DE102017119596A1 - Hermetic vacuum pump shut-off valve - Google Patents

Abstract

A vacuum pump shut-off (VPI) valve is disposed between a vacuum pump and a vacuum chamber. During normal operation of the vacuum pump, the VPI valve is open allowing fluid communication between the vacuum pump and the vacuum chamber. When the vacuum pump becomes inoperable, eg, loses power, the VPI closes valve, thereby isolating the vacuum chamber from the vacuum pump. The closing of the VPI valve is driven by the exhaust pressure of the vacuum pump. The VPI valve is exposed to the exhaust pressure by opening a pilot valve, which may occur as a result of an operation of the vacuum pump being stopped. By virtue of this configuration, the VPI valve is hermetic and does not require ambient air for its operation.

Description

Technical area

The present invention generally relates to a shut-off valve which is used with a vacuum pump to protect an associated vacuum system in the event of disconnection of the vacuum pump. In particular, the invention relates to a shut-off valve which is driven by means of a gas pressure within the vacuum pump to close.

background

Various systems include one or more internal chambers which must operate at a high vacuum (very low, subatmospheric pressure) level, for example, lower than 10 ^-3 Torr. Such systems include, for example, spectrometry systems, leak test systems, microscopes (eg electron microscope) systems, microfabrication (eg vacuum deposition) systems, etc. The internal vacuum chambers of these systems are emptied by means of one or more vacuum pumps. For example, a vacuum system may include a roughing pump or a backing pump configured to bring the vacuum system down to a coarse vacuum level, for example, down to about 10 ^-3 torr. The vacuum system may further include one or more high vacuum pumps configured to further bring the vacuum system down to a high vacuum level. In such a system, the coarse pump serves as a first stage of vacuum evacuation and may be required for operation of the further stage (s) of high vacuum evacuation implemented by the high vacuum pump.

The vacuum system may include a vacuum pump shut-off (VPI) valve configured to automatically shut off and protect components of the high vacuum system from high pressures (eg, ambient or atmospheric pressure) in the event that the backing pump loses power, and then reopen only after the forepump has been restarted and created a sufficient vacuum level that is safe for further operation of the components of the high vacuum system. For example, high vacuum pumps, such as turbomolecular pumps, are irreparably damaged when subjected to pressures well above about 200 mTorr when running at full speed. Typically, a VPI valve is disconnected from the forepump and connected to the environment, i. with the environment outside the forepump and the rest of the vacuum system. Therefore, using the conventional VPI valve results in a non-hermetic system.

1 is a schematic view of an example of a vacuum system 100 which is a conventional VPI valve 114 starts. The vacuum system 100 contains a forepump 118 , which with a high vacuum stage 122 of the vacuum system 100 via the VPI valve 114 connected is. The forepump 118 is typically a mechanical pump, such as a scroll pump, a rotary vane pump, a diaphragm pump, a Roots blower (positive displacement lobe), etc. The high vacuum stage 122 contains one or more vacuum chambers 126 ie internal spaces to be evacuated, those with the forepump 118 are connected. The high vacuum stage 122 also includes one or more high vacuum pumps 130 (eg, a turbomolecular pump, an ion sputtering pump, etc.) configured to empty the vacuum chamber (s) 126 to a vacuum level which exceeds the vacuum level by means of the forepump 118 alone could be achieved. During normal operation of the vacuum system 110 is the VPI valve 114 open, ie it provides an unrestricted working gas flow path from the high vacuum stage 122 to an inlet 134 the forepump 118 ready. The VPI valve 114 typically includes a movable piston which during normal operation of the vacuum system 100 is open (not seated (unseated)). The forepump 118 discharges the gas at an outlet 138 of it in an exhaust pipe 142 ,

The vacuum system 100 also includes another valve, for example a solenoid valve 146 which provides a selective connection between the environment and the VPI valve 114 (Namely, between the environment and the side of the VPI valve piston, which the working gas flow path between the high vacuum stage 122 and the forepump 118 opposite). The solenoid valve 146 is typically a normally open valve in the sense that it requires electrical power to be actively held in a closed state, which is the VPI valve 114 isolated from the environment. The same power source may be used to provide power to both the solenoid valve 146 as well as to the forepump 118 be used. During normal operation of the vacuum system 100 is the solenoid valve 146 closed. If, however, the forepump 118 loses power, opens the solenoid valve 146 , thereby the ambient air 150 is possible in the VPI valve 114 to stream. The resulting pressure difference across the piston of the VPI valve 114 forces the piston to become seated, thereby causing the working gas flow path between the high vacuum stage 122 and the forepump 118 is completed and the high vacuum stage 122 is isolated from the higher pressure resulting from the switching off of the forepump 118 developed.

Other specific examples of the previous VPI configuration are the U.S. Patent No. 4,785,851 described.

