Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
  • F23K5/00—Feeding or distributing other fuel to combustion apparatus
  • F23K5/02—Liquid fuel
  • F23K5/04—Feeding or distributing systems using pumps

Definitions

• Oil supply arrangement for a burner feed device for a burner feed device.
• the invention relates to an oil supply arrangement for a burner feed device having a pump which has two main connections, namely, an intake connection and an output connection which is connected to the burner feed device.
• Such oil supply arrangements are known, for example, from DE 38 00 300 Al or DE 38 14 530 Cl.
• the pump has to be of such a size that it is capable of generating the pressure required for the burner feed device, for example, a burner nozzle, and, on the other hand, the pump also has to be capable of drawing oil from a reservoir tank by itself.
• the pump has to be designed for a large volume, so that an intake of oil, for example, following interruptions to operation, can take place within a reasonable time.
• the pump therefore conveys an amount of oil that far exceeds the requirement of the burner feed device.
• the excess oil is returned to the reservoir tank again by way of corresponding valves downstream of the pump.
• the efficiency of the known oil supply arrangements is consequently relatively poor.
• the invention is therefore based on the problem of combining an improved efficiency of the oil supply arrangement with a high intake capacity.
• the pump is in the form of a gear pump, the gear assembly of which during one rotation forms displacement chambers that periodically increase and decrease in volume, at least one auxiliary connection being provided in the circulation direction between the main connections, the auxiliary connection being in fluid connection with the intermediate space between the components of the gear assembly and the main connection lying downstream in the circulation direction.
• the gear assembly of such a gear pump generally consists of a gear wheel, which is arranged eccentrically within an annular gear and meshes with this.
• the gear wheel rotates relative to the annular gear.
• Individual displacement chambers are created between the gear wheel and the annular gear. The volume of these chambers is smallest when a tooth of the gear wheel meshes with a gap in the annular gear.
• the volume of the displacement chambers is largest when two tooth tips of the gear wheel and the annular gear lie opposite one another.
• different pressure levels can be created during one rotation and the individual pressure steps can be used as required in order to save energy.
• With the assistance of the auxiliary connection of which there is at least one, it is possible to ensure that the pump need provide essentially only the capacity that is required to generate the pressure in a volume of oil that corresponds to the requirement of the burner feed device.
• auxiliary connection for the auxiliary connection to be arranged in the circulation direction between the output connection and the intake connection and to be connected to the output connection.
• the oil that is removed at the output connection is at a relatively high pressure.
• the oil fed in from the output connection by way of the auxiliary connection is especially preferable here for the oil fed in from the output connection by way of the auxiliary connection to have a driving effect on the gear assembly.
• the fed-in oil is relieved of pressure as it is fed into the intermediate space between the gear wheel and the annular gear, that is to say, the pressure of the oil drops, but since the oil is fed in between the output connection and the intake connection, that is, in a region where the displacement chambers increase again, the relief of pressure in the oil can be used to have an enlarging effect on the displacement chambers and thus contribute to a part of the driving power.
• a second auxiliary connection can be provided in the circulation direction between the intake connection and the output connection, and be connected to the intake connection.
• oil can be removed even at a low pressure and returned to the intake connection again. Since this amount of oil no longer needs to be brought to the pressure necessary for the burner feed device, the driving power, which is dependent both on the pressure increase and on the volume brought to the desired pressure, can be quite drastically reduced. Even when the oil at the second auxiliary connection cannot completely be removed without pressure, the pressure is not completely lost. The oil is then available with a correspondingly higher pressure at the intake connection.
• the second auxiliary connection supplies oil at a lower pressure and in a larger volume than the output connection.
• the intake volume generally exceeds the requirement of the burner feed device by a quarter. Basically, the entire amount of surplus oil can be removed at the second auxiliary connection at low pressure. Generally, however, a certain reserve will be allowed for the burner feed device.
• the auxiliary connection discharges into the gear assembly closely behind a position at which such an extreme value occurs.
