US2215768A - Heater - Google Patents

Description

SQPL 24. 1940? c. A'. RICHARDSON 2,215,768

HEATER OriginalA Filed April 13, 1939 3 SheefS-Sheet 1 @may f [Mmm/wy c. A. RICHARDsoN asuma original Filed April 1s. 19:59 s sheets-sheet 2 Sept. 24, 1940.

HEATER l Original Filed April 13, `1939 3 Sheets-Sheet 3 wm mm A {income/25 Patented Sept. 24, 1940 PATENT OFFICE- HEATER g Chester Af Richardson, San Francisco, Calih original application April 13,Y 1939, serial N. 261,698. Divided mi this appli-mien .my 24,

1939, Serial No. 286,229

zclaims.' (c1. 15s-94) This invention relates to heating devices, and particularly to the heaters used in the ice bunkers ofl insulated refrigerator cars during winter months to hold the temperature in the car at a 5 safe value.' The present application is a division Y of my application Serial No. 267,698 iiled April Heretofore uncontrolled charcoal heaters have been the chief reliance and for certain classes of i0 service are satisfactory. There is, however, an

active demand for a heater including some automatic temperature controlling means. To secure such control, the most practical fuel 4is a liquid fuel. Obviously it must be one whose l5 products of combustion are not objectionable, either from the standpoint of danger to service men, or-from the standpoint of injury to fruits Vand vegetables.

For the past several years extensive tests have 90 been conducted in an effort to produce a reliable thermostatically controlled heater. The fuel chosen has been alcohol, because it seems to meet1 l better than any-other fuel available, the requirements above outlined.

25 The importance of close temperature regulation cannot -be overstated. Certain classes of fruit should be held within the range of only a rfew Fahrenheit degrees, otherwise their keeping qualities will. be seriouslyV impaired. Slightly l .o greatervariations will result in rapid destruction. For-example, the permissible range with apples is small, particularly if they have been in cold storage. The temperature for bananas which are not to be ripened in transit must be I5 held wit-.nin close umiis and the temperance is higher than that required for apples. The desired temperature for bananas which are to be ripened in transit is still higher. It follows that a heater suited for general use must be capable 0 of a wide variation of heat output, must be controlled in response to temperature within rather narrow limits, and must include a temperature controlling means which may be set for a wide range of different temperatures and control 5 within-close limits at each setting. The adjustment should be easy to make, accurate and capable of accurate indication. This, of itself, produces a very difficult Vcontrol problem, while the design of a burner which will perform eiliciently over a wide range of heat outputs is a problem'in itself.- y t A For satisfactory regulation, the best scheme for controlling the heat output is to use an any nular asbestos wick burner having a maximum capacity suiiicient to supply the maximum. demand, in conjunction with a .controller which turns the supply of alcohol to the wick on and oi in response to a small temperature change. To permit control of such a burner to the point e of extinction it is necessary to use afpilot light, preferably also of the asbestos wick type. The pilot burner furnishes only a negligible amount of heat and will light the main burner wick as soon as fuel is supplied thereto. l@

In the operation of refrigerator cars, itis necessary to open the hatches over the bunkers for inspection purposes, and on windy days this is likely to result in extinguishing the pilot light. Even in calm weather the slamming of the 35 hatches closed will put out any but a well protected pilit light. The violent slack action often encountered in freight trains also imposes severe requirements. The situation is one in which a very high standard of performance and reliability is required under conditions so variable, and frenquently so adverse, that the problem of developing 'a completely satisfactory heater has proved baffling.

As a result of the use of a float controlled feed to bothl burners in conjunction with a thermostatic control of the feed to the main burner, a heater was devised by others which operated very successfully under favorable conditions. Basically it was sound, but it could not withstand a@ adverse conditions with suflicient certainty to bel commercially adopted as it stood.

The inventions covered by the parent application and this division thereof relate to ancillary features and improvements which have made it possible for this general type of burner to meet the very severe conditions encountered in service.

