FR2519658A1 - Filtration appts., esp. for electroplating solns. - where filter strip is periodically fed from spool through filtering chamber so blocked strip can easily be replaced - Google Patents

Abstract

An electrolyte is fed by a pump and pipe into the top half of a chamber with a horizontal axis. The chamber is divided longitudinally by a horizontal, perforated plate, along which a filter strip can be driven. Each end of the chamber is closed by a removable lid. The top half of the chamber can be fed with compressed air; and the bottom half of the chamber has an outlet pipe for the filtered electrolyte. When the filter strip is blocked by sludge, the two lids are pref. opened manually or by motors, so a new filter strip can be drawn from a coil over the perforated plate. A valve is pref. included in the electrolyte inlet pipe. Very rapid and simple replacement of a blocked filter element without loss of soln..

Description

FILTRATION APPARATUS, PARTICULARLY FOR GALVANOPLASTY BATHS
The present invention relates to a filtration apparatus, in particular for electroplating baths.

In electrodeposition, the part to be covered is immersed in an appropriate cell containing a solution formed by a salt of the metal which must be deposited on said part.

It is well known that the solution contained in the cell or bath must be filtered continuously in order to remove the sludge and impurities formed in this solution.

In electrodeposition installations using conventional type filters, the gradual clogging of the filter results in a corresponding reduction in its filtering power.

This fact results in an increase in impurities in the bath resulting in a consequent increase in the consumption of additives and the need for frequent treatments for frequent regeneration of the bath. In addition, it can cause the production of defective parts which must then be discarded.

The replacement or washing of conventional type filters requiring prior emptying of the filtration chambers results in a significant loss of electrolyte.

In addition, another quantity of electrolyte is dispersed with the sludge which is generally removed when it is soaked with liquid.

It will be noted that the above-mentioned filter replacement operation requires significant labor, which greatly increases the operating cost of the installation.

One of the aims of the present invention is therefore to eliminate the drawbacks mentioned above by producing a filtration apparatus, in particular for electroplating baths, in which the operation of replacing the filter element can be carried out over a period of time. very reduced, by an operator only, or even automatically and without causing loss of solution.

The other objects of the invention are to provide a filtration device which can independently signal the passage of the value of the filtering power below a predetermined value, and therefore the need to replace the filter element. , in which the cleaning operations of the bath are very reduced and with which it is possible to obtain significant reductions in breakdowns and in the consumption of additives.

For these purposes, the filtration apparatus according to the invention is characterized in that it comprises a chamber having a horizontal axis, divided longitudinally by a perforated plate on which a ribbon having a suitable structure can be slid to form the filtration element, said chamber comprising at its two ends movable walls and communicating in its upper part with a supply line for the electrolyte to be filtered, withdrawn from the tank by means of a pump and an introduction pipe of compressed air and, in its lower part, with a duct for conveying the filtered electrolyte towards said tank.

The translation of the filter tape along the perforated plate and the opening of the movable walls of the ends of the chamber can be carried out either manually or automatically.

Other characteristics and advantages of this device will emerge from the description of a preferred embodiment and from the drawing in which
FIG. 1 is a schematic view of the filtration apparatus according to the invention in an embodiment with manual operation, during the filtration step,
FIG. 2 represents the apparatus of FIG. 1 during the step of replacing the filter element,
FIG. 3 represents an embodiment with automatic operation of the apparatus and,
FIG. 4 represents the replacement of the filter element in the apparatus of FIG. 3.

With reference to the figures, the filtration apparatus comprises a chamber 1 with a horizontal axis, in which a perforated plate 2 is disposed longitudinally.

This chamber 1 is closed at its two ends by movable walls 3 which can be removed either manually (fig. 1 and 2) by means of a screw and small flywheel assembly 4, or automatically (fig. 3 and 4) at the using a suitable motor 5.

The upper half of the chamber 1 communicates with a conduit 6, provided with a valve 7, intended to suck from a tank (not shown), by means of a pump 8, the solution which must be filtered.

The lower half of said chamber also communicates via conduit 9 with said tank.

A portion 10 of a rolled up filter tape 11 having characteristics such as the porosity and the composition suitable for the solution to be treated is placed on the perforated plate 2.

Therefore, in practice, the solution brought in a continuous pressure in the upper half of the chamber 1 is forced through the portion 10 of the filter tape, so as to be purified and to return to the tank by means of the conduit. 9.

When the portion of filter tape, during work, takes care of the mud and the filtering power reaches a given value and adjustable by means of a pressure switch, the pump is stopped automatically and the valve 7 is in the duct power supply 6 is closed.

In the case of a semi-automatic device, as represented by FIGS. 1 and 2, a particular system blows compressed air into the chamber 1 through the opening 12 so as to empty said chamber, a lamp and / or an acoustic signal 13 being provided to attract the attention of the operator.

The operator will then open the movable walls 3 by actuating the flywheel 4 and will advance the clean filter using a crank 14 while the mud will fall into the container 15.

The operator will then close the walls by pressing a button on the control panel to start a new filtration cycle.

Similarly, in the automatic type device shown in Figures 3 and 4, when the pump 8 stops under the control of a pressure switch or a timer, a pneumatic valve 16 is opened, so as to allow with compressed air, brought through a line 17, to push the solution located in the chamber 1, through the filter 10, through the conveying line, to the tank.

 After emptying the chamber, a timer closes the valve 16 and the movable walls are open.

A motorized roller 18 drives the spent filter portion outside the chamber, while the waste is removed by a doctor blade, separated from the filter and falls with the latter into a small collecting tank 19.

After the installation of a new filter portion in the chamber 1, the movable walls 3 are closed and the pump 3 automatically performs a new filtration cycle.

It will be noted, of course, that this device has been described by way of an indicative and nonlimiting example and that this invention is susceptible of numerous modifications and variants obvious to those skilled in the art.

Claims (5)

Claims 1. A filtration apparatus, in particular for gålwanoplasty baths, characterized in that it comprises a chamber (1) having a horizontal axis, divided longitudinally by a perforated plate (2) on which a ribbon (11) having a structure suitable for forming the filtration element, said chamber comprising at its two ends movable walls (3) and communicating in its upper part with a supply duct (6) of the electrolyte to be filtered, withdrawn from the tank by means of a pump (8) and a pipe for introducing compressed air and, in its lower part, with a pipe (9) for conveying the filtered electrolyte to said tank. 2. 1A filtration device according to claim 1, characterized in that the translation of the filter tape (11) along the perforated plate (2) and the opening of the movable walls (3) disposed at the ends of the chamber (1) can be performed either manually or automatically. 3. Filtration device according to any one of the preceding claims, characterized in that there are valves on the supply pipes for the solution to be filtered and for the introduction of compressed air, controlled, according to an appropriate sequence by a pressure switch or a timer controlling the stopping of the supply pump (8).  4. A filtration apparatus according to any one of the preceding claims, characterized in that the filter tape (11) has characteristics such as porosity and composition, suitable for the solution to be treated. 5. A filtration device according to any one of the preceding claims, characterized in that it comprises, in the embodiment with semi-automatic operation, an optical and / or acoustic device (13) for signaling to the operator the need to intervene.