US2434911A - Heating and spraying device - Google Patents

Description

Jan; 27, 1948.

l. P. DENYSSEN HEATING AND SPRAYING DEVICE Filed Dec. 26, 1944 v n 2 Sheets-Sheet 1 N mm m mw .M mm & mw hm m mm aw me mw m m ww an M a H W Nu w Q N M N. H \\.%N N \m H E V w aw 5 MM MN &\ M I 9% NM/ NM; w w W l$\\ 5w w Sv mm A TTO IVE) Jan. 27, 1948. N N 2,434,911

HEATING AND SPRAYING DEVICE Filed Dec. 26, 1944 2 Sheets-Sheet 2 I N V EN TOR. /V.4/V//0f I? DEN YS'Sl-W BY P ATTO NE) Patented Jan. 27, 1948 HEATING AND SPRAYING DEVICE Ivanhoe P. Denyssen, Lansdowne, Pa., assignor to Federal Telephone and Radio Corporation, New York, N. Y., a corporation of Delaware Application December 26, 1944, Serial No. 569,736

2 Claims. (01. 219-39) The present invention relates to improvements in heating and spraying devices and has for its object to provide a portable, compact spraying device or spray gun assembly of a self-contained and trigger control type, particularly adapted for the melting and spraying of metal alloys and the like. -The device is especially useful for metal alloy spraying of the plate electrode coatings of dry rectifier plates such as selenium rectifiers, wherein a low melting point metal alloy is sprayed upon the selenium surface.

The improved spray gun device is designed with a view to incorporating features thereof in a compact and improved balanced relation, whereby in its use as a portable hand tool, in consequence of the improved distribution of the weight with relation to the supporting grip or handle, it will materially facilitate the spraying operation with a minimum of fatigue to the operator. It further includes a favorable thumb action, trigger or valve control, conducive to accuracy in the control of the spraying operation without impairing the firm support and guidance of the device in its use as a hand tool.

A further object of the invention is to provide a self-contained spraying device providing for an air intake longitudinally through the handle portion thereof, whereby the latter is cooled and wherein the air then is passed through a heating coil in its passage to the spray nozzle, and wherein electrical resistance heating elements are positioned to be effective for heating both a metal container or crucible and the air within the heating coil to obtain an improved degree of efficiency. It further includes an advantageous provision for the passage of the heated air closely about the nozzle portion for contributing heat thereto by conduction so as to maintain an efficient operating temperature during the spraying action. It is further arrranged for simultaneous operation of the metal and air control valves in normal operation, adjustment of their feed ratios and further for a convenient independent opening of the air valve for initial heating of the nozzle when desired to insure fluidity of the metal in its passages.

A further object of the invention is to so incorporate or organize the features thereof in an improved balanced arrangement for use as a portable tool, wherein the handle and body assembly is so constituted as to obtain an advantageous distribution of the weight, contributing to its facility of use while leaving one hand free. To this end it is designed to be close coupled with a generally cylindrical body structure including within its vertical plane the major portion of the valve structure and having an angularly disposed supporting handle providing an inner hand support closely adjacent to the body. This is combined with a valve trigger control wherein the operating trigger is positioned above the handle for operation by the thumb of the operator with the pressure applied toward the supporting fulcrum point and to the side opposite that of the greater weight. There is thus obtained a minimum of disturbance to the steadiness of support or balance in the operation of the valve.

The described and other features and advantages of the present improvements will be more fully understood by reference to the accompanying drawings wherein like reference characters are applied to the corresponding parts in the several views, in which drawings:

Fig. 1 is a central, vertical sectional view of the heating and spraying device embodying the features of the invention;

Fig. 2 is a top plan view thereof;

Fig. 3 is a view thereof in side elevation taken from the left of Fig, 1, and

Fig, 4 is a circuit diagram, illustrating the use of two thermostats for controlling the heating of the sprayer.

In the preferred embodiment of the invention as illustrated, the improved structure includes a generally cylindrical arrangement of a container or crucible for the heating of the material to be sprayed, which is surrounded by multiple electric resistance heaters and likewise by a heating coil forming a part of the passage for the air or gas supplied under pressure to a nozzle portion for the atomizing of the melted metal in the customary manner. In accordance with the invention this air heating coil is disposed between the cylindrically formed electric resistance heaters, whereby the latter function to heat both the metal bath and the atomizer air supply for added efiiciency and related heating action.

In the construction as shown, I indicates a cylindrically formed receptacle or crucible for the metal supply which, as indicated, may be open at its upper end and has its bottom wall 2 formed with a cylindrical downward extension or bearing portion 3 which is internally threaded at 4 for the reception and support of the threaded nozzle 5 having a cylindrical body portion with a longitudinal bore 6 therethrough with the lower end portion of its wall inclined or of conical formation terminating in a conical valve seat 1 and central discharge opening or port 8. The upper end of the nozzle member 5 is formed with openings 9 in its side wall positioned immediately within the metal receptacle and has threaded to its upper end a bearing or bushing I providing a slidable support for the metal control rod, or needle type valve l I having a tapered or conical lower end l2 cooperating with the valve seat I. The enlargement of the bore 6 relative to the diameter of the rod H provides a cylindrical passage through which the melted material or fluid alloy descends by gravity for atomizing under the influence of a heated air supply or jet passed through a nozzle opening encircling the discharge end of the nozzle member I.

