KR101244492B1 - Apparatus for inhibiting the propagation of a flame front - Google Patents

Abstract

Apparatus is described for inhibiting the propagation of a flame front ignited by a pumping mechanism drawing a waste stream from a process chamber. A combustion chamber comprises an inlet for receiving the waste stream exhaust from the pumping mechanism and means for generating a flame for burning a flammable component of the waste stream. A pressure detector detects a pressure at a location through which the waste stream is drawn by the pumping mechanism, and a flame detector detects the presence of a flame in th combustion chamber. A controller regulates the delivery of at least one process fluid to the process chamber if the detected pressure is greater than a pressure above which the flame front can be sustained by the waste stream, or if there is no flame present in the combustion chamber.

Description

Apparatus and method for preventing radio waves in front of flames {APPARATUS FOR INHIBITING THE PROPAGATION OF A FLAME FRONT}

The present invention is directed to an apparatus and method for aspirating a waste stream from a process chamber and for preventing propagation of a flame front that is ignited by a pumping mechanism.

As semiconductor processes become more complex, the fluids used in these processes become more and more active. The atmosphere in the vacuum pump used to empty the process chamber increases the risk associated with this process, which may include pockets of flammable gas or may be extremely flammable. Vacuum pumps were not typically designed in such an environment. The vacuum pumping mechanism typically includes a metal rotor that interacts with the metal stator to transport fluid from the inlet to the outlet of the vacuum pump. Parts of this pumping mechanism are required to have close tolerances to prevent the pumped fluid from leaking back towards the inlet of the pump. Proximity to these two metal parts is due to its characteristic that any impingement of the parts tends to indicate an ignition source by generating a spark. If the advancing nature of the treatment is undertaken by such pumps, the deformation (via corrosion) of the metal parts can similarly increase such that these tolerances are significantly reduced. In addition, the reaction of materials used in semiconductor processing often leads to the deposition of materials on the surfaces of the rotor and stator. This deposition further reduces the tolerance such that the alignment of the parts of the pumping mechanism is affected and the metal parts are hit.

If a flammable atmosphere is in contact with the ignition point, an explosion follows. If such an explosion leads to damage to the device, safety issues may arise. In the event of a catastrophic collapse of ignition propellants that may form from parts of the pump, it creates a dangerous environment for any other facility in the vicinity, ultimately for those located in the area. If the collapse is less destructive, leakage of combustible gases can occur in the environment surrounding the device. If other sources of ignition are in these areas, there is a risk of further explosion. In case of damage caused by this explosion, the entire pumping device needs to be shut down to allow maintenance to be undertaken. This is followed by downtime for the overall process system and therefore with manufacturing losses.

Therefore, in the prior art, it was considered necessary to minimize the risk of such an explosion occurring in a vacuum pump. For example, it is known to introduce a large amount of inert gas into a vacuum pump to dilute the combustible mixture in the pump to bring the concentration of the mixture well below the lower explosion limit of the particular mixture. In this way, it was believed that no flammable environment would ever occur, so that explosions could be prevented in the pump. However, if a significant amount of inert gas is introduced into the pump, the volumetric capacity of the pump and any abatement system provided downstream from the pump must be increased to accommodate the increased volume of fluid. Since space is important in semiconductor processing tools, it is necessary to avoid any increase in the capacity of such devices. There is also considerable cost associated with installing and operating larger capacity devices.

In addition, if the mixing between the combustible mixture and the inert gas is not particularly good, it is possible that pockets of combustible gas are formed in the pump. This is particularly likely to be introduced in the middle of stopping the pump to avoid fluctuations in the upstream process chamber. In such a scenario, some of the inert gas may be conveyed back towards the process chamber to effect some dilution in the lower pressure region, but the amount is insufficient to achieve an appropriate dilution level, that is to say that the mixture (or at least of the mixture) Pockets) remain within the flammability range.

It is an object of at least a preferred embodiment of the present invention to find a means of solving these and other problems.

