US2215767A - Heater - Google Patents

Description

1*- 1940' c. A. RICHARDSON HEATER a Sheets-Sheet 1' Filed April 13, 1939 Inventor (39mm CLIR/Lcha/zb w w (Ittomegs p 2 c. A. RICHARDSON 15 Y HEATER Filed April 1:5, 1939 3 Sheets-Sheet 2 Zinnentor Gttor negs Sept. 24. .940. c. A. RICHARDSON 6 1 msmm Filed April 1a,. 1939 3 Sheets-Sheet s Zinnentor attorneys in cold storage.

t Sept-- 24, 1940 UNITED STATES PATENT OFFICE 2,215,767 mia'rnn Chester A. Richardson, San Francisco, Calif.

Application April 13, 1939, Serial No. 267,698 2 Claims. (01. 126-96) This invention relates to heating devices, and particularly to the heaters used in the ice bunkers of insulated refrigerator cars during winter months to hold the temperature in the car at a safe value.

Heretoi'ore uncontrolled charcoal heaters have been the chief reliance and for certain classes of 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 is a liquid fuel. Obviously it must be one whose products of combustion are not objectionable, either from the standpoint of danger to'service men, or from the standpoint of injury to fruits and vegetables.

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

The importance of close temperatureregulation cannot be overstated. Certain classes of fruit should be held within the range of only a few Fahrenheit degrees, otherwise their keeping qualities will be seriously impaired. Slightly greater variations will result in rapid destruction. For example, the permissible .range with apples is small, particularly if they have been The temperature for bananas which are not to be ripened in transit must be held within close limits and the temperature 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 of a wide variation oi 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 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 diflicult control problem, while the design of a burner which will perform ef-' flciently over agwide range of heat outputs is a problem in itself.

For satisfactory regulation, the best scheme for controlling the heat output is to use an annular asbestos wick burner having a maximum capacity suificient to supply the maximum demand in conjunction with a controller which turns the supply of alcoholic the wick on and off in response to a small temperature change.

preferably also of the asbestos wick type.

the other of which is so isolated from the igni- To permit control of such a burner to the point of extinction it is necessary to use a pilot light, The pilot'burner furnishes only a negligible amount of heat and will light the main burner wick as soon 5, as fuel is suppliedthereto.

In the operation of refrigerator cars, it is 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. '10- Even in calm weather the slamming of the hatches closed will put out any but a well protected pilot light. Theviolent 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 frequently so adverse, that the problem of developing a completely satisfactory heater has proved bafliing. m

, As a result of the use of a float controlled feed to both 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 adverse conditions with suilicient certainty to be commercially adopted as it stood.

The present invention relates 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 the invention is protection of the pilot light in such a way that it is virtually impossible to blow it out. To accomplish this 35 result, recourse was had to two more or less re- Y lated arrangements. One is a sheltering chimney, with protecting cap whichprotects the pilot burner, and at the same time offers an opening which permits the pilot to light the main burner with certainty. The lighting communication with the main burner; however, subjects the pilot flame to the possibility of being blown out, for the reason that a passage large enough for the communication of flame 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 of which is adjacent the ignition opening and tion opening that it cannot ignite the main burner but will re-ignite that portion of the pilot burner which is adjacent the ignition openportion shouldbeblown out. The use most completely the very troublesome bm'ner failures which were a source of trouble previously.

Another feature of the invention is the use of a series of concentric tubes forming concentric annular ducts in which air flow occurs. These fiues protect the encircling alcohol reservoir from undue heating, and apply the heat usefully to a part of the air circulating through the stove.

Another important feature is the use of screens which on the well known principle of the miner's 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. I'he 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 baflle is provided to protect the thermostat from direct heat radiation from the burner, without, however, impairing the circula tion of entering air in contact with the thermostat.

The various features above mentioned are inter-dependent in a considerable degree and produce a successful heater that is substantially protected against accidental failure. Success has been attained by very close coordination of the various features above pointed out.

The invention will now be described with reference to the accompanying drawings which show a commercial embodiment of the invention which has been used in" actual service under close observation and has demonstrated that it satisfactorily solves the problem.

In the drawings:

Fig. 1 is a side elevation of the complete heater partly broken away in section to show the internal construction. 7

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is a partial plan view of the complete heater.

Fig. 4 is a developed view on line 4-4 of Fig. 2, designed to show the internal construction of the float valve mechanism, the internal construction of the thermostat, and the connections by which they conjointly control the supply of fuel to the main burner.

Fig. 5 is an enlarged perspective view of the flame divided used on the pilot burner.

Heaters ofthe type described herein are temporarily placed in the ice bunkers of insulated refrigerator cars at times when no ice is used and the cars are subject to external winter temtheir upsetting and causing fires,

peratures. To hold them in place and prevent 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 dished ported bottom 1. Near the upper margin of the base 6 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 stiffen the cylindrical shell. A reinforcing band ll 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 within the upper margin of the shell as clearly indicated in Fig. 3.

The perforated ears indicated by the numeral III in Figs. 1, 2 and 3 are provided for the attachment of the chains abovejnentioned, but not shown in the drawings.

Mounted concentrically within the shell 9 are two open-ended cylindrical sleeves, an outer sleeve I5 and a slightly longer inner sleeve IS. 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 15 would be simply a metal tube.

The sleeves l5 and I6 are. sustained and held centered by radial connectors whose form is best shown in Figs. 1 and 3. Near the bottom of the sleeve l5 there are four stirrup members 13 and near the top of the same sleeve are four radial spacers I4. Opposite ends of these members l3 and I4 are connected to the sleeves l5 and i5 and to the outer shell 9 by means of bolts II which pass through tubular spacers l8 as clearly indicated in the drawings.

