US3744776A

US3744776A - Device at cooling baths for tempering furnaces

Info

Publication number: US3744776A
Application number: US00176978A
Authority: US
Inventors: B Nyberg
Original assignee: SKF Industrial Trading and Development Co BV
Current assignee: SKF Industrial Trading and Development Co BV
Priority date: 1971-09-01
Filing date: 1971-09-01
Publication date: 1973-07-10
Anticipated expiration: 1990-07-10

Abstract

In a cooling bath arranged in connection to a tempering furnace, a shielded chamber being immersed in the bath, a smooth first conveyor running horizontally through said chamber, perforations in said conveyor being adjustable to coincide with corresponding perforations in the bottom of the chamber, reversible means for giving a cooling fluid contained in the bath an ever changing flow direction within said chamber, a second sloping conveyor provided with carrier means and adapted to bring the cooled work pieces up from the bath after passing the shielded chamber. By constantly changing the flow direction of the cooling fluid and by governing the rate of flow through the chamber by means of the adjustably arranged communications between the perforations in conveyor and chamber bottom it is possible to obtain a very uniform cooling.

Description

11 3,744,776 July 10, I973 1 DEVICE AT COOLING BATl-IS FOR TEMPERING FURNACES Bengt Johan Nyberg, Goteborg, Sweden SKF Industrial Trading and Development Company N.V., Amsterdam, Netherlands Filed: Sept. 1, 1971 Appl. No.: 176,978

lnventor:

Assignee:

US. Cl. 266/6 R, 148/144, 148/153, 266/4 A Int. Cl C2ld l/64 Field of Search 148/143, 144, 153; 266/4 A, 6 R, 6 S

References Cited UNITED STATES PATENTS 6/1943 Purnell 148/153 3,164,656 l/1965 lpsen 266/6 R 3,340,109 9/1967 Keough 148/153 FOREIGN PATENTS OR APPLICATIONS 53,325 5/1967 Poland 148/153 1,216,905 5/1966 Germany 148/143 Primary Examiner-Gerald A. Dost Attorney- Dexter N. Shaw, Eugene E. Renz,Jr. et al.

[57] ABSTRACT In a cooling bath arranged in connection to a tempering furnace, a shielded chamber being immersed in the bath, a smooth first conveyor running horizontally through said chamber, perforations in said conveyor being adjustable to coincide with corresponding perforations in the bottom of the chamber, reversible means for giving a cooling fluid contained in the bath an ever changing flow direction within said chamber, a second sloping conveyor provided with carrier means and adapted to bring the cooled work pieces up from the bath after passing the shielded chamber. By constantly changing the flow direction of the cooling fluid and by governing the rate of flow through the chamber by means of the adjustably arranged communications be tween the perforations in conveyor and chamber bottom it is possible to obtain a very uniform cooling.

3 Claims, 2 Drawing Figures PATENTEI] JUL 1 0 I975 DEVICE AT COOLING BATHS FOR TEMPERING FURNACES BACKGROUND OF THE INVENTION Annular work pieces, e.g., such intended for parts of rolling bearings of different kinds, are upon final machining tempered in such a manner that they are heated in a furnace and thereupon are conveyed through a cooling bath.

The normal manner in which this is carried out is that the work pieces are transferred from the furnace via a chute feeder to an endless conveyer belt having a receiving portion in the bath and one portion which projects upwards out of this in order to deliver the cooled work pieces. The cooling liquid, the oil, is always kept in motion by aid of for instance one or more pumps, propeller devices or the like, which are immersed in the bath.

It has, however, shown that the work pieces are somewhat deformed, due to the one-sided directed oil flow, i.e., the cooling which they are exposed to. Due

This conicity may amount to 0.05 0.15 mm at rings having a diameter, of 75 100 mm. Rings having nonsymmetrical material section, i.e., outer rings for taper roller bearings, will become more exposed to such errors when the thinwalled side of the ring arbitrarily is turned downwards. Rings having a nonsymmetrical material section in themselves have a tendency of becoming conical, due to the fact that the forming of martensite takes place non-uniformly in the varying material section but the error is increased if the thin portion is turned to a one-sided directed cooling fluid flow. The non-uniform cooling furthermore causes a certain outof-roundness (ovality).

In order to be able to get the work pieces up from the bath, the belt generally is provided with carrier means. This, however, easily may cause that the work pieces are gathered already on the primary cooling portion of the belt which causes an impaired cooling of the separate work pieces with out-of-roundness as a result.

SUMMARY OF THE INVENTION The aim of the present invention is to eliminate the above-mentioned drawbacks, and this is effected thereby that the conveyor belt is adapted to pass through a shielded unit which is immersed in the bath and in which the flow of the cooling fluid by means of suitably designed mechanical means is brought constantly to change direction.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings attached there are shown an embodiment as an example suited for the cooling bath after a furnace for tempering rings for rolling bearings.

