DE102007047682B4 - Method for pumping a liquid and positive displacement pump with two pumping chambers - Google Patents

Abstract

Positive displacement pump (10) having - a fluid chamber (12) and - in the fluid chamber (12) arranged movable partition (14) dividing the fluid chamber into a first pumping chamber (16) and into a second pumping chamber (18) such that a movement of the dividing wall (14) changes the volume of the first pumping chamber (16) and the volume of the second pumping chamber (18), the combined volume of the first pumping chamber and the second pumping chamber remaining constant, the fluid chamber (12) passing through a rotationally symmetrical housing (36) and a rigidly connected to the housing, radially from the inner wall of the housing to the axis of symmetry of the housing (36) extending radial wall (38) is defined, wherein the partition wall (14) radially from the inner wall of the housing (36) Symmetryeachse of the housing extends and is rotatable within a certain angular range about the axis of symmetry of the housing, characterized in that the housing (36) has a about the axis of symmetry of the G ehäuses rotatable end plate (40) having an end plate penetrating opening (50) or having a face plate penetrating valve.

Description

The invention relates to a positive displacement pump having a fluid chamber and a movable partition disposed in the fluid chamber dividing the fluid chamber into a first pumping chamber and a second pumping chamber such that movement of the dividing wall changes the volume of the first pumping chamber and the volume of the second pumping chamber wherein the combined volume of the first pumping chamber and the second pumping chamber remains constant, the fluidic chamber being defined by a rotationally symmetrical housing and a radial wall rigidly connected to the housing and radially extending from the inner wall of the housing to the symmetry axis of the housing extends radially from the inner wall of the housing to the axis of symmetry of the housing and is rotatable within a certain angular range about the axis of symmetry of the housing. The invention further relates to a fuel tank and a volumetric flow meter with the features of the positive displacement pump.

Reciprocating pumps are used inter alia as so-called metering pumps in motor vehicles for pumping fuel (gasoline or diesel) from a fuel reservoir into an injector. The pumping action is caused by the movement of a reciprocating piston in a cylinder. The volume change of the cylinder causes a flow movement in the fuel. Due to the known geometrical dimensions of the cylinder and the Kolbenverfahrweges and the low compressibility of the fuel while the funded volume per stroke is precisely defined. The reciprocating piston is typically driven by a magnetic field generated by an electrical coil. A spring, which is tensioned during the lifting process (retraction of the piston into the cylinder with simultaneous expulsion of fuel), moves the piston back after the lifting process, whereby the cylinder refills with fuel. Often, the fuel pump is installed in the fuel reservoir, where it is lapped by the fuel.

A disadvantage of such reciprocating pumps may be a periodic interruption of the delivered volume flow, the so-called fuel pulsation. This pulsation has its cause in that the reciprocating pump does not deliver fuel while the reciprocating piston moves back in the cylinder. Optionally (for example, in certain types of burners), the fuel pulsation must be eliminated or at least damped by a Fuelpulsationsdämpfer downstream of the Brenstoffpumpe. Another disadvantage is often an audible impact noise caused by the piston in its reversal of motion. In the passenger compartment, this noise can be perceived especially at low temperatures.

The US 5,437,542 A describes an improved positive displacement pump using a pair of counter-rotating pumps to provide a continuous and constant flow rate. However, a disadvantage of this pump is its complex construction, which combines two substantially independent pumps.

Rotary piston devices are in particular from the documents GB 402 818 A . DE 2 365 830 C3 . US 2,569,640 A . DD 93 301 A5 such as CH 413 602 A known.

The DE 2 365 830 C3 discloses a rotary piston internal combustion engine with rotatable face plate. Between four working chambers (pumping chambers) and a movable rotary valve a fixed side part is provided. The fixed side panel, the movable rotary valve and the fixed face plate together form a frontal closure of the working chambers.

The DE 10 2005 028 953 A1 describes a fuel pump system for supplying fuel from a fuel tank to an internal combustion engine. The system may include a fuel pump with a positive displacement pumping element.

