Apparatus for the treatment of parts by successive immersions in at least two baths

Abstract

Apparatus for successively immersing articles in different baths, as in galvanoplasty or in cleaning parts by using a series of cleaning solutions. A treatment vessel is provided in which to immerse the parts first in one bath, then in another. The various baths are supplied to the treatment vessel through independent siphon conduits, each connected to one of a plurality of bath reservoirs located below the vessel so that when it is desired to empty the vessel, the bath liquid can be siphoned back to the reservoir from which it came through the same siphon conduit by which it was furnished the treatment vessel in the first place. In order to avoid the use of pumps, the baths are transferred from each of the reservoirs by individually pressurizing each reservoir, thereby forcing the bath up through its siphon conduit into the treatment vessel. By using siphons in this manner, accidental intermixing of the bath solutions is prevented.

Description

BACKGROUND OF THE INVENTION

The present invention relates to apparatus for treating parts by successive immersions in at least two baths.

Although not limited in application to the field of galvanoplasty, the present invention is applied principally to that technique. Another important application is in the cleaning of parts, for example.

For the treatment of parts by means of various baths, the most common practice requires the immersion of the parts into a first treatment vessel, to take them out, then to immerse them, with or without intermediate immersion into a liquid for rinsing, into the next bath held in another treatment vessel, and so on.

The displacement of the parts from one bath to the next one necessitates relatively complicated installations. Furthermore, the treatment vessels cannot be closed, resulting in a loss in bath material by evaporation, and requiring, that the treatment be carried out under aspiration hoods, in order to avoid injurious emanations. Furthermore, the treatment lines are most cumbersome, particularly since it is necessary to provide vessels for rinsing operations between the various treatment vessels.

It has been attempted heretofore to remedy these inconveniences by using only one treatment vessel which holds the parts throughout the treatment, and by successively introducing the various baths into that treatment vessel with or without intermediate introduction of rinsing liquid. However, in the installations known to operate in that manner, filling and emptying the treatment vessels are obtained by means of pumps and electrical valves or others, making the installations complicated to build and maintain, and consequently costly both to manufacture and to use, as well as being subject to breakdowns and to risks of contamination of the baths, one by the other, and to errors of manipulation leading to inter-mixing of the baths.

The purpose of the present invention is to provide a treating apparatus that operates on the principle of bringing baths successively to only one treatment vessel, but without the inconveniences of the installations previously described.

SUMMARY OF THE INVENTION

The invention resides basically in successively filling a treatment tank or vessel with different baths through individual siphon conduits each connected to one of a plurality of reservoirs that are located below the level of the treatment vessel. When it is desired to fill the treatment vessel with a bath from one of the reservoirs, the reservoir in question is pressurized, thereby forcing the bath liquid up through its siphon conduit into the treatment vessel. In order to empty the treatment vessel, the one reservoir is depressurized, permitting the bath to siphon back through the same siphon conduit by which it was supplied to the treatment vessel. A second bath may then be introduced into the treatment tank by pressurizing another reservoir in the same manner.

The bath in the treatment vessel can not flow to any of the other bath reservoirs due to the fact that only the siphon conduit for the bath in use is primed. Consequently the bath can drain only to the reservoir from which it came. Furthermore, since each of the reservoirs is a closed container, filling of the treatment tank from one of the reservoirs creates a counter-pressure in the other reservoirs which prevents the bath from rising in their respective siphon conduits even when the level of the bath in the tank rises above the elbows of the siphons. The treatment tank can also be rinsed between baths by introducing a rinsing liquid through a rinsing siphon conduit which also functions to drain the tank.

Pressurization of each reservoir is desirably achieved by means of an expansible bladder trapped within each of the sealed reservoirs but connected to a suitable source of air pressure outside the tank.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The drawing shows, by way of example, one embodiment of the object of the invention.

FIG. 1 is a perspective view of an installation of galvanoplasty;

FIG. 2 is a top view on an enlarged scale of a detail of the installation shown in FIG. 1;

FIG. 3 is a schematic front view of a part of the installation shown in FIGS. 1 and 2; and

FIG. 4 is a sectional view generally along line IV--IV of FIG. 3.

The installation represented comprises a frame holding a table 1 surrounded by a sheet metal protecting cover 2 to house some of the organs and appliances of the installation. Table 1 carries a panel board 3 for the electronic control of its various functions and a cylindrical treatment vessel or tank 4 traversed by a rod 5 that extends axially at its lower end through the sloping bottom 4a of tank 4 and is connected to a vibrator 6 intended to give it an oscillating and vibrating rotative motion. This rod 5 carries four baskets 7 intended to contain the parts in treatment. The bottom of these baskets are fitted with one or several helicoidal ramps so that the parts move along those ramps on account of the vibrating motion of the basket and turn over while hitting obstacles designated to this purpose and, as they reach the upper extremity of the ramp, fall to a lower zone to create a smooth and efficient stirring, thus permitting galvanic treatment of the entire surface of the parts. The ramps of baskets 7 are connected to the cathode, and are made of metal, but are preferably partly plastified.

