US2001068A - Portable heater - Google Patents

Description

4 Sheets-Sheet l uMay 14, 1935. J.' R. MacGREGOR vEr AL PORTABLE HEATER AFiled Aprjil 25, 1932 May 14, 1935. J, R. MacGREGoR ET AL 2,001,068 0 PORTABLE HEATER Filed Appil 25, 1952 4 sheets-sneer 2 Aiforney May 14, 1935, J R MMGREGOR Er AL- 0,001,068

PORTABLE HEATER Filed April 25, 1952 4 sheets-sheet 5 9 ...mwW

May 14, 1935- J. R. MacGREGoR Er AL. 2,00L068 PORTABLE HEATER Filed April 25, 1952 4 Sheets-Sheet 4.

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Patented May 14, 1935 UNITED STATES Pri'rslsrr oFFlcE PORTABLE HEATER John R. MacGregor, Albany, and Eldred E. Ed-

wards, Oakland, Calif., assignors to Standard Oil Company of California, San Francisco, Calif., a corporation of Delaware Application April 25, 1932, Serial No. 607,461

., p 2 Claims.

This invention relates to portable heaters which `may be `temporarily installed in compartments,

such as refrigerator cars, in which it is desired `to maintain air temperatures within certain nar- `row limits.` For example, when it is desired to `.transport lperishable foodstuffs during sub-zero weather, it has been the practice to use refrigerator cars for this purpose.

`is necessary in the cars under these circumstances 'and at intervals when access may be had to the No ice is used or doors of the cars,- portable Ycharcoal or coke braziers are used to bring the temperaturewithin the car above the freezing point of the produce being stored or shipped. Present heaters of this type `will continue to send out heat for several `hours after the supply' of additional fuel has beenshutvoff, due to the quantity of fuel which is necessary to support combustion, and which will continue to burn Vfor a long period of time.

It is well known that many foodstuffs are severely damaged not only by freezing but also by subjectiongto too high temperatures and the' procedure outlined above has been followed in an endeavor to prevent such damage by freezing.

` AIt is Well known that'such intermittent and uncontrolled `heating of the air within the cars does Vnot prevent over-heating at times when the burners are in operation and under-heating or freezing when the cars are in motion and access cannot be had to their interiors for long periods of time. This invention, therefore, consists of a small and readily portable heatern with a selfccntained source of fuel and accurate and positive safety and control devices to insure its safe 'and satisfactory operation. It willbe understood that this device is intended to maintain the air in a compartment, which may or" may not be a refrigerator car, at a closely controlled temperature above that of a lower surrounding or ambient4 temperature.

The requirement (Cl. 23e-so) vide an apparatus which will be safely operable by unskilled attendants.

Another object of this invention is to provide a space heater which is capable of maintaining a 'minimum temperature in the compartment in which it is located which will not vary more than two or three degrees from a given mean.

Another object is to utilize as fuel for the heater a hydrocarbon gas such as is commercially available in compressed or liquefied form.

Another object of this invention is to provide a regulating apparatus for a heater of this type which will automatically shut off al1 fuel supply in case the' pilot burnerY becomes extinguished.

Another object is to provide an apparatus which is adapted to be placed in or removed from a refrigerator car or similar structure without alterationto the car structure.

Another object of this invention is to provide a heater which will maintain its adjustment regardless of changes in altitude and consequent 'changes in atmospheric pressureupon its control mechanism.

Another object of this invention is to provide a portable heater which is adapted to be stacked.

for convenienc'eand economy in storage and transportation.

These and other objects and advantages of'this invention will become apparent from the following detailed description of preferred embodiment of this invention and its manner of operation, it being understoodfthat the invention is not limited to the arrangement specifically described.

' In describing this invention reference will be made to the accompanying drawings which form a part of this specification. In these drawings Figure l represents a vertical and 'part sectional View through a heater constructed according to this invention. for portableV and temporary heaters of this type is not limited to refrigerator Figure 2 represents a plan View of the apparatus shown in Figure 1.

Figure 3 represents a sectional detailed view ofthe safety shut olf valve.

