US3721334A

US3721334A - Rocking hearth furnace

Info

Publication number: US3721334A
Application number: US00134225A
Authority: US
Inventors: A Jarema
Original assignee: SOLAR BASIC IND Inc
Current assignee: SOLAR BASIC IND Inc
Priority date: 1971-04-15
Filing date: 1971-04-15
Publication date: 1973-03-20
Anticipated expiration: 1990-03-20

Abstract

A hearth in a heat processing furnace has a plurality of angularly disposed baffles arranged in alternating overlapping relationship extending longitudinally on the upper surface thereof. The hearth is mounted for oscillating movement about a longitudinal axis so that periodic rocking of the hearth will advance articles along its upper surface by the sliding or rolling of the articles back and forth between alternate baffles.

Description

M lMarch 20, 1973 ilnited States Patent 1191 Jarema [5 1 ROCKING HEARTH FURNACE 1,799,956 5 1931 Cope..1...1...........................263/2lC [75] Inventor: Alexander J. Jaremakiver Forest 2,916,276 12/1959 Coneetal......................... ...263/6R Primary ExaminerJohn J. Camby Att0meySmythe & Moore [73] Assignee: Solar Basic Industries Inc., Milwau- [57] ABSTRACT A hearth in a heat processing furnace has a plurality of angularly disposed baffles arranged in alternating kee, Wis.

[22] Filed: April 15, 1971 [21] Appl.No.: 134,225

overlapping relationship extending longitudinally on the upper surface thereof. The hearth is mounted for oscillating movement about a longitudinal axis so that [52] U.S.Cl...............................198/2l8,432/l34 eriodic rocking of the hearth will advance articles 0. MC /1 2 b1 R FM 3 6 m .mh "C r a e "S 1 m d t d l ME .1] 00 55 ll along its upper surface by the sliding or rolling of the articles back and forth between alternate baffles.

[56] References Cited UNITED STATES PATENTS 5 Claims, 8 Drawing Figures 1,405,762 2/1922 Curtis.................................263/2lC PATENTEDmzom "3 1, 34

SHEET 2 [IF 2 INVENTOR ALEXANDER J. JAREMA ATTORNEY 5' ROCKING HEARTH FURNACE A heat processing furnace adapted for continuous operation is provided with a form of a conveyor for advancing the articles to be treated through the furnace. One such form of structure essentially comprises a hearth upon which the articles are supported as they are subjected to heatingfrom electric heating elements or burners disposed adjacent the hearth. A conveyor is then employed to move the articles along the hearth so that each article is exposed to the heat source for a predetermined duration of time. It has been proposed in the past to provide such a furnace with a reciprocating hearth which advances the articles as it supports the articles during the heating process. Other such furnaces have been provided with shaking or vibrating hearths which also function to advance the articles being supported thereon.

One of the objects of the present invention is to provide an improved conveyor heat processing furnace.

Another of the objects of the present invention is to provide a heat processing furnace through which articles upon a hearth are advanced by periodic rocking of the hearth.

Another object of the present invention is to provide a conveyor heat treating furnace which is particularly adapted to ultra-high temperature processing.

According to one aspect of the present invention, a heat processing furnace may comprise a hearth therein and means for oscillating the hearth. A plurality of an-' gularly disposed baffles are arranged in alternating overlapping relationship on the upper surface of the hearth along a direction parallel to the axis of oscillation. Rocking or oscillating of the hearth about the axis of oscillation will cause the articles to roll or slide back and forth between alternate baffles so that the articles are positively and uniformly advanced along the hearth in a direction parallel to the axis of oscillation.

The baffles are angled toward the entrance or supply end of the hearth with their inner ends overlapping each other and their outer ends bounded by longitudinally extending retaining lips or walls.

A second set of similarly disposed baffles may be positioned adjacent the first set of baffles but angled in the opposite direction so as to define a direction of advance of the articles which is counterflow to the firs direction of movement.

Other objects, advantages and features of the present invention will becomeapparent from the accompany ing description and drawings, which are merely exemplary.

In the drawings:

FIG. 1 is a vertical sectional view taken through the longitudinal axis of a heat processing furnace incorporating the present invention;

FIG. 2 is an end elevational sectional view of the furnace shown in FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2 and showing the upper surface of the hearth in plan view;

FIGS. 4A and 4B are fragmentary top and end views of the hearth when rocked in one direction;

FIGS. 5A and 5B are similar to FIGS. 4A and 4B when the hearth is rocked in the opposite direction; and

FIG. 6 is a top plan view of a modification of the hearth of the present invention.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views, a specific embodiment of the present invention will be described in detail.

FIG. 1 illustrates generally at 10 a heat processing furnace according to the present invention which is provided with a passage 11 therethrough passing through a chamber 12 in which are mounted a plurality of heating elements 13 which may be electric or also may be gas or oil burners.

