in this invention is specifically that of cleaning the bolts used for securing nuclear power station reactors as well as other large bolts.
[0002] Heavy industry as a whole, and as an example we refer not exclusively to nuclear power stations, requires maintenance operations, which are carried out by technical staff when reloading fuel, and before and after, when the components of the station are dismantled and set up.
[0003] The items forming part of the reactor, the core of the nuclear power station, require painstaking maintenance.
[0004] Such is the case of the bolts that secure the reactor cover, which have to perform their function efficiently for safety reasons, and to maintain safety they have to be kept in perfect condition after each reactor-dismantling operation for recharging fuel. These bolts can be several metres in length and have very considerable diameters, weighing several hundred kilograms.
[0005] One particular circumstance involved here is that the nuclear power station zone tends to be radioactively contaminated, and it proves necessary to ensure that the bolt cleaning operation has sufficient safety conditions both for keeping the product in perfect condition, on economic grounds on one hand, and for security on the other.
[0006] Statement of the previous state of the art. It is indeed a fact that the bolts have been cleaned up to now, but cleaning as it has been done before nevertheless proves inconvenient, difficult and risky to a certain extent.
[0007] As an antecedent, the machine for mechanically cleaning bolts made by South Texas Project STP is known, consisling of a boit-cleaning machine formed of a vertical body which, apart from holding the bolt, must turn this to clean it. Inspection of the cleaning processes is done by means of a stair, normally a ladder, which makes it difficult to monitor the cleaning work. The vertical position of the bolt makes it difficult to turn, given its large support length on the machine, which makes the effectiveness of this rotation much more difficult.
[0008] This invention covers a method and machine for cleaning large bolts, which has a specific layout facilitating the work for loading and unloading the bolt, carrying out the horizontal cleaning function, which manages to enhance both the bolt treatment conditions, as it rests on a large surface area, all of which drives the rotation movement, making the turning operation possible and effective during the cleaning process and also has the advantage of running in a slightly depressed atmosphere, as it has an absorption system and a replacement valve for dirty air, which furthers the cleaning and decontamination of the part.
[0009] In order to make the following explanation clearer five sheets of drawings are adjoined, showing the essence of this invention in six figures.
[0016] In these figures 1 represents the frame, 2 the legs, 3 the wheels, not essential but useful, 4 a front space in the frame, 5 the box, 6 the motor, 7 the cover, 8 the bearing box, 9 the bearing box, 10 the roller support bar, 11 the bolt rotation roller, 12 the bolt rotation roller, 13 the work brush guard, 14 the work brush, 15 the work brush motor, 16 the cam, 17 the window, 18 the guide bar, 19 the coupling belt between the cleaning assembly guided by the bar 18, 20 the gear transmission box, 21 the transmission belt or chain, 23 a pulling roller, 24, a pulling roller, 25 a pulling roller, 26 the cover hinging pin, 27 the motor, 28 coupling hinging between the shaft and the box, 29 the hydraulic piston, 30 the turning axis of the box on the frame, 31 the shaft for hydraulic piston action, 32 the rear part of the frame opposite the shaft 30 side, 33 the securing of the hydraulic piston, 34 crosspiece of the frame for supporting the hydraulic piston, 35 hole for the hydraulic pistons 29 through the frame crosspiece 34, 36 hydraulic pistons, 37 the coupling frame between the supports of the shafts 28, 38 shaft damper 28, 39 check valve, 40 a mobile wall, 41 a spring, 42 box outlet hole 5, 43 the conduit tube from the outlet 42, 44 the exhauster, 45 the filter.
[0017] As stated above, the machine consists of an assembly whose box 5 is able to house a bolt, being fitted with a cam profile 16 whose shape coincides with said bolt.
[0018] The brush unit 14 runs along the bar 18, which is the guide for movement of the runner 19 which holds the brush and the corresponding guard, moving this along the bolt, and which is pulled along by the chain or belt 22 and driven by the motor 6.
[0019] The cleaning operations are monitored directly as they are carried out horizontally. The frame 1 has a working platform suitable for facilitating visual access to this part of the machine's work.
[0020] The machine receives the bolt vertically as this is hung from the crane which withdraws this, and receives it backing it onto the rollers 11 and 12 as both the hydraulics 29 and 36 make the box hinge 5 around the shaft 30 until it gets into the horizontal position.
[0021] The box rotation is approximately 85°, since this means that the bolt is balanced towards the box, with no danger of falling.
[0022] The hydraulic system which moves the box 5 can also consist of another type of parts, such as spindles or pneumatic means without these mechanical or pneumatic embodiments, though not totally rejected, being preferred over the hydraulic system.
[0023] The resulting operating method stems from the activity of the cleaning assembly itself, which scrapes the bolt getting into the inside part of the thread by means of the brush 14 bristles. At the same time the bolt turns by its support on the rollers 11 and 12 by means of the motor 27 rotating. At the same time the air inside the box is sucked out. This is led to the outlet hole 42 through a tube 43 towards an exhauster 44 fitted with a suitable filter 45.
1. Machine for cleaning large bolts, of the type that holds each bolt unit as this proceeds
to its rotation and brushing, characterised by consisting of: a frame (1) which holds: a cleaning box (5) able to house the bolt;
means for tilting the box (28-31) from the bolt reception position to the working
position and vice-versa; bolt rotation means; cleaning means.
2. Machine according to claim 1, characterised in that the frame (1) consists of a base with a sturdy structure which in one part (4) forms
a space housing part of the cleaning box in the transit of the box from the vertical
and the horizontal planes, able to counterweight the vertical position of the box
(5) carrying a bolt.
3. Machine, according to claim 1, characterised in that the cleaning box (5) consists of the box itself which contains rollers (11, 12) for
supporting the bolt, and one or more motors, for air inlet (39-41) and outlet (42,
43) and a closing cover (7).
4. Machine, according to any of claims 1 or 3, characterised in that the cleaning box (5) has in one of its sides a cam profile (16) coinciding with the
form of the bolt so that the cleaning device (14) resting (32) on said cam (16) keeps
at a uniform distance with relation to said bolt.
5. Machine, according to any of claims 1, 3 or 4, characterised in that the rollers (11, 12) of the cleaning box rotate by the action of at least one motor,
and determine by this rotation the rotation of the bolt resting on these.
6. Machine, according to claim 1 and any of claims 1 to 5, characterised in that the cover (7) is fitted with windows (17) or means for viewing the internal cleaning
process.
7. Machine according to claim 1 and any of claims 1 to 6, characterised because the air inlet to the box (5) is fitted with a check valve (39-41).
8. Machine, according to claim 1, characterised in that the air outlet (42) of the box (5) is fitted with a coupling to a hose (43) and this
to an exhauster (44) fitted with a filter (45).
9. Machine, according to claim 1, characterised in that the cleaning box (5) is fitted with a tilting device by means of hydraulic pistons
(29-36).
10. Machine according to claim 1, characterised in that it has a work supervision platform connected to the frame.
11. Method for cleaning bolts which, by means of the machine as described in claims 1
to 10, consists of a bolt reception and delivery system with the cleaning box in a
position close to the vertical with a preferential inclination of 5° in respect of
said vertical, after which the box is tilted to the horizontal plane. In this position
the cleaning means are activated under the operator's supervision through the monitoring
windows at the same time as the inside air is sucked out and replaced with fresh air,
simultaneously with the air drawn out being properly filtered, as the cleaning operation
is performed by brushes which act along the bolt which is rotated during the operation,
these brushes being moved along the bolt following a cam profile corresponding to
the shape of said bolt.