Figure 4 represents a vertical sectional view through one form of thermostatic pilot valve control element and diaphragm actuated valve.

Figure 5 represents a sectional view through the thermostatic pilot Valve control element.

Figure 6 illustrates a plan View of an alternative form o-f thermostatic head for a pilot valve control member for the diaphragm actuated main valve.

Figure 7 represents a side elevation of the thermostatic head shown in Figure 6.

` transportation.

Figure 8 is a detailed section on line VIII--VIII of Figure 6.

Referring to Figures l and 2, the numeral II represents a fiat steel plate base of the general shape shown, provided with lifting handles I2 and hold-down devices i3 and 23.

The hold-down device i3 is fixed in position on the base l l. It utilizes a metal strap I4 which straddles a hole I5 through the base. A conventional toggle bolt l is arranged to move longitudinally in the sleeve i1, which latter is attached to the strap EG. The bolt l5 is urged upwardly when not in use by a helical spring I8, restrained between the bottom of sleeve I1 and an adjustable wing nut i9. A cotter pin through the top of bolt E5 prevents loss of the wing nut lil.

The pivoted head 2| of the toggle bolt It is adapted to be passed downward through the usual slotted iioor grating 22 of the refrigerator car, whereupon the bolt I6 is turned through 9S degrees and released. 'Ihe wing nut I9 is then screwed down on bolt I5 to seat on the top of .sleeve Il', holding the base securely against the iocr grating.

The other two hold-down devices 23, located at the opposite end of the base II are mounted to be horizontally adjustable, in order that they may accommodate various spacings of floor gratings 22, and also that they may be used in conjunction with ears or clips on the sides of a shield member, which will be described later, to hold a stack of heater units together during storage or Hold-down devices 23 on the tank end of the base Il are only different from hold-down device i3 just described by their being mounted upon a flat bar or strip 24 which is secured to the base plate II by a stud 25 and nut in such a manner that the hold-down devices may be moved about the stud as a center.

A pair of steel rods 21 are attached to plate I l by threading or welding and are fitted with an angle iron cross-piece 28, which latter is drilled and cut out to t over the neck of a lique'ed hydrocarbon storage tank or bottle 2S. Wing nuts 38 on the threaded upper ends of tie rods 21 serve to clamp the tank iirmly against the base plate l l. A sheet steel guard or shield 38 is attached to the base II and extends from one tie rod 21 around the burner and control apparatus to the other tie rod 21, thus protecting these elements and preventing radiant heat from being transferred to material immediately adjacent the heater.

Three bifurcated ears or lugs 3| are mounted on shield I3!! and a small supplementary shield lI8 which will be described later, as shown, and are adapted to receive the heads 2l of toggle bolts I 6 of the hold-down members i3 and 23, of a superposed unit during such times as the units are not in service and are stacked in tiers for storage or shipment. Base II is provided with arcuate cuts as shown adjacent to holddown members 23 to allow this to be done.

At the upper end of the tank 29 and attached to the conventional valve and union outlet 32, found thereon, is a metal conduit 33, preferably of seamless copper, which may be looped, as shown, to allow for movement in connecting and disconnecting. Conduit 33 leads to a conventional pressure reducing valve 34, which is provided with the customary adjustment handle |34 and an indicating pressure gauge 35. The pressure reducing valve mechanism is mounted on top of a standpipe or header 36 which is Welded or otherwise attached to the base I I, and is securely closed or blanked off at its lower end.

In the standpipe 36 and immediately below the outlet of the pressure regulator 34 is mounted a thermostatically controlled spring actuated safety shut off valve, generally designated as 31, which is designed to shut off the gas flow from the pressure regulator in case the pilot flame, to be described below, becomes extinguished.

Referring now to Figure 3 which shows the details of safety valve 31, it will be seen that this valve may utilize a conventional globe valve body 38, fitted with a guided valve plug 39, which is normally held from its seat by a coiled spring 40. A diaphragm 4I is clamped between the valve bonnet 42 and the top of the globe valve. An adjustable plug 43 screwed into the valve plug 39 may be moved relatively to valve plug 39 so that the allowable deflection of the diaphragm 4I is not exceeded during the maximum travel of the plug 39 from its open to its closed positions.

