TW202219387A - Liquid blade pump - Google Patents

Abstract

A pump for pumping a gas, the pump comprising: a rotor and a stator; the rotor comprising at least one liquid opening configured for fluid communication with a liquid source. The liquid opening is configured such that in response to a driving force a stream of liquid is output from the opening, the stream of liquid forming a liquid blade between the rotor and the stator, gas confined by the stator, the rotor and the liquid blade being driven through the pump along a pumping channel from a gas inlet towards a gas outlet in response to relative rotational motion of the rotor and the stator. A cross sectional area of the pumping channel is configured to increase from the gas inlet to the gas outlet.

Description

Liquid Vane Pump

The field of the invention is that of pumps.

Different types of pumps are known for pumping gases. These include entrapment pumps, in which a gas is trapped on a surface inside the pump before being removed; power or momentum transfer pumps, such as turbomolecular pumps, in which the molecules of the gas move from the inlet side towards the outlet or exhaust side acceleration; and a positive displacement pump in which gas is trapped and moves from the inlet towards the outlet of the pump.

Positive displacement pumps provide moving pumping chambers typically formed between one or more rotors and a stator, the movement of the rotors causing the effective pumping chambers to move. Gas received at the inlet enters and is trapped in the pumping chamber and moves to the outlet. In some cases, the volume of the gas bladder is reduced during movement to improve efficiency. These pumps include Rouge pumps and rotary vane pumps. To draw gas into the chamber, the chamber typically expands and to expel gas from the chamber, the chamber volume typically contracts. For example, this volume change can be accomplished in rotary vane pumps by using means such as springs (which themselves tend to wear out) with vanes extending in and out of the pump chamber or in rouge or progressive cavity pumps using two synchronized rotors that cooperate with each other And the stator is accomplished by moving the gas pocket and creating a volume change between the inlet and the outlet. An additional rotor requires an additional shaft, bearings, and timing methods (such as gears) to synchronize rotor movement.

Furthermore, in order to minimize or at least reduce leakage and effectively move the gas when it is trapped, the moving parts need to form a tight seal with each other and with the static parts that form the trapped volume of the gas. Some pumps use a liquid (such as oil) to seal between the surfaces of the trapped volume, while others rely on tight non-contacting gaps, which can result in increased manufacturing costs and can also be Pumps susceptible to locking or seizing due to the presence of particles or impurities in the fluid.

GB2565579 discloses a pump that uses a liquid to form pump vanes and thereby solves some of the above problems.

It would be desirable to provide a pump that is wear resistant, provides low power consumption and a relatively small pumping mechanism, is relatively inexpensive to manufacture and operate, and provides an efficient method of pumping gas between an inlet and an outlet.

A first aspect provides a pump for pumping gas, the pump comprising: a rotor and a stator; at least one of the rotor or stator comprising at least one liquid opening configured for contact with a liquid source fluid communication; the liquid opening is configured such that in response to a driving force, a flow of liquid is output from the opening, the liquid flow forming a liquid vane between the rotor and the stator by the stator, the rotor and the Gas confined by liquid vanes is driven through the pump along a pumping channel from a gas inlet toward a gas outlet in response to relative rotational motion of the rotor and the stator; wherein a cross-sectional area of the pumping channel is structured shape to increase from the gas inlet to the gas outlet.

The inventors of the present invention have recognized that the elements of a pump are configured with liquid opening(s) such that the liquid output through the openings forms a surface or vane between the elements of the pump, which then opposes one of the elements. While the other is rotating, the liquid vane can be used to drive gas through the pump. Such a liquid vane is inherently deformable, low cost, and capable of providing a good seal between the surfaces of the entrapment volume without tight manufacturing tolerances. Furthermore, such a blade itself does not suffer from wear and provides very little wear on the surfaces it contacts.