According to one embodiment of the present invention, there is provided an apparatus for preventing propagation of a flame front ignited by a pumping mechanism of a vacuum pumping device that sucks a waste stream from a process chamber, wherein the apparatus is aspirated by the pumping mechanism. Means for detecting pressure at a location to be made; And means for coordinating delivery of at least one kind of process fluid to the process chamber when the detected pressure is higher than the pressure capable of sustaining the flame front by the waste stream.

The apparatus may include a foreline for transporting the waste stream from the process chamber to the pumping mechanism. The detection means can be arranged to detect the pressure in the foreline.

The adjusting means may comprise at least one shutoff valve for preventing the transfer of at least one kind of process fluid to the process chamber. The adjusting means may comprise a controller for receiving a signal indicative of the detected pressure. The shutoff valve can be controlled by a controller.

The vacuum pumping device can include an additional pumping mechanism located upstream of the pumping mechanism. Further pumping mechanisms are preferably provided by booster pumps, for example Roots blowers.

Means for cooling the waste stream may be provided between the process chamber and the pumping mechanism. The booster pump described above can act as a cooling mechanism. Alternatively, it may be provided as a separate feature, especially if the need for additional pumping capacity is minimal. The cooling means comprise an internal cooling mechanism arranged in the foreline, for example one or more cooling baffles, one or more cooling fingers and / or one or more cooling coils. Alternatively, the cooling means may comprise an external cooling mechanism, for example a Peltier device and / or a cooling coil, located adjacent to the outer surface of the foreline.

The apparatus may comprise an exhaust pipe connected to the exhaust port of the vacuum pumping apparatus. The pipe may be configured to suppress escalation of the explosion of deflagration occurring within the pipe. The exhaust pipe may include at least one of one or more explosion obstacles, one or more purge ports, one or more variable diameter zones, and one or more groups of variable orientation zones.

Means may be provided for delivering inert gas to the waste stream depending on the pressure detected. Such inert gas delivery means may comprise at least one purge port located in the stator of the pumping mechanism or a purge port which may be positioned to introduce an inert gas into the waste stream exiting from the pumping mechanism. The delivery means may comprise heating means configured to heat the purge gas prior to delivery of the purge gas.

The device may comprise a removal device for receiving a waste stream discharged from the pumping mechanism. The removal device may comprise a combustion chamber having an inlet for receiving a waste stream discharged from the pumping mechanism. The combustion chamber may also comprise means for generating a flame to combust the combustible components of the waste stream in the combustion chamber. In the case where the combustion chamber is thus configured, the removal device may comprise means for detecting the presence of flame in the combustion chamber.

The adjusting means may be configured to regulate the delivery of at least one kind of process fluid to the process chamber when no flame is detected in the combustion chamber. Means are provided for delivering an inert gas to the waste stream discharged from the pumping mechanism when no flame is present in the combustion chamber.

The inlet of the combustion chamber is configured to prevent flame from the combustion chamber from propagating from the combustion chamber to the waste stream upstream.

The adjusting means may depend not only on the presence of flame in the combustion chamber but also on the pressure at the inlet region of the pump. As a result, according to another embodiment of the present invention, there is provided an apparatus for preventing propagation of a flame front that is ignited by a pumping mechanism that draws waste streams from a process chamber. The apparatus comprises a combustion chamber comprising an inlet for receiving a waste stream from a pumping mechanism and means for generating a flame to combust the combustible components of the waste stream; Means for detecting pressure at a location at which the waste stream is sucked by the pumping mechanism; Means for detecting the presence of flame in the combustion chamber; And means for coordinating delivery of at least one kind of process fluid to the process chamber when the detected pressure is higher than the pressure capable of sustaining the flame front by the waste stream or when there is no flame in the combustion chamber.

