COMBINED OIL DEAERATOR AND OIL PUMP

Technical field of the invention

The present invention relates to a combined oil deaerator and oil pump in an oil heating installation, whereby the oil deaerator comprises at least one float chamber with at least one float, the float chamber is provided with a float valve which communicates with the outside of the float chamber, the float being intended to cooperate with the float valve, and the oil pump comprises at least a first drive set, an inlet which communicates with an oil tank, and an outlet which communicates with an oil burner.

State of the art An oil deaerator already known from WO03061807 forms part of an oil heating installation which also comprises a tank, an oil pump and a burner. In that installation the oil deaerator and the oil pump are separate units. In addition to the fact that two separate units each require their own space, it is also necessary for the units to be connected together by hoses and connections, resulting always in potential risk of leakage occurring in those units.

Objects and features of the invention A primary object of the present invention is to provide a combined oil deaerator and oil pump in order to eliminate the hoses and connections between the previous oil deaerator and oil pump configured as separate units. This also results in reduction of the risk of leakage. Another object of the present invention is to unite the oil chambers of the two units, resulting in a compact version which may be accommodated under the oil burner cover.

A further object of the present invention is to use components which are as few in number, compact and easy to fit as possible.

At least the primary object of the present invention is achieved by a combined oil deaerator and oil pump having the features indicated in the independent claim 1 below.

Preferred embodiments of the invention are defined in the dependent claims.

Brief description of the drawings Embodiments of the invention are described below with reference to the attached drawings, in which: Fig. 1 depicts a section through a combined oil deaerator and oil pump according to the present invention;

Fig. 2 shows schematically how the combined oil deaerator and oil pump according to the present invention is disposed relative to the other components in an oil heating installation; Fig. 3 depicts a section through an alternative embodiment of a combined oil deaerator and oil pump; Fig. 4 shows schematically how the combined oil deaerator and oil pump according to the present invention is disposed relative to the other components in an oil heating installation;

Fig. 5 depicts a section through a further alternative embodiment of a combination of an oil deaerator, an oil pump and in addition an oil filter;

Fig. 6 shows schematically how the combined oil deaerator, oil pump and oil filter according to the present invention is disposed relative to the other components of an oil heating installation;

Fig. 7 depicts a section through yet another alternative embodiment of a combined oil deaerator and oil pump which is a simplification of the embodiment depicted in Fig. 1; and Fig. 8 shows schematically how the combined oil deaerator and oil pump according to the present invention is disposed relative to the other components in an oil heating installation.

Detailed description of preferred embodiments of the invention

The combined oil deaerator and oil pump according to the present invention depicted in Fig. 1 comprises an input shaft 1 driven by a power source (not depicted) which usually takes the form of an electric motor. The shaft 1 is supported for

rotation in a pump housing 2 which accommodates a drive set 5 (pump gearwheels) . The pump housing 2 has an inlet 27 connected to one end of a suction line 26 which has its other end connected to an oil tank 34 from which oil is drawn. A check valve 20 is disposed between the inlet 27 and the drive set 5.

The pump housing 2 also has an outlet 19 and a first duct 28 which extends between the drive set 5 and the outlet 19. The pump housing 2 is assembled to a float housing 29, thereby forming a first float chamber 10 which is common to the pump housing 2 and the float housing 29. A first float 11 and a first float valve 12 with which the first float 11 cooperates are disposed in the first float chamber 10. The first float valve 12 is disposed in an upper wall of the float housing 29 and connects the first float chamber 10 to a second float chamber 30 in which a second float 13 is disposed. A second float valve 14 and a venting hole 21 situated close to it in an upper wall of the second float chamber 30. A first overflow valve 18 is disposed between the first duct 28 and a second duct 16 which leads into the first float chamber 10.