However, since the vanes are formed from a flowing liquid, the fluid forming the vanes is constantly replenished. One of the challenges of pumps using liquid vanes is maintaining sufficient free volume within the pumping channel for gas movement as the liquid forming the liquid vane accumulates in the channel during operation. Typically, the cross-sectional area of the pumping channel is configured to decrease between the inlet and outlet to provide compression of the gas during pumping, resulting in a more efficient pump. Embodiments provide an increase in a cross-sectional area between the inlet and the outlet. This increase serves to compensate for the reduction in the volume of gas available for pumping due to the accumulation of liquid in the pumping channel due to the constantly replenished liquid vanes. As the liquid is discharged along the channel, the accumulation of liquid increases from the inlet to the outlet, and thus an increase in the cross-sectional area from the inlet to the outlet can be used to solve this problem and provide an acceptable volume change from the inlet to the outlet, This provides a desired pumping speed and acceptable efficiency.

In some embodiments, a distance between the rotor and the stator increases from the gas inlet to the gas outlet.

One way in which the cross-sectional area can be increased is to increase a distance between the rotor and the stator. This can be done by shrinking one or the other or both. A potential problem with this is that the length of the liquid vanes also increases as the distance between the rotor and stator increases, and this can make it less robust. This reduction in robustness may require some additional measures, such as increasing liquid flow to maintain an acceptable vane.

In some embodiments, the pump is configured such that during operation, the amount of liquid output through the liquid opening increases from the gas inlet to the gas outlet.

The amount of liquid input through the liquid opening may increase from the gas inlet towards the gas outlet. This can be advantageous for several reasons. First, any liquid entering the vicinity of the gas inlet may need to travel along the pumping channel for discharge and therefore, it is advantageous to limit the amount of liquid entering the vicinity of the inlet, as this may need to travel along most of the length of the pumping channel and at The liquid within the pumping channel reduces the available volume for the gas being pumped. Furthermore, in an embodiment, as the distance between the stator and the rotor increases from the inlet to the outlet, in order to make the liquid vanes more robust (wherein the liquid vanes cover a larger area), it is advantageous if additional liquid is supplied of. In this regard, the increase in blade length can be compensated for by a corresponding increase in the amount of water supplied, while maintaining the same robust blade.

In some embodiments, the cross-section of the liquid opening towards the gas outlet is greater than its cross-section towards the gas inlet.

An increase in the amount of liquid introduced through the liquid opening can be achieved by increasing the cross-section of the liquid opening towards the gas outlet. Alternatively, it can be achieved by increasing the exit velocity of the liquid at the slit. Increasing the width of the slit is more energy efficient than increasing the speed at which the water leaves. However, there is still a power loss associated with the increase in water forming the water vanes.

In some embodiments, the liquid opening includes a slit.

An elongated opening in the form of a slit provides an efficient water blade. In some embodiments, instead of a single long, narrow opening, there may be a plurality of liquid openings arranged along a line, the liquid from each opening coalescing with liquid from adjacent openings to form a vane along the line.

Although in some embodiments the slits may be angled relative to a longitudinal axis, the slits extend longitudinally parallel to one of the axes of rotation of the rotor.

In some embodiments, if the distance between the rotor and the stator increases from the gas inlet to the outlet by shrinking either the rotor or the stator, then a slit is attached to the liquid opening and the slit may have a point towards the gas outlet. With an increased width (in which the distance between the rotor and the stator is increased), a blade of increased thickness and correspondingly increased robustness is provided.

In other embodiments, the slot is configured in a helix extending around a rotational axis of the rotor.

A helical pumping channel can be defined by helical slits forming a helical liquid vane.

In some embodiments, the angle of the helix varies from the gas inlet toward the gas outlet such that the pitch of the helix increases toward the gas outlet.

An increase in the cross-sectional area of the pumping channel can be achieved by increasing the pitch of the helical liquid opening from the inlet to the outlet. In this way, the problem of increasing the distance between the rotor and the stator does not arise and no additional liquid is required to maintain the robustness of the liquid vanes.

The slit can be a single aperture extending along a linear or helical path, or it can be formed by a plurality of apertures arranged along a linear or helical path.

In some embodiments, one of the rotor and the stator includes a helical protrusion extending toward the other element including the liquid opening and defining a helical path of the pumping channel.

One form of pump using a liquid vane may be a progressive cavity pump having a helical path formed by helical protrusions extending between the rotor and the stator.

In some embodiments, the pitch of the helical protrusion increases from the gas inlet to the gas outlet.