As can be seen from the foregoing, the conventional configuration of the vacuum system 100 not hermetic in that the isolation / protection phase of the operation involves exposure to the environment. However, there are many applications in which exposure to the environment is disadvantageous, for example, applications involving recirculation of helium or certain chemicals where air should not be allowed to enter the system and working gas should not be allowed to leave the system. Therefore, a need exists for vacuum systems that involve the use of a VPI valve which are hermetic.

Summary

To address the above-described problems, in whole or in part, and / or other problems that have been observed by those skilled in the art, the present disclosure provides methods, processes, systems, apparatus, instruments, and / or apparatuses, as exemplified in U.S. Pat described in the implementations described below.

According to one embodiment, a vacuum pump shut-off (VPI) valve includes: a pump inlet housing enclosing an inlet interior; a valve element disposed in the inlet interior, wherein the valve element is configured to switch between an open state of the VPI valve and a closed state of the VPI valve and configured to switch to the closed state in response to pressure, wherein open state, the valve element allows fluid flow between a vacuum pump and a vacuum chamber via the inlet interior, and in the closed state, the valve element blocks fluid flow between the vacuum pump and the vacuum chamber; and a pilot valve configured to connect to the inlet interior and an internal exhaust conduit of the vacuum pump, the pilot valve being switchable between an open pilot valve position and a closed pilot valve position, wherein in the open pilot valve position the pilot valve allows exhaust gas from the internal exhaust conduit, pressure acting on the valve element, which is operative to switch the valve element to the closed state, and in the closed pilot valve position, the pilot valve blocks the flow of exhaust gas from the internal exhaust passage to the valve element.

In another embodiment, a vacuum pump includes: a VPI valve according to any of the embodiments disclosed herein; a pump body, wherein the internal exhaust pipe is disposed in the pump body; a first exhaust gas transfer line providing fluid communication between the internal exhaust gas line and the pilot valve; and a second exhaust gas transfer line providing fluid communication between the pilot valve and a control volute chamber.

According to another embodiment, a vacuum pump shut-off (VPI) valve includes: a valve seat disposed in the inlet interior; a piston disposed in the inlet interior, the piston being movable between an open piston state and a closed piston state, wherein in the open piston state, the piston allows fluid flow between a vacuum pump and a vacuum chamber via the inlet interior, and in the closed piston state Piston touches the valve seat and blocks the fluid flow between the vacuum pump and the vacuum chamber; a control volumetric chamber disposed in the inlet interior and defined at least partially by the piston, movement of the piston changing a volume of the control volumetric chamber; and a pilot valve configured to connect to the control volumetric chamber and an internal exhaust conduit of the vacuum pump, the pilot valve being switchable between an open pilot valve position and a closed pilot valve position, wherein in the open pilot valve position, the pilot valve permits exhaust from the internal exhaust conduit, the control volumetric chamber pressurizing to a pressure effective to move the piston to the closed piston state, and wherein in the closed pilot valve position, the pilot valve shuts off exhaust flow from the internal exhaust passage to the control volute chamber.

In another embodiment, a vacuum pump includes: a VPI valve according to any of the embodiments disclosed herein; a pump body, wherein the internal exhaust pipe is disposed in the pump body; a first exhaust gas transfer line providing fluid communication between the internal exhaust gas line and the pilot valve; a second exhaust gas transfer line providing fluid communication between the pilot valve and the inlet interior.

According to another embodiment, a vacuum system includes: a vacuum pump, which has an internal exhaust pipe; a vacuum chamber; and a VPI valve according to any of the embodiments disclosed herein.

 The vacuum pump may include a pump stage disposed in the pump body and connected to the inlet interior and the internal exhaust gas line. The pump stage may include one or more stationary pumping elements and movable pumping elements. The movable pump element (e) can be driven (powered) by means of a motor (e.g., an electric motor) of the vacuum pump. In some embodiments, the vacuum pump is a scroll pump. The scroll pump may have a scroll pump stage. The scroll pump stage may include a stationary scroll and a scroll that is drivable to orbit relative to the stationary scroll, as will be appreciated by those skilled in the art.

Other apparatus, devices, systems, methods, features, and advantages of the invention will become apparent to those skilled in the art upon review of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages included within this description be within the scope of the invention and protected by the appended claims.

Brief description of the drawings

The invention will be better understood by reference to the following figures. The components in the figures are not necessarily to scale, instead the emphasis is on an illustration of the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout different views.

1 Fig. 10 is a schematic view of an example of a vacuum system employing a conventional vacuum pump shut-off (VPI) valve.

2 FIG. 12 is a schematic view of an example of a vacuum system according to an embodiment disclosed herein. FIG.

3A Fig. 3 is a partially cutaway perspective view of an example of a part of a vacuum pump according to an embodiment disclosed herein, illustrating a VPI valve of the vacuum pump in an open position.

3B is a partially cutaway perspective view of a vacuum pump, similar to the view of 3A However, the VPI valve is in a closed position.

4 is a partially sectioned side view of the vacuum pump, which in the 3A and 3B is shown.

5 is a partially sectioned plan view of the vacuum pump, which in the 3A . 3B and 4 with the VPI valve and an associated pump inlet of the vacuum pump removed.