A metal frame or bracket 44 extends axially from the valve body 38, and is fitted with a pin 45, which forms the bearing of a bell crank 46, one end of which rests on the top of the diaphragm 4I. The other end of bell crank 46 terminates in a pin 41 which extends at right angles to the main body of the bell crank. A bimetal strip 48 is provided at one end with a bearing 49 which encloses pin 41. The other end of the bimetal strip 48 terminates in a hinge 53 provided with a pin 5I. A metal strip 52 is provided at one end with a loop which forms the other half of the hinge 50. Strip 52 is tted near its midpoint with a loop 53 which ts over a pin 54 at the outer extremity of the bracket 44. Strip 52 is bent, as shown, and is provided with an extension or seating handle 55.

It will be seen that bimetallic element 48 and strip 52 form two parts of a hinged toggle which is illustrated in its actuated or collapsed position. In this position it will be noted that spring 56 will move bell crank 4G to close the valve member 39 upon its seat.

Bimetallic element 48 is bent to be concave outwardly as shown and with the metal having the higher co-eflicient of expansion on the concave side. Thus, when it is cold, bimetallic element 48 will press against the adjustment screw 51, making it impossible for the toggle to remain straightened unless it is held in that position by means of extension 55.

To open valve 31 and allow gas to flow therethrough, handle is moved clockwise about pin 54, thus moving hinge 58 toward bracket 44 and straightening the toggle against the stop screw as just described. It is held in this position until heat from the pilot burner, to be described later, bends the bimetallic element 48 to be concave inward or toward the stop screw 51, allowing the hinge 50 to reach a point past the straightened position of the toggle. As long as heat is supplied to bimetallic element 48 the hinge 5G will remain in this position, element 48 being then concave inwardly or around the stop screw 51. If this heat should fail due to the pilot ame becoming extinguished, the biinetallic element will move the center hinge 58 of the toggle upward beyond its straightened position allowing the toggle to collapse and causing the bell crank 46 to move under the influence of its spring 56 to close the valve plug 39 against its seat. lt will ce noted in Figure 1 that the safety valve 31 is so mounted that heat from the pilot burnel1 is directed against bimetallic member 48.

Referring again to Figure 1, it will be seen that immediately below valve 31 is a T connection 58 from which a tube 59, preferablyof seamless copper, leads to the pilot valve control element of a gas pressure actuated main valve generally "designated, 5 9,

One form` of a main valve assembly 69 is shown in Figure 4 and will now be described. It consists of Aa conventional globe Valve body 6I provided with a small diameter raised ring seat 92. A soft metal or composition valve disc 63 is adapted to seat onfthe ring 52, and is mounted at the lower end of a guide plug 64. The bonnet 95 of the v alve is adapted to clamp over a flanged sleeve 66. Between the face of the flanged mem- `ber 96 and the top of member 9| is clamped a diaphragm 51 which prevents gas leakage around the stem 69 of the guide plug 64. A recessed plate 69 is mounted on top of member 69 and forms the lower half of a main diaphragm chamber, and

also a support for the pilot valve mechanism. A

valves 14 and 15 lare mounted in threaded plugs 18 and 19 respectively, which plugs are provided with small longitudinal passages 89 and 8|, for a purpose which will be explained below. A threaded cap 82 normally covers the needle valves 14 and 15 and may be removed for adjustment of these valves. This cap communicates with a conduit 83 leading to the pilot burner, which will be described later.

Conduits 89 and 95 lead from the upper and lower cavities of the diaphragm chamber formed by diaphragm 1| with members 69 and 10 to orices 86 and 81Y respectively (Figure 5) of the thermostatic pilot valvernech'anism. These orices are mounted in the lower part of a tube 88, which is provided at its lower end withra'slotted stop member 89 and a closure cap 99.

