US3763028A

US3763028A - Vee notch weir level control system

Info

Publication number: US3763028A
Application number: US00654436A
Authority: US
Inventors: J Rverson; T Wall
Original assignee: Oxy Metal Finishing Corp
Current assignee: OMI International Corp; Oxy Metal Finishing Corp
Priority date: 1967-07-19
Filing date: 1967-07-19
Publication date: 1973-10-02
Anticipated expiration: 1990-10-02

Abstract

IN THE ILLUSTRATED EMBODIMENT THE LEVEL OF A PLATING SOLUTION IS ADJUSTABLY DETERMINED BY METERING FLOW TO THE PLATING TANK WITH A VALVE EQUIPPED WITH A MICROMETER SCALE INDICATING THE VALVE ORIFICE AREA OPENING AND PROVIDIN G FOR THE CONTINUOUS OVERFLOW FROM THE PLATING TANK THROUGH A V NOTCH WEIR. OBSERVED MICROMETER READINGS ON THE METERING VALVE WILL PRODUCE CORRESPONDING PRECISE AND PREDICTABLE LEVELS OF THE PLATING SOLUTION OVER THE HEIGHT OF THE V NOTCH.

Description

United States Patent Ryerson et al.

1 1] 3,763,028 1 Oct. 2, 1 973 VEE NOTCH WEIR LEVEL CONTROL 2,891,574 6/1959 Dahlberg 137 577 SYSTEM 3,480,025 11/1969 Hsu et al l37/563 2,962,427 "/1960 Kosowsky 204/237 [75] Inventors: James N. Ryerson,0eeanport; 3,168,457 2/1965 Grazen 204/237 Theodore R. Wall, Elizabeth, both 3,259,557 7/1966 Smith ct all 204/237 fN J 3,296,! 14 1/1967 Lloyd 204/237 [73] Assignee: a," gf g Corporation Primary Examiner-Winston A. Douglas amen Assistant Examiner-C. F. Lefevour Filed: July 19, 196 Attorney-Hill, Sherman, Meroni, Gross & Simpson [21] Appl. No.: 654,436

[57] ABSTRACT [52] U.S. Cl. 204/237 In the illustrated m ment the level f a plating so- [51] Int. Cl 801k 3/00 lutlon is ju tably determined by metering flow to the [58] Field of Search 204/237, 238, 239, p ng tank h a v l eq ipped with a micrometer 204/232, 233, 234, 235, 236; l37/563, 577 scale indicating the valve orifice area opening and pro- 1 viding for the continuous overflow from the plating [56] References Cited tank through a V notchweir. Observed micrometer UNITED STATES PATENTS readings on the metering valve will produce corre- 2 590 538 3/1952 Huck 37/563 sponding precise and predictable levels of the plating 2:690:764 10/1954 Hoffmann. 137/563 over the v 2,743,909 5/1956 Lawlor 137/563 8 Chims, 3 Drawing Figures 2 i a x Q it I I l I 1 '1 "H1 l 1 l'* *7 ill r'- --l--. l--

I I 22 j! "53 .14 15 w l 1 i 35 Z6 27 U 3 .5 i 2.9 1 writ IE f5 PATENTED 2 I975 IN VEN TORS James AZ 12396225022 7%0Q02 6/E W22 5) E $24 ATTORNEYS VEE NOTCI-I WEIR LEVEL CONTROL SYSTEM BACKGROUND OF THE INVENTION In the plating art, and particularly in the plating of electrical components with precious metals, there is a great need for precision control and adjustment of the level of the plating solution. In certain applications the parts to be plated are conveyed across the plating solution, and if the level of the plating solution is not continuously controlled with great precision, either the parts are only partially plated or the parts are plated to a greater height than functionally necessary. With insufficient plating height, the part would not meet requirements, while with excess plating height precious plating material is wasted creating an economic loss which may be of substantial commercial significance. Further excess plating height may cause an actual deterioration in performance of electrical components and the like, even where the waste of material is not a substantial factor.

