Screw pump with at least two parts

Abstract

A screw spindle pump constituted by at least two parts is disclosed. The first part includes a housing and at least one spindle system disposed in the housing and capable of being driven in a rotational manner. Furthermore, a pressure region disposed downstream of the spindle system and at least one outlet opening which is connected to the pressure region, the outlet opening discharging the delivery medium out of the pressure region. The second part includes at least one low-pressure chamber disposed upstream of the spindle system and at least one inlet opening for the delivery medium into the low-pressure chamber. The first part and the second part are coupled together, preferably in a rotational manner, so that they can assume at least two different relative positions.

Claims

1. A screw spindle pump, comprising: at least a first part and a second part, each for pumping delivery media such as lubricants, water, and suspensions; wherein the first part comprises a housing and at least one spindle system disposed in the housing and capable of being driven in a rotational manner, a pressure region disposed downstream of the spindle system and at least one outlet opening, which is connected to the pressure region, said outlet opening discharging a delivery medium out of the pressure region; wherein the second part comprises at least one low-pressure chamber disposed upstream of the spindle system and at least one inlet opening for the delivery medium into the low-pressure chamber; wherein the first part and the second part are configured to be coupled together in at least two different relative positions; and wherein the second part includes a valve in operative connection with the low-pressure chamber and the pressure region, the valve configured to produce a predefined maximum pressure level in the pressure region.

2. The screw spindle pump according to claim 1, wherein the second part of the screw spindle pump sits in a rotational manner on the first part.

3. The screw spindle pump according to claim 1, wherein a change from a first of the at least two different relative positions into a second of the at least two different relative positions is brought about by relative rotational movement of the first part with respect to the second part around a longitudinal axis, which longitudinal axis is constituted as a rotational axis of a male drive spindle of the spindle system.

4. The screw spindle pump according to claim 1, wherein a flange section for fixing to a corresponding mating flange is constituted in at least one of (i) the region of the inlet opening and (ii) the region of the outlet opening.

5. The screw spindle pump according to claim 1, wherein the first part comprises at least one return channel, which return channel is brought into fluidic communication with the pressure region and with the low-pressure chamber.

6. The screw spindle pump according to claim 5, wherein the at least one return channel is passed through the housing of the first part.

7. The screw spindle pump according to claim 5, wherein the at least one return channel runs parallel with a rotational axis of one or more spindles of the spindle system.

8. The screw spindle pump according to claim 1, the valve including a base body with a hollow space, in which a piston is mounted with a stroke motion against a restoring force of a compression spring, and at least one control bolt connected to the piston, the maximum cross-section of which control bolt is constituted reduced in area to the maximum cross-section of the piston and which guides the piston with a stroke motion against the restoring force of the compression spring in the base body when a predefined maximum pressure level in the pressure region is exceeded, wherein, resulting from the stroke motion, a lateral opening of the base body is cleared for a return flow of the delivery medium from the pressure region into the low-pressure chamber.

9. The screw spindle pump according to claim 8, wherein at least one bore is formed in a cover of the base body, wherein the cover is arranged at an end of the base body on an advancing side of a delivery direction, and wherein the cover comprises one or more further apertures for entry of the delivery medium into the hollow space of the base body.

10. The screw spindle pump according to claim 8, wherein, when the maximum pressure level in the pressure region is not exceeded, a head section of the piston is guided by the compression spring into a seat and the hollow space of the base body is brought into fluidic communication with the low-pressure chamber via the opening disposed laterally in the base body, so that the pressure level in the hollow space of the base body is essentially identical to the pressure level in the low-pressure chamber.

11. The screw spindle pump according to claim 8, wherein the base body comprises a rear cover, which is removable by one or more screw joints, said cover being disposed at an outer side of the second part.

12. The screw spindle pump according to claim 8, wherein the valve includes one or more adjusters for selecting the restoring force of the compression spring, said adjusters being accessible from an exterior.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Examples of embodiment of the invention and its advantages are explained in greater detail below with the aid of the appended figures. The size ratios of the individual elements with respect to one another in the figures do not always correspond to the actual size ratios, since some forms are represented simplified and other forms magnified compared to other elements for the sake of better clarity.

(2) FIG. 1 shows a diagrammatic perspective view of an embodiment of a spindle screw pump according to the invention;

(3) FIG. 2 shows a diagrammatic perspective view of the second part of the screw spindle pump from FIG. 1;

(4) FIGS. 3A-3B show a diagrammatic plan view and a diagrammatic side view of the second part from FIG. 2;

(5) FIGS. 4A-4B show a diagrammatic front view of the second part from FIGS. 2 and 3 as well as a cross-section through the second part;

(6) FIG. 5 shows a valve for adjusting a maximum pressure level in the pressure region of the screw spindle pump from FIG. 1;

(7) FIG. 6A-6B shows a possibility for the arrangement of the valve from FIG. 5 in a second part of an embodiment of a screw spindle pump according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(8) Identical reference numbers are used for identical or identically acting elements of the invention. Furthermore, for the sake of clarity, only reference numbers that are required for the description of the given figure are represented in the individual figures. The represented embodiments only represent examples as to how the screw spindle pump according to the invention can be constituted and do not represent a conclusive limitation.