FIG. 1 is a section through the bath with a portion of the conveyor belt; and

FIG. 2 is a cut along line 2-2 in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The annular work pieces are transferred from the tempering furnace 10 which is not shown in detail, through a chute feeder 11 to a cooling bath which is generally numbered 12. This bath is formed as a large tank comprising a considerable quantity of cooling fluid. In thebath there is entirely immersed a shielded unit, the flush chamber 13, which principally is designed as a box provided with a horizontal throughpassage 14. In the bath there is arranged a conveyor belt 15 which runs over rollers 16 being arranged in a suitable way and being driven in a manner which is not further shown. The very belt is provided with holes or is perforated and extends with a first receiving portion 17 in a horizontal direction through the passage 14, outside this to the opening of the feeder 11. The conveyor belt 15 comprises a rising portion 18 by aid of which the work pieces are conveyed up from the bath after the treatment is finished.

The

wall portion

19 and 20 respectively of the flush chamber 13, which are parallel with the receiving portion 17 of the belt are perforated and adapted to cooperate with

plates

21 and 22 which also are perforated and which by means of a lever 23 may be moved in the plane of the wallportions in such a manner that the perforations in the wall portions and the plates respectively may be brought to coincide more or less, thereby to govern the flow velocity of the fluid.

In the flush chamber 13 there are mounted two propellers 24 which are driven by one motor 25 each. The propellers are provided with pivotable blades and by means of pneumatical maneuvering and a time relay the adjustment of the propeller blades may be changed at even time intervals, i.e., each fifth second. The cooling fluid thereby is pressed through the passage and the belt at right angles against the direction of movement of this, alternately from the upper side and downwards and from the lower side and upwards, respectively.

The work pieces which pass down through the feeder l l'are distributed over the first portion of the conveyor belt and are slowly conveyed through the shielded unit. The work pieces thereby will be exposed to a fluid flow which constantly changes direction and its temperature may be kept at a desirable value thereby that the flow path is settled in order to eliminate the risk for conicity as far as possible.

A conveyor belt which is entirely smooth is not able to transfer the work pieces up from the bath and in order to prevent that,the work pieces are gathered by carrier members already in the first part of the conveyor belt, the very belt is designed without such carrier members. Parallel to the portion 18 of the conveyor belt 18 which-projects from the bath there is therefore arranged a second conveyor belt 26 which is provided with carrier members 27 adapted to catch the work pieces at the end of the horizontal path 17 of the belt and which members carry the work pieces up along the rising portion 18.

Cooling fluid is lead vertically through the passage 14 upwards or downwards respectively and, if so desired, it is of course possible to arrange adjustable openings in the outer walls of the flush chamber in order to allow introduction and discharge respectively of cooling fluid to the interior of this. The number of propellers must be adapted to the capacity of the cooling bath and other means for reversing the working direction of the propellers such as phase inverters at the motors can also be used.

What I claim is:

l. A device at cooling baths for tempering furnaces intended for treatment of preferably annular work pieces which from the furnace are transferred to a conveyor belt being immersed in a cooling bath and through which belt a cooling fluid may be brought to flow, in which the conveyor belt is adapted to pass through a shielded unit, the flush chamber, which is immersed in the bath and in which the flow of the cooling fluid is brought constantly to change its direction by means of suitably designed mechanical means.

2. A device according to claim 1 in which the conveyor belt extends through a horizontal passage in the flush chamber, wherein wall portions of the passage being parallel with the belt are perforated and at least that one of these are adapted to cooperate with an also perforated plate which is movable in the plane of the members.

Patent NO. I Dated l0,

Inventor(s) Bengt Johan Nyberg It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet insert I30] Foreign Application Priority Data September 2, 1970 Sweden 11905/70 Signed and sealed this 29th day of January 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents ORM PC4050 $59) 2 USCOMM-DC 60376-P69 UIS. GOVERNHENT PIJNTING OFFICE! O 3$-33. a

Claims

1. A device at cooling baths for tempering furnaces intended for treatment of preferably annular work pieces which from the furnace are transferred to a conveyor belt being immersed in a cooling bath and through which belt a cooling fluid may be brought to flow, in which the conveyor belt is adapted to pass through a shielded unit, the flush chamber, which is immersed in the bath and in which the flow of the cooling fluid is brought constantly to change its direction by means of suitably designed mechanical means.

2. A device according to claim 1 in which the conveyor belt extends through a horizontal passage in the flush chamber, wherein wall portions of the passage being parallel with the belt are perforated and at least that one of these are adapted to cooperate with an also perforated plate which is movable in the plane of the wall portions in order to adjust the area of flow.

3. A device according to claim 1, wherein the conveyor belt is designed as a smooth belt adapted to project up from the bath after the flush chamber and that the rising portion of the conveyor belt is intended to cooperate with a second conveyor belt which is arranged parallel with the first one and is provided with carrier members.