US2756980A - Lamp making machine and oven therefor - Google Patents

Description

July 31, 1956 a. E. OTT

LAMP MAKING MACHINE AND OVEN THEREFOR 2 Sheets-Sheet 1 Filed April 1. 1953 II I 0 5 H & \L 3 0 6 L f I 6 //T/ O 2 I 5 v% n J o 9 4 Yo 2 3 I ll\ /7 x 4 M/ lnvenoor; George E. 01st,,

(1 His Att, ney

July 31, 1956 Filed April 1, 1953 G. E. OTT

LAMP MAKING MACHINE AND OVEN THEREFOR 2 Sheets-Sheet 2 Inventor.- George E. 011/0, Y WC His Attorney LAMP MAKING MACHINE AND OVEN THEREFOR George E. Ott, Willoughby, Ohio, assignor to General Electric Company, a corporation of New York Application April 1, 1953, Serial No. 346,190

Claims. (Cl. 2637) My invention relates to automatic machines for manufacturing electric lamps and discharge devices. More particularly, my invention relates to an indexing form of an automatic machine having in combination therewith an oven for heating lamps and discharge devices at a succession of work stations.

The indexing type of machine, which advances the article to be manufactured to each of a succession of work stations in turn is widely used for the manufacture of lamps and discharge devices because of the ease with which various manufacturing mechanisms and devices can be incorporated therein and because of the rapidity with which such apparatus is capable of operating. When such machines have heating apparatus in combination therewith, as for instance when it is required to heat the lamps or discharge devices in the course of exhausting them or to condition a coating on the envelopes of said lamps or discharge devices, the proper control and distribution of heat is difficult to achieve except by the common types of radiant electric heating apparatus.

One object of my invention is to reduce the cost of heating lamps and discharge devices in the indexing or carrier type machine by providing in association therewith an oven in which air is heated by a burner using either gas or fuel oil, and in which the heated air is circulated through the oven at certain of the work stations thereabout.

Another object of my invention is to provide such an oven so constructed and arranged as to heat relatively long tubular lamps and similar devices uniformly and speedily to a relatively high temperature. I have found that the vertically disposed lamps are heated much more uniformly by directing the heated air stream horizontally, rather than vertically, across the lamps.

Another object of my invention is to provide an air circulating type of oven at a succession of work stations about a work carrying turret of a machine for making lamps and discharge devices, which is so constructed as to circulate the heated air horizontally in a manner to prevent appreciable loss of heated air at the entrance and exit openings therein so as to eliminate the need for doors at said openings.

Another object is to provide a novel structure wherein the roof and sidewalls of the oven are suspended from the top so that any expansion is in a downward direction whereby shoeplate members, carried by the machine heads and which seal the top of the oven, are always in contact with their track.

Other objects and features of my invention will appear from the following detailed description of a species thereof and from the drawings.

In the drawings,

Fig. 1 is a plan view of approximately one half of an exhaust machine for fluorescent lamps, said view being modified by the breaking away of top sections of said machine including a series of lamp holding heads and the top of the oven.

Fig. 2 is a diagrammatic perspective view. showing essential elements of the oven.

Fig. 3 is a vertical section through a peripheral portion of the exhaust machine and the adjacent oven portion nited States Patent O 2,756,980 Patented July 31, 1956 along a vertical plane indicated by the dot-dash line 3--3 in Fig. 1.

In general, the oven illustrated in the drawings comprises an interior heating area or chamber C into which projects a burner 25 and its heat-distributing tube or muflle 24. The muflie is designed to spread the heat from the burner evenly from top to bottom of the heating chamber C. This is an important feature in attaining uniformity in temperature of the air stream; it is not attained by a blower (such as shown at 28) alone. On one side of the chamber C is' a blower 28 mounted approximately midway relative to the over-all height of the oven and with its intake or suction side 42 projecting into the chamber C. The blower 28 picks up the heated air and projects it into a distributing duct 29 at a high velocity, for example 9000 cubic feet per minute. The duct 29, by virtue of its shape and the use of adjustable vanes 43, is designed to spread the heated air vertically so it will cover the entire height of the oven. At the end of the duct 29 the air stream is made to turn approximately by means of a suitable bafiie 44. Adjacent this turn there is located the exit opening 11 for passage of the lamps 4 from the oven. The construction is such as to cause the heated air to pass across the exit 11 at a high speed and form an air curtain to prevent the escape of heat. The heated stream of air then continues to flow through a channel 8 contra to the movement of the lamps around the machine for the desired distance after which it is again caused to turn 120 across the entrance opening 5 and back into the heating chamber C where it is reheated and recirculated through the oven. In order to further assure against escape of heat from the entrance opening 5, I preferably provide a second air curtain across that opening by means of a vertical pipe 35 which is supplied with low pressure air, say 3.5 pounds per square inch, and which has a series of small holes arranged to provide the air curtain. This construction eliminates the necessity of providing doors across the entrance and exit openings.