Detailed description

As used herein, the term "vacuum chamber" includes a chamber (ie, an enclosed space adapted to be fluidly sealed in a vacuum-tight manner) which is part of or in fluid communication with a vacuum pump, as is disclosed herein. Depending on the context or operating stage, vacuum pressure exists in a "vacuum chamber" (eg subatmospheric pressure to 10 ^-9 Torr or lower) as a result of operation of the vacuum pump (ie, the vacuum chamber has been drained), or at least is suitable Vacuum pressure to be pumped down because the vacuum chamber is part of the vacuum pump or in fluid communication with the vacuum pump. In general, depending on the application, the vacuum chamber may be a device or system, or part of a device or system employing a deflated area, such as a scientific instrument or a manufacturing instrument. Examples of scientific instruments include, but are not limited to, mass spectrometers, ion mobility spectrometers, gas leak detectors and electron microscopes. Examples of manufacturing instruments include, but are not limited to, instruments employing deflated reaction chambers for making microelectronic, microelectromechanical systems (MEMS), microfluidics, and the like. Such manufacturing instruments may employ, for example, techniques involving vacuum deposition, plasma generation, electron beam generation, molecular beam generation, ion implantation, and the like, as will be apparent to those skilled in the art.

2 is a schematic view of an example of a vacuum system 200 according to an embodiment disclosed here. The vacuum system 200 contains at least one vacuum pump. In the present embodiment, the vacuum system includes 200 a forepump 218 , The forepump 218 Includes a vacuum pump shut-off (VPI) valve 214 , a pump inlet 234 , which with a high vacuum stage 222 of the vacuum system 200 via the VPI valve 214 connected, and a pump outlet 238 which gas into a main exhaust pipe 242 discharges. The forepump 218 may be a mechanical pump as described above. The high vacuum stage 222 contains one or more vacuum chambers 226 , which with the forepump 218 are connected. The high vacuum stage 222 may also include one or more high vacuum pumps 230 included as described above. The forepump 218 Also includes a first exhaust gas transmission line or a connection 254 which provides fluid communication between the main exhaust line 242 and a pilot valve 246 provides, and a second Abgastransferleitung or connection 258 which provides fluid communication between the pilot valve 246 and the VPI valve 214 provides. The VPI valve 214 and the exhaust gas transmission lines 254 and 258 are separate from the forepump 218 shown schematically, for purposes of illustration. In some embodiments, the VPI valve is 214 however integrated or internal in the main structure or a housing of the forepump 218 , The exhaust gas transmission lines 254 and 258 can also be integrated or internal in the main structure or the housing of the forepump 218 be. In other embodiments, all or part of the first exhaust gas transfer line 254 and the pilot valve 246 outside the main structure or the housing of the forepump 218 be arranged.

In general, the pilot valve 246 be any type of valve that is capable of being operated in an open state and a closed state. In a typical, previously non-exclusive embodiment, the pilot valve is 246 configured as a normally open valve, ie the pilot valve 246 requires electrical power to be kept active in the closed state. For example, the pilot valve 246 be a solenoid-operated valve. The same power source (eg a 24-V power source) can be used to connect both the pilot valve 246 as well as the forepump 218 to provide power.

The following is an example of operating the vacuum system 300 described. In this example contains the vacuum system 200 both the forepump 218 , which provides a first vacuum pump stage, as well as at least one high vacuum pump 230 which provides at least one additional vacuum pump stage.

Starting with the pre-pump switched off 218 are internal areas of the vacuum system 200 , for example, the forepump 218 and the vacuum chamber 226 , at atmospheric pressure, and the VPI valve 214 is open. The VPI valve 214 typically includes a moveable valve member, such as a piston, which may be biased by spring into an open (unseated) position, as described below. The normally open pilot valve 246 is also open at this time. When the forepump 218 is then started, the pilot valve 246 powered, what the pilot valve 246 causes it to close (eg, by energizing a magnet), thereby causing the VPI valve 214 from the discharge / exhaust side of the forepump 218 is isolated. The VPI valve 214 remains open at this time. Because the forepump 218 is in operation, a vacuum begins in the high vacuum stage 222 to develop. Subsequent operation of the high vacuum pump 230 brings the vacuum to the level required for the intended use of the vacuum chamber 226 is required.