A hearth 14 having an upper surface 15 is mounted for oscillatory movement about a longitudinal axis 16 by means of shafts l7 and 17a joumaled in bearing blocks 18 and 18a. The shaft 17 is connected to a variable speed tilting or oscillating mechanism which is not shown in the drawings.

The upper surface 15 of the hearth is provided with a plurality of angularly disposed baffles 20 which are arranged in alternating overlapping relationship along a direction parallel to the axis of oscillation as may be best seen in FIG. 3. The baffles 20 form a substantially herringbone pattern with their inner ends 21 extending beyond the central axis of the upper surface of the hearth. The central axis in this embodiment is positioned in the same vertical plane as the oscillatory axis 16 when the hearth is in its horizontal position.

The outer ends 22 of the baffles

abut retainer edges

23 and 24 which extend longitudinally on the upper surface of the hearth.

One end of the hearth extends outwardly from the furnace to define a loading area as indicated at 25. This area provides a space upon which the articles to be heat treated are introduced. A suitable metering device known in the art may be positioned at the front or loading area of the hearth to regulate the flow of articles being introduced upon the hearth. The meter is preferably of a type which will not overload the furnace hearth.

At the other or discharged end of the hearth, indicated at 26, there is provided a receiving pan 27.

The hearth plates or supporting surfaces of the hearth are cast of heat resisting alloy or molded of alumina or other ceramic with the retaining edges and herringbone baffles. At any given moment, the hearth is only sparsely loaded with articles, with the ultimate rate of feed being determined by the metering device loading the hearth at the front end 25. The slow continuous rocking of the hearth causes the articles to alternatively shift from side to side between the alternate baffles. The articles are thus advanced at a uniform rate toward the discharge end 26 of the hearth.

The articles which can be processed may include but are not limited to springs, bearing races, chain links, chain saw teeth, concrete drive studs, nuts, bolts, Allen head wrenches, shoe shanks, textile needles, office machine stampings, and a wide range of similar articles.

The conveying heat processing furnace according to the present invention is particularly adaptable to ultrahigh temperature applications since the supporting structure for the hearth can be positioned outside of the furnace and, thus, need not be subject to the high temperatures encountered within the furnace. Further, the mechanism for oscillating the hearth to advance the articles to the furnace is also positioned outwardly from the furnace. Thus, the actual hearth can be molded of any high temperature refractory so that the upper limit of the heat processing temperature is defined only by the refractory material of the hearth and furnace and of the heating source.

FIGS. 4A, 4B and 5A, 5B show the path of travel of articles as the hearth is oscillated.

In FIG. 6 there is shown a modification of the present invention wherein a second hearth with angularly disposed baffles is positioned adjacent to the first but with the baffles of the second hearth angled in the opposite direction. Thus, the oscillating of the hearths will cause the articles thereon to be conveyed in a U-shaped path as indicated by the arrow 30. With this arrangement, the articles may be both supplied and discharged at the same end of the furnace at 31. The other ends of the hearths are provided with a fiat area 32 by means of which the articles are shifted from one hearth to the other.

It will be understood that changes in various details of construction and arrangement of parts may be made without departing from the spirit of the invention except as defined in the appended claims.

What is claimed is:

1. In a heat processing furnace, the combination including a hearth within the furnace, means for oscillat-' ing said hearth about an axis thereof, a plurality of angularly disposed baffles having their inner ends arranged in alternating overlapping relationship on the upper surface of said hearth along a direction parallel to the axis of rotation whereby rocking of said hearth causes the articles to travel back and forth between alternate baffles so that the articles are intermittently advanced along the hearth.

2. In a heat processing furnace as claimed in claim 1 and further comprising longitudinal retaining means on said hearth upper surface along the outer ends of said baffles.

3. In a heat processing furnace as claimed in claim 1 wherein said baffles are angled toward the end of the hearth at which articles are supplied.

4. In a heat processing furnace as claimed in claim 1 wherein the inner ends of said baffles extend beyond the center line of the upper surface of the hearth.

5. In a heat processing furnace as claimed in claim 1 and comprising a second hearth similarly disposed and adjacent to the first hearth but having baffles angled in the opposite direction to define a second direction of movement opposite to the first direction of movement so that articles are introduced at one end of one hearth, advanced in counterflow fashion, and discharged at the same end of the furnace.

Claims

1. In a heat processing furnace, the combination including a hearth within the furnace, means for oscillating said hearth about an axis thereof, a plurality of angularly disposed baffles having their inner ends arranged in alternating overlapping relationship on the upper surface of said hearth along a direction parallel to the axis of rotation whereby rocking of said hearth causes the articles to travel back and forth between alternate baffles so that the articles are intermittently advanced along the hearth.