The oven is located to span a succession of work stations about a machine for exhausting elongated tubular lamps and conditioning a coating of fluorescent material on the inner surface thereof. The oven is arranged below lamp carrying heads 1 of the exhaust machine, which heads are regularly spaced about the periphery of a turret 2 on a center column 3. The exhaust machine may be of the type shown in the United States Patent 2,247,513, Marshaus, dated July 1, 1941, which patent is assigned to the assignee of the present invention, and which provides for certain operations in the manufacture of fluorescent lamps to take place, during the course of which said heads 1 are indexed in a counter-clockwise direction about the machine by movements of the turret or carrier 2. An elongated tubular fluorescent lamp 4 is retained in a vertical position below each head 1 and is carried into the opening 5 in the end of the oven while almost all of the head 1 remains above said oven and maintains a connection to the said lamp 4 through means extending through a slit 7 (Fig. 3) in the top of said oven 6. The normal indexing motions of the turret 2 advance the lamp 4 through the length of the arcuate passageway 8 formed by the vertical outer wall 9 and the inner thin metallic wall 10 of the oven 6 while the head 1 is advanced to a succession of work stations of the machine. The lamp 4 passes from the oven through opening 11 at the end of the passageway 8 therein.

Each lamp 4 is connected to a head 1 by an exhaust tube 12 extending upward from the lamp into the compression rubber 13 of the exhaust system, and is supported by the gripping action of jaws 14, 15 and 16 in engagement with an upper portion of the tubular envelope 17 thereof. The jaws 14, 15 and 16 are mounted upon stationary and movable rods 18 and 19 extending downward from the main portion of the head 1 represented by the body 20 which also supports the exhaust rubber i3, and are arranged in this particular instance to precede the lamp 4 as it enters the opening in the oven 6. At that time, the metal shoeplate 21 in association with the head 1 also slides onto the track rails 22 on the top of the oven 6 and closes off the slit 7 therebetween accommodating the exhaust tube 12 and the rods 18 and 19.

The entrance of the lamps 4* into the passageway a; in the oven 6 immediately subjects them to the heated air constantly being circulated therethrough and very soon thereafter advances the lamps into the main air stream flowing in a clockwise direction about the machine and therefore contra to the direction of movement of the lamps. The flow of the heated air at the end of the passageway 8 adjacent the opening 5 in the oven 6 is sharply diverted laterally around the end of the inner wall it? thereof and along the outer wall 23 of the heating chamber. The continued circulation of the air stream carries it into wiping relation to the cylindrical chamber or mufiie 24 which is located in an upright position at a point spaced from the entrance opening 5 at the end of the oven 6. While in contact with the muffle 24 the air stream is heated by the gas flame directed into the open upper end thereof through the orifice block 25 of a burner mounted on the top 26 of the oven. The air stream also picks up the burning gases emerging from the openings 27 in the opposite side of the rnuflle from that impinged upon by said air stream. The arrangement of openings 27 in the muflle assists in providing the proper heat distribution therealong so that the air stream is heated quite uniformly by the time it is withdrawn from about the space around the muffle 24.

The heated air is pulled from about the muffle 24 by the blower 23 which directs it through the duct 29 which in turn spreads it vertically to the full height of the passage 8 of the oven 6 and causes it to enter the passageway 8 therein at a point adjacent the exit opening 11. The centrifugal type blower 28, which is operated by an electric motor (not shown) through the belts 3t) extending from the pulley 31 on the blower shaft 32, is the source of motion for the air circulation system which provides for the heated air to pass through the passage 6 and then be recirculated through a close circuit including the heating chamber C, said blower 28 and the duct 29. The closed air circulation. system provides for the air about the cooler lamps 4 adjacent the entrance opening 5 to be drawn from the passageway 8 to the heating chamber C for reheating, at the same time heated ir from about the muffle 24 is forced into the opposite end of the passage 6 adjacent the opening 11. Vertically extending deflectors 33 and 34 are mounted upon the end of the wall 9 of the oven to cause the air stream to be deflected away from the opening 5 so that little air escapes therefrom.