A third duct 15 in the form of a pipe which leads at the top into the second float chamber 30 is disposed in the first float chamber 10. It should be noted that despite the impression which may be given by Fig. 1 the duct/pipe 15 does not constitute a dividing wall in the first float chamber 10. The third duct 15 is provided, in the region of its lower end, with a membrane 8 made of elastic material and with a compression spring 9 acting upon the membrane 8. A membrane chamber 31 is defined on the side of the membrane 8 where the compression spring 9 is situated.

The combined oil deaerator and oil pump comprises in addition a fourth duct 17 extending between the membrane 8 and the inlet side of the drive set 5. A regulating valve in the form of a second overflow valve 7 is disposed between the first float chamber 10 and the fourth duct 17 and opens when a certain pressure occurs in the first float chamber 10. The free end of the fourth duct 17 abuts against the membrane 8

when the latter is in a position of rest. The membrane 8 and the second overflow valve 7 together constitute a regulating means 7, 8.

The oil heating installation depicted in Fig. 2 obviously comprises a combined oil deaerator and oil pump forming a unit which has been given the reference numeral 25. Oil is supplied to the unit 25 via the suction line 26 and leaves the unit 25 via an outlet duct 23 which leads to an oil nozzle 24 of an oil burner 22. The combined oil deaerator and oil pump, i.e. the unit 25, and the other components of the oil heating installation function as follows. When the oil burner 22 starts, the shaft 1 and the drive set 5 (pump gearwheels) of the oil pump rotate. Oil is thus drawn from the oil tank 34 through the suction line 26, in through the inlet 27, in through the check valve 20 and into the drive set 5. From there the oil is pushed into the first duct 28 from which it proceeds through the outlet 19 and an outlet line 23 and out through the oil nozzle 24. The oil which is not consumed passes the first overflow valve 18 (which regulates the oil pressure to the oil nozzle 24) and proceeds via the second duct 16 into the first float chamber 10.

When oil from the second duct 16 begins to fill the first float chamber 10, the oil level rises and the first float 11 rises and closes the first float valve 12. The pressure then rises in the first float chamber 10, causing the membrane 8 to press against the compression spring 9, which gives way and thereby allows oil to pass through the fourth duct 17 into the duct 27 and proceed back to the drive set 5. The oil will thus circulate through the drive set 5 and the first float chamber 10 a number of times and only the oil which is consumed will be drawn into the oil pump from the oil tank 34. The membrane chamber 31 of the membrane 8 communicates with the atmosphere via the third duct 15, the second float chamber 30, the second float valve 14 and the venting hole 21. If for any reason the first float valve 12 does not close, the oil will rise in the second float chamber 30, causing the second float 13 to rise and close the second float valve 14. In this situation, communication between the

membrane chamber 31 and the atmosphere ceases and the membrane 8 will not function. To prevent the occurrence of harmful pressure in the float chambers 10, 30, the second overflow valve 7 opens, allowing oil to pass through it instead of via the membrane 8. The purpose of the check valve 20 is to prevent oil running back to the tank 34 when the oil burner is not in operation.

Figs. 3 and 4 depict an alternative embodiment of a combined oil deaerator and oil pump, Fig. 4 being identical with Fig. 2, i.e. it shows how the combined oil deaerator and oil pump is disposed relative to the other components of an oil heating installation, and the combined oil deaerator and oil pump in Fig. 4 has been given the reference numeral 25.

A known problem of conventional oil deaerators and oil pumps is that the oil and air coming from the tank have first to go through the oil pump, which means that some of the air will pass through the oil burner and the oil nozzle. As many oil pumps/oil burners are sensitive to air, this is a problem which is solved in this version by a further separate drive set which draws air-free oil from the bottom of the first float chamber 10 in the oil deaerator. Figs. 3 and 4 depict a combined oil deaerator and oil pump in which the oil pump is provided with two drive sets.

