US2120583A - Air heater - Google Patents

Description

P. J. TIMBERLAKE June 14, 1938.

AIR HEATER 2 Sheets-Sheet 1 Filed Oct. 16. 1936 Fkul L]. Timberlake June 14, 1938. P. J. TIMBERLAKE AIR HEATER Filed Oct. 16,-1956 2 Sheets-Sheet 2 Raul filler-1m 1 a Patented June 14, 1938 UNITED. STATES PATENT OFFICE 6 Claims.

The present invention relates to improvements in portable air heater construction and has particular-referenceto air heaters especially adapted for use in connection with the service of automobiles and the like. While concerned broadly with apparatus for heating and discharging a stream of airunder pressure; the design of the present invention as herein illustrated is particularly suitable for the uses advocated in United States .Patent No. 1,997,039 of the air heater disclosed therein.

Briefly my improved heater construction comprises a portable framework within which is supported a removable carrier supporting one or -more resistance heat elements. At one end of the framework, structure is provided for connecting the interior of the heater with a source of air under'pressure while at the opposite end a nozzle distributes the heated air as it leaves the chamber surrounding the carrier-for the resistance element. One aspect of the invention consists of'the novel arrangement of the parts going into the construction of the-framework of my heater. which expedites assembly and reducescost of production. Another is present in the novel construction of the removable carrier supporting the resistance heating. element which-gives efflcientand rapid heating of the air and prolongs the life of the heating element. Other features .of the invention include the air coupling and air adiustment structures.

In ;the drawings:

Fig.4 is a side elevational view partly shown in broken cross-section 'of one form of air heater embodying the present invention,

Fig..2 is a cross-sectional view through the barrel ofthe air heater taken on the line IIII ofwFig; 1,

Fig.3 is a fragmentary side elevational .view of the clamping yoke showing its adjustability for various sizes of air chucks,

Figs. 4 and 5 are side elevational views of modified types of attachment tips,

Fig. 6 is a cross-sectional view of a stepped conical shaped collar for use in connection with the attachment tip,

Fig. '7 is a cross-sectional view of another form of tip to be used with the air heater,

Fig. 8 is an end view of the carrier with an insulated spacing ring connectedthereto,

Fig.- 9 is a vertical cross-sectional view taken on :the center line of Fig. 8,

Fig. .10 is a fragmentary cross-sectional view similar to Fig. .1 of another form of barrel and assembly construction with the carrier construction shown in Figs. 8 and 9 shown in assembled position,

Fig. 11 is an end view partly shown in crosssection of the barrel construction showing mechanism for controlling the heat and air supply to the heater, and

Fig. 12 is a broken perspective view showing a suitable arrangement for controlling the heating capacity.

In the form of the invention illustrated in Fig. 10 1 the heater l0 comprises a cylindrical barrel generally designated l2, headers I4 and iii, a handle l8 and a nozzle 20. The barrel i2 is preferably fabricated from a tube 22 of expanded metal concentrically disposed in spaced relation 15 from a sheet metal tube 24. Likewise concentrically arranged within and spaced from the tube 24 is a tube 26, the space between the tubes 24 and 26' is shown as filled with a suitable insulating material such as loose asbestos. Support 20 is given the spaced tubes 22, 24 and 26 through cylindrical shoulder portions upon the headers l4 and I6 which are preferably of cast metal. Opposed conical recesses 28 and 30 are provided in the headers i4 and Hi to support opposite ends 25 of the carrier 32 upon which is wound the electrical resistance heating element 34. The tubes 22, 24 and 26 and the carrier 32 are maintained in their assembled relation by screws 36 or other suitable fastening instrumentalities securing the 30 ends of thetube 22- to the headers l4 and 16. By removing the screws 36 all the parts supported between the headers I4 and I6 may be removed. This arrangement enables the parts to be readily replaced and greatly simplifies the assembly and 35 reduces the cost thereof. The specific construction of the carrier 32 and the manner in which the heating element is wound thereon is an important feature of the invention. As shown in Figs. 1 and 2 the carrier 32 has a fluted outer 40 surface upon which the heating element 34 is spirally wound. Preferably the ridges 38 between adjacent flutes are notched along an interrupted spiral path to receive the element 34 thus preventing the same from shifting axially 45 of the carrier 32 during use. With such a construction as will be clearly understood from Fig.

