US3607546A

US3607546A - Apparatus for acid polishing or like treatment of glass articles

Info

Publication number: US3607546A
Application number: US778581A
Authority: US
Inventors: Michael Grealey
Original assignee: Stevens and Williams Ltd
Current assignee: Stevens and Williams Ltd
Priority date: 1967-12-15
Filing date: 1968-11-25
Publication date: 1971-09-21
Anticipated expiration: 1988-09-21
Also published as: BE725487A; IE32896L; DE1813291A1; GB1209459A; IE32896B1; FR1596871A

Abstract

Apparatus for acid-polishing glassware by loading the articles into a revolving cage or cages having a movement in a vertical plane. Each cage is divided into peripherally spaced pockets or compartments to receive glasses, the pockets facing in opposite directions so that articles are placed in position as the pocket is moving in a downward path, discharge which takes place on the upward path, being semiautomatic utilizing gravity. The machine is emptied by a simple semiautomatic transfer system where the glasses are automatically transferred into a duplicate apparatus for swilling (second stage) final demineralized swilling (third stage) and hot air drying (fourth stage), producing the finished article with a minimum of labor and effort and to a high standard of quality.

Description

United States Patent APPARATUS FOR ACID POLISHING OR LIKE TREATMENT OF GLASS ARTICLES 12 Claims, 7 Drawing Figs.

US. Cl. 156/345, 156/24, 65/31, 134/33, 134/79, 134/134, 134/159 Int. Cl. C03c 15/00 Field of Search 156/345, 24, 25; 65/31; 134/25, 32, 33, 66, 79, 83,134, 159, 166

[56 1 References Cited UNITED STATES PATENTS 721,233 2/1903 Prince 134/66 FOREIGN PATENTS 142,494 12/1959 U.S.S.R. 134/66 1,546,081 5/1969 Germany 134/66 Primary Examiner-Jacob l-l. Steinberg Attorney-Baldwin, Wight & Brown ABSTRACT: Apparatus for acid-polishing glassware by loading the articles into a revolving cage or cages having a movement in a vertical plane. Each cage is divided into peripherally spaced pockets or compartments to receive glasses, the pockets facing in opposite directions so that articles are placed in position as the pocket is moving in a downward path, discharge which takes place on the upward path, being semiautomatic utilizing gravity. The machine is emptied by a simple semiautomatic transfer system where the glasses are automatically transferred into a duplicate apparatus for swilling (second stage) final demineralized swilling (third stage) and hot air drying (fourth stage), producing the finished article with a minimum of labor and effort and to a high standard of quality.

PATENTED SEPZI 15m sum 1 SF 5 mm gum; .5y 5m a; 521w PATENTED SEPZ] 1971 SHEET 2 1F 5 PATENTEU SEPZ] SiiEET h 1F 5 APPARATUS FOR ACID POLISHING OR LIKE TREATMENT OF GLASS ARTICLES Over the past 50 years hand-cut and machine-cut glassware has received its final polish by immersion in an acid bath which consists of a mixture of sulfuric and hydrofluoric acids. In practice this is carried out by hand-dipping, although in more recent years it has been partly mechanized by placing the articles into racks or cages of various shapes and sizes, the racks or cages then being loaded by crane in the acid bath and if necessary activated. One of the disadvantages of this method is that glasses are likely to receive rack marks or otherwise become scored.

According to the present invention, apparatus is provided for polishing glass articles by immersion in an acid bath the articles being placed one by one in separate open access containers or compartments in a container, constrained to follow an orbital path about a horizontal or substantially horizontal axis and so arranged in relation to the bath that they remained immersed for part only of their path, the articles being restrained against release from their respective containers or compartments so that when in motion, they will normally be retained therein but which permits of their discharge semiautomatically utilizing gravity.

Glass-polishing apparatus according to this invention comprises an immersion tank for an acid bath, a cage mounted for rotation about a substantially horizontal axis so arranged that the articles remain immersed for part only of their path and are restrained against release from their respective containers or compartments so that, when in motion, they will normally be retained therein but which permits of their discharge semiautomatically utilizing gravity.

The invention is illustrated in the accompanying drawings in which:

FIG. 1 is an elevation and FIG. 2 is a plan view of a glass-polishing plant having three baths to permit of a three-stage process, a fourth or drying stage being omitted.

FIG. 3 is an end elevation of the plant, the fume extractor of bath No. 1 not being shown either in FIGS. 2 and 3.

FIG. 4 is a vertical elevation of a cage or rack.

FIG. 5 is a section on the line V-V of FIG. 4 of an individual cage or rack showing a preferred construction of the pockets or compartments for the articles, and

FIG. 6 is a transverse section on an enlarged scale showing a vat and cage.

