Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C25/00—Adaptations of pumps for special use of pumps for elastic fluids
  • F04C25/02—Adaptations of pumps for special use of pumps for elastic fluids for producing high vacuum
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2230/00—Manufacture
  • F04C2230/60—Assembly methods
  • F04C2230/602—Gap; Clearance

Definitions

• This invention belongs to the field of pumps comprising a rotor with one or more vanes inserted in it, the rotor being in turn contained in a housing, where subspaces are created between the vane or vanes and the housing wall and the rotor when the rotor is moved.
• pumps either a vacuum pump for magnifying the effect of a force or any other type of pump.
• These pumps usually comprise a housing and a rotor housed inside the housing.
• This rotor comprises one or more slots, so that a vane is at least partially introduced in each one of said slots.
• the housing houses this rotor, but the inner volume of the housing is greater than the volume occupied by the rotor and the vanes.
• the vanes have some space to exit the rotor due to centrifugal force or any other force provided in the pump.
• This inner volume of the housing is designed such that the vane or vanes go in and out the rotor alternatively, in such a way that the subchambers which are created between two consecutive vanes and the corresponding portion of the housing wall and the rotor have a variable volume, depending on the position of the rotor.
• the slot allows the single vane exiting the rotor in two diametrically opposed locations, so that the vane divides the main chamber in different subchambers.
• the invention provides a solution for this problem by means of a method for manufacturing and assembling a pump according to claim 1 and a vacuum pump according to claim 13.
• Preferred embodiments of the invention are defined in dependent claims.
• the invention provides a method for manufacturing and assembling a pump. This method comprises the steps of
• the rotor To make adequate use of the whole inner volume of the housing, the rotor must be placed eccentrically with respect to the housing, and this eccentricity must be carefully chosen to achieve a maximum ratio between the maximum subchamber volume and the minimum subchamber volume. Theoretically, this eccentricity is determined by the tangency contact between the rotor and the housing in one point, which will be called tangency point. In other words, the eccentricity distance is, theoretically, the housing radius minus the rotor radius. However, in the real assembly, to assume a real tangency implies a physical contact between a part which is rotating, potentially at high speed, and a static component.
• This method manufactures a pump with a controlled gap between the rotor and the housing, making this pump able to effectively select this gap distance regardless dimensional and geometrical tolerances affecting the parts comprised in this pump. Different parameters, such as pump speed, lubrication effect or performance values may be used to calculate an optimum distance, which may depend on the customers choices. This method allows the customer and/or pump manufacturer to obtain a determined gap distance in an easy and reliable way.
• the tangency direction turns out to be a direction which joins the point of the rotor which is closer to the housing and the point of the housing which is closer to the rotor, when the rotor is located in its operation position.
• the tangency direction is perpendicular to the common tangent line.
• this tangency direction is the direction joining the centre of the housing and the centre of the rotor.
• both centres define a direction, which is the tangency direction. In other cases, when the housing is not circular, this direction also contains the centre of the rotor.
• the step of varying the distance between the housing and the rotor axis comprises
• the step of varying the distance between the housing and the rotor axis comprises
• the width of the intermediate element being substantially equal to the optimal distance
• the method further comprises the step of providing sensing means which are suitable for measuring the relative position between the rotor or the rotor mock-up and the housing.
• sensing means are useful during the steps of reducing and/or increasing the distance between the housing and the rotor. Some sensors may be used to detect the moment where housing and rotor make contact, thus avoiding hitting the rotor with an uncontrolled force, and some different sensors may be used to check that the housing reaches the optimal distance, thus obtaining a final positioning of the housing in a reliable way.
• the step of varying the distance between the housing and the rotor axis is carried out by displacing the housing with respect to the rotor axis.
• Housing is usually easier to displace than the rotor, which usually needs to be displaced together with the electric motor and other parts.