The adjustment of the supply only depends on the presence of the flame in the combustion chamber located downstream of the pumping mechanism. As a result, according to another embodiment of the present invention, there is provided an apparatus for preventing propagation of a flame front that is ignited by a pumping mechanism that draws waste streams out of a process chamber, the apparatus comprising receiving waste streams from a pumping mechanism. A combustion chamber comprising an inlet for and a means for generating a flame to combust the combustible components of the waste stream; A flame detector for detecting the presence of flame in the combustion chamber; And means for coordinating delivery of at least one kind of process fluid to the process chamber when no flame is present in the combustion chamber.

According to yet another embodiment of the present invention, a method is provided for preventing propagation of a flame front ignited by a pumping mechanism that sucks a waste stream from a process chamber, the method being provided at a location where the waste stream is sucked by the pumping mechanism. Detecting pressure; And coordinating delivery of at least one kind of process fluid to the process chamber when the detected pressure is higher than the pressure capable of sustaining the flame front by the waste stream.

According to another embodiment of the present invention, there is provided a method of preventing propagation of a flame front that is ignited by a pumping mechanism that draws waste streams from a process chamber, the method comprising a combustion chamber for receiving waste streams exiting the pumping mechanism. Detecting the presence of a flame in the; And coordinating delivery of at least one kind of process fluid to the process chamber when no flame is present in the combustion chamber.

According to another embodiment of the present invention, there is provided a method of preventing propagation of a ignited flame front by a pumping mechanism of a vacuum pump that draws waste streams from a process chamber, the method comprising the presence of a flow of purge gas into the vacuum pump. Detecting; And coordinating delivery of at least one kind of process fluid to the process chamber when no purge gas is delivered.

According to yet another embodiment of the present invention, a method is provided for initiating operation of a process system, the system comprising: a process chamber through which at least one type of process fluid is supplied through an inlet thereof; A vacuum pumping device connected by a foreline to the outlet of the process chamber to suck waste streams from the process chamber; And a detector for detecting an error condition of the system, the method comprising: turning on the system; Detecting a first status signal from the detector indicating an error condition of the system to ensure that the detector is activated; Continuously initiating operation of the vacuum pumping apparatus; Detecting a second status signal indicative of an operational status of the system; And continuously initiating delivery of the process fluid to the process chamber to allow the process to be initiated.

The features described above in connection with the apparatus of the system embodiments of the present invention are equally applicable to the method embodiment, and vice versa.

By providing pressure detection means and / or flame detectors and having the source of flame material depend on it, it is possible to eliminate and suppress potential damage caused by or associated with explosions in a vacuum pump as described above. As possible, it is possible for the flammable mixture to be pumped to increased levels.

Rather than preventing the flammable mixture from occurring entirely, various features are introduced to prevent the gradual spreading of any deflagrations that may occur, thus preventing or at least limiting the damage that may be done by deflagration. All of this can be achieved using equipment of standard capacity rather than increasing consumable materials associated with volume capacity. As a result, the costs associated with preparing and operating such equipment can be reduced.

In known pumping devices in which it is recognized that ignition may occur, conventional flame protection devices are typically implemented at the inlet and / or outlet of the vacuum pump. However, such devices typically lead to reduced values of conductance and corresponding reductions in pumping efficiency. This is especially noteworthy when used in processes that produce depositions that form certain materials as are often found in semiconductor processing. As the deposition is formed in the flame arrester, the open cross-sectional area through which the pumped fluid passes is significantly reduced, further reducing conductance. As a result, it is inappropriate to use a flame arrester in such an environment if frequent repair and maintenance maintenance is avoided.

An embodiment of the present invention is described with reference to the following drawings.

1 schematically shows a first embodiment of an apparatus for preventing propagation of a flame front that is ignited by a pumping mechanism that draws waste streams from a process chamber;

FIG. 2 shows a second embodiment of an apparatus for preventing propagation of a flame front that is ignited by a pumping mechanism that draws waste streams from a process chamber, FIG.

3 is a detailed view of the inlet of the combustion chamber that may be used with the apparatus of FIG. 1, FIG.

