US3162986A

US3162986A - Method and apparatus for feeding abrasives

Info

Publication number: US3162986A
Application number: US252374A
Authority: US
Inventors: Olivieri Luigi
Original assignee: COMPATNIE DE SAINT GOBAIN
Current assignee: COMPATNIE DE SAINT GOBAIN; COMPATNIE DE SAINT-GOBAIN
Priority date: 1962-02-06
Filing date: 1963-01-18
Publication date: 1964-12-29
Anticipated expiration: 1981-12-29

Description

Dec. 29, 1964 OLIVIERI 3,162,986

METHOD AND APPARATUS FOR FEEDING ABRASIVES Filed Jan. 18, 1963 2 Sheets-Sheet 1 INVENTOR. LUIGI 0L| VIERI A TTOR EYS Dec. 29, 1964 I OLlVlERl 3, 62,98

METHOD, AND APPARATUS FOR FEEDING ABRASIVES Filed Jan. 18, 1963 2 Sheets-Sheet 2 INVENTOR. LUIGI OLIVIERI ATTOR EYS United States Patent 3,162,986 METHGD AND APPARATUS FOR FEEDING AREAS-IVES Luigi Oiivieri, Pisa, Itaiy, assignor to Compagnie de Saint- Gobain, Neuiiiy-sur-Seine, 1 rance Filed Jan. '18, 1963, Ser. No. 252,374 Claims priority, appiication France Feb. 6, 1962 15 Claims. (Cl. 51-263) The present invention relates to feeding plate glass polishing tools with abrasive material. It consists of a feeding process and a device for the application of said process.

It is known that polishing tools are provided with a rubbing surface consisting of a felt material. The abrasive composed of an aqueous suspension of levigated Fe O to which a ferrous sulfate solution has been added is supplied at the point between the glass and the felt material. The levigated material and the sulfate are mixed in sulficiently large tanks equipped with agitators.

Considering the small amounts of abrasive that are to appear under the felts, the pipes carrying the abrasive would rapidly become clogged without an abundant flow of this abrasive revolving in a closed circuit from the tank, where the suspension is being formed, and returning thereto. Small amounts of the required abrasive are tapped at each tool or at each tool set at dilferent points of the circuit.

The process according to the invention consists in that only the suspension of levigated material is carried into a heavy discharge, closed circuit from which, at different points material is removed and directed toward the polishing tools, while the ferrous sulfate solution is added to the said tappings in adjustable quantities and strengths.

The application of this process results in an improvement of the quality of the polish combined with the fact that this quality is maintained at a uniform level, and a notable reduction in the consumption of levigated material. The material thus economized may amount to 25%.

Applicants works indicate that this improvement is probably due to the fact that, since the ferrous sulfate solution is no longer subjected to extended circulation, the time required from the moment of its mixture with the levigated abrasive material until its arrival at the polishing tools is too short to subject it to alteration.

Described below as a non-limiting example is a method for the application of the process according to the invention, as applied to continuous polishing of a strip of plate glass. It is illustrated by the figures of the annexed drawings, representing:

FIG. 1 is a schematic view of the supply of abrasive material;

FIG. 2 is a view, on an enlarged scale, of the device for feeding the levigated material, the ferrous sulfate and the feedwater and their mixture to their entry into the discharge pipes to the polishing tool; and

FIG. 3 is an end view taken along line 33 of FIG. 2.

In these figures, the strip of glass to be polished is schematically illustrated as the numeral 1 and 2-2' schematically show two polishing instruments of any conventional construction. The levigated abrasive material is prepared in tanks like those shown in 33', large enough for the preparation of appropriate quantities, said tanks being provided with rotary agitators 44 having arms such as 55'. The suspension of the levigated material prepared in the tanks is discharged by pumps 66' into a pipe system 77 and is fed back to the tanks 3-3, thus making uninterruptedly a number of closed cycles before the tanks 3-3 are empty. The tanks are provided with draining cocks 8-8.

