The present invention relates to a lasing gas recycling; or, more particularly, to the recycling of neon gas that has been discharged from an excimer laser.
Excimer lasers generate laser action from a high purity lasing gas. A typical lasing gas is comprised of at least one part noble gas (e.g., argon, krypton, xenon, neon, etc.), one part halogen gas (e.g., chlorine or fluorine), and one part buffer gas (e.g., helium). The lasing gas is stimulated within a lasing chamber to generate laser action. During operation of the laser, some portion of the halogen gas is depleted by reaction with materials inside of the chamber (e.g., hydrogen chloride). Impurities are introduced as the halogen gas is depleted. These impurities can reduce the output power of the laser via light absorption, scattering, and degradation. In some instances, output power can be significantly reduced by concentrations of impurities as low as 0.1% (1000 ppm) of the lasing gas.
The output power of a laser can be at least partially restored by replacing the depleted halogen in the lasing chamber. Most lasers cannot, however, be restored to full output power without removing said impurities from the lasing chamber. Thus, all of the lasing gas is typically discharged from the lasing chamber at some point, including any noble gases contained therein. Sources of noble gas are rare on earth, making supplies inherently limited. Noble gases are also expensive to purify, when found. Continual demand for lasing technologies has also caused global shortages of most purified noble gases, such as helium and neon, further exacerbating their cost. As a result, it has become increasingly expensive to operate gas discharge lasers because of the costs associated with having to continually replace high purity noble gases when removing contaminants from the lasing chamber.
Attempts have been made to reduce these costs by re-purifying at least a portion of the discharged noble gas. Many known processes utilize extreme temperature fluctuations. For example, some purification processes use cryogenic traps to condense certain impurities (e.g., carbon tetrachloride) by cooling the discharged lasing gas from room temperature to a reaction temperature of between 90 to 130° K (or between -298 to -225° F.) and then heating it back up. In other examples, certain contaminants (e.g., nitrogen or water) are removed by a catalytic process, wherein the discharged lasing gas may be heated from room temperature to a reaction temperature of between 250 to 700° C. (or between 482 to 1,292° F.) and then cooled back down. These types of processes are common.
Utilizing processes that require extreme temperature fluctuations can increase the cost and complexity of the underling mechanical systems. Therefore, most of these processes are suitable for industrial scale purification, yet unworkable in situ. Moreover, many of these processes can only be realized with either permanent equipment having an extensive footprint, such as a cooling tower; or costly modifications to existing lasers, such as having to convert a laser from one input of lasing gas to another. Because of their complexity, many of these processes also require considerable technical support to ensure their continued operation, adding even more costs.
A gas recycling system comprises a series of removal units configured to receive a flow of contaminated lasing gas and output a flow of purified neon gas, the units comprising: a set of filters that remove fouling elements from the flow of contaminated lasing gas; a first set of parallel trap modules that remove hydrogen from the flow of contaminated lasing gas; and a second set of parallel trap modules that remove xenon from said flow of contaminated lasing gas; and a storage vessel that receives said flow of purified neon gas from at least one of the plurality of removal units.
A gas recycling process comprising moving a flow of contaminated lasing gas through a series of removal units including a set of filters that remove a fouling element from the flow of contaminated lasing gas; a first set of traps that remove at least hydrogen from the flow of contaminated lasing gas; and a second set of traps that remove at least xenon from said flow of contaminated lasing gas; outputting a flow of purified neon gas from one of the series of removal units; and blending the flow of purified neon gas with at least one blending gas so as to create a lasing gas.
A neon gas purification kit comprising a series of removal units configured to receive a flow of contaminated lasing gas and output a flow of purified neon gas, said removal units including a plurality of filters configured to remove fouling elements from the flow of contaminated lasing gas; at least one first set of traps configured to remove at least hydrogen from the flow of contaminated lasing gas; and at least one second set of traps configured to remove at least xenon from said flow of contaminated lasing gas; and one or more moving elements configured to move said flow of contaminated lasing gas through the series of removal units, wherein each filter and trap is independently removable.