One feature of novelty forming the subject matter Vof this divisional application is protection of the pilot light in such a way that it is 'w virtually impossible to blow itout. To accomplish this result, recourse was-hand to two more or less related arrangements. One is a sheltering chimney, with protecting cap which protects u i the pilot burner, andat the same time offers an opening whichpermits the pilot to light the main burner with certainty. 'I'he lighting communication with the main burner, however, subjects the pilot flame to the possibility of being blown out, '50 for the reason that a passage large enough for the communication of name is large enough for the communication of an extinguishing draft.

To meet this situation, the pilot burner flame is sub-divided into two semi-distinct parts, one l of which is adjacent the ignition opening and the other of which is so isolated from the ignition opening that it cannot ignite the main burner but will re-ignite that portion of the pilot burner which is adjacent the ignition opening if this portion should beblown out. ll'he use of a subdivided pilot flame has eliminated almost y completely the very troublesome burner failures which were a source of trouble previously.

AAnother feature of novelty reserved for the parent application is the usev of a series of concentric tubes forming concentric annular ducts in which air ow occurs. These ues protect the encircling alcohol reservoir from undue heating, and apply the heat usefully to a part of the air circulating through the stove.

l Another important feature involved directly in the parent application and to an extent in this present divisional application is the use of screens which on the well known principle of the miners lantern, prevent the passage of flame without preventing the flow of air. These screens are, one within the annular main burner, i. e., between it and the pilot light, except at the ignition opening, and the other outside the main burner. The first of these gives shelter to the pilot light and evens the draft on the inner side of the main burner. The second by serving as a heat conducting and diffusing grid, delivers heat to the rising current of air and resists passage of heat from the burner to the thermostat which last is mounted within the base of the heater.

It would be desirable, if practicable. to mount the thermostat outside the heater so as to respond directly to the temperature of air in the car, but for .obvious reasons this is' not possible. Accordingly, it is necessary to mount the thermostat in the base of the` heater structure where it is affected by air entering the heater and, consequently, operates substantially at car temperature.

The outer screen above-mentioned protects the thermostat from stray heat from the burner and has been demonstrated to contribute very greatly to accurate temperature control of the heater. It also evens the draft and improves the delivery of heat usefully to the circulating air.

An insulating baille is provided to protect the thermostat from direct heat radiation from the burner, without, however,impairing the circulation of entering air in contact with the thermostat.

The various features above-mentioned are inter-dependent in a considerable degree and pro- 'duceasuccessflxlheaterthatissubstantiallyprotected against accidental failure. Success has been attained by very close coordination of the various features above pointed out.

'Ille invention will now be described-with reference to the accompanying drawings which show a commercial embodiment of the invention which hasbeen usedin actualserviceunder clo .observation and has demonstrated that it satis factorily solves the problem Y In the drawings: Y

Pig. iisasldeelevationofthecompleteheattoshowtheinternalconstructionof members il.

which they cunjomuy conn-o1' the Fig. 5 is an enlarged perspective view of the llame divider used on the pilot burner.

Heaters of the type described herein are temporarily placed in the icebunkers of insulated refrigerator cars at times when no ice is used and the cars are subject to external winter temperatures. To hold them in place and prevent their upsetting and causing fir, they are held in place by chains, following the practice heretofore used with charcoal heaters.

The main supporting framework of the heater comprises a cylindrical base 6 to which is -welded an upwardly dishedported bottom 1. Near the upper margin of the base 8 is a circumferential bead 8 which serves as a shoulder to assist in positioning the upper Cylindrical shell 9 of the heater. This is circumferentially corrugated as shown in the drawings, the purpose of the corrugations being to stiften the cylindrical shell. A reinforcing band II encircles the top of upper shell 9, and a lifting bail I2 is hinged near the top of the shell, so that it may swing down with in the upper margin 'of the shell as clearly indiu vtwo open-ended cylindrical sleeves, an outer sleeve i5 andra slightly longer inner sleeve I i. The inner sleeve is the chimney tube, the outer sleeve has a heat insulating and dissipating function, and preferably comprises a core of sheet asbestos covered on both faces with a layer of thin sheet metal. Such an arrangement is indicated in Fig. 1. The asbestos core may be omitted, in which case sleeve Il would be simply a metal tube. l

`The sleeves l5 and I6 are'sustained and held centered by radial connectors whose form is best shown in-Flgs. 1 and 3. Near the bottom of the sleeve I5 there are four stirrup members I3 and near the top of the same sleeve are four radial spacers Il. Opposite ends of these members I3 and Il are connected to the sleeves l5 and Il and to the outer shell l by meansof bolts i1 `whichpassthrough tubularspacers I8 as clearly indicated in the drawings.