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a precisely adjustable system for controlling liquid level in a plating tank or the like.

Another object of the invention is to provide such a system having a precision and repeatability of adjustment substantially exceeding that available in prior art systems of comparable cost and simplicity.

A further object of the invention is to provide such a system wherein a single adjustment is required and wherein a visual indication is given which may be reliably correlated with a desired liquid level.

Other objects, features and advantages of the present invention will be apparent from the following detailed description taken in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat diagrammatic illustration of an overall liquid level control system in accordance with the present invention;

FIG. 2 is a somewhat diagrammatic vertical sectional view taken generally along the line 11-11 of FIG. I; and

FIG. 3 is a diagrammatic top plan view of the system of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT A generally rectangular plating tank is genera indicated at having an interior wall 11 serving as a weir with an outlet means 12 in the form of a V-shaped notch. While the plating tank may have any desired configuration, it is diagrammatically indicated as having a front wall 14, side walls 15 and 16, a rear wall 17 and a bottom wall 18. For the sake of diagrammatic illustration, it may be assumed that overflow compartment 20 is defined by weir 1 l, a central portion of front wall 14, and connecting

wall portions

22 and 23. A chamber for receiving the plating solution is that portion of the plating tank 10 excluding the overflow compartment 20. An exemplary level for the plating solution in the chamber is indicated by the reference numetal 25 in FIG. 2.

In the illustrated embodiment, a sump tank is indicated at 26 having a minimum liquid level such as indicated at 27 and provided with a circulation pump as indicated at 29 for supplying the plating liquid from the tank 26 to the plating tank 10. The input line to the plating tank is indicated diagrammatically at 30 and a micrometer indicating metering valve is indicated at 32 for adjustably determining the rate of flow of the plating liquid to the tank 16. The metering valve 32 is equipped with a micrometer scale indicating the valve orifice area opening and is manually adjustable by means diagrammatically indicated at 33. The system is so constructed that there is a continuous flow of the plating liquid into the chamber of plating tank 16 via input line 30 with liquid in the plating tank continuously flowing through the V notch 12 and into the overflow compartment 20 from which liquid returns via return line 35 to the sump 26.

The capacity of the pump 29 is such that with the metering valve 32 fully open, the level 25 in the plating tank 10 will be maintained at the full overflow capacity of the V notch 12, that is at least substantially at the level of the top surface 37 of weir 11. By reducing the orifice area of the metering valve 32, the flow rate is reduced until the level such as indicated at 25 of the plating solution is only slightly above the lowermost point such as indicated at 38 of V notch 12. Thus,-the range of adjustment of the metering valve 32 corresponds to a range of plating solution levels over the effective height of the V notch 12. Over this operating range, there is a continuous overflow of plating solution through the V notch 12 and into the overflow compartment 20.

Observed micrometer readings on the metering valve 32 will produce precise and predictable levels such as indicated at 25 in the plating tank for the range of plating solution levels corresponding to the height of the V notch 12.

Thus, if for a given type of workpiece to be plated, the workpiece is to be moved through the plating solution at a predetermined level relative to the upper edge of the plating tank 10, then the setting of the manual adjustment means 33 of the metering valve 32 which provides the desired level of the plating solution can be noted, and the metering valve 32 reset to this value on the micrometer scale whenever the particular workpiece is to be plated. Further, the level of the plating solution relative to the top edge of the tank 10, for example, may be determined for various settings of the metering valve 32, and thereafter a reliable precisely predictable level of the plating solution may be selected simply by setting of the metering valve 32 to the corresponding micrometer reading. This feature of the illustrated system greatly facilitates the adjustment of plating equipment to handle different types of workpieces and the like in quick succession.

