ES2832676T3 - Vacuum pump - Google Patents

Abstract

Vacuum pump (1) for lowering the pressure in a device (120), the vacuum pump (1) comprising a vacuum chamber (2) with a chamber wall (21); wherein the chamber wall (21) comprises a minor point (22), which is the point of the chamber wall (21) where the distance between the chamber wall (21) and the rotor (3) is minimum, and a maximum point, which is a point at which a first virtual-size palette (501) is located so that the volume enclosed by the first virtual-size palette (501) and a second virtual-size palette (502), preceding the first virtual size pallet (501), is maximum; a rotor (3) housed in the vacuum chamber (2), this rotor (3) comprising at least one slot (31); at least one vane (4, 41, 42), each vane (4, 41, 42) being at least partially inserted into a groove (31) of the rotor (3); at least one fluid inlet (5) that is located between a first entry point (51) of the chamber wall (21) and a second entry point (52) of the chamber wall (21), the first being fluid inlet (5) suitable to be in fluid communication with the device (120) in which it is intended to reduce the pressure; and a primary fluid outlet (61) that is located between a first primary outlet point (611) from the chamber wall (2) and a second primary outlet point (612) from the chamber wall (2), being the primary fluid outlet (61) in fluid communication with a first outer fluid zone (100) of the vacuum pump (1); a secondary fluid outlet (62) that is located between a first secondary outlet point (621) from the chamber wall (2) and a second secondary outlet point (622) from the chamber wall (2), the secondary fluid outlet (62) in fluid communication with a second outer fluid zone (100 ') of the vacuum pump (1), the distance between the first secondary outlet point (621) and the minor point (22) being less than the distance between the first primary outlet point (611) and the minor point (22); wherein a chamber wall volume defined by a first virtual exit vane (601) in contact with the first secondary exit point (621) and a second virtual exit vane (602) that is posterior to the first vane virtual outlet (601) is greater than a chamber wall volume defined by a third virtual outlet vane (603) in contact with the second primary outlet point (612) and a fourth virtual outlet vane (604) that precedes the third virtual output paddle (603); wherein the primary fluid outlet (61) comprises primary blocking means (71) adapted to seal fluid communication between the primary fluid outlet (61) and the first outer fluid zone (100) if the pressure in the primary fluid outlet (61) is less than a first predetermined value; and in which a compression zone (11) is defined in the vacuum chamber (2), the compression zone (11) being limited by a first virtual compression paddle (401) located in contact with a larger point (23 ); the highest point being the second entry point (52) or the maximum point; a second virtual compression paddle (402) located in contact with the minor point (22); a portion of the rotor (3) comprised between these two first (401) and second (402) virtual compression vanes, considered in the direction from the first virtual compression vane (401) to the second virtual compression vane (402); and a portion of the chamber wall between the major point (23) and the minor point (22), considered in the direction from the first virtual compression vane (401) to the second virtual compression vane (402) and where The fourth virtual outlet vane (604) is comprised within the compression zone (11).

Description

DESCRIPTION

Vacuum pump

Technical field

The present invention belongs to the field of vacuum pumps that comprise a rotor with one or more vanes inserted inside it, the rotor in turn being contained in a vacuum chamber, in which subspaces are created between the vane or vanes. and the chamber wall when the rotor is moved.

State of the art

Vacuum pumps generally comprise a pump chamber and a rotor housed within the pump chamber. This rotor comprises one or more grooves, so that a vane is inserted at least partially in each of said grooves. The pump chamber houses this rotor, but the internal volume of the pump chamber is greater than the volume occupied by the rotor and the vanes. Therefore, when the rotor rotates, the vane or vanes have some room to exit the rotor due to centrifugal force or any other force provided on the pump. But this internal volume of the vacuum chamber is designed in such a way that the vanes enter and exit the rotor alternately, in such a way that the chambers that are created between two consecutive vanes and the corresponding portion of the chamber wall have a variable volume. , depending on the position of the rotor. In the case of a single vane with a single slot, the slot allows the single vane to exit the rotor at two diametrically opposite locations, so that the vane divides the vacuum chamber into different chambers. A fluid inlet located in the chamber wall is in fluid connection with a device in which the pressure is intended to be reduced and feeds the vacuum chamber at an inlet point with a compressible fluid, such as air or any other gas. Since this entry point is fixed, but the vanes move with the rotor, this entry point feeds different chambers while the rotor rotates. A fluid outlet is in turn located at an outlet point on the chamber wall and is in fluid connection with an outer fluid zone, such as the atmosphere or a different device. When the pressure at this outlet point is higher than the pressure in the outer fluid zone, the fluid exits the chamber.