As the combined oil deaerator and oil pump depicted in Fig. 3 largely corresponds to the combined oil deaerator and oil pump in Fig. 1, the description above concerning Fig. 1 should mainly be referred to as regards the construction of the oil deaerator and the oil pump according to Fig. 3. Corresponding parts have been given the same reference numerals as in Fig. 1. The following constructional differences should nevertheless be noted. The first drive set 5 is not connected to the outlet 19, but a fifth duct 6 connects the outlet side of the first drive set 5 to the first float chamber 10. In addition to the first drive set 5, there is a further second drive set 3 mounted on the shaft 1. The second drive set 3 has its inlet side connected to the bottom of the first float chamber 10 via a sixth duct 4. The outlet side of the second duct 3 is connected to the outlet 19 by a

first duct 28 to which the first overflow valve 18 is connected.

The embodiment depicted in Figs. 3 and 4 functions as follows. When the oil burner 22 starts, the shaft 1 and the first drive set 5 and the second drive set 3 (pump gearwheels) rotate. Oil is thus drawn from the oil tank 34 through the suction line 26 into the inlet 27, through the check valve 20 and into the first drive set 5. From there the oil is pushed into the fifth duct 6 which leads into the first float chamber 10, which will fill with oil until the first float valve 12 closes, causing the pressure to rise and the membrane 8 to open so that oil enters the fifth duct 17 and proceeds back into the first drive set 5. In this case the first drive set 5 serves merely as a transfer pump maintaining a uniform oil level in the first float chamber 10. The second float 13 and second overflow valve 7 have the same functions as in the version according to Fig. 1.

What is new in the version according to Fig. 3 is that there is a further drive set, i.e. a second drive set 3, the sole purpose of which is to draw air-free oil from the bottom of the first float chamber 10 and push it out to the nozzle 24. The second drive set 3 functions in such a way that at the same time as the burner 22 starts, the drive set 3 begins to draw oil from the bottom of the first float chamber 10, through the sixth duct 4 and into the second drive set 3.

From there the oil is pushed through the first duct 28 and out through the first connection 19 to the oil nozzle 24 via the duct 23. The oil which is not consumed by the nozzle 24 passes the first overflow valve 18 (which regulates the oil pressure to the nozzle 24) and proceeds via the second duct 16 into the first float chamber 10.

The oil which is consumed is drawn from the first float chamber 10, causing the pressure/level to drop somewhat in the first float chamber 10. The membrane 8 detects the pressure difference and retards the flow from the first float chamber 10 via the fourth duct 17, thereby causing the first drive set 5 to draw more oil from the tank 34 until an equilibrium is reached between the oil being burnt and that being drawn from the tank 34.

Figs. 5 and 6 depict a further alternative embodiment of a combination of an oil pump, an oil deaerator and in addition an oil filter. The purpose of this version is to render the unit still more compact and thereby eliminate external components outside the oil burner. This embodiment entails a combination of the very latest technology in each field and special solutions if the resulting combination is to be small enough and function well.

The functions of the oil deaerator and the oil pump are the same as in the embodiment according to Fig. 3, i.e. with two separate drive sets, so only the filter function will now be described.

R filter housing 61 with a filter chamber 62 is connected to the combined oil deaerator and oil pump. When the oil burner 22 starts, oil is drawn from the oil tank 34 via the suction line 25 into the second connection 60 on the filter housing 61 and proceeds into the filter chamber

62. The oil is filtered there by, for example, a paper filter

63, passes into the inlet 27 and via the check valve 20 into the first drive set 5, proceeds into the first float chamber

10, and so on. Thereafter the function is the same as in the embodiment according to Fig. 3.

