EP0190576B1

EP0190576B1 - Method and apparatus for spray-impregnating materials

Info

Publication number: EP0190576B1
Application number: EP8686100533A
Authority: EP
Inventors: Eric Corneel Mahieu
Original assignee: STAVELSE Metaalbouw pvba
Current assignee: STAVELSE Metaalbouw pvba
Priority date: 1985-01-21
Filing date: 1986-01-17
Publication date: 1989-09-20
Also published as: EP0190576A3; DE3665677D1; EP0190576A2

Description

Windows, doors, panels and other building elements out of wood or any other material must be treated, on the one side to protect them from the hurtful effects of liquid, worms, fungi and the like; on the other hand to give these elements a certain colour.
For that purpose, several techniques are available: submersion, injecting, impregnation, expulsion of the sap; techniques which protect the building elements by means of special treatment liquids. Submersion is a much applied technique, based on impregnation, which offers good results. However, the efficiency of the submersion technique is not very high: the necessary amount of liquid is very large, this large amount is subject to ageing processes because the product isn't undergoing enough renewal, a lot of space is needed when it concerns an automatic transit- system, the vaporization above the surface of the open submersion basin harms the quality of the treatment liquid, is hurtful for the health of people in the proximity of the basin and increases the fire- and explosion-risk.
A second technique based on impregnation is the one by which the building materials are placed into a closeable booth. Spread over the innerwalls of the booth, there are fixed nozzles which are directed inwardly. These known spraying apparatus are based on a method by which the elements are surrounded by a dense cloud of drops of the treatment liquid. In this way an effect similar to the effect obtained by submersion in a basin with treatment liquid, is obtained: not only the surfaces turned to the nozzles, but all surfaces and corners of the elements are steeped with the treatment liquid. Thus, the use of this closed boot is an economical alternative for the open submersion basins.
However, these machines with fixed nozzles still need a relative large stock of treatment liquid which is expensive and which is the object of ageing processes changing the characteristics of the solution. Also the maintenance of the nozzles by means of dissolving solvents is difficult, so that often only one type of treatment liquid can be used. Moreover, these booths are not suitable for the use of pigmentated products. The removal of resin from the nozzles isn't possible neither.
The method in accordance with the invention for treating building materials, all kinds of woodwork and other pieces out of wood or other materials by means of the impregnation technique carried out by alternating spraying a dense cloud of drops of the treatment liquid on the materials is characterized by intervals of spraying an excess of treatment liquid with intervals when no spraying takes place. By doing so, the treatment liquid gets time to impregnate in the elements, and the excess of treatment liquid gets time to run down from the surfaces. The treatment liquid which lands on the elements during the following spraying period, finds under itself fairly dry surfaces on which no layer of treatment liquid is to be detected,.so that the impregnation can act again. This method of successive impregnation waves, caused by surrounding discontinuously with a dense cloud of drops of the treatment liquid, results in a bigger impregnation depth of a better protection of the elements.
The method in accordance with the invention can be carried out by the current spraying devices with fixed nozzles spread over the innerwalls of the booth, by activating with intervals the pump or pumps which supply the nozzles with treatment liquid.
US-A-3001504 discloses a spraying apparatus comprising a closeable booth, nozzles for dispersing a treatment or coating liquid mounted on a frame which is moveable within the booth and a system of containers, compressors and supply-tubes for supplying the nozzles with a treatment or coating liquid.
These known devices do not remedy the problems of the maintenance of the nozzles and of the booth, nor do they remedy the restriction to only one type of treatment liquid and to colourless treatment liquids.
The spraying apparatus in accordance with the invention, based on the method in accordance with the invention, is intended to remedy the higher mentioned problems. The spraying apparatus in accordance with the invention allows to treat the elements with all existing treatment liquids, thus even those treatment liquids with volatile components with a low inflaming temperature or with pigments and resinous components. This means that the treatment liquid has a certain colour and gives this colour along with the materials. The improvements even allow to use several colours by turns with one spraying apparatus.
The spraying apparatus in accordance with the invention for treating building materials, all kinds of woodwork and other pieces out of wood or other materials by means of the impregnation technique by spraying an excess of the treatment liquid on the materials, consisting of a closeable booth a frame movable to and fro within the booth and carrying nozzles for dispersing the treatment liquid and a system of tanks, pumps, taps and conduits for supplying the nozzles is characterized in that the frame is provided with two series of nozzles each mounted on a separate supply-tube which are both mounted on the frame, of which the first series of nozzles are directed to the middle of the booth and which can be supplied with treatment liquuid or a solvent; and of which the second series of nozzles are directed to the outerwalls of the booth and which can be supplied with a solvent.
Furthermore, the spraying apparatus in accordance with a further embodiment of the invention is characterized by the connection conduits which link up the different tanks, comprising solvent and treatment liquid, mutually and which allow the liquid to be transferred in a specific direction.
As an example, without any restricting character, a detailed description of a possible embodiment of an apparatus in accordance with the invention for applying the method in accordance with the invention follows hereafter. This description refers to the accompanying drawings, in which:

