US2119282A - Spray booth - Google Patents

Description

' May 31, 1938. J LUDWIG 2,119,282

SPRAY BOOTH Filed Aug. 24, 1936 INVENTOR.

BY f QJHNE. LUUWIE WQ ATTORNEY.

Patented May 31, 1938 SPRAY BOOTH John E. Ludwig, Detroit, Mich, assignor to De Vilbiss Company, Inc., Toledo, Ohio, a corporation of Ohio Application August 24, 1936, Serial No. 97,533

11 Claims.

My. invention pertains to ventilated spraying booths and more particularly to spraying booths of the type suitable for continuous production spraying.

It is an object of my invention to provide a ventilated spraying booth comprising a forced alrinlet header having air directing means associated therewith for directing a flow of air downwardly at relatively low velocity adjacent the object being sprayed and having high velocity air projecting means for projecting a thin blast or sheet of air downwardly at high velocity between the object and the low velocity air to aid the operator in applying a smooth even coating of paint on the object and to protect him from inhaling the poisonous fumes thereof.

It is a further object of my invention to provide a spraying booth comprising an air ventilating means wherein fresh air'is forced into the 20 spraying booth through an inlet header which comprises low velocityvdirecting outlets on the lower wall at opposite sides of the housing for directing a large volume of air downwardly at low velocity on opposite sides of the object being 25 sprayed, also narrow air projecting nozzles for projecting thin sheets of air downwardly at high velocity adjacent the opposite sides of the object between the object and the low velocity air,v and additional air projecting means for projecting a 3 sheet of air at high velocity across the ceiling between the downwardly projected air streams. The purpose of this sheet of air at high velocity crossing the ceiling is not only to aid in carrying ofi fumes, but it is also useful in preventing the curtains of high velocity air from creating a vacuum adjacent the object being sprayed which would then otherwise tend to cause said high velocity air streams to hug tightly to the object being sprayed. This laterally projected air subsequent to its travel across the ceiling moves downwardly comparatively slowly between the downwardly projected high velocity air streams permitting them to maintain a substantially direct path from inlet tooutlet.

It is also an object of my invention to provide a ventilated spraying booth comprising a floor having spaced exhaust apertures therein, an exh'aust fan for drawing air rapidly from the booth through the exhaust'apertures, an air intake fan having air directing means for directing a volume of fresh air downwardly on opposite sides of the object to be sprayed, and air projecting nozzles for directing thin sheets of air downwardly at high velocity adjacent the opposite sides of the object between the object and the large volume of downwardly directed air whereby the ventilating air is aided by gravity in carrying the obnoxious spray vapors awayfrom the operator.

The invention, however, both as to it's organization and its method of operation together with additional objects and advantages thereof will best be understood from the following descript-ion of a specific embodiment, when read in conjunction with the accompanying drawing, in which:

Fig. 1 is a side elevational view of my ventilated paint spraying booth partially sectioned and .broken away to clearly show the internal construction thereof and the circulation of air provided therein;

Fig. 2 is an enlarged sectional view thereof showing the arrangement of the ,inlet header with the high velocity air projecting nozzles and the low velocity air directing grills; and

Fig. 3 is an elevational view of a low velocity air admitting grill provided in one side of the ventilating header.

Referring more particularly to Figs. 1 and 2 of the drawing, my ventilated spray booth comprises a housing enclosed by side walls I and 3 and a roof 5 through which the objects to be sprayed are continuously passed. The spray housing is provided with a floor I spaced above the floor 9 of the factory and provided with apertured exhaust grills H and I3 which are spaced from the side walls i and 3 of the housing. The exhaust grills H and I3 are extended horizontally along the floor I of the housing, and may comprise any suitable open-work grating or the like. The objects to be sprayed are transported through the spray boothover the floor "I and between the exhaust grills II and I3 in any convenientmanner as on an endless conveyor for example.

For supplying ventilating air to the spray booth, I provide a motorized exhaust fan l5 therein for drawing air through an air intake conduit H which extends upwardly and passes through the roof ill of the factory, where fresh air is drawn in through an elbow-2|.

For properly distributing the ventilating air in the spray booth to carry the poisonous fumes away from the workman and to aid him in properly distributing the sprayed material to provide a smooth coat upon the object, the lower end of the intake air conduit i1 is provided with a transversely disposed header 23 of flat shallow construction which is transversely disposed in the spraying booth over the objects to be sprayed.

sprayed. The panel 29 extends the length of the header between the end walls thereof and is provided with marginal flanges 3| and 33 at its left and right hand edges respectively which are turned upwardly in a substantially vertical position. Parallel to and spaced from the upturned flange 33 at the right hand edge of the panel 29, I provide a vertical partition 35 which rises from the lower wall of the intake header.