2, the major portion of the heating elements 34' will be spaced from the surface of the carrier 32 affording access of the air to be heated to all 5 sides of the heating element 34 spaced between the ridges 38. The terminals for the heating elements 38 are shown at 4|] and 42. To expedite the. winding of the carrier 32 and to avoid imbedding any portions of the same, an axially 55 extending groove 44 is provided along which the heating element extends from the terminal 40 to the left end of the carrier 32 as viewed in Fig. 1 to the starting point of the spiral Winding extending back to the terminal 42. The carrier 32 may be of any suitable insulating material and is preferably molded as an integral section. A suitable electrical connector 43 extends through a seal (not shown) in the header I6 and is connected to the terminals 49 and 42. The connector 43 in most cases will be provided with a suitable plug for connection to the electrical outlet. As the recesses 28 and 30 in which the carrier 32 is supported merge with the air outlet :35 and air inlet 48, respectively, it is desirable to bevel the ends of the carrier 32 as at to provide adequate opening for the passage of air. In production the carrier 32 is loosely supported in the recesses 2d and 36 so as to provide for any expansion. that may take place upon heating and thus avoiding any warping of the carrier 32 or distortion or loosening of the barrel I2.

The outlet 36 is threaded to receive various nozzles and conduit structure. As illustrated in Fig. 1 a nozzle 2?: is provided which is particularly adapted for use in connection with the warming of grease to be removed from a differential housing of an automobile. A tip 52 is threaded into the end of the nozzle 25 for insertion into the usual opening in the differential housing. The conical shaped plug 54 functions to seal such opening under the stress of the spring 58 so as to assist in developing a pressure within the housing for forcing the Warm grease from the differential through the drain opening. The tip 52 is preferably deflected at right angles to the axis of the connector plug 54 to enable the tip to be hooked behind the adjacent wall structure defining the opening in the differential housing.

As the heater shown in Fig. 1 is particularly designed to be used in garages and service stations for automobiles equipped with air pressure, the heater I6 has an integral projection 53 upon which there is provided a seat 60 for an air chuck t2 of well known construction imposed in the air line 66. For clamping the chuck E2 to the seat a yoke 6t is provided in which a thumb screw 68 is carried for engaging with the chuck To accommodate the various size air chucks that are found in use on the market the yoke as shown in Fig. 3, has a plurality of vertically aligned openings iii in which the attachmerit screws l2 may be selectively inserted to fasten the yoke 68 to the projection 58 in varied adjustment with respect to the position of the screw 68 with reference to the seat 69. The seat 66 embraces an opening M which communicates with the chamber l6 opening into the recess 48. Admission of air and regulation of the quantity of air to the heating chamber is controlled by an. adjustment screw I8 threaded in the projection 58 at 8B. The end of the screw I8 is shown reduced at 82 to engage and lift the poppet valve 84 from its seat to permit fiow of air through the air line 64 into the interior of the heater. By regulating the screw 18 the amount of air admitted past the valve 85 may be controlled. The path of the air through the heater and nozzle 20 is indicated by the arrows.

In Fig. 4 a modified form of tip 86 is shown which is threaded into the nozzle 20 in a manner similar to that shown in Fig. 1 but in lieu of being angularly disposed to the axis of the conical plug 5t it is provided with an integral projection 88 which engages back of the wall 98 adjacent the wall structure defining the opening 82 which may be that found in the differential of an automobile. The tip arrangement 94 shown in Fig. 5, in lieu of the integral projection 88, a rivet 9% has been passed through the end of the tip 94 to provide a suitable hooking construction for engagement with the wall structure adjacent the opening through which the tip may be inserted. A modified construction B8 is shown in Fig. 6 which in lieu of having a smooth conical surface as the plug 54 a series of stepped circular shoulders I96, I02 and I M are provided equipped with gaskets Hi8 to enable the plug to be used with various size openings and give a more effective air seal than may be found pos-- sible with the conical plug 54. In Fig. '7 a tip construction I08 is shown which may be threaded into the nozzle 29 in the manner of the tip 52 where it is desirable to spray the heated air against an object to be warmed up or thawed out. To get a good distribution of the air the tip I08 may have slots H0 and H2 at right angles to fan out the air as it passes through the nozzle.