The present invention pertains to the recycling of a noble gas that has been discharged from a laser within a flow of contaminated lasing gas. In the follow paragraphs, various exemplary systems, processes, kits, and related inventions are described with reference to the recycling of a flow of contaminated lasing gas that has been discharged from an excimer laser. Said gas flow is described as having one part noble gas and one part halogen gas. In each example, the laser is a hydrogen chloride excimer laser that generates laser action from a lasing gas, wherein the noble gas is neon and the halogen gas is hydrogen chloride. These neon-specific examples are provided for ease of description as the present invention is not limited to a particular type of laser or lasing gas.
One embodiment of the present invention is illustrated in
(I) a removal stage (points B-D);
(II) a storage stage (point D);
These units can also be arranged at the front end of the process.
(III) a processing stage (point E); and
(IV) a packaging stage (point F).
Exemplary realizations of each stage I-IV are illustrated, respectfully, in
First as shown in
One embodiment of removal stage (I) is illustrated in
In a low flow embodiment of system 10, the flow rate of contaminated lasing gas moving through removal stage (I) is determined by the pressure of the lasing gas in the lasing chamber. If the gas pressure is sufficiently high, then this configuration may desirably reduce system complexity. In other embodiments, such as in
Point A is marked on
In the removal stage (I), this flow of contaminated lasing gas is moved from point A and through removal units 30, 40, and 50 (
In an alternative embodiment as shown in
Removal units 30, 40, and 50 of
Before unit 30, as discussed above, there may be a set of traps 110. The specifications of the lasing gas at point H are as follows:.
Removal unit 30 of
However constructed, at least a portion of each filter 32A-B may be removed for replacement or regeneration after a predetermined amount of contaminated lasing gas flows therethrough. The PIT symbols 15 represented in the drawings are pressure indicators, such as digital indicators. A control valve 16 is utilized to seal unit 30 from units 40 and 50, if needed.
Each filter 32A and 32B in
As shown, the amount of hydrochloric acid in the flow of contaminated lasing gas has been reduced to appropriate levels. The contaminated lasing gas flows into and out of filters 32A-B at the same temperature and pressure, thereby allowing the same conduit 12 to be used throughout system 10. The pressure inside of each filter 32A and 32B may be controlled upstream by a regulator.
Removal unit 40 of
Each of traps 42A-B in
As shown, the amount of water, carbon dioxide, and hydrogen in the flow of contaminated lasing gas has been reduced to appropriate levels. The predetermined maximum amount of contaminated lasing gas for traps 42A-B in this example is approximately equal to a volume of 315,000 liters. Said gas is input to and output from traps 42A-B at the same temperature and pressure, thereby allowing use of conduit 12.
Removal unit 50 of
In contrast to above, however, the use of chemical absorption in traps 52A-B allows one or more contaminants to be recovered their adsorbent surfaces in a purified form. Each of traps 52A-B in
As shown, the amount of xenon in the gas flow has been significantly reduced. The predetermined maximum amount of Xenon for traps 52A and 52B in this example is approximately equal to 21,000 liters. Additional sets of traps 52A-B may be used to ensure that predetermined maximum amount for unit 50 is approximate equal to that of units 30 and 40. Gas is input to and output from unit 50 at the same temperature and pressure. Process steps for recovering xenon are described below.
According to process described herein, a flow of purified noble gas is output from point D without the associated complexity of cryogenic traps, catalytic processes, or the like. Within storage stage (II), a volume of said flow of purified noble gas is stored, at least temporarily, within system 10. An exemplary storage stage (II) is illustrated in
In processing stage (III), the steady flow of purified noble gas is supplied from storage stage (II). In the embodiment shown in
An exemplary processing stage (III) is illustrated in
As shown, the flow rate of purified noble gas at point E has been reduced by air removal unit 70 to permit blending. A pressure regulating valve 17 is used to further direct said flow of gas through a blending source valve 18.
