US2616022A - Instantaneous heating of a fluid circulating in a tube - Google Patents

Description

Oct. 28, 1952 H. ARNAUD 2,616,022

INSTANTANEOUS, HEATING OF A FLUID CIRCULATING IN A TUBE} Filed Jan. 4, 1949 s Sheets-Sheet 1 INVENTOR: HENRI ARNAUD ATTORNEY Oct. 28, 1952 2,616,022

INSTANTANEOUS HEATING OF A FLUID CIRCULATING IN A TUBE Filed Jan. 4, 1949 H. .ARNA UD 3 Shuts-Sheet 2 IN VENTOR: HENRI HRNAUD ATTORNEY H. ARNAUD Oct. 28, 1952 INSTANTANEOUS HEATING OF A FLUID CIRCULATING IN A TUBE 3 Sheets-Sheet 3 Filed Jan. 4, 1949 I N VENTOR; HENRI ARNA up HTT'ORNEY Patented Oct. 28, 1952 OFFICE" INSTANTANEOUS, HEATING OF A FLUID CIRCULATING IN A TUBE Henri Arnaud, Paris, France ApplicationJanuary 4, 1949, Serial No. 69,201 In France January 6, 1948 2 Claims.

1 Fuel oil burners require, for giving a satisfactory efficiency and an even working, a perfect atomizing of the fuel oil condition which can be obtained only with fuel oils having a low viscosity. On the other hand it is useful for a few reasons, to use heavier fuel oils which are cheaper.

The viscosity of fuel oils decreasing when the temperature increases, it is already known to previously heat them in order to bring the viscosity down to an appropriate value, the heating tem-.

the tube connected with the. nozzle as an electric heating resistance.

According to an embodiment of the invention, said portion of the tube forms the secondary coil ofv a transformer, the primary coil of which is fed by the power of the mains.

According to another embodiment, the linear expansion of the tube feeding and heating said fuel oil is used for actuating a switch ensuring the switching off of the circuit feeding the transformer, With that object the tube comprises, at an appropriate point, 2, lug or stop arranged in front and at a certain distance of the member controlling the switch, in such a way that due to the expansion of the tube, the lug or stop may come into contact with said member, and by acting upon it actuate the switch.

Means are provided for adjusting the distance, at rest, between the lug and the member controlling the switch.

The lug is for instance provided with a cam which is rotatably movable by hand.

Finally the heating device is arranged as a set or block comprising the transformer, the part of the tube forming the heating element, the switch of the feeding circuit and the control device of that switch, these different parts being secured on a plate and protected through an easily detachable casing.

The invention is not relative only to the heating of fuel oil in fuel oil burner devices but its scopeis extended to the instantaneous heating of any fluid or liquid circulating in a metallic tube having a small section, the portion of the tube to be. heated forming, according to theinvention, a heating resistance and more particularly forming the secondary coil of a transformer.

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The foregoing objects and advantages will be made fully apparent from the following descript1on reference being had to the accompanying drawings, and it will be understood that the devices shown are only given by way of example the actual scope of the invention being deter: miFned by the appended claims.

1g. is a diagrammatic view 0 a I ofFcongentional fuel oil burner. f eqmpment 1g. is a diagrammatic view of of fuel oil burner according to'the iriie t i Figs. 3 to 5 show different embodiments of the invention. I

Fig. 6 is a diagrammatic trol of the switch.

Fig. 7 is a perspective diagrammatic view showing the shape of the tub to be heated e in which flows the fluid Fig. 8 shows, on a larger scale, de '0 adjusting of the distance betweeri the lifg i 1 1: switch control and the rod of said switch.

g g. iliois a side view of said device. 7

1g. is a front view of the heatin acgaordilnlg to the present invention. g apparatus 1g. is a cross-section "of Fig. 1

lmIe1 XIg-XI of said figure. along the or er to well understand the adva the device described hereafter, the equip izii 8; a burner with automatic atomizing will be first recalled. This equipment comprises, as shown in Flg, 1, a motor driving a fuel pump a which through a pressurevalve b, delivers at a constant pressure, through a tube 0, the liquid fuel toa member d called jet which atomizes said fuel the surplus fuel being returned, through tube to the inlet c1 of the pump. I v