If the forepump 218 subsequently loses power, for example, is switched off or turns off due to a power error or a power supply error, opens the pilot valve 246 , For example, in the case of a solenoid-based pilot valve, the pilot valve is lost 246 also at power, causing the solenoid is turned off, which is the pilot valve 246 causes it to move to its normally open position. With the open pilot valve 246 is now one side of the VPI valve 214 the pressure of the exhaust gas via the first Abgastransferleitung 254 , the pilot valve 246 and the second exhaust gas transmission line 258 exposed. For example, the exhaust pressure may be at or about atmospheric pressure, but in any event is much higher than the pressure in the deflated areas on the other side of the VPI valve 214 , As a result, a pressure difference develops across the VPI valve 214 which is big enough, the VPI valve 214 close. For example, as further described herein, the VPI valve may 214 Contain a spring-biased piston, which is forced by the exhaust pressure to push against the biasing force of the spring against the seat (to become seated). The VPI valve 214 can be configured to open the pilot valve 246 close quickly (eg in a few milliseconds). Closing the VPI valve 214 closes the working gas flow path (lines 262 and 266 in 2 ) between the high vacuum stage 222 and the forepump 218 from. In this way, the high vacuum level becomes in the high vacuum stage 222 Maintain until the forepump 218 becomes operational again.

When the forepump 218 is restarted, the pilot valve closes 246 again. Exhaust gas is removed from the VPI valve 214 away and into the pump inlet 234 the forepump 218 drawn. When the pressure in the VPI valve 214 low enough, the VPI valve opens 214 again, causing the High vacuum stage 222 with the forepump 218 is coupled again.

From the foregoing, it will be seen that the VPI valve 214 is driven to close by means of an internal mechanism, namely the pressure of an internally conducted exhaust stream. Ambient air is not used and does not enter the vacuum system 200 one. Therefore, the forepump provides 218 a hermetic solution for vacuum pump isolation ready.

3A Fig. 16 is a partially cutaway perspective view of an example of a part of a vacuum pump 318 which is a VPI valve 341 according to one embodiment. The vacuum pump 318 and the VPI valve 314 may be provided as part of a vacuum system. Accordingly, for example, the vacuum pump 318 and the VPI valve 314 to the forepump 218 and the VPI valve 214 of the vacuum system 200 correspond, which is described above and which in 2 is shown.

The vacuum pump 318 generally contains a pump body 320 , which is a pump interior 324 encloses. Stationary and movable pumping elements (not shown) are inside the pump 324 arranged. The configuration of the pump elements (eg, scrolls, vanes, lobes, etc.) is of the particular embodiment of the vacuum pump 318 dependent. The vacuum pump 318 contains a pump inlet 334 , In the present embodiment, the pump inlet 334 by means of a pump inlet housing (or pump inlet flange) 336 defined, which with the pump body 320 coupled in a vacuum-tight manner. The pump inlet housing 336 is configured to be fluidly coupled to a vacuum system (a high vacuum stage as described above), such as by an arrow 322 in 3 indicated. The pump inlet housing 336 includes a pump inlet port 340 in which the VPI valve 314 is positioned. The VPI valve 314 is positioned such that the pump inlet 334 selectively a fluid connection between the pump interior 324 and the rest of the vacuum system (high vacuum stage) 322 depending on the condition of the VPI valve 314 ,

3A puts the VPI valve 314 in an open state. In the open state, the VPI valve allows 314 in that gas (due to the operation of the pump elements of the vacuum pump 318 ) free from the vacuum system 322 via the pump inlet connection 340 into the pump inlet 334 and into the pump interior 324 flows as generally by means of an arrow 344 indicated. For this purpose, the VPI valve 314 include a movable member which is movable between an open position corresponding to the open state and a closed position corresponding to the closed state. The closed position of the movable element, and thus the closed state of the VPI valve 314 are in 3B shown as described below.

In the present embodiment, the VPI includes valve 314 a movable element in the form of a piston 348 , The piston 348 is linearly movable (in the vertical direction from the perspective of 3A ) between the open position ( 3A ) and the closed position ( 3B ). The linear movement or translation of the piston 348 can by means of a piston guide 352 be guided. In the present embodiment, the piston guide 352 the shape of a stationary pin, which is extended in the direction of piston movement and into a central bore of the piston 348 extends. The piston 348 may be in the direction of the illustrated open position by means of a suitable spring 356 be biased, which the piston 348 surrounds and by means of one or more outer surfaces of the piston 348 and inner surfaces of the pump inlet housing 336 is held. Also in this embodiment, the piston contains 348 a first piston part (or main piston body) 360 and a second piston part 364 (or piston nut) which (for example by means of a threaded engagement) on the first piston part 360 is attached. The piston guide 352 extends through a central bore of the second piston part 364 and in a central bore of the first piston part 360 ,

The VPI valve 314 also includes an annular membrane 368 which consists of a suitable flexible material (eg rubber). The membrane 368 is on the piston 348 and at the pump inlet housing 336 and / or the pump body 320 attached. More specifically, in the illustrated embodiment, the inner peripheral region of the membrane 368 between the first piston part 360 and the second piston part 364 clamped, and the outer peripheral region of the membrane 368 is between the pump inlet housing 336 and the pump body 320 clamped. As shown, the outer peripheral region of the membrane 368 an annular head contained in an annular groove of the pump inlet housing 336 is positioned.

