Vent valves and vacuum pumps equipped with such vent valves
Patent Information
- Application Number
- JP2024192688
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2023-12-15
- Filing Date
- 2024-11-01
- Publication Date
- 2026-09-18
- Estimated Expiration
- 2044-11-01
Smart Images
Figure 0007923804000001 
Figure 0007923804000002 
Figure 0007923804000003
Abstract
Description
[Technical Field]
[0001] The present invention relates to a ventilation valve capable of selectively opening and closing a ventilation opening formed in a housing of a vacuum pump, particularly a turbomolecular vacuum pump. The present invention further relates to a vacuum pump equipped with such a ventilation valve. [Background Art]
[0002] For example, vacuum pumps such as turbomolecular vacuum pumps often have a ventilation opening, through which pump stages present in the pump or the pump housing can be vented with air coming from the atmosphere. This makes it possible, for example, to accurately influence the rotational speed of the rotor of the pump stage.
[0003] In currently used vacuum pumps, the ventilation opening is usually closed by a simple ventilation screw. The ventilation screw can be manually loosened via a rotary drive in the form of a screw head, thereby opening the ventilation opening. Moreover, in this process, the ventilation screw is completely unscrewed from the ventilation opening, and in some cases there is a risk that it will fall into the facility of the pump operator. In the worst case, the ventilation screw can no longer be found, resulting in the facility being shut down until a new ventilation screw is provided.
[0004] Another problem is that the ventilation screw may tilt when screwed back into the ventilation opening, which in some cases may lead to damage to the thread of the ventilation opening. [Summary of the Invention] [Problem to be Solved by the Invention]
[0005] Therefore, the problem underlying the present invention is to provide a ventilation valve for a vacuum pump, particularly a turbomolecular vacuum pump, that takes the aforementioned problems into account. [Means for Solving the Problem]
[0006] This problem is solved by a vent valve for opening and closing the vent opening of a vacuum pump, particularly a turbomolecular vacuum pump, in which case the vent valve is superior in the features of claim 1.
[0007] Unlike conventional vent screws, this vent valve consists mainly of two components: a valve housing and a valve element. In this case, the valve element is inseparably housed by the valve housing, while the valve housing itself is configured to be housed in the vent opening of a vacuum pump. Specifically, a through-hole penetrates the valve housing. The through-hole connects two opposite end faces of the valve housing: a first axial end face and a second axial end face opposite the first axial end face. The valve element is a threaded body with male threads, and via these male threads, the valve element is screwed into female threads formed in the through-hole of the valve housing. Therefore, by rotating the valve element, its axial position relative to the valve housing can be changed.
[0008] Similar to conventional vent screws, the screw body also has a rotating drive mechanism at a first end, for example in the form of a screw head, which allows the valve element to be rotated manually, thereby changing the axial position of the valve element relative to the valve housing. On the other hand, at the other end, the screw body has a valve plate formed integrally with the screw body. The valve plate abuts, at least indirectly, against the second axial end face of the housing at the first axial position of the valve element, thereby tightly closing the through hole. In contrast, at the second axial position of the valve element, the valve plate is spaced apart from the second end face. Therefore, at the second axial position, the through hole is not closed by the valve plate, and based on the gap between the female threads of the through hole and the male threads of the screw body, air coming from the atmosphere can flow through the vent valve into the interior of the pump.
[0009] The valve plate is positioned within the vacuum pump, with the end of the valve plate opposite to the rotating drive mechanism of the screw shaft, and therefore incorporated into the vacuum pump's vent opening, so that the valve element does not accidentally detach from the valve housing and fall into the pump operator's equipment. Rather, if the valve element were to "detach," the valve plate would then contact the second axial end face of the valve housing at the first axial position of the valve element, which prevents the valve element from detaching further from the valve housing.
[0010] Preferred embodiments of the present invention will be described below. Other embodiments may be apparent from the dependent claims, the description of the drawings, and the drawings themselves.
[0011] Based on the thread play already described above, at the second axial position of the valve element, air coming from the atmosphere can flow into the vacuum pump through the through-hole of the valve housing, but a vent valve is fitted into the vent opening of the vacuum pump, and therefore, based purely on the thread play, the possible airflow for venting the vacuum pump is restricted. In another embodiment, an axial channel is formed in the thread body, aligned substantially axially or longitudinally, and the axial channel enables fluid connection through the thread body for venting the vacuum pump only at the second axial position, while the axial channel interrupts the airflow into the vacuum pump at the first axial position of the valve element.
[0012] The axial channel may be, for example, an axially extending groove that extends along the screw body on the outer circumference between the first end of the screw body and the valve plate. Thus, the groove in question intersects, to some extent, with the threads of the male screw of the screw body. When the valve element is in its first axial position, the valve plate abuts, at least indirectly, against the second axial end face of the valve housing, and therefore, based on the fact that the valve plate already seals the through hole, fluid flow through the axial channel in the form of an elongated surface groove is impossible. In contrast, in the second axial position of the valve element, incoming air from the periphery can flow into the pump through the axial channel to ventilate the pump, and in this case, the flow cross-section is not restricted by the threads.
[0013] Furthermore, the axial channel may be a hole formed inside the screw body, which extends from the first end of the screw body to the second end, where it exits the screw body adjacent to the valve plate. Therefore, in this embodiment, the axial channel extends slightly obliquely to the longitudinal axis of the screw body, thereby allowing the axial channel to exit the screw body laterally at the second end of the screw body.