To complete processing stage (III), the flow of purified noble gas from point E is mixed with one or more gases flowing from blending source unit 80. As shown in
Packaging stage (IV) converts the purified gas output from processing stage (III) into an immediately useable form. An exemplary packaging stage (IV) is illustrated in
The ongoing example is specific to neon gas. Therefore, as shown in
Accordingly, an amount of neon has been captured from a flow of contaminated lasing gas (point A), blended with another gas to create a lasing gas (point E), and then packaged for immediate use by a specified excimer laser (point F).
Blending vessel 24 is attached to an exit port 24C that permits access to a validation sensor configured to verify the purity of lasing gas at point F. Moving element 26 is attached to an exit port 24D that allows a volume of the purified gas to be purged during start-up, for example. A control valve 16 is attached to ports 24C and 24D. A total of twelve tanks 92 are shown in
An exemplary set of gas purification processes are also enabled by the description of system 10 set forth above and illustrated in
Each filter 32A-B has been described as independently removable. The respective core element of each filter may also be independently removable. Accordingly, this exemplary process may further comprise removing at least a portion of filters 32A-B; and replacing or regenerating said portion. The removal timing may be proportionate to the amount of contaminated lasing gas flowing across filters 32A-B or their respective core elements. Each of traps 42A-B and traps 52A-B has also been described as independently removable. The respective adsorbent surfaces said traps may also be independently removable. Either way, an exemplary process may further comprise removing at least either the first or second adsorbent surface; and replacing or regenerating said adsorbent surface. The removal timing may also be proportionate to the amount of contaminated lasing gas.
If xenon recovery is desired, the said process may further comprise removing at least one second adsorbent surface; exposing said second surface to a temperature variation; and capturing any xenon released from said surface. An embodiment of packing unit 90 may be incorporated into this exemplary process. For example, said process may further comprise packaging, with packaging unit 90, a stored volume of said lasing gas in at least one lasing gas storage container 92. This process may further comprise attaching the at least one lasing gas storage container 92 to a lasing chamber; and moving an amount of the stored volume of lasing gas into the lasing chamber. Container 92 may be directly attachable to a lasing chamber by, for example, an alternate embodiment of hookup 11.
Exemplary gas purification kits are also described with reference to the various embodiments of system 10 set forth above. 21. An exemplary kit may comprise a series of removal units configured to receive a flow of contaminated lasing gas and output a flow of purified noble gas. In accordance with examples set forth above, said removal units may comprise one more units 30, each having a plurality of filters 32A-B configured to remove fouling elements from the flow of contaminated lasing gas; one or more units 40, each having at least one first set of traps 42A-B configured to remove at least hydrogen from the flow of contaminated lasing gas; and one or more units 50, each having at least one second set of traps 52A-B configured to remove at least xenon from said flow of contaminated lasing gas; and one or more compressors or pumps, such as pump 20, that are configured to move said flow of contaminated lasing gas through the series of removal units 30, 40, and 50, wherein each filter and trap is independently removable from one of said removal units. Any number of additional traps or filters, or any additional length of conduit 12, may also be included.
Some kits according the present invention may allow for optional enhancements. For example, an exemplary kit may further comprise one or more digital flow meters configured to measure an amount of contaminated lasing gas flowing through each removal unit and communicate with a third party when said measurement approaches a predetermined maximum amount. Other kits may comprise an air removal unit 70. Still other kits may comprise one or more blending gas storage canisters 84A-B; and a processing unit configured to operate blending source valves 18 and 82 to as to blend the flow of purified noble gas with the blending gases contained in the one or more blending gas storage canisters so as to create a lasing gas.
Although the invention herein is described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of said invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
The present application claims the benefit of the filing date of U.S. Provisional Patent Application No. 62/252,786 filed Nov. 9, 2015, the disclosure of which is hereby incorporated herein by reference.
Number | Date | Country | |
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62252786 | Nov 2015 | US |