(9) FIG. 1 shows a diagrammatic perspective view of an embodiment of a screw spindle pump 1 according to the invention. Screw spindle pump 1 is constituted by a first part 3 and a second part 5. First part 3 comprises a housing 7. Disposed in housing 7 is a spindle system 4, which in the present case comprises a male drive spindle 9 and two further female spindles, whereof one female spindle 10 can be seen in FIG. 1. First female spindle 10 and the further female spindles are coupled in a rotational manner with male drive spindle 9 and form, with an operative connection to the male drive spindle, moving delivery chambers for the transport of a delivery medium in delivery direction FR. Male drive spindle 9 is coupled at its free end 11 emerging from housing 7 of first part 3 with an actuator (not represented), such as for example an electric motor. Rotational axis R of male drive spindle 9 is also indicated.

(10) First part 3 comprises a pressure region 15 and an outlet opening 13, which is brought into connection with pressure region 15 thereby discharging the delivery medium from pressure region 15. The delivery medium thus flows from pressure region 15 and via outlet opening 13 out of housing 7 of first part 3. In the present case, pressure region 15 is defined as the region via which the delivery medium is passed on from spindle system 4 to outlet opening 13. In further embodiments, a screw spindle pump 1 can also comprise one or more pressure chambers, which are disposed upstream of outlet opening 13.

(11) The embodiment of FIG. 1 also comprises a return channel 21 as a component of screw spindle pump 14. Return channel 21 is constituted through housing 7 of first part 3 and is introduced as a bore into housing 7 during the production process of housing 7. Only one such return channel 21 is represented, but in other embodiments a plurality of such return channels 21 can also be introduced into housing 7.

(12) Return channel 21 connects pressure region 15 of first part 3 to low-pressure chamber 16 of second part 5, but is closed in the region of low-pressure chamber 16, so that the delivery medium cannot flow back from pressure region 15 into low-pressure chamber 16. As described in greater detail below in FIG. 6, the delivery medium is conveyed through return channel 21 into a pressure chamber 43 and respectively 43′, which is constituted as an annular channel, wherein a valve 2 (see FIG. 5) is connected to each pressure chamber 43 and 43′ respectively.

(13) FIG. 1 shows an embodiment in which outlet opening 13 is constituted as an outlet channel, wherein return channel 21 has an orthogonal orientation to the outlet channel and outlet opening 13 and is connected to outlet opening 13 and the outlet channel. The pressure region thus extends into outlet opening 13 and into the outlet channel. Return channel 21 runs as a bore parallel to rotational axis R of male drive spindle 9.

(14) Screw spindle pump 1 also comprises at least one low-pressure chamber 16 disposed upstream of spindle system 4, said low-pressure chamber being constituted shell-shaped in FIG. 1. By means of the shell-shaped embodiment, the flow behaviour of the delivery medium entering as a volume flow into low-pressure chamber 16 and its onward passage to spindle system 4 is optimised.

(15) An inlet opening 14 of second part 5 is also represented. The delivery medium enters via inlet opening 14 into low-pressure chamber 16. Disposed in the region of inlet opening 14 and in the region of outlet opening 13, in each case, is a flange section 18 and respectively 19 for fixing to a corresponding mating flange (not represented).

(16) First part 3 and second part 5 are coupled together in a rotational manner so they can assume two different relative positions. For this purpose, second part 5 sits in the present case on first part 3.

(17) FIG. 1 shows a first relative position of first and second part 3 and 5, wherein the delivery medium flows in a first flow direction SR1 through inlet opening 14 into low-pressure chamber 16 and in a second flow direction SR2 through outlet opening 13 out of housing 7 of first part 3, wherein first flow direction SR1 and a second flow direction SR2 run parallel with one another. Rotational axis R of male drive spindle 9 is also constituted as rotational axis D for the relative rotation of first and second part 3 and 5. Flange sections 18 and 19 of first and second part 3 and 5 can thus be matched, by means of a relative rotation of first and second part 3 and 5, to the position of a corresponding mating flange. A higher degree of flexibility with such an embodiment of a screw spindle pump 1 according to the invention is thereby ensured.

(18) FIG. 2 shows a diagrammatic perspective view of second part 5 of screw spindle pump 1 from FIG. 1. Flange section 18 and inlet opening 14 of second part 5 can again be clearly seen in FIG. 2. A valve 2 is also represented, which is also constituted as a component of second part 5 and which valve 2 will be dealt with below in detail in FIG. 5. Valve 2, inlet opening 14 and flange section 18 can be rotated together with second part 5 as a component of second part 5 with a relative rotational movement of first part 3 (see FIG. 1) with respect to second part 5.

