CA2560337A1

CA2560337A1 - Process and apparatus for the electrogalvanic coating of metal items

Info

Publication number: CA2560337A1
Application number: CA002560337A
Authority: CA
Inventors: Umberto Spina; Walter Lando
Original assignee: Individual
Current assignee: LM Finishing Systems Srl; Glomax Srl
Priority date: 2004-03-23
Filing date: 2004-03-23
Publication date: 2005-09-29
Anticipated expiration: 2024-03-23
Also published as: MXPA06010926A; CN1942609A; HK1104325A1; BRPI0418677A; CA2560337C; EP1730329A1; JP2007530782A; JP4505501B2; CN100564611C; WO2005090647A1; US20070246369A1

Abstract

In a process for the electrogalvanic coating of metal items through a sequence of chemical or electrochemical treatment phases, each of said treatment phases includes the following steps: a) introducing the drum containing the items into a centrifuge; b) delivering a first chemical treatment liquid to the centrifuge; c) carrying out the treatment; d) draining said first chemical treatment liquid from the centrifuge; e) carrying out a centrifugation of the items to recover said liquid; f) delivering washing water to the centrifuge;
g) carrying out the washing; h) draining the washing water from the centrifuge; i) carrying out a centrifugation of the items to recover said water; j) transferring the drum to another station, or repeating the preceding steps with another chemical treatment liquid. Carrying out the washing subsequent to a chemical treatment phase in the same station where the treatment has been carried out allows to significantly reduce the number of stations, moreover the centrifugation subsequent to every treatment or washing allows to recover the liquids thus reducing the consumption thereof, as well as to prevent the problems of liquid carry-over from one station to another, which also prevents the environmental pollution. A plant that embodies said process consists of a sequence of aligned stations (A), with an automatic loading station at the inlet and an automatic unloading station at the outlet, in which the items to be treated are contained in perforated cylindrical drums (D) open at the top that are automatically moved from one station to another by means of carriages (C) that run on rails (B) extending above the stations along the whole length of the plant. The use of open drums (D), instead of the conventional barrels closed by a door, allows to carry out in a completely automatic way the loading and unloading of the items in the plant end stations with a great saving of labour force as well as with no risks to the health of the operators.

Claims

1. Process for the electrogalvanic coating of metal items through a sequence of chemical or electrochemical treatment phases, characterized in that each of said treatment phases includes the following steps:
a) placing the items to be treated into a centrifuge;
b) delivering a treatment liquid to the centrifuge;
c) carrying out the treatment;
d) draining said treatment liquid from the centrifuge;
e) carrying out a centrifugation of the items to recover said liquid.

2. Process according to claim 1, characterized in that it further includes the steps of inclining the centrifuge, preferably at about 45°, prior to carrying out the treatment and of returning the centrifuge to the vertical position prior to the centrifugation.

3. Process according to claim 1 or 2, characterized in that the treatment liquid is washing water and in that the first step of placement of the items in the centrifuge consists in leaving the items in the centrifuge where the preceding treatment has been carried out.

4. Process according to one of the preceding claims, characterized in that a plurality of chemical or electrochemical treatments and the relevant subsequent washings are carried out sequentially in the same centrifuge.

5. Apparatus for the electrogalvanic coating of metal items, characterized in that it includes a vertical axis centrifuge (F) with a removable drum (D) open at the top, means for the hydraulic connection to delivery (G) and drain (H) pipes for treatment liquids to be delivered to and drained from said centrifuge (F), as well as one or more tans (T, T') for storage and recovery of said treatment liquids with relevant valve and pump means, and possibly a current rectifier (R) electrically connected to the centrifuge (F).

6. Apparatus according to claim 5, characterized in that it further includes means (M) to incline the centrifuge (F), preferably at about 45°, around a horizontal axis (X).

7. Apparatus according to claim 5 or 6, characterized in that the delivery (G) and drain (H) pipes converge into a hydraulic connector (S) extending from the bottom of the centrifuge (S).

8. Apparatus according to one of claim 5 to 7, characterized in that the delivery pipe (G) comes from an upper tank (T) located on a scaffolding (K) at an elevated position with respect to the centrifuge (F), whereas the drain pipe (H) leads to a lower tank (T') located lower than the centrifuge (F) under said scaffolding (K).

9. Plant for the electrogalvanic coating of metal items, characterized in that it includes a sequence of aligned stations (A) consisting of apparatuses according to one of claims 5 to 8, with an automatic loading station (L) at the inlet and an automatic unloading station (U) at the outlet, the latter being preceded by two drying stations (A').

10. Plant according to claim 9, characterized in that it further includes carriages (C) that run on rails (B) extending above the stations along the whole length of the plant, said carriages (C) being provided with means for moving the drums (D) from one station to another.