3B is a partially cutaway perspective view of the vacuum pump 318 , similar to the view 3A which the VPI valve 314 but in a closed position. How best in 3B is shown, is a variable volume Control volume chamber 342 by means of the piston 348 (namely the second piston part 364 ), the membrane 368 , and a surface 376 of the pump body 320 defined (limited) which the piston 348 axially opposite and the piston 348 facing (in particular the second piston part 364 ). The volume of the control volume chamber 370 has a minimum value when the piston 348 in the open position ( 3A ), which from the perspective of 3A and 3B the lowest position is. In the open position, the piston can 348 (namely the second piston part 364 ) against the pump body surface 376 nudge. In some embodiments and as in 3A shown, in the open position, a part of the membrane 368 to be folded on itself. On the other hand, the volume of the control volume chamber expands 370 to a maximum when the piston 348 is moved to the closed position ( 3B ), what from the perspective of 3A and 3B the topmost position is. As in 3B is shown, in the closed position, the piston abuts 348 (namely the first piston part 360 ) against an annular valve seat 380 at. The valve seat 380 may be on an inner surface of the pump inlet housing 336 be formed. To the sealing interface between the piston 348 and the valve seat 380 In the closed position, the valve seat can improve 380 may be constructed (eg, machined) to have a smoother surface (with less surface roughness) than other interior surfaces that are not used for sealing. In addition, the piston can 348 a sealing element 384 (For example, an O-ring, which in an annular groove of the first piston part 360 positioned) containing the valve seat 380 contacted and to some extent between the piston 348 and the valve seat 380 can be deformed, to contact the valve seat 380 out. As further in 3B shown is the spring 356 compressed in the closed position.

As in the embodiment described above and as in 2 shown, contains the vacuum pump 318 a Abgastransferleitung, which from a main exhaust pipe of the vacuum pump 318 to the VPI valve 314 runs, and a pilot valve, which is operatively positioned in the exhaust gas transfer line to alternately close the exhaust gas transfer line (to block the gas flow therethrough) and to open the exhaust gas transfer line (to allow the gas flow therethrough). Examples of components composing the exhaust gas transfer pipe and the pilot valve will now be described with reference to FIGS 3A . 3B . 4 and 5 described.

4 is a partially sectioned side view of the vacuum pump 318 which in the 3A and 3B is shown. Relative to the view of 3A and 3B is the view of 4 rotated around a vertical axis. As in 4 shown, contains the vacuum pump 318 a pilot valve 488 , As previously described in the present disclosure, the pilot valve may 488 in general, any type of valve capable of being operated in an open state and a closed state. In a typical, previously non-exclusive embodiment, the pilot valve is 488 configured as a normally open valve, ie the pilot valve 488 requires electrical power to be kept active in the closed state. For example, the pilot valve 488 be a solenoid-operated valve. A power source supplies the pilot valve 488 via a suitable electrical wiring 490 with power. The same power source (eg, a 24-volt power supply) can be used to connect both the pilot valve 488 as well as the engine of the vacuum pump 318 to power which drives the movable pump element (s) (eg, the orbiting scroll of a scroll pump). The pilot valve 488 can be between a first gas-conducting block (or bracket) 492 and a second gas-conducting block (or holder) 394 be mounted. The pilot valve 488 , the first gas-conducting block 492 and the second gas-conducting block 394 can outside the pump body 320 be positioned.

The vacuum pump 318 contains a main exhaust pipe 442 which removes the gas processed by the pumping elements away from the discharge side of the vacuum pump 318 as will be apparent to those skilled in the art. As noted above, in the present embodiment, the main exhaust gas passage is 442 with the pilot valve 488 connected, and in turn with the VPI valve 314 ( 3A and 3B ) connected via an exhaust gas transmission line. In the present embodiment, the exhaust gas transport pipe is collectively formed or defined by means of a plurality of gas passages (internal passages). The gas channels are separated from each other in that they are arranged in different solid structures. Adjacent gas channels are interconnected at fluid-tight connections where various fixed structures are interfaced and / or optionally via fluidic fittings.

In the embodiment which is specific in 4 is shown, the Abgastransferleitung includes a first gas channel 421 which is in an outer housing 423 of the pump body 320 is arranged and which with the main exhaust gas line 442 (which also in the outer housing 423 is arranged) is fluidically coupled, a second gas channel 425 which is in a cast frame 427 of the pump body 320 is arranged and which with the first gas channel 421 is fluidically coupled, a third gas channel 429 (partially shown), which in the first gas-conducting block 492 is arranged and which with the second gas channel 425 is fluidically coupled, a fourth gas channel 531 (in 4 not shown in 5 partially shown), which is in the pilot valve 488 is arranged and which with the third gas channel 429 is fluidically coupled, and a fifth gas channel 333 (in 4 not shown in the 3A and 3B partially shown), which is in the second gas-conducting block 394 is arranged and which is fluidically coupled to the fourth gas channel. While in the partially sectioned view of 4 only part of the third gas channel 429 is shown and the fourth and fifth gas channels are not shown by name, is the gas flow through the first gas-conducting block 492 , the pilot valve 488 , and the second gas-conducting block 394 by means of a dashed line 435 shown schematically. The fluidic couplings or interfaces between different gas channels may be fluid sealed by any suitable means. For example 4 the provision of sealing elements 433 , For example, O-rings, dar.