A method of pumping a liquid may include the step of increasing the volume of a first pumping chamber and simultaneously reducing the volume of a second pumping chamber by advancing a partition wall separating the first pumping chamber from the second pumping chamber. The term "pumping chamber" here and in the following always means a spatial region in which a part of the fluid to be pumped is temporarily enclosed before this part is expelled again from the pumping chamber by a movement of the dividing wall. The inventive method is based on the recognition that a change in volume of two separate pumping chambers can be achieved by the movement of a common partition wall separating the pumping chambers, eliminating the need to provide each of the two pumping chambers with their own separate piston or similar element. As the volume of the first pumping chamber increases, while the volume of the second pumping chamber decreases, additional fluid can be stored in the first pumping chamber during the ejection of fluid from the second pumping chamber after the end of the step, preferably when the second pumping chamber is in the first pumping chamber is essentially empty, to continue the pumping process is available.

In this connection, it is preferred that the method further comprises the step of: increasing the volume of the second pumping chamber and simultaneously reducing the volume of the first pumping chamber by moving the partition backward. In this step, the fluid collected in the described first step in the first pumping chamber is expelled. A cyclic repetition of the two described steps enables a quasi-continuous volume flow of the fluid during pumping, whereby it should be understood as quasi-continuous that the volume flow in each cycle can at the moment be greatly reduced, during a period of time which is much shorter than the period of the cycle. For example, it is possible that the volume flow is interrupted briefly when the partition reverses its movement.

• – Unterbrechen einer Fluidleitung zwischen einem Eingangsreservoir und der ersten Pumpkammer,
• – Unterbrechen einer Fluidleitung zwischen der zweiten Pumpkammer und einem Ausgangsreservoir,
• – Herstellen einer Fluidleitung zwischen dem Eingangsreservoir und der zweiten Pumpkammer,
• – Herstellen einer Fluidleitung zwischen der ersten Pumpkammer und dem Ausgangsreservoir.

It is considered particularly advantageous that between the step of increasing the volume of the first pumping chamber and the step of increasing the volume of the second pumping chamber, the following steps are carried out:

• Interrupting a fluid line between an inlet reservoir and the first pumping chamber,
• Interrupting a fluid line between the second pumping chamber and an outlet reservoir,
• Establishing a fluid line between the inlet reservoir and the second pumping chamber,
• - Establishing a fluid line between the first pumping chamber and the outlet reservoir.

The interruption or production of the respective fluid line can be done, for example, by opening or closing a valve.

It is further considered advantageous that the combined volume of the first pumping chamber and the second pumping chamber remains constant throughout the process. This can be advantageous if the volume of the fluid not contained in the pump should remain constant, for example for measurement purposes.

It is an object of the invention to provide a space-saving positive displacement pump which provides a substantially continuous volume flow and can be used as a metering pump for pumping incompressible liquids or as a volumetric flow meter. This object is achieved with the features of the independent claims. Advantageous embodiments will be apparent from the dependent claims.

The displacement pump according to the invention builds on the prior art, characterized in that the housing has a rotatable about the axis of symmetry of the housing face plate with a front plate penetrating opening or with a face plate penetrating valve. Since one pumping chamber receives fluid while the other pumping chamber delivers fluid, only one output valve and one inlet valve for a fluid chamber are needed at a given moment. A rotatable faceplate makes it possible to automatically connect an outlet valve (an inlet valve) to the pumping chamber from which fluid is to exit (enter). The partition can be driven via a rotating shaft along the axis of the housing, in particular by an electric motor. This eliminates a conversion of rotational movement in translational motion.

It is particularly preferred that the positive displacement pump has an electric motor for driving the dividing wall. The electric motor is coupled to the dividing wall so as to allow cyclical movement of the dividing wall.