The supply of air or inert gas under pressure from a, suitable supply source (not shown) is through an air conduit l3 positioned within a handle or grip l4 secured to a housing member composed of an upper valve housing and support l5, a lower support l5 and connecting cylindrical casing H. The conduit [3 communicates through a valve passage l8 formed in the member [5 with a vertical passage I!) connected to the upper end of the air heating coil 20 communioating at its lower end through vertical and horizontal passages 2| and 22 with an annular chamber 23 formed in the extension portion 3 and connected by a multiplicity of vertical passages 24 with the discharge chamber 25 of an outer nozzle or mouth member 26 having a discharge opening 21 encircling the lower end of the discharge port 8.

The air in its passage from the intake conduit l3 to the discharging port 21 passes through the heating coil which, as shown, is positioned concentrically with and surrounding the crucible I. For the purpose of simultaneously heating the air and the material or metal within the crucible, electric resistance heating elements are employed which are so incorporated as to simultaneously heat both the air and the metal alloy with an improved degree of efiiciency and with a uniform ratio of heat conduction. The arrangement provided therefor consists of the concentrically disposed cylindrical heating elements 28 and 29 supported between the housing members I5 and IS with the innermost heatin element immediately surrounding the crucible l and with the air heating coil 20 positioned between the heating elements as shown. These resistance heating elements in accordance with known practice are composed of an outer metal casing enclosing coils of resistance Wire 30 packed within insulating material (not shown for the sake of clarity) of high heat conductivity such as mica. The electrical connections to the heating element are desirably passed through a longitudinal bore 3i in the handle l4, and included in the heater circuit is a thermostat circuit control unit 32 suitably housed in member it to be responsive to the heating influence or conduction from the metal bath and heated air supply as will be readily understood.

The improved spraying device in accordance with the present improvements provides under normal operation for the simultaneous valve control of both the metal and air supplies, with further inclusion of provision for relative adjustment of the valves for obtaining the desired feed ratios. In the arrangement as disclosed, the valve housing support l5 provides an upper bearing bracket 33 for the metal valve or control rod ll providing, by means of a bushing 34, the bearing for the rod and also for a compression spring 35 hearing at its lower end upon a sleeve or collar .36 secured on the rod and thereby operating normally to depress the valve rod H for closing of the metal feed discharge port 8. Threaded upon the upper end of the valve rod II is an adjustable thumb-nut 31 and lock-nut 38, the former providing a bearing for a valve lift lever for manual control of the valve rod.

The valve control lever arrangement includes a main control lever 39 having a split and attached to the pin 40 rotatably supported within the valve housing extension 4|. A lever finger extension 42 is fixed to the pin 40 and engages the underside of the thumb-nut 38. A thumb lever extension or trigger 43 integral with control lever 39 overlies the handle I4. A lever 44 integral and opposite to extension 42 has coacting engagement with a bell lever 45 fulcrumed at 46 for the simultaneous control of an air valve. The air valve is composed of a valve plunger or rod 41 operating within the air passage la in cooperation with a valve seat bushing member 48 fitted within the inner end of the passage and providing communicaiton with air passage ill. The air valve rod 41 is slidably mounted in the sleeve 49 secured in and closing the outer end of the air passage I8, and providing a shoulder bearing compression coil spring 50 engaging a valve flange 5| to be operable normally to close the latter. The outer end of the valve rod 41 has threaded thereon the adjustable thumb-nut 52 and lock-nut 53, the former being engaged on its inner surface by an arm of the bell lever 45. In consequence of this valve construction depression of the trigger extension 43 toward the handle M will efiect simultaneously a lifting of the metal control valve rod H and by motion transmitted through the levers 44 and 45 will lift or open the air valve 47 and in consequence open the air supply. The relative adjustments as effected by the thumb- nuts 31 and 53, as will be readily understood, permits of accurately regulating the valve openings to establish the desired operating ratio in the feed of the metal and air. The valve arrangement as associated with the operation of the air valve will also permit, if desired, of independently opening of the air valve by means of the thumb-nut 52 while the metal control valve remains closed, which may be desirable under certain conditions for initially heating the nozzle 5 preliminary to the spraying action.