4 shows a third embodiment of a device for preventing propagation of a flame front that is ignited by a pumping mechanism that draws waste streams from a combustion chamber;

FIG. 5 is a flow diagram illustrating two fault tolerant initiating systems associated with any of the embodiments described above. FIG.

1 is a process chamber having at least one fluid inlet 20 for introducing therein one or more processing fluids contained therein, for example, a gas typically used in the processing of a sample, such as a semiconductor wafer or flat panel display device. 10 is shown. A shutoff valve 25 is provided at the fluid inlet 20 to selectively block the flow of fluid to the chamber 10. The outlet from the process chamber 10 is connected to the inlet of the vacuum pump 30 through the foreline 40, which includes a pumping mechanism suitable for sucking the waste stream from the process chamber 10. In order to detect the pressure of the waste stream drawn from the vacuum pump 30, a pressure detector 45 is used to determine the local pressure in or in the foreline 40 (as shown). It is provided within the inlet of. A signal indicative of this foreline pressure is output from the pressure detector 45 to the controller 50.

The outlet of the vacuum pump is sequentially connected to the inlet of the removal system 55 via pipe 60. The purpose of the removal may be to be treated more comfortably, for example by a scrubber connected to the exhaust conduit 70 for transporting the waste stream from the outlet of the removal system, or to be safely discharged to the atmosphere via the exhaust conduit 70. To convert one or more species of a waste stream into one or more different components. In this example, a bypass line 80 is provided to connect the pipe 60 directly to the exhaust conduit 70, thereby removing the system before processing in the process chamber 10 and during the time therebetween. Bypassing removal system 55 to allow standby or shut down, thereby reducing costs. At the junction between the bypass line 80 and the pipe 60, a three-way valve 90 controls whether the fluid path from the waste stream passes through the removal system 55 or branches through the bypass line 80. Is provided. Operation of the valve 90 is controlled by the controller 50.

As shown in FIG. 1, a purge system 75 may be provided to introduce amounts of inert gas into the vacuum pump 30. The purge system 75 typically includes one or more purge ports disposed along the length of the vacuum pump 30. Here, a further purge port 65 for introducing an inert gas downstream of the vacuum pump 30 is arranged in the pipe 60, preferably between the outlet of the vacuum pump 30 and the valve 90. Can be. Means for detecting a constant flow rate of purge gas into the vacuum pump 30 and / or into the pipe 60 are preferably provided in the purge system 75.

In this embodiment, removal system 55 includes a combustion chamber where combustion of any combustible component of the waste stream occurs. Flame detector 95 is provided in removal system 55 to detect the presence of flame inside the combustion chamber. The signal indicating this state is output from the flame detector 95 to the controller 50.

When the combustible mixture is generated in the process chamber 10 by treatment carried out on a sample introduced into or placed in the process chamber 10 through the fluid inlet 20, the waste stream comprises the combustible mixture. . As a result, a flammable atmosphere can be generated in the vacuum pump 30. Tests were conducted on a typical vacuum pump (30, BOC Edwards iH160F pump) to ensure that the pump could withstand an initial internal explosion due to ignition of the area of flammable material. These tests showed that the pump can withstand twice the pressure load experienced in the deflagration that starts when the pump overflows the stoichiometric flammable mixture under operating conditions.

The state in the vacuum pump 30 may be a deflagration may occur if there is an ignition source. If the flame front is generated by this deflagration, it is transmitted away from the ignition source through a flammable atmosphere. Conditions encountered by the flame front affect how the flame propagates.

For example, when the flame front is delivered upstream to the foreline 40, it encounters a region of low pressure. For most flammable mixtures, there is a critical pressure below which the mixture does not burn. For most combustible mixtures, this critical pressure is around 60 mbar, but for some mixtures it is as low as 1 mbar. During use of the process chamber 10, the pressure at the foreline 40 of the pump 30 is typically maintained below this threshold pressure. When the flame front encounters this low pressure region, the flame front does not last and the flame is extinguished.