According to a preferred embodiment, the first pumping chamber and the second pumping chamber each have an input valve and / or an outlet valve. Through the input valve (output valve), the fluid can only flow in (outflow), but not outflow (inflow). This allows pumping of the fluid from a low pressure input reservoir to a higher pressure output reservoir. A simple form of an input valve is z. B. an opening in the pumping chamber with a flap attached to the inner wall of the pumping chamber, which closes when the internal pressure of the pumping chamber is greater than the pressure on the outside of the flap.

In this context, it is considered advantageous that the end plate is designed to be at least temporarily rotated by the rotatable partition in rotation. Thus, a simple mechanism is provided to position the valve at the desired pumping chamber.

According to a particularly preferred embodiment, it is provided that the length of the housing, measured parallel to the axis of symmetry, is at least four times as large as the diameter of the housing. Such a lance-like shape is advantageous for the installation of the pump in a fuel tank or swirl pot.

The advantages of the invention can also be transferred to a volumetric flow meter, which in construction substantially coincides with the pump according to the invention. When using the pump as a volumeter, the partition wall is driven by the fluid flowing through, the number of movement cycles per unit time allows a conclusion on the flow rate.

The invention will now be described by way of example with reference to the accompanying drawings.

Show it:

1 a schematic three-dimensional view of a pump which is connected between an input reservoir and an outlet reservoir;

2 a schematic section through the pump 1 while the dividing wall of the pump is moved forward;

3 a schematic section through the pump 1 while the partition wall of the pump is moved backward;

4 a flowchart of a method for pumping a fluid;

5 an exploded view of an embodiment of the inventive pump;

6 to 9 each a plan view of each one of the elements in 5 illustrated pump;

10 to 13 a cross section of the pump 5 to different phases pumping cycle;

14 a swirl pot with a pump according to the invention; and

15 a diesel burner with a pump according to the invention.

In the figures, the same or similar reference numerals (for example 14 and 14 ' ) identical or similar components, which are at least partially explained only once to avoid repetition.

In the 1 illustrated pump 10 includes a fluid chamber 12 , which is shown transparent for the sake of clarity, and which is limited by an unillustrated housing. The fluid chamber 12 is through a partition 14 in a first pumping chamber 16 and into a second pumping chamber 18 divided. The partition 14 is firmly with a the fluid chamber 12 continuous reciprocating piston 32 connected or integrally formed with him. The partition 14 can by means of power transmission through the reciprocating piston 32 along with the reciprocating piston along the axis of the reciprocating piston (directions F and B) are moved back and forth, z. B. by an electric motor, not shown. By moving the partition in the forward direction F, the volume of the first pumping chamber 16 increases and the volume of the second pumping chamber 18 reduced. The first pumping chamber is via a first input fluid line 24 and via a first output fluid line 30 with an entrance reservoir 20 or with an outlet reservoir 22 connected. The second pumping chamber is correspondingly via a second input fluid line 28 and via a second output fluid line 26 with the entrance reservoir 20 or with the output reservoir 22 connected. Within the two input lines ( 24 . 28 ) are arranged valves (not shown), which cause fluid to the input lines ( 24 . 28 ) only in the direction of the entrance reservoir 20 to the fluid chamber 20 , but not in the opposite direction, can flow through. Within the two output lines ( 26 . 30 ) are arranged valves (not shown), which cause a liquid, the output lines ( 26 . 30 ) only in the direction of the fluid chamber 12 to the exit reservoir 22 , but not in the opposite direction, can flow through.

The one by the pump 10 enabled pumping cycle is through the below described 2 and 3 schematically illustrated, wherein the black arrows each indicate the flow of the fluid.

2 represents the phase of the pumping cycle in which the partition wall 14 over the piston 32 is moved in the forward direction F. In this case, fluid flows from the input reservoir 20 due to its own pressure through the first input line 24 in the first pumping chamber 16 , A backflow of fluid from the second pumping chamber 18 through the second input line 28 is prevented by the in the input line 28 located valve (not shown). At the same time, fluid flows out of the second pumping chamber 18 through the second output line 26 in the exit reservoir 22 , wherein the pressure of the fluid in the outlet reservoir 22 may be higher than the pressure of the fluid in the inlet reservoir 20 , A backflow of the fluid from the outlet reservoir 22 through the first output line 30 in the first pumping chamber 16 is prevented by a in the output line 30 arranged valve (not shown).