These pumps work relatively well when the pressure in the device in which it is intended to reduce the pressure is far from vacuum, but when the pressure in the device drops, the pressure at the fluid outlet point may be lower than the pressure in the fluid zone outside the chamber. Therefore, there is a risk that the fluid from the outer fluid zone enters the chamber through the outlet point of the fluid, increasing the pressure in the chamber that is in fluid connection with the outlet point, and thus penalizing the efficiency. of this pump. WO2015 / 104930A1 discloses a rotary vane type gas compressor comprising a primary and a secondary outlet.

Description of the invention

The invention provides a solution to this problem by means of a vacuum pump according to claim 1. Preferred embodiments of the invention are defined in the dependent claims.

In a first inventive aspect, the invention provides a vacuum pump for reducing pressure in a device, the vacuum pump comprising

a vacuum chamber with a chamber wall; where the chamber wall comprises a minor point, which is the point on the chamber wall where the distance between the chamber wall and the rotor is minimum and a maximum point, which is a point where it is placed a first virtual-size palette so that the volume enclosed by the first virtual-size palette, and a second virtual-size palette preceding the first virtual-size palette is maximum;

a rotor housed in the vacuum chamber, this rotor comprising at least one slot;

at least one blade, each blade being at least partially inserted into a slot in the rotor;

at least one fluid inlet that is located between a first chamber wall entry point and a second chamber wall entry point, the first fluid inlet being suitable to be in fluid communication with the device in which it is intended to reduce the pressure; Y

a primary fluid outlet that is located between a first primary outlet point of the chamber wall and a second primary outlet point of the chamber wall, the primary fluid outlet being in fluid communication with a first outer fluid zone of the vacuum pump;

a secondary fluid outlet that is located between a first secondary outlet point of the chamber wall and a second secondary outlet point of the chamber wall, the secondary fluid outlet being in fluid communication with a second outer fluid zone of the vacuum pump, the distance between the first secondary outlet point and the minor point being less than the distance between the first primary outlet point and the minor point;

wherein a chamber wall volume defined by a first virtual exit vane in contact with the first secondary exit point and a second virtual exit vane that is posterior to the first virtual exit vane is greater than the volume of the chamber wall defined by a third virtual exit vane in contact with the second primary exit point and a fourth virtual exit vane preceding the third virtual exit vane; wherein the chamber wall comprises a minor point, which is the point on the chamber wall where the distance between the chamber wall and the rotor is minimal;

wherein the primary fluid outlet comprises primary blocking means adapted to seal fluid communication between the primary fluid outlet and the first outer fluid zone if the pressure at the primary fluid outlet is less than a first predetermined value.

By way of definition and without limitation, a compression zone is defined in the vacuum chamber, the compression zone being limited by

a first virtual compression paddle located in contact with a major point; the largest point being the second entry point or a maximum point, in which a first virtual-size palette placed at the maximum point makes the volume enclosed by the first virtual-size palette, a second virtual-size palette that precedes the the first virtual-size vane and the portions of the chamber wall and rotor between these virtual-size vanes is maximum;

a second virtual compression paddle located in contact with the minor point;

a portion of the rotor comprised between these two first and second virtual compression vanes, considered in the direction from the first virtual compression vane to the second virtual compression vane; Y

a portion of the chamber wall between the major point and the minor point, considered in the direction from the first virtual compression vane to the second virtual compression vane.

According to the invention, the fourth virtual outlet vane is comprised within the compression zone. Throughout the document, the term "chamber wall" includes all surfaces that limit the vacuum chamber, not only its side walls, but also includes the cover or the base of the vacuum chamber.

The concepts of "before" and "after" must be understood in the direction of advance of the rotor. In this sense, the preceding pallet of a first pallet is the pallet that is most advanced in the forward direction with respect to said first pallet, the pallet that "sees" the points before this first pallet. The rear vane of a first vane is therefore the vane that is further retarded in the forward direction with respect to said first vane, the vane that "sees" the points later than this first vane.