3A and 3B show the second gas-conducting block 394 and parts of its internal fifth gas channel 333 , In the embodiment, which in particular in the 3A and 3B is shown, the exhaust gas transmission line further includes a sixth gas channel 339 which is in the pump body 320 (For example, in the cast frame 427 ) is arranged and which with the fifth gas channel 333 is fluidically coupled. From the perspective of 3A and 3B contains the sixth gas channel 339 a horizontal part, which with the fifth gas channel 333 is fluidically coupled and which leads to a vertical part, which in open communication with the control volume chamber 370 is ( 3B ). In the open (lowered) position of the piston 348 , what a 3A shown, the piston can 348 (namely the second piston part 364 ), but need not, the fluid flow between the sixth gas channel 339 and the control volume chamber 370 lock. In any case, the gas flow through the exhaust gas transfer line is by means of the state (open or closed) of the pilot valve 488 specified.

5 is a partially sectioned plan view of the vacuum pump 318 which in the 3A . 3B and 4 is shown, wherein the VPI valve 314 and the associated pump inlet 334 ( 3A and 3B ) is removed. The cut passes through a plane passing through the pilot valve 488 , the second gas-conducting block 394 , and a part of the pump body 320 below the control volume chamber 370 runs ( 3B ). The sectional plane is arranged such that the third gas channel 429 ( 4 ) of the first gas-conducting block 492 not shown, only part of the fourth gas channel 531 the pilot valve 488 is shown, only part of the fifth gas channel 333 of the second gas-conducting block 394 is shown, and only parts of the sixth gas channel 339 (a part of the horizontal part and the cross section of the vertical part shown in Figs 3A and 3B ) in the pump body 320 are shown. The gas flow through the parts of these gas channels, which are not shown, is schematically indicated by the dashed line 536 displayed. The fourth gas channel 531 can by means of one or more internal passages of the pilot valve 488 be defined. Depending on its configuration, the pilot valve may 488 one or more valve elements (typically at least one movable valve element) containing the pilot valve 488 between its open and closed states and thereby the gas flow through the pilot valve 488 controls and thus the exhaust gas transmission line.

The vacuum pump 318 can generally be as above in terms of the embodiment 2 described, operated. Assuming that the vacuum pump 318 was not operated, the inner areas of the vacuum pump 318 and other parts of the system connected to the vacuum pump 318 (such as the vacuum stage 322 ) at ambient pressure (eg, atmospheric pressure). At this time, the VPI valve 314 in the open state, as the piston 348 by means of the spring 356 is biased in the open positions, which in 3A is shown. Also at this time is the normally open pilot valve 488 also in its open state, since no power to the pilot valve 488 is fed to move it to its closed position.

The vacuum pump 318 can then be started by the motor of the vacuum pump 318 is supplied with power. At this time will also be the pilot valve 488 powered, causing it to be switched to the closed state and held, thereby blocking an exhaust flow in the exhaust gas delivery line and thus the VPI valve 314 from the main exhaust pipe 442 is isolated. At this time, the vacuum pump works 318 normal. The vacuum pump 318 develops a vacuum at its intake side and in the vacuum stage 322 by the vacuum pump 318 Gas molecules from the vacuum stage 322 via the pump inlet 334 into the pump interior 324 withdraws (as generally by means of the arrow 344 in 3A pictured) and the gas molecules in the main exhaust gas line 442 in the discharge side of the vacuum pump 318 transferred. The VPI valve 314 remains in its open state, as the gas pressure in the control volumetric chamber 342 not sufficient to overcome the preload force acting on the piston 348 by means of the spring 346 is transmitted. As in the 3A and 3B shown, the vacuum pump 318 an opening 339 included with a small diameter, which a gas line limited fluid communication between the pump inlet port 340 and the control volume chamber 372 provides. The opening 339 can compensate for the pressure in the control chamber 372 with the vacuum pressure in the pump inlet port 340 serve. Therefore, during normal operation, the vacuum pump exists 318 no pressure difference across the piston 348 ,

If at a time during normal operation, the vacuum pump 318 is switched off, either intentionally or due to an operating error, loses the pilot valve 488 also in power and switches to its open state. Consequently, the control volume chamber 372 via the now open exhaust gas transmission line with the main exhaust gas line 442 connected (in which atmospheric pressure or approximately atmospheric pressure is present), and by means of the exhaust gas, which in the control volume chamber 372 flows, pressurized quickly. Accordingly, a pressure difference across the piston quickly develops 348 and forces the piston 348 , against the biasing force of the spring 356 to move into the closed position, which in 3B is shown. In the closed position, the piston locks 348 the gas flow between the vacuum stage 322 and the pump inlet port 340 and thereby keeps the vacuum pressure in the vacuum stage 322 upright. The membrane 368 Prevents exhaust gas from escaping quickly from the control chamber 362 in the vacuum stage 322 flows. However, the gas line-limiting opening allows 339 the exhaust gas, slowly out of the control volumetric chamber 372 through the opening 339 through the pump inlet port 340 and into the pump interior 324 to stream. This little gas flow through the opening 339 can fulfill the function of the gas return flow from the main exhaust gas line 442 through the pump interior 324 and into the pump inlet port 340 To prevent, and thereby prevent oil or particles in the pump interior 334 penetration.