FIG. 7 is an explanatory sectional view showing the bath and cage.

Referring to the accompanying drawings there is shown an acid-polishing unit made up of a series of three baths, each bath comprising a vat 1 for the acid or other liquid and mounted to revolve in each of which vats is a cage, indicated generally at 2, the cage 2 being provided around its perimeter with open top pockets 10 or compartments to receive glass articles to be polished, these usually being glasses.

In the embodiment illustrated each cage has four processing lanes provided by four racks, indicated respectively at 3, 4, 5 and 6 and it will be noted that the several racks are of varying width so as to accommodate articles, e.g. glasses of different sizes. Mounted above the acid bath is a fume extraction cowl 30.

The cage is mounted to revolve about a horizontal axis 7 located in a plane above that of the top of the vat so that only the perimeter of the cage, not substantially less than half is, at any one time, when revolving immersed in the acid bath. In practice, satisfactory results have been achieved using a bath level such that slightly less than half the cage is immersed, since this allows me into operation to effect discharge of articles successively from their several pockets as the latter approach the horizontal. By exposing the upper part of the cage it is a simple operation toload articles to be. polished one at a time into the several pockets, at a loading station indicated at B in FIG. 1 as each pocket approaches the operator.

Likewise as explained below, removal of the articles, or

transfer from one lane to the corresponding lane in the cage of the next bath can be made semiautomatic. The pockets 10,

which may be spaced around the perimeter of each rack at equal intervals are formed with angled sidewalls 11, so that the plane of the wall, when each pocket reaches the horizontal, i.e., passes through the horizontal plane XX containing the axis of rotation of the cage, is still at an angle Y (FIG. 4) to the horizontal with the result that an article suitably placed in the pocket will be discharged at point A (FIG. 7). The glass or other article G at this time will have taken up a position on the sidewall 11 at the mouth or open end of the pocket 10 in which it is also supported by a rotor shield 12 as hereinafter described.

The function of the shield 12 is to retain articles within their respective pockets during their period of immersion, the shield cooperating successively with individual pockets to provide compartments, the latter being perforated to permit of circulation of acid into and out of the compartment.

As the cage continues to revolve a rotary or rolling motion, which is anticlockwise, will be imparted to a glass or other article so that immediately the sidewall of the pocket (indicated at G in FIG. 7) reaches the position where it is level with the lip 13' of the sidewall of the vat it will be free to continue its rolling motion and be discharged, provided a gate 21, hereinafter described, has been elevated.

Furthermore, as a pocket moves from the highest point of its orbit to the horizontal, the glass, which is at the bottom of the pocket, will commence to roll towards the mouth end but due to the changing angle of the pocket sidewall the rolling motion is arrested and changes in direction, thus eliminating any permanent contact of one part of the glass with the pocket wall.

It will be found that by rounding the bottom of each pocket to a suitable contour l6, movement of the article within the pocket as the racks revolve is a relatively gentle one, with consequent reduction in noise of operation.

Under normal acid polishing conditions, a skin or surface crust forms on the inside and outside of the glass when immersed in the acid, which, unless it is removed, inhibits the polishing and may even produce blemishes or inequalities in the surface.

To overcome this and ensure acid circulation both in the bath itself and the interior of the glass, one at least, and preferably both side walls in each pocket are apertured. By using plastics sheeting having perforations the inflow and outflow of acid (and of water in the washing stages) to the pocket is relatively rapid and sufficient to prevent formation of a crust on the glass, since the products of reaction are prevented from adhering to the glass, being swept away by the swirling action of the acid so that fresh surfaces are continuously exposed to the acid-polishing.

Providing perforations in the shield 12 makes acid available for polishing from both sides of the shield, and further assists in keeping polishing times within reasonable bounds and improves the polishing standard.

At 4-5 r.p.m., as each pocket lifts, the acid can be seen streaming out through the perforations in the sidewall. Failure to provide for release of acid from a lifting pocket would necessitate operation at a lower r.p.m. so as to ensure complete evacuation of the acid or operation at a lower level of acid in the vat with consequent reduction in output to prevent acid from being carried over in the pocket.

In the preferred embodiment as shown in FIGS. 4 and5, the acid or other liquid in the bath has direct inflow to and outflow from the article within the pocket or compartment, both the end (or partition) walls 17 of the individual racks being perforated as at 17' as are also the sidewalls 11 of each compartment, as indicated at 18.