In vacuum pumps that have a single vane that crosses the rotor and exits the rotor at two different points, the concepts of "precedent" and "back" refer to the halves of said vane: one half of the vane would be the front and the back paddle relative to the other half of the paddle.

In this pump, the primary and secondary fluid outlets are close enough that a first volume between two consecutive vanes is in fluid communication with the primary and secondary fluid outlets at the same time.

This vacuum pump has an improved efficiency with respect to those of the state of the art, since the presence of fluid outlets allows the fluid to exit during the first phase of operation of the pump, avoiding unnecessary compression of the fluid before its use. outlet through fluid outlet. During the second phase of operation of the pump, the first blocking means at the primary fluid outlet prevent the entry of air into the vacuum chamber and only the secondary fluid outlet allows the fluid to exit without reaching an overpressure. Furthermore, the distance between the primary and secondary fluid outlets means that, although if these blocking means are closed, a high pressure is not reached until the volume of fluid reaches the secondary fluid outlet.

In some particular embodiments, the primary fluid outlet and the secondary fluid outlet are located within the compression zone.

This contributes to efficient operation of the vacuum pump.

In some particular embodiments, the vacuum pump further comprises a final fluid outlet, which is located between a first final outlet point of the chamber wall and a second final outlet point of the chamber wall, in which

the distance between the first primary exit point and the minor point is greater than the distance between the first final exit point and the minor point;

the distance between the first final exit point and the minor point is less than the length of the portion of the chamber wall between the first virtual exit vane and the second virtual exit vane; Y

the first and second final outlet points are located in the compression zone of the vacuum chamber.

This final fluid outlet provides an escape path for fluid that is near the minor point.

In some particular embodiments, the final fluid outlet comprises a final blocking means, adapted to seal fluid communication between the final fluid outlet and a third outer fluid zone if the pressure at the final fluid outlet is less than a third default value.

This final blocking means provides an improvement in the efficiency of the vacuum pump.

In some particular embodiments, the secondary fluid outlet comprises a secondary blocking means adapted to seal fluid communication between the secondary fluid outlet and the second outer fluid zone if the pressure at the secondary fluid outlet is less than a second value. predetermined.

This secondary blocking means provides an improvement in the efficiency of the vacuum pump.

The first and / or the second and / or the third predetermined value can be a pressure value that can depend on the pressure in the corresponding outer fluid zone or a constant value.

In these embodiments, the first outlet is far enough away from the trough, still ensuring the main feature of allowing a first volume between two consecutive vanes to be in fluid communication with the primary and secondary fluid outlets at the same time. This helps to control the pressure in a larger portion of the vacuum chamber compared to where they are closer to the trough.

In some embodiments, the primary and / or secondary and / or final locking means comprise a one-way valve.

In some embodiments, the vacuum pump comprises more than one vane and in which the angle formed between two consecutive vanes is between 55 ° and 95 °.

In some embodiments, the vacuum pump comprises 4 or 5 or 6 vanes.

Although in some embodiments, the first, second and third exit fluid zones correspond to different zones (open atmosphere, another device, a channel that interconnects some other parts of the vehicle), in other embodiments, at least some of the zones outlet fluid are the same area.

Brief description of the drawings

To complete the description and in order to provide a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate an embodiment of the invention, which should not be construed as a restriction of the scope of the invention, but only as an example of how the invention can be carried out. The drawings comprise the following figures:

Figure 1 shows a vacuum pump according to the state of the art, in a first operating position. Figure 2 shows a vacuum pump according to the state of the art, in a second operating position.

Figure 3 shows a schematic representation of the vacuum pump according to the present invention. Figure 4 shows a compression zone in a vacuum pump according to the present invention. Figure 5 shows a vacuum pump according to the present invention in a first position during operation.

Figure 6 shows a vacuum pump according to the present invention in a second position during operation.

Figure 7 shows a vacuum pump according to the present invention in a third operating position.

Figure 8 is a comparative graph showing the torque required to operate the vacuum pump of the present invention and the vacuum pumps of the state of the art.

Detailed description of the invention

Throughout the description, it is considered that the vacuum pump operates with an ideal gas, without taking into account the thermal or fluid-dynamic phenomena or changes of state in this gas, for the sake of clarity in the explanation of the invention. Some simplifications have been made in this regard, without losing the main scope of the invention.