3 outlines the second phase of the pumping cycle, in which the dividing wall 14 is moved in the reverse direction B. The second phase of the pumping cycle is analogous to the first one. Now fluid flows from the input reservoir 20 through the second input line 28 into the second pumping chamber, and fluid flows from the first pumping chamber 16 through the first output line 30 in the exit reservoir 22 wherein a backflow of fluid through the second exit conduit 26 and the first input line 24 through inside the pipes ( 24 . 26 ) arranged valves is prevented.

It is noted that both in the forward movement F and in the backward movement B of the partition wall 14 Fluid is promoted, in the sense that fluid from the pump 10 from the entrance reservoir 20 is sucked while at the same time fluid in the outlet reservoir 22 is ejected.

The under reference name 3 and 4 Pump cycle explained is schematically in the flow chart 4 played. The partition 14 is moved forward in a first step S1, wherein fluid is conveyed. Then the partition wall 14 moved back in a second step S2, wherein also fluid is conveyed. Only at the moment when the partition is resting (in the transition from the first step S1 to the second step S2) is no fluid conveyed. After step S2, it is decided whether to continue pumping. If so, the process returns to step 1; if not, it ends.

5 shows the basic structure of a positive displacement pump according to the invention 10 in its preferred embodiment. Particularly advantageous in this embodiment is that the pump can be designed very elongated (tubular or lance-shaped), during which pumping fluid is pumped from an input end of the pump to an output end. The pump 10 comprises a tubular rotationally symmetrical housing 36 with disc-shaped end plates 40 and 42 that the case 36 complete at opposite ends. The first face plate 40 has outlet openings for the discharge of fluid from the pump (see 8th ). The second face plate 42 In contrast, has inlet openings for receiving fluid in the pump. The housing 36 has two integral with the housing 36 formed radial walls 38 and 38 ' on, each radially from the housing 36 to the symmetry axis of the housing 36 extend and with the housing a first fluid chamber 12 and a second fluid chamber 12 ' define. A rotor 34 with two flat, wall-shaped wings 14 . 14 ' is about the symmetry axis of the rotationally symmetrical housing 36 rotatably mounted, such that the two wings 14 . 14 ' radially from the rotor 34 to the inner wall of the housing 36 extend. The wing 14 divides the first fluid chamber 12 in a first pumping chamber 16 and into a second pumping chamber 18 how in more detail 10 to 13 can be seen. According to the wing shares 14 ' the second fluid chamber 12 ' in a third pumping chamber 16 ' and into a fourth pumping chamber 18 ' , A rotary oscillator 44 with a fixed magnetic stator 48 and a rotatable magnet rotor 46 is part of an electric motor, not shown, for driving the rotor 34 , The housing 36 , the rotor 34 , the forehead plate 40 and the rotary oscillator 44 are in the following 6 . 7 . 8th and 9 shown enlarged.

6 is a cross section through the tubular, rotationally symmetrical housing 36 out 5 , The two radial walls 38 and 38 ' are offset by 180 ° on the inner wall of the housing 36 arranged and extend from the inner wall radially inwardly. One between the ends of the radial walls 38 and 38 ' occurring free space, the axis of symmetry of the housing 36 surrounds, serves to accommodate the rotor 34 ,

7 is a cross section through the rotor 34 out 5 , The wings 14 and 14 ' are arranged offset by 180 ° on the rotor and each define a plane extending perpendicular to the cross-sectional plane.

8th is a cross section through the face plate 40 out 5 , The face plate 40 has a circular cross-section and has two radially spaced outlet openings 50 and 50 ' , which preferably each contain an outlet valve. The face plate 40 still has four pens 52 . 54 . 52 ' . 54 ' Standing vertically on the face plate 40 are mounted and form the vertices of a rectangle. The entire face plate 42 including outlet openings 50 and 50 ' and pins 52 . 54 . 52 ' . 54 ' is symmetrical with respect to a reflection at the through the outlet openings 50 and 50 ' current axis. The second face plate 42 out 5 is analogous to the front plate 40 built, using instead of the outlet openings 50 . 50 ' having corresponding inlet openings.