The uppermost edge of the partition 35 is provided with a vane 39 which is turned horizontally toward the center of the header and is suitablyspaced from the upper wall 31 of the header to deflect the air and to define an air inlet conducting passage of suitable size for receiving the air which passes downwardly through the grill 21 of the header with relatively "low velocity. The vertical panel-flange 33 likewise carries at its upper edge vane portion 4| turned toward the center of the header and which, with the vane 39, defines a passage for deflecting and receiving the proper volume of air which passes downwardly through the duct defined between the flange 33 and the partition 35 into the spray booth. The vertical walls 33 and 35 thus define a nozzle for projecting a flat blast or sheet of air downwardly with high velocity adjacent the side of the object being sprayed and between it and the larger volume of low velocity air which is directed downwardly from the grill 21.

For directing a sheet of high velocity air under and adjacent to the concave face of the closed panel 29, I provide a vertically disposed partition wall which extends across the header in spaced relation from the left hand panel-flange 3| and which, along its lower edge, is provided with a horizontally disposed flange 45 which projects underand spaced from the closed panel 29. The air deflecting flange 45 is provided along its edge with an upturned vane portion 41 which is spaced substantially parallel with the under surface of the panel 29 whereby a thin jet or sheet of air is projected at high velocity along the under side of the panel 29 toward the jet of air which is projected downwardly from the right hand side of the panel 29. The vertical partitions 3| and 43 are preferably provided at their upper edges with deflecting vanes 44- and 46 respectively turned toward the center of the header.

For projecting a high velocity sheet of air downwardly adjacent the left hand side of the object being sprayed, I provide a vertical partltion 49 which passes through the header in par allel spaced relation from the partition 43 and defines a high velocity projecting duct therebetween. This high velocity nozzle projects a sheet of air downwardly between the object being sprayed and the larger volume of low velocity air passing downwardly from the grill 25 at the left hand side of the panel 29. The upper edge of the partition 49 is provided with a horizontally disposed flange 5| which projects 4 toward the middle of the header and is spaced. from theupper wall 31 of the header for defining an air conducting passage suitable for passing a proper volume of air from the conduit through the low velocity grill 25. The low velocity air inlet grills 25 and 21 respectively may be of any suitable open-work but I preferably providea grill comprisinga plurality of metallic bars 53 securedtogether in parallel relation by transversely disposed rods 55, as shown in Fig. 3. For providing eflicient illumination, a circular aperture 58 is provided in the center of the grill for mounting the reflector and defusing globe of a suitable illuminating unit which, as will be readily understood, may be of suitable streamlined conformation to avoid setting up eddies in the air stream.

F or efliciently exhausting the air from the spray booth and to aid the air projecting nozzles and grills in providing a smooth uniform circulation of the air therein, I provide an exhaust fan 51 which is connected through a conduit 59 which connects into the air space defined under the floor 1. At the left hand side of the exhaust grill II, a partition 61 is preferably inserted for restricting the exhaust passage defined thereunder.

In operation, the objects to be sprayed are moved through the spray booth in any suitable manner as upon a continuous conveyor (not shown), and as the attendant standing at one side of the spray booth sprays the object, the

high velocity sheets of air 1| and 13 respectively projected downwardly on opposite sides of the object tend to protect him effectively from inhaling the poisonous vapors.

If the paint spray is discharged strongly against the object being coated there is considerable rebound of spray fumes which occasionally penetrate the high velocity streams. The addition of low velocity air between the object and high velocity streams impedes the rebound and thereby assists the high velocity streams in preventing the fumes from reaching the operator.

Also the larger steams 15 and 11 of low velocity air projected downwardly from the grills 25 and 21 insure the sprayer a fresh supply of air at all times, and the circulation of the air above andaround the object at all times aids in properly applying a smooth coat of the sprayed material upon the object.

The jet of high velocity air coming through the passage between the vertical partitions 3| and 43, and which starts out in the direction of the arrows under the panel 29 becomes substantially two low velocity streams of air passing downwardly on each side of the article being sprayed, due to the eddies or suction effect set up between high velocity streams 1| and 13.

The turns and narrow sections of the passage for the air passing between vane 41 and panel 29 prevent the resulting air jet from having as much bulk or as high velocity as the vertical sheets of air 1| and 13. It therefore is lacking in carrying power and is influenced by the downward pull of the suction set up by the high velocity sheets 1| and 13. A portion of the jet near sheet 1| will be attracted by it and travel with it to the exhaust opening while a major part of the jet will continue forwardly until it is turned downwardly by sheet 13. The general downward movement of the air jet is caused by the pull of the air sheets 1| and 13 and has therefore less velocity than have these sheets.

The above advantages are also augmented by gravity when the air inlets are above the outlets. In applicant's construction more effective protection is provided for the attendant whereby he can closely and clearly see his work.

Although I have shown and described a specific embodiment of my invention, I am aware that many modifications are possible, my invention therefore is not to be restricted except insofar as it is limited by the prior art and the scope air inlet header associated therewith, low velocity directing means connected with said header for directing a large volume of air to flow in a path adjacent the object being sprayed, and an air projecting nozzle for projecting a sheet of air at high velocity between said large volume of moving air and the object being sprayed.