The dissolving of the ferrous sulfate is carried out in a tank 9 provided with a rotary blade agitator 10. The solution is transferred by siphoning into a second tank 11 comprising a separator wall 12 for keeping impurities likely to be present in the solution away from the ferrous sulfate solution forcing pump 13. Drainage cocks 8a are provided on the floor of the tanks 9 and 11. These-lution delivered into a conduit 14 flows into a series of

tanks

15, 16 and 17 that are under pressure with respect to the tapping units 2-2'. The pump 13 discharges into the tank 15 which feeds t.e tank 16, thus avoiding swirling movements. Through the opening 20, the tank 17 is supplied with a solution of a given density. The levels in the tanks 16 and 17 are kept constant by electrical means, not shown. The sulfate solution flows through the

pipes

21, 22 to the tapping units 22'.

A water tank 23 makes it possible to supply the tank 17 through opening 29 in order to dilute the solution in that tank, and by means of the pipeline 24 the tapping points 2-2 can be furnished with additional amounts of water.

The tapping unit is shown in detail in FIGURES 2 and 3. The levigated abrasive material is tapped at 25, the ferrous sulfate at 26, and the water at 27. The discharges are controlled by any conventional adjustable tube clamping means such as Mohrs tweezers similar to those shown at 28 for controlling the rate of fluid flow in the tube. The levigated material is fed into an automatic feed regulator 29 of the open cyclone type. It prevents thick grains, likely to be present, from arriving on the strip of glass and, by swirling movements, like wise prevents thickening of the suspension. The latter is delivered in large amounts into the pipe 36 and in small amounts through pipe 311 into the column 33 up to the level 11. corresponding to a desired discharge rate. The suspension flows from column 30 through the outlet 31 into the container 39. The

pipes

33, 34 and 36 return the excess amount of the regulator 29 through the spout 32 and 32' to the tank 3-3. The ferrous sulfate tapped at 26 rises inside a column 37 to a level adjusted to be at the same elevation h. This solution flows out through an opening 38 and mingles with the levigated material in the container 3%. The mixture flows into funnels 4i) and 40 whence pipes 41 carry it to the polishing instruments. The discharges of levigated abrasive material and ferrous sulfate, which are in proportion at h, as well as their density, have been computed so that all that is required is to maintain the feeders for the columns holding the P6 0, suspension and the FeSO solution, respectively, at the same level in order to have a supply of constant density and containing at all times the same percentage of FeSO The feedwater supplies two

columns

42, 43 where it reaches a given level determined by Mohrs tweezers.

As many apparently widely different embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments.

What is claimed is:

1. An apparatus for feeding an abrasive mixture to glass polishing tools comprising means to maintain a predetermined amountof levigated material in a first container,

means to maintain a predetermined amount of iron sulfate solution in a second container, means to discharge levigated material from said first container, means to discharge the iron sulfate solution from said second container and means adjacent said polishing tool for receiving and mixing the discharge from said first and second containers and for feeding the said mixture to the polishing tool.

2. An apparatus as defined in claim 1 comprising means to maintain a predetermined amount of water in a third w container, means to discharge Water from said third container, and mixing said discharged Water With said mixture before it is fed to the polishing tool.

3. An apparatus for feeding an abrasive mixture to a glass polishing tool comprising a tank for a supply of a suspension of iron oxide in Water, a closed pipe circuit and pump for circulating said iron oxide suspension from and back to said tank, a tapping means in said closed pipe circuit, a first container in said tapping means, means to control the flow of said iron oxide suspension in said tapping means to maintain a predetermined level in said first container, a tank for holding a supply of iron sulfate solution, means for feeding the iron sulfate solution in said tank to a second container, means to control the feeding of said iron sulfate to maintain a predetermined level in said second container, means to discharge said iron sulfate solution from said second container, and means adjacent said polishing tool for receiving and mixing the discharges from said first and second containers and for feeding the said mixture to the polishing tool.

4. Apparatus as defined in claim 3 wherein the means for feeding said first and second containers comprises flexible tube members and said means to control said feeding comprises means to reduce the cross sectional area in said flexible tube members and thus reduce the flow of material therethrough.

5. Apparatus as defined in claim 3 comprising a supply of Water,'a third container operatively connected to said supply of water, means to control the flow in said water supply to maintain a predetermined level in said third container, means for discharging said Water from said third container, and means for mixing the Water discharged from said third container with said mixture before it is fed to the polishing tool.

6. Apparatus as defined in claim 5 wherein the discharges from said container is constant at a predetermined rate and said containers are maintained at said predetermined levels.