Fig. 1 is a schematic representation of a possible implantation of the spraying apparatus in accordance with the invention.
Fig. 2 is a vertical cross-section of the spraying booth of the spraying apparatus in accordance with the invention.
Fig. 3 is a schematic top-view of the whole of tanks, pumps and conduits of the spraying apparatus in accordance with the invention.
Fig. 4 is a perspective view on a possible embodiment of the drive of the frame of the spraying apparatus in accordance with the invention.

Booth (1) (Fig. 1), made of resistant material, is provided on its both sides with a door (4), this allows the elements, to be treated, to be brought in n on one side of the booth (1), and the treated elements to be taken out on the other side. The described case of the booth (1) has the shape of a rectangular parallelepiped. It is also possible to provide the booth (1) with only one door (4).
Next to the booth (1), the system (2) of tanks, pumps, conduits and steering valves is set up. Further, a steering panel (3) is provided.
As represented on Fig. 2, a frame (5) is provided within the booth (1), frame (5) which is hung up to a waggon (6) which is hung up on four wheels (7). These wheels (7) rest two by two on profiles (8), fixed on the walls over the length of the booth (1) (also Fig. 4). Along these profiles (8), runs an endless chain (9), which is set into.motion by an electromotor (10), placed outside the booth (1), by way of a transmission belt (11).
The frame (5) forms within the booth (1) an inscribed rectangle. On the frame (5), a tube (14) is provided, which supplies the nozzles (13), which are directed inwardly. Furthermore, a second tube (49) is provided on the frame (5), which supplies the second series of nozzles (65) which are directed to the outerwalls and to the chain (9).
Spraying the treatment liquid by means of nozzles mounted on a frame moving to and fro, results in two problems. On the one side there's the problem of driving the frame, on the other hand there's the problem of supplying the nozzles with treatment liquid or solvent.
As certain components of the treatment liquid, a.o. the solvent which dilutes the treatment liquid, are volatile and have a low inflaming temperature, it is absolutely necessary to close the booth (1) during, and to provide the booth (1) with fresh air after spraying, and to keep all electric parts out of the booth (1). This to avoid that a possible spark should make explode the gas mixture within the booth (1). These requirements bring along certain problems concerning the drive. Chains (9) (Fig. 4), which transmit the movement of the electromotor (10) to the frame (5), cannot move to and fro as this implies the provision of switches within the booth (1) to reverse the movement of the electromotor (10) at the end of each movement-direction of the frame (5). This continuous movement of the chains (9) must be reversed into a movement to and fro of the frame (5) by means of a transmission. For this purpose, a connection-hook (52) is mounted on both sides of one or more links of the chains (9). On these connection-hooks (52) a carrierbar (53) is mounted, on which sits a roller (54). This roller (54) is found between the four sides of the frame (55), mounted on frame (5). This frame (55) allows the roller (54) to pass over the difference in height between the upper side (56) and the lower side (57) of the chain (9). This roller (54) takes along the frame (55), and thus the frame (5), during its movement to and fro on the chain (9). Such a chain (9) is provided on both sides of the booth (1), so that the carrierbar (53) connects both chains (9) and on both sides of the frame (5) a frame (55), in which a roller (54) is found, is mounted, so that the frame (5) is pulled forward symmetrically by means of both frames (55). Possibly only one frame (55) can be provided in the middle of the frame (5). It suffices then to place one chain (9) in the middle, against the ceiling of booth (1).
The chain (9) runs around chain-wheels (58). On the spindle of chain-wheel (58), a second chain-wheel (59), driven by a chain (60) out of the main spindle (61) with chain-wheel (62), is mounted. The main spindle (61) runs through the wall of the booth (1) and is driven on his turn by means of a transmission belt (11) out of the electromotor (10), placed outside the booth (1). Fig. 4 further shows the profiles (8) on which the wheels (7) of the small waggon (6) run.