Inasmuch as any loss of heated air from the opening is objectionable because of the resulting discomfort to operators of the machine, means are provided for defleeting the heated air by jets of air directed across said opening 5 from the low pressure air manifold 35. One set of openings 36 along the length of the manifold 35 directs jets of air into the opening 5 at a very oblique angle so that an area of greater than atmospheric pressure is developed at the mouth of the opening 5 whereas a second set of openings 37 along said manifold 35 directs jets of air across said mouth of said opening 5 so that heated air passing beyond the opening 5 is blown behind the shield 38 and directed away from the adjacent portion of the exhaust machine.

The cylindrical tube or muffle 24 is mounted in an upright position upon legs resting upon the bottom 39 of the oven and is heated by the flames introduced into the upper end by a burner in part represented by the block 25 (Fig. 3) in the roof of the oven and directing said flames down against the closed bottom 49 of the muffle. In certain instances where the temperature of the circulated air must be so high as to normally cause the muffle 24 to deteriorate rapidly, said muffle can be protected by providing a relatively thick layer of a refractory cement over its inside surface.

A low wall 41 of fire brick is also provided between the oven wall 10 and the adjacent face of the blower 28 to cause the air emerging from the lower portion of the passage 6 to circulate up to heating relation with the muffle 24 before entering the intake opening 42 of said blower 28.

Since it is desirable that the lamps 4 be heated both as rapidly and uniformly as possible a high rate of circulation of the air is preferred and consequently a hig capacity blower 28 is provided. The blower 28, which is shown in a machine combination suited to the manufacture of the common forty-watt four-foot-long fluorescent lamps, draws the heated air from around the furnace 24 at the rate of 9,000 cu. ft. per min. and is of a construction to permit it to operate with air at 650 to 900 degree C. The blower 28 is completely enclosed, except for the drive shaft 32, within the heavily insulated walls of the oven and is arranged slightly above the vertical center of the oven 6 so that it tends to automatically direct more air in the top of the oven 6 as is required to heat the jaws 14, 15 and 16 of the lamp holding means. The heated air discharged by the blower 28 passes into the small end of the distribution duct 2) which is also completely contained within the walls of the oven, and, in the course of its movement therethrough, is directed suitably over the full vertical extent of the opposite end of the duct 29 by means of adjustable deflectors 43. The end of the duct 29 spreads to the full height of the passage 8 and directs the heated air into a curved pocket 4 in the end of the oven 6 in such a manner as to cause it to sweep into the passageway t; contra to the movement of the lamps 4 therein. This manner of directing the heated air into the passage 8 reduces the air pressure at the opening 11 to substantially atmospheric pressure so that little heated air is lost to the atmosphere through said opening 11.

A contributing factor to the proper pressure of the air within the passageway 8 and, of course, the escape of air from the oven 6 generally, is the flue 45 at the top of the end of the duct 29 in that said flue 45 draws olf suflicient air to cause the oven 6 to be maintained at or slightly below atmospheric pressure. The due 45 also serves to permit the products of combustion of the burning gases introduced into the air stream by the burner 25 to escape. A movement of hot air at a rate of 200 ft. per min. passes through the length of the passage 8 in the example outlined above with the result that the lamps 4 are brought up to the elevated temperature of the air in less than half their travel through the said passage and are maintained at their elevated temperature of said hot air for the remainder of the travel.

The high temperature of the air within the oven 6 requires that special means be provided to insulate pro vide for the expansion of the various parts thereof. As shown, the insulation 46 is comprised of relatively large sheets of expanded mica rock bound together with a suitable hinder or any of the well known products for this purpose. In every instance the insulation 4-6 is attached to a sheet metal outer skin and is mounted in sections in the same manner as said skin. The top 26 and sides 23, 47 and 48 of the oven are bound together in a single unit by means of outwardly extending flanges 49 which are bolted together and are supported by a frame 59 (only partially shown) of angle iron in engagement with the top 26. Support is provided this assembly by legs 51 attached only to the frame 50 and extending downward at spaced relation to the sides of the heating .apparatus so as to be out of the heat of the air stream and said sides. This manner of support causes all expansion of the heating apparatus in a vertical direction to be downward and maintains the top of the oven at essentially the same relation to the heads 1 of the exhaust machine at all times.

The side 9 of the oven under the turret 2 is also mounted in essentially the same manner by means of angle pieces 52 welded to top portions thereof and bolted to projections 53 on support brackets 54 on the stationary frame 55 of said exhaust machine. Other angle pieces 56 attached to lower portions of the side'9 of the oven are slidable along the shanks of bolts 57 attached to other projections 58 on said brackets 54 and hold said side 9 in its proper horizontal position while allowing it to expand freely in a vertical direction.