In Figs. 8 and 9 an insulating ring II9 of nonabsorbing material such as mica, porcelain and the like is shown fitted over an end of the carrier 32 for the purpose of further insulating the electrical heating element from the cast headers I4. This precaution may be advisable in cases where the carrier 32 is made up from a molded insulating material containing asbestos or similar material which may absorb sufiicient moisture to become a conductor. As will be understood a ring II9 will be used at opposite ends of the carrier 32. In Fig. 10 the modified carrier construction in Figs. 8 and 9 is shown supported in position upon one of opposing headers I23 provided with circular slots I28 and internally threaded circular slots I30. In assembling the parts defining the barrel construction the expanded metal tube I32 is merely inserted in the slot I28 and with the insulating rings H9 at opposite ends of the carrier 32 loosely received in the opposed recesses I 34 the tube I36 is threaded into the headers I26 which will tie the headers and barrel defining parts together in assembled relation. In lieu of having two sheet metal tubes for defining the space in which the insulating material is housed as shown in the construction of Fig. l a molded tube I33 of suitable insulating material is shown externally supported within the tube I 36 but without any internal support other than its own bond. I have also found it practical to use the insulating tube I38 without the supporting and shielding tube I 36 :and holding the parts in assembled relation in the manner shown in Fig. 1. Such a construction may be very cheaply manufactured as the heater would consist primarily of an insulated carrier for the heating element and a tube of insulated material defining a chamber within which the carrier is supported by the perforated metal outer shield and spaced headers.

As it is desirable that air be circulated to the heating chamber at all times while the heating element is in a closed electrical circuit to avoid overheating, one suitable arrangement is shown in Fig. 11 for accomplishing this result and making it impossible for the operator to close the electrical circuit in which the heating element is located without first having air under pressure flowing through the heating chamber. As illustrated H8 and I20 correspond to the projection B and the header I 6 of the construction shown in Fig. 1. The heater construction is shown adapted to-a different forrnof air chuck from --that shown'in'Fig. 1 in which the connection is off and adjustment needle valve I24.

"made a bayonet lock. As shown the male member I-I4 carrying a coupling pin is threaded at 'I I6 into the projection I'I8. 'With this type of air chuck at the time the air line is coupled to the-pressure in the conduit I I9 is a piston having a conical head I70 and a body portion I'I4 supported for movement in a bore I13. The piston is loosely supported-in the bore I13 and is lightly held in a raised position by a spring I12. When air under pressure is passing through the cham ber I IS the piston will be lowered until the conical head I10 engages with a complementary seat I'I5 to seal the bore I13. This movement will position a reduced portion I'I'I of the piston in alignment with the pin I66 connected to a slide I19 reciprocated by movement of the button I68 of the toggle switch I64 of well known construction. With this construction it will become apparent that the button I68 can only be rocked to the on position when the air pressure is on and the restricted portion I'I'I is in alignment with the pin I66. It will be understood that the switch I64 is located in the electrical circuit in which the heating element is contained.

In Fig. 12 is shown an arrangement which may be used in connection with my improved heater if it is desired to have a regulation in heating capacity. This may be accomplished by winding the carrier I39 with two separate resistant heating coils I40 and I42 longitudinally spaced along the carrier I39 and terminating in spring terminals I44 and I46, respectively, these terminals being supported on the surface of the carrier I39. As in the case of the carrier 32, the carrier I39 is shown fluted and provided with longitudinally extending grooves I43 through which the electri cal resistance elements are passed for insulating the terminal ends of the heating coils and for spacing the separate heating elements from each other. Suitable spring terminals I50 connect with the lead-in conductors I52 which may extend to the switch I64. For selectively connecting the elements I40 and I42 into the electrical circuit either in parallel, together or separately, or in series with each other to give high, low and intermediate heat, a contact drum I 54 is provided which may be in the form of a bushing of insulating material pressed over a metal core I56 which extends through the wall of the header I58 and has connected at the outer end a button I60 which may be manually turned to selectively rotate the drum I54. For placing the elements I40 and I42 within the electrical circuit suitably arranged contactor plates I62 are secured to the surface of the drum I54 which upon rotation of the drum I54 through the turning of the button I60 are brought into engagement with the spring terminals I40, I46 and I50 in their proper sequence to give high, low and medium heats. Preferably the conductors I52 have a suitable snap switch such as I64, as shown in Fig. 11, interposed between the terminals I50 and the electrical outlet so as to avoid any arcing that might result from the type of switch construction shownin Fig. 12 if the same were employed to make and break the electricalcircuit.