The problem of supplying the nozzles, is solved by means of two or more hoses (17 and 50) (Fig. 2) which are windable on two or more auto-rewinding hose reels (resp. 16 and 51). Such an auto- rewinding hose reel (16 and 51) consist of a fixed axial tube (resp 15 and 66) functionning as a spindle around which the hose reel (res. 16 and 51) rotates; and of a springsystem, worked in within the hose reel (16 and 51), which makes the hose (resp. 17 and 50)-being rewinded automatically when the distance between the extremity of the hose (17 or 50) and the hose reel (16 or 51) becomes smaller. The extremity of the hose (17 or 50) acts respectively as the discharge or the supply. These hose reels (16 or 51) can be mounted on the frame (5) or the waggon (6). The axial pipes (resp. 15 and 66) act then as the discharge of the hoses (resp. 17 and 50) and thus supply to the tubes (14 and 49) on the frame. The extremities of the hoses (resp. 17 and 50) actthen asthe supply or receive solvent or treatment liquid from the pumps. The hose reels (16 and 51) can also be mounted in the booth (1), as represented on Figure 2 where both hose reels (16 and 51) are worked into the ceiling of the booth (1), the axial tubes (resp. 15 and 66) actthen as supply, the extremities of the hoses (resp. 17 and 50) are then the discharge or supply to the tubes (14 and 49) on the frame (5).
The springsystem in the hose reels (16 and 51) allows the hoses to be unrolled when the frame (5) moves away from the hose reels (16 and 51). The springtension is in such a way that both hoses (resp. 17 and 50) are rewound on the hose reels (rssp. 16 and 51) under the reverse movement. This system prevents the hoses (17 and 50) to fling about within the booth (1).
The first hose (17) is connected only with the first tube (14) with the nozzles (13) which are directed inwardly. This first hose (17) supplies only treatment liquid. The second hose (50) is connected with both tubes (14 and 49) and supplies only solvent. Both hoses (17 and 50) are connected with their respective tubes (14 and 49) by means of repercussion-valves (68).
At the bottom of the booth (1), a gutter (29), sloping towards the middle of the booth (1) breathwise and towards the drainconduit (30) lengthwise, is provided. A grating (12) is placed above the gutter (29), which allows the to be treated elements to be placed in the booth (1) or to be driven in or out the booth (1) before and after the treatment, hung up on one or more special carts.
The booth (1) is further provided with one or more ventilators (28) which draw off the developed vapours and blow in fresh air when the treatment or cleaning process is finished. The ventilators (28) are activated each time one of the doors (4) is opened, for safety reasons.
The system (2) (Fig. 1) of tanks, pumps and conduits (Fig. 3), which supplies to the axial tubes (15 and 66) (Fig. 2), consists substantially of at least one tank (21) for the treatment liquid, a tank (22) for polluted solvent and a tank (23) for clean solvent; of a pump (24) for the treatment liquid and a pump (25) for the solvent, polluted or clean; and of a number of connection conduits and a number of steering valves. The term polluted solvent indicates that solvent which is already mixed with an amount of treatment liquid, as it has already served several times for cleaning the booth, the nozzles and the conduits which are in common for solvent and treatment liquid. The term clean solvent indicates that solvent which isn't mixed with treatment liquid.
As represented on Figure 3, a connection conduit (31) links both tanks (22 and 23) with a first steering valve (32) which is linked with a second steering valve (34) via connection conduit (33), which leads the liquid through pump (25). Steering valve (34) supplies in one position to the axial tube (66) Fig. 2) via conduit (41) and in the other position to a third steering valve (35) via a connection conducit (36). Steering valve (35) supplies in one position to tank (22) via a connection conduit (37) and in the other position to tank (21) via a connection conduit (38). The possible flow- directions in these connection conduits (31, 33, 36, 37, 38) and conduit (41) are indicated with an arrow. Conduit (41) leads successively through a manometer; a tap, a filter, a tap and a manometer; indicated on Figure 3 with number 39. The connection conduit (63) links tank (21) via pump (24) with a steering valve (42) which supplies in one position back to tank (21) via connection conduit (64) and in the other position to conduit (44) connected with axial tube (15) Fig. 2). Conduit (44) leads successively through a manometer, a tap, a filter, a tap and a manometer; indicated on Figure 3 under number 40. On the other side of the tanks (21, 22 and 23) a drainage conduit (30) (Fig. 2) arrives at a steering valve (43) which supplies in one position to tank (21) via connection conduit (69) and in the other position to steering valve (45) via connection conduit (46). Steering valve (45) supplies to tank (22) via connection conduit (47) or to tank (23) via connection conduit (48), dependent on her position. In order to facilitate the rest of the description, the position of a steering valve (32, 34, 35, 42, 43, 45) drawn in full line on Figure 3 will be indicated with position A, the position in dashline with position B.
This arrangement of the tanks, pumps, steering valves and connection conduits allows the following possibilities. On the one side: supply of treatment liquid to the nozzles (13) via conduit (44), axial tube (15) and hose (17) by means of pump (24) if steering valve (42) is set in position B. The surplus of liquid, which flows of the walls of booth (1) and off the treated elements, returns via gutter (29) and drain conduit (30) (Fig. 2) to tank (21), if steering valve (43) is set in position B. With steering valve (42) in position A, the treatment liquid is pumped about via connection conduits (63 and 64), what allows the treatment liquid to be mingled. This can be necessary when the treatment liquid must be diluted or when certain components of the treatment liquid are settled down, e.g. after a period during which the spraying apparatus hasn't been used.
On the other hand: supply of solvent to the nozzles (13 and 65) via conduit (41), axial tube (66) and hose (50). This is important to prevent the treatment liquid; consisting of a pigmentated oillike solution, which contains thus resins; from stopping up the nozzles (13) or tube (14) or from forming a layer on the walls of the booth (1) or on the chains (9) when the spraying apparatus is inactive during a certain time. After the termination of production period, first polluted solvent is pumped out of tank (22) through nozzles (13 and 65), with steering valve (32) in position B and steering valve (34) in position A by means of pump (25) and via conduit (41). The polluted solvent dilutes the major part of the remaining treatment liquid in booth (1), and returns via drain conduit (30), via steering valve (43) in position A and steering valve (45) in position B to its own tank (22). After that, the same is done with clean solvent with steering valves (32, 34, 43 and 45) all in position A. When the level in one of the tanks (21, 22, 23) becomes too low, the connection conduits allow the solvent to be transferred. When the level of the treatment liquid becomes too low, treatment liquid under concentrated form must be added and this concentrated liquid must be diluted with polluted solvent. By means of pump (25) and steering valves (32 and 34) in position B and steering valve (35) in position A, the polluted solvent is pumped from tank (22) to tank (21). After this, everything needs to be well mingled in tank (21), this is possible with connection conduits (63 and 64) and steering valve (42) in position A. When the level of the polluted solvent becomes too low, tank (22) can be replenished with clean solvent by means of pump (25) and steering valve (32) in position A and steering valves (34 and 35) in position B.
The levels of tanks (21, 22 or 23) can be read visually, by means of a float or a gauge glass, or can be continuously registrated by electrical means. The steering valves can be hand operated or operated full automatically by steering panel (3). This steering panel (3) steers, on the basis of the chosen program: treatment of elements or cleaning the booth (1) or other procedures, the steering valves, pumps (24 and 25), the electromotor (10) and ventilator (28). The program for treating the elements can for example consist of:

