Patent GB-822288-A (GB)
Title: Improvements to fluid heating appliances
Inventor: LEVIANT ISRAEL
IPC: F23D11/08
Filed: 1955-09-14
Abstract: 822,288. Liquid fuel burners; lighting burners. TECHNI-COM S. A. Sept. 14, 1955, No. 26274/55. Classes 75(1) and 75(3) An apparatus for heating liquids by means of a liquid fuel burner, comprises a liquid fuel raising device consisting of a tube 4 rotated by an electric motor 3 and a fixed tube 22 surrounding tube 4 at the base of which tube 22 there is formed a fuel admission chamber communicating with the interior of the tube 22 through central and peripheral apertures 23a, 23b, the tube 4 carrying at its upper end a cup 5 which rotates therewith while at its lower end there is provided an extension tube 21 which enters the fuel admission chamber through the central aperture 23a so that the tube 4 does not rotate directly in the chamber, an electric ignition resistance 7, a double level fuel indicator system 30, 33, a feed device for maintaining the fuel level constant, an automatic contactor device for controlling the motor 3 and a fan 18, and a second automatic contactor device controlling the ignition resistance 7. In the liquid fuel raising system shown in Figs. 1 and 2, the fixed tube 22 is so mounted that its top part remains above the fuel level in the reservoir 2 and its bottom part is at a predetermined distance above the bottom of a tank 2a. When the shaft 4 is rotated the top level of the fuel funnel in the tube 22, caused by viscous drag; cannot exceed a certain height since the pressure produced causes the discharge of the fuel through the apertures 23b in the direction of arrows while the fuel 'enters the tube 22 through the central aperture 23a. The cross-section of the apertures 23a, 23b can be chosen to limit the funnel level to a predetermined height. In an alternative arrangement, Fig. 3 (not shown). an annular member resting by means of fins on a central apertured base member replaces the apertured diaphragm shown in Fig. 2. In a further alternative arrangement, Fig. 4 (not shown), the tube 22 is closed at its lower end by a disc of wire cloth, perforated metal or filtering material. The reservoir 2 is filled with fuel from a bowl 27 through a tube 29 leading to a bowl 55, Figs. 5 and 6, and then overflows into the tube 22. The air in the reservoir 2 is expelled through a siphon 54 the free end of which is immersed in the fuel contained in the bowl 55. The level of fuel in the tube 22. is established at a height above the level of A-B in the reservoir 2 by reason of the counter pressure created by the length of the siphon 54 immersed in the bowl 55. The height of 'the fuel level in the tube 22 is adjusted by a device shown in Fig. 6 comprising a first tube 37 carried by a threaded ring 38, attached to the top of the reservoir 2, and fixed at its top edge to a washer 40 on which washer 40 is welded the top edge of a second tube 41 closed at its base by a stopper 42, The stopper 42 is provided with a hole 42a and the passage 42b. A third tube 43 fixed in the washer 40 and welded at its bottom edge to the stopper 42 serves as a bearing surface for a nut 44 through which nut 44 passes a threaded rod 45. The nut 44 is held in position by a stop 46 attached to a casing 1 and is keyed to prevent the rod 45 turning therewith. A tube 47 is fixed at the bottom of the rod 45. Another tube 48 fixed in a central hole in the stopper 42 communicates with the passage 42b and rises inside the tube 47. An aperture 49 is provided in the top of tube 41. The nut 44 can be knurled on its periphery and be of small diameter so as to be accessible from the interior of the casing 1 when the reservoir 2 is removed or it can be of larger diameter - and pass through a slot in the casing wall so as to be accessible from the outside of the casing 1, or, as shown in Fig. 6. can be fixed to a toothed crown 50 meshing with the pinion 51 rotated by a knob 53. The annular space between tubes 43, 47 is filled with fuel at the same level as the tube 22 while the level A-B is established in the annular space between tubes 47, 48. The central tube 48 and the annular space formed between the tubes 41, 43 do not contain fuel. When the appliance is used the level A-B + h in the tube 22 drops and it follows that fuel rises from the bowl 55 into the free end of the siphon 54 and its level is finally established at h<SP>1</SP> when the level A<SP>1</SP>-B<SP>1</SP> is established in the tube 22. When the fuel level in the tube 22 reaches A<SP>1</SP>-B<SP>1</SP> this level is established in the space formed between tubes 43, 47 thus uncovering the bottom edge 47a of the tube 47 and permitting air to enter the reservoir 2 through the space between the tubes 47, 48, the central tube 48, passage 42b, the space between tubes 41, 43, hole 49 and finally the space between tubes 37, 41. The air pressure in the reservoir 2 increases slightly to cause a slight reduction in the level A-B and a rise in the level A<SP>1</SP>-B<SP>1</SP> so that the edge 47a is once more covered to stop the air admission until a sufficient amount of fuel is withdrawn from the tube 22 to lower the fuel level to A<SP>1</SP>-B<SP>1</SP> and again uncover the edge 47a. The level A<SP>1</SP>-B<SP>1</SP> can be varied by raising or lowering the tube 47 by the nut 44 and rod 45. The fuel level in the reservoir 2 is indicated in the transparent tube 30 connected to the top and bottom of the reservoir 2 by pipes 31, 32 and the level of the fuel in the tube 22 is indicated in a second tube 33, Fig. 5, communicating at its top with ambient air and at its bottom to the tank 2a through a pipe 34. The rotating burner cup 5, Fig. 7, comprises a lower conical part 5a and an inverted conical rim 5b. The fuel is retained in the rim of the cup 5 and is then discharged at a speed corresponding to the peripheral speed of the maximum internal diameter of the cup to promote atomization. The internal surface of the cup may be porvided with grooves or may be roughened. The fuel is projected by the cup 5 into a funnel 6 provided with vents 6a having rims 6b to prevent droplets of unvaporized fuel from passing therethrough. The fuel trickles down the inner surface of the funnel 6 returns to the reservoir 2 through a hollow 20a passage 20b and the tube 20c A jacket 56, which protects the electric ignition resistance 7 from eddies of air forced by the fan 18 through vents 6a, is provided in the neck 6c of the funnel 6 so as to allow a small space 6d. The jacket 56 supports a series of wires 57 which extend above and terminate near the cup 5 and which catch droplets of fu@ so as to direct the fuel droplets towards the resistance 7 to promote ignition thereof. The resistance 7 is operated by a known device comprising the casing 58 closed at its bottom part by a flexible device carrying a contact 60 which is brought into contact with fixed contact 62 carried by a leaf spring 61. When the air pressure in the combustion chamber before ignition is equal to that generated by the fan 18 the contacts'60, 62 are closed to energize resistance 7 but when the pressure rises in the combustion chamber as a result of the rising temperature such rise in pressure is transmitted through tubes 63a and 63 to the diaphragm 59 and the contacts 60, 62 are opened. The pressure at which the contacts 60, 62 open can be regulated by a nut 71. The device is detachably supported on a wall 65 by tube 63 and electric connections 66, 67 engaging sockets 64, 68 and 69. The motor 3 is controlled by a device placed in the admission pipe 73, 13 of the flued to be heated. The device comprises contacts 78, 79 arranged in a circuit to the motor 3 and operated to the closed position by a piston of plastic material suitably guided in the pipe 73. When the fluid flows in the pipe 73 the piston 74 tilts the rod 77 carried by a flexible thin or grooved walled metal tube to close the contacts 78, 79. If the vapour pressure of the heated fluid exceeds the fluid input pressure the rod 77 is tilted to open the contacts 78, 79.