An alternative method of increasing the cross-sectional area of the pumping channel is to increase the pitch of the helical protrusions. This can be advantageous because then the distance between the rotor and the stator can be kept constant and therefore the amount of liquid required by the liquid vanes extending through the same cross-sectional area of the liquid opening can be kept constant.

In some embodiments, the cross-sectional area of the pumping channel is determined by a radial length (which is a distance between the rotor and the stator) and an axial width (which is perpendicular to the radial length of the pump) A dimension of the feed channel) defines the axial width increasing from the gas inlet to the gas outlet.

As previously mentioned, if the radial length of the pumping channel increases, it may be necessary to increase the amount of liquid supplied in order to maintain a robust vane. If the axial width of the channel is increased, the size of the liquid opening (when it covers the width of the pumping channel) will automatically increase accordingly without any further adjustment. Therefore, the axial width can be expected to increase from the gas inlet to the gas outlet. In this regard, the axial width is parallel to the axis of rotation.

In some embodiments, one of the rotor and the stator is mounted within the other.

In some embodiments, the rotor includes the liquid opening and is mounted for rotation within the stator.

In some embodiments, the stator and rotor are configured such that the pumping channel runs around a circumference of the rotor or an interior of one of the stators, and the gas inlet is configured to be vertically higher than the gas outlet in operation.

Since the liquid forming the liquid vanes will flow down the channel as it hits the walls of the pumping channel and collect in the bottom of the channel, there should be some discharge of the liquid from the pumping channel if the pumping channel is not filled with liquid method. In some cases, the pumping channel is configured such that when the pump is in operation, the lower surface of the gas inlet is higher than the lower surface of the gas outlet so that liquid will exit through the gas outlet. In some embodiments, the pumping channel runs a single pass around the circumference of the stator, or in fact slightly less than one full revolution around one of the circumferences.

In some embodiments, a lower surface of the pumping channel at the gas outlet is lower than a lower surface of the pumping channel at the gas inlet, and a higher surface of the pumping channel at the gas outlet is higher than A lower surface of the pumping channel at the gas inlet.

The liquid vanes push the gas in a substantially circumferential direction along the direction of rotation of the rotor. It is therefore advantageous if the pumping channel and the gas outlet are also arranged along this path. Therefore, although the gas outlet should be lower than the gas inlet to allow discharge of the liquid, it is advantageous if the gas outlet is only slightly lower than the gas inlet so that the gas is effectively driven by the liquid vane as it rotates.

In some embodiments, the pump further includes a sealing member between the side wall and the rotor or stator including the liquid opening.

To reduce leakage of gases and liquids, sealing members may be provided between the side walls of the pumping channel and the rotor or stator including the liquid openings. In this regard, if the width of the pumping channel decreases from the gas inlet to the gas outlet, near the gas inlet, the liquid openings will extend beyond the width of the narrower pumping channel and thus provide a reduction in the exit(s) of the liquid openings. It is advantageous to have a portion of the liquid volume that does not lead to the sealing member of the narrower channel near the inlet.

In some embodiments, a cross-sectional area of the pumping channel is determined by a radial length (the radial length being a distance between the rotor and the stator) and an axial width (the axial width being vertical The pump is configured such that the axial width of the pumping channel decreases with increasing radial distance from the liquid opening, as defined by a dimension of the pumping channel in the radial length.

In some embodiments, the pumping channel may be tapered such that it narrows away from the liquid opening. When the liquid vanes leave the liquid opening(s), the liquid vanes themselves may taper and therefore it may be advantageous to reduce the channels in a corresponding manner and thereby avoid or at least reduce the gaps formed between the side walls and the vanes.

In some embodiments, the pump is configured such that the cross-sectional area from the gas inlet to the gas outlet increases and the amount of liquid supplied to the pump to form the liquid vanes in normal operation is selected such that it is available for gas A cross-sectional area of the pumping channel decreases from the gas inlet to the gas outlet, and the pumped gas is compressed.