Figures 1 and 2 show a vacuum pump 101 according to the state of the art. This vacuum pump 101 is intended to reduce the pressure of the device 120 and comprises

a pump chamber 102 with a chamber wall 121;

a rotor 103 housed in the pump chamber 102, this rotor 103 comprising a plurality of grooves 131; a plurality of vanes 104, each vane 104 being at least partially inserted into a slot 131 of rotor 103;

a fluid inlet 105 that is located at an entry point of chamber wall 121; and a primary fluid outlet 161 that is located at a primary outlet point of chamber wall 121;

wherein the primary outlet point is intended to be in fluid communication with an outer fluid zone 100.

Figure 1 shows the vacuum pump 101 in a first position during operation. In this position, a fluid enters the pump chamber 102 through the fluid inlet 105 and is maintained in a first volume 110 defined by two consecutive vanes 104, the chamber wall 121 and a portion of the rotor 103. While the rotor rotates, the first volume 110 becomes smaller (and the fluid pressure increases), while the portion of the chamber wall 121 that is comprised between the two consecutive vanes 104 that limit the first volume 110 is closer to the rotor 103 when rotor 103 rotates.

Figure 2 shows the vacuum pump 101 in a second position during operation. In this position, the pressure of the fluid that is maintained in the first volume 110 has increased, while the first volume 110 has been reduced by the rotation of the rotor 103. In this second position, the first volume 110 reaches the primary outlet point , wherein the pump chamber 102 comprises the primary fluid outlet 161. This primary fluid outlet 161 is in fluid communication with an outer fluid zone 100. If the pressure of the fluid contained in the first volume 110 is greater than the pressure in the outer fluid zone 100, the fluid will flow out of the first volume 110 when the first volume 110 is brought into fluid communication with the outer fluid zone 100, which is achieved by rotating the rotor 103, as shown in this second position.

But it can happen that the fluid enters the pump chamber 102 with a low pressure, and the pressure of the fluid upon reaching this second position is still lower than the pressure in the outer fluid zone 100. In this case, when the first volume 110 is brought into fluid communication with the outer fluid zone 100, the fluid from the outer fluid zone 100, with higher pressure, will enter the first volume 110. This will impair the efficiency of the vacuum pump 101.

Figure 3 shows a vacuum pump 1 according to the invention. This vacuum pump 1 comprises

a pump chamber 2 with a chamber wall 21;

a rotor 3 housed in the pump chamber 2, this rotor 3 comprises a plurality of grooves 31;

a plurality of vanes 4, each vane 4 being at least partially inserted into a groove 31 of the rotor 3;

a fluid inlet 5 that is located between a first entry point 51 of chamber wall 21 and a second entry point 52 of chamber wall 21, the fluid inlet 5 being in fluid communication with a device 120, in the one that is intended to reduce the pressure; Y

a primary fluid outlet 61 that is located between a first primary outlet point 611 from chamber wall 21 and a second primary outlet point 612 from chamber wall 21; the primary fluid outlet 61 being adapted to be in fluid communication with a first outer fluid zone 100;

a secondary fluid outlet 62 that is located between a first secondary outlet point 621 from chamber wall 21 and a second primary outlet point 622 from chamber wall 21; the secondary fluid outlet 62 being adapted to be in fluid communication with a second outer fluid zone 100 ';

wherein the primary fluid outlet 61 comprises primary locking means 71 that only allow fluid communication between the primary fluid outlet 61 and the first outer fluid zone 100 if the pressure at the primary fluid outlet 61 is equal to or greater to a first predetermined value that depends on the pressure in the first outer fluid zone 100.

The distance between the first secondary exit point 621 and the minor point 22 is less than the distance between the first primary exit point 611 and the minor point 22.

A volume of the chamber wall defined by a first virtual exit vane 601 in contact with the first secondary exit point 621 and a second virtual exit vane 602 that is posterior to the first virtual exit vane 601 is greater than the volume of the chamber wall defined by a third virtual exit vane 603 in contact with the second primary exit point 612 and a fourth virtual exit vane 604 preceding the third virtual exit vane 603. This means that, when moving from a first point at which fluid communication ceases with the primary fluid outlet to a second point at which fluid communication begins with the secondary fluid outlet, the volume at the second point is greater than the volume at the first point. In the embodiments shown in Figures 4-7, the volume is brought into fluid communication with the secondary fluid outlet even before fluid communication with the primary fluid outlet ceases.