Situated under table 1, that is to say below the level of treatment vessel 4, are eight reservoirs 8, two of which only are represented in FIGS. 3 and 4. These reservoirs, whose capacities vary from three to five times that of vessel 4, are intended to contain the baths into which the parts to be treated are successively immersed. Each of reservoirs 8 is a hermetically sealed container fitted with a filling plug.

Each reservoir 8 is connected to the treatment vessel 4 by a siphoid conduit 9. At the vessel, the six conduits 9 come to a sort of lateral trough 4b, projecting from the side of the tank at the lowest point of its bottom which is sloped as illustrated in FIG. 4. The lower extremity of each siphoid conduit separates into two branches. One of the branches 9a is fitted with a check valve 10 to enable the liquid to flow in the direction of the arrow 11, that is to say in the direction of the reservoir, whereas the other branch 9b is fitted with a check valve 12 to enable the liquid to flow in the direction of the arrow 13, that is to say in the direction of the treatment vessel 4. Branch 9b is surrounded by a filter 14 intended to filter the bath of reservoir 8.

Furthermore, each reservoir 8 is connected to the vessel by a capillary siphoid tube 15, located under the corresponding siphoid conduit 9, one of them being visible on FIG. 4. Each of the capillary tubes enters the trough 4b of the treatment vessel 4 as shown on FIG. 4, and has its mouth at this end disposed as near as possible to the lowest point in the bottom of the vessel in order to thoroughly empty it of its contents.

Each reservoir 8 includes an expansible air chamber or bladder 16, with non-rigid and flexible walls. Bladders 16, which can be inflated from outside the reservoir itself, are intended to produce an overpressure inside of the reservoirs 8 by filling the chambers with a gas under pressure, air in this case, without contact between this air and the baths contained in the reservoirs.

The installation comprises also a siphoid rinsing conduit 17 which is extended by a double elbow 17a and 17b for connection to the drain 18. A retention column is thus created in 17c, that is to say between elbows 17a and 17b. The rinsing liquid, water in this case, is sent under pressure through a conduit 19 of lesser cross-section than that of rinsing conduit 17. Conduit 19 penetrates into conduit 17 in the upper part of elbow 17b and extends to part 17c to make an arrangement similar to a venturi. A capillary siphoid tube 20 coming into the rinsing conduit 17 on the one hand and into the treatment vessel 4 on the other hand, in the vicinity of its lower point, permits thorough emptying of the treatment vessel from its rinsing liquid.

The installation as described and represented operates as follows:

Air under pressure is sent to the air chamber 16 of one of the reservoirs 8 whose bath one desires to use firstly. Since the volume of that air chamber increases it creates an overpressure within the reservoir 8 which forces the bath contained in that reservoir to penetrate into branch 9b of siphoid conduit 9 after filtration through 14. The bath is thus pushed into vessel 4 through siphoid 9 with non contamination from the pressurizing air, thanks to chamber 16. While entering treatment vessel 4, the bath is kept from penetrating other reservoirs 8 by the fact that, since each reservoir is completely enclosed and air tight a counterpressure exists inside of siphoid conduits 9 leading to the other reservoirs, preventing the bath from rising in the elbows of the other siphoid conduits. On the other hand, the bath in the treatment vessel 4 can not enter the rinsing conduit 17, due to the retention column existing in 17c and due to the fact that elbow 17d of its siphoid is situated higher than the elbows of conduits 9.

When the bath has reached the desired level in the treatment vessel 4, the flow of air into the air chamber 16 is interrupted, but the pressure is maintained in order to hold the bath in vessel 4. It must be noted that if, by accident, an exaggerated amount of bath is sent to the treatment vessel 4, the surplus is evacuated by an overflow tube 21 fitted inside the said vessel. The main purpose of the overflow tube 21 is, however, to permit the evacuation of occasional foam that might float on the rinsing water and also the evacuation and the return of air in the treatment vessel, during its filling and emptying operations.

The emptying of the treatment vessel 4 is obtained by releasing the pressure in the air chamber 16. This creates a siphon effect which draws the bath in vessel 4 into reservoir 8 where it came from originally. The cross-section of siphoid conduit 9 is large enough to obtain a rapid return. When the liquid in vessel 4 reaches the level of the mouth of siphoid conduit 9 the siphon is de-primed and it drops a small amount of liquid into vessel 4. However thorough emptying of that vessel, to the last drop of the liquid it has held, is obtained by means of siphoid tube 15 which, being capillary, does not reject the rest of its contents when it becomes de-primed.