At the upper end of tube 98 is mounted a flange 9| on which a second flange 92 is held by means of suitable screws 93. Surrounding ilanges 9| and 92 is a tubular sleeve S4 which extends upwardly. A short distance above the top of flange 92, and extending through sleeve 94 is a hinge pin 95 for the thermostatic element and pilot valve mechanism.`

This mechanism consists of a rod 99 which extends from a point near the upper end of sleeve 99 downward to a point neartheforices B5 and 91. Where it passesinto tube 93 itis sealed by means of a diaphragm 91, which is clamped between flanges 9i and 92.*The lower end of rod 96 is slotted to receive a flat strip 98 which eX- tends downwardly into the stopI member 89 whose slotted opening limits the motion of strip 98 about the pin 95. On member 98 `and directly opposite the'opening of the opposed orifices 86 and 81 is mounted a soft rubber or composition valve seat 99, which is adapted to close either orifice 89 or B1, depending upon which way the rod 95 is moved about thehinge pin 95. i

Attached to rod 95 at itsconnection withpin 95 is a block 99 which may be lclamped to both the rod 96 and pin 95 by means of suitable screws. B imetallic strips 19|, |92, |93 and `IIlllare attached to block |99 and extend upwardly therefrom.

` valve E9, by means of conduit I i I.

Strips |9I- and |92, which are nearest to rod 95, continue upward above it and are clamped be'- tween'adjusting nuts |95 on a threaded rod |99, which passes through `the top of tube 99. At a point opposite the upper end of strip |94, spacer blocks |91 are soldered to |93, |92 and I9I respectively, on one side only, so that |99 is free to slide relatively to the block on 93, |53 is similarly free at this point to slide relatively to |92 and so on. A clip |98 passes around all the bi-metallic strips at this point asv shown, and serves to keep them in slidable contact. In this way'the forces at this point tending to bend the strips in either direc- `tion are accumulated and transmitted to the block |99 without lost motion or friction.l similar arrangement of spacer blocks |91 and clip |98 is provided for the elements E99, 92 and I9I at the point opposite theupper end of strip |99. At the upper end of strips i9| and E92 but one spacer block |91 is required, soldered to either IUI or |92 and free to slide on the other.v The adjusting nuts |95 here take the place of clip E99.

In this way the entire thermostatic element may be made of such shape that'it will approxi# mate a constant strength beam and will respond with maximum force to changes in temperature. In the example shown the material having a higher expansion coeicient is located on the side farthestfrom rod V99.

AOne side of sleeve 94 is cut away shown atV |99 to allow free access of air to the bi-metallic elements IDI, |02, |93 and IBA. Rod 99 extends upwardly from block 99 almost to the end of the f longest bi-metallic elements in order to provide counterweight for the lower portion that extends into tube 98. It is desirable to have diaphragm 91 as close to the center of the hinge pin 95 as possible for this diaphragm must absorb a small amount of lateral distortion due to oscillation of the rod 96 about the pin 95, and the shorter this distance, the less strain on the diaphragm.

By referring again. to Figure l it will be seen that a second T connection H9 leads from the gas standpipe or main 36 to the inlet of the main A conduit I l2 leads from the outlet of valve 59Yto a burner I E3, which may be of the conventional Bunsen type, and which is mounted on a suitable bracket IIA within a suitable metal shield or chimney IE5. Chimney |15 is provided wth a number of holes, as indicated, below burner l I3, to` allow access Vof air for combustion. Holes may be provided in the base II directly below the chimney H5 and the holes in the chimney omitted in cases where the heater is to be used over a `grated floor, as by this means circulation of the surrounding air is provided by the formation of convection currents which aid in evenly distributing the heat.

It has been found that the ordinary Meeker type burner is preferable to use as the main source of heat. Any equivalent burner which is not seriously affected by changes in air-fuel ratio may be main burner II3. The tip of pilot burner H6 may be of any desired shape but it has been found that a rather narrow slot with its edges somewhat lower than the end of the pilot burner gives very good results.

The pilot burner H9 is preferably enclosed by means of a small covered sleeve or shield Il'l attached to the inside of chimney I l5 as shown. A hole approximately opposite the top of main burner H3 is provided through this shield to allow gas from the main burner to reach the flame of the pilot burner and become ignited therefrom. It will be noted that an opening is cut in chimney H5 immediately above the pilot burner H6 to allow the bi-metallic element 48 of the safety shut-off valve 9? to project therethrough and be exposed to the heat rising from the pilot burner. Shield lil also serves to protect this vbi-nletallic toggle member from excessive radiation from the flame of the main burner H3.