In some particular embodiments, any of the first, second or third predetermined value is the result of the sum of two terms: an opening pressure and the pressure in the corresponding outer fluid zone. The opening pressure is a value that can be positive or negative, but, in absolute value, it is usually much lower than the pressure in the corresponding external fluid zone. The end result is that the corresponding locking means they remain sealed until the pressure at the corresponding fluid outlet is greater than this sum: the opening pressure (positive or negative) plus the pressure in the corresponding outer fluid zone. Consequently, if the opening pressure is negative, fluid communication is allowed even if the pressure at the corresponding fluid outlet is slightly lower than the pressure in the corresponding outer fluid zone. The corresponding locking means remains open until the pressure at the corresponding fluid outlet drops below this predetermined value.

A compression zone 11, as shown in figure 4, is defined in the vacuum chamber 2. This compression zone 11 is limited by

a first virtual compression paddle 401 located in contact with a major point 23, which is explained below;

a second virtual compression paddle 402 located in contact with the minor point 22;

a portion of the rotor 3 comprised between these two first and second virtual compression vanes 401 and 402, considered in the direction from the first virtual compression vane 401 to the second virtual compression vane 402; Y

a portion of the chamber wall between the major point 23 and the minor point 22, considered in the direction from the first virtual compression vane 401 to the second virtual compression vane 402.

Regarding the major point 23, depending on the arrangement of the pump, the major point may be the second entry point 52 or a maximum point. The maximum point of the pump is defined as the point at which when a first paddle of virtual size 501 is placed at the maximum point, the volume enclosed by the first paddle of virtual size 501, a second paddle of virtual size 502 preceding to the first virtual size vane 501 and the chamber wall and rotor portions between these virtual size vanes 501, 502, is maximum. In the case of Figure 4, the maximum point coincides with the second entry point 52, so the highest point also coincides with the second entry point 52.

The smallest point 22 is the point on the chamber wall 21 with the minimum distance to the rotor 3. The direction of advance of the vanes is the direction in which the rotor moves when the vacuum pump is in operation, therefore It is the direction in which the vanes advance when the vacuum pump is in operation.

The vanes of the vacuum pump have a position where the volume between two particular consecutive vanes is maximum. This maximum volume is achieved when a pallet is located at a first maximum point of the chamber wall and the preceding pallet is located at a second maximum point of the chamber wall.

If the second entry point 52 is located closer to the first primary exit point 611 in the direction of advance of the blades than this first maximum point, the major point 23 is the second entry point 52. But if the second entry point Entrance 52 is located further from the first primary exit point 611 in the direction of advance of the blades than this first maximum point, the major point 23 being the first maximum point. This depends only on the configuration of the vacuum pump and the position of the fluid inlet with respect to the vanes, so this point is always the same for each given vacuum pump, without depending on the operation.

In some embodiments, the chamber wall 21 may comprise more than one minor point 22 and more than one major point 23, because the rotor may be tangent to the chamber wall at more than one point (for example, in the case of a elliptical vacuum chamber). In these cases, the vacuum pump comprises more than one compression zone.

Primary fluid outlet 61 is located in compression zone 11.

This vacuum pump also comprises a secondary fluid outlet 62 and a final fluid outlet 63, all of them located in the compression zone 11 of the vacuum pump 1.

Figure 5 shows the vacuum pump 1 in a first position during operation. In this position, a fluid enters the vacuum chamber 2 through the fluid inlet 5, and is held in a first volume 10 defined by a front vane 41, a rear vane 42 and a portion of the chamber wall 21 as well as a portion of the rotor 3 comprised between these blades 41,42. As the rotor 3 rotates, after the rear vane 42 has reached the first maximum point, the first volume 10 becomes smaller, while the portion of the chamber wall 21 that is comprised between the two vanes 41, 42, limiting the first volume 10 is closer to the rotor 3 when the rotor 3 rotates.