The rinsing of the treatment vessel 4 is obtained by sending water under pressure at 19 to enter vessel 4 through siphoid rinsing conduit 17. Owing to the fact that the connection between the adduction conduit 19 for emptying water and the siphoid conduit 17 is arranged like a venturi, priming of the emptying siphon occurs when the rinsing water level in vessel 4 reaches the level of the top of elbow 17d of conduit 17. The vessel 4 will then empty itself of all its rinsing water without the necessity of interrupting the supply of rinsing water from the supply conduit 19. When vessel 4 is empty it fills itself again and in that manner several successive rinsings can be automatically obtained until the admission of water at 19 is interrupted. When the siphon of conduit 17 is de-primed thorough emptying of the treatment vessel 4 of its rinsing water is obtained by means of capillary siphoid tube 20.

In this manner the present installation operates without valves and without pumps, with the exception of the means to produce air under pressure for chambers 16 and rinsing water in conduit 19. It offers a very high operating security and requires practically no maintenance. Furthermore its cost of fabrication is low on account of its great simplicity.

Each reservoir 8 is fitted, at its lower part, with an emptying valve 22. The emptying of a reservoir 8 is obtained by opening its plug to let the air in, then by opening its tap 22. The rinsing of a reservoir 8 is obtained by removing the plug of the reservoir in question, and by sending rinsing water into vessel 4 through rinsing conduit 17. Since no counter-pressure occurs in the reservoir water can freely enter it. Should one desire to fill a reservoir 8 with a new bath through the treatment vessel 4 care must be taken to leave open only the plug of the reservoir in question, otherwise the new bath could enter into the other reservoirs whose plugs had been accidentally left open.

The installation is a compact unit which can be made in any size, from a table model for laboratories or for the treatment of very small parts to a large model for galvanoplasty plants of large production.

The chassis, the vessels, reservoirs and baskets are made of plastic material, for exemple polyvinyl, whose transparency allows observation of parts in treatment.

The baths are used in closed circuit and since vessel 4 is fitted with a lid 23 there is no emanation and consequently there is no need to operate under aspiration chapels.

It is to note that, in order to avoid the necessity of changing the anode between two plating operations with two successive baths, which would be practically impossible, it is necessary to work with only one anode that is unsoluble in the baths in use.

Claims

What I claim is:

1. Apparatus for successively immersing parts in at least two baths comprising

a treatment vessel in which the parts are immersed,

a plurality of separate bath reservoirs disposed below said vessel such that a bath in said vessel can flow by gravity into said reservoirs,

a plurality of siphon conduits each connecting one of said reservoirs with said vessel for siphoning a bath in said vessel to said one reservoir, and

means for pressurizing each of said reservoirs in order to force the bath therein into said vessel through the corresponding one of said siphon conduits.

2. Apparatus as defined in claim 1, which further includes a plurality of capillary siphon tubes corresponding in number to said reservoirs, each said capillary siphon tube connecting one of said reservoirs with said treatment vessel, the mouth of each of said capillary siphon tubes at said treatment vessel being disposed as near as possible to the lowest point in said treatment vessel in order to thoroughly empty it of its contents.

3. Apparatus as defined in claim 1, wherein each of said siphon tubes terminates at said reservoir in a pair of branches, one of said branches being fitted with a check valve permitting the flow of the bath into said reservoir, and the other of said branches being fitted with a check valve permitting the flow of the bath into said treatment vessel, the mouth of said other branch being surrounded by a filter for filtration of the bath leaving the reservoir in the direction of the treatment vessel.

4. Apparatus as defined in claim 1, which further includes a siphon rinsing conduit that enters said treatment vessel both for supplying rinsing liquid thereto and for evacuating said rinsing liquid from said treatment vessel.

5. Apparatus as defined in claim 4, wherein said siphon rinsing conduit is connected to a drain and is provided with a pair of elbows intermediate the drain and said treatment vessel, said elbows being arranged to form a retention column between them.

6. Apparatus as defined in claim 5, which includes a venturi in said siphon rinsing conduit at the top of said retention column for injecting rinsing fluid into said rinsing conduit and propelling it toward said treatment vessel.

7. Apparatus as defined in claim 4, wherein the elbow of the siphon rinsing conduit is disposed higher than the elbows of said siphon conduits connection said reservoirs to said treatment vessel in order to prevent flow of the baths through said siphon rinsing conduit.

8. Apparatus as defined in claim 4, which further includes a capillary siphon rinsing tube having its mouth at said treatment vessel disposed as near as possible to the lowest point in said treatment vessel in order to thoroughly empty the rinsing liquid from said treatment vessel.

9. Apparatus as defined in claim 1, wherein said reservoirs comprise hermetically enclosed containers, each including an expansible air chamber accessible from outside said container so that when pressure is applied internally of said chamber its volume increases to pressurize said container forcing the bath therein into said treatment vessel.