The volume of gas available for pumping depends on both the cross-sectional area of the pumping channel and the liquid within the pumping channel. The liquid in the pumping channel will increase from the inlet to the outlet and can be determined from the liquid supplied to the pump and its drainage rate during normal operation. The pump may be configured such that the increase in cross-sectional area from the gas inlet to the gas outlet of the pumping channel is selected depending on the estimated amount of liquid that will accumulate in the pumping channel during normal operation. In this way, the cross-sectional area of the pumping channel available for gas can be controlled and, in some cases, controlled to decrease slightly from the gas inlet to the gas outlet so that the gas being pumped is compressed.

In summary, the liquid supplied to the pump through the liquid openings to form the liquid vanes will accumulate within the pump from the gas inlet to the gas outlet and be discharged with the gas at the gas outlet. This will result in an increase in liquid along the pumping channel from the gas inlet to the gas outlet and a corresponding decrease in the usable area of the pumped gas. This can be compensated for by an increase in the cross-sectional area of the pumping channel from the gas inlet to the gas outlet. In some cases, the pump is configured such that the two are connected to each other, and the design is such that the free volume of gas decreases from the pump inlet to the pump outlet such that there is compression of the pumped gas, the reduction being controlled to provide a controllable The amount of compression, which allows an efficient pump with an efficient liquid vane.

In this regard, the increase in cross-sectional area may be a gradual increase along one of the lengths of the pumping channel such that it is linked to the accumulation of liquid within the pumping channel.

In some embodiments, the pump includes a vacuum pump.

Further specific and preferred aspects are set forth in the accompanying independent and dependent claims. The features of the dependent technical solution may be combined with the features of the independent technical solution as appropriate, and may be combined differently from the combinations expressly stated in the claims.

Where a device feature is described as being operable to provide a function, it should be understood that this includes one device feature that provides that function or is adapted or configured to provide that function.

Before discussing the embodiments in more detail, an overview will first be provided.

Embodiments of the pump create a rotating sheet of water to separate the pumped gas into discrete volumes and drive these volumes from the inlet to the outlet. During the passage from inlet to outlet, an increasing volume of water is introduced into the mechanism until at the outlet, both water and gas exit at the exhaust. One of the technical challenges is maintaining sufficient free volume for gas to move through the mechanism. This can be solved by increasing the cross-sectional area of the channel through which the gas moves. One approach to solving this problem while reducing power consumption is to increase the cross-sectional area depending on the distance from the inlet, which in some embodiments depends on the angle of rotation.

Embodiments of the pump include a hollow cylindrical rotor that brings water out of the sump and through vertical slits to create a rotating sheet of water. These sheets of water separate the pumped gas into discrete volumes and drive these volumes from the inlet to the outlet. In one embodiment, these discrete volumes are created within the thread and the gas is driven down the helical channel. In another embodiment, the discrete volumes are defined only by an upper and lower sealing edge and are driven radially from the inlet to the outlet in a mechanism similar to a rotary vane pump. In yet another embodiment, the liquid openings themselves are threaded, providing helical liquid vanes for pumping gas from the inlet to the outlet.

In all these embodiments, the continuous increase in liquid volume from inlet to outlet typically introduces water into the mid-mechanism until at the outlet, both water and gas exit at the exhaust. Therefore, one of the technical challenges is maintaining sufficient free volume for gas to move through the mechanism. This can be achieved by increasing the height of the channel through which the gas moves and/or increasing the cross-sectional area of the channel by increasing the radial distance between the rotor and stator walls.

However, only uniformly increasing the cross-sectional area can be inefficient in terms of energy consumption, and provides only limited control over changes in the sealed gas volume. In some embodiments, the amount of increase in cross-sectional area is set to depend on the amount of liquid added and any desired compression. Liquid vanes are constantly replenished and the vane-forming liquid will accumulate in the pumping channel, reducing the volume available for the gas being pumped. This is predictable and the design can be estimated due to the volume change of the accumulated liquid and the desired compression and the design, corresponding increase in cross-sectional area.

In one embodiment, an energy saving method is based on increasing the cross-sectional area from the inlet to the outlet along the distance along the pumping channel, which in some embodiments is equal to the angle of rotation. This allows power consumption to be improved while providing the required volumetric compression of the gas. Some example embodiments are presented in the following sections.