(19) FIG. 3 show a diagrammatic plan view (FIG. 3A) and a diagrammatic side view (FIG. 3B) of second part 5 from FIG. 2. Flange section 18 and inlet opening 14 of second part 5 are again represented in FIG. 3A. A rear cover 23 and adjusting means 25 of valve 2 represented in detail in FIG. 5 can clearly be seen in FIG. 3. Rear cover 23 is disposed at an outer side of second part 5 and can be fixed there as appropriate by connections such as screws or suchlike and/or be accommodated in a form-fit manner in second part 5. The restoring force of compression spring 27 of valve 2 represented in FIG. 5 can be preselected or set by means of adjusting means 25, which is constituted accessible from the exterior and as an external square key.

(20) FIG. 4 show in FIG. 4A a diagrammatic front view of second part 5 from FIGS. 2 and 3. Also represented in FIG. 4B is a cross-section through second part 5 along intersecting line B-B in FIG. 4A.

(21) The cross-section of FIG. 4B again illustrates the arrangement of valve 2 in second part 5. As represented in FIG. 4B, low-pressure chamber 16 and the valve are brought into fluid communication with one another for passing on the delivery medium. The delivery medium can be passed on for example via a return channel 21 (see FIG. 1) to valve 2.

(22) FIG. 5 shows a valve 2 for adjusting a maximum pressure level in pressure region 15 of screw spindle pump 1. Valve 2 is constituted as a so-called pressure relief valve or safety valve. Valve 2 is a component of second part 5. With a relative rotation of first part 3 and of second part 5, a rotational movement of valve 2 together with second part 5 also takes place.

(23) With regard to its function, valve 2 is constituted in such a way that a predefined maximum pressure level in pressure region 15 can be produced by valve 2 when a predefined pressure level in pressure region 15 is exceeded.

(24) In the example of embodiment of FIG. 5, valve 5 comprises a base body 35 with hollow space H. In hollow space H, piston 31 is mounted with a stroke motion against the restoring force of a compression spring 27. A plurality of bores 44 are represented in a front cover 41 of base body 35, wherein the control bolt 39 passed through cover 41 guides piston 31 coaxially via the bore provided at the end face. In the present case, control bolt 39 is fixed by a central bore 44 in cover 41, wherein a plurality of further apertures or bores 44 are provided radially around the central bore in cover 41 of base body 35.

(25) As can be seen in FIG. 5, the maximum cross-section of bolt 39 normal to the respective longitudinal axis is constituted reduced in the area to the maximum cross-section of piston 31.

(26) Piston 31 also comprises a head section 33 at a free end pointing in the direction of bore 44. Head section 33 is accommodated play-free in hollow space H of base body 35 in the assembled state of valve 2 or of the pressure relief valve. A lateral opening 37 in base body 35 is also represented, past which lateral opening head section 33 of piston 31 is conveyed when a stroke motion is performed.

(27) Until the maximum pressure level in pressure region 15 is reached, piston 31 does not perform any stroke motion. Head section 33 is disposed in a seat S of front cover 41 as a result of a restoring force of compression spring 27. For example, seat S of front cover 41 can be such that head section 33 can be accommodated essentially play-free in seat S.

(28) The delivery medium can penetrate through lateral opening 37. The pressure level of the delivery medium penetrating into lateral opening 37 is always identical to the actual pressure level in low-pressure chamber 15 or in pressure region 15. If piston 31 performs a stroke motion due to the maximum pressure level being exceeded and head section 33 of piston 37 leaves seat S, delivery medium with the excess pressure can penetrate through return channel 21, bore 44 and radially provided openings of control bolt 39 and additionally assist the stroke motion of piston 31 against the restoring force of compression spring 27 in order to open, following the delivery medium, the path into hollow space H of base body 35 via opening 37 into low-pressure chamber 16.

(29) As already mentioned and as can be seen in FIGS. 3 and 4, rear cover 23 is disposed at the outer side of second part 5. The restoring force of compression spring 27 can be preselected by means of adjusting means 25.

(30) The individual components of valve 2 can be fitted together by means of fixing means 29 also represented in FIG. 5—in the present case constituted as screw joints.

(31) FIG. 6 show a possibility for the arrangement of valve 2 from FIG. 5 in a second part 5 of an embodiment of screw spindle pump 1 according to the invention

(32) FIG. 6A next illustrates by means of an arrow representation a possible option for the flow of the delivery medium. The delivery medium thus passes as a volume flow via inlet opening 14 into low-pressure chamber 16 of second part 5 and is then transported in the arrow direction via spindle system 4 (see FIG. 1) to outlet opening 13.

(33) The embodiment of FIG. 6 comprises two return channels 21 and 21′, which return channels 21 and 21′ have a parallel course. Each of return channels 21 and 21′ leads in the direction of a pressure chamber 43 and 43′ respectively, wherein a valve 2 as represented by way of example in FIG. 5 is connected to each chamber 43 and 43′ respectively.

(34) FIG. 6B also shows that the delivery medium can flow directly via opening 37 of valve 2 shown in FIG. 5 into low-pressure chamber 16 of second part 5. Furthermore, hollow space H of valve 2 or of base body 35 is in fluidic communication via opening 37 directly with low-pressure chamber 16.

(35) The invention has been described by reference to a preferred embodiment. The person skilled in the art can however imagine that modifications or changes to the invention can be made without thereby departing from the scope of protection of the following claims.