When the flame front is delivered downstream from the pump 30, it runs down the pipe 60 and into the removal system 55. As previously described, the flame in the combustion chamber in the removal system 55 ignites any flammable fluid entering the chamber such that the waste stream exiting the removal system 55 contains little, preferably no combustible components. do. As a result, if the flame front propagates away from the removal system 55, the combustion chamber effectively acts as a flame arrester, so that further propagation of the flame front is prevented and the flame is extinguished because there is no remaining fuel to burn.

Alternatively, if no removal system 55 is provided, or in addition, an inert gas may be introduced into pipe 60 through purge port 65. This inert gas dilutes the flammable mixture below the concentration indicated by the low flammability limit, providing a nonflammable atmosphere. Therefore, when the flame front propagates downstream of the pump 30, it enters the non-combustible atmosphere in the pipe 60 and is extinguished.

In normal operation of the device, the propagation range of the flame front is limited due to the extinguishing effect of the features described above. However, to provide a secure system, it is necessary to implement one or more of the following safety devices.

As previously described, the pressure detector 45 is disposed in the foreline 40 or at the inlet of the pump 30. This detector 45 is its local pressure with a controller 50 that monitors the local pressure in this region to ensure that it maintains it below a predetermined value, typically the critical pressure required to sustain the flame front as described above. Outputs a signal indicating. If this predetermined pressure is exceeded, there is a risk that the flame front can remain in the foreline 40. In addition, if the flame in the combustion chamber of removal system 55 has been extinguished for some reason, the combustible components of the waste stream are not ignited and therefore a flammable atmosphere is maintained. This flammable atmosphere may continue with the flame front propagating through the removal system 55 to the exhaust conduit 70. As described above, the flame detector 95 outputs a signal to the controller 50 to confirm the presence of the flame.

As also described above, a valve 25 is provided at the inlet 20 of the process chamber 10 to block the introduction of at least one kind of process fluid into the process chamber 10 when necessary. The operation of the valve 25 is controlled by the controller 50. If the predetermined pressure in the foreline 40 is exceeded, the flame in the combustion chamber is extinguished or the delivery of purge gas to the pump 30 is interrupted, the controller 50 shuts off the valve 25. And output a signal to the valve 25 to stop the flow of the process fluid into the chamber 10 to instruct it to do so. By blocking this flow of fluid, the concentration of the combustible mixture in the apparatus downstream from the process chamber 10 can be drastically reduced below the lower explosion limit of the combustible mixture to reduce the risk of deflagration.

In addition to shutting off the combustible fluid source, the form of indication to the purge system 75 such that an inert gas overflows the pump 30 so that further removal action further reduces the concentration of the combustible mixture in the pump 30. Furnace controller 50 can be taken. This purge can be transferred from the process chamber 10 to any part of the downstream apparatus, but directly to the pump 30 or through a purge port 65 through one of a number of standard purge ports formed in the stator of the pump. Is passed directly from the outlet of the pump 30 into the preceding pipe 60.

In addition to the removal action described above, additional safety features can be introduced. For example, the controller 50 may control the three-way valve 90 to close the bypass line 80 when the shutoff valve 25 is opened. In other words, when there is any chance of a flammable mixture present in the device, the bypass line is closed so that the fluid must pass through the removal system 55.

Alternatively, when the valve 25 is in the open position, the controller may deliver inert gas through the purge port 65 so that the flammable mixture can be predicted to be downstream from the process chamber 10. The purge system 75 can be directed as low as possible, so that the concentration of the combustible mixture in the pipe 60 is reduced below the lower flammability limit such that any accidental flame front cannot persist in this region.

If the flame front propagates along a sufficiently long path, deflagration can occur under appropriate conditions, resulting in a significantly increased level of damage to the installation and the surrounding equipment. This long path can be seen in the form of a pipe 60 extending between the vacuum pump 30 and the removal system 55. For this reason, it is desirable to design the preceding pipe 60 from the vacuum pump 30 in a manner that prevents the formation of deflagration. Factors affecting this behavior are the diameter of the pipe 60, the length of any straight section of the pipe 60, and the presence of any obstacle, commonly referred to as a deflagration obstacle within the pipe 60.