FIG. 1 shows a pump in the form of a helical screw stator, wherein an increase in the cross-sectional area of the pumping channel is provided by an increase in the radial distance between the stator 20 and the rotor 10 from the inlet 52 to the outlet 54 . Having a tapered stator form as in this embodiment provides an increased cross-sectional area, however, there is an increased distance between the rotor and stator and to compensate for this, the exit velocity of the liquid (in this embodiment, thickness of water or water flakes) must be increased. In this embodiment, the thickness of the water sheet is increased by providing a slit 12 of increased width through which the water exits toward the outlet 54 side of the pump. This is more energy efficient than an increase in the speed at which the water leaves. However, there is still a power loss associated with the increased water forming the water vanes.

In other embodiments, the rotor may be tapered like the stator, and an increase in the diameter of the rotor towards the outlet results in an increase in the exit velocity of the water exiting the slot 12 . The angle of the rotor taper may be smaller than the angle of the stator taper, resulting in an increase in the distance between them and a corresponding increase in one of their cross-sectional areas towards the outlet. Increasing the diameter of the rotor is an energy saving way to provide the desired increase in the exit velocity of the water towards the outlet.

Figure 2 shows a second and (in some cases) preferred embodiment in which the radial distance between rotor 10 and stator 20 is constant. The increase in the cross-sectional area of the pumping channel is provided by the change in pitch from the inlet 52 to the outlet 54 . This allows the slit 12 to have a constant width and provides a corresponding constant width water blade. This may be more energy efficient than the embodiment of FIG. 1 .

Although the embodiments in Figures 1 and 2 show straight water vanes, these embodiments are also applicable to helical water vanes that can be formed with helical slits. This can be used with a corresponding helical screw on the stator or with a stator that is not actually contoured. Furthermore, the pitch of the slits forming the water vanes can be varied to provide increased cross-sectional area of the pumping channel and/or the distance between rotor 10 and stator 20 can be varied to provide this increased cross-sectional area.

Figure 3 shows an alternative embodiment similar to a rotary vane pump. In this embodiment, rotor 10 is mounted within stator 20 and includes slits 12 through which liquid exits in operation to form liquid vanes. The pumping channel 38 is formed by the walls of the stator 20 and the gas is driven by the vanes from the inlet 52 to the outlet 54 as the rotor 10 rotates. The inlet 52 has a cross-sectional area that is smaller than the outlet 54 to accommodate the volume reduction that will occur due to the accumulation of liquid from the liquid vane within the channel as the water vane rotates. The floor of the pumping channel at the inlet is higher than the floor of the pumping channel at the outlet 54 so that during operation, any liquid that accumulates in the pumping channel will drain and exit at the outlet 54 with the gas. As can be seen, the cross-sectional area 38 of the pumping channel increases from the inlet 52 to the outlet 54 .

Figure 4 shows an overview of one path through the pumping channel from the inlet to the outlet. As can be seen, the path follows an almost circular path so that the rotational movement drives the gas in an efficient manner. Due to the drainage requirements, there is a slightly vertical aspect of the circular path, but this is small making this an efficient way to pump gas. The helical configuration has a large vertical component imparted to the gas, and this is not in the direction of the rotation and therefore the vanes, and therefore does not provide efficient pumping.

FIG. 5 shows a side view of the pump of FIGS. 3 and 4 . A pumping channel 38 is formed in the stator 20 or the stator 20 of the pump. Rotor 10 is rotatably mounted within stator 20 and includes one or more slits 12 that form a liquid vane to push gas along pumping channel 38 . The cross-sectional area of the pumping channel 30 increases from the inlet to the outlet, and the lower surface or floor of the pumping channel is at a position slightly lower than the inlet at the outlet. Furthermore, a sealing member 32 is provided to seal between the stator and the rotor. In this regard, for at least some circumferences of the stator closer to the inlet, the length of the slit 12 is longer than the length of the channel and thus to inhibit leakage of the liquid discharged from the slit 12 from the pump, a seal 32 is provided on either side of the pumping channel. an edge.