An annular fuel tank i9 Vishmoimted in the interval between the outer sleeve II and the shell-tit isspaced fromtheshell i5 to afford a vertical air passage. It rests on the stirrup irons I3 and is removably retained by the radial It has a filling opening withl cap llisee Figs. 1 and 3);

Beside rendering the fuel tank removable, this construction protects the fuel tank from overheating and applies usefully heat from the burner vto Stimulate air circulation The intervals between the sleeves II and ii and between the sleeve Il and the inner-wall of tank i9 develop a decided chimneyedect, promoting the circulationbf airY through the heater, and this active circulation causes the thermostat to respond more nearly to the'actual .temperature in the The main burner is mounted in the lower or Vhase section l andcomprises an annular trough 22 supported by legs 23 and heat insulating spacers 26 on -the lower head 1. The annular troughintheburne1.containss porousbrous incombustible wick 25 which in practice is made of asbestos. It is held above the bottom of the trough by a zig-zag spacer 26. Extending from the outer margin of burner 22 at the top thereof is a foraminous baille or screen 26 which extends outward and downward to the lower margin of the chimney I6, to which it is rigidly attached. 'I'he purpose'v of this screen is two-fold. It regulates the iiow of ,air to the chimney outside the burner and it is kept cool by the up-ilowing air, so that it serves effectively as means to resist passage of heat from the burner downward to the thermostat, and to the oat chamber hereinafter described.

Concentric with and.. mounted within the burner 25 is a foraminous screen or baiile 21 which extends upward a substantial distance above the burner and which is closed at its upper end by a cap 26. This cap is imperforate except for an opening to receive the pilot light chimney 29 winch extends through the cap 26 and which is connected to the baille 21 as indicated at 3|. The cap 28 is held by a'bolt 32 which is attached at its lower end to a portion of the framework of the burner 22. A third screen name as extends horizontally across the space within the baiile 21 and approximately at the upper margins f 3 in the annular main burner 25 and tangent thereto. It is of the incombustible wick type and is located adjacent to an ignition opening 36 formed in the` foraminous baille 21 and intended as to permit the transfer of flame from the pilot burner to the main burner. Opposite thisv opening and extending across and dividing the pilot flame is a dame divider or baille 36 whose form is best shown in Fig. 5. The divider rests on the top of the wick and has a notch 30 for the transmission of illame. The divideris carried by a sleeve which slips onto the upper margin of the pilot burner shell.

The upper end of the pilot chimney is closed by a hinged cup-like cap 31 formed as shown with an umbrella-like baille 31a to offer additional protection against back drafts.

I The upper end of the main chimney sleeve I6 is closed by perforate hinged cap or baille 36. This cap 38 offers important protection against the blowing out of the burner. I'he openings whose form `and arrangement are best shown in Fig. 3 are designed to give adequate circulation, and at the same time to afford the maximum possible protection against back-drafts such as occur when the car bunker doors are opened or when these doors are slammed shut.

Air for combustion and air to be heated by the stove enter through lateral openings 39 in the base section 6. The combustion air ilows through the screen bafiles 26 and 33 to the combustion zone and thence upward through the chimney I6. Other air, however, flows upward through the annular passages aroundv the tank I 9 and between the chimney I6 and the sleeve I5.

55 This air is heated in greater or less degree and thus serves two usefulpurposes', i. e., the delivery of heat to the car, and the protection of the fuel tank against over-heating.