If then the vacuum pump 318 is restarted, the pilot valve 488 switched back to its closed state, again creating a fluidic seal in the exhaust gas transfer line between the VPI valve 314 and the main exhaust pipe 442 will be produced. Because the vacuum pump 318 The vacuum pump begins to develop a vacuum again during this resumed operation 318 gradually the exhaust gas via the opening 339 from the control chamber 372 (And the part of the exhaust gas transport pipe between the control volume chamber 372 and the now closed pilot valve 488 ). The pressure difference across the piston 348 gets lower, and when the pressure in the control volume chamber 372 low enough, the piston moves 348 (supported by the spring 356 ) back to the open position, whereby the fluid connection between the vacuum pump 318 and the vacuum stage 322 is restored.

From the foregoing, it can be seen that the vacuum pump 318 as in other embodiments disclosed herein, provides a VPI valve that is hermetic and does not require ambient air for its operation.

As noted above, a vacuum pump as disclosed herein may be a scroll pump. The pumping stage of the scroll pump may include a stationary scroll and a revolving scroll which is drivable to orbit relative to the stationary scroll, as will be appreciated by those skilled in the art. Examples of scroll pumps are further described, for example, in US Patent Application Publication Nos. US 2014/0271233 A1 ; US 2014/0271242 A1 ; and US 2016/0201674 A1 described; the contents of each are entirely incorporated by reference into this document.

It should be understood that terms such as "connect (communicate)", "in ... connect with (in ... communication with)" (eg, a first component "is connected to" or "is in connection with" a second component ) are used herein to indicate a structural, functional, mechanical, electrical, signal, optical, magnetic, electromagnetic, ionic or fluidic relationship between two or more components or elements, the circumstance as such that one component communicates with a second one Component does not preclude the possibility that additional components may be present therebetween, and / or may be operatively associated with or engaged with the first and second components.

It is understood that various aspects or details of the invention may be changed without departing from the scope of the invention. Furthermore, the foregoing description is for the purpose of illustration only and not for the purpose of limitation - the invention is defined by the claims.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4785851 [0006]
• US 2014/0271233 A1 [0048]
• US 2014/0271242 A1 [0048]
• US 2016/0201674 A1 [0048]

Claims (20)