9 illustrates the rotary oscillator 44 out 5 , A movable magnet rotor 46 is rotatable between a magnetic stator 48 arranged. Both the magnet rotor and the magnet stator are magnetized and interact with each other in a magnetic interaction, so that in the idealized smooth case of the magnet rotor 46 performs an oscillating rotational movement, characterized in that between the magnetic rotor 46 and the rest axis A oscillates formed angle α. The rotor is used to clock the pump 10 used.

The functioning of in 5 illustrated pump 10 will now be referring to 10 . 11 . 12 and 13 explained in more detail.

10 illustrates the phase in which the wing 14 (as well as the analog wing 14 ' ) in the reverse direction B, B 'is rotated. In this phase, the volume of the first pumping chamber decreases 16 while the volume of the second pumping chamber 18 increases accordingly. Fluid leaves the first pumping chamber 16 through the outlet opening 50 the face plate 40 while at the same time fluid through a (not shown, in the back of the viewer lying) inlet opening of the face plate 42 in the second pumping chamber 18 flows. At a certain angle the wings touch 14 and 14 ' the pencils 52 respectively. 52 ' and thereby rotate the face plate 40 together with the pins 52 . 52 ' . 54 . 54 ' and outlet openings 50 . 50 ' , The only in 5 illustrated second face plate is as well as the first face plate 40 over the wings 14 . 14 ' moved. Due to the rotational inertia of the face plate 40 and / or due to the wing 14 . 14 ' on the pins 52 . 52 ' applied torques rotate the face plate 40 until the outlet opening 50 in between the radial wall 38 and the wing 14 ' sector. The outlet opening 50 ' Appropriately enters the between the radial wall 38 ' and the wing 14 lying sector. Now the pumping chambers 16 . 16 ' With no outlet opening in contact anymore, the rotation of the wings becomes 14 . 14 ' in the case of an incompressible fluid immediately steamed very heavily, leaving the wings 14 . 14 ' come to a standstill.

This results in the in 11 illustrated constellation. It corresponds to the moment in which the rotary motion of the grand piano 14 is reversed, so that the wing is currently resting. Now the pumping chambers 18 and 18 ' each with one of the outlet openings 50 ' . 50 connected while the pumping chambers 16 and 16 ' each with an inlet opening of the non-visible in the figure second end plate 42 are connected.

After the in 11 The following constallation follows the in 12 illustrated pumping phase. The wings 14 . 14 ' are now rotated forward F, F ', with fluid passing through the second faceplate 42 (not visible in the figure) in the first pumping chamber 16 flows while at the same time fluid from the second pumping chamber 18 through the outlet 50 ' the first face plate 40 flows. At a certain angle of rotation, the wings turn 14 and 14 ' over the pins 54 and 54 ' the first face plate until finally the in 13 shown inversion constellation results in the inlet and outlet openings have changed their position again with respect to the pumping chambers.

13 illustrates the moment of motion reversal of the wings 14 . 14 ' , The illustrated constellation is analogous to 11 , After the reversal of motion (change from the forward rotation F, F 'to the reverse rotation B, B'), the in 10 illustrated pumping phase, whereby the cycle is repeated.

Alternatively, the face plates 40 and 42 (please refer 5 and 8th ) also fixed, that is non-rotating, be trained. In this alternative embodiment, the first end plate has a total of four instead of two outlet openings, preferably with integrated outlet valves. The second face plate has correspondingly four inlet openings, preferably with integrated inlet valves.