• this has the advantage that the oil has experienced virtually no noticeable increase in pressure.
• this has the advantage that here the driving power of the oil under pressure can be utilized from the start and therefore practically completely.
• the main and auxiliary connections are separated from one another by at least one contact point between the components of the gear assembly. This means that no oil is able to flow back into the pump, which also has a positive effect on efficiency.
• the intake connection, the output connection and the auxiliary connections are prevented from being connected temporarily to one another.
• each displacement chamber is always in connection with at least one connection throughout a rotation.
• pressure peaks are consequently prevented from occurring.
• No oil volumes can be trapped between the gear wheel and the annular gear.
• the pump is of the gerotor type.
• both the annular gear and the gear wheel rotate in the housing, the axes of the gear wheel and the annular gear lying in a fixed plane.
• the pump housing can be constructed with fixed connections.
• the displacement chambers automatically connect with the respective connections during rotation of the gear wheel and the annular gear. There is no need for further control means.
• the pump can be manufactured simply and inexpensively. Additional sources of energy for operating control means are unnecessary.
• a valve especially a non-return valve, is arranged between the main connection and the auxiliary connection connected thereto.
• the non-return valve opens from the output connection to the auxiliary connection associated with the output connection, and from the second auxiliary connection to the intake connection. This prevents oil from escaping when the burner feed device has to be dismantled or removed for maintenance purposes.
• auxiliary connection or its connecting line to the main connection to have a flow resistance with a predetermined ratio to the flow resistance of the associated main connection. This allows the volume flow of the oil to be controlled, that is, it is possible to determined what amounts of oil reach the burner feed device or burner nozzle and what are returned. Since the requirement of the burner feed device and the necessary intake capacity of the pump are known, the mode of operation most favourable in energy terms can be preset by selection of the flow resistances.
• FIG. 1 shows a first embodiment and Fig. 2 shows a second embodiment.
• the pump 5 is in the form of a gear pump and has an annular gear 7 rotatably mounted in a housing 6; a gear wheel 8, which is eccentrically mounted with respect to the annular gear 7, meshes with the annular gear.
• the gear wheel 8 is rotatably driven in the direction of arrow 9.
• the gear wheel 8 has one fewer teeth than the annular gear.
• the gear wheel 8 consequently rotates somewhat more quickly than the annular gear.
• the ratio of the rotational speeds corresponds to the quotient of the teeth numbers.
• the annular gear 7 can be driven by a motor.
• the annular gear 7 and the gear wheel 8 together form a plurality of displacement chambers 10.
• the number of displacement chambers corresponds to the number of teeth on the annular gear 7.
• the axes of rotation of the annular gear 7 and the gear wheel 8 are in a plane fixed in the housing 6.
• the gear pump is therefore of the gerotor type.
• the intake connection 11 is located in a region in which the volume of the displacement chambers 10 increases and the output connection 13 is located in a region in which the volume of the displacement chambers 10 decreases.
• the increase in the volume of the displacement chambers 10 creates a suction effect, with the help of which the oil can be sucked by way of the line 12 from the tank T.
• the decrease in volume in the region of the output connection 13 creates the necessary pressure by which the oil in the burner feed device can be atomised or prepared in some other way for combustion.
• An electromagnetic valve 18 is additionally arranged between the pump 1 and the burner feed device 2.
• the auxiliary connection 20 is arranged at a position at which the volume of the displacement chambers 10 just starts to increase.
• a further non-return valve 21 which opens in the direction of the auxiliary connection 20.
• Oil under pressure can now be conveyed by way of the return line 19 from the output connection 13 to the auxiliary connection 20. There, it enters the displacement chambers 10 and is relieved of pressure.
• the amount of oil supplied to the auxiliary connection 20 has a driving effect on the gear assembly formed by the gear wheel 8 and the annular gear 7.
• the energy stored in the oil under pressure is therefore able to be used at least partially for driving the gear assembly, so that ultimately the drive capacity for the pump 5 can essentially be limited to providing the oil required by the burner feed device 2 with the necessary pressure.
• the oil feed device 1 operates as follows: When the gear assembly 7, 8 is rotated in the direction of arrow 9, it sucks oil by way of the line 12 from the tank T and in the pressure line 14 brings it to a pressure that is determined by the pressure regulator 16.