-It is to be understood that the construction shown in Fig. 1 is extremely simple and effective in operation and may be manufactured and marketed at relatively low cost. The control of the heating capacity-by the construction shown in Fig. 12 and the safety structure shown in "Fig. 11 may be included if desired but are not essential for successful operation of the heater.

I claim:-- '1. In an'air heater of the class described, an elongated air chamber through which air to be a heated is directed, walls at opposite ends of said chamber having recesses defined therein, air inlet and discharge passages defined in said walls and opening into said recesses, a carrier supported at opposite ends of said recesses and in said chamber having ridges defined on the surface thereof, said carrier and recess being so shaped as to direct the air flow along the outer side of said carrier and an electrical heating element imposed over and bridging said ridges so as to space the major portion of said element from the surface of said carrier and to dispose the same into the air stream through said chamber.

2. In the heater of the class described, a pair of end members having centrally disposed recesses therein, a carrier member having an electrical heating element supported thereon directly and axially supported from opposite ends in said recesses, an air inlet opening into one of said recesses and an air outlet opening out of the other of said recesses, means for directing air to and from said inlet and outlet, said carrier being removably supported, said carrier and recesses being shaped to provide openings directing the air flow substantially uniformly along the outer side of said carrier, and means supporting said end members in spaced relation and defining a chamber about said carrier.

3. In an air heater of the type described, an air inlet including a seat embracing the outer end of said inlet and adapted to receive an air chuck, means disposed over said seat, an adjustable clamp supported in said means and adapted to be brought into engagement with an air chuck to hold the same to said seat, an adjustment screw adapted to engage with the valve of an air chuck supported on said seat to open the same and regulate the amount of air admitted to the heater, and means supporting said adjustment screw for movement relative to said seat.

4. In an air heater of the type described, spaced end members, a central heating unit entirely and directly supported from said members,-a nonmetallic tube of insulating material embracing said unit in spaced relation throughout and defining therewith an uninterrupted tubular chamber, shoulder portions upon said members for supporting said tube independently of said unit, and an outer metal tube for spacing the said members and for holding said members and insulating tube in assembled relation, said insulating tube being relieved of all structural function by said metal tube and being shielded thereby, said insulating tube and unit being assembled and disassembled through relative spacing of said members.

5. In an air heater, the combination of a heating chamber, a conduit for conducting air under pressure into said chamber, means actuated by air pressure and moved from one position to another thereby, manually actuated switch mechanism, and means actuated by said switch and coacting with said first means resisting movement of said switch with said first means in one position and being ineffective to resist movement of said switch in another position.

6. A heater of the type described comprising a pair of separate vertical end members, centrally located axially aligned recesses defined in the inner opposed faces of said members, shoulder portions concentric with said recesses defined outwardly therefrom in said faces, one of said members having an air inlet opening through its wall into one of said recesses, the other of said members having an air outlet extending through its wall out of said other recess, an elongated electrical insulating core of substantially uniform cross section having its opposite ends directly engaging and supported in said recesses, said core having telescoping engagement within the recesses of said members whereby assembly may be efiected merely by axial displacement of said members, an electrical heating unit upon said core, an elongated heat insulating tube in which said core is concentrically located, said tube likewise having telescoping relation at opposite ends with said shoulder portions and assembled in the manner of said core, said tube forming with said core an elongated chamber of unobstructed uniform cross section into which said heat unit projects, said recesses and said core being shaped to provide air passages between the ends of said core and the defining walls of said recesses whereby the air flows uniformly along the outside of said core in entering and 15 leaving said chamber.

PAUL J. TIMBERLAKE.

Images