In some circumstances, the combustible waste stream includes condensable combustible gases. Pipe 60 provides an environment at elevated pressures and low temperatures seen in the upstream portion of the device, and therefore provides conditions particularly suitable for condensation to form. When a pool of flammable liquid is formed, these provide an unpredictable source of flammable material. The velocity of the flammable material from the pool depends on the rate of evaporation of the liquid to the surrounding atmosphere, and in turn includes a number of pressures and temperatures in that region along with the content and saturation level of any liquid present in the gas formation. Depends on the factors

A further problem with the condensable material is that the pool of condensate can be kept much longer in the device if the entire gas mixture can be expected to pass through the device in a predictable manner. In some cases, different processing steps performed within the process chamber incorporate incompatible materials. When the fluids are gases, the process steps can be discreetized so that there is a certain degree of certainty that one step is completed and the waste stream is removed from the system before the next step begins. However, when there is a pool of flammable liquid in the pipe 60 that continues to evaporate, it is still present when the next step of the process is initiated such that incompatible materials are allowed to mix and react in contact with the pipe 60. . A particular example of such a scenario is that the combination of these materials reacts particularly when the cleaning step follows the process step and the combustible mixture is combined with a material having a particularly high oxide content.

Therefore, it is necessary to avoid the formation of such condensate in the first position, etc., and in an alternative configuration, heating elements can be provided around the pipe 60 to prevent the formation of cold spots where fluid can meet condensation. have. In this way, the fluid exiting the pump 30 can be maintained in gaseous form. To further avoid the formation of condensate in the vacuum pump 30 and in the pipe 60, any purge gas delivered through the purge system 75 is preferably heated before delivery. In this way, the waste stream avoids unnecessary cooling and in turn helps to avoid the formation of condensate. In an apparatus configured to heat the purge gas, a sensor is preferably provided for monitoring the temperature of the purge gas. The signal may be generated by the sensor in an environment where the temperature of the purge gas decreases below a predetermined value. The flow of process fluid into the process chamber 10 may be terminated by actuating the valve 25 in response to this signal.

FIG. 2 shows how the vacuum pump 30 and removal system 55 are housed in an enclosure 100 to prevent any flammable fluid leaking from portions of the device in contact with an external ignition source to cause deflagration. do. The environment within this enclosure 100 can be controlled by forcible extraction. As illustrated, an additional detection unit, flow rate detector 105, is integrated into the extraction duct 110 of the enclosure to detect the rate of extraction of the fluid from the enclosure. A signal indicative of the extraction rate is output from the flow rate detector 105 to the controller 50. The controller monitors the extraction rate, and if the rate drops below a predetermined value during operation of the process chamber 10, the above-described action is initiated.

The table below summarizes some of the various removal actions that can be taken.

Condition Status detected and signal sent by Action taken by result Foreline pressure above critical pressure Pressure detector (45) Valve (25) Process fluid shutoff
Process stop Process fluid flow Shut-off valve (25) Three Way Valves (90) Bypass line (85) suppression Purge System (75)
And purge ports (65) Upstream purge gas introduction of the bypass line 80 Enclosure Extraction Error Flow Detector 105 Valve (25) Process fluid shutoff
Process stop Combustion error Flame Detector (95) Valve (25) Process fluid shutoff
Process stop Purge System (750) and Purge Port (65) Upstream side purge gas introduction of removal system 55

The controller 50 can be replaced with a rigid wiring connection between the respective detection components 45, 95, 105 and the valve components 25, 65, 90. Since the detection and valve parts are safety circuit parts, where possible, they are provided in a failsafe configuration, or extras are provided so that their functionality is paired in the device.