1th: Spraying: pump (24) and electromotor (10) work.
2th: Pause? the treatment liquid gets the time to impregnate in the wood, the excess flows down of the walls and elements and returns to tank (21).
3th: Ventilation: sucking up the developed vapours and furthering the drying by means of ventilator (28).

The duration of each part of this program can be programmed in advance on steering panel (3) which watches the levels in tanks (21, 22 and 23). The program continuously controls if the steering valves are in the right position, so that the liquid returning from the booth (1) always returns to its own tank (21, 22 or 23). This protection is imperative to avoid that the treatment liquid should be made useless by adding wrongly an excess of solvent.
It's obvious, more than two tanks (22,23) can be provided for the solvent to divide it in more than two grades of pollution. By adjusting the number of pumps, steering valves and connection conduits, the solvent can be transferred to a tank of higher pollution.
To enable the use of two or more treatment liquids with a different colour, two or more tanks (21) must be provided and for each treatment liquid a separate hose reel (16), with a hose (17), which supplies to tube (14), via a repercusion valve (68), a separate pump (24), steering valve (42), connection conduits (63 and 64) and conduit (44), with a system (40) of taps, filters and manometers, must be provided. In this way the supply of the different treatment liquids is separated completely, except for the tube (14) and the nozzles (13). However, these can be cleaned with solvent, thus mixture of the colours is prevented. The frame (5) can possibly be provided with a separate tube (14) with nozzles (13) for each colour, in order to separate the different colours completely. The treatment liquid which stands still between a pump (24) and a repercussion valve (68) in a conduit (44) and a hose (17) cannot harden as everything is airtight.
The spraying apparatus in accordance with the invention with the frame (5) movable to and fro and the continuous spraying nozzles (13) combines the advantages of method in accordance with the invention, viz. surrounding the elements discontinuously with a dense cloud of treatment liquid drops, with the advantages which the limited number of nozzles (13) for the treatment liquid entails.
Due to the second series of nozzles (65) and the supply of solvent via hose (50) to both tubes (14 and 49) or to both series of nozzles (13 and 65), the booth (1) is perfectly cleanable inside. Solvent and treatment liquid are supplied totally separated, except for the tube (14) and nozzles (13). The connection conduits which link up the tanks (21, 22 and 23) mutually, allow an economical use of the solvent. The possibility to bring the elements in or out of the booth (1) by means of carts or racks, allows to use these carts or racks as stockage before or after the treatment and for the further finishing. Endless stacking up and unloading and the labour involved in doing so, is avoided in this way.

Claims

1. Method for treating building materials, all kinds of woodwork and other pieces out of wood or other materials by means of the impregnation technique carried out by spraying a dense cloud of drops of the treatment liquid on the materials, characterized by alternating intervals of spraying an excess of treatment liquid with intervals when no spraying takes place.

2. Spraying apparatus for treating building materials, all kinds of woodwork and other pieces out of wood or other materials by means of the impregnation technique by spraying an excess of the treatment liquid on the materials, consisting of a closeable booth (1) a frame (5) movable to and fro within the booth (1) and carrying nozzles (13 and 65) for dispersing the treatment liquid and a system (2) of tanks, pumps, taps and conduits for supplying the nozzles (13 and 65) characterized in that the frame (5) is provided with two series of nozzles (13 and 65) each mounted on a separate supply-tube (resp. 14 and 49) which are both mounted on frame (5), of which the first series of nozzles (13) are directed to the middle of booth (1) and which can be supplied with treatment liquid or a solvent; and of which the second series of nozzles (65) are directed to the outerwalls of booth (1) and which can be supplied with a solvent.

3. Spraying apparatus according to claim 2 wherein the system (2) of tanks consists out of one or more tanks (21, 22, 23) for each treatment liquid with a different colour and of two or more tanks for solvents with different grades of purity; characterized by the connection conduits which link up the different tanks in such a way, via one or more pumps, that it is possible to transfer solvent with a certain grade of purity to a tank comprising solvent with a lower grade of purity or to a tank comprising treatment liquid as desired.

4. Spraying apparatus according to claim 3, the bottom of the closeable booth (1) being provided with a gutter (29) sloping towards one or more drain conduits (30) characterized in that the drain conduits (30) leadtothetanks (21,22,23) through a system of steering valves (43, 45) allowing to select one or more of the tanks (21, 22, 23) into which the drain conduits (30) discharge.

5. Spraying apparatus according to claim 2 wherein each supply-tube (14 and 49) is supplied by means of a hose (17 or 50) on a hose reel (resp. 16 and 51) which is provided with a springsystem in such a manner that the hose (resp. 17 and 50) can unroll freely and is rewinded when the distance between both extremities of the hose becomes smaller due to the movement of the frame (5) which carries nozzles (13 and 65).

6. Spraying apparatus according to claim 5 wherein the first hose (17) is connected with tube (14) and with pump (24) forthe supply of treatment liquid.

7. Spraying apparatus according to claim 5 wherein the second hose (50) is connected with both tubes (14 and 49) and with pump (25) for the supply of a solvent.

8. Spraying apparatus according to claim 5 wherein for each treatment liquid with its own colour, a hose (17) is provided, which is connected with one of the tanks comprising treatment liquid via a pump and which supplies to tube (14) with nozzles (13) on the movable frame (5).

9. Spraying apparatus according to claim 5 wherein the hoses (17 and 50) are connected with tubes (14 and 49) by means of a repercussion valve (68).

10. Spraying apparatus according to one of claims 2 to 9 wherein the position of the steering valves, the levels of the tanks, the electromotor (10), pumps and ventilator (28) are steered and controlled automatically.