2. A ventilated spray booth having air supply means for supplying fresh air to said booth, an air inlet header connected therewith, an open grill in the lower wall of said header for directing a large volume of air to fiow in a path adjacent the object being sprayed, and an elongated air projecting nozzle opening from the lower face of said header for projecting a thin sheet of air to flow downwardly at high velocity between said large volume of downwardly flowing air and the object being sprayed.

3. A ventilated spray booth having air supply means for supplying fresh air to said booth, an air inlet header connected therewith, spaced air projecting nozzles for sheets of air at high velocity on opposite sides of objects to be sprayed and means for supplying lower velocity air between said sheets of air at high velocity.

4. A ventilated spray booth having an air inlet conduit for supplying fresh air to said booth, an air intake fan for forcing the air downwardly through said conduit, an air inlet header connected therewith, low velocity air directing means in the lower face of said header at opposite sides thereof comprising an open grill work for directing large volumes of air downwardly on opposite sides of the object being sprayed, elongated slots in the lower face of said header at the adjacent edges of said spaced grills for directing thin sheets of air downwardly at high velocity adjacent the inside each stream of slow moving air.

5. A ventilated spray booth having a housing enclosed by side walls and a roof for defining the space through which objects are transported to be sprayed, a floor in said housing, spaced exhaust apertures in said fioor, for drawing air from said booth at opposite sides of the sprayed object, an exhaust fan connected for drawing air therefrom, an air supply conduit for supplying fresh air in said housing, an intake fan associated therewith for forcing air downwardly through said conduit, an air inlet header connected therewith, low velocity air directing means for directing streams of air downwardly adjacent opposite sides of the sprayed object, and high velocity air projecting means associated with said header for projecting thin sheets of air downwardly at high velocity on both sides of the sprayed object between the object and the slowly moving streams of air.

6. A ventilated spray booth having a housing for enclosing a space through which objects may be passed for spraying comprising side walls and a roof, a floor in said housing, spaced exhaust apertures in said floor, an exhaust fan for drawing air rapidly from said housing through said exhaust apertures, an air inlet conduit for supplying fresh air to said housing, an air intake fan for forcing air downwardly through said conduit, an air inlet header connected therewith,

high velocity air projecting means associated therewith for projecting thin sheets of air downwardly at high velocity in spaced relation toward the spaced exhaust apertures in said floor, and low velocity air directing outlets in said header for directing large volumes of air downwardly outside of said high velocity sheets of air.

7. An air inlet header for ventilating a paint spraying booth comprising an elongated casing of flattened conformation adapted to be connected with an air inlet conduit, a solid ceiling panel extending across the middle of the lower wall of said casing, air outlets of substantially broad area on opposite sides of said panel, and elongated slots extending along the opposite edges of said panel adjacent said outlets for projecting thin sheets of air therefrom.

8. An air inlet header for ventilating a paint spraying booth comprising an elongated casing of flattened conformation adapted to be connected with an air inlet conduit, a solid ceiling panel extending across the middle of the lower wall of said casing, air outlets of substantially broad area in the lower face of said header on opposite sides of said panel, elongated slots along the opposite edges of said panel adjacent said outlets for projecting thin sheets of air therefrom at high velocities, spacedpartition walls projecting into said header from the opposite edges of said slot for defining an air projecting nozzle and passage connecting from the interior of said header.

9. An air inlet header for ventilating a paint spraying booth comprising an elongated casing of flattened conformation adapted to be connected with an air inlet conduit, a solid ceiling panel extending across the middle of the lower wall of said casing, air outlets of substantially broadarea in the lower wall of said header on opposite sides of said panel, elongated slots along the opposite edges of said panel adjacent said outlets for projecting thin sheets of air therefrom, spaced partition walls projecting into said header from the opposite edge of said slot for defining an air projecting nozzle and passage connecting from the interior of said header, a ceiling panel ventilating slot extending adjacent one edge of said panel, and an air projecting -vane connected from the lower edge of said slot spaced from and substantially parallel to the lower face of said panel for-directing a thin sheet of air thereacross.

10. An air inlet header for ventilating a paint spraying booth comprising a flat casing having air outlets of broad area spaced in the lower wall on opposite sides of the header, a solid panel disposed in the lower face of said casing between said outlets, said panel comprising a concave lower face, an air projecting nozzle for projecting a thin stream of air at high velocity across the lower face of said panel, spaced air projecting nozzles of elongated conformation disposed on opposite sides of said panel for projecting thin sheets of air downwardly at high velocity therefrom, and partition walls projecting inwardly into said header from the opposite sides of said slots for defining air ducts or nozzles leading thereto and for providing sufficient back pressure to project the high velocity blasts of air while directing a suitable volume of air to supply the large low velocity openings.

11. A ventilated spray booth having air supply means for supplying fresh air to said booth, an air inlet header associated therewith, a discharge nozzle for projecting a sheet of air at high velocity to one side of the object being sprayed and discharge means for projecting air at low velocity on both sides of the sheet'of high velocity air.

JOHN E. LUDWIG.

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