[0014] In one preferred embodiment, the axial channel may be configured as a blind hole having an open end formed at a first end of the screw body and a closed end located at a second end of the screw body. In this embodiment, the axial channel may extend precisely parallel to the central axis of the screw body, preferably along the central axis. In this embodiment, in order to realize fluid flow through the axial channel, at least one radial hole may be further formed in the screw body, substantially radially oriented, preferably precisely radially, the radial hole branching off from the blind hole and exiting the screw body at the second end of the screw body or adjacent to the valve plate. Thus, at the second axial position of the valve element, incoming air from the atmosphere can flow through the blind hole and the radial hole branching off from the blind hole into the vacuum pump fitted with the vent valve. In other words, at the second axial position of the valve element, at least one radial hole opens at a distance from the second end face of the valve plate at the second axial position of the valve element, so that air arriving from the atmosphere can flow into the pump through this distance.
[0015] In order to realize multiple ventilation conditions with various volumetric flow rates, according to another embodiment, the screw casing is formed with a first radial hole oriented substantially radially and at least one second radial hole oriented substantially radially, in which case the first radial hole as a whole may be intended to be located closer to the valve plate than the second radial hole. Thus, the first radial hole exits the screw casing closer to the valve plate than the second radial hole.
[0016] Therefore, at the second axial position of the valve element, the first radial hole opens in the manner described above, to the distance the valve plate has with respect to the second end face of the valve housing at the second axial position of the valve element, where at this second axial position of the valve element, the opening of the second radial hole is still located in the threaded region of the female thread of the through hole in the valve housing, so there is no or only a small volumetric flow rate that can pass through the second radial hole. Thus, at the second axial position of the valve element, the inside of the pump is fluidly connected to the external atmosphere exclusively through the blind hole and the first radial hole branching from the blind hole. In contrast, in other ventilation conditions, a larger volumetric flow rate should be achieved, and therefore the valve element can be screwed further into the inside of the pump, so the opening of the second radial hole is also located in the distance between the valve plate and the second axial end face of the valve housing. Thus, at the third axial position of such a valve element, the external atmosphere is fluidly connected to the inside of the pump through the two radial channels. Therefore, assuming that the flow cross-section of the blind hole is not smaller than the smaller diameter of the two radial holes, a larger volumetric flow rate can be achieved at the third axial position of the valve element than at the second axial position of the valve element.
[0017] In order to accurately realize various fluid conditions in which the volumetric flow rate increases, according to another embodiment, the diameter of the second radial hole may be intended to be larger than the diameter of the first radial hole. In this case, since the diameter of the second radial hole is less than or equal to the diameter of the blind hole, at a third axial position where the two radial holes open in the gap between the valve plate and the second axial end face of the valve housing, the achievable volumetric flow rate through the two radial holes is greater than at a second axial position of the valve element where flow is essentially possible only through the first radial hole.
[0018] In another embodiment, the second end of the threaded body where the two radial holes are located is located inside the vacuum pump when assembled to the vacuum pump, and therefore it is not possible to tell from the outside whether the openings of the respective radial holes are already open or still closed by the valve housing. In this case, the vent valve has a locking mechanism which acts or may be intended to act between the valve housing and the valve shaft when the distance between the valve plate and the second axial end face of the valve housing reaches a predetermined size. In this case, the distance is sized such that, at this position, the first radial hole opens in the distance between the valve plate and the second axial end face of the valve housing and is therefore no longer closed by the valve housing. In this case, the locking mechanism may be formed inside the valve housing, for example, by a radially spring-biased ball. The ball is pressed against the male threads of the valve shaft by spring bias. In this case, a point-like recess in the form of a depression is formed in the region of the male thread of the valve shaft, and a ball engages with the recess when it reaches a predetermined spacing and, consequently, reaches the second axial position of the valve element. Therefore, when the second axial position of the valve element is reached, the operator receives tactile feedback that the valve element has reached the second axial position as the ball snaps into the recess.
[0019] Based on the fact that the valve plate abuts the second axial end face of the valve housing at the first axial position of the valve element, it can be ensured that no fluid flow can occur through the vent valve, and the through hole moves to the second axial end face of the valve housing via a conical recess, provided that the valve plate has a frustoconical portion formed complementary to the conical recess on the side facing the second axial end face, and this frustoconical portion is accommodated by the conical recess at the first axial position of the valve element and abuts against the conical recess, in particular, the valve element can be sealed to the valve housing. Therefore, when the valve element moves to its first axial position, the seal provided on the valve plate can be attracted to the circumferential gap of the cone between the conical recess and the frustoconical portion of the valve plate, thereby ensuring, in particular, that no undesirable flow can occur through the vent valve at the first axial position.
[0020] The seal already described above may, according to one preferred embodiment, be a ring seal supported on the radially outer side of the frustoconical portion on the side facing the second axial end face of the valve plate. The ring seal may preferably be a ring seal that is vulcanized in contact with a steel support ring concentric with the ring seal. Such a seal is also known as a Usit ring, in which case the steel support ring is used to prevent overloading of the elastic material constituting the ring seal.
[0021] In yet another embodiment, the screw body may be intended to have a circumferential ring groove at its second end, adjacent to the valve plate, having a groove depth that matches or is slightly greater than the thread height of the male threads of the screw body. In this case, the first radial hole opens into the ring groove referred to, and therefore the first radial hole may be formed in the first screw body directly adjacent to the valve plate, and possibly to its frustoconical portion, in which case the male threads of the screw body do not need to extend to the valve plate. Thus, the portion of the screw body having the radial hole may be housed in a through hole of the valve housing, in which case it does not collide with the threads of the through hole.