An annular fuel tank I9 is mounted in the interval between the outer sleeve l5 and the shell 9. It is spaced from the shell ii to afford a vertical air passage. It rests on the stirrup irons l3 and is removably retained by the radialmembers M. It has a fllling opening with cap 2| (see Figs. 1 and 3).

Besides rendering the fuel tank removable, this construction protects the fuel tank from overheating and applies usefully heat from the burner to stimulate airz circulation. The intervals betweenthe sleeves I5 and I6 and between the sleeve l5 and the inner wall of tank l9 develop a decided chimney eflect, promoting the circulation of air throughthe heater, and this active circulation causes the thermostat to respond more nearly to the actual temperature in the car.

The main burner is mounted in the lower or base section 6 and comprises an annular trough 22 supported by legs 23 and heat insulating spacers 24 on the lower head I. The annular trough in the burner contains a porous fibrous incombustible wick 25 which in practice is made of asbestos. It is held above the bottom of the trough by a zig-zag spacer 20. Extending from the outer margin of burner 22 at the top thereof is a foraminous baflie or screen 26 which extends outward and downward to the lower margin of the chimney 16, to which it is rigidly attached. The purpose of this screen is two-fold. It regulates the flow of air to the chimney outside the till i 2,215,767 burner and it is kept cool by the up-flowing air,

so that it. serves effectively as means to resist passage of heat from the burner downward to the thermostat, and to the jfloat chamber ,hereinafter described.

Concentric with and mounted within the burner 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 28. This cap is imperforate exin the annular main burner 25 and tangent thereto. It is of the incombustible wick type and is located adjacent to an ignition "opening formed in the ioraminous baifle 21 and intended to permit the transfer of flame from the pilot burner to the main burner. Opposite this opening and extending across and dividing the pilot flame is a flame divider or baiiie 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 flame. The'divider is carried by a sleeve which slips onto the upper margin of the pilot burner shell.

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

The upper end of the main chimney sleeve The openings whose form and arrangement are best shown in Fig. 3 are designed to give adequate circulation.

and at the same time to afford themaximum 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 t. The combustionair flows through the screen bafiles 26 and 33 to the combustion zone and thence upward through the chimney Hi. Other air, however, flows upward" through the annular. passages around the tank it and between the chimney lfiandthe sleeve [1%. This air is heated in greater or less degree and thus serves two useful purposes, 1. 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 the main burner 25 is the =float valve mechanism [indicated by the numeral 4| applied to its hous-' The float chamber 4| also supplies iuel through the connection 43 to themain 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 the thermostat 40. With this general explanation of the organization of the fuel control, reference will now be made to Fig. 4 in which the fuel control mechanism is shown in greater detail.

Fuel is led from tank is by pipe 65 to body 4| entering through filter cartridge t6 which is sealed in a chamber M by clamp 48.

chamber 41 the fuel rises through tube t9 whichi From contains the seat for needle valve 5|, and enters floatchar'nber 52. The needle valve is actuated by float 53, pivoted at 54 and counterweighted at 55. The effect is to maintain fuel in chem ber 52 at the level A-A..

Connection 42 leads from. the bottom of cham- I ber 52 to pilot burner 3t.

- Connection 43 communicates with chamber 58 in the lower portion of body 4|, and fuel flows irom chamber 52 to chamber 58 under the control of needle valve M which is actuated by lever 51 of the thermostat through rod 58. The shell or housing of the thermostat is the expansible element and is made of aluminum. The neutral element comprises two spring bows 59, 6| composed of an alloy sold under the trade name "Invar. This is an iron nickel alloy and has a negligible coeiiicient ofthermal expansion. the bows approach each other in response to falling temperature. A

Lever 51 is pivoted to bow 59 and bow 6i reacts against the lever through the adjustable thrust screw 52 which has a graduated milled head 63.

An index 84 indicates the adjustment and a spring detent (see Fig. 1) preserves the adjustment. The parts are so arranged that falling temperature tends to open the valve.

Since screw 6! acts on the lever 5i 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 i 63 merely changes the temperature atwhich the valve starts to open. It reaches full capacity with very slight lift, so that the control is sharp, approaching a simple on and of? action, rather than graduated opening and closing since such graduatlon as occurs is within a very small temperature'range.

A bathe til of heat insulating material protects the burner.

Thus a the thermostat from heat radiating directly irom a No novelty is here cla ed for the structure of the float valve per se 0 for the structure of the thermostat. The thermostat has the desirable characteristic for car service of being little effected by vibration. The double bow arrangement not limiting,'except to the extent expressed in the claims. What is claimed is:

1. In a heater for use in heating refrigerator- .cars, the combination of a ported base for enclosing controlling mechanism; a chimney carried by and mounted above said base and arranged to induce when heated, drafts of air which .enter the ports in thebase and flow thence upward through and around the chimney; an annular burner including a basin and a wick mounted within the lower portion of the chimney and spaced therefrom;'constant level liquid fuel feeding means for the burner; a thermostat mounted in said base in the path of air entering through the ports in the base and arranged to regulate the supply of fuel from said constant level means to said burner; and means serving to control the flame of said burner and to protect said thermostat from stray heat from said burner, said means comprising'a foraminous heat conducting annular partition extending upward from the inner margin of said burner a substantial distance within said chimney, and a foraminous heat conducting circulation past the thermostat and thence to the burner.

CHESTER A. RICHARDSON.-

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