Figs. 7 and 8 illustrate yet another alternative embodiment of a combined oil deaerator and oil pump with one drive set. The function of this version is almost identical with the embodiment according to Fig. 1, but the membrane 8 and associated ancillary eguipment are omitted. The regulating means thus takes the form of the second overflow valve 7, which assumes the function of the membrane 8. The function described below is confined to the difference between the embodiment according to Fig. 1 and the embodiment according to Fig. 7. When the oil burner 22 starts, the shaft 1 and the drive set 5 (pump gearwheels) rotate. Oil is thus drawn from the oil tank 34 through the suction line 26 into the inlet 27, in through the check valve 20 and into the drive set 5. From there the oil is pushed into the first duct 28, from which it proceeds through the outlet 19, the nozzle line 23 and out through the nozzle 24. The oil which is not consumed passes the first overflow valve

18, which regulates the oil pressure to the nozzle 24, and proceeds through the duct 16 into the first float chamber 10 formed by the pump housing 2 and the float housing 29.

When the oil from the second duct 16 begins to fill the first float chamber 10, the oil level rises and the first float 11 rises and closes the first float valve 12. The pressure then rises in the first float chamber 10, causing the second overflow valve 7 to begin to open and allow oil to pass through the fourth duct 17 into the inlet 27 and back into the first drive set 5. The oil will thus circulate through the first drive set 5 and the first float chamber 10 a number of times and only the oil which is consumed will be drawn from the oil tank 34 and into the pump.

If the first float 11 does not close the first float valve 12, oil will flow up through the first float valve 12 to the second float chamber 30, causing the second float 13 to close the second float valve 14.

The purpose of the check valve 20 is to prevent oil from running back to the tank 34 when the oil burner is off.

Conceivable modifications of -the invention

In the embodiments described above, the regulating means of the first float chamber 10 takes the form either of a second overflow valve 7 alone or a membrane 8 in combination with a second overflow valve 7. It is nevertheless possible within the scope of the present invention to also conceive of the regulating means taking the form of the membrane 8 alone, in which case the second overflow valve 7 is omitted. Instead of using a regulating means in the form of a second overflow valve 7, it is also possible within the scope of the invention to conceive of using a regulating means in the form of a level valve, i.e. a valve which opens when the oil reaches a certain level in the first float chamber. Such a level valve is preferably controlled by a lever arm extending between the first float and the level valve. The level valve may also be combined with a membrane, in which case the regulating means takes the form of the membrane in combination with the level valve .

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In all the embodiments of the invention described above, the oil deaerator is provided with two float chambers each accommodating one float. Within the scope of the present invention, however, it is possible to conceive of the oil deaerator comprising only one float chamber in which at least one float is disposed. Such an embodiment of an oil deaerator is described in SE-B-341 231. The oil deaerator having only one float chamber makes no difference to what is stated above concerning the various types of regulating means described above. In cases where an oil deaerator with only one float chamber is provided with a membrane, the duct belonging to the membrane leads into the open air outside the oil deaerator.

In the embodiment according to Fig. 5, i.e. a combination of an oil pump, an oil deaerator and an oil filter, the oil pump is provided with two separate drive sets 3 and 5. Within the scope of the present invention, however, it is possible to conceive of a combination of an oil pump, an oil deaerator and an oil filter where the oil pump is only provided with one drive set 5, i.e. corresponding to the case of the oil pump according to Fig. 1.

Although the present invention primarily relates to a combined oil deaerator and oil pump, it should be noted that the principle depicted in Fig. 7 of an oil deaerator with no membrane, i.e. with the second overflow valve 7 serving as regulating means and regulating the pressure in the oil deaerator, may also be applied in the case of a separate oil deaerator, i.e. an oil deaerator constituting a separate unit. Such an oil deaerator in the form of a separate unit may also have a level valve as regulating means. Such an oil deaerator in the form of a separate unit with no membrane may be used together with an oil pump in the form of a separate unit which may have only one drive set or two separate drive sets.

In the above description and in the claims set out below, the expression "drive set" means the gearwheel arrangement which constitutes the oil pump's raising means. These gearwheel arrangements may be constructed in various different ways. The expression "drive set" also covers these various types of gearwheel arrangement.