While illustrative embodiments of this invention have been disclosed in detail herein, with reference to the accompanying drawings, it is to be understood that this invention is not limited to the precise embodiments and that those skilled in the art can claim the scope of the invention as disclosed in the accompanying drawings and Various changes and modifications are implemented therein, provided that the scope of the invention is defined by their equivalents.

10: Rotor 12: Liquid opening 20: Stator 32: Sealing member 38: Pumping channel 52: Entrance 54: Export

Embodiments of the present invention will be further described with reference to the accompanying drawings, wherein: 1 shows a pump having a helical pumping channel according to one embodiment; Figure 2 shows an alternate embodiment of a helical path pump; 3 shows a liquid vane rotary vane pump according to an embodiment; Figure 4 shows an overview of a path through the pump of Figure 3; and FIG. 5 shows a further view of the pump of FIG. 3 .

10: Rotor

12: Liquid opening

20: Stator

52: Entrance

54: Export

Claims (18)

A pump for pumping a gas, the pump comprising: a rotor and a stator; At least one of the rotor or stator includes at least one liquid opening configured for fluid communication with a liquid source; The liquid opening is configured such that in response to a driving force, a flow of liquid is output from the opening, the flow of liquid forming a liquid vane between the rotor and the stator, limited by the stator, the rotor and the liquid vane. gas is driven through the pump along a pumping channel from a gas inlet toward a gas outlet in response to relative rotational motion of the rotor and the stator; wherein A cross-sectional area of the pumping channel is configured to increase from the gas inlet to the gas outlet. The pump of claim 1 wherein a distance between the rotor and the stator increases from the gas inlet to the gas outlet. The pump of any of the preceding claims, wherein the pump is configured such that during operation an amount of liquid output through the liquid opening increases from the gas inlet to the gas outlet. The pump of claim 3, wherein a cross-section of the liquid opening toward the gas outlet is greater than a cross-section toward the gas inlet. A pump as in any preceding claim, wherein the liquid opening forms a slit. The pump of claim 5, wherein the slit extends longitudinally parallel to an axis of rotation of the rotor. The pump of claim 5, wherein the slit is arranged in a helical form extending around a rotational axis of the rotor. The pump of claim 7, wherein an angle of the helix varies from the gas inlet toward the gas outlet such that a pitch of the helix increases toward the gas outlet. The pump of any of the preceding claims, wherein one of the rotor and the stator includes a helical protrusion extending toward the other element including the liquid opening and defining a helical path of the pumping channel. The pump of claim 9, wherein a pitch of the helical protrusion increases from the gas inlet to the gas outlet. The pump of any one of claims 1 to 5, wherein the stator and rotor are configured such that the pumping channel runs around a circumference of the rotor or an interior channel of the stator, the gas inlet is configured to be vertical in operation above the gas outlet. The pump of claim 11, the pump further comprising a sealing member between the side walls and the rotor or stator including the liquid opening. A pump as in claim 11 or 12, wherein a lower surface of the pumping channel at the gas outlet is lower than a lower surface of the pumping channel at the gas inlet, and one of the pumping channels at the gas outlet The upper surface is higher than a lower surface of the pumping channel at the gas inlet. The pump of any of the preceding claims, wherein a cross-sectional area of the pumping passage is determined by a radial length as a distance between the rotor and the stator and as a radial length perpendicular to the pump A dimension of the feed channel defines an axial width that increases from the gas inlet to the gas outlet. A pump as in any preceding claim, wherein the rotor includes the liquid opening and is mounted for rotation within the stator. The pump of any preceding claim, wherein a cross-sectional area of the pumping passage is defined by: a radial length, the radial length being a distance between the rotor and the stator; and a Axial width, which is a dimension of the pumping channel perpendicular to the radial length, the pump is configured such that the axial width of the pumping channel varies with radial distance from the liquid opening increase and decrease. The pump of any preceding claim, wherein the pump is configured such that the increase in cross-sectional area from the gas inlet to the gas outlet is based on a liquid supplied to the pump to form the liquid vane in normal operation The amount is selected such that a cross-sectional area of the pumping channel available for gas decreases from the gas inlet to the gas outlet, and the gas being pumped is compressed. The pump of any preceding claim, wherein the pump comprises a vacuum pump.

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