In the embodiment shown in Fig. 2, the tube 0 feeding the fuel oil from valve b to jet (1 is madeof a metallic tube having a small section coiled at 6 around the core of a voltage transformer f of the conventional type, and thus forms the secondary coil of said transformer. A copper wire 9 having a very large section connects points I and: sfuch a manner that the secondary and eaeormacirc' resistance. uit I g, 2, 01, I having a low The length of the tube, the number of turns of the secondary circuit will evidently be a function of the power to be dissipated in that tube for ensurmg the required heating. 7

view showing the con- As the resistance of the secondary circuit is very low and the power evolved as heat is directly proportlonal to R1 consequently the intensityofthe current circulating in said circuit is con siderable. The tube will be heated through-Joules effect as soon as the primary cell of the transformer is energized. The fuel will thus progressively be heated from point i up to point 2. The exchange of heat between the fuel oil circulating in the tube and the wall of said tube heated by J oules effect will be made easier due to the relatively high speed of said fuel oil.

The very low calorific inertia of the portion of tube 01 and of the small quantity of fuel oil therein contained is such that the above described heater is a heater giving an almost instantaneous heating.

For instance, in the case of a burner which should deliver 30 litres of light fuel per hour, heated from 10 C. to 60 C., a simple computation shows that the power evolved as heat is of about 875 watts (the total efficiency being 60% according to an estimate).

The heating circuit may be in practice made of a 4/6 copper tube (that is having an inner diameter of 4 millimetres and an outer diameter of 6 millimetres) having a length of 1.75 metres and comprising two turns, the number of turns of the primary circuit of the transformer fed with alternating current 220 volts 50 cycles being 300.

The voltage at the secondary is about 1.6 volts which is extremely low and gives full protection from the point of view of safety.

The regulation of the temperature of the fuel oil at point 2 may be obtained in different ways either using a transformer having a plurality of connection contacts h with a moving handle 2', Fig. 3, and varying the voltage at the primary winding, or modifying the length of the heating portion 01 of tube a (Fig. 4), through a moving jaw 1c, provided at the end of wire g and which may slide on the portion of tube c connected with valve b.

The instantaneousness of the heating of the described device has a great advantage in so called make-and-break burners which stop and start when operated by a self control (through temperature, pressure, etc. It is indeed possible to connect in parallel the motor and the primary coil of the transformer in order to obtain at the same time the atomizing and the heating of the fuel.

Although the inertia of the heating device is extremely low, it is possible to practically cancel it, when starting, by means of a contactor with an adjustable retarding device which sets the motor to work a few seconds after the primary coil of the transformer is energized.

The closing of the secondary circuit for heating, instead of being made through wire 9, might be obtained through the tube for the circulation of the fuel oil which, with that object, is for instance curved as shown at 02 in Fig. 5, the curved portion being welded at the end of tube connected with jet d. Any other arrangement could of course be provided.

According to another embodiment, a portion of tube 0 is rectilinear as shown at 0:; (Figs. 6 and 7) and near one of the ends of this rectilinear portion a collar or double clamp l is provided which rigidly binds the two branches of tube 0 and thus closes the secondary circuit, in the same way as wire 9 (Figs. 2 and i) or as the welding designed in Fig. 5.

Near the other end of the rectilinear portion 03' a lug or stop 8 rigidly locked with the tube is provided, said lug being arranged in front of a sliding rod or lug 9 which is the member operating the switch provided for switching off the p-ri mary coil of the transformer.

The collar 1 and the casing 10 of the switch are mounted on a same support, which defines a constant spacing between these two parts in spite of the expansion of the tube.

In that way, it is easy to understand that when the portion 03 of the tube increases in length. due to the expansion resulting from the heating of the tube, the lug 8 may come into contact with lug 9 and push it in order to actuate switch 10 and thus switch off the feeding circuit of the transformer, avoiding any excessive increase of temperature. The circuit will be closed again when the lug 9 can, under the action of a return spring, take back its initial position, that is when the tube is cooled enough for allowing lug 8 to be brought back to its initial position.

The contactor I0 will be of the micro contactbreaker type (which is commercially manufactured) and in which a displacement of a few hundredths of a millimetre of its operating lug 9 produces a sharp breakof current.

In order to'allow an accurate trigger action of the micro contact-breaker and to make easier the adjusting of the temperature of the tube above which the current should be switched off, a device enabling to accurately adjust the distance between lug 3 and the end of lug 9, is designed between both parts.