[0022] To allow for intuitive operation of the vent valve, according to another embodiment, the male threads of the screw body and the female threads of the valve housing may be configured as left-hand threads. In contrast, if the threads are configured as right-hand threads, the valve element must be rotated clockwise to open the vent valve, as is normally the case when closing the closing mechanism. In contrast, if the threads are configured as left-hand threads, the valve element must be rotated counterclockwise to open the vent valve, as is normally the case with the closing mechanism. Thus, the operator can confirm that the vent valve is closed when the valve element cannot be rotated further clockwise.
[0023] The valve plate is preferably formed integrally with the valve element or the threaded shaft and abuts against the second axial end face of the valve housing at the first axial position of the valve element. Therefore, within the assembly range of the vent valve, the valve element needs to be screwed into the through hole of the valve housing, starting with the first end of the threaded shaft. To enable this, the rotating drive mechanism is the threaded head, which is attached as a separate part to the first end of the threaded shaft only after the valve element has been screwed into the valve housing. Consequently, the threaded head is not formed integrally with the threaded shaft in order to realize the assembly of the vent valve according to the present invention.
[0024] According to another embodiment, in order to allow a ventilation valve to be mounted to the ventilation opening of a vacuum pump, the valve housing has an external thread, via which the external thread and thus the ventilation valve can be screwed into the internal thread of the ventilation opening of the vacuum pump. In this case, as a rotation drive means, the valve housing has a regular polygonal structure between the external thread of the valve housing and an end face in a first axial direction, preferably with a hexagonal cross-section like a nut, in which case the aforementioned polygonal structure forms a radially aligned ring shoulder facing the external thread, and the ring shoulder is tightly clamped to the valve housing when the valve housing is screwed into the ventilation opening. In this case, preferably, the ring shoulder supports a ring seal, and in this case, in particular, the aforementioned ring seal may be a Usit ring seal, wherein it can be provided that the ring seal is vulcanized to a steel support ring concentric with the ring seal.
[0025] According to another aspect of the present invention, there is further provided for the first time a vacuum pump, in particular a turbomolecular vacuum pump, which is excellent in the features of claim 15. The vacuum pump has a housing, at least one pump stage is provided in the housing, a ventilation opening is formed in the housing, the ventilation opening communicates with the at least one pump stage, and the ventilation opening accommodates a valve housing of a ventilation valve formed according to one of claims 1 to 14.
[0026] Hereinafter, the present invention will be described based on exemplarily advantageous embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] [Figure 1] It shows a perspective view of a known turbomolecular pump. [Figure 2] It shows a bottom view of the turbomolecular pump of FIG. 1. [Figure 3] It shows a cross-sectional view of the turbomolecular pump along the section line A-A shown in FIG. 2. [Figure 4] It shows a cross-sectional view of the turbomolecular pump along the section line B-B shown in FIG. 2. [Figure 5]A cross-sectional view of a turbomolecular pump along the cutting line CC shown in Figure 2 is provided. [Figure 6] A schematic perspective view of the vent valve according to the present invention is shown. [Figure 7] Figure 8 shows a longitudinal cross-sectional view of the vent valve according to the present invention, drawn along the JJ line. [Figure 7a] Figure 7 shows a detailed, enlarged view of "K". [Figure 8] Figure 6 shows a front view of the vent valve. [Modes for carrying out the invention]
[0028] The turbomolecular pump 111 shown in Figure 1 has a pump intake port 115 surrounded by an intake flange 113. A recipient (not shown) may be connected to the pump intake port 115, as is known in itself. Gas arriving from the recipient can be drawn in from the recipient through the pump intake port 115 and pumped through the pump to the pump exhaust port 117.
[0029] An auxiliary vacuum pump, such as a rotary vane pump, may be connected to the pump exhaust port 117. The intake port flange 113 forms the upper end of the housing 119 of the vacuum pump 111 in the orientation of the vacuum pump shown in Figure 1. The housing 119 has a lower portion 121. An electronics housing 123 is located laterally on the lower portion 121. The electronics housing 123 houses the electrical and / or electronic components of the vacuum pump 111, for example, to operate an electric motor 125 (see also Figure 3) located inside the vacuum pump. The electronics housing 123 is provided with a number of connection points 127 for accessories. Furthermore, a data interface 129 (e.g., conforming to the RS485 standard) and a current supply connection point 131 are located in the electronics housing 123.
[0030] There are also turbomolecular pumps that do not have this type of attached electronic housing and are connected to external drive electronics.
[0031] The housing 119 of the turbomolecular pump 111 is provided with a ventilation intake 133, particularly in the form of a ventilation valve. The vacuum pump 111 may be vented through the ventilation intake 133. Further above the lower portion 121, a seal gas connection 135 (also referred to as a purge gas connection) is located. Through the seal gas connection 135, purge gas may be introduced into the motor chamber 137 to protect the electric motor 125 (see, for example, Figure 3) from the gas being pumped by the pump. The electric motor 125 is housed in the vacuum pump 111 within the motor chamber 137. Further above the lower portion 121, two coolant connection 139 are located. In this case, one coolant connection is provided as a coolant intake, and the other coolant connection is provided as an exhaust port. Coolant can be introduced into the vacuum pump for cooling purposes. Other turbomolecular vacuum pumps (not shown) that exist are operated exclusively by air cooling.
[0032] Since the lower surface 141 of the vacuum pump can be used as a base, the vacuum pump 111 may be operated in a vertical orientation with the lower surface 141 as the reference point. Furthermore, the vacuum pump 111 may be fixed to the recipient via the intake flange 113 and thus operated in a suspended state. Moreover, the vacuum pump 111 may be configured to operate even when it is aligned in a direction other than that shown in Figure 1. It is also possible to realize a vacuum pump configuration in which the lower surface 141 can be positioned sideways or upward instead of downward. In this case, in principle, any angle is possible.