To place the system in operation, with the working chamber 39 of the plating tank. filled to a level at the bottom point 38 of the V notch 12 and with the sump 26 filled to capacity, the circulation pump 29 is started. Liquid pumped from the sump tank 26 up to the plating tank 16 is metered by the micrometer indicating metering valve 32. The liquid level rise produced in the plating tank overflows through the V notch 12 into the overflow compartment 20, FIG. 2, and returns by gravity through return line 35 to the sump. The liquid level produced in the plating tank is a function of the orifice opening in the metering valve ;32 versus the overflow capacity of the V notch 12. As previously stated, with the valve 32 fully open, the capacity of pump 29 is such as to produce a level in the plating tank equal to the full overflow capacity of the V notch, this level being indicated at 37 in FIG. 1. Observed micrometer readings on the metering valve 32 will produce precise and predictable levels in the plating tank, adjustable through the depth of the V notch 12.

It will be noted that the V-shaped notch provides a generally triangular cross section liquid flow path which flow path has a more than linear increase in flow area as a function of increasing liquid level in the working chamber 39 of the plating tank. More specifically, the flow area provided by the notch 12 increases approximately as the square of the height of the plating bath above the bottom of the notch.

Further details of construction and operation of the plating tank and the plating system to which the present invention applies are found in the copending applications Ryerson et al US. Ser. 310,274 filed Sept. 20, 1963 and Ryerson et al U.S. Ser. 433,029 filed Feb. 16, 1965, and the disclosures of both these applications are incorporated herein by reference in their entireties. These applications specifically disclose a plating system wherein different types of work units are to be transported at different times across the plating bath at a predetermined level with portions of the work units immersed in the plating bath for the purpose of being plated over respective predetermined extents thereof. Utilizing the features of the present invention, as the plating system is adjusted to work units requiring different plating bath levels, the metering valve 32 is set to corresponding predetermined settings as determined from the micrometer scale thereof, thus simplifying and expediting the changeover of the system to different types of work units.

It will be apparent that many modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. A plating chamber with a liquid level control system comprising a tank having a working chamber for containing a liquid,

an input line for supplying liquid to said working chamber, said chamber having a weir with a fixed area, generally V-shaped notched outlet means for controlling discharge of liquid from said chamber,

a sump tank constructed to receive liquid from the working chamber,

a pump connected to the sump tank and having an output operable to supply liquid under pressure at said output for delivery to the working chamber of 50 said metering valve.

said tank,

flow control means comprising a micrometer indicating, metering valve between the pump output and the tank input for metering the flow of liquid to the working chamber of said tank,

said weir outlet means being shaped to provide a more than linear increase in flow area as the function of increasing liquid level in the working chamber of said tank,

the relation between the capacity of said pump, the

metering valve and said weir outlet means being such as to provide a predictable change in liquid level in said chamber at different settings of said metering valve and to maintain a substantially constant level in said chamber at each different setting of said valve during continuous circulation of liquid to and from said chamber.

2. The system of claim 1 with said weir outlet means providing a generally square law increase in flow area as a function of increasing liquid level in the working chamber of said tank.

3. The system of claim with said tank containing a plating liquid and having means for plating said material on workpieces partially immersed in said plating liquid, and said weir outlet means providing a substantially square law increase in flow area as a function of the level of said plating liquid in said working chamber.

4. The system of claim 1 with said flow control means comprising an adjustable metering valve providing for adjustment of the flow area of said valve and having a micrometer scale indicating said setting.

5. The system of claim 3 with said flow control means comprising an adjustable metering valve providing a micrometer adjustment of the flow area of said valve.

6. The system of claim 1 with said weir outlet means comprising a V shaped notch, and said flow control means comprising an adjustable metering valve providing a micrometer adjustment of flow area.

7. The system of claim 3 with said weir outlet means comprising a V-shaped notch and said flow control means comprising an adjustable metering valve providing a micrometer adjustment of the flow area of said valve.

8. The system of claim 7 in which the relation between said pump capacity and said weir outlet area is such as to maintain the level of said plating bath near the top of said V-shaped notch with said micrometer valve fully open and being operative to maintain the level of said plating path near the bottom of said V- shaped notch with a minimum orifice adjustment of