 A vacuum pump shut-off (VPI) valve comprising: a pump inlet housing enclosing an inlet interior; a valve element disposed in the inlet interior, wherein the valve element is configured to switch between an open state of the VPI valve and a closed state of the VPI valve and configured to switch to the closed state in response to a pressure in the open state, the valve element allows fluid flow between a vacuum pump and a vacuum chamber via the inlet interior, and in the closed state, the valve element blocks fluid flow between the vacuum pump and the vacuum chamber; and a pilot valve configured to connect to the inlet interior and an internal exhaust conduit of the vacuum pump, the pilot valve being switchable between an open pilot valve position and a closed pilot valve position; in the open pilot valve position, the pilot valve allows an exhaust gas from the internal exhaust passage to exert a pressure on the valve element, which is effective for switching the valve element to the closed state, and in the closed pilot valve position, the pilot valve blocks the flow of exhaust gas from the internal exhaust passage to the valve element.  The VPI valve according to claim 1, comprising a valve seat disposed in the inlet interior, the valve element having a piston movable between an open piston position corresponding to the open state of the VPI valve and a closed piston position extending toward corresponds to the closed state of the VPI valve, and wherein in the closed piston position, the piston contacts the valve seat.  The VPI valve of claim 2, comprising a control volumetric chamber disposed in the inlet interior and at least partially bounded by the piston, wherein movement of the piston changes a volume of the control volute chamber. The VPI valve of claim 3, comprising a flexible diaphragm secured to the pump inlet housing and the piston and at least partially defining the control volute chamber, the flexible diaphragm moving with movement of the piston.  The VPI valve of claim 3, wherein the control volume chamber is enclosed such that the control volume chamber is at least partially fluidly isolated from the vacuum chamber.  The VPI valve according to claim 3, comprising an inlet port in communication between the inlet interior and the vacuum pump, and a conduit-defining opening in communication between the inlet port and the control volumetric chamber.  The VPI valve according to claim 1, comprising a flexible membrane disposed in the inlet interior and configured to at least partially fluidically isolate the pilot valve from a portion of the inlet interior connected to the vacuum chamber.  The VPI valve according to claim 1, comprising a spring configured to bias the valve element into switching to the open state.  The VPI valve of claim 1, wherein the pilot valve is configured to be normally open and to switch to the closed pilot valve position in response to receiving power.  A vacuum pump comprising: the VPI valve according to claim 1; a pump body, wherein the internal exhaust pipe is disposed in the pump body; a first exhaust gas transfer line providing fluid communication between the internal exhaust gas line and the pilot valve; and a second exhaust gas transfer line providing fluid communication between the pilot valve and the control volute chamber. The vacuum pump of claim 10, wherein the pilot valve is configured to be maintained in the closed pilot valve state in response to receiving power, and further comprising a pump element, a motor configured to drive a movement of the pump element, and a power source configured to provide power to both the vacuum pump and the pilot valve and cut power to the pilot valve in response to the engine stopping operation. The vacuum pump of claim 10, wherein the first exhaust gas transfer line and the second exhaust gas transfer line are fluidically isolated from an environment outside the vacuum pump. The vacuum pump according to claim 10, comprising a scroll pump stage disposed in the pump body and connected to the inlet interior and the internal exhaust gas line.  A vacuum pump shut-off (VPI) valve comprising: a valve seat disposed in the inlet interior; a piston disposed in the inlet interior, the piston being movable between an open piston state and a closed piston state; in the open piston state, the piston allows fluid flow between a vacuum pump and a vacuum chamber via the inlet interior, and in the closed piston state, the piston contacts the valve seat and blocks fluid flow between the vacuum pump and the vacuum chamber; a control volumetric chamber disposed in the inlet interior and at least partially bounded by the piston, wherein movement of the piston changes a volume of the control volumetric chamber; and a pilot valve configured to connect to the control volumetric chamber and an internal exhaust conduit of the vacuum pump, the pilot valve being switchable between an open pilot valve position and a closed pilot valve position, wherein in the open pilot valve position, the pilot valve allows exhaust gas from the internal exhaust passage to pressurize the control volute chamber to a pressure effective to move the piston to the closed piston state, and in the closed pilot valve position, the pilot valve blocks the flow of exhaust gas from the internal exhaust passage to the control volute chamber.  A vacuum pump comprising: the VPI valve according to claim 14; a pump body, wherein the internal exhaust pipe is disposed in the pump body; a first exhaust gas transfer line providing fluid communication between the internal exhaust gas line and the pilot valve; and a second exhaust gas transfer line providing fluid communication between the pilot valve and the inlet interior.  A vacuum system comprising: a vacuum pump having an internal exhaust pipe; a vacuum chamber; a vacuum shut-off (VPI) valve which is switchable between an open VPI valve state and a closed VPI valve state, wherein in the open VPI valve state, the VPI valve allows fluid flow between the vacuum pump and the vacuum chamber, and in the closed VPI valve state, the VPI valve shuts off the fluid flow between the vacuum pump and the vacuum chamber; and a pilot valve which is connected to the internal exhaust pipe and the VPI valve, wherein the pilot valve is switchable between an open pilot valve state and a closed pilot valve state, wherein in the open pilot valve state, the pilot valve allows the exhaust gas to flow from the internal exhaust passage to the VPI valve at a pressure effective to switch the VPI valve to the closed VPI valve state, and in the closed pilot valve state, the pilot valve blocks the flow of exhaust gas from the internal exhaust passage to the VPI valve.  The vacuum system of claim 16, wherein the VPI valve comprises: a pump inlet housing enclosing an inlet interior; a valve element disposed in the inlet interior, the valve element configured to switch between the open VPI valve state and the closed VPI valve state and configured to switch to the closed VPI valve state in response to the pressure; wherein, in the open pilot valve state, the pilot valve allows the exhaust gas from the internal exhaust passage to exert a pressure on the valve element. The vacuum system of claim 16, wherein the VPI valve comprises: a pump inlet housing enclosing an inlet interior; a valve seat disposed in the inlet interior; a piston disposed in the inlet interior, the piston being movable between a first position corresponding to the open VPI valve state and a second position corresponding to the closed VPI valve state, wherein in the first position, the piston allows fluid flow between the vacuum pump and the vacuum chamber via the inlet interior, and in the second position, the piston contacts the valve seat and blocks fluid flow between the vacuum pump and the vacuum chamber; and a control volumetric chamber disposed in the inlet interior and limited at least in part by the piston, the movement of the piston changing a volume of the control volute chamber, wherein, in the open pilot valve state, the pilot valve allows the exhaust gas to pressurize the control volute chamber. The vacuum system of claim 16, comprising a first exhaust gas delivery line providing fluid communication between the internal exhaust gas line and the pilot valve and a second exhaust gas transfer line providing fluid communication between the pilot valve and the VPI valve.  The vacuum system of claim 16, wherein the vacuum pump is a forepump, and further comprising a high vacuum pump connected to the vacuum chamber, and wherein: in the open VPI valve state, the VPI valve allows fluid flow between the backing pump and the high vacuum pump, and in the closed VPI valve state, the VPI valve shuts off fluid flow between the backing pump and the high vacuum pump.

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