[0033] In particular, other turbomolecular vacuum pumps (not shown) that are larger than the pump illustrated cannot be operated in a vertical configuration.
[0034] Various screws 143 are further positioned on the lower surface 141 shown in Figure 2. These screws 143 fasten components of the vacuum pump, which are not specifically identified here, to each other. For example, the bearing cover 145 is fixed to the lower surface 141.
[0035] The lower surface 141 is further provided with fixing holes 147. The pump 111 can be fixed to, for example, a mounting surface via these fixing holes 147. This is not possible with other turbomolecular vacuum pumps (not shown) that are larger than the pump shown.
[0036] Figures 2 to 5 show the coolant pipeline 148. Within the coolant pipeline 148, the coolant introduced and discharged via the coolant connection part 139 can be circulated.
[0037] As shown in the cross-sectional views of Figures 3 to 5, the vacuum pump has multiple process gas pump stages. The process gas pump stages are for pressurizing the process gas acting on the pump intake port 115 and sending it to the pump exhaust port 117.
[0038] A rotor 149 is positioned inside the housing 119. The rotor 149 has a rotor shaft 153 that is rotatable around a rotation axis 151.
[0039] The turbomolecular pump 111 has multiple turbomolecular pump stages connected in series to exert a pumping action. Each turbomolecular pump stage has multiple radial rotor blades 155 fixed to the rotor shaft 153, and multiple stator blades 157 positioned between the rotor blades 155 and fixed within the housing 119. In this case, one rotor blade 155 and one adjacent stator blade 157 each form one turbomolecular pump stage. The stator blades 157 are held apart from each other by spacer rings 159 at a desired axial distance.
[0040] The vacuum pump further comprises Holbeck pump stages arranged radially inward and outward from each other and connected in series to exert a pumping action. Another turbomolecular vacuum pump (not shown) exists that does not have Holbeck pump stages.
[0041] The rotor of the Holbeck pump stage has a rotor hub 161 positioned on the rotor shaft 153, and two cylindrical Holbeck rotor sleeves 163, 165 fixed to and supported by the rotor hub 161. The Holbeck rotor sleeves 163, 165 are oriented coaxially with respect to the axis of rotation 151 and are radially engaged with each other inward and outward. Two more cylindrical Holbeck status sleeves 167, 169 are provided. The Holbeck status sleeves 167, 169 are similarly oriented coaxially with respect to the axis of rotation 151 and are radially engaged with each other inward and outward.
[0042] The pumping surface of the Holbeck pump stage is formed by its sides, that is, by the radially inner and / or outer surfaces of the Holbeck rotor sleeves 163, 165 and the Holbeck status sleeves 167, 169. The radially inner surface of the outer Holbeck status sleeve 167 faces the radially outer surface of the outer Holbeck rotor sleeve 163, forming a radial Holbeck gap 171, and together with this outer surface, forms a first Holbeck pump stage that follows the turbomolecular pump. The radially inner surface of the outer Holbeck rotor sleeve 163 faces the radially outer surface of the inner Holbeck status sleeve 169, forming a radial Holbeck gap 173, and together with this outer surface, forms a second Holbeck pump stage. The radial inner surface of the inner Holbeck status sleeve 169 faces the radial outer surface of the inner Holbeck rotor sleeve 165, forming a radial Holbeck gap 175, and together with this outer surface, forms a third Holbeck pump stage.
[0043] A radially extending channel may be provided at the lower end of the Holbeck rotor sleeve 163. Through this channel, the radially outward-located Holbeck gap 171 is connected to the central Holbeck gap 173. A further radially extending channel may be provided at the upper end of the inner Holbeck stage sleeve 169. Through this channel, the central Holbeck gap 173 is connected to the radially inward-located Holbeck gap 175. This connects multiple Holbeck pump stages that engage with each other internally and externally in series. A further connecting channel 179 leading to the exhaust port 117 may be provided at the lower end of the radially inward-located Holbeck rotor sleeve 165.
[0044] The surfaces of the Holbeck status sleeves 167 and 169 that perform the aforementioned pumping action each have multiple Holbeck grooves that spiral around the rotation axis 151 and extend axially. On the other hand, the opposing sides of the Holbeck rotor sleeves 163 and 165 are smoothly formed and send the gas for operating the vacuum pump 111 forward within the Holbeck grooves.
[0045] For the rotatable support of the rotor shaft 153, a rolling bearing 181 is provided in the area of the pump exhaust port 117, and a permanent magnet type magnetic bearing 183 is provided in the area of the pump intake port 115.
[0046] In the region of the rolling bearing 181, a conical splash nut 185 is provided on the rotor shaft 153. The splash nut 185 has an outer diameter that increases toward the rolling bearing 181. The splash nut 185 is in sliding contact with at least one scraping member of the working medium reservoir. In other turbomolecular vacuum pumps (not shown), a splash screw may be provided instead of a splash nut. As a result, various configurations are possible, and in the above relationship, the term "splash tip" is also used.
[0047] The working medium storage unit has multiple absorbent disks 187 stacked vertically. These disks 187 are impregnated with a working medium for the rolling bearings 181, such as a lubricant.