An auxiliary perforated shield H8 outside of main shield E99 is provided around the thermostatically operated pilot valve mechanism described above, to prevent its damage or derangement from handling or transportation. The perforations of this shield should be such that free access of air is allowed to the thermally responsive element at all times. The combination of shields 39, H5 and H3 prevent drafts from blowing out the two burners, protect the burners and control equipment from mechanical damage, protect the cargo immediately surrounding the heater unit from excessive radiant heat, and protect the thermally responsive control elements from radiation from the main burner, which otherwise would cause it to function without relation to the temperature of the air in the compartment.

In operation, the valve 32 at the top of the storage tank or bottle 29 is opened, allowing gas to flow through conduit 33 to the pressure reducing valve 94. This may be adjusted to reduce the gas pressure to five to ten pounds per square inch by adjusting the handle l 39 Until the desired reduced pressure is indicated on the gauge 35. The handle of the bi-metallic toggle mechanism on safety valve 3l is then moved to straighten out the toggle as described above, and allow valve member 39 to open under the impulse of its internal spring 49. This allows gas to ow into conduits 59 and Hl, thence into the interior of tube 88 and to the inlet of main valve 69 respectively.

Assuming that the temperature of the atmosphere in which the apparatus is located is below that which it is desired to maintain, the bi-metallic elements il, 62, |93 and E94 will have bent to cause the rod 96 to move in such manner that orifice 86 will be closed by the pilot valve member 99, and orifice 81 will be open. This condition will allow gas from conduit 59 to pass into tube 99, Where it is prevented from escaping by diaphragm 91, through orice 8l and conduit 95 to the lower cavity of the diaphragm of main valve 69. From this chamber a small stream of the gas will flow through passage i6, past needle valve 'M and through passage 89 into the chamber S2. From here it will ow through conduit 83 to the pilot burner H6, where it may be lighted by a match or other source of flame.

The gas which may be present in the space above diaphragm 1i of the main valve 69, will leak out through passage Tl, past needle valve 'l5 and passage 8| to the chamber 82 which is at practically atmospheric pressure. This will allow the excess pressure of the gas below diaphragm H to urge the diaphragm upwardly, thus lifting the pilot valve member 99.

valve 63 from its seat 62 and allowing gas to pass through valve and conduit ||2 to the main burner H3. As the pilot burner H6 has already been ignited, the gas from the main burner H3 will be ignited therefrom, and will continue to burn as long as the temperature in the compartment is below that for which the bimeta-llic elements IUI to |94, have been adjusted. This adjustment may readily be secured by means of nuts |95 at the upper end of the elements.

It will be noted that the gas supply to the pilot burner H6 is uninterrupted by this action of the thermostatic pilot valve control mechanism, as gas flow exists through either orifice 86 or 81 and consequently needle valves 'I4 or 'i5 at all times. The heat from the pilot b-urner i E6 maintains the loi-metallic toggle 49 of safety valve 31 concaved inwardly so that Valve 39 remains open. Should the pilot iiame become extinguished from any cause, the toggle element 48 will bend to its opposite position as shown inrFigure 3, thereby shutting off the gas.

It will be apparent that the orices 96 and 97 are of appreciable area, and that when either is covered by the valve member 99, a force approximately equivalent to the pressure in the tube 89 over this area holds the valve member 99 rmly seated. When the temperature in the storage compartment tends to cause a reversal of the position of valve element 89 by bending the thermostatic elements IUI to |84, sufficient work must be stored in the deflection of members 99 and IDI to |94, to overcome this force. When suflicient work is thus stored, rod 96 is quickly and positively moved to its opposite position where it remains until the action is reversed.

It will be apparent that the construction of the main Valve 69 may be varied from that just described; for example, one of the operations of diaphragm 'Il could be performed by a spring arranged to either open or close the valve 63.