The bottom 39 of the oven, on the other hand, is independently mounted upon the blocks 59 carried by the bed plate 60 of the exhaust machine and other blocks (not shown) resting on the floor (also not shown). Because of the manner of mounting the bottom 39 of the oven, said bottom 39 does not follow the expansion of the sides 9, 23, 47 and 48 and a slip joint like'that shown at 61 is provided at the junction therebetween to prevent leakage of air at said junction. A similar slip joint comprised of a U-shaped strip 62 attached to the bottom 39 and engaging the lower edge of the entirely metal wall holds the lower end of said wall 10 in place.

While I have described the preferred embodiment of my invention, I do not wish to be limited to the exact structure shown as it will be understood that many modifications of the precise manner by which my invention is carried into effect, as well as the apparatus in which it is used, may be made without departing from the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with a machine of the class described comprising a carrier having thereon a series of heads for holding lamps and advancing them along a horizontal path of movement, of an oven located along said path and having therein vertical walls defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, said oven including a heating chamber adjacent and in communication with one vertically extending end of said passageway and means to heat air substantially uniformly within said chamber, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the other vertically extending end of said passageway to connect said blower, duct, passageway and heating chamber in a closed circuit within the oven for horizontal flow of heated air through said passageway.

2. The combination with a machine of the class described comprising a carrier having thereon a series of heads for'holding lamps and advancing them along a horizontal path of movement, of an oven located along said path and having therein vertical walls defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, said oven including a heating chamber adjacent and in communication with one vertically extending end of said passageway and means to heat air substantially uniformly within said chamber and comprising a vertically disposed tubular mufile member and a burner arranged to direct a flame into an end of said mufiie member, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the other vertically extending 6 end of said passageway to connect said blower, duct, passageway and heating chamber in a closed circuit within the oven for horizontal flow of heated air through said passageway.

3. The combination with a machine of the class described comprising a carrier having thereon a series of heads for holding lamps and advancing them along a horizontal path of movement, of an oven located along said path, and having therein vertical walls defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, said oven including a heating chamber adjacent and in communication with one vertically extending end of said passageway and means to heat air substantially uniformly within said chamber and comprising a vertically disposed tubular mufile member closed at its bottom and having openings along the side thereof facing away from the said one end of said passageway and a burner in the roof of the oven arranged to direct a flame downward into the open upper end of said muffle member, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the other vertically extending end of said passageway to connect said blower, duct, passageway and heating chamber in a closed circuit within the oven for horizontal flow of heated air through said passageway.

4. The combination with a machine of the class described comprising a carrier having thereon a series of heads for holding lamps and advancing them along a horizontal path of movement, of an oven located along said path and having therein vertical walls defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, said oven including a heating chamber adjacent and in communication with one vertically extending end of said passageway and means to heat air substantially uniformly within said chamber, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the other vertically extending end of said passageway to connect said blower, duct, passageway and heating chamber in a closed circuit within the oven for horizontal flow of heated air through said passageway, and a flue in said duct at a point adjacent its junction with the said other end of said passageway.

5. The combination with a machine of the class described comprising a carrier having thereon a series of heads for holding lamps and advancing them along a horizontal path of movement, of an oven located along said path and having therein vertical walls defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, said oven including a heating chamber adjacent and in communication with one vertically extending end of said passageway and means to heat air substantially uniformly within said chamber, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the other vertically extending end of said passageway at an acute angle thereto to connect said blower, duct, passageway and heating chamber in a closed circuit within the oven for horizontal flow of heated air through said passageway, and means defining a concave pocket at the far end of said duct arranged to sharply divert the flow of air from said duct into said passageway and across the adjacent opening at a high speed to form an air curtain across said opening and prevent substantial escape of heated air there from. I

6. The combination with a machine of the class described comprising a carrier having thereon a series of heads for holding lamps and advancing them along a horizontal path of movement, of an oven located along said path and having therein vertical walls defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, said oven including a heating chamber adjacent and in communication with one vertically extending end of said passageway and means to heat air substantially uniformly within said chamber, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the other vertically extending end of said passageway at an acute angle thereto to connect said blower, duct, passageway and heating chamber in a closed circuit within the oven for horizontal flow of heated air through said passagewa and means defining a concave pocket at the far end of said duct arranged to sharply divert the flow of air from said duct into said passageway and across the adjacent opening at a hi h speed to form an air curtain across said opening and prevent substantial escape of heated air therefrom, and deflector members in the said one end of said passageway adjacent the said opening thereat and arranged to deflect the air across said opening to minimize escape of heated air therefrom.

