Monitoring apparatus and process for controlling composition of aqueous electrodeposition paint baths

Claim 2

In an apparatus for electrodepositing paint containing a receptacle adapted to hold a main body of an aqueous electrodeposition paint bath to which an electrical charge is applied to cause deposition of a coating of said paint, a monitoring device for continuously indicating the characteristics of said main body of said paint, said device comprising an electrically non-conducting conduit connected to said receptacle containing said main body of said paint which conduit is of sufficient length and diameter that the electrical charge on said main body of paint is negligible on liquid samples of said main body of paint carried in said conduit at the point where said conduit enters said monitoring device, a plurality of test probes in said conduit within said monitoring device at spaced intervals, said probes being connected to plural measuring means to continually monitor the conditions of said bath, said meaSuring means comprising means for measuring the condition of non-volatile matter concentration by the dielectric quality thereof, means for measuring temperature, means for measuring resistivity and means for measuring pH value, said measuring means further comprising means to provide electrical outputs responsive to said conditions, and means responsive to said electrical outputs for indicating such measurements to the operator of said device, said last named means including lamp circuits comprising three lamps for each said characteristic measured by said test probes one lamp indicating an optimum condition, another lamp indicating a minimum permissible condition and a third lamp indicating a maximum permissible condition, an electrical signal circuit activated by said electrical outputs from said test probes for each monitored characteristic and means operable in response to said electrical signal to illuminate said lamps selectively depending upon whether said monitored characteristic is the optimum condition, the minimum permissible condition or the maximum permissible condition.

Claim 3

A device as claimed in claim 3 in which said last named means comprises two photocells each illuminated by the lamp indicating the optimum condition, each cell having an associated shutter adapted to screen it from said lamp, means operable in response to said signal from said test probes to move said shutters to screen their respective cells when a minimum or maximum condition is reached and switching means operable in response to the screening of one of said cells to disconnect the electrical circuit through the lamp indicating an optimum condition and establish a circuit through the lamp associated with said screened cell.

Claim 4

In an apparatus for electrodepositing paint containing a receptacle adapted to hold a main body of an aqueous electrodeposition paint bath to which an electrical charge is applied to cause deposition of a coating of said paint, a monitoring device for continuously indicating the characteristics of said main body of said paint, said device comprising an electrically non-conducting conduit connected to said receptacle containing said main body of said paint which conduit is of sufficient length and diameter that the electrical charge on said main body of paint is negligible on liquid samples of said main body of paint carried in said conduit at the point where said conduit enters said monitoring device, a plurality of test probes in said conduit within said monitoring device at spaced intervals, said probes being connected to plural measuring means to continually monitor the conditions of said bath, said measuring means comprising means for measuring the condition of non-volatile matter concentration by the dielectric quality thereof, means for measuring temperature, means for measuring resistivity and means for measuring pH value, said measuring means further comprising means to provide electrical outputs responsive to said conditions, and means for indicating such measurements to the operator of said device, said last named means including a recorder, and manual and automatic selector switches commonly electrically connected with said recorder through a switching circuit, means to adjust said switches for ''''automatic,'''' ''''off,'''' and ''''manual'''' operation, and electrical signal circuit from the test probes for each monitored characteristic, and means to record the signals from said signal circuit on said recorder sequentially through said switching circuit.

Claim 5

Apparatus as claimed in claim 2 comprising electrical switching means connected to the output signals of said test probes for actuating means to correct a prescribed condition of said bath.