' With that object, the lug 8 (which is made of i a collar in two portions 811, 8b) instead of being located immediately in front of the lug 9 of the switch, is laterally shifted with respect to that lug and bears a small cam l I (Figs. 8 and 9) ar ranged in front of said lug. That cam may be angularly moved by operating a thumb screw I2 which protrudes over portion 8a.. According to the angular position of the cam, the distance between said cam and lug 9 is increased or decreased. A spring [3 is designed for braking the rotation of screw I2 and consequently of the cam in order to ensure a perfect stability of the angular position of said cam.

That cam I! may be made simply with a disc in an offset arrangement with respect to its center of rotation, and the latter may be a screw [4 rigidly locked with screw l2 and screwed in the portion 8a of lug 8. :1

According to a modification of the above embodiment, the above described members are ar- Y ranged as shown in Figs. 10 and 11, in which said members are mounted on a plate l5.

The whole set of the transformer, laminated core l6 and coil IT is arranged approximately at the center of plate l5. The bobbin l1 comprises,

in the conventional way, several coils, and a terminal plate It enables to insert in the circuit a variable number of these coils in order to adjust at will the intensity of the current and consequently the production of heat through Joules effect. One of the wires feeding the current is connected to the terminal I9 which is connected through the wire 20 with one of the contacts of the micro contact-breaker It], the other contact being connected through the wire 2| with the terminal 22 connected with the inlet of bobbin II.

By connecting the other wire of the feeding to 23f, it is pos-;

any one of terminals 23a, 23b sible to modify at will the intensity of the current, the maximum intensity being obtained by connecting that second wire to terminal 23a.

tube which forms the secondary coil is arranged as shown in Figs. and 11.

The jaw or double strap 7 and the stop 3a, 8b are secured to a plate 24 ensuring the setting of these members with a defined spacing. This plate 24 is secured to plate 15.

A cover 25 covers the whole plate i5 and ensures an emcient protection for the members secured to said plate. Of course holes are designed in that cover for the passage of the connections with the ends 5 and 6 or" tube 0.

It is convenient to vertically arrange plate 15, as it is shown in the drawing. That plate is for instance secured to a wall or to a vertical support, and with that object, holes 26 are designed at its upper end, said holes enabling to secure it with screws 21.

Holes 28 are designed at the upper end and at the lower end of plate l5, in order to enable the circulation of air inside of the cover. venient to cut and shape these holes in order to obtain a rounded portion as shown at 29, in such a way that these holes may be conveniently used as handles for the handling of the apparatus.

It is to be noted that the present heater may be used to instantaneously heat any other fluid than fuel oil and may thus be used in other scientific or commercial equipments.

It is also to be understood that the above shown and described embodiments have been stated only as examples and could be modified, particularly in substituting equivalent technical means without departing from the scope of the subjoined claims.

What I claim is:

1. An electrical liquid heating apparatus comprising in combination an electric transformer provided with means for energizing its primary winding, a metallic tube comprising a coiled portion forming the secondary winding of said trans- It is conare secured to establish a secondary circuit consisting of the coiled portion, connecting portion, rectilinear portion and electrically connecting means, and switch means actuated by said lug for switching oif the current in the primary winding of said transformer for a predetermined heat expansion .of said rectilinear portion.

2. An electrical liquid heating apparatus comprising in combination an electric transformer provided with means for energizing its primary winding, a metallic tube comprising a coiled portion forming the secondary winding of said transformer and a rectilinear portion, a stationary support secured to said rectilinear portion, a lug provided with an aperture therethrough secured to said rectilinear portion at a distance from said stationary support, means for electrically connecting two points of said tube respectively before said coiled portion and after the part of said rectilinear portion to which said support and lug are secured, a pin mounted for rotation in said aperture of said lug and provided at one end with a cam and at the other end with a thumb piece, a spring between said thumb piece and said lug for braking the rotation of said pin and ensurin a stable position of said cam, and an electric switch in series with the primary winding of said transformer supported by said stationary support and arranged and adapted to be actuated by said cam for a predetermined expansion of said rectilinear portion.

HENRI ARNAUD.

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

UNITED STATES PATENTS Number Name Date 1,122,892 Farrand Dec. 29, 1914 1,402,021 Snelling Jan. 3, 1922 1,474,777 Jarkovsky Nov. 20, 1923 1,513,087 Buhl et a1 Oct. 28, 1924 1,951,649 Delano Mar. 20, 1934 2,104,940 Woolery Jan. 11, 1938 FOREIGN PATENTS Number Country Date 461,568 Germany May 31, 1928

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