[0048] During operation of the vacuum pump 111, the working fluid is transmitted by capillary action from the working fluid reservoir through the scraping member to the rotating splash nut 185, and then, based on centrifugal force, along the splash nut 185 toward the rolling bearing 181 toward the increasing outer diameter of the splash nut 185, where, for example, lubrication is performed. The rolling bearing 181 and the working fluid reservoir are surrounded within the vacuum pump by a tank-shaped insert 189 and a bearing cover 145.
[0049] The permanent magnet type magnetic bearing 183 has a rotor-side bearing half 191 and a stator-side bearing half 193. Each of these has one ring stack, which consists of multiple rings 195, 197 of permanent magnets stacked vertically in the axial direction. The ring magnets 195, 197 face each other, forming a radial bearing gap 199, in which case the rotor-side ring magnet 195 is positioned radially outward, and the stator-side ring magnet 197 is positioned radially inward. The magnetic field present in the bearing gap 199 causes a magnetic repulsive force between the ring magnets 195, 197. This repulsive force provides radial support for the rotor shaft 153. The rotor-side ring magnet 195 is supported by a support portion 201 of the rotor shaft 153. The support portion 201 surrounds the ring magnet 195 radially outward. The stator-side ring magnet 197 is supported by a support portion 203 of the stator side. The support portion 203 extends through the ring magnet 197 and is suspended from the radial support members 205 of the housing 119. Parallel to the axis of rotation 151, the rotor-side ring magnet 195 is fixed by a cover element 207 connected to the support portion 203. The stator-side ring magnet 197 is fixed in one direction parallel to the axis of rotation 151 by a fixing ring 209 and a fixing ring 211 connected to the support portion 203. A disc spring 213 may be further provided between the fixing ring 211 and the ring magnet 197.
[0050] An emergency bearing or safety bearing 215 is provided within the magnetic bearing. The emergency bearing or safety bearing 215 rotates freely without contact during normal operation of the vacuum pump, and only engages when the rotor 149 is excessively displaced radially relative to the stator, thereby forming a radial stopper for the rotor 149 so as to prevent collision between the rotor-side structure and the stator-side structure. The safety bearing 215 is configured as a non-lubricated rolling bearing and forms a radial gap with the rotor 149 and / or stator. This gap prevents the safety bearing 215 from engaging during normal pump operation. The safety bearing 215 engages upon radial displacement, and since the radial displacement is sufficiently large, the safety bearing 215 does not engage during normal operation of the vacuum pump, and at the same time is sufficiently small so that collision between the rotor-side structure and the stator-side structure is prevented in all situations.
[0051] The vacuum pump 111 has an electric motor 125 that rotates a rotor 149. The armature of the electric motor 125 is formed by the rotor 149. The rotor shaft 153 of the rotor 149 extends through a motor stator 217. A permanent magnet assembly may be positioned radially outward or embedded in the portion of the rotor shaft 153 that extends through the motor stator 217. An intermediate chamber 219 is positioned between the motor stator 217 and the portion of the rotor 149 that extends through the motor stator 217, and the intermediate chamber 219 has a radial motor gap. Through the motor gap, the motor stator 217 and the permanent magnet assembly may magnetically influence each other to transmit driving torque.
[0052] The motor stator 217 is fixed within the housing, in a motor chamber 137 provided for the electric motor 125. A seal gas (also called a purge gas, which may be, for example, air or nitrogen) can reach the motor chamber 137 via a seal gas connection 135. The electric motor 125 can be protected from process gases, such as corrosive parts of the process gas, via the seal gas. The motor chamber 137 may be evacuated via a pump exhaust port 117. That is, a vacuum pressure, at least approximately, is acting within the motor chamber 137, achieved by an auxiliary vacuum pump connected to the pump exhaust port 117.
[0053] A so-called labyrinth seal 223, which is known in itself, may be further provided between the rotor hub 161 and the wall portion 221 defining the motor chamber 137. This achieves better sealing of the motor chamber 217, particularly with respect to the Holbeck pump stage located radially outward.
[0054] As already mentioned above, the turbomolecular vacuum pump 111 can be vented through a vent valve 133, in this case, the vent valve 133 is a simple vent screw that is screwed into the vent opening of the corresponding housing 119. This vent valve 133 in the form of a simple vent screw can be replaced by a vent valve 10 according to the present invention, which is screwed into the vent opening of the pump housing 119 in an appropriate manner.
[0055] One embodiment of the vent valve 10 according to the present invention will be described below with reference to Figure 6.
[0056] The vent valve 10 shown in a perspective view in Figure 6 comprises a valve housing 12 and a valve element 14 housed within the valve housing 12. In this case, the valve housing 12 has male threads 50 on its outer circumferential surface, and the valve housing 12 is screwed into the vent opening of the vacuum pump 111 via the male threads 50. Furthermore, the valve housing 12 has a hexagonal contour 52, for example, a nut, formed on its outer circumference. In this case, the hexagonal contour 52 has a ring shoulder 54 on the side facing the male threads 50. Since the valve housing 12 is screwed into the vent opening of the vacuum pump 111 using a fork-type wrench via the hexagonal contour 52, the ring shoulder 54 tightly contacts the housing 119 via a ring seal (not shown), such as a Usit ring.
[0057] The valve housing 12 has a first axial end face 17 adjacent to the hexagonal contour 52 and a second axial end face 18 adjacent to the male threads 50. Between the two axial end faces 18, 20, a through hole 16 extends through the valve housing 12 and is provided with female threads 20, which transition into the second axial end face 18 via a conical recess 42.