Further safety features as shown in FIG. 3 can be implemented in any of the above embodiments including a removal system 55 having a combustion chamber. As mentioned above, when any of the combustible components of the waste stream come into contact with the flames provided in the combustion chamber, they are burned to ashes and thus generate a non-combustible atmosphere. However, there is a risk that the flames can propagate from the inlet into the combustion chamber and into the pipe 60 by the flames contacting the combustible atmosphere. This is commonly referred to as "flash back." As it is necessary to prevent this from occurring, a modified inlet can be provided that provides limitations of and accelerates the accidental waste stream. If the accidental flow rate is large enough, the flame front disclosed in the combustion chamber can be prevented in position with appropriate openings that act to secure the flame front. One particular example of such a device is a thin cross-section metal cone 120 provided at the inlet of the combustion chamber as shown in FIG. 3. If the flame front was locked in a smaller opening, the temperature of the cone would increase rapidly in the direction of increasing diameter. By providing a thermal sensor to the cone, it is possible to easily detect backfire so that the removal action can be carried out as described in detail above.

As mentioned above, for some mixtures, the critical pressure can be as low as 10 mbar for those with high hydrogen content, for example in the presence of oxygen. In this environment, it is necessary to supplement the pumping capacity of the vacuum pump 30 to ensure that the pressure does not exceed the threshold pressure. Alternatively, the thermal environment can be changed such that the value of the critical pressure is raised.

4 shows a third embodiment comprising an additional vacuum pump 130, for example a booster pump, arranged in line with the vacuum pump 30 and connected thereto by a conduit. The booster pump preferably comprises a root pump mechanism. An additional pressure detector 145 is located in the conduit so that further indication of the status of the respective vacuum pumps 30, 130 can be provided to the controller 50.

The introduction of an additional vacuum pump 130 potentially reduces the pressure in the foreline 40 as well as acts to cool the waste stream drawn from the process chamber 10. Quenching cools the waste stream, increasing the value of the critical pressure at which propagation of the flame front continues at pressures below that. In addition, when the flame front propagates upstream from the pumping mechanism and enters the booster pump 130, the cooling action coupled with the restriction on flow as provided by the close tolerances of the booster pump causes the booster pump 130 to be a flame prevention element. To work efficiently.

For some mixtures, cooling alone reduces the critical pressure to a range where no additional vacuum pump 130 is required. In such circumstances, cooling the waste stream may be carried out by alternative means, either inside or outside the foreline. For example, a cooled baffle, finger or cooling coil may be provided within the foreline or the outer surface of the foreline may be cooled using a cooling coil or Peltier device.

In connection with any of the embodiments described above, the detectors 45, 95, 145 can be used to improve the starting procedure of the pump and the safety of the continuous process carried out in the process chamber 10. The initiation procedure is described in the flowchart of FIG. When the power of the entire system is switched on, the detectors 45, 95, 145 recognize an error condition because the upstream pressure of the vacuum pumps 30, 130 exceeds a predetermined threshold pressure, and the flame in the removal system 55 This will not exist. The pump 30 does not allow to start until an "error" signal is received from each such detector, indicating that each detector functions properly. If no "error" status signal is received from each detector, at least one of the detectors is assumed to be defective and the pump is prevented from starting.

Once the pump 30 and the removal system 55 have been initiated and normal operating conditions have been made, the respective detectors must recognize a non-fail or operating condition. Once the operating state has been made throughout, the process can be initiated. As described above, if any of the detectors 5, 95, 145 subsequently exhibits an "error" state, the process is terminated by actuating the valve 25 and one into the process chamber 10. The transfer of the above process fluid is stopped.