This would mean a construction in which but one orifice would need to be controlled by the thermostatic Valve mechanism, and particularly Y An advantage to this type of construction would be that such a control mechanism could be arranged that the soft pilot valve member 99 was only in contact with its single orice during such period as the gas supply was to flow through the main valve 69. This would relieve the wear on pilot valve member 99 and permit it to remain in good condition for a long time. Furthermore, there would be no requirement of storing work for both the opening and closing actions of the thermostatic pilot valve mechanism, thus allowing closer adjustment of temperature control. Many modifications of the valve seat 62 and valve disc 63 of valve 69 could also be made, in the interest of simplicity and cheapness.

Referring now to Figures 6, 'l and 8 which show an alternative form of the bi-metallic elements previously designated I9! to 94 of the thermovstatic pilot valve mechanism. The tube 83 of Figure 8 is of substantially the same construction as that shown in Figure 5, except that it can be made considerably shorter. The anges 9| and 92 are also as previously explained. A similar diaphragm 91 may be used to seal off the chamber within tube 88 from gas leakage. The rod 96 is arranged to oscillate about a pin or spindle H9 Whose axis is at right angles to the axis of rod 99, and which passes through flange 92 as shown in Figure 8. A bracket |29 is attached to one side of ange 92 as shown in Figure 6. Bracket |20 is fitted with two loi-metallic element support spindles |2| and |22. These are adjustably and rotatably secured within key hole slots |23 and |24 in bracket |20 by means of clamping bolts |25.

Attached to spindles |2| and |22 are spiral strips of 'pi-metallic elements |26 and |21 respectively. These spirals are wound in the same direction and are of the same effective lengths but are mounted i3() degrees apart. These spirals are provided near their outermost ends with notches |23, in which are received the opposite ends of a pointed lever |29. Lever |29 is rigidly mounted on spindle l I9 which, in turn, is rigidly connected to rod 9% as outlined above. l

Changes in temperature of the two bi-metallic spirals E26 and |21 result in force being exerted upon the opposite ends of lever |29 tending to rotate it about the center of spindle H9. This rotation of spindle HS is transmitted to rod t and results in a displacement of its lower end, which actuates the pilot valve element` S9 to open or close the orice or orifices at the lower end of tube Sii. As the bi-metallic spirals |26 and |21 are mounted |83 degrees apart they will exert their forces in opposite directions and their re- `spective expansions and contractions will assist the other in moving the opposite ends of lever |29 with the maximum force available. This construction results in a couple which is in unstable equilibrium and which will assume a position at either one or the other end of its travel, thereby insuring positive action of the pilot valve member 99.

While these two modifications of bi-metallic elements have been described it will be apparent to a height of eight or nine thousand feet above sea level, as may occur when the apparatus is transported from the llacific Coast to the eastern part of the United States. If such diaphragms and the like are suitably compensated for changes in barometric pressure they could readily be adapted for this purpose.

Although a specic construction embodying this invention has been described and illustrated, it is to be understood that the invention is not limited to that specific device and all such modiiications and changes as come within the scope of the appended claims are embraced thereby.

We claim:

l. Apparatus for controlling the flow of gas to a portable heater having a main and a pilot burner, comprising a main valve body, a valve in said body, a diaphragm adapted to move said valve, a single valve means for admitting gas pressure to either side of said diaphragm, thermally responsive means for controlling said last named valve, and restricted passages from both sides of said diaphragm to release gas pressure thereon, said passages being unaffected by the position oi said last named valve means and adapted to supply gas to the pilot burner.

2. Apparatus for controlling the flow of gas to a main and a pilot burner, comprising a valve in the fuel gas supply to the main burner, a dia phragmchamber having a movable diaphragm for actuating said valve, said diaphragm dividing said chamber into upper and lower cavities, a control valve chamber communicating with the fuel gas supply, separate conduit means leading from said control valve chamber to said upper and said lower cavities in said diaphragm chamber, separate outlet passages from said cavities to the pilot burner, a single valve in said control valve chamber, and thermostatic means adapted selectively to move said last named valve to open one of said conduits and to close the other of said conduits, whereby said diaphragm and the valve connected thereto are positively Vmoved from one to the other of their extreme positions.

JOHN R. MACGREGOR. ELDRED E. EDWARDS.

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