• the electromagnetic valve 18 is closed. When the electromagnetic valve 18 is opened, a pressure is created in the burner feed device 2, which has a pressure-controlled valve 4. If the valve 4 responds very rapidly, the electromagnetic valve 18 may optionally be omitted. Oil which is not used by the burner feed device 2 is returned by way of the return line 19 to the gear assembly 7, 8 and serves to drive the latter.
• the quantity of oil that is able to flow through the return line 19 is dependent on the construction of the auxiliary connection 20. This is selected to be such that, despite an oil return through the return line 19, sufficient oil is available for the burner feed device 2.
• the return line 19 also serves to prevent the burner feed device 2 from dripping. As is known, this phenomenon occurs when, with the electromagnetic valve 18 closed, the line between the electromagnetic valve 18 and the burner feed device 2 is heated, a situation which occurs, for example, on account of heat radiation from a combustion chamber during periods of rest.
• the non-return valve 21 in the return line 19 ensures that the pressure at the burner feed device 2 is higher than the pressure in the return line 19. This has its advantage, for example, during maintenance, when the burner feed device 2 is dismantled.
• the non-return valve 21 also prevents accidental escape of oil where the tank is in a higher position than the oil feed arrangement 1.
• the annular gear 7 and the gear wheel 8 are constructed so that at least three points of contact are created between the gear wheel 8 and the annular gear 7 as the gear assembly rotates, these points being arranged so that the two main connections, namely the intake connection 11 and the output connection 13, and the auxiliary connection 20 are always separated from one another. This can be achieved most simply when each displacement chamber 10 is completely closed.
• the intake connection 11, output connection 13 and auxiliary connection 20 are arranged in the housing 6 so that each displacement chamber 10 is always in connection with one of these connections 11, 13, 20. This avoids pressure peaks.
• Fig. 2 shows a further embodiment, in which the same parts are given identical reference numbers and similar parts are given dashed reference numbers.
• the oil feed device 1' has a second auxiliary connection 22, which is connected by way of an auxiliary line 23 to the intake connection 11.
• the output connection 13 is reduced in size.
• the output connection 13 from Fig. 1 has been divided into the output connection 13' and the second auxiliary connection 22.
• the second auxiliary connection 22 is located in a position at which the volume of the displacement chambers 10 just starts to decrease.
• the oil which is supplied through the second auxiliary connection 22 to the intake connection 11 is therefore at a relatively low pressure level.
• the second auxiliary connection allows a large part of the drawn- in oil to flow back again to the tank T or to the intake connection 11. Only a small part of the oil, sufficient to cover the requirement of the burner feed device 2, is brought to the higher pressure and discharged by way of the output connection 13 ' .
• the pump 5' thus has a large intake capacity, without the total amount of drawn-in oil having to be brought to the pressure required for operation of the burner feed device 2.
• the line 12 can therefore be relatively long even with a tank arranged at a low level. Oil which is available at the output connection 13' over and above the requirement of the burner feed device 2 can be conveyed by way of the return line 19 to the auxiliary connection 20 in order to be used there for operation of the pump.
• the amount of the oil flowing through the auxiliary connections 20, 22 is determined by the construction of these auxiliary connections, that is to say, by their throttling effect.
• the ratio of the amounts of oil between the output connection 13' and the auxiliary connection 20 is determined from the consumption of the burner feed device.
• the amount of oil flowing through the pressure regulator 16 can therefore be considerably reduced. In an extreme case, the device can even be constructed without the pressure regulator. Should a rate regulation be necessary, this can be effected by regulating the speed of the pump 5.
• the return line 19 can also be taken to the intake connection 11, omitting the auxiliary connection 20.
• the improvement in efficiency is then achieved exclusively in that surplus intake oil is no longer brought to a relatively high pressure but is immediately discharged by way of the second auxiliary connection 22.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Rotary Pumps (AREA)

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Citations (7)

Family Cites Families (1)

• 1992
  • 1992-08-21 DE DE19924227716 patent/DE4227716C2/de not_active Expired - Fee Related
• 1993
  • 1993-08-13 WO PCT/DK1993/000262 patent/WO1994004874A1/en active Application Filing

Patent Citations (7)

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