Claims (32)

An apparatus for preventing propagation of a flame front ignited by a pumping mechanism of a vacuum pumping device that draws a waste stream from a process chamber, A foreline for conveying a waste stream from the process chamber to a pumping mechanism; Pressure detection means arranged to detect pressure in the foreline where the waste stream is drawn by a pumping mechanism; And Adjusting means for adjusting the delivery of at least one kind of process fluid to the process chamber, The adjusting means comprises at least one shut-off valve for preventing the transfer of at least one kind of process fluid to the process chamber, and a controller for receiving a signal indicative of the detected pressure, The shutoff valve is controlled by the controller and is configured to issue an indication to shut off the shutoff valve when the detected pressure is higher than a predetermined pressure value capable of sustaining the flame front by the waste stream. Characterized Anti-jamming device on the flame front. delete delete delete delete The method of claim 1, The vacuum pumping device comprises an additional pumping mechanism located upstream of the pumping mechanism. Anti-jamming device on the flame front. The method of claim 1, A booster pump located upstream of the pumping mechanism; Anti-jamming device on the flame front. The method of claim 1, Cooling means for cooling the waste stream are provided between the process chamber and the pumping mechanism. Anti-jamming device on the flame front. 9. The method of claim 8, The cooling means comprises a booster pump Anti-jamming device on the flame front. 9. The method of claim 8, The cooling means comprises an internal cooling mechanism disposed in the foreline Anti-jamming device on the flame front. 11. The method of claim 10, The internal cooling mechanism is one or more of a group of one or more cooling baffles, one or more cooling fingers and one or more cooling coils. Anti-jamming device on the flame front. 9. The method of claim 8, The cooling means comprises an external cooling mechanism positioned adjacent the outer surface of the foreline. Anti-jamming device on the flame front. 13. The method of claim 12, The external cooling mechanism is one or more of a group of Peltier devices and cooling coils. Anti-jamming device on the flame front. The method of claim 1, An exhaust pipe connected to the exhaust port of the vacuum pumping device, the pipe being configured to suppress escalation of the explosion of deflagrations occurring within the pipe. Anti-jamming device on the flame front. 15. The method of claim 14, The exhaust pipe includes at least one of at least one explosion obstacle, at least one purge port, at least one variable diameter zone, and at least one group of variable orientation zones. Anti-jamming device on the flame front. The method of claim 1, Means for delivering an inert gas into the waste stream depending on the detected pressure. Anti-jamming device on the flame front. 17. The method of claim 16, The inert gas delivery means comprises at least one purge port located in the stator of the pumping mechanism. Anti-jamming device on the flame front. 17. The method of claim 16, The inert gas delivery means comprises at least one purge port for introducing an inert gas into the waste stream exiting the pumping mechanism. Anti-jamming device on the flame front. 17. The method of claim 16, The inert gas delivery means comprises heating means configured to heat the purge gas prior to delivery of the purge gas. Anti-jamming device on the flame front. The method of claim 1, And a removal device for receiving the waste stream discharged from said pumping mechanism. Anti-jamming device on the flame front. 21. The method of claim 20, The removal device includes a combustion chamber, the combustion chamber having an inlet for receiving a waste stream discharged from a pumping mechanism and means for generating a flame to combust the combustible components of the waste stream in the combustion chamber. Anti-jamming device on the flame front. 22. The method of claim 21, Means for detecting the presence of flame in the combustion chamber Anti-jamming device on the flame front. 23. The method of claim 22, The adjusting means is arranged to regulate the delivery of at least one kind of process fluid to the process chamber when no flame is detected in the combustion chamber. Anti-jamming device on the flame front. 23. The method of claim 22, Means for delivering an inert gas into the waste stream discharged from the pumping mechanism when no flame is detected in the combustion chamber. Anti-jamming device on the flame front. 22. The method of claim 21, The inlet of the combustion chamber is configured to prevent flame from the combustion chamber from propagating from the combustion chamber into an upstream waste stream. Anti-jamming device on the flame front. delete delete delete delete A method of preventing propagation of an ignited flame front by a pumping mechanism that draws waste streams from a process chamber through a foreline, the method comprising: Detecting a pressure in the foreline where the waste stream is sucked by the pumping mechanism; And Adjusting the delivery of at least one kind of process fluid to the process chamber when the detected pressure is higher than a predetermined pressure value capable of sustaining the flame front by the waste stream. How to prevent the propagation of the flame front. delete delete

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