[0058] Since the valve element 14 housed in the valve housing 12 has male threads 24, the shaft of the valve element 14 may also be referred to as the threaded body 22. Since the valve element 14 is screwed into the female threads 20 of the through opening 16 via the male threads 24, the axial position of the valve element 14 relative to the valve housing 12 can be changed by rotating the valve element 14. Preferably, in this case, the two threads 20, 24 referred to are formed as left-hand threads, so that the vent valve 10 can be opened by left-hand rotation of the valve element 14, as is generally the case with closing mechanisms.
[0059] To actuate the valve element 14, the valve element 14 has a pivot drive in the form of a screw head 28 at its first end 25, adjacent to the first axial end face 17 of the valve housing 12, which is not integrally formed with the screw body 22, and the screw head 28 is attached to the first end 25 of the screw body 22 only after the screw body 22 has been screwed into the through hole 16, with its first end 25 leading, and has been screwed through the through hole 16.
[0060] At the second end 26 opposite to the screw head 28, the screw body 22 has a valve plate 30 integrally formed with the screw body 22, and the valve plate 30 is used to seal the through hole 16 as needed. 7 As can be seen, the valve plate 30 has a frustoconical portion 44 formed complementary to the conical recess 32 on the side facing the second axial end face 18. Radially outward from the frustoconical portion 44, the valve plate 30 has a ring seal 46 on the side facing the second axial end face 18. The ring seal 46 is vulcanized in a steel support ring 47 concentric with the ring seal 46.
[0061] In particular, when the valve element 14 rotates clockwise, the valve plate 30 is unscrewed from the valve housing 12 until it contacts the second axial end face 18 of the valve housing 12 via the ring seal 46 provided in contact with the valve plate 30, thereby closing the through hole 16 and, consequently, the vent valve 10. This position of the valve element is also referred to here as the first axial position of the valve element 14. In this case, the ring seal 46 is pushed into the conical annular gap between the conical recess 42 and the conical portion 44, however, mechanical overloading of the elastomer material constituting the ring seal 46 is prevented by the support ring 47.
[0062] When the valve element 14 is rotated counterclockwise via the screw head 28 starting from the first axial position, the valve element 14 is screwed slightly into the valve housing 12, creating a gap A between the valve plate 30 and the second axial end face 18 of the valve housing 12. This position, where the valve plate 30 is separated from the second axial end face 18 by gap A, is also referred to here as the second axial position of the valve element 14. 7 This will be shown.
[0063] In the second axial position, the valve plate 30 does not tightly contact the second axial end face 18 of the valve housing 12, so based on the thread play between the female threads 20 of the valve hole 16 and the male threads 24 of the thread body 22, air reaches the interior of the pump 111 from the atmosphere through the through hole 16 or the thread play, thereby gradually ventilating the pump 111.
[0064] However, since the volumetric flow rate that can be generated by thread play is limited, according to the present invention, the threaded body 22 has an axial channel in the form of a blind hole 32 along its central axis, from which a first radial hole 38 branches off at its closed end 36. The first radial hole 38 opens into a ring groove 48 at the second end 36 of the threaded body 22. In this case, the depth of the ring groove 48 referred to is approximately equal to the thread height of the male threads 24 of the threaded body 22. Without this ring groove 48, the male threads 24 of the threaded body 22 would extend to the valve plate 30, thereby allowing the valve element 14 to be unscrewed until the valve plate 30 abuts against the second axial end face 18.
[0065] The first radial hole 38 opens at the second axial position of the valve element 14 in the gap A between the valve plate 30 and the second axial end face 18 of the valve housing 12, so that at the second axial position of the valve element 14, the external atmosphere enters the vacuum pump 11 through the blind hole 32 and the first radial hole 38 branching from the blind hole 32. flow The body is connected, and as a result, air can flow into the pump from the outside atmosphere through the bag hole 32 and the first radial hole 38, thereby ventilating the pump 111.
[0066] In particular, the figure 7a As can be seen from the enlarged detail view, the second radial hole 40 branches off from the sealed hole 32. In this case, the first radial hole 38 is located closer to the valve plate 30 than the second radial hole 40 and has a somewhat smaller diameter than the second radial hole 40. The diameter of the second radial hole 40 matches the diameter of the sealed hole 32.