The secondary fluid outlet 62 is located between a first secondary outlet point 621 of the chamber wall 21 and a second secondary outlet point 622 of the chamber wall, and the final fluid outlet 63 is located between a first point of end exit 631 from chamber wall 21 and a second end exit point 632 from chamber wall 21. The distance between the first secondary exit point 621 and the minor point 22 is greater than the distance between the first exit point end 631 and the minor point 22 but less than the distance between the first primary outlet point 611 and the minor point 22. As a consequence, during normal operation, the fluid entering the chamber Vacuum 2 first encounters the primary fluid outlet 61, then the secondary fluid outlet 62, and finally the final fluid outlet 63. The distance between the first final outlet point 631 and the minor point 22 is less than the portion of the chamber wall between the first virtual exit pallet 601 and the second virtual exit pallet 602.

The secondary fluid outlet 62 comprises a secondary blocking means 72 that only allows fluid communication between the secondary fluid outlet 62 and a second outer fluid zone 100 'if the pressure at the secondary fluid outlet 62 is equal to or greater than a second predetermined value that depends on the pressure in the second outer fluid zone 100 '.

The final fluid outlet 63 comprises a secondary blocking means 73 which only allows fluid communication between the final fluid outlet 63 and a third outer fluid zone 100 '' if the pressure at the final fluid outlet 63 is equal to or greater to a third predetermined value that depends on the pressure in the third outer fluid zone 100 ''.

In particular embodiments, the blocking means are check valves, which are designed to prevent fluid from flowing through them in one direction if the fluid pressure value does not reach a predetermined value.

Figure 6 shows the vacuum pump 1 in a second position during operation. In this position, the pressure of the fluid that is maintained in the first volume 10 has increased, while the dimensions of the first volume 10 have been reduced by the rotation of the rotor 3. In this second position, the first volume 10 reaches the first point primary outlet 611, thus entering into fluid communication with the primary fluid outlet 61. This primary fluid outlet 61 is in fluid communication with the first outer fluid zone 100 by the interposition of the primary blocking means 71, which only allows fluid communication between the primary fluid outlet 61 and the first outer fluid zone 100 if the pressure at the primary fluid outlet 61 is equal to or greater than a first predetermined value that depends on the pressure in the first outer fluid zone 100 Since the first volume 10 is in fluid communication with the primary fluid outlet 61, the pressure in the first volume 10 and the pressure in the primary fluid outlet 61 are the same. to.

If the pressure of the fluid contained in the first volume 10 is greater than the first predetermined value, the primary blocking means 71 allows fluid communication between the primary fluid outlet 61 and the first outer fluid zone 100. If the pressure of the fluid contained in the first volume 10 is furthermore higher than the pressure in the first outer fluid zone 100, the fluid exits the first volume 10 towards the first outer fluid zone 100. Since the advancement of the rotor leads to a decrease in the dimensions of the first volume 10, the pressure in this first volume 10 continues to increase and the fluid continues to flow out. But at the same time, the fluid exits the first volume 10 through the primary fluid outlet 61, therefore, the pressure in this first volume 10 decreases to the pressure of the first outer fluid zone 100 or until the primary blocking means 71 is activated. At some point, the rotation of the rotor 3 causes the first volume 10 to cease to be in fluid communication with the primary fluid outlet 61, when the rear vane 42 of the first volume 10 reaches the second primary outlet point 612.

When the vacuum pump 1 begins its operation and the pressure at the fluid inlet 5 remains relatively high, it is easy for the pressure in the first volume 10 to be high enough to open the first locking means 71. But as As the pressure at the fluid inlet 5 decreases, due to the operation of the pump, it is more difficult for the pressure in the first volume 10 to reach the first predetermined value required to open the locking means 71, and there is a point at the operation in which the first volume 10 comes into fluid contact with the first fluid outlet 61 and the fluid in the first volume has not reached sufficient pressure to open the first locking means 71. In this case, when the first volume 10 is brought into fluid communication with the primary fluid outlet 61, the fluid does not come out of the vacuum chamber 2, but neither does fluid enter the vacuum chamber 2, due to the primary blocking means 71, which prevents the communication of fluid between the primary fluid outlet 61 and the first outer fluid zone 100 if the pressure at the primary fluid outlet 61 is less than a first predetermined value. As the rotor 3 continues to rotate, the pressure in the first volume 10 continues to increase, without decreasing due to the leakage of fluid, since the primary blocking means 71 remains sealed until the pressure in the first volume 10 reaches the first default value. In fact, if this pressure increase causes the pressure in the first volume 10 to be equal to or greater than the first predetermined value while the first volume 10 is still in fluid contact with the first fluid outlet 61, the blocking means 71 is will open and fluid will begin to flow out. If not, the primary locking means 71 will remain sealed.