14 schematically shows a swirl pot according to the invention 62 for supplying a motor vehicle with fuel. The lance-shaped positive displacement pump according to the invention 10 (please refer 5 ) is integrated in the swirl pot and is surrounded by fuel. The pump 10 is powered by a drive unit 56 , preferably an electric motor, driven. The one from the Schwalltopf 62 subsidized fuel is via one on the drive unit 56 attached fuel line 58 passed. Alternatively, the pump can also be installed so that both the drive unit 56 as well as the pump 10 be lapped by the fuel.

15 schematically shows a diesel burner 64 with inventive positive displacement pump 10 for introducing diesel into the burner 64 , The diesel enters via a supply line 58 and a drive unit 56 into the pump 10 one, the diesel to a burner fleece 60 emits.

LIST OF REFERENCE NUMBERS

F

forward direction

B

reverse direction

10

displacement

12

fluid chamber

14

partition wall

16

first pumping chamber

18

second pumping chamber

20

input reservoir

22

output reservoir

24

first input fluid line

26

second input fluid line

28

first output fluid line

30

second output fluid line

32

reciprocating

34

wave

36

casing

38

radial wall

40

first face plate

42

second face plate

44

rotary oscillator

46

magnet rotor

48

magnetic stator

50

outlet opening

52

pen

54

pen

56

power unit

58

fuel line

60

Brenner fleece

62

swirl pot

64

diesel burner

Claims (7)

Positive displacement pump ( 10 ) with - a fluid chamber ( 12 ) and - one in the fluid chamber ( 12 ) arranged movable partition ( 14 ), the fluid chamber into a first pumping chamber ( 16 ) and into a second pumping chamber ( 18 ), such that movement of the partition wall ( 14 ) the volume of the first pumping chamber ( 16 ) and the Volume of the second pumping chamber ( 18 ), wherein the combined volume of the first pump chamber and the second pump chamber remains constant, the fluid chamber ( 12 ) by a rotationally symmetrical housing ( 36 ) and a rigidly connected to the housing, radially from the inner wall of the housing to the axis of symmetry of the housing ( 36 ) extending radial wall ( 38 ), wherein the partition wall ( 14 ) radially from the inner wall of the housing ( 36 ) extends to the symmetry axis of the housing and is rotatable within a certain angular range about the axis of symmetry of the housing, characterized in that the housing ( 36 ) a rotatable about the symmetry axis of the housing end plate ( 40 ) with an opening penetrating the face plate ( 50 ) or having a valve penetrating the face plate. Positive displacement pump ( 10 ) according to claim 1, characterized in that the positive displacement pump ( 10 ) an electric motor ( 56 ) for driving the partition wall ( 14 ) having. Positive displacement pump ( 10 ) according to claim 1, characterized in that the first pumping chamber ( 16 ) and the second pumping chamber ( 18 ) each have an input valve and / or an output valve. Positive displacement pump ( 10 ) according to claim 1, characterized in that the end plate is designed, at least temporarily by the rotatable partition ( 14 ) to be set in rotation. Positive displacement pump ( 10 ) according to claim 1, characterized in that the length of the housing ( 36 ), measured parallel to the symmetry axis, at least four times as large as the diameter of the housing. Fuel tank in which a positive displacement pump ( 10 ) is installed according to claim 1. Volumetric flow meter ( 10 ) with - a fluid chamber ( 12 ) and - one in the fluid chamber ( 12 ) arranged movable partition ( 14 ), the fluid chamber into a first pumping chamber ( 16 ) and into a second pumping chamber ( 18 ), wherein a movement of the partition ( 14 ) the volume of the first pumping chamber ( 16 ) and the volume of the second pumping chamber ( 18 ), wherein the combined volume of the first pumping chamber and the second pumping chamber remains constant, characterized in that the fluid chamber ( 12 ) by a rotationally symmetrical housing ( 36 ) and a rigidly connected to the housing, radially from the inner wall of the housing to the axis of symmetry of the housing ( 36 ) extending radial wall ( 38 ), wherein the partition wall ( 14 ) radially from the inner wall of the housing ( 36 ) extends to the symmetry axis of the housing and is rotatable within a certain angular range about the axis of symmetry of the housing.

Images