• the housing comprises handling means, such as a tab, a flange or a handle.
• the housing being open allows a better control for the operation of varying the distance between the rotor and the housing.
• the step of varying the distance between the housing and the rotor axis is carried out with the housing being closed (either by a previous operation or by design, being a closed cover).
• the housing comprises an opening
• the method further comprises the step of closing the opening after varying the distance between the housing and the rotor axis.
• This opening allows the operator or any artificial vision device to visually control the operations of reducing and/or increasing the distance, which makes visual control easier in the event this process is not easily seen from an upper position.
• this opening allows the adjustment of the distance by using a measurement sensor or any other device through itself. The opening must be closed afterwards, for the housing to be gastight.
• the step of varying the distance between the housing and the rotor axis is carried out with the aid of some guiding means, such as pins and slots.
• Guiding means help the relative movement occur according to the tangency direction.
• the guiding means are slots; these slots must be therefore oriented in the tangency direction.
• the step of affixing the relative position between the housing and the rotor axis is by means of attaching means such as screws, clamps, rivets or adhesive joint.
• the step of affixing the relative position between the housing and the rotor axis is made by reversible fixation means, which may be removed during the pump lifetime and rearranged after maintenance operations.
• Reversible fixation means provide the opportunity of being able to recalibrate the distance between the rotor and the housing in the event that operation may misadjust the position of these elements.
• the method further comprises the step of making the rotor or the rotor mock-up rotate with respect to the rotor axis while the step of varying the distance between the housing and the rotor axis is being executed.
• the fact of making the rotor rotate saves the influence of some additional tolerances in this process.
• the invention provides a vacuum pump manufactured by a method according to any of the preceding claims, the vacuum pump comprising
• a rotor at least partially housed in the housing
• a rotor axis the rotor being arranged to rotate around the rotor axis
• This pump may be advantageously manufactured and assembled with less restrictive requirements for dimensional and geometrical tolerances, since the distance between the rotor and the housing may be adjusted independently.
• the vacuum pump further comprises handling means, such as a tab, a flange or a handle.
• the means for affixing the distance between the housing and the rotor axis are attaching means, such as screws, clamps, rivets or adhesive joint.
• the means for affixing the distance between the housing and the rotor axis are reversible fixation means, which may be removed during the assembly process or the pump lifetime and rearranged after maintenance operations.
• Figures 1 a to 1 d show three different steps of a first embodiment of a method for manufacturing and assembling a pump according to the invention.
• Figure 2 shows a particular way of performing two steps of a method for manufacturing and assembling a pump according to the invention.
• Figure 3 shows a graphic with information regarding the relation between the distance between the housing and the rotor and the output pressure in a vacuum pump according to the invention.
• Figures 1 a to 1 d show three different steps of a first embodiment of a method for manufacturing and assembling a pump 1 according to the invention.
• Figure 1 a shows the provision of a housing 2 and a rotor 3 placed on a rotor axis 31. In different calculations, an optimal distance g_opt between the housing 2 and the rotor 3 has been determined.
• FIG. 1 b shows the next step of this method.
• This step comprises reducing the distance between the housing 2 and the rotor axis 31 in a tangency direction d, until the housing 2 and the rotor 3 make contact.
• sensing means are provided. These sensing means are suitable for measuring the relative position between the rotor and the housing. Although the distance is reduced until the housing 2 and the rotor 3 make contact, this should be made in a careful way, not to cause damage in any of these elements.
• an intermediate element is located between the housing and the rotor.
• the width of the intermediate element is substantially equal to the optimal distance.
• the housing 2 which is displaced towards the rotor axis 31 , but in other embodiments, it is the rotor axis 31 which may be displaced towards the housing 2.
• the displacement of the housing 2 may be performed with the aid of some handling means, such as a tab, a flange or a handle.