In some embodiments, such as those shown in these Figures 5 and 6, the distance between the tips of two consecutive blades is greater than the distance between a second outlet point and the first outlet point of the next fluid outlet. As a consequence, it is possible for the first volume 10 that the position of the front vane 41 causes the first volume to enter into fluid communication with a fluid outlet while the position of the rear vane 42 maintains the first volume in fluid communication with the front fluid outlet, as shown in Figure 7. In this position, the front vane 41 of the first volume 10 has passed the first secondary outlet point 621, while the rear vane 42 of the first volume 10 has not reached the second primary outlet point 612. Thus, the first volume 10 is in fluid communication with both the first fluid outlet 61 and the second fluid outlet 62.

In these embodiments, when the pressure in the first volume 10 is not high enough to open the first locking means 71 before the front vane 41 reaches the first secondary exit point 621, the first volume 10 will enter into fluid communication with the second fluid outlet 62 with a pressure that is not sufficient to open the first blocking means 71. If the second predetermined value is the same as the first predetermined value, the secondary blocking means 72 will also close, because the pressure in the first volume 10 is not sufficient to open the secondary locking means 72. But if the compression of the first volume 10 causes the pressure within this first volume 10 to be equal to or greater than the first and second predetermined values while the first volume 10 is still in fluid communication with the first fluid outlet 61, both the primary and secondary locking means will open. If this does not happen, both the first 71 and the second 72 locking means will be closed for as long as they are, at the same time, in fluid communication with the first volume. But as the rear flap 42 advances past the second primary exit point 612, the first volume 10 is further compressed, and it is possible that the secondary locking means 72 may open, due to the increased pressure in the first volume 10. .

The operation will continue, progressively reducing the pressure in the inlet 5 and, consequently, in the first volume 10, until a steady state flow is reached in the vacuum pump.

As a consequence, a vacuum pump of this type will be able to operate more efficiently, without wasting energy unnecessarily in the compression of the fluid and, collaterally, its operation will not be impaired by the entry of fluid into the vacuum pump through the points output.

A graph is illustrated in Figure 8 to show the difference between the average torque required to operate the rotor of three different vacuum pumps throughout its performance curve. The dashed line shows the torque required to drive the vacuum pump as is known in the state of the art having a single small outlet. The dotted line shows the torque required to drive the vacuum pump as known in the state of the art having a single large outlet. The solid line shows the torque required to drive the vacuum pump of the invention. The "small" outlet and the "large" outlet refer to the size of the single outlet, the second point of which is located near the smallest point of the vacuum pump (the second point and the smallest point must be understood according to the terminology used in the description of the vacuum pump of the invention). In the particular example of small outlet, the outlet extends approximately 18 degrees in the vacuum chamber and in the particular example of large outlet, the outlet extends approximately 73 degrees in the vacuum chamber.

Vacuum pumps with short outputs require more torque when starting a full operation, because the pressure reaches higher values and a higher compression rate is achieved. When, with the progressive operation of the pump, the pressure level decreases, the pressure difference between two consecutive chambers is smaller and, therefore, this pump becomes more efficient in terms of torque.

Vacuum pumps with a large output initially require less torque, since the large output does not allow the fluid to reach a high pressure. However, this lack of initial precompression in the chamber before communicating with the outlet leads to an increase in the pressure difference between the chamber open to the outlet fluid zones and the previous one, which generates a greater torque resistant to the throughout the operation of the pump.

With the vacuum pump according to the invention, a low torque is needed when starting operation and a low torque is needed in the second performance phase, as well as in the steady state.

In this text, the term "comprises" and its derivatives (such as "comprising", etc.) should not be understood in an exclusive sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include additional elements, additional stages, etc.

The present invention, obviously, is not limited to the specific embodiments described herein, but also encompasses any variation to be considered by any person skilled in the art (for example, regarding the choice of materials, dimensions, components, configuration , etc.), within the general scope of the invention as defined in the claims.