[0067] In this case, the second radial hole 40 is used to achieve a second ventilation condition. The second ventilation condition is characterized in that the pump 111 can be ventilated at a volumetric flow rate greater than that obtained through the first radial hole 38 alone. This is based on the fact that the diameter of the second radial hole 40 is larger than that of the first radial hole 38. Since the second radial hole 40 is still located within the through hole 16 at the second axial position of the valve element 40 and therefore hardly allows any flow, the valve element 14 needs to be further screwed into the valve housing 12 in order to allow the pump 111 to be ventilated through the second radial hole 40. In such a third axial position, when both the first radial hole 38 and the second radial hole 40 open to the space between the valve plate 30 and the second axial end face 18 of the valve housing 12, which is enlarged relative to the second axial position, air enters the interior of the pump 32 from the atmosphere through the bag hole 32 and both radial holes 38 and 40. In other words, the valve element 14 can move to the aforementioned third axial position in order to allow the pump 111 to be ventilated as quickly as possible with air coming from the atmosphere, because in this third axial position, both radial holes 38 and 40 create a fluid connection between the external atmosphere and the interior of the pump 111. This application relates to the invention described in the claims, but also includes the following other embodiments. 1. In a vent valve (10) that opens and closes a vent opening in the housing (119) of a vacuum pump (111), particularly a turbomolecular vacuum pump (111), A valve housing (12) is housed in the vent opening of the vacuum pump (111), The valve element (14) is housed in the valve housing (12), Equipped with, A through hole (16) penetrates the valve housing (12), the through hole (16) extends from a first axial end face (17) to a second axial end face (18) of the valve housing (12) and has female threads (20), the valve element (14) has a threaded body (22) with male threads (24), the male threads (24) screw the valve element (14) into the female threads (20) of the through hole (16), and the threaded body (22) has a first end (25) that is connected to the valve housing (12) A vent valve (10) having a rotation drive device (28) for acting on the valve element (14) to change the axial position of the element (14), and having a valve plate (30) at a second end (26) opposite to the first end (25), wherein the valve plate (30) abuts against a second end face (18) of the valve housing (12) to seal the through hole (16) at the first axial position of the valve element (14), and the valve plate (30) has a gap (A) with respect to the second end face (18) at the second axial position of the valve element (14). 2. The screw body (22) has an axial channel (32), and the axial channel (32) provides a fluid connection through the screw body (22) for venting the vacuum pump only at a second axial position, which is the vent valve (10) described above. 3. The axial channel (32) is the vent valve (1) or 2 described above, having a blind hole (32) formed at the first end (25) of the screw body (22), which includes an open end (34) and a closed end (36). 4. The screw body (22) has at least one radial hole (38, 40) formed therein which is oriented substantially radially, and the radial hole (38, 40) branches off from the blind hole (32) and exits from the screw body (22) at the second end (26), thus forming the vent valve (10) of 3 described above. 5. The vent valve (10) of the 3 or 4, wherein the screw body (22) has a first radial hole (38) oriented substantially radially and at least one second radial hole (40) oriented substantially radially, and the entire first radial hole (38) is located closer to the valve plate (30) than the second radial hole (40). 6. The vent valve (10) of item 5, wherein the diameter of the second radial hole (40) is larger than the diameter of the first radial hole (38), and preferably the diameter of the second radial hole (40) is less than or equal to the diameter of the bag hole (32). 7. The through hole (16) transitions to the second axial end face (18) via a conical recess (42), and the valve plate (30) has a frustoconical portion (44) formed complementary to the conical recess (42) on the side facing the second axial end face (18), and the frustoconical portion (44) is housed by the conical recess (42) at the first axial position of the valve element (14), one of the 1 to 6 above, a vent valve (10). 8. The vent valve (10) of the above 7, wherein the valve plate (30) supports the ring seal (46) on the side facing the second axial end face (18) and radially outward of the frustoconical portion (44), and in particular, the ring seal (46) is vulcanized on a steel support ring (47) concentric with respect to the ring seal (46). 9. The screw body (22) has a groove (48) that circumfers adjacent to the valve plate (30) at the second end (25), and the groove (48) has a groove depth that matches or is greater than the thread height of the male thread (24) of the screw body (22), one of the above 1 to 8, air vent valve (10). 10. A vent valve (10) which is one of the above 1 to 9, wherein the male thread (24) of the screw body (22) and the female thread (20) of the valve housing (12) are formed as left-hand threads. 11. The screw body (22) has a first end (25) that supports a screw head attached to the first end (25) of the screw body (22) as a rotational drive device, and is one of the 1 to 9 above, a vent valve (10). 12. The valve housing (12) has male threads (24) for screwing the vent valve (10) into the vent opening of the vacuum pump (111), and in particular, the valve housing (12) has a regular polygonal contour (52) having a hexagonal cross-section, which is advantageous, between the male threads (24) of the valve housing (12) and the first axial end face (17), forming a radially aligned ring shoulder (54) facing the male threads (24). 13. The vent valve (10) described above, wherein the ring shoulder portion (54) supports the ring seal, and the ring seal is in particular a steel support ring concentric with respect to the ring seal that has been vulcanized. 14. The vent valve (10) has a locking mechanism, which acts between the valve housing (12) and the valve element (14) when the distance between the valve plate (30) and the second axial end face (18) of the valve housing (12) becomes a predetermined size, and is one of the vent valves (1) described in 1 to 13 above. 15. A vacuum pump (111), more particularly a turbomolecular vacuum pump (111), comprising a housing (119) having at least one pump stage, wherein a vent opening is formed in the housing (119), the vent opening is connected to at least one pump stage, and the vent opening houses the valve housing (12) of one of the 1 to 14 vent valves (10). [Explanation of Symbols]