The improved spray gun of the construction as shown is particularly adapted and of design and arrangement to facilitate its employment as a portable tool for the spraying of coatings of metal or other material upon horizontally supported surfaces. The improved arrangement of the electrical resistance heating elements in close heat conducting relation to both the crucible for the heating of the metal and to the air heating coil provides for greater heating efiiciency together with an established or uniform heating relation for conduction to both mediums which incident to the thermostatic control of the heating elements contributes to the uniformity of heat regulation throughout the spraying operation. The method employed for admitting the air through the grip portion provides for desirable cooling oi the handle and the conduction of the air from the heating coil through a multiplicity of vertical passages surrounding the nozzle of the member maintains the heating of the latter during the spraying operation and in addition permits preheating of this nozzle member as described. The arrangement of the valve mechanism wherein the major portion of the. structure isebove and within the cylindrical plane of the body portion, together with the concentric arrangement of the heating elements provides a desirable concentration and centralizing of the weight permitting of a close coupled attachment of the supporting handle in angular relation as indicated. The under portion of the handle is further formed with a curved fillet or fulcrum supporting portion 54 adapted for support at the base of the forefinger of the operator in a manner contributing to steady support and reduction of fatigue in the manipulation of the tool. Th later coupled with the provision of the trigger control overlying the upper end of the handle for thumb action permits of manipulation With a minimum disturbance to the operators grip and to the balancing of the device in that the pressure is applied at the opposite side of the point of support from that of the greater weight and with the pressure in the direction of the handle. As an advantageous structural feature the air conduit or tube I3 is threaded at its opposite ends for securing engagement of the housing I 5 and to function as a support handle and securing means for the handle; a securing nut 55 being received on its outer threaded end for clamping of the handle or grip in position. At 56 is shown a threaded plug for the closing of the outer end of the passage 22 and at 51 there is shown a spaced insulating supporting plate for the inner portion of the handle member.

In Fig. 4 there is diagrammatically shown a desirable modification on the heating coil circuit arrangement wherein separate thermostat control switches are associated in series With each of the outer and inner resistance heatin elements 28 and 29. These thermostat control switches are indicated at 58 and 59 respectively. In this arrangement, wherein the inner and outer heating coils are independently and thermostatically controlled, the outer heating control thermostat is desirably set to open the circuit at a relatively higher temperature than that of the inner coil immediately surrounding the metal bath. The advantage of this arrangement is that upon opening of the inner heating element circuit in response to increase of metal bath temperature the outer heating element will still maintain a closed circuit for continued heating of the air supplied to insure of proper heating during the period of cooling down of the metal, which is slow or has a time lag incident to the residual heat thereof and through which slowing down period the air might become so cold as to impair the operation by cooling of the nozzle.

While there is illustrated a preferred embodiment and one modification of the features of the invention, it will be understood that varied modifications may be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1, A portable heating and spraying device comprising a support provided with a hand grip, a crucible for the material to be melted and sprayed, spaced electrical resistance heating elements positioned to surround the crucible, a nozzle member having a discharge opening and passage communicating with the crucible, said crucible being formed with a lower nozzle bearing extension to which the nozzle is threaded and formed to provide a chamber and passages surrounding the nozzle, a conduit for a pressure and gaseous medium including a heating coil surrounding the crucible and interposed between the resistance heating elements, said conduit communicating with the chamber and passages of the crucible bearing extension, an outer nozzle member secured to the bearing extension to provide a continuation of the air passage surrounding the nozzle and provided with a discharge port encircling the nozzle discharge opening, valve means operative to control the flow of material and gaseous medium to the nozzle, said supporting grip being formed to provide an intake to the gaseous medium conduit, and operating connections for the Valve means having a trigger lever associated with the grip and adapted simultaneously to open the valve means, said operating connections having means for adjusting the degree of the valve opening and being adapted to permit independently opening of the gaseous medium valve.

2. A portable heating and spraying device comprising a support provided with a hand grip, a crucible for the material to be melted and sprayed, spaced electrical resistance heating elements positioned to surround the crucible, a nozzle member having a discharge opening and passage communicating with the crucible, said crucible being formed with a lower nozzle bearing extension to which the nozzle is threaded and formed to provide a chamber and passages surrounding the nozzle, a conduit for a pressure and gaseous medium including a heating coil surrounding the crucible and interposed between the resistance heating elements, said conduit communicating with the chamber and passages of the crucible bearing extension, an outer nozzle member secured to the bearing extension to provide a continuation of the air passage surrounding the nozzle and provided with a discharge port encircling the nozzle discharge opening; normally closing spring pressed valve means operative to control the flow of material and gaseous medium to the nozzle, said supporting grip being formed to provide an intake to the gaseou medium conduit, and operating connections for the valve means having 'a trigger operating lever associated with the grip and adapted simultaneously to open the valve means, said operating connections having separate means for adjusting the degree of the respective openings and adapted to permit independently opening of the gaseous medium valve.

IVANI-IOE P. DENYSSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,200,766 Searles Oct. 10, 1916 1,792,551 Rice et al Feb. 17, 1931 2,082,061 Jenkins June 1, 1937 2,107,686 Bramsen et al. Dec. 14, 1937 2,291,423 Tiscornia July 28, 1942

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