• a calibrated machine may make use of these handling means for a more controlled movement of the housing 2.
• Figure 1 c shows a further step of this method.
• This step comprises increasing the distance between the housing 2 and the rotor axis 31 in a tangency direction d, until the distance between the housing 2 and the rotor 3 is substantially equal to the optimal distance g_opt.
• the target relative position between the housing 2 and the rotor 3 can be achieved during the assembly process by the sensing means.
• these sensing means comprise known elements to control the distance between two points.
• Some sensing means which could be used are: a stroke sensor, a travel transducer, force sensors, vision sensors, gauges, calibrated parts, any combination of them or any equipment or procedure which may allow the control of the required value for this distance between the housing 2 and the rotor 3.
• Different sensing means may be used during the steps of reducing and increasing the distance between the housing 2 and the rotor 3.
• Some sensors may be used to detect the moment where housing 2 and rotor 3 make contact, and some different sensors may be used to check that the housing 2 reaches the optimal distance g_opt.
• slots 51 and pins 52 are provided in the housing 2 or in a piece which is solidly attached to the housing, and the other being comprised in the base of the rotor 32 or in a piece which is solidly attached to the base of the rotor, just for setting a position reference.
• the slots 51 are comprised in a housing support 21 , which is part of the housing 2 and the pins 52 are solidly attached to the base of the rotor 32.
• the slots are oriented in the tangency direction d, in such a way that when pins 52 move within the slots 51 , the rotor 3 displaces relatively to the housing 2. and the distance between the rotor 3 and the housing 2 is therefore adjusted.
• handling means 4 such as a tab, a flange or a handle or some similar element, located in the housing 2.
• This step comprises affixing the relative position between the housing 2 and the rotor axis 3.
• the step of affixing the relative position between the housing 2 and the rotor axis 31 will be performed by means of attaching means such as screws, clamps, rivets or adhesive joint, although this step is not illustrated by the figures. Welding or crimpling may also be used for this purpose. A final attachment is therefore achieved, so that the pump works its entire lifetime with the same settings.
• this step of affixing the relative position between the housing and the rotor axis is made by reversible fixation means, which may be removed during the pump lifetime and rearranged after maintenance operations.
• Figure 2 shows a particular way of performing the steps of reducing and increasing the distance between the housing and the rotor axis.
• This figure 2 shows a housing 2 with an opening 22, so that the steps of reducing and increasing the distance between the housing and the rotor axis may be visually controlled by this opening 22, either by an operator or by any artificial vision device, or even using sensing means through the opening. This opening must be closed afterwards, so that the final housing 2 is gastight.
• Figure 3 shows the influence of this distance between the housing and the rotor (called in this graphic "g") in the operation of a vacuum pump.
• Five different values for this distance g have been used and, as discussed before, the lower this gap in the pump, the lower the absolute pressure in the output of this vacuum pump and the quicker the vacuum generation.
• the rotor is circular, with a diameter of 38 mm
• the housing is also circular, with a diameter of 48 mm.
• the optimal distance g_opt taking into account other considerations, such as required power and efficiency, should be set preferably between 0.05 and 0.25 mm.
• the optimal distance g_opt between the rotor and the housing is set, apart from the measurements of the sensing devices, from the specific product requirements (maximum vacuum level, required efficiency) and physical features of the vacuum pump (position of inlet and outlet ports or other design features).
• the term “comprises” and its derivations (such as “comprising”, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Applications Or Details Of Rotary Compressors (AREA)
• Non-Positive Displacement Air Blowers (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=58094361

Family Applications (1)

Country Status (4)

Citations (4)

Family Cites Families (4)

• 2017
  • 2017-02-10 EP EP17382068.9A patent/EP3361099A1/de not_active Withdrawn
• 2018
  • 2018-01-26 CN CN201880000773.6A patent/CN108884833A/zh active Pending
  • 2018-01-26 ES ES18701490T patent/ES2987497T3/es active Active
  • 2018-01-26 EP EP18701490.7A patent/EP3580459B1/de active Active
  • 2018-01-26 WO PCT/EP2018/051985 patent/WO2018145925A1/en not_active Ceased

Patent Citations (4)

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