7. The combination with a machine of the class described comprising a carrier having thereon a series of heads for holding elongated tubular lamps vertically depending therefrom and for advancing them along a horizontal path of movement, of an oven including side walls and a roof and a floor with means defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, said oven including therewithin a heating chamber in communication with one vertically extending end of said passageway and means to heat air substantially uniformly within said chamber, a blower having its intake side communicating with said heating chamber, a duct leading from the outlet side of said blower to the other vertically extending end of said passageway to connect said blower, duct, passageway and heating chamber in a closed circuit within the oven for horizontal flow of heated air through said passageway, the roof of said oven having a slit therein co-extensive with the said passageway therethrough to accommodate portions of said heads, shoeplate means on said heads in sliding engagement with the walls of said slit to seal it off, and support means suspending the roof and side walls of the oven from its top independently of its floor to thereby confine expansion of the oven to a downward direction and maintain the seal between said shocplate means and the walls of said slit,

8. The combination with a machine of the class described comprising a carrier having thereon a series of heads for holding elongated tubular lamps vertically depending therefrom and for advancing them along a horizontal path of movement, of an oven including side walls and a roof and a floor with means defining a horizontal passageway therethrough vertically aligned with the path of movement of said heads and having vertically extending openings at the horizontally opposite ends of said passageway to accommodate said lamps, the roof of said oven having a slit therein co-extensive with the said passageway therethrough to accommodate portions of said heads, shoeplate means on said heads in sliding engagement with the walls of said slit to seal it off, and support means suspending th roof and side walls of the oven from its top independently of its floor to thereby confine expansion of the oven to a downward direction and maintain the seal between said shoeplate means and the walls of said slit.

9. The combination with a machine of the class described comprising a turret having at the periphery thereof a series of heads for holding elongated tubular lamps vertically depending therefrom and for advancing them along an arcuate path of movement, of an oven including sid walls and a roof and a floor, one of said side walls being arcuate and co-extensive with a portion of the said path of movement of the lamps, a supplementary arcuate wall member of sheet metal located within said oven concentric with said arcuate side wall and spaced therefrom to define therebetween a horizontal passageway enclosing said portion of the said path of movement of the lamps, said supplementary wall member extending vertically to the roof and floor of the oven but terminating short of the side walls thereof to leave vertically extending end openings at the horizontally opposite ends of said passageway, said oven having vertically extending entrance and exit openings adjacent the ends of the said arcuate side wall and in alignment with said passageway to accommodate the said lamps, a heating chamber in said oven behind said supplementary wall and adjacent the end thereof contiguous to said entrance opening, means to heat air within said chamber, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the end of said passageway adjacent said exit opening and at an acute angle thereto to connect said blower, duct, passageway and chamber in a closed circuit for horizontal flow of heated air through said passage in a direction contra to the movement of the lamps therethrough.

10. The combination with a machine of the class described comprising a turret having at the periphery thereof a series of heads for holding elongated tubular lamps vertically depending therefrom and for advancing them along an arcuate path of movement, of an oven including side walls and a roof and a floor, one of said side walls being arcuate and coextensive with a portion of the said path of movement of the lamps, a supplementary arcuate wall member of sheet metal located within said oven concentric with said arcuate side wall and spaced therefrom to define therebetween a horizontal passageway enclosing said portion of the said path of movement of the lamps, said supplementary wall member extending vertically to the roof and floor of the oven but terminating short of the side walls thereof to leave vertically extending end openings at the horizontally opposite ends of said passageway, said oven having vertically extending entrance and exit openings adjacent the ends of the said arcuate side wall and in alignment with said passageway to accommodate the said lamps, a heating chamber in said oven behind said supplementary wall and adjacent the end thereof contiguous to said entrance opening, means to heat air within said chamber, a blower having its intake side communicating with said heating chamber, and a duct leading from the outlet side of said blower to the end of said passageway adjacent said exit opening and at an acute angle thereto to connect said blower, duct, passageway and chamber in a closed circuit for horizontal flow of heated air through said passage in a direction contra to the movement of the lamps therethrough, means defining a concave pocket at the far end of said duct arranged to sharply divert the flow of air from said duct into said passageway and across the adjacent exit opening at a high speed to form an air curtain across said opening, and deflector members in the end of said passageway adjacent the entrance opening and arranged to deflect the air stream across said entrance opening toward said heating chamber.

References Cited in the file of this patent UNITED STATES PATENTS 884,427 Standish Apr. 14, 1903 99,513 Morrison Apr. 30, 1935 5,7 6 Fulton et al. Nov. 20, 1951

Images