Mounted within the base portion 6 outside th 7 0 main burner 25 is the float valve mechanism indicated by the numeral 4I applied to its housing and the thermostat indicated by the numeral 46 applied to its body. The function of the-float valve mechanism is to maintain a constant level 75 of fuel supply for both burners. It maintains a uniform level in housing 4i and from this chamber alcohol is fed at all times through the connections 42 to the pilot burner 34. Thus this burner operates continuously with fuel supplied at constant level.

The float chamber 4I also supplies fuel through the connection 43 to the main burner 25. This connection is not constantly open but is opened variably and at times closed by a valve indicated at 44 in Figs. 1 and 3 and subject to control by 10 the thermostat 40.

With this general explanation of the organization of the fuel control, reference will n ow be made to Fig. 4 in which the fuel control mechanism is shown in greater detail. I6

Fuel is led from tank I9 by pipe 45 to body 4I enteringthrough fiilter cartridge 46 which is sealed in a chamber 41 by clamp 46. From chamber 41 the fuel rises through tube 4 3 which contains the seat for needle valve 5I, and enters 20 floatchamber 52. The needle valve is actuated by float 53, pivoted'at 54 and counterweighted at 66. The eilect is to maintain fuel inchamber 52 at the level A-A.

Connection 42 leads from the bottom of cham- 2 5 ber 62 to pilot burner 34.

Connectionv 43 communicates with chamber 66 in the lower portion of body 4I, and fuel flows from chamber 62 to chamber 56 under the control of needle valve 44 which is actuated by lever $0 51 of the thermostat through rod 56. The shell or'housing 40 of the thermostat is the expansible element and is madeof aluminum. The neutral velement comprises two spring bows 66, 6I composed of an alloy sold under the trade 65 name Invar. This is an iron nickel alloy and has a negligible coemcient of thermal expansion. Thus the bows approach each other in responseto falling temperature. I

Lever'61 is pivoted to bow 66 and bow 6I reacts 4o against the lever through the adjustable thrust screw 62 which has a graduated milled head 63. An index 64 indicates the adjustment and a spring detent 66 (see Fig. l) preserves the adjustment. The parts are so arranged that fall- 45 ing temperature tends to open the valve.

Since screw 62 acts on the lever 51 in one way thrust in a valve opening direction, the weight of the parts acts to close the valve and the parts can never be over-stressed. Adjustment of head 60 63 merely changes the temperature at which the valve starts to open. It reaches full capacity with very slight lift, so that the control is sharp, approaching a simple on and oil' action, rather than graduated opening and closing since such graduation as occurs is within a very-small temperature range.

A baille 50 of heat insulating material protects the thermostat from heat radiating directly from the burner. A 60 No novelty is here claimed for the structureof the float valve per se or for the structure of the thermostat. The thermostat has the desirable characteristic for car service of being little aiect- Ied by vibration. The double bow arrangement 65y gives a pronounced motion multiplying action, so that small temperature changes produce substantial valve motion at the control point.

While the devlceshas been described in cons siderable detail and while certain of these de- 70.

What is claimed is:

i. In a heater, the combination of a main burner having a fuel basin and a wick mounted therein; a pilot burner mounted adjacent the main burner; a foraminous screen for protecting the burners and having an ignition opening through which flame from/the pilot burner may pass to the main burner; means for turning on and ofi vthe supplyof fuel to the main burner; and a baille mounted above the pilot burner arranged to subdivide partially the iiame of the pilot burner, whereby the pilot burner is protected against complete extinguishment by draft through said ignition opening.

2. In a. heater, the combination of a main burner having a wick; means for turning on and oi the Supply of fuel to said wick; a, pilot burner adjacent the main burner and arranged to ignite the same; flame shielding means at least partially separating the flames of said burners but arranged to aiford means for the 5 transfer of flame from the pilot burner to the main burner; means for supplying fuel continuously to the pilot burner; and means for subdividing the iame of the pilot burner whereby portions of the pilot burner flame vare protected 10 from extinction by drafts while permitting transfer of flame from the pilot burner to the main burner, and between the subdivided portions of the pilot ame.

CHESTER A. RICHARDSON. l5

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