Claims (8)

1. Vacuum pump (1) to lower the pressure in a device (120), comprising the vacuum pump (1) a vacuum chamber (2) with a chamber wall (21); wherein the chamber wall (21) comprises a minor point (22), which is the point of the chamber wall (21) where the distance between the chamber wall (21) and the rotor (3) is minimum, and a maximum point, which is a point at which a first virtual-size palette (501) is located so that the volume enclosed by the first virtual-size palette (501) and a second virtual-size palette (502), preceding the first virtual size pallet (501), is maximum; a rotor (3) housed in the vacuum chamber (2), this rotor (3) comprising at least one slot (31); at least one vane (4, 41,42), each vane (4, 41, 42) being at least partially inserted in a groove (31) of the rotor (3); at least one fluid inlet (5) that is located between a first entry point (51) of the chamber wall (21) and a second entry point (52) of the chamber wall (21), the first being fluid inlet (5) suitable to be in fluid communication with the device (120) in which it is intended to reduce the pressure; and a primary fluid outlet (61) that is located between a first primary outlet point (611) from the chamber wall (2) and a second primary outlet point (612) from the chamber wall (2), being the primary fluid outlet (61) in fluid communication with a first outer fluid zone (100) of the vacuum pump (1); a secondary fluid outlet (62) which is located between a first secondary outlet point (621) from the chamber wall (2) and a second secondary outlet point (622) from the chamber wall (2), the secondary fluid outlet ( 62 ^{) in fluid communication with a second outer fluid zone (100 ') of the vacuum pump (1),} the distance between the first secondary outlet point (621) and the minor point (22) being less than the distance between the first primary outlet point (611) and the minor point (22); wherein a chamber wall volume defined by a first virtual exit vane (601) in contact with the first secondary exit point (621) and a second virtual exit vane (602) that is posterior to the first vane virtual outlet (601) is greater than a chamber wall volume defined by a third virtual outlet vane (603) in contact with the second primary outlet point (612) and a fourth virtual outlet vane (604) that precedes the third virtual output paddle (603); wherein the primary fluid outlet (61) comprises primary blocking means (71) adapted to seal fluid communication between the primary fluid outlet (61) and the first outer fluid zone (100) if the pressure in the primary fluid outlet (61) is less than a first predetermined value; Y in which a compression zone (11) is defined in the vacuum chamber (2), the compression zone (11) being limited by a first virtual compression paddle (401) located in contact with a major point (23); the highest point being the second entry point (52) or the maximum point; a second virtual compression paddle (402) located in contact with the minor point (22); a portion of the rotor (3) comprised between these two first (401) and second (402) virtual compression vanes, considered in the direction from the first virtual compression vane (401) to the second virtual compression vane (402); Y a portion of the chamber wall between the major point (23) and the minor point (22), considered in the direction from the first virtual compression vane (401) to the second virtual compression vane (402) and where the Fourth virtual exit paddle (604) is comprised within the compression zone (11). 2. Vacuum pump (1) according to claim 1, wherein the primary fluid outlet (61) and the secondary fluid outlet (62) are located within the compression zone (11). Vacuum pump (1) according to any of claims 1 or 2, further comprising a final fluid outlet (63), which is located between a first final outlet point (631) of the chamber wall ( 21) and a second final exit point (632) from the chamber wall (21), where the distance between the first primary exit point (611) and the minor point (22) is greater than the distance between the first final exit point (631) and the minor point (22); the distance between the first final exit point (631) and the minor point (22) is less than the length of the part of the chamber wall (21) between the first virtual exit vane (601) and the second vane of virtual output (602); Y The first (631) and the second (632) final outlet points are located in the compression zone (11) of the vacuum chamber (2). 4. Vacuum pump (1) according to claim 3, wherein the final fluid outlet (63) comprises a final blocking means (73), adapted to seal fluid communication between the final fluid outlet (63 ) and a third outer fluid zone (100 '') if the pressure at the final fluid outlet (63) is less than a third predetermined value. Vacuum pump (1) according to any of the preceding claims, wherein the secondary fluid outlet (62) comprises a secondary blocking means (72) adapted to seal fluid communication between the secondary fluid outlet ( 62) and the second outer fluid zone (100 ') if the pressure at the secondary fluid outlet (62) is less than a second predetermined value. 6. Vacuum pump (1) according to any of the preceding claims, in which the primary and / or secondary and / or final blocking means comprise a one-way valve. Vacuum pump (1) according to any of the preceding claims, comprising more than one vane and in which the angle formed between two consecutive vanes is between 55 ° and 95 °. 8. Vacuum pump (1) according to any of the preceding claims, comprising 4 or 5 or 6 vanes.