The perforated shield 12 is semicircular and, depending upon the speed of rotation and the pocket formation (see FIGS. 1 and 7), on the loading side extends to a level at or adjacent to the horizontal plane, as indicated at 13 thus ensuring that articles within the pockets cannot fall out until the angular position of sidewall 11 is at a positive angle to the horizontal. It will be understood, however, that as the cage revolves and successive socket undersides change from an upwards to a downwards inclination each article will for a part of its downwards path roll onto the sidewall which is undermost until the pocket moves into the cover afforded by the shield 12 when it will rest on the shield, the walls of the pocket at this time acting as a scoop or paddle until such time as the pocket is rising when the article is once again carried by the sidewall now undermost.

On the loading side in vat 1 the shield 12 may extend to a level slightly above the horizontal plane passing through the rotation axis depending upon the size of the cage.

To impart rigidity to the shield 12, which, together with the vat may be formed of plastic material, eg high density polythene, this is reinforced by ribs 20. 35 indicates an immersion heater and 37 spray pipes. Axles for each cage are individually mounted in support bearings mounted on pedestal brackets 36 on the platform 26 of the structure.

Discharge or release of wine glasses, tumblers, small vases and other round articles from the pockets in the racks making up the cage can take place automatically. As the pockets successively approach the discharge point A, at which time the angular position of the wall 11 is still at an angle to the horizontal, due to gravity the article will tend to slide or in the case of a circular glass roll down the incline. Due also to the relative rotation of the cage and shield, the article will itself be subjected at its periphery to an angular thrust with the result that it tends to revolve anticlockwise. Accordingly if no restrain acts on the article to retain it in its pocket, the article will discharge itself automatically by rolling out of the pocket.

To control the period of retention within the pockets, provision is made for extending the shield 12 to a level above the horizontal. This extension in the case of vat 1 takes the form of the gate 21 of arcuate section which normally during processing of articles in the bath is positioned as shown in FIG 1 to provide an extension of the shield 12, the size of the gate being sufficient to prevent articles rolling out of the pockets as they successively ascend towards the horizontal The gate 21 conveniently is adjustably supported on the end of radius arms 22 mounted to swing about a center coincident with the axis rotation of the cage. Since processing times for different articles in the respective lanes will vary, independent operating gates may be provided for the several lanes.

In the arrangement shown for stage III one or both arms 22 is or are provided with a stop pin 23 which rides in an arcuate slot 24 in a plate 25 carried by a platform forming part of a superstructure 27, surrounding the vat. Cooperating with the the stop pin 23 on one side is a latch 33 so that the release gate (or gates) 21 can be held in an elevated position above a level where successive pockets, one of which is indicated 31, (See FlG. I) arrive in the discharge position, and in which position articles will be permitted to discharge automatically. Similar arrangements are provided for stages I and ll.

Provision may be made for individual control of gates at stage I so that a different polishing time may be selected for each of the several lanes in the cage. The gates in successive stages may however be controlled as a single unit as washing times are not so critical.

It will be noted that the vats 1 are supported in their respective frames at different levels, the vats of stages II and 11] being at successively lower levels below that of stage I, thus allowing articles on discharge from the cage of stage I to be discharged directly into the pockets of the corresponding racks in the cage of stage I1 and so on.

in operation the apparatus is set to ensure that the cages containing the articles to be acid polished, revolve for the required immersion time in the acid bath.

a, The rotation of the respective cages at all three stages is clockwise as viewed on the drawings.

b. Articles e.g. glasses are loaded by hand into the pockets at station B.

c. the glasses are ejected or expelled at station A when the gate 21 is open because:

1. They are at maximum distance from center of rotation of the cage i.e. at the outside of the pocket;

2. They are under the influence of forces shown in FIG. 7;

3. They are rotating anticlockwise.

d. The glasses are not ejected at point B, because:

l. At rotor speeds of 3-5 r.p.m. there is not sufficient time for them to roll from their position at the bottom of the pocket which is a minimum distance from the center of rotation. The extension of the rotor shield at point B would provide for retention of glasses if the rotor was stationary or driven at lower speeds.

It follows therefore that labor can be reduced to a minimum since an operator can readily place articles within the pockets of the several racks of the cage in stage 1. On completion of the immersion time, the racks 3 to 6 can be emptied by hand or in a three or other multiple-stage proce is by raising the gate to allow articles to discharge by gravity from the respective pockets in the racks of stage 1 to those of stage 2 (swilling) and from stage 2 to stage 3 (demineralized swilling). If desired a fourth stage may be added for hot-air drying. Drive to the several cages is not shown but it will be nderstood that they may be rotated in synchronism from a coriimon drive at speeds varying from 3-5 rpm. 1

A further advantage arising from the apparatus of this invention lies in the fact that the glasses a e supported during polishing, by point or line contacts on their surfaces which are constantly changing. The time that a glass is supported at any one point or line is thus kept to a mininrum. If a glass is not free to move from its support during pol shing then the reaction between acid and glass is inhibited at he point of contact.