7. Apparatus as defined in claim 3 wherein said tapping means comprises a first tube from said closed pipe circuit to a constant level agitator tank, an overflow tube at the top of said agitator, a second tube from said agitator tank into said first container, and a third tube from said first container.

8. Apparatus as defined in claim 7 comprising means for receiving the discharges from the agitator overflow tube and said third tube and for directing said discharges into said tank'of the iron oxide.

9. An apparatus for feeding an abrasive mixture to a glass polishing tool comprising a closed pipe circuit, means to continuously circulate an iron oxide suspension in said closed pipe circuit, a tapping means in said closed pipe circuit, a first container of the cyclone type, means to introduce a flow of iron oxide suspension from said tapping means into said cyclone, means to continuously Withdraw excess iron oxide suspension and thick grains of iron oxide from said cyclone, means adjacent said polishing tool for receiving and mixing said iron oxide suspension with an iron sulfate solution, means to control the feed of said iron oxide suspension from said cyclone into said mixing means and means to control the feed of iron sulfate solution into said mixing means, and means for feeding said mixture to the polishing tool,

10. Apparatus as defined in claim 9 wherein the means to control the feed either of iron oxide suspension or of iron sulfate solution comprise a container, means to control the feeding of either said suspension or said solution to maintain a predetermined level either of suspension or solution in said container and means to discharge either said suspension or said solution into said mixing means.

11. Apparatus as defined in claim 9 comprising means for mixing a controlled fiow of water With said mixture before it is fed to the polishing tool.

12. Apparatus as defined in claim 9 comprising a supply of Water, a container operatively connected to said supply of Water, means to control the flow of Water from said supply into said container to maintain a predetermined level in said container, means for discharging said Water from said container into means adjacent the polishing tool wherein it is mixed with said mixture of iron oxide suspension and iron sulfate solution before it is fed to the polishing tool.

13. The method of feeding abrasive material to glass polishing tools comprising the steps of circulating a sus pension of levigated material in a closed pipe circuit, removing measured amounts of levigated material from said closed circuit, mixing said measured amount of levigated material with a predetermined amount of iron sulfate solution, and immediately feeding said mixture to said polishing tool.

14. The method of feeding abrasive material to glass polishing tools comprising the steps of constantly maintaining a measured supply of a suspension of iron oxide in Water while at the same time constantly discharging said iron oxide suspension at a predetermined rate, constantly maintaining a measured supply of iron sulfate solution While at the same time constantly discharging said iron sulfate at a predetermined rate, constantly mixing the discharges of iron oxide suspension and said iron sulfate solution and immediately feeding said mixture to said polishing tools.

15. An apparatus as defined in claim 3 wherein the iron sulfate solution is fed through a siphon from said iron sulfate supply tank into a second tank equipped with an impurity-retaining partition and with a pump feeding said solution into a third tank out of which said solution flows without whirling around into a fourth tank from which said solution is fed into said second container.

References Cited in the file of this patent UNITED STATES PATENTS 1,136,328 Golightly Apr. 20, 1915 1,556,753 Brown Oct. l3, 1925 1,587,526 Hitchcock June 8, 1926 1,740,005 Crowley Dec. 17, 1929 2,069,261 Monnet Feb. 2, 1937 2,191,962 Jones Feb. 27, 1940 2,646,655 Laverdisse July 28, 1953 2,780,038 laverdisse Feb. 5, 1957 2,873,563 Thompson Feb. 17, 1959 3,028,711 Campbell Apr. 10, 1962

Claims

1.AN APPARATUS FOR FEEDING AN ABRASIVE MIXTURE OF GLASS POLISHING TOOLS COMPRISING MEANS TO MAINTAIN A PREDETERMINED AMOUNT OF LEVIGATED MATERIAL IN A FIRST CONTAINER, MEANS TO MAINTAIN A PREDETERMINED AMOUNT OF IRON SULFATE SOLUTION IN A SECOND CONTAINER, MEANS TO DISCHARGE LEVIGATED MATERIAL FROM SAID FIRST CONTAINER, MEANS TO DISCHARGE THE IRON SULFATE SOLUTION FROM SAID SECOND CONTAINER AND MEANS ADJACENT SAID POLISHING TOOL FOR RECEIVING AND MIXING THE DISCHARGE FROM SAID FIRST AND SECOND CONTAINERS AND FOR FEEDING THE SAID MIXTURE TO THE POLISHING TOOL.