[0068] 10. Ventilation valve 12 valve housing 14 valve elements 16 Through holes 17 First axial end face 18 Second axial end face 20 Female threads 22 Screw body 24 Male screw thread 25 22 First end 26 22 second end 28 Screw head / rotation drive unit 30 valve plate 32 Blind hole 34 Open end 36 Closed end 38 First radial hole 40 Second radial hole 42 Conical recess 44. The frustum-shaped part 46 Ring Seals 47 Support ring 48 Ring grooves 50 Male screw thread 52 Hexagonal outline 54 Ring shoulder area 111 Turbomolecular pump 113 Intake flange 115 Pump intake 117 Pump exhaust port 119 Housing 121 Lower part 123 Electronics Housing 125 Electric Motor 127 Accessory connection part 129 Data Interfaces 131 Current supply connection 133 Ventilation intake 135 Seal gas connection 137 Motor Room 139 Coolant connection part 141 Bottom surface 143 screws 145 Bearing cover 147 Fixed hole 148 Coolant piping 149 Rotor 151 Rotation axis 153 Rotor Shaft 155 Moving blade 157 Static Wing 159 Spacer Ring 161 Rotor Hub 163 Holbeck Rotor Sleeve 165 Holbeck Rotor Sleeve 167 Holbeck Status Leaf 169 Holbeck Status Leaf 171 Holbeck gap 173 Holbeck gap 175 Holbeck gap 179 connection channels 181 Rolling bearings 183 Permanent magnet type magnetic bearing 185 Splash Nut 187 discs 189 Inserts 191 Rotor-side bearing half 193 Stator-side bearing half 195 Ring Magnets 197 Ring Magnets 199 Bearing clearance 201 Support part 203 Support part 205 Radial support columns 207 cover elements 209 Support ring 211 Fixing ring 213 Disc spring 215 Emergency bearing or safety bearing 217 Motor Stator 219 Intermediate Room 221 Wall section 223 Labyrinth Seal A interval
Claims
1. In a vent valve (10) that opens and closes a vent opening in the housing (119) of a vacuum pump (111), A valve housing (12) is housed in the vent opening of the vacuum pump (111), The valve element (14) is housed in the valve housing (12), Equipped with, A through hole (16) penetrates the valve housing (12), the through hole (16) extends from a first axial end face (17) to a second axial end face (18) of the valve housing (12) and has female threads (20), the valve element (14) has a threaded body (22) with male threads (24), the male threads (24) screw the valve element (14) into the female threads (20) of the through hole (16), the threaded body (22) has a first end (25) to change the axial position of the valve element (14) relative to the valve housing (12) The valve element (14) has a rotating drive device (28) for operating it, and has a valve plate (30) at a second end (26) opposite to the first end (25), the valve plate (30) abuts against the second end face (18) of the valve housing (12) to seal the through hole (16) at a first axial position of the valve element (14), the valve plate (30) has a gap (A) with respect to the second end face (18) at a second axial position of the valve element (14), and a gap (A) greater than the gap (A) with respect to the second end face (18) at a third axial position of the valve element (14), The screw body (22) has an axial channel (32), and the axial channel (32) provides a fluid connection through the screw body (22) for venting a vacuum pump at a second axial position. The axial channel (32) has a blind hole (32) formed at the first end (25) of the screw body (22), which includes an open end (34) and a closed end (36). The screw shaft (22) has a first radial hole (38) oriented substantially radially on the side closer to the valve plate (30), and at least one second radial hole (40) oriented substantially radially, wherein the entire first radial hole (38) is located closer to the valve plate (30) than the second radial hole (40), and the first radial hole (38) and the second radial hole (40) branch off from the blind hole (32) and retract from the screw shaft (22) at the second end (26). A vent valve (10) wherein, at a second axial position of the valve element (14), the first radial hole (38) opens at the distance (A) relative to the second end face (18), and at a third axial position of the valve element (14), the first radial hole (38) and the second radial hole (40) open at a distance greater than the distance (A) relative to the second end face (18).
2. The vent valve (10) according to claim 1, wherein the diameter of the second radial hole (40) is larger than the diameter of the first radial hole (38).
3. The through hole (16) transitions to the second axial end face (18) via a conical recess (42), and the valve plate (30) has a frustoconical portion (44) formed complementary to the conical recess (42) on the side facing the second axial end face (18), and the frustoconical portion (44) is housed by the conical recess (42) at the first axial position of the valve element (14), the vent valve (10) according to claim 1.
4. The vent valve (10) according to claim 3, wherein the valve plate (30) supports the ring seal (46) on the side facing the second axial end face (18) and radially outward of the frustoconical portion (44).
5. The vent valve (10) according to claim 1, wherein the screw body (22) has a groove (48) that circumfers adjacent to the valve plate (30) at the second end (26), and the groove (48) has a groove depth that matches or is greater than the thread height of the male thread (24) of the screw body (22).
6. The vent valve (10) according to claim 1, wherein the male threads (24) of the screw body (22) and the female threads (20) of the valve housing (12) are formed as left-hand threads.
7. The vent valve (10) according to claim 1, wherein the screw body (22) supports the screw head attached to the first end (25) of the screw body (22) as a rotational drive device at the first end (25).
8. The vent valve (10) according to claim 1, wherein the valve housing (12) has male threads (50) for screwing the vent valve (10) into the vent opening of the vacuum pump (111).
9. The vent valve (10) according to claim 8, wherein the valve housing (12) has a regular polygonal contour portion (52) between the male thread (50) of the valve housing (12) and the first axial end face (17), forming a ring shoulder portion (54) that is radially aligned toward the male thread (50).
10. The vent valve (10) according to claim 9, wherein the contour portion (52) has a hexagonal cross-section.
11. The vent valve (10) according to claim 9, wherein the ring shoulder portion (54) supports a ring seal, and the ring seal is vulcanized on a steel support ring concentric with respect to the ring seal.
12. The vent valve (10) according to claim 1, wherein the vent valve (10) has a locking mechanism, and the locking mechanism acts between the valve housing (12) and the valve element (14) when the distance between the valve plate (30) and the second axial end face (18) of the valve housing (12) becomes a predetermined size.
13. A vacuum pump (111) comprising a housing (119) having at least one pump stage, wherein a ventilation opening is formed in the housing (119), the ventilation opening is connected to at least one pump stage, and the ventilation opening houses the valve housing (12) of the ventilation valve (10) according to claim 1 or 2.
14. The vent valve (10) according to claim 1, wherein the vacuum pump (111) is a turbomolecular vacuum pump (111).
15. The ventilation valve (10) according to claim 1, wherein the diameter of the second radial hole (40) is less than or equal to the diameter of the bag hole (32).
16. The vent valve (10) according to claim 4, wherein the ring seal (46) is vulcanized on a steel support ring (47) that is concentric with respect to the ring seal (46).
17. The vacuum pump (111) is a turbomolecular vacuum pump (111) according to claim 13.
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