What is claimed is: l

1. Apparatus for acid-polishing or like lireatment of glass articles by immersion in an acid bath comprising an immersion tank, a cage mounted for rotational movement about a substantially horizontal axis and so position d in relation to the level of the bath that the cage is immerse for less than but not substantially less than half of its pat the cage having peripherally spaced pockets to receive individual articles to be polished, each of said pockets comprisi g two walls spaced from each other peripherally of said cage and extending outwardly from the inner portion of the cage and terminating in peripherally spaced relation to each other at the periphery of the cage, whereby the pockets are open-eiided to permit insertion and removal of articles while the dage is in motion, at least one of said walls of each of said poclrets being perforated whereby to enhance drainage of acid from the pocket upon elevation of the latter above the bath, sa d pockets being of a size relative to an article placed therein to permit of unrestricted rolling movements of the articles in contact with the pocket walls, a shield of semicircular formation spaced from the perimeter of the cage and which cooperates therewith to provide a perforate enclosure to allow tlirough flow of liquid into and out of individual pockets, the shield being mounted under said cage, whereby articles in the pockets when moving in the downwards direction in the bath will be contacted by said shield and caused to rotate within the pockets and will be retained in the pockets during immersion, the articles, on leaving the bath and being elevated above said shield, being removed or assisted in removal from the pockets by gravity, and a movable gate for controlling such removal of the articles from the pockets. 1

2. Apparatus as claimed in claim 1 wherein the pockets are provided with drainage openings in at least two walls thereof to permit inflow and outflow of liquid and the shield has opening means to permit downward discharge of sludge from the upper surface of the shield through the latter and into the acid bath.

3. Apparatus as claimed in claim 2 wherein the cage comprises perforated partition walls.

4. Apparatus as claimed in claim I in which said shield is perforated. Y

5. Apparatus as claimed in claim 1 in which the shield terminates at a level below the horizontal axis of the cage whereby articles, as the pockets successively move to a position above the shield, may be released from the pockets.

6. Apparatus as claimed in claim 5 wherein said shield is perforated and said pockets have perforated side and end walls.

7. Apparatus as claimed in claim 1 wherein said gate is of arcuate formation for cooperation with the shield, the gate being positioned to retain articles withing the pockets of the cage as the pockets move beyond the shield.

8. Apparatus as claimed in claim 7 in which the movable gate comprises a plate of arcuate section, the gate being supported for movement from an operative article-retaining position to and from a release position in which articles are permitted to fall from pockets by gravity.

9. Apparatus as claimed in claim 8 in which a latch device is provided for holding the gate in its release position.

10. Apparatus as claimed in claim 1 in which the cage comprises racks provided with pockets which differ in size.

11. Apparatus as claimed in claim 1 in which the pockets comprise sidewalls in the form of a V and have a curved bottom.

12. Apparatus as claimed in claim 1 in combination with an additional bath means provided with a cage having pockets to receive articles following acid-polishing and wherein the articles are subjected to further treatment including washing.

Claims

2. Apparatus as claimed in claim 1 wherein the pockets are provided with drainage openings in at least two walls thereof to permit inflow and outflow of liquid and the shield has opening means to permit downward discharge of sludge from the upper surface of the shield through the latter and into the acid bath.
3. Apparatus as claimed in claim 2 wherein the cage comprises perforated partition walls.
4. Apparatus as claimed in claim 1 in which said shield is perforated.
5. Apparatus as claimed in claim 1 in which the shield terminates at a level below the horizontal axis of the cage whereby articles, as the pockets successively move to a position above the shield, may be released from the pockets.
6. Apparatus as claimed in claim 5 wherein said shield is perforated and said pockets have perforated side and end walls.
7. Apparatus as claimed in claim 1 wherein said gate is of arcuate formation for cooperation with the shield, the gate being positioned to retain articles withing the pockets of the cage as the pockets move beyond the shield.
8. Apparatus as claimed in claim 7 in which the movable gate comprises a plate of arcuate section, the gate being supported for movement from an operative article-retaining position to and from a release position in which articles are permitted to fall from pockets by gravity.
9. Apparatus as claimed in claim 8 in which a latch device is provided for holding the gate in its release position.
10. Apparatus as claimed in claim 1 in which the cage comprises racks provided with pockets which differ in size.
11. Apparatus as claimed in claim 1 in which the pockets comprise sidewalls in the form of a V and have a curved bottom.
12. Apparatus as claimed in claim 1 in combination with an additional bath means provided with a cage having pockets to receive articles following acid-polishing and wherein the articles are subjected to further treatment including washing.